NGAL: a biomarker of acute kidney injury and other systemic conditions

Rat Model Investigation on the Role of Biomarkers in Hepatic Ischemia-Reperfusion Injury

OBJECTIVES

Liver function is affected by ischemiareperfusion. Ischemia-reperfusion injury to the liver often follows hepatobiliary surgery. Here, we investigated biomarkers of liver ischemia-reperfusion injury using an animal model.

MATERIALS AND METHODS

For this study, 24 male Sprague Dawley rats (146-188 g) were divided into 4 groups: group A was the control group, group B was the partial hepatic ischemia-reperfusion group, group C was the total hepatic ischemia-reperfusion group, and group D was the intermittent total hepatic ischemiareperfusion group. Laboratory liver function levels were measured before ischemia, after ischemia, and after reperfusion. We used liver and renal biopsies for histopathological examination at the end of the study.

RESULTS

After clamping and reperfusion, alanine aminotransferase and cystatin C levels in groups B, C, and D were significantly higher than levels in group A. In group B, after clamping, neutrophil gelatinaseassociated lipocalin levels were higher than in groups A and D, with significantly higher level than in group D after reperfusion. Neutrophil gelatinase-associated lipocalin levels decreased significantly in groups B, C, and D after reperfusion. There was significantly greater hepatic damage in groups B, C, and D compared with group A but no significant differences in renal injury scores among the groups. There was a significant positive correlation between hepatic damage and renal injury. With regard to histopathological examination versus laboratory results, a statistically significant positive correlation was shown between grade of hepatic damage and serum alanine aminotransferase and cystatin C levels. Similarly, there was a positive correlation between renal damage score and alanine aminotransferase level.

CONCLUSIONS

In our animal model, alanine amino - transferase and cystatin C levels tended to increase with ischemia-reperfusion injury levels but neutrophil gelatinase-associated lipocalin decreased during reperfusion. In liver ischemia, we suggest that neutrophil gelatinase-associated lipocalin may be an important biomarker for distinguishing the reperfusion phase.

Obesity-associated up-regulation of lipocalin 2 protects gastric mucosa cells from apoptotic cell death by reducing endoplasmic reticulum stress

Gastric mucosal injury is a less well known complication of obesity. Its mechanism remains to be further elucidated. Here, we explored the protective role of lipocalin 2 (LCN2) against endoplasmic reticulum stress and cell apoptosis in gastric mucosa in patients and mice with obesity. Through molecular and genetic analyses in clinical species, LCN2 secreted by parietal cells expression is elevated in obese. Immunofluorescence, TUNEL, and colorimetry results show that a more significant upregulation of pro-inflammatory factors and increased amount of apoptotic cells in gastric tissue sections in obese groups. Loss- and gain-of-function experiments in gastric epithelial cells demonstrate that increased LCN2 protected against obesity associated gastric injury by inhibiting apoptosis and improving inflammatory state. In addition, this protective effect was mediated by repressing ER stress. Our findings identify LCN2 as a gastric hormone could be a compensatory protective factor against gastric injury in obese.

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

Role of neutrophil gelatinase-associated lipocalin in renal cell carcinoma

Human neutrophil gelatinase-associated lipocalin (NGAL) is a glycoprotein present in a wide variety of tissues and cell types. It exists as a monomer of 25 kDa, a homodimer of 45 kDa or a heterodimer of 135 kDa (disulfide bound to latent matrix metalloproteinase-9). NGAL is considered the biochemical gold standard for the early diagnosis of acute kidney injury and has attracted much attention as a diagnostic biomarker. NGAL has controversial (i.e. both beneficial and detrimental) effects on cellular processes associated with tumor development, such as cell proliferation, survival, migration, invasion and drug resistance. Therefore, the present review aimed at clarifying the role of NGAL in renal cell carcinoma (RCC). Relevant studies of NGAL and RCC were searched in PubMed and relevant information about the structure, expression, function and mechanism of NGAL in RCC were summarized. Finally, the following conclusions could be drawn from the literature: i) NGAL can be detected in cancer tissues, serum and urine of patients with RCC; ii) NGAL is not a suitable diagnostic marker for early screening of RCC; iii) NGAL expression may be used to predict the prognosis of patients with RCC; and iv) Further research on NGAL may be helpful to decrease sunitinib resistance and find new treatment strategies for RCC.

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 updates on protein as biomarkers for diabetic kidney disease: a systematic review

BACKGROUND

In the past decade, researchers have been focused on discovering protein biomarkers for diabetic kidney disease. This paper aims to search for, analyze, and synthesize current updates regarding the development of these efforts.

METHODS

We systematically searched the ScienceDirect, SpringerLink, and PubMed databases for observational studies of protein biomarkers in patients with diabetes mellitus. We included studies published between January 2018 and April 2020, that were based on a population of patients with type-1 or type-2 diabetes mellitus aged ⩾18 years, with an observational design such as cross-sectional, case-control, or cohort studies. The dependent variable of the research results was in the form of protein biomarkers from urine, plasma, or serum.

RESULTS

Following the screening process, 20 research articles with available full text met the inclusion criteria. These could be categorized as glomerular biomarkers (ANGPTL4, beta-2 microglobulin, Smad1, and glypican-5); inflammatory biomarkers (MCP-1 and adiponectin); and tubular biomarkers (NGAL, VDBP, megalin, sKlotho, and KIM-1). The development of a panel of biomarkers showed more promising results than those for a single biomarker in diagnosing diabetic kidney disease.

CONCLUSION

All the biomarkers discussed in this review showed promising results for predicting diabetic kidney disease because they correlate with albuminuria, eGFR, or both. However, of the 11 protein biomarkers, none have prognostic value beyond albuminuria and eGFR.

Urinary Kidney Biomarker Panel Detects Preclinical Antisense Oligonucleotide-Induced Tubular Toxicity

Sensitive kidney safety assessment is important for successful drug development in both preclinical and clinical stages. The Food and Drug Administration recently qualified a composite measure of 6 urine creatinine-normalized biomarkers, such as clusterin, cystatin C, kidney injury molecule 1 (KIM-1), N-acetyl-β-d-glucosaminidase, neutrophil gelatinase-associated lipocalin (NGAL), and osteopontin, for monitoring kidney toxicity in early clinical trials. The qualification was based on small molecule drugs in humans, and the full panel has not been assessed in other species or for other drug modalities. This study evaluated the effects on these biomarkers for a constrained ethyl antisense oligonucleotide (tool ASO) with demonstrated kidney toxicity in mice compared to a control ASO of the same chemistry. Dosing 50 mg/kg of the tool ASO resulted in mild proximal tubular pathology and elevations in KIM-1, clusterin, NGAL, and cystatin C. A lower dose resulted in milder histopathology and lower biomarker increases. Unexpectedly, the control ASO induced mild elevations in KIM-1, NGAL, and cystatin C, despite the lack of pathology. Both KIM-1 and clusterin were most closely associated with kidney pathology and increased with the severity of injury. Altogether, our data suggest that a biomarker panel is a sensitive tool for the detection of preclinical ASO-induced kidney pathology.

The title: serum neutrophil Gelatinase-associated Lipocalin at 3 hours after return of spontaneous circulation in patients with cardiac arrest and therapeutic hypothermia: early predictor of acute kidney injury

Background

Serum neutrophil gelatinase-associated lipocalin (NGAL) could be used as a predictive marker of acute kidney injury (AKI) in patients with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA) who are managed with targeted temperature management (TTM). However, the NGAL measurement timepoints vary from immediately after ROSC to several days later. The primary objective of this study was to determine an association between AKI and NGAL, both immediately (ROSC-NGAL) and 3 h after ROSC (3 h-NGAL), in OHCA patients with TTM. The secondary objective was to ascertain the association between NGAL levels in the early post-ROSC phase and the neurologic outcomes at discharge.

