The First Human Head Transplant: Is it Really Possible?

hen Dr. Sergio Canavero announced that he would perform the first human head transplant in 2017, the public was greatly intrigued while the science world remained skeptical. This article aims to examine the science behind the head transplant and asks if such a feat is realistically possible at this point in time. It also explores the ethics behind disclosing a scientific breakthrough that could theoretically change society, without ever having published any peer reviewed scientific literature to support the claim, which is exactly what Dr. Canavero has done. This leaves many scientific professionals and skeptical members of the public wondering if this is a pseudoscientific publicity stunt that has gone so far that it could potentially kill or torture its first patient in the name of attempting to make history. Most of all, it is important to not take science seriously when that science has not actually been rigorously tested. That is what has happened in the case of the world's first head transplant, and until more research surfaces, this kind of “science” should be considered PR and pseudoscience. This story illustrates a good way to spot it.

Dr. Canavero, who has not produced significant original research to support his claim, sites two main studies that have been performed in the past as evidence that his human head transplant is possible. Neuroscientist Dr. Jerry Silver, who was one of the scientists involved in the 1970 head transplant of a Rheys monkey says that neither of these studies come close to proving that a human head transplant could succeed.

In his paper published in the June issue of the open source journal Surgical Neurology International, Dr. Canavero states that the 1970 monkey experiment was a successful head transplant stating that, "The monkey lived 8 days and was, by all accounts, normal, having suffered no complications." This argument is a major pillar in his claims that a human head transplant is possible with modern technology.

In fact, the monkey was unable to take food and was completely paralyzed below the transplant point. Dr. Silver, who was actually there, states, "I remember that the head would wake up, the facial expressions looked like terrible pain and confusion and anxiety in the animal. The head will stay alive, but not very long...It was just awful. I don't think it should ever be done again (Elliot, 2014)."

According to Dr. Canavero, "The greatest technical hurdle to such an endeavor is of course the reconnection of the donor (D)'s and recipients (R)'s spinal cords. It is my contention that this technology only now exists for such linkage (O'Halin, 2015)."

However, is there existing scientific research that supports that a spinal chord could refuse effectively? Past research that examines this claim is the other main pillar of his argument.

There have been a few studies to date that have addressed spinal chord rejuvenation. According to Dr. Silver, these controlled experiments are, "lightyears away" from something that can be compared to a successful human head transplant. Here are some of the specific scientific points that need to be considered in order for successful regeneration to take place (Elliot, 2013).

Glial scars are a special kind of scar tissue that begins to form almost immediately when spinal chord tissue is severed. This serves as a protection so that further damage does not occur, but it also produces chemicals that keep the tissue from reforming. This would present an immediate concern during the procedure, as there would have to be some way to prevent the scars from instantly forming. Dr. Cavanero doesn't address glial scars at any point in his paper, so it isn't clear how that would be dealt with (Ó halin, 2015).

One of the main elements to a successful head transplant is the use of PEG, polyethylene glycol. PEG essentially acts like a glue for the spinal chord, and there has been success using it in rats. A 2014 study entitled, "Long-lasting significant functional improvement in chronic severe spinal cord injury following scar resection and polyethylene glycol implantation" showed that rats with severed spinal chords did experience significant regeneration. In the study the rat's spinal chords were severed in the dorsal thorasic region (lower middle back). The injury was allowed to heal for 5 weeks and was then cleanly re-severed and PEG was applied.The abstract reports, "long-lasting significant locomotor improvement over a period of 8months." and concludes that, "scar resection and subsequent implantation of PEG into the generated cavity leads to tissue recovery, axon regeneration, myelination and functional improvement that have not been achieved before in severe chronic SCI.(Estrada, 2014)."

That information is promising, and clearly there was regeneration after the spine was severed thanks to PEG, which got past the glial scar issue. However, this case is different from a human head transplant, because the head obviously would go onto a different body. In this case, the spine was severed and immediately glued together again. In the case of a head transplant, the head would be completely separate and sitting in a cooled environment for some time before it was attached. For the rats in this experiment, the spine was severed below the middle back, and so they were able to breathe and regulate their basic body functions. This would not be the case with a head transplant, and if anything was connected improperly the patient would be stuck on life support for the rest of their life (Elliot, 2013).

