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Islet Cell Transplantation

There will be a cure to diabetes.

There has been a lot of news about islet cell transplantation lately. The theory is based on the fact that if there are cells in the body that are able to sense glucose levels, and put out insulin appropriate to the level of the glucose (i.e., islet, or beta cells), then the diabetes will be cured. Since the individual with Type 1 diabetes doesn't have these cells, they are taken from dead donors, and transplanted into the patients. This procedure has in fact been around for many years. Over the past few years however, researchers at the University of Alberta have achieved better success rates with this procedure than other centres, freeing some long-term Type 1 diabetes patients of the need for insulin injections.

The "Edmonton Protocol" of Islet cell transplantation has uncovered two very important points. First, the chances of getting off insulin are the highest if large numbers of islet cells are given. Two or even three transplants from different donors (who are dead) are needed to supply these islet cells.

Second, a better regime of immunosupression (preventing the immune system from destroying the transplanted islet cells) treatment is needed. The University of Alberta team is using drugs that appear safer than those used in the past. In particular, no cortisone-like drugs (steroids) are used. It is becoming clear that steroids are bad for transplanted beta cells, and the cells will last longer if there is no steroid around.

Among those considered for this procedure at present are people with Type 1 diabetes who are "Hypoglycemic Unaware". In other words, these people do not feel anything when their blood sugar goes too low. Since they don't feel anything, they don't realize anything is wrong, and don’t treat the hypoglycemia. Left untreated, the hypoglycemia gets worse and worse, until the individual blacks out. This is obviously very risky, especially if the individual is driving a car at the time, or doing something where alertness is essential. These people understand their risk, and participate in the study voluntarily. The study itself is not without risks. People who receive transplants must take immunosuppressive drugs for the rest of their lives. The long-term toxic effects of these drugs are unknown, and they may increase the risk of cancer.

When a larger supply of beta cells becomes available, this work will obviously grow in importance. This day may be nearer, as researchers work to grow and keep islet (beta) cells in the lab. When cells are readily available, they might be implanted using strategies that protect them from rejection without using toxic drugs. One such strategy is to coat ("encapsulate") them with a gel that allows glucose to go through (so the cell can sense what the blood glucose level is) and insulin can go through (so the cell can put out insulin into the blood to control the glucose), but the coating prevents the immune system from seeing (and therefore attacking) the new cells, so drugs are not needed.

Other sources of beta cells may become available with new research into "Stem cells". Stem cells are "uncommitted" cells, meaning they have not differentiated into anything yet, and are capable of being any TYPE of cell. If one can guide them into becoming beta cells, then the diabetes may be curable. In theory, one will not have to depend on dead donors for stem cells - they can be taken from several parts of the body of the person with diabetes, including the bone marrow, pancreas, and other areas. Since they are the patient's own cells, no toxic drugs will be needed to prevent rejection.

Gene therapy is also advancing quickly. If genes can be implanted into cells (of the body of the individual with diabetes), that will allow those cells to sense the glucose levels, and put out appropriate amounts of insulin in response, then the diabetes will be cured as well. This may be quite possible in the future. In fact, in animal models, this has been done, using liver, or stomach cells.


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