Relative contribution of the TNF-alpha receptors to murine intimal hyperplasia.

Tumor necrosis factor-alpha (TNF-alpha) is an important mediator in the inflammatory response to vascular injury. The present study sought to determine the relative contribution of each TNF-alpha receptor subtype (p55 and p75) to intimal hyperplasia (IH) and characterize the mechanisms of transcriptional regulation after vascular injury. A murine model of wire carotid arterial injury was employed to induce IH in wild-type (WT), p55-deficient (p55-/-), and p75-deficient (p75-/-) mice. Compared with injured WT and p75-/- animals, p55-/- mice demonstrated a twofold reduction in IH. Additionally, p55-/- mice demonstrated a decrease in expression of nuclear factor-kappaB mRNA and protein. These observations suggest an important role for the p55 receptor in IH after mechanical endoluminal injury. Suppression of the transcriptional activator nuclear factor-kappaB may provide a mechanism by which p55-mediated IH is attenuated.