Combined Serum Total Tau-Neurofilament Light Polypeptide Could be Used as Screening Biomarkers For Alzheimer’s Disease

Combined Serum Total Tau-Neurofilament Light Polypeptide Could be Used as Screening Biomarkers For Alzheimer’s Disease | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Combined Serum Total Tau-Neurofilament Light Polypeptide Could be Used as Screening Biomarkers For Alzheimer’s Disease Gözde Ceylan, Nazan Karagöz Sakallı, Hacer Eroğlu Içli, Canan Başaran Küçükgergin, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4761789/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Aim To evaluate the relationship between Alzheimer’s disease (AD) with serum tau, neurofilament light polypeptide (NFL), neurogranin, chitinase-3-like protein 1 (YKL-40) and fatty acid binding protein-3 (FABP-3) as non-invasive markers for early diagnosis of AD. Methods Total 86 AD patients and 30 healthy individuals were recruited. Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) scores, glucose and lipid profile parameters were assessed. Results AD patients were divided into three groups according to CDR: 33 mild, 29 moderate, and 24 severe stages. Serum total tau and NFL levels were higher, neurogranin, YKL-40, FABP-3 not changed in AD patients. Late onset AD was related with higher FABP-3 levels when compared to early onset. Glucose, total cholesterol, LDL were elevated in AD patients. We evaluated for the first time the combined effects of serum total tau-NFL as biomarkers in early diagnosis of AD, and assessed whether the created ROC curves had a strengthening effect on the parameters. Serum total tau values alone had the highest sensitivity and specificity. When NFL-total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone. In addition, NFL was correlated to total tau. Both NFL and total tau were in close relationship with lipid profile parameters. Conclusion Our findings suggest that serum total tau alone is sufficient for the early diagnosis of AD; however, combinations of total tau-NFL biomarkers could also be used as screening tests. High glucose, total cholesterol, LDL support the relationship between AD and metabolic syndrome. Alzheimer’s disease blood biomarkers early diagnosis Figures Figure 1 Figure 2 Figure 3 Introduction Dementia is a worldwide health problem and the fifth-leading cause of death. Alzheimer’s disease (AD) is the most common type of dementia, accounting for 50–75% of all cases. With an increase average lifespan and elderly population AD is expected to become one of the most important health problems in the future. Clinically AD is characterized by progressive memory loss and cognitive decline. Pathologically, AD is characterized by extracellular deposits of β-amyloid (Aβ) plaques, and intracellular neurofibrillary tangles constructed by clusters of hyperphosphorylated tau protein [ 1 ]. Other pathological changes include microglia activation, neuronal degeneration, neuroinflammation, altered protein clearance, lipid metabolism changes, disrupted synaptic function and blood-brain barrier (BBB) integrity [ 2 ]. Previously, most prefered sample on biomarkers of AD was cerebrospinal fluid (CSF).Unfortunately, CSF sampling is an invasive lumbar puncture procedure, having a risk of infection and headaches. Among the other alternative and noninvasive biological samples are peripheral blood and urine. Recently, new candidate markers in noninvasive samples reflecting the underlying AD pathology, are investigating in order to make an early diagnosis. Among these markers, neurofilament light polypeptide (NFL) is the most abundant component of myelinated axons and reflects axonal degeneration [ 2 ]. Neurogranin is a postsynaptic protein playing an important role in synaptic activity and plasticity, and reflects synaptic degeneration [ 2 ]. Chitinase-3-like protein 1 (YKL-40) is a carbohydrate-binding protein secreted by activated macrophages and microglia, and reflects neuroinflammation. Fatty acid binding protein-3 (FABP-3) is important for membrane fluidity, neuronal synapse formation and intracellular lipids transport. FABP-3 indicates lipid metabolism disorder [ 2 ]. In present study, we measured serum total tau, NFL, neurogranin, YKL-40 and FABP-3 levels in mild, moderate and severe stages of AD patients and cognitively healthy controls to evaluate whether these parameters provide information for AD; to evaluate their potential in the early diagnosis and follow-up of AD; to evaluate the relationship between study parameters themselves and with blood glucose and lipid profile in AD. Materials and Methods Study population and sample collection Eighty six AD patients from the Department of Neurology of Bakirkoy Mental Health and Neurological Disorders Training and Research Hospital, and 30 cognitively normal individualas were included. Characteristics of patients with AD and controls were given in Table 1 . The ages and gender distributions in patient and control groups were comparable. Patients with disease onset before 65 years were classified as early onset AD (n = 28), and the remaining patients as late onset AD. Each patient underwent a thorough clinical investigation, including medical history, physical and neurological examination, laboratory screening tests, brain magnetic resonance imaging (MRI) and/or positron emmission tomography (PET). All subjects completed the cognitive tests including Mini-Mental State Examination (MMSE) and Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) scores. Scores lower than 24 for MMSE, and higher than 4 for CDR-SB denotes greater severity of AD. Patients with mild cognitive impairment (MCI) were not included in the study. AD patients were diagnosed according to to the NINCDS-ADRDA criteria [ 3 ]. The exclusion criteria were: a history of neuropsychiatric disease other than AD, metabolic disorders, potential causes of cognitive decline, such as cerebral infarction, subdural hematomas, hydrocephalus, intracranial tumors and infections, alcohol and other substances abuse. This study was approved by the Local Ethics Committee at Istanbul Faculty of Medicine (18.01.2023–1582983). Blood samples were taken after written informed consents were obtained from subjects or their next-of-kin. Fasting venous blood samples were collected, centrifuged within 20–60 minutes at 2500 rpm for 15 min, aliquoted, and stored at -80 ⸰ C until use. Glucose and lipid profile parameters were measured by autoanalyzer (Roche Cobas C6000 Switzerland). Table 1 Characteristics of patients with AD and controls, mean (range) AD (n= 86) Control (n= 30) p - value Age 71.73 (48-91) 72.63 (62-87) 0.377 Sex Male, n (%) Female, n (%) 37 (43) 49 (57) 15 (50) 15 (50) 0.518 Disease onset 65 year, n (%) 28 (32.5) 58 (67.5) - - Family history, n (%) 39 (45) - - Clinical dementia staging scale Mild, n (%) Moderate, n (%) Severe, n (%) 33 (38.4) 29 (33.7) 24 (27.9) - - MMSE 13.76 (0-24) - - CDR-SB 11.31 (4-18) - - Glucose (mg/dL) 120.29 (78 - 267) 100.34 (68 - 140) 0.022 Total cholesterol (mg/dL) 206.10 (96.2 - 292.8) 174 (101.3 - 243.2) 0.004 Triglyceride (mg/dL) 151.04(48.3 - 437) 114.65 (50.7 -255.1) 0.055 LDL- cholesterol (mg/dL) 126.96 (35 - 190) 103.36 (46 - 172) 0.005 HDL- cholesterol (mg/dL) 50.63 (32.3 - 141.6) 54.52 (26.5 - 86.6) 0.258 Total tau (pg/mL) 208.97 (20.2 - 679.62) 48.33 (6.98 - 117.42) < 0.001 NFL (pg/mL) 3.67 (0.11 - 13.23) 1.66 (0.32 - 7.08) 0.002 Neurogranin (ng/mL) 232.83 (58.01- 688.34) 216.17 (70 - 635.96) 0.605 YKL-40 (pg/mL) 56441.1 (21094.22 - 93599.2) 64927.34 (19262.78 - 173242.26) 0.354 FABP-3 (pg/mL) 2552.41 (1065.63 - 6182.5) 2459.9 (717.75 - 6285.03) 0.212 Mann-Whitney U test Abbreviations: AD, Alzheimer’s disease; MMSE, Mini-Mental State Examination; CDR-SB, Clinical Dementia Rating Scale-Sum of Boxes; NFL, neurofilament light polypeptide; YKL-40, chitinase-3-like protein 1; FABP-3, fatty acid binding protein-3 Determining serum total tau, NFL, neurogranin, YKL-40, and FABP-3 levels For measuring of serum total tau, NFL, neurogranin, YKL-40, and FABP-3 ELISA (enzyme-linked immunosorbent assay) test kits were used (TAU, Elabscience E-EL-H0948; NFL, Elabscience E-EL-H0741, Houston, Texas, USA; neurogranin, Mybiosource MBS167225, San Diego, CA, USA; YKL-40, Invitrogen BMS2322, Waltham, MA, USA and FABP-3, Invitrogen BMS2263, Waltham, MA, USA). Statistical analysis Statistical analyses were performed with IBM SPSS Statistics 21.0 package program (IBM Corp. SPSS Inc, Chicago, IL, USA) and GraphPad Prism (10, GraphPad Software, La Jolla, CA, ABD). Data distribution and homogeneity were evaluated with the Kolmogorov-Smirnov and Levene tests. ANOVA was used to compare normally and homogenously distributed data. Kruskall-Wallis and Mann-Whitney U tests were used to compare not-normally and non-homogeneously distributed data. Gender distribution in the study and control groups was analyzed with the chi-square test. The correlation of continuous variables was analyzed by Spearman’s rank correlation analysis. Receiver operating characteristic curve (ROC) analysis was used to evaluate the ability of biomarkers to discriminate between Alzheimer's patients and control groups. For biomarkers with ROC analysis resulted in an area under the curve (AUC) > 0.6 cutoff value, sensitivity, and specificity were calculated. Probability values (p) smaller than 0.05 were regarded as statistically significant. Results Characteristics of patients with AD and controls were given in Table 1 . AD patients had higher serum glucose, total cholesterol and LDL values than in the controls (p = 0.022, p = 0.004, p = 0.005, respectively). As we espected, there were correlations between glucose and lipid profile parameters (p < 0.001 and p = 0.030, data not shown). MMSE scores were gradualy decreased and CDR-SB increased in mild, moderate and severe AD stages (p < 0.001, data not shown). MMSE scores and FABP-3 levels were increased, and CDR-SB decreased in late onset AD when compared with early oncet AD (p = 0.004, p = 0.010, and p = 0.049 respectively, Table 2 ). Table 2 Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) and fatty acid binding protein-3 (FABP-3) in early and late onset Alzheimer’s Disease (AD) Early onset AD Late onset AD p value MMSE (mean (range) 10.96 (0–24) 15.10 (0–24) 0.004 CDR-SB (mean (range) 12.71 (5–18) 10.64 (4–18) 0.049 FABP-3 (pg/mL) 2096.09 (1065.63 -4603.44) 2773.19 (1126.0-6182.49) 0.010 Mann-Whitney U test Serum total tau (p < 0.001) and NFL (p = 0.002) were higher, and neurogranin, YKL-40, and FABP-3 unchanged in Alzheimer’s patients compared to the controls (Figule 1A,B,C,D,E). Total tau levels in all AD subgroups were found to be higher compared to the controls (p < 0.001). Additionally, total tau levels in severe stage were increased according to both mild and moderate stage patients (p = 0.013, p = 0.031, respectively; Fig. 1 A). While serum NFL levels were higher in the moderate and severe stage subgroups compared to controls (p < 0.001), there was no change in the mild stage AD. Significant increase was also observed between severe and mild stage AD (p < 0.001), and between modetrate and mild stage (p = 0.002) (Fig. 1 B). In addition, to test the suitability of total tau and NFL as biomarkers for the diagnosis of AD, ROC curves were drawn. When the cut-off point for total tau was selected as 71.5 pg/mL, sensitivity was found to be 79.1% and specificity was 76.7% (AUC: 0.865, p < 0.001). Regarding to NFL