Analysis Of Urinary Biomarkers Research Articles

A paper-based dual functional biosensor for safe and user-friendly point-of-care urine analysis.

Safe, accurate, and reliable analysis of urinary biomarkers is clinically important for early detection and monitoring of the progression of chronic kidney disease (CKD), as it has become one of the world's most prevalent non-communicable diseases. However, current technologies for measuring urinary biomarkers are either time-consuming and limited to well-equipped hospitals or lack the necessary sensitivity for quantitative analysis and post a health risk to frontline practitioners. Here we report a robust paper-based dual functional biosensor, which is integrated with the clinical urine sampling vial, for the simultaneous and quantitative analysis of pH and glucose in urine. The pH sensor was fabricated by electrochemically depositing IrOx onto a paper substrate using optimised parameters, which enabled an ultrahigh sensitivity of 71.58 mV pH-1. Glucose oxidase (GOx) was used in combination with an electrochemically deposited Prussian blue layer for the detection of glucose, and its performance was enhanced by gold nanoparticles (AuNPs), chitosan, and graphite composites, achieving a sensitivity of 1.5 μA mM-1. This dual function biosensor was validated using clinical urine samples, where a correlation coefficient of 0.96 for pH and 0.98 for glucose detection was achieved with commercial methods as references. More importantly, the urine sampling vial was kept sealed throughout the sample-to-result process, which minimised the health risk to frontline practitioners and simplified the diagnostic procedures. This diagnostic platform, therefore, holds high promise as a rapid, accurate, safe, and user-friendly point-of-care (POC) technology for the analysis of urinary biomarkers in frontline clinical settings.

Factors influencing occupational exposure to pyrethroids and glyphosate: An analysis of urinary biomarkers in Malaysia, Uganda and the United Kingdom

BackgroundLong-term exposure to pesticides is often assessed using semi-quantitative models. To improve these models, a better understanding of how occupational factors determine exposure (e.g., as estimated by biomonitoring) would be valuable. MethodsUrine samples were collected from pesticide applicators in Malaysia, Uganda, and the UK during mixing/application days (and also during non-application days in Uganda). Samples were collected pre- and post-activity on the same day and analysed for biomarkers of active ingredients (AIs), including synthetic pyrethroids (via the metabolite 3-phenoxybenzoic acid [3-PBA]) and glyphosate, as well as creatinine. We performed multilevel Tobit regression models for each study to assess the relationship between exposure modifying factors (e.g., mixing/application of AI, duration of activity, personal protective equipment [PPE]) and urinary biomarkers of exposure. ResultsFrom the Malaysia, Uganda, and UK studies, 81, 84, and 106 study participants provided 162, 384 and 212 urine samples, respectively. Pyrethroid use on the sampling day was most common in Malaysia (n = 38; 47%), and glyphosate use was most prevalent in the UK (n = 93; 88%). Median pre- and post-activity 3-PBA concentrations were similar, with higher median concentrations post-compared to pre-activity for glyphosate samples in the UK (1.7 to 0.5 μg/L) and Uganda (7.6 to 0.8 μg/L) (glyphosate was not used in the Malaysia study). There was evidence from individual studies that higher urinary biomarker concentrations were associated with mixing/application of the AI on the day of urine sampling, longer duration of mixing/application, lower PPE protection, and less education/literacy, but no factor was consistently associated with exposure across biomarkers in the three studies. ConclusionsOur results suggest a need for AI-specific interpretation of exposure modifying factors as the relevance of exposure routes, levels of detection, and farming systems/practices may be very context and AI-specific.

Renal injury, biomarkers, and myositis, an understudied aspect of disease: prospective study in the MyoCite cohort.

