Biosingularity

Calorie restriction may prevent Alzheimer’s through promotion of longevity program in the brain

Posted on: June 14, 2006

For the first time researchers show how restricting caloric intake triggers activity in the brain associated with longevity.

A recent study directed by Mount Sinai School of Medicine suggests that experimental dietary regimens might calm or even reverse symptoms of Alzheimer’s Disease (AD). The study, which appears in the July 2006 issue of the Journal of Biological Chemistry, is the first to show that restricting caloric intake, specifically carbohydrates, may prevent AD by triggering activity in the brain associated with longevity.

“Both clinical and epidemiological evidence suggests that modification of lifestyle factors such as nutrition may prove crucial to Alzheimer’s Disease management,” says Giulio Maria Pasinetti, M.D., Ph.D., Professor of Psychiatry and Neuroscience, Director of the Neuroinflammation Research Center at Mount Sinai School of Medicine and lead author of the study. “This research, however, is the first to show a connection between nutrition and Alzheimer’s Disease neuropathy by defining mechanistic pathways in the brain and scrutinizing biochemical functions. We hope these findings further unlock the mystery of Alzheimer’s and bring hope to the millions of Americans suffering from this disease.”

Alzheimer’s Disease is a rapidly growing public health concern with potentially devastating effects. An estimated 4.5 million Americans have Alzheimer’s Disease and the number of Americans with Alzheimer’s has more than doubled since 1980. Presently, there are no known cures or effective preventive strategies. While genetic factors are relevant in early-onset cases, they appear to play less of a role in late-onset-sporadic AD cases, the most common form of AD.

Longevity Program in the Brain
People with AD exhibit elevated levels of beta-amyloid peptides that cause plaque buildup in the brain (the main characteristic of AD). Beta-amyloid peptides activate SIRT1, a member of a broad family of proteins known as sirtuins which influence a variety of functions including metabolism and aging.

Dr. Pasinetti and colleagues used an experimental mouse model to demonstrate that beta-amyloid peptides in the brain can be reduced by subjecting the mice to dietary caloric restriction, primarily based on low carbohydrate food. Conversely, a high caloric intake based on saturated fat was shown to increase levels of beta-amyloid peptides.

This study is the first to suggest that caloric restriction through promotion of SIRT1 (a molecule associated with brain longevity) may initiate a cascade of events like the activation of alpha-secretase which can prevent AD amyloid neuropathology. Since alpha-secretase is known also to inhibit the generation of beta-amyloid peptides in the AD affected brain, the study demonstrates a mechanism by which dietary caloric restriction might benefit AD. Most remarkably, the study finds that a high caloric intake based on saturated fat promotes AD type beta-amyloidosis, while caloric restriction based on reduced carbohydrate intake is able to prevent it.

Implications
Among lifestyle factors influencing AD, recent studies strongly support the evidence that caloric intake may play a role in the relative risk for AD clinical dementia. Most importantly, as mechanistic pathways are defined and their biochemical functions scrutinized, the evidence supporting a direct link between nutrition and AD neuropathology continues to grow.

Source: The Mount Sinai Hospital / Mount Sinai School of Medicine  

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6 Responses to "Calorie restriction may prevent Alzheimer’s through promotion of longevity program in the brain"

I wonder if the effect of resveratrol on sirt1 would have a similar effect as CR vis a vis Alzheimer’s? The mechanism is plausible, as far as it goes.

That is an interesting idea Al Fin. Indeed the mechanism is plausible. Although I think it is not entirely clear whether resveratrol effects on humans is all through sirt1.

If I remember correctly, Kaeberlein had an article at the beginning of 2005, in which he claimed that Reseveratrol doesn’t work through Sirt1. He claimed that previous findings were artifacts.

Lucy –

are you referrring to this paper?:
J Biol Chem. 2005 Apr 29;280(17):17038-45. Epub 2005 Jan 31. Related Articles, Links

Substrate-specific activation of sirtuins by resveratrol.

Kaeberlein M, McDonagh T, Heltweg B, Hixon J, Westman EA, Caldwell SD, Napper A, Curtis R, DiStefano PS, Fields S, Bedalov A, Kennedy BK.

Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.

Resveratrol, a small molecule found in red wine, is reported to slow aging in simple eukaryotes and has been suggested as a potential calorie restriction mimetic. Resveratrol has also been reported to act as a sirtuin activator, and this property has been proposed to account for its anti-aging effects. We show here that resveratrol is a substrate-specific activator of yeast Sir2 and human SirT1. In particular, we observed that, in vitro, resveratrol enhances binding and deacetylation of peptide substrates that contain Fluor de Lys, a non-physiological fluorescent moiety, but has no effect on binding and deacetylation of acetylated peptides lacking the fluorophore. Consistent with these biochemical data we found that in three different yeast strain backgrounds, resveratrol has no detectable effect on Sir2 activity in vivo, as measured by rDNA recombination, transcriptional silencing near telomeres, and life span. In light of these findings, the mechanism accounting for putative longevity effects of resveratrol should be reexamined.

Exactly:) Btw, what is your opinion, if you have one, about Kaeberlein’s attempt to place Sir2 out of the CR pathway?

[…] compound, and its expression has been linked to many other protective mechanisms, such as the production of an Alzheimer’s disease-preventing […]

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