Massett Studying how Genes Affect Exercise Response

Written by: CEHD Communications Staff
Post date: January 10, 2011

  Courtesy The Eagle

A Texas A&M exercise physiologist is trying to identify genes that influence how people respond to exercise. Mike Massett, an assistant professor of exercise physiology, says the work being performed by him and his research team could help identify ways to help people who suffer from diseases related to a lack of physical fitness, such as diabetes, heart disease or cancer.

Many people believe one type of fitness program, workout or routine works for everyone, he said. But that's just not the case.

"If someone has a version of a gene that is not up to par, and if we know where to find that gene, we might be able to design therapeutic agents to turn that gene on, off or up a little," Massett says. "We might be able to modify the gene using a therapeutic agent, such as a drug or medication, or by changes in diet and exercise."

Massett brought a five-year, $1.25 million National Heart, Lung, and Blood Institute research grant to A&M when he left the University of Rochester Medical Center in Rochester N.Y. in 2007. While working in New York, Massett said, his interest was piqued by working with genetically modified mice.

"When we started, we realized no one had ever looked at a non-genetically modified mouse," he said. Massett said he and his three graduate students and a research associate staff member trained inbred mice to run 60 minutes per day on a treadmill for four weeks, slowly building up the intensity as a human might do.

Massett said mice were used because they can reproduce in a matter of weeks and provide the large number of subjects needed for a genetic study. The mice are tested both before and after the training to track their responses. "Some of the mice we tested improved by only a little bit ... less than 10 percent.

Some mice we tested improved a lot, more than 50 percent," he said. "Just think about, say, you and your friends back when you were in high school or elementary school. Everyone did the same kind of training program ... but some people had a small response and some people have a big response, even though they did the same workout." Cardiorespiratory fitness is a good predictor of morbidity, mortality and chronic disease, he said. The more fit you are, the lower your risk for these types of diseases.

"We can compare two strains for any kind of phenotype, or physical characteristic -- weight, body fat composition-- their ability to exercise on a treadmill or their response to exercise. If there is any difference between the two strains, we know that some component of this is due to genetics. We can use these differences to identify the genes that are responsible for that difference," he said.

Massett said this discovery could lead toward a more targeted solution for people with, for example, a family history of heart disease, whether it be another type of workout or medication. "It's just a matter of 'Can we target a certain cellular pathway that may help you respond to exercise?'" he said.

Right now, he said, the main goal is to identify those genes. The researchers have found a few key places to look, he said. These genes then can be explored in humans to see if they are related to training response, he said.

"The mouse is very genetically like the human, so a lot of the genetics should transfer fairly well," he said.