In patients with lipodystrophy, higher levels of tumour necrosis factor (TNF)-α, interleukin-6 (IL-6) and IL-18 have been reported in both systemic and adipose tissue expression [6]. Recently, a newly discovered adipokine, fatty acid binding protein 4 (FABP-4; also called aP2), has emerged as an important mediator in the cross-talk between adipocytes and macrophages in adipose tissue. It belongs to the family of fatty Cyclopamine chemical structure acid binding proteins (FABPs) which are a group of molecules that co-ordinate lipid responses in cells and are also connected to metabolic and inflammatory pathways. FABPs are lipid chaperones that bind fatty acid ligands with high

affinity and have functions in intracellular fatty acid trafficking, regulation of lipid metabolism, and modulation of gene expression [7,8]. FABP-4 is abundantly expressed in mature adipocytes and activated macrophages [9,10]. FABP-4-deficient mice exhibit higher insulin-stimulated glucose uptake and their adipocytes have a reduced efficiency of lipolysis, Apoptosis inhibitor both in vivo and in vitro. Furthermore, studies of FABP-4 gene variants suggest that FABP-4 may have effects on plasma lipid levels and insulin sensitivity, and play a role in coronary heart disease [9,10]. All these data suggest that FABP-4 could be a potential target for the treatment of metabolic diseases. Although it was once thought to be a purely

intracellular protein, recent studies have shown

FABP-4 to be present at high levels in human serum [11]. In cross-sectional analyses, circulating ifenprodil FABP-4 has been closely associated with obesity and metabolic syndrome, and in prospective studies FABP-4 levels predicted the development of metabolic syndrome and type 2 diabetes [11]. Data for HIV-1-infected patients are scarce. A recent study that included HIV-1-infected patients with metabolic syndrome and lipodystrophy showed that these patients had higher circulating levels of FABP-4 than those without metabolic syndrome or lipodystrophy, although the relationship with insulin resistance and other well-known inflammatory and adipocyte-related cytokines was not explored [12]. Considering that FABP-4 seems to be a key element in adipocyte differentiation, and that it has been postulated as a possible marker of fat distribution in mammals [13], we have hypothesized that FABP-4 may be involved in cART-related lipodystrophy syndrome and its associated metabolic disturbances in HIV-1-infected patients. We have therefore analysed the circulating levels of FABP-4 in an HIV-1-infected cohort including patients with and without lipodystrophy. A multicentre cross-sectional case–control study was carried out. A total of 467 individuals were included in the study, all of whom were Caucasian adults, with 282 being HIV-1-infected and 185 uninfected.