Upconversion Nanoparticle-Based Dot-Blot Immunoassay for Quantitative Biomarker Detection.

Dot-blot immunoassays are widely used for the user-friendly detection of clinical biomarkers. However, the majority of dot-blot assays have only limited sensitivity and are only used for qualitative or semiquantitative analysis. To overcome this limitation, we have employed labels based on photon-upconversion nanoparticles (UCNPs) that exhibit anti-Stokes luminescence and can be detected without optical background interference. First, the dot-blot immunoassay on a nitrocellulose membrane was optimized for the quantitative analysis of human serum albumin (HSA), resulting in a limit of detection (LOD) of 0.19 ng/mL and a signal-to-background ratio (S/B) of 722. Commercial quantum dots were used as a reference label, reaching the LOD of 4.32 ng/mL and the S/B of 3, clearly indicating the advantages of UCNPs. In addition, the potential of UCNP-based dot-blot for real sample analysis was confirmed by analyzing spiked urine samples, reaching the LOD of 0.24 ng/mL and recovery rates from 79 to 123%. Furthermore, we demonstrated the versatility and robustness of the assay by adapting it to the detection of two other clinically relevant biomarkers, prostate-specific antigen (PSA) and cardiac troponin (cTn), reaching the LODs in spiked serum of 9.4 pg/mL and 0.62 ng/mL for PSA and cTn, respectively. Finally, clinical samples of patients examined for prostate cancer were analyzed, achieving a strong correlation with the reference electrochemiluminescence immunoassay (recovery rates from 89 to 117%). The achieved results demonstrate that UCNPs are highly sensitive labels that enable the development of dot-blot immunoassays for quantitative analysis of low-abundance biomarkers.

Protein-templated copper nanoclusters for fluorimetric determination of human serum albumin.

Copper nanoclusters (CuNCs) are attractive for their unique optical properties, providing sensitive fluorescent detection of several kinds of targets even in complex matrices. Their ability in growing on suitable protein and nucleic acid templates make CuNCs efficient optical reporters to be exploited in bioanalysis. In this work, we report the specific and sensitive determination of human serum albumin (HSA) in human serum (HS) and urine via CuNCs fluorescence. HSA is the most abundant protein in plasma, and plays a key role in the early diagnosis of serious pathological conditions such as albuminuria and albuminemia. Recently, HSA has become clinically central also as a biomarker to assess severity, progression, and prognosis of various cancers. We report the controlled and reproducible growth of CuNCs directly on the target analyte, HSA, which results in a fine dose-dependent fluorescent emission at 405 nm. The protocol is optimized in water, and then applied to serum and urine specimens, without matrix pretreatment. The method linearly responds within the whole concentration of clinical interest, with a sensitivity of 1.8 ± 0.1 × 10-3 g L-1 and 0.62 ± 0.03 × 10-3 g L-1 in serum and urine, respectively, and excellent reproducibility (CVav% ca. 3% for both). The assay is designed to have a single protocol working for both matrices, with recovery of 95% (HS) and 96% (urine). The stability of the fluorescence after CuNCs formation was tested over 3 days, displaying good results (yet higher in urine than in serum).

Development and validation of point-of-care testing of albuminuria for early screening of chronic kidney disease.

INTRODUCTION: Chronic kidney disease (CKD) is a significant global health issue. As the prevalence of renal replacement therapy (RRT) in Thailand is increasing, early detection and management of CKD is the most important step to prevent CKD progression and the need for RRT. Current diagnostic tests for CKD are non-specific and expensive. We aimed to develop and validate antibody-based-albumin point-of-care testing (POCT) to detect patients with impaired kidney function at early stage. METHODS: The prototype strip test was developed under the concept of competitive lateral flow immunochromatography assay, or strip test. Monoclonal antibodies (MAbs) to human serum albumin (HSA) were harvested from the hybridomas of spleen cells from immunized mice and mouse myeloma cells. Presence of MAbs was detected by enzyme-linked immunosorbent assay (ELISA). Spot urine was obtained from patients with kidney disease, type I, or type II Diabetes Mellitus upon their visit at King Chulalongkorn Memorial Hospital during 2018-2019. All samples were analyzed for urine albumin with our POCT (CU microalbumin) and the other two commercial POCTs (Microalbu PHAN and MICRAL). The results were validated against standard method for urine microalbumin measurement. A urine microalbumin concentration of less than 20 ug/ml was defined as normal. The sensitivity, specificity, and predictive values were calculated in comparison with the standard laboratory method. RESULT: A total of 100 adult patients were included. CU microalbumin had a sensitivity of 86%, a specificity of 94%, and a positive predictive value of 96%. Our POCT showed good correlation with the laboratory results. CONCLUSION: CU microalbumin correlated well with the standard method for quantitative measurement of urine albumin. Therefore, it has the potential for early screening of CKD, especially in primary health care facilities in resource limited settings.

