Biomarkers Of Acute Kidney Injury Research Articles

Can Novel Biomarkers Effectively Predict Acute Kidney Injury in Liver or Kidney Transplant Recipients?

Acute kidney injury (AKI) constitutes a common complication associated with liver or kidney transplantation, which may significantly impact the graft condition and perioperative mortality. Current AKI diagnostic criteria based on serum creatinine (sCr) and urine output alterations are widely utilized in routine clinical practice. However, the diagnostic value of sCr may be limited by various confounding factors, including age, sex, reduced or increased muscle mass, and pre-existing chronic kidney disease (CKD). Furthermore, sCr is rather a late indicator of AKI, as its concentration tends to increase only when the severity of the injury is enough to decrease the estimated glomerular filtration rate (eGFR). Recent expertise highlights the need for novel biomarkers in post-transplantation AKI diagnosis, prediction of event-associated mortality, or evaluation of indications for renal replacement treatment (RRT). Over the last decade, the diagnostic performance of various AKI biomarkers has been assessed, among which some showed the potential to outperform sCr in AKI diagnosis. Identifying susceptible individuals, early diagnosis, and prompt intervention are crucial for successful transplantation, undisturbed graft function in long-term follow-up, and decreased mortality. However, the research on AKI biomarkers in transplantation still needs to be explored. The field lacks consistent results, rigorous study designs, and external validation. Considering the rapidly growing prevalence of CKD and cirrhosis that are associated with the transplantation at their end-stage, as well as the existing knowledge gap, the aim of this article was to provide the most up-to-date review of the studies on novel biomarkers in the diagnosis of post-transplantation AKI.

Serum uromodulin associates with kidney function and outcome in a cohort of hospitalised COVID-19 patients

This study investigates the prevalence and evaluates the prognostic implications of acute kidney injury (AKI) in COVID-19 patients, with a novel emphasis on the evaluation of serum uromodulin (sUmod) as a potential kidney-specific biomarker. A cohort of hospitalised COVID-19 patients (n = 378) was examined for AKI using standard criteria. In addition to traditional urinary biomarkers, sUmod levels were analysed. Univariable and multivariable regression models were employed to evaluate the association of sUmod and AKI and in-hospital mortality. Levels of sUmod were significantly lower in patients with CKD (91.8 ± 60.7 ng/ml) compared to patients with normal kidney function (204.7 ± 91.7 ng/ml; p < 0.001). 151 patients (40.0%) presented with AKI at the time of hospital admission or developed an AKI during hospitalization. 116 patients (76.8%) had an AKI already at the time of hospital admission. COVID-19 patients with AKI had significantly lower levels of sUmod compared to patients without AKI during hospitalisation (124.8 ± 79.5 ng/ml) vs 214.6 ± 92.3 ng/ml; p < 0.001). The in-hospital mortality rate in this cohort of COVID-19 patients was 15.3%. Patients with AKI had a higher probability for in-hospital death (OR 5.6, CI 1.76 to 17.881, p = 0.004). Patients who died during hospital stay, had significantly lower sUmod levels (129.14 ± 89.56 ng/ml) compared to patients surviving hospitalisation (187.71 ± 96,64 ng/ml; p < 0.001). AKI is frequently associated with COVID-19 in hospitalized patients. Serum uromodulin may emerge as a promising biomarker for AKI in COVID-19 patients. Further research is warranted to explore its clinical application and refine risk stratification in this patient population.

Proenkephalin A 119-159 in Perioperative and Intensive Care-A Promising Biomarker or Merely Another Option?

Acute kidney injury (AKI) is a severe and prevalent syndrome, primarily observed in intensive care units (ICUs) and perioperative settings. The discovery of a new biomarker for kidney function and injury, capable of overcoming the limitations of traditional markers, has the potential to improve the diagnosis and management of AKI. Proenkephalin A 119-159 (PENK) has emerged as a novel biomarker for AKI and has been validated in various clinical settings. It has demonstrated a faster response to AKI compared to creatinine and has been shown to predict successful weaning from renal replacement therapy in the ICU. PENK has also shown promise as an AKI biomarker in perioperative patients. Additionally, PENK has been proven to be effective in estimating mortality and morbidity in patients undergoing cardiac surgery, and those with traumatic brain injury or ischemic stroke. Incorporating PENK into a novel estimation of the glomerular filtration rate, referred to as the PENK-Crea equation, has yielded promising results.

