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Stem Cell Research FAQs
Scientists believe that stem cell research is the catalyst for a revolution in medicine. It is moving us into the age of regenerative medicine. An age where serious disease and injury will be treated by providing patients with healthy cells to replace “sick” ones, rather than prescribing chemicals (drugs) or replacing entire organs. Understanding the importance of stem cell research and its potential for providing life-saving cures and treatments begins with the basics. Every cell in our body came from a few stem cells that emerge in the first four or five days in an embryo’s development. At this point the embryo is a microscopic cluster of about 150 cells called a blastocyst. Between 30 and 50 of those cells are stem cells that are pluripotent, meaning they have the ability to develop into any of the more than 200 types of cells in our bodies. There are two basic categories of natural stem cells: embryonic stem cells and adult stem cells. Both types of stem cells share two characteristics, 1) The ability to divide and grow into either more stem cells or into specialized cells for blood, muscle, nerves, etc. and 2) as long as we are alive, they act as potential repair kits to fix cells damaged by disease or injury. Embryonic stem cells (ESCs) only exist at the earliest stage of embryonic development -- from four days through 14 days after the egg is fertilized. Embryonic stem cells are unspecialized cells that become specialized. That means that under the proper conditions in the body or in a laboratory, like a blank computer microchip, they are programmed to develop into specific tissues. These primitive cells can be generated in a laboratory dish. For people who have problems with fertility, an egg is fertilized by sperm in a laboratory dish at an in vitro fertilization clinic. Some blastocysts are not used for fertility treatment because they are unhealthy, damaged or in excess of what is needed for family-building. Thousands are routinely discarded by fertility clinics, and it is the ESCs removed from these damaged or surplus embryos that researchers –- with the donors’ written permission -– use for embryonic stem cell research. Under proper conditions, the embryonic stem cells retain the ability to divide and make copies of themselves, apparently indefinitely. After they have duplicated for several months without changing, they are called a stem cell line. By comparison, adult stem cells, also referred to as tissue stem cells, are present in adults, children, infants, umbilical cords and developing fetuses. They are already specialized or differentiated stem cells because they have become blood-forming stem cells or nervous system stem cells or skin stem cells, etc. They are more limited than embryonic stem cells in that they can only form the kind of cell typical of the organ they came from. Adult/tissue stem cells are often multipotent. For example neural stem cells from the brain can multiply and form both neurons (the excitable cells) and glia (supporting cells). Additionally, their capacity to replace themselves is more limited than embryonic stem cells, so there are often fewer cells to work with. Since late 2007, a new type of stem cell has emerged. Scientists were able to create induced Pluripotent Stem (iPS) cells by treating specialized adult cells with genes introduced using viruses. Using this process, those adult stem cells were “induced” or reprogrammed to revert to a pluripotent or embryonic stem cell-like state. The iPS technology holds great promise for use in laboratory research, but much work must be done before iPS cells can be used for human treatments. We are at the very earliest stages of stem cell research and still have a great deal to learn. Stem cell research is giving us a deeper understanding of human biology at the cellular level, helping us understand early human development, allowing us to watch disease develop from its very earliest stages and giving us the ability to test drugs on human tissue so they will be better developed before reaching the open market. For more details about adult, embryonic and iPS stem cells, click here to review information from the University of Michigan Life Sciences Institute. You can also click here for the International Society for Stem Cell Research. Useful Links |
Basic Questions
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