Urinary Biomarkers Of Kidney Injury Research Articles

Serum and urinary biomarkers of vancomycin-induced acute kidney injury: A prospective, observational analysis.

Vancomycin, a first-line drug for treating methicillin-resistant Staphylococcus aureus infections, is associated with acute kidney injury (AKI). This study involved an evaluation of biomarkers for AKI detection and their comparison with traditional serum creatinine (SCr). We prospectively enrolled patients scheduled to receive intravenous vancomycin for methicillin-resistant S aureus infection. Blood samples for pharmacokinetic assessment and SCr and cystatin C (CysC) measurements were collected at baseline and on days 3, 7, and 10 from the initiation of vancomycin administration (day 1). Urinary biomarkers, including kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin, and clusterin, were collected from days 1 to 7 and adjusted for urinary creatinine levels. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Of the 42 patients, 6 experienced vancomycin-induced AKI. On day 7, the change from baseline eGFR using CysC (ΔeGFRCysC) showed a stronger correlation with vancomycin area under the curve (r = -0.634, P < .001) than that using SCr (ΔeGFRSCr; r = -0.437, P = .020). ΔeGFRSCr showed no significant correlation with vancomycin pharmacokinetic in patients with body mass index ≥23. The median (interquartile range) level of KIM-1 (μg/mg) was significantly higher in the AKI group (0.006 [0.005-0.008]) than in the non-AKI group (0.004 [0.001-0.005]) (P = .039, Mann-Whitney U test), with area under the receiver operating characteristic curve (95% confidence interval) of 0.788 (0.587-0.990). Serum CysC, particularly in overweight individuals or those with obesity, along with urinary KIM-1 are important predictors of vancomycin-induced AKI. These results may aid in selecting better biomarkers than traditional SCr for detecting vancomycin-induced AKI.

Actin Dysregulation Mediates Nephrotoxicity of Cassiae Semen Aqueous Extracts.

Cassiae semen, commonly consumed as roasted tea, has been widely used for both medicinal purposes and dietary supplements. In this study, we investigated the nephrotoxic effects and underlying mechanisms of Cassiae semen aqueous extracts (CSAEs) using computational and animal models. Both male and female Sprague Dawley rats were treated with 4.73-47.30 g/kg (body weight) of CSAEs by oral gavage twice a day for 7-28 days. We found that serum and urinary biomarkers of kidney injury and kidney coefficients were increased in a dose-dependent manner, and were accompanied by morphological alterations in the kidneys of CSAEs-treated rats. Computational and molecular docking approaches predicted that the three most abundant components of CSAEs-obtusifolin, aurantio-obtusin, and obtusin-exhibited strong affinity for the binding of F-actin, ROCK1, and Rac1, and the RhoA-ROCK pathway was identified as the most likely regulatory mechanism mediating the nephrotoxicity of CSAEs. Consistently, immunofluorescence staining revealed F-actin and cytoskeleton were frequently disturbed in renal cells and brush borders at high doses of CSAEs. Results from gene expression analyses confirmed that CSAEs suppressed the key proteins in the RhoA-ROCK signaling pathway and consequently the expression of F-actin and its stabilization genes. In summary, our findings suggest that Cassiae semen can depolymerize and destabilize actin cytoskeleton by inhibition of the RhoA-ROCK pathway and/or direct binding to F-actin, leading to nephrotoxicity. The consumption of Cassiae semen as a supplement and medicine warrants attention.

A novel real-time model for predicting acute kidney injury in critically ill patients within 12 hours.