Urinary Neutrophil Gelatinase-Associated Lipocalin Values in Preterm Neonates: A Systematic Review and Meta-analysis.

Acute kidney injury (AKI) is common in hospitalized preterm neonates. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a promising noninvasive AKI biomarker. However, normal values of uNGAL in preterm neonates without AKI are poorly characterized. The objective of this study was to evaluate the current literature to determine normal uNGAL values for preterm neonates without AKI. Systematic review and meta-analysis of all articles published before November 2021 evaluating uNGAL values in preterm neonates without AKI. Of 1,607 studies evaluated for eligibility, 11 were included in the final meta-analysis (210 males, 202 females). uNGAL values were higher in the preterm neonates <29 weeks and ranged between 20.7 and 782.65 ng/mL. Meta mean estimates of gestational age (GA), birthweight, and neutrophil gelatinase-associated lipocalin were 29.4 weeks (95% confidence interval [CI]: 28.8-30.0), 1,241 g (95% CI: 1,111-1,372), and 148.9 ng/mL (95% CI: 48-231), respectively. In limited studies, a wide range of uNGAL values in preterm neonates without AKI are reported. Future studies should identify normal uNGAL values in preterm neonates using larger cohorts by GA and birthweight. · Urinary NGAL is a promising noninvasive biomarker of neonatal AKI.. · A wide range of uNGAL is reported in preterm neonates but the baseline values are not well defined.. · Urine NGAL values are higher in extremely preterm compared with preterm neonates..

Acute kidney injury due to gentamicin nephrotoxicity and specific miRNAs as biomarkers.

Acute kidney injury (AKI) due to gentamicin nephrotoxicity is a significant concern in clinical medicine, particularly in patients receiving prolonged or high-dose gentamicin therapy. Gentamicin is an aminoglycoside antibiotic frequently used in the treatment of a range of bacterial infections. However, its use is associated with nephrotoxicity which can manifest as AKI. Due to this, it is crucial to diagnose promptly and manage treatment effectively. Ongoing studies are therefore focusing on non-protein-coding RNAs as potential biomarkers for AKI. Numerous microRNAs (miRNAs) have been implicated in gentamicin-induced nephrotoxicity and AKI. They participate in pathways associated with inflammation, cell death, and oxidative stress and each of these factors play critical roles in the development of gentamicin-induced kidney injury. Research studies have demonstrated changes in the expression levels of these miRNAs in response to gentamicin exposure both in vitro and in in vivo models, as well as in human clinical trials involving patients receiving gentamicin therapy. The dysregulation of these miRNAs correlates with the severity of kidney injury and may serve as sensitive biomarkers for early detection and monitoring of AKI induced by gentamicin.

Urinary L-FABP Assay in the Detection of Acute Kidney Injury following Haematopoietic Stem Cell Transplantation.

