Association between with Serum neurofilament light and neurochemistry deficits in patients with spinocerebellar ataxia type 3

Association between with Serum neurofilament light and neurochemistry deficits in patients with spinocerebellar ataxia type 3 | 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 Association between with Serum neurofilament light and neurochemistry deficits in patients with spinocerebellar ataxia type 3 Yuchao Chen, Yi Jin, Zhouyao Hu, Mengqiu Qiu, Dan Li, Qiusi Cai, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2132253/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Jan, 2023 Read the published version in The Cerebellum → Version 1 posted 7 You are reading this latest preprint version Abstract Extensive evidence supports the claim that serum neurofilament light chain (sNfL) can be used as a biomarker for monitoring disease severity in patients with spinocerebellar ataxia type 3 (SCA3). However, little is known about the associations between sNfL levels and neurochemical alterations in SCA3 patients. Serum samples were collected from ATXN3 mutation carriers ( n = 20) and normal controls ( n = 14). sNfL levels, measured by a single-molecule array, were compared between SCA3 patients and controls. We explored the relationship between sNfL levels and metabolic changes via magnetic resonance spectroscopy (MRS) scans. sNfL levels in SCA3 patients were higher than those in healthy controls, and these levels were correlated with disease severity. Associations emerged between the elevation of sNfL levels and lower brain metabolite changes, reflected as N-acetyl aspartate/creatine (NAA/Cr). These associations remained significant after multiple comparison corrections. Our results confirmed that serum sNfL levels are increased in SCA3 and are correlated with cerebellar hemisphere metabolic changes. Brain metabolic changes and sNfL levels show promise as potential complementary biomarkers for clinical trials for patients with SCA3. Serum neurofilament light sNfL NAA/Cr SCA3 Figures Figure 1 Figure 2 Figure 3 Introduction Spinocerebellar ataxia type 3 (SCA3) is the most frequent autosomal dominant ataxia worldwide, and it is caused by an abnormal CAG expansion at exon 10 of the ATXN3 gene [ 1 ]. The number of CAG trinucleotide repeats in ATXN3 ranges from 12 to 44, whereas at least one expanded allele ranging between 52 and 87 CAG repeats is defined as an expanded repeat [ 2 ]. SCA3 is a disease characterized clear clinical heterogeneity. It mainly involves progressive cerebellar ataxia, pyramidal signs, and extrapyramidal syndrome. Non-characteristic manifestations, such as spastic paraplegia phenotypes, cognitive, psychiatric disturbances, and sleep disorders, have also been observed [ 3 ]. the expansion of CAG repeats in the ATXN3 gene can express the abnormal folding protein, which leads to selective neuronal cell death along with neurochemical alterations that can be visualized using magnetic resonance spectroscopy (MRS), including decreases in acetylcholine and N-acetyl aspartate (NAA) [ 4 – 6 ]. NAA has long been used as a marker of neuronal integrity and viability, and it is one of the most important brain metabolites determined by proton MRS [ 7 , 8 ]. MRS can reveal early metabolic/cellular changes in various spinocerebellar ataxia types (SCAs), likely to occur before cerebellar signs are obvious, and even before brain atrophy. This indicates that the measurement of neurochemical changes in brain tissue by MRS may be superior to clinical observation in specific circumstances [ 4 ]. Although promising drugs for ATXN3 expansion have emerged in preclinical studies, biomarkers for evaluating their efficacy have not been adequately assessed in humans. Disease-modifying therapies advancing toward clinical trials include antisense oligonucleotides (ASOs) that target ATXN3 RNA transcripts, reducing the expression of abnormal proteins in SCA3 animal models and patient-derived cell models [ 9 – 11 ]. However, in parallel with the rapid development of these potential therapeutics, biomarkers that measure target engagement, disease onset, and disease progression must be established for clinical trials to be successful. Previous studies suggest that serum neurofilament light chain (sNfL) is a promising marker of target engagement in SCA3, which is detectable in the presymptomatic and symptomatic SCA3 cohort [ 12 – 15 ]. sNfL levels and cerebellar metabolites of NAA/Cr ratios have been found to be biomarkers of neuro-axonal damage in SCA3/MJD patients, but the relationship between them is still unclear. Therefore, this study was performed to assess whether there is a significant association between cerebellar NAA/Cr values and indicators of neurodegeneration, as reflected by sNfL levels. Methods Subjects This study was approved by the Ethics Committee of the Affiliated Hospital of Hangzhou Normal University. Informed consent was obtained from all subjects before participation in the study. In our study, 20 unrelated patients with genetically confirmed SCA3 and 14 healthy controls were recruited consecutively between March 2020 and May 2022 from the Department of Neurology in the Affiliated Hospital of Hangzhou Normal University. These normal participants were matched for age and sex at the group level. Serum samples were obtained from 20 patients with ataxia features caused by the ATXN3 repeat expansion and 14 normal individuals. The Scale for the Assessment and Rating of Ataxia (SARA) and the International Cooperative Ataxia Rating Scale (ICARS) were used to measure the severity of ataxia symptoms at the time of serum collection. Proton Magnetic Resonance Spectroscopy (H-mrs) All participants underwent identical MR procedures using a Siemens 1.5T magnetic resonance imaging (MRI) scanner. 1 H-MRS measurements were then performed to determine the value of N-acetyl aspartate (NAA)/creatine (Cr), and choline complex (Cho)/Cr in local cerebellar metabolites [ 16 ]. The multiple-voxel 1 H-MRS sequence was acquired with the following parameters: repetition time (TR) = 4,280 ms, echo time (TE) = 135 ms, and voxel size = 6.3 mm × 6.3 mm × 15 mm. We selected the target as the cerebellum, which includes the bilateral cerebellar hemispheres, the dentate nucleus, and the cerebellar vermis, in sequence by voxel. The local cerebellar metabolites consisted of the values of NAA/Cr and Cho/Cr, as detected via a proton MR wave. Snfl Levels (Dup: Abstract ?) Serum samples were taken from all participants and collected according to standardized local procedures. Then, the serum samples were aliquoted and immediately stored at -80°C. sNfL concentrations were detected using a single-molecule (Simoa) array method and then quantified on the Simoa HD-1 Analyzer platform (GBIO, Hangzhou, China), using a Simoa NF-light Advantage Kit (Quanterix, Massachusetts, USA) [ 17 ]. All sNfL concentrations were within the linear ranges of this assay. Statistical Analysis Statistical analyses were performed using SPSS 25.0 for Mac (Armonk, NY), and graphs were drafted with GraphPad Prism 7 (La Jolla, CA). Test statistics were considered significant at p < 0.05 (two-tailed). The data for numerical variables were described as the mean (standard deviation) if normally distributed or median (interquartile range) if non-normally distributed. We tested the normality of variables using the Shapiro–Wilk test, and we tested the homogeneity of variances using the Levene test. For variables in line with the assumptions of normality and homogeneity of variances, the groups were compared with a t -test with Bonferroni correction for further multiple comparisons, if applicable. For variables not in line with the assumptions of normality, the groups were compared using a nonparametric Mann–Whitney U test, with Bonferroni correction for further multiple comparisons, if applicable. Correlation analyses were performed to investigate the relationships between the sNfL level and cerebellar metabolite changes, including in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere. Specifically, cerebellar metabolite changes were fitted with the individual sNfL level as a covariate while adjusting for the effects of age and intracranial volume on the relationship between the sNfL and GM volume. Then, correction for multiple comparisons at the cluster level at p < 0.05 was used to perform the correlation analyses between the sNfL and the cerebellar metabolite changes. Results Demographic and Clinical Data In total, this study included 20 SCA3 patients and 14 healthy controls. Table 1 summarizes the sociodemographic, clinical, and biomarker characteristics of all participants. No significant differences in age or gender were observed between the SCA3 patients and the controls ( p > 0.05). The median age for serum collection in patients with SCA3 was 39.2 years; the median age at disease onset was 32.5 years, but this age varied widely (23–64 years). The median CAG repeat length of the SCA3 patients was 74.6. The median SARA and ICARS scores for all SCA3 carriers were 12.54 and 34.35, respectively. The sNfL concentrations were 4.76 times higher in the 20 ATXN3 mutation carriers than they were in age-matched healthy controls. Table 1 Demographic, clinical, and biochemical characteristics of controls and SCA3 patients. Characteristic Health Control (mean ± SD) SCA3 (mean ± SD) P -value Number 14 20 n/a Gender, Male: Female 10: 4 14: 6 0.928 a Age at serum collection (years) 34.64 ± 7.72 39.20 ± 11.22 0.198 b Age at onset (years) n/a 32.5 ± 10.46 n/a Duration of disease (years) n/a 6.7 ± 2.11 n/a CAG repeat length n/a 74.6 ± 4.98 n/a SARA 0 12.54 ± 4.64 < 0.001 ICARS 0 34.35 ± 12.31 < 0.001 posture and gait 0 14.15 ± 6.69 < 0.001 limb kinetic function 0 14.90 ± 6.263 < 0.001 speech disorders 0 2.75 ± 1.25 < 0.001 oculomotor disorders 0 2.55 ± 1.36 < 0.001 Serum NfL, pg/mL 7.43 ± 2.79 35.33 ± 9.01 < 0.001 MRS