Endothelial dysfunction in the human umbilical artery due to preeclampsia can be prevented by sildenafil.

Objectives: We aimed to determine the effects of sildenafil in human umbilical artery preparation taken from preeclamptic or normal pregnant women, also to investigate underlying mechanisms in these effects.

Study Design: Eighteen pregnant women with preeclampsia and 18 healthy pregnant women were involved. Relaxation responses of sildenafil in presence and absence of nitric oxide (NO) synthase inhibitor, N-[omega]-nitro-L-arginine methyl ester (L-NAME), and soluble guanylyl cyclase inhibitor, 1H-[1,2,4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ), were compared between the preeclampsia group and control group.

Results: Sildenafil-induced relaxation responses were significantly attenuated in the presence of preeclampsia, L-NAME or ODQ, but not totally abolished. Interestingly, except with ODQ incubation, in all set of experiments maximal relaxation response was achieved by sildenafil.

Conclusion: These data indicate that sildenafil might effect vascular responsiveness of human umbilical artery through the involvement of NO/cyclic guanosine monophosphate (cGMP)-dependent and -independent pathways. Further investigations are needed to clarify the exact mechanisms.