September 20, 2020

The woman unable to feel pain | Science

The woman unable to feel pain | Science


The Scottish Highlands are full of legends of fairies, werewolves and mysterious creatures under Loch Ness, but this story is real. At the Raigmore Hospital in Inverness, the capital of the region, they still remember the day when a 66-year-old woman came through the door to remove a bone from her wrist at the base of her thumb because of osteoarthritis. "You do not have to anesthetize me, because I do not feel the pain," the lady told the anesthetist with a smile. Devjit Srivastava. He, unbelieving, continued with the usual protocol and slept his patient, but he remained pensive. And if it was true?

And it was. An international team of researchers today presents the case of Jo Cameron, a woman "witty, happy, optimistic" and "insensitivity to pain", characteristics produced, according to scientists, by two mutations in its genome that make it almost the same. double endogenous cannabinoids in your brain. "It's a lot. This makes me ridiculously happy and it is annoying to be with me. People like to be sad, "Cameron jokes over the phone.

"I often burn in the kitchen and I do not know until it smells of burned meat," explains Jo Cameron

After that operation that had to be painful, the anesthetist Srivastava set out to be attentive to that woman. He observed that he was given a single dose of paracetamol, "possibly by routine", and Cameron did not ask for more, he recalls still amazed. The doctor tried to pinch him and as if nothing. The questions began.

A year earlier, Cameron had undergone another surgery to replace his hip with a prosthesis. Nor felt pain, he said. "I often burn in the kitchen and I do not know until it smells of burned meat. I have many scars on my body, "he explains over the phone. "It's not a good thing. This has its advantages and disadvantages. The pain warns you that something bad is happening. And I do not know. "

Srivastava alerted other colleagues and the unusual case came to institutions such as the universities of Oxford, Cambridge and California. His study, published today in the specialized magazine British Journal of Anesthesia, points to the alleged causes of Jo Cameron's painless happiness. Each human cell works thanks to an instruction manual of 3,000 million letters. A paragraph in that tiny book controls the production of FAAH, an enzyme that degrades anandamide, a chemical compound that in turn allows natural communication between neurons in the brain. The name anandamide derives from the sensation it produces. Ananda, in Sanskrit, means happiness. It is considered an endogenous cannabinoid because its effects are similar to those of the cannabis plant, marijuana.

Jo Cameron eats ultra-sharp peppers in the consultation of the anesthetist Devjit Srivastava, in Inverness (Scotland).
Jo Cameron eats ultra-sharp peppers in the consultation of the anesthetist Devjit Srivastava, in Inverness (Scotland).

The researchers believe that Cameron inherited two mutations in the area of ​​the human genome that has instructions to eliminate anandamide. "We believe that there is no problem in the transmission of pain, but rather the abundance of anandamide […] in the brain due to its genetic defects makes it not feel the pain, "summarizes Srivastava.

The anesthetist remembers that, for example before a burn, the body sends electrical signals through the nerves to the spinal cord, which processes that message and transfers it to the brain. "The signals that reach the brain form the experience of pain, but this sensation depends on genetics, emotional state, hormonal status, expectations, previous experiences and other factors, "says Srivastava. The natural overdose of anandamide in Cameron's head would dilute that painful message in the brain.

"Our ultimate goal is to find better treatments for millions of people with chronic pain," says researcher James Cox.

"It's an amazing story. I have the privilege of being able to see the structure of nature ", celebrates the anesthetist who happened to run into the case in a hospital in the Highlands of Scotland. A photo shows Srivastava and Cameron together in the consultation. She appears chewing hot peppers of the Scotch Bonnet variety, known in some countries as fireballs. "Mrs. Jo can eat them without feeling any burning sensation," says the doctor with astonishment.

"Our ultimate goal is to find better treatments for millions of people with chronic pain," he says. James Cox, molecular biologist at University College London and co-director of the study. His team is now working on the genetic editing of human cells in the laboratory to try to replicate Jo Cameron's mutations and better understand their effects.

Researchers remember that the path to new treatments will not be easy. Already in 2001, US scientists showed that mice genetically modified to not generate the FAAH enzyme had high amounts of anandamide, the substance linked to happiness. However, recent clinical trials with FAAH inhibitor compounds have failed. In 2016, one of these experiments ended in France with five serious people, one of them in brain death.

In spite of everything, Jo Cameron looks forward to the future. "There are many people who feel a lot of pain. I would be very happy if my genetics helps to find a natural way to reduce their suffering, "he confides. It could not be otherwise. Cameron carries optimism in the brain.

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