Stem+Cell+Research

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=== ﻿﻿Stem Cell Research﻿: The Embryonic Report  === Author: Matthew Yuen﻿  December 7th, 2010﻿﻿  ﻿ ﻿   Abstract:   This report will summarize the different types of stem cells with an emphasis on embryonic stem cells, how we acquire them, and replicating them in the lab. Stem cell research has been around for some time now, and not many people really understand how they really work down in the microbial level. Stem cell research has been around for generations now with numerous people against the idea, yet many of the people against it have no real idea of how it works at the cellular level. People are unaware of what is happening, thus assuming that it is bad without any real information on it. This report will help anyone who is unfamiliar with the topic of stem cell research and how it works at the molecular level.

Introduction: Stem cell research is something that has been in many topics lately, and many people ask me personally of what I think of stem cell research. Outside of only knowing that stem cells help humans with diseases, the only information I have is from comedy television shows and skewed views from other people that stem cells are bad or good. I had no real knowledge of the topic for myself before hand. This project was a good opportunity for me to focus on the molecular part of stem cell research and figure out what is really happening.The stem cell is essentially the main tool used to make up the human body (Weiss 2010). Stem cells are capable of dividing for long periods of time, are unspecialized, but can develop into specialized cells. The earliest stem cells in the human body are found in the human embryo, and later in the human life there are other stem cells found in certain adult cells (National Institutes of Health 2009). When I had read about the stem cells inside an embryo, the most interesting information I found was that any stem cell from a human embryo will eventually give rise to every cell, tissue, and organ that eventually is a human adult (Watson, Freudrich 2004). When it divides, it can make any one of the 200 different cells in the human body. Stem cells also have the capability to reproduce themselves many times over (Weiss 2010). This information I found most helpful in understanding the basics of stem cell research, and finding what i really wanted to focus and go in depth at the microbial level of stem cell research.

Discussion: **﻿The d ifferent types of stem cells:** ﻿﻿There are a few different types of stem cells used in stem cell research. There are embryonic stem cells, adult stem cells, and induced pluripotent stem cells (Mosna, Luc, Mauro 2010). Embryonic stem cells include those found within the embryo, the fetus or the umbilical cord blood (Watson, Freudrich 2004). Depending upon when they are harvested, embryonic stem cells can give rise to just about any cell in the human body (Watson, Freudrich 2004). Adult stem cells can be found in infants, children and adults. They reside in already developed tissues such as those of the heart, brain and kidney. They usually give rise to cells within their resident organs (Mosna, Luc, Mauro 2010). The induced pluripotent stem cells are adult stem cells, differentiated cells that have been experimentally reprogrammed into a stem cell like state (Watson, Freudrich 2004). Both the adult stem cells and induced pluripotent stem cells at some point were in fact embryonic stem cells back when they were at a more primal state. With this idea, it can be thought that all stem cell research originates at the embryonic stage.  Most embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in-vitro in an in-vitro fertilization clinic and then donated for research purposes with informed consent of the donors. They are not embryos from eggs fertilized in a woman's body (National Institutes of Health 2009). Once the coupling of a sperm and egg in in-vitro, the fertilized egg starts to divide forming an embryo. At this stage it is a clump of 4-8 early embryonic stem cells (National Institutes of Health 2009). These stem cells are said to be totipotent, meaning they can divide and differentiate into any type of cell in the body and essentially form the entire organism; however these are not the cells scientists are most interested in. (National Institutes of Health 2009) After about 5-7 days of development the embryo becomes a blastocyst, which is a hallow ball of cells. The outside layer of cells forms the placenta. On the inside lies a mass of about 30 stem cells called the inner mass cells, also known as embryonic stem cells. These inner mass cells are said to be pluripotent, meaning they can divide and differentiate into almost any type of cell (National Institutes of Health 2009).



<span style="color: #000000; font-family: 'Comic Sans MS',cursive;">**<span style="color: #000000; font-family: 'Comic Sans MS',cursive;">﻿ How we aquire the stem cells for research:** <span style="font-family: 'Comic Sans MS',cursive;">Once an egg cell is fertilized by a sperm, it will divide and become an embryo. In the embryo, there are stem cells that are capable of becoming all of the various cell types of the human body (Sa 2009). Scientists obtain embryos in two ways, by the process of in-vitro fertilization and therapeutic cloning (Watson, Freudrich 2004). In in-vitro fertilization, a couple's sperm and eggs are fertilized in a culture dish. The eggs develop into embryos, which are then implanted in the female. However, more embryos are made than can be implanted. So the extra embryos are usually frozen and shelved (Watson, Freudrich 2004). Usually most couples donate their unused embryos for stem cell research. The second way in which scientists get embryos is therapeutic cloning. This technique merges a cell from the patient who needs the stem cell therapy, with a donor egg (Watson, Freudrich 2004). The nucleus is removed from the egg and replaced with the nucleus of the patient's cell. This egg is stimulated to divide either chemically or with electricity, and the resulting embryo carries the patient's genetic material, which significantly reduces the risk that his or her body will reject the stem cells once they are implanted (Watson, Freudrich 2004). <span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: left;">When an embryo contains about eight cells, the stem cells are totipotent; they can develop into all cell types. At 3 to 5 days, the embryo develops into a ball of cells called a blastocyst. A blastocyst contains about 100 cells total and the stem cells are inside. At this stage, the stem cells are pluripotent; they can develop into almost any cell type (Watson, Freudrich 2004).

