Protamine protects against Vancomycin Induced Kidney Injury

Protamine protects against Vancomycin Induced Kidney Injury | bioRxiv /* */ /* */ <!-- <!-- /*! * yepnope1.5.4 * (c) WTFPL, GPLv2 */ (function(a,b,c){function d(a){return"[object Function]"==o.call(a)}function e(a){return"string"==typeof a}function f(){}function g(a){return!a||"loaded"==a||"complete"==a||"uninitialized"==a}function h(){var a=p.shift();q=1,a?a.t?m(function(){("c"==a.t?B.injectCss:B.injectJs)(a.s,0,a.a,a.x,a.e,1)},0):(a(),h()):q=0}function i(a,c,d,e,f,i,j){function k(b){if(!o&&g(l.readyState)&&(u.r=o=1,!q&&h(),l.onload=l.onreadystatechange=null,b)){"img"!=a&&m(function(){t.removeChild(l)},50);for(var d in y[c])y[c].hasOwnProperty(d)&&y[c][d].onload()}}var j=j||B.errorTimeout,l=b.createElement(a),o=0,r=0,u={t:d,s:c,e:f,a:i,x:j};1===y[c]&&(r=1,y[c]=[]),"object"==a?l.data=c:(l.src=c,l.type=a),l.width=l.height="0",l.onerror=l.onload=l.onreadystatechange=function(){k.call(this,r)},p.splice(e,0,u),"img"!=a&&(r||2===y[c]?(t.insertBefore(l,s?null:n),m(k,j)):y[c].push(l))}function j(a,b,c,d,f){return q=0,b=b||"j",e(a)?i("c"==b?v:u,a,b,this.i++,c,d,f):(p.splice(this.i++,0,a),1==p.length&&h()),this}function k(){var a=B;return a.loader={load:j,i:0},a}var l=b.documentElement,m=a.setTimeout,n=b.getElementsByTagName("script")[0],o={}.toString,p=[],q=0,r="MozAppearance"in l.style,s=r&&!!b.createRange().compareNode,t=s?l:n.parentNode,l=a.opera&&"[object Opera]"==o.call(a.opera),l=!!b.attachEvent&&!l,u=r?"object":l?"script":"img",v=l?"script":u,w=Array.isArray||function(a){return"[object Array]"==o.call(a)},x=[],y={},z={timeout:function(a,b){return b.length&&(a.timeout=b[0]),a}},A,B;B=function(a){function b(a){var a=a.split("!"),b=x.length,c=a.pop(),d=a.length,c={url:c,origUrl:c,prefixes:a},e,f,g;for(f=0;f<d;f++)g=a[f].split("="),(e=z[g.shift()])&&(c=e(c,g));for(f=0;f<b;f++)c=x[f](c);return c}function g(a,e,f,g,h){var i=b(a),j=i.autoCallback;i.url.split(".").pop().split("?").shift(),i.bypass||(e&&(e=d(e)?e:e[a]||e[g]||e[a.split("/").pop().split("?")[0]]),i.instead?i.instead(a,e,f,g,h):(y[i.url]?i.noexec=!0:y[i.url]=1,f.load(i.url,i.forceCSS||!i.forceJS&&"css"==i.url.split(".").pop().split("?").shift()?"c":c,i.noexec,i.attrs,i.timeout),(d(e)||d(j))&&f.load(function(){k(),e&&e(i.origUrl,h,g),j&&j(i.origUrl,h,g),y[i.url]=2})))}function h(a,b){function c(a,c){if(a){if(e(a))c||(j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}),g(a,j,b,0,h);else if(Object(a)===a)for(n in m=function(){var b=0,c;for(c in a)a.hasOwnProperty(c)&&b++;return b}(),a)a.hasOwnProperty(n)&&(!c&&!--m&&(d(j)?j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}:j[n]=function(a){return function(){var b=[].slice.call(arguments);a&&a.apply(this,b),l()}}(k[n])),g(a[n],j,b,n,h))}else!c&&l()}var h=!!a.test,i=a.load||a.both,j=a.callback||f,k=j,l=a.complete||f,m,n;c(h?a.yep:a.nope,!!i),i&&c(i)}var i,j,l=this.yepnope.loader;if(e(a))g(a,0,l,0);else if(w(a))for(i=0;i (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];var j=d.createElement(s);var dl=l!='dataLayer'?'&l='+l:'';j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;j.type='text/javascript';j.async=true;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-M677548'); Skip to main content Home About Submit ALERTS / RSS Search for this keyword Advanced Search New Results Protamine protects against Vancomycin Induced Kidney Injury View ORCID Profile Justin Shiau , View ORCID Profile Patti Engel , View ORCID Profile Mark Olsen , View ORCID Profile Gwendolyn Pais , View ORCID Profile Jack Chang , View ORCID Profile Marc H. Scheetz doi: https://doi.org/10.1101/2024.08.12.607677 Justin Shiau 1 Midwestern University, College of Pharmacy, Department of Pharmacy Practice , Downers Grove, IL, USA ; 2 Northwestern Memorial Hospital, Department of Pharmacy , Chicago, IL, USA ; 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Justin Shiau Patti Engel 1 Midwestern University, College of Pharmacy, Department of Pharmacy Practice , Downers Grove, IL, USA ; 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Patti Engel Mark Olsen 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; 4 Midwestern University, College of Pharmacy, Department of Pharmaceutical Sciences , Glendale, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Mark Olsen Gwendolyn Pais 1 Midwestern University, College of Pharmacy, Department of Pharmacy Practice , Downers Grove, IL, USA ; 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Gwendolyn Pais Jack Chang 1 Midwestern University, College of Pharmacy, Department of Pharmacy Practice , Downers Grove, IL, USA ; 2 Northwestern Memorial Hospital, Department of Pharmacy , Chicago, IL, USA ; 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Jack Chang Marc H. Scheetz 1 Midwestern University, College of Pharmacy, Department of Pharmacy Practice , Downers Grove, IL, USA ; 2 Northwestern Memorial Hospital, Department of Pharmacy , Chicago, IL, USA ; 3 Midwestern University, College of Pharmacy, Pharmacometrics Center of Excellence , Downers Grove, IL, USA ; 5 Midwestern University, College of Graduate Studies, Department of Pharmacology , Downers Grove, IL, USA ; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Marc H. Scheetz For correspondence: mschee{at}midwestern.edu Abstract Full Text Info/History Metrics Preview PDF ABSTRACT Introduction Vancomycin causes kidney injury by accumulating in the proximal tubule, likely mediated by megalin uptake. Protamine is a putative megalin inhibitor that shares binding sites with heparin and is approved for heparin overdose in patients. Methods We employed a well characterized Sprague Dawley rat model to assess kidney injury and function in animals that received vancomycin, protamine alone, or vancomycin plus protamine over 5 days. Urinary KIM-1 was used as the primary measure for kidney injury while iohexol clearance was calculated to assess kidney function. Animals had samples drawn pre-treatment to serve as their own controls. Additionally, since protamine is not a known nephrotoxin, the protamine group also served as a control. Cellular inhibition studies were performed