Background: Acute Kidney Injury (AKI) is a condition that affects a significant proportion of acutely unwell patients and is associated with a high mortality rate. Patients undergoing haemopoietic stem cell transplantation (HSCT) are in an extremely high group for AKI. Identifying a biomarker or panel of markers that can reliably identify at-risk individuals undergoing HSCT can potentially impact management and outcomes. Early identification of AKI can reduce its severity and improve prognosis. We evaluated the urinary Liver type fatty acid binding protein (L-FABP), a tubular stress and injury biomarker both as an ELISA and a point of care (POC) assay for AKI detection in HSCT. Methods: 85 patients that had undergone autologous and allogenic HSCT (35 and 50, respectively) had urinary L-FABP (uL-FABP) measured by means of a quantitative ELISA and a semi-quantitative POC at baseline, day 0 and 7 post-transplantation. Serum creatinine (SCr) was also measured at the same time. Patients were followed up for 30 days for the occurrence of AKI and up to 18 months for mortality. The sensitivity and specificity of uL-FABP as an AKI biomarker were evaluated and compared to the performance of sCr using ROC curve analysis and logistic regression. Results: 39% of participants developed AKI within 1 month of their transplantation. The incidence of AKI was higher in the allogenic group than in the autologous HTSC group (57% vs. 26%, p = 0.008) with the median time to AKI being 25 [range 9-30] days. This group was younger (median age 59 vs. 63, p < 0.001) with a lower percentage of multiple myeloma as the primary diagnosis (6% vs. 88%, p < 0.001). The median time to AKI diagnosis was 25 [range 9-30] days. uL-FABP (mcg/gCr) at baseline, day of transplant and on the 7th day post-transplant were 1.61, 5.39 and 10.27, respectively, for the allogenic group and 0.58, 4.36 and 5.14 for the autologous group. Both SCr and uL-FABP levels rose from baseline to day 7 post-transplantation, while the AUC for predicting AKI for baseline, day 0 and day 7 post-transplant was 0.54, 0.59 and 0.62 for SCr and for 0.49, 0.43 and 0.49 uL-FABP, respectively. Univariate logistic regression showed the risk of AKI to be increased in patients with allogenic HSCT (p = 0.004, 95%CI [0.1; 0.65]) and in those with impaired renal function at baseline (p = 0.01, 95%CI [0.02, 0.54]). The risk of AKI was also significantly associated with SCr levels on day 7 post-transplant (p = 0.03, 95%CI [1; 1.03]). Multivariate logistic regression showed the type of HSCT to be the strongest predictor of AKI at all time points, while SCr levels at days 0 and 7 also correlated with increased risk in the model that included uL-FABP levels at the corresponding time points. The POC device for uL-FABP measurement correlated with ELISA (p < 0.001, Spearman 'correlation' = 0.54) Conclusions: The urinary biomarker uL-FABP did not demonstrate an independent predictive value in the detection of AKI at all stages. The most powerful risk predictor of AKI in this setting appears to be allograft recipients and baseline renal impairment, highlighting the importance of clinical risk stratification. Urinary L-FAPB as a POC biomarker was comparable to ELISA, which provides an opportunity for simple and rapid testing. However, the utility of LFABP in AKI is unclear and needs further exploration. Whether screening through rapid testing of uL-FABP can prevent or reduce AKI severity is unknown and merits further studies.

Fabrication of ultra-sensitive and disposable electrochemical biosensor: Detection of kidney injury molecule-1 protein in urine for diagnosis of kidney injury

This research study indicates the development of the indium tin oxide-polyethylene terephthalate (ITO-PET) coated electrode-based electrochemical biosensor system to sensitively and specifically detect kidney injury molecule-1 (KIM-1), an acute kidney injury (AKI) biomarker. The ITO-PET electrode surface was modified with 3-(Trimethoxysilyl)-1-propanethiol (3-TMESP) silane agent. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and single frequency impedance (SFI) techniques were utilized to examine the interactions between anti-KIM-1 antibody and KIM-1 antigen. The ITO-PET electrode surface was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to analyze the morphological characterization at each electrode development stage. Optimization studies have been conducted to determine the optimal concentrations for detecting the 3-TMESP silane agent, the NHS crosslinker, the anti-KIM-1 antibody, and the optimum incubation period for the anti-KIM-1 antibody and the KIM-1 antigen. Analytical characteristic properties of the developed biosensor, including linear determination range, and the studies of reproducibility, regeneration, repeatability, storage life, and selectivity were investigated. The KIM-1 biosensor system, based on 3-TMESP, has a broad linear range and is capable of providing sensitive measurements between 0.1 fg/mL and 1000 fg/mL. The values of low limits of detection (0.26 fg/mL) and of quantification (0.87 fg/mL) were calculated, highlighting its high sensitivity and precision in detecting KIM-1. In addition, five different commercially purchased human urine samples were tested to validate the practicability of the developed biosensor.

A-106 Determination of Urinary NGAL Reference Intervals from Specimens of Healthy Adult and Pediatric Individuals