ROC curve, when the cut-off point for NFL was selected as 1.835 pg/mL, sensitivity was found to be 66.3% and specificity was 66.7% (AUC: 0.693, p = 0.002). Combining of total tau and NFL resulted in AUC to be 0.848 (p < 0.001; Fig. 2 ). Serum NFL levels were negatively correlated with MMSE score (p < 0.001, Fig. 3 A). Total tau and NFL levels showed a positive relationship with CDR-SB (p = 0.017, p < 0.001, respectively, Fig. 3 B,C). There was a positive correlation between total tau and NFL levels (p = 0.002; Fig. 3 D). FABP-3 levels were significantly correlated with age (p = 0.006; Fig. 3 E). Additionally, both NFL and total tau were in close relationship with lipid profile parameters (Table 3 ). Table 3 Correlations between serum total tau, neurofilament light polypeptide (NFL) levels with total cholesterol, triglyceride and low density lipoprotein (LDL) cholesterol levels Total tau (r, p value) NFL (r, p value) Total cholesterol 0.299 (0.001) * 0.247 (0.008) * Triglyceride 0.210 (0.024) * 0.196 (0.035) * LDL cholesterol 0.287 (0.002) * 0.199 (0.032) * Spearman correlation test Discussion The aim of this study was to evaluate the relationship between the serum tau, NFL, neurogranin, YKL-40, FABP-3 concentrations and cognitive decline as well as the diagnostic performance of these candidate biomarkers in AD. We found that: a) serum total tau and NFL were higher, neurogranin, and YKL-40 were not changed in AD; b) both serum total tau and NFL levels showed a positive relationship with CDR-SB; c) serum total tau values alone had the highest sensitivity and specificity as diagnostic biomarker; d) when NFL and total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone; e) FABP-3 concenrations were similar in AD and controls, but patients with late onset disease had increased FABP-3 when compared to early onset; f) serum glucose, total cholesterol, and LDL levels were elevated in AD patients; g) NFL was correlated with total tau, and both NFL and total tau were correlated with lipid profile parameters. AD is a neurodegenerative disease representing a significant public health problem with an increasing incidence. Laboratory medicine supports clinicians in the convenient follow-up of AD. The general aim is to recovery the patients’ quality of life with diminish economic costs. Noteworthily, most biomarkers are assesed in the CSF - an prefered biological sample reflecting the neuropathological alterations. However, obtaining CSF is challenging procedure due to its invasive nature and needs highly skilled staff to perform it. Blood collection is much less invasive than lumbar puncture and is performed routinely. Therefore, using serum/plasma for assesment of biomarkers has numerous advantages. Among the main characteristics of AD are tau and Aβ pathologies [ 1 ]. Because tau pathology is more correlated with clinical and cognitive decline than Aβ pathology [ 4 ] we preferred to measure total tau levels in peripheral blood. Tau protein is important for the structural integrity of the neuronal cytoskeleton and axonal transport. The increased abnormal posttanslational phosphorylation of tau protein leads to altered binding to microtubules, polymerization into insoluble double-stranded neurofilaments, forming intraneuronal tangles, and subsequently resulting in neuronal death. Both phosphorylated and total tau are secreted into CSF and peripheral blood. Many studies showed that there is a correlation between total tau concentration in peripheral blood and brain tissue total tau levels evaluated by PET scan [ 5 , 6 ]. In our study, increased serum total tau concentrations in AD patients were found. Moreower, there was a gradualy increase of serum total tau from mild to severe AD stage. Our findings are in line with studies reporting increasing total tau levels in Alzheimer's patients [ 7 – 10 ] and differs from other two studies reporting no clear relationship between serum total tau and AD [ 11 , 12 ]. Because total tau concentrations in peripheral blood reflects axonal degeneration and neuronal death, it can also be considered as a measure of cognitive decline [ 13 ]. Therefore, serum total tau measurement may be useful not only for the early diagnosis of AD, but also for monitoring the dynamic process of neurodegeneration during the progression of the disease. We observed that with the determined cut-off value, 79.1% sensitivity, 76.7% specificity and 0.865 AUC value, serum total tau is a valuable parameter in discriminating between healthy individuals and Alzheimer's patients. Our findings are in line with many studies on the same subject [ 7 – 10 ]. In the spectrum of AD pathologies neurofilaments are molecules reflecting axonal degeneration and providing prognostic information. Neurofilaments are critical for the growth and stability of axons. NFL is the smallest unit among neurofilaments consisting of light, medium, heavy chain, α-internexin and peripherin. In various neurodegenerative, vascular, traumatic and inflammatory diseases NFL is secreted in high amounts into CSF ​​and plasma. Although plasma NFL are 50 times lower than in CSF, it has been shown that CSF and plasma concentrations are well correlated [ 14 , 15 ]. In our study, NFL levels were higher in the AD group compared to the control group. When evaluated according to the clinical dementia score, there were significant increases from the mild stage to the severe stage. However, no significant difference was detected between the control group and mild-stage AD. Accordingly, NFL seems to be a suitable parameter for follow-up rather than early diagnosis of the disease and may be associated with the progression of cognitive decline. Similar to our findings, various studies reporting increased NFL levels in AD linked to brain hypometabolism, brain atrophy and cognitive decline [ 15 – 17 ]. In addition, it is seen from the results that both tau and NFL were correlated with clinical dementia score reflecting cognitive decline. The combined use of NFL and total tau can increase the accuracy of diagnosis of the disease with an AUC value of 0.848. A similar correlation were found Mattsson et al. in their study [ 15 ]. It is well known that the number of synapses correlates with the degree of cognitive disturbances, and synapse loss seen in AD is the strongest pathological finding correlated with cognitive decline [ 18 , 19 ]. So, we decided to measure serum neurogranin levels as marker reflecting synaptic degeneration, but no significant change was detected. Elevated CSF neurogranin levels in patients with AD and mild cognitive impairment compared to controls have been reported previously [ 20 – 22 ]. Additionally, it have been shown that neurogranin 48–76 peptide was domminant in CSF and brain tissue, but was not found in plasma [ 22 ]. Because neurogranin is cleaved enzymatically it can be expected that neurogranin in brain tissue, CSF and peripheral blood has different lenghts fragments. Another reason for the different results may be the different sample matrix used in our study. Neuroinflammation is a common feature of AD pathology, and many epidemiological studies have demonstrated a reduction in the risk and progression of AD after long-term administration of nonsteroidal anti-inflammatory drugs [ 23 ]. YKL-40 is a marker for microglia differentiation and activation, and is considered as indicator of inflammation. Elevated CSF levels of YKL-40 have been found in various infectious and non-infectious disorders of the CNS. It has also been shown that CSF concentrations of YKL-40 are high in AD, but there are also conflicting data [ 24 , 25 ]. In our study, although YKL-40 levels showed an increasing patern, especially in patients with severe dementia, this increase was not statistically significant. The increasing patern may suggest that the inflammatory process and pro-inflammatory signals are more prominent in patients with severe dementia. Excessive inflammation and microglial activation cause exacerbation of neurodegeneration, impairment of synaptic plasticity and cognitive decline [ 26 ]. However, in our study, no correlation was found between YKL-40 and clinical dementia score. The most serious limitation of the use of YKL-40 as a marker appears to be its nonspecificity. Comorbidities such as inflammatory and neoplastic diseases, which are very common in the elderly population, may lead to an increase in YKL-40 concentrations. Therefore, when using YKL-40 as a diagnostic test, it will be necessary to take an in-depth medical history regarding comorbidities and medications used to avoid misinterpretation of biomarker levels. FABP-3 is a biomarker reflecting neuronal membrane damage associated with lipid metabolism, and the usability of this parameter for the diagnosis of AD is being investigated. FABP-3 was isolated from heart muscle, and have widespread tissue distribution. Clinically, FABP-3 can be used as an additional marker in serum after acute myocardial infarction. Many studies have suggested that CSF levels of FABP-3, may have diagnostic importance in the early stages of AD [ 27 , 28 ]. It has been reported that high CSF FABP-3 levels positively correlate with brain Aβ burden in the early stage and are associated with brain atrophy in individuals with Aβ pathology [ 27 , 28 ]. In contrast, Vidal-Pinerio et al. [ 29 ] showed that FAPB-3 levels in CSF predicted brain atrophy in cognitively healthy elderly individuals, independent of amyloidopathy and tauopathy biomarkers. According to these results, it is thought that all measured FABP-3 levels originate from the brain and not from the serum. However, we did not observe any difference in serum FABP-3 levels between groups in our study. This may be due to the fact that the sample we used was serum instead of CSF or that the people in the control group had additional diseases such as cardiovascular disease. It is seen from the results that in late-onset AD FABP-3 concentrations were higher than in early-onset AD. We can doubt that increase of the serum FABP-3 levels in late-onset AD might be a part of the disintegration of lipids and fatty acids in the brain of elderly patients [ 30 , 31 , 32 ]. We suggest that elevated FABP-3 may reflect age-related changes rather than AD pathology. The presence of significant correlation between FABP-3 and age supports this observation. Recently, many studies have been shown that disorders such as diabetes mellitus, obesity, hypercholesterolemia, or hypertension, play a pivotal role in the development of AD [ 33 – 35 ]. Indeed, in our study, serum glucose, total cholesterol and LDL levels were found to be higher in the AD group than in the control group. The brain's glucose requiremend is provided by insulin-independent glucose transporters (GLUT-1, GLUT-3) [ 36 ]. The increased blood glucose causes abnormally high glucose transfer to neurons and triggers gluconeurotoxicity [ 37 ]. Glucose exerts neurotoxic effects through various mechanisms, including the polyol pathway, formation of advanced glycation end products (AGE), and activation of MAP kinases [ 38 ]. There are studies reporting that high AGE levels induce Aβ accumulation in the brain and are associated with cognitive decline in Alzheimer's patients [ 39 ]. On the other hand, even subtle changes in lipid metabolism cause profound effects on cognitive functions. The human brain produces approximately 30% of the cholesterol in the body. Cholesterol is important for