The Study of Stem Cells
Among all the recent, developing medical technology, stem cells are receiving the most global attention. This advanced technology is very effective in theory, yet they have not yet been approved for actual use. However, a few days ago I came across an article stating that a paralyzed man had recovered from paralysis due to stem cells. Knowing that stem cells relate somewhat to the field of orthopedic surgery, I decided I must learn more about stem cells in order to be more knowledgeable of orthopedic surgery as a whole.
Stem cells are body cells that have no set task. While one may think that there is nothing special about these cells, the fact that they have no individual task sets them apart from all other cells. This is because these stem cells can grow, differentiate, and specialize in any task. This means that by harvesting them and surgically implementing them into the necessary area, these stem cells can replace the previously damaged cells. Furthermore, these cells have practically no limit to the amount of cell division they can perform, meaning that as long as the organism they inhabit is alive, they can replenish its cells. A bit of my own opinion, I believe that the term ‘stem cell’ derives from this function; this cell serves to stem and create cells . While this treatment was hypothesized in 1981, the method to harvest these cells took the world by surprise in 1998. These fascinating cells can be extracted from three places: bone marrow, adipose (fat) tissue, and blood. However, each of these locations require a vastly different method of cultivation.
One thing to note is that while these procedures are known as the stem cell transplants, the patient can donate to their own body. The stem cells coming from bone marrow requires a surgeon to drill into the bone and then extract the marrow. Furthermore, the bone marrow cannot be extracted anywhere; it is usually from the femur, commonly known as the thigh bone, and the iliac crest, the upper portion of the pelvis. The marrow is then transplanted either harvested or transplanted into the person who requires the marrow, hence the name bone marrow transplant. The one thing to note is that while this procedure is not obsolete, it is now more common to collect stem cells from blood, redubbing the procedure the ‘stem cell transplant’. As for stem cells that originate from adipose tissue, a procedure known as liposuction is done. As the name states, the procedure is accomplished by removing any extra fat, or lipid, from under the skin via suction. Different from the bone marrow transplant, the adipose tissue, is simply harvested, researched, and cultivated into a specific organ. The last method of extraction is to get stem cells from blood. This process is known as apheresis, the separation of blood into its different parts. This is because blood is created from bone marrow that can be used as stem cells, and therefore it contains components that make it a stem cell. Furthermore, the blood is segmented into its three main parts: leukocytes, extracellular matrix, and erythrocytes, or in layman’s terms, white blood cells, plasma, and red blood cells. The stem cells are then extracted from the separated blood and used for either research, or transfer. Out of all the methods of stem cell extraction, obtaining it from blood it the most safe and efficient, and therefore it is the most used.
Another big separation stem cells have is whether they are ‘adult’ or ‘embryonic’. An embryonic stem cell originates from an early-stage embryo. Adult stem cells originate from developed humans whose cells have already specialized and have their own functions. The main difference between these two cells is in the two functions that stem cells perform; the ability to specialize and the ability to indefinitely perform cell division. The embryonic stem cell, because it is one of the true originating cells, can specialize much faster and better than adult stem cells. In comparison, adult stem cells, because they have been performing cell division for much longer than other cells, have a stronger cell division cell division ability. Another difference is that to this very day, there is no approved treatments that involve the usage of embryonic stem cells. Meanwhile, the usage of adult stem cells in various treatments is recognized as the cells are simply harvested from a large nest of stem cells. This is mainly due to the fact that to harvest an embryonic stem cell, an embryo must be destroyed. However one must realize that embryonic stem cells are not derived from a female’s fertilized egg. The methods of extraction listed in the above paragraph all pertain to the adult stem cells as those are found in the developed human body. In order to extract the embryonic stem cell, a donor must willingly donate her preimplanted embryo, an embryo that has not been set in place in the female’s uterus. The unfertilized embryo is then placed into a glass tube or container containing some sort of nutrient agar. Then a sperm cell is placed inside the same container to artificially fertilize the embryo. This form of fertilization is known as in vitro fertilization, meaning that the embryo is fertilized in a container inside a laboratory. After being fertilized, the egg then implants itself into the nutrient agar. The embryonic cell is also coated with ‘feeder layer’ that allows the cell to grow without going through cell division. Like this, the newly grown embryonic cell can be harvested and then reimplanted into another agar plate. While the embryo does not have to go through the preimplantation stage again, the embryonic cells are placed into several fresh culture dishes over the span of many months and many subculture cycles to grow a satisfactory amount of embryonic cells.
Although all these amazing things have been said about the stem cell, there are still quite a few obstacle in understanding and utilizing them to their fullest potential. The first problem is the process of differentiation and specialization. This is one of the two main functions of stem cells, and while it is such an important aspect of the cell, there is no complete understanding behind it. It is known that in order for cells to differentiate, various genes must be expressed, while others must be repressed. However, playing with the expression of genes is a dangerous game as very malignant conditions, especially cancer, are caused by cell division and differentiation going haywire. Only by doing more research into the gene expression that causes cell division, differentiation, and cancer itself can researchers hope to understand more about stem cells. By completely understanding gene expression, eventually it can be controlled, meaning that stem cells can grow to become the organs that one desires. Another big problem is the supply of stem cells. While every developed human body contains stem cells, overall these stem cells are very rare to harvest. This is because it is not known if stem cells can carry diseases or conditions that the original owner has had or may have been a carrier of. Furthermore, there are millions upon millions of stem cells making up an organ, and while its cell division may be indefinite, it does require much time and effort to grow a completely independent organ inside a laboratory. Therefore, the most realistic use of (adult) stem cells is to replace damaged tissue and allow it to grow back by itself. As seen in the article I referred to at the very top, the usage of these cells allowed the paralyzed patient to regain some control over his appendages.
While I am not undermining this amazing achievement, in comparison to growing another organ made completely from stem cells, the former seems much more feasible.
Stem cells are recognized as one of the most important types of research worldwide. In the close past it treated parts of various cancers. A short period it partially cured a man of his paralysis. With its eventual development, eventually new organs can be made, meaning that donors don’t have to sacrifice their own organs for the sake of others. For all we know, maybe the human body can be remade or even enhanced. However, the future of medical technology will slowly uncover with the passage of time, and all we can do is delve into the field as far as we can.
“Paralyzed Man Regains Use Of Arms And Hands After Experimental Stem Cell Therapy At Keck Hospital Of USC | USC Stem Cell | USC”. Stemcell.usc.edu. N. p., 2017. Web. 25 Jan. 2017.
National Institutes of Health. U.S. Department of Health and Human Services, n.d. Web. 26 Jan. 2017.