Urinary biomarkers for active Lupus Nephritis that have survived independent validation across cohorts.

Most reported biomarkers for lupus nephritis (LN) have not been independently validated across cohorts. Moreover, many of the documented biomarker candidates have been reported to be elevated in LN compared to healthy controls. However, biomarkers that distinguish patients with active LN (ALN) from inactive systemic lupus erythematosus (iSLE) hold significant clinical utility. Hence, our review attempts to identify urine protein biomarkers for LN that have been independently validated across two or more cohorts and exhibit good diagnostic potential for distinguishing ALN from iSLE. PubMed and OVID were screened for studies assessing the diagnostic value of urinary biomarkers in patients with ALN compared to iSLE. Forty peer-reviewed articles were evaluated, encompassing urine biomarker data from 3,411 distinct patients. Of the 32 candidate biomarkers identified, fourteen were repeatedly reported/tested in four or more papers each, namely ALCAM, CCL2 (MCP1), CD163, HAVCR1 (KIM-1), HPGDS, ICAM-1 (CD54), ICAM-2 (CD102), IGFBP-2, LCN2, NCAM-1 (CD56), SELE (E-Selectin), SELL (L-Selectin), TNFSF12 (TWEAK), and VCAM-1, with most exhibiting C-statistics of 0.80 or more across multiple studies when discriminating patients with ALN from iSLE. The 32 reproducibly elevated biomarkers for active LN mapped to nine functional categories. The urinary proteins reported here promise to serve as a liquid biopsy for ALN. Besides representing potential candidates for diagnostic, monitoring, predictive, and prognostic biomarkers in LN, they also provide a window into potential molecular processes within the kidney that may be driving LN. Thus, ongoing advances in proteomics, which offer wider proteome coverage at increased sensitivity, are likely to further reshape our perspective of urinary biomarkers for LN.

Immune checkpoint inhibitors induce acute interstitial nephritis in mice with increased urinary MCP1 and PD-1 glomerular expression.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) induce acute interstitial nephritis (AIN) in 2-5% of patients, with a clearly higher incidence when they are combined with platinum derivatives. Unfortunately, suitable disease models and non-invasive biomarkers are lacking. To fill this gap in our understanding, we investigated the renal effects of cisplatin and anti-PD-L1 antibodies in mice, assessing PD-1 renal expression and cytokine levels in mice with AIN, and then we compared these findings with those in AIN-diagnosed cancer patients. METHODS: Twenty C57BL6J mice received 200 µg of anti-PD-L1 antibody and 5 mg/kg cisplatin intraperitoneally and were compared with those receiving cisplatin (n = 6), anti-PD-L1 (n = 7), or saline (n = 6). After 7 days, the mice were euthanized. Serum and urinary concentrations of TNFα, CXCL10, IL-6, and MCP-1 were measured by Luminex. The kidney sections were stained to determine PD-1 tissue expression. Thirty-nine cancer patients with AKI were enrolled (AIN n = 33, acute tubular necrosis (ATN) n = 6), urine MCP-1 (uMCP-1) was measured, and kidney sections were stained to assess PD-1 expression. RESULTS: Cisplatin and anti PD-L1 treatment led to 40% AIN development (p = 0.03) in mice, accompanied by elevated serum creatinine and uMCP1. AIN-diagnosed cancer patients also had higher uMCP1 levels than ATN-diagnosed patients, confirming our previous findings. Mice with AIN exhibited interstitial PD-1 staining and stronger glomerular PD-1 expression, especially with combination treatment. Conversely, human AIN patients only showed interstitial PD-1 positivity. CONCLUSIONS: Only mice receiving cisplatin and anti-PDL1 concomitantly developed AIN, accompanied with a more severe kidney injury. AIN induced by this drug combination was linked to elevated uMCP1, consistently with human AIN, suggesting that uMCP1 can be potentially used as an AIN biomarker.

Association Between Urinary Biomarkers and CKD in Extremely Low Gestational Age Neonates.