maintaining the structural integrity of the plasma membrane for neurons and astrocytes and regulation of membrane fluidity. Cholesterol is also critical for formation of myelin sheaths that provide insulation around axons and increasing the spreading speed of electrical signals throughout the nervous system. Demyelination is used as a biomarker for dementia pathology. Moreover, cholesterol is a component of lipid rafts implicating in signal transduction, cell-cell adhesion, and lipid/protein separation. Therefore, while cholesterol metabolism plays an important role in maintaining brain function, cholesterol dysregulation acts as a potential risk factor for many diseases, including AD. Another link between cholesterol and AD is 24-hydroxycholesterol - the oxidation product of cholesterol occuring only in the brain. This oxysterol can pass through the blood brain barrier. Increased plasma level of 24-hydroxycholesterol in AD probably reflects neuronal death and disordered membrane cholesterol turnover [ 40 ]. On the other hand, high LDL levels induce vascular changes similar to the atherosclertic inflammatory lesions and cause blood-brain barrier permeability impairement [ 41 ]. Tau and Aβ patologies in patients with metabolic syndrome were observed [42,43 ]. Since AD shares many biochemical features of insülin resistance and metabolic syndrome, high serum glucose, total cholesterol and LDL cholesterol levels in AD patients found in our study is not surprising. Moreover, the presense of strong correlations between both serum tau and NFL lipid profile parameters strengthen the hypothesis that dyslipidemia probably is also predisposing factor to AD. Conclusion This study showed increased serum total tau and NFL levels in AD. We evaluated for the first time the combined effects of serum total tau and NFL as biomarkers in early diagnosis of AD, and assessed whether the created ROC curves had a strengthening effect on the parameters. It was observed that serum total tau values alone had the highest sensitivity and specificity. Moreover, when NFL and total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone. In addition, NFL was significantly correlated to total tau. The strong correlations between both tau and NFL with lipid profile parameters in AD support the relationship between AD and metabolic syndrome. Lifestyle changes such as dietary modifications and increased phisical activity even though cannot prevent AD, may have a positive effect on the disease course by causing a decrease in modifiable risk factors. Declarations Acknowledgement This work was supported by the Research Fund of Istanbul University (Project No. TTU-2023-39857). Author contributions Conceptualization: PV, SDA; Methodology: GC, CBK; Sample collection: NKS, HEI, GC; Formal analysis: GC, CBK; Data analysis: PV, GC; Writing-original draft: PV; Writing - review & editing: PV, SDA. Data availability No datasets were generated or analysed during the current study. Ethical approval This study was approved by the Local Ethics Committee at Istanbul Faculty of Medicine (18.01.2023-1582983). Competing interests The authors declare no competing interests. Disclosure statement No potential conflict of interest was reported by the authors. References Katzman R, Saitoh T (1991) Advances in Alzheimer’s disease. FASEB J 5:278-286. Park SA, Han SM, Kim CE (2020) New fluid biomarkers tracking non-amyloid-β and non-tau pathology in Alzheimer's disease. Exp Mol Med 52:556-568. https://doi.org/10.1038/s12276-020-0418-9. McKhan G, Drachman DFolstein M, Katzman R, Price D, Stadlan EM (1984) Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer’s Disease. Neurology 34:938-944. https://doi.org/10.1212/wnl.34.7.939. Pais M, Martinez L, Ribeiro O, Loureiro J, Fernandez R, Valiengo L, Canineu P, Stella F, Talib L , Radanovic M, Forlenza OV (2020) Early diagnosis and treatment of Alzheimer’s disease: new definitions and challenges. Braz J Psychiatry 42:431-441. https://doi.org/10.1590/1516-4446-2019-0735. Mielke MM, Hagen CE, Xu J, Chai X, Vemuri P, Lowe VJ, Airey DC, Knopman DS, Roberts RO, Machulda MM, Jack CR Jr , Petersen RC, Jeffrey L Dage JL (2018) Plasma phospho-tau181 increases with Alzheimer’s disease clinical severity and is associated with tau- and amyloid-positron emission tomography. Alzheimers Dement 14:989-997. https://doi.org/10.1016/j.jalz.2018.02.013. Park JC, Han SH, Yi D, Byun MS, Lee JH, Jang S, Ko K, Jeon SY, Lee YS, Kim YK, Lee DY, Mook-Jung I (2019) Plasma tau/amyloid-β1-42 ratio predicts brain tau deposition and neurodegeneration in Alzheimer’s disease. Brain 142:771-786. https://doi.org/10.1093/brain/awy347. Tsai CL, Liang CS, Lee JT, Su MW, Lin CC, Chu HT, Tsai CK, Lin GY , Lin YK, Yang FC (2019) Associations between plasma biomarkers and cognition in patients with Alzheimer's disease and amnestic mild cognitive impairment: a cross-sectional and longitudinal study. J Clin Med 8:1893. https://doi.org/doi: 10.3390/jcm8111893. Jiang T, Gong PY, Tan MS, Xue X, Huang S, Zhou JS, Tan L, Zhang YD (2019) Soluble TREM1 concentrations are increased and positively correlated with total tau levels in the plasma of patients with Alzheimer's disease. Aging Clin Exp Res 31:1801-1805. https://doi.org/10.1007/s40520-019-01122-9. Dage JL, Wennberg AMV, Airey DC, Hagen CE, Knopman DS, Machulda MM, Roberts RO, Jack CR Jr, Petersen RC, Mielke MM (2016) Levels of tau protein in plasma are associated with neurodegeneration and cognitive function in a population-based elderly cohort. Alzheimers Dement 12: 1226-1234. https://doi.org/10.1016/j.jalz.2016.06.001. Pase MP, Beiser AS, Himali JJ, Satizabal CL, Aparicio HJ, DeCarli C, Chêne G, Dufouil C, Seshadri S (2019) Assessment of plasma total tau level as a predictive biomarker for dementia and related endophenotypes. JAMA Neurol 76:598-606. https://doi.org/10.1001/jamaneurol.2018.4666. Verberk IMW, Slot RE, Verfaillie SCJ, Heijst H, Prins ND, van Berckel BNM, Scheltens P, Teunissen CE, van der Flier WM (2018) Plasma amyloid as prescreener for the earliest alzheimer pathological changes. Ann Neurol 84:648-658. https://doi.org/ 10.1002/ana.25334. De Wolf F, Ghanbari M, Licher S, McRae-McKee K, Gras L, Weverling GJ, Wermeling P, Sedaghat S, Ikram MK, Waziry R, Koudstaal W, Klap J, Kostense S, Hofman A, Anderson R, Goudsmit J, Ikram MA (2020) Plasma tau, neurofilament light chain and amyloid-β levels and risk of dementia; a population-based cohort study. Brain 143:1220-1232. https://doi.org/10.1093/brain/awaa054. Chiu MJ, Chen YF, Chen TF, Yang SY, Yang FP, Tseng TW, Chieh JJ, Chen JC, Tzen KY, Hua MS, Horng HE (2014) Plasma tau as a window to the brain-negative associations with brain volume and memory function in mild cognitive impairment and early Alzheimer’s disease. Hum Brain Mapp 35:3132-3142. https://doi.org/10.1002/hbm.22390. Preische O, Schultz SA, Apel A, Kuhle J, Kaeser SA, Barro C, Gräber S, Kuder-Buletta E, LaFougere C, Laske C, Vöglein J, Levin J, Masters CL, Martins R, Schofield PR, Rossor MN, Graff-Radford NR, Salloway S, Ghetti B, Ringman JM, Noble JM, Chhatwal J, Goate AM, Benzinger TLS, Morris JC, Bateman RJ, Wang G, Fagan AM, McDade EM, Gordon BA, Jucker M (2019) Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer’s disease. Nat Med. 25:277-283. https://doi.org/10.1038/s41591-018-0304-3. Mattsson N, Andreasson U, Zetterberg H, Blennow K (2017) Association of plasma neurofilament light with neurodegeneration in patients with Alzheimer disease. JAMA Neurol 74:557-566. https://doi.org/10.1001/jamaneurol.2016.6117. Zetterberg H (2016) Neurofilament light: a dynamic cross-disease fluid biomarker for neurodegeneration. Neuron 91:1-3. https://doi.org/10.1016/j.neuron.2016.06.030. Lewczuk P, Ermann N, Andreasson U, Schultheis C, Podhorna J, Spitzer P, Maler JM, Kornhuber J, Blennow K, Zetterberg H (2018) Plasma neurofilament light as a potential biomarker of neurodegeneration in Alzheimer’s disease. Alzheimers Res Ther 10:71. https://doi.org/10.1186/s13195-018-0404-9. Scheff SW, Price DA, Schmitt FA, DeKosky ST, Mufson EJ (2007) Synaptic alterations in CA1 in mild Alzheimer disease and mild cognitive impairment. Neurology 68:1501-8. https://doi.org/10.1212/01.wnl.0000260698.46517.8f. Terry RD, Masliah E, Salmon DP, Butters N, DeTeresa R, Hill R, Hansen LA, Katzman R (1991) Physical basis of cognitive alterations in Alzheimer’s disease: synapse loss is the major correlate of cognitive impairment. Ann Neurol 30:572-80. https://doi.org/10.1002/ana.410300410. Mavroudis IA, Petridis F, Chatzikonstantinou S, Kazis D (2020) A meta-analysis on CSF neurogranin levels for the diagnosis of Alzheimer's disease and mild cognitive impairment. Aging Clin Ex Res 32:1639-1646. https://doi.org/ 10.1007/s40520-019-01326-z. Wang L (2019 Association of cerebrospinal fluid Neurogranin with Alzheimer's disease. Aging Clin Ex Res 31:185-189 https://doi.org/ 10.1007/s40520-018-0948-3. Hellwig K, Kvartsberg H, Portelius E, Andreasson U, Oberstein TJ, Lewczuk P, Blennow K, Kornhuber J, Maler JM, Zetterberg H, Spitzer P (2015) Neurogranin and YKL-40: independent markers of synaptic degeneration and neuroinflammation in Alzheimer's disease. Alzheimers Res Ther 7:74. https://doi.org/10.1186/s13195-015-0161-y. McGeer PL, McGeer EG (2013) The amyloid cascade-inflammatory hypothesis of Alzheimer disease: implications for therapy. Acta Neuropathol 126: 479 -497. https://doi.org/10.1007/s00401-013-1177-7. Olsson B, Hertze J, Lautner R, Zetterberg H, Nägga K, Höglund K, Basun H, Annas P, Lannfelt L, Andreasen N, Minthon L, Blennow K, Hansson O (2013) Microglial markers are elevated in the prodromal phase of Alzheimer’s disease and vascular dementia. J Alzheimers Dis 33:45-53. https://doi.org/10.3233/JAD-2012-120787. Mattsson N, Tabatabaei S, Johansson P, Hansson O, Andreasson U, Månsson JE, Johansson JO, Olsson B, Wallin A, Svensson J, Blennow K, Zetterberg H (2011) Cerebrospinal fluid microglial markers in Alzheimer’s disease: elevated chitotriosidase activity but lack of diagnostic utility. Neuromolecular Med 13:151-159. https://doi.org/10.1007/s12017-011-8147-9. Norden DM, Muccigrosso MM, Godbout JP (2015) Microglial priming and enhanced reactivity to secondary insult in aging, and traumatic CNS injury, andneurodegenerative disease. Neuropharmacology 96:29-41. https://doi.org/10.1016/j.neuropharm.2014.10.028. Olsson B, Hertze J, Ohlsson M, Nägga K, Höglund K, Basun H, Annas P, Lannfelt L, Andreasen N, Minthon L, Zetterberg H, Blennow K, Hansson O (2013) Cerebrospinal fluid levels of heart fatty acid binding protein are elevated prodromally in Alzheimer’s disease and vascular dementia. J Alzheimers Dis 34:673-679. https://doi.org/ 10.3233/JAD-121384. Chiasserini D, Parnetti L, Andreasson U, Zetterberg H, Giannandrea D, Calabresi P, Blennow K (2010 ) CSF levels of heart fatty acid binding protein are altered during early phases of Alzheimer’s disease. J Alzheimer’s Dis 22:1281-1288. https://doi.org/ 10.3233/JAD-2010-101293. Vidal-Piñeiro D, Sørensen Ø, Blennow K, Capogna E, Halaas NB, Idland AV, Mowinckel AM, Pereira JB, Watne LO, Zetterberg H, Walhovd KB, Fjell AM (2022) Relationship between cerebrospinal fluid neurodegeneration biomarkers and temporal brain atrophy in cognitively healthy older adults. Neurobiol Aging 116:80‐91. https://doi.org/ 10.1016/j.neurobiolaging.2022.04.010. Shioda N, Yabuki Y, Kobayashi Y, Onozato M, Owada Y, Fukunaga K ( 2014) FABP3 protein promotes α-synuclein oligomerization