Uses in Research
Stem cells are very important for life and their application in treatment of major diseases has already been discussed. Now shifting to their use in research in trying to find out how the complex developmental events take place, in testing of drugs, using them in gene therapy and other potential applications.
A new window on human developmental biology: The study of human developmental biology is particularly constrained by practical and ethical limitations. Human embryonic stem cells may allow scientists to investigate how early human cells become committed to the major lineages of the body: how theses lineages lay down the rudiments of the body's tissues and organs: and how cells within these rudiments differentiate to form the myriad functional cells types which underlie normal function in the adult. We know that turning genes on and off is central to the process of specialization of cells, but we do not know much about these "decision-making" genes or what turns them on or off. Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell specialization and cell division better understanding of normal cell processes will allow us to further delineate the fundamental errors that cause these often-deadly illnesses.
Models of human disease that are constrained by current animal and cell culture models: Investigation of a number of human diseases is severely constrained by a lack of in-vitro models. A number of pathogenic viruses including HIV and Hepatitis C virus grow only in human or chimpanzee cells. Embryonic stem cells might provide cell and tissue types that will greatly accelerate investigation into these and other viral diseases. Current animal models of neuro-degenerative diseases such as Alzheimer's Disease give only a very partial representation of the disease's process.
Drug development and safety testing: New medication could be initially be tested using human cell lines. Pluripotent stem cells would allow testing in more cell types. This would not replace testing in whole animals and testing in humans, but it would streamline the process of drug development. Only the drugs that are safe and appear to have a beneficial effect in cell line testing would graduate to further testing in laboratory animals and human subjects.