It is infinitely better to transplant a heart than to bury it so it can be devoured by worms.
— Dr. Christiaan Barnard
An organ transplant is the surgical procedure where an organ of the body is removed and placed elsewhere as a functional attachment; you may or may not believe this, but the first successful transplant in human history was completed in 300 AD. Ss. Cosmas and Damian were twin brothers, physician-surgeons, and Christian martyrs. They lived in Ęgea, the main port of Cilica, where they healed the sick and did not charge, even a penny, in exchange for their service. For this, they were nicknamed anargyroi, or, The Silverless. The story goes that they transplanted the leg from one person to another – something that we are having trouble to complete even today. They are often depicted in paintings having just completed this feat of surgery; the brothers dressed in long robes holding surgical instruments (and occasionally cradling the recently amputated limb) look upon their patient, a Roman called Justinian, who is in turn looking at his legs in amazement. For where once before he had a diseased, ulcered leg, he now had a brand new limb... He knew it was a new limb because he was white, and his new leg was black; the donor was a recently deceased Ethiopian Moor. On the issue of whether or not the Ethiopian had consented to have his leg used in such a way, history remains silent.
Oh, and did I mention that they actually completed this surgical procedure several decades after they died? I didn't? All over Europe and Asia Minor, the two brothers are regarded as the patron saints of medicine and pharmacy, and their feast day for the Roman Catholic Calendar of Saints is 26th September. It used to be the 27th September, but they got bumped back a day for no discernable reason. Happens all the time, I'm sure.
Actually, I'm lying about Cosmas and Damian having dibs on the first ever organ transplant – it's just that they had the best story; remember kids, when writing up something that's potentially boring in the extreme, be sure to add small points of interest as you go to keep the bastards reading. Now, where was I? Oh, yes. Before them, 'them' being Cosmas and Damian, there was two others that claim this achievement. One is an ancient Chinese physician from the 6th century BC, Bian Que. He claimed to have transplanted the hearts of two warriors in an attempt to balance out their spirits and will. Full marks for grandiosity, but he scores low for there being no actual shred of evidence for this claim. However, the other claimant is a gentleman who went by the name of Sushruta, and he may actually, genuinely, have completed the first ever successful organ transplant; thoughts of the time that he lived vary, but the general consensus was that he lived around the 2nd century BC. Texts still exist that are credited to him on medicine and surgical techniques, as well as diagrams of surgical instruments that he used. Back in the day, one punishment for thievery was the removal of the criminal's nose so that all would know of their crime. It is said that Sushruta performed skin transplants for these individuals to help these wounds heal, certainly a feat that is plausible.
These ancient healers may have blazed the trail, but they were (eventually, 1,500 years later) followed by many others.
Types of transplants
- Autograft: transplantation of tissue from one part of the body to another in the same individual
- Isograft: transfer of an organ or tissue between two individuals whose genetics are identical, i.e. identical twins
- Allograft: transplant of an organ or tissue between two individuals of the same species; this is the most common type of transplant performed in humans
- Xenograft: transplant of tissue or organs between disimilar species, e.g. porcine heart valves to human hearts
- Orthotopic graft: donor organ is transplanted to the same site as the recipients diseased one
- Heterotopic graft: donor organ is inserted at a different site to the diseased organ
- Artificial (hybrid) organ implantation: transplant of bio-artificial organs – a combination of biomaterials and living cells; so far this is an experimental technique.
So, for example, a kidney transplant is a heterotopic allograft – the new kidney from another human being is attached to the abdominal aorta, and the diseased kidneys are not removed. A coronary artery bypass graft is a heterotopic autograft – a replacement artery or vein is removed from elsewhere in the body and used to replace the diseased arteries of the heart. A liver transplant is orthotopic allograft – the new portion of liver is placed in the same place as the diseased liver. Get the idea?
The history of transplants
The concept of performing the transplant of one body part to another place on the body, or to another individual completely, has been around for centuries; the first documented successful skin transplants were performed in the 16th century by an Italian surgeon, Gaspare Tagliacozzi. The actual term 'transplant' was first coined by John Hunter, a very prominent surgeon of the 18th century, whose anatomical specimens can still be viewed in the Hunterian Museum at the Royal College of Surgeons in London. Then in 1902, Eduard Zirm and Alexis Carrel performed the first transplant of human corneas; their work continued with their research into the development of techniques of forming anastamoses, where two severed vessels are stitched together to once more provide a patent blood circulation to a severed limb.