Methods

This prospective observational study was conducted between January 2016 and December 2018 and enrolled adult OHCA patients (≥18 years) with TTM after ROSC. The serum NGAL level was measured both immediately and 3 h after ROSC. Univariate and multivariate analyses were performed to identify the associations between AKI, poor neurologic outcome, and NGAL.

Results

Among 861 OHCA patients, 89 patients were enrolled. AKI occurred in 48 (55.1%) patients. On multivariate logistic regression analysis, 3 h-NGAL was significantly associated with AKI (odds ratio [OR] 1.022; 95% confidence interval [CI] 1.009–1.035; p = 0.001). The area under the receiver operating characteristic curve of 3 h-NGAL for AKI was 0.910 (95% CI 0.830–0.960), and a cut-off value of 178 ng/mL was identified. Both ROSC-NGAL and 3 h-NGAL were not significantly associated with poor neurologic outcome on multivariate logistic regression analysis (ROSC-NGAL; OR 1.017; 95% CI 0.998–1.036; p = 0.084, 3 h-NGAL; OR 0.997; 95% CI 0.992–1.001; p = 0.113).

Conclusions

The serum NGAL concentration measured 3 h after ROSC is an excellent early predictive marker for AKI in OHCA patients treated with TTM. Future research is needed to identify the optimal measurement timepoint to establish NGAL as a predictor of neurologic outcome and to validate the findings of this research.

Postangiography Increases in Serum Creatinine and Biomarkers of Injury and Repair

BACKGROUND AND OBJECTIVES

It is unknown whether iodinated contrast causes kidney parenchymal damage. Biomarkers that are more specific to nephron injury than serum creatinine may provide insight into whether contrast-associated AKI reflects tubular damage. We assessed the association between biomarker changes after contrast angiography with contrast-associated AKI and 90-day major adverse kidney events and death.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a longitudinal analysis of participants from the biomarker substudy of the Prevention of Serious Adverse Events following Angiography trial. We measured injury (kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, IL-18) and repair (monocyte chemoattractant protein-1, uromodulin, YKL-40) proteins from plasma and urine samples at baseline and 2-4 hours postangiography. We assessed the associations between absolute changes and relative ratios of biomarkers with contrast-associated AKI and 90-day major adverse kidney events and death.

RESULTS

Participants (n=922) were predominately men (97%) with diabetes (82%). Mean age was 70±8 years, and eGFR was 48±13 ml/min per 1.73 m²; 73 (8%) and 60 (7%) participants experienced contrast-associated AKI and 90-day major adverse kidney events and death, respectively. No postangiography urine biomarkers were associated with contrast-associated AKI. Postangiography plasma kidney injury molecule-1 and IL-18 were significantly higher in participants with contrast-associated AKI compared with those who did not develop contrast-associated AKI: 428 (248, 745) versus 306 (179, 567) mg/dl; P=0.04 and 325 (247, 422) versus 280 (212, 366) mg/dl; P=0.009, respectively. The majority of patients did not experience an increase in urine or plasma biomarkers. Absolute changes in plasma IL-18 were comparable in participants with contrast-associated AKI (-30 [-71, -9] mg/dl) and those without contrast-associated AKI (-27 [-53, -10] mg/dl; P=0.62). Relative ratios of plasma IL-18 were also comparable in participants with contrast-associated AKI (0.91; 0.86, 0.97) and those without contrast-associated AKI (0.91; 0.85, 0.96; P=0.54).

CONCLUSIONS

The lack of significant differences in the absolute changes and relative ratios of injury and repair biomarkers by contrast-associated AKI status suggests that the majority of mild contrast-associated AKI cases may be driven by hemodynamic changes at the kidney.

The role of specific biomarkers, as predictors of post-operative complications following flexible ureterorenoscopy (FURS), for the treatment of kidney stones: a single-centre observational clinical pilot-study in 37 patients

BACKGROUND

The number of patients diagnosed and subsequently treated for kidney stones is increasing, and as such the number of post-operative complications is likely to increase. At present, little is known about the role of specific biomarkers, following flexible ureterorenoscopy (FURS) for the surgical treatment of kidney stones. The main aim of the study was to evaluate the role of kidney and infection biomarkers, in patients undergoing FURS.

METHODS

Included were 37 patients (24 males, 13 females), who underwent elective FURS, for the treatment of kidney stones. Venous blood samples were collected from each patient: pre-operatively, and at 30 min, 2 and 4 h post-operatively. Changes to kidney (NGAL, Cystatin-C) and infection (MPO, PCT) biomarkers was quantified by means of ELISA, Biomerieux mini-vidas and Konelab 20 analysers.

RESULTS

Four patients developed post-operative complications (3 - UTIs with urinary retention, 1 - urosepsis. NGAL concentration increased significantly following FURS (p = 0.034). Although no significant changes were seen in Cystatin C, MPO and PCT (p ≥ 0.05) some key clinical observation were noted. Limiting factors for this study were the small number of patients recruited and restriction in blood sampling beyond 4 h.

CONCLUSIONS

Although not confirmative, changes seen to biomarkers such as Cystatin C, NGAL and MPO in our observational clinical pilot-study may warrant further investigation, involving larger cohorts, to fully understand the role of these biomarkers and their potential association with post-operative complications which can develop following FURS.

Molecular Mechanisms of AKI in the Elderly: From Animal Models to Therapeutic Intervention

Acute kidney injury (AKI), a critical syndrome characterized by a sudden reduction of renal function, is a common disorder among elderly patients particularly in Intensive Care Unit (ICU). AKI is closely associated with both short- and long-term mortality and length of hospital stay and is considered a predictor of chronic kidney disease (CKD). Specific hemodynamic, metabolic, and molecular changes lead to increased susceptibility to injury in the aged kidney; therefore, certain causes of AKI such as the prerenal reduction in renal perfusion or vascular obstructive conditions are more common in the elderly; moreover, AKI is often multifactorial and iatrogenic. Older patients present several comorbidities (diabetes, hypertension, heart failure) and are exposed to multiple medical interventions such as the use of nephrotoxic contrasts media and medications, which can also trigger AKI. Considering the emerging relevance of this condition, prevention and treatment of AKI in the elderly should be crucial in the internist and emergency setting. This review article summarizes the incidence, the risk factors, the pathophysiology, the molecular mechanisms and the strategies of prevention and treatment of AKI in elderly patients.

Real-Time Monitoring of a Protein Biomarker

The ability to monitor protein biomarkers continuously and in real-time would significantly advance the precision of medicine. Current protein-detection techniques, however, including ELISA and lateral flow assays, provide only time-delayed, single-time-point measurements, limiting their ability to guide prompt responses to rapidly evolving, life-threatening conditions. In response, here we present an electrochemical aptamer-based sensor (EAB) that supports high-frequency, real-time biomarker measurements. Specifically, we have developed an electrochemical, aptamer-based (EAB) sensor against Neutrophil Gelatinase-Associated Lipocalin (NGAL), a protein that, if present in urine at levels above a threshold value, is indicative of acute renal/kidney injury (AKI). When deployed inside a urinary catheter, the resulting reagentless, wash-free sensor supports real-time, high-frequency monitoring of clinically relevant NGAL concentrations over the course of hours. By providing an "early warning system", the ability to measure levels of diagnostically relevant proteins such as NGAL in real-time could fundamentally change how we detect, monitor, and treat many important diseases.