associated with 1-Methyl-1,2,3,6-tetrahydropiridine-induced neurotoxicity. J Biol Chem 289, 18957–18965. https://doi.org/10.1074/jbc.M113.527341. Shioda N, Yamamoto Y, Watanabe M, Binas B, Owada Y, Fukunaga K (2010) Heart-Type Fatty Acid Binding Protein Regulates Dopamine D2 Receptor Function in Mouse Brain. J Neurosci 30, 3146–3155. https://doi.org/10.1523/JNEUROSCI.4140-09.2010. Yamamoto Y, Kida H, Kagawa Y, Yasumoto Y, Miyazaki H, Islam A, Ogata M, Yanagawa Y, Mitsushima D, Fukunaga K, Owada Y (2018) FABP3 in the Anterior Cingulate Cortex Modulates the Methylation Status of the Glutamic Acid Decarboxylase 67 Promoter Region. J Neurosci 38, 10411–10423. https://doi.org/ 10.1523/JNEUROSCI.1285-18.2018. Armstrong RA (2019) Risk factors for Alzheimer’s disease. Folia Neuropathol 57:87-105. https://doi.org/10.5114/fn.2019.85929 Vagelatos NT, Eslick GD (2013) Type 2 diabetes as a risk factor for Alzheimer's disease: the confounders, interactions, and neuropathology associated with this relationship. Epidemiol Rev 35:152-160. https://doi.org/10.1093/epirev/mxs012. Mullins RJ, Diehl TC, Chia CW, Kapogiannis D (2017) Insulin resistance as a link between amyloid beta and tau pathologies in Alzheimer's disease. Front Aging Neurosci 9:118. https://doi.org/10.3389/fnagi.2017.00118. Simpson IA, Carruthers A, Vannucci SJ (2007) Supply and demand in cerebral energy metabolism: The role of nutrient transporters. J Cereb Blood Flow Meta 27:1766-1791. https://doi.org/10.1038/sj.jcbfm.9600521. Jacob RJ, Fan X, Evans ML, Dziura J, Sherwin RS (2002) Brain glucose levels are elevated in chronically hyperglycemic diabetic rats: No evidence for protective adaptation by the blood brain barrier. Metabolism 51:1522-1524. https://doi.org/ 10.1053/meta.2002.36347. Tomlinson DR, Gardiner NJ (2008) Glucose neurotoxicity. Nat Rev Neurosci 9:36-45. https://doi.org/10.1038/nrn2294. Li S, Jin M, Zhang D, Yang T, Koeglsperger T, Fu H, Selkoe DJ (2013) Environmental novelty activates beta2‐adrenergic signaling to prevent the impairment of hippocampal LTP by Abeta oligomers. Neuron 77: 929-941. https://doi.org/10.1016/j.neuron.2012.12.040. Vega GL, Weiner MF, Lipton AM, Von Bergmann K, Lutjohann D, Moore C, Svetlik D (2003) Reduction in levels of 24S-hydroxycholesterol by statin treatment in patients with Alzheimer disease. Arch Neurol 60:510-5. https://doi.org/10.1001/archneur.60.4.510. Chakraborty A, de Wit NM, van der Flier WM, de Vries HE (2017) The blood brain barrier in Alzheimer’s disease. Vascul Pharmacol 89:12-18. https://doi.org/10.1016/j.vph.2016.11.008. Razay G, Vreugdenhil A, Wilcock G (2007) The metabolic syndrome and Alzheimer disease. Arch Neurol 64 (1):93-96. https://doi.org/10.1001/archneur.64.1.93. Al-Kuraishy HM, Majid S. Jabir MS, Albuhadily AK, Al-Gareeb AI, Rafeeq MF (2023) The link between metabolic syndrome and Alzheimer disease: A mutual relationship and long rigorous investigation. Ageing Research Reviews 91:102084. https://doi.org/10.1016/j.arr.2023.102084. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4761789","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":338770358,"identity":"8d401a47-8e6a-4d5e-b399-d93eaeec9680","order_by":0,"name":"Gözde Ceylan","email":"","orcid":"","institution":"Istanbul University","correspondingAuthor":false,"prefix":"","firstName":"Gözde","middleName":"","lastName":"Ceylan","suffix":""},{"id":338770359,"identity":"86e9ccb7-b61b-4b07-ad7b-51d7540f97db","order_by":1,"name":"Nazan Karagöz Sakallı","email":"","orcid":"","institution":"Bakırköy Psychiatric Hospital","correspondingAuthor":false,"prefix":"","firstName":"Nazan","middleName":"Karagöz","lastName":"Sakallı","suffix":""},{"id":338770360,"identity":"0184d19e-8e8e-44f2-a9fb-ea4cf5547d72","order_by":2,"name":"Hacer Eroğlu Içli","email":"","orcid":"","institution":"Bakırköy Psychiatric Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hacer","middleName":"Eroğlu","lastName":"Içli","suffix":""},{"id":338770361,"identity":"0009a91a-0ea3-4bdf-b439-c0f715e1b50a","order_by":3,"name":"Canan Başaran Küçükgergin","email":"","orcid":"","institution":"Istanbul University","correspondingAuthor":false,"prefix":"","firstName":"Canan","middleName":"Başaran","lastName":"Küçükgergin","suffix":""},{"id":338770362,"identity":"875b76da-af25-42fd-a4b7-97c83d49f159","order_by":4,"name":"Semra Doğru-Abbasoğlu","email":"","orcid":"","institution":"Istanbul University","correspondingAuthor":false,"prefix":"","firstName":"Semra","middleName":"","lastName":"Doğru-Abbasoğlu","suffix":""},{"id":338770363,"identity":"5c361e3f-3b3a-45a4-a473-d56783804f85","order_by":5,"name":"Pervin Vural","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYLCCBDDJ3PiAgeEASVoYmw2I1wIBjG0SRGkxZ+99JvFwx+HE7e0H26p5au7I8TMwP3x0A48Wy57jZhKJZw4nzjmT2Hab59gzY8kGNmPjHDxaDG6kMRsktqUlzmAAaWE7nLjhAA+bNF4t959BtfA/bCvm+UeMlhtsjA8S22wSZ0gktjHzthGhxbInDazFeIbEw2bJuX2HjSWbCfjFnP0Yw8GfbRKyM/iTD3548+2wHD9788PHeB2GzGHiAZHMeJRjaGH8QUD1KBgFo2AUjEwAAB1ETq+JXHIgAAAAAElFTkSuQmCC","orcid":"","institution":"Istanbul University","correspondingAuthor":true,"prefix":"","firstName":"Pervin","middleName":"","lastName":"Vural","suffix":""}],"badges":[],"createdAt":"2024-07-18 10:17:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4761789/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4761789/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":62729514,"identity":"56a3828f-07d3-4d0f-82b2-4bc4c38b7800","added_by":"auto","created_at":"2024-08-18 23:05:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":778130,"visible":true,"origin":"","legend":"\u003cp\u003eSerum total tau (A), neurofilament light polypeptide (NFL,B), neurogranin (C), chitinase-3-like protein 1 (YKL-40,D) and fatty acid binding protein-3 (FABP-3,E) in controls and mild, moderate and severe AD (Alzheimer’s disease) stages. Kruskal-Wallis and Mann-Whitney \u003cem\u003eU\u003c/em\u003e tests. * p= 0.031; ** p= 0.013; *** p\u0026lt; 0.001; ## p= 0.002; ### p\u0026lt; 0.001\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4761789/v1/76f6f7c0fc0fa26a07d8629d.png"},{"id":62729515,"identity":"fe478bfd-0e3c-4d67-8ce3-2e368016429b","added_by":"auto","created_at":"2024-08-18 23:05:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":249252,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver operating characteristics (ROC) curves for total tau, neurofilament light polypeptide (NFL) and total tau x NFL for the discrimination between AD (Alzheimer’s disease) patients and controls. AUC, area under the curve\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4761789/v1/6ad8cea07217f2f5dc831c15.png"},{"id":62729516,"identity":"059d0c76-6acb-4f32-b928-5cfa7c27ef65","added_by":"auto","created_at":"2024-08-18 23:05:42","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":641018,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation between neurofilament light polypeptide (NFL) – MMSE (Mini-Mental State Examination, A); total tau – CDR-SB (Clinical Dementia Rating Scale-Sum of Boxes, B); NFL – CDR-SB (C); NFL – total tau (D); FABP-3 – age (E)\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4761789/v1/f022109c62dc2a7efaefdab1.png"},{"id":64407201,"identity":"12a85237-b30c-435e-843e-881e829b4e4a","added_by":"auto","created_at":"2024-09-12 18:02:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1798302,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4761789/v1/89ad0cc2-d72e-473c-b74a-24ad6472bae3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Combined Serum Total Tau-Neurofilament Light Polypeptide Could be Used as Screening Biomarkers For Alzheimer’s Disease","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDementia is a worldwide health problem and the fifth-leading cause of death. Alzheimer\u0026rsquo;s disease (AD) is the most common type of dementia, accounting for 50\u0026ndash;75% of all cases. With an increase average lifespan and elderly population AD is expected to become one of the most important health problems in the future. Clinically AD is characterized by progressive memory loss and cognitive decline. Pathologically, AD is characterized by extracellular deposits of β-amyloid (Aβ) plaques, and intracellular neurofibrillary tangles constructed by clusters of hyperphosphorylated tau protein [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Other pathological changes include microglia activation, neuronal degeneration, neuroinflammation, altered protein clearance, lipid metabolism changes, disrupted synaptic function and blood-brain barrier (BBB) integrity [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Previously, most prefered sample on biomarkers of AD was cerebrospinal fluid (CSF).Unfortunately, CSF sampling is an invasive lumbar puncture procedure, having a risk of infection and headaches. Among the other alternative and noninvasive biological samples are peripheral blood and urine. Recently, new candidate markers in noninvasive samples reflecting the underlying AD pathology, are investigating in order to make an early diagnosis. Among these markers, neurofilament light polypeptide (NFL) is the most abundant component of myelinated axons and reflects axonal degeneration [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Neurogranin is a postsynaptic protein playing an important role in synaptic activity and plasticity, and reflects synaptic degeneration [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Chitinase-3-like protein 1 (YKL-40) is a carbohydrate-binding protein secreted by activated macrophages and microglia, and reflects neuroinflammation. Fatty acid binding protein-3 (FABP-3) is important for membrane fluidity, neuronal synapse formation and intracellular lipids transport. FABP-3 indicates lipid metabolism disorder [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn present study, we measured serum total tau, NFL, neurogranin, YKL-40 and FABP-3 levels in mild, moderate and severe stages of AD patients and cognitively healthy controls to evaluate whether these parameters provide information for AD; to evaluate their potential in the early diagnosis and follow-up of AD; to evaluate the relationship between study parameters themselves and with blood glucose and lipid profile in AD.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\"\u003e\n \u003ch2\u003eStudy population and sample collection\u003c/h2\u003e\n \u003cp\u003eEighty six AD patients from the Department of Neurology of Bakirkoy Mental Health and Neurological Disorders Training and Research Hospital, and 30 cognitively normal individualas were included. Characteristics of patients with AD and controls were given in Table\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e. The ages and gender distributions in patient and control groups were comparable. Patients with disease onset before 65 years were classified as early onset AD (n\u0026thinsp;=\u0026thinsp;28), and the remaining patients as late onset AD. Each patient underwent a thorough clinical investigation, including medical history, physical and neurological examination, laboratory screening tests, brain magnetic resonance imaging (MRI) and/or positron emmission tomography (PET). All subjects completed the cognitive tests including Mini-Mental State Examination (MMSE) and Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) scores. Scores lower than 24 for MMSE, and higher than 4 for CDR-SB denotes greater severity of AD. Patients with mild cognitive impairment (MCI) were not included in the study. AD patients were diagnosed according to to the NINCDS-ADRDA criteria [\u003cspan\u003e3\u003c/span\u003e]. The exclusion criteria were: a history of neuropsychiatric disease other than AD, metabolic disorders, potential causes of cognitive decline, such as cerebral infarction, subdural hematomas, hydrocephalus, intracranial tumors and infections, alcohol and other substances abuse. This study was approved by the Local Ethics Committee at Istanbul Faculty of Medicine (18.01.2023\u0026ndash;1582983). Blood samples were taken after written informed consents were obtained from subjects or their next-of-kin. Fasting venous blood samples were collected, centrifuged within 20\u0026ndash;60 minutes at 2500 rpm for 15 min, aliquoted, and stored at -80\u003csup\u003e⸰\u003c/sup\u003eC until use. Glucose and lipid profile parameters were measured by autoanalyzer (Roche Cobas C6000 Switzerland).\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Characteristics of patients with AD and controls, mean (range)\u003c/p\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003eAD (n= 86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003eControl (n= 30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e- value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e71.73 (48-91)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e72.63 \u0026nbsp;(62-87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.377\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Male, n (%)\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Female, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e37 (43)\u003c/p\u003e\n \u003cp\u003e49 (57)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e15 (50)\u003c/p\u003e\n \u003cp\u003e15 (50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.518\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eDisease onset\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026lt; 65 years n (%) \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026gt; 65 year, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e28 (32.5)\u003c/p\u003e\n \u003cp\u003e58 (67.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eFamily history, \u003cem\u003en\u003c/em\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e39 (45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eClinical dementia staging scale\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Mild, n (%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Moderate, n (%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Severe, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e33 (38.4)\u003c/p\u003e\n \u003cp\u003e29 (33.7)\u003c/p\u003e\n \u003cp\u003e24 (27.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eMMSE\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e13.76 (0-24)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eCDR-SB\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e11.31 (4-18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eGlucose (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e120.29 (78 - 267)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e100.34 (68 - 140)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eTotal cholesterol (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e206.10 (96.2 - 292.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e174 (101.3 - 243.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eTriglyceride (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e151.04(48.3 - 437)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e114.65 (50.7 -255.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.055\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eLDL- cholesterol (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e126.96 (35 - 190)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e103.36 (46 - 172)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eHDL-\u0026nbsp;cholesterol (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e50.63 (32.3 - 141.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e54.52 (26.5 - 86.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.258\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eTotal tau (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e208.97 (20.2 - 679.62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e48.33 (6.98 - 117.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eNFL (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e3.67 (0.11 - 13.23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e1.66 (0.32 - 7.08)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eNeurogranin (ng/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e232.83 (58.01- 688.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e216.17 (70 - 635.96)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.605\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eYKL-40 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e56441.1\u003c/p\u003e\n \u003cp\u003e(21094.22 - 93599.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e64927.34\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(19262.78 - 173242.26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.354\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.663974151857836%\" valign=\"top\"\u003e\n \u003cp\u003eFABP-3 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e2552.41\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(1065.63 - 6182.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.463651050080774%\" valign=\"top\"\u003e\n \u003cp\u003e2459.9\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(717.75 - 6285.03)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.408723747980615%\" valign=\"top\"\u003e\n \u003cp\u003e0.212\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eMann-Whitney \u003cem\u003eU\u003c/em\u003e test\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eAbbreviations:\u003c/em\u003e AD, Alzheimer\u0026rsquo;s disease; MMSE, Mini-Mental State Examination; \u0026nbsp;CDR-SB, Clinical Dementia Rating Scale-Sum of Boxes; \u0026nbsp;NFL, \u0026nbsp;neurofilament light polypeptide; \u0026nbsp; \u0026nbsp; YKL-40, chitinase-3-like protein 1; FABP-3, fatty acid binding protein-3\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\"\u003e\n \u003ch2\u003eDetermining serum total tau, NFL, neurogranin, YKL-40, and FABP-3 levels\u003c/h2\u003e\n \u003cp\u003eFor measuring of serum total tau, NFL, neurogranin, YKL-40, and FABP-3 ELISA (enzyme-linked immunosorbent assay) test kits were used (TAU, Elabscience E-EL-H0948; NFL, Elabscience E-EL-H0741, Houston, Texas, USA; neurogranin, Mybiosource MBS167225, San Diego, CA, USA; YKL-40, Invitrogen BMS2322, Waltham, MA, USA and FABP-3, Invitrogen BMS2263, Waltham, MA, USA).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\"\u003e\n \u003ch2\u003eStatistical analysis\u003c/h2\u003e\n \u003cp\u003eStatistical analyses were performed with IBM SPSS Statistics 21.0 package program (IBM Corp. SPSS Inc, Chicago, IL, USA) and GraphPad Prism (10, GraphPad Software, La Jolla, CA, ABD). Data distribution and homogeneity were evaluated with the Kolmogorov-Smirnov and Levene tests. ANOVA was used to compare normally and homogenously distributed data. Kruskall-Wallis and Mann-Whitney \u003cem\u003eU\u003c/em\u003e tests were used to compare not-normally and non-homogeneously distributed data. Gender distribution in the study and control groups was analyzed with the chi-square test. The correlation of continuous variables was analyzed by Spearman\u0026rsquo;s rank correlation analysis. Receiver operating characteristic curve (ROC) analysis was used to evaluate the ability of biomarkers to discriminate between Alzheimer\u0026apos;s patients and control groups. For biomarkers with ROC analysis resulted in an area under the curve (AUC)\u0026thinsp;\u0026gt;\u0026thinsp;0.6 cutoff value, sensitivity, and specificity were calculated. Probability values (p) smaller than 0.05 were regarded as statistically significant.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eCharacteristics of patients with AD and controls were given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. AD patients had higher serum glucose, total cholesterol and LDL values than in the controls (p\u0026thinsp;=\u0026thinsp;0.022, p\u0026thinsp;=\u0026thinsp;0.004, p\u0026thinsp;=\u0026thinsp;0.005, respectively). As we espected, there were correlations between glucose and lipid profile parameters (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and p\u0026thinsp;=\u0026thinsp;0.030, data not shown). MMSE scores were gradualy decreased and CDR-SB increased in mild, moderate and severe AD stages (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, data not shown). MMSE scores and FABP-3 levels were increased, and CDR-SB decreased in late onset AD when compared with early oncet AD (p\u0026thinsp;=\u0026thinsp;0.004, p\u0026thinsp;=\u0026thinsp;0.010, and p\u0026thinsp;=\u0026thinsp;0.049 respectively, Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) and fatty acid binding protein-3 (FABP-3) in early and late onset Alzheimer\u0026rsquo;s Disease (AD)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEarly onset AD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLate onset AD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMMSE (mean (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.96 (0\u0026ndash;24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15.10 (0\u0026ndash;24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCDR-SB (mean (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.71 (5\u0026ndash;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.64 (4\u0026ndash;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.049\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFABP-3 (pg/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2096.09\u003c/p\u003e \u003cp\u003e(1065.63 -4603.