Since the discovery of insulin, there have been important advances in the understanding both type 1 diabetes and type 2 diabetes. But only some of these advances have led to major changes in the lives of those with the disease. Media reports of breakthroughs often offer unrealistic hope of change to children with diabetes and their parents.
The reality is that advances in research usually take many years. Research must go through certain stages of testing, first in test-tubes, then in animals, and finally in people. Sometimes, research that at first seems successful doesn’t work out in the long run. This can be disappointing, but it often improves our understanding of diabetes. So read the newspaper or watch the news with a critical eye. Get as much information as you can from health care professionals, diabetes journals, and other sources before forming an opinion.
Some people with diabetes, as well as those with other conditions, are quite cynical. They believe that the research and medical communities have the ability to cure their disease, but that there is too much profit to be made from not providing a cure. Nothing could be further from the truth. Both type 1 diabetes and type 2 diabetes pose a huge public health burden. It has been suggested that over 10% of all health care costs are related in some way to diabetes. A cure is in everyone’s best interests. However, a cure may be harder to pin down than the optimist or the media would have us believe.
Diabetes research is being carried out in a number of areas, including:
- causes of diabetes
- ways to prevent diabetes
- ways to prevent the disease from progressing once it has started
- ways to make treatment easier
Researching the cause of diabetes
Over the past 20 years there have been huge advances in our understanding of the genetic aspects of type 1 diabetes. Still, pieces of the puzzle remain to be found.
The genetic link
There are a number of genes that make a person more likely to develop type 1 diabetes. The most important ones appear to lie in the HLA (histocompatibility locus antigen or "tissue typing") region of chromosome 6. This region contains genes that control the way the body responds to foreign materials -- the immune response. Examples of foreign materials are viruses, bacteria, and toxins. In people who are more likely to develop diabetes, these genes appear to be somewhat impaired.
In this region of chromosome 6, different genes have different effects on making a person more or less likely to develop diabetes. Some actually give resistance to diabetes! Could this resistance be turned into a gene therapy that could change these damaged genes and protect against diabetes? This is an important research question, but the answer is still a long way off.
The environmental link
There has been a lot of research looking at things in the environment that may "wake up" a genetic tendency to diabetes. This research has looked at on viruses, environmental toxins, and food products, such as cow’s milk protein early in life. So far, there is no consistent result and there isn’t a single trigger that causes diabetes to develop. Researchers hope to find a virus or other germ that causes damage to the pancreas. This way they can work on developing a vaccine against it. This could possibly prevent diabetes. Avoiding certain toxins could have a similar effect. Researchers are now testing these ideas in both animals and humans.
Preventing the immunological response
Once diabetes starts to develop, a series of events occur. These events are now well understood and are being studied in greater detail. The immune system and environmental problems lead to an inflammatory response (insulitis) in the islet cells where insulin is made. Antibodies to some of the proteins in the islets appear in the blood. Detecting these antibodies allows us to determine who may be at high risk for developing diabetes.
Most of the studies are done on close relatives -- parents, children, and siblings -- of people with diabetes, because the risk to family members is much higher than in the general population. This is what you would expect in any disorder with a genetic link.
The problem is that diabetes in family members accounts for only 5% to 10% of all new cases of type 1 diabetes. Studies in the general population have been much more difficult to perform. They may not be as useful for making predictions as studies in close relatives.
There have been some useful studies in animals, such as certain breeds of mice and rats that suddenly develop an autoimmune type of diabetes very similar to that seen in people. These studies have shown that diabetes can be prevented by exposing the animals to a number of medicines that reduce the body’s immunological response. Some of these medicines have serious side effects, such as those used to prevent rejection of transplanted organs. Others are much safer, such as the vitamin derivative nicotinamide and the hormone insulin. Studies in Canada, the United States, and Europe are looking at whether diabetes may be prevented in high-risk groups by giving these medicines.
Preventing the progression of type 1 diabetes
For those who already have diabetes, there are 2 lines of research looking at ways to reverse the condition:
- Immune interventions at diagnosis. This would stop further damage to the pancreas and maintain the "honeymoon period."
- Transplanting the pancreas, or at least the islet cells. This would reverse the condition once it is fully established.
So far, interventions at diagnosis have been either totally unsuccessful or only slightly successful. There are currently no treatments approved for routine use.
Pancreatic transplants
The first pancreatic transplants were done in the 1960s. Transplants continue to be done in many centres around the word. The problem with this operation is that the transplanted pancreas may be rejected by the body. To prevent this, people who get a transplant must take high doses of anti-rejection medicines. These medicines can have serious side effects, including the development of cancer and type 2 diabetes.
Some people need a kidney transplant for serious diabetes-related kidney complications. They will need to use anti-rejection drugs anyway, so transplanting the pancreas at the same time makes sense. For those well controlled on insulin, with no sign of kidney complications, transplantation is a less obvious choice. Almost no transplants have been done in young people with diabetes.
Islet-cell transplants
Huge efforts have been made to take out the islets and transplant them without the other parts of the pancreas that don’t produce insulin. There have been recent advances in islet-transplantation technology. However, lots of testing is still needed before it becomes more common. People who receive transplanted islet cells need drugs that suppress their immune systems so that transplanted cells aren’t rejected. Even if the technical and rejection problems can be solved, it is expected that each person getting an islet transplant will need pancreases from 2 to 3 organ donors. This is a major stumbling block that prevents islet-cell transplants from becoming a realistic solution to type 1 diabetes.
Creating new islet cells
The next phase of research involves genetic engineering. With genetic engineering, either animal or non-islet cells are genetically changed to become functioning islet cells. Islet cell function is very complicated, but it is being discovered steadily. This is helping researchers target the genes that must function to make the cells produce and secrete insulin in response to changes in blood glucose levels.