The Oxygen Club of California held its annual scientific conference, co-sponsored by LPI, in Santa Barbara, California, in mid-April. Oxidants and Antioxidants in Biology featured 35 presentations in four sessions: "Obesity, the Metabolic Syndrome, and Oxidative Stress"; "Obesity, Uncoupling Proteins, and Micronutrient Action"; "Dietary Modulation of Cell Signaling Pathways"; and "Mitochondrial Function, Aging, and Disease."
Addressing obesity, several speakers noted that it is associated with inflammation and oxidative stress, which can be ameliorated with weight loss and decreased macronutrient intake. Additionally, fish oil (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) exerts antiinflammatory effects that may reduce the risk of heart disease in obese individuals. Insulin resistance and inflammation are also associated with obesity in pregnant women, increasing the risk for gestational diabetes. Insulin resistance, oxidative stress, and dysfunction of the insulin-producing pancreatic beta cells may be attenuated with alpha-lipoic acid and acetyl-L-carnitine. Selenium supplementation in rats alleviated inflammation associated with liver damage by regulating manganese superoxide dismutase, an endogenous antioxidant enzyme.
Other speakers addressed how flavonoids, phytochemicals, and other dietary constituents affect cell-signaling pathways, contributing to the reduction of oxidative stress and the prevention of cancer. For example, catechins in tea may inhibit growth factors implicated in cancer. In rats, white tea and certain catechins in tea provide some protection against colon tumors induced by "cooked-meat mutagens." Resveratrol in wine and grapes and isothiocyanates in cruciferous vegetables induce apoptosis, or programmed death, in cancer cells. The omega-3 fat DHA suppressed amyloid plaque formation in the brain when fed to mice that mimic Alzheimer's disease. Selenium compounds block the cell cycle and lead to apoptosis in melanoma cells and also inhibit metastasis of injected melanoma in mice. Additionally, acetyl-Lcarnitine inhibited inflammation and oxidative stress in rat astrocytes (cells in the nervous system that support neurons). Astaxanthin, an orange-colored carotenoid, ameliorates oxidative stress in the kidney cells of diabetic mice.
In the final session, scientists discussed mitochondria, the energy-producing organelles in cells that can be damaged by oxidants generated within the mitochondria themselves. Such damage can be attenuated by glutathione, an endogenous antioxidant, and glutathione peroxidase, an enzyme that inhibits lipid oxidation in mitochondria. Mitochondrial dysfunction and defects have been implicated in neurodegenerative diseases like Parkinson's. Additionally, loss of calcium regulation associated with ischemia and reperfusion results in increased oxidative stress in mitochondria, and the signaling molecule nitric oxide plays a role in mediating ischemic damage. (Ischemia refers to the partial or complete obstruction of an artery, resulting in reduced blood flow and oxygen supply to the heart and other tissues. Symptoms may include angina, pain in the arm, shortness of breath, and nausea.)
Last updated June, 2006