Key Differences Between Embryonic & Adult Stem Cell Research

1. What Are Stem Cells? As the name suggests, all of our 300+ human cell types "stem" from primitive, undifferentiated cells. They are the precursors to the specialized cells that make up our bones, blood, brain cells, heart cells, muscles, skin, organs etc. There are 2 types of stem cells: embryonic and adult. Embryonic stem cells come from the center of the newly fertilized egg within 5 days of fertilization, that is, before it is implanted in the wall of the uterus. It is about the size of sugar grain. This ball of cells is called a "blastocyte". Adult stem cells are found in a variety of tissues after birth (brain, bone, intestine, liver, kidneys, muscle, skin, pancreas and nervous system but not the heart). They function in repair and tissue replacement. They were thought to only be able to repair the tissue from which they originated. 2. Where Do the Fertilized Eggs Come From? The vast majority of embryonic stem cells come from left over fertilized eggs from in vitro fertilization. Couples who use in vitro fertilization (ie, fertilization that occurs outside the body) have more than one egg and sperm fertilized in case implantation back into the female does not take. Approximately 50%-60% of these embryos are considered non-viable. 3. What Is the Controversy About? The Catholic Church believes that life begins at conception therefore any use of this ball of cells is considered murder. The potential of these cells to become human if implanted is given the same status as a viable, fetus. Many Christian sects have adopted this belief as well. Other religious teachings do not share this belief. The concern of the Catholic church is that any use of these fertilized eggs for any purpose except re-implantation is the equivalent of murder. 4. Why Not Use Only Adult Stem Cells for Research? Only embryonic stem cells (not adult stem cells) have the ability to remain in an undifferentiated state indefinitely in culture. Only embryonic stem cells have the capacity to become any type of cell in the body. Adult stem cells have been thought to be less able to change into other cell types from the tissue in which it was found. Recent research has shown that adult stem cells may be more flexible than previously thought. 5. What Are the Main Hurdles in Stem Cell Research? Aside from the political and ethical issues, there are 3 main hurdles: Keeping stem cells undifferentiated in culture Being able to stimulate cell development along a specific path of development into a fully differentiated cell type Devising techniques for reimplantation of differentiated cells to the targeted diseased tissue 6. What Is the Future of Stem Cell Treatment? Scientists have been able to take adult stem cells derived from specific tissues and reverse them into other cell types opening the door to unlimited differentiation. Stem cell research is currently underway for the treatment of Alzheimer's disease, cancer, spinal cord injuries, blood diseases, baldness, skin diseases, neurological diseases, musculo-skeletal disorders, diabetes, liver and kidney disease and deafness to name a few.