Role of peroxisome proliferator-activated receptor γ and retinoid X receptor heterodimer in hepatogastroenterological diseases

The peroxisome proliferator-activated receptor gamma (PPAR-gamma) and its partner the retinoid X receptor (RXR) are two nuclear receptors that are expressed mainly in adipose tissue and which have a role in lipid metabolism and insulin sensitisation. New sites of PPARgamma/RXR expression have been described, especially in the intestinal tract, pancreas, and liver. Concomitantly, new functions have been attributed to this heterodimer in regulation of inflammation, by its inhibition of nuclear factor (NF)-kappaB and via stress-kinase pathways. These new sites and functions of PPARgamma/RXR have led to novel ideas about pathophysiology of different inflammatory digestive diseases and to development of innovative treatment strategies with PPARgamma activators.