L-FABP can be an early marker of acute kidney injury in children

Urinary L-FABP as an Early Biomarker for Pediatric Acute Kidney Injury Following Cardiac Surgery with Cardiopulmonary Bypass: A Systematic Review and Meta-Analysis

Acute kidney injury (AKI) following surgery with cardiopulmonary bypass (CPB-AKI) is common in pediatrics. Urinary liver-type fatty acid binding protein (uL-FABP) increases in some kidney diseases and may indicate CPB-AKI earlier than current methods. The aim of this systematic review with meta-analysis was to evaluate the potential role of uL-FABP in the early diagnosis and prediction of CPB-AKI. Databases Pubmed/MEDLINE, Scopus, and Web of Science were searched on 12 November 2023, using the MeSH terms "Children", "CPB", "L-FABP", and "Acute Kidney Injury". Included papers were revised. AUC values from similar studies were pooled by meta-analysis, performed using random- and fixed-effect models, with p < 0.05. Of 508 studies assessed, nine were included, comprising 1658 children, of whom 561 (33.8%) developed CPB-AKI. Significantly higher uL-FABP levels in AKI versus non-AKI patients first manifested at baseline to 6 h post-CPB. At 6 h, uL-FABP correlated with CPB duration (r = 0.498, p = 0.036), postoperative serum creatinine (r = 0.567, p < 0.010), and length of hospital stay (r = 0.722, p < 0.0001). Importantly, uL-FABP at baseline (AUC = 0.77, 95% CI: 0.64-0.89, n = 365), 2 h (AUC = 0.71, 95% CI: 0.52-0.90, n = 509), and 6 h (AUC = 0.76, 95% CI: 0.72-0.80, n = 509) diagnosed CPB-AKI earlier. Hence, higher uL-FABP levels associate with worse clinical parameters and may diagnose and predict CPB-AKI earlier.

Acute kidney injury in pediatrics: an overview focusing on pathophysiology

Acute kidney injury (AKI) is defined as an abrupt decline in glomerular filtration rate, with increased serum creatinine and nitrogenous waste products due to several possible etiologies. Incidence in the pediatric population is estimated to be 3.9 per 1,000 hospitalizations, and prevalence among children admitted to intensive care units is 26.9%. Despite being a condition with important incidence and morbimortality, further evidence on pathophysiology and management among the pediatric population is still lacking. This narrative review aimed to summarize and discuss current data on AKI pathophysiology in the pediatric population, considering all the physiological particularities of this age range and common etiologies. Additionally, we reported current diagnostic tools, novel biomarkers, and newly proposed medications that have been studied with the aim of early diagnosis and appropriate treatment of AKI in the future.

Derivation and validation of urinary TIMP-1 for the prediction of acute kidney injury and mortality in critically ill children

Background

Acute kidney injury (AKI) is associated with high morbidity and mortality. Multiple urinary biomarkers have been identified to be associated with the prediction of AKI and outcomes. However, the accuracy of these urinary biomarkers for AKI and associated outcomes has not been clearly defined, especially in heterogeneous populations. The aims of the study were to compare the ability of 10 existing or potential urinary biomarkers to predict AKI and pediatric intensive care unit (PICU) mortality and validate urinary tissue inhibitor of metalloproteinases-1 (uTIMP-1) as a better biomarker for early prediction in heterogeneous critically ill children.

Methods

A derivation-validation approach with separate critically ill cohorts was designed. We first conducted a prospective cohort study to determine the ability of 10 urinary biomarkers serially measured in 123 children during the first 7 days of PICU stay to predict AKI and PICU mortality (derivation study) and further validated the better biomarker of uTIMP-1 in a separate cohort of 357 critically ill children (validation study). AKI diagnosis was based on KDIGO classification with serum creatinine and urine output. PICU mortality was defined as all-cause mortality.

