Neutrophil gelatinase-associated lipocalin as the real-time indicator of active kidney damage

Clinical Impacts of Urinary Neutrophil Gelatinase-Associated Lipocalin in Patients With Chronic Kidney Disease Undergoing Percutaneous Coronary Intervention

BACKGROUND

Chronic kidney disease (CKD) is associated with poor prognosis in patients undergoing percutaneous coronary intervention (PCI). Urinary neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for renal injury. However, the association between urinary NGAL concentrations and renal and cardiovascular events in patients with CKD undergoing PCI has not been elucidated. This study investigated the clinical impact of urinary NGAL concentrations on renal and cardiovascular outcomes in patients with non-dialysis CKD undergoing PCI.Methods and Results: We enrolled 124 patients with non-dialysis CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) undergoing elective PCI. Patients were divided into low and high NGAL groups based on the median urinary NGAL concentration measured the day before PCI. Patients were monitored for renal and cardiovascular events during the 2-year follow-up period. Kaplan-Meier analyses showed that the incidence of renal and cardiovascular events was higher in the high than low NGAL group (log-rank P<0.001 and P=0.032, respectively). Multivariate Cox proportional hazards analyses revealed that urinary NGAL was an independent risk factor for renal (hazard ratio [HR] 4.790; 95% confidence interval [CI] 1.537-14.924; P=0.007) and cardiovascular (HR 2.938; 95% CI 1.034-8.347; P=0.043) events.

CONCLUSIONS

Urinary NGAL could be a novel and informative biomarker for predicting subsequent renal and cardiovascular events in patients with CKD undergoing elective PCI.

Urinary Epidermal Growth Factor Level as a Noninvasive Indicator of Tubular Repair in Patients with Acute Kidney Injury

Epidermal growth factor (EGF), an essential factor for the proliferation and survival of renal tubular cells, is expressed by distal tubules and normally excreted via urine. Previous studies in rats demonstrated that acute tubular injury reduces urinary EGF levels. However, it is unclear whether urinary EGF is a suitable monitoring marker of tubular repair status after acute kidney injury (AKI) in humans. To address this question, we measured serum and urinary EGF in patients with AKI (n = 99) using ELISA and investigated whether urinary EGF levels were associated with the severity of tubular injury and renal prognosis. Urinary EGF was abundant in healthy controls but showed a significant decrease in AKI patients (14,522 ± 2190 pg/mL vs. 3201 ± 459.7 pg/mL, p < 0.05). The urinary EGF level in patients with renal AKI was notably lower than that in patients with pre-renal AKI. Furthermore, the urinary EGF level in patients with AKI stage 3 was significantly lower than that in patients with AKI stage 1. Urinary EGF levels were negatively correlated with urinary β-2MG and serum creatinine levels but positively correlated with hemoglobin levels and eGFR. Urinary EGF was not significantly correlated with urinary NAG, α-1MG, L-FABP, NGAL, KIM-1, or urinary protein concentrations. No significant correlation was observed between serum and urinary EGF levels, suggesting that urinary EGF is derived from the renal tubules rather than the blood. In living renal transplantation donors, the urinary EGF/Cr ratio was approximately half the preoperative urinary EGF/Cr ratio after unilateral nephrectomy. Collectively, these data suggest that urinary EGF is a suitable noninvasive indicator of not only the volume of functional normal renal tubules but also the status of tubular repair after AKI.

Hepatorenal Syndrome-Novel Insights into Diagnostics and Treatment

Hepatorenal syndrome (HRS) is a disorder associated with cirrhosis and renal impairment, with portal hypertension as its major underlying cause. Moreover, HRS is the third most common cause of acute kidney injury, thus creating a major public health concern. This review summarizes the available information on the pathophysiological implications of HRS. We discuss pathogenesis associated with HRS. Mechanisms such as dysfunction of the circulatory system, bacterial infection, inflammation, impaired renal autoregulation, circulatory, and others, which have been identified as critical pathways for development of HRS, have become easier to diagnose in recent years. Additionally, relatively recently, renal dysfunction biomarkers have been found indicating renal injury, which are involved in the pathophysiology of HRS. This review also summarizes the available information on the management of HRS, focusing on vasoconstrictive drugs, renal replacement therapy, and liver transplant together with currently being investigated novel therapies. Analyzing new discoveries for the underlying causes of this condition assists the general research to improve understanding of the mechanism of pathophysiology and thus prevention of HRS.

An analysis of the relationship between donor and recipient biomarkers and kidney graft function, dysfunction, and rejection

BACKGROUND

The study aimed to find predictive biomarkers to evaluate donor kidney function to predict graft dysfunction as well as to assess an early signs of acute graft rejection.

METHOD

Twenty-seven deceased donors and 54 recipients who underwent a successful kidney transplantation were enrolled in the study. An assessment was made in serum and urine from donors and recipients to measure the following biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), tissue inhibitor of metalloproteinase 2 (TIMP-2) and urinary N-acetyl-b-D-glucosaminidase (uNAG). These biomarkers were used to establish a model for predicting a reduced graft function (RGF) classified as either a delayed or slow graft function.

RESULT

Our analysis suggest that out of four tested biomarkers, the serum TIMP-2 and uNAG levels of the donors had a predictive value for RGF; the area under the receiver operating characteristic curves (AUROC) of serum TIMP-2 and uNAG were 0.714 and 0.779, respectively. The combined best fitting prediction model of serum TIMP-2, uNAG, and creatinine levels was better in predicting RGF than the serum creatinine level alone. In addition, the recipient serum TIMP-2 level on the third day post-transplantation (D3) was associated with the estimated glomerular filtration rate (eGFR) on the seventh day post-transplantation (D7; OR 1.119, 95% CI 1.016-1.233, p = 0.022). Furthermore, the ROC curve value revealed that the AUROC of TIMP-2 on D3 was 0.99 (95% CI 0.97-1, p < 0.001), and this was the best predictive value of the renal function on D7.

CONCLUSIONS

Donor serum TIMP-2 and uNAG levels are useful predictive biomarkers because they can provide the donor-based prediction for RGF.

Biotherapy of experimental acute kidney injury: emerging novel therapeutic strategies

Acute kidney injury (AKI) is a complex and heterogeneous disease with high incidence and mortality, posing a serious threat to human life and health. Usually, in clinical practice, AKI is caused by crush injury, nephrotoxin exposure, ischemia-reperfusion injury, or sepsis. Therefore, most AKI models for pharmacological experimentation are based on this. The current research promises to develop new biological therapies, including antibody therapy, non-antibody protein therapy, cell therapy, and RNA therapy, that could help mitigate the development of AKI. These approaches can promote renal repair and improve systemic hemodynamics after renal injury by reducing oxidative stress, inflammatory response, organelles damage, and cell death, or activating cytoprotective mechanisms. However, no candidate drugs for AKI prevention or treatment have been successfully translated from bench to bedside. This article summarizes the latest progress in AKI biotherapy, focusing on potential clinical targets and novel treatment strategies that merit further investigation in future pre-clinical and clinical studies.

The Urinary Concentrations of Neutrophil Gelatinase-Associated Lipocalin, Cystatin C and Osteopontin in the Healthy Term and Stable Preterm Neonates: A Pilot Study

BACKGROUND

In neonates, the assessment of kidney function with serum creatinine is limited; therefore, more effective biomarkers are needed.

AIM

The study aimed at analyzing the concentrations of renal biomarkers (osteopontin, cystatin C, and NGAL) in neonates.

MATERIAL AND METHODS

The study included 80 term and 20 preterm neonates aged 28-33 weeks of gestation. Biomarkers were measured in urine. Term neonates' urine was collected on the 1st day of life. Preterm neonates' urine was collected on the 1st, 8th, 15th, 22nd day of life. Biomarkers' concentrations were normalized to urinary creatinine (cr.) and presented as urinary biomarker/cr. ratios.

RESULTS

Median values of biomarker/creatine ratios in term and preterm neonates were the following: cystatin C/cr.: 7.26 and 439.49; osteopontin/cr.: 135.86 and 1633.37; NGAL/cr. in girls: 212.14 and 256.93; and NGAL/cr. in boys 27.123 and 65.29 ng/mg cr. In preterm neonates the cystatin C/cr. ratio was higher on the 1st than on the 8th day. The osteopontin/cr. ratio did not differ between the days. The NGAL/cr. ratio in girls was higher on the 8th than on the 22nd day, and in boys, the lowest was on the 22nd day.

CONCLUSIONS

Prematurity in stable, Caucasian neonates might cause higher osteopontin and cystatin C excretion, but not NGAL. The excretion of NGAL and cystatin C, but not osteopontin, may change during first weeks of premature neonate's life.

Urinary Neutrophil Gelatinase-associated Lipocalin as a Diagnostic and Prognostic Marker for Acute Kidney Injury in Hospitalized Cirrhotic Patients: A Study from North Indian Population

Background

A serious problem in cirrhosis is acute renal injury. The study aimed to examine the urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a diagnostic and prognostic marker of acute kidney injury (AKI) in cirrhotic patients.

Methods

A prospective study was carried out over a period of 1 year. A total of 490 patients suffering from cirrhosis who visited an indoor hospital were screened, and after the exclusion, a total of 90 subjects admitted to the medicine intensive care unit (MICU) fulfilling inclusion criteria were enrolled. Those having a history of renal diseases, on nephrotoxic drugs, in septic shock, peritonitis, UTI, and no urine output were excluded. On admission, for the estimation of uNGAL, urinary levels of sodium, creatinine, fresh urine samples were obtained, and blood samples were taken for serum creatinine estimation.

