- Are there stem cell therapies available for type 1 diabetes?
- How close are we? What do we know about type 1 diabetes?
- What research is underway?
- Further reading on type 1 diabetes
Are there stem cell therapies available for type 1 diabetes?
To our knowledge, no stem cell therapy has received Health Canada or U.S. Food and Drug Administration approval for treatment of type 1 diabetes at this time. Patients who are researching their options may come across companies with Web sites or materials that say otherwise and offer fee-based stem cell treatments for curing this disease. Many of these claims are not supported by sound scientific evidence and patients considering these therapies are encouraged to review some of the links below before making crucial decisions about their treatment plan.
For the latest developments read our blog entries here.
More about stem cell clinical trials for diabetes click here. (For printed version: http://goo.gl/ibYMN)
How close are we? What do we know about type 1 diabetes?
- The insulin-producing beta cells of the pancreas are attacked and destroyed by the body’s immune system cells.
- A person’s environment, genetics and the infections they are exposed to over their lifetime all play a role in triggering the attack on beta cells.
- When the beta cells are destroyed, the production of insulin drops and our cells can no longer take in the sugar glucose.
- When glucose is left circulating in the blood at very high levels the blood vessels, eyes, kidneys, nerves and heart can be damaged.
- If type 1 diabetes is not diagnosed and treated in time with injections of insulin, a patient could fall into a life-threatening coma.
- Just a few teaspoonfuls of pancreatic islet cells can temporarily reverse type 1 diabetes.
- There is a shortage of donor pancreatic islet cells for treating patients with type 1 diabetes.
How can stem cells play a part?
Type 1 diabetes is an ideal candidate for a stem cell therapy because the disease can be traced to the loss of a single cell type – the beta cell. Stem cells have an unparalleled regenerative capacity and the flexibility to grow into hundreds of different types of cells, including beta cells. Researchers are looking at two main ways of using stem cells for treating type 1 diabetes: as beta-cell producing factories or as cells that support beta cell repair in the patient. Either way, the end goal of returning insulin to normal levels is the same. In theory a stem cell therapy could make new inroads to treatment because it could free diabetic patients from the daily dependence on insulin injections and also address the current shortage of donor tissue for pancreatic islet cell transplants. No existing therapies are able to accomplish both.
Are there lots of groups working on developing a stem cell therapy?
There are countless research teams around the globe working to develop stem cell therapies for type 1 diabetes. Their common goals are to identify which stem cells are best suited for the job, which signals will be able to coax them into becoming insulin-producing beta cells, and the large scale lab methods required for ramping up the production of stem cells and beta cells.
One of the most important research contributions to date has come from a group of Canadian researchers. In 2000 they developed the Edmonton protocol, a transplant method that involves administering a few teaspoonfuls of donated pancreatic islet cells to patients with type 1 diabetes. The success of this cell therapy for temporarily reversing type 1 diabetes in patients has been tremendously important for reassuring scientists that pursuing a stem cell therapy is a realistic goal. The Edmonton protocol is now considered a gold standard for treating type 1 diabetes and many research teams are working to overcome some of the hurdles that are limiting its more widespread use.
Stem cell research for type 1 diabetes is unfolding along a number of different routes and some of the stops along the way have yielded results that are being translated into early Phase 1 and 2 clinical trials. The majority of these are testing the safety of adult stem cells and the outlook is promising. Researchers are also investigating combination approaches that infuse stem cells along with pancreatic islet cells to protect and improve the engraftment of the islets and reduce the need for insulin injections.
What research is underway?
Before basic stem cell research can be translated into the clinic for patients, it must first be rigorously tested and validated. For type 1 diabetes, this involves transplanting stem cells into animal models of diabetes to test if insulin levels can be restored. The main types of adult stem cells being considered for type 1 diabetes are hematopoietic stem cells, mesenchymal stem cells, pancreatic stem cells and liver stem cells. The pancreatic and liver stem cells are still some way off the clinical trial setting because they are quite difficult to isolate, expand and grow into beta cells. In contrast, there are many clinical trials evaluating the safety and feasibility of using hematopoietic stem cells or mesenchymal stem cells for treating type 1 diabetes. Hematopoietic stem cells are found in the bone marrow and are responsible for making all the red and white blood cells in the body. Mesenchymal stem cells are found in bone marrow as well as in many other tissues and can grow into a variety of different cell types.
