Neural stem cells (NSCs)
Neural stem cells (NSCs) are specialized stem cells found exclusively in the central nervous system, with a primary role in developing into neurons and glial cells. They are crucial for transmitting information and supporting neuronal function. Discovered in humans in 1998, NSCs are more prevalent in developing fetuses and children, with a limited number present in specific adult brain regions, such as the hippocampus and striatum. While some NSCs remain dormant, others are poised to generate new neurons when needed, particularly in response to brain injuries or conditions like strokes.
Research into NSCs is ongoing, with the hope of harnessing their regenerative potential to treat various neurological conditions. For instance, studies suggest that NSCs can target damaged areas in the brain, potentially aiding recovery after a stroke. However, challenges such as the harvesting of NSCs, their delivery to injury sites, and their effectiveness in certain diseases like Alzheimer's and Parkinson's complicate their therapeutic use. Ethical considerations also arise surrounding the sourcing of stem cells, particularly those derived from embryos, fueling debate about the implications of such research. Overall, while promising, the application of NSCs in medicine remains in the experimental stage, with further research needed to unlock their full potential.
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Neural stem cells (NSCs)
Neural stem cells are a subtype of stem cells that occur specifically in the central nervous system. Stem cells form the basis of all the cells in the body. They are formed as non-specific cells, then differentiate into a wide variety of cells. Embryonic stem cells are the very first cells formed when a zygote develops. These cells are very versatile and can become anything the body needs them to be. Adult stem cells usually have much less power for differentiation. They can become things that the body regularly needs to replenish, like blood cells and skin cells, but they cannot become anything and everything as an embryonic stem cell can. Neural stem cells occur only in the nervous system. They become neurons, which transmit information, or one of two kinds of glial cells, which protect neurons and help transmit their signals quickly and efficiently.
Background
Researchers discovered human neural stem cells in 1998. Like all stem cells, these are more abundant in developing fetuses, babies, and children than they are in adults. However, adults seem to have a limited number of neural stem cells in certain parts of the brain. These parts include the spinal cord, the striatum (an area that pertains to processing movement), the hippocampus (an area connected to forming and maintaining memories), the hypothalamus (an area that focuses on maintaining the body’s automatic systems, such as respiration), the septum (an area that helps process emotions), and the olfactory bulbs (an area that interprets and processes smell). Some of the neural stem cells in adults seem to be dormant, while others seem to be waiting for times when the brain needs to generate new neurons.
Research into neural stem cells, how they work, and when, where, and how they can be used in the brain is relatively new and ongoing. As researchers learn more, the hope is that these cells may be used to help people heal from traumatic brain injuries, strokes, concussions, and other conditions. Challenges to these uses include problems with harvesting neural stem cells, getting them to the right places in the brain, and ensuring they work to repair any damage that has been done. Additionally, neural stem cells seem limited in what they can do for people with some conditions, such as Parkinson’s and Alzheimer’s diseases. In these cases, researchers are looking at whether and how these cells could be reactivated or reawakened.
Overview
Researchers have learned that neural stem cells seem to have an affinity for the places in the brain where damage has been done. Whether they are harvested from the person receiving them or harvested from someone else and encouraged to grow in a lab, they seem to target the location that was damaged or injured. The person’s own internal neural stem cells will try to do the same, though certain conditions or certain types of damage can hamper their movement. Because neural stem cells stay relatively hidden in the brain, researchers are looking into drugs or other treatments that might activate them when they are needed. This could potentially help enhance their movement toward the injury, putting even more stem cells in a place where they are ready and able to help repair damage.
One area of promising research regarding neural stem cells is recovery after a stroke. During a stroke, a lack of oxygen can cause cell death in parts of the brain. If the stroke is treated early, long-term damage may be minimal. However, if it is not treated early, and sometimes even when the person receives care quickly, long-term damage can be extensive. Researchers have begun to have success helping people heal at least some stroke damage both by stimulating internal neural stem cell activity and by introducing neural stem cells cultured in the lab. While this research is promising and has helped some patients, it has a long way to go before it can be widely available and useful for all or most people who have had strokes.
Additional research is ongoing regarding neural stem cells and epilepsy, Parkinson’s disease, Alzheimer’s disease, spinal cord damage, and other forms of brain disease and damage. Neural stem cell treatments are only available to those participating in a research study or occasionally as last-ditch attempts to save a person’s life.
A major controversy over stem cells has to do with where and how they are harvested. Stem cells that come from embryos (human eggs that have been fertilized by sperm) are the most versatile and work the best when it comes to regeneration in the brain. However, creating embryos so researchers and medical staff can harvest their stem cells creates an ethical problem. Because the embryo does not survive, some people believe that this procedure kills a human being or a potential human. Others believe that these embryos are not human or that their sacrifice is worthwhile because of the healing these cells offer. Furthermore, some people object to the use of stem cell lines that originated from aborted fetuses, though the original cells ceased to exist decades ago.
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