Abstract Background Neutrophil gelatinase-associated lipocalin (NGAL) is a 25kDa protein implicated in multiple biological processes, including attenuation of apoptosis and differentiation of renal tubule epithelial cells and nephrons. NGAL is also produced and secreted by injured kidney tubule epithelial cells. As such, NGAL can serve as an early urinary biomarker for acute kidney injury (AKI). This multi-site, cross-sectional study aimed to establish reference intervals for urinary NGAL (uNGAL) in healthy pediatric and adult populations using a particle-enhanced turbidimetric assay. Methods Apparently healthy individuals, aged ≥ 3 months, were eligible for this study. Subjects with an active urinary tract infection (UTI) on the day of sample collection, acute kidney injury (AKI) or a history of AKI, stage 4 or 5 chronic kidney disease (CKD), known congenital anomalies of the kidney and urinary tract, known urothelial, urological, or kidney malignancies were excluded from the study. Subjects with uncorrected congenital heart disease, having undergone solid organ or bone marrow transplantation, receiving renal replacement therapy, and having undergone surgery (urologic, nephrectomy, or correction of congenital heart disease) were also excluded. A total of 688 subjects were screened, 677 were eligible, and 629 (91.4%) were considered evaluable per the protocol. The 59 excluded subjects were ineligible due to missing/incorrect information in the informed consent form, or not evaluable due to meeting exclusion criteria, mostly a positive UTI test. Urine samples were tested for NGAL on a Roche cobas® c501 analyzer in single determinations. Results Tables 1 and 2 describe the NGAL summary statistics and central 95% reference intervals by age and gender. Conclusions These data demonstrate the normal urine NGAL values in an apparently healthy pediatric and adult populations.

A-309 Multicenter Performance Evaluation of the ProNephro AKITM Assay and Sample Stability in Pediatric Patients

Abstract Background Acute Kidney Injury (AKI), defined by increased serum creatinine or decreased urine volume, is highly prevalent in critically ill pediatric patients. Those who develop AKI experience worsened outcomes, raising the need for accurate and early biomarkers for AKI. Relying in serum creatinine for AKI diagnosis is unreliable due to its diagnostic inaccuracy and delayed rise in the AKI pathophysiology. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a novel and widely studied biomarker for early identification of AKI. During pathological progression, NGAL is elevated in blood and urine within two hours of the insult, making it useful for early diagnosis and management of kidney injury in critically ill children. This study aims at evaluating the performance characteristics of a quantitative test for NGAL in urine intended for use in critically ill pediatric patients, and investigating the stability of NGAL in pediatric urine. Methods The ProNephroAKITM is a particle-enhanced turbidimetric immunoassay on the Roche cobas® c501 analyzer to measure NGAL quantitatively in urine in pediatric patients 3 months to 21 years of age. These studies were approved by the respective institutional review boards. The limits of blank (LOB), detection (LOQ) and quantitation (LOQ) were determined following CLSI EP17A2. Linearity was assessed across the measurement range (MR) of 50-3000 ng/mL. The assay repeatability, between-run, between-day and total imprecision were determined in pediatric urine samples (n=9, covering the MR) and controls (n=2) following CLSI EP5-03 guidelines. Likewise, multisite reproducibility was evaluated in pediatric urine (n=7, covering the MR) and controls (n=2) in 3 laboratories and alternating operators. The assay specificity was assessed in the presence of several endogenous and exogeneous substances (e.g. drugs, contrast agents), potential related cross-reactant molecules, and several pH-values. The stability of NGAL in urine was evaluated using freshly collected pediatric urine samples covering the MR from 16 consented patients after storage at ambient (15-30°C), refrigerated (2-8°C), and frozen temperatures (≤-70°C), and following 3 freeze/thaw cycles. Results The ProNephroAKITM is linear across the MR of 50-3000 ng/mL. The LOB, LOD and LOQ were 9, 14 and 18 ng/mL, respectively. The coefficients of variation (CVs) for repeatability, between-run, between-day and total precision were ≤5.0%, ≤3.1%, ≤1.7% and ≤4.9%, respectively in urine and control samples. The reproducibility across 3 independent laboratories was ≤6.6%. The recovery of NGAL was not significantly affected by endogenous substances, contrast agents, pH (3.3-10.3), and common and special pharmaceutical compounds (exception: very high Cefepime concentrations may decrease NGAL), and potential cross-reactants. Freshly collected urine samples spanning concentrations from 71-2,373 ng/mL were stable (±10% recovery) for 2 days at ambient, 4 days refrigerated and 13 months frozen, and after 3 freeze/thaw cycles. Conclusions We report the performance characteristics of the ProNephroAKITM assay, including excellent precision and adequate reproducibility across 3 laboratories, sensitivity, specificity, and urine sample stability. The test was determined to meet the analytical performance required for clinical use in critically ill pediatric patients at risk of developing or having persistent AKI.