A major challenge in prevention and early treatment of acute kidney injury (AKI) is the lack of high-performance predictors in critically ill patients. Therefore, we innovatively constructed U-AKIpredTM for predicting AKI in critically ill patients within 12h of panel measurement. The prospective cohort study included 680 patients in the training set and 249 patients in the validation set. After performing inclusion and exclusion criteria, 417 patients were enrolled in the training set and 164 patients were enrolled in the validation set finally. AKI was diagnosed by Kidney Disease Improving Global Outcomes (KDIGO) criteria. Twelve urinary kidney injury biomarkers (mALB, IgG, TRF, α1MG, NAG, NGAL, KIM-1, L-FABP, TIMP2, IGFBP7, CAF22 and IL-18) exhibited good predictive performance for AKI within 12h in critically ill patients. U-AKIpredTM, combined with three crucial biomarkers (α1MG, L-FABP and IGFBP7) by multivariate logistic regression analysis, exhibited better predictive performance for AKI in critically ill patients within 12h than the other twelve kidney injury biomarkers. The area under the curve (AUC) of the U-AKIpredTM, as a predictor of AKI within 12h, was 0.802 (95% CI: 0.771-0.833, P<0.001) in the training set and 0.844 (95% CI: 0.792-0.896, P<0.001) in validation cohort. A nomogram based on the results of the training and validation sets of U-AKIpredTM was developed which showed optimal predictive performance for AKI. The fitting effect and prediction accuracy of U-AKIpredTM was evaluated by multiple statistical indicators. To provide a more flexible predictive tool, the dynamic nomogram (https://www.xsmartanalysis.com/model/U-AKIpredTM) was constructed using a web-calculator. Decision curve analysis (DCA) and a clinical impact curve were used to reveal that U-AKIpredTM with the three crucial biomarkers had a higher net benefit than these twelve kidney injury biomarkers respectively. The net reclassification index (NRI) and integrated discrimination index (IDI) were used to improve the significant risk reclassification of AKI compared with the 12 kidney injury biomarkers. The predictive efficiency of U-AKIpredTM was better than the NephroCheck® when testing for AKI and severe AKI. U-AKIpredTM is an excellent predictive model of AKI in critically ill patients within 12h and would assist clinicians in identifying those at high risk of AKI.

#1868 Dapagliflozin reduces urinary kidney injury biomarkers in chronic kidney disease irrespective of albuminuria level

Abstract Background and Aims The beneficial effects of Sodium-Glucose Cotransporter 2(SGLT2) inhibitor in patients with chronic kidney disease (CKD) with low albuminuria levels have not been established. In this study, we aimed to compare the effects of dapagliflozin on kidney injury biomarkers in patients with CKD stratified by albuminuria level. Method We prospectively enrolled healthy volunteers (HVs) (n = 20) and patients with CKD (n = 54) with and without diabetes mellitus (DM). Patients with CKD were divided into two subgroups by age- and sex-matched according to urinary albumin-creatinine ratio (uACR) levels (&amp;lt;300 mg/g and ≥300 mg/g). The CKD group received dapagliflozin 10 mg per day. Urine samples were collected before treatment and after 3 months and 6 months of dapagliflozin. Urinary kidney injury molecule-1 (KIM-1), interleukin-1β (IL-1β), and mitochondrial DNA nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND1) copy number were measured. Results The estimated glomerular filtration rate (eGFR) of patients with CKD was lower than that of HVs (p &amp;lt; 0.001). During the study period, eGFR decreased and uACR did not change in the CKD group. Kidney injury markers were significantly elevated in patients with CKD compared with those in HVs. Dapagliflozin reduced urinary KIM-1, IL-1β and mtDNA copy number in patients with CKD after 6 months of treatment. In further, the levels of urinary KIM-1 and IL-1β, patients with CKD decreased after 6 months of dapagliflozin treatment regardless of albuminuria level. Conclusion In this study, dapagliflozin reduced urinary kidney injury biomarkers in patients with CKD, regardless of albuminuria level. These findings suggest that SGLT2i may also attenuate the progression of low albuminuric CKD.

One Novel Urinary Biomarkers of Acute Kidney Injury in Patients After Allogeneic Hematopoetic Stem Cell Transplantation

Hematopoietic stem cell transplantation could be complicated by acute kidney injury and chronic kidney disease. It may be due to either previous chemotherapy or exposure to a variety of nephrotoxic drug or other causes. The aim of the study was to assess biomarkers of kidney injury in patients at least 3 months after hematopoetic stem cell transplantation (HSCT) under ambulatory care of the Hematology, Transplantation and Internal Medicine Department. We studied 80 prevalent patients after allogeneic HSCT and 32 healthy volunteers to obtain normal ranges of biomarkers. In this cross-sectional study we assessed retinol-binding protein 4 (RBP4), a biomarker of kidney injury in urine using commercially available assays. It was significantly higher in patients after HSCT when compared to healthy volunteers. When we divided patients according to kidney function (below and over 60 mL/min/1.72 m2), we found that the concentration of RBP4 was significantly higher in 23 patients with chronic kidney disease stage 3 compared to patients with estimated glomerular filtration (eGFR) over 60 mL/min/1.72 m2. In univariate correlations RBP4 was positively related to serum creatinine (r = 0.34, P < .01) and inversely to eGFR (r = −0.20, P < .05). Patients after allogeneic HSCT despite normal or near normal kidney function show evidence of kidney injury.

