Intestine as Source of Cytokines and Growth Factors

Abstract

The activation status of intestinal immune system cells is much higher than that of analogous peripheral cells. Increased serum concentrations of proinflammatory cytokines have been reported in various pathologic conditions; however, the source of these mediators has not been elucidated. To assess the role of the human intestine and its lymphatic system in production of growth factors and proinflammatory cytokines. Twenty liver transplant recipients and 20 donors were included in the study. Blood samples were obtained from the artery supplying the intestine, the portal vein, and a peripheral vein during liver harvesting in donors and after transplantation in recipients. An enzyme-linked immunosorbent assay was used to assess serum concentrations of IL-6, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), and hepatocyte growth factor (HGF). In transplant recipients, IL-6 concentration in arterial blood was lower than that in portal blood (P < .049), whereas in donors, there was no significant difference in these concentrations. Neither recipients nor donors demonstrated significant differences in arterial or portal blood concentrations of TNF-alpha, TGF-beta, or HGF. In healthy human beings, the intestine is not a substantial source of IL-6, TNF-alpha, TGF-beta, or HGF. However, in patients with liver cirrhosis, the intestine is an important source of IL-6 but not of the other studied growth factors and cytokines.