Difference in the expression of alpha 7 nicotinic receptors in the placenta in normal versus severe preeclampsia pregnancies

Objective: The prevalence of preeclampsia is low in smokers, suggesting a possible role of nicotinic receptor in the pathophysiology of the disease. Alpha 7 nicotinic acetylcholine receptor (α7 nAChR) was recently found in non-neuronal tissue with various mediating functions. Therefore, we investigated the difference in the placental expression of the α7 nAChR in normal versus severe preeclampsia placentas. Study design: Central portions of placenta were obtained from 9 severe preeclampsia women and 11 gestational-age-matched normal pregnant women delivered between the gestational ages of 33 and 40 weeks following elective or emergency cesarean section. RT-PCR, western blotting, and immunohistochemical staining were performed to evaluate the α7 nAChR expression difference. Results: In all the placentas, the α7 nAChR was expressed in endothelial cells, vascular smooth muscle cells, and stromal cells, but not in trophoblasts. The vascular staining was more intense in the severe preeclampsia placenta (p = 0.02). Although the gene expression did not differ between the two groups, protein expression was greater in 7 of 9 placenta samples from the severe preeclampsia group. Conclusion: Placental expression of α7 nAChR differs between normal and severe preeclampsia placentas, suggesting that it may be involved in the pathogenesis of preeclampsia.