The mechanisms leading to chronic kidney disease (CKD) in patients with idiopathic inflammatory myopathies (IIMs) are poorly understood. We assessed the prevalence of subclinical renal injury in patients with IIMs, through elevation in biomarker levels of tubular injury and fibrosis (NGAL, KIM1, Activin A, CD163, and Cys-c), and assessed differences between subtypes of IIMs, and the effect of disease activity and duration. Clinical data, core set measures, sera and urine were prospectively collected from all patients enrolled in the MyoCite cohort from 2017 to 2021. Twenty healthy subjects (HC) and 16 patients with acute kidney injury (AKI) were included as controls. Baseline and follow up data for IIMs were included. Enzyme-linked immunosorbent assay (ELISA) was used to measure urine NGAL (Human Lipocalin-2/NGAL Duoset ELISA, Cat no: DY1757), KIM1 (Human TIM-1/KIM 1/HAVCR Duoset ELISA, Cat.no: DY1750B), Activin A (Human Activin A Duoset ELISA, Cat no: DY338), CD163 (Human CD163 Duoset ELISA,Cat no: DY1607-05), and Cys-c (Human Cystatin C Duoset ELISA, Cat. no.: DY1196) levels, while eGFR (unit mL/min/1.73 m2) was calculated by the Cockcroft-Gault formula and CKD-EPI formula. Analysis of 201 visits of 110 adult patients with IIMs indicated higher normalized biomarker levels compared to HCs, and comparable to patients with AKI, with the exception of NGAL, which was higher in the AKI group. Notably 72 (49%) patients with IIMs had eGFR<90; the levels of the 5 biomarkers were comparable between active and inactive IIMs, and different subtypes of IIMs. Similarly, a poor correlation between urine biomarker levels and core set measures of activity and damage was found. Changes in biomarker levels on follow-up did not correlate with eGFR changes. This exploratory analysis of urinary biomarkers identified low eGFR and elevated biomarkers of CKD in nearly half of the patients with IIMs, comparable to patients with AKI and higher than HCs, indicative of potential renal damage in IIMs that may have a lead to complications in other systems.

Antihypertensive Effect of Long-Term Monotherapy with Esaxerenone in Patients with Essential Hypertension: Relationship Between Baseline Urinary Sodium Excretion and Its Antihypertensive Effect.

IntroductionThe blood pressure (BP) control mechanism for mineralocorticoid receptor blockers is unclear, and analysis of their use as a single agent in the clinical setting is required to resolve this uncertainty. There is a paucity of data on esaxerenone monotherapy assessing its long-term antihypertensive effect and urinary biomarkers.MethodsThis post hoc exploratory substudy of a long-term phase 3 study evaluated the effect of esaxerenone monotherapy (2.5 or 5 mg/day) in treatment-naïve patients who continued the therapy during the 52-week study period (n = 25). In addition to blood biomarkers, urinary biomarkers were also assessed in 24-h urine collection samples.ResultsEsaxerenone monotherapy was associated with consistent reductions in systolic/diastolic BP in the substudy population (− 23.5/− 13.1 mmHg at week 52, p < 0.001 vs baseline). Plasma aldosterone concentrations and plasma renin activity significantly increased during esaxerenone monotherapy at all time points. On the basis of the observations that both urine volume and urinary sodium excretion also decreased up to the end of the study, and were significantly lower at 12 weeks, patients were further categorized into higher/lower urinary sodium excretion subgroups according to whether their baseline values were above or below the median. In the group with higher baseline urinary sodium excretion, esaxerenone exhibited a significantly greater decrease in systolic/diastolic BP compared to the lower baseline group.ConclusionEsaxerenone exhibited sustained and stable antihypertensive activity even when administered as a single agent for 52 weeks in patients with essential hypertension. The additional urinary biomarker analysis suggests that the BP-lowering effects of esaxerenone may be partly exerted via mechanisms related to salt and water retention, and that the effect is particularly pronounced in patients with hypertension and higher baseline urinary sodium excretion, which may reflect a state of excessive salt intake.Trial registrationNCT02722265.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12325-022-02282-3.

Filling gaps between exposure modeling and the analysis of urinary biomarkers using personal air monitoring: An intervention study of permethrin used in home insecticide spray.

