The relationship between leptin concentration and bone metabolism in the human fetus

This study investigates the relationship between leptin and fetal bone meta bolism by measuring fetal blood levels of leptin, carboxyterminal pro-pepti de of type I pro-collagen (PICP; a marker of bone formation) and cross-link ed carboxy-terminal telopeptide of type I collagen (ICTP; a marker of bone resorption). The median gestational age at the time of sampling was 23 week s (range, 18-35). There was a positive correlation between leptin concentra tion and gestational age (r = 0.543, P < 0.001) and a negative correlation between both PICP and ICTP and gestational age (r = -0.592 and r = -0.550, respectively, and P < 0.001 for both). Also, there was a negative correlati on between the concentrations of leptin and both PICP (r = -0.260, P = 0.02 2) and ICTP (r = -0.622, P < 0.001). Using multiple regression analysis, fe tal leptin concentration was positively correlated to the gestational age ( r = 0.240, P = 0.042) and negatively correlated to ICTP (r = -0.420, P = 0. 001). The increase in leptin concentration with gestational age is consiste nt with adipose tissue development and the subsequent accumulation of fat m ass. The negative correlation between fetal leptin and ICTP suggests that l eptin may decrease bone resorption with the overall effect of increasing bo ne mass. Therefore, leptin may play a role in fetal bone metabolism as part of its effect on fetal growth and development.