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2773.19\u003c/p\u003e \u003cp\u003e(1126.0-6182.49)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.010\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eMann-Whitney \u003cem\u003eU\u003c/em\u003e test\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eSerum total tau (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and NFL (p\u0026thinsp;=\u0026thinsp;0.002) were higher, and neurogranin, YKL-40, and FABP-3 unchanged in Alzheimer\u0026rsquo;s patients compared to the controls (Figule 1A,B,C,D,E). Total tau levels in all AD subgroups were found to be higher compared to the controls (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Additionally, total tau levels in severe stage were increased according to both mild and moderate stage patients (p\u0026thinsp;=\u0026thinsp;0.013, p\u0026thinsp;=\u0026thinsp;0.031, respectively; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWhile serum NFL levels were higher in the moderate and severe stage subgroups compared to controls (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), there was no change in the mild stage AD. Significant increase was also observed between severe and mild stage AD (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and between modetrate and mild stage (p\u0026thinsp;=\u0026thinsp;0.002) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003eIn addition, to test the suitability of total tau and NFL as biomarkers for the diagnosis of AD, ROC curves were drawn. When the cut-off point for total tau was selected as 71.5 pg/mL, sensitivity was found to be 79.1% and specificity was 76.7% (AUC: 0.865, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Regarding to NFL ROC curve, when the cut-off point for NFL was selected as 1.835 pg/mL, sensitivity was found to be 66.3% and specificity was 66.7% (AUC: 0.693, p\u0026thinsp;=\u0026thinsp;0.002). Combining of total tau and NFL resulted in AUC to be 0.848 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSerum NFL levels were negatively correlated with MMSE score (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). Total tau and NFL levels showed a positive relationship with CDR-SB (p\u0026thinsp;=\u0026thinsp;0.017, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, respectively, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB,C). There was a positive correlation between total tau and NFL levels (p\u0026thinsp;=\u0026thinsp;0.002; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD). FABP-3 levels were significantly correlated with age (p\u0026thinsp;=\u0026thinsp;0.006; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eE). Additionally, both NFL and total tau were in close relationship with lipid profile parameters (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCorrelations between serum total tau, neurofilament light polypeptide (NFL) levels with total cholesterol, triglyceride and low density lipoprotein (LDL) cholesterol levels\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal tau\u003c/p\u003e \u003cp\u003e(r, \u003cem\u003ep\u003c/em\u003e value)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNFL\u003c/p\u003e \u003cp\u003e(r, \u003cem\u003ep\u003c/em\u003e value)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal cholesterol\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.299 (0.001) *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.247 (0.008) *\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTriglyceride\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.210 (0.024) *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.196 (0.035) *\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLDL cholesterol\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.287 (0.002) *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.199 (0.032) *\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003cem\u003eSpearman correlation test\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe aim of this study was to evaluate the relationship between the serum tau, NFL, neurogranin, YKL-40, FABP-3 concentrations and cognitive decline as well as the diagnostic performance of these candidate biomarkers in AD. We found that: a) serum total tau and NFL were higher, neurogranin, and YKL-40 were not changed in AD; b) both serum total tau and NFL levels showed a positive relationship with CDR-SB; c) serum total tau values alone had the highest sensitivity and specificity as diagnostic biomarker; d) when NFL and total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone; e) FABP-3 concenrations were similar in AD and controls, but patients with late onset disease had increased FABP-3 when compared to early onset; f) serum glucose, total cholesterol, and LDL levels were elevated in AD patients; g) NFL was correlated with total tau, and both NFL and total tau were correlated with lipid profile parameters.\u003c/p\u003e \u003cp\u003eAD is a neurodegenerative disease representing a significant public health problem with an increasing incidence. Laboratory medicine supports clinicians in the convenient follow-up of AD. The general aim is to recovery the patients\u0026rsquo; quality of life with diminish economic costs. Noteworthily, most biomarkers are assesed in the CSF - an prefered biological sample reflecting the neuropathological alterations. However, obtaining CSF is challenging procedure due to its invasive nature and needs highly skilled staff to perform it. Blood collection is much less invasive than lumbar puncture and is performed routinely. Therefore, using serum/plasma for assesment of biomarkers has numerous advantages.\u003c/p\u003e \u003cp\u003eAmong the main characteristics of AD are tau and Aβ pathologies [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Because tau pathology is more correlated with clinical and cognitive decline than Aβ pathology [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] we preferred to measure total tau levels in peripheral blood. Tau protein is important for the structural integrity of the neuronal cytoskeleton and axonal transport. The increased abnormal posttanslational phosphorylation of tau protein leads to altered binding to microtubules, polymerization into insoluble double-stranded neurofilaments, forming intraneuronal tangles, and subsequently resulting in neuronal death. Both phosphorylated and total tau are secreted into CSF and peripheral blood. Many studies showed that there is a correlation between total tau concentration in peripheral blood and brain tissue total tau levels evaluated by PET scan [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In our study, increased serum total tau concentrations in AD patients were found. Moreower, there was a gradualy increase of serum total tau from mild to severe AD stage. Our findings are in line with studies reporting increasing total tau levels in Alzheimer's patients [\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and differs from other two studies reporting no clear relationship between serum total tau and AD [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Because total tau concentrations in peripheral blood reflects axonal degeneration and neuronal death, it can also be considered as a measure of cognitive decline [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Therefore, serum total tau measurement may be useful not only for the early diagnosis of AD, but also for monitoring the dynamic process of neurodegeneration during the progression of the disease. We observed that with the determined cut-off value, 79.1% sensitivity, 76.7% specificity and 0.865 AUC value, serum total tau is a valuable parameter in discriminating between healthy individuals and Alzheimer's patients. Our findings are in line with many studies on the same subject [\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the spectrum of AD pathologies neurofilaments are molecules reflecting axonal degeneration and providing prognostic information. Neurofilaments are critical for the growth and stability of axons. NFL is the smallest unit among neurofilaments consisting of light, medium, heavy chain, α-internexin and peripherin. In various neurodegenerative, vascular, traumatic and inflammatory diseases NFL is secreted in high amounts into CSF ​​and plasma. Although plasma NFL are 50 times lower than in CSF, it has been shown that CSF and plasma concentrations are well correlated [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In our study, NFL levels were higher in the AD group compared to the control group. When evaluated according to the clinical dementia score, there were significant increases from the mild stage to the severe stage. However, no significant difference was detected between the control group and mild-stage AD. Accordingly, NFL seems to be a suitable parameter for follow-up rather than early diagnosis of the disease and may be associated with the progression of cognitive decline. Similar to our findings, various studies reporting increased NFL levels in AD linked to brain hypometabolism, brain atrophy and cognitive decline [\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In addition, it is seen from the results that both tau and NFL were correlated with clinical dementia score reflecting cognitive decline. The combined use of NFL and total tau can increase the accuracy of diagnosis of the disease with an AUC value of 0.848. A similar correlation were found Mattsson et al. in their study [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIt is well known that the number of synapses correlates with the degree of cognitive disturbances, and synapse loss seen in AD is the strongest pathological finding correlated with cognitive decline [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. So, we decided to measure serum neurogranin levels as marker reflecting synaptic degeneration, but no significant change was detected. Elevated CSF neurogranin levels in patients with AD and mild cognitive impairment compared to controls have been reported previously [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Additionally, it have been shown that neurogranin 48\u0026ndash;76 peptide was domminant in CSF and brain tissue, but was not found in plasma [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Because neurogranin is cleaved enzymatically it can be expected that neurogranin in brain tissue, CSF and peripheral blood has different lenghts fragments. Another reason for the different results may be the different sample matrix used in our study.\u003c/p\u003e \u003cp\u003eNeuroinflammation is a common feature of AD pathology, and many epidemiological studies have demonstrated a reduction in the risk and progression of AD after long-term administration of nonsteroidal anti-inflammatory drugs [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. YKL-40 is a marker for microglia differentiation and activation, and is considered as indicator of inflammation. Elevated CSF levels of YKL-40 have been found in various infectious and non-infectious disorders of the CNS. It has also been shown that CSF concentrations of YKL-40 are high in AD, but there are also conflicting data [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. In our study, although YKL-40 levels showed an increasing patern, especially in patients with severe dementia, this increase was not statistically significant. The increasing patern may suggest that the inflammatory process and pro-inflammatory signals are more prominent in patients with severe dementia. Excessive inflammation and microglial activation cause exacerbation of neurodegeneration, impairment of synaptic plasticity and cognitive decline [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. However, in our study, no correlation was found between YKL-40 and clinical dementia score. The most serious limitation of the use of YKL-40 as a marker appears to be its nonspecificity. Comorbidities such as inflammatory and neoplastic diseases, which are very common in the elderly population, may lead to an increase in YKL-40 concentrations. Therefore, when using YKL-40 as a diagnostic test, it will be necessary to take an in-depth medical history regarding comorbidities and medications used to avoid misinterpretation of biomarker levels.