to assess the ability of protamine to inhibit OAT1, OAT3, and OCT2. Results Rats that received vancomycin had significantly increased urinary KIM-1 on day 2 (24.9 ng/24h, 95% CI 1.87 to 48.0) compared to the protamine alone group. By day 4, animals that received protamine with vancomycin had urinary KIM-1 amounts that were elevated compared to protamine alone (KIM-1 29.0 ng/24h, 95% CI 5.0 to 53.0). No statistically significant differences were identified for iohexol clearance changes between drug groups or when comparing clearance change from baseline (P>0.05). No substantial inhibition of OAT1, OAT3, or OCT2 was observed with protamine. IC 50 values for protamine were 1e-4 M for OAT1 and OAT3 and 4.3e-5 M for OCT2. Conclusion Protamine, when added to vancomycin therapy, delays vancomycin induced kidney injury as defined by urinary KIM-1 in the rat model by one to three days. Protamine putatively acts through blockade of megalin and does not appear to have significant inhibition on OAT1, OAT3, or OCT2. Since protamine is an approved FDA medication, it has clinical potential as a therapeutic to reduce vancomycin related kidney injury; however, greater utility may be found by pursuing compounds with fewer adverse event liabilities. INTRODUCTION Vancomycin is one of the most widely used antibiotics within United States in-patient healthcare systems, accounting for 11.9% of all antibiotic use (1,258 out of 10,612) in a 2015 hospital survey ( 1 ). As a tricyclic glycopeptide, it is primarily indicated for severe Gram-positive bacterial infections including methicillin-resistant Staphylococcus aureus ( 2 ). For about 70 years now, vancomycin has remained a gold-standard antibiotic widely used and studied across people of all ages. Despite its efficacy in the treatment of severe infections, one common limitation of its use is the association with acute kidney injury (AKI) ( 3 ). A systematic review and meta-analysis found that vancomycin is associated with a higher risk of AKI up to 2.5 times greater compared to other antibiotics ( 4 ). Vancomycin kidney injury is attributed to two primary mechanisms, intracellular accumulation and complex formation with uromodulin and blockade of the proximal tubule ( 5 , 6 ). While the individual contributions of each mechanism to the extent of kidney injury is not yet clear, intracellular accumulation is a hallmark ( 3 , 6 – 8 ). Cellular accumulation occurs through multiple pathways both basolatereally and apically ( 6 ). Basolaterally, vancomycin is actively transported from blood circulation into kidney proximal tubule cells through the organic cation transporter (OCT)-2, located on the basolateral membrane of the tubular cell. Next, it is secreted into the tubular lumen from the apical membrane of the proximal tubule by an eflux transporter, P-glycoprotein ( 9 , 10 ). Vancomycin that is in the tubular lumen (either via secretion or free filtration) is then transported across the apical membrane by apical endocytosis through dehydropeptidase (DHP)-1 and megalin. Intracellular vancomycin is aggregated by lysosomes leading to cascade of oxidative stress, complement activation, inflammatory injury, mitochondrial dysfunction, and cellular apoptosis ( 2 ). Preventing vancomycin induced kidney injury is possible via multiple pathways. First, a very clear exposure response relationship exists ( 11 – 16 ). Lower area under the curve exposures result in less toxicity. Second, it is theoretically possible to prevent vancomycin from accumulating intracellularly. We ( 17 ) and others ( 18 , 19 ) have previously demonstrated that administering cilastatin, a putative megalin inhibitor, reduces kidney injury( 6 , 18 ). However, the effect from cilastatin is modest and multiple mechanisms of action such as organic anion transporter inhibitions( 20 , 21 ) complicate mechanistic translation. Megalin is a large glycoprotein expressed on the apical surface of the proximal tubule that mediates intracellular signal transduction and plays an important role in the reabsorption of glomerular-filtered substances ( 18 , 22 ). Demonstrating premise, megalin knock out mouse models have strong efficacy for suppressing drug induced kidney injury ( 23 , 24 ). Vancomycin binds to megalin receptors which causes reuptake into these proximal tubule epithelial cells. Overall, transporter inhibition during active tubular secretion can have varying effects on drug concentrations ( 25 – 27 ). Inhibiting transporters remain an area of study that have potential to improve nephrotoxic drug administration. Based on chemical structure, we hypothesized that protamine might block megalin and decrease vancomycin induced kidney injury. While relatively little information is available on the megalin binding capacity of protamine, protamine shares binding sites with heparin (current target for FDA approved use) and megalin( 28 , 29 ). Supporting this possibility of megalin blockade for the purpose of decreasing cellular accumulation and toxicity, Nagai and colleagues found that protamine inhibited the uptake of gentamicin in cultured opossum kidney cells that expressed megalin and cubilin ( 30 ). Megalin antagonists that block tubular drug reabsorption would be a significant advance as no drugs are approved for this indication. MATERIALS AND METHODS Experimental Design and Animals This animal model study was conducted at Midwestern University in Downers Grove, Illinois with all methods reviewed and approved by MWU Institutional Animal Care and Use Committee (IACUC #3080). Male Sprague Dawley rats (n=19; age 8-10 weeks; 268-304g; Envigo, Indianapolis IN, USA) underwent double jugular catheterization ( 31 ) ( Fig 1a ). Surgery was performed under Ketamine (100mg/kg) and Xyalzine (10mg/kg) anesthesia with Buprenorphine (0.02mg/kg) given post-operatively for pain management. Animals were allowed to recover 4 days before administration of any drug. Animals were housed in metabolic cages starting one day prior to Day 0 with access to food and water ad libitum for the duration of the study ( Fig 1b ). Download figure Open in new