Monday, March 13, 2017

Head transplant 5

Imagine you’re suffering from an irreversible genetic disorder that eats away at your muscles and snuffs out your motor neurons. You’ve watched yourself shrink and implode until you’re confined to a wheelchair. You know that one day soon this disease will kill you, yet you still have dreams to realize. You’ll do whatever it takes to keep going.

Then, you hear about an Italian neurosurgeon, Sergio Canavero. He thinks the time has come to push the frontiers of organ transfer beyond just kidneys, livers, hands and uteruses. It’s time to transplant the human head to a new body. This will extend your brain’s life. Even better, according to Canavero, if you’re attached to a young body your brain also will be rejuvenated.

So you read about what’s involved. Your body will be cooled to about 50 degrees F, your spinal cord severed just above the collarbone, and your head, along with your trachea and esophagus, will be removed and reattached to the healthy body of a brain-dead patient (whose head has been excised so yours can take its place). Then, surgeons will apply polyethylene glycol, a chemical fusogen that preserves and joins nerve cell membranes, in order to bridge the two spinal cords. This is not so much a head transplant as a whole-body transplant. It will take 80 surgeons and about $10 million to see this through. If all goes as planned, Canavero believes you will walk again. And he is looking for a willing human subject.

Are you in?

This was the question facing Valery Spiridonov, a 31-year-old wheelchair-bound Russian man who suffers from Werdnig-Hoffmann disease, a usually fatal genetic disorder. He is eager for his head to find a new home, encouraged perhaps by Canavero’s deadline for surgery (December 2017) and the Italian surgeon’s optimism (“The chances of this working are 90 percent,” he says). Or is it that Canavero has named his project HEAVEN, which stands for “head anastomosis venture”? Or his carnival-barker enthusiasm? (See his TED talk on HEAVEN, which begins, “Are you sitting tight? I’m about to give you one hell of a ride!”)

As a kidney transplant recipient, I would not be alive without medical innovation. I don’t wring my hands for the sake of ethical handwringing or because of some ill-defined “yuck factor.” Still, Canavero’s torrent of enthusiasm needs to be contained.

It is not clear, for example, that Spiridonov knows he’s a subject in a risky experiment lacking any long-term empirical studies to support it. Canavero says success is 90 percent guaranteed, which is terribly misleading, making informed consent impossible. Has Canavero told Spiridonov that rejection and infection are major obstacles in transplant surgery (the first uterus transplant in the U.S. failed because of a yeast infection); that a human spinal cord has never been successfully reattached; that, while he is now mobile and has the use of his arms, Spiridonov may end up on a respirator with no motor function whatsoever; that Canavero’s studies on cats, rats and mice, are only apparently successful, have not been replicated by other laboratories and that these animals have markedly different spinal cord circuitry than humans?

But let’s assume surgery happens, and it’s a wild success: Spridonov is a new man, a new kind of human being. What has been achieved? A life has been saved, a man who never walked will take his first steps and Canavero and his team are famous. But what is the likelihood this will be routine surgery one day? Where will the donor bodies come from? Will people refuse to sign their donor cards now that their entire bodies are donatable? Will they accept the burial of only their heads? And at a cost of millions, will this surgery help the wealthy live longer on top of less fortunate bodies?

And then there is the pesky mind-body problem. I interviewed Dr. Robert White a few years before he died. White was a Harvard-educated American neurosurgeon who, in 1970, for the first time transferred a monkey head onto the headless trunk of another monkey’s body. The new monkey survived a few hours, paralyzed from the neck down and on a respirator (what many of Calavero’s critics say is a best-case scenario for Spiridonov). I asked White if the brain is all that matters. Aren’t we embodied beings? He sighed as though he’d heard that question too many times before. “Our essence is between our ears. The body is just life support,” he said.

Whether you think moving your head from one body to another in a cephalic shell game is worth it depends in large part on whether or not you agree with White.

1 comment:

  1. Last year, Dr. Sergio Canavero created quite the ruckus (to put it mildly) when he vowed to be the first person to transplant a human head onto a deceased donor’s body. Yes, he is planning on attempting the world’s first human head transplant (or body transplant, depending on how you look at it).

    In fact, it has been about a year since his initial proclamation, and the Italian neurosurgeon still stands firm on his declaration, despite claims from other experts that it is nothing but a PR Stunt (at best) or a hoax. Some have even hypothesized it’s all just a plot meant to promote Metal Gear Solid.

    This last claim is due to the doctor’s uncanny resemblance to one of the game’s main characters (it must be noted that there is scant evidence to actually support this hypothesis beyond this).

    Honestly, it has been a story full of drama and sensationalist publicity. This whole mess went so far that talks of lawsuits were flying all over the place. But Canavero stands firm, insisting that the attempt must be made at some point.

    So, why not now? “Of course there will be ideas that crater. The history of mankind is trial and error. But we have to be dreamers. If you don’t dream, you’re not going anywhere. You might call me a bit crazy. A kook. I am! You have to be if you want to change everything,” he said in an interview with The Guardian.

    Canavero continued by asserting that such daring enterprises are part and parcel of scientific exploration. Society’s job, according to him, has always been “to tease apart the kooks from the super-kooks. And maybe you can only know that after the caper.”

    At the annual meeting of the American Academy of Neurological and Orthopaedic Surgeons last year, Canavero tried to recruit US surgeons to join his head transplant team. And now, it seems that he is actually moving forward with this work.

    He says he has assembled a team of surgeons from China, South Korea, and Russia. All they are waiting for is approval and, well, money.

    His collaborator, Dr Xiaoping Ren of China’s Harbin Medical University, claims that he was able to successfully transplant the head of a monkey onto another monkey in January, but that it had to be euthanized for “ethical reasons” 20 hours after. Yet notably, the spinal cord wasn’t actually attached (which raises significant questions about the viability of such an operation on a human).

    Although a lot of attention centered on Russian volunteer Valery Spiridonov, who suffers from a Werdnig-Hoffman disease, Canavero now clarifies that the first patient to undergo the head transplant will be a Chinese patient.“

    We’re looking at a date around Christmas 2017 to perform the transplant in China. The Chinese team has already experimented on human cadavers to hone the technology,” Dr. Canavero revealed.

    Many argue (a majority of scientists working in this field) that a head transplant is currently impossible, despite advancements dealing with spinal cord problems. Recently, we covered how scientists were able to regenerate spinal cord axons, but even that procedure takes a lot of time, and it is a very recent development…one that is probably not a part of Canavero’s plan.

    Most say that the surgery will end in death. Others note that it may actually result in something far worse than death, as the difference in brain chemistry could overwhelm the patient and cause a level of insanity never before seen.

    Canavero calls the procedure the “head anastomosis venture,” code-named “HEAVEN.” But is it? It may lead to new knowledge and information, but as other experts note, it will likely also lead to the patient’s death and (very possibly) no information that we couldn’t obtain through working on cadavers.