\u003c/p\u003e \u003cp\u003eFABP-3 is a biomarker reflecting neuronal membrane damage associated with lipid metabolism, and the usability of this parameter for the diagnosis of AD is being investigated. FABP-3 was isolated from heart muscle, and have widespread tissue distribution. Clinically, FABP-3 can be used as an additional marker in serum after acute myocardial infarction. Many studies have suggested that CSF levels of FABP-3, may have diagnostic importance in the early stages of AD [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. It has been reported that high CSF FABP-3 levels positively correlate with brain Aβ burden in the early stage and are associated with brain atrophy in individuals with Aβ pathology [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. In contrast, Vidal-Pinerio et al. [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] showed that FAPB-3 levels in CSF predicted brain atrophy in cognitively healthy elderly individuals, independent of amyloidopathy and tauopathy biomarkers. According to these results, it is thought that all measured FABP-3 levels originate from the brain and not from the serum. However, we did not observe any difference in serum FABP-3 levels between groups in our study. This may be due to the fact that the sample we used was serum instead of CSF or that the people in the control group had additional diseases such as cardiovascular disease. It is seen from the results that in late-onset AD FABP-3 concentrations were higher than in early-onset AD. We can doubt that increase of the serum FABP-3 levels in late-onset AD might be a part of the disintegration of lipids and fatty acids in the brain of elderly patients [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. We suggest that elevated FABP-3 may reflect age-related changes rather than AD pathology. The presence of significant correlation between FABP-3 and age supports this observation.\u003c/p\u003e \u003cp\u003eRecently, many studies have been shown that disorders such as diabetes mellitus, obesity, hypercholesterolemia, or hypertension, play a pivotal role in the development of AD [\u003cspan additionalcitationids=\"CR34\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Indeed, in our study, serum glucose, total cholesterol and LDL levels were found to be higher in the AD group than in the control group. The brain's glucose requiremend is provided by insulin-independent glucose transporters (GLUT-1, GLUT-3) [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. The increased blood glucose causes abnormally high glucose transfer to neurons and triggers gluconeurotoxicity [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Glucose exerts neurotoxic effects through various mechanisms, including the polyol pathway, formation of advanced glycation end products (AGE), and activation of MAP kinases [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. There are studies reporting that high AGE levels induce Aβ accumulation in the brain and are associated with cognitive decline in Alzheimer's patients [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOn the other hand, even subtle changes in lipid metabolism cause profound effects on cognitive functions. The human brain produces approximately 30% of the cholesterol in the body. Cholesterol is important for maintaining the structural integrity of the plasma membrane for neurons and astrocytes and regulation of membrane fluidity. Cholesterol is also critical for formation of myelin sheaths that provide insulation around axons and increasing the spreading speed of electrical signals throughout the nervous system. Demyelination is used as a biomarker for dementia pathology. Moreover, cholesterol is a component of lipid rafts implicating in signal transduction, cell-cell adhesion, and lipid/protein separation. Therefore, while cholesterol metabolism plays an important role in maintaining brain function, cholesterol dysregulation acts as a potential risk factor for many diseases, including AD. Another link between cholesterol and AD is 24-hydroxycholesterol - the oxidation product of cholesterol occuring only in the brain. This oxysterol can pass through the blood brain barrier. Increased plasma level of 24-hydroxycholesterol in AD probably reflects neuronal death and disordered membrane cholesterol turnover [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. On the other hand, high LDL levels induce vascular changes similar to the atherosclertic inflammatory lesions and cause blood-brain barrier permeability impairement [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Tau and Aβ patologies in patients with metabolic syndrome were observed [42,43 ]. Since AD shares many biochemical features of ins\u0026uuml;lin resistance and metabolic syndrome, high serum glucose, total cholesterol and LDL cholesterol levels in AD patients found in our study is not surprising. Moreover, the presense of strong correlations between both serum tau and NFL lipid profile parameters strengthen the hypothesis that dyslipidemia probably is also predisposing factor to AD.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study showed increased serum total tau and NFL levels in AD. We evaluated for the first time the combined effects of serum total tau and NFL as biomarkers in early diagnosis of AD, and assessed whether the created ROC curves had a strengthening effect on the parameters. It was observed that serum total tau values alone had the highest sensitivity and specificity. Moreover, when NFL and total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone. In addition, NFL was significantly correlated to total tau. The strong correlations between both tau and NFL with lipid profile parameters in AD support the relationship between AD and metabolic syndrome. Lifestyle changes such as dietary modifications and increased phisical activity even though cannot prevent AD, may have a positive effect on the disease course by causing a decrease in modifiable risk factors.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement\u0026nbsp;\u003c/strong\u003eThis work was supported by the Research Fund of Istanbul University (Project No. TTU-2023-39857).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e Conceptualization: PV, SDA; Methodology: GC, CBK; Sample collection: NKS, HEI, GC; Formal analysis: GC, CBK; Data analysis: PV, GC; Writing-original draft: PV; Writing - review \u0026amp; editing: PV, SDA.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e No datasets were generated or analysed during the current study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u0026nbsp;\u003c/strong\u003eThis study was approved by the Local Ethics Committee at Istanbul Faculty of Medicine (18.01.2023-1582983).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisclosure statement\u0026nbsp;\u003c/strong\u003eNo potential conflict of interest was reported by the authors.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKatzman R, Saitoh T (1991) Advances in Alzheimer\u0026rsquo;s disease. FASEB J 5:278-286.\u003c/li\u003e\n\u003cli\u003ePark SA, Han SM, Kim CE (2020) New fluid biomarkers tracking non-amyloid-\u0026beta; and non-tau pathology in Alzheimer\u0026apos;s disease. Exp Mol Med 52:556-568. https://doi.org/10.1038/s12276-020-0418-9.\u003c/li\u003e\n\u003cli\u003eMcKhan G, Drachman DFolstein M, Katzman R, Price D, Stadlan EM (1984) Clinical diagnosis of Alzheimer\u0026rsquo;s disease: report of the NINCDS-ADRA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer\u0026rsquo;s Disease. Neurology 34:938-944. https://doi.org/10.1212/wnl.34.7.939.\u003c/li\u003e\n\u003cli\u003ePais M, Martinez L, Ribeiro O, Loureiro\u003csup\u003e \u003c/sup\u003eJ, Fernandez\u003csup\u003e \u003c/sup\u003eR, Valiengo L, Canineu P, Stella\u003csup\u003e \u003c/sup\u003eF, Talib L , Radanovic\u003csup\u003e \u003c/sup\u003eM, Forlenza\u003csup\u003e \u003c/sup\u003e\u003csup\u003e \u003c/sup\u003eOV (2020) Early diagnosis and treatment of Alzheimer\u0026rsquo;s disease: new definitions and challenges. Braz J Psychiatry 42:431-441. https://doi.org/10.1590/1516-4446-2019-0735.\u003c/li\u003e\n\u003cli\u003eMielke MM, Hagen CE, Xu J, Chai X, Vemuri P, Lowe VJ, Airey DC, Knopman DS, Roberts RO, Machulda MM, Jack CR Jr\u003csup\u003e \u003c/sup\u003e, Petersen\u003csup\u003e \u003c/sup\u003e RC, Jeffrey L Dage JL (2018) Plasma phospho-tau181 increases with Alzheimer\u0026rsquo;s disease clinical severity and is associated with tau- and amyloid-positron emission tomography. Alzheimers Dement\u003cem\u003e \u003c/em\u003e14:989-997. https://doi.org/10.1016/j.jalz.2018.02.013. \u003c/li\u003e\n\u003cli\u003ePark JC, Han SH, Yi D, Byun MS, Lee JH, Jang S, Ko K, Jeon SY, Lee YS, Kim YK, Lee\u003csup\u003e \u003c/sup\u003eDY, Mook-Jung\u003csup\u003e \u003c/sup\u003eI (2019) Plasma tau/amyloid-\u0026beta;1-42 ratio predicts brain tau deposition and neurodegeneration in Alzheimer\u0026rsquo;s disease. Brain 142:771-786. https://doi.org/10.1093/brain/awy347.\u003c/li\u003e\n\u003cli\u003eTsai CL, Liang CS, Lee JT, Su MW, Lin CC, Chu HT, Tsai\u003csup\u003e \u003c/sup\u003eCK, Lin GY\u003csup\u003e \u003c/sup\u003e, Lin\u003csup\u003e \u003c/sup\u003eYK, Yang\u003csup\u003e \u003c/sup\u003e FC (2019) Associations between plasma biomarkers and cognition in patients with Alzheimer\u0026apos;s disease and amnestic mild cognitive impairment: a cross-sectional and longitudinal study. J Clin Med 8:1893. https://doi.org/doi: 10.3390/jcm8111893.\u003c/li\u003e\n\u003cli\u003eJiang T, Gong PY, Tan MS, Xue X, Huang S, Zhou JS, Tan\u003csup\u003e \u003c/sup\u003e L, Zhang\u003csup\u003e \u003c/sup\u003eYD (2019) Soluble TREM1 concentrations are increased and positively correlated with total tau levels in the plasma of patients with Alzheimer\u0026apos;s disease. Aging Clin Exp Res 31:1801-1805. https://doi.org/10.1007/s40520-019-01122-9.\u003c/li\u003e\n\u003cli\u003eDage JL, Wennberg AMV, Airey DC, Hagen CE, Knopman DS, Machulda MM, Roberts RO, Jack CR Jr, Petersen RC, Mielke MM (2016) Levels of tau protein in plasma are associated with neurodegeneration and cognitive function in a population-based elderly cohort. Alzheimers Dement 12: 1226-1234. https://doi.org/10.1016/j.jalz.2016.06.001.\u003c/li\u003e\n\u003cli\u003ePase MP, Beiser AS, Himali JJ, Satizabal CL, Aparicio HJ, DeCarli C, Ch\u0026ecirc;ne G, Dufouil C, Seshadri S (2019) Assessment of plasma total tau level as a predictive biomarker for dementia and related endophenotypes. JAMA Neurol 76:598-606. https://doi.org/10.1001/jamaneurol.2018.4666.\u003c/li\u003e\n\u003cli\u003eVerberk IMW, Slot RE, Verfaillie SCJ, Heijst H, Prins ND, van Berckel BNM, Scheltens P, Teunissen CE, van der Flier WM (2018) Plasma amyloid as prescreener for the earliest alzheimer pathological changes. \u003cem\u003eAnn Neurol\u003c/em\u003e 84:648-658. https://doi.org/ 10.1002/ana.25334.\u003c/li\u003e\n\u003cli\u003eDe Wolf F, Ghanbari M, Licher S, McRae-McKee K, Gras L, Weverling GJ, Wermeling P, Sedaghat S, Ikram MK, Waziry R, Koudstaal W, Klap J, Kostense S, Hofman A, Anderson R, Goudsmit J, Ikram MA (2020) Plasma tau, neurofilament light chain and amyloid-\u0026beta; levels and risk of dementia; a population-based cohort study. \u003cem\u003eBrain\u003c/em\u003e 143:1220-1232. https://doi.org/10.1093/brain/awaa054.\u003c/li\u003e\n\u003cli\u003eChiu MJ, Chen YF, Chen TF, Yang SY, Yang FP, Tseng TW, Chieh JJ, Chen JC, Tzen KY, Hua MS, Horng HE (2014) Plasma tau as a window to the brain-negative associations with brain volume and memory function in mild cognitive impairment and early Alzheimer\u0026rsquo;s disease. Hum Brain Mapp 35:3132-3142. https://doi.org/10.1002/hbm.22390.\u003c/li\u003e\n\u003cli\u003ePreische O, Schultz SA, Apel A, Kuhle J, Kaeser SA, Barro C, Gr\u0026auml;ber S, Kuder-Buletta E, LaFougere C, Laske C, V\u0026ouml;glein J, Levin J, Masters CL, Martins R, Schofield PR, Rossor MN, Graff-Radford NR, Salloway S, Ghetti B, Ringman JM, Noble JM, Chhatwal J, Goate AM, Benzinger TLS, Morris JC, Bateman RJ, Wang G, Fagan AM, McDade EM, Gordon BA, Jucker M (2019) Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer\u0026rsquo;s disease. Nat Med. 25:277-283. https://doi.org/10.1038/s41591-018-0304-3.