tab Figure 1. Experimental design (A) Animals divided into each protocol. (B) Scheme indicating time flow between surgery and when animals are placed into metabolic cages for dosing (PRT, VAN), blood and urine sampling and kidney harvest. Animals were divided into 3 experimental treatment protocols. Using a dedicated jugular vein for dosing, the animals received clinical grade intravenous protamine and/or vancomycin in doses allometrically scaled to humans according to the following protocols: a) Protamine sulfate (1.5mg/kg) and Vancomycin (150mg/kg) (n=6); b) Protamine only (1.5mg/kg) with Saline SHAM (vancomycin) (n=7); or c) Vancomycin only (150mg/kg) with Saline SHAM (protamine) (n=6) ( 32 – 34 ). Saline SHAM was given to match volumes of protamine and vancomycin doses to maintain euvolemia. On Day 0, all animals received only Iohexol (51.8mg/day) intravenously to establish baseline GFR measurements. Drugs were administered as described above by treatment protocols to all groups on Days 1-4. Blood, Urine and Kidney Sampling Blood samples were withdrawn from a designated jugular catheter. Samples were drawn at time 0 (prior to dosing) and at 30 and 60 minutes after Iohexol dosing for [protamine + SSHAM] and [vancomycin + SSHAM] groups. Sampling time points for [protamine + vancomycin] group were 0, 45 and 90 minutes to account for infusion times of both drugs and Iohexol in 6 animals. All blood samples (0.2ml, maximum 3 samples/animal) were taken daily with an equivalent volume of normal saline (NS) injected to maintain euvolemia. Blood samples (with EDTA added) were centrifuged at 16K x g 10 min. and resulting plasma was aliquoted (120 µ l) and stored at −80C for batch analysis later. Urine samples were collected daily, and volumes measured starting from Day 0 until Day 4. Samples were centrifuged at 500g x 10 minutes and the resulting supernatant aliquoted (1.5ml) and stored at - 80C for renal biomarker analysis later. Animals were euthanized (Ketamine/Xylazine) on Day 4 after dosing/sampling for that day with terminal blood and urine collected. Kidneys were harvested, rinsed in cold NS; the right kidney was flash frozen in liquid nitrogen and stored at −80C. The left kidney was rinsed in NS then stored in 10% Buffered Formalin Phosphate and stored at room temperature. Chemicals and Reagents Agents used for treatments were clinical grade Protamine Sulfate Injection (Fresnius Kabi, Lake Zurich, IL USA); clinical grade Vancomycin HCl (Hospira, Lake Forest, IL USA); Omnipaque (iohexol) injection (GE Healthcare, Marlborough, MA USA) and Normal Saline (Veterinary 0.9% sodium chloride injection USP; Abbott Laboratories, North Chicago, IL USA). For liquid chromatography – mass spectroscopy (LCMS) analysis LCMS grade acetonitrile, methanol and formic acid were used (VWR, Radnor, PA USA). Analytical grade iohexol (Sigma Aldrich, St. Louis, MO USA) and isotope Iohexol-d 5 (Cayman Chemicals, Ann Arbor, MI USA) were also used. For the preparation of calibrators for standard curves, frozen aliquots of Na2EDTA treated (anticoagulant) non-medicated, non-immunized plasma pooled from male Sprague Dawley rats (BioIVT, Hicksville, NY USA) were used. For cellular experiments, chemical grade protamine sulfate USP (Product Number P3369, Sigma, St. Louis, MO) was used. Clearance as Calculated by Iohexol In order to describe iohexol clearance a physiological PK model was created with non-linear mixed effects in Monolix (Version 2023R1; Antony, France: Lixoft SAS, 2023). A two-compartment model was used for the samples, with fixed estimates for peripheral compartment volume (V2) and intercompartmental transfer (Q) being derived from the base two-compartment model fitting. Random effects were estimated for clearance (Cl) and central volume (V1). The treatment group was evaluated as a modifier of clearance. To capture daily clearance changes, each experimental day (Monday through Friday) was considered as a separate occasion with time-varying clearance. Clearance was calculated as an occasion every 24 hours to capture the dynamic changes in renal function. EXPERIMENTAL METHODS Urinary Biomarkers Urinary samples were analyzed for KIM-1 using Milliplex MAP Rat Kidney Toxicity Magnetic Bead Panel 1 (EMD Millipore Corporation, Charles, MO USA) according to manufacturer’s directions and previously described ( 32 , 34 , 35 ) Briefly, neat urine aliquots were mixed with monoclonal antibody coated magnetic microbeads (Bead Panel 1) and run on a 96 well plate which also included a standard curve. Biomarker data was acquired, and concentrations were analyzed using Belysa Immunoassay Curve-Fitting Software V1 (MilliporeSigma, Darmstadt, Germany). The amount of urinary KIM-1 excreted was obtained by multiplying the urinary concentration by 24-hour urinary volume. Preparation of Calibration curves in rat plasma Stock solutions of Iohexol and Iohexol-d 5 were prepared using purified water at concentrations of 1mg/ml and 100 µ g/ml respectively. Calibrators for a standard curve were generated by diluting iohexol stock solution with water to produce concentrations ranging between 1.0 and 100 µ g/ml. For each standard curve calibrator, 36 µ l of blank rat plasma was mixed with an iohexol dilution (4 µ l each). Iohexol-d 5 (4 µ l) was then added to each at a final concentration of 10 µ g/ml as the internal standard. Each standard curve calibrator was then mixed with 456 µ l of 0.1% Formic Acid in methanol, vortexed and centrifuged at 16K x g for 10 min. From the resulting supernatant, 100 µ l was transferred to LCMS vials and analyzed. Sample preparation Plasma samples obtained at 30, 45 and 60 min were diluted 1:10 with blank rat plasma with 4µl Iohexol-d 5 added to each. Iohexol-d 5 was also added to remaining rat plasma samples (40µl, undiluted). All samples were then mixed with 0.1% Formic Acid in methanol, vortexed and centrifuged at 16K x g for 10 min. with resulting supernatant transferred to LCMS vials for analysis. LCMS Methods An Agilent 1260 Infinity II series liquid chromatography system was paired with an Ultivo triple quadrupole mass