What are stem cells?
Stem cells are the body's raw materials — cells from which all other cells with specialized functions are generated. Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells. These daughter cells either become new stem cells (self-renewal) or become specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle or bone. No other cell in the body has the natural ability to generate new cell types. Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell. Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions. Scientists have for the first time used adult human stem cells to “cure” rats with Parkinson’s disease, a neurodegenerative illness that currently has no cure. The study, published in the current issue of STEM CELLS Translational Medicine, details how a team of researchers working in Germany at the University of Bielefeld (UB) and Dresden University of Technology were able to produce mature neurons using inferior turbinate stem cells (ITSCs). ITSCs are stem cells taken from tissue that would generally be discarded after an adult patient undergoes sinus surgery. The team then tested how the ITSCs would behave when transplanted into a group of rats with Parkinson’s disease. Prior to transplantation, the animals showed severe motor and behavioral deficiencies. However, 12 weeks after receiving the ITSCs, the cells had migrated into the animals’ brains and functional ability was not only fully restored, but significant behavioral recovery was witnessed, too. In another positive sign, no tumors were found in any of the animals after the transplantations, something that also has been a concern in stem cell therapy.Due to their easy accessibility and the resulting possibility of an autologous transplantation approach, ITSCs represent a promising cell source for regenerative medicine,” said UB’s Barbara Kaltschmidt, Ph.D., who led the study along with Alexander Storch, M.D., and Christiana Ossig, M.D., both of Dresden University. “The lack of ethical concerns associated with human embryonic stem cells is a plus, too.” “In contrast to fighting the symptoms of Parkinson’s disease with medications and devices, this research is focused on restoring the dopamine-producing brain cells that are lost during the disease,” said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. "These cells are easy to access and isolate from nasal tissue, even in older patients, which adds to their attraction as a potential therapeutic tool.” What are stem cells? Stem cells are a renewable source of tissue that can be coaxed to become different cell types of the body. The best-known examples are the embryonic stem (ES) cells found within an early-stage embryo. These cells can generate all the major cell types of the body (they are “pluripotent”). Stem cells have also been isolated from various other tissues, including bone marrow, muscle, heart, gut and even the brain. These “adult” stem cells help with maintenance and repair by becoming specialized cells types of the tissue or organ where they originate. For example, special stem cells in the bone marrow give rise to all the various types of blood cells (similar blood cell-forming stem cells have also been isolated from umbilical cord blood). Adult vs. embryonic stem cells Because adult stem cells become more committed to a particular tissue type during development, unlike embryonic stem cells, they appear to only develop into a limited number of cell types (they are “multipotent”). What are induced pluripotent stem cells? In addition to ES cells, induced pluripotent stem (iPS) cells, discovered in 2007, represent an important development in stem cell research to treat diseases like Parkinson’s disease. Essentially, iPS cells are ”man-made” stem cells that share ES cells' ability to become other cell types. IPS cells are created when scientists convert or "reprogram" a mature cell, such as a skin cell, into an embryonic-like state. These cells may have potential both for cell replacement treatment approaches in patients and as disease models that scientists could use in screening new drugs. IPS cell technology is somewhat related to a previous method called somatic cell nuclear transfer (SCNT) or “therapeutic cloning” (the technology that gave us Dolly the Sheep). Unlike the iPS cell approach, which converts adult cells directly into stem cells, SCNT involves transferring the genetic material of an adult cell into an unfertilized human egg cell, allowing the egg cell to form an early-stage embryo and then collecting its ES cells (which are now genetic “clones” of the person who donated the adult cell). To date, however, this has not been successfully demonstrated with human cells and iPS cell methods may be replacing SCNT as a more viable option. A potentially exciting use for iPS cells is the development of cell models of Parkinson’s disease. In theory, scientists could use cells from people living with Parkinson’s disease to create iPS cell models of the disease that have the same intrinsic cellular machinery of a Parkinson’s patient. Researchers could use these cell models to evaluate genetic and environmental factors implicated in Parkinson’s disease. Stem cells: What they are and what they do. Stem cells and derived products offer great promise for new medical treatments. Learn about stem cell types, current and possible uses, ethical issues, and the state of research and practice. You've heard about stem cells in the news, and perhaps you've wondered if they might help you or a loved one with a serious disease. You may wonder what stem cells are, how they're being used to treat disease and injury, and why they're the subject of such vigorous debate. Here are some answers to frequently asked questions about stem cells. Why is there such an interest in stem cells? Researchers and doctors hope stem cell studies can help to:
