Scientists find molecular trigger that helps prevent aging and disease

Scientists find molecular trigger that helps prevent aging and disease

ScienceDaily (Nov. 23, 2009) — Researchers at Mount Sinai School of Medicine set out to address a question that has been challenging scientists for years: How does dietary restriction produce protective effects against aging and disease? And the reverse: how does overconsumption accelerate age-related disease?...How the diet is restricted -- whether fats, proteins or carbohydrates are cut -- does not appear to matter. "It may not be about counting calories or cutting out specific nutrients," said Dr. Mobbs, "but how a reduction in dietary intake impacts the glucose metabolism, which contributes to oxidative stress." Meanwhile, a high calorie diet may accelerate age-related disease by promoting oxidative stress... Dietary restriction induces a transcription factor called CREB-binding protein (CBP), which controls the activity of genes that regulate cellular function. By developing drugs that mimic the protective effects of CBP -- those usually caused by dietary restriction -- scientists may be able to extend lifespan and reduce vulnerability to age-related illnesses...."We discovered that CBP predicts lifespan and accounts for 80 percent of lifespan variation in mammals," said Dr. Mobbs. "Finding the right balance is key; only a 10 percent restriction will produce a small increase in lifespan, whereas an 80 percent restriction will lead to a shorter life due to starvation."...The team found an optimal dietary restriction, estimated to be equivalent to a 30 percent caloric reduction in mammals, increased lifespan over 50 percent while slowing the development of an age-related pathology similar to Alzheimer's disease..."We showed that dietary restriction activates CBP in a roundworm model, and when we blocked this activation, we blocked all the protective effects of dietary restriction," said Dr. Mobbs. "It was the result of blocking CBP activation, which inhibited all the protective effects of dietary restriction, that confirmed to us that CBP plays a key role in mediating the protective effects of dietary restriction on lifespan and age-related disease."...Researchers examined mice and found that diabetes reduces activation of CBP, leading Dr. Mobbs to conclude that a high-calorie diet that leads to diabetes would have the opposite effect of dietary restriction and would accelerate aging...Dr. Mobbs hypothesizes that dietary restriction induces CBP by blocking glucose metabolism, which produces oxidative stress, a cellular process that leads to tissue damage and also promotes cancer cell growth. Interestingly, dietary restriction triggers CBP for as long as the restriction is maintained, suggesting that the protective effects may wear off if higher dietary intake resumes. CBP responds to changes in glucose within hours, indicating genetic communications respond quickly to fluctuations in dietary intake..."

Spices halt growth of breast stem cells, study finds

Spices halt growth of breast stem cells, study finds: "Spices Halt Growth of Breast Stem Cells, Study Finds

ScienceDaily (Dec. 8, 2009) — A new study finds that compounds derived from the spices turmeric and pepper could help prevent breast cancer by limiting the growth of stem cells, the small number of cells that fuel a tumor's growth...when the dietary compounds curcumin, which is derived from the Indian spice turmeric, and piperine, derived from black peppers, were applied to breast cells in culture, they decreased the number of stem cells while having no effect on normal differentiated cells..."

Link between sirtuins and life extension strengthened

Link between sirtuins and life extension strengthened

ScienceDaily (Dec. 15, 2009) — A new paper from MIT biology professor Leonard Guarente strengthens the link between longevity proteins called sirtuins and the lifespan-extending effects of calorie restriction...sirtuins bring about the effects of calorie restriction on a brain system, known as the somatotropic signaling axis, that controls growth and influences lifespan length..."This puts SIRT1 at a nexus connecting the effects of diet and the somatropic signaling axis," says Guarente. "This is a major shot across the bow that says sirtuins really are involved in fundamental aspects of calorie restriction."...The researchers genetically engineered mice whose ability to produce the major mammalian sirtuin SIRT1 in the brain was greatly reduced. Those mice and normal mice were placed on a calorie-restricted diet. The normal mice showed much lower levels of circulating growth hormones, demonstrating that their somatotropic signaling system was impaired, but calorie restriction had no effect on hormone levels of mice that could not produce SIRT1..."

