Author: Yangguang Ou
Institution: Florida State University
Date: December 2008
A recent study at Harvard University has suggested that a probable mechanism to slow the aging process might be packed into a tiny protein called sirtuin, which can be activated by a natural chemical known as resveratrol.
Resveratrol (found in red wine, the skin of grapes, the crust of walnuts and peanuts, peanut butter, pistachios, and several other foods) has long been a center of scientific attention. Many have postulated it to be one of the factors that caused the "French paradox," a baffling phenomenon in which the French enjoyed a high-fat diet yet had fewer cases of heart diseases than the Americans did.
Resveratrol activates the protein sirtuin that repairs damages to chromosomes, the compacted form of genetic materials, as well as suppresses the large amount of "silent" genes. These silent genes are normally turned off, meaning they are not expressed as proteins, in order to avoid chaos in the body. The role of sirtuin is to pack these DNA strands into tight conformations as to prevent transcription. Scientists believe that as people age, the integrity of the chromosomes is compromised and thus increasing quantities of sirtuin proteins are needed to keep things under control. However, the limiting number of these proteins in the body may not keep up with the degradation process.
Sirtris, a pharmaceutical company founded by David Sinclair, a professor at Harvard Medical School, and his colleagues has developed a number of chemicals that mimic resveratrol. The most recent findings, as published in the journal Cell Metabolism on Wednesday, reported that one of the chemicals was able to prevent mice on fatty diets from getting obese. Not only that, it also increased endurance of the mice on the treadmills.
"The critical protein controls both which genes are off and on as well as DNA repair; it's used for both processes, and that's the catch," said Sinclair to eFluxMedia.
Despite the apparent success of these medicinal discoveries, scientists are still uncertain as to the possible side effects of these drugs and whether humans will react to it the same way that the mice did. "Resveratrol is a powerful agent," The New York Times reports, "that has many different effects, only some of which are exerted through sirtuin." Thus, the effects of these mimicking molecules are still under question. Ronald Evans, a biologist at Salk Institute, said in an email to The New York Times: "The new report was provocative but did not prove the case that the relocation of sirtuin was a cause of aging." Sinclair agrees that the cause-and-effect relationship is not officially established. "We are careful not to say this is the cause of aging, but based on everything we know it's not a bad hypothesis. It would be nice to test aging in mice that lack the sirtuin gene, as Dr. Evans proposed, but they die too young," he said.
Sinclair has been taking daily dosage of resveratrol since its discovery five years ago of activating sirtuin: "I'm still taking it, and I feel great, but it's too early to say if I'm young for my age."
Written by: Yangguang Ou
Edited by: Brittany Raffa
Published by: Hoi See Tsao