Adenovirus-36: a contributing factor in Obesity

Scientists have presented a new study showing infection with the adenovirus-36 (Ad-36) virus, long recognized as a cause of respiratory and eye infections in humans, may be a contributing factor.

Their laboratory experiments they showed that infection with Ad-36 transforms adult stem cells obtained from fat tissue into fat cells. Stem cells not exposed to the virus, in contrast, were unchanged.

They obtained adult stem cells from fatty tissue from a broad cross-section of patients who had undergone liposuction. Half of the stem cells were exposed to Ad-36 and the other half were not exposed to the virus.

After about a week of growth in tissue culture, most of the virus-infected adult stem cells developed into fat cells, whereas the non-infected stem cells did not, the researchers say.

The research group  identified a gene in the Ad-36 virus that appears to be involved in causing fat accumulation observed in infected animals. That gene, called E4Orfl, is now emerging as a promising target for future human therapies, such as vaccines and anti-viral medicines, aimed at preventing or inhibiting the obesity virus.

The exact mechanism by which the virus might cause obesity in people is currently unknown, says Magdalena Pasarica, M.D., Ph.D., of the Pennington Biomedical Research Center, a campus of the Louisiana State University system, who does not rule out the possibility that other human viruses may also contribute to obesity.


Researchers also do not know how long the virus remains in the body of obese individuals nor how long its fat-enhancing effect lasts once the virus is gone. However, Pasarica notes a recent study demonstrated that animals that developed the virus remained obese up to six months after their infection was gone. More studies are needed, especially in humans, she adds.

Pasarica was part of the original research group which demonstrated that the Ad-36 virus was capable of causing animals infected with the virus to accumulate fat. Led by Nikhil Dhurandhar, Ph.D., now an associate professor at Pennington Biomedical Research Center, the group also conducted a noted epidemiologic study — the first to associate a virus with human obesity — showing 30 percent of obese people were infected with the Ad-36 virus in comparison to 11 percent of lean individuals. But evidence that the virus could actually cause fat levels to increase in human cells was lacking until now, Pasarica says.


Exactly how the virus might cause obesity remains unclear. The researchers are also unsure of the length of time the virus might remain in infected patients and how long its effects continue even if it is eradicated.


Other major contributing factors of Obesity are bad lifestyle  -- overeating, drinking too many sodas, not getting enough exercise. In general, to become obese there has to be some sort of mismatch between energy intake and energy expenditure. Again, that gets back to the same old advice: Eat healthfully and exercise regularly to keep weight under control.


Tips for Creating Healthy Eating Habits and Active Lifestyles

  • Don't eat if you're not hungry.

  • Never use food as a reward—offering dessert, as a reward for eating the rest of a meal, is a common mistake.

  • Limit fast food and order small.

  • Eat slowly. It takes several minutes for the stomach to feel "full."

  • Limit TV time, computer time and video game time.

  • Keep selections of fruit and vegetable snacks handy.

  • Avoid preprocessed foods when shopping.

  • Exercise daily- The recommended exercise level for obesity prevention and better health is thirty minutes of light to moderate exercise five times a week.

  • Encourage active games—run and play together. 

  • Keep track of everything you eat for a month, noting times, locations and amounts. List everything you eat and drink, including snacks and trips to the water cooler. At the end of the month, sit down with the food diary and look for trends in your eating pattern.


Source: American Chemical Society, BIOHW 003, presented at 10:15 a.m., Monday, Aug. 20, at the Boston Convention & Exhibition Center, Room 203, during the symposium, "Genomics of Obesity."

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