Permethrin is one of the most widely used active ingredients in spray-type home insecticides. However, indoor permethrin exposure resulting from the use of home insecticides is not well-characterized, as measured permethrin concentrations in indoor environmental and biological media with a known application rate are scarce. We conducted an intervention study with four participants for seven days. We conducted personal air monitoring and collected 24-h urine samples in which we quantified time-weighted average (TWA) permethrin concentrations in indoor air (Cair ) and urinary concentrations of two permethrin metabolites, 3-phenoxybenzoic acid (3-PBA) and cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis/trans-DCCA). We also estimated (1) TWA Cair using a simple indoor air model and (2) urinary excreted (UE) mass using a simple excretion model with both estimated and measured TWA Cair . Measurements of TWA Cair from personal air monitoring were lower than those estimated from the indoor model by a factor of 2.9 to 49.4. The ratio of estimated to measured UE mass ranged 3.5-18.2 when using estimated TWA Cair and 1.1-2.9 when using measured TWA Cair . Smaller ratios in estimating internal permethrin exposure from personal air monitoring suggest that personal air monitoring could reduce uncertainties in permethrin exposure assessment resulting from the use of spray-type insecticides.

Proteome analysis of urinary biomarkers in a cigarette smoke-induced COPD rat model

BackgroundChronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease caused by inhalation of cigarette smoke (CS) and other harmful gases and particles.MethodsThis study aimed to explore potential urinary biomarkers for CS-induced COPD based on LC–MS/MS analysis.ResultsA total of 340 urinary proteins were identified, of which 79 were significantly changed (30, 31, and 37 at week 2, 4 and 8, respectively). GO annotation of the differential urinary proteins revealed that acute-phase response, response to organic cyclic compounds, complement activation classical pathway, and response to lead ion were significantly enriched at week 2 and 4. Another four processes were only enriched at week 8, namely response to oxidative stress, positive regulation of cell proliferation, thyroid hormone generation, and positive regulation of apoptotic process. The PPI network indicated that these differential proteins were biologically connected in CS-exposed rats. Of the 79 differential proteins in CS-exposed rats, 56 had human orthologs. Seven proteins that had changed at week 2 and 4 when there were no changes of pulmonary function and pathological morphology were verified as potential biomarkers for early screening of CS-induced COPD by proteomic analysis. Another six proteins that changed at week 8 when obvious airflow obstruction was detected were verified as potential biomarkers for prognostic assessment of CS-induced COPD.ConclusionsThese results reveal that the urinary proteome could sensitively reflect pathological changes in CS-exposed rats, and provide valuable clues for exploring COPD biomarkers.

Proteome Analysis of Urinary Biomarkers in a Bovine IRBP-Induced Uveitis Rat Model via Data-Independent Acquisition and Parallel Reaction Monitoring Proteomics.

Uveitis, a group of intraocular inflammatory diseases, is one of the major causes of severe visual impairment among the working-age population. This study aimed to screen potential urinary biomarkers for uveitis based on proteome analysis. An experimental autoimmune uveitis (EAU) rat model induced by bovine interphotoreceptor retinoid-binding protein (IRBP) was used to mimic uveitis. In discovery phase, a total of 704 urinary proteins were identified via data-independent acquisition (DIA) proteomic technique, of which 76 were significantly changed (34, 36, and 37 on days 5, 8, and 12, respectively, after bovine IRBP immunization). Gene Ontology annotation of the differential proteins indicates that acute-phase response, innate immune response, neutrophil aggregation, and chronic inflammatory response were significantly enriched. Protein-protein interaction network indicates that these differential urinary proteins were biologically connected in EAU, as a group. In validation phase, 17 proteins having human orthologs were verified as the potential markers associated with uveitis by parallel reaction monitoring (PRM) targeted quantitative analysis. Twelve differential proteins changed even when there were no clinical manifestations or histopathological ocular damage. These 12 proteins are potential biomarkers for early diagnosis of uveitis to prevent the development of visual impairment. Five differential proteins changed at three time-points and showed progressive changes as the uveitis progressed, and another five differential proteins changed only on day 12 when EAU severity peaked. These 10 proteins may serve as potential biomarkers for prognostic evaluation of uveitis. Our findings revealed that the urinary proteome could sensitively reflect dynamic pathophysiological changes in EAU, and represent the first step towards the application of urinary protein biomarkers for uveitis.