A novel hydrazide Schiff base self-assembled nanoprobe for selective detection of human serum albumin and its applications in renal disease surveillance.

Human serum albumin (HSA) is considered as a biomarker for the early diagnosis of renal disease, therefore identifying and detecting HSA in biological fluids (especially urine) with an easy method is of great importance. Herein, we report a novel hydrazide Schiff base fluorescent probe N'-((7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)pyrazine-2-carbohydrazide (NPC), which self-assembled into nanoparticles in aqueous solution. Based on disassembly-induced emission and the site-specific recognition mechanism, the binding of NPC with HSA resulted in a fluorescence "turn-on" response. Probe NPC exhibited superior selectivity and sensitivity toward HSA with a detection limit of 0.59 mg L-1 in PBS and 0.56 mg L-1 in the urine sample. The site-binding mechanism of NPC with HSA was explored by fluorescence quenching study, Job's plot analysis, HSA destruction, site marker displacement and molecular docking. Fluorescence imaging of HSA in MCF-7 cells was achieved by using a non-toxic NPC probe, suggesting that NPC could be applied to visualize the level of HSA in vivo. More importantly, further practical applications of probe NPC in human urine samples were achieved with satisfactory results by using a fluorometer or test paper, which could provide extensive application in clinical diagnosis.

NGAL, albumin and cystatin C during cisplatin therapy.

Cisplatin is a commonly used chemotherapeutic drugs. It is known for its nephrotoxic side effects with an increased risk of acute kidney injury. Finding of clinically feasible cisplatin nephrotoxicity markers is of importance. In our study, we compared neutrophil gelatinase-associated lipocalin (NGAL) in serum and urine, the estimated glomerular filtration rate (based on serum cystatin C) and urine albumin as markers of nephrotoxicity. The study involved 11 men and 9 women (mean ± SD age 58.2±9.5 years) with different malignancies treated with cisplatin in four cycles of chemotherapy (I - IV). Samples 0-4 were taken before, immediately after, in 3, 6 and 24 hours after administering chemotherapy. We detected significant increase of ACR in Sample 2 (p=0.03) and decrease of eGFR in Sample 4 (p=0.03) up to 24 hours after cisplatin administration in the first chemotherapy cycle only. When cumulative effect of cisplatin was assessed, significantly increased values of urine albumin (vs cycle I) were found in Sample 0 (p=0.00058), 1 (p=0.00256), 2 (p=0.00456), 3 (p=0.00006) and 4 (p=0.00319) in cycles II to IV. We found a correlation between values of urine NGAL and urine albumin (r=0.68, p<0.0001). In conclusion, urine albumin was the only measured marker that consistently and statistically significantly increased after cisplatin containing chemotherapy cycles.

Glyphosate exposures and kidney injury biomarkers in infants and young children.

The goal of this study was to assess biomarkers of exposure to glyphosate and assess potential associations with renal function in children. Glyphosate is used ubiquitously in agriculture worldwide. While previous studies have indicated that glyphosate may have nephrotoxic effects, few have examined potential effects on kidney function in children. We leveraged three cohorts across different phases of child development and measured urinary levels of glyphosate. We evaluated associations of glyphosate with three biomarkers of kidney injury: albuminuria (ACR), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury marker 1 (KIM-1). Multivariable regression analyses examined associations of glyphosate with kidney injury biomarkers controlling for covariates. We identified glyphosate in 11.1% of the total participants. The herbicide was detected more frequently in the neonate population (30%). Multivariable regression models failed to identify significant associations of log-transformed glyphosate with any of the kidney injury biomarkers, controlling for covariates age, sex, and maternal education. While we confirm detectability of glyphosate in children's urine at various ages and stages of life, there is no evidence in this study for renal injury in children exposed to low levels of glyphosate. Further studies of larger sample size are indicated to better understand putative deleterious effects of the herbicide after different levels of exposure.

