Placental endothelial nitric oxide synthase expression and role of oxidative stress in susceptibility to preeclampsia in Pakistani women

BACKGROUND: Preeclampsia (PE): a hypertensive disorder of pregnancy characterized by de novo development of concurrent hypertension and proteinuria. The prevailing theory determined that PE starts from the placenta and ends in the maternal endothelium. Role of endothelial dysfunction in the onset of PE has been reported in different populations. Therefore, present study was designed to investigate the localization and expression of endothelial nitric oxide synthase (eNOS) and role of oxidative stress markers in preeclamptic Pakistani women. METHODS: A total of 400 blood samples (PE = 200, controls = 200) and 100 placental tissues (PE = 50, controls = 50) were recruited from pregnant women. Reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (POD) levels were analyzed through spectrophotometer. Immunohistochemistry and quantitative real‐time polymerase chain reaction (qRT‐PCR) were carried out to estimate the localization and expression of eNOS in the placentas of PE patients and healthy pregnant women. RESULTS: Significantly increased levels of POD (0.01), TBARS (0.04), and ROS (p ≤ .001) were determined in preeclamptic women while, nonsignificant change in SOD and CAT was observed in both groups. Reduced eNOS immunoreactivity (p ≤ .001) and mRNA abundance (p ≤ .001) was observed in preeclamptic group as compared to control group. CONCLUSION: Considering the results of current study, it is concluded that decreased eNOS expression and oxidative stress could play a role in the pathology of PE seen both in placenta and ultimately in maternal endothelium. However, large studies are necessary to validate these findings to prevent maternal and neonatal morbidity and mortality in Pakistani population.