Prostacyclin, thromboxane and antioxidant levels in pregnancy-induced hypertension

Antioxidant Activity and Oxidative Stress Status in Maternal Serum of β-thalassemic Mothers Carrying β-thalassemic Major and Normal Fetuses

Objectiveβ-thalassemia is a genetic disorder characterized by reduction or absence of β-globin chain with mutations in both copies (β-thalassemia major) or in one copy (β-thalassemia minor). Pregnancies in β- thalassemic carrier women are considered symptom free but have risk of inheriting β-thalassemic fetuses. Current study was designed to compare oxidative stress and antioxidants status in maternal serum from β-thalassemic minor mothers having β-thalassemic major and normal fetuses. Method: We investigated paraoxonase (PON1) and arylesterase (ARE) activities along with malondialdehyde (MDA) and reactive oxygen species (ROS) in maternal serum of β-thalassemic carrier women. Results: PON1 and ARE activities were found to be significantly decreased, whereas the concentration of MDA and ROS were significantly increased in β-thalassemic minor mothers with β-thalassemic major fetuses. Conclusion: The study concludes that redox imbalance in β-thalassemic trait mothers carrying thalassemic fetuses is higher than in mothers carrying normal fetuses.

Selenium status in U.K. pregnant women and its relationship with hypertensive conditions of pregnancy

Dietary intake/status of the trace mineral Se may affect the risk of developing hypertensive conditions of pregnancy, i.e. pre-eclampsia and pregnancy-induced hypertension (PE/PIH). In the present study, we evaluated Se status in U.K. pregnant women to establish whether pre-pregnant Se status or Se supplementation affected the risk of developing PE/PIH. The samples originated from the SPRINT (Selenium in PRegnancy INTervention) study that randomised 230 U.K. primiparous women to treatment with Se (60 μg/d) or placebo from 12 weeks of gestation. Whole-blood Se concentration was measured at 12 and 35 weeks, toenail Se concentration at 16 weeks, plasma selenoprotein P (SEPP1) concentration at 35 weeks and plasma glutathione peroxidase (GPx3) activity at 12, 20 and 35 weeks. Demographic data were collected at baseline. Participants completed a FFQ. U.K. pregnant women had whole-blood Se concentration lower than the mid-range of other populations, toenail Se concentration considerably lower than U.S. women, GPx3 activity considerably lower than U.S. and Australian pregnant women, and low baseline SEPP1 concentration (median 3.00, range 0.90-5.80 mg/l). Maternal age, education and social class were positively associated with Se status. After adjustment, whole-blood Se concentration was higher in women consuming Brazil nuts (P= 0.040) and in those consuming more than two seafood portions per week (P= 0.054). A stepwise logistic regression model revealed that among the Se-related risk factors, only toenail Se (OR 0.38, 95% CI 0.17, 0.87, P= 0.021) significantly affected the OR for PE/PIH. On excluding non-compliers with Se treatment, Se supplementation also significantly reduced the OR for PE/PIH (OR 0.30, 95% CI 0.09, 1.00, P= 0.049). In conclusion, U.K. women have low Se status that increases their risk of developing PE/PIH. Therefore, U.K. women of childbearing age need to improve their Se status.

Antioxidant status and serum levels of selectins in pre-eclampsia

A cross-sectional study was conducted in a university hospital, enrolling 40 patients with pre-eclampsia (case group) and 40 healthy normotensive pregnant women (control group). Plasma activity of antioxidants and some adhesion molecules involved in oxidative stress were measured and compared between the two groups, according to the patients' age. In patients over the age of 30 years, serum levels of L-selectin and E-selectin were lower in pre-eclamptic patients (p < 0.05); antioxidants, catalase and superoxide dismutase did not significantly differ between the two groups, while glutathione peroxidase was significantly higher in the normotensive group (p < 0.05). In patients under the age of 30 years, E-selectin was significantly higher in the pre-eclampsia group (p < 0.05), while P-selectin, catalase and superoxide dismutase were not significantly different between the two groups (p > 0.05). Total antioxidative activity was similar between pre-eclamptic and normotensive patients (p > 0.05). This study revealed no relationship between total antioxidant activity and pre-eclampsia.

The role of homocysteine, asymmetric dimethylarginine and nitric oxide in pre-eclampsia

Nitric oxide (NO) contributes to vasodilatation that is observed during normal pregnancy. Hyperhomocysteinaemia (HHcy) is a vascular risk factor associated with placental microvascular diseases and pre-eclampsia. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide synthase (NOS) has been linked to endothelial dysfunction. Maternal ADMA has been reported to be higher in women with pre-eclampsia and HHcy leads to accumulation of ADMA. The aim of this presented study is to evaluate the alterations of plasma homocysteine, ADMA and NO levels in mild pre-eclampsia. A total of 40 pre-eclamptic women and 40 healthy controls were included into the study. Mean systolic and diastolic blood pressure, mean serum homocysteine and ADMA levels were significantly higher and NO level was lower in patients. Serum homocysteine, ADMA and NO levels found to be correlated among them and with blood pressure. In conclusion, we found that homocysteine and ADMA levels were increased and NO levels decreased in pre-eclampsia.

