Question

•What is the primary risk of using human ES cells in cell replacement therapy to treat diseases like type I diabetes and macular degeneration?  Why is this a risk?

Answer 1

The primary risk of using human ES cells in cell replacement therapy to treat diseases such as Type I diabetes and eye diesease macular degeneration is the unnoticed presence of undifferentiated ES cells among the differentiated cell population. These undifferentiated cells are capable of forming a type of benign tumor called teratoma, which may contain a bizarre mass of various undifferentiated tissues, including hair and teeth. The formation of teratoma within a central nervous system could have severe consequences. In addition, culture of ES cells involves the use of nonhuman biological materials, which also pose a potential risk of causing diseases.

Although adult stem cells lack the unlimited differentiation capacity that is characteristic of ES cells, they do have an advantage over ES cells in that they can be isolated from the individual who is being treated and will thus not face immunological rejection when used in subsequent cell replacement.Adult stem cells do not seem to have anunlimited potential to proliferate as is characteristic of ES cells.