An experimental drug designed to kick-start growth hormones in humans shows signs of helping the elderly age without becoming too frail, researchers reported Wednesday, while another team found clues to healthy longevity in the blood of 100-year-old women.
The reports, presented to a meeting of the International Congress of Neuroendocrinology, gave a snapshot of some of the progress in the growing field of aging research.
By 2010, census experts predict more than 40 million people will be over age 60 in the United States. Not all will be in good shape.
"Some people age quite successfully and can live to very old ages with relatively little impairment, and other people do not age as successfully, and the question is why," Robert Gibbs of the University of Pittsburgh School of Pharmacy told a news conference.
Dr. George Merriam of the University of Washington/VA Puget Sound Health Care System and colleagues tested Pfizer's experimental drug capromorelin in 395 men and women aged 65 to 84. All were frail in some way, having fallen or lost grip strength or having slowed down in walking.
Capromorelin is a growth hormone stimulator. It causes the body to secrete human growth hormone in a way seen at puberty and in young adulthood.
In young adults, those pulses of growth hormone are associated with a buildup of lean muscle mass and strength, and elderly people have much lower levels of the hormone — and less lean muscle mass.
Patients who got the drug gained an average of 3 pounds in lean muscle mass after six months, and also were better able to walk a straight line — a test of balance, strength and coordination.
A year later, they also showed an improvement in stair climbing, Merriam told the meeting at the University of Pittsburgh.
He said Merck and Co. was working on a similar drug.
"Drugs in this category have the promise of improving physical function ... thereby prolonging older people's ability to continue to live independently," Merriam told reporters.
It would not be easy to license such a drug, he cautioned.
"It is very difficult to get a drug for normal aging on the market, because the FDA (the U.S. Food and Drug Administration) does not consider aging to be a disease and sets the bar extremely high," Merriam said.
A study by Polish researchers suggested other routes of research.
Dr. Agnieszka Baranowska-Bik and colleagues at the University of Poland studied 133 women, including 25 aged from 100 to 102, 26 women aged 64 to 67 and 45 women aged 20 to 43, as well as younger obese women.
The women aged over 100 had measurably higher levels in their blood of adiponectin, a protein produced by fat tissue, Baranowska-Bik told the meeting.
Healthier 100 year olds
"We found that our centenarian women were healthier than other elderly women," she told the news conference. They had lower cholesterol and better control of blood sugar — a measure of tendency to diabetes, she said.
They were also healthier than the much younger but overweight women.
It is not clear if the women's adiponectin was a cause or effect of healthier lifestyle. The protein counteracts inflammation, which is linked with disease, helps keep vessels clear of fatty deposits and plays an important role in metabolism.