Urine neutrophil gelatinase-associated lipocalin is an early marker of acute kidney injury in critically ill children: a prospective cohort study

The Role of Urinary Neutrophil Gelatinase-Associated Lipocalin in Predicting Acute Kidney Dysfunction in Patients With Liver Cirrhosis

Background

Early detection of acute kidney dysfunction (AKD) in cirrhotic patients is crucial. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been identified as an early marker of AKD. The aim of the study was to evaluate serial uNGAL as a marker and predictor of AKD in liver cirrhosis patients.

Methods

Serial uNGAL and serum creatinine (sCr) levels were measured daily during the first 6 days of admission. Furthermore, sCr levels and the estimated glomerular filtration rate (eGFR) were measured after 3 - 6 weeks. The uNGAL levels in patients with and without abnormal sCr were compared.

Results

Fifty-seven consecutive cirrhotic patients were enrolled in the study. Eight of 14 patients (57%) who developed abnormal uNGAL level also had abnormal sCr level (odds ratio (OR) = 3.4, 95% CI: 0.99 - 12.03, P = 0.05). After 6 weeks, 41% of patients exhibited an abnormal uNGAL level and abnormal sCr (OR = 6.7, 95% CI: 1.55 - 28.85, P = 0.01). Area under the curve (AUROC) and the best cut-off point for highest NGAL in 6 days were 0.64 and 72.55 ng/mL, respectively.

Conclusions

There is a modest association between highest uNGAL in the first 6 days of admission and sCr at week 6 in all participants. This may indicate that in cirrhotic patients, uNGAL level during the first 6 days of admission has a potential predictability for the development of high sCr and low eGFR 6 weeks later. The AUROC of 0.64 quantifies the overall ability of uNGAL to discriminate between those individuals who will have a raised sCr levels and those who will not.

Biomarkers of AKI Progression after Pediatric Cardiac Surgery

Background As children progress to higher stages of AKI, the risk for adverse outcomes dramatically increases. No reliable methods exist to predict AKI progression in hospitalized children. To determine if biomarkers of inflammation and kidney injury can predict AKI progression, we conducted a three-center prospective cohort study of children undergoing cardiopulmonary bypass.Methods On the first day of serum creatinine-defined AKI, we measured urine biomarkers (neutrophil gelatinase-associated lipocalin [NGAL], IL-18, kidney injury molecule 1, liver fatty acid binding protein [L-FABP], albumin, and cystatin C) and plasma biomarkers (IFN, IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, TNF-α, NGAL, and cystatin C). We defined AKI progression as a worsening of AKI stage or persisting stage 3 AKI (≥2 consecutive days).Results In all, 176 of 408 (43%) children developed postoperative AKI. Among the children with AKI, we diagnosed stages 1, 2, and 3 AKI in 145 (82.5%), 25 (14%), and six (3.5%) children, respectively, on the first day of AKI; 28 (7%) children had AKI progression. On the first day of AKI, nine of 17 biomarkers were significantly higher in patients with than without AKI progression. Urine L-FABP (among injury biomarkers) and plasma IL-8 (among inflammatory biomarkers) had the highest discrimination for AKI progression: optimism-corrected area under the curve, 0.70; 95% confidence interval, 0.58 to 0.81 and optimism-corrected area under the curve, 0.80; 95% confidence interval, 0.69 to 0.91, respectively.Conclusions If validated in additional cohorts, plasma IL-8 could be used to improve clinical care and guide enrollment in therapeutic trials of AKI.

Lipocalin2 Protects Human Embryonic Kidney Cells against Cisplatin-Induced Genotoxicity

Cisplatin is one of the most useful chemotherapeutics which performs its cytotoxic effect via accumulation of platinum resulting in oxidative stress, and destruction of cell DNA. This could probably cause secondary cancers in healthy tissues. Lipocalin2 (Lcn2) is a protein which its expression is increased in oxidative stresses. Therefore, the present study was performed to evaluate the protective effects of Lcn2 up-regulation on cisplatin genotoxicity. In order to up-regulate Lcn2 expression, HEK293 cells were transfected with pcDNA3.1-Lcn2 vector. Afterwards, stable cells consistently expressing Lcn2 were selected via screening with G418 antibiotic. Next, overexpression of Lcn2 was evaluated by RT-PCR and ELISA, comparing to the control non-transfected cells. Then, in order to evaluate the cytoprotective effects of Lcn2 overexpression, transfected and non-transfected cells were subjected to cisplatin treatment followed by MTT and alkaline Comet assays. RT-PCR and ELISA assays confirmed up-regulation of Lcn2 by the stable cells. MTT assay of the Lcn2 over-expressing cells showed higher IC50 values comparing to the non-transfected cells. Furthermore, the Comet assay confirmed Lcn2 protective effects on the cisplatin (1 µg/mL) induced genotoxicity. In the present study, for the first time, we showed the protective effect of Lcn2 on cisplatin induced genotoxicity. Therefore, one of the probable mechanisms of Lcn2 cytoprotctive effects under oxidative stress conditions could be due to the prevention of genotoxicity. However, further evaluations in this regard must be considered.

Urinary Neutrophil Gelatinase-Associated Lipocalin for the Diagnosis of Urinary Tract Infections

OBJECTIVES

To determine the accuracy of the novel biomarker urinary neutrophil gelatinase-associated lipocalin (uNGAL) to diagnose urinary tract infections (UTIs) in febrile infants and young children.

METHODS

Prospective cross-sectional study of febrile infants <3 months ( ≥ 38.0°C) and children 3 to 24 months (≥ 39.0°C) evaluated for UTIs. uNGAL levels, urinalysis, Gram-stain and culture were obtained. UTI was defined by colony counts.

RESULTS

Of 260 patients, 35 (13.5%) had UTIs. Median uNGAL levels were 215.1 ng/mL (interquartile range: 100.3-917.8) and 4.4 ng/mL (interquartile range: 1.6-11.8) in the groups diagnosed with and without UTIs, respectively. The area under the receiver-operating characteristic curve for uNGAL was 0.978 (95% confidence interval [CI]: 0.948-1.000). At a threshold uNGAL level of 39.1 ng/mL, sensitivity was 97.1% (95% CI: 83.4-99.9) and specificity was 95.6% (95% CI: 91.7-97.7). uNGAL had higher sensitivity than the combination of leukocyte esterase (in trace or greater amounts) or nitrite (+) (97.1%, 95% CI: 83.4-99.9 vs 74.3%, 95% CI: 56.4-86.9), with similar specificity (95.6%, 95% CI: 91.7-97.7 vs 97.3%, 95% CI: 94.0-98.9). uNGAL had higher sensitivity than Gram-stain (97.1%, 95% CI: 83.4-99.9 vs 74.3%, 95%: CI: 56.4-86.9), with similar specificity (95.6%, 95% CI: 91.7-97.7 vs 100.0%, 95% CI: 97.9-100.0).

CONCLUSIONS

uNGAL has substantial accuracy to identify those with and without UTIs in infants and young children. Further studies will need to confirm our findings and determine if uNGAL is a more cost-effective test than standard screening tests.

Urine neutrophil gelatinase-associated lipocalin and other biomarkers in infants with urinary tract infection and in febrile controls

BACKGROUND

Urine biomarkers are commonly used in the evaluation of acute kidney injury, and are gaining attention as tools for studying urinary tract infections (UTIs). We analyzed neutrophil gelatinase-associated lipocalin (NGAL) and seven other urine biomarkers to evaluate their usefulness in the diagnosis of UTI in infants.

METHODS

Eight urine biomarkers were analyzed in 108 infants with UTI. Controls were 64 febrile children without UTI and 13 healthy children. Logistic regression and construction of receiver operating characteristic (ROC) curves were performed for UTI patients versus febrile controls for all biomarkers.

RESULTS

The best biomarkers to differentiate between UTI and febrile controls were NGAL and interleukin 8 (IL8). Urine NGAL in absolute concentration and adjusted for creatinine had a sensitivity of 93% and 96% and a specificity of 95% and 100% for diagnosing UTI, with a cut-off concentration of 38 ng/mL and 233 ng/mg respectively.

CONCLUSIONS

Urine biomarkers, particularly NGAL, can aid in the diagnosis of UTI among febrile infants. The results suggest that in infants with fever and high NGAL, UTI is most likely, whereas in infants with fever and low NGAL, other causes of fever should be looked for.

Urinary neutrophil gelatinase-associated lipocalin and cystatin C compared to the estimated glomerular filtration rate to predict risk in patients with suspected acute myocardial infarction

INTRODUCTION

Impaired renal function, reflected by estimated glomerular filtration rate (eGFR) or cystatin C, is a strong risk predictor in the presence of acute myocardial infarction (AMI). Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is an early marker of acute kidney injury. uNGAL might also be a good predictor of outcome in patients with cardiovascular disease. Aim of the present study was to evaluate the prognostic value of uNGAL compared to eGFR and cystatin C in patients with suspected AMI.