Assessment of Dietary Exposure to Ochratoxin A in Lebanese Students and Its Urinary Biomarker Analysis.

The present study investigated the dietary and urinary OTA occurrence among 44 Lebanese children. Relying on HPLC-FLD analysis, OTA was found in all the urine samples and in 46.5% and 25% of the 24 h duplicate diet and dinner samples, respectively. The means of OTA levels in positive samples were 0.32 ± 0.1 ng/g in 24 h diet, 0.32 ± 0.18 ng/g in dinner and 0.022 ± 0.012 ng/mL in urines. These values corresponded to margin of exposure (MOE) means of 7907 ± 5922 (neoplastic) and 2579 ± 1932 (non-neoplastic) calculated from positive 24 h diet, while 961 ± 599 (neoplastic) and 313 ± 195 (non-neoplastic) calculated from the urine. Since the MOE levels for the neoplastic effect were below the limit (10,000), a major health threat was detected and must be addressed as a health institutions’ priority. Besides, the wide difference between PDIs and MOEs calculated from food and urine suggests conducting further OTA’s toxicokinetics studies before using urine to measure OTA exposure.

Exposure to fire smoke in fire training structures: A prospective observational study

The aim of this study was to assess the level of exposure to and contamination by smoke within a population of firefighter instructors. We performed a prospective observational study from September 17 to September 26, 2018, using environmental samples and urinary biomarker analysis. Occupational exposure limits (OELs) were never exceeded, except for carbon monoxide for the fire attack training chamber and formaldehyde and carbon monoxide for the fire box. As regards to urinary biomarkers, we observed that 1OHP and 1-naphtol did accumulate. The pre-post analysis showed an acute exposure exceeding the BRVs of benzene, 1-hydroxypyrene and naphtol, except for 3-benzo[a]pyrene which was undetectable in half of the cases. Even if values were reassuring, an effort could be made to improve the working conditions and reduce contamination by rethinking the respiratory protection and improving PPE quality.

Proteome Analysis of Urinary Biomarkers in Acute Hypercoagulable State Rat Model.

Thrombotic diseases are usually preceded by a hypercoagulable state in the body. This study aimed to screen potential urinary biomarkers for hypercoagulable state based on proteome analysis. Wistar rats were administered with the hemostatic agent etamsylate to establish hypercoagulable state. Urine samples were collected for proteome analysis. We found 20 proteins with levels more than 1.5-fold in difference between control rats and model rats. We searched human homologs of 20 rat proteins and identified 13 human proteins. Of the 13 human homologous proteins, nine were members of human core urinary proteome. Human homologous proteins of differential proteins were highly expressed in 31 human tissues, especially in the kidneys followed by digestive system and reproductive system. Surprisingly, we did not identify known coagulation factors as differential proteins in the urine of model rats. Hypercoagulable state of the body may not involve direct changes in coagulation factors but causes the changes upstream of the coagulation cascade system. Common differential urinary proteins between different hypercoagulable states suggest some common pathways in the formation of hypercoagulable states and may serve as potential biomarkers for the prevention and treatment of thrombotic diseases.

