Martes 27 de Noviembre de 2001, Ip nš 8

Researchers find gene that boosts longevity
Researchers have found a gene that protects cells from a destructive form of oxygen and could possibly give mammals a longer life span. The finding could lead to drugs to help cells resist aging.

In laboratory studies at the National Institutes of Health, researchers studied mice that had been bred to lack a specific gene linked to neutralizing the effects of oxygen free radicals. The mice tended to have a life span about 40 percent shorter than mice with normal genes.

The gene makes an enzyme called methionine sulfoxide reductase, or MsrA, which studies show helps to protect cells from being damaged by a type of highly reactive oxygen, said Jackob Moskovitz, a researcher at the National Heart, Lung and Blood Institute at the NIH.

Oxygen free radicals are produced during cell metabolism. These reactive oxygen molecules are able to damage genes and cause changes in proteins.

Moskovitz said that the MsrA enzyme neutralizes the oxygen free radicals and repairs proteins that have been damaged. He said the enzyme, in an action still not understood, also protects brain cells that are damaged by oxygen stress.

"It is not clear which biological pathways (actions) are involved, but it is clear in studies on human T-cells (a type of blood cells) that this enzyme is important" in restoring to their normal condition any proteins damaged by oxygen stress, said Moskovitz.

In the study, the NIH researchers closely followed the lives of 17 mice that lacked the MsrA gene and 22 mice that had at least one MsrA gene.

Mice with just one of the genes had an average life span of 672 days, while mice with normal genes had an average life span of 680 days. But the mice missing both copies of the MsrA gene had an average life span of only 409 days, about 40 percent less.

In addition, Moskovitz said that some mice lacking the MsrA gene began walking on their tiptoes when they were 6 months old. He said this indicates that these animals developed some sort of brain damage and suggests that the gene plays a role in protecting the brain from oxygen stress. The precise action of the MsrA enzyme in the brain is not clear, he said.

Moskovitz said the next step in his study is to develop a mouse with genes that cause it to make a superabundance of the MsrA enzyme.

"If we overexpress the enzyme in mice and the mice live 50 percent longer, for instance, it would be very suggestive that this would be very useful in trying in humans," he said. Moskovitz said it will take at least four years before researchers know the effects of high levels of MsrA enzyme.

Raj S. Sohal, a University of South California scientist researching the effects of aging, said the Moskovitz study "was very interesting work."

"They are on the right path," Sohal said of the NIH researchers. He noted, however, that it will be many years before such work could benefit humans.

"These are basic scientists. We are all basic scientists in this field," he said.


  Noviembre de 2002. CNN.