Biomarkers of Acute and Chronic Kidney Disease

The current unidimensional paradigm of kidney disease detection is incompatible with the complexity and heterogeneity of renal pathology. The diagnosis of kidney disease has largely focused on glomerular filtration, while assessment of kidney tubular health has notably been absent. Following insult, the kidney tubular cells undergo a cascade of cellular responses that result in the production and accumulation of low-molecular-weight proteins in the urine and systemic circulation. Modern advancements in molecular analysis and proteomics have allowed the identification and quantification of these proteins as biomarkers for assessing and characterizing kidney diseases. In this review, we highlight promising biomarkers of kidney tubular health that have strong underpinnings in the pathophysiology of kidney disease. These biomarkers have been applied to various specific clinical settings from the spectrum of acute to chronic kidney diseases, demonstrating the potential to improve patient care.

Perioperative acute kidney injury: Stratification and risk reduction strategies

Perioperative acute kidney injury (AKI) is associated with increased morbidity and mortality. Patient comorbidities, the type of surgery, timing of surgery, and exposure to nephrotoxins are important contributors for developing acute kidney injury. Urgent or emergent surgery, cardiac, and organ transplantation procedures are associated with a higher risk of acute kidney injury. Nephrotoxic drugs, contrast dye, and diuretics can worsen preexisting kidney dysfunction or act as an additive and/or synergistic insult to perioperative injury. A history of preoperative chronic kidney disease is the main risk factor for developing AKI, conferring as much as a 10-fold risk. However, beyond the preoperative renal function, the development of AKI is a complex phenomenon that involves a combination of patient-related and surgery-related factors.

SHORT TERM EFFECT OF LAPAROSCOPIC SLEEVE GASTRECTOMY ON CLINICAL, RENAL PARAMETERS AND URINARY NGAL LEVELS IN DIABETIC AND NON DIABETIC OBESITY

Background

Although diseases such as diabetes, hypertension, obstructive sleep apnea and hyperlipidemia are clearly documented as obesity associated diseases, it is not well-known whether obesity causes renal pathologies. The aim of the present study was to evaluate the effect of weight loss following laparoscopic sleeve gastrectomy on clinical, renal parameters and urinary Neutrophil gelatinase-associated lipocalin (NGAL) levels in diabetic and non-diabetic obese patients.

Methods

Nineteen morbidly obese patients (10 diabetic and 9 non diabetic) who underwent laparoscopic sleeve gastrectomy were evaluated clinically (anthropometric measurements) and biochemically before surgery and at 6 months from surgery.

Results

Significant decreases in weight, BMI, FPG, PPG and HbA1c levels were observed in the diabetic group when the baseline and 6th month parameters of the patients were compared. There was also a significant decrease in SBP and DBP. At 6^th month following laparoscopic sleeve gastrectomy, renal parameters such as creatinine, mAlb/creatinine, NGAL/creatinine did not differ in the diabetic group. In the nondiabetic group, serum creatinine levels were significantly decreased, but other renal parameters such as mAlb/creatinine and NGAL/creatinine were not significantly different.

Conclusions

Our findings revealed significant decreases in weight, body mass index and glycemic parameters after sleeve gastrectomy in diabetic and non-diabetic patients, while no significant alteration was noted in renal functions, urinary NGAL and microalbumin levels.

Non-invasive urinary biomarkers of renal function in sickle cell disease: an overview

Sickle cell disease (SCD) is a hereditary condition characterized by homozygosis of the hemoglobin S (HbS) gene. Marked morbimortality is observed due to chronic hemolysis, endothelial injury, and episodes of vaso-occlusion, which leads to multi-organ damage. Renal impairment is common and may have different presentations, such as deficiency in urinary acidification or concentration, glomerulopathies, proteinuria, and hematuria, frequently resulting in end-stage renal disease (ESRD). Novel biomarkers of renal function, such as kidney injury molecule 1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) and monocyte chemoattractant protein 1 (MCP-1) are being studied in order to enable early diagnosis of kidney damage in SCD.

A study of the utility of novel non-invasive urinary and serum biomarkers of blunt kidney injury in a rat model: NGAL, KIM-1, and IL-18

This study investigated changes in the concentrations of serum and urine neutrophil gelatinase lipocalin (NGAL), kidney injury molecule 1 (KIM-1), interleukin 18 (IL-18), and cystatin-C (Cys-C) induced by parenchymal and tubular damage following blunt kidney trauma, as well as their potential utility as biomarkers in the detection and follow-up of patients with suspected blunt renal trauma. Three-month-old male Sprague-Dawley rats (n = 18) were divided into three groups (n = 6 in each): group 1: control group (no intervention); group 2: sham group (explorative surgery and exposure of the left kidneys); and group 3: trauma group (explorative surgery and induction of blunt renal trauma of the left kidneys). Serum and urine samples were collected before and 12-24, 36-48, and 60-72 hours later for NGAL, KIM-1, IL-18, and Cys-C measurements. In the trauma group, there was a statistically significant increase in post-operative NGAL, KIM-1, and IL-18 values after 12-24 h and 36-48 h, as compared with pre-operative values. There was also a statistically significant increase in post-operative serum and urine Cys-C values after 60-72 h, as compared with pre-operative values. NGAL, KIM-1, and IL-18 may represent novel non-invasive descriptive candidate biomarkers of early-stage tubular damage in children with renal trauma.

Early Diagnosis and Prognostic Value of Acute Kidney Injury in Critically Ill Patients

Background and objectives: In hospitalized children, acute kidney injury (AKI) remains to be a frequent and serious condition, associated with increased patient mortality and morbidity. Identifying early biomarkers of AKI and patient groups at the risk of developing AKI is of crucial importance in current clinical practice. Specific human protein urinary neutrophil gelatinase-associated lipocalin (uNGAL) and interleukin 18 (uIL-18) levels have been reported to peak specifically at the early stages of AKI before a rise in serum creatinine (sCr). Therefore, the aim of our study was to determine changes in uNGAL and uIL-18 levels among critically ill children and to identify the patient groups at the highest risk of developing AKI. Materials and methods: This single-center prospective observational study included 107 critically ill children aged from 1 month to 18 years, who were treated in the Pediatric Intensive Care Unit (PICU) of Lithuanian University of Health Sciences Hospital Kauno Klinikos from 1 December 2013, to 30 November 2016. The patients were divided into two groups: those who did not develop AKI (Group 1) and those who developed AKI (Group 2). Results: A total of 68 (63.6%) boys and 39 (36.4%) girls were enrolled in the study. The mean age of the patients was 101.30 ± 75.90 months. The mean length of stay in PICU and hospital was 7.91 ± 11.07 and 31.29 ± 39.09 days, respectively. A total of 32 (29.9%) children developed AKI. Of them, 29 (90.6%) cases of AKI were documented within the first three days from admission to hospital. In all cases, AKI was caused by diseases of non-renal origin. There was a significant association between the uNGAL level and AKI between Groups 1 and 2 both on day 1 (p = 0.04) and day 3 (p = 0.018). Differences in uNGAL normalized to creatinine in the urine (uCr) (uNGAL/uCr) between the groups on days 1 and 3 were also statistically significant (p = 0.007 and p = 0.015, respectively). uNGAL was found to be a good prognostic marker. No significant associations between uIL-18 or Uil-18/uCr and development of AKI were found. However, the uIL-18 level of >69.24 pg/mL during the first 24 h was associated with an eightfold greater risk of AKI progression (OR = 8.33, 95% CI = 1.39–49.87, p = 0.023). The AUC for uIL-18 was 73.4% with a sensitivity of 62.59% and a specificity of 83.3%. Age of <20 months, Pediatric Index of Mortality 2 (PIM2) score of >2.5% on admission to the PICU, multiple organ dysfunction syndrome with dysfunction of three and more organ systems, PICU length of stay more than three days, and length of mechanical ventilation of >five days were associated with a greater risk of developing AKI. Conclusions: Significant risk factors for AKI were age of <20 months, PIM2 score of >2.5% on admission to the PICU, multiple organ dysfunction syndrome with dysfunction of 3 and more organ systems, PICU length of stay of more than three days, and length of mechanical ventilation of > five days. uNGAL was identified as a good prognostic marker of AKI. On admission to PICU, uNGAL should be measured within the first three days in patients at the risk of developing AKI. The uIL-18 level on the first day was found to be as a biomarker predicting the progression of AKI.

