Article Number: PRJA13407592


Vol. 1 Issue 3, pp: (25-40), December 2016.
Article Number: PRJA13407592
Copyright ©2016
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Review

Adipose tissue significance with special emphasis on its role in regulating immune functions in mammals

M. K. Vidya1, Girish Kumar1, Madiajagan Bagath2, Govindan Krishnan2, R.K. Veeranna2, K.K. Sunil Kumar1, Veerasamy Sejian2* and Raghavendra Bhatta2

1Veterinary College, Karnataka Veterinary Animal and Fisheries Sciences University, Hebbal, Bangalore-560024, India.

2ICAR-National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore-560030, India.

*Corresponding Author. E-mail: drsejian@gmail.com

 Received: July 23, 2016  Accepted: November 13, 2016  Published: December 28, 2016

ABSTRACT

This review attempts to cover the implication of the adipose tissue in controlling immune functions with emphasis on the structure and properties of adipose tissue, adipokines produced by adipose tissue, immune cells in adipose tissue and molecular mediators of adipose tissue inflammation. Adipose tissue (AT) in mammals is a complex, multi-depot, anatomically dissectible discrete structure with high metabolic activity. Both excess and deficiency of adipose tissue affect the normal homeostasis of the body.  The AT comprises of two types of adipocytes, white adipocytes which store lipids whereas brown adipocytes which oxidize these lipids to produce heat. Further, to serving as a fat depot, AT also serves as endocrine adipose organ producing many bioactive molecules, called adipokines. These adipokines include leptin, adiponectin, visfatin, apelin, vaspin, omentin, resistin, hepacidin, monocyte chemoattractant protein (MCP), interleukin 6 (IL-6), tumor necrosis factor (TNF-α), plasminogen activator inhibitor (PAI-1) and other cytokines. Leptin is by far the most important endocrine parameter produced which regulates feed intake and considered as nutritional signal in mammals. In addition, leptin also was also found to be associated with controlling puberty, immunity, and autoimmune disorders. Adiponectin was found to be another noteworthy molecule produced from AT which increases fatty acid oxidation and reduces the synthesis of glucose in the liver. Further, adiponectin was found to have an anti-diabetic, anti-inflammatory and anti-atherogenic effect. A strong interplay between AT and immunity was established in mammals. Recently it was established that AT plays a huge role in controlling the immune functions in mammals through its close association with lymphoid organs; secreting inflammatory cytokines and adipokines; and through its anti-microbial and phagocytic activities. The involvement of AT in controlling immunity and autoimmune disorder was reported to be a significant breakthrough in cancer biology. Hence, it may be concluded that apart from acting as a fat depot to control energy metabolism, AT was also found to be associated with several other important biological functions signifying its role as an important endocrine organ in mammals.

Key words: Adipose tissue, Auto-immune disorder, Leptin, Adipokines, Immunity, Interleukins.