Systematic Review of Kidney Injury Biomarkers for the Evaluation of CKD of Uncertain Etiology

IntroductionChronic kidney disease of uncertain etiology (CKDu) is an incompletely defined phenotype of CKD affecting young individuals mostly in agricultural communities in Central America and South Asia. CKDu is a diagnosis of exclusion made in individuals from endemic regions. MethodsWe conducted a systematic review of the primary literature on urinary and plasma kidney injury biomarkers measured in the setting of CKDu (through February 2023). Literature was identified via a Web of Science search and hand search of the references of previously identified literature. Search terms included “CKDu,” “Mesoamerican Nephropathy,” “CKD of unknown etiology,” “Chronic Interstitial Nephritis in Agricultural Communities,” “biomarker,” “urin*,” and/or “plasma.” ResultsA total of 25 papers were included. The two most frequently measured biomarkers were urinary kidney injury molecule-1 and urinary neutrophil gelatinase-associated lipocalin. There was substantial variability in study design, laboratory assay methods, and statistical methodology which prohibited meta-analysis. ConclusionBiomarkers that identify tubulointerstitial disease early and accurately may substantially accelerate progress in the study of CKDu and facilitate public health approaches that eventually lead to its prevention and elimination. To date, the literature is limited by relatively small sample sizes and methodological limitations which should be addressed in future studies.

Dapagliflozin Reduces Urinary Kidney Injury Biomarkers in Chronic Kidney Disease Irrespective of Albuminuria Level.

The beneficial effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with chronic kidney disease (CKD) with low albuminuria levels have not been established. This study aimed to compare the effects of dapagliflozin on kidney injury biomarkers in patients with CKD stratified by albuminuria level. We prospectively enrolled healthy volunteers (HVs; n = 20) and patients with CKD (n = 54) with and without diabetes mellitus. Patients with CKD were divided into two age-matched and sex-matched subgroups according to urinary albumin-creatinine ratio (uACR) levels (<300 mg/g and ≥300 mg/g). The CKD group received dapagliflozin (10 mg/day). Urine samples were collected before treatment and after 3 and 6 months of dapagliflozin. Urinary kidney injury molecule-1 (KIM-1), interleukin-1β (IL-1β), and mitochondrial DNA nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND1) copy number were measured. The estimated glomerular filtration rate (eGFR) of patients with CKD was lower than that of HVs (P < 0.001). During the study period, eGFR decreased and uACR did not change in the CKD group. Kidney injury markers were significantly elevated in patients with CKD compared with those in HVs. Dapagliflozin reduced urinary KIM-1, IL-1β, and mtDNA copy number in patients with CKD after 6 months of treatment. In further, the levels of urinary KIM-1 and IL-1β, patients with CKD decreased after 6 months of dapagliflozin treatment regardless of albuminuria level. Dapagliflozin reduced urinary kidney injury biomarkers in patients with CKD, regardless of albuminuria level. These findings suggest that SGLT2 inhibitors may also attenuate the progression of low albuminuric CKD.

Hepatorenal Syndrome Type 1: Diagnosis and Treatment.

Hepatorenal syndrome (HRS)is a feared complication in patients with advanced cirrhosis and is associated with significant morbidity and mortality. While recognized as a distinct physiologic condition for well over one hundred years, a lack of objective diagnostic tests has made the diagnosis one of exclusion. Since 1979, multiple sets of diagnostic criteria have been proposed. Though varying in detail, the principal intent of these criteria is to identify patients with severe, functional acute kidney injury that is unresponsive to volume resuscitation and exclude those with structural injury. However, accurate differential diagnosis remains challenging. Recently, multiple urinary biomarkers of kidney injury, including neutrophil gelatinase-associated lipocalin, have been studied as a means of objectively phenotyping etiologies of acute kidney injury in patients with cirrhosis. Along with markers reflecting tubular functional integrity, includingthe fractional excretion of sodium, injury markers will likely be incorporated into future diagnostic criteria. Making an accurate diagnosis is critical, as therapeutic options exist for HRS but must be given in a timely manner and only to those patients likely to benefit. Terlipressin, an analog of vasopressin, is the first line of therapy for HRS in much of the world and has recently been approved for use in the United States. Significant questions remain regarding the optimal dosing strategy, metrics for titration, and the potential role of point-of-care ultrasound to help guide concurrent albumin administration.