RATIONALE & OBJECTIVE: Children born before 28 weeks' gestation are at increased risk of chronic kidney disease (CKD). Urine biomarkers may shed light on mechanistic pathways and improve the ability to forecast CKD. We evaluated whether urinary biomarkers in neonates of low gestational age (GA) are associated with a reduced estimated glomerular filtration rate (eGFR) over time. STUDY DESIGN: A cohort study of neonates with an exploratory case-control study of a subset of the cohort. SETTING & PARTICIPANTS: 327 neonates born at 24-27 weeks' gestation with 2-year eGFR data from the PENUT (Preterm Erythropoietin Neuroprotection Trial) and the REPaIReD (Recombinant Erythropoietin for Prevention of Infant Renal Disease) study. EXPOSURES: 11 urinary biomarkers measured at 27, 30, and 34 weeks' postmenstrual age for the primary cohort study and 10 additional biomarkers for the exploratory case-control study. OUTCOMES: eGFR<90mL/min/1.73m2 at 2 years corrected for GA. ANALYTICAL APPROACH: Linear mixed models to assess differences in biomarker values between neonates in whom CKD did and did not develop, accounting for multiple comparisons using Bonferroni-Holm correction in the cohort study only. Cohort analyses were adjusted for sex, GA, and body mass index. Cases were matched to controls on these variables in the case-control study. RESULTS: After adjusting for weeks of GA, urinary levels of α-glutathione-S-transferase (log difference, 0.27; 95% CI, 0.12-0.43), albumin (log difference, 0.13; 95% CI, 0.02-0.25), and cystatin C (log difference, 0.19; 95% CI, 0.04-0.34) were higher in those in whom CKD developed than in those in whom it did not. Urinary albumin and cystatin C levels did not remain significantly different after Bonferroni-Holm correction. In the exploratory case-control analysis, there were no differences in any biomarkers between cases and controls. LIMITATIONS: Early deaths and a high number of subjects without eGFR at 2 years corrected for GA. CONCLUSIONS: Measurement of urinary biomarkers may assist in monitoring neonates who are at risk for CKD. Additional studies are needed to confirm these findings. FUNDING: Grants from government (National Institutes of Health). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01378273. PLAIN-LANGUAGE SUMMARY: Approximately 15 million neonates worldwide are born prematurely, and 2 million are born before 28 weeks' gestation. Many of these children go on to experience chronic kidney disease. Urine biomarkers may allow for early recognition of those at risk for the development of kidney disease. In this study of more than 300 children born before 28 weeks' gestational age, we found higher mean urinary levels of α-glutathione-S-transferase at 27, 30, and 34 weeks in children whose estimated glomerular filtration rate was<90mL/min/1.73m2 at 2 years compared with children whose estimated glomerular filtration rate was>90mL/min/1.73m2 at 2 years. Measurement of urinary biomarkers may assist in monitoring neonates who are at risk for chronic kidney disease. Additional studies are needed to confirm our findings.

Urine biomarkers individually and as a consensus model show high sensitivity and specificity for detecting UTIs.

BACKGROUND: Current diagnoses of urinary tract infection (UTI) by standard urine culture (SUC) has significant limitations in sensitivity, especially for fastidious organisms, and the ability to identify organisms in polymicrobial infections. The significant rate of both SUC "negative" or "mixed flora/contamination" results in UTI cases and the high prevalence of asymptomatic bacteriuria indicate the need for an accurate diagnostic test to help identify true UTI cases. This study aimed to determine if infection-associated urinary biomarkers can differentiate definitive UTI cases from non-UTI controls. METHODS: Midstream clean-catch voided urine samples were collected from asymptomatic volunteers and symptomatic subjects ≥ 60 years old diagnosed with a UTI in a urology specialty setting. Microbial identification and density were assessed using a multiplex PCR/pooled antibiotic susceptibility test (M-PCR/P-AST) and SUC. Three biomarkers [neutrophil gelatinase-associated lipocalin (NGAL), and Interleukins 8 and 1ß (IL-8, and IL-1ß)] were also measured via enzyme-linked immunosorbent assay (ELISA). Definitive UTI cases were defined as symptomatic subjects with a UTI diagnosis and positive microorganism detection by SUC and M-PCR, while definitive non-UTI cases were defined as asymptomatic volunteers. RESULTS: We observed a strong positive correlation (R2 > 0.90; p < 0.0001) between microbial density and the biomarkers NGAL, IL-8, and IL-1ß for symptomatic subjects. Biomarker consensus criteria of two or more positive biomarkers had sensitivity 84.0%, specificity 91.2%, positive predictive value 93.7%, negative predictive value 78.8%, accuracy 86.9%, positive likelihood ratio of 9.58, and negative likelihood ratio of 0.17 in differentiating definitive UTI from non-UTI cases, regardless of non-zero microbial density. NGAL, IL-8, and IL-1ß showed a significant elevation in symptomatic cases with positive microbe identification compared to asymptomatic cases with or without microbe identification. Biomarker consensus exhibited high accuracy in distinguishing UTI from non-UTI cases. CONCLUSION: We demonstrated that positive infection-associated urinary biomarkers NGAL, IL-8, and IL-1ß, in symptomatic subjects with positive SUC and/or M-PCR results was associated with definitive UTI cases. A consensus criterion with ≥ 2 of the biomarkers meeting the positivity thresholds showed a good balance of sensitivity (84.0%), specificity (91.2%), and accuracy (86.9%). Therefore, this biomarker consensus is an excellent supportive diagnostic tool for resolving the presence of active UTI, particularly if SUC and M-PCR results disagree.

