Vascular substitute from human placental arteries: glycosaminoglycan and elastin synthesis in the neo-intimal hyperplasia.

Heparinized human placental arteries (internal diameter less than or equal to 1 mm) were cross-linked with glutaraldehyde and implanted in infrarenal aortas in rats (n = 78). At three months and one year following aortic replacement, the neo-intimal hyperplasia covering the patent conduits and the host intima media were excised. Glycosaminoglycans (GAGs) and elastin were metabolically labelled in vitro with radioactive glucosamine and valine, respectively. The incorporation of 3H glucosamine into GAGs decreased sixfold in both neo-intima and host intima media from three months to one year. At three months, the 3H label of hyaluronic acid accounted for 66 per cent and 43 per cent of the 3H GAGs in the neo-intima and host aorta, respectively. At one year, 55 per cent of the 3H GAG label were identified as 3H heparan sulphate in the neo-intima and host intima media. From three months to one year, the ratio of chondroitin 4 sulphate (CS 4) to chondroitin 6 sulphate (CS 6) decreased from 6 to 1.5 in the neo-intima, whilst the ratio of CS 4 to CS 6 (0.6) was constant in the host aorta during the experimental period. At one year, the neo-intima contained elastin. The radioactive incorporation pattern of GAGs and the biosynthetic label of valylproline dipeptides indicated a decrease in biosynthetic activity in neo-intimal and the host aortic cells with progressing time in vivo.