Transplants and Diabetes :: essays research papers

Three Toronto scientists sport developed an organtransplant procedure that could, among its manybenefits, reverse diabetes. The procedure wasdeveloped by Bernard Leibel, Julio Martin andWalter Zingg at the University of Toronto and the hospital for Sick Children. The story of their workbegan in 1978, when they delved into researchwhich had never to begin with been tried. They wantedto determine if the success rate of organtransplants would increase if the recipient wasinjected with act amounts of organ tissue priorto the transplant. The intention was to adapt therecipient to the transplanted tissue and therebyraise the threshold of rejection. In the case of thediabetes experiment, this meant injecting rats withpancreatic tissue before transplanting islets ofLangerhans, small clusters of cells scatteredthroughout the pancreas which produce insulin,glucagon, and somatostatin. In their firstexperiment, outbred Wistar rats were injectedwith increasing amounts of minced pancreas fromu nrelated donor rats for one year while a controlgroup was left untreated. Then both the treatedand control groups received injections ofapproximately 500-800 islets of Langerhans fromunrelated donors. Of the five treated animals, twobecame clinically and biochemically permanentlynormal. Six months later, Martin examined thecured rats and found intact, functioning isletssecreting all of their hormones, including insulin.None of the controls were cured. Encouraged bytheir first results, Leibel, Martin, and Zinggdecided to repeat the experiment with rats withmuch stronger immune barriers (higher levels ofrejection). Seven rats out of nine were cured. "Weset up a protocol and worked patiently with smallnumbers," says Leibel, "but the results argonindisputable." In addition to reversing diabetes,there are two other benefits to the pre-treatmentprocedure, according to the scientists. The first isthat the pancreas produces all the other hormonesof a normal pancreas, not ju st insulin. The secondbenefit is that the transplant recipient doesnt haveto take immunosuppressive drugs, which are sotoxic for diabetics. At present, diabetics whoreceive a transplanted pancreas must take such