From Detection to Cure - Emerging Roles for Urinary Tumor DNA (utDNA) in Bladder Cancer.

PURPOSE OF REVIEW: This review sought to define the emerging roles of urinary tumor DNA (utDNA) for diagnosis, monitoring, and treatment of bladder cancer. Building from early landmark studies the focus is on recent studies, highlighting how utDNA could aid personalized care. RECENT FINDINGS: Recent research underscores the potential for utDNA to be the premiere biomarker in bladder cancer due to the constant interface between urine and tumor. Many studies find utDNA to be more informative than other biomarkers in bladder cancer, especially in early stages of disease. Points of emphasis include superior sensitivity over traditional urine cytology, broad genomic and epigenetic insights, and the potential for non-invasive, real-time analysis of tumor biology. utDNA shows promise for improving all phases of bladder cancer care, paving the way for personalized treatment strategies. Building from current research, future comprehensive clinical trials will validate utDNA's clinical utility, potentially revolutionizing bladder cancer management.

Urinary biomarkers in children with neurogenic and non-neurogenic lower urinary tract dysfunction: A systematic review and meta-analysis.

AIM: The aim of this systematic review is to assess urinary biomarkers studied in children with neurogenic and non-neurogenic lower urinary tract dysfunction (LUTD). MATERIALS AND METHODS: The systematic review was conducted in accordance with the PRISMA guidelines. The screening was performed on PUBMED without any publication date limitation. Only original articles were included. Parameters related to the following topics were obtained: study design, characteristics of participants, number of participants, age, control group, types of biomarkers, measurement technique in urine, subgroup analysis, urodynamic findings, and outcome. Dutch Cochrane Checklist (DCC) and level of evidence by EBRO platform were used for quality assessment. Meta-analysis was performed with the Comprehensive Meta-Analysis Version 4 program. RESULTS: A total of 494 studies were screened and 16 studies were included. 11 (68.75%) were conducted in children with non-neurogenic LUTD and 5 (31.25%) neurogenic LUTD. Nerve growth factor (NGF) was evaluated in 12 studies, brain-derived neurotrophic factor (BDNF) in 5, Tissue Inhibitor of Metalloproteinase-2 (TIMP-2) in 2, transforming growth factor beta-1 (TGF Beta-1) in 2, neutrophil gelatinase-associated lipocalin (NGAL) in 1, and Aquaporin-2 in 1. According to DCC, 10 (62.5%) articles were evaluated on 4 (37.5%) items and 4 articles on 5 items. The average score was 3.91+/-0.56. The level of evidence was found as B for 13 (81.25%) articles and C for 3 (18.75%). In meta-analysis, urinary NGF levels in children with non-neurogenic LUTS were significantly higher than in the healthy control group (Hedges's g = 1.867, standard error = 0.344, variance = 0.119, p = 0.0001). CONCLUSION: Urinary biomarkers are promising for the future with their noninvasive features. However, prospective studies with larger sample sizes are needed to better understand the potential of urinary biomarkers to reflect urodynamic and clinical findings in children with LUTD.

Potential urinary biomarkers in preeclampsia: a narrative review.

INTRODUCTION: Preeclampsia (PE) is a highly relevant pregnancy-related disorder. An early and accurate diagnosis is crucial to prevent major maternal and neonatal complications and mortality. Due to the association of kidney dysfunction with the pathophysiology of the disease, urine samples have the potential to provide biomarkers for PE prediction, being minimally invasive and easy to perform. Therefore, searching for novel biomarkers may improve outcomes. This narrative review aimed to summarize the scientific literature about the traditional and potential urinary biomarkers in PE and to investigate their applicability to screen and diagnose the disorder. METHODS: A non-systematic search was performed in PubMed/MEDLINE, Scopus, and SciELO databases. RESULTS: There is significant divergence in the literature regarding traditionally used serum markers creatinine, cystatin C, and albuminuria, accuracy in PE prediction. As for the potential renal biomarkers investigated, including vascular epithelial growth factor (VEGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase (sFlt-1), urinary levels of PlGF and sFtl-1/PlGF ratio in urine seem to be the most promising as screening tests. The assessment of the global load of misfolded proteins through urinary congophilia, podocyturia, and nephrinuria has also shown potential for screening and diagnosis. Studies regarding the use of proteomics and metabolomics have shown good accuracy, sensitivity, and specificity for predicting the development and severity of PE. CONCLUSION: However, there are still many divergences in the literature, which requires future and more conclusive research to confirm the predictive role of urinary biomarkers in pregnant women with PE.

Urinary biomarkers associated with acute kidney injury in pediatric mechanical circulatory support patients.

