Stem Cell Research
Stem cells are cells found in all multicellular organisms. Stem cells can differentiate into any type of cell such as a red blood cell, nerve cell, etc. The two types of stem cells are embryonic stem cells and adult stem cells. Embryonic stem cells can specialise into any cell type, while adult stem cells usually have some restrictions as to what type of cell they can become.
Adult stem cells are produced in various tissues including the liver and the bone marrow. Embryonic stem cells are obtained from embryos and can be created in vitro (in the laboratory). Multiple embryos are generated through in vitro fertilisation methods, in which egg cells are harvested from the mother and fertilised by sperm cells from the father, outside of the body. The embryos that are not implanted into a patient are frozen or stored. Some of them are destroyed. The potential uses for stem cells include:
- Spinal cord injury: Repairing damaged nerve tissue after paralysis.
- Brain damage: Replacing or regenerating neurons in degenerative conditions like Parkinson’s disease or after a stroke.
- Cancer: Creating new cells to replace cancerous cells e.g. bone marrow transplants for people with leukaemia.
- Burn treatment: New skin cells that match the donor may be grafted onto burn victims.
The figure below shows how embryonic cells differentiate to form nerve cells.
Recall that in a previous tutorial, you learnt that individuals with cancer can be treated through chemotherapy and radiation. However, these therapies often destroy healthy cells along with cancerous cells. The use of adult stem cells which derive from the bone marrow and liver tissue is important in replacing the healthy cells damaged by chemotherapy.
The use of stem cells and embryonic stem cells in particular, is controversial, with many people opposed to it for moral, religious or philosophical reasons. The objection is largely based on what happens to the unused embryos.
Video: Stem Cells
Are you confused about stem cells? Watch this entertaining video by SciShow that explains what stem cells are and why they are so exciting.