Study of serum transferrin, homocysteine, and nitric oxide in preeclampsia and its relation to serum lipid peroxidation

ABSTRACT

To investigate serum lipid peroxides, and some of the antioxidants [glutathione peroxidase activity and serum transferrin] as well as to measure serum homocysteine and total nitrites as an index of serum nitric oxide in preeclampsia and normal pregnancy. Twenty nulliparous subjects who had preeclampsia [PE] were recruited in this study. Twenty women who had uncomplicated pregnancies and age matched, were included as control group. These control women were normotensive, throughout gestation and without proteinuria. Patients with cigarette use, chronic hypertension, renal or metabolic disease or previous history of metabolic disorders were excluded. Fasting serum samples were obtained before delivery [AP] and 24 hours postpartum [PP]. The separated serum was investigated for serum iron and total transferrin concentration. Percent saturation of iron-binding capacity is measured as [serum iron/total iron binding capacity X 100]. Determination of serum lipid peroxides and homocysteine were done. The activity of glutathione peroxidase in red cell hemolysate was also determined. Total nitrites was measured as an index of nitric oxide concentration, in the maternal circulation of normal pregnant women and women with preeclampsia. Serum lipid peroxides were elevated in PB women relative to normal pregnant women controls before delivery [p<005] and decreased after delivery in women with preeclampsia compared with antepartum level [p<005]. There was no significant difference with normal pregnant postpartum level. Serum iron was significantly increased in PE pregnant women compared with normal pregnant women [p<0.05] and it decreased significantly after delivery compared with predelivery level in PE women [p<005]. Serum transferrin level was significantly reduced in pregnant women with PE as compared with normal pregnant women [p<0.05]. After delivery, serum transferrin concentration was significantly reduced in PB women [p<0.001] and normal controls [p<0.001] as compared to the corresponding antepartum levels and in PE women compared to PP normal pregnant women [p<0.05] Transferrin percent saturation was significantly elevated in pregnant women with PB as compared with normal pregnant controls. [p<0.05]. After delivery, transferrin percent saturation was significantly decreased in PP PB women compared with PE AP level [p<0.05]. In controls, there was no significant difference in PP level of transferrin saturation as compared with normal AP level or PP PB level. Glutathione peroxidase enzyme activity was significantly reduced in PE pregnant females compared with normal pregnant controls [p<0.05]. Homocysteine level was found to be significantly elevated in PB females compared with normal pregnant controls. [p<0.001] After delivery, serum homocysteine level was significantly reduced in PE females compared with PE AP level [p<0.001] but still was significantly higher than normal postpartum controls [p<0.001]. Serum total nitrites was significantly increased in PE pregnant females as compared to normal pregnant controls [P<0.05]. After labour, it was significantly reduced compared to PB Ap level [p<0.05] A significant positive correlation as observed between percent transferrin saturation and serum lipid peroxides in normal pregnancy before and after delivery [[r= 0.42, p<0.01], [r= 0.37, p<0.01] respectively]. In preeclampsia, the same parameters exhibited a highly significant positive correlation before and after delivery [[r=0.62, p<0.001], [r=0.45, p<0.001]]. Hyperhomocysteinemia and the increase in serum iron as well as the increased serum transferrin saturation in preeclampsia, are factors that increase oxidative stress coupled to an impaired ability to detoxify peroxides as evidenced by reduced glutathione peroxidase activity. The increased oxidation stress might interfere with the bioavailability of nitric oxide in preeclampsia