Changes in Free NO Levels in Umbilical Cord Blood of Women in Labor at Physiological Pregnancy and Pregnancy Complicated with Pre-eclampsia

Tinatin Khetsuriani, Paata Makharashvili, Irakli Mamamtavrishvili, Eka Khurtsidze, Nikoloz Kintraia, Tamar Sanikidze

Chachava Scientific Research Institute of Perinatal Medicine, Obstetrics and Gynecology, Tbilisi State Medical University, Georgia

So far the etiology and pathogenesis of one of the frequent and dangerous complication of pregnancy, pre-eclampsia has been less studied. There are lots of evidences suggesting that various complications of pre-eclampsia, including vascular reactivity changes, vasospasm and multiorganic pathologies, occur due to the development of pathological changes in maternal vascular endothelium. There has been suggested that nitric oxide deficiency plays significant role in the development of structural and functional changes of vascular endothelium in maternal organism. Numerous evidences also prove a significant role of nitric oxide in regulation of uterine contractility during pregnancy and childbirth. Proceeding from aforesaid, our research aimed to study changes in blood NO levels of umbilical cord of women at childbirth during physiological pregnancy and pregnancy complicated with pre-eclampsia. As it proceeds from the results obtained in our study, in cases of pregnancy complicated with pre-eclampsia intensity of EPR signal of HbNO complexes in umbilical cord blood of women at childbirth is much higher as compared with those of women with physiological pregnancy. This fact first of all, indicates an activation of inducible NOS (iNOs) and enhanced generation of nitric oxide under the conditions of oxidative stress, characteristic of pre-eclampsia. Excessive NO easily nitrolyses deoxyhemoglobin with formation of nitrosohemoglobin (HbNO). This mechanism provides a decrease in free NO blood levels. Under the conditions of oxidative stress free nitric oxide may be also converted to citotoxic peroxinitrite, which displays high constrictive activity. Significant lowering of free NO body levels during pregnancy complicated with pre-eclampsia contributes to the enhancement of vascular resistance and aggravation of endothelium dysfunction, characteristic of this syndrome, and may induce activation of uterine contractility and pathological childbirth.

Keywords:  pregnancy, Umbilical Cord Blood, nitric oxide, pre-eclampsia