METHODS

1818 patients were enrolled with suspected AMI. Follow-up information on the combined endpoint of death or non-fatal myocardial infarction was obtained 6months after enrolment and was available in 1804 patients. 63 events (3.5%) were registered.

RESULTS

While cystatin C and eGFR were strong risk predictors for the primary endpoint even adjusted for several variables, uNGAL was not independently associated with outcome: When applied continuously uNGAL was associated with outcome but did not remain a statistically significant predictor after several adjustments (i.e. eGFR). By adding cystatin C or uNGAL to GRACE risk score variables, only cystatin C could improve the predictive value while uNGAL showed no improvement.

CONCLUSION

We could show that cystatin C is an independent risk predictor in patients with suspected AMI and cystatin C can add improvement to the commonly used GRACE risk score. In contrast uNGAL is not independently associated with outcome and seems not to add further prognostic information to GRACE risk score.

Urine biomarkers of acute kidney injury in noncritically ill, hospitalized children treated with chemotherapy

BACKGROUND

Cisplatin (Cis), carboplatin (Carb), and ifosfamide (Ifos) are common nephrotoxic chemotherapies. Biomarkers of tubular injury may allow for early acute kidney injury (AKI) diagnosis.

PROCEDURE

We performed a two-center (Canada, United States) pilot study to prospectively measure serum creatinine (SCr), urine neutrophil gelatinase-associated lipocalin (NGAL), and interleukin-18 (IL-18) in children receiving Cis/Carb (27 episodes), Ifos (30 episodes), and in 15 hospitalized, nonchemotherapy patients. We defined AKI using the Kidney Disease Improving Global Outcomes (KDIGO) definition. We compared postchemotherapy infusion NGAL and IL-18 concentrations (immediate postdose to 3 days later) to pre-infusion concentrations. We calculated area under the receiver operating characteristic curve (AUC) for postinfusion biomarkers to discriminate for AKI.

RESULTS

Prechemotherapy infusion NGAL and IL-18 concentrations were not higher than nonchemotherapy control concentrations. Increasing chemotherapy dose was associated with increasing postinfusion (0-4 hr after infusion) NGAL (P < 0.05). Post-Ifos, immediate postdose, and daily postdose NGAL and IL-18 were significantly higher than pre-infusion biomarker concentrations (P < 0.05), during AKI episodes. NGAL and IL-18 did not rise significantly after Cis-Carb infusion, relative to predose concentrations (P > 0.05). NGAL and IL-18 measured immediately after Ifos infusion discriminated for AKI with AUCs is 0.80 (standard error = 0.13) and 0.73 (standard error = 0.16), respectively. NGAL and IL-18 were not diagnostic of Cis-Carb-associated AKI. When AUCs were adjusted for age, all biomarker AUCs (Cis-Carb and Ifos) improved.

CONCLUSION

Urine NGAL and IL-18 show promise as early AKI diagnostic tests in children treated with ifosfamide and may have a potential role in drug toxicity monitoring.

Accuracy of neutrophil gelatinase-associated lipocalin for acute kidney injury diagnosis in children: systematic review and meta-analysis

OBJECTIVE

To estimate the accuracy of Neutrophil Gelatinase-Associated Lipocalin (NGAL) as a biomarker for acute kidney injury (AKI) in children.

METHODS

A systematic review of the literature was performed. The review protocol was registered at PROSPERO (CRD 42015024153). We conducted searches in the following databases: Medline (PubMed), LILACS (BVS), SCOPUS (Elsevier), Embase (OVID), Cochrane Central Register of Controlled Trials (CENTRAL), Biomed Central, and ISI Web of Science, from January 1990 to October 2016. For inclusion, studies measured NGAL levels in plasma and urine for AKI in children. For each study, 2 × 2 contingency tables were developed. For statistical analysis we calculated the sensitivity, specificity and diagnostic odds ratio. For methodological assessment, we used Quality Assessment of Diagnostic Accuracy Studies-2. Software used for analysis was Stata 14, and RevMan 5.3.

RESULTS

In total 13 studies were analyzed, which included 1629 children. For urinary NGAL, the pooled sensitivity was 0.76 (95% CI 0.62-0.85) and a pooled specificity 0.93 (95% CI 0.88-0.96). The diagnostic odds ratio (DOR) for the detection of AKI was 43 (95% CI 16-115) and the Area under the curve (AUC) was 0.94 (95% CI 0.92-0.96). For plasma NGAL the combined sensitivity was 0.80 (95% CI 0.64-0.90) and a combined specificity was 0.87 (95% CI 0.74-0.94). The DOR was 26 (95% CI 8.0-82) and AUC was 0.90 (95% CI 0.87-0.94) for the detection of AKI in children.

CONCLUSION

The data suggest that NGAL levels can be an important biomarker for the early detection of AKI in children.

Subclinical Kidney Injury in Children Receiving Nonsteroidal Anti-Inflammatory Drugs After Cardiac Surgery

OBJECTIVE

To investigate the association of nonsteroidal anti-inflammatory drug (NSAID) administration with urinary neutrophil gelatinase-associated lipocalin (NGAL) levels in children following cardiopulmonary bypass (CPB) who did not develop acute kidney injury (AKI).

STUDY DESIGN

In this prospective observational study, urinary NGAL levels were investigated in 210 children who underwent cardiothoracic surgery requiring CPB. Children with clinical AKI (defined as an increase in serum creatinine ≥50% from baseline within 72 hours of CPB) were excluded from the analysis. NSAIDs were administered no sooner than 24 hours after CPB. NGAL levels were compared between children who received NSAIDs (n = 146) and those who did not receive NSAIDs (n = 64).

RESULTS

The median age was 3.2 years in the children who received NSAIDs and 2.5 years in those who did not receive NSAIDs (P = .05). Before NSAID administration at 24 hours following CPB, the median NGAL level was 15 ng/mL in both groups (P = .92). Following NSAID administration, the median urinary NGAL level increased to 83 ng/mL (IQR, 45-95 ng/mL) at 72 hours after CPB in those receiving NSAIDs (P < .001). In contrast, the median NGAL level decreased to 10 ng/mL (IQR, 5.4-15.9 ng/mL) at 72 hours after CPB in those who did not receive NSAIDs (P = .01). In multivariable analysis, children receiving NSAIDs demonstrated a 5-fold elevation of urinary NGAL levels at 60-72 hours following CPB compared with those who did not receive NSAIDs (P < .001).

CONCLUSION

NSAID administration was associated with a significant increase in urinary NGAL in children who did not develop clinical AKI following CPB. This indicates that NGAL can detect NSAID-induced subclinical kidney injury in this population.

Contrast-Induced Acute Kidney Injury: Pathophysiology, Manifestations, Prevention, and Management

Contrast-induced acute kidney injury is a phenomenon that has been extensively studied throughout the years. There is a large volume of literature documenting this risk, and most radiology departments and radiologists use this information when making decisions regarding contrast administration. A review of the current information on the topic of contrast-induced acute kidney injury is necessary to ensure that the risks of intravenous contrast are properly weighed against the benefits of a contrast-enhanced computed tomography scan.

Biomarkers of acute kidney injury: the pathway from discovery to clinical adoption

Acute kidney injury (AKI) is a common complication of critical illnesses and has a significant impact on outcomes, including mortality and morbidities. Unfortunately, apart from prophylactic measures, no effective treatment for this syndrome is known. Therefore, early recognition of AKI not only can provide better opportunities for preventive interventions, but also opens many gates for research and development of effective therapeutic options. Over the last few years, several new AKI biomarkers have been discovered and validated to improve early detection, differential diagnosis, and differentiation of patients into risk groups for progressive renal failure, need for renal replacement therapy (RRT), or death. These novel AKI biomarkers complement serum creatinine (SCr) and urine output, which are the standard diagnostic tools for AKI detection. In this article, we review the available literature on characteristics of promising AKI biomarkers that are currently the focus of preclinical and clinical investigations. These biomarkers include neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), liver-type fatty acid-binding protein, interleukin 18 (lL-18), insulin-like growth factor-binding protein 7, tissue inhibitor of metalloproteinase 2 (TIMP-2), calprotectin, urine angiotensinogen (AGT), and urine microRNA. We then describe the clinical performance of these biomarkers for diagnosis and prognostication. We also appraise each AKI biomarker's advantages and limitations as a tool for early AKI recognition and prediction of clinical outcomes after AKI. Finally, we review the current and future states of implementation of biomarkers in the clinical practice.

