Cells are the structural and functional units of all living organisms. Basically, there are three types of cells make up the mammalian body. Somatic cells which make up most of our bodies, most of these cells are diploid (except RBCs as they have no nuclei). Germ cells are any line of cells that give rise to gametes (eggs and sperms) and stem cells which have the ability to divide for indefinite periods and give rise to specialized cells (National Center for Biotechnology information).What are stem cells? Stem cells are master cells of the body, i.
e. hey are the cells from which all other cells with specialized functions are created. Under proper conditions, in the human body or the lab, stem cells divide to many cells called daughter cells, these cells may either become new stem cells (self-renewal) or become specialized (differentiated) to cells with special functions (e. g.
blood or brain cells). No other cell of the human body has such a possibility to renew or differentiate. Sources of stem cells are multiple; embryonic stem cells come from embryos of 4-5 days old (blastocyst).These are Pluripotent stem cells i.
e. hey can divide into more stem cells or differentiate and become any type of body cells, so they have the highest potential for use to regenerate or repair diseased tissues or organs. Adult stem cells are found in a small number of adult tissues (e. g.
bone marrow), also in placentas and umbilical cords. Other types of stem cells include embryonic germ cells, which are stem cells that come from an area in the embryo or fetus destined to be ovaries or testis. Researchers have also discovered stem cells in amniotic fluid and were able to identify stem cells that could develop into several other types of cells (retrieved from; Mayo clinic. om).
A stem cell line is a group of cells which all descend from a single original stem cell. Cells in a stem cell line keep dividing but do not differentiate into specialized cells. In this way, they remain free from genetic defects (retrieved from Mayo clinic. com). Large number of embryonic stem cells can be relatively easy grown in culture, while adult stem cells are rare in mature tissues and methods of increasing their number in artificial culture have not yet worked out fully.Despite that, using adult stem cells in replacement therapy carries the advantage of using the patient’ own cells (retrieved from <http://stemcells.
nih. gov/>). Growing cells in the laboratory is known as cell culture. Human embryonic stem cells are isolated by transferring the inner cell mass into a plastic laboratory culture dish that contains a nutrient broth known as culture medium. The cells divide and spread over the surface of the dish. The inner surface of the culture dish is typically coated with mouse embryonic skin cells that have been treated so they will not divide.
This coating layer of cells is called a feeder layer. The reason for having the mouse cells in the bottom of the culture dish is to give the inner cell mass cells a sticky surface to which they can attach. Also, the feeder cells release nutrients into the culture medium. Recently, scientists have begun to devise ways of growing embryonic stem cells without the mouse feeder cells. This is a significant scientific advancement because of the risk that viruses or other macromolecules in the mouse cells may be transmitted to the human cells (<http://stemcells. nih.
gov>).Why embryonic cell research is important? There are three basic opportunities presented by embryonic stem cell research. First; research could lead to the development of innovative replacement or transplantation therapies for diseases such as diabetes or heart diseases, what is currently known as regenerative medicine. Second; this research can provide scientists with deeper information of cell differentiation and development as it is believed that turning genes on and off is key to the process of differentiation with possible consequences on diseases as cancer and congenital anomalies.Thirdly; stem cells could be used as a substitute in the screening and testing of drugs, that is to test new medications for safety on differentiated cells generated from a human Pluripotent cell lines (JDRF position paper P. 3).
For decades, researchers have been studying the biology of stem cells to figure out how development works and to find new ways of treating health problems. Because stem cells can give rise to any tissue found in the body, they provide nearly limitless potential for medical applications.Current studies are researching how stem cells may be used to prevent or cure diseases and injuries such as Parkinson’s disease, type 1 diabetes, heart disease, spinal cord injury, Duchene’s muscular dystrophy, Alzheimer’s disease, strokes, burns, osteoarthritis, rheumatoid arthritis, vision, and hearing loss. Stem cells could also be used someday to replace or repair tissue damaged by disease or injury. Stem cell procedures currently provide life-saving treatments for patients with leukemia, lymphoma, other blood disorders, and some solid tumors.