available, n 14 20 n/a SARA, the Scale for the Assessment and Rating of Ataxia; ICARS, the International Cooperative Ataxia Rating Scale; NfL, neurofilament light chain; MRS, magnetic resonance spectroscopy; n/a, not available. a, Chi-squared test; b, dependent samples t-test. Brain Metabolite Levels With available MRS results, we found that the values of the NAA/Cr and NAA/Cho ratios were significantly reduced in the dentate nucleus and cerebellar vermis in the ATXN3 expansion carriers compared with that in the normal controls ( p < 0.001, dentate nucleus; p < 0.001, cerebellar vermis), whereas only the NAA/Cr ratio was significantly decreased in the cerebellar cortex ( p 0.05; Fig. 1 ; Supplemental Table 1 ). In addition, no significant differences in the NAA/Cr, Cho/Cr, or NAA/Cho ratio were observed in the three ROIs of the left and right cerebellum ( p > 0.05). In all SCA3 carriers, the total SARA and ICARS scores negatively correlated with the NAA/Cr ratio (dentate nucleus: r = − 689, p < 0.001; cerebellar vermis: r = − 0.553, p < 0.011; cerebellar hemisphere: r = − 0.493, p < 0.027), but they did not correlate with the NAA/Cho ratio in the three ROIs. Likewise, similarly negative correlation results were identified in the three ROIs between the total ICARS scores with the NAA/Cr ratio (dentate nucleus: r = − 691, p < 0.001; cerebellar vermis: r = − 0.537, p < 0.015; cerebellar hemisphere: r = − 0.486, p < 0.03), and the ICARS scores did not correlate with the NAA/Cho ratio in the three ROIs. In addition, the Cho/Cr ratios in the dentate nucleus and cerebellar vermis did not correlate with the total SARA and ICARS scores; however, they did negatively correlate with these scores in the cerebellar hemisphere (SARA: r = − 0.576, p < 0.008, ICARS: r = − 0.506, p < 0.023). To confirm the robustness of the primary findings, After the analysis of Bonferroni’s corrected p -value ( p < 0.016) was performed, the NAA/Cr values in the dentate nucleus and cerebellar vermis were still negatively correlated with the SARA and ICARS scores, whereas the NAA/Cr values in the cerebellar hemisphere did not correlate with the SARA or ICARS scores. The Cho/Cr ratio in the cerebellar hemisphere was also still negatively correlated with the SARA and ICARS scores after the Bonferroni test. No significant associations were found between the values of the NAA/Cr and NAA/Cho ratios and age at disease onset, disease duration, or CAG repeats in patients with SCA3 ( p > 0.05). Snfl Levels At the time of serum collection, the ATXN3 expansion carriers had higher NfL levels (median: 35.33 pg/mL) compared with the healthy controls (median: 7.43 pg/mL, p = 0.001; Table 1 ). This observation was still statistically significant upon correction for age (post hoc Bonferroni-corrected p = 0.04). In participants with SCA3, the NfL levels were not associated with age at serum collection, age at onset, disease duration, or CAG repeats, but they were negatively correlated with the SARA and ICARS scores (SARA: r = 0.472, p < 0.036; ICARS: r = 0.465, p < 0.039). sNfL did not correlate with posture and gait, limb kinetic function and or oculomotor disorders in any subgroup of ICARS scores, but it was significantly correlated with speech disorders ( r = 0.620, p < 0.004). We also used age as a covariate because of its general association with sNfL levels. Statistical values demonstrated the significant correction between the NfL concentration and the SARA and ICARS scores in the SCA3 patients but not the subgroups of ICARS scores. Associations Of Nfl Levels With Brain Metabolite Levels In all SCA3 patients, higher sNfL levels were associated with lower cerebellar hemisphere, cerebellar vermis, and dentate nucleus NAA/Cr and NAA/Cho levels; however, the latter two ROIs did not survive multiple comparisons correction. Higher NfL levels were correlated with lower NAA/Cr ratios in the dentate nucleus (DN), cerebellar vermis (CV), and cerebellar hemisphere (CH) (DN: r = − 0.502, p < 0.024; CV: r = − 0.486, p < 0.013; CH: r = − 572, p < 0.008). Higher NfL values did not correlate with the levels of NAA/Cho in the dentate nucleus (DN: r = -0.358, p < 0.122), but negatively correlated with the NAA/Cho in the cerebellar vermis and cerebellar hemisphere (CV: r = -0.582, p < 0.007; CH: r = -0.656, p < 0.002; Fig. 2 ). No significant correlations between the Cho/Cr ratio in the three ROIs and NfL emerged. Age was used as a covariate to remove variance, which correlated in the sNfL levels and brain metabolite levels. Upon correction for age (post hoc Bonferroni corrected p = 0.016), higher NfL levels were significantly associated with lower NAA/Cho levels in the cerebellar hemisphere and cerebellar vermis. Moreover, NfL levels correlated with lower NAA/Cr levels in the cerebellar hemisphere, whereas they showed no significant correlation in the cerebellar vermis region; and no significant association was found between NfL levels and the NAA/Cr and NAA/Cho ratios in SCA3 patient at Bonferroni-corrected p = 0.016 and the normal controls (Table 2 ). Table 2 Associations between neurochemistry of the 1H-MRS scan and NfL in the SCA3 patients. Regions of interest Metabolic ratios NfL Controls SCA3 patients Dentate nucleus NAA/Cr r 0.091 -0.502 P 0.648 0.024 a Cho/Cr r 0.087 -0.193 P 0.662 0.414 b NAA/Cho r 0.042 -0.358 P 0.836 0.122 b Cerebellar vermis NAA/Cr r 0.116 -0.486 P 0.411 0.03 b Cho/Cr r 0.058 0.013 P 0.776 0.956 b NAA/Cho r 0.175 -0.582 P 0.378 0.007 b * Cerebellar cortex NAA/Cr r 0.048 -0.572 P 0.813 0.008 b * Cho/Cr r 0.090 -0.03 P 0.663 0.901 b NAA/Cho r -0.091 -0.656 P 0.652 0.002 b * Associations between Serum NfL concentrations and neurochemistry of the 1HMRS images in controls and SCA3 patients, by means of linear regression. P-values below 0.05 are bolded. NfL, neurofilament light chain; NAA, N-acetyl-aspartate; Cho, choline-containing compounds; Cr, creatine and phosphocreatine. a, spearman tests; b, Pearson test. *Significant after correction for multiple testing (Bonferroni corrected P-value: P < 0.016, three tests). Discussion In the current study, sNfL and cerebellar metabolite levels were determined in a cohort of 20 SCA3 patients to examine associations between the two measures. Compared with controls, we found high NfL levels and lower cerebellar metabolite levels, including NAA/Cr and NAA/Cho ratios, in 20 ATXN3 expansion carriers. Both measures—cerebellar metabolite and NfL levels—correlated with greater disease severity in our patients with SCA3. In addition, elevated NfL levels were associated with lower cerebellar metabolite levels; especially, low levels in NAA/Cr values are known to indicate cerebellar degeneration in ATXN3 repeat expansion carriers. As such, sNfL levels and cerebellar metabolites capture abnormalities in SCA3 patients, and thus, they may serve as complementary biomarkers for disease detection and future treatment monitoring. In SCA3 disease, polyQ-expanded ATXN3 leads to protein neurotoxicity and causes selective neuronal cell death along with metabolic/cellular changes detected by MRS, including decreases in acetylcholine and NAA [ 5 ]. Emerging evidence has shown early neurochemical alterations in patients with SCA3 in the preclinical stage, even before brain atrophy [ 18 ]. In this regard, the measure of the NAA/Cr ratios has been found to be a good neuroimaging biomarker and can be used to monitor the clinical progression of SCA3 [ 4 , 19 ]. In the current study, our findings demonstrated a decrease of the NAA/Cr and NAA/Cho ratios in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere, suggesting that the degree of neuronal dysfunction in SCA3 would be consistent with previous findings [ 5 , 20 ]. Associations between ataxia severity and metabolic/cellular changes have been described as reflected by NAA/Cr ratios. Our findings also showed that ICARS scores were negatively correlated with NAA/Cr ratios in the three ROIs of the dentate nucleus, cerebellar vermis, and cerebellar hemisphere in 20 SCA3 patients, which is in line with previous results [ 5 , 21 ]. Furthermore, we found that SARA scores had an inverse relationship with NAA/Cr ratios in these ROIs. These results further confirmed that the metabolic alterations of the cerebellum were correlated to the predominant clinical features in SCA3 patients and suggested that NAA is a good marker for SCA3 [ 4 , 5 ]. Neurofilament light protein can be released in significant quantities following neuro-axonal damage or neurodegeneration. The elevation of sNfL is considered a biomarker of clinical disease severity in SCA3 [ 12 , 22 , 23 ]. Higher NfL levels are not only correlated with ataxia symptoms and non-ataxia signs in ataxic SCA3 patients, but they show similar correlations in preclinical SCA3 individuals [ 13 , 23 ]. Our findings were consistent with a previously published study on SCA3, which also found that NfL was elevated in patients with SCA3 and that NfL levels correlated with ataxia symptoms [ 13 ]. This correlation between elevated NfL levels and clinical severity could persist after accounting for the potential confounder of age. In our patients with SCA3, both higher sNfL levels and decreased metabolites in the cerebellum significantly correlated with clinical severity, as reflected by the ICARS scores. Therefore, we hypothesized that the elevation of NfL values may be correlated with a lower cerebellar NAA/Cr ratio. Our study also explored the association between NfL and MRI features in a subgroup of ataxic SCA3 patients. First, our ROI analysis showed that certain cerebellar regions with a lower NAA/Cr ratio tended to be significantly associated with higher NfL levels, which included regions in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere. Furthermore, higher NfL levels also showed an association with a reduced NAA/Cho ratio in the cerebellar vermis and cerebellar hemisphere, but a similar association