TORONTO--Researchers have found a gene that helps explain why some people live to a ripe old age of 100. The finding, reported on 27 October here at the annual meeting of the American Society of Human Genetics, expands on earlier work showing that these oldsters have an unusual profile of lipids in their blood.
Nir Barzilai of Albert Einstein College of Medicine in New York City and colleagues have been studying more than 300 Ashkenazi Jews with an average age of 98, their offspring, and age-matched controls to find clues to long life. As they reported a year ago, their subjects' blood contains especially large lipoprotein particles, which are normally seen only in young, exercising adults (ScienceNOW, 14 October 2003). They also tended to have a mutation in a gene called cholesteryl ester transfer protein, or CETP, that raises levels of the “good” kind of cholesterol, high density lipoprotein (HDL) and increases particle size of both HDL and low density lipoprotein (LDL), the bad kind.
At the meeting, team member Gil Atzmon reported that a second gene appears to protect the centenarians as well. The gene codes for a lipoprotein called apolipoprotein CIII (ApoC-III) that is a component of LDL. ApoC-III also stimulates production of harmful lipids called triglycerides, and high levels raise the risk of cardiovascular disease. As with CETP, the centenarians were more likely to have two copies of a certain version of ApoC-III than were controls (25% compared to 11%). Those with the ApoC-III mutation had lower blood levels of ApoC-III protein, large lipid particles, and lower rates of hypertension and resistance to insulin, a sign of aging. The "most dramatic" result, says Barzilai, emerged when they looked at this ApoC-III mutation in blood samples from a separate group of Ashkenazis: Those with the ApoC-III copies tended to live 4 years longer, on average.
The finding "makes sense because both [genes] are involved in lipid profiles," says Samir Deeb of the University of Washington, Seattle.
Longevity Genes Project