Picture this: it’s the afternoon, sometime in February, and I’m sitting down again for my online Biology lesson on Google Classroom. Our teacher asks us to watch a video about a special type of cell and this catches my attention immediately. 

Now imagine this: a deaf man, his vision zapped to the point of reliance on permanent glasses, with missing teeth and diabetes is asked to visit the hospital for surgery: shortly after his operation, he is completely healed of all his disabilities. While this may sound too good to be true, there is a recurring theme between the two stories.

The link? Stem cells.

This mysterious cell type may soon be the birth of some of the most influential and life-changing medicines. But we must first understand how they function and what challenges they may bring about.

Stem cells are special human cells that are able to develop into many different cell types. Stem cells are undifferentiated (meaning they are not suited to a specific role), but they can divide by mitosis to differentiate into specialised cell types - they are particularly useful for growth and repair in humans which makes them vital for our survival.

Stem Cells in Humans:

In humans there are two stem cell types.

Embryonic stem cells are only found in the zygote and are specialised after development. However they are pluripotent - meaning they can differentiate into any type of cell in the organism, for example neurones (for the Central Nervous System) and muscle cells (for muscle contraction).

Adult stem cells, on the other hand, are found in specific tissues such as bone marrow and persist throughout the organism’s life, but are multipotent - meaning they can only differentiate into a limited number of cell types.

Stem Cells in Medicine:

One important use of stem cells is in treating blood diseases. Bone marrow from a healthy human containing adult stem cells is transplanted to the diseased human; these stem cells then divide and differentiate into healthy new blood cells to replace the diseased or damaged cells to help cure the diseased human of the blood disease.

Furthermore, scientists are researching how to make induced pluripotent stem cells (iPSCs). This would involve taking stem cells from an adult and reprogramming them to become pluripotent. iPSCs will not be rejected from a patient because they have the same sequence of DNA as the patient’s normal body cells and so will not be recognised as foreign cells by the immune system, thus avoiding an unnecessary immune response to fight the cells. 

Creating iPSCs will pave the way for unprecedented developments in modern medicine, including the ability for these special stem cells to repair damage to the cornea in the eye and to treat traumatic brain injury.

The issues with Stem Cell research and usage

However, there are risks to treating diseases with stem cells. One reason why it may be difficult to treat diseases in this way is that if stem cells continue to divide inside the body after they replace damaged cells they can cause cancer (through the build-up of excess lumps of specialised cells, known as a tumour), which could result in death to the human.

Additionally, if stem cells are transplanted from one individual to another they may be attacked and linked by the recipient’s immune system in a process called rejection - in this instance, the stem cells would not be able to divide and differentiate and so are unable to produce the required cells to treat the individual.

Indeed, many people argue that there are unethical implications of using stem cells to treat disease: in the case of embryonic stem cells, they must be removed from embryos, which destroys the embryo itself as it would not be able to grow or repair with new cells to replace damaged ones - some people consider this to be immoral as they see it as the ending of a life, but this heavily depends on a person’s interpretation as to when life actually begins.

 

Stem cells have the potential to become the most revolutionary advance in modern science, however care must be taken in how they are used and how the public may react to their use in everyday life with regards to their moral, ethical and cultural issues.

 

Glossary:

Stem cells - unspecialised human cells that are able to develop into many different cell types through dividing and differentiating into specialised cells; mainly used in humans for growth and repair.

 

Embryonic stem cells - stem cells found in the zygote, specialised after development, and do not persist throughout the organism’s life. Can develop into any type of cell in the organism’s body.

 

Adult stem cells - stem cells found in specific tissues (e.g. bone marrow), and persist throughout the organism’s life. Can only develop into a limited number of cell types in the organism’s body.

 

Pluripotency - an attribute of embryonic stem cells which refers to the ability to divide and differentiate into any cell type.

 

Multipotency - an attribute of adult stem cells which refers to the ability to divide and differentiate into a limited number of cell types.

 

Mitosis - a form of cell division common in stem cells, whereby the cell replicates its DNA and divides to form two genetically identical daughter cells.