Thursday, May 7, 2015

Road to a human head transplant

Russian surgeon Vladimir Demikhov grafted the head and forepaws of one dog on to another in 1959. Picture: Sovfoto/UIG 

AN ITALIAN surgeon’s macabre plan for the world’s first head transplant has sparked controversy in the medical community.

Scientists have called it impossible, stupid and even homicidal. But Dr Sergio Canavero is determined to make history by fusing the head of a 30-year-old with a terminal muscle-wasting disease on to a new body.

Despite its many detractors, the doctor’s grisly scheme has a strong precedent. But the litany of failures and ghastly successes should surely give our modern-day Frankenstein pause for thought.
Valery Spiridonov, left, will be the first human to have a head transplant. Source: australscope


In 1908, American physiologist Charles Guthrie sewed a second head onto a dog’s neck, linking the arteries so blood flowed first to the severed head, then to the other. The decapitated head was without oxygen for about 20 minutes, but regained small movements and reflexes, including twitching nostrils, lolling tongue and contracting pupils.


Soviet transplant pioneer Vladimir Demikhov was the next to create two-headed dogs. In the 1950s, he transferred 20 puppy heads onto adult dogs using a “blood vessel sewing machine” to minimise time without oxygen. He took the whole head and forepaws, with the oesophagus trailing out over the dog’s side. His “experiments” survived between two and 29 days, with the new heads acting like puppies and drinking milk and water. But Dr Demikhov’s notes recorded some strange outcomes, including the new head biting the ear of the other, and “tugging as if trying to separate itself from the recipient’s body.” In 1959, China also announced two successful dog head transplants.
Dr Demikhov’s two-headed dogs survived up to 29 days. Source: Corbis


American neurosurgeon Dr Robert White successfully performed a head transplant on a monkey in 1970. It was paralysed from the neck down but was able to hear, smell, taste and move its eyes. However, Dr White was unable to fuse the spinal cord and the monkey died after nine days because its immune system rejected the “foreign” head. He later wrote: “The Frankenstein legend, in which an entire human being is constructed by sewing various body parts together ... will become a clinical reality early in the 21st century”. Dr Canavero told Live Science he had dreamed of performing a head transplant since he read about Dr White when he was 15.


In 1996, William Shawlot and Richard Behringer from the University of Texas created 125 headless mice by removing a gene called Lim1 from the developing embryos, Discover Magazine reported. Only four embryos survived until birth, when they died of asphyxiation because they had neither nostrils nor mouths. A year later, headless tadpoles were created in an English laboratory, raising the possibility of using frogs to clone body parts for humans. Ethicists raised concerns over the idea of creating “grotesque” headless or brainless humans.
Dr Demikhov performing one of 20 experimental head transplants. Picture: Howard Sochurek/The LIFE Picture Collection  


In 2002, Japanese researchers experimented with grafting baby rat heads on to adults’ thighs. The team said that, if kept cool while the blood flow is stopped, a transplanted brain could develop as normal for at least three weeks, and the mouth of the head would move, as if it were trying to drink. They claimed the heads could be useful for testing brain function after a lack of blood flow, but the international community was sceptical about the benefits of the unpleasant technique, according to New Scientist.


The world’s most comprehensive face transplant was performed in 2012, on 37-year-old Richard Norris, who had been left disfigured by a gunshot wound 15 years earlier. Norris gained a new jawbone, teeth, a portion of the tongue, and soft facial tissue, and regained some function of his nerves and muscles, although doctors admitted the operation wasn’t perfect.
Richard Norris had the most extensive face transplant to date. Source: AP


In 2014, Xiao-Ping Ren and colleagues in China reported a head-swapping experiment in mice, resulting in a white mouse with a black head, and vice versa. The mice lived up to three hours after being removed from a ventilator. The body’s brain stem was kept intact, so the body could continue to control its own heartbeat and breathing.
Frankensteini's monster could be about to come to life. Source: News Limited


Now it’s Dr Canavero’s turn to try the shocking surgery on computer scientist Valery Spiridonov. The doctor plans to cool body and head so the cells do not die when deprived of oxygen. The neck of the patient will be severed and the crucial blood vessels hooked up to tubes while the spinal cord on the head and the body are severed. The head is then moved onto the body, the two ends of spinal cord fused together, and the muscles and blood supply stitched up.

The patient will then be put into a three or four-week coma to let the body heal itself while embedded electrodes stimulate the spinal cord to strengthen the new nerve connections.

Dr Canavero has already given a Ted Talk and will give a keynote address on head transplantation next month, ahead of the planned surgery in 2017.

Science-fiction has become reality, and the results could be monstrous.

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