Effect of Retroviral Transduction of Canine Microvascular Endothelial Cells on β 1 Integrin Subunit Expression and Cell Retention to PTFE Grafts

Abstract

This study evaluated the effect of retroviral transduction on canine microvascular endothelial cell (CMVEC) detachment from fibrin glue coated expanded polytetrafluoroethylene (ePTFE) graft material. CMVEC were isolated from adipose tissue by fluorescent activated cell sorting (FACS). Three treatment groups were evaluated: G-I, transduced CMVEC, selected in antibiotic G418 for 10 days (n=5); G-II, CMVEC selected in G418 and recovered from selection for 4 days (n=5): and G-III, control group of naive CMVEC (n=6). ³H-thymidine labeled endothelial cells were seeded on fibrin glue coated four-mm diameter PTFE. Grafts were exposed to physiologic shear stresses of 16 dyn/cm². Cell detachment was determined by ³H-thymidine counts in the circuit effluent. β₁ integrin subunit expression was measured by flow cytometry. After 2 hours of flow exposure, G-I and G-II demonstrated significantly greater cell detachment rates compared with the control seeded grafts. Median peak channel β₁ integrin subunit value for G-III CMVEC was 2311±481.7 vs. 31.5±4.51 and 26.3±2.0 in the transduced cell groups (p=0.00043). Low β₁ integrin expression correlated with flow induced high detachment rates of retrovirally-transduced CMVEC.