spectrometer (Agilent Technologies, Santa Clara, CA) and used to analyze plasma samples. A Kinetex Polar C18 analytical column was used (2.6µm, 50 x 2.1mm, part number PRD-634714; Phenomenex) and column temperature was maintained at 25°C. Mobile phases were 0.1% formic acid in water (mobile phase A) and acetonitrile (mobile phase B). An isocratic method was used to separate analytes with solvent ratios of 94% mobile phase A – 6% mobile phase B (0 to 0.50 min), 5% mobile phase A – 95% mobile phase B (0.51 to 2.0 min) and 94% mobile phase A – 6% mobile phase B (2.01 to 3.5 min) at a mobile phase flow rate of 0.8 ml/min. Multiple reaction monitoring (MRM) was used for analyte detection monitoring transitions of m/z 821.9 to 803.9 for iohexol and m/z 826.9 to 808.7 for Iohexol-d 5 . Cell Studies OAT1, OAT3, and OCT2 inhibition studies with protamine sulfate were performed by Eurofins Scientific (St. Charles, Missouri, USA) as previously described ( 36 , 37 ). Protamine sulfate was dissolved in DMSO to 1.E-02 M and tested concurrently with p-aminohipurate 10 uM (substrate) for = OAT1, ranitidine 10 uM (substrate) for OAT3 and metformin 100uM (substrate) for OCT2. A time of 30 minutes was used for pre-incubation, followed by 20 minutes of incubation with the substrate. CHOK1 cells were used in OAT1 and 3 experiments, and HEK cells were used in OCT2 experiments. Percent of inhibition was calculated vs. the percent of control. The IC 50 value (concentration causing a half-maximal inhibition of the control value) was determined by non-linear regression analysis of the concentration-response curve from a Hill equation. Experiments were compared to referent IC 50 results on file for OAT1 and 3 using probenicid and for OCT2 using verapamil as exemplar inhibitors. Statistics Urinary KIM-1 concentrations and iohexol clearances over time were compared with a repeated measures mixed model, fit via restricted maximum likelihood to have results comparable to the ANOVA results. An omnibus test, i.e. joint tests (multi degree of freedom) of the interaction and main effects which is similar to the F test in ANOVA, was used initially (STATA 17.0 BE, StataCorp LLC, College Station, Texas). Only models with significant interaction at p<0.05 were selected for post-hoc analysis (i.e., identification of the difference between treatment groups and days). Margins were calculated for a full factorial of the variables, i.e., main effects for each variable and interactions. Referent groups were pre-treatment baseline values and protamine alone as a treatment, except where noted. Secondarily, to remain agnostic to outcome variable relationship over time (and assess treatment groups over time), locally weighted scatterplot smoothing (LOWESS) trendlines with 95% confidence intervals were generated. LOWESS graphs were produced in R version 4.2.2 using ggplot2. No data were excluded as outliers. All tests were two-tailed, a p<0.05 was required for statistical significance. Graphs for cellular studies were generated using GraphPad version 9.3.1 and were fit with a log(inhibitor) vs. normalized response function after log transformation. RESULTS KIM-1 The omnibus test was significant for drug group, day, and the interaction of drug and day (P<0.05). Further evaluation of individual drug groups by day (with Bonferroni corrections) revealed that on day 1 prior to any drug received all groups had similar KIM-1 ( Table 1 ). On day 2 (i.e. 24 hours after drug administration), animals that received vancomycin had significantly increased KIM-1 (24.9 ng/24h, 95% CI 1.87 to 48.0) compared to the protamine alone group as the base. Animals that received protamine did not experience this increase on day 2. On day 3, animals that received protamine had a measured KIM-1 that was numerically similar to animals that received vancomycin only. By day 4, animals that received protamine with their vancomycin had KIM-1 amounts that were elevated compared to protamine alone as a base comparison (KIM-1 29.0 ng/24h, 95% CI 5.0 to 53.0). When comparing each animal group to itself (i.e. change from baseline of day 1), animals that received protamine only did not have a KIM-1 increase over the 4 days (P>0.99) indicating that it was a stable control over the time course of the experiment ( Table 2 ). Animals that received vancomycin alone had elevated KIM-1 on days 2 and 3 (P<0.05) compared to baseline day 1. Animals that received protamine with their vancomycin had KIM-1 elevated compared to baseline day 1 on day 4. View this table: View inline View popup Download powerpoint Table 1. Comparison of KIM-1 across drug treatment groups, by day. View this table: View inline View popup Download powerpoint Table 2. Comparison of KIM-1 across over days within treatment groups with baseline as comparator. Iohexol Clearance The omnibus test was only significant for drug (P=0.047). No statistically observed differences were identified in the Bonferroni corrected results for comparing between drug groups or when comparing clearance change from baseline (P>0.05). Cellular studies Cellular study results are shown in Figure 3 . No substantial inhibition of OAT1, OAT3, or OCT2 was observed. IC 50 values for protamine were 1e-4 M for OAT1 and OAT3 and 4.3e-5 for OCT2. Compared to prototype drugs causing inhibition (i.e. probenecid for OAT1/3 and verapamil for OCT2), IC 50 values were 62.5 and 58.8 times higher for protamine versus probenecid (i.e. IC50s of 1.6E-06 M, 1.7E-06 M) and 5.2 times higher for protamine versus verapamil (IC50 of 8.3E-06 M). DISCUSSION Our results demonstrate that the addition of protamine to vancomycin provides a protective effect against vancomycin AKI and that the effect is likely not driven by OAT1, OAT3, or OCT2 inhibition. These results are important as protamine is currently an FDA approved medication and has the potential to decrease vancomycin AKI, especially when given immediately prior to vancomycin for short vancomycin courses. These results may warrant a clinical study; however, protamine is not the most well tolerated medication and has the liabilities of severe hypotension and anaphylactoid-like reactions ( 38 ). Additional work is needed to confirm the putative mechanism of activity, i.e. megalin blockade. Drug development for medications with fewer adverse effects will be important if mechanism can be clarified. Originally derived from salmon fish sperm (salmine), protamine is a highly positively charged protein consisting of 32 amino acids. Currently, it is widely used as an effective agent to neutralize heparin using electrostatic bonds made between the cationic arginine groups of protamine, and the anionic heparin in a 1:1 ratio. ( 6 ) Specifically, protamine shares binding sites with heparin (current target for FDA approved use) and megalin.