THE OBESITY FACTOR
Darlene Berryman has the skinny on fat. A scientist, nutrition expert and aerobics instructor, Berryman understands flab on a molecular and a real-world level. And with health experts declaring that almost two-thirds of adult Americans are overweight, it’s good to have this Ohio University assistant professor of human and consumer sciences on the case.
“It’s one of our biggest health problems,” she says, “with no end in sight.”
Though doctors argue that it’s simple to understand how we get fat — gobbling too many French fries, spending evenings with TiVo instead of the treadmill — most Americans would counter that it’s hard to figure out how to lose the extra weight. It turns out that fat, or “adipose tissue,” actually is a more complex part of the human body than first thought, Berryman notes. That’s why she’s found it such an intriguing subject of scientific study since her graduate school days at Cornell University.
“It’s an endocrine organ,” she says of adipose tissue. “It communicates with other parts of your body and says ‘You don’t have enough fat; you need to eat more.’”
Berryman has studied fat at the cellular level and has taught Ohio University undergraduates as well as pharmacists and dietitians around the country about the dangers of obesity. Her latest project brings her back to the laboratory to explore a fat phenomenon in subjects smaller and furrier than the average American couch potato: lab mice.
Scientists at Ohio University’s Edison Biotechnology Institute have developed transgenic mice that have either an abundance or lack of growth hormone, a substance produced by the pituitary gland that promotes normal body growth and development. Senior scientist John Kopchick, Goll Ohio professor of molecular biology with EBI and the College of Osteopathic Medicine, and his colleagues discovered an antagonist in the late 1980s that could block the action of growth hormone. The science has since been used as the basis for a drug to treat acromegaly, a medical condition that causes abnormal growth of organs and bones in about 40,000 adults worldwide.
Kopchick’s laboratory now studies how growth hormone relates to two major American health problems — obesity and diabetes — and has observed a curious phenomenon in the lab mice there. Those bred to express little growth hormone are small and fat, while those bred to express a lot of growth hormone are big and lean. It’s the same principle that attracts some athletes to the illegal use of growth hormone to enhance their physique and performance, Berryman notes.
But the Ohio University scientists have found one important caveat with the mice models: The large, slim ones also have diabetes, whereas their smaller, chubbier counterparts are surprisingly hale. The researchers point to lifespan as another key sign of their health. Normal mice live for about two years, but the growth hormone-enhanced mice die after one. The small mice, however, may survive for four years.
How might biology explain this? Supported by a three-year, $350,000 grant from the National Institutes of Health, Berryman hopes to find answers. She’ll be busy in the lab solving several questions: Does growth hormone change the protein responsible for controlling the movement of fat in and out of cells? Can growth hormone impact how much fat the body gains and where it’s distributed on the body? And if so, how exactly does growth hormone build fat — through more or bigger fat cells?
Her preliminary research suggests that growth hormone can affect the total amount of fat and where it’s deposited. The location is important, as scientists have learned in the past decade that not all fat is created equal, Berryman says. Fat around the midsection is more troublesome than fat right under the skin — such as the stuff that pads the hips — because it can produce different endocrine hormones and can expel more fatty acids into the blood, she explains.
Berryman expects her new examination of the science of fat to help her kick start her research career at Ohio University. She arrived in Athens in 1999 when her husband, Assistant Professor of Biomedical Sciences Mark Berryman, accepted a position with the College of Osteopathic Medicine. Though Darlene Berryman completed a graduate degree and postdoctoral work that focused on the basic biology of fat metabolism, she decided to become a registered dietitian so she could make a direct impact on human health and nutrition. When Berryman sought a way to unite her biology background with her nutrition know-how, Brooke Hallowell, associate dean for research in the College of Health and Human Services, pointed her toward the NIH funding opportunity. Berrymen later connected with Kopchick’s lab.
“She helps us a lot because she brings in a nutritional aspect that we don’t think about much but should,” says Kopchick, who will serve as a lead mentor on the project.
Berryman’s grant was awarded through an NIH program that supports up-and-coming researchers. In this case, a network of mentors and collaborators at Ohio, Yale, Rutgers and Ohio State universities will consult Berryman on aspects of the research she is less familiar with, such as working with lab animals and molecular biology tools and technologies that have changed since she last worked in that field in the 1990s.
“This grant will allow her to do what she wants to do — and she’s good at it, too,” says Karen Coschigano, an assistant professor of biomedical sciences who also will serve as a mentor on the project. Coschigano, who previously worked in Kopchick’s lab, helped Berryman brush up on lab skills and write the grant. She expects that the work could help other growth hormone researchers learn more about fat metabolism and could open the doors to additional NIH funding for Berryman in the future.
If so, Berryman may be part of a larger trend at Ohio University. In a quest to heighten its research reputation over the next decade, the university will focus on projects in biotechnology and health care and seek additional federal funding from agencies such as the NIH to address health problems that include diabetes, obesity and cancer. That’s especially relevant to southeast Ohio, where researchers in the university’s Appalachian Rural Health Institute have found people experience these and other diseases at a much higher rate than the national average. In a related line of research, Berryman has noted that children in Appalachia also show high rates of obesity. With her colleagues in ARHI, she hopes to explore the causes of this regional health phenomenon. And in both the childhood obesity and growth hormone projects, several undergraduate and graduate students will assist Berryman in solving these medical issues while gaining hands-on research experience.
In the battle of the bulge, Berryman also practices what she preaches. She became a certified aerobics instructor in 1990 as a way to stay in shape during the long upstate New York winters she spent at Cornell, and she has continued to lead aerobics classes on the Athens campus.
But while Berryman might sweat a few dozen people into healthier bodies each year, the research she’s embarking on in the lab could have wider implications: A greater understanding of the science behind one of our greatest public health woes.
-- This story originally appeared in the Spring 2005 issue of Ohio Today.