Mass-Spectrometry Analysis of Urinary Biomarkers of Endothelial Injury in Sickle Cell Anemia Patients

BACKGROUND : Sickle cell anemia (SCA) patients are predisposed to the development of chronic kidney disease (CKD). Vascular dysfunction plays an important role in the etiology of CKD and is a major complication in SCA. Biomarkers of endothelial dysfunction VCAM and Activin A were recently described for diagnostics of CKD in Diabetic Kidney Disease and Systemic Lupus Erythematosus. Previously, we identified several urinary biomarkers of CKD in SCA patients using mass-spectrometry analysis. These biomarkers reflect the pathophysiology of SCA, including markers of iron homeostasis (ceruloplasmin (CP), transferrin (TrF), hemoglobin (Hgb), ferritin (FrT)); inflammation (orosomucoid (ORM)); and glomerular hyperfiltration (HGFL). However, the urinary biomarkers of endothelial injury in SCA patients are unknown. HYPOTHESIS: We hypothesized that urinary biomarkers of endothelial injury can be identified by mass-spectrometry and that they correlate with hemoglobinuria and hyperfiltration. METHODS: We tested mass-spectrometry data obtained from spot urine samples of 19 SCA patients without CKD in a steady state from the University of Illinois at Chicago. Samples were run in triplicates (total 57 spectra) and mass spectrometry analysis was carried out using Proteome Discoverer 2.2 (Thermo Fisher Scientific) and Ingenuity Pathway Analysis (IPA, Qiagen) software. Protein abundances were calculated using Proteome Discoverer 2.2 and correlated with hyperfiltration and hemoglobinuria. RESULTS: We re-analyzed previously obtained mass-spectra using the recently released Proteome Discoverer 2.2 program and identified 819 proteins that were further analyzed with IPA software. Proteins were sorted into the categories associated with renal necrosis (31 proteins), glomerular injury (16 proteins), and renal hypoplasia (9 proteins) using IPA. Because of a lack of vascular injury pathways in IPA, nine proteins associated with endothelial or vascular injury were manually picked including VCAM and Activin A (Table 1). Abundances were calculated for each of the nine selected proteins related to endothelial injury in 57 samples and normalized to the urinary creatinine. Results were stratified for hemoglobinuria and hyperfiltration. Four proteins showed 2-4 fold higher abundances in the samples with hemoglobinuria (BMPER, NRG3, MKI67, and TJP2), but the increase was statistically significant for NRG3 and MKI67 only. In the samples from patients with hyperfiltration, BAMBI and NOS2 abundances were increased over 2-fold but the abundance of NRG3 was decreased. Ingenuity network analysis showed changes in immunoglobulin production for MKI67 network; ERK1/2 signaling for NRG3 pathway; cell cycle and NF-kB signaling for BAMBI and cell cycle proteins and RNA polymerase II transcription for NOS2 network. CONCLUSIONS: Markers of endothelial injury are found in the urinary proteome in correlation with hemoglobinuria and hyperfiltration. Further analysis to validate these biomarkers and correlate them with CKD progression is needed. LIMITATION: Research participants were from a small cohort of patients from one center. ACKNOWLEDGMENTS: This work was supported by NIH Research Grants (1P50HL118006, 1R01HL125005, 5G12MD007597 and 1SC1HL150685). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Disclosures Saraf: Novartis, Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Boards, Speakers Bureau; Pfizer, Global Blood Therapeutics, Novartis: Research Funding. Gordeuk:Imara: Research Funding; Ironwood: Research Funding; Novartis: Consultancy; CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding.

Torsemide Is Associated with Higher Levels of Urinary Biomarkers of Tubular Injury Compared to Furosemide