was not found in the dentate nucleus in our analyses. Third, unexpectedly, there was no significant relationship between increased NfL and the Cho/Cr ratio in the cerebellum. One potential explanation for this result is that the Cho/Cr ratio was not observed to decrease in our patients. This finding suggests that the elevation of NfL was mainly associated with neuronal dysfunction rather than cell membrane or neurotransmitter metabolism impairment in our SCA3 patients, likely indicating the subtle impairment of neurofilaments in the cerebellum. Regarding these findings, further studies are needed to explore the association between the NAA/Cr ratio and sNfL in SCA3. Both higher NfL levels and decreased cerebellar metabolites have been suggested to reflect neuronal dysfunction not only in SCA3 but also in other degenerative diseases [ 24 – 27 ]. In our samples, we found both measures—NAA/Cr ratios and sNfL levels—to be significant predictors of clinical severity, reflected as ICARS scores. However, it is difficult to estimate the relevance of sNfL levels because changes in these levels may possibly result from shifts of NAA/Cr, NAA/Cho, or both metabolites simultaneously. In this study, a mediation model based on a multiple regression approach helped us clarify how prominent the contribution of each component was. As the limited statistical power did not allow us to test a model with two mediators (NAA/Cr and NAA/Cho), we used two separate models with either the NAA/Cr ratio or NAA/Cho ratio as the mediator; the results indicated that in our patients with SCA3, the prediction of clinical severity by NfL was more likely to be driven by changes in the NAA/Cr ratio (Table 3 ; Fig. 3 ) but not changes in the NAA/Cho ratio ( Supplemental Table 2; Supplemental Fig. 1 ). sNfL levels and cerebellar metabolites of NAA/Cr ratio are both the biomarkers of neuro-axonal damage in patients with SCA3. The serum NfL levels often reflect the neuron damage in the whole brain, while NAA/Cr ratio reflects the damage in part of the cerebellum in SCA3, which may explain why NAA/Cr ratio acts as a mediator. Considering the limited sample size and possible VOI localizations detected by MRS scanning, methods based on multiple regression analysis appear to improve our understanding of the cerebellar metabolic process in the SCA3 cohorts above conventional analysis of variance; they also provide more evidence of the putative mechanism by allowing testing of specific mechanistic models. Table 3 Summary of Model Coefficients: Effect of serum NfL on clinical severity Mediated by NAA/Cr ratio Moderated Model 1a NAA/Cr ratios F(2) = 4.9733, p = 0.0199*, R 2 = 0.3691 coef SE t p NfL a -0.0155 0.0053 -2.9471 0.009 age f -0.0045 0.0042 -1.0620 0.3031 Constant 1.6538 0.2501 6.6126 < 0.001 Model 1b ICARS scores F(3) = 8.8199, p = 0.0011**, R 2 = 0.632 coef SE t p NfL c' 0.2232 0.2578 0.8656 0.3995 NAA/Cr b -25.7773 9.6889 -2.6605 0.0171 age g 0.422 0.1738 2.4273 0.0274 Constant 33.9433 18.8833 1.7975 0.0911 Direct effect NfL-ICARS coef SE t p 0.2232 0.2578 0.8656 0.3995 Indirect effect NfL-NAA/Cr-ICARS coef BootSE BootLLCI BootULCI 0.3989 0.2538 0.0291 0.9927 Several potential limitations restrict the interpretability of our findings. First, the limited sample size was not sufficient to draw an affirmative conclusion in our cohort; thus, the findings need to be further validated in a larger cohort. Second, information on asymptomatic SCA3 patients was not available, which makes it difficult to analyze the correlation between cerebellar metabolites and sNfL levels. Third, not only should the neurochemical values of NAA, Cho, and Cr be included, but Gln, Glu, and Tau should also be determined; doing this could help to further explore the correction with sNfL in future research. Finally, while the mediated moderation analysis in our present study provides evidence for an associated effect, we need to acknowledge that effects were only significant for ICARS (but not SARA) scores and need to be replicated in future research. In summary, we used a multimodal approach combining the serum biomarker with cerebellar metabolites to investigate the association between NfL and indicators of neurodegeneration in 20 SCA3 patients. To the best of our knowledge, this is the first study to examine correlated NfL levels with the cerebellar metabolites reflected by the NAA/Cr ratio in ATXN3 mutation carriers. Our results confirmed that sNfL levels are increased in SCA3 and that they are correlated with clinical disease severity, reflected as ICARS and SARA scores, as well as brain metabolic changes. We demonstrated that the NfL level and cerebellar metabolites were promising complementary biomarkers that capture the effects of the expansion ATXN3 mutation. In addition, our multiple regression models revealed that the decrease in the NAA/Cr ratio mediated this prediction effect. Additional longitudinal studies are strongly warranted to build on these results in the future. Declarations Acknowledgments The local medical ethics committee of the affiliated hospital of Hangzhou normal university approved the study and written informed consent was obtained from all participants. Competing interests The authors report no potential conflicts of interest. Availability of data and materials Data available upon request to the authors. Author Contributions Y.C. Chen designed the work. Y.C. Chen, Y. Jin, Z.Y. Hu, M.Q. Qiu, D. Li, Q.S. Cai, C.J. Tao, D.N. Lou, L. Qi, S.D. Chen, H. Yu, Z.M. Gao initiated the project. Y.C. Chen, Y. Jin, Z.Y. Hu, M.Q. Qiu, D. Li, Q.S. Cai, C.J. Tao, D.N. Lou, L. Qi, S.D. Chen, H. Yu, Z.M. Gao collected and analyzed the data. Y.C. Chen wrote the manuscript. H. Yu, Z.M. Gao commented and revised on the manuscript. Y.C. Chen supervised all aspects of the project. All authors read and approved the final manuscript. Funding This work was supported by the grants, 2021KY898 (YCC) and 2021YN2021099 (YCC), from the Medical and Health Science and Technology Project of Zhejiang Province, and Youth cultivation foundation of Affiliated Hospital of Hangzhou Normal University. ORCID Yuchao Chen https://orcid.org/0000-0002-0255-060X Yi Jin https://orcid.org/0000-0001-9989-3934 Zhouyao Hu https://orcid.org/0000-0003-2579-4508 Mengqiu Qiu https://orcid.org/0000-0002-5299-9747 Dan Li https://orcid.org/0000-0003-1987-8852 References Kawaguchi Y, Okamoto T, Taniwaki M, Aizawa M, Inoue M, et al. CAG expansions in a novel gene for Machado-Joseph disease at chromosome 14q32.1. Nature genetics. 1994; 8:221-8. Maciel P, Gaspar C, DeStefano AL, Silveira I, Coutinho P, et al. Correlation between CAG repeat length and clinical features in Machado-Joseph disease. Am J Hum Genet. 1995; 57:54-61. Yuan X, Ou R, Hou Y, Chen X, Cao B, et al. Extra-Cerebellar Signs and Non-motor Features in Chinese Patients With Spinocerebellar Ataxia Type 3. Frontiers in neurology. 2019; 10:110. doi 10.3389/fneur.2019.00110. Wang P-S, Chen H-C, Wu H-M, Lirng J-F, Wu Y-T and Soong B-W. 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PloS one. 2012; 7:e47925. doi 10.1371/journal.pone.0047925. Coarelli G, Darios F, Petit E, Dorgham K, Adanyeguh I, et al. Plasma neurofilament light chain predicts cerebellar atrophy and clinical progression in spinocerebellar ataxia. Neurobiol Dis. 2021; 153:105311. doi 10.1016/j.nbd.2021.105311. Wilke C, Haas E, Reetz K, Faber J, Garcia-Moreno H, et al. Neurofilaments in spinocerebellar ataxia type 3: blood biomarkers at the preataxic and ataxic stage in humans and mice. EMBO Mol Med. 2020; 12:e11803. doi 10.15252/emmm.201911803. Illán-Gala I, Lleo A, Karydas A, Staffaroni AM, Zetterberg H, et al. Plasma Tau and Neurofilament Light in Frontotemporal Lobar Degeneration and Alzheimer Disease. Neurology. 2021; 96:e671-e83. doi 10.1212/WNL.0000000000011226. van der Ende EL, Meeter LH, Poos JM, Panman JL, Jiskoot LC, et al. Serum neurofilament light chain in genetic frontotemporal dementia: a longitudinal, multicentre cohort study. Lancet Neurol. 2019; 18:1103-11. doi 10.1016/S1474-4422(19)30354-0. Elahi FM, Casaletto KB, La Joie R, Walters SM, Harvey D, et al. Plasma biomarkers of astrocytic and neuronal dysfunction in early- and late-onset Alzheimer's disease. Alzheimers Dement. 2020; 16:681-95. doi 10.1016/j.jalz.2019.09.004. Aamodt WW, Waligorska T, Shen J, Tropea TF, Siderowf A, et al. Neurofilament Light Chain as a Biomarker for Cognitive Decline in Parkinson Disease. Movement disorders : official journal of the Movement Disorder Society. 2021; 36:2945-50. doi 10.1002/mds.28779. Additional Declarations No competing interests reported. Supplementary Files Figurelegends.docx Supplementalfigure1.tiff Supplementaltable1.docx Supplementaltable2.docx Cite Share Download PDF Status: Published Journal Publication published 04 Jan, 2023 Read the published version in The Cerebellum → Version 1 posted Editorial decision: Major revision 24 Oct, 2022 Reviews received at journal 17 Oct, 2022 Reviewers agreed at journal 17 Oct, 2022 Reviewers invited by journal 17 Oct, 2022 Editor assigned by journal 12 Oct, 2022 Submission checks completed at journal 11 Oct, 2022 First submitted to journal 04 Oct, 2022 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. 