Biomarkers of acute kidney injury: a concise review of current literature

Abstract Background Acute kidney injury (AKI), a medical condition associated with increased hospitalization rates which requires interdisciplinary management, is a major health concern because of the burden it places on the health systems of different countries. Biomarkers represent the focus of recent years in furthering the early diagnosis of AKI, providing new opportunities for correct prophylaxis or early therapeutic intervention so that the evolution of patients with this pathology is favorable and the risk of life-threatening complications is negligible. Methods We performed an extensive literature search on PubMed and ScienceDirect databases, using keywords related to bio-markers for AKI. We searched for acute kidney injury (AKI), cystatin C (CYS-C), galectin-3 (GAL-3), kidney injury molecule-1 (KIM-1), neutrophil-gelatinase-associated lipocalin (NGAL), interleukin-8 (IL-8), and liver-type fatty acid-binding protein (L-FABP). We included a high number of papers, with an emphasis on more recent publications. Results Studies that analyzed the biomarkers for AKI show that CYS-C, GAL-3, KIM-1, NGAL, IL-8, calprotectin, and proteinuria were noted as potential biomarkers for early diagnosis of AKI. Conclusions Biomarkers represent the focus of recent years in furthering an early diagnosis of AKI, providing new opportunities for correct prophylaxis or early therapeutic intervention.

An early and stable mouse model of polymyxin-induced acute kidney injury

BackgroundPolymyxins have been revived as a last-line therapeutic option for multi-drug resistant bacteria and continue to account for a significant proportion of global antibiotic usage. However, kidney injury is often a treatment limiting event with kidney failure rates ranging from 5 to 13%. The mechanisms underlying polymyxin-induced nephrotoxicity are currently unclear. Researches of polymyxin-associated acute kidney injury (AKI) models need to be more standardized, which is crucial for obtaining consistent and robust mechanistic results.MethodsIn this study, male C57BL/6 mice received different doses of polymyxin B (PB) and polymyxin E (PE, also known as colistin) by different routes once daily (QD), twice daily (BID), and thrice daily (TID) for 3 days. We continuously monitored the glomerular filtration rate (GFR) and the AKI biomarkers, including serum creatinine (Scr), blood urea nitrogen (BUN), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1). We also performed histopathological examinations to assess the extent of kidney injury.ResultsMice receiving PB (35 mg/kg/day subcutaneously) once daily exhibited a significant decrease in GFR and a notable increase in KIM-1 two hours after the first dose. Changes in GFR and KIM-1 at 24, 48 and 72 h were consistent and demonstrated the occurrence of kidney injury. Histopathological assessments showed a positive correlation between the severity of kidney injury and the changes in GFR and KIM-1 (Spearman’s rho = 0.3167, P = 0.0264). The other groups of mice injected with PB and PE did not show significant changes in GFR and AKI biomarkers compared to the control group.ConclusionThe group receiving PB (35 mg/kg/day subcutaneously) once daily consistently developed AKI at 2 h after the first dose. Establishing an early and stable AKI model facilitates researches into the mechanisms of early-stage kidney injury. In addition, our results indicated that PE had less toxicity than PB and mice receiving the same dose of PB in the QD group exhibited more severe kidney injury than the BID and TID groups.

Urinary Complement C3 and Vitamin D-Binding Protein Predict Adverse Outcomes in Patients with Acute Kidney Injury after Cardiac Surgery

Introduction: Acute kidney injury (AKI) is associated with adverse outcomes, including death and dialysis. The goal of this study was to identify prognostic biomarkers of AKI that could be used across multiple phenotypes of AKI and across different species. Methods: Liquid chromatography/tandem mass spectrometry analysis of urine samples from three species (human, rat, and mouse) and four etiologies of AKI identified five potential biomarkers, of which two were validated, complement C3 and vitamin D-binding protein, in a cohort of 157 patients that developed AKI following cardiothoracic surgery. We studied the relationship between the biomarker’s concentration in the urine and the development of a composite primary endpoint (stage 3 AKI within 10 days or death within 30 days). Results: Of the 153 patients who developed AKI following cardiovascular surgery, 17 met the combined primary outcome. The median concentration of urine complement C3 adjusted to urine creatinine had the best predictive value and was significantly higher in the primary outcome group than in the controls. Similarly, the median concentration of vitamin D-binding protein was higher in the primary outcome group. Conclusions: The studies provide proof in principle that cross-species discovery analyses could be a valuable tool for identifying novel prognostic biomarkers in AKI. Urine complement C3 and vitamin D-binding protein could be promising early predictors of adverse outcomes in patients who develop AKI after cardiac surgery.

