Preterm fetal growth restriction is associated with increased parathyroid hormone-related protein expression in the fetal membranes

OBJECTIVE: Parathyroid hormone-related protein has roles in normal fetal gr owth, placental calcium transport, and vascular tone regulation; these fact ors are compromised in growth-restricted fetuses. Our objective was to dete rmine whether intrauterine parathyroid hormone-related protein expression w as increased in association with fetal growth restriction. STUDY DESIGN: The expression of parathyroid hormone-related protein was exa mined in intrauterine tissues from women with idiopathic fetal growth restr iction with preterm (n = 8-10) and term (n = 8-10) gestations and from gest ation-matched control subjects. The abundance and immunoreactive content of parathyroid hormone-related protein messenger ribonucleic acid were determ ined by Northern blot and radioimmunoassay, respectively, in the placenta, amnion, and chorion-decidua. RESULTS: The expression of parathyroid hormone-related protein messenger ri bonucleic acid was increased in the amnion (placental and reflected) in ass ociation with preterm fetal growth restriction (P<.05). Both parathyroid ho rmone-related protein messenger ribonucleic acid and protein expression wer e increased in chorion-decidua in association with preterm fetal growth res triction (P<.05). In term gestations both parathyroid hormone-related prote in messenger ribonucleic acid and protein expression were greater in amnion over placenta than in reflected amnion (P <.05); these in turn were greate r than those in chorion-decidua (P<.05). No significant changes were detect ed in parathyroid hormone-related protein messenger ribonucleic acid or in protein expression in association with term fetal growth restriction. CONCLUSION: Either parathyroid hormone-related protein messenger ribonuclei c acid or protein expression, or both, was increased in the fetal membranes in association with fetal growth restriction in preterm but not term gesta tions, suggesting that parathyroid hormone-related protein may be involved In the pathogenesis of preterm fetal growth restriction.