Results

Out of 90 patients, 33.3% did not develop AKI, and 66.7% developed AKI. Urinary neutrophil gelatinase-associated lipocalin levels were six times higher in patients with acute tubular necrosis (259.08 ± 118.41 ng/mL) and three times higher in Hepatorenal syndrome (HRS)-AKI (124.97 ± 16.38) as compared with patients with normal kidney function (39.76 + 5.7). Those who died had a higher uNGAL (171.6 ng/mL) in comparison to those who survived (133.7 ng/mL). At a cutoff value of ≥114.9 (ng/mL), urinary NGAL represents a sensitivity of 86.92% and specificity of 100% to diagnose AKI and AUC 0.966 (95% CI: 0.919-0.990) in cirrhotic patients.

Conclusion

Urinary NGAL is good for diagnosing AKI and is a marker to distinguish the types of AKI in liver cirrhosis.

How to cite this article

Patel ML, Shyam R, Chaudhary A, Sachan R, Ali W. Urinary Neutrophil Gelatinase-associated Lipocalin as a Diagnostic and Prognostic Marker for Acute Kidney Injury in Hospitalized Cirrhotic Patients: A Study from North Indian Population. Indian J Crit Care Med 2023;27(8):545-551.

Preoperative and postoperative urinary NGAL levels in children with bladder exstrophy

BACKGROUND

Urinary NGAL (neutrophil gelatinase-associated lipocalin) levels have been shown to predict renal damage in various medical conditions. The present study was conducted to study the role of urinary NGAL levels in children with bladder exstrophy-epispadias complex post single-stage total reconstruction (SSTR) as markers of early renal function reduction.

METHODS

Urine samples were collected from children with bladder exstrophy before SSTR (Group A, n = 11), 5 years post SSTR (Group B, n = 40) and controls (Group C, n = 41) and stored at - 20 °C. NGAL levels were estimated using double antibody sandwich ELISA.

RESULTS

Mean NGAL levels in Groups A, B and C were 1.39, 34.24 and 2.58 ng/ml, respectively. Mean NGAL levels among Group B subjects with glomerular filtration rate (GFR) ≥ 80 ml/min/1.73 m2 body surface area (BSA) was 29.8 ng/ml, while it was 31.74 ng/ml in those with GFR < 80 ml/min. Urine samples were also evaluated 6 months post SSTR. Mean NGAL at 6 months was 6.76 ng/ml, while at 12 months it was 30.3 ng/ml, remaining > 30 ng/ml at 18 and 24 months. Dimercaptosuccinic acid (DMSA) scans did not show any scarring, and GFR on diethylenetriamine pentaacetate (DTPA) scans remained stable.

CONCLUSIONS

Increasing levels of urinary NGAL following bladder-exstrophy and epispadias complex repair suggest that NGAL detects the earliest signs of renal damage even before any deterioration is observed in DMSA and/or DTPA-GFR scans. Further studies with an adequate sample size and periodic measurement of NGAL need to be performed before any definitive conclusion can be drawn.

The Role of Urinary NGAL in the Management of Primary Vesicoureteral Reflux in Children

Vesicoureteral reflux (VUR) is the most frequent congenital urinary tract malformation and an important risk factor for urinary tract infections (UTIs). Up to 50% of children with VUR may develop reflux nephropathy (RN), and the diagnosis and monitoring of renal scars are invasive and costly procedures, so it is paramount to find a non-invasive and accurate method to predict the risk of renal damage. Neutrophil gelatinase-associated lipocalin (NGAL) has already proven to be a good predictive biomarker in acute kidney injuries, but there are few studies that have investigated the role of NGAL in primary VUR in children. Our aim is to review the predictive value of urine NGAL (uNGAL) as a non-invasive biomarker of RN in children with primary VUR, as well as its ability to predict the evolution of chronic kidney disease (CKD). Based on our analysis of the available original studies, uNGAL can be an accurate and reliable biomarker of RN and its progression to CKD. Some studies suggested a good correlation between VUR severity and uNGAL levels, but other studies found no significant correlation. The relationship between VUR severity and uNGAL levels is likely complex and influenced by factors such as UTIs, the timing of the urine sample collection, and the age and overall health of the patient.

Untargeted plasma 1H NMR-based metabolomic profiling in different stages of chronic kidney disease

Chronic kidney disease (CKD) is a serious public health issue affecting thousands of people worldwide. CKD diagnosis is usually made by Estimated Glomerular Filtration Rate (eGFR) and albuminuria, which limit the knowledge of the mechanisms behind CKD progression. The aim of the present study was to identify changes in the metabolomic profile that occur as CKD advances. In this sense, 77 plasma samples from patients with CDK were evaluated by 1D and 2D Nuclear Magnetic Resonance Spectroscopy (NMR). The NMR data showed significant changes in the metabolomic profile of CKD patients and the control group. Principal component analysis (PCA) clustered CKD and control patients into three distinct groups, control, stage 1 (G1)-stage 4 (G4) and stage 5 (G5). Lactate, glucose, acetate and creatinine were responsible for discriminating the control group from all the others CKD stages. Valine, alanine, glucose, creatinine, glutamate and lactate were responsible for the clustering of G1-G4 stages. G5 was discriminated by calcium ethylenediamine tetraacetic acid, magnesium ethylenediamine tetraacetic acid, creatinine, betaine/choline/trimethylamine N-oxide (TMAO), lactate and acetate. CKD G5 plasma pool which was submitted in MetaboAnalyst 4.0 platform (MetPA) analysis and showed 13 metabolic pathways involved in CKD physiopathology. Metabolic changes associated with glycolysis and gluconeogenesis allowed discriminating between CKD and control patients. The determination of involved molecules in TMAO generation in G5 suggests an important role in this uremic toxin linked to CKD and cardiovascular diseases. The aforementioned results propose the feasibility of metabolic assessment of CKD by NMR during treatment and disease progression.

Disseminated intravascular coagulation phenotype is regulated by the TRPM7 channel during sepsis

BACKGROUND

Sepsis is an uncontrolled inflammatory response against a systemic infection that results in elevated mortality, mainly induced by bacterial products known as endotoxins, producing endotoxemia. Disseminated intravascular coagulation (DIC) is frequently observed in septic patients and is associated with organ failure and death. Sepsis activates endothelial cells (ECs), promoting a prothrombotic phenotype contributing to DIC. Ion channel-mediated calcium permeability participates in coagulation. The transient reception potential melastatin 7 (TRPM7) non-selective divalent cation channel that also contains an α-kinase domain, which is permeable to divalent cations including Ca²⁺, regulates endotoxin-stimulated calcium permeability in ECs and is associated with increased mortality in septic patients. However, whether endothelial TRPM7 mediates endotoxemia-induced coagulation is not known. Therefore, our aim was to examine if TRPM7 mediates coagulation during endotoxemia.

RESULTS

The results showed that TRPM7 regulated endotoxin-induced platelet and neutrophil adhesion to ECs, dependent on the TRPM7 ion channel activity and by the α-kinase function. Endotoxic animals showed that TRPM7 mediated neutrophil rolling on blood vessels and intravascular coagulation. TRPM7 mediated the increased expression of the adhesion proteins, von Willebrand factor (vWF), intercellular adhesion molecule 1 (ICAM-1), and P-selectin, which were also mediated by the TRPM7 α-kinase function. Notably, endotoxin-induced expression of vWF, ICAM-1 and P-selectin were required for endotoxin-induced platelet and neutrophil adhesion to ECs. Endotoxemic rats showed increased endothelial TRPM7 expression associated with a procoagulant phenotype, liver and kidney dysfunction, increased death events and an increased relative risk of death. Interestingly, circulating ECs (CECs) from septic shock patients (SSPs) showed increased TRPM7 expression associated with increased DIC scores and decreased survival times. Additionally, SSPs with a high expression of TRPM7 in CECs showed increased mortality and relative risk of death. Notably, CECs from SSPs showed significant results from the AUROC analyses for predicting mortality in SSPs that were better than the Acute Physiology and Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores.

CONCLUSIONS

Our study demonstrates that sepsis-induced DIC is mediated by TRPM7 in ECs. TRPM7 ion channel activity and α-kinase function are required by DIC-mediated sepsis-induced organ dysfunction and its expression are associated with increased mortality during sepsis. TRPM7 appears as a new prognostic biomarker to predict mortality associated to DIC in SSPs, and as a novel target for drug development against DIC during infectious inflammatory diseases.

Procoagulant phenotype induced by oxidized high-density lipoprotein associates with acute kidney injury and death

BACKGROUND

Oxidative stress derived from severe systemic inflammation promotes conversion from high-density lipoprotein HDL to oxidized HDL (oxHDL), which interacts with vascular endothelial cells (ECs). OxHDL acquires procoagulant features playing a role in modulating coagulation, which has been linked with organ failure in ICU patients. However, whether oxHDL elicits a ECs-mediated procoagulant phenotype generating organ failure and death, and the underlying molecular mechanism is not known. Therefore, we studied whether oxHDL-treated rats and high-oxHDL ICU patients exhibit a procoagulant phenotype and its association with kidney injury and mortality and the endothelial underlying molecular mechanism.

METHODS

Human ECs, oxHDL-treated rats and ICU patients were subjected to several cellular and molecular studies, coagulation analyses, kidney injury assessment and mortality determination.

RESULTS

OxHDL-treated ECs showed a procoagulant protein expression reprograming characterized by increased E-/P-selectin and vWF mRNA expression through specific signaling pathways. OxHDL-treated rats exhibited a procoagulant phenotype and modified E-/P-selectin, vWF, TF and t-PA mRNA expression correlating with plasma TF, t-PA and D-dimer. Also, showed increased death events and the relative risk of death, and increased creatinine, urea, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased eGFR, all concordant with kidney injury, correlated with plasma TF, t-PA and D-dimer. ICU patients showed correlation between plasma oxHDL and increased creatinine, cystatin, BUN, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased GFR. Notably, ICU high-oxHDL patients showed decreased survival. Interestingly, altered coagulation factors TF, t-PA and D-dimer correlated with both increased oxHDL levels and kidney injury markers, indicating a connection between these factors.