CDKN1A promotes Cis-induced AKI by inducing cytoplasmic ROS production and ferroptosis

Background and objectiveThis study focuses on investigating the role of CDKN1A in cisplatin-induced AKI (acute kidney injury, AKI) and its potential as a biomarker for early diagnosis and therapeutic intervention by integrating bioinformatics analysis, machine learning, and experimental validation. MethodsWe analyzed the GSE85957 dataset to find genes that changed between control and cisplatin-treated rats. Using bioinformatics and machine learning, we found 13 important genes related to ferroptosis and the P53 pathway. The key gene, CDKN1A, was identified using various algorithms. We then tested how reducing CDKN1A in human kidney cells affected cell health, ROS, and iron levels. We also checked how CDKN1A changes the levels of proteins linked to ferroptosis using Q-PCR and Western Blot. ResultsCDKN1A was found to negatively regulate the G1/S phase transition and was associated with ferroptosis in p53 signaling. Experiments in human renal tubular epithelial cells (HK-2) and rat NRK-52E cells showed that CDKN1A knockdown mitigated cisplatin-induced cell injury by reducing oxidative stress and ferroptosis. ConclusionOur integrated approach identified CDKN1A as a biomarker for cisplatin-induced AKI. Its regulation could be key in AKI pathogenesis, offering new therapeutic insights and aiding in early diagnosis and intervention.

Senescence Biomarkers CKAP4 and PTX3 Stratify Severe Kidney Disease Patients.

Cellular senescence is the irreversible growth arrest subsequent to oncogenic mutations, DNA damage, or metabolic insult. Senescence is associated with ageing and chronic age associated diseases such as cardiovascular disease and diabetes. The involvement of cellular senescence in acute kidney injury (AKI) and chronic kidney disease (CKD) is not fully understood. However, recent studies suggest that such patients have a higher-than-normal level of cellular senescence and accelerated ageing. This study aimed to discover key biomarkers of senescence in AKI and CKD patients compared to other chronic ageing diseases in controls using OLINK proteomics. We show that senescence proteins CKAP4 (p-value < 0.0001) and PTX3 (p-value < 0.0001) are upregulated in AKI and CKD patients compared with controls with chronic diseases, suggesting the proteins may play a role in overall kidney disease development. CKAP4 was found to be differentially expressed in both AKI and CKD when compared to UHCs; hence, this biomarker could be a prognostic senescence biomarker of both AKI and CKD.

Маркеры нарушения почечной функции после перкутанной нефролитотрипсии.

Introduction. Kidney stones (KS) is a common disease and occupies a significant place in urological practice. The incidence of KS is actively growing in industrialized countries. Modern technologies make it possible to carry out mini-cut interventions, reducing the risks of complications of standard techniques. However, an increase in the duration of procedures can lead to perfusion-pressor complications and overheating of the irrigated fluid. Acute kidney injury (AKI) during intraoperative intervention worsens the prognosis of rehabilitation and affects the dynamics of morbidity. For reliable and timely diagnosis of renal dysfunction, research is being conducted to develop new AKI biomarkers. The aim of this study was to study the effect of various percutaneous access methods on the level of acute renal injury in patients with urolithiasis. Materials and methods. The study was conducted on the basis of the Center of Urology, Nephrology and Lithotripsy of the N. A. Semashko from 2022 to 2023. The results of surgical treatment of 21 patients with nephrolithiasis were studied. The patients were divided into two groups depending on the percutaneous access method: standard PNL (28 Ch) and mini-PNL (16 Ch). The work used modern biomarkers of renal damage, such as Cystatin C, NGAL, KIM-1 and IL-18 in the postoperative period. Results. An increase in the concentration of Cystatin C and NGAL after PNL prevailed in group 1, which is associated with the release of biomarkers by tubules from a larger area of damaged renal parenchyma. Changes in KIM-1 levels in the postoperative period were greater in group 2, which is associated with the greatest ischemic damage to renal tissue. A decrease in IL-18 levels in group 2 is associated with less damage to the renal tubules and the absence of inflammatory reactions. It was found out that after 48 hours all AKI biomarkers undergo regression. Conclusions. The results of the study showed that the level of renal damage was higher in patients who underwent standard PNL, compared with those who used mini-PNL. This indicates that the use of mini-PNL may reduce the risk of acute renal injury in patients with urolithiasis.