Results

In the derivation cohort, 17 of 123 (13.8%) children developed AKI stage 3 or died during the PICU stay, and both the initial and peak uTIMP-1 displayed the highest AUCs of 0.87 (0.79–0.94) and 0.90 (0.84–0.96), respectively, for predicting AKI stage 3 or death. In the validation cohort, 78 of 357 (21.8%) developed AKI during the first week after admission, and 38 (10.6%) died during the PICU stay. The initial uTIMP-1 level was validated to be independently associated with AKI (AOR = 2.88, 95% CI 1.97–4.21), severe AKI (AOR = 2.62, 95% CI 1.78–3.88), AKI stage 3 (AOR = 2.94, 95% CI 1.84–4.68) and PICU mortality (AOR = 1.92, 95% CI 1.11–3.30) after adjustment for potential confounders. The predictive values of uTIMP-1 for AKI, severe AKI, AKI stage 3 and PICU mortality were 0.80 (0.74–0.86), 0.83 (0.77–0.89), 0.84 (0.77–0.92) and 0.83 (0.76–0.89), respectively.

Conclusions

Urinary TIMP-1 levels have been identified and validated to be independently associated with AKI and PICU mortality in independent prospective cohorts and may be an early potential indicator of AKI and PICU mortality in critically ill children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03302-0.

Use of non-conventional biomarkers in the early diagnosis of acute kidney injury in preterm newborns with sepsis

Acute kidney injury (AKI) is a common finding in Neotatal Intensive Care Units (NICU). Sepsis is one the main causes of AKI in preterm newborns. AKI has been associated with significant death rates. Early detection of the condition is the first step to improving prevention, treatment, and outcomes, while decreasing length of hospitalization, care costs, and morbimortality. AKI may progress to chronic kidney disease (CKD), a condition linked with dialysis and greater risk of cardiovascular disease. This review article aims to discuss cases of AKI in preterm newborns with sepsis, the use of biomarkers in lab workup, and the use of non-conventional biomarkers for the early identification of AKI.

Longitudinal Changes in Serum Creatinine Levels and Urinary Biomarkers in Late Preterm Infants during the First Postnatal Week: Association with Acute Kidney Injury and Treatment with Aminoglycoside

We aimed to determine the incidence of acute kidney injury (AKI) and longitudinal changes in SCr levels and urinary biomarkers associated with AKI and aminoglycoside (AG) medication during the first week of life of late preterm infants. Urine biomarkers and SCr were measured in thirty late preterm infants on days one, two, five, and seven postnatal. Urine biomarkers included neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1 (MCP-1), epidermal growth factor (EGF), Tamm-Horsfall glycoprotein (THP), and liver fatty-acid-binding protein (L-FABP). Gestational age was positively correlated with SCr levels at birth, but inversely correlated with SCr levels at day five and day seven. Eighteen (60%) infants had stage 1 AKI, and twenty (67%) infants were treated with AGs. Infants with AKI had lower gestational age and lower birth weight than those without AKI. Urinary biomarkers adjusted according to uCr levels in infants with AKI were not statistically different from those in infants without AKI. There were no significant differences in incidence of AKI, and SCr levels during and after cessation of AG treatment. The uMCP-1/Cr ratio at days five and seven was higher in infants treated with AG than in non-treated infants.

Novel Urinary Biomarkers for Acute Kidney Injury and Prediction of Clinical Outcomes After Pediatric Cardiac Surgery

Acute kidney injury (AKI) is a serious complication of pediatric cardiac surgery, with high morbidity and mortality. We aimed to evaluate the perioperative risk factors for AKI, and the validity of novel diagnostic urinary biomarkers after pediatric cardiac surgery. We analyzed 103 consecutive pediatric patients (≤ 18 years old), who underwent cardiac surgery. AKI was defined by ≥ 50% increase in serum creatinine levels from baseline. Urinary liver-type fatty acid binding protein (L-FABP) and neutrophil gelatinase-associated lipocalin (NGAL) were measured postoperatively at the intensive care unit (ICU) admission, subsequently at 4, 12, and 24 h. Areas under the receiver-operating characteristic curves (AUC) were calculated at each assessment time. AKI had developed in 47 patients (45.6%) by the second postoperative day. Univentricular status, aortic cross-clamping time, and intraoperative fluid balance were independently associated with AKI (p = 0.02, 0.01 and 0.01, respectively). Urinary L-FABP and NGAL were significantly higher in the AKI group at each point (p < 0.05). The predictive abilities of both biomarkers (AUC = 0.78-0.90) at ICU admission and 4 h after were especially high. The patients with L-FABP greater than the cutoff value at ICU admission and 4 h after ICU admission had significantly longer intubation and hospitalization periods (p < 0.05). Those with elevated NGAL levels at admission, and 4 h and 24 h after ICU admission, had significantly longer intubation, ICU stay, and hospitalization (p < 0.05). L-FABP and NGAL can be useful biomarkers for detecting early AKI after pediatric cardiac surgery and predicting adverse clinical outcomes.

