Rj. Pitsch et al., PLATELET-DERIVED GROWTH-FACTOR PRODUCTION BY CELLS FROM DACRON GRAFTSIMPLANTED IN A CANINE MODEL, Journal of vascular surgery, 26(1), 1997, pp. 70-78
Purpose: Previous studies of grafts implanted in dogs documented a tim
e-dependent increase in platelet-derived growth factor (PDGF) producti
on that correlated with inner-capsule thickness. The purpose of this s
tudy was to identify the cells in vascular grafts that produce PDGF. M
ethods: Dacron thoracoabdominal grafts were seeded with autologous end
othelial cells (ECs), implanted in 11 beagles, and removed after 4 or
20 weeks. ECs and smooth muscle cells (SMCs) were cultured from grafts
and adjacent aorta, and PDGF in the conditioned media was measured by
radioreceptor assay. The PDGP A-chain mRNA level in freshly harvested
cells was assessed using reverse transcriptase, followed by polymeras
e chain reaction, and expressed as a ratio of glyceraldehyde-3-phospha
te dehydrogenase signal. Localization of PDGF A-chain and B-chain prot
ein was also examined with immunohistochemical analysis. Results: Graf
t and aortic ECs hi primary culture did not produce significantly diff
erent amounts of PDGF in 72 hours, averaging 368 +/- 160 and 340 +/- 8
1 pg/mu g DNA, respectively. Graft SMCs in primary culture produced si
gnificantly more PDGF than aortic SMCs (584 +/- 43 and 113 +/- 94 pg/m
u g DNA, respectively; P < 0.01). Graft SMC PDGF secretion remained gr
eater than aortic SMC PDGF secretion through at least six cell passage
s. PDGF A-chain mRNA levels were not significantly different for aorti
c or graft ECs. The PDGF A-chain mRNA level was significantly higher f
or graft SMCs than aortic SMCs (2.44 +/- 0.67 and 1.45 +/- 0.57 pg/mu
g, respectively; P < 0.03). Immunocytochemical analysis detected PDGF
A-chain and B-chain protein in the ECs from both native aorta and graf
t as well as the subendothelial SMCs in the graft, but not in the SMCs
of the native aorta. Conclusions: These results suggest that graft SM
Cs are functionally altered, producing more PDGF than aortic SMCs. PDG
F produced by graft SMCs may contribute to the development of intimal
hyperplasia.