What Are Stem Cells ?Cells are the basic unit of our bodies. Our bodies are made up of trillions of cells much like a thriving city is made up of millions of people. Taking the analogy further, people are coming and going, doing their everyday things, working jobs that keep the city going. And many people are dying in this city too. And just like people in a city, cells in our bodies are dying all the time too. For instance, thousands of blood cells die everyday and need to be replaced. Just like the people in a bustling city need to be replaced quite literally by “new blood” or the city as a whole would grind to a halt and die, the same applies to the body. The role of creating “new blood”, and every other cell in our body for that matter, is performed by stem cells. Without stem cells the body would grind to a halt and die.
Types Of Stem CellsThere are two types of stem cells, adult stem cells and embryonic stem cells. Adult stem cells are different to embryonic stem cells in that they can only create specialized new cells. For instance, stem cells that create blood cells can only create types of blood cells. Skin stem cells can only create skin cells. And so on. Whereas embryonic stem cells can create any type of cell in the body if genes within the cells direct them to. So by learning how to direct these stem cells to take certain actions, scientists can create heart cells, brain cells, liver cells and all sorts of other cells that make up tissue in the body. So, as you can imagine, adult stem cells are interesting to scientists because they determine how we appear to rejuvenate part of our bodies. Understanding how they work and how they appear to slow down or “run out” as we get older can teach us more about the aging process. However, embryonic stem cells are even more interesting because they promise to reveal how scientists can grow any cells and tissues of the body.
The applications of this are clear.[caption id="attachment_2268" align="aligncenter" width="330"] Thanks to Wikipedia for the image. ;)[/caption] If you could grow a new heart and transplant it into a person with a diseased heart they could live a longer life. In fact, as more is learned about how to direct the stem cells to develop, all the vital organs of the body could be replaced as they age or wear out. It would be like taking your car in for a service, only it's your body that is getting the service. Of course this is still science fiction as scientists do not know how to grow complete organs from embryonic stem cells. And there are other problems, like successfully transplanting the new organs into a body without them being rejected. But as more research continues many of these issues are being tackled. So a “60 year total body overhaul” could be part of our future and ensure that people live for a longer time than previously thought possible. But even though this “spare part” world is yet to be realized, there are other applications of being able to grow human cells and tissue. For instance, stem cells grown in a tube or dish could be used in drug trials. If a new cholesterol reducing drug had been developed, it could be applied to the stem cells that had been developed into heart or blood vessel cells. Drug makers could evaluate the results as if the trial was being done on a human. This would bypass animal testing and potentially speed up the process of a drug being available to the public.
Ethical Issue To Stem Cell ResearchSo this is an exciting field of research in biological and medical science but there is an ethical consideration, especially with embryonic stem cells. Embryonic stem cells are taken from the inner cell mass of a blastocyst. A blastocyst is a human embryo four to five days after a human egg has been fertilized by sperm. By taking the inner cell mass, scientists are destroying the fertilized human embryo.
Therein lies the ethical issue. Does this embryo have human rights ? Is it a living person ? Are scientists committing murder ?For this reason, many parts of the world, like the United States, have laws against using embryonic stem cells. Regardless of your stance on the ethical issue, this is holding back development and advancement in this field of research and is a source of frustration for people that would like to use embryonic stem cells.