( 28 , 29 ) Our preliminary data demonstrates that protamine does not have significant inhibition on OAT1, OAT3, or OCT2 except at extremely high concentrations ( Fig 3 ) and as compared to known inhibitors such as probenecid and verapamil. Protamine enters kidney epithelial cells and localizes in the cytoplasm via receptor mediated endocytosis, putatively through megalin, and has demonstrated prevention of gentamicin accumulation.( 39 ) Gentamicin is known to share a megalin cell entry mechanism with vancomycin.( 18 , 22 , 40 ) Further, rats and humans share identical megalin extracellular motifs/ligand binding sites, making the rat ideal for pre-clinical study.( 41 , 42 ) Our pilot studies with protamine demonstrate a full day of injury prevention and a delay of 72 hours before mean injury for vancomycin+protamine reaches the vancomycin peak seen after 1 day of dosing, though full dose ranging experiments are required to define the dynamic toxicity threshold. Since ∼60% of clinical vancomycin use is ≤2 days,( 43 , 44 ) delaying toxicity will lower DIKI. In humans, vancomycin DIKI (creatinine defined)( 45 ) occurs between an interquartile range of 6-13 days,( 46 ) and creatinine is known to lag behind GFR.( 47 ) Reabsorption of solutes from glomerular filtrate in the kidneys occurs primarily in the proximal renal tubule.( 48 ) Megalin is an endocytic transmembrane protein of the low-density lipoprotein receptor-related protein 2 family (LRP2).( 22 ) It is located in the apical membrane of proximal tubule cells and reabsorbs low molecular weight proteins (LMW) through endocytosis.( 22 ) Beenken et al. used high-resolution cryo-electron microscopy to study LRP2 isolated from mouse kidney.( 49 ) Endosomes with receptor/ligand complex release ligands intracellularly through lysosome interaction, however megalin is recycled back to the apical membrane to be used again. They were able to demonstrate that ligand binding and release is pH dependent within extracellular (pH 7.5) and endosomal (pH 5.2) environments. Structurally, at the cell surface megalin adopts an open conformation exposing the high affinity ligand binding site at pH 7.5. At endosomal pH 5.2, megalin is transformed into a closed conformation with low binding affinity, thus releasing the ligand. The endosome with megalin moves back to the apical membrane where at extracellular pH 7.5 it once again resumes the open, high affinity conformation to bind ligand. Vancomycin is known to bind to megalin and its accumulation within proximal tubule cells is nephrotoxic causing oxidative damage and apoptosis.( 3 ) Vancomycin, a basic compound, is protonated at urinary pH 7.5 and would bind to high affinity sites on Megalin, being released intracellularly in the proximal tubule cell as acidic pH induces the low affinity conformation. The exact mechanism of vancomycin AKI is not entirely known, but current studies state that damage is directly caused by intracellular accumulation of vancomycin ( 7 ) . Vancomycin utilizes drug transporters located on the basolateral membrane of the proximal renal tubule including the organic anion transporter (OAT-1 and OAT-3), as well as the organic cation transporter (OCT-2). From the cell studies completed for our research (see cell study figure), it appears that with protamine, there is little to no inhibition of these transporters at all. With OAT-1 and OAT-3, inhibition does not even reach 50% at 1e-4 molar concentrations of protamine. With OCT-2, there does appear to be very minor inhibition reaching at least 50% at similar concentrations. This likely means that protamine acts as a weak, potentially non-pharmacologically useful substrate and/or inhibitor at incredibly high concentrations. With the evidence that protamine has little to no interactions with the basolateral membrane transporters OAT-1, OAT-3, and OCT-2, the question still remains of how protamine is interacting with vancomycin to reduce AKI – or at the very least delay the onset of AKI when co-administered with vancomycin. It is known from current studies that vancomycin binds directly to the megalin receptor located within the proximal tubule. Hori et al performed a study to evaluate the binding of megalin to vancomycin and cisplatin, as well as aminoglycosides and colistin. They utilized quartz crystal microbalance (QCM) analysis to assess the direct binding of megalin with these drugs, and found that megalin is bound specifically by gentamicin, colistin, vancomycin, and cisplatin. Furthermore, they found that the binding of all above drugs listed is competed by cilastatin. In humans, VAN DIKI (creatinine defined)( 45 ) occurs between an interquartile range of 6-13 days,( 46 ) and creatinine is known to lag behind GFR.( 47 ). Serum creatinine is the most commonly utilized biomarker to classify AKI in patients,( 45 , 50 – 52 ) yet, creatinine is non-sensitive, non-specific, and slowly reactive to kidney function as compared to GFR.( 53 ) GFR can drop 50% before changes in SCr are detected.( 54 – 56 ) As such, acute injuries can take a median of 6 days to be detectable with creatinine alone ( 57 ). Therefore this study focused on the pre-clinical urinary biomarker, KIM-1, that has been shown as sensitive and specific for vancomycin kidney injury.( 6 , 58 ) Vancomycin induced kidney injury with urinary KIM-1 in the rat model is detectable within a single calendar day ( 6 , 32 ) and the model links to human outcomes.