Dr. Matthew Rodeheffer can really chew the fat.
A pioneer in the exploration of how fat cells form and lead to obesity, Rodeheffer expresses a voluble intellectual enthusiasm about these dynamic cells that can expand and contract and change their mass.
But he doesn’t chat idly. Lives are on the line.
“What I really want to understand is what is causing the obesity epidemic,” Rodeheffer said. “I’m positive that there is more to it than people eating too much and not exercising enough.”
More than one third of adults in the country are considered obese, meaning they are excessively overweight for their height. Combining obese adults with less severely overweight adults, the prevalence reaches 69 percent of the population.
And while obesity can be found in about equal numbers of women and men, obese women suffer up to eight times greater rates of obesity-related conditions, such as heart disease, stroke, and type 2 diabetes.
Rodeheffer, an Assistant Professor of Comparative Medicine and of Molecular, Cellular, and Developmental Biology at Yale School of Medicine, seeks to understand differences in how fat affects health in different subgroups. His lab focuses on the role of white adipose tissue (WAT), a collection of fat cells that store energy and — when created in excess — make the body obese.
He notes that the body tries to find a set point of fat mass. Fat cells are created as someone gains weight. But even when people lose fat, they don’t lose fat cells. The cells just shrink in size, which might be why people have such difficulty maintaining weight loss.
Current evidence suggests that WAT that collects around the abdomen, the traditional “beer belly” known as visceral WAT, contributes more to obesity-related disease than WAT that collects under the skin, known as subcutaneous WAT.
Obese men more often exhibit visceral WAT than women, who tend to collect WAT under the skin all over their bodies. But the association of fat distribution and disease has only been studied in men or male animals. Until now.
Starting with a Women’s Health Research at Yale seed grant in 2011, Rodeheffer has gathered data using mice on a high-fat diet to support his hypothesis that excessive accumulation of all WAT in females — and not just in the abdomen — contributes to disease.
At the end of the pilot project, what we really knew is that females have a different pattern of fat cell formation.
Matthew Rodeheffer, PhD
“At the end of the pilot project, what we really knew is that females have a different pattern of fat cell formation,” Rodeheffer said. “But if the mechanism is different, is the fat cell itself different? Does it have a different function? Is the link to disease direct or indirect? We don’t yet know.”
Like so many WHRY-funded researchers before him, Rodeheffer has leveraged data from the seed grant to earn far greater funding from the National Institutes of Health toward the goal of answering these and many other questions.
“We’ve done more work showing that fat cell formation is via a molecular pathway we don’t understand — different than development of normal fat mass,” Rodeheffer said.
In addition, the team has made preliminary observations that suggest fat cells form faster in female mice than in males.
Future avenues of research involve the roles of hormones and exercise in the onset of diet-related obesity.
And with more knowledge on how women become obese, Rodeheffer hopes to offer better ways to understand and treat this epidemic.
“The difference is drastic enough between males and females, that we can use it as a tool for new inquiries,” he said. “There is so much more to learn.”
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