Procollagen Type I amino-terminal propeptide : pediatric reference data and relationship with procollagen type I carboxyl-terminal propeptide

Abstract

Type I collagen is the predominant collagen in bone and soft tissue. The rate of synthesis of type I collagen can be assessed by measuring plasma concentrations of the C-terminal (PICP) and N-terminal (PINP) propeptides released during extracellular processing of its procollagen precursor . However, the propeptides have different clearance routes, PICP being cleared by mannose receptors and PINP by scavenger receptors in liver endothelial cells. Clearance of PICP may be modulated by the hormonal milieu, whereas scavenger receptors apparently are not influenced by hormones. Within-individual biological variability is similar for PICP and PINP, but PINP displays greater dynamic changes than PICP in response to disease and interventions. PINP has been shown to be a useful marker of bone formation in adults.