Free radical biology & medicine
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Free Radic. Biol. Med. · Jan 2009
Randomized Controlled Trial Comparative Study Clinical Trial20-HETE and F2-isoprostanes in the metabolic syndrome: the effect of weight reduction.
20-Hydroxyeicosatetraenoic acid (20-HETE) is a cytochrome P450 metabolite of arachidonic acid that regulates vascular function and sodium homeostasis. Studies showing an association between 20-HETE excretion, raised BMI, and oxidative stress suggest that 20-HETE may be important in the development of cardiovascular disease in the metabolic syndrome (MetS). We investigated whether 20-HETE and F(2)-isoprostanes (markers of oxidative stress) were altered in the MetS before and after weight reduction. ⋯ In a randomized controlled trial, 42 participants with the MetS were assigned to 16 weeks of weight maintenance or a 12-week weight-loss program followed by 4 weeks weight stabilization. Relative to the weight-maintenance group, a 4-kg loss in weight resulted in a 2-mm Hg fall in blood pressure (BP) but did not alter urinary or plasma 20-HETE or F(2)-isoprostanes. 20-HETE and oxidative stress may be important mediators of cardiovascular disease risk in the MetS. Although a 4% reduction in body weight reduced BP, there were no changes in plasma or urinary 20-HETE or F(2)-isoprostanes.
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Free Radic. Biol. Med. · May 2006
Randomized Controlled TrialVitamin supplementation does not protect against symptoms in ozone-responsive subjects.
Vitamin supplements have been reported to reduce the magnitude of symptoms in subjects exposed to oxidant air pollution. To confirm whether supplementation with vitamins C and E could reduce lung function decrements, airway inflammation, and epithelial injury in subjects sensitive to ozone, a double-blinded, crossover control study was performed. Fourteen ozone-responsive subjects were randomly exposed to both air and ozone (0.2 ppm for 2 h) after 7 days of either placebo treatment or supplementation with vitamin C (500 mg/day) and E (100 mg/day). ⋯ Similarly, ozone-induced neutrophilia were of a similar magnitude after both treatments (P < 0.05). This lack of protection was observed despite elevated plasma vitamin C (+60.1%) and vitamin E (+51.4%) concentrations following supplementation, and increased vitamin C concentrations in the airways after supplementation following ozone exposure. These data do not therefore support the contention that acute ozone-induced symptoms can be attenuated through the use of dietary antioxidants in well-nourished individuals.
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Free Radic. Biol. Med. · Aug 2004
Randomized Controlled Trial Clinical TrialFlavanol-rich cocoa drink lowers plasma F(2)-isoprostane concentrations in humans.
Flavan-3-ols are potent antioxidants in vitro, but convincing evidence for antioxidant action in vivo is lacking. We examined whether an oxidative stress-mediated increase in plasma F(2)-isoprostanes is counteracted by a flavanol-rich cocoa beverage. Twenty volunteers were examined in a comparative randomized double-blind crossover design with respect to ingestion of high-flavanol cocoa drink (HFCD; 187 mg flavan-3-ols/100 ml) vs. low-flavanol cocoa drink (LFCD; 14 mg/100 ml). ⋯ The difference in F(2)-isoprostanes 2 and 4 h after intake of HFCD vs. LFCD became statistically significant when the intake was combined with physical exercise (P < 0.01, ANOVA). We conclude that dietary flavanols, using cocoa drink as example, can lower the plasma level of F(2)-isoprostanes, indicators of in vivo lipid peroxidation.
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Free Radic. Biol. Med. · Jan 1997
Randomized Controlled Trial Clinical TrialThe effects of intravenous antioxidants in patients with septic shock.
Oxidative stress is implicated in septic shock. We investigated the effect of intravenous antioxidant therapy on antioxidant status, lipid peroxidation, hemodynamics and nitrite in patients with septic shock. Thirty patients randomly received either antioxidants (n-acetylcysteine 150 mg/kg for 30 min then 20 mg/kg/h plus bolus doses of 1 g ascorbic acid and 400 mg alpha-tocopherol) or 5% dextrose. ⋯ Systemic vascular resistance index decreased at 120 min in the antioxidant treated patients (p = .003). The effect of antioxidants on hemodynamic variables has not previously been reported. Antioxidant administration may be a useful adjunct to conventional approaches in the management of septic shock.