Researchers from Harbin Medical University in China and controversial neurosurgeon Sergio Canavero built upon earlier head-grafting experiments to figure out how to avoid damage to the brain tissue during the operation, as well as long-term immune rejection.
Previously, scientists have attempted the procedure on dogs and monkeys, which helped to test neural preservation when blood flood to the brain had been cut off.
The researchers used three rats for each operation: a smaller rat, to be the donor, and two larger rats, acting as the recipient and the blood supply.
To maintain blood flow to the donor brain, they connected the blood vessels from that rat to veins of the third rat using a silicon tube, which was then passed through a peristaltic pump.
According to the team, there was no injury to the donor brain tissue as a result of blood loss in the experiment.
And, after the surgery, the donor head was still able to blink and feel pain.
The two-headed creatures lived 36 hours on average following the procedure.
If they use a peristaltic pump and vascular grafting to the technique, the researchers say long-term survival could be a possibility.
Dr Sergio Canavero plans to conduct tests on human corpses before performing a human head transplant next year. Russian Valery Spiridonov has volunteered to be the first person to have the operation.
A successful cephalosomatic anastomosis (“head transplant”) requires, among others, the ability to control long-term immune rejection and avoidance of ischemic events during the head transference phase. We developed a bicephalic model of head transplantation to study these aspects.
Methods and Results
The thoracic aorta and superior vena cava of a donor rat were anastomosed with the carotid artery and extracorporeal veins of a recipient rat by vascular grafts. Before thoracotomy in the donor rat, the axillary artery and vein of the donor were connected to the carotid and the extracranial vein of the third rat through a silicone tube. The silicone tube was passed through a peristaltic pump to ensure donor brain tissue blood supply. There is no ischemia reperfusion injury in donor brain tissue analyzed by electroencephalogram. Postoperative donor has pain reflex and corneal reflex.
Peristaltic pump application can guarantee the blood supply of donor brain tissue per unit time, while the application of temperature change device to the silicone tube can protect the brain tissue hypothermia, postoperative experimental data show that there is no brain tissue ischemia during the whole operation. The application of vascular grafting can also provide the possibility of long-term survival of the model.