Impact of humanized vancomycin infusion on kidney function and kidney injury in a translational rat model

Allometric dose scaling aims to create isometric exposures between animals and humans and is often employed in preclinical pharmacokinetic/pharmacodynamic models. Bolus-administration with allometric scaling is the most simple and commonly used strategy in pre-clinical kidney injury studies; however, it is possible to humanize drug exposures. Currently, it is unknown if dose-matched, bolus-administration with allometric scaling results in similar outcomes compared to humanized infusions in the vancomycin induced kidney injury model. We utilized a preclinical Sprague-Dawley rat model to compare traditional allometrically-scaled, dose-matched, bolus-administration of vancomycin to an infusion-pump controlled, humanized infusion scheme to assess for differences in iohexol-measured kidney function and urinary kidney injury biomarkers. Following 24 h of vancomycin administration, rats in the humanized infusion group had equivalent area under the curve exposures to animals in the dose-matched bolus group (93.7 mg·h/L [IQR 90.2-97.2] vs. 99.5 mg·h/L [IQR 95.1-104.0], P = 0.07). No significant differences in iohexol-measured kidney function nor meaningful differences in urinary kidney injury biomarkers, kidney injury molecule-1, clusterin, and osteopontin, were detected. Administration of intravenous vancomycin as either a humanized infusion or dose-matched bolus resulted in similar vancomycin exposures. No differences in iohexol-measured GFR nor meaningful differences in urinary kidney injury biomarkers were observed among male Sprague-Dawley rats.

Exploring the Utility of Urinary Creatinine Adjustment for KIM-1, NGAL, and Cystatin C for the Assessment of Kidney Function: Insights from the C-KidnEES Cohort.

Normalization of urinary biomarkers of kidney injury is a common practice in clinical and research settings to account for variations in urine concentration, and urinary creatinine is often used as a reference. However, to date, there is no consensus on the adjustment of urinary biomarkers with creatinine, and both absolute and creatinine-adjusted biomarker levels are adopted for making interpretations of kidney health. Hence, the present study aimed to investigate the associations of urinary creatinine with three widely used kidney injury biomarkers, KIM-1, NGAL, and cystatin C, to validate the applicability of urinary creatinine as a reference for normalization. A cross-sectional study was performed with 2100 students, 10-18 years of age in the Children's Kidney Environmental Exposure Study (C-KidnEES) cohort established in Sri Lanka. As identified in linear regression analyses, normalization of urinary KIM-1, NGAL, and Cys-C to urinary creatinine did not result in significant under-adjustment or over-adjustment to the absolute urinary concentrations, giving no specific rationale for creatinine adjustment. Hence, absolute urinary concentrations of the above biomarkers can be adopted for the characterization of subclinical kidney injury in adolescents in community studies where early morning urine sampling is practiced. However, for spot urine samples, consideration of both absolute and creatinine-adjusted biomarker levels would be a better approach.

Urinary biomarkers of early kidney injury in children with beta-thalassemia

Beta-thalassemia is considered as one of the most common genetic disorders in the world caused by the reduced or absent synthesis of b-globin chain. The aim of this work was to evaluate renal function in children with b-thalassemia using predictive biomarkers such as urinary neutrophil gelatinase-associated lipocalin (NGAL) and N-acetyl-b-D-glycosaminidase (NAG). This prospective case–control study was carried out on 80 subjects aged between 3 and 17 years. The subjects were divided into two equal groups: thalassemia group which included 40 children with b-thalassemia major, and control group which included 40 age- and gender-matched healthy, non-anemic controls without any diseases that could potentially affect renal function, who underwent routine check-ups. All thalassemia patients received chelation therapy: 35 (87.5%) of them were treated with deferasirox and 5 (12.5%) patients received deferasirox + deferoxamine. The results of echocardiography, kidney function tests (serum creatinine, urea and estimated glomerular filtration rate as well as urinary albumin/creatinine ratio and urinary NGAL/urinary albumin–creatinine ratio were insignificantly different between the two groups. Abdominal ultrasound findings were significantly different between both groups. Total WBC counts, platelet counts, the results of liver function tests (total bilirubin, direct bilirubin, alanine transaminase and aspartate aminotransferase), urinary NAG/creatinine ratios, urinary NGAL/creatinine ratios and serum ferritin levels were significantly higher in the thalassemia group, while hemoglobin, urinary NAG/urinary albumin–creatinine ratios were significantly lower in this group. Urinary markers NGAL and NAG could be used as predictive markers of renal disease in b-thalassemia major patients. The study was initiated after obtaining approval from the Ethical Committee of Menoufia University Hospital. Informed written consent was obtained from the parents of the children involved in the study.

