Evaluation of anastomotic hyperplasia progression using the cyclin specific antibody MIB-1

Background Delayed failure of prosthetic arterial grafts is primarily due to the development of anastomotic intimai hyperplasia. This report follows the proliferation of smooth muscle cells that ensues after prosthetic arterial grafting, using the cyclin-specific antibody MIB-1. Methods Six-mm expandable polytetrafluoroethylene (ePTFE) grafts were placed end-to-end in the carotid arteries of mongrel dogs. Animals were randomly assigned to sacrifice intervals of 2, 7, 14, and 30 days. Serial coronal sections were cut and immunohistocytochemistry performed using the MIB-1 antibody. Results The control carotid artery had no definable proliferation. Two days after grafting, there was brisk proliferation in the upper one third of the arterial media. By 7 days, proliferation and migration of smooth muscle cells was seen above the internal elastic lamina, in which 50% of the cells were MIB-1 positive. Fourteen days after graft placement, proliferation continued in the neointima; however, the proliferation index was diminished compared with previous time intervals. At 30 days, despite a dramatic increase in lesional increase, there was a marked decrease in the overall proliferation of cells. Conclusions Following placement of a prosthetic arterial graft, there is initial brisk proliferation of cells in the arterial media, with migration, ongoing proliferation, and resultant development of a localized cellular neointima. Over a 30-day period, the percentage of cells proliferating subsides in contrast to the progressive increase in the size of the neointima. Immunohistocytochemistry with the MIB-1 antibody is a useful tool in defining the cellular kinetics after prosthetic arterial grafting.