Peroxisome proliferator-activated receptor-gamma in normal human pregnancy and miscarriage

Peroxisome proliferator-activated receptors (PPAR) belong to the superfamily of nuclear hormone receptors. Recent investigations emphasize a possible involvement of PPAR in obstetric and gynaecologic disorders like polycystic ovarian syndrome, endometriosis and preeclampsia. The aim of this study was to determine the frequency and distribution of peroxisome proliferator-activated receptor-gamma (PPARgamma) in normal human pregnancy and miscarriage. Placental tissue was obtained from normal human pregnancy and miscarriage during the first trimester of pregnancy. PPARgamma localisation was investigated by immunohistochemical methods. Immediate immunoreactivity of PPARgamma was observed in villous and extravillous trophoblast nuclei in normal first trimester pregnancy. A significantly enhanced labelling of PPARgamma was identified in extravillous trophoblast of miscarriage patients. This enhanced immunopositivity was also found in nuclei of villous trophoblast cells of miscarriage patients but without statistical significance. Because trophoblast invasion is negatively correlated to PPARgamma stimulation and blocking of PPARgamma leads to increased trophoblast invasion, our findings may suggest that enhanced expression of PPARgamma in abortive extravillous trophoblasts may be one factor linked to miscarriage.