Recent ambient temperature and fine particulate matter (PM2.5) exposure is associated with urinary kidney injury biomarkers in children

BackgroundLimited research has examined associations between exposure to ambient temperature, air pollution, and kidney function or injury during the preadolescent period. We examined associations between exposure to ambient temperature and particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) with preadolescent estimated glomerular filtration rate (eGFR) and urinary kidney injury biomarkers. MethodsParticipants included 437 children without cardiovascular or kidney disease enrolled in the Programming Research in Obesity, Growth, Environment and Social Stressors birth cohort study in Mexico City. eGFR and urinary kidney injury biomarkers were assessed at 8–12 years. Validated satellite-based spatio-temporal models were used to estimate mean daily temperature and PM2.5 levels at each participant's residence 7- and 30-days prior to the date of visit. Linear regression and distributed lag nonlinear models (DLNM) were used to examine associations between daily mean temperature and PM2.5 exposure and kidney outcomes, adjusted for covariates. ResultsIn single linear regressions, higher seven-day average PM2.5 was associated with higher urinary alpha-1-microglobulin and eGFR. In DLNM analyses, higher temperature exposure in the seven days prior to date of visit was associated with a decrease in urinary cystatin C of −0.56 ng/mL (95 % confidence interval (CI): −1.08, −0.04) and in osteopontin of −0.08 ng/mL (95 % CI: −0.15, −0.001). PM2.5 exposure over the seven days prior to date of visit was associated with an increase in eGFR of 1.77 mL/min/1.73m2 (95 % CI: 0.55, 2.99) and urinary cystatin C of 0.19 ng/mL (95 % CI: 0.03, 0.35). ConclusionsRecent exposure to ambient temperature and PM2.5 were associated with increased and decreased urinary kidney injury biomarkers that may reflect subclinical glomerular or tubular injury in children. Further research is required to assess environmental exposures and worsening subclinical kidney injury across development.

Flucloxacillin worsens while imipenem-cilastatin protects against vancomycin-induced kidney injury in a translational rat model.

Vancomycin is one of the most common clinical antibiotics, yet acute kidney injury is a major limiting factor. Common combinations of antibiotics with vancomycin have been reported to worsen and improve vancomycin-induced kidney injury. We aimed to study the impact of flucloxacillin and imipenem-cilastatin on kidney injury when combined with vancomycin in our translational rat model. Male Sprague-Dawley rats received allometrically scaled (1) vancomycin, (2) flucloxacillin, (3) vancomycin + flucloxacillin, (4) vancomycin + imipenem-cilastatin or (5) saline for 4 days. Kidney injury was evaluated via drug accumulation and urinary biomarkers including urinary output, kidney injury molecule-1 (KIM-1), clusterin and osteopontin. Relationships between vancomycin accumulation in the kidney and urinary kidney injury biomarkers were explored. Urinary output increased every study day for vancomycin + flucloxacillin, but after the first dose only in the vancomycin group. In the vancomycin + flucloxacillin group, urinary KIM-1 increased on all days compared with vancomycin. In the vancomycin + imipenem-cilastatin group, urinary KIM-1 was decreased on Days 1 and 2 compared with vancomycin. Similar trends were observed for clusterin. More vancomycin accumulated in the kidney with vancomycin + flucloxacillin compared with vancomycin and vancomycin + imipenem-cilastatin. The accumulation of vancomycin in the kidney tissue correlated with increasing urinary KIM-1. Vancomycin + flucloxacillin caused more kidney injury compared with vancomycin alone and vancomycin + imipenem-cilastatin in a translational rat model. The combination of vancomycin + imipenem-cilastatin was nephroprotective.

