Type 1 diabetes affects more than 1 million people in the United States. In these patients, the immune system attacks and kills the beta cells in the pancreas which produce the insulin necessary to regulate blood sugar. Without these cells, patients must inject doses of insulin to control their blood sugar and carefully monitor what they eat. Even with insulin, these patients are at risk of fainting due to low blood sugar and a host of chronic diseases, including cardiovascular disease, kidney failure, and blindness. Stem cells have been studied as a potential source of replacement cells for decades and the results of this research are finally nearing fruition.
Viacyte Inc., a regenerative medicine company based in San Diego is conducting clinical trials using embryonic stem cells to create new beta cells that will sense blood sugar levels and release insulin as needed. This would greatly simplify treatment, by eliminating the need for blood sugar monitoring and allowing for a more natural release of insulin. Their device consists of differentiated human embryonic stem cells (hESCs) enclosed in a thin permeable membrane. This membrane allows diffusion of oxygen, nutrients, insulin, and waste products while keeping the patient’s immune system from attacking the implanted cells. This will hopefully allow the implant to function for years without any outside interventions.
Recently two patients have been implanted with the latest design of this device and researchers are hopeful that they will stop needing outside insulin injections. The devices are implanted just below the skin and are about the size of a credit card, making this a less invasive treatment. Once implanted, blood vessels can grow around and into the device to support the cells. It also makes it possible to remove the device if any problems occur. In the future, this research might give hope to patients with type 2 diabetes. This type of diabetes is caused by a lack of response to insulin in addition to low production of insulin. Stem cells in combination with drug therapy has been studied in mouse models of type 2 diabetes with initial promising results.