New Developments in Aging Research
Each day around the world 150,000 people die; two-thirds from age-related diseases like cancer and heart disease. Many of these conditions lead to lengthy hospital stays and costly medical treatments. An aging world population is driving some countries to fund biological research aimed at preventing the development of life-shortening diseases. Recently, scientists have discovered that removing old, harmful cells delays the onset of age-related conditions in laboratory animals. The latest developments in aging research and what they could mean for human health.
assistant professor of integrative biology and physiology at UCLA
professor, biochemistry/molecular biology, The Mayo Clinic
director, division of aging biology, National Institute on Aging at NIH
By age 65, most people will be diagnosed with two age-related diseases. Scientists at The Mayo Clinic recently found that removing old cells in mice prevented them from developing cataracts and muscle loss. At UCLA, researchers activated a gene in the stomach of a fruit fly that extended its life by 50 percent. But can these and other methods really prevent the onset of age-related illnesses and extend life?
Eventually, Cells Stop Dividing
"Senescence" is the term describing what happens when a cell loses its ability to divide. The phenomenon was discovered about 50 years ago, but until very recently, scientists couldn't directly connect it to the aging process. Now, researchers have found that once a cell experiences senescence, it can begin to secrete harmful substances, releasing them in to the body. Dr. Jan Van Deursen of the Mayo Clinic said that in mice, senescent cells have been definitively linked to a loss of muscle mass and functional fat - two hallmarks of the onset of many age-related illnesses.
Delaying the Onset of Disease
Van Deursen and his colleagues found out that by removing senescent cells from mice, they were actually able to delay the onset of diseases in their tissues. The researchers also found no overt negative side effects from the removal of the cells. But Van Deursen is careful to point out that his research is not a fountain of youth-like solution. "I would like to stress that we did not see a reversal of aging," he said. "It's not like we turned an old mouse in to a young mouse."
Genes With the Keys to Lifespan
David Walker, assistant professor of integrative biology and physiology at UCLA, is part of a team that has identified a gene in fruit flies that seems to control life span. When the gene's activity is boosted, fruit flies can live up to 50 percent longer. A normal fruit fly lifespan is about two months. Walker's team has figured out that the intestine, and the function of the digestive system, seem to be very important in aging. "The intestine is a vital organ for nutrient uptake...but it's also a very important barrier that protects us from pathogens and toxins in the environment," Walker said.
The Benefits of Calorie Restriction
Both the role of mitochondria and calorie restriction were the inspiration behind Walker's study. It's known that mitochondria decay is a function of age, and also that dietary restriction can extend lifespan. Although scientists don't yet know the exact mechanism, dietary restriction is actually shown to boost mitochondrial activity. The gene that Walker and his team identified in fruit flies performs the exact same function.
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