CONCLUSION

Increased circulating oxHDL generates an endothelial-dependent procoagulant phenotype that associates with acute kidney injury and increased risk of death.

Concentrations and kinetics of renal biomarkers in dogs with gastric dilatation-volvulus with and without 24-h intravenous lidocaine

Background

Gastric dilatation volvulus (GDV) can lead to organ failure including acute kidney injury (AKI). Due to its cytoprotective, antioxidant and anti-inflammatory effects, lidocaine has a potential to prevent AKI in dogs with GDV.

Design and setting

Prospective, observational cohort study in client-owned dogs with GDV.

Objective

To determine concentrations of renal biomarkers for AKI in dogs with GDV with and without intravenous (IV) lidocaine therapy.

Methods

Thirty-two dogs were randomized to receive either IV lidocaine (2 mg/kg, followed by a lidocaine constant rate infusion at a dose of 50 μg/kg/min over 24 h; n = 17) or no lidocaine (n = 15). Blood and urine samples were taken at admission (T 0) (only blood), during or immediately after surgery (T 1), and 24 (T 24) and 48 (T 48) h after surgery. Plasma creatinine (pCr), plasma neutrophil gelatinase-associated lipocalin (pNGAL), urinary NGAL (uNGAL), uNGAL to creatinine ratio (UNCR), and urinary gamma-glutamyl transferase to creatinine ratio (uGGT/uCr) were evaluated. Biomarker concentrations were compared between dogs with and without IV lidocaine and the course of each marker was determined in comparison to its admission value.

Results

In the entire population, a significantly higher pCr at T 0 (median, 95 μmol/L, interquartile range, 82-105) compared with T 1 (69 μmol/L, 60-78), T 24 (63 μmol/L, 52-78), and T 48 (78 μmol/L, 65-87) (P < 0.001) was found. Plasma NGAL increased significantly between T 0 (5.66 ng/mL, 3.58-7.43) and T 24 (7.50 ng/mL, 4.01-11.89) (P = 0.006) and T 48 (9.86 ng/mL, 5.52-13.92) (P < 0.001), respectively. Urinary NGAL increased significantly between T 1 (0.61 ng/mL, 0.30-2.59) and T 24 (2.62 ng/mL, 1.86-10.92) (P = 0.001) and T 48 (4.79 ng/mL, 1.96-34.97 (P < 0.001), respectively. UNCR increased significantly between T 1 (0.15 μg/mmol, 0.09-0.54) and T 24 (1.14 μg/mmol, 0.41-3.58) (P = 0.0015) and T 48 (1.34 μg/mmol, 0.30-7.42) (P < 0.001), respectively. Concentrations of uGGT/uCr increased significantly from T 0 highest at T 24 (6.20 U/mmol, 3.90-9.90) and significantly decreased at T 48 (3.76 U/mmol, 2.84-6.22) (P < 0.001). No significant differences in any renal biomarker concentration were found between dogs with and without IV lidocaine therapy.

Conclusion and clinical relevance

Plasma NGAL, uNGAL and UNCR remained increased up to 48 h post-surgery. No evidence of lidocaine-associated renoprotection was found.

Plasma Neutrophil Gelatinase-Associated Lipocalin Associates with New-Onset Chronic Kidney Disease in the General Population

Circulating levels of neutrophil gelatinase-associated lipocalin (NGAL) have been associated with acute kidney injury and the severity and progression of chronic kidney disease (CKD). This study investigated its potential utility as a biomarker for the risk of new-onset CKD in a population-based cohort study. Individuals without CKD at baseline (n = 4660) who participated in the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) prospective population-based cohort study in the Netherlands were included. Baseline plasma NGAL concentrations were investigated for their associations with new-onset CKD, defined as a composite outcome of an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m², urinary albumin excretion (UAE) > 30 mg/24-h, or both. Mean (±SD) plasma NGAL concentrations were 104.0 (±34.7) μg/L and median eGFR was 96 [IQR: 85.3-105.8] mL/min/1.73 m². After median follow-up of 8.3 [IQR: 7.8-8.9] years, 467 participants developed new-onset CKD. Plasma NGAL concentrations were significantly associated with an increased risk of new-onset CKD (hazard ratio [HR] per doubling 1.35 [95% CI: 1.11-1.63], p = 0.002), even after adjustment for potentially confounding factors (1.37 [1.09-1.73], p = 0.007) except baseline eGFR (1.09 [0.86-1.37], p = 0.490). In secondary analyses, plasma NGAL concentrations were significantly associated with new-onset CKD as defined by eGFR < 60 mL/min/1.73 m² alone (adjusted HR per doubling 2.54 [1.69-3.80], p < 0.001), which was abrogated after adjustment for eGFR (1.05 [0.69-1.59], p = 0.828), also when UAE > 30 mg/24-h was set as individual outcome (1.05 [0.82-1.35], p = 0.705). Higher plasma NGAL concentrations are associated with an increased risk of developing CKD in the general population. This association is dependent on renal function, and mainly driven by new-onset CKD as defined by renal function decline.

Short-term intra-individual variation of urinary biomarkers in dogs with stable chronic kidney disease

BACKGROUND

Active-ongoing kidney damage is present in animals with stable chronic kidney disease (CKD), as reflected by biomarkers in urine. Interpretation of serial messurements of biomarkers requires knowledge of its intra-individual variation.

AIMS

To evaluate the short-term intra-individual variation of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 (uNGAL, uKIM-1, respectively) in dogs with stable CKD, and to determine whether normalization to urinary creatinine (uCr) decreases variation.

ANIMALS

Twenty-five dogs with naturally-occurring stable CKD.

METHODS

Prospective, observational study. Dogs were diagnosed with CKD based on the International Renal Interest Society guidelines. Dogs were included only if the variation in serum creatinine concentration was <25% on at least 2 measurements during the 3 months preceding inclusion, and only if serum creatinine variation was <20% during the 14-day study period. Urine samples were collected on days 0, 4, 10 and 14. uNGAL and uKIM-1 were measured using ELISA.

RESULTS

The median coefficients of variation (CV) of uNGAL and uNGAL/uCr were 42% (range, 7%-127%), and 44% (range, 8%-100%), respectively, and the CV 90th percentiles were 97% and 83%, respectively. The median CV of uKIM-1 and uKIM-1/uCr were 29% (range, 16%-91%), and 23% (range, 6%-76%), respectively, and the CV 90th percentiles were 56% and 52%, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Changes of >100% and >60% for uNGAL and uKIM-1, respectively, in serial measurements are higher than the normal expected variation and therefore might indicate need for further investigation for underlying causes of kidney damage.

Predictive markers in chronic kidney disease

Chronic kidney disease (CKD) is defined by gradual deterioration of the renal parenchyma and decline of functioning nephrons. CKD is now recognized as a distinct risk factor for cardiovascular disease (CVD). This risk rises in tandem with the decline in kidney function and peaks at the end-stage. It is important to identify individuals with CKD who are at a higher risk of advancing to end-stage renal disease (ESRD) and the beginning of CVD. This will enhance the clinical benefits and so that evidence-based therapy may be started at the initial stages for those individuals. A promising biomarker must represent tissue damage, and be easy to detect using non-invasive methods. Current CKD progression indicators have difficulties in reaching this aim. Hence this review presents an update on markers studied in the last decade, which help in the prediction of CKD progression such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, urinary liver-type fatty acid-binding protein, cystatin-C, asymmetric dimethylarginine, symmetric dimethylarginine, endotrophin, methylglyoxal, sclerostin, uric acid, and miRNA-196a. Additional research is needed to determine the predictive usefulness of these indicators in clinical samples for disease development. Their utility as surrogate markers need to be explored further for the early identification of CKD progression.

Electrochemical detection of acute renal disease biomarker by Galinstan nanoparticles interfaced to bilayer polymeric structured dirhenium heptoxide film

This work describes a facile fabrication of an efficient electrochemical sensor utilizing sonication-derived Galinstan nanoparticles (Galinstan NPs) interfaced to annealed dirhenium heptoxide (Re₂O₇) thin-film on Silicon (Si) for the quantitative detection of the most promising acute renal disease biomarker Neutrophil Gelatinase Associated Lipocalin (NGAL). Under optimized preconditions, the anti-NGAL antibodies were immobilized on the Galinstan NPs/Re₂O₇/Si electrode by carbodiimide crosslinking to detect NGAL. The composition, morphology, and structural properties of the electrode were elucidated by various physical characterizations. The sensor obtained a high sensitivity (0.018 µA^-1ng^-1ml^-1, R² = 0.99) in differential pulse voltammetry and a minimum detection limit (2.14 ng ml^-1) in electrochemical impedance spectroscopy for a wide range of NGAL concentrations (25-650 ng ml^-1) with high selectivity and stability. The intensified performance of the sensor was achieved by the summed-up electron transfer from the Re₂O₇ film to Galinstan NPs and Galinstan NPs to the electroactive reactants. Additionally, the outer 2D gallium oxide (Ga₂O₃) layer of Galinstan Nps enhanced the redox activities, whereas the metallic core contributed to the magnificent conductivity. The excellent recovery rates of the sensor for different concentrations of NGAL measured in commercial human serum by the standard addition method assured the feasibility of the sensor.