Intrinsic and extrinsic epigenetic age acceleration are associated with hypertensive target organ damage in older African Americans.

BACKGROUND: Epigenetic age acceleration, a measure of biological aging based on DNA methylation, is associated with cardiovascular mortality. However, little is known about its relationship with hypertensive target organ damage to the heart, kidneys, brain, and peripheral arteries. METHODS: We investigated associations between intrinsic (IEAA) or extrinsic (EEAA) epigenetic age acceleration, blood pressure, and six types of organ damage in a primarily hypertensive cohort of 1390 African Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. DNA methylation from peripheral blood leukocytes was collected at baseline (1996-2000), and measures of target organ damage were assessed in a follow-up visit (2000-2004). Linear regression with generalized estimating equations was used to test for associations between epigenetic age acceleration and target organ damage, as well as effect modification of epigenetic age by blood pressure or sex. Sequential Oligogenic Linkage Analysis Routines (SOLAR) was used to test for evidence of shared genetic and/or environmental effects between epigenetic age acceleration and organ damage pairs that were significantly associated. RESULTS: After adjustment for sex, chronological age, and time between methylation and organ damage measures, higher IEAA was associated with higher urine albumin to creatinine ratio (UACR, p = 0.004), relative wall thickness (RWT, p = 0.022), and left ventricular mass index (LVMI, p = 0.007), and with lower ankle-brachial index (ABI, p = 0.014). EEAA was associated with higher LVMI (p = 0.005). Target organ damage associations for all but IEAA with LVMI remained significant after further adjustment for blood pressure and antihypertensive use (p < 0.05). Further adjustment for diabetes attenuated the IEAA associations with UACR and RWT, and adjustment for smoking attenuated the IEAA association with ABI. No effect modification by age or sex was observed. CONCLUSIONS: Measures of epigenetic age acceleration may help to better characterize the functional mechanisms underlying organ damage from cellular aging and/or hypertension. These measures may act as subclinical biomarkers for damage to the kidney, heart, and peripheral vasculature; however more research is needed to determine whether these relationships remain independent of lifestyle factors and comorbidities.

Identification of 22 novel loci associated with urinary biomarkers of albumin, sodium, and potassium excretion.

Urine biomarkers reflecting kidney function and handling of dietary sodium and potassium are strongly associated with several common diseases including chronic kidney disease, cardiovascular disease, and diabetes mellitus. Knowledge about the genetic determinants of these biomarkers may shed light on pathophysiological mechanisms underlying the development of these diseases. We performed genome-wide association studies of urinary albumin: creatinine ratio (UACR), urinary potassium: creatinine ratio (UK/UCr), urinary sodium: creatinine ratio (UNa/UCr) and urinary sodium: potassium ratio (UNa/UK) in up to 218,450 (discovery) and 109,166 (replication) unrelated individuals of European ancestry from the UK Biobank. Further, we explored genetic correlations, tissue-specific gene expression, and possible genes implicated in the regulation of these biomarkers. After replication, we identified 19 genome-wide significant independent loci associated with UACR, 6 each with UK/UCr and UNa/UCr, and 4 with UNa/UK. In addition to 22 novel associations, we confirmed several established associations, including between the CUBN locus and microalbuminuria. We detected high pairwise genetic correlation across the urinary biomarkers, and between their levels and several physiological measurements. We highlight GIPR, a potential diabetes drug target, as possibly implicated in the genetic control of urinary potassium excretion, and NRBP1, a locus associated with gout, as plausibly involved in sodium and albumin excretion. Overall, we identified 22 novel genome-wide significant associations with urinary biomarkers and confirmed several previously established associations, providing new insights into the genetic basis of these traits and their connection to chronic diseases.