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<span style="color: #000000; font-family: 'Comic Sans MS',cursive;">**<span style="color: #000000; font-family: 'Comic Sans MS',cursive;">﻿ Replicating stem cells in a lab:** <span style="font-family: 'Comic Sans MS',cursive;">Growing and replicating cells in the laboratory is very similar to growing bacteria in a microbiology class. Human embryonic stem cells are generated by transferring cells from an embryo into a plastic laboratory culture dish that contains a nutrient broth known as a culture medium. The cells divide and spread over the surface of the dish (Watson, Freudrich 2004). In order to isolate these stem cells for research purposes, the scientist will use a microscopic needle to suck the embryonic stem cells out of the blastocyst (Mosna, Luc, Mauro 2010). These stem cells are then cultivated on special cell culturing plates and can grow indefinitely. This means that one embryo with 30 inner mass cells can produce thousands upon thousands of embryonic stem cells. However, it also means that this embryo will never develop into a human (National Institutes of Health 2006, pg 27-35).media type="youtube" key="-FfO_3xyrmU?fs=1" height="385" width="480" align="right"

<span style="font-family: 'Comic Sans MS',cursive;">The inner surface of the culture dish is typically coated with mouse embryonic skin cells that have been treated so they will not divide. The coating layer of cells is called a feeder layer (National Institutes of Health 2006, pg 27-35). The mouse cells in the bottom of the culture dish provide the cells a sticky surface to which they can attach. The feeder cells also release nutrients into the culture medium. Researchers have devised ways to grow embryonic stem cells without mouse feeder cells (National Institutes of Health 2006, pg 27-35). This scientific advancement may soon replace using mouse cells because of the risk that viruses and other macromolecules in the mouse cells could be transmitted to the human cells.

<span style="font-family: 'Comic Sans MS',cursive;">If the plated cells survive, divide and multiply enough to crowd the dish, they are removed gently and plated into several fresh culture dishes. The process of re-plating or sub-culturing the cells is repeated many times and for many months(National Institutes of Health 2006, pg 27-35). Each cycle of sub-culturing is referred to as a passage. Once the cell line is established, the original cells yield millions of embryonic stem cells. At certain points during the process of generating embryonic stem cell lines, scientists test the cells to see whether they exhibit the properties that make them embryonic stem cells. This process is called characterization (National Institutes of Health 2006, pg 27-35).

<span style="font-family: 'Comic Sans MS',cursive;">As long as the embryonic stem cells in the culture are grown under appropriate conditions, they can remain unspecialized. If the cells are allowed to clump together, they begin to differentiate spontaneously. They can form muscle cells, nerve cells, and many other cell types. Spontaneous differentiation is a good indication that a culture of embryonic stem cells is healthy; it is not an efficient way to produce cultures of specific cell types however (National Institutes of Health 2006, pg 27-35).To generate cultures of specific types of differentiated cells; heart muscle cells, blood cells, or nerve cells, scientists try to control the differentiation of embryonic stem cells. They change the chemical composition of the culture medium, alter the surface of the culture dish, or modify the cells by inserting specific genes. From any certain change it can essentially result in any one of the 200 different cells in the human body (Weiss 2010). With this in mind, anything can truely be possible in the field of health with the help of stem cells.

Literature Cited:

 * Mosna, Federico, Luc Sensebe, and Mauro Krampera. "Human bone marrow and adipose tissue mesenchymal stem cells: Academic Journal. //Stem// a user's guide. //Cells and Development// 19.10 (2010): 1449+. //Health Reference Center Academic//. Web. 6 Dec. 2010. []


 * National Institutes of Health. 2006. “Stem Cells: A Primer.” In //The Stem Cell Controversy: Debating the Issues Second Edition//, edited by Michael Ruse and Christopher A. Pynes, 27-35. Amherst: Prometheus Books.


 * National Institutes of Health, U.S. Department of Health and Human Services, 2009 Stem Cell Basics: Introduction . In //Stem Cell Information// Bethesda, MD: [cited Monday, December 06, 2010] Available at []


 * <span style="display: block; line-height: normal; margin: 0in 0in 10pt; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto;"> Sa, Sasha. "Terry » Archive » FAQ – Stem Cells (Sa Mix) August 7th, 2009." //Terry// . N.p., n.d. Web. 6 Dec. 2010. []>.


 * Watson, Stephanie, and Craig Freudenrich, Ph.D. "How Stem Cells Work" 11 November 2004. HowStuffWorks.com. []> 04 December 2010.


 * <span style="display: block; line-height: normal; margin: 0in 0in 10pt; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto;"> Weiss, Rick . "Stem Cell Research Article, Embryonic Cells Information, Cell Therapy Facts -- National Geographic." //Science and Space Facts, Science and Space, Human Body, Health, Earth, Human Disease - National Geographic//. N.p., n.d. Web. 6 Dec. 2010. <http://science.nationalgeographic.com/science/health-and-human-body/human-body/stem-cell-divide.html#page=1>.