RESUMO
The vascular hallmark of chronic rejection (CR), as well as of atherosclerosis, is initial hyperplasia. It results from migration and proliferation of vascular smooth muscle cell and increased deposition of extracellular matrix proteins. A possible mechanism responsible for formation of neointima is the release of growth factors and cytokines, such as: transforming growth factor beta (TGF-beta), tumour necrosis factor alfa (TNF-alpha), interleukin 1 (IL-1) and interleukin 6 (IL-6). The expression of these factors in the renal artery wall of chronically rejected allografts was quantified. The renal artery samples were obtained from patients with chronic renal allograft rejection, undergoing graftectomy (n = 11) and patients with autosomal dominant polycystic kidney disease (ADPKD), undergoing nephrectomy (n = 4). Total RNA was isolated and the expression of mRNA for TGF-beta, TNF-alpha, IL-1 and IL-6 was measured using a real time PCR. In patients with CR the expression levels of TGF-beta, TNF-alpha and IL-1 mRNA were higher than in control group. No difference between groups was detected for IL-6. In both groups a correlation was detected between age and TGF-beta expression. The increased expression of TGF-beta, TNF-alpha and IL-1 may be a key factor in the neointimal formation and pathogenesis of CR. The increase in the TGF-b expression with age might be a protective mechanism in atherosclerosis.
