[ExI] Fwd: Rapamycin Extends Lifespan Of Old Mice: 28 To 38 Percent
hkhenson at rogers.com
Sat Jul 11 05:01:17 UTC 2009
This is impressive.
>Resent-From: cryonet-list at cryonet.org
>CryoNet - Fri 10 Jul 2009
>[Note: A special more bioavailable microencapsulated form of
>rapamycin was used.]
>Easter Island compound extends lifespan of old mice, scientists
>report in Nature
>Posted: Wednesday, July 08, 2009
>Contact: Will Sansom, (210) 567-2579
>UT Health Science Center, other centers reach same result: 28%-38% longer life
>SAN ANTONIO (July 8, 2009)-The giant monoliths of Easter Island are
>worn, but they have endured for centuries. New research suggests
>that a compound first discovered in the soil of the South Pacific
>island might help us stand the test of time, too.
>Today in the journal Nature, The University of Texas Health Science
>Center at San Antonio and two collaborating centers reported that
>the Easter Island compound - called "rapamycin" after the island's
>Polynesian name, Rapa Nui - extended the expected lifespan of
>middle-aged mice by 28 percent to 38 percent. In human terms, this
>would be greater than the predicted increase in extra years of life
>if cancer and heart disease were both cured and prevented.
>The rapamycin was given to the mice at an age equivalent to 60 years
>old in humans.
>The studies are part of the National Institute on Aging (NIA)
>Interventions Testing Program, which seeks compounds that might help
>people remain active and disease-free throughout their lives. The
>other two centers involved are the University of Michigan at Ann
>Arbor and Jackson Laboratory in Bar Harbor, Maine.
>The Texas study was led by scientists at two institutes at the UT
>Health Science Center: the Institute of Biotechnology (IBT) and the
>Barshop Institute for Longevity and Aging Studies.
>"I've been in aging research for 35 years and there have been many
>so-called 'anti-aging' interventions over those years that were
>never successful," said Arlan G. Richardson, Ph.D., director of the
>Barshop Institute. "I never thought we would find an anti-aging pill
>for people in my lifetime; however, rapamycin shows a great deal of
>promise to do just that."
>Discovered in the 1970s, rapamycin was first noted for its
>anti-fungal properties and later was used to prevent organ rejection
>in transplant patients. It also is used in stents, which are
>implanted in patients during angioplasty to keep coronary arteries
>open. It is in clinical trials for the treatment of cancer.
>The new aging experiments found that adding rapamycin to the diet of
>older mice increased their lifespan. The results were the same in
>Texas, Michigan and Maine.
>"We believe this is the first convincing evidence that the aging
>process can be slowed and lifespan can be extended by a drug therapy
>starting at an advanced age," said Randy Strong, Ph.D., who directs
>the NIA-funded Aging Interventions Testing Center in San Antonio. He
>is a professor of pharmacology at the UT Health Science Center and a
>senior research career scientist with the South Texas Veterans
>Health Care System.
>The findings have "interesting implications for our understanding of
>the aging process," said Z. Dave Sharp, Ph.D., director of the
>Institute of Biotechnology and professor and chairman of the Health
>Science Center's Department of Molecular Medicine.
>"In addition," Dr. Sharp said, "the findings have immediate
>implications for preventive medicine and human health, in that
>rapamycin is already in clinical usage."
>Aging researchers currently acknowledge only two life-extending
>interventions in mammals: calorie restriction and genetic
>manipulation. Rapamycin appears to partially shut down the same
>molecular pathway as restricting food intake or reducing growth factors.
>It does so through a cellular protein called mTOR (mammalian target
>of rapamycin), which controls many processes in cell metabolism and
>responses to stress.
>A decade ago, Dr. Sharp proposed to his colleagues that mTOR might
>be involved in calorie restriction. "It seemed like an off-the-wall
>idea at that time," Dr. Richardson said.
>In 2004, a year after the launch of the NIA Interventions Testing
>Program, Dr. Sharp submitted a proposal that rapamycin be studied
>for anti-aging effects. The proposal was approved, and testing
>centers in San Antonio and elsewhere began to include rapamycin in
>the diets of mice.
>The male and female mice were cross-bred from four different strains
>of mice to more closely mimic the genetic diversity and disease
>susceptibility of the human population.
>Dr. Strong soon recognized a problem: Rapamycin was not stable
>enough in food or in the digestive tract to register in the animals'
>blood level. He worked with the Southwest Research Institute in San
>Antonio to improve the bioavailability of the compound through a
>process called microencapsulation. The reformulated drug was stable
>in the diet fed to the mice and bypassed the stomach to release in
>the intestine, where it could more reliably enter the bloodstream.
>The original goal was to begin feeding the mice at 4 months of age,
>but because of the delay caused by developing the new formulation,
>the mice were not started until they were 20 months old - the
>equivalent of 60 years of age in humans.
>The teams decided to try the rapamycin intervention anyway.
>"I did not think that it would work because the mice were too old
>when the treatment was started," Dr. Richardson said. "Most reports
>indicate that calorie restriction doesn't work when implemented in
>old animals. The fact that rapamycin increases lifespan in
>relatively old mice was totally unexpected."
>Added Dr. Strong: "This study has clearly identified a potential
>therapeutic target for the development of drugs aimed at preventing
>age-related diseases and extending healthy lifespan. If rapamycin,
>or drugs like rapamycin, works as envisioned, the potential
>reduction in overall health cost for the U.S. and the world will be enormous."
>Leaders of the other interventions testing centers are Richard
>Miller, M.D., Ph.D., of the University of Michigan and David
>Harrison, Ph.D., at the Jackson Laboratories.
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