Body mass index and implications for pediatric kidney health: a cross-sectional study with urinary biomarkers.

Extremes of unhealthy body weight, particularly obesity, are known to increase the risk of chronic kidney diseases. However, the current knowledge of kidney health outcomes associated with unhealthy body weight remains incomprehensive, especially in pediatrics. Therefore, the present study aimed to evaluate body mass index (BMI) and its potential associations with kidney health in a selected subset of school students in Sri Lanka. This cross-sectional study was conducted among students of both sexes in the range of 11-18years of age (N = 1078) in education zones with no reported cases of chronic kidney disease of uncertain etiology. Based on sex- and age-specific BMI percentiles (LMS method), the participants were classified into five BMI groups (severely thin, thin, healthy, overweight, and obese) for measurement of urinary biomarkers of kidney injury: kidney injury molecule (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and albumin creatinine ratio (ACR). The median urinary levels ofNGAL, ACR, and particularly KIM-1, which is a more sensitive indicator of kidney injury, showed no significant differences across the BMI strata. Importantly, moderate correlations of BMI with KIM-1 and NGAL were identified in severely thin girls. According to the present study, these findings do not produce plausibly strong evidence to establish a potential association of BMI with altered kidney function in the studied pediatric communities. Particularly, a likelihood of abnormal kidney health outcomes associated with undernutrition is apparent in severely thin girls. However, in-depth studies are warranted to develop a comprehensive understanding of the associations of nutritional status with pediatric kidney health in Sri Lanka. A higher resolution version of the Graphical abstract is available as Supplementary information.

Urinary Kidney Injury Biomarkers Are Associated with Ischemia-Reperfusion Injury Severity in Kidney Allograft Recipients.

We explored the potential of emerging and conventional urinary kidney injury biomarkers in recipients of living donor (LD) or donation after circulatory death (DCD) kidney transplantation, patients with chronic kidney disease (CKD), and individuals from the general population. Urine samples from kidney allograft recipients with mild (LD; n = 199) or severe (DCD; n = 71) ischemia-reperfusion injury (IRI) were analyzed for neutrophil gelatinase-associated lipocalin (NGAL), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinases 2 (TIMP2), kidney injury molecule-1 (KIM-1), chemokine C-X-C motif (CXCL9), solute carrier family 22 member 2 (SLC22A2), nephrin, and uromodulin (UMOD) by quantitative multiplex LC-MS/MS analysis. The fold-change in biomarker levels was determined in mild and severe IRI and in patients with CKD stage 1-2 (n = 127) or stage ≥3 (n = 132) in comparison to the general population (n = 1438). Relationships between the biomarkers and total protein, β2-microglobulin (B2M), creatinine, and osmolality were assessed. NGAL, IGFBP7, TIMP2, KIM-1, CXCL9, and UMOD were quantifiable, whereas nephrin and SLC22A2 were below the limit of detection. Kidney injury biomarkers were increased up to 6.2-fold in allograft recipients with mild IRI and 8.3-fold in recipients with severe IRI, compared to the reference population, with the strongest response observed for NGAL and B2M. In CKD stage 1-2, B2M, NGAL, IGFBP7, TIMP2, KIM-1, UMOD, and CXCL9 were not altered, but in individuals with CKD stage ≥3, B2M, NGAL, and KIM-1 were increased up to 1.3-fold. IGFBP7, TIMP2, NGAL, and CXCL9 were strongly correlated (all r ≥ 0.8); correlations with B2M and TP were smaller (all r ≤ 0.6). IRI, but not stable CKD, was associated with increased urinary levels of kidney injury biomarkers determined by LC-MS/MS. Absolute and multiplexed protein quantitation by LC-MS/MS is an effective strategy for biomarker panel evaluation for translation toward the clinical laboratory.