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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-2132253","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":143317545,"identity":"869ce188-9e63-454c-9470-9a1aa3a3ac0f","order_by":0,"name":"Yuchao Chen","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yuchao","middleName":"","lastName":"Chen","suffix":""},{"id":143317546,"identity":"ce080cee-1ffd-4916-b2c0-a600ad450da3","order_by":1,"name":"Yi Jin","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yi","middleName":"","lastName":"Jin","suffix":""},{"id":143317547,"identity":"aa30ff2e-05e8-49b8-82ff-85fd1dfd67d5","order_by":2,"name":"Zhouyao Hu","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zhouyao","middleName":"","lastName":"Hu","suffix":""},{"id":143317548,"identity":"8d41ac93-ed20-4845-94e5-76f2720d2970","order_by":3,"name":"Mengqiu Qiu","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mengqiu","middleName":"","lastName":"Qiu","suffix":""},{"id":143317549,"identity":"c1caca58-73bf-4b25-9ba5-4ab43cf22c80","order_by":4,"name":"Dan Li","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Li","suffix":""},{"id":143317550,"identity":"9863bd0e-8f08-4c5b-94fc-61c4159fc76a","order_by":5,"name":"Qiusi Cai","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Qiusi","middleName":"","lastName":"Cai","suffix":""},{"id":143317551,"identity":"23fdbfda-1021-4830-97fd-a96e7350ff24","order_by":6,"name":"Chenjuan Tao","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Chenjuan","middleName":"","lastName":"Tao","suffix":""},{"id":143317552,"identity":"62af6629-4fc4-4b73-8c48-855c0090737a","order_by":7,"name":"Danning Lou","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Danning","middleName":"","lastName":"Lou","suffix":""},{"id":143317558,"identity":"919ebed2-0d64-4d23-a706-59cd53dd1deb","order_by":8,"name":"Le Qi","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Le","middleName":"","lastName":"Qi","suffix":""},{"id":143317563,"identity":"b78e7c83-9a2b-4efa-89ff-68999fe3f2b9","order_by":9,"name":"Sidan Chen","email":"","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sidan","middleName":"","lastName":"Chen","suffix":""},{"id":143317567,"identity":"b38378ea-98ec-49be-a9b9-ff08a3c635b5","order_by":10,"name":"Hao Yu","email":"","orcid":"","institution":"Zhejiang University School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Yu","suffix":""},{"id":143317568,"identity":"3bc0f8a5-3222-4306-b15a-21a3c1726ea6","order_by":11,"name":"Zhongming Gao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYJAC4z8GNjz87I2NDz8Qq6WApyBNRrLncLOxBLFaPvB8OGxjcCO9TYCHGOXy7ocPbpAwOMwjOfNhG4MEg52cbgMBLYZn0pINDAzSefilE9seFDAkG5sdIKSlIcfMIMHAmkdydmK7gQTDgcRtBLX0vzH/ccCAmcfg5sE2CR5itMhL5BgYNhg48xjcYCRSi4HEswRjBoM0HsmeRGAgGxDhF/n+5APGDH9s7PnZjz98+KHCTo6gFgNUBQYElINtaSBC0SgYBaNgFIxwAACvD0FfsIHHAQAAAABJRU5ErkJggg==","orcid":"","institution":"The Affiliated Hospital of Hangzhou Normal University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Zhongming","middleName":"","lastName":"Gao","suffix":""}],"badges":[],"createdAt":"2022-10-04 14:44:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2132253/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2132253/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12311-022-01507-z","type":"published","date":"2023-01-04T18:13:46+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":27782557,"identity":"fe30df3f-9119-4c90-8dc1-4d9750903af0","added_by":"auto","created_at":"2022-10-14 14:42:30","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":731746,"visible":true,"origin":"","legend":"\u003cp\u003eBrain metabolite levels of the 1HMRS images in the controls and patient group. (A-C) the values of NAA/Cr ratios were significantly reduced in the cerebellar cortex, cerebellar vermis and dentate nucleus in the ATXN3 expansion carriers compared with that in the normal controls. (D-E) the values of the Cho/Cr ratio in the three ROIs did not differ between SCA3 patients and normal controls. (G) the values of the NAA/Cho ratio in the cerebellar cortex did not differ between SCA3 patients and normal controls. (H-I) the values of the NAA/Cho ratio were significantly reduced in the cerebellar vermis and dentate nucleus in the ATXN3 expansion carriers compared with that in the normal controls.P-values from the independent samples t-test（A-B, D-I）and Mann–Whitney U tests（C）are displayed as follows: *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ns: not significant. Acronyms: NAA - N-acetyl aspartate; Cr - creatine; Cho - choline complex; NC - normal controls; SCA3 - Spinocerebellar ataxia type 3 patients.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/64bcef0dfe8ed483f86968e6.png"},{"id":27782891,"identity":"ef0cd98f-d0c8-429b-bbc2-a9597654483b","added_by":"auto","created_at":"2022-10-14 14:47:30","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":796336,"visible":true,"origin":"","legend":"\u003cp\u003eAssociations of NfL levels with brain metabolite levels. (A-C) Higher NfL levels were correlated with lower NAA/Cr ratios in the cerebellar cortex, dentate nucleus and cerebellar vermis. (D-F) No significant correlations between the Cho/Cr ratio in the three ROIs and NfL emerged. (G-H) Higher NfL levels were correlated with lower NAA/Cho ratios in the cerebellar cortex and cerebellar vermis. (I) Higher NfL values did not correlate with the levels of NAA/Cho in the dentate nucleus. Acronyms: NAA - N-acetyl aspartate; Cr - creatine; Cho - choline complex; sNfL - serum neurofilament light chain; NC - normal controls; SCA3 - Spinocerebellar ataxia type 3 patients.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/f20ee02f3d6f3204fad54e77.png"},{"id":27782559,"identity":"55d73303-81ae-41d7-bfc6-183fe2183ab0","added_by":"auto","created_at":"2022-10-14 14:42:30","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":92460,"visible":true,"origin":"","legend":"\u003cp\u003eMediation model of the effect of NAA/Cr rations in cerebellar on the ICARS scores, with age as a covariate. a - f indicate unstandardized regression coefficients for each path; statistically significant pathways are shown in bold and marked with solid lines. Acronyms: NAA/Cr - N-acetyl aspartate/creatine; NfL - neurofilament light chain; ICARS - International Cooperative Ataxia Rating Scale.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/bc6006055853bb22e4bea70b.png"},{"id":44716177,"identity":"3b6746a8-336e-4bf6-ad94-4ff344eead88","added_by":"auto","created_at":"2023-10-16 18:23:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":813296,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/4e4a153b-d101-4da3-9284-7855b1419f31.pdf"},{"id":27782556,"identity":"e385cc52-54bd-4fd0-a74a-b30b140a3511","added_by":"auto","created_at":"2022-10-14 14:42:30","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":10491,"visible":true,"origin":"","legend":"","description":"","filename":"Figurelegends.docx","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/071c2bbc08e8d3399c97eaa1.docx"},{"id":27782562,"identity":"4304e214-4b49-4ac7-b441-12d9bb50468b","added_by":"auto","created_at":"2022-10-14 14:42:30","extension":"tiff","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":8691310,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementalfigure1.tiff","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/b83bf838909e8d7b46c6e849.tiff"},{"id":27782560,"identity":"5359ea98-09fe-4777-8e9c-04c1dd465fbd","added_by":"auto","created_at":"2022-10-14 14:42:30","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":16512,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaltable1.docx","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/32fc798bf357ea657a584f7f.docx"},{"id":27782890,"identity":"0ea5555d-8aef-4b8f-9f9d-75be08a42b09","added_by":"auto","created_at":"2022-10-14 14:47:30","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":15687,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaltable2.docx","url":"https://assets-eu.researchsquare.com/files/rs-2132253/v1/a7ae81f64bcf940f2cf38650.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Association between with Serum neurofilament light and neurochemistry deficits in patients with spinocerebellar ataxia type 3","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSpinocerebellar ataxia type 3 (SCA3) is the most frequent autosomal dominant ataxia worldwide, and it is caused by an abnormal CAG expansion at exon 10 of the \u003cem\u003eATXN3\u003c/em\u003e gene [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The number of CAG trinucleotide repeats in \u003cem\u003eATXN3\u003c/em\u003e ranges from 12 to 44, whereas at least one expanded allele ranging between 52 and 87 CAG repeats is defined as an expanded repeat [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. SCA3 is a disease characterized clear clinical heterogeneity. It mainly involves progressive cerebellar ataxia, pyramidal signs, and extrapyramidal syndrome. Non-characteristic manifestations, such as spastic paraplegia phenotypes, cognitive, psychiatric disturbances, and sleep disorders, have also been observed [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ethe expansion of CAG repeats in the ATXN3 gene can express the abnormal folding protein, which leads to selective neuronal cell death along with neurochemical alterations that can be visualized using magnetic resonance spectroscopy (MRS), including decreases in acetylcholine and N-acetyl aspartate (NAA) [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. NAA has long been used as a marker of neuronal integrity and viability, and it is one of the most important brain metabolites determined by proton MRS [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. MRS can reveal early metabolic/cellular changes in various spinocerebellar ataxia types (SCAs), likely to occur before cerebellar signs are obvious, and even before brain atrophy. This indicates that the measurement of neurochemical changes in brain tissue by MRS may be superior to clinical observation in specific circumstances [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough promising drugs for \u003cem\u003eATXN3\u003c/em\u003e expansion have emerged in preclinical studies, biomarkers for evaluating their efficacy have not been adequately assessed in humans. Disease-modifying therapies advancing toward clinical trials include antisense oligonucleotides (ASOs) that target \u003cem\u003eATXN3\u003c/em\u003e RNA transcripts, reducing the expression of abnormal proteins in SCA3 animal models and patient-derived cell models [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, in parallel with the rapid development of these potential therapeutics, biomarkers that measure target engagement, disease onset, and disease progression must be established for clinical trials to be successful. Previous studies suggest that serum neurofilament light chain (sNfL) is a promising marker of target engagement in SCA3, which is detectable in the presymptomatic and symptomatic SCA3 cohort [\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003esNfL levels and cerebellar metabolites of NAA/Cr ratios have been found to be biomarkers of neuro-axonal damage in SCA3/MJD patients, but the relationship between them is still unclear. Therefore, this study was performed to assess whether there is a significant association between cerebellar NAA/Cr values and indicators of neurodegeneration, as reflected by sNfL levels.