BACKGROUND: In patients requiring mechanical circulatory support (MCS), the incidence of acute kidney injury (AKI) is between 37 and 63%. In this study, we performed an exploratory analysis evaluating the relationship of multiple urine biomarkers with AKI development in pediatric MCS patients. METHODS: This is a single center retrospective study in a pediatric cohort receiving MCS from August 2014 to November 2020. We measured 14 urine biomarkers of kidney injury on day 1 following MCS initiation and analyzed their association with development of AKI in the first 7 days of MCS initiation. RESULTS: Sixty patients met inclusion criteria. Patients with AKI were more likely to be supported by venoarterial extracorporeal membrane oxygenation (65% vs. 8.3%, p < 0.001), compared to the no AKI group and less likely to have ventricular assist devices (10% vs. 50%, p < 0.001). There was a significant increase in the median urine albumin and urine osteoactivin in the AKI group, compared to the no AKI group (p = 0.020 and p = 0.018, respectively). When normalized to urine creatinine (UCr), an increased log osteoactivin/UCr was associated with higher odds of AKI development (OR: 2.05; 95% CI: 1.07, 4.44; p = 0.028), and higher log epidermal growth factor (EGF)/UCr (OR: 0.41; 95% CI: 0.15, 0.96) was associated with decreased odds of AKI. CONCLUSIONS: Early increase in urine osteoactivin is associated with AKI development within 7 days of MCS initiation in pediatric patients. Contrary, an increased urine EGF is associated with kidney protection. A higher resolution version of the Graphical abstract is available as Supplementary information.

Immune urinary biomarkers predict infant cardiac surgery-associated acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) occurs frequently after infant cardiac surgery and is associated with poor outcomes, including mortality and prolonged length of stay. AKI mechanisms are poorly understood, limiting therapeutic targets. Emerging data implicates dysregulated immune activation in post-cardiac surgery AKI development. We sought to identify immune-mediated AKI biomarkers after infant cardiopulmonary bypass (CPB)-assisted cardiac surgery. METHODS: A single-center prospective study of 126 infants less than 1 year old undergoing CPB-assisted surgery enrolled between 10/2017 and 6/2019. Urine samples were collected before CPB and at 6, 24, 48, and 72 h after surgery. Immune-mediated biomarkers were measured using commercial ELISA and Luminex™ multiplex kits. Based on subject age, neonatal KDIGO (< 1 month) or KDIGO criteria defined AKI. The Kruskal-Wallis rank test determined the relationship between urinary biomarker measurements and AKI. RESULTS: A total of 35 infants (27%) developed AKI. AKI subjects were younger, underwent more complex surgery, and had longer CPB time. Subjects with AKI vs. those without AKI had higher median urinary chemokine 10 (C-X-C motif) ligand levels at 24, 48, and 72 h, respectively: 14.3 pg/ml vs. 5.3 pg/ml, 3.4 pg/ml vs. 0.8 pg/ml, and 1.15 pg/ml vs. 0.22 pg/ml (p < 0.05) post-CPB. At 6 h post-CPB, median vascular cell adhesion protein 1 (VCAM) levels (pg/mL) were higher among AKI subjects (491 pg/ml vs. 0 pg/ml, p = 0.04). CONCLUSIONS: Urinary CXCL10 and VCAM are promising pro-inflammatory biomarkers for early AKI detection and may indicate eventual AKI therapeutic targets. A higher resolution version of the Graphical abstract is available as Supplementary information.

Kidney Disease and Proteomics: A Recent Overview of a Useful Tool for Improving Early Diagnosis.

Kidney disease is a critical and potentially life-threatening degenerative condition that poses a significant global public health challenge due to its elevated rates of morbidity and mortality. It manifests primarily in two distinct clinical forms: acute kidney injury (AKI) and chronic kidney disease (CKD). The development of these conditions hinges on a multitude of factors, including the etiological agents and the presence of coexisting medical conditions. Despite disparities in their underlying pathogenic mechanisms, both AKI and CKD can progress to end-stage kidney disease (ESKD). This advanced stage is characterized by organ failure and its associated complications, greatly increasing the risk of mortality. There is an urgent need to delve into the pathogenic mechanisms underlying these diseases and to identify novel biomarkers that can facilitate earlier diagnosis. Such early detection is crucial for enhancing the efficacy of therapy and impeding disease progression. In this context, proteomic approaches have emerged as invaluable tools for uncovering potential new markers of different pathological conditions, including kidney diseases. In this chapter, we overview the recent discoveries achieved through diverse proteomic techniques aimed at identifying novel molecules that may play a pivotal role in kidney diseases such as diabetic kidney disease (DKD), IgA nephropathy (IgAN), CKD of unknown origin (CKDu), autosomal dominant polycystic kidney disease (ADPKD), lupus nephritis (LN), hypertensive nephropathy (HN), and COVID-19-associated acute kidney injury (COVID-AKI).