Urinary neutrophil gelatinase-associated lipocalin in dogs with stable or progressive kidney disease

BACKGROUND

Active kidney injury may play a role in chronic kidney disease (CKD) progression in dogs. Neutrophil gelatinase-associated lipocalin (NGAL), a novel tubular kidney injury biomarker, may help differentiate progressive CKD from stable CKD in dogs.

OBJECTIVES

To determine if urinary NGAL : creatinine ratio (UNCR) differentiates stable and progressive CKD in dogs. We hypothesized that UNCR would be higher in dogs with progressive CKD versus stable CKD.

ANIMALS

Twenty-one healthy control dogs, 22 with prerenal azotemia, 19 with stable CKD, 30 with progressive CKD, and 27 with acute kidney injury (AKI).

METHODS

Prospective study. Azotemic (serum creatinine concentration >1.6 mg/dL) dogs or nonazotemic AKI dogs were enrolled and classified into 4 groups: (1) prerenal azotemia, (2) stable CKD, (3) progressive CKD, and (4) AKI. Urinary NGAL was measured by ELISA and UNCR compared among groups. Urine protein : creatinine ratio (UPC) in dogs with stable and progressive CKD was compared to UNCR for differentiating CKD groups.

RESULTS

UNCR was significantly higher in dogs with progressive CKD than stable CKD. UNCR of the prerenal azotemia group was significantly lower than that of the progressive CKD and AKI groups. No significant difference was found in UNCR between stable CKD and prerenal azotemia groups. ROC curve analysis of UNCR for differentiating progressive CKD from stable CKD resulted in an AUC of 0.816 (95% confidence interval [CI], 0.673-0.959), greater than that of UPC (0.696; 95% CI, 0.529-0.863).

CONCLUSIONS AND CLINICAL IMPORTANCE

Urinary NGAL could be helpful to predict the risk of progression in dogs with CKD.

Biomarkers in Routine Heart Failure Clinical Care

Heart failure is a clinical condition with complex pathophysiology that involves many different processes. Diagnosis is often difficult in patients presenting for the first time with breathlessness. Many biomarkers have been identified that are elevated in heart failure and their role in assessing prognosis has also been investigated. However, at present the natriuretic peptides appear to be the gold standard biomarker against which the other biomarkers are compared. In this review we will examine the evidence behind the other biomarkers for use in heart failure patients and the current guidelines for their use.

The renoprotective effect of concomitant fosfomycin in the treatment of pulmonary exacerbations in cystic fibrosis

Background

Fosfomycin, effective in Cystic Fibrosis (CF), competes with aminoglycosides at renal binding sites and may therefore afford a renoprotective effect when used in combination therapy. We explored this by using markers of acute renal tubular damage [N-acetyl-β-d-glucose-aminidase (NAG), alanine amino-peptidase (AAP) and β₂-microglobulin].

Methods

Using a prospective randomized crossover trial design, at an acute pulmonary exacerbation, 18 adult CF patients received either 14 days of intravenous (IV) tobramycin or IV tobramycin and IV fosfomycin, both in combination with a second IV antibiotic (colomycin).

Results

Urinary NAG (P = 0.003) and AAP (P = 0.03) following treatment with concomitant fosfomycin were lower than those after treatment with tobramycin and colomycin alone. Fosfomycin attenuated the total 24-h urinary protein leak (P = 0.0001). The 14-day improvements in all surrogate markers of exacerbation resolution (FEV₁% predicted, FVC, white cell count and C-reactive protein) were similar for both treatment regimens.

Conclusion

The addition of fosfomycin reduces acute renal injury caused by IV aminoglycoside therapy in CF pulmonary exacerbations.

Utility of neutrophil gelatinase-associated lipocalin in the management of acute kidney injury: A prospective, observational study

Background:

Utilization of renal biomarkers such as neutrophil gelatinase-associated lipocalin in the management of acute kidney injury may be useful as a diagnostic tool in the emergency department.

Objective:

The aim of this study is to determine the relationship between serum neutrophil gelatinase-associated lipocalin level and the severity of the acute kidney injury based on the Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) classification, and to investigate the role of the serum neutrophil gelatinase-associated lipocalin level in differentiating the etiology and predicting the 30-day mortality rate and need for dialysis.

Methods:

This prospective, observational study was conducted from March 2015 to 2016. Adult patients with acute kidney injury in the emergency department were enrolled in the study. Demographic and clinical features such as hypovolemic state, nephrotoxic substance exposure, renal functions, and serum neutrophil gelatinase-associated lipocalin level were evaluated. After the etiology of the acute kidney injury was ascertained, the severity of the acute kidney injury was determined according to RIFLE criteria. Primary outcome was defined as the correlation between serum neutrophil gelatinase-associated lipocalin level and the severity of the acute kidney injury according to RIFLE classification. Secondary outcomes were defined as the relationship between the serum neutrophil gelatinase-associated lipocalin level and the etiology of the acute kidney injury; need for dialysis and 30-day mortality were defined as poor outcomes.

Results:

A total of 87 patients were included in the study. Mean serum neutrophil gelatinase-associated lipocalin levels were 380.14 ± 276.65 ng/mL in RIFLE-R, 425.80 ± 278.99 ng/mL in RIFLE-I, and 403.60 ± 293.15 ng/mL in RIFLE-F groups. There was no statistically significant relationship between the severity of acute kidney injuries and serum neutrophil gelatinase-associated lipocalin level. Initial serum neutrophil gelatinase-associated lipocalin levels in the emergency department did not indicate a statistically significant ability to predict the etiology of acute kidney injury, 30-day mortality rates, or need for dialysis.

Conclusion:

Initial serum neutrophil gelatinase-associated lipocalin level in the emergency department is not a determinant tool for predicting the severity, etiology, 30-day mortality rates, or need for dialysis in cases of acute kidney injuries.

Evaluation value of neutrophil gelatinase-associated lipocalin for the renal dysfunction of patients with chronic kidney disease: A meta-analysis

OBJECTIVE

The role of neutrophil gelatinase-associated lipocalin (NGAL) for the evaluation of renal function in chronic kidney disease (CKD) has not yet to be determined. We aimed to perform a meta-analysis exploring the correlation between NGAL and glomerular filtration rate (GFR) in CKD patients, and to further identify factors affecting NGAL's performance.

METHODS

Studies dated before November 2017 were retrieved from PubMed, Embase, Web of Science, and the Cochrane Library. A total of 28 relevant studies (involving 3082 patients from 17 countries) were included. The second version of the Quality Assessment for Studies of Diagnostic Accuracy demonstrated that no significant bias had influenced the methodological quality of the included studies.

