Mitochondrial dysfunction in obesity

PURPOSE OF REVIEW: The review highlights recent findings regarding the functions of mitochondria in adipocytes, providing an understanding of their central roles in regulating substrate metabolism, energy expenditure, disposal of reactive oxygen species (ROS), and in the pathophysiology of obesity and insulin resistance, as well as roles in the mechanisms that affect adipogenesis and mature adipocyte function. RECENT FINDINGS: Nutrient excess leads to mitochondrial dysfunction, which in turn leads to obesity-related pathologies, in part due to the harmful effects of ROS. The recent recognition of 'ectopic' brown adipose in humans suggests that this tissue may play an underappreciated role in the control of energy expenditure. Transcription factors, PGC-1alpha and PRDM16, which regulate brown adipogenesis, and members of the TGF-beta superfamily that modulate this process may be important new targets for antiobesity drugs. SUMMARY: Mitochondria play central roles in ATP production, energy expenditure, and disposal of ROS. Excessive energy substrates lead to mitochondrial dysfunction with consequential effects on lipid and glucose metabolism. Adipocytes help to maintain the appropriate balance between energy storage and expenditure and maintaining this balance requires normal mitochondrial function. Many adipokines, including members of the TGF-beta superfamily, and transcriptional coactivators, PGC-1alpha and PRDM16, are important regulators of this process.