Plasma concentrations of the carboxyterminal propeptide of type I procollagen (PICP) in preterm neonates from birth to term.

Carboxyterminal propeptide of type I procollagen (PICP), a marker of bone formation, has not yet been studied in preterm infants. In this study, PICP concentrations were measured longitudinally for 12 wk after birth using the ELISA technique in 43 preterm infants with a gestational age (GA) ranging from 24-29 wk and in 35 preterm infants with a GA ranging from 30-34 wk. PICP values in these preterm infants were higher than in children and adults. In cord plasma of preterm infants there was a significant gender difference, with higher PICP concentrations in male infants. A characteristic longitudinal pattern with an initial decrease during the first 3 postnatal days followed by a rapid increase from d 7 to d 28 was seen in both groups. Regarding the individual gestational ages, all preterm infants attained maximum PICP concentrations around 36 wk postmenstrual age. Multiple regression analysis revealed cord plasma PICP concentrations were significantly associated with GA, birth weight, sex, and IGF-I. A significant correlation between PICP concentrations and GA was seen at wk 1-4 and between PICP concentrations and protein intake at wk 1. Body weight and energy intake were shown to exert a significant effect on the PICP concentrations at 2 wk. The collected data in preterm infants may serve further studies evaluating PICP as a marker for bone formation and growth in very low birth weight premature infants.