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Scientists Cure Mice of Diabetes Using Cells Grown Inside Rats (qz.com)
In a process that could transform organ transplantation, scientists in Japan and the U.S. have reportedly cured mice of diabetes by transplanting mouse cells grown in rats. The study has been published in the journal Nature. Quartz reports: To achieve this feat, researchers injected mouse pluripotent stem cells into a rat embryo. As the name suggests, these pluripotent stem cells are able to transform themselves into all types of cells. The mouse cells intermingled with rat cells, and created a chimera whose organs and tissues were almost all created from a mix of mouse and rat cells. Crucially, however, they had modified the rat to not produce pancreatic cells. They achieved this by knocking out a gene called Pdx1. The upshot was that the pancreas in the chimera was almost completely made of mouse cells. When the rat-mouse chimeras became adults, the researchers removed the animals' pancreases and from them, isolated endocrine islets, which contain B-cells that produce insulin. The B-cells were then transplanted to diabetic mice that had lost all their native B-cells. The mice that received the transplant were put on mild immunosuppressant drugs. However, the scientists found they only needed to administer the drugs for five days after transplantation. Surprisingly, the few rat cells that came along during the transplant (mostly in the blood vessels in the islets) had been destroyed and replaced by the mouse's own cells. The B-cells in mice that got the transplants functioned just as they would in a healthy mouse for more than a year, which was the complete observation period. These lab mice only live for two to three years, which makes a one-year observation fairly long. The research opens up the door for growing human organs inside, say, a pig, using the patient's own stem cells and then transplanting the organ when it's mature and ready.
This is great as it works to solve the Islet cell production problem, however it by itself is not a cure.
There are already several drugs that are known to cause insulin producing beta cells to grow in the human pancreas, however the problem that this does not address is how to stop the immune system in the type 1 diabetes (autoimmune) from just destroying all of the new islets from this process.
There have been trials of procedures to limit, suppress or re-educate the immune system to halt the autoimmunity with varying degrees of success (usually just making it so that the autoimmune attack on the pancreas does not get any worse but does not get any better either in the best of cases) Unless you can do both, halting the autoimmunity and replacing the beta cell mass this will not be a practical cure for type 1 diabetes. It is simply an alternative piece of the puzzles for the part about how to replace islet cells once we are able to stop them from being destroyed by the patient's autoimmune condition. We are not very far along on the understanding of the cause of autoimmunity. Some studies say that it is caused by bacteria, some say it is caused by genetics, some say it is caused by heavy metal poisoning some say it is caused by viruses some say it is caused by radiation. Until we can figure out why autoimmunity occurs in a specific patient and reverse that autoimmunity, implanting replacement beta cells is an exercise in futility.