Stem Cell Blog- Yoonsik Park (Oct,5th, 2015)

Yoonsik Park
1. What Are Stem Cells?

         According to the IB-guides website, they are cells that have not been fully differentiated, however, they have the ability to divide and differentiate into different types of cells. For example, a stem cell can differentiate into a brain cell, or a blood cell. As you can see in (picture 1), a stem cell can duplicate itself or differentiate into many cell types. They are necessary in embryonic development because all of the cells in an adult organism come from stem cells. 

 (http://ibguides.com/biology-2016/notes/stem-cells)

   

(Picture 1)    http://nas-sites.org/stemcells/files/2013/01/What-Is-Download.jpg

Development of embryonic stem cells:  A zygote is formed when an egg cell from the female and a sperm cell from the male fuse. The zygote then divides into a two celled embryo. That embryo will keep dividing into a 4 celled, 8 celled and so on. In the early stages of development, the embryo cells are stem cells because they have the potential to become any type of cell. As the embryo cells divide, they eventually start to be committed to a specific path. (For example, as you can see in picture 2, some cells will become committed to liver cells, nerve cells, cardiac cells, blood cells, or something else)

At this point, although they still have the ability to differentiate, they can only differentiate into the type of cells that they are committed to. (For example, if an embryo cell is committed to a kidney cell, they can only differentiate into that, not liver or blood cells.) So they are no longer stem cells, but they are uni-potent.

(Picture 2) http://www.extremetech.com/wp-content/uploads/2014/07/stem-cells.jpg

Adult Stem Cells: There are still some stem cells in an adult organism. (Can be found in the skin, bone marrow, and liver) They are able to differentiate into different cells but not as much as the embryonic stem cells. So they are not as effective. However, they still benefit adult organisms greatly by regenerating and repairing damaged tissues.

 (http://ibguides.com/biology-2016/notes/stem-cells)

2. Therapeutic Potential of Stem Cells

Since stem cells can differentiate many times and into different cells, they are the best for therapeutic use in degenerative disease or tissue repair.
Therapeutic : "The branch of medicine that is concerned specially with the treatment of disease."             (http://www.medicinenet.com/script/main/art.asp?articlekey=18811) 

One example of therapeutic potential of stem cells-
Umbilical Cord Blood Stem Cells: 

(Picture 3) https://upload.wikimedia.org/wikipedia/commons/f/f3/Umbilicalcord.jpg

 As you can see  in (picture 3), the  umbilical cord is  no longer needed  to the survival of  the baby or the  mother when the  baby is born. So  it is usually  thrown away  after the baby is  born and is cut  off from the baby  and the mother's  body. However, it  has been discovered recently that the blood, rich of stem  cells, from the umbilical cord can also be used to treat  problems that are treated by bone marrow stem cells and  peripheral blood stem cells.
 Umbilical cord blood stem cell transplants have a  lower possibility of rejection than other blood stem cells. This  is believed to be because they are not as developed yet,  which means that there are not as many immune cells; it is  less possible that the cells will react badly in the transplant  recipient's body. Because umbilical cord blood stem cells are  capable of adapting easily, and are available very much, it  makes them a potential resource for therapeutics.

      (http://learn.genetics.utah.edu/content/stemcells/sctoday/)

 3. Ethical Considerations of Stem Cell Therapy

Using stem cells to treat diseases and tissue repairs is very helpful in many ways. However, there has been some controversy over the studying, using, and destroying of human embryos for research and therapy using embryonic stem cells. 

(Against embryonic stem cell therapy) Since the embryo is the result of the sperm and egg fusing and developing, many people consider destroying human embryos after the research or extraction of stem cells as unethical. As you can see in picture 4, since extracting the stem cells destroys them from developing further, they consider it murder; the embryos have the potential become new babies.

(Picture 4) - http://federation-pro-europa-christiana.org/wordpress/wp-content/uploads/2011/12/Stem-cell-research.jpg

(For embryonic stem cell therapy) However, there are those who argue for embryonic stem cell research. One of their main arguments is that the embryo is only a few cells clumped together, so it cannot be considered as life yet. "It cannot survive outside the womb on its own so it cannot be considered life." Secondly, they claim that the research being done will benefit humans widely so it is justifiable. Also, according to the PubMed Central website, embryos that are used in research are donated by the woman or the couple.
(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2726839/)