Serum and Urinary Biomarkers in COVID-19 Patients with or without Baseline Chronic Kidney Disease

In a prospective, observational, non-interventional, single-center study, we assessed various plasma and urinary biomarkers of kidney injury (neutrophil gelatinase-associated Lipocain [NGAL], kidney-injury molecule-1 [KIM-1], and interleukin-18 [IL-18]); inflammation (IL-6, C-reactive protein [CRP]); plus angiotensin converting enzyme 2 (ACE2) in 120 COVID-19 patients (of whom 70 had chronic kidney disease (CKD) at emergency-department (ED) admission). Our aim was to correlate the biomarkers with the outcomes (death, acute kidney injury [AKI]). All patients had received a chest-CT scan at admission to calculate the severity score (0-5). Biomarkers were also assessed in healthy volunteers and non-COVID-19-CKD patients. These biomarkers statistically differed across subgroups, i.e., they were significantly increased in COVID-19 patients, except for urinary (u)KIM1 and uIL-18. Amongst the biomarkers, only IL-6 was independently associated with mortality, along with AKI and not using remdesivir. Regarding the prediction of AKI, only IL-6 and uKIM1 were significantly elevated in patients presenting with AKI. However, AKI could not be predicted. Having high baseline IL-6 levels was associated with subsequent ventilation requirement and death. The mortality rate was almost 90% when the chest CT-scan severity score was 3 or 4 vs. 6.8% when the severity score was 0-2 (p < 0.0001).

Associations of Prenatal Metals Exposure with Kidney Injury Biomarkers in Children

Background and Aim: Prenatal exposure to toxic metal(loid)s, including arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) during development may have nephrotoxic effects in children. We assessed associations between prenatal metal exposure and urinary kidney injury biomarkers in children. Methods: Analyses included 418 children participating in the PROGRESS birth cohort study in Mexico City. Concentrations of As, Cd, Pb, and Hg (urine only) were quantified in maternal second trimester (2T) blood and urine. Kidney parameters were assessed at 8-10 years of age. We examined associations between individual metals and 1) kidney injury biomarkers using linear regression and 2) a multi-protein kidney index using weighted quantile sum (WQS) regression. Associations of separate urine and blood metal mixtures with individual kidney injury biomarkers were assessed via WQS. Covariates included child’s age, sex, body mass index z-score, urine creatinine, 2T socioeconomic status, and 2T smoking exposure. Results: In single metal analyses, doubling of urine Cd was associated with higher urinary TIMP metallopeptidase inhibitor 1 (TIMP1), alpha-1-microglobulin (A1M), clusterin, and cystatin C. Within the multi-protein index, the association with increased urinary As was predominated by albumin, fatty acid binding protein 1 (FABP1), and interferon gamma-induced protein 10 (IP10), and the association with increased urinary Cd was predominated by albumin, A1M, TIMP1, lipocalin, and FABP1. Decile increases in urine metal mixture was associated with increased urinary albumin, IP10, and cystatin C. Urinary As and Cd comprised 60-96% of the metal mixture weights contributing to the associations. Conclusions: Prenatal urinary metals, individually and as a mixture were associated with increased urinary kidney injury biomarkers in healthy children. Prenatal metals exposure may lead to subclinical glomerular or tubular injury in school age children. Further research is required to ascertain resolution or worsening of subclinical kidney injury at later life stages. Keywords: Heavy metals; Renal health; Mixtures

Reference intervals of urinary kidney injury biomarkers for middle-aged men and women determined by quantitative protein mass spectrometry.

There is an ongoing need to recognize early kidney injury and its progression in structural chronic pathologies. The proteins neutrophil-gelatinase-associated lipocalin (NGAL), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinases 2 (TIMP2), kidney injury molecule-1 (KIM-1), C-X-C motif chemokine 9 (CXCL9), transforming growth factor-beta 1 (TGF-β1), solute carrier family 22 member 2 (SLC22A2), nephrin, cubilin, and uromodulin (UMOD) have been proposed as early kidney injury biomarkers. To guide clinical interpretation, their urinary concentrations should be accompanied by reference intervals, which we here establish in a representative Dutch middle-aged population. The 24 h urine samples from 1443 Caucasian middle-aged men and women were analyzed for the biomarkers by quantitative LC-MS/MS. Biomarker excretion per 24 h were calculated, and urine creatinine and osmolality were measured for dilution normalization. This population was characterized by demographic and anthropometric parameters, comorbid conditions, and conventional kidney function measures. NGAL, IGFBP7, TIMP2, KIM-1, and UMOD could be quantified in this population, whereas nephrin, SLC22A2, and CXCL9 were below their detection limits. Urine creatinine and osmolality were correlated to urine volume (r = -0.71; -0.74) and to IGFBP7 (r = 0.73; 0.71) and TIMP2 (r = 0.71; 0.69). Crude and normalized biomarker concentrations were affected by sex, but not by age, body mass index, smoking, kidney function, or common comorbid conditions. The reference intervals (men; women) were 18-108; 21-131 pmol IGFBP7/mmol creatinine, 1-63; 4-224 pmol NGAL/mmol creatinine, 7-48; 7-59 pmol TIMP2/mmol creatinine, &lt;1-9; &lt;1-12 pmol KIM-1/mmol creatinine, and 0.1-1.2; 0.1-1.7 mg UMOD/mmol creatinine. We present dilution-normalized and sex-stratified urinary reference intervals of kidney injury biomarkers in a middle-aged Caucasian population.