Use of biomarkers in pediatric sepsis: literature review

Despite advances in recent years, sepsis is still a leading cause of hospitalization and mortality in infants and children. The presence of biomarkers during the response to an infectious insult makes it possible to use such biomarkers in screening, diagnosis, prognosis (risk stratification), monitoring of therapeutic response, and rational use of antibiotics (for example, the determination of adequate treatment length). Studies of biomarkers in sepsis in children are still relatively scarce. This review addresses the use of biomarkers in sepsis in pediatric patients with emphasis on C-reactive protein, procalcitonin, interleukins 6, 8, and 18, human neutrophil gelatinase, and proadrenomedullin. Assessment of these biomarkers may be useful in the management of pediatric sepsis.

Biomarkers for Early Acute Kidney Injury Diagnosis and Severity Prediction: A Pilot Multicenter Canadian Study of Children Admitted to the ICU

OBJECTIVE

Acute kidney injury occurs early in PICU admission and increases risks for poor outcomes. We evaluated the feasibility of a multicenter acute kidney injury biomarker urine collection protocol and measured diagnostic characteristics of urine neutrophil gelatinase-associated lipocalin, interleukin-18, and liver fatty acid binding protein to predict acute kidney injury and prolonged acute kidney injury.

DESIGN

Prospective observational pilot cohort study.

SETTING

Four Canadian tertiary healthcare PICUs.

PATIENTS

Eighty-one children 1 month to 18 years old. Exclusion criteria were as follows: cardiac surgery, baseline severe kidney disease, and inadequate urine or serum for PICU days 1-3.

INTERVENTIONS

PICUs performed standardized urine collection protocol to obtain early PICU admission urine samples, with deferred consent.

MEASUREMENTS AND MAIN RESULTS

Study barriers and facilitators were recorded. Acute kidney injury was defined based on Kidney Disease: Improving Global Outcomes serum creatinine criteria (acute kidney injuryserum creatinine) and by serum creatinine and urine output criteria (acute kidney injuryserum creatinine+urine output) Prolonged acute kidney injury was defined as acute kidney injury duration of 48 hours or more. PICU days 1-3 neutrophil gelatinase-associated lipocalin, interleukin-18, and liver fatty acid binding protein were evaluated for acute kidney injury prediction (area under the curve). Biomarkers on the first day of acute kidney injury attainment (day 1 acute kidney injury) were evaluated for predicting prolonged acute kidney injury. Eighty-two to 95% of subjects had urine collected from PICU days 1-3. Acute kidney injuryserum creatinine developed in 16 subjects (20%); acute kidney injuryserum creatinine+urine output developed in 38 (47%). On PICU day 1, interleukin-18 predicted acute kidney injuryserum creatinine with area under the curve=0.82, but neutrophil gelatinase-associated lipocalin and liver fatty acid binding protein predicted acute kidney injuryserum creatinine with area under the curve of less than or equal to 0.69; on PICU day 2, area under the curve was higher (not shown). Interleukin-18 and liver fatty acid binding protein on day 1 acute kidney injury predicted prolonged acute kidney injuryserum creatinine (area under the curve=0.74 and 0.83, respectively). When acute kidney injuryserum creatinine+urine output was used to define acute kidney injury, biomarker area under the curves were globally lower.

CONCLUSIONS

Protocol urine collection to procure early admission samples is feasible. Individual biomarker acute kidney injury prediction performance is highly variable and modest. Larger studies should evaluate utility and cost effectiveness of using early acute kidney injury biomarkers.

Increased urinary neutrophil gelatinase-associated lipocalin in very-low-birth-weight infants with oliguria and normal serum creatinine

BACKGROUND

In infants, oliguria is defined as a urine output of <1.5 mL/kg/h. The aim of our study was to assess the impact of oliguria on urinary neutrophil gelatinase-associated lipocalin (NGAL) and serum cystatin C (CysC) levels in very-low-birth-weight infants (VLBWIs) with a normal serum creatinine (Cr) level.

METHODS

Fifty-seven VLBWIs were enrolled in the study. Urinary NGAL, serum CysC and Cr levels and urinary NGAL/Cr ratios were measured. Infants with Apgar scores of >5 at 5 min and/or a serum Cr level of >1.5 mg/dL or those treated for patent ductus arteriosus were excluded. In case of antibiotic treatment, blood and urine samples were collected at ≥48 h after discontinuation of antibiotic treatment.

RESULTS

There was a significant difference in gestational age between infants with oliguric episodes during hospitalization and those without, but not in birth weight, perinatal or postnatal factors. Gestational age was negatively correlated with urinary NGAL and serum CysC levels and urinary NGAL/Cr ratio (p < 0.05), whereas postnatal age was negatively correlated with serum Cr level and urinary NGAL/Cr ratio (p < 0.05). Of the 117 urine and blood samples collected, 25 (21.4%) were obtained from neonates with oliguric episodes. After adjusting for gestational age and postnatal age, comparison of samples collected in infants with and without oliguric episodes revealed significant differences in the mean level of urinary NGAL and in the urinary NGAL/Cr ratio, but not in mean serum CysC or serum Cr levels. The urinary NGAL level [area under the curve (AUC) 0.886, 95% confidence interval (CI) 0.814-0.937] and urinary NGAL/Cr ratio (AUC 0.853, 95% CI 0.775-0.911) showed significantly greater discrimination for oliguria than serum CysC (AUC 0.610, 95% CI: 0.515-0.699) or serum Cr (AUC 0.747, 95%CI 0.659-0.823) levels.

CONCLUSIONS

Urinary NGAL level and urinary NGAL/Cr ratio were more sensitive markers for the presence of oliguria in VLBWIs with normal serum Cr levels than serum CysC level.

Design and Methods of the Pan-Canadian Applying Biomarkers to Minimize Long-Term Effects of Childhood/Adolescent Cancer Treatment (ABLE) Nephrotoxicity Study: A Prospective Observational Cohort Study

BACKGROUND

Childhood cancer survivors experience adverse drug events leading to lifelong health issues. The Applying Biomarkers to Minimize Long-Term Effects of Childhood/Adolescent Cancer Treatment (ABLE) team was established to validate and apply biomarkers of cancer treatment effects, with a goal of identifying children at high risk of developing cancer treatment complications associated with thrombosis, graft-versus-host disease, hearing loss, and kidney damage. Cisplatin is a chemotherapy well known to cause acute and chronic nephrotoxicity. Data on biomarkers of acute kidney injury (AKI) and late renal outcomes in children treated with cisplatin are limited.

OBJECTIVE

To describe the design and methods of the pan-Canadian ABLE Nephrotoxicity study, which aims to evaluate urine biomarkers (neutrophil gelatinase-associated lipocalin [NGAL] and kidney injury molecule-1 [KIM-1]) for AKI diagnosis, and determine whether they predict risk of long-term renal outcomes (chronic kidney disease [CKD], hypertension).

DESIGN

This is a 3-year observational prospective cohort study.

SETTING

The study includes 12 Canadian pediatric oncology centers.

PATIENTS

The target recruitment goal is 150 patients aged less than 18 years receiving cisplatin. Exclusion criteria: Patients with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 or a pre-existing renal transplantation at baseline.

MEASUREMENTS

Serum creatinine (SCr), urine NGAL, and KIM-1 are measured during cisplatin infusion episodes (pre-infusion, immediate post-infusion, discharge sampling). At follow-up visits, eGFR, microalbuminuria, and blood pressure are measured and outcomes are collected.

METHODS

Outcomes: AKI is defined as per SCr criteria of the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. CKD is defined as eGFR <90 mL/min/1.73m2 or albumin-to-creatinine ratio≥3mg/mmol. Hypertension is defined as per guidelines. Procedure: Patients are recruited before their first or second cisplatin cycle. Participants are evaluated during 2 cisplatin infusion episodes (AKI biomarker validation) and at 3, 12, and 36 months post-cisplatin treatment (late outcomes).

LIMITATIONS

The study has a relatively moderate sample size and short follow-up duration. There is potential for variability in data collection since multiple sites are involved.

CONCLUSIONS

ABLE will provide a national platform to study biomarkers of late cancer treatment complications. The Nephrotoxicity study is a novel study of AKI biomarkers in children treated with cisplatin that will greatly inform on late cisplatin renal outcomes and follow-up needs.

Identifying High-Risk Medications Associated with Acute Kidney Injury in Critically Ill Patients: A Pharmacoepidemiologic Evaluation

BACKGROUND

Nephrotoxic medications are a common cause of acute kidney injury (AKI). Critically ill children receive more medication than other inpatients; however, the risk of nephrotoxic medication-induced AKI in these children is not well understood.

OBJECTIVE

The aim of this study was to determine the association between exposure to nephrotoxic medications in the intensive care unit (ICU) and the development of AKI amongst critically ill children, adjusting for differences in underlying risk.