Exosomes Derived from BM-MSCs Mitigate the Development of Chronic Kidney Damage Post-Menopause via Interfering with Fibrosis and Apoptosis

The rate of chronic kidney disease (CKD) is increasing globally, and it is caused by continuous damage to kidney tissue. With time the renal damage becomes irreversible, leading to CKD development. In females, post-menopause lack of estrogen supply has been described as a risk factor for CKD development, and studies targeting post-menopause CKD are scarce. In the present study, we used exosomes isolated from bone marrow mesenchymal stem/stromal cells (BM-MSCs) to test their therapeutic potential against the development of CKD. At first, the menopause model was achieved by surgical bilateral ovariectomy in female albino rats. After that, 100 µg of exosomes was given to ovariectomized rats, and the study continued for 2 months. Changes in urine volume, urine protein content, kidney function biochemical parameters (creatinine and BUN), kidney antioxidant parameters (SOD, GPx and CAT), histological changes, immunohistochemical levels of caspase 3, and the gene expression of NGAL (related to kidney damage), TGFβ1 and αSMA (related to fibrosis and EMT), and caspase 3 (related to apoptosis) were studied. After the ovariectomy, the occurrence of CKD was confirmed in the rats by the drastic reduction of serum estrogen and progesterone levels, reduced urine output, increased urinary protein excretion, elevated serum creatinine and BUN, reduced GPx SOD, and CAT in kidney tissue, degenerative and fibrotic lesions in the histopathological examination, higher immunohistochemical expression of caspase 3 and increased expression of all studied genes. After exosomes administration, the entire chronic inflammatory picture in the kidney was corrected, and a near-normal kidney structure and function were attained. This study shows for the first time that BM-MSCs exosomes are potent for reducing apoptosis and fibrosis levels and, thus, can reduce the chronic damage of the kidneys in females that are in their menopause period. Therefore, MSCs-derived exosomes should be considered a valuable therapy for preserving postmenopausal kidney structure and function and, subsequently, could improve the quality of females’ life during menopause.

Discovery of preventive drugs for cisplatin-induced acute kidney injury using big data analysis

Cisplatin is effective against many types of carcinoma. However, a high rate of renal damage is a clinical problem. Thus, there is a need to establish a method to prevent it. Although various compounds have been reported to be effective against cisplatin-induced renal injury, there are no examples of their clinical application. Therefore, we attempted to search for prophylactic agents with a high potential for clinical application. We used Cascade Eye to identify genes that are altered during cisplatin-induced renal injury, Library of Integrated Network-based Cellular Signatures (LINCS) to identify drugs that inhibit changes in gene expression, and a large database of spontaneous adverse drug reaction reports to identify drugs that could prevent cisplatin-induced kidney injury in clinical practice. In total, 10 candidate drugs were identified. Using the US FDA Adverse Event Reporting System (FAERS), we identified drugs that reduce cisplatin-induced kidney injury. Fenofibrate was selected as a candidate drug to prevent cisplatin-induced kidney injury based on the FAERS analysis. A model was used to evaluate the efficacy of fenofibrate against cisplatin-induced renal injury. Studies using HK2 cells and mouse models showed that fenofibrate significantly inhibited cisplatin-induced renal injury but did not inhibit the antitumor effect of cisplatin. Fenofibrate is a candidate prophylactic drug with high clinical applicability for cisplatin-induced renal injury. Analysis of data from multiple big databases will improve the search for novel prophylactic drugs with high clinical applicability. For the practical application of these findings, evaluation in prospective controlled trials is necessary.

Utility of plasma NGAL for the diagnosis of AKI following cardiac surgery requiring cardiopulmonary bypass: a systematic review and meta-analysis

The objective of this study was to assess the diagnostic value of plasma neutrophil gelatinase-associated lipocalin (pNGAL) for the early diagnosis of acute kidney injury (AKI) in adult patients following cardiac surgery requiring cardiopulmonary bypass (CPB). Electronic databases and other resources were systematically searched for relevant studies. Risk of bias was assessed using the Quality Assessment for Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Studies were assigned to a sub-group based on the timing of the pNGAL sample in relation to the cessation of CPB. These were < 4 h, 4–8 h, 12 h or 24 h post-cessation of CPB. Summary values for sensitivity and specificity were estimated using the hierarchical summary receiver operator characteristic (ROC) curve model. A random-effects meta-analysis of each pair of sensitivity and specificity estimates from each included study was performed. In total, 3131 patients from 16 studies were included. When taken at 4–8 h following CPB, pNGAL had superior performance for the diagnosis of AKI in the defined population when compared to earlier and later time points. Prediction regions and confidence intervals, however, demonstrated significant variability in pooled estimates of sensitivity and specificity. This is likely due to population and study design heterogeneity, lack of standardisation of assays and thresholds, and inability to distinguish the different molecular forms of NGAL. In conclusion, the diagnostic utility of pNGAL in this clinical setting is inconclusive and large individual studies of representative populations of cardiac surgery patients using assays that specifically detect NGAL in its monomeric form are required.

Predictive Value of Elevated Neutrophil Gelatinase-Associated Lipocalin (NGAL) Levels for Assessment of Cardio-Renal Interactions among ST-Segment Elevation Myocardial Infarction Patients

Background: Elevated serum neutrophil gelatinase-associated lipocalin (NGAL) levels reflect both inflammatory reactions and renal tubular injury. Recently, associations with endothelial dysfunction and plaque instability were also proposed. We investigated the prognostic utility of elevated NGAL levels for renal and clinical outcomes among ST-segment elevation myocardial infarction (STEMI) patients treated with primary coronary intervention (PCI). Methods: We performed a prospective, observational, open-label trial. High NGAL was defined as values within the third tertile (>66 percentile). Results: A total of 267 patients were included (mean age 66 ± 14 years, 81% males). Short-term adverse outcomes were consistently increased in the high NGAL group with more acute kidney injury, lower mean left ventricular ejection fraction, higher 30-day mortality, and higher incidence for the composite outcome of major adverse cardiac events (MACE). In a multivariate logistic regression model, high NGAL emerged as a strong and independent predictor for MACE (OR 2.07, 95% CI 1.15−3.73, p = 0.014). Conclusions: Among STEMI patients undergoing primary PCI, elevated NGAL levels are associated with adverse renal and cardiovascular outcomes, independent of traditional inflammatory markers. Further studies are needed to assess the potentially unique role of NGAL in cardio−renal interactions.

The Key Role of Hepcidin-25 in Anemia in Multiple Myeloma Patients with Renal Impairment

Background and objectives: Anemia is common in multiple myeloma (MM) and is caused by a complex pathomechanism, including impaired iron homeostasis. Our aim is to evaluate the biomarkers of iron turnover: serum soluble transferrin receptor (sTfR) and hepcidin-25 in patients at various stages of MM in relation with markers of anemia, iron status, inflammation, renal impairment and burden of the disease and as predictors of mortality. Materials and methods: Seventy-three MM patients (six with smoldering and 67 with symptomatic disease) were recruited and observed for up to 27 months. Control group included 21 healthy individuals. Serum sTfR and hepcidin were measured with immunoenzymatic assays. Results: MM patients with and without anemia had higher sTFR compared to controls, while only anemic patients had higher hepcidin-25. Both hepcidin-25 and sTfR were higher in anemic than non-anemic patients. Higher hepcidin-25 (but not sTfR) was associated with increasing MM advancement (from smoldering to International Staging System stage III disease) and with poor response to MM treatment, which was accompanied by lower blood hemoglobin and increased anisocytosis. Neither serum hepcidin-25 nor sTfR were correlated with markers of renal impairment. Hepcidin-25 predicted blood hemoglobin in MM patients independently of other predictors, including markers of renal impairment, inflammation and MM burden. Moreover, both blood hemoglobin and serum hepcidin-25 were independently associated with patients’ 2-year survival. Conclusions: Our results suggest that hepcidin-25 is involved in anemia in MM and its concentrations are not affected by kidney impairment. Moreover, serum hepcidin-25 may be an early predictor of survival in this disease, independent of hemoglobin concentration. It should be further evaluated whether including hepcidin improves the early diagnosis of anemia in MM.

Urinary Activin A: A Novel Biomarker for Human Acute Kidney Injury

Activin is a multifunctional cytokine belonging to the transforming growth factor (TGF)-β superfamily that regulates the growth and differentiation of cells in various organs. We previously reported that activin A, which is absent in normal kidneys, was significantly increased in the ischemic kidney, and that the blockade of activin action by follistatin, an activin antagonist, significantly enhanced tubular regeneration after renal ischemia, suggesting that activin A acts as an endogenous inhibitor of tubular repair after kidney injury in rodents. However, the role of activin A in human acute kidney injury (AKI) remains unclear. In this analysis, we measured serum and urinary activin A in human AKI (n = 39) and tested if activin A might serve as a biomarker for AKI. Urinary activin A, which was undetectable in healthy controls, was significantly increased in AKI (0.0 ± 0.0 vs. 173.4 ± 58.8 pg/mL, p < 0.05). The urinary activin A level in patients with AKI stage 3, was significantly higher than that in patients with AKI stages 1 and 2. Patients who required renal replacement therapy (RRT) had a significantly higher urinary activin A level than patients who did not require RRT. Urinary activin A might be a useful non-invasive biomarker for the severity of AKI.

Visceral fat-specific regulation of plasminogen activator inhibitor-1 in aged septic mice

Elevated plasma levels of plasminogen activator inhibitor-1 (PAI-1) are documented in patients with sepsis and levels positively correlate with disease severity and mortality. Our previous work demonstrated that visceral adipose tissues (VAT) are a major source of PAI-1, especially in the aged (murine endotoxemia), that circulating PAI-1 protein levels match the trajectory of PAI-1 transcript levels in VAT (clinical sepsis), and that PAI-1 in both VAT and plasma are positively associated with acute kidney injury (AKI) in septic patients. In the current study utilizing preclinical sepsis models, PAI-1 tissue distribution was examined and cellular sources, as well as mechanisms mediating PAI-1 induction in VAT, were identified. In aged mice with sepsis, PAI-1 gene expression was significantly higher in VAT than in other major organs. VAT PAI-1 gene expression correlated with PAI-1 protein levels in both VAT and plasma. Moreover, VAT and plasma levels of PAI-1 were positively associated with AKI markers, modeling our previous clinical data. Using explant cultures of VAT, we determined that PAI-1 is secreted robustly in response to recombinant transforming growth factor β (TGFβ) and tumor necrosis factor α (TNFα) treatment; however, neutralization was effective only for TNFα indicating that TGFβ is not an endogenous modulator of PAI-1. Within VAT, TNFα was localized to neutrophils and macrophages. PAI-1 protein levels were fourfold higher in stromal vascular fraction (SVF) cells compared with mature adipocytes, and among SVF cells, both immune and nonimmune compartments expressed PAI-1 in a similar fashion. PAI-1 was localized predominantly to macrophages within the immune compartment and preadipocytes and endothelial cells within the nonimmune compartment. Collectively, these results indicate that induction and secretion of PAI-1 from VAT is facilitated by a complex interaction among immune and nonimmune cells. As circulating PAI-1 contributes to AKI in sepsis, understanding PAI-1 regulation in VAT could yield novel strategies for reducing systemic consequences of PAI-1 overproduction.

