Brown Fat Transplant May Aid in Weight Loss and Diabetes Management
A study conducted by ADA-funded researchers at the Joslin Diabetes Center suggests that brown fat transplants could help combat obesity and lower the risk of developing type 2 diabetes. In the January 2013 issue of The Journal of Clinical Investigation, Laurie J. Goodyear, PhD, and postdoctoral fellow Roeland J.W. Middelbeek, MD, show that increasing brown fat via transplantation dramatically promotes weight loss and improves blood-glucose control in mice – results that they hope may translate to humans.
There are at least two types of adipose (fat) tissue. White adipose tissue is the more common type that lies below the skin, stores excess fat in the body, and expands with weight gain. Brown adipose tissue, on the other hand, is derived from muscle and is highly thermogenic. In other words, it burns energy to produce heat and maintain body temperature in warm-blooded organisms. Unlike white adipose tissue, the quantity of brown fat in the body is inversely proportional to body mass index (BMI), meaning that lean people tend to store more of this type of fat than people that are overweight, leading to the characterization of brown fat as “good” fat.
While the thermogenic effects of brown fat are well known, scientists have long debated the effects of brown fat on glucose metabolism. Dr. Goodyear and Dr. Middelbeek’s study addresses this question and suggests that brown adipose tissue serves a much broader function in regulating metabolism and body composition than previously thought.
To determine whether brown fat functioned as a metabolic regulator, Dr. Goodyear and Dr. Middelbeek transplanted brown fat into normal weight mice and observed how it affected weight gain and glucose homeostasis over time. By eight to twelve weeks after the procedure, the mice receiving the brown fat transplant had significantly lower body weight, reduced white fat mass, better insulin sensitivity, and improved glucose metabolism overall, compared to mice that did not receive brown fat transplants. The researchers also found that when they increased the amount of brown fat that was transplanted, the metabolic benefits were amplified.
The detrimental effects of consuming a high-fat diet have been clearly established in mice. Strikingly, transplantation of brown fat into overweight mice that had been fed a high-fat diet reversed many of the problems associated with such eating habits; it slowed weight gain, reversed insulin-resistance, and improved the lipid profiles of the animals.
With the worldwide obesity epidemic on the rise, Dr. Goodyear and Dr. Middelbeek hope to quickly translate their findings into humans and develop novel treatment strategies for obesity and metabolic disorders like insulin resistance, metabolic syndrome, and type 2 diabetes.
“We hope that manipulating brown adipose tissue can help people with type 1 and type 2 diabetes,” said Dr. Goodyear.
(Kristin I. Stanford, Roeland J.W. Middelbeek, Kristy L. Townsend, Ding An, Eva B. Nygaard, Kristen M. Hitchcox, Kathleen R. Markan, Kazuhiro Nakano, Michael F. Hirshman, Yu-Hua Tseng, Laurie J. Goodyear. Brown adipose tissue regulates glucose homeostasis and insulin sensitivity. Journal of Clinical Investigation, 2012; DOI: 10.1172/JCI62308)