Neointimal Smooth Muscle Cells in Mouse Vein Grafts Are Not Recruited from the Adjacent Artery.

INTRODUCTION

Smooth muscle cells (SMCs) with an origin separate from the local vein wall contribute to formation of intimal hyperplasia (IH) in mouse vein grafts. The recruitment pathway of these cells has not been defined, but circulating progenitor cells and cells from the surrounding tissue or adjacent artery to which the vein graft is anastomosed are potential sources. The aim of this study was to clarify if cells from the adjacent artery contribute to neointimal formation in vein grafts.

METHODS

Aortic segments from donor SM22α-LacZ mice were anastomosed to vein segments from wild-type (WT) C57BL/6 mice ex vivo followed by implantation of the composite grafts to the right common carotid arteries of WT recipient mice. Six weeks after surgery, the composite grafts were harvested, and histology was analyzed in longitudinal sections. SMCs with origin in the SM22α-LacZ arterial segments were identified with X-gal staining.

RESULTS

LacZ-positive cells were found in the medial layer of the SM22α-LacZ arterial segments but were not found in the IH in the vein graft segment.

CONCLUSION

SMCs in vein grafts are not recruited from the adjacent artery through migration across the anastomosis.