Urinary L-FABP as a marker of vesicoureteral reflux in children: could it also have a protective effect on the kidney?

PURPOSE

Liver-type fatty acid-binding protein is a small cytoplasmic protein which is expressed in the human renal proximal tubular epithelium and synthesized in response to renal tubular injury. The aim of the present study was to investigate the importance of urinary liver-type fatty acid-binding protein levels in children who diagnosed with vesicoureteral reflux.

METHODS

Fifty-six patients with vesicoureteral reflux and 51 healthy controls were enrolled to the study. The cases were divided into three groups as follows: group A-the controls, group B-the patients who had renal parenchymal scarring and group C-the patients who had no scarring. Urinary liver-type fatty acid-binding protein was measured by enzyme-linked immunosorbent assay method. Creatinine was measured by modified Jaffe method, protein was measured by turbidimetric method, and urine density was determined by using the "falling drop" procedure.

RESULTS

Urinary liver-type fatty acid-binding protein and urinary liver-type fatty acid-binding protein/creatinine levels were significantly higher in the whole patient group than in the controls (p = 0.016, 0.006). Significant differences were also determined by comparing the three groups (p = 0.015, 0.014), and those levels were found as significantly higher in group C.

CONCLUSION

Urinary liver-type fatty acid-binding protein was considered to be helpful for the diagnosis of vesicoureteral reflux, and also it might contribute to understand the mechanisms causing scar tissue formation especially for the patients who had vesicoureteral reflux. Further clinical and experimental investigations are required to elucidate in detail the physiology of liver-type fatty acid-binding protein.

Urinary L-FABP as a mortality predictor in <5-year-old children with sepsis in Bangladesh

BACKGROUND

Although sepsis is often associated with high mortality in severely malnourished children, data are very limited on appropriate diagnostic tools to predict mortality. We examined the role of urinary liver-type fatty acid-binding protein (L-FABP) in children <5 years old with sepsis who died.

METHODS

This prospective observational study was conducted at the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh. Children aged 6-59 months admitted with sepsis from April 2010 to December 2011 were enrolled. Comparison of clinical and laboratory characteristics was made between children who survived (n = 83) and those who did not survive (n = 22).

RESULTS

On multiple Poisson regression analysis, after adjusting for potential confounders such as mid-upper arm circumference < 115 mm, plasma albumin < 2.5 g/dL, potassium > 5.0 mmol/L, and blood urea nitrogen > 20 mg/dL on admission, first urine L-FABP ≥ 370 ng/mL (relative risk [RR], 2.76; 95%CI: 1.22-6.25), weight-for-length/height z score < -3 (RR, 2.54; 95%CI: 1.26-5.09), capillary refilling time > 2.0 s (RR, 5.16; 95%CI: 1.46-18.3), and sodium > 160 mmol/L (RR, 2.72; 95%CI: 1.07-6.90) were identified as significant risk factors of mortality in children with sepsis. Diagnostic performance of first urine L-FABP was analyzed using receiver operating characteristic curve, and the area under the curve was 0.647 (95%CI: 0.500-0.795).

CONCLUSION

Urinary L-FABP may be a useful predictor of mortality in septic children. Urinary examination is non-invasive and easy to apply at the bedside.

Response of urinary liver-type fatty acid-binding protein to contrast media administration has a potential to predict one-year renal outcome in patients with ischemic heart disease

