StemCell Therapy

Adipocytes, also known as lipocytes and fat cells, are the cells that primarily compose adipose tissue, specialized in storing energy as fat.

There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white fat and brown fat, respectively, and comprise two types of fat cells. Most recently, the presence of beige adipocytes with a gene expression pattern distinct from either white or brown adipocytes has been described. Also another special type of adipose tissue is being studied, pink adipose tissue, which seems to be involved in mammary duct development in female breasts. [1][2]

White fat cells or monovacuolar cells contain a large lipid droplet surrounded by a layer of cytoplasm. The nucleus is flattened and located on the periphery. A typical fat cell is 0.1mm in diameter with some being twice that size and others half that size. The fat stored is in a semi-liquid state, and is composed primarily of triglycerides and cholesteryl ester. White fat cells secrete many proteins acting as adipokines such as resistin, adiponectin, leptin and Apelin. An average human adult has 30 billion fat cells with a weight of 30lbs or 13.5kg. If excess weight is gained as an adult, fat cells increase in size about fourfold before dividing and increasing the absolute number of fat cells present.[3]

Brown fat cells or plurivacuolar cells are polygonal in shape. Unlike white fat cells, these cells have considerable cytoplasm, with lipid droplets scattered throughout. The nucleus is round, and, although eccentrically located, it is not in the periphery of the cell. The brown color comes from the large quantity of mitochondria. Brown fat, also known as "baby fat," is used to generate heat.

Pre-adipocytes are undifferentiated fibroblasts that can be stimulated to form adipocytes. Recent studies shed light into potential molecular mechanisms in the fate determination of pre-asipocytes although the exact lineage of adipocyte is still unclear.[4][5]

Mesenchymal stem cells can differentiate into adipocytes, connective tissue, muscle or bone.

Areolar connective tissue is composed of adipocytes.

The term "lipoblast" is used to describe the precursor of the adult cell. The term "lipoblastoma" is used to describe a tumor of this cell type.[6]

Even after marked weight loss, the body never loses adipocytes. As a rule, to facilitate changes in weight, the adipocytes in the body merely gain or lose fat content. However, if the adipocytes in the body reach their maximum capacity of fat, they may replicate to allow additional fat storage.

Adult rats of various strains became obese when they were fed a highly palatable diet for several months. Analysis of their adipose tissue morphology revealed increases in both adipocyte size and number in most depots. Reintroduction of an ordinary chow diet[clarification needed] to such animals precipitated a period of weight loss during which only mean adipocyte size returned to normal. Adipocyte number remained at the elevated level achieved during the period of weight gain.[7]

Excerpt from:
Adipocyte - Wikipedia, the free encyclopedia

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