Pathological conditions have been recognized where vessel destruction is a prominent feature of the pathogenic process. One
such condition consists of the chronic rejection of blood vessels in transplanted solid organs. Accelerated graft arteriosclerosis
(AGA) is a multifactorial process characterized by the concentric proliferation of smooth muscle cells (SMCs) within the intima
of the vessel wall of transplanted organs. Proliferation of SMCs within the intima corresponds to a response of these cells
to injury. In situations like restenosis post-angioplasty, the mechanism of injury: the mechanical disruption of the tunica
media, is evident. However, in the case of AGA, the mechanism of injury has remained elusive. In this report, we provide evidence
that injury to SMCs in AGA vessels requires an intact Fas pathway. The resulting damage to the tunica media and internal elastic
lamina, in turn, might trigger the proliferation of intimal smooth muscle cells that appear to be less sensitive to Fas mediated
killing, particularly when supported by a favorable context of inflammatory cytokines and growth factors, as it is the case
in AGA. This pathogenic process results in a absolute loss of functional blood vessels that is not being compensated by an
efficient angiogenic response.
apoptosis - chronic rejection - Fas - Fas-ligand - lpr - smooth muscle cells - transplant - vasculopathy
This revised version was published online in June 2006 with corrections to the Cover Date.