Embryonic Stem Cells vs. Induced Pluripotent Stem Cells
ESCs are formed from a human embryo using the undifferentiated internal mass of cells. In contrast, IPSCs are produced from the reprogramming of different types of somatic cell types from diverse animal species.
Both types of stem cells are pluripotent, meaning that they can differentiate into products of the three key germ layers, namely endoderm, mesoderm and ectoderm. Other similarities include the formation of teratomas, morphology, propagation and production of embryoid bodies. The two types of stem cells can also express stem cell surface markers.
IPSCs and ESCs have similar therapeutic uses. They have been used in the treatment of cellular diseases such as type 1 diabetes, Parkinson’s disease and Alzheimer’s disease. This treatment has been achieved through the replacement of aberrant cells. Other therapeutic uses include treating blood diseases, disorders of the immune system associated with genes, blindness, malignancies and spinal cord lesions.
Potential Clinical Benefits
IPSCs provide an avenue to explore the fundamental principles of developmental biology, drug discovery, understanding disease course and conducting toxicological evaluations. The ability of IPSCs and ESCs to propagate in vitro without losing the capacity to differentiate into different cells of the body means that a limitless number of patient-specific somatic cells can be availed for various purposes including transplantation treatments. The benefit of using patient-specific cells during transplant procedures is that they circumvent the probability of immunological rejection. The somatic origin of human IPSCs eradicates ethical issues that arise from human ESCs.
Potential Clinical Disadvantages
The safety of IPSCs has not been ascertained in some cases, which necessitates additional studies. During the production of IPSCs, retroviruses used are linked to cancer due to their ability to insert DNA arbitrarily in the genome, which could prompt oncogenes. The reprogramming of IPSCs uses the c-Myc gene, an oncogene that leads to cancer when overexpressed. Low reprogramming rates have been reported when producing human IPSCs from fibroblasts thus limiting their availability for therapeutic uses. Human ESCs have raised ethical issues because of their embryonic origin. Their production entails the destruction of human embryos, which goes against the ethical belief that life begins at conception. Another shortcoming of ESCs and IPSCs is inadequate knowledge concerning them. They can divide uncontrollably, leading to the formation of tumors that can pose serious health risks.