Researchers at Johns Hopkins University (JHU: Baltimore, MD, USA) studied the effects of resveratrol--an enriched bioactive polyphenol found in red wine--in cultured mouse cortical neuronal cells. The researcher found that the resveratrol selectively induced heme oxygenase 1 (HO1) in the cells in a dose- and time-dependent manner, providing neuroprotection from free radical or excitotoxicity damage. This protection was lost when the cells were treated with a protein synthesis or heme oxygenase inhibitor, suggesting that HO1 induction was at least partially required for resveratrol's prophylactic properties to take effect.
The researchers then fed study mice a single modest dose of resveratrol, and two hours later induced a stroke in an optimized ischemic-reperfusion stroke model. The researchers found that the resveratrol pretreatment protected the mice in a dose-dependent fashion. According to the researchers, the results suggest that the amount of resveratrol needed to provide the neuroprotective effect could be quite small, as the suspected beneficial mechanism is indirect; resveratrol and its metabolites may not be directly shielding brain cells from free radical damage, but could instead be prompting the cells to defend themselves. The study was published ahead of print on April 8, 2010, in Experimental Neurology.
"Our study adds to evidence that resveratrol can potentially build brain resistance to ischemic stroke. It's not likely that brain cells can have high enough local levels of resveratrol to be protective,” said lead author Sylvain Doré, Ph.D., and colleagues of the department of anesthesiology and critical care medicine. "The resveratrol is needed to jump-start this protective enzymatic system that is already present within the cells; even a small amount may be sufficient.”
Red wine has several purported health benefits, and moderate wine consumption has been linked to a lowered incidence of cardiovascular disease. This phenomenon has been named the French paradox, since despite diets high in butter, cheese, and other saturated fats, the French have a relatively low incidence of cardiovascular events, which some have attributed to the regular drinking of red wine.
While the concentration of resveratrol in wine seems too low to account for the French Paradox, an additional group of polyphenols, known as oligomeric procyanidins, could offer the greatest degree of protection to human blood-vessel cells. Tests with 165 types of wine have shown that these are found in greatest concentration in European red wines from certain areas, which correlates with longevity in those regions. The highest procyanidins are found in wines from the Tannat grape, grown in the Gers area of southwest France and in Uruguay.
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