The relationship between reticulated platelets, intestinal alkaline phosphatase, and necrotizing enterocolitis

Abstract

Background Necrotizing enterocolitis (NEC) affects up to 10% of extremely-low-birthweight infants, with a 30% mortality rate. Currently, no biomarker reliably facilitates early diagnosis/prevention. Since thrombocytopenia and bowel ischemia are consistent findings in advanced NEC, we prospectively investigated the impact of two potential biomarkers: reticulated platelets (RP) and intestinal alkaline phosphatase (iAP). Methods Infants born ≤32 weeks and/or ≤1500g were prospectively enrolled from 2009–2012. Starting within 72 hours of birth, 5 weekly whole blood specimens were collected to measure RP and serum iAP. Additional specimens were obtained at NEC onset (Bell stage II or III) and 24 hours later. Dichotomous cut-points for both biomarkers sought to maximize sensitivity. The Mann-Whitney U test highlighted differences in median biomarker levels between NEC and non-NEC infants. Chi-square or Fisher’s exact test highlighted categorical differences. The Kaplan-Meier method and Logrank test estimated the probability of developing NEC. The Cox proportional hazards model estimated hazard ratios. Results Of 177 infants, 8.5% developed NEC. Of these, 40% required surgery, 20% expired before discharge, 93% had “low” RP (≤2.3%), and 60% had high iAP (>0 U/L). Infants with “low” RP were significantly more likely to develop NEC [HR=11.0 (1.4–83); p=0.02], while those with “high” iAP showed a similar trend [HR=5.2 (0.7–42); p=0.12]. Median iAP levels were significantly higher at week 4 (p=0.02), preceding the average time to NEC onset by one week (35.7 ± 17.3 days). Conclusion Decreased RP serves as a sensitive marker for NEC onset, thereby enabling early preventative strategies. iAP overexpression may signal NEC development.

Intestinal alkaline phosphatase to treat necrotizing enterocolitis

“…It has been shown that higher serum levels of IAP may be predictive of NEC development in neonates [22]. This may seem in contradiction to our results showing lower IAP, measured in the intestinal tissue, in those with histologic injury consistent with NEC.…”

Association of Intestinal Alkaline Phosphatase With Necrotizing Enterocolitis Among Premature Infants

“…Serum is not an ideal sampling source, as 4 different alkaline phosphatases are present, and their relative levels in serum are known to change during gestation 59 (eFigure 1 and eFigure 2 in the Supplement). Although prior conclusions drawn 58 support our findings, sole use of denaturing protein gels cannot provide equivalent evidence that IAP was identified nor is it capable of quantifying the amount of alkaline phosphatase in general.…”

“…Both approaches are necessary to distinguish disease pathways and differences between individuals. Serological tests 58 of alkaline phosphatase as an NEC biomarker reported that the amount of IAP in blood was increased in infants with NEC compared with controls, suggesting that IAP may play a role in NEC pathogenesis. Serum is not an ideal sampling source, as 4 different alkaline phosphatases are present, and their relative levels in serum are known to change during gestation 59 (eFigure 1 and eFigure 2 in the Supplement).…”

A New Two-Photon Ratiometric Fluorescent Probe for Detecting Alkaline Phosphatase in Living Cells

“…As an important diagnostic enzyme, ALP has long been serving as a biomarker in enzyme immunoassays and molecular biology [3], as well as a diagnostic indicator of many human diseases [4]. The normal level of ALP activity in human serum is in a range of 40-150 U/L [5] and the abnormal level of serum ALP are commonly correlated to several diseases such as bone disease, liver dysfunction, breast and prostatic cancer, diabetes and so on [6,7]. Thus, it is highly desirable to develop a sensitive, selective approach to detect ALP in diagnostic and clinical assays.…”