COX-2 Inhibition by Use of Rofecoxib or High Dose Aspirin Enhances ADP-Induced Platelet Aggregation in Fresh Blood

Aim:

Increased cardiovascular risk after use of selective or nonselective cyclooxygenase-2 (COX-2)-inhibitors might partly be caused by enhanced platelet aggregability. However, an effect of COX-2 inhibition on platelets has so far not been observed in humans.

Methods:

We tested in healthy volunteers the effect of COX-2-inhibition nearly in-vivo, i.e. immediately after and even during blood sampling.

Results:

Measurement within 2 minutes after venipuncture, but not 60 minutes later, showed that 50 mg of rofecoxib (n=12) or 500 (n=8) or 1000 (n=8) mg of aspirin increased ADP-induced platelet aggregation in a whole-blood aggregometer to, respectively, 152, 176 and 204 % of basal level (p<0.01). No significant differences in aggregability were observed after ingestion of 80 mg of aspirin (n=16), or placebo (n=8). Plasma 6-keto-PGF1α was decreased to 74 % after rofecoxib and to 76 and 70 % after 500 and 1000 mg of aspirin but did not change after low dose aspirin. Continuous photometrical measurement of aggregation in blood flowing from a cannulated vein revealed that high dose aspirin did not elicit aggregation by itself, but increased ADP-induced aggregation in proportion to the decrease in prostacyclin formation (r=0.68, p = 0.004). Since in these experiments thromboxane production was virtually absent, the enhanced aggregation after partial COX-2 inhibition was not caused by unopposed thromboxane formation.

Conclusions:

We conclude that both selective and nonselective COX-2 inhibition enhances ADP-induced platelet aggregation in humans. This effect can only be detected during or immediately after venipuncture, possibly because of the short half-life of prostacyclin.

Total Antioxidant Capacity and Antioxidant Enzymes in Serum, Saliva, and Gingival Crevicular Fluid of Preeclamptic Women With and Without Periodontal Disease

BACKGROUND

The aim of this study was to investigate the total antioxidant capacity, superoxide dismutase and glutathione peroxidase activities, and malondialdehyde levels in serum, saliva, and gingival crevicular fluid (GCF) in preeclamptic and normotensive pregnant women with and without periodontal disease.

METHODS

Forty pregnant women, consisting of 10 preeclamptic subjects with periodontal disease, 10 preeclamptic periodontally healthy subjects, 10 normotensive subjects with periodontal disease, and 10 normotensive periodontally healthy subjects, were included in this study. After clinical measurement and samplings, total antioxidant capacity, superoxide dismutase, glutathione peroxidase activities, and malondialdehyde levels in serum, saliva, and GCF of preeclamptic and normotensive pregnant women were determined, and the data were tested by non-parametric tests. Total antioxidant capacity of the clinical samples was measured using a novel automated colorimetric measurement method. Superoxide dismutase and glutathione peroxidase activities and malondialdehyde levels were determined spectrophotometrically.

RESULTS

Superoxide dismutase and glutathione peroxidase activities in GCF and serum and total antioxidant capacity in saliva, GCF, and serum were the lowest in preeclamptic women with periodontal disease. However, serum and GCF levels of malondialdehyde were the highest in this group of pregnant women.

CONCLUSIONS

Systemic and local antioxidant and total antioxidant capacities are affected by periodontal disease in addition to the impact of preeclamptic status. Similar comments may be made for the increases in systemic and local malondialdehyde levels.

Role of anion gap and different electrolytes in hypertension during pregnancy (preeclampsia)

The present study was designed to determine the changes in serum sodium, anion gap, different antioxidants and free radicals in preeclamptic patients and control subjects. Serum sodium, chloride, bicarbonate, calcium, potassium and magnesium were estimated and anion gap was determined in 100 proteinuric hypertensive and 100 normotensive pregnant women. Mean serum sodium, chloride and bicarbonate level (133.26 +/- 13.1, 104.97 +/- 11.37, and 22.01 +/- 4.66 mEq/l, respectively) were significantly higher in proteinuric hypertensive women as compared to controls (125.85 +/- 10.4, 101.90 +/- 6.3, 19.34 +/- 3.21 mEq/l, respectively) whereas anion gap level (6.28 +/- 16.147) was nonsignificantly higher in proteinuric hypertensive as compared to normotensive (4.61 +/- 11.84). Total serum sodium concentration increases in preeclamptic subjects, the exact distribution of serum sodium in various compartments of the body are not clear and correlation of serum sodium and anion gap with proteinuria is also not known. The levels of different antioxidants were decreased in preeclamptic patients as compared to the controls while the level of free radicals elevated in preeclamptic subjects as compared to controls. In our study, anion gap level was found to be rather non-significantly higher in proteinuric hypertensive women as compared to normotensive women.