The Role of Alpha-1-Acid Glycoprotein in the Diagnosis and Treatment of Crush Syndrome-Induced Acute Kidney Injury

BACKGROUND

Crush syndrome (CS) is the most common cause of deaths following earthquakes and other disasters. The pathogenesis of CS has yet to be fully elucidated. Thus, clinical choice of ideal drug treatments for CS remains deficient.

METHODS AND RESULTS

In this study, we first evaluated the relation between extrusion force and the severities of CS. Rats were exposed to different extrusion forces: 1 kg, 3 kg, 5 kg, and 8 kg, respectively. Survival rates, crushed muscle tissue edema, serum biochemical parameters, and histopathological staining were used to assess severity. Our results showed that there were no statistical differences in survival rate or changes in thigh circumference among the different extrusion forces groups. However, serum levels of potassium, creatine kinase, blood urea nitrogen, creatinine, and myoglobin were elevated at 12- and 24-h post-decompression in 5 kg and 8 kg groups, compared with 1 kg and 3 kg groups. Histopathological staining demonstrated that the degree of organ damage to kidney, muscle, and lung tissues correlated with increasing extrusion force. We next analyzed changes in serum protein profiles in 3 kg or 5 kg extrusion pressure groups. A total of 76 proteins (20 upregulated, 56 downregulated) were found to be altered at all three time points (0, 12, and 72 h) post-decompression, compared with the control group. Three common upregulated proteins alpha-1-acid glycoprotein (α1-AGP), neutrophil gelatinase-associated lipocalin (NGAL), and Haptoglobin were selected for validation of increased expression. α1-AGP was explored as a treatment for CS-induced acute kidney injury (AKI). Intraperitoneal injection of α1-AGP protected kidneys from CS-induced AKI by regulating TNF-α and IL-6 production, attenuating neutrophil recruitment, and reducing renal cell apoptosis.

CONCLUSION

Our findings demonstrated that the severity of crush injury is causally related to extrusion pressure and increase in blood serum markers. Our identification of the biomarker and treatment candidate, α1-AGP, suggests its implication in predicting the severity of CS and its use as a mediator of CS-induced AKI, respectively.

Relation of Baseline Neutrophil Gelatinase-Associated Lipocalin (NGAL) Levels and Contrast-Induced Nephropathy following Percutaneous Coronary Intervention among Chronic Kidney Disease Patients

BACKGROUND

The risk of contrast-induced acute kidney injury (CI-AKI) following coronary intervention is particularly high among patients with chronic kidney disease (CKD). Among these patients, baseline neutrophil gelatinase-associated lipocalin (NGAL), a marker of tubular damage, reflects the severity of renal impairment. We evaluated whether the baseline serum NGAL level may be a marker for the development of CI-AKI following percutaneous coronary intervention (PCI).

METHODS

Eighty-eight CKD patients treated with PCI were included. Serum NGAL levels were drawn upon hospital admission. Receiver operator characteristic (ROC) methods were used to identify the optimal sensitivity and specificity for the observed NGAL level compared with the estimated glomerular filtration rate (eGFR) calculated for patients with CI-AKI.

RESULTS

Overall CI-AKI incidence was 43%. Baseline serum NGAL levels were significantly higher in patients with CI-AKI than in patients without CI-AKI (150 vs. 103 ng/mL, p < 0.001). According to the ROC curve, baseline NGAL levels performed better than eGFR to predict CI-AKI (AUC 0.753 vs. 0.604), with the optimal cutoff value for baseline NGAL to predict CI-AKI being 127 ng/mL (sensitivity of 68% and specificity of 68%, p < 0.001). In a multivariate logistic regression model, the NGAL level >127 ng/mL ng/mL was independently associated with CI-AKI (HR 9.84, 95% CI: 1.96-40.3; p = 0.01).

CONCLUSION

Baseline serum NGAL levels in CKD patients may identify a high-risk population for CI-AKI following PCI. Further studies on larger populations are required to validate the potential utility of NGAL measurements in monitoring specific CKD-associated conditions.

Serial urinary neutrophil gelatinase associated lipocalin in pediatric diabetic ketoacidosis with acute kidney injury

BACKGROUND

Acute kidney injury (AKI) due to Diabetic Ketoacidosis (DKA) is rather common. Novel biomarkers to diagnose AKI are being increasingly used in different settings. The use of urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in predicting persistent AKI in pediatric DKA cases is still not thoroughly investigated.

METHODS

This was a secondary analysis of Saline versus Plasma-Lyte in Ketoacidosis (SPinK) trial data; 66 children (> 1 month-12 years) with DKA, defined by the International Society for Pediatric and Adolescent Diabetes (ISPAD), were analyzed. Children with cerebral edema, chronic kidney disease and those who received pre-referral fluids and/or insulin were excluded. uNGAL and urine NGAL-creatinine ratio (uNCR) at 0 and 24 h were measured in all. Persistent AKI was defined as a composite outcome of continuance of AKI defined by the Kidney Disease Improving Global Outcomes (KDIGO) stage 2 or 3 beyond 48 h from AKI onset, progression of AKI from either KDIGO stage 0 or 1 to a worse stage, need of renal replacement therapy or death.

MAIN OUTCOMES

Thirty-five (53%) children had AKI at admission; 32 (91.4%) resolved within 48 h. uNGAL was significantly higher in the AKI group at admission [79.8 ± 27.2 vs 54.6 ± 22.0, p = 0.0002] and at 24 h [61.4 ± 28.3 vs 20.2 ± 14.5, p = 0.0003]. Similar trend was observed with uNCR at admission [6.7 ± 3.7 vs 4.1 ± 2.6, p = 0.002] and at 24 h [6.3 ± 2.5 vs 1.2 ± 1.0, p = 0.01]. Furthermore, uNGAL at admission showed a moderate positive linear correlation with serum creatinine. Additionally, elevated uNGAL at 0 and 24 h correlated with corresponding KDIGO stages. Admission uNGAL >88 ng/ml and uNCR of >11.3 ng/mg had a sensitivity of 66% and 67%, specificity of 76% and 95%, and Area under the receiver operating characteristic curve (AUC) of 0.78 and 0.89 respectively for predicting persistent AKI at 48 h.

CONCLUSIONS

Majority of AKI resolved with fluid therapy. While uNGAL and uNCR both correlated with serum creatinine and AKI stages, serial uNCR was a better predictor of persistent AKI than uNGAL alone. However, feasibility of routine uNGAL measurement to predict persistent AKI in DKA needs further elucidation.

TRIAL REGISTRATION

This was a secondary analysis of the data of SPinK trial [CTRI/2018/05/014042 ( ctri.nic.in )].

Renal fibrosis due to multiple cisplatin treatment is exacerbated by kinin B1 receptor antagonism

Cisplatin is a widely used chemotherapeutic drug, but its side effects are a major limiting factor. Nephrotoxicity occurs in one third of patients undergoing cisplatin treatment. The acute tubular injury caused by cisplatin often leads to a defective repair process, which translates into chronic renal disorders. In this way, cisplatin affects tubular cells, and maladaptive tubules regeneration will ultimately result in tubulointerstitial fibrosis. Kinins are well known for being important peptides in the regulation of inflammatory stimuli, and kinin B1 receptor deficiency and antagonism have been shown to be beneficial against acute cisplatin nephrotoxicity. This study aimed to analyze the effects of kinin B1 receptor deletion and antagonism against repeated cisplatin-induced chronic renal dysfunction and fibrosis. Both the deletion and the antagonism of B1 receptor exacerbated cisplatin-induced chronic renal dysfunction. Moreover, the inhibition of B1 receptor increased tubular injury and tubulointerstitial fibrosis after repeated treatment with cisplatin. The balance between M1/M2 macrophage polarization plays an important role in renal fibrosis. Kinin B1 receptor antagonism had no impact on M1 markers when compared to cisplatin. However, YM1, an M2 marker and an important molecule for the wound healing process, was decreased in mice treated with kinin B1 receptor antagonist, compared to cisplatin alone. Endothelin-1 levels were also increased in mice with B1 receptor inhibition. This study showed that kinin B1 receptor inhibition exacerbated cisplatin-induced chronic renal dysfunction and fibrosis, associated with reduced YM1 M2 marker expression, thus possibly affecting the wound healing process.

Effects of Dexmedetomidine on Patients Undergoing Laparoscopic Surgery for Colorectal Cancer

BACKGROUND

Pneumoperitoneum during laparoscopic surgery has a systemic impact on the renal system and might contribute to acute kidney injury or postoperative renal dysfunction. However, effective preventive strategies are still lacking. We aimed to explore the effects of dexmedetomidine (DEX) on kidney and other organ function in patients undergoing elective laparoscopic surgery for colorectal cancer.