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSubjects\u003c/h2\u003e \u003cp\u003e This study was approved by the Ethics Committee of the Affiliated Hospital of Hangzhou Normal University. Informed consent was obtained from all subjects before participation in the study. In our study, 20 unrelated patients with genetically confirmed SCA3 and 14 healthy controls were recruited consecutively between March 2020 and May 2022 from the Department of Neurology in the Affiliated Hospital of Hangzhou Normal University. These normal participants were matched for age and sex at the group level. Serum samples were obtained from 20 patients with ataxia features caused by the \u003cem\u003eATXN3\u003c/em\u003e repeat expansion and 14 normal individuals. The Scale for the Assessment and Rating of Ataxia (SARA) and the International Cooperative Ataxia Rating Scale (ICARS) were used to measure the severity of ataxia symptoms at the time of serum collection.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eProton Magnetic Resonance Spectroscopy (H-mrs)\u003c/h3\u003e\n\u003cp\u003eAll participants underwent identical MR procedures using a Siemens 1.5T magnetic resonance imaging (MRI) scanner. \u003csup\u003e1\u003c/sup\u003eH-MRS measurements were then performed to determine the value of N-acetyl aspartate (NAA)/creatine (Cr), and choline complex (Cho)/Cr in local cerebellar metabolites [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The multiple-voxel \u003csup\u003e1\u003c/sup\u003eH-MRS sequence was acquired with the following parameters: repetition time (TR)\u0026thinsp;=\u0026thinsp;4,280 ms, echo time (TE)\u0026thinsp;=\u0026thinsp;135 ms, and voxel size\u0026thinsp;=\u0026thinsp;6.3 mm \u0026times; 6.3 mm \u0026times; 15 mm. We selected the target as the cerebellum, which includes the bilateral cerebellar hemispheres, the dentate nucleus, and the cerebellar vermis, in sequence by voxel. The local cerebellar metabolites consisted of the values of NAA/Cr and Cho/Cr, as detected via a proton MR wave.\u003c/p\u003e\n\u003ch3\u003eSnfl Levels (Dup: Abstract ?)\u003c/h3\u003e\n\u003cp\u003eSerum samples were taken from all participants and collected according to standardized local procedures. Then, the serum samples were aliquoted and immediately stored at -80\u0026deg;C. sNfL concentrations were detected using a single-molecule (Simoa) array method and then quantified on the Simoa HD-1 Analyzer platform (GBIO, Hangzhou, China), using a Simoa NF-light Advantage Kit (Quanterix, Massachusetts, USA) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. All sNfL concentrations were within the linear ranges of this assay.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed using SPSS 25.0 for Mac (Armonk, NY), and graphs were drafted with GraphPad Prism 7 (La Jolla, CA). Test statistics were considered significant at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (two-tailed). The data for numerical variables were described as the mean (standard deviation) if normally distributed or median (interquartile range) if non-normally distributed. We tested the normality of variables using the Shapiro\u0026ndash;Wilk test, and we tested the homogeneity of variances using the Levene test. For variables in line with the assumptions of normality and homogeneity of variances, the groups were compared with a \u003cem\u003et\u003c/em\u003e-test with Bonferroni correction for further multiple comparisons, if applicable. For variables not in line with the assumptions of normality, the groups were compared using a nonparametric Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e test, with Bonferroni correction for further multiple comparisons, if applicable.\u003c/p\u003e \u003cp\u003eCorrelation analyses were performed to investigate the relationships between the sNfL level and cerebellar metabolite changes, including in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere. Specifically, cerebellar metabolite changes were fitted with the individual sNfL level as a covariate while adjusting for the effects of age and intracranial volume on the relationship between the sNfL and GM volume. Then, correction for multiple comparisons at the cluster level at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was used to perform the correlation analyses between the sNfL and the cerebellar metabolite changes.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eDemographic and Clinical Data\u003c/h2\u003e \u003cp\u003eIn total, this study included 20 SCA3 patients and 14 healthy controls. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the sociodemographic, clinical, and biomarker characteristics of all participants. No significant differences in age or gender were observed between the SCA3 patients and the controls (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). The median age for serum collection in patients with SCA3 was 39.2 years; the median age at disease onset was 32.5 years, but this age varied widely (23\u0026ndash;64 years). The median CAG repeat length of the SCA3 patients was 74.6. The median SARA and ICARS scores for all SCA3 carriers were 12.54 and 34.35, respectively. The sNfL concentrations were 4.76 times higher in the 20 ATXN3 mutation carriers than they were in age-matched healthy controls.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic, clinical, and biochemical characteristics of controls and SCA3 patients.\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHealth Control\u003c/p\u003e \u003cp\u003e(mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSCA3\u003c/p\u003e \u003cp\u003e(mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\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\u003eNumber\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender, Male: Female\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10: 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14: 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.928\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at serum collection (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34.64\u0026thinsp;\u0026plusmn;\u0026thinsp;7.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39.20\u0026thinsp;\u0026plusmn;\u0026thinsp;11.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.198\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at onset (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32.5\u0026thinsp;\u0026plusmn;\u0026thinsp;10.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuration of disease (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCAG repeat length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSARA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.54\u0026thinsp;\u0026plusmn;\u0026thinsp;4.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICARS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34.35\u0026thinsp;\u0026plusmn;\u0026thinsp;12.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eposture and gait\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.15\u0026thinsp;\u0026plusmn;\u0026thinsp;6.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003elimb kinetic function\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.90\u0026thinsp;\u0026plusmn;\u0026thinsp;6.263\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003espeech disorders\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eoculomotor disorders\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSerum NfL, pg/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.43\u0026thinsp;\u0026plusmn;\u0026thinsp;2.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.33\u0026thinsp;\u0026plusmn;\u0026thinsp;9.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMRS available, n\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eSARA, the Scale for the Assessment and Rating of Ataxia; ICARS, the International Cooperative Ataxia Rating Scale; NfL, neurofilament light chain; MRS, magnetic resonance spectroscopy; n/a, not available. a, Chi-squared test; b, dependent samples t-test.