\u003c/li\u003e\n\u003cli\u003eMattsson N, Andreasson U, Zetterberg H, Blennow K (2017) Association of plasma neurofilament light with neurodegeneration in patients with Alzheimer disease. JAMA Neurol 74:557-566. https://doi.org/10.1001/jamaneurol.2016.6117.\u003c/li\u003e\n\u003cli\u003eZetterberg H (2016) Neurofilament light: a dynamic cross-disease fluid biomarker for neurodegeneration. Neuron 91:1-3. https://doi.org/10.1016/j.neuron.2016.06.030.\u003c/li\u003e\n\u003cli\u003eLewczuk P, Ermann N, Andreasson U, Schultheis C, Podhorna J, Spitzer P, Maler JM, Kornhuber J, Blennow K, Zetterberg H (2018) Plasma neurofilament light as a potential biomarker of neurodegeneration in Alzheimer\u0026rsquo;s disease. Alzheimers Res Ther 10:71. https://doi.org/10.1186/s13195-018-0404-9.\u003c/li\u003e\n\u003cli\u003eScheff SW, Price DA, Schmitt FA, DeKosky ST, Mufson EJ (2007) Synaptic alterations in CA1 in mild Alzheimer disease and mild cognitive impairment. Neurology\u003cem\u003e \u003c/em\u003e68:1501-8. https://doi.org/10.1212/01.wnl.0000260698.46517.8f.\u003c/li\u003e\n\u003cli\u003eTerry RD, Masliah E, Salmon DP, Butters N, DeTeresa R, Hill R, Hansen LA, Katzman R (1991) Physical basis of cognitive alterations in Alzheimer\u0026rsquo;s disease: synapse loss is the major correlate of cognitive impairment. Ann Neurol\u003cem\u003e \u003c/em\u003e30:572-80. https://doi.org/10.1002/ana.410300410.\u003c/li\u003e\n\u003cli\u003eMavroudis IA, Petridis F, Chatzikonstantinou S, Kazis D (2020) A meta-analysis on CSF neurogranin levels for the diagnosis of Alzheimer\u0026apos;s disease and mild cognitive impairment. Aging Clin Ex Res 32:1639-1646. https://doi.org/ 10.1007/s40520-019-01326-z.\u003c/li\u003e\n\u003cli\u003eWang L (2019 Association of cerebrospinal fluid Neurogranin with Alzheimer\u0026apos;s disease. Aging Clin Ex Res 31:185-189 https://doi.org/ 10.1007/s40520-018-0948-3. \u003c/li\u003e\n\u003cli\u003eHellwig K, Kvartsberg H, Portelius E, Andreasson U, Oberstein TJ, Lewczuk P, Blennow K, Kornhuber J, Maler JM, Zetterberg H, Spitzer P (2015) Neurogranin and YKL-40: independent markers of synaptic degeneration and neuroinflammation in Alzheimer\u0026apos;s disease. Alzheimers Res Ther 7:74. https://doi.org/10.1186/s13195-015-0161-y. \u003c/li\u003e\n\u003cli\u003eMcGeer PL, McGeer EG (2013) The amyloid cascade-inflammatory hypothesis of Alzheimer disease: implications for therapy. Acta Neuropathol\u003cem\u003e \u003c/em\u003e126: 479 -497. https://doi.org/10.1007/s00401-013-1177-7.\u003c/li\u003e\n\u003cli\u003eOlsson B, Hertze J, Lautner R, Zetterberg H, N\u0026auml;gga K, H\u0026ouml;glund K, Basun H, Annas P, Lannfelt L, Andreasen N, Minthon L, Blennow K, Hansson O (2013) Microglial markers are elevated in the prodromal phase of Alzheimer\u0026rsquo;s disease and vascular dementia. J Alzheimers Dis\u003cem\u003e \u003c/em\u003e33:45-53. https://doi.org/10.3233/JAD-2012-120787.\u003c/li\u003e\n\u003cli\u003eMattsson N, Tabatabaei S, Johansson P, Hansson O, Andreasson U, M\u0026aring;nsson JE, Johansson JO, Olsson B, Wallin A, Svensson J, Blennow K, Zetterberg H (2011) Cerebrospinal fluid microglial markers in Alzheimer\u0026rsquo;s disease: elevated chitotriosidase activity but lack of diagnostic utility. Neuromolecular Med\u003cem\u003e \u003c/em\u003e13:151-159. https://doi.org/10.1007/s12017-011-8147-9. \u003c/li\u003e\n\u003cli\u003eNorden DM, Muccigrosso MM, Godbout JP (2015) Microglial priming and enhanced reactivity to secondary insult in aging, and traumatic CNS injury, andneurodegenerative disease. Neuropharmacology\u003cem\u003e \u003c/em\u003e96:29-41. https://doi.org/10.1016/j.neuropharm.2014.10.028.\u003c/li\u003e\n\u003cli\u003eOlsson B, Hertze J, Ohlsson M, N\u0026auml;gga K, H\u0026ouml;glund K, Basun H, Annas P, Lannfelt L, Andreasen N, Minthon L, Zetterberg H, Blennow K, Hansson O (2013) Cerebrospinal fluid levels of heart fatty acid binding protein are elevated prodromally in Alzheimer\u0026rsquo;s disease and vascular dementia. J Alzheimers Dis 34:673-679. https://doi.org/ 10.3233/JAD-121384.\u003c/li\u003e\n\u003cli\u003eChiasserini D, Parnetti L, Andreasson U, Zetterberg H, Giannandrea D, Calabresi P, Blennow K (2010 ) CSF levels of heart fatty acid binding protein are altered during early phases of Alzheimer\u0026rsquo;s disease. J Alzheimer\u0026rsquo;s Dis\u003cem\u003e \u003c/em\u003e22:1281-1288. https://doi.org/ 10.3233/JAD-2010-101293. \u003c/li\u003e\n\u003cli\u003eVidal-Pi\u0026ntilde;eiro D, S\u0026oslash;rensen \u0026Oslash;, Blennow K, Capogna E, Halaas NB, Idland AV, Mowinckel AM, Pereira JB, Watne LO, Zetterberg H, Walhovd KB, Fjell AM (2022) Relationship between cerebrospinal fluid neurodegeneration biomarkers and temporal brain atrophy in cognitively healthy older adults. Neurobiol Aging 116:80‐91. https://doi.org/ 10.1016/j.neurobiolaging.2022.04.010.\u003c/li\u003e\n\u003cli\u003eShioda N, Yabuki Y, Kobayashi Y, Onozato M, Owada Y, Fukunaga K ( 2014) FABP3 protein promotes \u0026alpha;-synuclein oligomerization associated with 1-Methyl-1,2,3,6-tetrahydropiridine-induced neurotoxicity. J Biol Chem 289, 18957\u0026ndash;18965. https://doi.org/10.1074/jbc.M113.527341.\u003c/li\u003e\n\u003cli\u003eShioda N, Yamamoto Y, Watanabe M, Binas B, Owada Y, Fukunaga K (2010) Heart-Type Fatty Acid Binding Protein Regulates Dopamine D2 Receptor Function in Mouse Brain. J Neurosci 30, 3146\u0026ndash;3155. https://doi.org/10.1523/JNEUROSCI.4140-09.2010.\u003c/li\u003e\n\u003cli\u003eYamamoto Y, Kida H, Kagawa Y, Yasumoto Y, Miyazaki H, Islam A, Ogata M, Yanagawa Y, Mitsushima D, Fukunaga K, Owada Y (2018) FABP3 in the Anterior Cingulate Cortex Modulates the Methylation Status of the Glutamic Acid Decarboxylase 67 Promoter Region. J Neurosci 38, 10411\u0026ndash;10423. https://doi.org/ 10.1523/JNEUROSCI.1285-18.2018.\u003c/li\u003e\n\u003cli\u003eArmstrong RA (2019) Risk factors for Alzheimer\u0026rsquo;s disease. Folia Neuropathol 57:87-105. https://doi.org/10.5114/fn.2019.85929\u003c/li\u003e\n\u003cli\u003eVagelatos NT, Eslick GD (2013) Type 2 diabetes as a risk factor for Alzheimer\u0026apos;s disease: the confounders, interactions, and neuropathology associated with this relationship. Epidemiol Rev 35:152-160. https://doi.org/10.1093/epirev/mxs012.\u003c/li\u003e\n\u003cli\u003eMullins RJ, Diehl TC, Chia CW, Kapogiannis D (2017) Insulin resistance as a link between amyloid beta and tau pathologies in Alzheimer\u0026apos;s disease. Front Aging Neurosci 9:118. https://doi.org/10.3389/fnagi.2017.00118.\u003c/li\u003e\n\u003cli\u003eSimpson IA, Carruthers A, Vannucci SJ (2007) Supply and demand in cerebral energy metabolism: The role of nutrient transporters. J Cereb Blood Flow Meta 27:1766-1791. https://doi.org/10.1038/sj.jcbfm.9600521.\u003c/li\u003e\n\u003cli\u003eJacob RJ, Fan X, Evans ML, Dziura J, Sherwin RS (2002) Brain glucose levels are elevated in chronically hyperglycemic diabetic rats: No evidence for protective adaptation by the blood brain barrier. Metabolism\u003cem\u003e \u003c/em\u003e51:1522-1524. https://doi.org/ 10.1053/meta.2002.36347.\u003c/li\u003e\n\u003cli\u003eTomlinson DR, Gardiner NJ (2008) Glucose neurotoxicity. Nat Rev Neurosci 9:36-45. https://doi.org/10.1038/nrn2294.\u003c/li\u003e\n\u003cli\u003eLi S, Jin M, Zhang D, Yang T, Koeglsperger T, Fu H, Selkoe DJ (2013) Environmental novelty activates beta2‐adrenergic signaling to prevent the impairment of hippocampal LTP by Abeta oligomers. Neuron 77: 929-941. https://doi.org/10.1016/j.neuron.2012.12.040.\u003c/li\u003e\n\u003cli\u003eVega GL, Weiner MF, Lipton AM, Von Bergmann K, Lutjohann D, Moore C, Svetlik D (2003) Reduction in levels of 24S-hydroxycholesterol by statin treatment in patients with Alzheimer disease. Arch Neurol\u003cem\u003e \u003c/em\u003e 60:510-5. https://doi.org/10.1001/archneur.60.4.510.\u003c/li\u003e\n\u003cli\u003eChakraborty A, de Wit NM, van der Flier WM, de Vries HE (2017) The blood brain barrier in Alzheimer\u0026rsquo;s disease. Vascul Pharmacol\u003cem\u003e \u003c/em\u003e89:12-18. https://doi.org/10.1016/j.vph.2016.11.008.\u003c/li\u003e\n\u003cli\u003eRazay G, Vreugdenhil A, Wilcock G (2007) The metabolic syndrome and Alzheimer disease. Arch Neurol 64 (1):93-96. https://doi.org/10.1001/archneur.64.1.93.\u003c/li\u003e\n\u003cli\u003eAl-Kuraishy HM, Majid S. Jabir MS, Albuhadily AK, Al-Gareeb AI, Rafeeq MF (2023) The link between metabolic syndrome and Alzheimer disease: A mutual relationship and long rigorous investigation. Ageing Research Reviews 91:102084. https://doi.org/10.1016/j.arr.2023.102084.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Alzheimer’s disease, blood biomarkers, early diagnosis","lastPublishedDoi":"10.21203/rs.3.rs-4761789/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4761789/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eAim\u003c/h2\u003e \u003cp\u003eTo evaluate the relationship between Alzheimer\u0026rsquo;s disease (AD) with serum tau, neurofilament light polypeptide (NFL), neurogranin, chitinase-3-like protein 1 (YKL-40) and fatty acid binding protein-3 (FABP-3) as non-invasive markers for early diagnosis of AD.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eTotal 86 AD patients and 30 healthy individuals were recruited. Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) scores, glucose and lipid profile parameters were assessed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAD patients were divided into three groups according to CDR: 33 mild, 29 moderate, and 24 severe stages. Serum total tau and NFL levels were higher, neurogranin, YKL-40, FABP-3 not changed in AD patients. Late onset AD was related with higher FABP-3 levels when compared to early onset. Glucose, total cholesterol, LDL were elevated in AD patients. We evaluated for the first time the combined effects of serum total tau-NFL as biomarkers in early diagnosis of AD, and assessed whether the created ROC curves had a strengthening effect on the parameters. Serum total tau values alone had the highest sensitivity and specificity. When NFL-total tau were combined, NFL sensitivity and specificity was higher compared to the values obtained alone. In addition, NFL was correlated to total tau. Both NFL and total tau were in close relationship with lipid profile parameters.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eOur findings suggest that serum total tau alone is sufficient for the early diagnosis of AD; however, combinations of total tau-NFL biomarkers could also be used as screening tests. High glucose, total cholesterol, LDL support the relationship between AD and metabolic syndrome.\u003c/p\u003e","manuscriptTitle":"Combined Serum Total Tau-Neurofilament Light Polypeptide Could be Used as Screening Biomarkers For Alzheimer’s Disease","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-18 23:05:37","doi":"10.21203/rs.3.rs-4761789/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fec72ba8-4b7d-43c1-9dd7-33f58bd28f04","owner":[],"postedDate":"August 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-09-12T17:54:00+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-18 23:05:37","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4761789","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4761789","identity":"rs-4761789","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}