Introduction In patients with heart failure (HF), loop diuretics including torsemide and furosemide are a cornerstone of therapy for volume overload. Torsemide may be associated with enhanced natriuresis which could hemodynamically lead to worsening renal function (WRF). If renal hypoperfusion is persistent and severe, renal tubular injury (RTI) may occur but WRF does not always correlate with renal tubular injury. Urinary biomarker analysis can help identify when renal tubular injury occurs. Hypothesis In patients with chronic HF, use of torsemide is associated with higher biomarker levels of urinary RTI compared to furosemide. Methods Urine samples were collected from patients with chronic HF who had been treated for at least one month with furosemide (n=15) or torsemide (n=10). Urinary concentrations of the following biomarkers were compared between groups: albumin, β-2 microglobulin (β2M), CystatinC, epidermal growth factor (EGF), neutrophil gelatinase-associated lipocalin (NGAL), osteopontin (OPN), and uromodulin. Results One patient in the furosemide group had outliers in several biomarkers and was excluded from the analysis. All urinary markers were present in higher concentration in the torsemide group. Using a nonparametric Wilcoxon test, statistically significant differences were found in the distribution of urinary albumin (p=0.001), β-2M (p=0.03), and NGAL (p=.04) between the two groups. Conclusion Significantly higher levels of RTI biomarkers in the torsemide group suggest that there may be a greater degree of WRF with torsemide compared with furosemide. More significant differences between other urinary biomarkers may be seen with a greater sample size. This study was limited by sample size and inability to compare concentration of urine. Further study is warranted to explore the difference in these groups.

Mass Spectrometry-Based Analysis of Urinary Biomarkers for Dietary Tomato Intake.

In this study, the applicability of several β-carboline, imidazole, and steroidal alkaloids as biomarkers for tomato juice intake is evaluated. Over the course of a 2-week crossover dietary intervention study, 14 volunteers were given low and high doses of tomato juice after 3 days of avoiding tomato-based products. On the day of consumption and the following days, volunteers provided urine samples that were quantitatively analyzed by high-performance liquid chromatography-tandem mass spectrometry. Herein, glucose-derived β-carboline alkaloids are determined as supporting, yet non-specific dietary biomarkers for tomato juice intake. Several imidazole alkaloids represent further biomarkers, which are shown to specifically indicate consumption of tomato juice for 24 h and partly >24 h. Additionally, steroidal alkaloids derived from esculeogenin B are determined to be specific biomarkers for tomato juice detectable for at least 48 h after consumption. The intake of low and high amounts of tomato juice is significantly distinguishable based on the urinary excretion of all determined biomarkers as well. The dietary intake of tomato juice is conclusively traceable based on urinary excretion of multiple β-carboline, imidazole, and steroidal alkaloids, and can be determined for up to 48 h after consumption. Furthermore, different intake doses can clearly be distinguished based on their urinary excretion.

Evaluation of statistical techniques to normalize mass spectrometry-based urinary metabolomics data

Human urine recently became a popular medium for metabolomics biomarker discovery because its collection is non-invasive. Sometimes renal dilution of urine can be problematic in this type of urinary biomarker analysis. Currently, various normalization techniques such as creatinine ratio, osmolality, specific gravity, dry mass, urine volume, and area under the curve are used to account for the renal dilution. However, these normalization techniques have their own drawbacks. In this project, mass spectrometry-based urinary metabolomic data obtained from prostate cancer (n = 56), bladder cancer (n = 57) and control (n = 69) groups were analyzed using statistical normalization techniques. The normalization techniques investigated in this study are Creatinine Ratio, Log Value, Linear Baseline, Cyclic Loess, Quantile, Probabilistic Quotient, Auto Scaling, Pareto Scaling, and Variance Stabilizing Normalization. The appropriate summary statistics for comparison of normalization techniques were created using variances, coefficients of variation, and boxplots. For each normalization technique, a principal component analysis was performed to identify clusters based on cancer type. In addition, hypothesis tests were conducted to determine if the normalized biomarkers could be used to differentiate between the cancer types. The results indicate that the determination of statistical significance can be dependent upon which normalization method is utilized. Therefore, careful consideration should go into choosing an appropriate normalization technique as no method had universally superior performance.

Analysis of Urinary Biomarkers for Early-Life Exposure to Organophosphate Pesticides and Pyrethroids

Analysis of Urinary Biomarkers for Early-Life Exposure to Organophosphate Pesticides and Pyrethroids

Presence of the Carcinogen N'-Nitrosonornicotine in Saliva of E-cigarette Users.

