Expression of the Na+-H+ exchanger ISOFORM-1 and cyclooxygenases in human placentas: Their implications in preeclampsia

The sodium hydrogen exchanger isoform, NHE-1 plays an important role in ele ctrolyte and water homeostasis. These functions are compromised in pregnanc ies complicated with preeclampsia. At present it is not known whether NHE-1 expression is altered during preeclampsia. In the present study the placen tal level of NHE-1 protein was measured using immunoblotting. Since prostag landins regulate the secretory and absorptive functions, the levels of pros taglandin E-2 as well as the expression of cyclooxygenase-1 and -2 were als o estimated. The amount of NHE-1 protein and cyclooxygenase-2 was reduced i n preeclamptic placentas, whereas the level of cyclooxygenase-l remained un altered. In contrast, prostaglandin E-2 concentration was higher in preecla mpsia. Suppression of NHE-1 might render the placenta with impaired uptake of water and electrolytes and therefore may be involved in the pathogenesis of preeclampsia. While prostaglandin E-2 may play a role in preeclampsia, these findings discount the induction of cyclooxygenase-genes for this incr ease.