Rp. Baer et al., RETROVIRAL-MEDIATED TRANSDUCTION OF ENDOTHELIAL-CELLS WITH THE LAC-Z GENE IMPAIRS CELLULAR PROLIFERATION IN-VITRO AND GRAFT ENDOTHELIALIZATION IN-VIVO, Journal of vascular surgery, 24(5), 1996, pp. 892-899
Purpose: An endothelialized lumen within a synthetic graft that expres
ses recombinant proteins with anticoagulant or antiproliferative activ
ity has the potential to improve graft function. However, preliminary
data suggest that-genetic modification of endothelial cells (ECs) impa
irs their proliferation. The purpose of this investigation was to test
the hypothesis that retroviral transduction of cultured ECs with the
lac Z gene encoding for beta-galactosidase would decrease EC prolifera
tion in vitro and graft endothelialization in vivo. Methods: In vitro
studies compared canine EC proliferation over a 14-day period among ea
rly-passage ECs (two and three) and late-passage ECs (six and nine) tr
ansduced with the BAG vector (containing the lac Z gene and the neomyc
in resistance gene), ECs transduced with the neomycin resistance gene
only, and nontransduced ECs. In vivo canine studies assessed endotheli
alization of expanded polytetrafluoroethylene thoracoabdominal grafts
seeded with autologous lac Z-transduced ECs (n = 7) or nontransduced E
Cs (n = 3) compared with that of nonseeded grafts (n = 3). Histochemic
al staining and DNA polymerase chain reaction was used 6 weeks after i
mplantation to detect the presence of the lac Z gene in the grafts' ce
llular Linings and perigraft tissues. Endothelialization was assessed
by Light microscopy and electron microscopy. Results: Proliferation of
late-passage lac Z-transduced ECs in vitro was significantly decrease
d compared with neomycin resistance-transduced ECs or nontransduced EC
s. Among early-passage ECs smaller but significant decreases in prolif
eration were noted among (Rc Z-transduced cells compared with nontrans
duced cells. Six of seven expanded polytetrafluoroethylene grafts seed
ed with transduced ECs showed lac Z gene expression. Lac Z gene expres
sion mas not found on grafts seeded with nontransduced ECs or nonseede
d grafts. The endothelialized luminal surface area was significantly l
ess in grafts seeded with lac Z-transduced ECs compared with grafts se
eded with nontransduced ECs. Conclusions: Retroviral-mediated transduc
tion of canine ECs with the lac Z gene encoding for beta-galactosidase
impairs EC proliferation in vitro and the ability of transduced ECs t
o form a confluent EC monolayer on the luminal surface of synthetic gr
afts in vivo.