Stem cells, and nope I don’t mean the acronym for science, technology, engineering and math which this blog is focused on. (hint hint – self-promotion, there are also many other interesting posts which Susan and I have written). I mean the unspecialised cells which have the ability to cure currently untreatable diseases. In plants, these cells are known as meristems, usually found in the root and shoot tips. In our bodies there are two types of stem cells. Beginning in the chronological order in which the types appear in our body is the embryonic stems, seen below.
So this is the first one with the funny name, oocyte. The oocyte is like an egg which is not ready to be an egg, or eventually you. It is a single cell and during fertilisation, when the two nuclei of the sperm and the not-quite-an-egg-egg fuse together and become diploid. Now the cells has two copies of the DNA one from the mother and one from the father. From this stage it is a totipotent cell with the ability to become ANY cell in the body and even become part of the placenta. (Wow!!!, is what you should be thinking) It’s not everyday that a cell can do this, well except when the oocyte undergoes mitosis three times to become the 8 cell embryo. It is at this point where the controversy begins. The embryo grows and develops into a ball of cells called a blastocyst. At this stage, it is ready to be taken to be used for medical research. Even now, it is pluripotent which is able to delvelop into all body cells but not including the placenta. During the division period, it has lost the ability to become the placenta. This is due to the fact that the genes which code for certain proteins to make up the placenta are switched off as they are no longer needed. Many people are against the culture of embryonic stem cells as they argue that this is destroying an innocent life, maybe even branded as murder. That could be me going to far, but is is not hard to see why they think this. To be killing a life then the blastocyst would be defined as a ‘person’. There is also a whole heated philosophical argument around what makes a person, a person. Some say, from the moment of conception, others say only after birth. But these are only rough timescales for a definition to be based on. What about the second before or after conception and birth, a nanosecond? Or an appropriate imdicator would be when the cells obtain a concience, the sort of ‘I think therefore I am’ idea? This is also not with out its problems, out of all the different ways of measuring concience, which would be the one? These ethical issues are the reason for the supply of embryonic stems cells to be extremely monitored.
Away from the depressing nature of the previous type, lets venture into the world of adult stem cells. Suprise, it is sourced from ‘people’ which are accepted as people, like you and me. They are taken from places such as the brain or bone marrow as shown.
‘Multi’ is many , therefore adult stem cells are able to be come several different cells of the same type. Such as adult brain stem cells are only ever able to become, say neural cells but they cannot suddently become a bone cell as they are different types of cells. Adults stem cells have an even narrower differention potential than their pluripotent and even totipotent embryonic stem cell counter parts. Dispite this disavantage, they are are more widely accepted as their cultivation does not invole destroying a life. It is also to be noted that embryonic stem cells are leading the way in saving other’s lives, perhaps even to the extent that humans do not require to sacrifice a life to save another life.
Apart from their potential uses, areas such as corneal transplants have been improved significantly. Adult stem cells from the patient’s undamaged cornea are taken and grown in a lab. Once the cells have multiplied to be able to cover the damaged area on the cornea, then the transplant is underway. Patients are able to restore their sight with little possiblity of tissue rejection as conpared to conventional methods of utilising donated corneas.
So after analysing the current stem cell situation, I am hopeful that they will give rise to even more pleasant suprises in the future! I am also curious to know your thoughts on the post after you have read up to this line. Leave a comment down below to share and discuss your own definitions of a ‘person’.
Author – Jiangmin Hou
Jiangmin is a 5th year high school student currently studying five STEM subjects at Scottish Higher level-Mathematics, Physics, Biology, Computer Science and Chemistry. She is interested in pursuing a degree in Medicine after completion of Secondary Education.