Interplay between the immune system and adipose tissue in obesity

    1. Lydia Lynch4
    1. 1Department of Medicine, Brigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USA
      2Faculty of Medical and Human Sciences, Manchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UK
      3Department of Endocrinology, St. Vincent's University Hospital, University College Dublin, Dublin, Ireland
      4Department of Medicine, Brigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA
    1. Correspondence should be addressed to M A Exley; Email: mexley{at}


    Obesity is a major risk factor for metabolic disease, with white adipose tissue (WAT) inflammation emerging as a key underlying pathology. Alongside its major role in energy storage, WAT is an important endocrine organ, producing many bioactive molecules, termed adipokines, which not only serve as regulators of systemic metabolism, but also possess immunoregulatory properties. Furthermore, WAT contains a unique immune cell repertoire, including an accumulation of leukocytes that are rare in other locations. These include alternatively activated macrophages, invariant natural killer T cells, and regulatory T cells. Disruption of resident adipose leukocyte homeostasis contributes to obesity-associated inflammation and consequent metabolic disorder. Despite many recent advances in this new field of immuno-metabolism, fundamental questions of why and how inflammation arises as obesity develops are not yet fully understood. Exploring the distinct immune system of adipose tissue is fundamental to our understanding of the endocrine as well as immune systems. In this review, we discuss the roles of adipose tissue leukocytes in the transition to obesity and progression of inflammation and highlight potential anti-inflammatory therapies for combating obesity-related pathology.

    • Received in final form 20 August 2014
    • Accepted 15 September 2014
    • Made available online as an Accepted Preprint 16 September 2014
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