Submitted on January 2, 2008
Accepted on June 5, 2008
EXERCISE BUT NOT DIET-INDUCED WEIGHT LOSS DECREASES SKELETAL MUSCLE INFLAMMATORY GENE EXPRESSION IN FRAIL OBESE ELDERLY
Charles P Lambert1, Nicole R Wright2, Brian N Finck1, and Dennis Tan Villareal1*
1 Division of Geriatrics and Nutritional Sciences, Washington University School of Medicine, United States
2 Division of Geriatrics and Nutritional Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
* To whom correspondence should be addressed. E-mail: dvillare{at}im.wustl.edu.
Many obese elderly persons have impaired physical function associated with an increased chronic inflammatory response. We evaluated 12 weeks of exercise (aerobic and resistance) or 12 weeks of weight loss (~7% reduction) on skeletal muscle mRNAs for toll-like receptor-4, (TLR-4), mechanogrowth factor (MGF), tumor necrosis factor-
(TNF-), and interleukin-6 (IL-6) in 16 obese (BMI: 38±2 kg/m2) older (69±1 yrs) physically frail individuals. m. vastus lateralis biopsies were obtained at 0 and 12 weeks and analyzed by real time RT-PCR. Body composition was assessed by dual x-ray absorptiometry. Body weight decreased (-7.5 ±1.2 kg, p=0.001) in the weight loss group, but not in the exercise group (-0.3±0.8 kg, p=0.74). Fat free mass (FFM) decreased (-2.9±0.6 kg, p=0.010) in the weight loss group and increased (1.6±0.6 kg, p=0.03) in the exercise group. Exercise resulted in a 37% decrease in TLR-4 mRNA (p<0.05) while weight loss had no significant effect. Additionally, exercise led to a significant (50%) decrease in IL-6 and TNF- mRNA (p<0.05) while weight loss had no effect. Exercise increased MGF mRNA (~2 fold, p<0.05) but weight loss had no effect. In conclusion, exercise but not weight loss had a beneficial effect on markers of muscle inflammation and anabolism in frail obese elderly individuals.