METHODS

We conducted a nested case-control study among a cohort of patients admitted to a paediatric intensive care unit between January 2006 and June 2009. Cases were identified according to the RIFLE criteria. Using incidence density sampling, controls were matched 1:1 according to pre-ICU nephrotoxic drug exposure. Administration of nephrotoxic medications and other known risk factors of AKI were evaluated during the ICU stay prior to the diagnosis of AKI.

RESULTS

A total of 914 patients in the cohort developed AKI and had an identifiable matched control. Eighty-seven percent of cases and 74% of controls were exposed to one or more nephrotoxic medications in the ICU during the study period. Furosemide (administered to 67.8% of patients), vancomycin (28.7%), and gentamicin (21.4%) were the most frequently administered nephrotoxic drugs. Patients who developed AKI were more likely to be exposed to at least one nephrotoxic medication and risk increased with increasing number of nephrotoxic medications. Ganciclovir (adjusted odds ratio [AOR] 4.7; 95% CI 1.7-13.0), furosemide (AOR 1.9; 95% CI 1.4-2.4), and gentamicin (AOR 1.8; 95% CI 1.4-2.4) significantly increased the odds of developing AKI after adjusting for underlying differences in risk factors of AKI.

CONCLUSION

This is the first study to assess the association between risk-adjusted nephrotoxic medication exposure and the development of AKI in critically ill children. Nephrotoxic medication exposure was common amongst children in the ICU and we found AKI was associated with the administration of specific drugs after adjustment for important risk factors.

Correlation of Impedance Threshold Device use during cardiopulmonary resuscitation with post-cardiac arrest Acute Kidney Injury

PURPOSE

To assess whether use of Impedance Threshold Device (ITD) during cardiopulmonary resuscitation (CPR) reduces the degree of post-cardiac arrest Acute Kidney Injury (AKI), as a result of improved hemodynamics, in a porcine model of ventricular fibrillation (VF) cardiac arrest.

METHODS

After 8 min of untreated cardiac arrest, the animals were resuscitated either with active compression-decompression (ACD) CPR plus a sham ITD (control group, n=8) or with ACD-CPR plus an active ITD (ITD group, n=8). Adrenaline was administered every 4 min and electrical defibrillation was attempted every 2 min until return of spontaneous circulation (ROSC) or asystole. After ROSC the animals were monitored for 6 h under general anesthesia and then returned to their cages for a 48 h observation, before euthanasia. Two novel biomarkers, Neutrophil Gelatinase-Associated Lipocalin (NGAL) in plasma and Interleukin-18 (IL-18) in urine, were measured at 2 h, 4 h, 6 h, 24 h and 48 h post-ROSC, in order to assess the degree of AKI.

RESULTS

ROSC was observed in 7 (87.5%) animals treated with the sham valve and 8 (100%) animals treated with the active valve (P=NS). However, more than twice as many animals survived at 48 h in the ITD group (n=8, 100%) compared to the control group (n=3, 37.5%). Urine IL-18 and plasma NGAL levels were augmented post-ROSC in both groups, but they were significantly higher in the control group compared with the ITD group, at all measured time points.

CONCLUSION

Use of ITD during ACD-CPR improved hemodynamic parameters, increased 48 h survival and decreased the degree of post-cardiac arrest AKI in the resuscitated animals.

Lipocalin-2 Promotes Endoplasmic Reticulum Stress and Proliferation by Augmenting Intracellular Iron in Human Pulmonary Arterial Smooth Muscle Cells

Endoplasmic reticulum (ER) stress, a feature of many conditions associated with pulmonary hypertension (PH), is increasingly recognized as a common response to promote proliferation in the walls of pulmonary arteries. Increased expression of Lipocalin-2 in PH led us to test the hypothesis that Lipocalin-2, a protein known to sequester iron and regulate it intracellularly, might facilitate the ER stress and proliferation in pulmonary arterial smooth muscle cells (PASMCs). In this study, we observed greatly increased Lcn2 expression accompanied with increased ATF6 cleavage in a standard rat model of pulmonary hypertension induced by monocrotaline. In cultured human PASMCs, Lcn2 significantly promoted ER stress (determined by augmented cleavage and nuclear localization of ATF6, up-regulated transcription of GRP78 and NOGO, increased expression of SOD2, and mild augmented mitochondrial membrane potential) and proliferation (assessed by Ki67 staining and BrdU incorporation). Lcn2 promoted ER stress accompanied with augmented intracellular iron levels in human PASMCs. Treatment human PASMCs with FeSO4 induced the similar ER stress and proliferation response and iron chelator (deferoxamine) abrogated the ER stress and proliferation induced by Lcn2 in cultured human PASMCs. In conclusion, Lcn2 significantly promoted human PASMC ER stress and proliferation by augmenting intracellular iron. The up-regulation of Lcn2 probably involved in the pathogenesis and progression of PH.

Drug-associated acute kidney injury: who's at risk?

The contribution of nephrotoxic medications to the development of acute kidney injury (AKI) is becoming better understood concomitant with the increased incidence of AKI in children. Treatment of AKI is not yet available, so prevention continues to be the most effective approach. There is an opportunity to mitigate severity and prevent the occurrence of AKI if children at increased risk are identified early and nephrotoxins are used judiciously. Early detection of AKI is limited by the dependence of nephrologists on serum creatinine as an indicator. Promising new biomarkers may offer early detection of AKI prior to the rise in serum creatinine. Early detection of evolving AKI is improving and offers opportunities for better management of nephrotoxins. However, the identification of patients at increased risk will remain an important first step, with a focus on the use of biomarker testing and interpretation of the results.

Serum cystatin C for acute kidney injury evaluation in children treated with aminoglycosides

BACKGROUND

Serum cystatin C (CysC) is a more accurate glomerular filtration rate marker than serum creatinine (SCr) and may rise more quickly with acute kidney injury (AKI).

METHODS

We performed a prospective cohort study of 81 non-critically ill children during 110 aminoglycoside (AG) treatments. We calculated area under the curve (AUC) for CysC to diagnose SCr-defined AKI and predict persistent AKI. SCr-AKI definition was based on the Kidney Disease: Improving Global Outcomes (≥stage 1: ≥50 % or 26.5 μmol/l SCr rise from baseline; stage 2: SCr doubling); CysC-AKI was based on a modified version using CysC rise.

RESULTS

SCr-AKI and CysC-AKI developed in 45 and 48 % treatments, respectively. CysC rise predicted stage 1 (AUC = 0.75, 95 % CI 0.60-0.90) and 2 (AUC = 0.85, 95 % CI 0.75-0.95) SCr-AKI 2 days before SCr-AKI attainment. The best combined sensitivity/specificity for percent CysC rise to predict stage 1 SCr-AKI was with a 44 % CysC rise (sensitivity = 65 %, specificity = 83 %). CysC rise on day of SCr-AKI development was associated with SCr-AKI ≥48 h (AUC = 0.73, 95 % CI 0.56-0.90) and ≥50 % persistent SCr rise at treatment end (AUC = 0.76, 95 % CI 0.61-0.90).

CONCLUSIONS

CysC is as an early AKI biomarker and predictive of persistent AKI on aminoglycoside treatment.

The Effect of Furosemide on the Level of Neutrophil Gelatinase-associated Lipocalin in Critically Hospitalized Patients with Acute Kidney Injury

BACKGROUND AND AIMS

Oliguric acute kidney injury (AKI), commonly attributed to a more severe degree of renal injury, is associated with poorer prognosis than nonoliguric form. The aim of this study was to determine the effect of furosemide therapy on kidney function and on the level of neutrophil gelatinase-associated lipocalin (NGAL) in critically hospitalized patients in the Intensive Care Unit (ICU).

MATERIALS AND METHODS

In this randomized controlled trial, 106 ICU patients with AKI were assigned into furosemide and control groups. In furosemide group, 40-80 mg of intravenous furosemide was administrated, followed by 1-5 mg/h furosemide infusion. In control group, patients received standard treatment. Serum and urinary NGAL were measured on the 1^st, 3^rd, and 7^th days of the study.

RESULTS

The results of this study indicated that during the study, serum blood urea nitrogen levels of patients increased in both groups; this, however, was significant only in the control group (P = 0.009). Both plasma and urine NGAL decreased significantly (P < 0.05) in both groups. The findings of 28-day mortality follow-up revealed that 20% and 28% of patients died in the furosemide and the control groups, respectively.

CONCLUSIONS

NGAL was not found to reflect any positive or negative effects of Furosemide in patients with AKI.

Neutrophil Gelatinase-Associated Lipocalin in Cats with Naturally Occurring Chronic Kidney Disease

Background

Neutrophil gelatinase‐associated lipocalin (NGAL) is a biomarker for the early prediction of renal damage and the progression of chronic kidney disease (CKD) in humans and dogs.

Hypothesis

Neutrophil gelatinase‐associated lipocalin also may play a role in the progression of CKD in cats.

