Freeze-Dried, Decellularized Goat Arterial Allograft

We investigated the fate of decellularized, 3-4-mm-diameter, arterial allografts transplanted in the goat carotid. Eighteen goats received a decellularized, carotid allograft in one carotid and a fresh autologous cephalic vein graft as a control in the other carotid. Half the grafts were explanted at 3 months, and the remainder at 6 months. Patency was 100% for both graft types at both time points. At explant the processed arterial grafts were uniform in diameter without evidence of dilation. In contrast, all autologous vein grafts exhibited dilation with aneurysm formation in a majority of the grafts. Cells lining the graft lumen were positive for Factor VIII, an endothelial cell marker; α-smooth muscle cell actin-positive cells were present in the media, and cells positively staining for vimentin (marker for fibroblasts) were located in the adventitia. The midportion of the processed grafts had significantly less intimal thickness at both time points as compared with vein grafts (48 ± 92 μm vs. 274 ± 213 μm, mean ± SD, respectively, at 3 months, p < 0.02; 13 ± 20 μm vs. 171 ± 64 μm, respectively, at 6 months, p < 0.0001). At the anastomoses, intimal thickness in the processed grafts was comparable to the autologous vein grafts at 3 months (230 ± 41 μm vs. 283 ± 136 μm, respectively) but significantly thicker at 6 months (304 ± 144 μm vs. 144 ± 76 μm, respectively, p < 0.003). Biomechanical analysis showed the processed umimplanted graft to be comparable to fresh artery in strength (maximum stress, 1.8 ± 0.6 and 1.7 ± 0.4 N/mm², respectively) and elasticity (elastic modulus, 0.2 ± 0.03 and 0.3 ± 0.08 N/mm², respectively). The strength of the explanted processed graft at 3 months was significantly greater than preimplant values (maximum stress, 3.8 ± 1.6 N/mm², p < 0.005). The decellularized arterial graft is a potential alternative for arterial replacement.