This extraordinary research is still in its infancy and practical application will only be possible with additional study. Scientists need to understand what leads to cell specialization in order to direct cells to form particular tissue types. For example, islet cells control insulin production in the pancreas, which is disrupted in people with diabetes. If an individual with diabetes is to be cured, the stem cells used for treatment must develop into new insulin-producing islet cells, not heart tissue or other cells. Research is required to determine how to control the differentiation of stem cells so they will be therapeutically effective.
Research is also necessary to study the potential of immune rejection of the cells.
Stem cell research will shed light on abnormal cell growth and could help treat and perhaps prevent birth defects and cancer. Stem cells also could be used for testing pharmaceutical products on specific cell types, which would speed the development of drug therapies and reduce the number of animal studies and human clinical trials. One of the most promising ways of curing diabetes is to biologically restore the function of islet cells. At the present time, this can occur either through islet cell transplantation or through engineering of cells to restore the insulin secreting function. In both instances, the availability of stem cells would significantly expedite research progress.