Lipid peroxidation, antioxidant defense, status of trace metals and leptin levels in preeclampsia

OBJECTIVE

To investigate the changes in enzyme activities of erythrocyte superoxide dismutase (SOD), catalase, and placental glutathione peroxidase (GSH-Px), and analyze the levels of serum malondialdehyde (MDA), copper (Cu), zinc (Zn), selenium (Se), leptin and placental MDA and glutathione (GSH).

STUDY DESIGN

Cross-sectional prospective study consisting of 32 preeclamptic (PE) pregnant, 25 non-pregnant (NP) women, 28 healthy pregnant (HP) women. Levels of lipid peroxides in serum and placenta, and activities of SOD, catalase in erythrocyte and placental GSH level, placental GSH-Px activity were measured by spectrophotometric methods. Serum levels of Cu, Zn, Se measured by atomic absorption spectrophotometry. Serum levels of leptin was measured by enzyme immunoassay by using the Cayman chemical kit. One-way analysis of variance and post hoc Tukey-HSD test and Pearson correlation test were used for the statistical analyses.

RESULTS

Serum levels of MDA, Cu, Leptin were markedly higher (P < 0.001); and serum level of Se was markedly lower (P < 0.001) in PE women compared with HP women and NP women. Also, placental MDA level was higher (P < 0.001) and placental GSH-Px activity was lower in PE women compared with HP women. In preeclamptic women erythrocyte catalase activity was markedly increased (P < 0.001), while erythrocyte SOD activity was markedly decreased (P < 0.001) compared to HP women and NP women. Placental GSH level was decreased compared to HP women (P < 0.001). Serum level of Zn was markedly decreased compared to NP women (P < 0.001) but no significant difference was observed in PE pregnant when compared with HP women (P > 0.05). Placental MDA level in PE women had significant negative correlation with serum Se level (r = -0.353, P < 0.05). A negative correlation was found between erythrocyte catalase activity with birth weight (r = -0.528, P < 0.001). Also, there were a significant negative correlation between serum levels of Cu and Se in the preeclamptic women (r = -0.407, P < 0.05).

CONCLUSION

Our data demonstrate that elevation of lipid peroxides together with impaired antioxidant defense mechanisms and status of trace metals and the presence of possible interrelationship and crosstalk between those parameters may be related at least partly to the pathogenesis of preeclampsia. Additionally, lipid peroxides and blood oxidative imbalance could be part of the cytotoxic mechanisms leading to endothelial cell injury.

Regulation of cyclo-oxygenase gene expression in rat smooth muscle cells by catalase

We have studied, in detail, the effect of catalase, one of the naturally occurring antioxidant enzymes, on the expression of cyclo-oxygenase (COX) mRNA and protein in rat aortic smooth muscle cells (RASMC). The activity of COX enzyme within the cells was also determined. Catalase either alone or in combination with interleukin-1beta (IL-1beta) enhanced mRNA and protein expression for cyclo-oxygenase 2 (COX-2) in a concentration-dependent manner. However, it did not affect the expression of mRNA or protein for cyclo-oxygenase 1 (COX-1). The expression of mRNA for COX-2 induced by catalase was blocked completely by actinomycin D (ACT) or cycloheximide (CHX). In comparison, expression of mRNA for COX-2 stimulated by IL-1beta was inhibited by actinomycin D, but not by cycloheximide. This suggests that induction of the synthesis of mRNA for COX-2 by catalase and IL-1beta involves different mechanisms. In particular, the induction of mRNA for COX-2 by catalase requires on-going protein and RNA synthesis, but the induction following exposure to IL-1beta does not. The increase in expression of mRNA for COX-2 induced by catalase may be related to the ability of catalase to stimulate cyclic AMP response element (CRE) and NF-IL6 transcription factors, but not nuclear factor kappa B (NF-kappaB), for electrophoretic mobility shift assays (EMSA) showed that catalase enhanced nuclear factor binding to cyclic AMP response element and NF-IL6 but not to NF-kappaB. Catalase exerted a biphasic effect on prostaglandin synthesis. At low concentrations it enhanced prostaglandin production, but at high concentrations it tended to inhibit it. These findings suggest that catalase has differential and multiple effects on COX expression and activity in rat aortic smooth muscle cells.

