adipócitas

Adipócitas, known in English as adipocytes, are the primary cells of adipose tissue, specialized for lipid storage and endocrine signaling. They originate from mesenchymal stem cells and undergo adipogenesis, a differentiation process driven by transcription factors such as PPARγ and C/EBPα.

There are several adipocyte phenotypes. White adipocytes are large cells with a single lipid droplet that store triglycerides for energy. Brown adipocytes contain many mitochondria and small lipid droplets and generate heat through the protein thermogenin (UCP1). Beige adipocytes are inducible thermogenic cells that arise within white adipose tissue under certain stimuli, such as cold or β-adrenergic signaling.

Adipose tissue is distributed mainly as subcutaneous and visceral depots. The distribution and cellular composition influence metabolic risk: excess visceral fat is more closely linked to obesity-related complications than subcutaneous fat.

Functions of adipocytes extend beyond energy storage. They secrete adipokines, including leptin, adiponectin, resistin, and inflammatory cytokines, which influence appetite, insulin sensitivity, inflammation, and lipid metabolism. Lipolysis in adipocytes releases fatty acids when energy is needed, regulated by enzymes such as hormone-sensitive lipase and ATGL and modulated by insulin and catecholamines.

Clinical relevance: adipose tissue expansion in obesity involves adipocyte hypertrophy and sometimes hyperplasia, often accompanied by chronic low-grade inflammation and metabolic disturbances. Browning of white fat and adipose-derived stem cells are active areas of research with potential therapeutic implications.