Experts from different fields have different additional concerns. What about reconnecting a very complicated vascular system? Another major worry is that of organ rejection. People with any foreign body part need to be on intensive and potentially dangerous medication for the rest of their lives. The world's first hand transplant wasn't successful and was rejected in time; a rotting and atrophied shadow of its once healthy self. How intense will organ rejection be when an entire body is replaced? Experts worry that it would be both maddening and deadly for the patient. Dr. Canavero doesn't really have an answer for these questions, and invites other medical professionals to get involved. While attempting to recruit fellow doctors at the annual meeting of the American Academy of Neurological and Orthopedic Surgeons Cavanero's speech heavily relied on inspirational messages that condoned the risky nature of the procedure. As he assured high pay from American billionaires he made statements like, “We must go to the moon to test who we are, to test our skills, to test our confidence, to see what kind of men we are!”(Thielman, 2015)

From a scientific perspective a lot of this reeks more of rhetoric than valid research. There are glimmers of hope that one day we will be able to restore severed spinal tissue. As we all know, at this point we are not able do this. Those with traumatic spinal injuries are paralyzed for life in most cases. Since we are not even able to perform a reliable procedure to enable paralysis victims to walk again with their own body, it is truly a leap to imagine that next year we will be successfully transplanting heads. All of the science points to the fact that it is an unrealistic procedure for 2017. We can establish that the scientific data to support the feasibility of the procedure is lacking at best, but we live in a world where great PR usually beats hard science. How are Canavero's claims effecting society and the lives of real people?

Despite the fact that most doctors agree that the procedure will most likely kill the patient, and that said patient would experience "something much worse than death" in the unlikely event of survival, Dr. Canavero has already scheduled the first human head transplant to go ahead with Valery Spiridonov, a 30-year-old computer scientist from Vladimir, Russia. it has been scheduled to take place in China next year (Griffin 2015). The team of surgeons has already been selected and at this point in time it seems like the procedure will go ahead. According to Canavero, the procedure will take around 36 hours and will require around 100 surgeons working around the clock. Valery will stay in a coma for about three weeks after the procedure, and the doctor expects to see him walking within a year. Canavero has received many e mails from people around the world asking for the procedure, and he will first reserve it for those with muscular wasting diseases, like Valery (Whiteman, 2015). The procedure is estimated to cost 13 million, and Valery has asked Mark Zuckerberg to foot the bill. Objectively examine the tantalizing details of the tale, and there's no wonder that the story is creating a press storm. However, it's considered low brow in the scientific community to release this kind of break through to the public, without actually having the data to back it up. So why would Spiridonov put himself in the position of such risk?

"You have to understand that I don't really have many choices...If I don't try this chance my fate will be very sad. With every year my state is getting worse (Thielman, 2015)."

The procedure is unethical in that it is clearly risking a person's life and doesn't have the scientific research that it needs to be deemed safe and effective. However, if a patient is living in so much pain that they do not see their life as valuable and worth living, is it ethical to risk that life? This is not a question that this article aims to answer, but it is one that truly needs to be asked by the public and the medical community. A similar question was raised about 10 years ago as face transplants began to be performed. While many experts thought that they were impossible at the time, it turned out that they have been a great thing for people who truly needed them, and that they are effective. However, we are talking about an entirely different head on an entirely separate body, and so an analogy between the procedures is limited.

The first human head transplant has become a global media sensation. However, at this point in time, it is not much more than that. The existing science doesn't add up, and Canavera doesn't have much of his own research to back up his claims. What kind of damage can be inflicted when this kind of breakthrough is announced without having real published material to back it up? As the evidence stands, there is a very good chance that the operation will end in tragedy, and that the public will be left with a feeling of disappointment and alienation towards a scientific institution that has promised so much and delivered so little. However, if the operation is indeed a success, then of course it will change the course of history. This kind of glamorous ideal is probably what is so appealing about it, and why it attracts so much attention. Later this year, Dr. Canavera says that he will publish his own research, which he says will back up his claim. Until then, it is important that we remain skeptical and remember that at this point in time, the doctor is backed by far more alleged "American billionaires" than he is by solid scientific data.

Sources:

Elliot, Danielle. "Human Head Transplant Is "bad Science," Says Neuroscientist."CBS News; Science. N.p., July 2013.

Estrada, V. "Long-lasting Significant Functional Improvement in Chronic Severe Spinal Cord Injury following Scar Resection and Polyethylene Glycol Implantation." National Center for Biotechnology Information. U.S. National Library of Medicine, 2014.

Lee-Kubli, Ca. "ResultInduced Pluripotent Stem Cell-derived Neural Stem Cell Therapies for Spinal Cord Injury.

Filters."National Center for Biotechnology Information. U.S. National Library of Medicine, Jan. 2015.

O'halin, Daryn. "Why Human Head Transplants Are Still a Long Way from Becoming a Reality."The Conversation. N.p., Aug. 2015. Web.

Petruzzo, P., and J. Dubernard. "The International Registry on Hand and Composite Tissue Allotransplantation."National Center for Biotechnology Information. U.S. National Library of Medicine, 2015.

Ren, XP, Y. Song, and YJ Ye. "Allogeneic Head and Body Reconstruction: Mouse Model."National Center for Biotechnology Information. U.S. National Library of Medicine, Dec. 2014.

Thielman, Sam. "Surgeon Promising First Human Head Transplant Makes Pitch to US Doctors." The Guardian. Guardian News and Media, 13 June 2015.

Whiteman, Honor. "Transplants / Organ Donations Neurology / Neuroscience Surgery Medical Innovation 30-year-old Russian Man Volunteers for World's First Human Head Transplant." Medical News Today. MediLexicon International, Oct. 2015.