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eBrain Metabolite Levels\u003c/h3\u003e\n\u003cp\u003eWith available MRS results, we found that the values of the NAA/Cr and NAA/Cho ratios were significantly reduced in the dentate nucleus and cerebellar vermis in the \u003cem\u003eATXN3\u003c/em\u003e expansion carriers compared with that in the normal controls (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, dentate nucleus; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, cerebellar vermis), whereas only the NAA/Cr ratio was significantly decreased in the cerebellar cortex (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01, cer ebellar cortex); the values of the Cho/Cr ratio in the three regions of interest (ROIs) did not differ between SCA3 patients and normal controls (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e; \u003cb\u003eSupplemental Table\u0026nbsp;1\u003c/b\u003e). In addition, no significant differences in the NAA/Cr, Cho/Cr, or NAA/Cho ratio were observed in the three ROIs of the left and right cerebellum (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eIn all SCA3 carriers, the total SARA and ICARS scores negatively correlated with the NAA/Cr ratio (dentate nucleus: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;689, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; cerebellar vermis: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.553, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.011; cerebellar hemisphere: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.493, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.027), but they did not correlate with the NAA/Cho ratio in the three ROIs. Likewise, similarly negative correlation results were identified in the three ROIs between the total ICARS scores with the NAA/Cr ratio (dentate nucleus: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;691, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; cerebellar vermis: r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.537, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.015; cerebellar hemisphere: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.486, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.03), and the ICARS scores did not correlate with the NAA/Cho ratio in the three ROIs. In addition, the Cho/Cr ratios in the dentate nucleus and cerebellar vermis did not correlate with the total SARA and ICARS scores; however, they did negatively correlate with these scores in the cerebellar hemisphere (SARA: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.576, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.008, ICARS: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.506, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.023). To confirm the robustness of the primary findings, After the analysis of Bonferroni\u0026rsquo;s corrected \u003cem\u003ep\u003c/em\u003e-value (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.016) was performed, the NAA/Cr values in the dentate nucleus and cerebellar vermis were still negatively correlated with the SARA and ICARS scores, whereas the NAA/Cr values in the cerebellar hemisphere did not correlate with the SARA or ICARS scores. The Cho/Cr ratio in the cerebellar hemisphere was also still negatively correlated with the SARA and ICARS scores after the Bonferroni test. No significant associations were found between the values of the NAA/Cr and NAA/Cho ratios and age at disease onset, disease duration, or CAG repeats in patients with SCA3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003ch3\u003eSnfl Levels\u003c/h3\u003e\n\u003cp\u003eAt the time of serum collection, the \u003cem\u003eATXN3\u003c/em\u003e expansion carriers had higher NfL levels (median: 35.33 pg/mL) compared with the healthy controls (median: 7.43 pg/mL, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001; Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This observation was still statistically significant upon correction for age (post hoc Bonferroni-corrected \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.04). In participants with SCA3, the NfL levels were not associated with age at serum collection, age at onset, disease duration, or CAG repeats, but they were negatively correlated with the SARA and ICARS scores (SARA: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.472, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.036; ICARS: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.465, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.039). sNfL did not correlate with posture and gait, limb kinetic function and or oculomotor disorders in any subgroup of ICARS scores, but it was significantly correlated with speech disorders (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.620, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.004). We also used age as a covariate because of its general association with sNfL levels. Statistical values demonstrated the significant correction between the NfL concentration and the SARA and ICARS scores in the SCA3 patients but not the subgroups of ICARS scores.\u003c/p\u003e\n\u003ch3\u003eAssociations Of Nfl Levels With Brain Metabolite Levels\u003c/h3\u003e\n\u003cp\u003eIn all SCA3 patients, higher sNfL levels were associated with lower cerebellar hemisphere, cerebellar vermis, and dentate nucleus NAA/Cr and NAA/Cho levels; however, the latter two ROIs did not survive multiple comparisons correction. Higher NfL levels were correlated with lower NAA/Cr ratios in the dentate nucleus (DN), cerebellar vermis (CV), and cerebellar hemisphere (CH) (DN: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.502, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.024; CV: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.486, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.013; CH: \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;572, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.008). Higher NfL values did not correlate with the levels of NAA/Cho in the dentate nucleus (DN: \u003cem\u003er\u003c/em\u003e = -0.358, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.122), but negatively correlated with the NAA/Cho in the cerebellar vermis and cerebellar hemisphere (CV: \u003cem\u003er\u003c/em\u003e = -0.582, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.007; CH: \u003cem\u003er\u003c/em\u003e = -0.656, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.002; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). No significant correlations between the Cho/Cr ratio in the three ROIs and NfL emerged. Age was used as a covariate to remove variance, which correlated in the sNfL levels and brain metabolite levels. Upon correction for age (post hoc \u003cem\u003eBonferroni\u003c/em\u003e corrected \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.016), higher NfL levels were significantly associated with lower NAA/Cho levels in the cerebellar hemisphere and cerebellar vermis. Moreover, NfL levels correlated with lower NAA/Cr levels in the cerebellar hemisphere, whereas they showed no significant correlation in the cerebellar vermis region; and no significant association was found between NfL levels and the NAA/Cr and NAA/Cho ratios in SCA3 patient at Bonferroni-corrected \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.016 and the normal controls (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\u003eAssociations between neurochemistry of the 1H-MRS scan and NfL in the SCA3 patients.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eRegions of\u003c/p\u003e \u003cp\u003einterest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMetabolic\u003c/p\u003e \u003cp\u003eratios\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eNfL\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eControls\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eSCA3 patients\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003eDentate nucleus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.091\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.502\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.648\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.024\u003c/b\u003e\u003csup\u003e\u003cb\u003ea\u003c/b\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eCho/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.087\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.193\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.662\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.414\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cho\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.042\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.358\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.836\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.122\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003eCerebellar vermis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.486\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.411\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.03\u003c/b\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eCho/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.058\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.013\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.776\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.956\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cho\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.175\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.582\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.378\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003eCerebellar cortex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.048\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.572\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.813\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eCho/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.090\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.663\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.901\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAA/Cho\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003er\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-0.091\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.656\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.652\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.002\u003c/b\u003e\u003csup\u003e\u003cb\u003eb\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eAssociations between Serum NfL concentrations and neurochemistry of the 1HMRS images in controls and SCA3 patients, by means of linear regression. P-values below 0.05 are bolded. NfL, neurofilament light chain; NAA, N-acetyl-aspartate; Cho, choline-containing compounds; Cr, creatine and phosphocreatine. a, spearman tests; b, Pearson test. *Significant after correction for multiple testing (Bonferroni corrected P-value: P\u0026thinsp;\u0026lt;\u0026thinsp;0.016, three tests).