Abstract
Purpose: In the light of contradictory results and paucity of information, this comprehensive study examines the activities and levels of key antioxidants and oxidants/pro-oxidants in preeclamptic patients.
Methods: Antioxidants including glutathione peroxidase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, catalase, reduced glutathione, selenium, zinc, copper and manganese, as well as marker oxidants/pro-oxidants including hydrogen peroxide, superoxide anions, malondialdehyde, protein carbonyls and oxidized glutathione were determined in plasma and placental tissues of nonpregnant, healthy pregnant and preeclamptic subjects.
Results: Data indicated that all plasma antioxidants underwent moderate but significant decreases (p< 0.05) in healthy pregnant women, and much more significant ones (p< 0.0001) in preeclamptic patients, when both were compared to non-pregnant subjects. Furthermore, whereas all plasma antioxidants underwent significant decreases (p< 0.001) in preeclamptic patients compared to healthy pregnant subjects, their placental activities and levels were very significantly decreased (p< 0.0001). However, copper plasma and placental levels were unchanged in all study groups. In contrast, there were increases similar in magnitude and significance of all plasma and placental oxidants/prooxidants compared among the three study groups leading to equally significant decreases in the reduced/oxidized glutathione ratios. In addition, gene transcripts of all antioxidant enzymes underwent marked downregulation (p< 0.0001) in placental tissue of preeclamptic patients compared to healthy pregnant subjects.
Conclusion: Data indicated a metabolic shift in favor of oxidative stress more pronounced in placental tissue of preeclamptic patients compared to healthy pregnant/non-pregnant subjects. We postulate that selenium, zinc and manganese supplements could be beneficial for alleviation of the noted oxidative stress in preeclamptic patients.