An East Carolina University exercise scientist will spend the next five years learning how children metabolize fat.
Through a five-year, $1.5 million grant from the National Institutes of Health, ECU professor Bob Hickner hopes to learn how nitric oxide affects fat breakdown, known as lipolysis, in both lean and overweight children, and the role exercise plays in the process.
“Overweight individuals tend to have more nitric oxide in their fat tissue than lean individuals,” Hickner said. “Overweight individuals therefore become overweight, or remain overweight, in part because too much nitric oxide slows lipolysis. We’re hoping to alter that with the physical activity program.”
A sampling technique called microdialysis will enable Hickner to record hourly each child’s metabolic processes. A thin tube that works like a capillary absorbs and stores small amounts of substances released from the fat cells. Glycerol is one such molecule that is released from fat cells when fat stores are mobilized. The tube is inserted into the fat just under the skin in the abdominal area. The molecules collected from this process will provide valuable data about how participants’ fat cells break down and release fat around the clock, Hickner said, not just during controlled, physical activities in a fitness lab.
“There may be differences in lipolysis between children during the time they spend in their everyday activities outside of the laboratory that may or may not be evident in the controlled laboratory setting,” he said. “The children’s activity and food intake are also monitored throughout the day during the microdialysis monitoring. Maybe they’ll eat less, or more, or perhaps be more, or less active, during the day outside of the Lab.”
Hickner is looking for 160 Caucasian and African American children, ages eight to 11, who are willing to participate in a 16-week study. Study participants will visit ECU’s Human Performance Lab to engage in daily activities such as jumping rope, interactive video games, and other activities planned and supervised by Exercise and Sport Science faculty and staff Mike McCammon and Patricia Brophy.
Hickner said he hopes the study will enable him to understand the role nitric oxide plays in the breakdown of fat in lean compared to overweight individuals. To gauge this, a nitric oxide synthase inhibitor will be sent through the microdialysis probe into the fat tissue, which will enable Hickner to measure lipolysis in the presence and absence of nitric oxide.
A second NIH grant will help Hickner to isolate the specific step in the lipolysis pathway affected by nitric oxide and another molecule, adenosine. To understand this aspect of the study, Hickner and post-doctoral fellow Myung Dong Choi, along with Hisham Barakat (Department of Internal Medicine in the Brody School of Medicine) and Kenneth MacDonald (formerly Department of Surgery, BSOM) are working with candidates for gastric bypass surgery at the Brody School of Medicine. The three-year, $215,000 grant will enable them to further study the role of nitric oxide in lipolysis using microdialysis.
Studying lipolysis in children using microdialysis has never been done elsewhere, Hickner said, but it could play a critical role in finding links to how overweight children become obese adults.
In addition to the lipolysis studies, other researchers will study blood samples from these study groups to look for markers of heart disease, such as high cholesterol, while Recreation and Leisure Studies professors Tom Raedeke and Janet Funderburk will interview the children to gauge their mental and psychological well-being. Other investigators in the Department of Exercise and Sport Science will study physical activity patterns (Mathew Mahar and Katrina DuBose) and issues related to protein metabolism (Courtney Gaine and doctoral student Mike Ormsbee) in these children. Kimberly Heidal and Brenda Malinauskas of the Department of Nutrition will study dietary issues. All studies will be conducted with the medical support of Dr. Joseph Garry and Dr. John Olsson from the Brody School of Medicine and the statistical support of Don Holbert of Allied Health Sciences.
“There is a real team effort in these studies that makes the most of the NIH funding,” says Hickner.
Those interested in participating may contact Patty Brophy at 737-4681.