( 14 ) Protamine demonstrates a full day of injury prevention and a delay of 72 hours before mean injury for vancomycin + protamine reaches the vancomycin injury peak seen after 1 day of dosing ( Fig 2 ). Since ∼60% of clinical VAN use is ≤2 days,( 43 , 44 ) delaying toxicity with an adjunct like protamine could lower vancomycin induced kidney injury. Download figure Open in new tab Figure 2 Urinary KIM-1 (ng/24) for each study group over study days, shown as a violin plot (A) and individual values with 95% CI (B) Download figure Open in new tab Figure 3. Cellular inhibition studies with protamine, shown in Molar (M) concentrations. Download figure Open in new tab Figure 4. Calculated Iohexol clearance for each treatment group that received iohexol. CONCLUSION Protamine, when added to vancomycin therapy, delays vancomycin induced kidney injury as defined by urinary KIM-1 in the rat model by one to three days. Protamine putatively acts through blockade of megalin and does not appear to have significant inhibition on OAT1, OAT3, or OCT2. Since protamine is an approved FDA medication, it has clinical potential as a therapeutic to reduce vancomycin related kidney injury; however, greater utility may be found by pursuing compounds with fewer adverse event liabilities. Footnotes ↵ † This manuscript is dedicated to Dr. Patti Engel who was deceased during the writing of this manuscript. Her meticulous notes allow for the report of data here. ↵ * Affiliation at time of study conduct. REFERENCES 1. ↵ Magill SS , O’Leary E , Ray SM , Kainer MA , Evans C , Bamberg WM , Johnston H , Janelle SJ , Oyewumi T , Lynfield R , Rainbow J , Warnke L , Nadle J , Thompson DL , Sharmin S , Pierce R , Zhang AY , Ocampo V , Maloney M , Greissman S , Wilson LE , Dumyati G , Edwards JR , Team EIPHPS . 2020 . Antimicrobial Use in US Hospitals: Comparison of Results From Emerging Infections Program Prevalence Surveys, 2015 and 2011 . Clinical Infectious Diseases 72 : 1784 – 1792 . OpenUrl 2. ↵ Wilhelm MP . 1991 . Vancomycin . Mayo Clin Proc 66 : 1165 – 70 . OpenUrl CrossRef PubMed Web of Science 3. ↵ Kan WC , Chen YC , Wu VC , Shiao CC . 2022 . Vancomycin-Associated Acute Kidney Injury: A Narrative Review from Pathophysiology to Clinical Application . Int J Mol Sci 23 . 4. ↵ Sinha Ray A , Haikal A , Hammoud KA , Yu ASL . 2016 . Vancomycin and the Risk of AKI: A Systematic Review and Meta-Analysis . Clin J Am Soc Nephrol 11 : 2132 – 2140 . OpenUrl Abstract / FREE Full Text 5. ↵ Luque Y , Louis K , Jouanneau C , Placier S , Esteve E , Bazin D , Rondeau E , Letavernier E , Wolfromm A , Gosset C , Boueilh A , Burbach M , Frere P , Verpont MC , Vandermeersch S , Langui D , Daudon M , Frochot V , Mesnard L . 2017 . Vancomycin-Associated Cast Nephropathy . J Am Soc Nephrol 28 : 1723 – 1728 . OpenUrl Abstract / FREE Full Text 6. ↵ Pais GM , Liu J , Zepcan S , Avedissian SN , Rhodes NJ , Downes KJ , Moorthy GS , Scheetz MH . 2020 . Vancomycin-Induced Kidney Injury: Animal Models of Toxicodynamics, Mechanisms of Injury, Human Translation, and Potential Strategies for Prevention . Pharmacotherapy 40 : 438 – 454 . OpenUrl CrossRef 7. ↵ Filippone EJ , Kraft WK , Farber JL . 2017 . The Nephrotoxicity of Vancomycin . Clin Pharmacol Ther 102 : 459 – 469 . OpenUrl CrossRef PubMed 8. ↵ Marre R , Schulz E , Anders T , Sack K . 1984 . Renal tolerance and pharmacokinetics of vancomycin in rats . J Antimicrob Chemother 14 : 253 – 60 . OpenUrl CrossRef PubMed Web of Science 9. ↵ Nishino Y , Takemura S , Minamiyama Y , Hirohashi K , Ogino T , Inoue M , Okada S , Kinoshita H . 2003 . Targeting superoxide dismutase to renal proximal tubule cells attenuates vancomycin-induced nephrotoxicity in rats . Free Radic Res 37 : 373 – 9 . OpenUrl CrossRef PubMed Web of Science 10. ↵ Fujiwara K , Yoshizaki Y , Shin M , Miyazaki T , Saita T , Nagata S . 2012 . Immunocytochemistry for vancomycin using a monoclonal antibody that reveals accumulation of the drug in rat kidney and liver . Antimicrob Agents Chemother 56 : 5883 – 91 . OpenUrl Abstract / FREE Full Text 11. ↵ Liu J , Tong SYC , Davis JS , Rhodes NJ , Scheetz MH , Group CS . 2020 . Vancomycin Exposure and Acute Kidney Injury Outcome: A Snapshot From the CAMERA2 Study . Open Forum Infect Dis 7 : ofaa538 . OpenUrl 12. Lodise TP , Rosenkranz SL , Finnemeyer M , Huvane J , Pereira A , Sims M , Zervos MJ , Creech CB , Patel PC , Keefer M , Riska P , Silveira FP , Scheetz M , Wunderink RG , Rodriguez M , Schrank J , Bleasdale SC , Schultz S , Barron M , Stapleton A , Chambers H , Fowler V , Holland TL . 2017 . The Emperor’s New Clothes: Prospective Observational Evaluation of the Association between the Day 2 Vancomycin Exposure and Failure Rates among Adult Hospitalized Patients with MRSA Bloodstream Infections (PROVIDE) . Open Forum Infectious Diseases 4 : S30 – S31 . OpenUrl 13. Lodise TP , Scheetz M , Carreno JJ , Chambers H , Fowler V , Jr. , Holland TL . 2022 . Associations Between Vancomycin Exposure and Acute Kidney Injury Within the Recommended Area Under the Curve Therapeutic Exposure Range Among Patients With Methicillin-Resistant Staphylococcus aureus Bloodstream Infections . Open Forum Infect Dis 9 : ofab651 . OpenUrl 14. ↵ Scheetz MH , Pais GM , Lodise TP , Tong SYC , Davis JS , O’Donnell JN , Liu J , Neely M , Prozialeck WC , Lamar PC , Rhodes NJ , Holland T , Avedissian SN . 2021 . Of Rats and Men: a Translational Model To Understand Vancomycin Pharmacokinetic/Toxicodynamic Relationships . Antimicrob Agents Chemother 65 : e0106021 . OpenUrl 15. Avedissian SN , Pais G , Liu J , O’Donnell JN , Lodise TP , Neely M , Prozialeck WC , Lamar PC , Becher L , Scheetz MH . 2021 . The Pharmacodynamic-Toxicodynamic Relationship of AUC and C(max) in Vancomycin-Induced Kidney Injury in an Animal Model . Antimicrob Agents Chemother 65 . 16. ↵ Avedissian SN , Pais GM , O’Donnell JN , Lodise TP , Liu J , Prozialeck WC , Joshi MD , Lamar PC , Becher L , Gulati A , Hope W , Scheetz MH . 