Stem Cell Therapies in Regenerative Medicine and Diabetes Mellitus: Advances, Constraints and Future Prospects

Stem cell therapy is one of the most promising treatments for the near future. This kind of therapy can ameliorate or even reverse some diseases and have potential applications in regenerative and replacement medicines and diabetes mellitus. The different types of stem cells such as embryonic stem cells, induced pluripotent stem cells and adult stem cells have been proved to be operational in treating diabetes mellitus with clear limitations. The prevalence of diabetes mellitus type 1 and type 2 continues to rise and its complications are serious and may lead to death. The current treatment methods, other than stem cell therapy, do not treat the main causes of the disease and have many limitations. Although insulin injection is the standard therapy for type 1 diabetes mellitus, its exogenous injection cannot mimic insulin secretion from normal β-cells when blood glucose changes all the time. Thus, how to generate new β-cells is an important approach for the treatment of type 1 diabetes mellitus. Isolated islets are fragile and susceptible to pro-apoptotic factors and poorly proliferative. In contrast, mesenchymal stem cells (MSCs) are highly proliferative, anti-apoptotic and pluripotent to differentiate toward various cell types. The electrofusion between islets´ cells and MSCs produced fusion islets´ cells that are more resistant to apoptosis and are able to maintain insulin secretion for long periods. The stem cell therapy is also used for treatment of type 2 diabetes mellitus as well because the disease later progresses to β-cell dysfunction. Stem cell therapies were clinically applied for improvement of insulin sensitivity and metabolic control in long standing type 2 diabetes mellitus. In addition to the applications of stem cells in the cell therapy of diabetes mellitus, recent trends of studies tend to use the direct reprogrammed adult somatic cells especially endoderm-derived adult cells transdifferentiated into insulin secretory pancreatic β-cells. However, the use of stem cells especially human embryonic stem cells in research and therapy is subjected to limitations and constraints in many countries due to ethical and religious concerns. In this article, the types of stem cells and their resources and to what extent stem cell research can lead to progresses in regenerative medicine and diabetes mellitus therapies are reviewed. It also sheds light on ethical concerns and future hopes of stem cell use in research and therapy.