Animals

Eighty CKD and 18 control cats.

Methods

Cats were categorized into different stages according to the International Renal Interest Society (IRIS) staging system. Urine and plasma samples were collected and tested for NGAL concentrations using an in‐house sandwich ELISA system and urinary NGAL (uNGAL)‐to‐creatinine ratio (UNCR) was determined. Cats in which serum creatinine concentration increased by >0.5 mg/dL from baseline within 30 days were defined as exhibiting progression.

Results

The urinary NGAL and UNCR of CKD cats were significantly higher than those of healthy cats (P < .05) and were highly correlated with serum creatinine concentration. The area under the receiver operating characteristic curve (AUROC) for uNGAL, when predicting the progression of CKD, was 0.71 and the best cutoff value was 2.06 ng/mL with a sensitivity of 76.9% and a specificity of 75%. The AUROC for UNCR when predicting the progression of CKD was 0.79 and the best cutoff value was 4.08 × 10⁻⁶ with a sensitivity of 76.9% and specificity of 79.2%. Cats with UNCR values higher than their cutoffs experienced significantly faster deterioration with a median of 19 days.

Conclusions

Both urinary NGAL and UNCR are useful markers for the prediction of CKD progression in cats.

KIM-1 Is a Potential Urinary Biomarker of Obstruction: Results from a Prospective Cohort Study

INTRODUCTION

Partial or complete obstruction of the urinary tract is a common and challenging urological condition that may occur in patients of any age. Serum creatinine is the most commonly used method to evaluate global renal function, although it has low sensitivity for early changes in the glomerular filtration rate or unilateral renal pathology. Hence, finding another measurable parameter that reflects the adaptation of the renal physiology to these circumstances is important. Several recent studies have assessed the use of new biomarkers of acute kidney injury (AKI), but the information among patients with stone disease and those with obstructive uropathy is limited.

MATERIAL AND METHODS

A prospective cohort study was conducted to determine the urinary levels of kidney injury molecule-1 (KIM-1), Total and Monomeric neutrophil gelatinase-associated lipocalin (NGAL) in patients with hydronephrosis secondary to renal stone disease, congenital ureteropelvic junction obstruction or ureteral stricture. Comparison between patients with hydronephrosis and no hydronephrosis was carried out along with correlation analysis to detect factors associated with biomarker expression.

RESULTS

Urinary levels of KIM-1 significantly decreased after hydronephrosis treatment in patients with unilateral obstruction (1.19 ng/mL vs 0.76 ng/mL creatinine, p = 0.002), additionally KIM-1 was significantly higher in patients with hydronephrosis compared to stone disease patients without radiological evidence of obstruction (1.19 vs 0.64, p = 0.006). Total and Monomeric NGAL showed a moderate correlation with the presence of leukocyturia. We found that a KIM-1 value of 0.735 ng/mg creatinine had a sensitivity of 75% and specificity of 67% to predict the presence of hydronephrosis in preoperative studies (95% CI 0.58-0.87, p = 0.006).

CONCLUSION

Our results show that KIM-1 is a promising biomarker of subclinical AKI associated with hydronephrosis in urological patients. NGAL values were influenced by the presence of leukocyturia, limiting its usefulness in this population.

Acute Kidney Injury: Diagnostic Approaches and Controversies

Acute kidney injury (AKI) is a significant independent risk factor for morbidity and mortality. In the last ten years a large number of publications have highlighted the limitations of traditional approaches and the inadequacies of conventional biomarkers to diagnose and monitor renal insufficiency in the acute setting. A great effort was directed not only to the discovery and validation of new biomarkers aimed to detect AKI more accurately but also to standardise the definition of AKI. Despite the advances in both areas, biomarkers have not yet entered into routine clinical practice and the definition of this syndrome has many areas of uncertainty. This review will discuss the controversies in diagnosis and the potential of novel biomarkers to improve the definition of the syndrome.

Neutrophil gelatinase-associated lipocalin production negatively correlates with HK-2 cell impairment: Evaluation of NGAL as a marker of toxicity in HK-2 cells

Neutrophil gelatinase-associated lipocalin is an extracellular protein produced mostly in kidney. Recently, it has become a promising biomarker of renal damage in vivo. On the other hand, the validation of NGAL as a biomarker for nephrotoxicity estimation in vitro has not been characterized in detail yet. Since the HK-2 cells are frequently used human kidney cell line, we aimed to characterize the production of NGAL in these cells and to evaluate NGAL as a possible marker of cell impairment. We used heavy metals (mercury, cadmium), peroxide, drugs (acetaminophen, gentamicin) and cisplatin to mimic nephrotoxicity. HK-2 cells were incubated with selected compounds for 1-24h and cell viability was measured together with extracellular NGAL production. We proved that HK-2 cells possess a capacity to produce NGAL in amount of 2pg/ml/h. We found a change in cell viability after 24h incubation with all tested toxic compounds. The largest decrease of the viability was detected in mercury, acetaminophen, cisplatin and gentamicin. Unexpectedly, we found also a significant decrease in NGAL production in HK-2 cells treated with these toxins for 24h: to 11±5%, 54±5%, 57±6% and 76±9% respectively, compared with controls (=100%). Our results were followed with qPCR analysis when we found no significant increase in LCN2 gene expression after 24h incubation. We conclude that extracellular NGAL production negatively correlates with HK-2 cell impairment.

Is urinary neutrophil gelatinase-associated lipocalin able to predict acute kidney injury episodes in very low birth weight infants in clinical settings?

BACKGROUND

We evaluated the potential utility of elevated urinary neutrophil gelatinase-associated lipocalin (UNGAL) concentration as a screening test for early identification of acute kidney injury (AKI) in very low birth weight (VLBW) newborns.

METHODS

Urine for UNGAL analysis was collected prospectively daily until 32 wk postmenstrual age in 91 VLBW newborns, yielding 2,899 specimens. UNGAL values > 50 ng/ml were considered elevated. AKI was defined as two or more consecutive elevations in s[Cr] above the 95^th percentile adjusted for gestational age and chronological age within a 48 h period. We compared UNGAL values taken during the 5 d prior to AKI onset (pre-AKI) to values taken during non-AKI days.

RESULTS

Overall, 15 episodes of AKI were identified in 13 infants. UNGAL was available in 44 pre-AKI days and 969 non-AKI days. UNGAL > 50 ng/ml occurred more often in pre-AKI days than in non-AKI days (risk ratio 3.48 (1.89, 6.40)). Positive and negative likelihood ratios were 1.92 (1.52, 2.41) and 0.52 (0.34, 0.78), respectively.

CONCLUSION

Although UNGAL elevation > 50 ng/ml discriminates between pre-AKI and non-AKI days, high false positive and false negative rates limit utility as a screening test in VLBW newborns.

Non-dialytic management of acute kidney injury in newborns

Treating acute kidney injury (AKI) in newborns is often challenging due to the functional immaturity of the neonatal kidney. Because of this physiological limitation, renal replacement therapy (RRT) in this particular patient population is difficult to execute and may lead to unwanted complications. Although fluid overload and electrolyte abnormalities, as seen in neonatal AKI, are indications for RRT initiation, there is limited evidence that RRT initiated in the first year of life improves long-term outcome. The underlying cause of AKI in a newborn patient should determine the treatment strategies to restore appropriate renal function. However, our understanding of this common clinical condition remains limited, as no standardized, evidence-based definition of neonatal AKI currently exists. Non-dialytic management of AKI in these patients may restore appropriate renal function to these patients without exposure to complications often encountered with RRT.

Serum NGAL and copeptin levels as predictors of acute kidney injury in asphyxiated neonates

Background

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

Methods

A prospective cohort study was conducted on 43 term neonates. Umbilical cord blood and 24 h after birth serum NGAL, copeptin, creatinine, and molality were measured in all asphyxiated and controls neonates.

Results

During the study period, 8 of asphyxiated nenates (18.6 %) suffered from AKI, while 35 newborns have no signs of AKI and 30 healthy infants. We did not observe any differences in creatinine and copeptin levels, as well as serum osmolality in all three investigated groups (AKI, no-AKI, and controls) in cord blood, and 24 h after birth. Serum NGAL levels in umbilical cord blood were significantly higher in the AKI group (174.3 ng/mL) compared with no-AKI (88.5 ng/mL, p = 0.01) and control groups (28.5 ng/mL, p < 0.001), and 24 h after birth (respectively, AKI 152.5 ng/mL vs no-AKI 74.9 ng/mL, p = 0.02 vs controls 39.1 ng/mL, p < 0.001). NGAL concentration showed a strong negative correlation to umbilical artery pH (Rho = −0.42, p = 0.04), base excess (Rho = −0.31, p = 0.03), and Apgar score in 1st min (Rho = −0.41, p = 0.02) and 5th min of life (Rho = −0.20, p = 0.001). ROC curve analysis demonstrated a good predictive value for NGAL levels (>140.7 ng/mL) which allows to diagnose AKI in asphyxiated patients with 88.9 % sensitivity (95 % CI 75–95 %) and 95.0 % specificity (95 % CI 76–99 %).