The first transplant of an organ that allowed the patient long-term survival was that of a kidney in 1950 by Richard Lawler, and in 1963, the first liver transplant was performed by Thomas Starzl. In 1967, one of the most important developments in transplant technology occurred: Christiaan Barnard performed the first heart transplant. From here on in, transplant technology has improved at a considerable rate; in 1981, the first heart-lung transplant was performed. We now are able to transplant bowel, pancreases, limbs, and faces. From here on in, it can only get better, with more long-term successes achieved.
The future is bright; current research is moving in the direction of improving the success rate of transplantations with new improved immunological suppression agents; the more frequent use of xenografts to provide an increased availability of organs; and the development and utilisation of cellular/biomechanical approaches to providing patient immunological-specific graft organs.
Sources of transplant organs
Organs can be sourced from both the living and the dead, the key consideration being whether the donor is a 'match' to the recipient. The preference is from a donor who has died, for purely practical purposes; they're not going to be putting their life at risk by donating their organs. However, the organ transplant waiting lists are so long that, for the most part, if a willing live donor is found, and they (with appropriate counselling and information) are fit to donate, then most transplant surgeons are happy to proceed with the procedure. Of course, this has lead to a black market in organs, where seriously ill patients are willing to buy organs from live donors, and the live donor is desperate enough to take the money at considerable risk to themselves. In both the UK and the US, selling organs for financial profit is illegal, but the same is not true of elsewhere. For instance, in Iran it is legal to sell one of your kidneys, with a going rate of $2000 - $4000 a piece. The ethics of this are a little murky, but here's something that you should consider: there are no kidney transplant waiting lists in Iran.
The rest of the world relies on altruism and cadavers for their organ waiting lists. One of the side effects of increased health and safety considerations in all areas of our lives is that the number of potential cadaveric donors has decreased; for a cadaver to be a suitable donor they need to have died in a state of health, thus accident victims were a prime source. They also need to be placed on a ventilator as soon as possible after brain death has occurred on order to keep the organs alive. On occasion, organs are taken from donors who weren't put on a ventilator (donated after cardiac death (DCD) donors), but these transplants tend not to be as successful as from a beating heart donor.
With living donors, it is often a family member of the patient as they are more likely to be a match, and they also get the emotional pay-off for the risk that they take by saving the life of a family member. Paired-exchange is an option where there is no family match; a willing family member of patient A will donate to patient B, and in turn, a willing member of patient B's family will donate to patient A. Occasionally people will willingly donate to strangers as an act of philanthropy, but this is rare. One more source is from domino transplantation, which is mostly commonly performed in cystic fibrosis patients. The cf patient receives a complete heart and lung transplant, because this is an easier and more successful operation to perform than just a lung transplant. The cf patient's (usually) healthy heart is then transplanted into someone on the heart transplant waiting list.
Organ matching
For a transplant to be successful, the organ must be of a close enough match that the recipient's immune system will not reject and attack the transplanted organ. The first hurdle to overcome is the ABO blood group types; transplanting an organ from an AB-type donor into an A-type recipient will result in an acute rejection of the organ. As with blood donations, the rule of thumb is that group O patients are universal donors (i.e., can give to anyone) and group AB patients are universal recipients (i.e., can receive from anyone). The suitability of an organ is then further determined by histocompatibility antigens, the genes for which can be found in the major histocompatibility complex (MHC) located on chromosome 6. All very complicated and boring, at least to myself who regards immunology with the kind of distrust and loathing exhibited by people who aren't quite as clever as they think they are when confronted by something that they Don't Really Understand All That Well. To people who Do Understand It Well, the important things to consider are the human leucocyte antigens (HLA) that are coded for within the MHC. There are several types of HLA, there are even more various sub-types of each HLA type. The short of the matter is that the more matches you get when looking at the sub-types, the more likely it is that the graft won't be rejected by the recipient, leading to increased survival time.
However, it isn't enough though that the patient and donor are a good match; the patient will also have to take a life-long drug cocktail with the aim of suppressing their immune system in order to discourage it from rejecting the organ. It's a difficult balance to achieve: on the one hand you want the graft to survive and be happy; on the other, if you suppress the immune system too strongly, the patient will be unable to fight off infection and prevent the development of malignant cancer cells (cancer rates are significantly higher in transplant populations.) There is further complication in that many of the drugs used have rather nasty side-effects which in turn may decrease the life of the graft. For instance, ciclosporin is a very effective immunosuppressant; it's also nephrotoxic and hepatotoxic, i.e., it kills kidney and liver cells. Not all that ideal in kidney and liver transplant patients, but needs must when the devil drives.