Electrochemical Quantification of Glycated and Non-glycated Human Serum Albumin in Synthetic Urine.

A polymer-based electrode capable of specific detection of human serum albumin, and its glycated derivatives, is described. The sensor is constructed from a glass microscope slide coated with a synthesized, polythiophene film bearing a protected, iminodiacetic acid motif. The electrode surface is then further elaborated to a functional biosensor through deprotection of the iminodiacetic acid, followed by metal-affinity immobilization of a specific and high-affinity, albumin ligand. Albumin was then quantified in buffer and synthetic urine via electrochemical impedance spectroscopy. Glycated albumin was next bound to a boronic acid-modified, single-cysteine dihydrofolate reductase variant to quantify glycation ratios by square-wave voltammetry. The platform offers high sensitivity, specificity, and reproducibility in an inexpensive arrangement. The detection limits exceed the requirements for intermediate-term glycemic control monitoring in diabetes patients at 5 and 1 nM for albumin and its glycated forms, respectively.

Assessing urinary levels of IL-18, NGAL and albumin creatinine ratio in patients with diabetic nephropathy.

AIMS: Diabetic nephropathy (DN) is a serious microvascular complication of a longstanding hyperglycemia. This study aims to evaluate whether urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary Interleukin-18 possess a better diagnostic value than albumin creatinine ratio in assessing the severity of nephropathy in patients with type 2 diabetes mellitus (T2DM). MATERIAL & METHODS: Ninety participants diagnosed with T2DM were recruited and they were divided into three study groups according to their albumin/creatinine ratio (ACR): (Normoalbuminuria group, Microalbuminuria group, and Macroalbuminuria group). A matching of Ninety healthy subjects were included as controls. Blood and urine samples were collected to measure various markers of glycemic control and kidney function. RESULTS: IL-18 levels were not changed significantly between all study groups (P > 0.05), despite a significant positive correlation between IL-18 and urinary albumin levels. NGAL levels were significantly increased in Microalbuminuria group and Macroalbuminuria group as compared to the control and Normoalbuminuria groups. NGAL was also positively correlated with urinary albumin and ACR, but negatively correlated with the age and body mass index. Receiver Operating Characteristic curves revealed that for early detection of DN, the best cutoff values to discriminate DN and diabetic without nephropathy groups were ˃ 21.4 ng/ml for NGAL (94.67 sensitivity, 26.67% specificity), ≤0.34 pg/mL for IL-18 (72% sensitivity, 53.33% specificity), and ˃29.8 mg/g for ACR (80% sensitivity, 100% specificity). CONCLUSION: We conclude that the urinary ACR is a more accurate individual biomarker of DN when compared to both NGAL and IL-18.

Discovery and Qualification of Candidate Urinary Biomarkers of Disease Activity in Lupus Nephritis.

Lupus nephritis (LN) is a severe clinical manifestation of systemic lupus erythematosus (SLE) associated with significant morbidity and mortality. Assessment of severity and activity of renal involvement in SLE requires a kidney biopsy, an invasive procedure with limited prognostic value. Noninvasive biomarkers are needed to inform treatment decisions and to monitor disease activity. Proteinuria is associated with disease progression in LN; however, the composition of the LN urinary proteome remains incompletely characterized. To address this, we profiled LN urine samples using complementary mass spectrometry-based methods:  protein gel fractionation, chemical labeling using tandem mass tags, and data-independent acquisition. Combining results from these approaches yielded quantitative information on 2573 unique proteins in urine from LN patients. A multiple-reaction monitoring (MRM) method was established to confirm eight proteins in an independent cohort of LN patients, and seven proteins (transferrin, α-2-macroglobulin, haptoglobin, afamin, α-1-antitrypsin, vimentin, and ceruloplasmin) were confirmed to be elevated in LN urine compared to healthy controls. In this study, we demonstrate that deep mass spectrometry profiling of a small number of patient samples can identify high-quality biomarkers that replicate in an independent LN disease cohort. These biomarkers are being used to inform clinical biomarker strategies to support longitudinal and interventional studies focused on evaluating disease progression and treatment efficacy of novel LN therapeutics.

