Stem Cells and Their Application
Stem cells are known for their ability to differentiate into a wide range of cell types (Takahashi & Yamanaka, 2013). The naturally occurring stem cells include embryonic and adult stem cells (Phuc et al., 2011). The adult ones are found in some organs and in cord blood, and can be further classified into hematopoietic, mesenchymal, and endothelial progenitor stem cells (Phuc et al., 2011). While embryonic stem cells can give rise to all tissue types, the adult ones are limited to one or several tissues. However, unlike the embryonic cells, adult stem cells do not lead to development of tumors, and their application does not rise ethical issues (Phuc et al., 2011). To resolve this issue, induced pluripotent stem cells, characterized by high level of totipotency but low risks for adverse effects, have been developed artificially (Takahashi & Yamanaka, 2013). Today, stem cells can be used for regeneration of damaged tissues, disease modelling, and drug screening (Takahashi & Yamanaka, 2013). Both adult and pluripotent stem cells are commonly applied for the management of diseases associated with degenerated tissues.
Diabetes mellitus is a group of metabolic conditions, which are characterized by reduced level of insulin production, low sensitivity of tissues to this hormone, or both abnormalities (American Diabetes Association, 2011). As stem cell therapy is primarily used for the management of damaged tissues (Takahashi & Yamanaka, 2013), it can be efficiently applied mainly to type I diabetes, which is caused by autoimmune destruction of pancreas (Lu, Xia, & Zhou, 2016). The most challenging approach in the treatment of this condition in humans is application of induced pluripotent stem cells (Lu et al., 2016). This technology includes the induced dedifferentiation of mature cells with further application of growth factors, which stimulate their development into the required type (Lu et al., 2016). The maturation of induced pluripotent stem cells into β cells of the pancreas takes place under the application of retinoic acid, fibroblast growth factor, bone morphogenic protein, transforming growth factor β, and others (Lu et al., 2016). The obtained mass of differentiated cells is encapsulated for prevention of attacks from autoreactive immune system of patients with type I diabetes, and is delivered into the patient’s organism (Lu et al., 2016). Clinical trials show positive outcomes of this approach.
Alzheimer’s disease is a neurodegenerative condition, which is the leading cause of dementia worldwide (Choi, Lee, Kim, & Lee, 2014). The pathophysiology of this condition is associated with destruction of nerve cells within the central nervous system due to accumulation of protein aggregates (Choi et al., 2014). Damage of brain tissue is the reason for the significant cognitive impairment observed among the patients. Therefore, this condition could be treated with the application of stem cells. However, this approach has been applied on animal models of Alzheimer’s disease only (Choi et al., 2014). At the same time, the attempts were successful.
Stem cell therapy of Alzheimer’s disease has two main goals: activation of endogenous stem cells within the patient’s brain tissue, …