2019 . Twenty-four hour pharmacokinetic relationships for intravenous vancomycin and novel urinary biomarkers of acute kidney injury in a rat model . J Antimicrob Chemother 74 : 2326 – 2334 . OpenUrl CrossRef 17. ↵ Pais GM , Marianski S , Valdez K , Melicor RP , Liu J , Rohani R , Chang J , Tong SYC , Davis JS , Scheetz MH . 2024 . Flucloxacillin worsens while imipenem-cilastatin protects against vancomycin-induced kidney injury in a translational rat model . Br J Pharmacol 181 : 670 – 680 . OpenUrl 18. ↵ Hori Y , Aoki N , Kuwahara S , Hosojima M , Kaseda R , Goto S , Iida T , De S , Kabasawa H , Kaneko R , Aoki H , Tanabe Y , Kagamu H , Narita I , Kikuchi T , Saito A. 2017 . Megalin Blockade with Cilastatin Suppresses Drug-Induced Nephrotoxicity . J Am Soc Nephrol 28 : 1783 – 1791 . OpenUrl Abstract / FREE Full Text 19. ↵ He M , Souza E , Matvekas A , Crass RL , Pai MP . 2021 . Alteration in Acute Kidney Injury Potential with the Combination of Vancomycin and Imipenem-Cilastatin/Relebactam or Piperacillin/Tazobactam in a Preclinical Model . Antimicrob Agents Chemother 65 . 20. ↵ Huo X , Meng Q , Wang C , Zhu Y , Liu Z , Ma X , Ma X , Peng J , Sun H , Liu K . 2019 . Cilastatin protects against imipenem-induced nephrotoxicity via inhibition of renal organic anion transporters (OATs) . Acta Pharm Sin B 9 : 986 – 996 . OpenUrl 21. ↵ Zhu Y , Huo X , Wang C , Meng Q , Liu Z , Sun H , Tan A , Ma X , Peng J , Liu K . 2020 . Organic anion transporters also mediate the drug-drug interaction between imipenem and cilastatin . Asian J Pharm Sci 15 : 252 – 263 . OpenUrl 22. ↵ Goto S , Hosojima M , Kabasawa H , Saito A . 2023 . The endocytosis receptor megalin: From bench to bedside . Int J Biochem Cell Biol 157 : 106393 . OpenUrl 23. ↵ Nielsen R , Christensen EI , Birn H . 2016 . Megalin and cubilin in proximal tubule protein reabsorption: from experimental models to human disease . Kidney Int 89 : 58 – 67 . OpenUrl CrossRef PubMed 24. ↵ Schmitz C , Hilpert J , Jacobsen C , Boensch C , Christensen EI , Luft FC , Willnow TE . 2002 . Megalin deficiency offers protection from renal aminoglycoside accumulation . J Biol Chem 277 : 618 – 22 . OpenUrl Abstract / FREE Full Text 25. ↵ Lepist EI , Ray AS . 2016 . Renal Transporter-Mediated Drug-Drug Interactions: Are They Clinically Relevant? J Clin Pharmacol 56 Suppl 7 : S73 – 81 . OpenUrl 26. Ivanyuk A , Livio F , Biollaz J , Buclin T . 2017 . Renal Drug Transporters and Drug Interactions . Clin Pharmacokinet 56 : 825 – 892 . OpenUrl CrossRef PubMed 27. ↵ Nakada T , Kudo T , Ito K . 2023 . Quantitative Consideration of Clinical Increases in Serum Creatinine Caused by Renal Transporter Inhibition . Drug Metab Dispos 51 : 1114 – 1126 . OpenUrl Abstract / FREE Full Text 28. ↵ Marino M , Friedlander JA , McCluskey RT , Andrews D . 1999 . Identification of a heparin-binding region of rat thyroglobulin involved in megalin binding . J Biol Chem 274 : 30377 – 86 . OpenUrl Abstract / FREE Full Text 29. ↵ Marino M , Zheng G , McCluskey RT . 1999 . Megalin (gp330) is an endocytic receptor for thyroglobulin on cultured fisher rat thyroid cells . J Biol Chem 274 : 12898 – 904 . OpenUrl Abstract / FREE Full Text 30. ↵ Nagai J , Komeda T , Katagiri Y , Yumoto R , Takano M . 2013 . Characterization of protamine uptake by opossum kidney epithelial cells . Biol Pharm Bull 36 : 1942 – 9 . OpenUrl 31. ↵ Pais GM , Chang J , Liu J , Scheetz MH . 2022 . A translational rat model to assess glomerular function changes with vancomycin . Int J Antimicrob Agents 59 : 106583 . OpenUrl 32. ↵ Pais GM , Liu J , Avedissian SN , Hiner D , Xanthos T , Chalkias A , d’Aloja E , Locci E , Gilchrist A , Prozialeck WC , Rhodes NJ , Lodise TP , Fitzgerald JC , Downes KJ , Zuppa AF , Scheetz MH. 2020 . Lack of synergistic nephrotoxicity between vancomycin and piperacillin/tazobactam in a rat model and a confirmatory cellular model . J Antimicrob Chemother 75 : 1228 – 1236 . OpenUrl CrossRef 33. Chang J , Pais GM , Engel PL , Klimek P , Marianski S , Valdez K , Scheetz MH . 2023 . Impact of Vancomycin Loading Doses and Dose Escalation on Glomerular Function and Kidney Injury Biomarkers in a Translational Rat Model . Antimicrob Agents Chemother 67 : e0127622 . OpenUrl 34. ↵ Rhodes NJ , Prozialeck WC , Lodise TP , Venkatesan N , O’Donnell JN , Pais G , Cluff C , Lamar PC , Neely MN , Gulati A , Scheetz MH . 2016 . Evaluation of Vancomycin Exposures Associated with Elevations in Novel Urinary Biomarkers of Acute Kidney Injury in Vancomycin-Treated Rats . Antimicrob Agents Chemother 60 : 5742 – 51 . OpenUrl Abstract / FREE Full Text 35. ↵ Prozialeck WC , Edwards JR , Lamar PC , Liu J , Vaidya VS , Bonventre JV . 2009 . Expression of kidney injury molecule-1 (Kim-1) in relation to necrosis and apoptosis during the early stages of Cd-induced proximal tubule injury . Toxicol Appl Pharmacol 238 : 306 – 14 . OpenUrl CrossRef PubMed 36. ↵ Otsuka M , Matsumoto T , Morimoto R , Arioka S , Omote H , Moriyama Y . 2005 . A human transporter protein that mediates the final excretion step for toxic organic cations . Proc Natl Acad Sci U S A 102 : 17923 – 8 . OpenUrl Abstract / FREE Full Text 37. ↵ Antonescu IE , Karlgren M , Pedersen ML , Simoff I , Bergström CAS , Neuhoff S , Artursson P , Steffansen B , Nielsen CU . 2020 . Acamprosate Is a Substrate of the Human Organic Anion Transporter (OAT) 1 without OAT3 Inhibitory Properties: Implications for Renal Acamprosate Secretion and Drug–Drug Interactions . Pharmaceutics 12 : 390 . OpenUrl 38. ↵ Boer C , Meesters MI , Veerhoek D , Vonk ABA . 2018 . Anticoagulant and side-effects of protamine in cardiac surgery: a narrative review . British Journal of Anaesthesia 120 : 914 – 927 . OpenUrl 39. ↵ Nagai J , Komeda T , Yumoto R , Takano M . 2013 . Effect of protamine on the accumulation of gentamicin in opossum kidney epithelial cells . J Pharm Pharmacol 65 : 441 – 6 . OpenUrl 40. ↵ Dagil R , O’Shea C , Nykjaer A , Bonvin AM , Kragelund BB . 2013 . Gentamicin binds to the megalin receptor as a competitive inhibitor using the common ligand binding motif of complement type repeats: insight from the nmr structure of the 10th complement type repeat domain alone and in complex with gentamicin . J Biol Chem 288 : 4424 – 35 . OpenUrl Abstract / FREE Full Text 41. ↵ Hjalm G , Murray E , Crumley G , Harazim W , Lundgren S , Onyango I , Ek B , Larsson M , Juhlin C , Hellman P , Davis H , Akerstrom G , Rask L , Morse B . 