Inside Science News Briefs
- From: Sam Wormley <swormley1@xxxxxxxxx>
- Date: Mon, 01 Dec 2008 20:41:44 GMT
Inside Science News Briefs
December 1, 2008
By Jim Dawson
Inside Science News Service
Exercise Keeps Your Brain Young, Even If You're Old
Older adults who exercise regularly have more small blood vessels and more blood flow in their brains than older people who don't exercise, researchers at the University of North Carolina, Chapel Hill, discovered after comparing brain scans of the two groups. Blood flow supplies the brain with nutrients, and the loss of small blood vessels in the brain, a normal process of aging, leads to the death of some brain cells. "Our results show that exercise may reduce age-related changes in brain vasculature [small blood vessels] and blood flow, said Feraz Rahman, who presented the research Monday at the annual meeting of the Radiological Society of North America. "Our studies have shown that exercise prevents cognitive decline in the elderly [and] the blood vessel and flow differences may be one reason."
The scans were done on the brains of 12 healthy adults between the ages of 60 and 76. Six had participated in aerobic exercise for three or more hours per week for the last 10 years, and six had exercised less than one hour per week. Using 3D imaging, the researchers found fewer small blood vessels in the brains of the inactive group, along with more unpredictable blood flow. The active group had more small blood vessels and improved blood flow, which the study's lead author, J. Keith Smith of UNC's School of Medicine, said show the "importance of regular exercise to healthy aging."
Yeast Reveals What Makes You Age
For the past decade researchers have known that a particular type of gene found in yeast cells, called sirtuin, regulated which other genes switched on and off in individual cells. The sirtuin gene also repaired breaks in DNA, the double-helix shaped structure found in every cell that holds the blueprint for life. When the sirtuin became too busy fixing breaks in the DNA that typically accumulate over time, it did a less efficient job of regulating which genes in the cell turned on and off. This lack of efficiency caused the yeast cells to age.
New research published in the journal Cell by David Sinclair, of the Harvard Medical School in Boston, discovered that the same process, involving the same type of sirtuin gene, occurs in mammals. "This is the first potentially fundamental, root cause of aging that we've found," Sinclair said. "There may very well be others, but our finding that again in a simple yeast cell is directly relevant to aging in mammals comes as a surprise."
After making the link between yeast and mammals through studies of mice, the researchers wondered what would happen if they put more of the sirtuin into aging mice. "Our hypothesis was that with more sirtuins, DNA repair would be more efficient, and the mouse would maintain a youthful pattern of gene expression into old age," said Philipp Oberdoerffer, a co-investigator in the study. That is exactly what happened, the researchers said.
Leonard Guarente, a biologist at the Massachusetts Institute of Technology in Cambridge, who was not involved in the study, said the research "should lead to new approaches to protect cells against the ravages of aging." Oberdoerffer said, "We see here, through a proof-of-principal demonstration, that elements of aging can be reversed."
This story is provided for media use by the Inside Science News Service, which is supported by the American Institute of Physics, a not-for-profit publisher of scientific journals. Contact: Jim Dawson, news editor, at jdawson@xxxxxxx
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