Urinary biomarkers of kidney injury in patients treated with anti-VEGF drugs

Antiangiogenic drugs are widely used in oncological practice and are aimed at inhibiting angiogenesis. Despite the high antitumor efficacy, their use may be limited by nephrotoxicity, and therefore the search for early biomarkers of kidney damage remains relevant, which will preserve a favorable safety profile of therapy. To determine urinary biomarkers of tubular and podocyte damage in patients receiving treatment with antiangiogenic drugs. The study included patients (n=50) who received intravenous anti-VEGF drugs (aflibercept, bevacizumab, ramucirumab) in various chemotherapy regimens. Concentrations of tubular damage markers KIM-1 (Kidney Injury Molecule-1) and NGAL (Neutrophil Gelatinase-Associated Lipocalin), hypoxia marker HIF-1 (Hypoxia-Inducible Factor 1-alpha) in urine samples were determined by enzyme-linked immunosorbent assay (ELISA) before treatment, and during 8 weeks of treatment. To assess the risk factors for kidney damage, a logistic regression analysis was performed with the inclusion of the main clinical and laboratory parameters. A decrease in the calculated GFR of CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration Formula) of less than 60 ml/min per 1.73 m2 at week 8 of treatment was noted in 42% of patients. An increase in NGAL, KIM-1, HIF-1 and nephrin in urine during the first two weeks of therapy predicted the development of renal damage by the 8th week of follow-up. When constructing ROC-curves, the high sensitivity and specificity of these urinary indicators as prognostic markers were established. Among the clinical and laboratory indicators, independent unfavorable prognostic factors of nephrotoxicity were an initial decrease in eGFR, a history of hypertension, an increase in the concentration of KIM-1 and HIF-1 in urine during the first two weeks of therapy. The predictors of renal damage in the treatment with antiangiogenic drugs were previously an increase in NGAL, KIM-1 and HIF-1 in urine during the first two weeks after the start of therapy.

Increase Urinary Biomarkers of Kidney Injury in Patients After Allogenic Hematopoietic Stem Cell Transplant Reflect Kidney Damage Even in Normal Kidney Function

Kidney function in patients undergoing hematopoietic stem cell transplant (HSCT) is frequently worsened by previous chemotherapy and exposure to a variety of nephrotoxic drugs. The aim of the study was to assess biomarkers of kidney injury in patients at least 3 months after HSCT under ambulatory care of the Hematology, Oncology and Internal Medicine Department. We studied 80 prevalent patients after allogeneic HSCT and 32 healthy volunteers to obtain normal ranges for biomarkers. In this cross-sectional study, the following biomarkers of kidney injury in urine were evaluated using commercially available assays: IGFBP7 and TIMP2, netrin-1, and semaphorin A2. All of the biomarkers studied were significantly higher in patients after HSCT compared with the healthy volunteers. When we divided patients according to kidney function (below and over 60 mL/min/1.73m2), we found that only concentration of IGFBP7 was significantly higher in 23 patients with chronic kidney disease (CKD) stage 3 relative to patients with an estimated glomerular filtration rate (eGFR) over 60 mL/min/1.73m2. All biomarkers in both subgroups of patients with eGFRs below and over 60 mL/min/1.73m2 were significantly higher relative to healthy volunteers. In univariate correlations, semaphorin A2 was related to netrin-1 (r=0.47, P < .001), IGFBP7 (r=0.35, P < .01), and TIMP2 (r=0.32, P < .01), whereas IGFBP7 was positively related to serum creatinine (r=0.38, P < .001) and inversely to eGFR (r=-0.36, P < .001). Patients after allogeneic HSCT, despite normal or near normal kidney function, show evidence of kidney injury.