Comprehensive biomarker assessment for predicting severe acute kidney injury and need of kidney replacement therapy in liver transplantation patients

Background Renal dysfunction is a common complication following liver transplantation (LT). This study aimed to determine whether a comprehensive assessment of kidney function using nineteen serum and urinary biomarkers (BMs) within the first 48 h post-LT could enhance the prediction of severe acute kidney injury (AKI) and the need of kidney replacement therapy (KRT) during the first postoperative week. Methods Blood and urine (U) samples were collected during the pre- and postoperative periods. Nineteen BMs were evaluated to assess kidney health in the first 48 h after LT. Classification and regression tree (CART) cross-validation identified key predictors to determine the best BM combination for predicting outcomes. Results Among 100 LT patients, 36 developed severe AKI, and 34 required KRT within the first postoperative week. Preoperative assessment of U neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid-binding protein (L-FABP) predicted the need for KRT with 75% accuracy. The combined assessment of U osmolality (OSM), U kidney injury molecule 1 (KIM-1), and tissue inhibitor of metalloproteinase (TIMP-1) within 48 h post-LT predicted severe AKI with 80% accuracy. U-OSM alone, measured within 48 h post-LT, had an accuracy of 83% for predicting KRT need, outperforming any BM combination. Conclusions Combined BM analysis can accurately predict severe AKI and KRT needs in the perioperative period of LT. U-OSM alone proved to be an effective tool for monitoring the risk of severe AKI, available in most centers. Further studies are needed to assess its impact on AKI progression postoperatively. Registered at Clinical Trials (clinicaltrials.gov) in March 24th, 2014 by title ‘Acute Kidney Injury Biomarkers: Diagnosis and Application in Pre-operative Period of Liver Transplantation (AKIB)’ and identifier NCT02095431.

Early therapeutic drug monitoring of methotrexate and its association with acute kidney injury: A retrospective cohort study.

High-dose methotrexate (HDMTX) use can be limited by the development of acute kidney injury (AKI). Early AKI detection is paramount to prevent further renal injury and irreversible toxicities. This study sought to determine whether early elimination patterns of MTX would be useful as a biomarker of AKI in HDMTX treatment. This retrospective cohort study included two sites that collected ≥2 MTX levels within 16 h from completion of MTX infusion. Early levels were tagged and MTX elimination half-life (t½) were calculated from combinations of two of three different early time periods. Receiver operating characteristic (ROC) curves were synthesized for each elimination t½ (biomarker) with respect to AKI and delayed methotrexate elimination (DME); the biomarker with the highest area under the ROC curve (AUC) was tested in a multiple variable logistic regression model. Data from 169 patients who received a total of 556 courses of HDMTX were analyzed. ROC analysis revealed MTX elimination t½ calculated from the second and third time periods had the highest AUC for AKI at 0.62 (interquartile range [IQR] 0.56-0.69) and DME at 0.86 (IQR 0.73-1.00). After adjusting for age, sex, dose (mg/m2), infusion duration, HDMTX course, and baseline estimated glomerular filtration rate, it remained significant for AKI with an OR of 1.29 and 95% confidence interval of 1.03-1.65. Early MTX elimination t½ measured within 16 h of infusion completion was significantly associated with the development of AKI and serves as an early clearance biomarker that may identify patients who benefit from increased hydration, augmented leucovorin rescue, and glucarpidase administration.