Low daily water intake profile-is it a contributor to disease?

Few previous review articles have focused on the associations between inadequate daily water intake (LOW) or urinary biomarkers of dehydration (UD; low urine volume or high urine osmolality) and multiple diseases. Accordingly, we conducted manual online searches (47 key words) of the PubMed, Embase, and Google Scholar databases with these inclusion criteria: English language, full-text, peer reviewed, no restriction on research design, and three publications minimum. Initially, 3,903 articles were identified based on their titles and abstracts. Evaluations of full length .pdf versions identified 96 studies that were acceptable for inclusion. We concluded that the evidence is insufficient or conflicting for seven disorders or diseases (i.e. suggesting the need for additional clarifying research) and it is lacking for all-cause mortality. Differential characterizations among women and men have been reported in the results of nine studies involving five diseases. Finally, the evidence for associations of LOW or UD is strong for both kidney stones and type 2 diabetes with hyperglycemia. This suggests that great public health value (i.e. reduced disease risk) may result from increased daily water intake-a simple and cost-effective dietary modification.

Role of Urinary Biomarkers (Transforming Growth Factor ß1, Neutrophil Gelatinase-Associated Lipocalin, and Cystatin C) as a Prognostic Factor of Renal Outcome in the Posterior Urethral Valve.

Background: The urinary biomarker response precedes the appearance of any renal structural or functional derangement. Transforming growth factor-ß1 (TGF-ß1), neutrophil gelatinase associated lipocalin (NGAL), and Cystatin C (CysC) can act as the early prognostic markers in posterior urethral valve (PUV) patients. Aim: To compare the urinary levels of TGF-ß1, NGAL, and CysC between PUV cases and age matched controls and to correlate these with renal structural and functional parameters. Materials and Methods: This prospective study included children with PUV diagnosed using the standard investigations and an equal number of age-matched controls with nonurological problems. For the study subjects, the urinary samples were collected at three different time points (pre- and postoperatively at 3 and 6 months), whereas for controls, only single-voided samples were studied. The urinary levels of TGF-ß1, NGAL, and CysC were estimated by the standardized techniques using the ELISA kits. Statistical methods were used to drive the comparisons between cases and controls. Results: Fifteen children with a median age of 10 (5-48) months were enrolled in each of the two groups. The mean uTGF-ß1 in the case group was significantly higher at all three time points (43.20 ± 6.13 pg/ml, 43.33 ± 11.89 pg/ml and 40.71 ± 9.01 pg/ml) as compared to the control group (29.12 ± 8.31 pg/ml) (P ≤ 0.001). The median uNGAL in the case group was also higher (17.78 ng/ml, 2.35 ng/ml and 2.536 ng/ml) as compared to the control group (1.31 ng/ml). However, the difference was significant only preoperatively (P = 0.02). The median uCysC in case group was similarly higher (0.347 µg/ml, 0.439 µg/ml, and 0.382 µg/ml) than the control group (0.243 µg/ml) (P > 0.05). Serum creatinine in the case group (0.49 mg/dl) showed no significant rise above that of control (0.24 mg/dl). A cutoff value of uTGF-ß1 = 36.55 pg/ml (P < 0.001), uNGAL = 0.879 ng/ml (P = 0.02), and uCysC = 0.25 µg/ml (P = 0.22) was found to be associated with renal damage in PUV. A significant correlation was found between uNGAL and S. creatinine at 3 months (r = 0.43, P = 0.017) and 6 months (r = 0.47, P = 0.08). Conclusion: The elevated uTGF-ß1, a decline in uNGAL and an increase in uCysC suggests ongoing inflammation, improvement in hydronephrosis and a prolonged proximal tubular dysfunction in PUV patients, respectively.

Urinary peptides provide information about the risk of mortality across a spectrum of diseases and scenarios.

