TUESDAY, May 1 (HealthDay News) — Researchers have found new evidence showing that resveratrol, a compound found in red wine, may play a role in preventing cell aging.
The study in rodents found that when mice had a particular gene — SIRT1 — knocked out, or turned off, resveratrol had no effect on them. But tests of muscle tissue in mice with a normal SIRT1 gene that were given resveratrol found that the substance boosted mitochondrial function.
Mitochondria provide the energy that cells need to function. A decrease in mitochondrial energy production has been linked to a variety of diseases, including diabetes and Alzheimer’s disease, as well as to the aging process itself, said senior study author David Sinclair, a professor of genetics at Harvard Medical School in Boston.
But don’t go reaching for that Chianti yet. Yes, resveratrol is found in the skin of red grapes. But “the amounts we gave to our mice would be like drinking 100 glasses of red wine a day,” Sinclair said.
Instead, the goal is to develop synthetic resveratrol compounds that activate SIRT1 and could be taken as medication. “My colleagues are in the middle of developing better molecules that we hope will be medicines that will be used to treat diseases of aging, not to extend lifespan, though that may be a side effect,” Sinclair said.
The study is in the May 1 issue of Cell Metabolism.
While previous studies have also suggested that resveratrol may have anti-aging properties, the precise mechanism of resveratrol has been controversial. Several studies, including work with yeast, worms and flies, have found that resveratrol acts on a class of seven genes known as sirtuins and, in human cells, SIRT1 in particular.
But other researchers have argued that resveratrol may work by activating a separate energy pathway called AMPK, which is also related to mitochondrial energy production but does not involve sirtuin genes.
Testing the effect of resveratrol on SIRT1 in mice was difficult, Sinclair said. Mice that have their SIRT1 gene deleted are born with developmental defects and are unsuitable for experiments, he explained.
So Sinclair and two graduate students, Nathan Price and Ana Gomes, worked for years to come up with a method for knocking out SIRT1 in healthy adult mice.
“Our paper found you absolutely require the SIRT1 gene for resveratrol to improve the metabolism of the mice,” Sinclair said.
The paper also showed that the AMPK pathway was activated in mice given high doses of resveratrol, yet there was no benefit to mitochondrial function. There was no effect on AMPK in mice given a lower dose of resveratrol.
Sinclair is co-founder and a consultant for Sirtris Pharmaceuticals Inc., which is developing resveratrol-like molecules for use as treatment for age-related diseases. In 2010, according to news reports, the company, which is owned by GlaxoSmithKline, halted clinical trials of resveratrol, but Sinclair said the company continues to develop improved synthetic molecules.
George Vlasuk, CEO of Sirtris, said the new findings offer the “first definitive evidence” for a direct link between SIRT1 and the metabolic benefits of resveratrol.
“The work by [first author] Price et al. strongly supports the basic rationale being pursued at Sirtris, which focuses on the development of small-molecule compounds that directly activate the enzymatic activity of SIRT1 as a new therapeutic approach to many diseases of aging,” Vlasuk wrote in an email to the journal.
Philippe Marambaud, an investigator at the Litwin-Zucker Center for Research in Alzheimer’s Disease and Memory Disorders at the Feinstein Institute for Medical Research in Manhasset, N.Y, said the new research adds to a body of evidence that resveratrol can potentially combat aging by boosting mitochondrial activity.
“In this study, by using an elegant adult-inducible SIRT1 knock-out mouse model, the authors now provide compelling evidence that SIRT1 is required in vivo [in the animal] for the effect of resveratrol on AMPK activation and on mitochondrial function,” Marambaud said.
While studies involving animals can be useful, they frequently fail to produce similar results in humans.
“A mouse model is not a human being, especially when you are genetically manipulating this animal model, you want to be very careful,” Marambaud said. “This field has been extremely controversial. We should be very careful about claiming the importance of resveratrol for medical purposes. We have to wait and see, but this study is a big step forward.”
The U.S. Centers for Disease Control and Prevention has more on healthy aging.
SOURCES: David Sinclair, Ph.D., professor of genetics, Harvard Medical School, Boston; Philippe Marambaud, Ph.D., investigator, Litwin-Zucker Center for Research in Alzheimer’s Disease and Memory Disorders, Feinstein Institute for Medical Research, Manhasset, N.Y.; May 1, 2012, Cell Metabolism
Last Updated: May 01, 2012
But when you turn over 90% of a story to a researcher who is a co-founder of and consultant for a company working on a drug and then quote the CEO of that company as well, it’s no surprise that you get a rosy projection.
If you care about this stuff, a far better piece of reporting was done by Nature News, “Row over resveratrol rumbles on.“
Just a little more than a year ago, when the company halted its resveratrol trial, the NY Times quoted a researcher at the National Institute on Aging:
“Resveratrol is a complex molecule in that it has many targets, and it behaves differently depending on the tissue and the metabolic status of the organism,” Dr. de Cabo said. That may make it too complex for a pharmaceutical company, which must prove to the Food and Drug Administration that a new drug works by a defined mechanism on a specific target. But resveratrol remains of great interest to researchers. “What is the actual use for humans still needs to be discovered,” he said.
We’re still a long way and many glasses of red wine away from answering these questions.
Not applicable. It’s understandable that costs were not discussed at this early animal-model stage of research.
If an entire consumer-targeted story is going to be based on research into mitochondrial function in mice, it could at least discuss how much such function improved. A little? A lot? In a few mice? All mice? How many mice? This story whiffed on giving any sense of the scope of the finding.
There was no discussion of potential harms, nor of the concern for potential harms in the leap from mice to humans, nor of how long and widely a substance would need to be tested in people before its safety could be projected.
We’ll give this a qualified satisfactory score, largely because of the ending quote from an independent expert, who said:
“A mouse model is not a human being, especially when you are genetically manipulating this animal model, you want to be very careful,” Marambaud said. “This field has been extremely controversial. We should be very careful about claiming the importance of resveratrol for medical purposes.”
But the headline – as often happens – belies any caveat in the body of the story, blaring how this finding “might help you live longer.”
Not applicable. Unless we’re talking about aging in mice.
Yes, the story turned to an independent expert at the end.
And, yes, it noted the conflicts of interest for the senior study author.
But it seemed to go out of its way to include a quote from the CEO of the drug company developing reseveratrol-like molecules – quoting him from an email he sent the journal that published the work. And it never explained WHY the company halted clinical trials of resveratrol in 2010. Before letting the CEO make new claims (“first definitive evidence”) about a new approach, it might have been helpful to review for readers why another approach was abandoned.
We think that’s only half a loaf, and give it an unsatisfactory score for that reason.
The story could have included even a line about other research in the prevention of cell aging.
The preliminary nature of these findings was clear in the body of the story (although not in the headline).
The story did mention some previous research on the issue:
“While previous studies have also suggested that resveratrol may have anti-aging properties, the precise mechanism of resveratrol has been controversial. Several studies, including work with yeast, worms and flies, have found that resveratrol acts on a class of seven genes known as sirtuins and, in human cells, SIRT1 in particular.”
There’s no evidence that the story relied solely on a news release.