The recently hyped advance from the stem cell world of the creation of mature insulin-secreting ?-cells of the pancreas signal a game-changer for patients with type 1 diabetes the world over. In type 1 diabetes the ?-cells from the Islet’s of Langerhans within the pancreas, that produce insulin in a healthy individual, do not work. This results in daily injections of insulin for diabetic patients to enable them to properly digest food and maintain blood sugar levels.
The new creation of insulin-secreting mature pancreatic ?-cells from human stem cells offers a potentially unlimited supply of these cells, and opens up the possibility of transplantation for diabetic patients, negating the need for multiple daily injections and improving the quality of life for many. Previous work has resulted in immature ?-cells that have been transplanted into mice, though they take many months to mature into insulin-secreting cells and it is unclear whether they would do this in humans.
A team of researchers led by Douglas Melton of Harvard University announced earlier this month that they have identified a way to generate ?-cells from human embryonic stem cells in sufficient numbers so as to make implantation into patients a real possibility. When they implanted the cells into diabetic mice the symptoms were relieved within two weeks. The cells even form clusters similar to the Islets of Langerhans in the pancreas. They are currently being tested in non-human primates to assess their suitability for transplantation and functional survival within patients.
The final barrier to human implantation and curing patients with diabetes is to shield the cells from immune attack. Currently immunosuppressant drugs are given to patients accepting ?-cells from cadavers, to prevent their immune system rejecting the foreign cells. Although the stem cell derived ?-cells can be created from the patient’s own skin cells immunosuppressants are still required as diabetes is an autoimmune disease, leaving the new cells still vulnerable to attack.
Current options to avoid the immune response include encapsulating the cells within a biocompatible coating. One such example of which is made by ViaCyte, San Diego, and is set to be inserted into the first patient on the 21st of October. However, some researchers are worried that the cells are packed too densely within ViaCyte’s coating, which may starve them of oxygen and nutrients. This form of cell delivery does not escape the body’s immune response of enclosing foreign bodies in scar issue, again rendering the transplanted cells starved of nutrients, and scientists are continuing to hunt for a chemical that will allow transplantation of the cells without activating the patient’s immune system.
For diabetics struggling with unstable blood sugar levels and associated complications of cardiovascular disease, stroke, kidney damage and retinopathies this break-through offers real hope for a cure that may be within touching distance.