Conclusion

NGAL seems to be a promising marker, even in subclinical AKI in neonates, due to its high specificity, but copeptin did not meet expectations.

Early urinary biomarkers of acute kidney injury in preterm infants

BACKGROUND

Acute kidney injury (AKI) in the neonatal intensive care setting is multifactorial and is associated with significant morbidity and mortality. This study evaluates the utility of novel urinary biomarkers to predict the development and/or severity AKI in preterm infants.

METHODS

We performed a case-control study on a prospective cohort of preterm infants (<32 wk), to compare seven urine biomarkers between 25 infants with AKI and 20 infants without AKI.

RESULTS

Infants with AKI had significantly higher neutrophil gelatinase-associated lipocalin (NGAL) (median, control (CTRL) vs. AKI; 0.598 vs. 4.24 µg/ml; P < 0.0001). In contrast, urinary epidermal growth factor (EGF) levels were significantly lower in infants who developed AKI compared to controls (median, CTRL vs. AKI; 0.016 vs. 0.006 µg/ml; P < 0.001). The area under the curve (AUC) for NGAL for prediction of stage I AKI on the day prior to AKI diagnosis (day-1) was 0.91, and for the prediction of stage II/III, AKI was 0.92. Similarly, urine EGF was a predictor of renal injury on day -1 (AUC: 0.97 for stage I and 0.86 for stage II/III AKI).

CONCLUSION

Urinary biomarkers may be useful to predict AKI development prior to changes in serum creatinine (SCr) in preterm infants.

Urinary NGAL-Positive Acute Kidney Injury and Poor Long-term Outcomes in Hospitalized Patients

Introduction

Neutrophil gelatinase−associated lipocalin (NGAL) is a widely studied biomarker of renal tubular injury. Urinary NGAL (uNGAL) during acute kidney injury (AKI) predicts short-term adverse outcomes. However, the long-term predictive value is unknown.

Methods

We performed a prospective observational study of 145 patients with hospital-acquired AKI according to Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) criteria and analyzed the long-term predictive value of uNGAL at the time of AKI. We defined a composite outcome of all-cause mortality and the development of end-stage renal disease (ESRD).

Results

In all, 61 AKI patients died and 22 developed ESRD within 6 months. The uNGAL levels were significantly higher in patients with poor long-term outcomes. uNGAL levels ≥362 μg/l (highest quartile) and uNGAL levels between 95 and 362 μg/l (third quartile) were associated with hazard ratios of 3.7 (95% confidence interval, 2.1–6.5) and 1.9 (1.1–3.5), respectively, compared with uNGAL levels <95 μg/l (lower quartiles). After 6 months, 67% and 43% of patients within the highest and third uNGAL quartile, respectively, had either progressed to ESRD or died, compared to only 21% of patients with uNGAL in the lower 2 quartiles (P < 0.001). In multivariable Cox regression analyses accounting for conventional predictors, uNGAL was the strongest independent predictor of adverse long-term outcomes. The association of uNGAL levels and poor long-term outcomes remained significant in the subgroup of 107 AKI survivors discharged without requiring dialysis (P = 0.002).

Discussion

These data indicate that elevated uNGAL levels at AKI diagnosis predict poor long-term outcomes.

Urinary Neutrophil Gelatinase-Associated Lipocalin Levels in Neonates

BACKGROUND

Acute kidney injury (AKI) is common in preterm infants and is associated with high mortality and morbidity. New biomarkers for the early detection of AKI have been identified. Specifically, urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a new and powerful biomarker for AKI and sepsis. Our study evaluated the reference range of uNGAL in healthy neonates in Taiwan.

METHODS

This study examined 24 preterm and 38 term infants without clinical complications. Urine samples were collected and the uNGAL values were measured at postnatal age (PNA) 3 days, 7 days, 14 days, and 21 days in the preterm infants and at PNA 3 days in the term infants. The uNGAL values were tested using enzyme-linked immunosorbent assay.

RESULTS

The median uNGAL values in the preterm infants at PNA 3 days, 7 days, 14 days, and 21 days were 41.52 ng/mL, 35.82 ng/mL, 43.79 ng/mL, and 30.85 ng/mL, respectively. The median value at PNA 3 days in the term infants was 88.1 ng/mL. No significant differences associated with gestational age, birth body weight, or PNA were observed among the preterm infants. However, the uNGAL values in the female term infants were higher than those in the male term infants (p = 0.003).

CONCLUSION

This study presents preliminary data on uNGAL levels in neonates in Taiwan. A large-scale study investigating the correlations between uNGAL and with gestational age, birth body weight, sex, and PNA is recommended.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) distinguishes sustained from transient acute kidney injury after general surgery

Introduction

This prospective study tests the hypothesis that after general surgery urinary neutrophil gelatinase–associated lipocalin (NGAL) can distinguish between sustained acute kidney injury (AKI), typical of nephron damage, and transient AKI, commonly seen with hemodynamic variation and prerenal azotemia.

Methods

Urine was collected in 510 patients within 2 to 3 hours after general surgery, and urinary NGAL was determined using enzyme-linked immunosorbent assay. Patients who met AKIN stage 1 criteria of AKI were subclassified into those with sustained AKI (serum creatinine elevation for at least 3 days) and those with transient AKI (serum creatinine elevation for less than 3 days).

Results

Seventeen of 510 patients (3.3%) met the stage 1 AKIN criteria within 48 hours of surgery. Elevations in serum creatinine were sustained in 9 and transient in 8 patients. Urinary NGAL was significantly elevated only in patients with sustained AKI (204.8 ± 411.9 ng/dl); patients with transient AKI had urinary NGAL that was indistinguishable from that of patients who did not meet AKIN criteria at all (30.8 ± 36.5 ng/dl vs. 31.9 ± 113 ng/dl). The area under the curve of the receiver operating characteristic curve of urinary NGAL to predict sustained AKI was 0.85 (95% confidence interval: 0.773–0.929, P < 0.001).

Discussion

Urinary NGAL levels measured 2 to 3 hours after surgery were able to distinguish the kinetics of creatinine (sustained AKI vs. transient AKI) over the subsequent week. Transient AKI is an easily reversible state that is likely not associated with substantial tubular injury and therefore NGAL release. Using AKIN criteria, both transient and sustained AKI are classified as AKI even though our data demonstrate that they are possibly different entities.

Analysis of urine biomarkers for early determination of acute kidney injury in non-septic and non-asphyxiated critically ill preterm neonates

OBJECTIVE

We designed the present study to test the hypothesis that urinary biomarkers might predict acute kidney injury (AKI) development in non-septic and non-asphyxiated critically ill preterm infants. We evaluated urine (u) sistatin-C (uCys-C), kidney injury molecule-1 (uKIM-1) and neutrophil gelatinase associate lipocaline (uNGAL) as markers of AKI.

METHODS

Sixty-four preterm infants with gestational age between 28 and 32 weeks were included in this study. Biomarkers were measured on day of life (DOL) 1, 3, and 7.

RESULTS

uNGAL levels in the AKI group were significantly higher than in no-AKI group on DOL 1, 3 and 7 (p = 0.016, p = 0.007 and p = 0.0014, respectively).

CONCLUSIONS

uNGAL is sensitive, early, and noninvasive AKI biomarkers, increasing significantly in non-septic and non-asphyxiated critically ill preterm neonates.

Comparison of Two Methods for Determination of NGAL Levels in Urine: ELISA and CMIA

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a new useful biomarker for the early diagnosis of acute kidney injury. The aim of the study was to compare two analytical methods for measurement of urinary NGAL: enzyme-linked immunosorbent assay (ELISA) and chemiluminescent microparticle immunoassay (CMIA).

METHODS

Two assays were used to measure urinary NGAL: ELISA kit (R&D Systems) and ARCHITECT Urine NGAL (Abbott Laboratories). The study material was the urine obtained from 30 healthy subjects (mean age 56.4 ± 15.2).

RESULTS

The median value and interquantile range of urinary NGAL in the studied group measured by ELISA (R&D Systems) were 3.5 ng/ml (1.2; 6.6) and by CMIA (ARCHITECT Urine NGAL assay, Abbott Diagnostics) were 4.4 ng/ml (1.9; 9.4). Levels of urinary NGAL obtained by CMIA were significantly higher than by ELISA. There was a significant positive correlation between the concentration of urinary NGAL determined by both methods (r = 0.8625, P < 0.01).

