Lysosomal enzymes in preterm infants with bronchopulmonary dysplasia: a potential diagnostic marker

A comparison of KL-6 and Clara cell protein as markers for predicting bronchopulmonary dysplasia in preterm infants

OBJECTIVES

To evaluate the predictive characteristics of KL-6 and CC16 for bronchopulmonary dysplasia (BPD) in preterm infants, either independently or in combination.

STUDY DESIGN

This prospective cohort study was performed from 2011 to 2013 with preterm neonates of gestational age ≤32 weeks and birth weight ≤1500 g. Serum KL-6 and CC16 levels were determined 7 and 14 days after birth.

RESULTS

Seventy-three preterm infants were studied. BPD was identified in 24 of these infants. After adjusting for potential confounders, serum KL-6 concentrations were found to be elevated in BPD infants at both time points relative to non-BPD infants, while serum CC16 concentrations were lower at 14 days. At both 7 d and 14 d of life the predictive power of KL-6 levels exceeded that of CC16 (area under receiver operating characteristic curve: at 7 d, 0.91 cf. 0.73, P = 0.02; at 14 d, 0.95 cf. 0.85, P = 0.05). The combination of these markers enhanced the sensitivity further.

CONCLUSIONS

Serum KL-6 levels higher than 79.26 ng/mL at 14 days postpartum in preterm infants predict the occurrence of BPD. CC16 was less predictive than KL-6 at this time point, but KL-6 and CC16 together enhanced the prediction.

Early biomarkers as predictors for bronchopulmonary dysplasia in preterm infants: a systematic review

BACKGROUND

Bronchopulmonary dysplasia (BPD) is usually diagnosed in preterm infants at least 28 days after birth. Great interest lies in the potential to identify biomarkers that predict development of the disease and future neurodevelopmental outcomes. We have reviewed the existing literature on early biomarkers as predictors for BPD in preterm infants.

METHODS

Two reviewers independently searched the databases of PubMed, EMBASE, and Google Scholar for studies pertaining to biomarkers for BPD. Studies were assessed using Quality Assessment of Diagnostic Accuracy Studies criteria.

RESULTS

We identified 46 relevant articles that are summarized in the review. These studies assessed over 30 potential biomarkers. Sensitivity and specificity of biomarkers were reported or could be calculated for only 16 articles, and ranged from 0 to 100 %. Based on the nine highest quality studies, serum KL-6, CC16, neutrophil gelatinase-associated lipocalin, and end-tidal carbon monoxide (etCO) perform extremely well in predicting the early diagnosis of established BPD, highlighting these biomarkers as promising candidates for future research.

CONCLUSIONS

Published data from studies on serum biomarkers and etCO suggest that biomarkers may have great potential to predict the subsequent BPD and neurodevelopmental outcomes. These biomarkers need validation in larger studies, and the generalizability of biomarkers for predicting BPD, as well as the neurodevelopmental outcomes, needs to be further explored.

Age dependence of serum β-N-acetylhexosaminidase (NAG) activity

Serum N-acetyl-β-D-glucosaminidase (NAG; EC 3.2.1.30) is a hexosaminidase and may be a predictor of vascular injury, e.g., in infant respiratory distress syndrome, pneumonia, broncho-pulmonary dysplasia and necrotizing enterocolitis. To estimate the new diagnostic prospects we have modified our urinary NAG assay. In this sensitive colorimetric micro-assay, VRA-GlcNAc was used as a substrate. In the present study the age dependence of serum NAG activity was investigated in newborn babies, infants (1–24 months), children (2–18 years) and adults (19–80 years). Serum NAG activity was found to be age-dependent; it is higher in early childhood (11–59 U/l) but decreases to a constant value at the age of 1–2 years. After the age of 2 years it is similar to adults' NAG (10–30 U/l). In pediatrics age-matched reference ranges must be taken into consideration.