01-02-2007 | Original Article
Leptin and bone turnover in monochorionic twins complicated by twin–twin transfusion syndrome
Published in: Osteoporosis International | Issue 2/2007
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Introduction
To test the hypothesis that the bone metabolism of a growth-restricted foetus is regulated by genetic, placental and/or foetal factors through leptin, we investigated the foetal bone turnover in monochorionic pregnancies complicated with or without twin–twin transfusion syndrome (TTTS).
Methods
Maternal and cord bloods were collected from gestational-age-matched monochorionic twins with (n = 15) and without (n = 15) TTTS. The samples were assayed for leptin, cross-linked carboxyl terminal telo-peptide (ICTP, a marker of bone resorption) and pro-peptide (PICP, a marker of bone formation) of type I collagen by radioimmunoassay (RIA).
Results
In the growth-restricted donor twin, the plasma concentration of leptin (P < 0.001), PICP (P < 0.001) was lower, while that of ICTP (P < 0.001) was higher than the recipient twin of the TTTS group. In contrast, leptin, PICP and ICTP were comparable in non-TTTS twins. In the recipient twin of TTTS and non-TTTS twins, leptin was positively associated with PICP (r = 0.73; n = 45, P < 0.001) and negatively with ICTP (r = −0.68; n = 45; P < 0.001). No such association was found between leptin and bone marker in the growth-restricted donor twin of the TTTS group.
Conclusion
Our data suggest that, in AGA twins, leptin maintains bone metabolism by inhibiting resorption and enhancing bone formation. In contrast, growth-restricted donor twins have high bone turnover and this does not seem to be due to leptin deficiency.