BACKGROUND: There is evidence of pre-established vulnerability in individuals that increases the risk of their progression to severe disease or death, although the mechanisms causing this are still not fully understood. Previous research has demonstrated that a urinary peptide classifier (COV50) predicts disease progression and death from SARS-CoV-2 at an early stage, indicating that the outcome prediction may be partly due to vulnerabilities that are already present. The aim of this study is to examine the ability of COV50 to predict future non-COVID-19-related mortality, and evaluate whether the pre-established vulnerability can be generic and explained on a molecular level by urinary peptides. METHODS: Urinary proteomic data from 9193 patients (1719 patients sampled at intensive care unit (ICU) admission and 7474 patients with other diseases (non-ICU)) were extracted from the Human Urinary Proteome Database. The previously developed COV50 classifier, a urinary proteomics biomarker panel consisting of 50 peptides, was applied to all datasets. The association of COV50 scoring with mortality was evaluated. RESULTS: In the ICU group, an increase in the COV50 score of one unit resulted in a 20% higher relative risk of death [adjusted HR 1.2 (95% CI 1.17-1.24)]. The same increase in COV50 in non-ICU patients resulted in a higher relative risk of 61% [adjusted HR 1.61 (95% CI 1.47-1.76)], consistent with adjusted meta-analytic HR estimate of 1.55 [95% CI 1.39-1.73]. The most notable and significant changes associated with future fatal events were reductions of specific collagen fragments, most of collagen alpha I (I). CONCLUSION: The COV50 classifier is predictive of death in the absence of SARS-CoV-2 infection, suggesting that it detects pre-existing vulnerability. This prediction is mainly based on collagen fragments, possibly reflecting disturbances in the integrity of the extracellular matrix. These data may serve as a basis for proteomics-guided intervention aiming towards manipulating/ improving collagen turnover, thereby reducing the risk of death.

Cardiovascular risk and renal injury profile in subjects with type 2 diabetes and non-albuminuric diabetic kidney disease.

BACKGROUND: In the last years, the classical pattern of diabetic kidney disease (DKD) has been partially overcome, because of the uncovering of a new DKD phenotype with significant renal dysfunction without presence of albuminuria: the non-albuminuric DKD (NA-DKD). To date, the cardiovascular risk associated with this phenotype is still debated. We investigated the cardiovascular risk and renal injury profile of NA-DKD subjects in comparison with other DKD phenotypes. METHODS: Pulse wave velocity (PWV), intima-media thickness, presence of carotid atherosclerotic plaque, renal resistive index (RRI), and a panel of urinary biomarkers of kidney injury were evaluated in 160 subjects with type 2 diabetes, stratified according to estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (UACR) into four groups: controls (UACR < 30 mg/g and eGFR ≥ 60 mL/min/1.73 m2), A-DKD (Albuminuric-DKD, UACR ≥ 30 mg/g and eGFR ≥ 60 mL/min/1.73 m2), NA-DKD (UACR < 30 mg/g and eGFR < 60 mL/min/1.73 m2), AL-DKD (Albuminuric and Low eGFR-DKD; UACR ≥ 30 mg/g and eGFR < 60 mL/min/1.73 m2). RESULTS: Subjects with NA-DKD showed a higher PWV (11.83 ± 3.74 m/s vs. 10.24 ± 2.67 m/s, P = 0.045), RRI (0.76 ± 0.11 vs. 0.71 ± 0.09, P = 0.04), and prevalence of carotid atherosclerotic plaque (59% vs. 31%, P = 0.009) compared with controls. These characteristics were similar to those of subjects with AL-DKD, whereas the profile of A-DKD subjects was closer to controls. After multiple regression analyses, we found that RRI, that is in turn influenced by eGFR (ß = - 0.01, P = 0.01), was one of the major determinants of PWV (ß = 9.4, P = 0.02). Urinary TreFoil Factor 3, a marker of tubular damage, was higher in NA-DKD subjects vs. controls (1533.14 ± 878.31 ng/mL vs. 1253.84 ± 682.17 ng/mL, P = 0.047). Furthermore, after multiple regression analyses, we found that urinary osteopontin was independently associated with PWV (ß = 2.6, P = 0.049) and RRI (ß = 0.09, P = 0.006). CONCLUSIONS: Our data showed a worse cardiovascular and renal injury profile in NA-DKD subjects. This finding emphasizes the central role of eGFR in the definition of cardiovascular risk profile of diabetic subjects together with albuminuria.

Urine Galectin-3 binding protein reflects nephritis activity in systemic lupus erythematosus.

