written by: AlyssaAst•edited by: Paul Arnold•updated: 10/18/2012
Scientists and researchers are excited about the healing potential of stem cells. These biological marvels have the ability to grow into specialized cells such as heart and liver cells, and when extracted and grown under the right conditions could be used to repair damaged tissues and organs.
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Stem cells are found within most multi-cellular organisms and are undifferentiated, which means they have not yet grown into a specialized cell type. Their ability to differentiate, that is grow into specialized cells is one of their standout and defining properties. The other is their ability to self-regenerate. To many in the field they are the revolutionary future of medicine, but the research as we shall see later in this guide is not without controversy.
There are two main types of mammalian stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells are found within embryonic tissues (they form during the blastocyst phase); whereas adult stem cells are found throughout the body in many types of tissue. Stem cells have the ability to differentiate into specialized embryonic tissues as an embryo develops, while the stem cells in adults repair and replenish organs and tissues, such as intestinal tissues and blood.
There is feverish activity in labs all over the world as scientists attempt to harness the properties of stem cells for new treatments for some of the diseases that plague us such as Parkinson's, Alzheimer's and heart disease. Some successes have already been chalked up. Common conditions, such as angina, have shown positive results when stem cells have been used as a course of treatment. SCID (severe combined immunodeficiency) is a very rare medical condition, in which babies are born with little or no immune system. A number of stem cells transplants have been carried out which have raised the number of white blood cells, providing the subjects with an effective defense against opportunistic infections. And there are many other promising areas of research.
The ethical issues that surround the use of embryonic stem cells make it difficult for scientists and researchers in some countries to receive the funding they need to pursue their work. The debate over the use of stem cells centers on the destruction of embryos for scientific purposes.
For example, the Catholic Church is fundamentally opposed to the use of stem cells for scientific research, a position once summed up by Pope John Paul II: "Experience is already showing how a tragic coarsening of consciences accompanies the assault on innocent human life in the womb, leading to accommodation and acquiescence in the face of other related evils, such as euthanasia, infanticide, and most recently, proposals for the creation for research purposes of human embryos, destined to destruction in the process. A free and virtuous society, which America aspires to be, must reject practices that devalue and violate human life at any stage from conception until natural death."
The foundation of their argument is derived from the question of when exactly human existence begins. Does it begin at fertilization? Or, does human life get underway 14 to 15 days after embryonic development? Both sides of the debate hold strong arguments, as one side claims the use of stem cells destroys human lives, while the other believes their use can save human lives.
Until both sides can develop a consensus over the use of stem cells, animal stem cells are most commonly used for scientific research. Even with the use of animal derived stem cells, advancements have already been made. Preliminary findings are demonstrating that use of stem cells are beneficial for a variety of conditions, offering a renewed hope for diseases and conditions that were once thought to be crippling and even fatal.