ABSTRACT

Obesity is a major problem worldwide whose prevalence is increasing rapidly, with pandemic characteristics. Obesity is fundamentally a problem of energy balance caused by interaction of a series of social, cultural, behavioral and genetic determinants. The etiology or cause of obesity is an imbalance between the energy ingested in food and the energy expended. The excess energy is stored in fat cells that enlarge and/or increase in number. It is this hyperplasia and hypertrophy of fat cells that is the pathological lesion of obesity. Massive development of the adipose tissue leads to the formation of hypoxic areas. The adipose tissue expands and some adipocytes become too distant from the vasculature to be correctly oxygenated. Hypoxia, a deficiency in oxygen (O2), is a major stimulus affecting a number of biological functions, such as angiogenesis, cell proliferation, apoptosis, and inflammation, and it switches cell metabolism from aerobic respiration to anaerobic glycolysis. Hypoxia in obese adipose tissue mediates its effect through the expression of the key hypoxia regulator, hypoxia-inducible factor (HIF), a basic transcription factor composed of two subunits, HIF-α and-β.

KEYWORDS

Obesity, adipose tissue, hypoxia, adipocyte, hypoxia-inducible factor.

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