\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn the current study, sNfL and cerebellar metabolite levels were determined in a cohort of 20 SCA3 patients to examine associations between the two measures. Compared with controls, we found high NfL levels and lower cerebellar metabolite levels, including NAA/Cr and NAA/Cho ratios, in 20 ATXN3 expansion carriers. Both measures\u0026mdash;cerebellar metabolite and NfL levels\u0026mdash;correlated with greater disease severity in our patients with SCA3. In addition, elevated NfL levels were associated with lower cerebellar metabolite levels; especially, low levels in NAA/Cr values are known to indicate cerebellar degeneration in ATXN3 repeat expansion carriers. As such, sNfL levels and cerebellar metabolites capture abnormalities in SCA3 patients, and thus, they may serve as complementary biomarkers for disease detection and future treatment monitoring.\u003c/p\u003e \u003cp\u003eIn SCA3 disease, polyQ-expanded ATXN3 leads to protein neurotoxicity and causes selective neuronal cell death along with metabolic/cellular changes detected by MRS, including decreases in acetylcholine and NAA [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Emerging evidence has shown early neurochemical alterations in patients with SCA3 in the preclinical stage, even before brain atrophy [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In this regard, the measure of the NAA/Cr ratios has been found to be a good neuroimaging biomarker and can be used to monitor the clinical progression of SCA3 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In the current study, our findings demonstrated a decrease of the NAA/Cr and NAA/Cho ratios in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere, suggesting that the degree of neuronal dysfunction in SCA3 would be consistent with previous findings [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Associations between ataxia severity and metabolic/cellular changes have been described as reflected by NAA/Cr ratios. Our findings also showed that ICARS scores were negatively correlated with NAA/Cr ratios in the three ROIs of the dentate nucleus, cerebellar vermis, and cerebellar hemisphere in 20 SCA3 patients, which is in line with previous results [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Furthermore, we found that SARA scores had an inverse relationship with NAA/Cr ratios in these ROIs. These results further confirmed that the metabolic alterations of the cerebellum were correlated to the predominant clinical features in SCA3 patients and suggested that NAA is a good marker for SCA3 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNeurofilament light protein can be released in significant quantities following neuro-axonal damage or neurodegeneration. The elevation of sNfL is considered a biomarker of clinical disease severity in SCA3 [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Higher NfL levels are not only correlated with ataxia symptoms and non-ataxia signs in ataxic SCA3 patients, but they show similar correlations in preclinical SCA3 individuals [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Our findings were consistent with a previously published study on SCA3, which also found that NfL was elevated in patients with SCA3 and that NfL levels correlated with ataxia symptoms [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This correlation between elevated NfL levels and clinical severity could persist after accounting for the potential confounder of age.\u003c/p\u003e \u003cp\u003eIn our patients with SCA3, both higher sNfL levels and decreased metabolites in the cerebellum significantly correlated with clinical severity, as reflected by the ICARS scores. Therefore, we hypothesized that the elevation of NfL values may be correlated with a lower cerebellar NAA/Cr ratio. Our study also explored the association between NfL and MRI features in a subgroup of ataxic SCA3 patients. First, our ROI analysis showed that certain cerebellar regions with a lower NAA/Cr ratio tended to be significantly associated with higher NfL levels, which included regions in the dentate nucleus, cerebellar vermis, and cerebellar hemisphere. Furthermore, higher NfL levels also showed an association with a reduced NAA/Cho ratio in the cerebellar vermis and cerebellar hemisphere, but a similar association was not found in the dentate nucleus in our analyses. Third, unexpectedly, there was no significant relationship between increased NfL and the Cho/Cr ratio in the cerebellum. One potential explanation for this result is that the Cho/Cr ratio was not observed to decrease in our patients. This finding suggests that the elevation of NfL was mainly associated with neuronal dysfunction rather than cell membrane or neurotransmitter metabolism impairment in our SCA3 patients, likely indicating the subtle impairment of neurofilaments in the cerebellum. Regarding these findings, further studies are needed to explore the association between the NAA/Cr ratio and sNfL in SCA3.\u003c/p\u003e \u003cp\u003eBoth higher NfL levels and decreased cerebellar metabolites have been suggested to reflect neuronal dysfunction not only in SCA3 but also in other degenerative diseases [\u003cspan additionalcitationids=\"CR25 CR26\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In our samples, we found both measures\u0026mdash;NAA/Cr ratios and sNfL levels\u0026mdash;to be significant predictors of clinical severity, reflected as ICARS scores. However, it is difficult to estimate the relevance of sNfL levels because changes in these levels may possibly result from shifts of NAA/Cr, NAA/Cho, or both metabolites simultaneously. In this study, a mediation model based on a multiple regression approach helped us clarify how prominent the contribution of each component was. As the limited statistical power did not allow us to test a model with two mediators (NAA/Cr and NAA/Cho), we used two separate models with either the NAA/Cr ratio or NAA/Cho ratio as the mediator; the results indicated that in our patients with SCA3, the prediction of clinical severity by NfL was more likely to be driven by changes in the NAA/Cr ratio (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) but not changes in the NAA/Cho ratio (\u003cb\u003eSupplemental Table\u0026nbsp;2; Supplemental Fig.\u0026nbsp;1\u003c/b\u003e). sNfL levels and cerebellar metabolites of NAA/Cr ratio are both the biomarkers of neuro-axonal damage in patients with SCA3. The serum NfL levels often reflect the neuron damage in the whole brain, while NAA/Cr ratio reflects the damage in part of the cerebellum in SCA3, which may explain why NAA/Cr ratio acts as a mediator. Considering the limited sample size and possible VOI localizations detected by MRS scanning, methods based on multiple regression analysis appear to improve our understanding of the cerebellar metabolic process in the SCA3 cohorts above conventional analysis of variance; they also provide more evidence of the putative mechanism by allowing testing of specific mechanistic models.\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\u003eSummary of Model Coefficients: Effect of serum NfL on clinical severity Mediated by NAA/Cr ratio Moderated\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModel 1a\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003eNAA/Cr ratios\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003eF(2)\u0026thinsp;=\u0026thinsp;4.9733, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0199*, \u003cem\u003eR\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.3691\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ecoef\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eSE\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003et\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003ep\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNfL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ea\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.0155\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.0053\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-2.9471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.009\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ef\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.0045\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.0042\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-1.0620\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.3031\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConstant\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.6538\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.2501\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.6126\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eModel 1b\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003e\u003cb\u003eICARS scores\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003eF(3)\u0026thinsp;=\u0026thinsp;8.8199, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0011**, \u003cem\u003eR\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.632\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ecoef\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eSE\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003et\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003ep\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNfL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ec'\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.2232\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.2578\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.8656\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.3995\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNAA/Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eb\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-25.7773\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.6889\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-2.6605\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.0171\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eg\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.422\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1738\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.4273\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.0274\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConstant\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.9433\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18.8833\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.7975\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.0911\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDirect