Hypoxia and the endocrine and signalling role of white adipose tissue

Abstract

White adipose tissue is a major endocrine and signalling organ. It secretes multiple protein hormones and factors, termed adipokines (such as adiponectin, leptin, IL-6, MCP-1, TNFα) which engage in extensive cross-talk within adipose tissue and with other tissues. Many adipokines are linked to inflammation and immunity and these include cytokines, chemokines and acute phase proteins. In obesity, adipose tissue exhibits a major inflammatory response with increased production of inflammation-related adipokines. It has been proposed that hypoxia may underlie the inflammatory response in adipose tissue and evidence that the tissue is hypoxic in obesity has been obtained in animal models. Cell culture studies have demonstrated that the expression and secretion of key adipokines, including leptin, IL-6 and VEGF, are stimulated by hypoxia, while adiponectin (with an anti-inflammatory action) production falls. Hypoxia also stimulates glucose transport by adipocytes and may have a pervasive effect on cell function within adipose tissue.

Key words:

• Adipocyte
• adipokine
• hypoxia
• inflammation
• oxygen
• white adipose tissue

Acknowledgements

We are grateful to the BBSRC (UK) for funding for our studies on hypoxia. P. Trayhurn is a member of COST BM0602.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.