State of the art paper Biochemistry of adipose tissue: an endocrine organ

Abstract

Adipose tissue is no longer considered to be an inert tissue that stores fat.This tissue is capable of expanding to accommodate increased lipids through hypertrophy of existing adipocytes and by initiating differentiation of pre-adipocytes.Adipose tissue metabolism exerts an impact on whole-body metabolism.As an endocrine organ, adipose tissue is responsible for the synthesis and secretion of several hormones.These are active in a range of processes, such as control of nutritional intake (leptin, angiotensin), control of sensitivity to insulin and inflammatory process mediators (tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), resistin, visfatin, adiponectin, among others) and pathways (plasminogen activator inhibitor 1 (PAI-1) and acylation stimulating protein (ASP) for example).This paper reviews some of the biochemical and metabolic aspects of adipose tissue and its relationship to inflammatory disease and insulin resistance.K Ke ey y w wo or rd ds s: : adipose tissue, adipocytes, adipokines. Adipose tissueOriginally considered as simply a storage organ for triacylglycerol, interest in the biology of adipose tissue has increased substantially.Over the last decades there has been considerable accumulation of experimental data about the biology and biochemistry of adipose tissue.This tissue is no longer considered to be an inert tissue that just stores fat [1].Adipose tissue is a metabolically dynamic organ that is the primary site of storage for excess energy but it serves as an endocrine organ capable of synthesizing a number of biologically active compounds that regulate metabolic homeostasis.This dynamic tissue is composed not only of adipocytes, but also of other cell types called the stroma-vascular fraction, comprising blood cells, endothelial cells, pericytes and adipose precursor cells among others [2][3][4][5].Several studies have evidenced that adipose tissue is not uniform.Depending on the location in the body, they differ in their capacity to secrete adipocytokines, as well as cellular composition with varied phenotype, as well as the quantity and proportion of adipocytes forming it, blood vessel stromal cells and immune system cells [6].It is now generally recognized that adipose tissue is an important organ of a complex network that participates in the regulation of a variety of quite diverse biological functions (Figure 1) [7-10].C Co or rr re es sp po on nd di in ng g a au ut th