Saturday, 9 September 2017

Tricky transplants: From changing personalities to designer vaginas

Transplants are fantastical but tricky beasts. In the last week alone it was reported that a 13 year old girl who died from a brain aneurysm and donated her organs helped eight different people - a record number for a single donor. However transplants can be challenging. They can be surgically complex, like in 2011 when nine-year-old Alannah Shevenell had six of her organs replaced in one incredible operation. Alannah had a massive tumour taking over her abdomen, which necessitated the removal of her stomach, liver, spleen, small intestine, pancreas and part of her oesophagus, along with the tumour. All of the removed organs were replaced with transplanted organs and Alannah is now back in school and thriving. 

Transplants can also be emotionally complex. This was the case for a 44 year old Chinese man who received the world’s first penis transplant in 2006. He had been left with a 1cm penis stump following an accident, and in an impressive feat of surgery, surgeons gave him the penis from the cadaver of a 20-something year-old. Two weeks later they had to chop it off. Initially it appeared to have gone well, the blood supply was good and he could urinate through it, but the recipient asked for it to be removed. He couldn’t live with the idea of having a dead man’s penis.

This emotional impact of a transplant is not restricted to genitalia. A study in the Journal of Near-Death Studies interviewed 10 heart transplant recipients and their friends and family, and encountered some strange stories. There was the woman who felt her partner was a better lover since receiving a woman’s heart, and the recipient who reported feeling the impact of the car crash that killed her donor. This is a small sample size, and there is no good evidence or reason to believe a transplanted organ would affect people in this way. However this doesn’t detract from how these people feel, and it demonstrates the psychological fallout transplants can have.

Moving back to solid science, one of the major challenges when it comes to transplantation is rejection. This is when the immune system identifies the transplant as foreign tissue and launches an assault on it, causing damage that can end in the death of the organ, and therefore possibly the recipient. Rejection is more likely when the donor and recipient are a poor tissue match. This matching is largely based on a set of proteins called Human Leukocyte Antigens (HLAs) that are found on the surface of every single cell in our bodies. Our HLAs are like a barcode that identify our cells as our own. A transplanted organ is exceptionally unlikely to be a perfect match, so it’s HLAs are different from our own cells. If they are too different, the immune system successfully plays ‘spot-the-difference’ and targets the transplant for destruction. We can try and mitigate this by using drugs that suppress the immune system, but this immunosuppression puts the recipient at higher risk of developing infections.

Rejection is not a one way street - sometimes transplants attack their new bodies. For instance, bone marrow transplants effectively transplant a chunk of immune system into the new body in the form of white blood cells. These white blood cells attack their new body, in a phenomenon known as Graft Versus Host Disease (GVHD). This can result in symptoms as mild as a rash or as severe as intestinal bleeding and coma. Sometimes a touch of GVHD can actually be a good thing, like in leukaemia after chemotherapy, where the aggressive transplanted T cells can kill off some of the recipient’s remaining cancer cells.

As I said at the outset, transplants are fantastical but tricky. We’ve covered tricky, so I’d like to end on something fantastical: ‘thoes’ and designer vaginas. When someone loses their thumb, it has an understandably massive impact on the range of movements their hand can perform. One option to improve this range is to remove their big toe and put that in the place the thumb used to be, creating something called a ‘thoe’. The loss of the big toe generally has less impact on a person’s quality of life than having a missing thumb, and the thoe has the added benefit of avoiding rejection because it isn’t foreign tissue. 

Another transplant type that avoids the issue of rejection is a designer vagina. In 2014, in the Lancet, doctors reported a first - they had created vaginas grown from the vulval cells of four girls born with Mayer-Rokitansky-K├╝ster-Hauser Syndrome (MRKHS). MRKHS affects up to 1 in 1,500 female births, and leaves sufferers with a completely or partially absent vagina. By growing vulval cells on a synthetic scaffold the doctors were able to grow vaginas tailored to their recipients, and they were a remarkable success.  After an average of 6.75 years, all the girls gave their new vaginas ratings well within the normal range for lubrication, arousal and orgasm. Pretty fantastical.

These stories, along with many more, can be found in my book Immune: HowYour Body Defends and Protects You, published by Bloomsbury Sigma on September 21st 2017

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