RESULTS

Neutrophil gelatinase-associated lipocalin showed a strong negative correlation with measured glomerular filtration rate (mGFR). The pooled correlation coefficient (r) with corresponding 95% confidence intervals for the correlation between serum NGAL (sNGAL) and GFR was -0.48, meanwhile that for urine NGAL (uNGAL) and GFR was -0.34. However, NGAL's performance is different in subgroups restricted by clinical settings, race, sex, age, and staging of renal function.

CONCLUSION

Neutrophil gelatinase-associated lipocalin could be a renal function evaluation marker for patients with renal dysfunction in CKD. Compared with uNGAL, there was a significant negative correlation between sNGAL and GFR. The performances of sNGAL and uNGAL were restricted by clinical factors that should be considered in regards to the sampling source selection.

Visceral leishmaniasis-associated nephropathy in hospitalised Brazilian patients: new insights based on kidney injury biomarkers

OBJECTIVE

To evaluate the usefulness of early acute kidney injury (AKI) biomarkers in clinical management of visceral leishmaniasis.

METHODS

Prospective study with 50 hospitalised VL patients. AKI biomarkers, that is, serum and urinary neutrophil gelatinase-associated lipocalin (sNGAL, uNGAL, respectively), urinary kidney injury molecule-1 (uKIM-1) and urinary monocyte chemotactic protein-1 (uMCP-1), were quantified by immunoassay (ELISA). Also, interferon-gamma (INF-y) and C-reactive protein (CRP) were evaluated as inflammatory biomarkers possibly related to VL severity.

RESULTS

VL patients had hyponatremia, hypoalbuminemia, hypergammaglobulinemia, haematologic and hepatic disorders. AKI was found in 46%, and one death (2%) occurred. The AKI group had significant longer hospital stay, lower levels of IFN-y and higher levels of CRP, more clinical renal abnormalities and higher levels of sNGAL, uNGAL, uKIM-1 and uMCP-1. Overall, sNGAL, uKIM-1 and uMCP-1 showed correlations with important clinical renal abnormalities, such as proteinuria, albuminuria, serum creatinine and glomerular filtration rate using adjusted correlations with CRP and IFN-y. Only sNGAL showed an early association with AKI development (OR = 2.78, 95% CI = 1.429-5.428, per each increase of 50 ng/ml), even after adjusting for clinical signals of VL severity and for immune biomarkers. Moreover, sNGAL showed a better performance in predicting AKI development (AUC-ROC = 0.81, 95% CI = 0.69-0.93; cut-off = 154 ng/ml, sensitivity = 82.6%, specificity = 74.1%, P < 0.001).

CONCLUSIONS

Visceral leishmaniasis-associated nephropathy showed important proximal tubular injury and glomerular inflammation. Serum NGAL showed an early association with VL-associated nephropathy and may be used to improve clinical management strategies and decrease morbimortality in VL patients.

Comparative proteomics of respiratory exosomes in cystic fibrosis, primary ciliary dyskinesia and asthma

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are pulmonary genetic disorders associated with inflammation and heterogeneous progression of the lung disease. We hypothesized that respiratory exosomes, nanovesicles circulating in the respiratory tract, may be involved in the progression of inflammation-related lung damage. We compared proteomic content of respiratory exosomes isolated from bronchoalveolar lavage fluid in CF and PCD to asthma (A), a condition also associated with inflammation but with less severe lung damage. BALF were obtained from 3 CF, 3 PCD and 6 A patients. Exosomes were isolated from BALF by ultracentrifugations and characterized using immunoelectron microscopy and western-blot. Exosomal protein analysis was performed by high-resolution mass spectrometry using label-free quantification. Exosome enrichment was validated by electron microscopy and immunodetection of CD9, CD63 and ALIX. Mass spectrometry analysis allowed the quantification of 665 proteins, of which 14 were statistically differential according to the disease. PCD and CF exosomes contained higher levels of antioxidant proteins (Superoxide-dismutase, Glutathione peroxidase-3, Peroxiredoxin-5) and proteins involved in leukocyte chemotaxis. All these proteins are known activators of the NF-KappaB pathway. Our results suggest that respiratory exosomes are involved in the pro-inflammatory propagation during the extension of CF or PCD lung diseases.

SIGNIFICANCE

The mechanism of local propagation of lung disease in cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) is not clearly understood. Differential Proteomic profiles of exosomes isolated from BAL from CF, PCD and asthmatic patients suggest that they carry pro-inflammatory proteins that may be involved in the progression of lung damage.

Evaluation of serum neutrophil gelatinase-associated lipocalin as a novel biomarker of cardiorenal syndrome in dogs

Worsening renal function and azotemia in patients with heart failure (HF) are strongly associated with disease severity and poor prognosis. Increasing interest in this correlation led to the description and classification of cardiorenal syndrome (CRS). We evaluated the role of neutrophil gelatinase-associated lipocalin (NGAL) in the early detection of CRS in dogs with HF. Ten healthy dogs and 31 dogs admitted with HF were included in our study. NGAL and troponin-I were measured on samples collected on the day of admission; creatinine was measured on admission and again on day 7. The CRS group was defined as subsequently developing renal azotemia. Of 31 dogs with HF, 20 were included in the HF group, and 11 were included in the CRS group. The admission NGAL concentrations of the CRS group were significantly higher than those of other groups ( p < 0.001). The severity of HF evaluation based on the modified New York Heart Association classification showed significant correlation with NGAL ( p < 0.001) and troponin-I ( p = 0.009) concentration. However, only serum NGAL concentration at admission was significantly associated with the development of CRS in dogs with HF ( p = 0.021). The admission serum NGAL ≥ 16.0 ng/mL (optimal cutoff value) had a sensitivity of 90.9% and specificity of 90.0% in predicting the development of CRS.

Urinary Biomarkers to Predict Neonatal Acute Kidney Injury: A Review of the Science

Acute kidney injury (AKI) occurs in approximately 30% of all infants hospitalized in the neonatal intensive care unit. About 40% of very low-birth-weight infants develop AKI, with an estimated mortality rate of 50% to 80%. Very low-birth-weight survivors have twice the risk of developing chronic renal disease later in life compared with their term counterparts. Current diagnostic modalities for AKI include serum creatinine and urine output; however, recent studies suggest that these measures are imprecise, as they may not change until 25% to 50% of renal function is lost. Urinary biomarkers may more accurately identify infants at risk for early AKI development. The purpose of this review is to discuss current research findings related to neonatal AKI risk factors, provide an overview of short- and long-term outcomes, describe innovative diagnostic approaches, and identify future research direction needed to improve prediction and intervention strategies associated with renal impairment.

Predictive ability of urinary biomarkers for outcome in children with acute kidney injury

BACKGROUND

Urinary neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-beta-D-glucosaminidase (NAG), and interleukin 18 (IL-18) were found to be useful for early detection of acute kidney injury (AKI). The objective of this study was to determine the predictive ability of biomarkers for mortality and variation in levels in relation to different stages of AKI, need for dialysis, etiologies, and with duration of hospital stay.

METHODS

Urinary NGAL, NAG, and IL-18 levels were measured in 50 children with AKI and 30 age- and gender-matched healthy controls. AKI was classified as per pediatric Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria.