Many harmful constituents are present in e-cigarettes at much lower levels than in cigarette smoke, and the results of analysis of urinary biomarkers in e-cigarette users are consistent with these findings. However, understanding the health effects of chronic exposures to e-cigarette aerosols may require thinking beyond these comparisons. In this study, we investigated the endogenous formation of the tobacco-specific oral and esophageal carcinogen N'-nitrosonornicotine (NNN) in e-cigarette users. Salivary NNN, nornicotine, and nicotine as well as urinary tobacco biomarkers, including total NNN, were analyzed in 20 e-cigarette users, 20 smokers, and 19 nonsmokers. Nornicotine and NNN levels in e-cigarettes used by the study participants were also analyzed. The mean of NNN in saliva of e-cigarette users was 14.6 (±23.1) pg/mL, ranging from nonquantifiable (below the limit of quantitation, LOQ) to 76.0 pg/mL. In smokers, salivary NNN ranged from below LOQ to 739pg/mL, with 80% of smokers having salivary NNN in the range of levels found in e-cigarette users. Consistent with a previous report, very low levels of urinary total NNN were present in only 5 out of 20 e-cigarette users (ranging from 0.001 to 0.01 pmol/mL urine). Only trace levels of NNN were found in e-cigarette liquids. Together, our findings demonstrate that NNN is formed endogenously in e-cigarette users. While the overall exposure to NNN in e-cigarette users is dramatically lower than in smokers, the known carcinogenic potency of NNN warrants further investigations into the potential consequences of its endogenous formation. Salivary NNN, rather than urinary total NNN, which accounts for only 1-3% of the NNN dose, should be used to monitor e-cigarette users' exposure to this carcinogen.

Prediction of contrast-induced acute kidney injury by early post-procedural analysis of urinary biomarkers and intra-renal Doppler flow indices in patients undergoing coronary angiography.

The study was designed to evaluate the applicability of combined assessment of urinary biomarkers and intra-renal Doppler flow indices for the prediction of contrast-induced acute kidney injury (CI-AKI) after coronary angiography/percutaneous coronary interventions (CA/PCI). This prospective observational study covered 95 consecutive patients with coronary artery disease subject to elective or urgent CA/PCI. Doppler intra-renal flow indices were assessed before and 1 h following CA/PCI. Urine samples were collected within 24 h before and 6 h after CA/PCI and assayed for urinary interleukin-18 (IL-18), liver-fatty acid-binding protein (L-FABP), and kidney injury molecule-1 (KIM-1) using ELISA method. CI-AKI was defined as ≥50% relative or ≥0.3 mg/dL absolute increase of serum creatinine concentration at 48 h post-procedurally. CI-AKI was confirmed in nine patients (9.5%). CI-AKI onset was associated with significantly higher urinary KIM-1 at 6 h (P = 0.003) and ΔKIM-1 concentrations (P = 0.001), and urinary IL-18 at 6 h (P = 0.014) and ΔIL-18 concentrations (P = 0.012), however, L-FABP and ΔL-FABP levels were comparable in both groups. Receiver operating characteristic curve analysis denoted that post-procedural IL-18 levels at 6 h >89.8 pg/mg (AUC = 0.75, P = 0.007), KIM-1 at 6 h >0.425 ng/mg (AUC = 0.81, P = 0.001), renal resistive index (RRI) at 1 h >0.73 (AUC 0.88; P < 0.0001), and renal pulsatility index (RPI) at 1 h >0.86 (AUC = 0.86; P < 0.0001) predicted CI-AKI onset. Logistic regression analysis of postoperative predictors revealed that IL-18 and RRI were independent predictors of CI-AKI onset (AUC = 0.96; P < 0.0001). Joint assessment of early post-procedural urinary biomarkers and Doppler renovascular parameters aids early diagnosis of CI-AKI in patients undergoing coronary interventions.