BACKGROUND: Lupus nephritis (LN) is a major and severe organ involvement in systemic lupus erythematosus (SLE), whose diagnosis and treatment necessitate to perform kidney biopsy, which is an invasive procedure. Non-invasive urine biomarkers are an active area of investigation to support LN diagnosis and management. OBJECTIVE: To investigate the role of urinary galectin-3 binding protein (u-Gal-3BP) as a candidate biomarker of renal disease in biopsy proven LN. PATIENTS AND METHODS: Levels of u-Gal-3BP were investigated in a cross-sectional fashion by ELISA in 270 subjects: 86 LN patients, 63 active SLE patients with no kidney involvement, 73 SLE patients with inactive disease and 48 age and sex-matched population-based controls (PBC). Moreover, urine samples were analysed separately by ELISA for additional markers of kidney pathology: neutrophil gelatinase-associated lipocalin (NGAL), osteopontin (OPN), kidney injury molecule-1 (KIM-1) and galectin-3 (Gal-3). The concentrations of all studied molecules were normalized to urine creatinine levels. In 10 patients, post-treatment levels of the biomarkers were measured. RESULTS: Normalized u-Gal-3BP levels were higher in LN patients compared to the other groups (p < .0001). Comparing different LN classes, u-Gal-3BP levels were higher among patients with proliferative (class III/IV) and membranous (class V) as compared to mesangial (class II) forms (p = .04). In proliferative forms, u-Gal-3BP levels correlated with the activity index in renal biopsies (r = 0.42, p = .004). Moreover, in a subset of 10 patients with repeated kidney biopsy and urine sampling before and after induction treatment, a significant decrease of u-Gal-3BP was observed (p = .03). Among the other markers, KIM-1 was also able to discriminate LN from the other groups, while NGAL, OPN and Gal-3 could not in this cohort. CONCLUSION: Given its ability to discriminate LN patients from active non-renal and inactive SLE patients, the observed correlation with the activity index in renal biopsies, and its levels declining following treatment, u-Gal-3BP shows promise as a non-invasive urinary biomarker to help detecting and to monitor renal involvement in SLE patients and should be validated in larger cohorts.

Association of urinary phytoestrogens with hormone-related cancers and cancer biomarkers: NHANES 1999-2010.

Phytoestrogens may have potential effects on hormone-related cancers (HRC) and cancer biomarkers, but the findings have been inconsistent so far. Participants from the National Health and Nutrition Examination Survey 1999-2010 with information on the levels of urinary phytoestrogens, serum cancer biomarkers and cancer history were included. Sampling-weighted logistic regression models examined the association between urinary phytoestrogens concentrations (creatinine-standardised and log-transformed) and HRC, followed by stratified analyses by race/ethnicity, age and menopausal status for different gender. Correlation analyses between phytoestrogens and cancer biomarkers were performed. Of the total 8844 participants, there were 373 with HRC. We observed total isoflavone and enterodiol excretion were positively associated with HRC, especially in non-Hispanic white female subpopulations (Ptrend < 0·05). Similar association also existed in the total isoflavones and enterodiol levels with breast cancer. Whereas the highest concentration of total isoflavones was significantly linked to a reduced prevalence of HRC (OR = 0·40, 95 % CI: 0·19, 0·84) in white males and of prostate cancer (OR = 0·40, 95 % CI: 0·18, 0·86). Among twenty-four participants with HRC, urinary equol concentration was positively correlated with CA15.3. Also, an inverse correlation of total prostate-specific antigens (PSA) and positive correlation of the PSA ratio with urinary enterolactone were detected in thirteen prostate cancer patients. Our findings indicated that higher concentrations of total isoflavones and enterodiol were positively associated with HRC. Urinary certain phytoestrogen excretion may affect serum cancer biomarker levels in cancer patients. But further prospective studies are needed to provide stronger evidence.

Nontarget Screening of Novel Urinary Biomarkers for Occupational Exposure to Toxic Chemicals from Coking Industry Using HPLC-QTOF-MS.

High-resolution mass spectrometry is an advanced technique for comprehensive screening of toxic chemicals. In this study, urine samples were collected from both an occupationally exposed population at a coking site and normal inhabitants to identify novel urinary biomarkers for occupational exposure to coking contaminants. A coking-site-appropriate analytical method was developed for unknown chemical screening. Through nontarget screening, 515 differential features were identified, and finally, 32 differential compounds were confirmed as candidates for the current study, including 13 polycyclic aromatic hydrocarbon (PAH) metabolites. Besides monohydroxy-PAHs (such as 1-&2-naphthol, 2-&9-hydroxyfluorene, 2-&4-phenanthrol, and 1-&2-hydroxypyrene), many other PAH metabolites including dihydroxy metabolites, PAH oxide, and sulfate conjugate were detected, suggesting that the quantification based solely on monohydroxy-PAHs significantly underestimated the human exposure to PAHs. Furthermore, several novel compounds were recognized that could be considered as biomarkers for the exposure to coking contaminants, including quinolin-2-ol (1.10 ± 0.44 ng/mL), naphthylmethanols (11.4 ± 5.47 ng/mL), N-hydroxy-1-aminonaphthalene (0.78 ± 0.43 ng/mL), hydroxydibenzofurans (17.4 ± 7.85 ng/mL), hydroxyanthraquinone (0.13 ± 0.053 ng/mL), and hydroxybiphenyl (2.70 ± 1.03 ng/mL). Despite their lower levels compared with hydroxy-PAHs (95.1 ± 30.8 ng/mL), their severe toxicities should not be overlooked. The study provides a nontarget screening approach to identify chemicals in human urine, which is crucial for accurately assessing the health risks of toxic chemicals in the coking industry.

CIL-ExPMRM: An Ultrasensitive Chemical Isotope Labeling Assisted Pseudo-MRM Platform to Accelerate Exposomic Suspect Screening.

