I am sure you know that the first hand transplant in England took place last week. A hand was transplanted onto Mark Cahill. Metal plates were installed to join the bones in the arm with the donor bones in the hand; blood vessels were joined and nerves connected. Mr Cahill can move his fingers but has no sense of touch. It is not known if he will develop sensation in his hand and it will be a major advance if he does. The first recipient of a hand transplant had his hand removed because he said it was like a dead man’s hand with no feeling and he felt clinically detached from it.
Transplanting a hand involved a difficult ethical decision as the new hand was undertaken to improve the quality of Mr Cahill’s life and was not a ‘life saving’ operation like a heart transplant. Mr Cahill will need to take life long immune suppressing medication to prevent rejection which will make him more susceptible to infections and slightly increase the risk of developing cancers.
Pluripotent stem cells have the capacity to differentiate into different forms of tissue and so one day it may be possible to take cells from a person and ‘unwind them’ to form pluripotent stem cells. [see previous post – 9/10/12 Britain’s John Gurdon wins the Nobel Prize for science for work on stem cells]These cells then can be used to form new body parts. Because they are derived from our own cells they are not recognised as foreign and are not attacked by our immune system and it is not necessary to take immunosuppressive drugs. We already use stem cells for retinal transplants for damaged eyes. A year ago a patient in Sweden received the world’s first trachea produced from stem cells. Hearts have been produced by stripping a ‘dead’ heart of tissue, leaving a collagen frame. Stem cells are then applied to this collagen frame. The stem cells seem to recognise the structure and know what cells to differentiate into – muscle, nerve etc. (This may sound amazing but it must be remembered that a few stem cells in an embryo seem to have the knowledge to differentiate in the complex interconnecting organs that form a baby.) The hearts produced even started beating but only weakly. An arm would be even harder to produce as it consists of many very different types of tissue such as bone, blood vessels nerves and skin.
An alternative would be to have a prosthetic arm. Prosthetics are getting better and better and may one day be better than the real thing! – see the story of this boy who has an artificial leg and arm . http://www.bbc.co.uk/news/health-17251690