The road to finding a stem cell therapy for type 1 diabetes is paved with many challenges that will take time to overcome. But the wealth of information generated from labs around the globe is converging to help with the transition from basic research to the clinic. The results are very promising and in time may point to a viable stem cell therapy for type 1 diabetes that accomplishes more than any of the current therapies by freeing patients of their life-long dependency on insulin injections and supplying limitless quantities of beta cells.
Current research using adult stem cells
Hematopoietic stem cells are able to support beta cell regeneration in damaged pancreas tissue, and as bone marrow transplantation procedures have been taking place since the 1960s, hematopoietic stem cells are a leading candidate for a possible therapy. Mesenchymal stem cells, a newer stem cell on the block, live in the bone marrow and other tissues and also have the regenerative potential to repair beta cells. Both types of stem cells, when harvested from the bone marrow, have an intrinsic ability to modulate the immune system. This is important because newly formed beta cells, regardless of how they are made, will need to be protected if they are to avoid the same autoimmune response that attacked the patient’s beta cells in the first place. Currently there are many clinical trials underway to test if hematopoietic stem cells and mesenchymal stem cells can offset the amount of insulin needed by diabetics to manage their blood sugar levels.
Current research using embryonic stem cells
In nature, the master stem cell is the embryonic stem cell because it can make an entire human being. Scientists have devised methods for turning embryonic stem cells from mice and humans into insulin-producing beta cells that can keep blood sugar levels in diabetic mice in check. Translating these results into clinical trials is not as easy as it might seem because researchers must first devise rigorous strategies to separate the newly formed beta cells from their embryonic stem cell parents. This is a crucial step because embryonic stem cells are so potent that they can sometimes form a type of tumour called a teratoma. Ethical concerns about harvesting embryonic stem cells are another hurdle that may hamper their future as therapeutic agents. At present, to our knowledge there are no clinical trials testing embryonic stem cells in humans for treating type 1 diabetes.
Current research using induced pluripotent stem cells
Researchers have found a way to turn back the clock on adult cells and reprogram them to act like embryonic stem cells. These man-made stem cells are called induced pluripotent stem cells or iPS cells (‘pluripotent’ from the Latin words ‘very many’ and ‘having power’) and they can be made from skin or other tissue cells. These iPS cells offer the advantages of embryonic stem cells without the controversy about the source. In 2010, researchers showed they could turn iPS cells into insulin-secreting beta-like cells that normalize blood sugar levels in diabetic mouse models. Researchers are devising safer ways of making iPS cells and these methods are getting them one step closer to testing in a clinical setting.
Another intriguing avenue of exploration was revealed in 2010 when researchers showed that sperm stem cells could be reprogrammed to become embryonic-like cells that could make beta-like cells. This method of making spermatogonial cells is very safe and the beta-like cells produced can lower high blood sugar in mouse models of diabetes. Spermatogonial stem cells, although male-centric, could potentially be a vast source of pluripotent cells.
Further reading on type 1 diabetes
Readers may wish to peruse the recommended sites and articles below for more information about type 1 diabetes and the possible applications of stem cells to treat this disease.
Canadian Diabetes Association (www.diabetes.ca)
Juvenile Diabetes Research Foundation Canada (www.jdrf.ca)
American Diabetes Association (www.diabetes.org)
National Institute of Diabetes and Digestive and Kidney Diseases (www2.niddk.nih.gov)
Public Health Agency of Canada (http://goo.gl/r5oAg)
International Diabetes Federation (www.idf.org)
World Health Organization Diabetes Program (www.who.int/diabetes)