A head transplant may sound like something out of a horror movie, but Dr. Xiaoping Ren has completed about 1,000 on mice. This summer, he'll attempt his first such procedure on a monkey in a case that will be closely watched. Ren, who worked in the US for more than 15 years, may conduct the experiment in his native China, where he has worked since 2012 with the government's strong support and $1.6 million in grants, as Beijing seeks to become what the Wall Street Journal calls a "scientific powerhouse." Such a test may not even be possible in America, where other controversial Chinese research has met with harsh criticism. An animal rights group tells the Daily Mirror Ren's mice experiments alone are "cruel and medically absurd." In China, those concerns take a backseat to hopes that human head transplants can one day help those with spinal-cord injuries, cancer, and other diseases. But first, "we have to make an animal model with long-term survival," says Ren, 53.
Mice with transplanted heads have survived for at most a day. Ren, who will collaborate with another surgeon interested in human head transplants, first makes a clean cut to detach the donor head from its body, while the head of the body to be donated is separated at midbrain so the heart can remain beating. Blood vessels from the donor body are then attached to the recipient head using silicone tubes before the head's spinal nerves are connected. The bone from the connecting vertebrae is rebuilt with pins, screws, and plates, then the blood vessels, muscle, and skin are joined with microscopic sutures. When Ren turns his procedure to monkeys—long-tailed macaques, specially—he will aim to connect just 10% to 20% of 100 billion spinal-nerve fibers—enough to allow the monkey to breathe and move muscles voluntarily. Should Ren eventually reach the "next frontier" with human transplants, a much higher percentage of connections will be needed. (Think the idea is crazy? You're not alone.)