The Mighty Mitochondria: Revisiting the Cell's Workhorse in Adipose Tissue

New evidence indicates that mitochondria are a crucial element in metabolic homeostasis in white adipocytes. They appear to have significant involvement in adipogenesis, fatty acid synthesis and esterification, branched-chain amino acid catabolism, and lipolysis

Mitochrondria, tiny organelles within the cell, are the major source of cell energy, and recent research indicates that mitochondria have more expansive roles than previously believed. Most scientists ignored their roles in white adipose tissue (WAT) because that type of tissue has fewer mitochondria, and the general belief was that mitochondira simply held excess nutrients.

New evidence indicates that mitochondria are a crucial element in metabolic homeostasis in white adipocytes. They appear to have significant involvement in adipogenesis, fatty acid synthesis and esterification, branched-chain amino acid catabolism, and lipolysis. Endocrinologists from the University of Utah School of Medicine describe the progress in understanding WAT mitochondria in a recent electronic publication in Experimental Physiology.

The importance of mitochondrial function in WAT is simple: WAT function can be perturbed by altering mitochondrial components or oxidative capacity. The authors note that humans and animals that have significant obesity or lipoatrophy appear to be at an increased risk of metabolic diseases such as diabetes and insulin resistance. That risk has been theoretically linked to impaired mitochondrial function in adipocytes, and these authors argue that impaired mitochondrial function is not related to systemic insulin resistance.

The authors describe recent studies that specifically targeted WAT mitochondrial function; mitochrondia seem to integrate metabolic signals that can reprogram several processes and alter whole body physiology. They propose that reduced mitochondrial electron transport chain activity alone (without reactive oxygen species generation) and mitochondrial dysfunction (usually associated with reactive oxygen species generation) are responsible for many intracellular changes.

Although technical in nature, this article reminds us that cellular components often create systemic disease. It also contributes to the growing notion that adipose tissue becomes an endocrine organ in its own right over time. Eventually, alternations in adispose tissue may be a drug target to address our growing epidemic of diabetes and obesity.

SOURCE: Boudina S, Graham TE. Mitochondrial function/dysfunction in white adipose tissue. Exp Physiol. 2014 Aug 15. [Epub ahead of print]