PLACENTAL EXPRESSION OF ENDOTHELIAL CONSTITUTIVE NITRIC-OXIDE SYNTHASE MESSENGER-RNA IN PREGNANCY COMPLICATED BY PREECLAMPSIA

Background. The role of nitric oxide (NO) in normal pregnancy and preg nancy complicated with preeclampsia (PE) and/or intrauterine growth re striction (IUGR) still remains questionable. The placenta lacks autono mic innervation, therefore blood flow must be regulated by humoral and endothelium derived factors. NO is a potent vasodilator released by e ndothelial cells. It is synthesized by the catalytic action of the end othelial constitutive nitric oxide synthase (ecNOS). Moreover, the syn thesis of NO in normal human placental vasculature has already been es tablished and impairment of the uteroplacental blood how in pregnancie s complicated by PE and/or IUGR has been demonstrated. Design and meth ods. The aim of the present study was to compare the expression of ecN OS mRNA in placenta from women with complicated and normal pregnancies . Placenta was collected from women with PE (n=13) or small for gestat ional age (SGA) (n=8), both PE and SGA (n=7) and normal pregnancies (n =41). Total nucleic acids were prepared and a solution hybridization t echnique was used for mRNA analysis. Result. The mRNA expression of ec NOS was significantly higher (p<0.05) in all groups of complicated pre gnancies compared to normal pregnancies. Conclusion. Our findings indi cate that the increased placental expression of ecNOS mRNA might refle ct a compensatory mechanism in the disturbed uterine circulation seen in PE and/or SGA.