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

Gut microbiota and neonatal acute kidney injury biomarkers

One of the most frequent issues in newborns is acute kidney injury (AKI), which can lengthen their hospital stay or potentially raise their chance of dying. The gut-kidney axis establishes a bidirectional interplay between gut microbiota and kidney illness, particularly AKI, and demonstrates the importance of gut microbiota to host health. Since the ability to predict neonatal AKI using blood creatinine and urine output as evaluation parameters is somewhat constrained, a number of interesting biomarkers have been developed. There are few in-depth studies on the relationships between these neonatal AKI indicators and gut microbiota. In order to gain fresh insights into the gut-kidney axis of neonatal AKI, this review is based on the gut-kidney axis and describes relationships between gut microbiota and neonatal AKI biomarkers.

Urine acute kidney injury biomarkers in extremely low gestational age neonates: a nested case control study of 21 candidate urine biomarkers

BACKGROUND

Acute kidney injury (AKI) is common and is associated with poor clinical outcomes in premature neonates. Urine biomarkers hold the promise to improve our understanding and care of patients with kidney disease. Because kidney maturation and gender can impact urine biomarker values in extremely low gestational age neonates (ELGANs), careful control of gestational age (GA) and time is critical to any urine biomarker studies in neonates.

METHODS

To improve our understanding of the potential use of urine biomarkers to detect AKI during the first postnatal weeks, we performed a nested case-control study to evaluate 21 candidate urine AKI biomarkers. Cases include 20 ELGANs with severe AKI. Each case was matched with 2 controls for the same GA week (rounded down to the nearest week), gender, and birth weight (BW) (± 50 g).

RESULTS

Urine cystatin C, creatinine, ghrelin, fibroblast growth factor-23 (FGF23), tissue metalloproteinase 2 (TIMP2) and vascular endothelial growth factor A (VEGFa) concentrations were higher in ELGANs with early severe AKI compared to matched control subjects without AKI. Urine epidermal growth factor (EGF) and uromodulin (UMOD) concentrations are lower in cases than controls. Interleukin (IL)-15 was lower on day 1, but higher on day 8 in cases than controls; while VEGFa was lower on day 1, but higher on day 5 in cases than controls.

CONCLUSION

Urine biomarkers hold the promise to improve our ability to reliably detect kidney injury. Interventional studies are needed to determine the biomarkers' ability to predict outcomes, enhance AKI phenotypes, and improve timely interventions which can prevent the sequalae of AKI in ELGANs. A higher resolution version of the Graphical abstract is available as Supplementary information.

Predictive value of neutrophil gelatinase-associated lipocalin in children with acute kidney injury: A systematic review and meta-analysis

Purpose

Neutrophil gelatin lipase carrier protein (NGAL) has been used as an early biomarker to predict acute kidney injury (AKI). However, the predictive value of NGAL in urine and blood in children with acute kidney injury in different backgrounds remains unclear. Therefore, we conducted this systematic review and meta-analysis to explore the clinical value of NGAL in predicting AKI in children.

Methods

Computerized databases were searched for relevant the studies published through August 4th, 2022, which included PUBMED, EMBASE, COCHRANE and Web of science. The risk of bias of the original included studies was assessed by using the Quality Assessment of Studies for Diagnostic Accuracy (QUADA-2). At the same time, subgroup analysis of these data was carried out.

Results

Fifty-three studies were included in this meta-analysis, involving 5,049 patients, 1,861 of whom were AKI patients. The sensitivity and specificity of blood NGAL for predicting AKI were 0.79 (95% CI: 0.69-0.86) and 0.85 (95% CI: 0.75-0.91), respectively, and SROC was 0.89 (95% CI: 0.86-0.91). The sensitivity and specificity of urine NGAL for predicting AKI were 0.83 (95% CI: 0.78-0.87) and 0.81 (95% CI: 0.77-0.85), respectively, and SROC was 0.89 (95% CI: 0.86-0.91). Meanwhile, the sensitivity and specificity of overall NGAL (urine and blood NGAL) for predicting AKI in children were 0.82 (95% CI: 0.77-0.86) and 0.82 (95% CI: 0.78-0.86), respectively, and SROC was 0.89 (95% CI: 0.86-0.91).

Conclusion

NGAL is a valuable predictor for AKI in children under different backgrounds. There is no significant difference in the prediction accuracy between urine NGAL and blood NGAL, and there is also no significant difference in different measurement methods of NGAL. Hence, NGAL is a non-invasive option in clinical practice. Based on the current evidence, the accuracy of NGAL measurement is the best at 2 h after cardiopulmonary bypass (CPB) and 24 h after birth in asphyxiated newborns.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022360157.

Serum and urinary biomarkers to predict acute kidney injury in premature infants: a systematic review and meta-analysis of diagnostic accuracy

BACKGROUND

Premature infants are at high risk for acute kidney injury (AKI) and current diagnostic criteria are flawed. The objective of this study was to determine the diagnostic accuracy of urine and serum biomarkers not currently used in routine clinical practice to predict AKI in premature infants.

METHOD

A systematic review was performed that followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies (PRISMA-DTA). Data were extracted on the diagnostic accuracy of AKI biomarkers using serum creatinine or urine output as the reference standard. Quality and validity were assessed using modified Standards for Reporting Diagnostic Accuracy (STARD) criteria.

