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Stem cells are amazing cells that have the remarkable potential or ability to develop into many different cell types in a body during youthful years and perhaps puberty. Stem cells act as an internal repair system which is without limit that repairs and replenishes all other cells in the particular area as long as the body is still alive which represents a huge medical breakthrough for all humanity.
When a particular stem cell divides, it has the potential to remain as a stem cell or to become another different cell with a definite function such as a muscle cell in an arm. Stem cells are different to other cells in the body due to being unspecialized cells capable of renewing themselves through cell division and these stem cells can also regularly divide to repair and replace worn out cells or tissues. Adult stem cells or somatic cells have been identified in many organs and tissues including the brain, bone marrow and blood vessels.
Types of Stem Cells
Today, scientists mainly use two different stem cells, namely, embryonic stem cells and non-embryonic somatic cells or the general name, body cells. Stem cells are extremely important for living organisms because the new embryo which is called a blastocyst creates the foundation for the entire structure of an organism, including many cell types and organs such as the heart.
Stem cells offer new and modern potential for the treatment of many diseases such as diabetes and various heart diseases. This potential of stem cells creates a multitude of ethical beliefs and opinions in which the validity and ethics are tried and tested.
Properties of Stem Cells
Stem cells are not similar at all to other cells in any organism. Stem cells have the amazing ability and sophisticated properties to divide and renew themselves for extremely long periods. These stem cells are completely unspecialized and they can create any specialized cell type in an organism which is living.
All stem cells are unspecialized which means that these stem cells do not have any tissue-specific structures that can allow it to perform and master any specialized functions. When unspecialized stem cells give rise to specialized cells, this process is called differentiation. While differentiating, the actual cell goes through several stages or transformations, becoming more specialized with every stage, until they are completely specialized.
Adult stem cells or somatic cells create or generate the cell types of the tissue in which they reside. Embryonic stem cells are derived from embryos. Most embryonic stem cells are derived from embryos that are developed from eggs that have been fertilized in an in vitro fertilization clinic and then are normally donated for scientific research with intimate consent from the donor.
Embryonic Cell development
These stem cells are not derived from eggs fertilized in a woman's body. The actual embryos from which human embryonic stem cells are derived are normally four or five days old and are simply microscopic hollow ball of cells called a blastocyst.
This blastocyst is made up of three main structures called the trophoblast, which is a layer of cells that surrounds the blastocoels which is a hollow cavity inside the actual blastocyst. The last structure is called the inner cell mass, which is a group of cells at one end of the blastocoels that develops into the embryo.
Embryonic cells grown from a laboratory
The growing of stem cells in a laboratory environment is called cell culture. The stem cells known as embryonic stem cells are isolated by transferring the inner cell mass into a plastic laboratory culture dish or petri dish that contains a nutrient broth know as culture medium. The stem cells divide and spread over the surface of the culture dish. The process of generating an embryonic stem cell line is quite inaccurate and as a result lines are not produced each time an inner cell mass is placed into a cultured petri dish.
If the inner cell mass cells survive and start to actually divide and multiply enough to completely fill the dish, the cells are carefully and very slowly removed and are then placed into another waiting culture dishes. This process of subculturing is repeated many times.
How are embryonic stem cells stimulated to differentiate?
If the embryonic stem cells in the culture are grown under appropriate and watchful conditions, they can remain unspecialized or undifferentiated. If the stem cells are allowed to weave together they will start to differentiate immediately. These cells can then form muscle, nerve and other cell types.
To create specific types of cells, scientists control the embryonic cells. The scientists watch over the chemical composition, alter the surface area of the dish or modify the cells by inserting unique genes into it. If it is possible to direct the embryonic cells, humanity may be able to treat diseases in the present and future.
Similarities and differences between Somatic and Embryonic stem cells
Embryonic and adult stem cells each have their own pros and cons regarding potential use. One big difference is their different abilities in the number and type of unspecialized cell types that they can become. Embryonic stem cells are easily grown in culture while somatic cells are rare in mature or old tissues.
Potential of Embryonic stem cells
There are many different ways to actually use stem cells in research. Doing precise studies of the human embryonic stem cells will be able to yield complex and intriguing information about many complex issues that occur during human development. A main goal of this specific work is to identify how undifferentiated stem cells become the specific differentiated cells that form specific tissues and organs.
Scientists have discovered that turning specific genes on and off are central to the process and success. Medical conditions like cancer and many birth defects are due to abnormal cell division. Controlling the cell division requires more study and testing to be successful.