CONCLUSION

The comparison of individual data obtained by ELISA and CMIA should be taken with care. From laboratory's point of view, ELISA is less expensive than CMIA method for the determination of NGAL in urine. However, CMIA method allows rapid determination of urinary NGAL concentration through automated assay.

The efficacy of theophylline in preventing cisplatin-related nephrotoxicity in patients with cancer

OBJECTIVE

Cisplatin is a potent antineoplastic agent used and its major limiting side effect is nephrotoxicity. The aims of the study are early detection of acute kidney injury (AKI) with biomarkers and investigation of the potential nephron-protective effects of theophylline.

METHODS

Glomerular filtration rates (GFR), neutrophil gelatinase-associated lipocalin (NGAL), cystatin C were measured at 5th day of treatment in all of the patients. In addition, these parameters were measured repeatedly after the administration of cisplatin, at 2nd hour, 5th and 20th days.

PATIENTS

Sixty patients who are planned to receive cisplatin for the first time were included in the study. Patients were divided into two groups as Group 1 (n = 30) (standard treatment arm) and Group II (n = 30) (theophylline arm).

RESULTS

In both groups after the administration of cisplatin, GFR showed a significant decrease within time (p = 0.006). Urine NGAL levels were significantly high after 2 h of cisplatin administration (p < 0.001), no significant difference was observed between groups. However, when the time*group effects were considered together, higher NGAL levels were detected in the group not receiving theophylline (p = 0.025). After 5 days of cisplatin administration, urine protein levels were significantly higher in both groups (p < 0.001).

CONCLUSION

Results showed that urine NGAL level is a superior biomarker compared to serum creatinine and serum cystatin C in the detection of early AKI. Theophylline was found not to bring a complete protection for the kidneys, but less nephrotoxicity was developed when compared to the group not receiving theophylline.

Role of plasma neutrophil gelatinase-associated lipocalin as an emerging biomarker of acute renal failure following kidney transplantation and its correlation with plasma creatinine

Introduction: Graft function early after kidney transplantation is an important parameter in determining the outcome of operation. Urinary and plasma neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin protein family, has been advocated as a sensitive, early biomarker for predicting early renal graft after transplantation. The functions of NGAL appears to be expressed in stress conditions and in tissues undergoing involution. It rapidly accumulates in the kidney tubules and urine after nephrotoxic and ischemic insults.

Objectives: This study aimed to examine the prognostic role of NGAL early after renal transplantation.

Patients and Methods: A total of 37 kidney recipients were enrolled from a teaching centre in Tabriz within a 6-month period of time. Plasma NGAL was measured immediately before and at 6 and 12 hours post-transplantation. Changes of serum creatinine were documented daily within the first week post-operation. Acute kidney injury (AKI)/graft rejection during the first week after transplantation was the outcome variable.

Results: There were 22 males (59.5%) and 15 females (40.5%) with the mean age of 34.93 ± 14.97 years (range: 12-59) in the study group. AKI/graft rejection developed in 12 patients (32.4%). The mean post-transplantation plasma NGAL levels and serum creatinine at all time points were significantly higher in patients with AKI/graft rejection. The best prognostic role was found for plasma NGAL at 12 hours (sensitivity = 100%, specificity = 92%; cut-off value = 309 ng/ml), far better than the prognostic accuracy of corresponding serum creatinine (sensitivity = 66.7%, specificity = 61.9%).

Conclusion: Plasma NGAL, particularly 12 hours after transplantation, is a very sensitive and specific biomarker for predicting acute renal injury.

Body fluid peptide and protein signatures in diabetic kidney diseases

Body fluid protein-based biomarkers carry the hope of improving patient management in diabetes by enabling more accurate and earlier detection of diabetic kidney disease (DKD), but also of defining the most suitable therapeutic targets. We present the data on some of the best studied individual protein markers in body fluids and conclude that their potential in clinical application for assessing DKD is moderate. Proteome-based approaches aiming at the identification of panels of body fluid biomarkers might be a valid alternative. We discuss the past (first) clinical proteomics studies in DKD, stressing their drawbacks but also the lessons that could be learned from them, as well as the more recent studies that have a potential for actual clinical implementation. We also highlight relevant issues and current problems associated with clinical proteomics from discovery towards application, and give suggestions for solutions that may help guiding proteomic studies, thereby removing some of the current hurdles for implementation of potentially beneficial results.

Fish Oil-Based Fat Emulsion Reduces Acute Kidney Injury and Inflammatory Response in Antibiotic-Treated Polymicrobial Septic Mice

Acute kidney injury (AKI) is a common complication in sepsis. This study compared the effects of a fish oil-based with a mixed oil fat emulsion on remote renal injury in an antibiotic-treated septic murine model. Mice were randomly assigned to a normal control (NC) group and three septic groups. Sepsis was induced by cecal ligation and puncture (CLP). The antibiotic was injected intraperitoneally (IP) after CLP and then daily till the time of sacrifice. Three hours after antibiotic treatment, one of the septic groups was injected IP with a fish oil-based emulsion (FO), while the other two groups were given either a mixed oil emulsion (MO) or saline (SC). The septic groups were further divided into two separate time groups, with blood and kidneys samples collected at 24 h or 72 h post-CLP. The results showed that sepsis leads to the activation of neutrophils, T helper (Th)1/Th-2/Th-17 and Treg cells (p < 0.05). Plasma NGAL and mRNA expressions of renal MyD88 and TLR4 were also enhanced (p < 0.05). Compared to the SC group, the group given the fish oil-based emulsion had decreased plasma NGAL by 22% and Treg by 33%. Furthermore, renal gene expressions of MyD88 and TLR4 reduced by 46% and 62%, respectively, whereas heat shock protein 70 and peroxisome proliferator-activated receptor-γ increased by 158% and 69%, respectively (p < 0.05), at Day 3 after CLP. These results suggest that administration of a fish oil-based emulsion has favorable effects, maintaining blood T cell percentage, downregulating Treg expression, attenuating systemic and local inflammation and offering renal protection under conditions of antibiotic-treated polymicrobial sepsis.

Drug-induced renal damage in preterm neonates: state of the art and methods for early detection

Only a small fraction of drugs widely used in neonatal intensive care units (NICU) are specifically authorized for this population. Even if unlicensed or off-label use is necessary, it is associated with increased adverse drug reactions, which must be carefully weighed against expected benefits. In particular, renal damage is frequent among preterm babies, and is considered a predisposing factor for the development of chronic kidney disease in adulthood. Apart from specific conditions affecting premature neonates (e.g. respiratory distress syndrome, perinatal asphyxia), drugs play an important role in impairing renal function because of well-known nephrotoxicity and/or interaction with renal developmental factors. From a review of the available studies on drug use in NICU patients, we identified and described the most commonly administered drugs that are correlated to renal damage. Early detection of kidney injury is becoming an essential aspects for clinicians because of the limited number of biomarkers applicable in the neonatal population. Postnatal changes of biochemical processes that influence pharmacokinetic and pharmacodynamic aspects need to be further investigated in order to better understand the mechanisms of drug toxicity in this population. The most promising strategies for dose adjustment and therapeutic schemes are discussed. The purpose of this review was to describe current knowledge on drug use among premature babies and their implication in kidney injury development, as well as to highlight available strategies for early detection of renal damage.

Interleukin 18 and neutrophil-gelatinase associated lipocalin in assessment of the risk of contrast-induced nephropathy in children

The aim of the study was to determine the usefulness of interleukin 18 (IL-18) and neutrophil-gelatinase associated lipocalin (NGAL) in the risk assessment of contrast nephropathy in children. The study included patients among whom radiological examinations were performed using intravascular contrast agent. The material consisted of 33 children (19 girls, 14 boys) aged 6.37 ±5.41 years. 20/33 (61%) of patients had hydronephrosis, 9/33 (27%) had other urinary tract defects referred as “no hydronephrosis” and 4/33 (12%) had urolithiasis. NGAL determination was performed with the use of Human Lipocalin-2 / NGAL Immunoassay. To determine the concentration of human IL-18 an ELISA Kit (MBL International Corporation) was used. There were no statistically significant differences in the concentrations of NGAL and IL-18 in serum determined before the procedure, and after the administration of contrast agent. Concentrations of NGAL and IL-18 were determined in urine three times: before the procedure, 2-4 hours after administration of the contrast agent, and 48 hours after the performed procedure. The analysis showed that the concentration of IL-18 and NGAL in urine did not differ significantly in three consecutive preformed measurements. The study has also found no statistically significant differences between serum creatinine before and 48 hours after injection of contrast. Implementation of new biomarkers such as NGAL and IL-18 expands the possibilities of renal function assessment in children undergoing radiological procedures using contrast agents. In examined children with normal or slightly impaired renal function they did not demonstrate the risk of contrast nephropathy.