P091 PROENKEPHALIN CONCENTRATION AND ITS DETERMINANTS IN PATIENTS WITH END-STAGE KIDNEY DISEASE TREATED WITH HEMODIALYSIS AND PERITONEAL DIALYSIS

Background and Objective. Proenkephalin (PENK) has been recently shown to reflect glomerular dysfunction and predict new-onset acute kidney injury and heart failure. While previous studies investigated PENK utility in individuals with preserved renal function, PENK concentration in patients with end-stage kidney disease (ESKD) remained to be established. The study aimed to assess plasma PENK concentration in patients with end-stage kidney disease (ESKD) treated with hemodialysis (HD) and peritoneal dialysis (PD) and to investigate its correlation with heart failure. Additionally, we aimed to determine whether PENK is removed during a hemodialysis session. Methods. 88 patients with ESKD (41 females) undergoing HD (n=66, 75%) and PD (n=22, 25%) were enrolled in this cross-sectional study. Blood samples for PENK determination were collected before and at the end of the hemodialysis session in HD patients and at a single time point in PD patients. Plasma proenkephalin concentration was assessed using a sandwich ELISA immunoassay. Samples for measurement of creatinine, urea, and NT-proBNP were drawn simultaneously. Results. The median (IQR) plasma PENK concentration in the overall population was 1.492 ng/ml (1.071-4.380). Both median eGFR (5 mL/min/1.73 m2 [4-7] vs. 5 mL/min/1.73 m2 [4-8], p=0,856) and plasma PENK levels (1.368 ng/ml [1.068-4.030] vs. 1.706 ng/ml [1.211-5.858], p=0.305) did not differ significantly between HD and PD patients. In HD patients, median PENK concentration was significantly higher before than after hemodialysis (1.368 vs. 2.061; p=0.003). No correlation was found between PENK level and urea (p=0.192), eGFR (p=0.922), duration of dialysis (p=0.637), and residual urine output (p=0.784). Heart failure (p=0.961), EF (p=0.361), and NT-proBNP (p=0.949) were not associated with increased PENK concentration. Conclusions. Our study proved that PENK is not removed during hemodialysis session. PENK concentration does not reflect renal function and cardiac status in patients with ESKD. The fact that PENK is not removed by hemodialysis calls into question the usefulness of PENK as an everyday use biomarker in acute kidney injury.

Nephrology rapid response team in the intensive care unit

Acute kidney injury (AKI) is a frequent complication in patients admitted to the intensive care unit (ICU), and it is known as an independent factor for adverse outcomes like increased length of hospital stay, the development of chronic kidney disease (CKD), and increased mortality with the associated high cost to healthcare systems. The use of AKI biomarkers and new tools such as point-of-care ultrasonography (POCUS) to perform a hemodynamic and volume status assessment has made it more feasible to detect or predict kidney damage in a very accurate way, thereby avoiding the progression of AKI. The design and implementation of a nephrology rapid response team (NRRT) should be considered to improve patient outcomes and healthcare costs. In this paper, we provide an overview of the implementation of an NRRT.

Aminopeptidasic Enzymes as Early Biomarkers of Cardiac Surgery-Associated Acute Kidney Injury and Long-Term Events.

Diagnosis of acute kidney injury (AKI) relies on serum creatinine (SCr) changes. This study investigated if urinary aminopeptidases are early and predictive biomarkers of cardiac surgery-associated AKI (CSA-AKI). Glutamyl aminopeptidase (GluAp), alanyl aminopeptidase (AlaAp), dipeptidyl peptidase-4 (DPP4), proteinuria, albuminuria, N-acetyl-β-D-glucosaminidase (NAG), and neutrophile gelatinase-associated lipocalin (NGAL) were measured in urine samples from 44 patients at arrival in the intensive care unit (ICU) after cardiac surgery. Sensitivity, specificity, and positive and negative predictive value for diagnosis of stages 1, 2, and 3 of AKI were analyzed for the highest quartile of each marker. We also studied the relationship with SCr after surgery, 6- and 12-month glomerular filtration rates (GFRs), and other long-term events over the next 5 years. GluAp diagnosed the maximal number of patients that developed stage 2 or 3 of AKI, increasing diagnostic sensitivity from 0% to 75%. In addition, GluAp and DPP4 were related to the decrease in GFR at 6 or 12 months after surgery. Urinary aminopeptidases are a potential tool for the early diagnosis of CSA-AKI, with GluAp being the most effective marker for diagnosing stage 2 or 3 of AKI at ICU admission. GluAp and DPP4 serve as predictive biomarkers for a decrease in GFR.