Human stem cells can also be used to test new drugs. New and different types of medication can be tested for safety on differentiated cells that are generated from human pluripotent cell lines. Cancer cell lines are used to screen potential anti-tumor drugs. The availability of pluripotent stem cells would allow drug testing in a wider range of cell types. Scientists will have to be able to precisely and accurately control the differentiation of stem cells into specific cell types on which these drugs are tested.
The utmost and most important potential application of human stem cells is the ability of the stem cells to generate tissues that can be used for cell based therapies. In modern times donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs outweigh the availability of the supply.
Human stem cells which are directed to differentiate into specific cell types, offer the amazing possibility of a completely renewable source of replacement cells and tissues to treat diseases including most spinal cord injuries, strokes, diabetes and many more diseases.
Human stem cells have the ability to differentiate into any possible type of cell and because of this stem cells offer something in the development of medical treatments for an extremely wide range of conditions and diseases. Various treatments such as a treatment for physical trauma, degenerative conditions and genetic diseases can be used but there are staunch ethical beliefs on the matter of stem cells.
In early 2009, the FDA approved the first human clinical trials using embryonic stem cells. Some stem cell researchers are busy working to try to develop new techniques of isolating stem cells that are as potent as embryonic stem cells, but do not actually need a human embryo.
Stem cell research is a controversial issue, because with the present state of technology, the actual creation of a human embryonic stem cell requires the forceful destruction of a human embryo. The many debates and arguments have motivated the pro-life movement, whose members are concerned with the rights and status of the embryo as a human life.
Pro-life believe that embryonic stem cell research violates the sanctuary of human life and is tantamount to murder. Many Medical researchers widely submit that stem cell research has the amazing potential to dramatically alter and change approaches to understanding and treating diseases. The anticipated medical benefits of stem cell research add powerful urgency to these many debates.
In August, 2000, The U.S. National Institutes of Health's Guidelines stated:
"research involving human pluripotent stem cells...promises new treatments and possible cures for many debilitating diseases and injuries, including Parkinson's disease, diabetes, heart disease, multiple sclerosis, burns and spinal cord injuries. The NIH believes the potential medical benefits of human pluripotent stem cell technology are compelling and worthy of pursuit in accordance with appropriate ethical standards."
In 2006, researchers at Advanced Cell Technology of Worcester, Mass., succeeded in obtaining stem cells from mouse embryos without destroying the embryos. If this technique and its reliability are improved, it would alleviate some of the ethical concerns related to embryonic stem cell research.
Another technique announced in 2007 may also defuse the longstanding debate and controversy. Research teams in the United States and Japan have developed a simple and cost effective method of reprogramming human skin cells to function much like embryonic stem cells by introducing artificial viruses.
While extracting and cloning stem cells is complex and extremely expensive, the newly discovered method of reprogramming cells is much cheaper. However, the technique may disrupt the DNA in the new stem cells, resulting in damaged and cancerous tissue. More research will be required before non-cancerous stem cells can be created.
Austria, Denmark, France, Germany and Ireland do not allow the production of any human embryonic stem cell lines, but the creation of embryonic stem cell lines is allowed in Finland, Greece, the Netherlands, Sweden and the United Kingdom.
When the actual Fetus is a threat to life one may kill someone who is unjustly pursuing a third party to kill him. The Mishna clearly states that if the life of a woman in labor is threatened by her fetus, the fetus should be aborted. But once a portion of the baby has emerged, we may not abort the fetus, because "one may not set aside one person's life for the sake of another."
The principle behind this ruling is that one may kill someone who is unjustly pursuing a third party to kill him. Since the fetus, which is not yet considered a "complete" person, is "pursuing" the mother in a way that will inevitably result in her death, we may kill it first.
While stem cells can be derived from aborted fetuses and even adults, easily the best source for stem cells is the small clump of cells that compose the early zygote only a few days following contraception. The debate continues to rage around the ethical debates to allow the destruction of pre-embryos to obtain stem cells for research that may save thousands of lives.
Human stem cells have the impressive ability to differentiate into every cell of the human body. If it is possible to manipulate the conditions controlling cellular differentiation, we might be able to create replacement cells and organs that can cure diseases and illnesses such as diabetes and Alzheimer's disease.
The ultimate promise of stem cell research would be to combine it with cloning. The mere possibility of cloning a person's cells is extraordinary, but instead of allowing the cloned cell to develop into a fetus, we can place it into the appropriate environment that will cause it to differentiate into whichever cell that will be virtually genetically identical to that person's cells. If a person needs a liver transplant the stem cells can be transplanted into that person without the deadly risk of rejection and also without the need for anti-rejection drugs.