Email updates

Keep up to date with the latest news and content from BMC Endocrine Disorders and BioMed Central.

Open Access Research article

Allograft inflammatory factor 1 (AIF-1) is a new human adipokine involved in adipose inflammation in obese women

Silvia Lorente-Cebrián1*, Pauline Decaunes2, Elisabeth Dungner1, Anne Bouloumié2, Peter Arner1 and Ingrid Dahlman1

Author Affiliations

1 Department of Medicine Huddinge, Lipid Laboratory, Novum, Karolinska Institutet, Karolinska University Hospital, SE-141 86 Huddinge, Stockholm, Sweden

2 Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Institut des maladies cardiovasculaires et métaboliques, Université Toulouse III Paul-Sabatier, Toulouse, France

For all author emails, please log on.

BMC Endocrine Disorders 2013, 13:54  doi:10.1186/1472-6823-13-54

Published: 25 November 2013

Abstract

Background

Allograft inflammatory factor 1 (AIF-1) is a putative obesity gene. Our aim was to examine the expression of AIF-1 in human white adipose tissue (WAT) in relation to obesity and metabolic phenotypes in women.

Methods

WAT secretion of AIF-1 was determined in subcutaneous adipose tissue pieces in vitro by ELISA from 5 subjects. mRNA expression of AIF-1 was determined by RT-qPCR in the isolated cell fractions of adipose tissue (n = 5-6 per group), in subcutaneous and visceral WAT pieces from non-obese (n = 12) and obese women (n = 23), and in some subcutaneous WAT also before and after weight reduction (n = 10). Finally, adipose AIF-1 mRNA was related to metabolic phenotypes in 96 subjects with a wide range of BMI.

Results

AIF-1 was secreted in a time dependent fashion from WAT. The major source of AIF-1 was WAT resident macrophages. Expression of AIF-1 was similar in visceral and subcutaneous WAT and was two-fold increased in obese women (P < 0.01). AIF-1 mRNA expression levels were normalized after weight reduction (P < 0.01). Expression of AIF-1 was inversely correlated with insulin sensitivity as assessed by insulin tolerance test (KITT), and circulating levels of adiponectin (P = 0.02), and positively correlated with insulin resistance as estimated by HOMA (=0.0042).

Conclusions

AIF-1 is a novel adipokine produced mainly by macrophages within human WAT. Its expression is increased in obese women and associates with unfavourable metabolic phenotypes. AIF-1 may play a paracrine role in the regulation of WAT function through cross-talk between macrophages and other cell types within the adipose tissue.

Keywords:
AIF-1; Adipokines; Obesity; Adipose tissue