Normothermic versus hypothermic cardiopulmonary bypass in low-risk paediatric heart surgery: a randomised controlled trial.

OBJECTIVE: To compare normothermic (35°C-36°C) versus hypothermic (28°C) cardiopulmonary bypass (CPB) in paediatric patients undergoing open heart surgery to test the hypothesis that normothermic CPB perfusion maintains the functional integrity of major organ systems leading to faster recovery. METHODS: Two single-centre, randomised controlled trials (known as Thermic-1 and Thermic-2, respectively) were carried out to compare the effectiveness and acceptability of normothermic versus hypothermic CPB in children with congenital heart disease undergoing open heart surgery. In both studies, the co-primary clinical outcomes were duration of inotropic support, intubation time and postoperative hospital stay. RESULTS: In total, 200 participants were recruited; 59 to the Thermic-1 study and 141 to the Thermic-2 study. 98 patients received normothermic CPB and 102 patients received hypothermic CPB. There were no significant differences between the treatment groups for any of the co-primary outcomes: inotrope duration HR=1.01, 95% CI (0.72 to 1.41); intubation time HR=1.14, 95% CI (0.86 to 1.51); postoperative hospital stay HR=1.06, 95% CI (0.80 to 1.40). Differences favouring normothermia were found in urea nitrogen at 2 days geometric mean ratio (GMR)=0.86 95% CI (0.77 to 0.97); serum creatinine at 3 days GMR=0.89, 95% CI (0.81 to 0.98); urinary albumin at 48 hours GMR=0.32, 95% CI (0.14 to 0.74) and neutrophil gelatinase-associated lipocalin at 4 hours GMR=0.47, 95% CI (0.22 to 1.02), but not at other postoperative time points. CONCLUSIONS: Normothermic CPB is as safe and effective as hypothermic CPB and can be routinely adopted as a perfusion strategy in low-risk infants and children undergoing open heart surgery. TRIAL REGISTRATION NUMBER: ISRCTN93129502.

Urine afamin and afamin-creatinine ratio as biomarkers for kidney injury.

AIM: The aim of this study was to evaluate the urine afamin (uAFM) and afamin-creatinine ratio (AfCR) levels in patients with glomerulonephritis. PATIENTS & METHODS: We determined uAFM and AfCR of 247 healthy volunteers and 129 biopsy-proven glomerulonephritis patients. RESULTS: Analytical evaluation study revealed the assay is a reliable and robust test for measuring uAFM. For reference intervals, uAFM and AfCR values were different significantly between males and females. uAFM and AfCR levels were significantly increased in patients with primary membranous nephropathy, IgA nephropathy and minimal change disease compared with healthy volunteers. uAFM and AfCR were positively correlated with urine albumin and albumin-creatinine ratio, respectively. CONCLUSION: Our study suggested that uAFM and AfCR may be attractive biomarkers for kidney injury.

Prevalence of normoalbuminuric renal insufficiency and associated clinical factors in adult onset diabetes.

BACKGROUND: Microalbuminuria signifies the onset of diabetic nephropathy, but normoalbuminuric patients with diabetes who have a low Glomerular Filtration Rate (GFR) are not uncommon. The purpose of the study was to estimate the prevalence of such patients and to assess the clinical correlates. METHODS: Cross-sectional study included patients with diabetes attending medical clinics at Teaching Hospital Galle. Diagnosis of albuminuria was made if urinary albumin excretion was > 30 mg/g of creatinine in two out of three samples. Patients were stratified into chronic kidney disease stages according to the estimated GFR (eGFR) calculated by Modification of Diet in Renal Disease (MDRD). RESULTS: Mean (SD) age and duration of the disease of 456 (348 females) patients with diabetes were 60 (12) years and 10 (4) years. Sixty (13.2%) patients had low eGFR and 26.7% of them had normoalbuminuria. In the total sample, the proportion of patients with low eGFR and normoalbuminuria was 16 (3.5%). Among the patients with normoalbuminuria and low eGFR, 12.5% had retinopathy and none had any form neuropathy. When age, duration of disease, systolic and diastolic blood pressures, smoking, glycaemic control, presence of hypertension and ischaemic heart disease were included in binary logistic regression model, only age was found to be significant different (OR = 1.1, P = 0.03). CONCLUSION: A considerable proportion of adult diabetics are normoalbuminuric despite low eGFR. This limits the role of microalbuminuria as a screening tool to detect the onset of diabetic nephropathy. These patients do not exhibit distinct clinical features that facilitate identification of them using clinical information.