Evidence of ochratoxin A conjugates in urine samples from infants and adults

Ochratoxin A (OTA), a mycotoxin with nephrotoxic and carcinogenic properties, is an important contaminant of food and feed. Analysis of OTA in human biological fluids (blood, urine, or breast milk) has documented frequent exposure to this mycotoxin, yet at quite variable levels in different population groups across the world. Urine is the preferred matrix in biomonitoring since sample collection is non-invasive and better accepted by study participants. As only a small fraction of the ingested OTA is excreted in urine, determination of urinary OTA requires sensitive analytical techniques, and phase-II-metabolites should be also considered as biomarkers of exposure. Yet, data published so far on the presence of OTA-glucuronide/sulfate in human urine have been contradictory. In this study, urines (n = 38) from two groups of breastfed infants (German and Turkish) and from German adults were now analysed for the presence of OTA glucuronides or sulfates by an indirect method, i.e. by comparing the levels of OTA (aglycone) in urines without and after enzymatic hydrolysis with ß-glucuronidase/arylsulfatase. Additionally, ochratoxin A-8-β-glucuronide and open lactone ochratoxin A-8-β-glucuronide were synthesized to serve as reference materials for metabolite analysis. Attempts for definitive confirmation of glucuronides of OTA via direct identification in LC-MS/MS analysis were hampered by the lower ionizability of the conjugates compared to the parent compound. Considerable increases in OTA levels were found after enzymatic hydrolysis in several (not all) urine samples and provide clear evidence for the excretion of OTA-conjugates. The latter observation is of importance, since OTA phase-II-metabolites may escape detection when direct methods are applied for urinary biomarker analysis. In conclusion, enzymatic hydrolysis of urine samples is highly advisable in order to avoid an underestimation of the OTA-exposure.

TCT-383 Analysis of urinary biomarkers of contrast-induced acute kidney injury following coronary angiography

TCT-383 Analysis of urinary biomarkers of contrast-induced acute kidney injury following coronary angiography

Urinary Biomarkers KIM-1 and NGAL for Detection of Chronic Kidney Disease of Uncertain Etiology (CKDu) among Agricultural Communities in Sri Lanka.

Chronic Kidney Disease of uncertain etiology (CKDu) is an emerging epidemic among farming communities in rural Sri Lanka. Victims do not exhibit common causative factors, however, histopathological studies revealed that CKDu is a tubulointerstitial disease. Urine albumin or albumin-creatinine ratio is still being used as a traditional diagnostic tool to identify CKDu, but accuracy and prevalence data generated are questionable. Urinary biomarkers have been used in similar nephropathy and are widely recognised for their sensitivity, specificity and accuracy in determining CKDu and early renal injury. However, these biomarkers have never been used in diagnosing CKDu in Sri Lanka. Male farmers (n = 1734) were recruited from 4 regions in Sri Lanka i.e. Matara and Nuwara Eliya (farming locations with no CKDu prevalence) and two CKDu emerging locations from Hambantota District in Southern Sri Lanka; Angunakolapelessa (EL1) and Bandagiriya (EL2). Albuminuria (ACR ≥ 30mg/g); serum creatinine based estimation of glomerular filtration rate (eGFR); creatinine normalized urinary kidney injury molecule (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were measured. Fourteen new CKDu cases (18%) from EL1 and nine CKDu cases (9%) from EL2 were recognized for the first time from EL1, EL2 locations, which were previously considered as non-endemic of the disease and associated with persistent albuminuria (ACR ≥ 30mg/g Cr). No CKDu cases were identified in non-endemic study locations in Matara (CM) and Nuwara Eliya (CN). Analysis of urinary biomarkers showed urinary KIM-1 and NGAL were significantly higher in new CKDu cases in EL1 and EL2. However, we also reported significantly higher KIM-1 and NGAL in apparently healthy farmers in EL 1 and EL 2 with comparison to both control groups. These observations may indicate possible early renal damage in absence of persistent albuminuria and potential capabilities of urinary KIM-1 and NGAL in early detection of renal injury among farming communities in Southern Sri Lanka.