Mutant genes 'key to long life'

BBC NEWS | Health | Mutant genes 'key to long life': "There is a clear link between living to 100 and inheriting a hyperactive version of an enzyme that prevents cells from ageing, researchers say. Scientists from the Albert Einstein College of Medicine in the US say centenarian Ashkenazi Jews have this mutant gene. They found that 86 very old people and their children had higher levels of telomerase which protects the DNA. They say it may be possible to produce drugs that stimulate the enzyme...The team at Einstein found that the centenarians and their offspring had higher levels of telomerase and significantly longer telomeres than the unrelated people in the control group and that the trait was strongly heritable... The scientists had previously shown that individuals in Ashkenazi families with exceptional longevity have generally been spared major age-related diseases, like heart disease and diabetes. The centenarians in this study had a lower average body mass index than the controls and higher levels of good (HDL) cholesterol. Yousin Suh, associate professor of medicine and genetics at Einstein and a lead author on the paper, said: "Our findings suggest that telomere length and variants of telomerase genes combine to help people live very long lives, perhaps by protecting them from the diseases of old age... "

BBC News - People who look young for their age 'live longer'

BBC News - People who look young for their age 'live longer': "People blessed with youthful faces are more likely to live to a ripe old age than those who look more than their years, work shows...Danish scientists say appearance alone can predict survival, after they studied 387 pairs of twins...Key pieces of DNA called telomeres, which indicate the ability of cells to replicate, are also linked to how young a person looks...A telomere of shorter length is thought to signify faster ageing and has been linked with a number of diseases. In the study, the people who looked younger had longer telomeres. "

Balancing protein intake, not cutting calories, may be key to long life

Balancing protein intake, not cutting calories, may be key to long life: "ScienceDaily (Dec. 6, 2009) — Getting the correct balance of proteins in our diet may be more important for healthy ageing than reducing calories, new research funded by the Wellcome Trust and Research into Ageing suggests...In fact, when the researchers studied the effect further, they found that levels of a particular amino acid known as methionine were crucial to maximising lifespan without decreasing fertility. Adding methionine to a low calorie diet boosted fertility without reducing lifespan; likewise, reducing methionine content in a high calorie diet prolonged lifespan. Previous studies have also shown that reducing the intake of methionine in rodents can help extend lifespan...Amino acids are the building blocks of life as they form the basis of proteins. Methionine is one of the most important amino acids at it is essential to the formation of all proteins. Whilst proteins are formed naturally in the body, we also consume proteins from many different food types, including meat and dairy products, soy-derived food such as tofu, and pulses. The relative abundance of methionine differs depending on the food type in question; it occurs in naturally high levels in foods such as sesame seeds, Brazil nuts, wheat germ, fish and meats..."It's not as simple as saying 'eat less nuts' or 'eat more nuts' to live longer -- it's about getting the protein balance right, a factor that might be particularly important for high protein diets, such as the Atkins diet or body builders' protein supplements."..."

Calorie intake linked to cell lifespan, cancer development

Calorie intake linked to cell lifespan, cancer development: "ScienceDaily (Dec. 18, 2009) — Researchers from the University of Alabama at Birmingham (UAB) have discovered that restricting consumption of glucose, the most common dietary sugar, can extend the life of healthy human-lung cells and speed the death of precancerous human-lung cells, reducing cancer's spread and growth rate..."Our research indicates that calorie reduction extends the lifespan of healthy human cells and aids the body's natural ability to kill off cancer-forming cells."...

In particular, the researchers found that two key genes were affected in the cellular response to decreased glucose consumption. The first gene, telomerase, encodes an important enzyme that allows cells to divide indefinitely. The second gene, p16, encodes a well known anti-cancer protein."Opposite effects were found for these genes in healthy cells versus precancerous cells. The healthy cells saw their telomerase rise and p16 decrease, which would explain the boost in healthy cell growth," Tollefsbol said. "The gene reactions flipped in the precancerous cells with telomerase decreasing and the anti-cancer protein p16 increasing, which would explain why these cancer-forming cells died off in large numbers.""

Not So Sweet: Over-consumption Of Sugar Linked To Aging

Not So Sweet: Over-consumption Of Sugar Linked To Aging: ScienceDaily (Mar. 9, 2009)"We know that lifespan can be extended in animals by restricting calories such as sugar intake. Now, according to a study published in the journal PLoS Genetics, Universite de Montreal scientists have discovered that it's not sugar itself that is important in this process but the ability of cells to sense its presence...if they removed the gene for a glucose sensor from yeast cells, they lived just as long as those living on a glucose-restricted diet. In short, the fate of these cells doesn't depend on what they eat but what they think they're eating...The scientists found that cells unable to consume glucose as energy source are still sensitive to the pro-aging effects of glucose. Conversely, obliterating the sensor that measures the levels of glucose significantly increased lifespan..."