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And next year in Canada, 160 investigators from several universities will launch the Canadian Longitudinal Study on Aging, which will follow 50,000 men and women 45 to 85 years old for at least two decades, probing the subjects' biological, psychological, social and economic changes over time. It is being billed as the most comprehensive aging study ever undertaken.
The CIHR, Canada's main medical-research funding body, spent $136-million on all age-related research in the past year, more than five times what it spent in 2000-2001. The Institute of Aging now gets roughly 14 per cent of CIHR's total budget, compared to 6 per cent nine years ago.
Progress has been so rapid that many researchers now see aging as a series of degenerative diseases than can be delayed or even prevented. The prospect has even sparked serious debate about the limits of the human lifespan, with a bold few predicting that the average North American girl born today will live to be 100.
"We have all the tools — we understand genes, metabolism, and these things are much easier [now] to measure and manipulate," the California-based Dr. Ames says. "I think we can push back all the degenerative diseases of aging. I think we can add a few years to everyone's life."
90 year old Barbara Roberts puts groceries away at her home in Vancouver. Roberts lives independently in a small arts and craft house on the East Vancouver. (Lyle Stafford/Special to the Globe and Mail)
Internet Links
- World's oldest known person: Jeanne Louise Calment, born 1875, died 1997 at age 122
- Louise Calment photo gallery
- Oldest known Canadian: Marie-Louise Meilleur
- Wikipedia: World's oldest list
Funding fuelled
In Canada, the CIHR helped to kick-start the process in 2001 when it put out a call for aging-research proposals. Angela Brooks-Wilson, a senior scientist at the B.C. Cancer Agency in Vancouver, was researching genetic susceptibilities to cancer, but she realized that she could tweak her project to qualify for the new funds.
"It shows how granting agencies can foster research in a particular area," she says, adding, jokingly, "People at the granting agencies are aging too."
She broadened her planned study of elderly people who were free of cancer and decided to analyze the genes of seniors who had not developed any major disease. Dr. Brooks-Wilson says human lifespan depends largely on environmental and lifestyle factors, but estimates genes account for about 30 per cent of the question. By the end of 2002, the CIHR had granted her $1.25-million over five years to study such a cohort of "super seniors."
These 550 people from the greater Vancouver area, selected with information from the B.C. Ministry of Health, range in age from 85 to 105 and have never developed cancer, pulmonary disease, Alzheimer's, diabetes or cardiovascular disease.
Two-thirds of them are women (who tend to live longer than men) such as Barbara Roberts, who lives alone in the city's east end and still shovels her own snow at the age of 90. "She's amazing, energetic," says Dr. Brooks-Wilson. "A live wire."
Among the super seniors, researchers are looking at 25 different genes involved in metabolism and tumour suppression. They are comparing them with DNA from a control group of 550 randomly selected men and women between the ages of 40 and 50 — two-thirds of whom, statistics suggest, will not live to be 85. They are investigating whether the super seniors carry a common genetic trait that most of the control group does not.
Results are expected early this year. Meanwhile, the B.C. group has already found something of interest in the telomeres of the super seniors.
Telomeres are one of the hottest molecules in medicine. Like plastic caps on the ends of shoelaces, telomeres are tails at the ends of chromosomes that keep genetic information from "fraying."
But telomeres are also biological time bombs: They grow shorter each time a cell a divides; and the longer we live, the more each cell has divided.
The telomeres, which are actually a certain repeated sequence of DNA (TTAGGG), eventually wear down to unstable nubs. At that point, cells start to break down and die — and so, it seems, bones thin, chins sag and cancers sprout.
Naturally, there's a big interest in finding ways to turn back the telomere clock.
As a group the super seniors do not have especially long telomeres, says Dr. Brooks-Wilson, but their telomeres do seem to be of a generally uniform length, while the middle-aged control group shows much greater variation.
The theory is that if a telomere is too long, the cell will divide more times than it should, increasing the risk of cancer. But if a telomere is too short, the cell could suffer early genetic damage, also leading to disease.