1996 . Cloning and sequencing of human gp330, a Ca(2+)-binding receptor with potential intracellular signaling properties . Eur J Biochem 239 : 132 – 7 . OpenUrl CrossRef PubMed Web of Science 42. ↵ Awdishu L , Joy MS . 2023 . Endocytosis and Nephrotoxicity—It’s a RAP! Kidney 360 4 . OpenUrl 43. ↵ Kelesidis T , Braykov N , Uslan DZ , Morgan DJ , Gandra S , Johannsson B , Schweizer ML , Weisenberg SA , Young H , Cantey J , Perencevich E , Septimus E , Srinivasan A , Laxminarayan R . 2016 . Indications and Types of Antibiotic Agents Used in 6 Acute Care Hospitals, 2009-2010: A Pragmatic Retrospective Observational Study . Infect Control Hosp Epidemiol 37 : 70 – 9 . OpenUrl CrossRef PubMed 44. ↵ Chang J , Liu J , Kaye KS , Scheetz MH . 2020 . Vancomycin Duration of Therapy Can Inform the Need for Area Under the Curve Monitoring . Clinical Infectious Diseases doi: 10.1093/cid/ciaa1849 . OpenUrl CrossRef 45. ↵ Anonymous . 2012 . Kidney Disease: Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury . Kidney Int Suppl 2 : 1 – 138 . OpenUrl CrossRef PubMed 46. ↵ Lodise TP , Scheetz M , Carreno JJ , Chambers H , Fowler V , Jr . , Holland TL , Group ftARL . 2022 . Associations Between Vancomycin Exposure and Acute Kidney Injury Within the Recommended Area Under the Curve Therapeutic Exposure Range Among Patients With Methicillin-Resistant Staphylococcus aureus Bloodstream Infections . Open Forum Infectious Diseases 9 . 47. ↵ Waikar SS , Bonventre JV . 2009 . Creatinine kinetics and the definition of acute kidney injury . J Am Soc Nephrol 20 : 672 – 9 . OpenUrl Abstract / FREE Full Text 48. ↵ Bailey M , Unwin R . 2019 . Renal Physiology , p 14 – 28 . In Feehally J , Floege Jr . , Tonelli M , Johnson RJ (ed), Comprehensive clinical nephrology , Sixth edition ed. Elsevier , Edinburgh . 49. ↵ Beenken A , Cerutti G , Brasch J , Guo Y , Sheng Z , Erdjument-Bromage H , Aziz Z , Robbins-Juarez SY , Chavez EY , Ahlsen G , Katsamba PS , Neubert TA , Fitzpatrick AWP , Barasch J , Shapiro L . 2023 . Structures of LRP2 reveal a molecular machine for endocytosis . Cell 186 : 821 – 836 e13. OpenUrl CrossRef 50. ↵ Mehta RL , Kellum JA , Shah SV , Molitoris BA , Ronco C , Warnock DG , Levin A , Acute Kidney Injury N . 2007 . Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury . Crit Care 11 : R31 . OpenUrl CrossRef PubMed 51. Bellomo R , Ronco C , Kellum JA , Mehta RL , Palevsky P , Acute Dialysis Quality Initiative w . 2004 . Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group . Crit Care 8 : R204 – 12 . OpenUrl CrossRef PubMed Web of Science 52. ↵ Makris K , Spanou L . 2016 . Acute Kidney Injury: Definition, Pathophysiology and Clinical Phenotypes . Clin Biochem Rev 37 : 85 – 98 . OpenUrl PubMed 53. ↵ Waikar SS , Betensky RA , Emerson SC , Bonventre JV . 2012 . Imperfect gold standards for kidney injury biomarker evaluation . J Am Soc Nephrol 23 : 13 – 21 . OpenUrl Abstract / FREE Full Text 54. ↵ Duarte CG , Preuss HG . 1993 . Assessment of renal function--glomerular and tubular . Clin Lab Med 13 : 33 – 52 . OpenUrl CrossRef PubMed Web of Science 55. Shemesh O , Golbetz H , Kriss JP , Myers BD . 1985 . Limitations of creatinine as a filtration marker in glomerulopathic patients . Kidney Int 28 : 830 – 8 . OpenUrl CrossRef PubMed Web of Science 56. ↵ Swan SK . 1997 . The search continues--an ideal marker of GFR . Clin Chem 43 : 913 – 4 . OpenUrl FREE Full Text 57. ↵ Lodise TP , Patel N , Lomaestro BM , Rodvold KA , Drusano GL . 2009 . Relationship between Initial Vancomycin Concentration-Time Profile and Nephrotoxicity among Hospitalized Patients . Clinical Infectious Diseases 49 : 507 – 514 . OpenUrl CrossRef PubMed Web of Science 58. ↵ Pais GM , Avedissian SN , O’Donnell JN , Rhodes NJ , Lodise TP , Prozialeck WC , Lamar PC , Cluff C , Gulati A , Fitzgerald JC , Downes KJ , Zuppa AF , Scheetz MH . 2019 . Comparative Performance of Urinary Biomarkers for Vancomycin-Induced Kidney Injury According to Timeline of Injury . Antimicrob Agents Chemother 63 . View the discussion thread. Back to top Previous Next Posted August 15, 2024. Download PDF Email Thank you for your interest in spreading the word about bioRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. You are going to email the following Protamine protects against Vancomycin Induced Kidney Injury Message Subject (Your Name) has forwarded a page to you from bioRxiv Message Body (Your Name) thought you would like to see this page from the bioRxiv website. Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Share Protamine protects against Vancomycin Induced Kidney Injury Justin Shiau , Patti Engel , Mark Olsen , Gwendolyn Pais , Jack Chang , Marc H. Scheetz bioRxiv 2024.08.12.607677; doi: https://doi.org/10.1101/2024.08.12.607677 Share This Article: Copy Citation Tools Protamine protects against Vancomycin Induced Kidney Injury Justin Shiau , Patti Engel , Mark Olsen , Gwendolyn Pais , Jack Chang , Marc H. Scheetz bioRxiv 2024.08.12.607677; doi: https://doi.org/10.1101/2024.08.12.607677 Citation Manager Formats BibTeX Bookends EasyBib EndNote (tagged) EndNote 8 (xml) Medlars Mendeley Papers RefWorks Tagged Ref Manager RIS Zotero Tweet Widget Facebook Like Google Plus One Subject Area Pharmacology and Toxicology Subject Areas All Articles Animal Behavior and Cognition (7644) Biochemistry (17728) Bioengineering (13916) Bioinformatics (42037) Biophysics (21489) Cancer Biology (18637) Cell Biology (25553) Clinical Trials (138) Developmental Biology (13401) Ecology (19941) Epidemiology (2067) Evolutionary Biology (24367) Genetics (15622) Genomics (22547) Immunology (17764) Microbiology (40475) Molecular Biology (17208) Neuroscience (88747) Paleontology (667) Pathology (2842) Pharmacology and Toxicology (4834) Physiology (7659) Plant Biology (15175) Scientific Communication and Education (2047) Synthetic Biology (4304) Systems Biology (9835) Zoology (2272)