Urinary NGAL in patients with and without acute kidney injury in a cardiology intensive care unit

Objective

To assess the diagnostic and prognostic efficacy of urine neutrophil gelatinase-associated lipocalin in patients admitted to an intensive care unit.

Methods

Longitudinal, prospective cohort study conducted in a cardiology intensive care unit. The participants were divided into groups with and without acute kidney injury and were followed from admission to the intensive care unit until hospital discharge or death. Serum creatinine, urine output and urine neutrophil gelatinase-associated lipocalin were measured 24 and 48 hours after admission.

Results

A total of 83 patients admitted to the intensive care unit for clinical reasons were assessed, most being male (57.8%). The participants were divided into groups without acute kidney injury (N=18), with acute kidney injury (N=28) and with severe acute kidney injury (N=37). Chronic diseases, mechanical ventilation and renal replacement therapy were more common in the groups with acute kidney injury and severe acute kidney injury, and those groups exhibited longer intensive care unit stay and hospital stay and higher mortality. Serum creatinine did not change significantly in the group with acute kidney injury within the first 24 hours of admission to the intensive care unit, although, urine neutrophil gelatinase-associated lipocalin was high in the groups with acute kidney injury and severe acute kidney injury (p<0.001). Increased urine neutrophil gelatinase-associated lipocalin was associated with death.

Conclusion

An increase in urine neutrophil gelatinase-associated lipocalin precedes variations in serum creatinine in patients with acute kidney injury and may be associated with death.

Effect of Kidney Function on Drug Kinetics and Dosing in Neonates, Infants, and Children

Neonates, infants, and children differ from adults in many aspects, not just in age, weight, and body composition. Growth, maturation and environmental factors affect drug kinetics, response and dosing in pediatric patients. Almost 80% of drugs have not been studied in children, and dosing of these drugs is derived from adult doses by adjusting for body weight/size. As developmental and maturational changes are complex processes, such simplified methods may result in subtherapeutic effects or adverse events. Kidney function is impaired during the first 2 years of life as a result of normal growth and development. Reduced kidney function during childhood has an impact not only on renal clearance but also on absorption, distribution, metabolism and nonrenal clearance of drugs. 'Omics'-based technologies, such as proteomics and metabolomics, can be leveraged to uncover novel markers for kidney function during normal development, acute kidney injury, and chronic diseases. Pharmacometric modeling and simulation can be applied to simplify the design of pediatric investigations, characterize the effects of kidney function on drug exposure and response, and fine-tune dosing in pediatric patients, especially in those with impaired kidney function. One case study of amikacin dosing in neonates with reduced kidney function is presented. Collaborative efforts between clinicians and scientists in academia, industry, and regulatory agencies are required to evaluate new renal biomarkers, collect and share prospective pharmacokinetic, genetic and clinical data, build integrated pharmacometric models for key drugs, optimize and standardize dosing strategies, develop bedside decision tools, and enhance labels of drugs utilized in neonates, infants, and children.

Influence of Acute Kidney Injury Defined by the Pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease Score on the Clinical Course of PICU Patients

OBJECTIVE

To evaluate the predictive value of the pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease criteria for disease course severity in patients with or without acute kidney injury admitted to a PICU.

DESIGN

Retrospective cohort study.

SETTING

A 12-bed PICU at a tertiary referral center in Southern Brazil.

PATIENTS

All patients admitted to the study unit over a 1-year period.

INTERVENTIONS

A database of all eligible patients was analyzed retrospectively.

MEASUREMENTS AND MAIN RESULTS

Patients were classified by pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease score at admission and worst pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease score during PICU hospitalization. The outcomes of interest were length of PICU stay, duration of mechanical ventilation, duration of vasoactive drug therapy, and mortality. The Pediatric Index of Mortality 2 was used to assess overall disease severity at the time of PICU admission. Of 375 patients, 169 (45%) presented acute kidney injury at the time of admission and 37 developed acute kidney injury during PICU stay, for a total of 206 of 375 patients (55%) diagnosed with acute kidney injury during the study period. The median Pediatric Index of Mortality 2 score predicted a mortality rate of 9% among non-acute kidney injury patients versus a mortality rate of 16% among acute kidney injury patients (p = 0.006). The mortality of patients classified as pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease F was double that predicted by Pediatric Index of Mortality 2 (7 vs 3.2). Patients classified as having severe acute kidney injury (pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease I + F) exhibited higher mortality (14.1%; p = 0.001) and prolonged PICU length of stay (median, 7 d; p = 0.001) when compared with other patients. Acute kidney injury is a very frequent occurrence among patients admitted to PICUs.

CONCLUSIONS

The degree of acute kidney injury severity, as assessed by the pediatric-modified Risk, Injury, Failure, Loss, End-stage renal disease criteria, is a good predictor of morbidity and mortality in this population. Pediatric Index of Mortality 2 tends to underestimate mortality in pediatric patients with severe acute kidney injury.

Detection of early renal injury in children with solid tumors undergoing chemotherapy by urinary neutrophil gelatinase-associated lipocalin

Acute kidney injury (AKI) is a complication in children with solid tumors undergoing chemotherapy, as it may prevent the use of therapy protocols and also hinder the supportive and diagnostic procedures. Thus, there is an urgent requirement for early predictive biomarkers of AKI. The most promising novel AKI biomarker is neutrophil gelatinase-associated lipocalin (NGAL). The aim of the present study was to compare the predictability of NGAL as a biomarker of AKI with creatinine as a traditional biomarker in children with solid tumors under chemotherapy. The study was performed on 30 patients with different types of solid tumors (reuroblastoma, Wilms tumor, medulloblastoma, rhabdomyosarcoma and Ewing sarcoma) and 20 control subjects. Urinary NGAL (uNGAL) and serum creatinine samples were taken three times: Baseline before the beginning of the treatment, one week after chemotherapy and at the end of the chemotherapy protocol. AKI is defined as a change in creatinine level by >50% of the baseline. The creatinine level only rises to this level in the third sample, while uNGAL increases significantly in the second and third samples with percentage of change 376.8 and 698.2%, respectively, which is highly significant (P<0.001). When comparing the predictive value of serum creatinine for AKI depending on the receiver operating characteristic curve with that of uNGAL, the area under the curve (AUC) for creatinine was 0.60 with a standard error (SE) of 0.086 and 95% confidence interval (CI) between 0.432 and 0.768, while that of uNGAL was highly predictive with an AUC of 0.847, SE 0.55 and 95% CI between 0.739 and 0.955. Depending only on the creatinine level for detecting the AKI will markedly delay the diagnosis; however, uNGAL is detected earlier, and is easier and more reliable as a marker for AKI in children with solid tumors undergoing chemotherapy.

Role of urine neutrophil gelatinase-associated lipocalin in the early diagnosis of amphotericin B-induced acute kidney injury

Determination of the neutrophil gelatinase-associated lipocalin (NGAL) level can be used to detect acute kidney injury (AKI) earlier than determination of the serum creatinine (SCr) level in settings such as cardiac surgery, contrast nephropathy, and intensive care units. We hypothesized that urine NGAL (UrNGAL) would be an early biomarker of drug nephrotoxicity. To test this, we studied hemodynamically stable patients treated with amphotericin B (AmB). We measured the SCr and UrNGAL levels at the baseline and daily after initiation of AmB up to day 14 or development of AKI by the use of the SCr criterion. AKI was defined according to a Kidney Disease: Improving Global Outcomes (KDIGO) criterion (an increase in the SCr level by ≥0.3 mg/dl within 48 h or an SCr level ≥1.5 times the baseline level within 7 days). We studied 24 patients with a mean age of 48.4 ± 16.4 years. Most patients were male, and the patients received AmB (12 received AmB deoxycholate and 12 received liposomal AmB) for the treatment of leishmaniasis (91.7%). Overall, 17/24 patients fulfilled a KDIGO criterion for AKI. Peak UrNGAL levels were higher in patients with AKI than in patients without AKI and in recipients of AmB deoxycholate than in recipients of liposomal AmB. The diagnostic performance of the UrNGAL level on day 5 for the detection of AKI was moderate, with the area under the curve (AUC) being 0.68 (95% confidence interval [CI], 0.41 to 0.95). In the subgroup receiving AmB deoxycholate, however, the AUC rose to 0.89 (95% CI, 0.67 to 1.00). In a patient-level analysis, we found that AKI could be detected 3.2 days earlier by the use of the UrNGAL criterion than by the use of the SCr criterion (times to AKI by the UrNGAL and SCr criteria, 3.7 ± 2.5 versus 6.9 ± 3.3 days, respectively; P = 0.001). Future studies should evaluate if a treatment strategy oriented toward evaluation of UrNGAL levels will improve outcomes. These findings for AmB-induced AKI in leishmaniasis patients could serve as a basis for the investigation of urine biomarkers in the early detection of drug nephrotoxicity in other clinical settings.