Last March the American Diabetes Association (ADA) applauded President Obama's executive order that will advance stem cell research by lifting existing restrictions on the use of embryonic stem cells, while maintaining strict ethical guidelines.

"The ethical use of stem cell research holds the promise of accelerating medical advancements in many fields. This brings hope to the nearly 24 million American adults and children with diabetes who face its many complications including heart disease, amputation, and blindness," said R. Paul Robertson, M.D., president of medicine and science at the ADA. "Diabetes is also deadly--it is a leading cause of death in the United States."

Stem cells are unspecialized cells that can develop into many different types of cells in the body. They also help to repair and regenerate cells. Under certain conditions, they can be made to turn into organ- or tissue-specific cells with special functions.

Stem cell research has been around for over 50 years. Initially, researchers used adult stem cells, however, in most cases, these cells are capable of developing only into cells of the organ system they come from. While the use of embryonic stem cells remains ethically controversial, they potentially provide far more versatility in treating chronic diseases, including diabetes.

In 2006, researchers at the biotechnology company Novocell developed a way to convert human embryonic stem cells into insulin-producing pancreatic cells. In 2007, Geron Corp reported using growth factors to coax human embryonic stem cells to develop into islet-like clusters that produce insulin in response to glucose.

More recently, stem cell research at the University of California San Diego and Burnham Institute for Medical Research revealed that the Wnt signaling pathway involved in normal pancreatic development is also associated with type 2 diabetes.

"The Wnt signaling pathway is a series of protein interactions that control several genes and play a role in normal development, as well as cancer, in many tissues. In this study, the scientists compared how different proteins behaved in the Wnt pathway in the pancreas from adults with type 2 diabetes and those from healthy individuals."

People without type 2 diabetes had low levels of beta-catenin, a protein that enters cell nuclei and activates certain genes. The beta cells from people with type 2 diabetes had increased levels of the protein. Activation of the Wnt pathway also affects the expression of c-myc, which plays a role in destroying insulin-producing beta cells.

Stem cell research has also made headway in the treatment of type 1 diabetes. In 2007 a joint US and Brazilian research team implanted into type 1 diabetes patients their own stem cells. Most became insulin free within 19 months. The team conducted a second study, which was published in the Journal of the American Medical Association earlier this year, to investigate if the effect was due to preservation of beta-cell mass (in people with type 1 diabetes the immune system destroys beta cells).

The team monitored the C-peptide levels after stem cell transplantation in the 15 original and eight additional patients. Over a seven to 58-month follow-up period, 20 patients became insulin independent. Twelve patients remained insulin free for between 14 and 52 months, while eight relapsed and resumed low-dose insulin. In the group that remained insulin-free, HbA1c levels remained low (under seven per cent) and the C-peptide levels went up significantly (the more C-peptide someone with type 1 diabetes has, the less severe their condition).

Although no one is using the word "cure" yet, the researchers add that "at the present time, this remains the only treatment capable of reversing type 1 diabetes mellitus in humans." More research is needed--including larger studies using control groups--but for people living with diabetes, the findings of this stem cell research are very promising.

Source: Burnham Institute for Medical Research press release

Study Reference

Journal: The Journal of the American Medical Association, Vol. 301 No. 15, 1573-1579

Date: April 15, 2009

Study Name: C-Peptide Levels and Insulin Independence Following Autologous Nonmyeloablative Hematopoietic Stem Cell Transplantation in Newly Diagnosed Type 1 Diabetes Mellitus


Authors: Richard K. Burt, MD; Júlio C. Voltarelli, MD, PhD, et. al.