MATERIALS AND METHODS

Fifty-six patients were randomly enrolled into the Control or DEX group. The DEX group received 1 µg kg^-1 DEX intravenously within 10 min followed by a maintenance dose of 0.5 µg kg^-1 h^-1 infused until 30 min before closing the peritoneum. In the Control group, 0.9% sodium chloride was administered as a placebo. The primary outcome was serum neutrophil gelatinase-associated lipocalin (NGAL) levels reflecting kidney injury. Secondary outcomes included variables reflecting the kidney, intestinal injury and systemic inflammatory response.

RESULTS

NGAL levels were significantly lower in the DEX group than in the Control group at 1 d and 5 d postoperatively (107.5 ± 55.6 ng mL^-1versus 179.5 ± 78.2 ng mL^-1; 70.3 ± 45.8 ng mL^-1versus 135.2 ± 59.6 ng mL^-1, P < 0.001), while the BUN and Cr levels showed no differences between the groups. Serum DAO activity was significantly lower in the DEX group patients 24 h after surgery. Moreover, I-FABP levels were markedly lower at 2 h and 24 h postoperatively in the DEX group than in the Control group (P < 0.001).

CONCLUSIONS

Perioperative DEX administration may potentially confer kidney and intestinal protection during laparoscopic surgery for colorectal cancer patients.

Neutrophil Gelatinase-Associated Lipocalin as an Early Predictor of Contrast-Induced Nephropathy Following Endovascular Aortic Repair for Abdominal Aortic Aneurysm

To investigate serum neutrophil gelatinase-associated lipocalin (sNGAL) and urine neutrophil gelatinase-associated lipocalin (uNGAL) as early predictors of contrast-associated acute kidney injury(contrast-induced nephropathy)following endovascular aortic repair for abdominal aortic aneurysm. Prospective cohort study. Subjects included 202 consecutive patients with abdominal aortic aneurysm diagnosed between February 2016 and October 2018. We divided the patients into 2 groups: contrast-induced nephropathy (CIN) (n = 26) and non-CIN (n = 176). We assessed correlations between sNGAL and uNGAL concentrations and standard renal markers at baseline, 6, 24, and 48 hours post-procedure. We constructed conventional receiver operating characteristic (ROC) curves and calculated the area under the curve to assess SCr, eGFR, sNGAL, and uNGAL performance. We derived biomarker cutoff levels from ROC analysis results to maximize sensitivity and specificity values. The CIN incidence within our cohort was 12.9%. sNGAL levels correlated significantly with SCr and eGFR at baseline, 6, and 24 hours post-contrast medium exposure. Similarly, uNGAL levels correlated with SCr and estimated glomerular filtration rate (eGFR) at baseline, 6, and 24 hours post-exposure. sNGAL and uNGAL were significantly elevated as early as 6 hours post-endotherapy in the CIN group; there were only minor changes in the non-CIN group. SCr was also significantly elevated in the CIN group, but not until 48 hours post-catheterization. Both sNGAL and uNGAL may be more accurate than SCr and eGFR as early biomarkers of CIN in patients with abdominal aortic aneurysm undergoing endovascular therapy.

Neutrophil gelatinase-associated lipocalin as a biomarker for short-term outcomes among trauma patients: A single-center observational study

BACKGROUND

Urinary biomarkers for organ dysfunction could predict the outcomes of severe trauma patients. However, the use of neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker of trauma is not well studied.

OBJECTIVES

To evaluate the association between the short-term prognosis of trauma patients and NGAL levels.

METHODS

We conducted a single center study and compared predictive performances between NGAL levels and the trauma severity.

RESULTS

A total of 104 patients were included in the study. Patients were divided into two groups based on ISS score of 16. There was no significant difference in patient characteristics based on trauma severity. However, the lactate level was significantly higher in the more severe group. There was a significant association between urinary NGAL levels and trauma severity indicators, such as intensive care unit stay (ICU) (p = 0.005) and emergency care unit (ECU) stay (p = 0.049). In addition, receiver operating curve analysis showed that as a predictor, NGAL could be used for detecting severity with moderate precision, especially for short-term outcomes (specificity 70.6 for ICU and 69.0 for ECU stay).

CONCLUSION

In this study, we revealed that the level of NGAL could predict the degree of invasiveness in trauma patients with moderate precision and estimate the duration of treatment during the acute phase. It is necessary to examine the validity of the findings of this study using a prospective, cohort, and multi-center collaborative study design.

The Assessment of the Usefulness of Selected Markers in the Diagnosis of Chronic Kidney Disease in Children

INTRODUCTION

The kidney deterioration, which starts in childhood often leads to end-stage renal failure in the future. Therefore, searching for an early, sensitive, and specific biomarkers became a paramount for chronic kidney disease diagnosis. The aim of this study was the assessment of markers: KIM-1, FGF-23, NAG, NGAL, and uromodulin for diagnosis of preclinical phase of the disease in children.

PATIENTS AND METHODS

59 children (15 boys, 44 girls from 6 months to 17 years old) with kidney disorders, which had clinical indications for renoscintigraphy, were included in the study. All patients were divided depending on the result of renoscintigraphy (renal scarring vs normal kidney picture) and depending on the level of estimated glomerular filtration rate (glomerular hyperfiltration vs normal filtration rate). The concentration of uromoduline, KIM-1, FGF-23, NAG, and NGAL in serum and of NGAL and uromoduline in urine were measured in all studied groups.

RESULTS

The children with glomerular hyperfiltration had a statistically significantly higher serum values of FGF-23 and NGAL than the children with normal filtration rate (P < .05). There were no statistically significant differences in serum concentrations of tested markers in children with renal scars in comparison to children with normal renal image. There was no statistically significant difference in the concentration of tested markers in urine.

CONCLUSIONS

The study confirmed the possible usefulness of FGF-23 and NGAL in detecting the preclinical-stage of renal disease associated with glomerular hyperfiltration in children. The study do not allow to indicate markers, which could be useful in the early diagnosis of kidney damage visible in the scintigraphic examination.

Using urinary neutrophile gelatinase-associated lipocalin for prognosticate renal dysfunction in children with familial Mediterranean fever the study design: a pilot study

BACKGROUND

The most important finding that affects the prognosis in Familial Mediterranean Fever is renal amyloidosis. The aim of the present study was to analyze neutrophil gelatinase-associated lipocalin levels in the urine, and to investigate whether it may be used as an early marker for renal involvement.

METHODS

Forty attack-free children followed by diagnosis of Familial Mediterranean Fever with age range of 5 and 18 years, and 38 healthy children with similar ages and genders were enrolled into the study. Hemogram, sedimentation, C-reactive protein, urine analysis, creatinine in the spot urine, microalbumin and urinary neutrophil gelatinase-associated lipocalin levels were analyzed and evaluated statistically in the patients and controls.

RESULTS

There was not any statistically significant difference between the patient and control groups for age, gender, height and body weight. Although there was not any clinical sign of attack in the patient group, sedimentation, C-reactive protein and fibrinogen levels were significantly higher than the control group (p = 0.002, p = 0.023, and p = 0.006, respectively). Similarly, urinary neutrophil gelatinase-associated lipocalin level and urinary creatinine ratio were significantly higher in the patient group (p = 0.0001, p = 0.011, respectively). We found a positive correlation between uNGAL level and uNGAL/uCr ratio and number of attacks per year in FMF patients (r = 0.743, p = 0.001 and r = 0.516, p = 0.001; respectively).

CONCLUSIONS

Detection of significantly higher levels of urinary neutrophil gelatinase-associated lipocalin level and urinary neutrophil gelatinase-associated lipocalin level to creatinine ratio were suggested as urinary neutrophil gelatinase-associated lipocalin level as a non-invasive marker for renal involvement better than microalbumin.

Liver-type fatty acid-binding protein and neutrophil gelatinase-associated lipocalin in cats with chronic kidney disease and hyperthyroidism

BACKGROUND

Liver-type fatty acid-binding protein (L-FABP) and neutrophil gelatinase-associated lipocalin (NGAL) are candidate biomarkers for the detection of early chronic kidney disease (CKD) in cats.

OBJECTIVE

To evaluate urinary and serum L-FABP and NGAL concentrations in CKD cats and in hyperthyroid cats before and after radioiodine (¹³¹ I) treatment.

ANIMALS

Nine CKD cats, 45 healthy cats and hyperthyroid cats at 3 time points including before (T0, n = 49), 1 month (T1, n = 49), and 11 to 29 months after (T2, n = 26) ¹³¹ I treatment.

METHODS

Cross-sectional and longitudinal study. Serum L-FABP (sL-FABP), serum NGAL (sNGAL), urinary L-FABP (uL-FABP), and urinary NGAL (uNGAL) were compared between the 3 groups and between hyperthyroid cats before and after treatment. Data are reported as median (min-max).

RESULTS

CKD cats had significantly higher sL-FABP (13.50 [3.40-75.60] ng/ml) and uL-FABP/Cr (4.90 [0.97-2139.44] µg/g) than healthy cats (4.25 [1.34-23.25] ng/ml; P = .01 and 0.46 [0.18-9.13] µg/g; P < .001, respectively). Hyperthyroid cats at T0 had significantly higher uL-FABP/Cr (0.94 [0.15-896.00] µg/g) than healthy cats (P < .001), thereafter uL-FABP/Cr significantly decreased at T2 (0.54 [0.10-76.41] µg/g, P = .002). For the detection of CKD, uL-FABP/Cr had 100% (95% confidence interval [CI], 66.4-100.0) sensitivity and 93.2% (95% CI, 81.3-98.6) specificity. There were no significant differences in sNGAL and uNGAL/Cr between the 3 groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

L-FABP, but not NGAL, is a potential biomarker for the detection of early CKD in cats. Utility of uL-FABP to predict azotemia after treatment in hyperthyroid cats remains unknown.

