A common virus that causes cold and eye infections may also lead to obesity, according to research presented at the national meeting of the American Chemical Society.
Infection with human adenovirus-36 (Ad-36) seems to direct adult stem cells from fat tissue to turn into fat cells, researchers have found in lab experiments. Stem cells not exposed to the virus, in contrast, were unchanged.
More importantly, the researchers have identified the specific gene in the virus that appears to be involved in this obesity-promoting effect: E4Orfl.
The field of research investigating the role of viruses in obesity -- dubbed "infectobesity" -- is still relatively new and experimental. Researchers don't believe that infection with one of these pathogens is the sole cause of obesity but they say some obesity cases may involve viral infections.
"I think what this virus story really tells us is that obesity is a much more complicated issue than we think. It's very easy to blame the obesity epidemic on fast food and people watching too much television," said Dr. Arya Sharma, a McMaster University professor who is also the Canada research chair in cardiovascular obesity research and management.
"This study provides evidence that it's much more complicated than that," he told 愛污传媒.
If the findings are proven true, it raises the possibility that a vaccine or antiviral medication could one day help fight some forms of obesity.
Study presenter Dr. Magdalena Pasarica, of the Pennington Biomedical Research Center at Louisiana State University in Baton Rouge, notes that researchers don't believe that everyone who has been infected with Ad-36, which is widespread in nature, will develop obesity.
"We would ultimately like to identify the underlying factors that predispose some obese people to develop this virus and eventually find a way to treat it," she said.
Pasarica was part of a research group that demonstrated that the Ad-36 virus was capable of causing animals infected with the virus to accumulate fat. Led by Dr. Nikhil Dhurandhar, an associate professor at Louisiana State University, the group also conducted a noted epidemiologic study that found that 30 per cent of obese people were infected with the Ad-36 virus in comparison to just 11 per cent of lean individuals.
But evidence that the virus could actually cause fat levels to increase in human cells was lacking until now, Pasarica says.
In the current study, Pasarica and her associates 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. After about a week of growth in tissue culture, most of the virus-infected adult stem cells developed into fat cells.
Pasarica and her associates are now in the process of trying to identify the factors that predispose some people with Ad-36 to develop obesity while others do not.
And Pasarica does not rule out the possibility that other human viruses may also contribute to obesity.
With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip
