Rasvakudosta

Rasvakudosta, or adipose tissue, is a loose connective tissue that stores energy in the form of triglycerides within adipocytes. It also provides cushioning and insulation for the body and functions as an active endocrine organ, releasing hormones and cytokines into the bloodstream. The tissue comprises mature adipocytes embedded in a stroma-vasculature that includes preadipocytes, immune cells, extracellular matrix, and blood vessels.

There are several adipose tissue types: white adipose tissue (WAT), brown adipose tissue (BAT), and beige or brite adipose tissue. WAT stores energy as triglycerides and serves an insulating and cushioning role, while BAT specializes in heat production through the action of the mitochondrial protein UCP1. Beige adipocytes can emerge within WAT in response to certain stimuli, such as cold exposure, and also contribute to thermogenesis. In humans, adipose tissue is distributed mainly as subcutaneous fat beneath the skin and visceral fat around internal organs; visceral fat is more strongly associated with metabolic risk than subcutaneous fat.

Beyond energy storage, adipose tissue has endocrine and immunomodulatory functions. Adipocytes secrete adipokines such as leptin and adiponectin, as well as cytokines that influence appetite, glucose and lipid metabolism, insulin sensitivity, and inflammatory processes. The tissue also plays a role in immune responses and offers a reservoir of progenitor cells that can contribute to tissue repair.

Developmentally, adipocytes arise from mesenchymal precursors, with adipogenesis regulated by transcription factors such as PPARγ and C/EBP. Brown and beige adipocytes differ in their development and function and are responsive to sympathetic signaling. Abnormal adipose distribution and dysfunction are linked to obesity, metabolic syndrome, lipodystrophy, and related cardiovascular risks.