Albuminuria Increases the Risks for Both Alzheimer Disease and Vascular Dementia in Community-Dwelling Japanese Elderly: The Hisayama Study.

BACKGROUND: Epidemiologic evidence has emerged to reveal an association of albuminuria and low estimated glomerular filtration rate (eGFR) with dementia, but the findings are inconsistent. In addition, there are limited studies addressing the association between albuminuria and Alzheimer disease (AD). METHODS AND RESULTS: A total of 1562 community-dwelling Japanese subjects aged ≥60 years without dementia were followed up for 10 years. The outcomes were incidence of all-cause dementia and its subtypes, namely, AD and vascular dementia (VaD). The hazard ratios for the outcomes were estimated according to urine albumin-creatinine ratio (UACR) and eGFR levels using a Cox proportional hazards model. During the follow-up, 358 subjects developed all-cause dementia (238 AD and 93 VaD). Higher UACR level was significantly associated with greater multivariable-adjusted risks of all-cause dementia (hazard ratios [95% confidence intervals]: 1.00 [reference], 1.12 [0.78-1.60], 1.65 [1.18-2.30], and 1.56 [1.11-2.19] for UACR of ≤6.9, 7.0-12.7, 12.8-29.9, and ≥30.0 mg/g, respectively), AD (1.00 [reference], 1.20 [0.77-1.86], 1.75 [1.16-2.64], and 1.58 [1.03-2.41], respectively), and VaD (1.00 [reference], 1.03 [0.46-2.29], 1.94 [0.96-3.95], and 2.19 [1.09-4.38], respectively). On the other hand, lower eGFR level was marginally associated with greater risk of VaD, but not AD. Subjects with UACR ≥12.8 mg/g and eGFR of <60 mL/min per 1.73 m2 had 3.3-fold greater risk of VaD than those with UACR <12.8 mg/g and eGFR of ≥60 mL/min per 1.73 m2. CONCLUSIONS: Albuminuria is a significant risk factor for the development of both AD and VaD in community-dwelling Japanese elderly. Moreover, albuminuria and low eGFR are mutually associated with a greater risk of VaD.

Hemoglobin, Albuminuria, and Kidney Function in Cardiovascular Risk: The ARIC (Atherosclerosis Risk in Communities) Study.

BACKGROUND: Reduced estimated glomerular filtration rate (eGFR) and elevated urinary albumin-to-creatinine ratio (ACR) individually increase risk of cardiovascular disease (CVD). We hypothesized that these associations are stronger among people with abnormal (both low and high) hemoglobin levels. METHODS AND RESULTS: Using 5801 participants with available hemoglobin measures of the ARIC (Atherosclerosis Risk in Community) study in 1996-1998, we explored the cross-sectional association of eGFR and ACR with hemoglobin levels and their longitudinal associations with CVD (heart failure, coronary heart disease, and stroke) risk through 2013. At baseline, 8.8% had anemia (<13 g/dL in men and <12 g/dL in women) and 7.2% had high hemoglobin (≥16 g/dL in men and ≥15 g/dL in women). The adjusted prevalence ratio of anemia was 2.12 (95% confidence interval, 1.59-2.82) for eGFR 30 to 59 compared with ≥90 mL/min per 1.73 m2 and 1.45 (1.07-1.95) for ACR ≥30 compared with <10 mg/g. ACR ≥30 mg/g was also associated with high hemoglobin (prevalence ratio, 1.57 [1.12-2.19] compared with <10 mg/g). During follow-up, there were 1069 incident CVDs among 5098 CVD-free participants at baseline. In multivariable Cox models, lower eGFR, higher ACR, and anemia were each independently associated with CVD risk, with the association of low eGFR being slightly stronger in anemia (P-for-interaction, 0.072). There was no hemoglobin-ACR interaction; however, when CVD subtypes were analyzed separately, risk of coronary heart disease and stroke associated with high ACR was slightly stronger in high hemoglobin (P-for-interaction, 0.074). CONCLUSIONS: Kidney function, albuminuria, and anemia were correlated and independently associated with CVD risk. Correlation and potential interaction for atherosclerotic CVD between albuminuria and high hemoglobin deserve further investigation.

