New use of alkaline phosphatase in neonatology

Abstract

Background. Alkaline phosphatase is an enzyme that catalyzes the hydrolysis of esters in an alkaline environment. Four isoenzymes have been identified in the human body: placental alkaline phosphatase (PLALP isoenzyme), intestinal alkaline phosphatase (IAP), hepatic/bone/renal alkaline phosphatase (L/B/K ALP) and germ cell alkaline phosphatase (GCALP). The uses of ALP in neonatology have been intensively studied, and associations have been demonstrated between elevated alkaline phosphatase levels and hypocalcemia and hypophosphatemia in premature infants, the onset of early osteopenia and the occurrence of necrotizing enterocolitis. Objective. The current study aimed to demonstrate the correlation between elevated alkaline phosphatase levels in blood from the umbilical cord and elevated transcutaneous bilirubin levels that indicated phototherapy. Material and methods. The study included 250 term newborns within 01-06.2018 and 31 had indication for phototherapy, and 219 without indication for phototherapy, in a tertiary maternity hospital in Bucharest, Romania. Alkaline phosphatase was determined in the umbilical cord serum. Results. The values of the alkaline phosphatase were from 145 to 417 U/l for the newborns without phototherapy and the treated group was beetween 320 and 602 U/l. The values of the alkaline phosphatase were not influenced by the birth weight, Apgar score, and gender. Conclusions. Alkaline phosphatase may represent a predictive marker for the need for phototherapy in term neonates, but further extended studies are required on larger groups of patients.

Keywords

• alkaline phosphatase
• transcutaneous bilirubin
• phototherapy
• term newborn