RESULTS

Median NGAL, NAG, and IL-18 values were significantly increased in AKI patients compared with controls (p < 0.001), with significant increase among risk, injury, and failure stages. Nonsurvivors had significantly higher median levels of NGAL (p = 0.008) and NAG (p = 0.018) than survivors. NGAL had highest area under the curve (AUC) at 0.750 [confidence interval (CI) 0.580-0.920], followed by NAG at 0.724 (CI 0.541-0.907), with sensitivity and specificity of 75 % each; and IL-18 (AUC 0.688, CI 0.511-0.864), with sensitivity 62.5 % and specificity 70.8 %, for predicting mortality. Values were significantly higher in patients who required peritoneal dialysis (PD) than in those in whom it was not indicated. Levels were comparable among different etiologies. Only NGAL level was found to be a significant risk factor associated with longer duration of hospital stay.

CONCLUSIONS

Urinary NGAL and NAG had modest predictive ability for mortality. Children requiring dialysis had significantly raised levels, and the NGAL level had significant association with duration of hospital stay.

Neutrophil Gelatinase-Associated Lipocalin as a Marker for Renal Dysfunction Detection in Critically Ill Patients with Increased Intraabdominal Pressure

Introduction

Elevated intraabdominal pressure (IAP) it is known to have an impact on renal function trough the pressure transmitted from the abdominal cavity to the vasculature responsible for the renal blood flow. Intraabdominal pressure is found to be frequent in intensive care patients and also to be a predictor of mortality. Intra-abdominal high pressure is an entity that can have serious impact on intensive care admitted patients, studies concluding that if this condition progresses to abdominal compartment syndrome mortality is as high as 80%.

Aim

The aim of this study was to observe if a link between increased intraabdominal pressure and modification in renal function exists (NGAL, creatinine clearance).

Material and Method

The study enrolled 30 critically ill patients admitted in the Intensive Care Unit of SCJU TîrguMures between November 2015 and August 2016. The study enrolled adult, hemodynamically stable patients admitted in intensive critical care - defined by a normal blood pressure maintained without any vasopressor or inotropic support, invasive monitoring using PICCO device and abdominal pressure monitoring.

Results

The patients were divided into two groups based on the intraabdominal pressure values: normal intraabdominal pressure group= 52 values and increased intraabdominal group= 35 values. We compared the groups in the light of NGAL values, 24 hours diuresis, GFR and creatinine clearance. The groups are significantly different when compared in the light of NGAL values and GFR values. We obtained a statistically significant correlation between NGAL value and 24 hour diuresis. No other significant correlations were encountered between the studied items.

Conclusions

NGAL values are increased in patients with high intraabdominal pressure which may suggest its utility as a cut off marker for patients with increased intraabdominal pressure. There is a significant decreased GFR in patient with elevated intraabdominal pressure, observation which can help in early detection of renal injury in patients due to high intraabdominal pressure. No correlation was found between creatinine clearance and increased intraabdominal pressure.

Role of Urinary Neutrophil Gelatinase-associated Lipocalin as a Biomarker of Acute Kidney Injury in Patients with Circulatory Shock

Background

The early prediction of acute kidney injury (AKI) by the current clinical and laboratory methods remains inadequate. Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a promising noninvasive biomarker of kidney injury in shock. The aim of this study was to assess the ability of urinary NGAL (uNGAL) to predict AKI in adult Intensive Care Unit (ICU) patients.

Materials and Methods

We prospectively studied 70 patients with circulatory shock admitted to the ICU over a period of 1 year. uNGAL was analyzed at ICU admission and after 24 h. Risk, injury, failure, loss, and end-stage kidney criteria were calculated at admission and for consecutive 4 days. The primary outcome was AKI defined as an increase in creatinine of at least 50% from baseline or a reduction in urine output to <0.5 ml/kg/h for 6 h.

Results

uNGAL was a good diagnostic marker for AKI development; at day 1, the cutoff value 48.54 ng/mL had a sensitivity and specificity of 79.49 and 73.14, respectively, and the area under the curve (AUC) of 0.82 (95% confidence interval [CI], 0.75-0.87) for predicting AKI. At day 2, the cutoff value 190.92 ng/mL had a sensitivity and specificity of 90.0 and 64.66, respectively, and the AUC of 0.76 (95% CI, 0.70-0.88) for predicting AKI.

Conclusion

uNGAL could be a good early predictor biomarker of AKI following circulatory shock.

Dynamic Changes of Plasma Neutrophil Gelatinase-Associated Lipocalin Predicted Mortality in Critically Ill Patients with Systemic Inflammatory Response Syndrome

Background and Aims:

About 50% of patients admitted to the Intensive Care Unit have systemic inflammatory response syndrome (SIRS), and about 10%–20% of them died. Early risk stratification is important to reduce mortality. Plasma neutrophil gelatinase-associated lipocalin (NGAL) is increased by inflammation and infection. Its ability to predict mortality in SIRS patients is of interest. We evaluated the ability of serial measurement of NGAL for the prediction of mortality in critically ill patients with SIRS.

Materials and Methods:

This is a secondary analysis of a single-center, prospective, observational study. Patients who fulfill the SIRS criteria were recruited in the study. Delta NGAL at 24 and 48 h (ΔNGAL-24 and ΔNGAL-48) was defined as 24 and 48 h NGAL minus day 1 NGAL; NGAL clearance (NGALc) was defined as percentage of ΔNGAL over day 1 NGAL. The primary outcome of the study is in-hospital mortality.

Results:

A total of 151 patients were analyzed, of which 53 (35%) died. Nonsurvivors were older (51 vs. 45, P = 0.03) and had higher Sequential Organ Failure Assessment (9 ± 7 vs. 7 ± 4, P = 0.02) and Simplified Acute Physiology Score II (47 ± 15 vs. 40 ± 15, P = 0.01) scores as compared to survivors. NGAL concentrations over 3 days were higher in nonsurvivors compared to survivors (repeated measures analysis of variance, P = 0.02). Day 1 NGAL, ΔNGAL-24, and NGALc-24 were not independently predictive of mortality. However, day 3 NGAL, ΔNGAL-48, and NGALc-48 were predictive after adjusted for age and severity of illness (odds ratio 9.1 [1.97–41.7]).

Conclusions:

NGAL dynamics over 48 h independently predicted mortality in critically ill patients with SIRS. This could assist clinicians in risk stratification of this group of high-risk patients.

Diallyl disulfide attenuates acetaminophen-induced renal injury in rats

This study investigated the protective effects of diallyl disulfide (DADS) against acetaminophen (AAP)-induced acute renal injury in male rats. We also investigated the effects of DADS on kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), which are novel biomarkers of nephrotoxicity in renal tissues, in response to AAP treatment. The following four experimental groups were evaluated: (1) vehicle control, (2) AAP (1,000 mg/kg), (3) AAP&DADS, and (4) DADS (50 mg/kg/day). AAP treatment caused acute kidney injury evidenced by increased serum blood urea nitrogen (BUN) levels and histopathological alterations. Additionally, Western blot and immunohistochemistry analysis showed increased expression of KIM-1 and NGAL proteins in renal tissues of AAP-treated rats. In contrast, DADS pretreatment significantly attenuated the AAP-induced nephrotoxic effects, including serum BUN level and expression of KIM-1 and NGAL proteins. Histopathological studies confirmed the renoprotective effect of DADS. The results suggest that DADS prevents AAP-induced acute nephrotoxicity, and that KIM-1 and NGAL may be useful biomarkers for the detection and monitoring of acute kidney injury associated with AAP exposure.

Predicting Severity of Acute Kidney Injury in Term Neonates with Perinatal Asphyxia Using Urinary Neutrophil Gelatinase Associated Lipocalin

OBJECTIVE

To evaluate the utility of urinary Neutrophil Gelatinase Associated Lipocalin (NGAL) as a biomarker for predicting Acute Kidney Injury (AKI) and its severity among neonates with perinatal asphyxia.

