Long-term cryopreserved allogeneic nervous and vascular tissue transfers in monkeys

Four adult Japanese monkeys were used. Donor tissues were harvested from the radial artery, saphenous vein and median nerve, 10 cm in length, and cryopreserved at -196 degrees C in a stepwise manner for long-term preservation for more than 6 months. After rapid thawing of the tissue, the allogeneic tissue transfer was performed of the radial artery to the radial artery, the saphenous vein to the ulnar artery and the median nerve to the median nerve between male and female monkeys. After one year follow-up, angiography was performed and the transferred tissue was harvested for scanning electron microscopic examination and histological examination. As a result, the allogeneic artery in the radial artery was completely patent with no stenosis, whereas there was obstruction of the allogeneic vein in the ulnar artery. Good axonal recovery of the median nerve was observed on histological examination. The cellular structure of neurovascular tissue can be maintained even after long-term cryopreservation. The antigenicity of tissue may be reduced significantly by being frozen, and cryopreserved allogeneic artery can be transferred successfully without the use of immunosuppressive agents. In this report, clinical aspects and the great potential of allogeneic neurovascular tissue transfer, especially in combination with arterial transfer, using cryopreservation are discussed.