Evaluation of clinically available renal biomarkers in critically ill adults: a prospective multicenter observational study.

BACKGROUND: Although serum cystatin C (sCysC), urinary N-acetyl-ß-D-glucosaminidase (uNAG), and urinary albumin/creatinine ratio (uACR) are clinically available, their optimal combination for acute kidney injury (AKI) detection and prognosis prediction remains unclear. We aimed to assess the discriminative abilities of these biomarkers and their possible combinations for AKI detection and intensive care unit (ICU) mortality prediction in critically ill adults. METHODS: A multicenter, prospective observational study was conducted in mixed medical-surgical ICUs at three tertiary care hospitals. One thousand eighty-four adult critically ill patients admitted to the ICUs were studied. We assessed the use of individual biomarkers (sCysC, uNAG, and uACR) measured at ICU admission and their combinations with regard to AKI detection and prognosis prediction. RESULTS: AUC-ROCs for sCysC, uNAG, and uACR were calculated for total AKI (0.738, 0.650, and 0.683, respectively), severe AKI (0.839, 0.706, and 0.771, respectively), and ICU mortality (0.727, 0.793, and 0.777, respectively). The panel of sCysC plus uNAG detected total and severe AKI with significantly higher accuracy than either individual biomarkers or the other two panels (uNAG plus uACR or sCysC plus uACR). For detecting total AKI, severe AKI, and ICU mortality at ICU admission, this panel yielded AUC-ROCs of 0.756, 0.863, and 0.811, respectively; positive predictive values of 0.71, 0.31, and 0.17, respectively; and negative predictive values of 0.81, 0.97, and 0.98, respectively. Moreover, this panel significantly contributed to the accuracy of the clinical models for AKI detection and ICU mortality prediction, as measured by the AUC-ROC, continuous net reclassification index, and incremental discrimination improvement index. The comparable performance of this panel was further confirmed with bootstrap internal validation. CONCLUSIONS: The combination of a functional marker (sCysC) and a tubular damage marker (uNAG) revealed significantly superior discriminative performance for AKI detection and yielded additional prognostic information on ICU mortality.

Evaluation of the Relationship Between Microalbuminuria and Urine Ischemia-Modified Albumin Levels in Patients with Diabetic Nephropathy.

INTRODUCTION: Ischemia-modified albumin (IMA) is a marker which can be associated with oxidative stress in various ischemic and non-ischemic processes. Oxidative stress plays roles in diabetes mellitus, its complications and pathogenesis. Serum IMA levels are examined in various clinical events. However, urine IMA levels have not yet been evaluated in diabetic patients. In this study, we aim to examine the relationship between metabolic features and urine microalbuminuria levels of diabetic patients and their urine IMA levels. MATERIALS AND METHODS: There were totally 50 type 2 diabetic patients in the study at the Mevlana University Hospital. Patients with cerebrovascular disease, acute myocardial infarction, hemodialysis patients with end stage chronic renal failure, pulmonary embolism, and malignant disease were excluded from the study. Metabolic features, urine IMA levels and cardiological parameters of patients were evaluated. RESULTS: Mean age of patients was 59 ± 9 years, 20 of them (40%) were male and 30 of them (60%) were female. There were six patients with albuminuria value of <0.03 mg/g (normal), there were 39 patients with microalbuminuria value of 0.03-0.3 mg/g and there were five patients with macroalbuminuria of >0.3 mg/g. According to the analysis of patients with microalbuminuria (n = 39), there was no correlation between IMA levels and numerical demographic data, albuminuria, glucose, HbA1c, lipid profile, creatinine, uric acid, hematological parameters. DISCUSSION: Conclusively, there was no relationship between urine IMA levels and microalbuminuria related to the diabetic nephropathy. These findings can be associated with urinary excretion mechanisms of IMA.