METHODS

This descriptive study included 120 term neonates with perinatal asphyxia. Renal parameters of neonates were monitored and AKI was ascertained as per Acute Kidney Injury Network criteria. Urinary NGAL was estimated and correlated with severity of AKI.

RESULTS

Among the 120 neonates with perinatal asphyxia, 55(46 %) had AKI. The median urinary NGAL level was 165 ng/ml (88.8-245.8) in neonates with AKI compared to 58.97(42.8-74.7) in those without AKI. The median NGAL was 134.45(112.2-162.5), 301.2(255.5-361.2), 416.2(412.2-465.5) in AKI stages 1, 2 and 3 respectively. An NGAL cut off value of 86.82 ng/ml had 87 % sensitivity and 87.7 % specificity in predicting AKI.

CONCLUSIONS

Urinary NGAL is a useful biomarker for predicting AKI and its severity among neonates with perinatal asphyxia.

A comparison of three commercial platforms for urinary NGAL in critically ill adults

BACKGROUND

Early biomarkers for acute kidney injury (AKI) diagnosis are needed since an increase in serum creatinine levels is a late marker. Neutrophil gelatinase-associated lipocalin (NGAL) is one of the most promising AKI biomarkers. Prior to routine clinical use, it is necessary to evaluate and validate a high-throughput commercially available method for NGAL detection. The aim of this study was to do an independent validation and comparison of the analytical performance of three different commercially available urine NGAL (uNGAL) assays.

METHODS

Urine samples (n=110) were obtained from various patient groups with and without AKI. All urine samples were processed using Architect NGAL assay, Siemens Advia® 2400 NGAL test, and Siemens Dimension Vista® NGAL Test™, based on the three different platforms.

RESULTS

Overall, there was good agreement among the three assays: Spearman's rank correlation coefficient between Architect and Vista was 0.989 (95% confidence interval [CI], 0.983-0.993), between Architect and Advia, 0.962 (95% CI, 0.937-0.977), between Vista and Advia 2400, 0.975 (95% CI, 0.961-0.984). We observed a negative bias of Architect compared with the other assays: comparing Architect to Vista, the mean bias was -55.7 ng/mL (95% CI, -74.3 to -37.0 ng/mL); comparing Architect to Advia 2400, the mean bias was -40.9 ng/mL (95% CI, -56.4 to -25.4 ng/nL). The bias is proportional to the concentration of uNGAL and is more pronounced at higher levels, while irrelevant near the tested cutoff levels of 100 and 190 ng/mL. Comparing Vista and Advia 2400, the mean bias was 10.1 ng/mL (95% CI, 1.5-18.8 ng/mL). Intra-assay imprecision was generally acceptable across all assays; coefficient of variation ranged from 0.8% to 5.3%.

CONCLUSIONS

All three methods for uNGAL showed acceptable performance for the tested parameters and are comparable with each other at clinically relevant cutoffs. However, Architect yields lower results than the other two methods, with a bias more pronounced at higher uNGAL concentrations, suggesting additional standardization efforts will likely be necessary to better harmonize the uNGAL methods at various clinically relevant cutoffs.

[Acute kidney injury and tubular biomarkers after hematopoietic stem cell transplantation]

AIM

To determine the value of molecular biomarkers (BMs) associated with tubular epithelial damage in developing and predicting acute kidney injury (AKI) after hematopoietic stem cell transplantation (HSCT).

SUBJECTS AND METHODS

The open-label observational prospective study enrolled 90 patients (46 males and 44 females) who had undergone HSCT. The concentrations of BMs (calbindin, clusterin, interleukin-18 (IL-18), kidney injury molecules-1 (KIM-1), glutathione S-transferase-π (GST-π), and monocyte chemoattractant protein-1 (MCP-1) were measured in urinary samples 7 days before HSCT (week 0) and at weeks 1, 2, 3, 4, and 5. Main clinical parameters were simultaneously monitored. AKI was diagnosed and stratified according to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines.

RESULTS

At weeks 1, 2, 3, 4, and 5 after HSCT, the proportion of AKI cases was 7.8, 8.9, 12.5, 27.3, and 35.9%, respectively. The elevated urinary levels of BMs (above the median) were found to be substantially more common than AKI cases. The urinary excretion of the majority of BMs dramatically increased in the early HSCT period. The median number of simultaneously elevated BMs was 3 (2; 5) during the entire follow-up period. Clusterin, MCP-1 and KIM-1 positively and significantly correlated with serum creatinine at the week following the determination of BMs in the multivariate linear regression models adjusted for other confounders. The higher urinary KIM-1 and/or MCP-1 excretion regardless of other clinical indicators was associated with the higher relative risk (RR) of AKI, which increased by 2.3 times with a rise in one of these indicators and by 3.4 times with a rise in both indicators.

CONCLUSION

Multiple renal toxic effects after HSCT result in a substantial and simultaneous elevation of urinary excretion of BMs for tubular damage. Among the BMs studied, KIM-1 and MCP-1 seem to be the most suitable molecules for assessing the risk of AKI in this cohort of patient within the predictive diagnostic approach.

Kidney injury molecule-1 and neutrophil gelatinase associated lipocalin in normoalbuminuric diabetic children

BACKGROUND

We aimed at evaluating the urinary levels of kidney injury molecule-1 ( KIM-1) and neutrophil gelatinase associated lipocalin (NGAL), and the relationship between these markers and clinical and laboratory variables in normoalbuminuric children with type 1 diabetes (T1D).

METHODS

The study group consisted of 60 (F/M: 28/32) children with T1D with a median age of 13 (min: 7.1-max: 17.9) years and a mean HbA1c of 8.6%. The average period of treatment was 6.8±2.2 years. The control group consisted of 60 healthy children [(F/M: 32/28); median age: 13.6 (min: 6.9-max: 17.9) years].

RESULTS

Urinary KIM-1 and NGAL levels were significantly elevated in the diabetic group (KIM-1: 0.50±0.34 ng/mg-cr; NGAL: 33±31 ng/mg-cr) compared with the nondiabetic control subjects (KIM-1: 0.26±0.25 ng/mg-cr, NGAL 13.3±14.5 ng/mg-cr) (p<0.001). No significant associations were observed between NGAL or KIM-1 and the duration of diabetes and HbA1c levels. NGAL was found to be weakly correlated with KIM-1 (p<0.005, r=0.289).

CONCLUSIONS

NGAL and KIM are high in normoalbuminuric diabetic children before reduction in glomerular filtration rate. High NGAL and KIM-1 levels may indicate early diabetic kidney injury; however, we did not observe any relationship between these markers and diabetic indices. For clinical usefulness of these markers, long-term studies are required.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Esculin improves dyslipidemia, inflammation and renal damage in streptozotocin-induced diabetic rats

Background

Increasing studies have shown that dyslipidemia and inflammatory responses play important roles in the progression of microvascular diabetic complications. Esculin (ES), a coumarin derivative, was extracted from Fraxinus rhynchophylla. The present study was to evaluate the potential effects of ES on lipid metabolism, inflammation responses and renal damage in streptozotocin (STZ)-induced experimental diabetic rats and explore the possible mechanism.

Methods

Diabetic rat model was established by administration high-glucose-fat diet and intraperitoneal injection of STZ 45 mg/kg. ES was administrated to diabetic rats intragastrically at 10, 30 and 90 mg/kg for 10 weeks respectively. The levels of triglycerides (TG), total cholesterol (T-CHO), low density lipoproteins (LDL), and high-density-cholesterol (HDL-C) in serum were measured. IL-1, IL-6, ICAM-1, NO, NAGL, and AGEs level in serum were detected by ELISA assay. The accumulation of AGEs in kidney tissue was examined by immunohistochemistry assay.

