● Where do embryonic stem cells come from and why is their use controversial?
● Are somatic stem cells a good alternative? Why or why not?
● wht are induced pleuripotent stem cells (IPSCs)? Describe two advantages of IPSCs.
Stem Cells (SC) have the ability to develop into many different cell types during early life. They can replenish and repair different types of tissue. When a stem cell divides it can become a new stem cell, or differentiate into another, more specific type of cell such as a blood cell, brain cell or liver cell.
Stem cells are medically useful because they can be stimulated to become a specific cell type needed to repair or replace tissue or an organ. They are uncommitted and therefore represent a cellular “wild-card” that can be induced to become any needed cell type.
Embryonic Stem Cells (ESS): Embryos, by nature of their primitive stage of development are a rich source of stem cells. In SC research, embryos are harvested from in vitro fertilization. After the SC are harvested, the embryos are donated for research (with donor consent).
Controversy: The use of ESS is controversial because many feel the embryos from which they came are living creatures and should not be sacrificed for medical science. Furthermore, some feel that creation of “life “ and growing of these cells in the laboratory in this manner is immoral.
Somatic (Adult) Stem Cells (SSC): These have been found in many adult organs that have the ability of rapid cellular turnover, and self-repair. They have been found in many organs, even the brain. It is hoped that science can learn how to harvest these cells, then induce them to become organ cell types needed to replace or repair diseased or deficient organs. An example this treatment would be the use of spinal cord stem cells to treat paralysis.
Induced Pleuripotent Stem Cells (iPSC): These are adult cells that have been genetically reprogrammed to become like embryonic SC. It is not yet known if they will be as useful as ECC in treatment of disease.
Note: Use of somaatic stem cells or iPSC bypasses the moral/ethical issues associated with the use of embryonic stem cells.
The reference is an exhaustive treatise on stem cells, produced by the National Institutes of Health.