The migratory response to platelet-derived growth factor of smooth muscle cells isolated from synthetic vascular grafts in a canine model

Objective: Previous studies on smooth muscle cells (SMCs) harvested from implanted synthetic grafts demonstrate increased production of platelet- derived growth factor (PDGF) but decreased proliferative response compared with aortic SMCs. The purpose of this study was to determine the migratory response of graft versus aortic SMCs. Methods: Thoracoabdominal grafts were implanted in beagles. The SMCs were harvested from the graft and infrarenal aorta. Migration was determined with the use of a razor-scrape assay and computerized image analysis. Results: The mean distance migrated and the number of cells that migrated were greater in graft SMCs at baseline (185 ± 18 μm and 108 ± 17 cells) compared with aortic cells (110 ± 10 μm and 42 ± 5 cells)(P < .05). Baseline differences persisted after treatment with antibodies to PDGF. The addition of PDGF (10 ng/mL) resulted in increased migration in both graft (229 ± 23 μm and 146 ± 20 cells) and aortic SMCs (130 ± 9 μm and 70 ± 5 cells) compared with baseline (P < .05). The relative increase in response to PDGF was similar between the two groups (P = not significant). Conclusions: Graft SMCs differ phenotypically from aortic SMCs; they exhibit increased basal migration that is independent of autocrine stimulation by PDGF. In contrast to their blunted proliferative response, graft SMCs have a similar migratory response to PDGF compared with aortic SMCs.