Urinary liver-type fatty acid-binding proteins (uL-FABP) have recently been recognized as a useful biomarker for predicting contrast-induced nephropathy. Although accumulating studies have evaluated short-term outcomes, its prognostic value for long-term renal prognosis in patients undergoing coronary angiography (CAG) has not been fully examined. This study aimed to evaluate the predictive value of uL-FABP for long-term renal outcome in patients with ischemic heart disease (IHD). Consecutive 24 patients with impaired renal function (serum creatinine >1.2 mg/dL) who underwent CAG were enrolled. uL-FABP was measured before CAG, 24 and 48 h after CAG. The changes in estimated glomerular filtration rate (eGFR) throughout CAG and at 1 year later were compared with the uL-FABP levels. The patients with a greater decrease in eGFR 1 year later had higher uL-FABP levels at all points, but only the value at 48 h after CAG reached statistical significance (lower vs. higher decreased eGFR group, 4.61 ± 3.87 vs. 17.71 ± 12.96; P < 0.01). Measurement of uL-FABP at 48 h after CAG (48h-uL-FABP) showed better correlation with the change in eGFR (pre-CAG uL-FABP vs. 48h-uL-FABP: R = 0.27, P = 0.20 vs. R = 0.65, P < 0.01). Moreover, the high-pre and high-48h-uL-FABP group showed a significantly larger decrease in eGFR compared with the high-pre and low-48h-uL-FABP group (change in eGFR; 8.12 ± 4.06 vs. 1.25 ± 2.23 mL/min/1.73 m2, P < 0.01), although the baseline eGFR levels were similar between these two groups. In this pilot study, measurement of uL-FABP levels at 48 h after CAG may be useful in detecting renal damage, and in predicting 1-year renal outcome in IHD patients undergoing CAG.

Urinary biomarkers and acute kidney injury in children: the long road to clinical application

Pediatric acute kidney injury is rising with the advances in technology available for children with chronic conditions or those who are critically ill. Serum creatinine and urine output, traditional markers of renal function, often allow only delayed and unreliable diagnosis of acute kidney injury. Biomarker development in pediatric patients with low disease prevalence is challenging (small cohorts, few analyzable events). In this issue of Pediatric Nephrology, Ivanisevic and colleagues report that urinary liver-type fatty-acid-binding protein (L-FABP) can be used for early identification of pediatric acute kidney injury in a small cohort undergoing cardiac surgery. Addition of the biomarker resulted in an improvement in early diagnosis compared with a clinical model (age, gender, body weight, cardiopulmonary bypass duration, and aortic clamp time). It is noteworthy that the preoperative clinical model performed excellently in predicting postsurgery pediatric acute kidney injury. Further work is needed before this or other novel biomarkers (alone or in combination) can be implemented in clinical practice. Large-scale observational studies are needed to test these biomarkers against hard clinical endpoints, independent of serial measurements of serum creatinine concentrations. Prospective randomized interventional trials using exclusively high biomarker levels to define acute kidney injury should demonstrate improved clinical outcomes.

Organic anion transporter 5 (Oat5) renal expression and urinary excretion in rats treated with cisplatin: a potential biomarker of cisplatin-induced nephrotoxicity

Cisplatin is one of the most potent chemotherapeutic antitumor drugs used in the treatment of a wide range of solid tumors. Its primary dose-limiting side effect is nephrotoxicity. The organic anion transporter 5 (Oat5) is exclusively localized in the kidney. Oat5 urinary excretion was recently proposed as a potential early biomarker of acute kidney injury (AKI). The aim of this study was to evaluate Oat5 renal expression and its urinary excretion in rats exposed to different doses of cisplatin, in comparison with traditional markers of renal injury, like renal histology, creatinine and urea plasma levels, creatinine clearance, protein and glucose urinary levels and urinary alkaline phosphatase (AP) activity. Male Wistar rats were treated with a single injection of cisplatin at different doses of 1, 2, 5 and 10 mg/kg b.w., i.p. (Cis1, Cis2, Cis5 and Cis10, n = 4, respectively) and experiments were carried out 48 h after cisplatin administration. The renal expression of Oat5 was evaluated by immunohistochemistry and Western blotting. Oat5 abundance, AP activity, creatinine, glucose and proteins were assayed in urine. Creatinine clearance and creatinine and urea plasma levels were also evaluated. In this experimental model, plasma urea and creatinine levels, creatinine clearance, AP urinary activity and protein and glucose urinary levels were significantly modified only at the highest cisplatin dose of 10 mg/kg b.w., i.p., as compared to control rats. In contrast, Oat5 urinary abundance was increased in a dose-related manner after the administration of cisplatin. Oat5 urinary abundance was elevated at a dose as low as 1 mg/kg b.w., i.p., implying renal perturbation, when no modifications of traditional markers of renal injury are yet observed. Oat5 renal expression was decreased in a dose-related manner, both in homogenates and apical membranes from cisplatin-treated kidneys. The increase in urinary Oat5 excretion might explain the decrease in the amount of Oat5 molecules in the renal tubule cells. Hence, the preclinical animal results showed in this work propose that Oat5 urinary excretion might potentially serve as a non-invasive early biomarker of cisplatin-induced AKI.