effect\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003e\u003cb\u003eNfL-ICARS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ecoef\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eSE\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003et\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003ep\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.2232\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.2578\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.8656\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.3995\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIndirect effect\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003e\u003cb\u003eNfL-NAA/Cr-ICARS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003ecoef\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eBootSE\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eBootLLCI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003eBootULCI\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.2538\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.0291\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.9927\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eSeveral potential limitations restrict the interpretability of our findings. First, the limited sample size was not sufficient to draw an affirmative conclusion in our cohort; thus, the findings need to be further validated in a larger cohort. Second, information on asymptomatic SCA3 patients was not available, which makes it difficult to analyze the correlation between cerebellar metabolites and sNfL levels. Third, not only should the neurochemical values of NAA, Cho, and Cr be included, but Gln, Glu, and Tau should also be determined; doing this could help to further explore the correction with sNfL in future research. Finally, while the mediated moderation analysis in our present study provides evidence for an associated effect, we need to acknowledge that effects were only significant for ICARS (but not SARA) scores and need to be replicated in future research.\u003c/p\u003e \u003cp\u003eIn summary, we used a multimodal approach combining the serum biomarker with cerebellar metabolites to investigate the association between NfL and indicators of neurodegeneration in 20 SCA3 patients. To the best of our knowledge, this is the first study to examine correlated NfL levels with the cerebellar metabolites reflected by the NAA/Cr ratio in \u003cem\u003eATXN3\u003c/em\u003e mutation carriers. Our results confirmed that sNfL levels are increased in SCA3 and that they are correlated with clinical disease severity, reflected as ICARS and SARA scores, as well as brain metabolic changes. We demonstrated that the NfL level and cerebellar metabolites were promising complementary biomarkers that capture the effects of the expansion \u003cem\u003eATXN3\u003c/em\u003e mutation. In addition, our multiple regression models revealed that the decrease in the NAA/Cr ratio mediated this prediction effect. Additional longitudinal studies are strongly warranted to build on these results in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe local medical ethics committee of the affiliated hospital of Hangzhou normal university approved the study and written informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors report no potential conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData available upon request to the authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eY.C. Chen designed the work. Y.C. Chen, Y. Jin, Z.Y. Hu, M.Q. Qiu, D. Li, Q.S. Cai, C.J. Tao, D.N. Lou, L. Qi, S.D. Chen, H. Yu, Z.M. Gao initiated the project. Y.C. Chen, Y. Jin, Z.Y. Hu, M.Q. Qiu, D. Li, Q.S. Cai, C.J. Tao, D.N. Lou, L. Qi, S.D. Chen, H. Yu, Z.M. Gao collected and analyzed the data. Y.C. Chen wrote the manuscript. H. Yu, Z.M. Gao commented and revised on the manuscript. Y.C. Chen supervised all aspects of the project. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the grants, 2021KY898 (YCC) and 2021YN2021099 (YCC), from the Medical and Health Science and Technology Project of Zhejiang Province, and Youth cultivation foundation of Affiliated Hospital of Hangzhou Normal University.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eORCID\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYuchao Chen https://orcid.org/0000-0002-0255-060X\u003c/p\u003e\n\u003cp\u003eYi Jin https://orcid.org/0000-0001-9989-3934\u003c/p\u003e\n\u003cp\u003eZhouyao Hu https://orcid.org/0000-0003-2579-4508\u003c/p\u003e\n\u003cp\u003eMengqiu Qiu https://orcid.org/0000-0002-5299-9747\u003c/p\u003e\n\u003cp\u003eDan Li https://orcid.org/0000-0003-1987-8852\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKawaguchi Y, Okamoto T, Taniwaki M, Aizawa M, Inoue M, et al. 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Alzheimers Dement. 2020; 16:681-95. doi 10.1016/j.jalz.2019.09.004.\u003c/li\u003e\n\u003cli\u003eAamodt WW, Waligorska T, Shen J, Tropea TF, Siderowf A, et al. Neurofilament Light Chain as a Biomarker for Cognitive Decline in Parkinson Disease. Movement disorders : official journal of the Movement Disorder Society. 2021; 36:2945-50. doi 10.1002/mds.28779.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"the-cerebellum","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cere","sideBox":"Learn more about [The Cerebellum](http://link.springer.com/journal/12311)","snPcode":"12311","submissionUrl":"https://submission.nature.com/new-submission/12311/3","title":"The Cerebellum","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Serum neurofilament light, sNfL, NAA/Cr, SCA3","lastPublishedDoi":"10.21203/rs.3.rs-2132253/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2132253/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eExtensive evidence supports the claim that serum neurofilament light chain (sNfL) can be used as a biomarker for monitoring disease severity in patients with spinocerebellar ataxia type 3 (SCA3). However, little is known about the associations between sNfL levels and neurochemical alterations in SCA3 patients. Serum samples were collected from \u003cem\u003eATXN3\u003c/em\u003e mutation carriers (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;20) and normal controls (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;14). sNfL levels, measured by a single-molecule array, were compared between SCA3 patients and controls. We explored the relationship between sNfL levels and metabolic changes via magnetic resonance spectroscopy (MRS) scans. sNfL levels in SCA3 patients were higher than those in healthy controls, and these levels were correlated with disease severity. Associations emerged between the elevation of sNfL levels and lower brain metabolite changes, reflected as N-acetyl aspartate/creatine (NAA/Cr). These associations remained significant after multiple comparison corrections. Our results confirmed that serum sNfL levels are increased in SCA3 and are correlated with cerebellar hemisphere metabolic changes. Brain metabolic changes and sNfL levels show promise as potential complementary biomarkers for clinical trials for patients with SCA3.\u003c/p\u003e","manuscriptTitle":"Association between with Serum neurofilament light and neurochemistry deficits in patients with spinocerebellar ataxia type 3","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-10-14 14:42:27","doi":"10.21203/rs.3.rs-2132253/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-10-24T14:43:03+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-10-17T17:16:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"a2898513-12ee-40ed-bbf2-0acbf1a1c8b2","date":"2022-10-17T11:56:53+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-10-17T09:05:43+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-10-12T16:50:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-10-11T07:08:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"The Cerebellum","date":"2022-10-04T14:34:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-cerebellum","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cere","sideBox":"Learn more about [The Cerebellum](http://link.springer.com/journal/12311)","snPcode":"12311","submissionUrl":"https://submission.nature.com/new-submission/12311/3","title":"The Cerebellum","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f398619b-a2cd-4671-b21e-d81f4253a295","owner":[],"postedDate":"October 14th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T18:19:40+00:00","versionOfRecord":{"articleIdentity":"rs-2132253","link":"https://doi.org/10.1007/s12311-022-01507-z","journal":{"identity":"the-cerebellum","isVorOnly":false,"title":"The Cerebellum"},"publishedOn":"2023-01-04 18:13:46","publishedOnDateReadable":"January 4th, 2023"},"versionCreatedAt":"2022-10-14 14:42:27","video":"","vorDoi":"10.1007/s12311-022-01507-z","vorDoiUrl":"https://doi.org/10.1007/s12311-022-01507-z","workflowStages":[]},"version":"v1","identity":"rs-2132253","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2132253","identity":"rs-2132253","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}