Beta cell transplantation
According to the results of a new clinical study, transplantation of pancreatic islets containing insulin-producing beta cells prevents the development of episodes of severe hypoglycemia in patients with type 1 diabetes mellitus – a severe decrease in blood glucose levels, in some cases leading to seizures, loss of consciousness and death, even with timely medical intervention.
In type 1 diabetes, the immune system attacks and destroys the insulin-producing cells of the pancreatic islets. Patients with this disease throughout their lives need regular injections of the hormone insulin, which ensures the movement of glucose from the bloodstream to the cells, where it acts as the main source of energy. However, even against the background of insulin therapy, fluctuations in the concentration of glucose in the blood often occur in such patients.
Hypoglycemia – a decrease in the level of sugar (glucose) in the blood – is usually accompanied by symptoms such as tremor, profuse sweating and palpitations. This forces a person to eat or drink in order to increase glucose levels. People with impaired recognition of hypoglycemia who do not experience these early alarming manifestations are at risk for the development of severe hypoglycemic conditions in which a person cannot take food on their own. Interventions such as behavioral therapy or constant monitoring of blood glucose levels in many cases help to avoid such situations, but a significant proportion of people with this condition are still at high risk.
The phase 3 clinical trial involved 48 patients with stable glycemic recognition disorder who fall into severe glycemic conditions despite high-quality medical care. Researchers at eight medical centers in North America used a standardized protocol for obtaining purified insulin-producing islets from the pancreas of cadaveric donors. Each of the study participants underwent at least one injection of islets into the portal vein, a large blood vessel connecting the intestine to the liver. To prevent rejection of transplanted cells by the immune system, these patients should take immunosuppressive drugs throughout their life after transplantation.
A year after transplantation, 88% of the participants no longer had severe hypoglycemic conditions, while the level of regulation of blood glucose levels rose to almost normal values, which was accompanied by the restoration of recognition of hypoglycemia. 2 years after transplantation, 71% of the participants continued to meet the criteria for transplant success.
Even a small number of functioning insulin-producing cells is sufficient to restore the ability to recognize hypoglycemia, however, their recipients may need to maintain insulin replacement therapy for complete control over blood glucose levels. Patients in need of insulin therapy were given a second injection 75 days after the first injection of the islets. As a result, 25 patients underwent 2 and 1 patient underwent 3 transplants of insulin–producing islets. A year later, 52% of the participants did not need insulin injections.
Researchers continue to monitor the condition of patients in order to determine whether the benefits of restoring control over insulin levels in the blood to almost normal values and protection from the development of severe hypoglycemic conditions outweigh the risks associated with constant use of immunosuppressive drugs.
Article by Bernhard J. Hering et al. Phase 3 Trial of Transplantation of Human Islets in Type 1 Diabetes Complicated by Severe Hypoglycemia is published in the journal Diabetes Care.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru Based on NIH/National Institute of Allergy and Infectious Diseases: Islet Transplantation Restores Blood Sugar Awareness and Control in Type 1 Diabetes.
21.04.2016