Oxidation of erythrocyte glutathione by monocytes stimulated with interleukin-6. Analysis by 1H spin echo NMR

1H spin echo NMR was used to follow the release of reactive oxygen species (ROS) from human monocytes by monitoring erythrocyte glutathione status, which is sensitive to applied oxidative stress. This allowed the ability of the cytokine interleukin-6 (IL-6) to stimulate release of ROS from monocytes to be assessed in terms of oxidative damage to other cells, providing an estimation of its importance in vivo. It was found that incubation of monocytes with erythrocytes in the presence of IL-6 resulted in oxidation of the erythrocyte glutathione pool, indicating that oxidants are released in sufficient amounts to cause oxidative stress. High levels of IL-6 occurring in plasma of women with severe pre-eclampsia could therefore be responsible for depleted plasma antioxidants and haemolysis. The oxidation of erythrocyte glutathione was inhibited by the presence of the cyclooxygenase inhibitor indomethacin, suggesting that this may be of value in the treatment of oxidative pathologies.

Comparison of selenium levels in pre-eclamptic and normal pregnancies

Abnormal placentation is the likely cause of the slow fetal growth and the high levels of circulating lipid peroxides found in severe pre-eclampsia. These peroxides are probably responsible for the high thromboxane:prostacyclin ratio found in this disease and may participate in the endothelial cell damage which is its most notable feature. Selenium (Se), because of its role in glutathione peroxidase, is suggested to be an important component of the removal system for these damaging peroxides. Serum-Se concentrations have therefore been measured in 19 pairs of pre-eclamptic women and matched controls. Infant birth-weights were recorded. No significant difference was found in the concentrations of Se in pre-eclamptic and control groups. Serum Se was found to be low in both groups. Birthweights were significantly lower in the pre-eclamptic group. The interpretation of serum-Se measurements from the third trimester of a pre-eclamptic pregnancy is complicated by the reduced fetal growth and probable lower Se take-up by the fetus in such a pregnancy. The merits of alternative measurements, such as total intravascular Se, placental Se, or samples from an earlier stage of gestation, are discussed. The importance of factors other than Se to the activity of glutathione peroxidase, and of other antioxidants to pre-eclamptic, is stressed.

Hemostatic changes after dietary coenzyme Q10 supplementation in swine

Improved cardiovascular morbidity and mortality have been observed in several clinical studies of dietary supplementation with coenzyme Q10 (CoQ10). We elucidated the effect of CoQ10 on certain hemostatic parameters that may influence the progression of heart disease. Twelve Yorkshire swine were randomized to receive diet supplementation with either CoQ10 or placebo for 20 days. Blood samples were obtained at baseline and at the end of the feeding period. At the end of the protocol, there were no significant differences in hemostatic parameters in the placebo group. A significant increase in total serum CoQ10 level (from 0.39 +/- 0.06 to 0.96 +/- 0.04 microgram/ml, p < 0.001) was noted after the feeding period in the CoQ10-supplemented group. We observed significant inhibition of ADP-induced platelet aggregation (-9.9%) and a decrease in plasma fibronectin (-20.2%), thromboxane B2 (TXB2, -20.6%), prostacyclin (-23.2%), and endothelin-1 (ET-1, -17.9%) level. There were no changes in the plasma concentrations of the natural antithrombotics [antithrombin-III (AT-III), protein S, and protein C] after CoQ10 supplementation. CoQ10 supplementation in a dose of 200 mg daily is associated with mild antiaggregatory changes in the hemostatic profile. Clinical beneficial effects of CoQ10 may be related in part to a diminished incidence of thrombotic complications.

Normal superoxide dismutase (SOD) gene in pregnancy-induced hypertension: is the decreased SOD activity a secondary phenomenon?

Reactive oxygen species (ROS) have been implicated in the pathogenesis of pregnancy-induced hypertension (PIH). A genetic factor is also thought to be associated with the disease. The aim of the present study was to investigate whether decreased superoxide dismutase (SOD) activity in PIH resulted from gene abnormalities. Fourteen patients with PIH were enrolled in the study. Normal pregnant women and normal nonpregnant women served as controls. Genomic DNA and mRNA were isolated from white cells and subjected to Southern and Northern blot analysis with a 600 bp CuZn-SOD probe. SOD activity was also determined in the white blood cells and red blood cells. The results showed that SOD activity was significantly reduced in patients with PIH compared to both control groups. There were no significant differences in the size of the CuZn-SOD gene and its expression between the patients with PIH and the controls. This study confirmed that there was a decreased SOD activity in PIH but revealed neither major structural changes in the genomic DNA nor mRNA size of CuZn-SOD. Our results suggest that the decreased SOD levels in PIH are not due to abnormalities in the CuZn-SOD gene and are an acquired phenomenon which occurs during the development of the disease.