TNF-alpha Makes Obese Rodents Put On Weight

Main Category: Obesity / Weight Loss / Fitness
Article Date: 17 Sep 2006 - 15:00 PDT

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Although we know that an individual becomes obese when the number of calories they consume is greater than the number burned by their body, much remains to be learned about what controls the number of calories the body burns. In a study appearing online on September 14, in advance of publication in the October print issue of the Journal of Clinical Investigation, researchers from the University of Milan, Italy, show that the soluble proinflammatory factor TNF-alpha decreases the amount of energy burned by a cell and increases the amount of weight gained by obese rodents.

Enzo Nisoli and colleagues showed that the number and energy burning function of mitochondria, the compartments in a cell where calories are burned to provide the cell with energy, in muscle cells and fat cells was decreased in three different rodent models of obesity. If the rodents lacked one of the receptors for TNF-alpha, the number and energy burning function of the mitochondria in the muscle and fat cells increased and, most importantly, the animals gained less weight. Conversely, the number and energy burning function of mitochondria in muscle and fat cells decreased after in vitro treatment with TNF-alpha. Because obesity is associated with chronic inflammation, this study provides insight into a molecular pathway that might sustain obesity.

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JCI table of contents: September 14, 2006

TITLE: TNF-alpha downregulates eNOS expression and mitochondrial biogenesis in fat and muscle of obese rodents

AUTHOR CONTACT:
Enzo Nisoli University of Milan, Milan, Italy.

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Contact: Karen Honey
Journal of Clinical Investigation

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