Superoxide anion formation and glutathione levels in patients with preeclampsia

Endothelial dysfunction and preeclampsia: role of oxidative stress

Preeclampsia (PE) is an often fatal pathology characterized by hypertension and proteinuria at the 20th week of gestation that affects 5-10% of the pregnancies. The problem is particularly important in developing countries in where the incidence of hypertensive disorders of pregnancy is higher and maternal mortality rates are 20 times higher than those reported in developed countries. Risk factors for the development of PE include obesity, insulin resistance and hyperlipidemia that stimulate inflammatory cytokine release and oxidative stress leading to endothelial dysfunction (ED). However, how all these clinical manifestations concur to develop PE is still not very well understood. The related poor trophoblast invasion and uteroplacental artery remodeling described in PE, increases reactive oxygen species (ROS), hypoxia and ED. Here we aim to review current literature from research showing the interplay between oxidative stress, ED and PE to the outcomes of current clinical trials aiming to prevent PE with antioxidant supplementation.

Silibinin attenuates oxidative metabolism and cytokine production by monocytes from preeclamptic women

Silibinin is a polyphenolic plant flavonoid with anti-inflammatory properties. The present study investigated the effect of silibinin on oxidative metabolism and cytokine production - tumor necrosis factor-alpha (TNF-α), interleukin (IL)12, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, IL-10, and transforming growth factor beta (TGF-β1) - by peripheral blood monocytes (PBM) from preeclamptic pregnant women. It is a case-controlled study involving women with preeclampsia (PE, n = 30) compared with normotensive pregnant (NT, n = 30) and with non-pregnant (NP, n = 30) women. Monocytes were obtained and cultured with or without silibinin (5 μM or 50 μM) for 18 h. Superoxide anion (O2-) and hydrogen peroxide (H2O2) release were determined by specific assays, and cytokine levels were determined by immunoenzymatic assays (ELISA). Monocytes from preeclamptic women cultured without stimulus released higher levels of O22, H2O2 and TNF-α, and lower levels of IL-10 and TGF-β1 than did monocytes from NT and NP women. Treatment in vitro with silibinin significantly inhibited spontaneous O2- and H2O2 release and TNF-α production by monocytes from preeclamptic women. The main effect of silibinin was obtained at 50 μM concentration. Thus, silibinin exerts anti-oxidative and anti-inflammatory effects on monocytes from preeclamptic pregnant women by inhibiting the in vitro endogenous release of reactive oxygen species and TNF-α production.

Oxidative–Antioxidative System in Peripartum Acute Renal Failure and Preeclampsia‐Eclampsia

BACKGROUND

Preeclampsia-eclampsia and acute renal failure in peripartum women can be the cause of mortality and morbidity. There are many different reports about oxidative-antioxidative systems in preeclampsia-eclampsia. Until now, products of activated oxidative-antioxidative systems were not evaluated in peripartum women with acute renal failure. In this study, our aim was to evaluate the oxidative-antioxidative systems in peripartum women with acute renal failure and/or preeclampsia-eclampsia.

METHODS

The study groups consisted of 17 peripartum women (first week of delivery) with acute renal failure (G I), 11 preeclamptic (G II), 11 healthy pregnancy (> or = 30 weeks of pregnancy) (G III), and 11 healthy women (G IV) aged between 18-38 years. Superoxide dismutase (SOD), glutathione peroxidase (GSHPx) in erythrocytes, and plasma malondialdehyde (MDA) levels were measured in all groups. SOD, GSHPx, and MDA levels were also measured at the onset of acute renal failure (G IA), regression of renal dysfunction (G IB) and recovery of renal functions (G IC).

RESULTS

MDA levels were 11.95+/-4.25, 9.22+/-3.62, 5.10+/-3.65, 3.40+/-1.27, 4.91+/-2.06, 4.24+/-1.67 mmol/mL in G IA, G IB, G IC, G II, G III, and G IV, respectively. SOD activity in erythrocyte were 3269.23+/-1437.83, 2641.35+/-1411.13, 2056.35+/-1143.11, 924+/-160.04, 1057.91+/-257.03, 861.63+/-243.28 Ug/Hb in G IA, G IB, G IC, G II, G III, and G IV, respectively. GSHPx activity in erythrocyte was 70.17+/-23.52, 58.27+/-23.75, 45.44+/-17.60, 24.48+/-6.77, 26.28+/-7.27, 32.95+/-8.24 Ug/Hb in G IA, G IB, G IC, G II, G III, and G IV, respectively. MDA levels and activities of SOD, GSHPx in erythrocytes were highest in GIA The values of MDA, SOD, and GSH-Px in G IA, G IB, and G IC were significantly different from each other and decreased while regaining of renal functions. Preeclampsia-eclampsia or normal pregnancy did not cause elevation of plasma MDA levels and GSHPx, SOD in erythrocyte.

CONCLUSION

Although SOD and GSHPx in erythrocytes and plasma MDA level were found to be similar in healthy women, pregnant women, and preeclamptic women; SOD, GSHPx, and MDA increased at the beginning and decreased during recovery of renal functions in peripartum women with acute renal failure.

The NADPH- and iron-dependent lipid peroxidation in human placental microsomes

In pregnant females, placenta is the most important source of lipid hydroperoxides and other reactive oxygen species (ROS). The increased production of lipid peroxides is often linked to preeclampsia. In our study, we revealed that NADPH- and iron-dependent lipid peroxidation in human placental microsomes (HPM) occurred. In the presence of Fe2+ ion, HPM produced small amounts of thiobarbituric acid-reactive substances (TBARS) - a final product of lipid peroxidation. NADPH caused a strong increase of iron stimulated TBARS formation. TBARS formation was inhibited by superoxide dismutase, butylated hydroxytoluene and alpha-tocopherol but not by mannitol or catalase. TBARS and superoxide radical production was inhibited in similar manner by cytochrome P450 inhibitors. The results obtained led us to the following conclusions: (1) microsomal lipid peroxidation next to mitochondrial lipid peroxidation may by an important source of lipid hydroperoxides in blood during pregnancy and (2) superoxide radical released by microsomal cytochrome P450 is an important factor in NADPH- and iron-dependent lipid peroxidation in HPM.

Vitamin E and C in preeclampsia

Vascular endothelial damage has been implicated in the pathophysiology of preeclampsia. Lipid peroxidation may be involved in the process and essential nutrients that can scavenge free radicals, such as vitamin E and C, operate in concert. Antioxidant vitamins E and C were estimated in 30 preeclamptic and 30 normotensive pregnant women. Significantly lowered levels of vitamins E and C were observed in preeclamptic women as compared to controls (P<0.001 and P<0.05 respectively). In patients with preeclampsia antioxidant nutrients may be utilized to a greater extent to counteract free radical-mediated cell disturbances, resulting in a reduction in serum antioxidant levels.