July 12, 2010

Longevity Gene Linked To Memory, Brain Power

According to a study published on Sunday, a gene linked to increased life span through calorie restriction also appears to play a critical role in boosting memory and brain power.

Laboratory experiments have proven that a protein encoded by the SIRT1 gene can help slow the aging process in rodents.

According to the new findings, the enzyme, which is known as Sirtuin1 in humans, seems to enhance memory and nerve-cell development in the brain as well.

The researchers wrote in the journal Nature that the work could provide leads for drugs to combat Alzheimer's and other debilitating neurological diseases.

The team demonstrated earlier that Sirtuin1 boosted neuron survival in mice that are generally modified to mimic certain degenerative brain disorders.

"We have now found that SIRT1 activity also promotes memory and plasticity," Li HueiTsai, the team leader, said, referring to the ability of healthy brain cells to interconnect.

"This result demonstrates a multi-faceted role of SIRT1 in the brain, further highlighting its potential as a target for the treatment of conditions with impaired cognition."

Tsai examined behavior and brain development of mice deficient in the SIRT1 gene during the experiments.

The mice, when compared to normal mice, reacted poorly to electrical stimulation in the hippocampus, which is critical to long-term memory and spatial navigation.  The hippocampus in Alzheimer's patients is one of the first regions of the brain to be damaged.

The gene-altered lab mice also had reduced density of neuron development, which is a key measure of brain activity.

They were less able to discriminate old from new objects in memory tests.

"SIRT1 deficient mice are impaired in all three memory paradigms compared to control mice," Tsai explained in an email written to AFP news.

The study also discovered a previously unknown mechanism:  by keeping certain gene regulators called microRNAs in check, the SIRT1 gene allows the memory-enhancing proteins to be expressed.

Tsai cautioned that the results are preliminary and that it is still too early to design clinical trials with humans.

She said that the study did open up the intriguing possibility that Sirtuin1 enzymes could one day be used to turbocharge memory and brain functions even in healthy people.

"Activation of sirtuins can be mildly beneficial in humans," she said.

Other recent studies have found that the gene and enzyme it produces are part of a feedback system that enhances cell survival during times of stress, especially a lack of food.


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