Science and medicine have come a long way when it comes to transplants. In the body, there are more organs that can be transplanted than not. In fact, it is now possible to transplant any organ except one: the brain. Today it is not possible to perform brain transplants, nor is it believed that it will be possible in a few years, if it ever is.
What is the reason for this limitation?
Suppose we have overcome the difficult task of finding a compatible donor , which sounds easier said than done. Once this problem is overcome, one of the main difficulties lies in how to connect this new brain to the spinal cord. Most transplant surgeries depend on a correct connection (anastomosis) between blood vessels, but the case of the spinal cord is considerably more complex. The movement of the whole body depends on it. The spinal cord is a network of nerve cells called neurons, which transmit information to and from the brain. Any mistake or mishap during surgery could be irreversible, because if the neurons are damaged, there is no going back. The cells of the central nervous system are unable to regenerate. That’s why severe spinal cord injuries are often permanent. So the risks are not few or slight: the slightest inconvenience could determine a fatal error.
Added to this problem are the ethical debates , which question what the identity of the transplant recipients would be, since their memory, conscience and emotions would be affected. What is called an “identity transplant”. We also find ourselves with the moral dilemma involved in keeping alive a body whose brain has died.
For all this, today this transplant is unfeasible. Fortunately, there are more realistic and feasible options in cases of brain damage, which do not involve a whole brain transplant. It’s about cell replacement. This consists of transplanting individual cells into an organ or tissue so that they restore normal function. In other words, it consists of treating a disease by replacing damaged cells or tissues.
This type of therapy is usually used in patients with hereditary or degenerative diseases.
Building on this treatment, scientists are experimenting with cell therapies that could allow neurons to regenerate and grow. This could stop, or in some cases even reverse, a degenerative disease of the cellular tissue of the brain or nervous system. A treatment like this could be useful for patients with dementia or multiple sclerosis.
Despite this, there are those who insist that it is worth continuing to try brain transplants, because they maintain that they could be possible.
How could we make a brain transplant possible?
Transplanting, not only the brain, but also the spinal column . Experts believe this can be successfully done in about 10 years , with advances in robotic surgery and stem cell transplants.
Moreover, there are those who propose a complete head transplant . That is, when it is the body that fails in an individual with a healthy brain, their head could be removed and placed in a donated body. However, this procedure is highly questioned and there are many who do not believe that it is possible. In the first place because they consider it more a transplant of the body than of the brain. Because in reality we would be implanting the body of a deceased person to a living brain. But beyond the terminology, the procedure as such does not convince many experts, who consider that current technology does not allow an operation of this type to be satisfactory.
A head would have to be connected to all the structures of the neck : arteries, veins, respiratory tract, digestive system, bones, etc. Not to mention the nerve fibers we’d have to string together one by one. If current knowledge does not allow us to correctly join the brain and spinal cord of the same person when they are separated by a cut, for example in an accident, imagine the limitations we encounter if we want to perform a transplant.
Still, those who believe in this procedure defend it tooth and nail, and there are surgeons willing to make it work. The first “successful” transplant of this style was performed in 1970 in a primate. The surgery involved attaching the head of one monkey to the body of another. When the new head awoke, it was reportedly fully conscious and with full cranial nerve function. However, the animal only survived a couple of days.
Experiments of this type are still being carried out today, both with monkeys and rats, and even with human cadavers. This is highly controversial within the scientific community, both by those who consider it a waste of time and by those who see it as an ethical aberration. And you do you think?
References:
Lamba, N., Holsgrove, D. & Broekman, ML The history of head transplantation: a review. Neurochir Act 158, 2239–2247 (2016). https://doi.org/10.1007/s00701-016-2984-0https://www.nytimes.com/1982/06/18/us/transplant-success-reported-with-part-of-a-mouse-s-brain.htmlhttps://web.archive.org/web/20150228155418/http://www.dicotomistic.com/mind_readings_head_transplant.htmlhttps://washingtoncitypaper.com/article/206356/what-would-happen-in-a-brain-transplant-personalities-bodies-and/
