Endocrine Abstracts

Introduction: Allograft inflammatory factor 1 (AIF-1) is a putative obesity gene which may influence the function of white adipose tissue (WAT).

Objective: To study the role of AIF-1 in human WAT.

Design and main outcome measures: mRNA expression and WAT secretion of AIF-1 was determined in subcutaneous and visceral WAT from non-obese subjects. Differentiated human adipocytes were treated with recombinant AIF-1 in vitro.

Results: AIF-1 was secreted in a time dependent fashion from WAT. The major source of AIF-1 was macrophages followed by lymphocytes; fat cells contributed only to a minimum extent. Expression of AIF-1 was similar in visceral and subcutaneous WAT and was markedly increased in obese subjects; the latter was normalized following weight reduction. AIF-1 stimulated the adipocyte production and secretion of monocyte chemoattractant protein 1 (MCP-1) without influencing other proteins involved in inflammation.

Conclusion: AIF-1 is a novel adipokine involved in the pathophysiology of obesity. It is produced mainly by macrophages within WAT and i. It’s expression is increased in obesity as a secondary phenomenon. AIF-1 may play a paracrine role in the inflammation of WAT through cross-talk between macrophages and fat cells, by enhancing adipocyte production and secretion of MCP-1.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.