Results

The results showed that ES could decrease TG, T-CHO, LDL levels in serum of diabetic rats in a dose dependent manner. ES also decreased IL-1, IL-6, ICAM-1, NO and NGAL levels in serum of diabetic rats in a dose dependent manner. Furthermore, ES at 30 and 90 mg/kg significantly decreased AGEs level in serum and alleviated AGEs accumulation in renal in diabetic rats.

Conclusions

Our findings indicate that ES could improve dyslipidemia, inflammation responses, renal damage in STZ-induced diabetic rats and the possible mechanism might be associated with the inhibition of AGEs formation.

Urinary Neutrophil Gelatinase-Associated Lipocalin to Monitor Lupus Nephritis Disease Activity

BACKGROUND

This study was conducted to determine whether there is an association between urinary neutrophil gelatinase-associated lipocalin (uNGAL) and urinary transforming growth factor-β1 (uTGF-β1) with lupus nephritis (LN) disease activity.

METHODS

Urine samples from 18 LN patients were collected every month for six months then examined for uNGAL, uTGF-β1, and renal domain Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score.

RESULTS

The uNGAL levels were significantly different between active and inactive LN (P < 0.05). uTGF-β1 levels were not different between active and inactive LN (P < 0.05). There was a significant correlation between uNGAL levels and renal domain SLEDAI score (r = 0.417, P < 0.05). There was no correlation between uTGF-β1 levels and renal domain SLEDAI score (r = 0.031, P < 0.05).

CONCLUSION

uNGAL is better than uTGF-β1 for differentiation of active and inactive LN. uNGAL can be considered as a biomarker to monitor LN disease activity.

Urine neutrophil gelatinase-associated lipocalin in asphyxiated neonates: a prospective cohort study

BACKGROUND

Acute kidney injury (AKI) is the most common complication of perinatal asphyxia. Recent research indicates that urine neutrophil gelatinase-associated lipocalin (NGAL) is an early marker for AKI; yet, there is a paucity of data about its use in term neonates with perinatal asphyxia.

METHODS

A prospective cohort study was conducted on 108 term babies in the new-born unit of Pumwani Maternity Hospital and Kenyatta National Hospital. Urine NGAL and serum creatinine were measured in 108 term asphyxiated neonates on days 1 and 3 of life.

RESULTS

One-hundred and eight patients were recruited (male:female 1.4:1). At a cut-off of 250 ng/ml, urine NGAL had an acceptable discriminative capability of predicting AKI (area under the curve 0.724). The sensitivity, specificity, positive and negative predictive value and likelihood ratios were 88, 56, 30, 95%, 2 and 0.2 respectively. Urine NGAL levels were significantly higher in patients with AKI compared with those without AKI. An NGAL level greater than 250 ng/ml on day 1 was significantly associated with severe hypoxic ischaemic encephalopathy (HIE); odds ratio = 8.9 (95% CI 1.78-37.69) and mortality; odds ratio = 8.9 (95% CI 1.78-37.69).

CONCLUSION

Urine NGAL is a good screening test for the early diagnosis of AKI. It is also a predictor of mortality and severity of HIE in asphyxiated neonates.

Neutrophil Gelatinase-Associated Lipocalin: A New Marker of Renal Function in C-Related End Stage Liver Disease

Background/Aims. Renal impairment is a common complication of cirrhosis. Serum creatinine is less sensitive in these patients. Measurement of the glomerular filtration rate (GFR) is the gold standard but time consuming. The aim is to validate plasma NGAL (pNGAL) and urinary NGAL (uNGAL) as markers of renal function in patients with HCV related cirrhosis. Patient and Methods. One hundred HCV related end stage liver cirrhosis patients were randomized into two groups: Group I (n = 35), patients with GFR < 60 mL/m measured by isotope scanning of the kidney (Renogram), and Group II (n = 65), patients with GFR ≥ 60 mL/m. The pNGAL and uNGAL were measured within 2 days of the Renogram. Results. Both groups were matched with age, sex, and Child Pugh score. There was statistically significant difference between both groups regarding serum creatinine (1.98 ± 1.04 versus 1.38 ± 0.88 mg/dL; p = 0.003) and pNGAL level (5.79 ± 2.06 versus 7.25 ± 3.30 ng/dL; p = 0.019). Both groups were comparable (p > 0.05) for the uNGAL (6.00 ± 0.78 versus 6.03 ± 0.96 ng/mL). Unlike uNGAL, the pNGAL positively correlated with total GFR by Renogram (r = 0.3; p = 0.001). With a cutoff ≥4 ng/mL, pNGAL had 94.3% sensitivity and 1.5% specificity and PPV = 34, NPV = 33.3, LR+ = −175.1, and LR− = −60.6. Conclusion. The pNGAL is a promising marker of the renal function in patients with cirrhosis.

Urine neutrophil gelatinase associated lipocalin as an early marker of acute kidney injury in hematopoietic stem cell transplantation patients

Acute kidney injury (AKI) is common in hematopoietic stem cell transplantation (HSCT) patients with an incidence of 21-73%. Prevention and early diagnosis reduces the frequency and severity of this complication. Predictive biomarkers are of major importance to timely diagnosis. Neutrophil gelatinase associated lipocalin (NGAL) is a widely investigated novel biomarker for early diagnosis of AKI. However, no study assessed NGAL for AKI diagnosis in HSCT patients. We performed further analyses on gathered data from our recent trial to evaluate the performance of urine NGAL (uNGAL) as an indicator of AKI in 72 allogeneic HSCT patients. AKI diagnosis and severity were assessed using Risk-Injury-Failure-Loss-End-stage renal disease and AKI Network criteria. We assessed uNGAL on days -6, -3, +3, +9 and +15. Time-dependent Cox regression analysis revealed a statistically significant relationship between uNGAL and AKI occurrence. (HR = 1.04 (1.008-1.07), p = 0.01). There was a relation between uNGAL day + 9 to baseline ratio and incidence of AKI (unadjusted HR = 1.047 (1.012-1.083), p < 0.01). The area under the receiver-operating characteristic curve for day + 9 to baseline ratio was 0.86 (0.74-0.99, p < 0.01) and a cut-off value of 2.62 was 85% sensitive and 83% specific in predicting AKI. Our results indicated that increase in uNGAL augmented the risk of AKI and the changes of day +9 uNGAL concentrations from baseline could be of value for predicting AKI in HSCT patients. Additionally uNGAL changes preceded serum Cr raises by nearly 2 days.

Nephrotoxic effects of varenicline as the most effective drug used for smoking cessation: a preliminary experimental study

PURPOSE

Varenicline is a new most effective drug for smoking cessation. Its effect on kidney functions remains unclear. This study purposed to investigate whether varenicline causes nephrotoxicity in rats.

METHODS

Fifteen rats were randomly assigned to three groups: control, 0.0125 mg kg(-1) varenicline and 0.025 mg kg(-1) varenicline (single dose for 3 days, i.p.). Before and after experimental period, serum neutrophil gelatinase-associated lipocalin, creatinine and urea levels were measured. Total oxidant and antioxidant status were measured in kidney homogenates. Histological examination was performed in kidney.

RESULTS

The nephrotoxic effects of varenicline were detected by histopathological and biochemical examinations in the varenicline treatment groups. No change was observed in the control group.

CONCLUSIONS

These findings firstly indicate that a 3-day varenicline treatment causes nephrotoxic effects in rats.