RESULTS

We identified 1024 articles, with 15 studies (791 infants) eligible for inclusion. Twenty-seven biomarkers were identified including serum cystatin C and urinary neutrophil gelatinase-associated lipocalin (uNGAL), osteopontin, kidney injury molecule-1, epidermal growth factor, and protein S100-P. However, many were only reported by one study each. A meta-analysis could only be conducted on uNGAL (288 infants from 6 studies) using a hierarchical, random-effects logistic-regression model. uNGAL had a summary sensitivity of 77% (95% CI 58-89%), specificity of 76% (95% CI 57-88%) and AUC-SROC of 0.83 (95% CI 0.80-0.86) for the diagnosis of AKI. By utilising uNGAL, the post-test probability of AKI increased to 52% (95% CI 37-66%) with a positive test and decreased to 9% (95% CI 5-16%) with a negative test if the pre-test probability was 25%.

CONCLUSION

uNGAL shows promise as a diagnostically accurate biomarker for AKI in premature infants.

The Effect of a Short Course of Tocolytic Indomethacin on Urinary Biomarkers in Premature Infants

OBJECTIVE

The aim of this study was to determine the effects of a 2-day prenatal course of indomethacin on the premature kidney as reflected by serum creatinine and urinary biomarkers.

STUDY DESIGN

Urine of infants ≤32 weeks was collected for the first 14 days and analyzed for cystatin C, neutrophil gelatinase-associated lipocalin, osteopontin, β2 microglobulin, epidermal growth factor, uromodulin, and microalbumin. Bivariate analysis compared serum creatinine and biomarkers of exposed (INDO) and unexposed (CONT) subjects.

RESULTS

Fifty-seven infants (35 CONT and 22 INDO) were studied. The cohorts were similar in gestational age, birthweight, race, gender, nephrotoxic medication exposure, and Apgar's scores. CONT had more dopamine exposure and included more pre-eclamptic mothers (p = 0.005). No difference in creatinine-based acute kidney injury or the log transformed mean, maximum, and minimum values of urinary biomarkers was detected.

CONCLUSION

Our findings suggest that a short course of tocolytic indomethacin does not result in neonatal acute kidney injury.

KEY POINTS

· A short prenatal course of indomethacin does not result in neonatal acute kidney injury (AKI).. · Urinary EGF might have a promising role as a more sensitive biomarker for early detection of AKI in premature infants..

Acute kidney injury in premature and low birth weight neonates: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is common and it is associated with poor clinical outcomes in premature and low birth weight neonates. This systematic review and meta-analysis was performed to summarize the literature and evaluate the prevalence, risk factors, and mortality of premature and low birth weight neonates with AKI.

METHODS

A systematic search in PubMed, Embase, and the Cochrane Library was performed. Studies on the prevalence, risk factors, diagnosis, and outcomes of acute kidney injury in preterm neonates and neonates with low birth weight were included and analyzed.

RESULTS

Fifty articles of 10,744 patients were included in this study. The overall rate of AKI from the pooled results of all patients was 25% (95% CI 20-30%) with heterogeneity among studies (I² = 97%; P < 0.01). Patients with AKI had significantly higher rate of mortality than patients without AKI (odds ratio (OR) = 7.13; 95% CI 5.91-8.60; P < 0.01).

CONCLUSIONS

AKI was prevalent and was associated with high mortality rate among preterm and low birth weight neonates.

The influence of hyperbilirubinemia on indexes of kidney function in neonates

BACKGROUND

To study the influence of hyperbilirubinemia on indexes of neonatal kidney function.

METHODS

A prospective cohort study was conducted September 2019 to March 2020 in Neonatology Department of Xuzhou Central Hospital. Neonates with gestational age ≥ 35 weeks and aged ≤ 7 days were included and divided into mild, moderate, and severe groups according to total serum bilirubin level. Epidemiologic and demographic data and daily urine output were recorded. Total serum bilirubin, serum creatinine, serum cystatin C, serum neutrophil gelatinase-associated lipocalin (NGAL), urine NGAL, and kidney injury molecule-1 were tested before and 12~18 h after phototherapy. Parameters of kidney function were compared between groups.

RESULTS

Fifty-three, 52, and 49 neonates were included in the mild, moderate, and severe groups, respectively. Urine NGAL was higher in severe (1.36 ± 0.24 μg/L) compared to moderate (1.22 ± 0.19 μg/L) and mild groups (1.16 ± 0.19 μg/L), and differences were statistically significant (P = 0.004 and < 0.001, respectively). Urine NGAL was not significantly different between moderate and mild groups (P > 0.05). No significant differences in other kidney function indexes were observed between the three groups (all P > 0.05). Significant reduction in urine NGAL levels 12~18 h after stopping phototherapy was found in severe group ((1.17 ± 0.28) μg/L vs. (1.35 ± 0.23) μg/L, P < 0.001). Urine NGAL positively correlated with total serum bilirubin (r = 0.575, P < 0.001). Among all cases, neither serum creatinine nor daily urine output met neonatal acute kidney injury diagnostic criteria.

CONCLUSION

Severe hyperbilirubinemia may temporarily impair renal tubular reabsorption functions in full-term and near-term neonates, which is likely reversible. However, it has little effect on glomerular filtration function. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.