Stem cells are a specific type of unspecialized cells that are present in almost all multicellular organisms. They possess two characteristic properties viz. self-renewal and potency. By self-renewal, we mean, stem cells can undergo cell-division multiple times and regenerate themselves. Potency is the ability to develop into other types of cell. Because of these properties, stem cells play a significant role in medical therapies, especially in the treatment of certain chronic diseases and disorders.
Stem Cell Research
This research is focused on the two mammalian stem cell types, namely, the embryonic stem cells and adult (non-embryonic) stems cells. In the former case, the stem cells are isolated from the inner cells of the 3-5 day old embryo the 'blastocysts'; whereas, adult stem cells are isolated from adult tissues. The embryonic stem cells are totipotent (omnipotent) and can develop into any type of cell. In an adult body system, the adult stem cells act as a means to repair and replace the damaged cells. It is to be noted that adult stem cells are less flexible than embryonic ones and can develop into a few cell types.
Nowadays, adult stem cells, isolated from the bone marrow and umbilical cord blood, are utilized for potential treatment of diseases such as diabetes, heart disease and Parkinson disease. In recent times, many parents opt for umbilical cord blood storage technique, as a security for the child. This technique of storing cord blood is performed following a child's birth.
An Overview of The Controversy in Stem Cell Research
The first embryonic stem cells were isolated from mouse embryos in 1981. Recently, in 1998, human embryonic cells were isolated. These stem cells are cultured in laboratory and used for infertility treatments. With the consent of the parents, the excess in vitro fertilized (IVF) embryos are either stored in liquid nitrogen or discarded.
The process of isolating of human embryonic stem cells from blastocysts cause the death of the embryos. This is the main reason for the controversy. According to pro-lifers, embryo formed after the fertilization of an ovum and a spermatozoon is a human. They opposed the idea of destroying an embryo by isolating stem cells. Thus, they are against embryonic stem cells research. They claim that killing an embryo is a form of homicide and is punishable under certain jurisdictions.
However, many people are of the opinion that a human embryo is not actually a person. There is no doubt that an embryo can develop into a human, but is not a sentient by itself, as it does not have organs. Hence, according to them, stem cell research is ethical, as it has wide applications for the betterment of the people.
Following this controversy, embryonic stem cells are not used in any of the treatment methods as of now. The use of embryonic stem cells has other challenges like lack of research funds, transplant rejections and chances of unpredictable differentiation and developing tumors. Compared to embryonic stem cells, adult stem cell research is less controversial, as they can be isolated without affecting the individual.
Speaking about the embryonic stem cells, researchers opined that they are the most potential candidate for universal application and treatment of human degenerative diseases. Overall, this research enables scientists to understand the concept of cell properties and the replacement of damaged cells with healthy cells. This way, advancement in medical science will help in the study of genetic disease and development of more potential treatment methods.