Knockout of NGAL aggravates tubulointerstitial injury in a mouse model of diabetic nephropathy by enhancing oxidative stress and fibrosis

Neutrophil gelatinase-associated lipocalin (NGAL), also called lipocalin 2, is considered a promising biomarker for acute and chronic kidney injuries. Several studies have demonstrated that its levels increase in plasma and urine in diabetic nephropathy (DN), and its urine concentration increases upon kidney function deterioration. However, its role in DN progression remains unclear. The current study used in vitro gene expression knockdown in human proximal tubular cell line human kidney (HK)2 to investigate the role of NGAL in oxidation and extracellular matrix secretion under high-glucose (HG) incubation. In addition, type 1 diabetes was induced in vivo in knockout NGAL^-/- and wild-type mice in order to investigate role of NGAL in the progression of DN. The results demonstrated that NGAL knockdown in HK2 cells significantly increased oxidative stress under HG stimulation tested by flow cytometry, and increased the secretion of interleukin-6, fibronectin (FN) and collagen IV examined by ELISA. Western blotting demonstrated that the phosphorylation of Smad2/3 also increased in HK2 cells under transforming growth factor-β1 stimulation. In vivo experiments demonstrated that diabetic NGAL^-/- mice showed deteriorated renal function compared with that of diabetic wild-type mice. Histopathological analysis suggests that diabetic NGAL^-/- mice had more serious glomerulosclerosis and tubular vascular degeneration than wild-type mice. Immunohistochemistry suggested that the absence of NGAL lead to increased FN deposition in glomeruli in a mouse model of DN. In conclusion, NGAL appears to have renal protective effects by slowing down the progression of DN, and its effect may be associated with a reduction in oxidation, fibrosis and inflammation.

Indicator of early kidney injury in adolescents with polycystic ovary syndrome: Can urine NGAL level be?

INTRODUCTION AND PURPOSE

The Urinary Neutrophil-gelatinase associated lipocalin (NGAL) levels which are a biomarker for early diagnosis of kidney damage that may develop in patients with Polycystic Ovary Syndrome (PCOS) were investigated in the study.

MATERIAL AND METHODS

The 30 patients diagnosed with Polycystic Ovarian Syndrome between the ages of 13 and 18 who applied to the Yuzuncu Yil University General Children's Outpatient Clinic were included in the PCOS group and 30 healthy adolescents without any known acute or chronic illness and drug use were included in the control group.

FINDINGS

Urine NGAL value was 842.204 ± 21.561 in PCOS group and 775.379 ± 23.98 in control group. NGAL level in PCOS group was statistically significantly higher than control group (p: .045). When we examine the relationship between dyslipidemia and PCOS; While dyslipidemia was positive in 10 (33.7%) patients in the PCOS group, it was negative in 20 (66.7%) patients. While 1 patient had dyslipidemia, 29 patients did not have dyslipidemia in the control group. A significant relationship was found between dyslipidemia and PCOS (p: .005).

CONCLUSION

We found that subclinical kidney dysfunction started in early stage patients in PCOS in our study. The urine NGAL level was thought to increase in response to increased oxidative stress in PCOS. We found no relationship between, insulin resistance and urea, BUN, creatinine and NGAL levels. However, we found a negative correlation between NGAL level and LDL. In addition, dyslipidemia, insulin resistance and ALT elevation were detected in the PCOS group.

Current Challenges and Future Perspectives of Renal Tubular Dysfunction in Diabetic Kidney Disease

Over decades, substantial progress has been achieved in understanding the pathogenesis of proteinuria in diabetic kidney disease (DKD), biomarkers for DKD screening, diagnosis, and prognosis, as well as novel hypoglycemia agents in clinical trials, thereby rendering more attention focused on the role of renal tubules in DKD. Previous studies have demonstrated that morphological and functional changes in renal tubules are highly involved in the occurrence and development of DKD. Novel tubular biomarkers have shown some clinical importance. However, there are many challenges to transition into personalized diagnosis and guidance for individual therapy in clinical practice. Large-scale clinical trials suggested the clinical relevance of increased proximal reabsorption and hyperfiltration by sodium-glucose cotransporter-2 (SGLT2) to improve renal outcomes in patients with diabetes, further promoting the emergence of renal tubulocentric research. Therefore, this review summarized the recent progress in the pathophysiology associated with involved mechanisms of renal tubules, potential tubular biomarkers with clinical application, and renal tubular factors in DKD management. The mechanism of kidney protection and impressive results from clinical trials of SGLT2 inhibitors were summarized and discussed, offering a comprehensive update on therapeutic strategies targeting renal tubules.

Effectiveness of Plasma and Urine Neutrophil Gelatinase-Associated Lipocalin for Predicting Acute Kidney Injury in High-Risk Patients

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a useful biomarker for acute kidney injury (AKI) prediction. However, studies on whether using both plasma NGAL (PNGAL) and urine NGAL (UNGAL) can improve AKI prediction are limited. We investigated the best approach to predict AKI in high-risk patients when using PNGAL and UNGAL together.

METHODS

We enrolled 151 AKI suspected patients with one or more AKI risk factors. We assessed the diagnostic performance of PNGAL and UNGAL for predicting AKI according to chronic kidney disease (CKD) status by determining the areas under the receiver operating curve (AuROC). Independent predictors of AKI were assessed using univariate and multivariate logistic regression analyses.

RESULTS

In the multivariate logistic regression analysis for all patients (N=151), Model 2 and 3, including PNGAL (P=0.012) with initial serum creatinine (S-Cr), showed a better AKI prediction power (R2=0.435, both) than Model 0, including S-Cr only (R2=0.390). In the non-CKD group (N=135), the AuROC of PNGAL for AKI prediction was larger than that of UNGAL (0.79 vs 0.66, P=0.010), whereas in the CKD group (N=16), the opposite was true (0.94 vs 0.76, P=0.049).

CONCLUSIONS

PNGAL may serve as a useful biomarker for AKI prediction in high-risk patients. However, UNGAL predicted AKI better than PNGAL in CKD patients. Our findings provide guidance for selecting appropriate specimens for NGAL testing according to the presence of CKD in AKI high-risk patients.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) Is Related with the Proteinuria Degree and the Microscopic Kidney Findings in Leishmania-Infected Dogs

Early diagnosis of renal damage in Leishmania infected dogs may allow appropriate treatments and prevent some deaths. This study investigates neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker of kidney disease in dogs experimentally infected with Leishmania infantum. Serum, urine, and kidney samples were collected from 30 infected beagle dogs and six uninfected control dogs. Based on proteinuria and azotemia values, dogs were initially classified. NGAL was measured in urine and serum samples. Then, the urinary NGAL to creatinine ratio (uNGAL/C) was calculated. Kidney samples were taken for histopathological studies, and the dogs were classified according to the severity of glomerular and tubulointerstitial lesions. In Leishmania-infected dogs, the uNGAL/C was significantly higher in proteinuric non-azotemic dogs compared with non-proteinuric non-azotemic dogs (p = 0.038). Serum NGAL (sNGAL) concentration did not differ between groups. Microscopic studies revealed several degrees of glomerulonephritis and slight focal lymphoplasmacytic interstitial nephritis in 89% and 55% of infected dogs, respectively. Urinary protein to creatinine ratio (UPC) and uNGAL/C were significantly higher in dogs with affected glomeruli compared to infected dogs without renal lesions (p = 0.045 and p = 0.043, respectively). The results show that uNGAL/C correlates with proteinuria and the presence of moderate glomerular lesions in non-azotemic dogs experimentally infected with L. infantum.

Evaluating the Relationship of GDF-15 with Clinical Characteristics, Cardinal Features, and Survival in Multiple Myeloma

Growth differentiation factor 15 (GDF-15), a member of the transforming growth factor-β superfamily, participates in processes associated with myeloma development and its end-organ complications. It plays a significant role in both physiological and abnormal erythropoiesis and regulates iron homeostasis through modulation of hepcidin. It is abnormally secreted in marrow stromal cells of patients with multiple myeloma (MM), which may reflect the tumor microenvironment. We analyzed the associations of serum GDF-15 with clinical characteristics of 73 MM patients (including asymptomatic MM) and the laboratory indices of renal function, anemia, and inflammation. Baseline serum GDF-15 was studied as the predictor of two-year survival. We defined five clinically relevant subgroups of patients (symptomatic MM only, patients with and without remission, patients on chemotherapy, and without treatment). Increased GDF-15 concentrations were associated with more advanced MM stage, anemia, renal impairment (lower glomerular filtration and higher markers of tubular injury), and inflammation. Most of the results were confirmed in the subgroup analysis. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin were associated with GDF-15 independently of other variables. In the studied MM patients, GDF-15 did not significantly predict survival (p = 0.06). Our results suggest that serum GDF-15 reflects myeloma burden and shares a relationship with several markers of prognostic significance, as well as major manifestations.

Urine neutrophil gelatinase-associated lipocalin concentration in healthy newborns during the first three postnatal days

Introduction

Urine neutrophil gelatinase-associated lipocalin (uNGAL) is a biochemical marker significant for early prediction of acute kidney injury in adults. However, it has not been examined sufficiently among the infant population, particularly newborns in terms of reference values. The aim of our study was to determine the concentration of uNGAL in healthy term newborns and to determine if there was a difference in uNGAL concentration according to gender, postnatal age and birth weight.

Materials and methods

Our study involved 81 healthy term newborns birth (≥ 37 weeks, Apgar score ≥ 8 in the first minute after birth, CRP < 5 mg/L). Urine NGAL was measured using chemiluminescent microparticle immunoassay (CMIA) within 72 hours after birth, on Architect plus ci8200 analyser (Abbott, Chicago, USA). Data were analysed using Statistica software.

