THE NITRIC-OXIDE PATHWAY IN PREECLAMPSIA - PATHOPHYSIOLOGICAL IMPLICATIONS

Pre-eclampsia, one of the most significant health problems in human pr egnancy, complicates similar to 6-8% of all gestations and is the lead ing cause of fetal growth retardation, infant morbidity and mortality, premature birth and maternal death. Recent research implicates free r adicals in the pathophysiology of pre-eclampsia, This review covers th e biochemistry of nitric oxide (NO) and possible interactions with oth er free radicals. Studies in the rat show that pregnancy is associated with enhanced production and responsiveness to NO in both reproductiv e tissues and blood vessels. Rats infused with N-G-nitro-L-arginine me thyl ester (L-NAME, a NO synthase inhibitor) have been used as art ani mal model of pre-eclampsia, and the effects of steroid hormones on blo od pressure in this model have been tested. Results suggest that pre-e clampsia may be a state of NO deficiency. However, in humans there see m to be contradictions regarding the involvement of NO in maternal ada ptation to pregnancy. It is suggested that NO may be one of several sy stems that act in concert to maintain a symbiotic relationship between mother and fetus, However, the input of each system may be geneticall y determined.