Adipose tissue fibrosis.

The increasing prevalence of obesity causes a major interest in white adipose tissue biology. Adipose tissue cells are surrounded by extracellular matrix proteins whose composition and remodeling is of crucial importance for cell function. The expansion of adipose tissue in obesity is linked to an inappropriate supply with oxygen and hypoxia development. Subsequent activation of hypoxia inducible factor 1 (HIF-1) inhibits preadipocyte differentiation and initiates adipose tissue fibrosis. Thereby adipose tissue growth is limited and excess triglycerides are stored in ectopic tissues. Stressed adipocytes and hypoxia contribute to immune cell immigration and activation which further aggravates adipose tissue fibrosis. There is substantial evidence that adipose tissue fibrosis is linked to metabolic dysfunction, both in rodent models and in the clinical setting. Peroxisome proliferator activated receptor gamma agonists and adiponectin both reduce adipose tissue fibrosis, inflammation and insulin resistance. Current knowledge suggests that antifibrotic drugs, increasing adipose tissue oxygen supply or HIF-1 antagonists will improve adipose tissue function and thereby ameliorate metabolic diseases.