Allogenic immune response promotes the accumulation of host-derived smooth muscle cells in transplant arteriosclerosis.

Objective: Smooth muscle cells (SMCs) involved in intimal hyperplasia during transplant vasculopathy are derived both from the graft and the host. Here, the role of an allogenic immune response in the accumulation of host-derived SMCs in the neointima was explored.

Methods: Infrarenal aorta was transplanted from female F344 to male Lewis rats with or without immunosuppression by cyclosporine A (CsA).

Smooth-muscle progenitor cells of bone marrow origin contribute to the development of neointimal thickenings in rat aortic allografts and injured rat carotid arteries.

This study indicates that circulating progenitors of bone marrow origin give rise to cells with smooth muscle-like properties during formation of neointimal thickenings in the arterial wall after allotransplantation and after balloon injury. A segment of abdominal aorta was transplanted from female F344 to male LEW rats, and the grafts were analyzed for male cells by using the gene as a marker. Immunostaining demonstrated that CD45-positive leukocytes made up 35-45% of the neointimal cells during the 8-week period examined.