Exposome is the future of next-generation environmental health to establish the association between environmental exposure and diseases. However, due to low concentrations of exposure chemicals, exposome has been hampered by lacking an effective analytical platform to characterize its composition. In this study, by combining the benefit of chemical isotope labeling and pseudo-multiple reaction monitoring (CIL-pseudo-MRM), we have developed one highly sensitive and high-throughput platform (CIL-ExPMRM) by isotope labeling urinary exposure biomarkers. Dansyl chloride (DnsCl), N-methylphenylethylamine (MPEA), and their isotope-labeled forms were used to derivatize polar hydroxyl and carboxyl compounds, respectively. We have programmed a series of scripts to optimize MRM transition parameters, curate the MRM database (>70,000 compounds), predict accurate retention time (RT), and automize dynamic MRMs. This was followed by an automated MRM peak assignment, peak alignment, and statistical analysis. A computational pipeline was eventually incorporated into a user-friendly website interface, named CIL-ExPMRM (http://www.exposomemrm.com/). The performance of this platform has been validated with a relatively low false positive rate (10.7%) across instrumental platforms. CIL-ExPMRM has systematically overcome key bottlenecks of exposome studies to some extent and outperforms previous methods due to its independence of MS/MS availability, accurate RT prediction, and collision energy optimization, as well as the ultrasensitivity and automated robust intensity-based quantification. Overall, CIL-ExPMRM has great potential to advance the exposomic studies based on urinary biomarkers.

Urinary N-Terminal Pro-Brain Natriuretic Peptide Predicts Acute Kidney Injury and Severe Disease in COVID-19.

INTRODUCTION: The ongoing COVID-19 pandemic is placing an extraordinary burden on our health care system with its limited resources. Accurate triage of patients is necessary to ensure medical care for those most severely affected. In this regard, biomarkers could contribute to risk evaluation. The aim of this prospective observational clinical study was to assess the relationship between urinary N-terminal pro-brain natriuretic peptide (NT-proBNP) and acute kidney injury (AKI) as well as severe disease in patients with COVID-19. METHODS: 125 patients treated with an acute respiratory infection in the emergency department of the University Hospital Regensburg were analyzed. These patients were divided into a COVID-19 cohort (n = 91) and a cohort with infections not caused by severe acute respiratory syndrome-coronavirus-2 (n = 34). NT-proBNP was determined from serum and fresh urine samples collected in the emergency department. Clinical endpoints were the development of AKI and a composite one consisting of AKI, intensive care unit admission, and in-hospital death. RESULTS: 11 (12.1%) COVID-19 patients developed AKI during hospitalization, whereas 15 (16.5%) reached the composite endpoint. Urinary NT-proBNP was significantly elevated in COVID-19 patients who suffered AKI or reached the composite endpoint (each p < 0.005). In a multivariate regression analysis adjusted for age, chronic kidney disease, chronic heart failure, and arterial hypertension, urinary NT-proBNP was identified as independent predictor of AKI (p = 0.017, OR = 3.91 [CI: 1.28-11.97] per standard deviation [SD]), as well as of the composite endpoint (p = 0.026, OR 2.66 [CI: 1.13-6.28] per SD). CONCLUSION: Urinary NT-proBNP might help identify patients at risk for AKI and severe disease progression in COVID-19.

Urinary Biomarkers in a Living Donor Kidney Transplantation Cohort-Predictive Value on Graft Function.

Early non-invasive detection and prediction of graft function after kidney transplantation is essential since interventions might prevent further deterioration. The aim of this study was to analyze the dynamics and predictive value of four urinary biomarkers: kidney injury molecule-1 (KIM-1), heart-type fatty acid binding protein (H-FABP), N-acetyl-ß-D-glucosaminidase (NAG), and neutrophil gelatinase-associated lipocalin (NGAL) in a living donor kidney transplantation (LDKT) cohort. Biomarkers were measured up to 9 days after the transplantation of 57 recipients participating in the VAPOR-1 trial. Dynamics of KIM-1, NAG, NGAL, and H-FABP significantly changed over the course of 9 days after transplantation. KIM-1 at day 1 and NAG at day 2 after transplantation were significant predictors for the estimated glomerular filtration rate (eGFR) at various timepoints after transplantation with a positive estimate (p < 0.05), whereas NGAL and NAG at day 1 after transplantation were negative significant predictors (p < 0.05). Multivariable analysis models for eGFR outcome improved after the addition of these biomarker levels. Several donor, recipient and transplantation factors significantly affected the baseline of urinary biomarkers. In conclusion, urinary biomarkers are of added value for the prediction of graft outcome, but influencing factors such as the timing of measurement and transplantation factors need to be considered.