Results

The median concentration of uNGAL in the whole study group of healthy term newborns was 27.1 ng/mL (16.5-56.0 ng/mL) (newborn girls, 27.1 ng/mL (15.8-47.9 ng/mL); newborn boys, 27.9 ng/mL (16.5-61.0 ng/mL), P = 0.941). Median uNGAL concentration according to postnatal age expressed in days was 28.2 ng/mL (11.7-57.2 ng/mL) 1^st day, 28.9 ng/mL (16.5-64.2 ng/mL) 2^nd day and 23.9 ng/mL (20.2-46.6) 3^rd day, P = 0.863. Regarding birth weight for newborns < 3500 g, median concentration was 25.0 ng/mL (16.5-45.4 ng/mL) and for weight ≥ 3500 g 30.6 ng/mL (16.5-64.2 ng/mL), P = 0.455.

Conclusions

There were no significant difference in uNGAL concentration in relation to gender, postnatal age and birth weight.

PPAR-α Deletion Attenuates Cisplatin Nephrotoxicity by Modulating Renal Organic Transporters MATE-1 and OCT-2

Cisplatin is a chemotherapy drug widely used in the treatment of solid tumors. However, nephrotoxicity has been reported in about one-third of patients undergoing cisplatin therapy. Proximal tubules are the main target of cisplatin toxicity and cellular uptake; elimination of this drug can modulate renal damage. Organic transporters play an important role in the transport of cisplatin into the kidney and organic cations transporter 2 (OCT-2) has been shown to be one of the most important transporters to play this role. On the other hand, multidrug and toxin extrusion 1 (MATE-1) transporter is the main protein that mediates the extrusion of cisplatin into the urine. Cisplatin nephrotoxicity has been shown to be enhanced by increased OCT-2 and/or reduced MATE-1 activity. Peroxisome proliferator-activated receptor alpha (PPAR-α) is the transcription factor which controls lipid metabolism and glucose homeostasis; it is highly expressed in the kidneys and interacts with both MATE-1 and OCT-2. Considering the above, we treated wild-type and PPAR-α knockout mice with cisplatin in order to evaluate the severity of nephrotoxicity. Cisplatin induced renal dysfunction, renal inflammation, apoptosis and tubular injury in wild-type mice, whereas PPAR-α deletion protected against these alterations. Moreover, we observed that cisplatin induced down-regulation of organic transporters MATE-1 and OCT-2 and that PPAR-α deletion restored the expression of these transporters. In addition, PPAR-α knockout mice at basal state showed increased MATE-1 expression and reduced OCT-2 levels. Here, we show for the first time that PPAR-α deletion protects against cisplatin nephrotoxicity and that this protection is via modulation of the organic transporters MATE-1 and OCT-2.

Comparison of Blood Pressure and Kidney Markers between Adolescent Former Preterm Infants and Term Controls

BACKGROUND

Preterm infants are at an increased risk of developing hypertension and chronic kidney disease later in life. No recommendations exist for blood pressure (BP) and renal follow up for these patients.

AIM

To compare BP and serum and urinary kidney markers between preterm-born adolescents and term-born controls.

METHODS

BP measurements in 51 preterm-born (≤32 weeks gestational age) and 82 term-born adolescents at the age of 10-15 years were conducted. Stepwise regression analysis explored the association between BP and participant characteristics. Kidney markers measured in the serum and urine were creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and uromodulin. Kidney markers measured in the serum were cystatin C, beta-2 microglobulin, and beta trace protein.

RESULTS

Systolic BP was significantly higher in preterm boys compared with term boys, but not in girls, and low birth weight was associated with higher BP in boys. In the preterm group, maternal hypertension/preeclampsia and adolescent height were associated with higher systolic BP. Serum creatinine and NGAL were significantly higher in the preterm group.

CONCLUSIONS

Our study confirms an inverse sex-dependant relationship between birth weight and BP at adolescent age. The higher serum creatinine and NGAL in the preterm group may indicate that premature birth affects kidney function in the long term.

Neutrophil gelatinase-associated lipocalin as an early predictor of contrast-induced nephropathy following endovascular therapy for arteriosclerosis obliterans

Serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) are standard biomarkers of contrast-induced nephropathy (CIN). However, recent studies suggest that serum neutrophil gelatinase-associated lipocalin (sNGAL) and urine neutrophil gelatinase-associated lipocalin (uNGAL) may be better predictors, particularly within 24 hours of contrast medium exposure.We conducted a prospective, observational cohort study of 107 consecutive patients diagnosed with arteriosclerosis obliterans between February 2016 and October 2018. We divided the patients into 2 groups: CIN (n = 22) and non-CIN (n = 85). We assessed the correlation between sNGAL and uNGAL concentrations and standard renal markers at baseline, 6, 24, and 48 hours post-procedure. We constructed conventional receiver operating characteristic (ROC) curves and calculated the area under the curve to assess the performance of SCr, eGFR, sNGAL, and uNGAL. We derived biomarker cutoff levels from ROC analysis to maximize sensitivity and specificity.The incidence of CIN within our cohort was 20.6%. sNGAL levels correlated significantly with SCr and eGFR at baseline, 6, 24, and 48 hours post-contrast medium exposure. Similarly, uNGAL levels correlated with SCr and eGFR at baseline, 24, and 48 hours post-exposure. sNGAL and uNGAL were significantly elevated as early as 6 hours post-catheterization in the CIN group, whereas only minor changes were observed in the non-CIN group. SCr was also significantly elevated in the CIN group, but not until 24 hours post-catheterization.Both sNGAL and uNGAL may be superior to SCr and eGFR as early biomarkers of CIN in patients with peripheral vascular disease undergoing endovascular therapy.

Prognostic value of dynamic plasma endostatin for the prediction of mortality in acute kidney injury: A prospective cohort study

Objective

The aim of the current study was to evaluate the value of plasma endostatin for predicting 30-day mortality of patients with acute kidney injury (AKI).

Methods

Patients who underwent non-cardiac major surgery and developed AKI in the first 48 hours after admission to the intensive care unit were consecutively included. Concentrations of plasma neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (Cys C), and endostatin were measured at three time points: 0, 24, and 48 hours after the AKI diagnosis. Clinical patient characteristics were recorded after AKI was diagnosed.

Results

A total of 256 new-onset AKI patients were enrolled. Of these, 48 (18.7%) patients died within 30 days. The difference in plasma endostatin values between 0 and 24 hours (ΔEndostatin-24h) yielded the best area under the curve (AUC) of 0.747 for predicting 30-day mortality in AKI patients; NGAL and Cys C achieved AUC of 0.672 and 0.647, respectively. The predictive AUC increased to 0.833 when ΔEndostatin-24h was combined with sequential organ failure assessment score and AKI classification.

Conclusion

Dynamic plasma endostatin is useful for predicting 30-day mortality in AKI patients. The predictive power of dynamic plasma endostatin can be significantly improved when it is combined with clinical patient data.

Mitochondrial pyruvate carrier: a potential target for diabetic nephropathy

Background

Mitochondrial dysfunction contributes to the pathogenesis of diabetic nephropathy (DN). Mitochondrial pyruvate carrier 1 (MPC1) and mitochondrial pyruvate carrier 2 (MPC2) play a bottleneck role in the transport of pyruvate into mitochondrial across the mitochondrial inner membrane. A previous study showed that increasing mitochondrial pyruvate carrier content might ameliorate diabetic kidney disease in db/db mice. However, the expression status of MPC1 and MPC2 in patients with DN is unclear.

Methods

Patients with primary glomerulonephropathy (PGN, n = 30), PGN with diabetes mellitus (PGN-DM, n = 30) and diabetic nephropathy (DN, n = 30) were included. MPC1 and MPC2 protein levels were examined by immunohistochemistry. The expression of MPC in different groups was evaluated by the Kruskal-Wallis test. Spearman’s rank correlation was performed for correlation analysis between MPC levels and clinical factors.

Results

Both MPC1 and MPC2 were localized in renal tubules. Levels of MPC1 and MPC2 were lower in DN patients than in PGN patients and in PGN patients with DM, whereas there were no differences in MPC1 and MPC2 levels among DN stage II to stage IV. Moreover, both MPC1 and MPC2 levels were significantly correlated with serum creatinine, BUN and eGFR in patients with DN, whereas no analogous trend was observed in nondiabetic kidney disease.

Conclusions

Our study indicated that MPC localized in renal tubules, which were significantly decreased in DN. MPC was associated with clinical features, especially those representing renal functions.

Urinary neutrophil gelatinase-associated lipocalin determines short-term mortality and type of acute kidney injury in cirrhosis

Background and Aim

Acute kidney injury increases mortality in cirrhotic patients by four fold. This study aimed to determine the usefulness of urinary neutrophil gelatinase-associated lipocalin (uNGAL) for differential diagnosis for acute kidney injury and for predicting short-term mortality in cirrhotic patients.

Methods

We enrolled 94 patients of decompensated cirrhosis. uNGAL was measured upon hospital admission in all patients. Patients with urinary tract infection and anuria were excluded. Patients were followed for 30 days or until death.

Results

Ten (9%) patients had normal kidney function, 9 (11.37%) stable chronic kidney disease, 32 (29.50%) prerenal azotemia, 33 (36.37%) hepatorenal syndrome (HRS), and 10 (13.64%) intrinsic acute kidney injury (iAKI). Prerenal azotemia had lower median uNGAL values compared to HRS and iAKI (95.50 vs 465.00 vs 1217.50, P < 0.001). uNGAL levels were significantly higher in patients who died within 30 days (717.17 ± 494.26 vs 331.65 ± 313.65 ng/mL, P -0.0017). On univariate analysis, serum creatinine (sCr), uNGAL, Model for End-Stage Liver Disease (MELD) score on admission, and length of stay were significant, and on multivariate analysis, uNGAL and hepatic encephalopathy (HE) were significant in predicting mortality.

Conclusions

uNGAL at baseline serves as an early marker in differentiating HRS, prerenal AKI, and iAKI in cirrhotic patients, where sCr values are not useful. Patients with higher uNGAL levels had higher transplant-free mortality at 30 days.