 If your kidneys stop working, you will certainly die within a few weeks if you don't have replacement treatment. So the replacement treatment could be dialysis or it could be a transplant. A kidney transplant is the transplantation of one of an organ from a donor who may be a live donor or a deceased donor. Taking that organ and implanting it into the recipient with kidney failure. There's definite evidence that if you have a successful transplant then your survival is better than if you stayed on dialysis. So there's definite evidence that transplant improves your length of life despite the drugs that you need to take and the risks associated with that. But there's also very strong evidence that your quality of life is much better. About half of our transplants are done from friends or relatives who obviously are alive and they donate one of their kidneys to the patient that needs it. Quite commonly this is done, well very commonly it's done with children with kidney failure. One of their parents or one of their close family will donate an organ to them. It's quite difficult to accomplish an adult kidney transplant into a small baby. It needs a very high calibre team to look after the child, not just to do the surgery but to look after the child afterwards to get a successful outcome. But we commonly do this and the results are extremely good, they're really good. But for the other people that don't have a living donor they have to join a national waiting list and they wait for the suitable organ to become available. You probably heard about the shortage of organs for transplantation and that's a really serious issue. Many patients will die because they're waiting a long time for an organ and they simply can't wait that long. If the kidney fails of two main causes, one is rejection and this is when the body rejects the organ because it's not the same tissue type as they are. And that's been the huge challenge in transplantation is to understand and treat rejection. To find new treatments against rejection we need to experiment using living organs in living creatures. Although mice are much smaller than us, their biology is very similar to ours. They have the same organs and their immune systems work in a very similar way. So mice can be used as medical models to research into the process of organ rejection. This operation is classified as moderate by the Home Office on a scale from mild through moderate to severe. So the secret has been to try to identify a specific part of the rejection process and try to come up with a drug or some sort of therapy that will treat that but still allow the patient to have immunity to infection. It is impractical to transplant a mouse kidney because they are so small so researchers transplant the heart instead. The heart of one mouse is transplanted into a second mouse. Mice are fully anesthetized before the operation and given pain relievers after the operation. When I started here our success rates were about 60%. The success rates now are about 90 to 95%. There's been a huge improvement. The mortality rate is much better now. When I first started doing transplants maybe the mortality rate after a transplant was as high as 10%. It is now about 1%. So there's been massive progress. Much of it has been because we're using better anti-rejection agents. Not all of it but much of it and a lot of that development has come about by using animals. The mouse that receives the extra heart has it placed in and connected to blood vessels in the abdomen. After the operation the second heart can be felt beating under the mouse's skin. Here the second heart lives until it is rejected by the mouse immune system. The mouse remains alive while this is happening because its own heart is unharmed. Research on mice has led to much better medical treatments for rejection. These new treatments mean organ transplants last longer. A lot of transplants that we call successful eventually fail because of chronic rejection. Although the body has accepted the organ over a long period of time there is a slow rejection process going on and that will eventually damage the kidney. If we do a transplant the average time that that transplant would remain working nowadays is about 15 to 20 years. So if we transplant a child aged 2 we will be able to predict that it will fail when the child is in its 20s and will need another transplant. The next one may need to be done when the person is in their 40s. We are almost looking at multiple transplants. This in itself is a success but it is also a failure. We would like these transplants to last indefinitely. Research looking at specific targets in the immune process is so important. In that regard animal research is one of the ways forward because we are able to produce animals with specific immune variations so we can create an animal that does not have normal immunity. We can use that animal to test the rejection process and we can learn a vast amount about rejection from doing those experiments.