What are stem cells? Stem cells are the body's raw materials — cells from which all other cells with specialized functions are generated. Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells. These daughter cells either become new stem cells (self-renewal) or become specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle or bone. No other cell in the body has the natural ability to generate new cell types. Where do stem cells come from? Researchers have discovered several sources of stem cells:
Embryonic stem cells are obtained from early-stage embryos — a group of cells that forms when a woman's egg is fertilized with a man's sperm in an in vitro fertilization clinic. Because human embryonic stem cells are extracted from human embryos, several questions and issues have been raised about the ethics of embryonic stem cell research. The National Institutes of Health created guidelines for human stem cell research in 2009. Guidelines included defining embryonic stem cells and how they may be used in research and donation guidelines for embryonic stem cells. Also, guidelines stated embryonic stem cells may only be used from embryos created by in vitro fertilization when the embryo is no longer needed. Where do these embryos come from? The embryos being used in embryonic stem cell research come from eggs that were fertilized at in vitro fertilization clinics but never implanted in a woman's uterus. The stem cells are donated with informed consent from donors. The stem cells can live and grow in special solutions in test tubes or petri dishes in laboratories. Why can't researchers use adult stem cells instead? Although research into adult stem cells is promising, adult stem cells may not be as versatile and durable as are embryonic stem cells. Adult stem cells may not be able to be manipulated to produce all cell types, which limits how adult stem cells can be used to treat diseases. Adult stem cells also are more likely to contain abnormalities due to environmental hazards, such as toxins, or from errors acquired by the cells during replication. However, researchers have found that adult stem cells are more adaptable than was initially suspected. What are stem cell lines and why do researchers want to use them? A stem cell line is a group of cells that all descend from a single original stem cell and is grown in a lab. Cells in a stem cell line keep growing but don't differentiate into specialized cells. Ideally, they remain free of genetic defects and continue to create more stem cells. Clusters of cells can be taken from a stem cell line and frozen for storage or shared with other researchers. What is stem cell therapy (regenerative medicine), and how does it work? Stem cell therapy, also known as regenerative medicine, promotes the reparative response of diseased, dysfunctional or injured tissue using stem cells or their derivatives. It is the next chapter of organ transplantation and uses cells instead of donor organs, which are limited in supply. Researchers grow stem cells in a lab. These stem cells are manipulated to specialize into specific types of cells, such as heart muscle cells, blood cells or nerve cells. The specialized cells can then be implanted into a person. For example, if the person has heart disease, the cells could be injected into the heart muscle. The healthy transplanted heart cells could then contribute to repairing defective heart muscle. Researchers have already shown that adult bone marrow cells guided to become heart-like cells can repair heart tissue in people, and more research is ongoing. Have stem cells already been used to treat diseases? Yes, doctors have performed stem cell transplants, also known as bone marrow transplants. In stem cell transplants, stem cells replace cells damaged by chemotherapy or disease or as a way for the donor's immune system to fight some types of cancer and blood-related diseases, such as leukemia. These transplants use adult stem cells or umbilical cord blood. Researchers are testing adult stem cells to treat other conditions, including a number of degenerative diseases such as heart failure. What are the potential problems with using embryonic stem cells in humans? To be useful in people, researchers must be certain that stem cells will differentiate into the specific cell types desired. “Durham, NC (PRWEB) December 05, 2014 By Mayo Clinic Staff Migraines with aura in middle age linked to Parkinson's disease By Trisha Henry, CNN updated 5:06 PM EDT, Wed September 17, 2014 Researchers don't yet understand why migraines might be linked to Parkinson's disease. (CNN) -- People who suffer from migraines with aura during middle age have double the risk of developing Parkinson's disease or other movement disorders later in life than those who do not, according to a study published Wednesday in the journal Neurology. Migraines are the most common brain disorder in both men and women, according to the World Health Organization, and one of the top 10 most debilitating conditions. Aura is the term used to describe the feelings and symptoms that happen shortly before and during a migraine. "Roughly one-third of affected individuals can predict the onset of a migraine because it is preceded by an 'aura,' visual disturbances that appear as flashing lights, zig-zag lines or a temporary loss of vision," according to the National Institutes of Health. Researchers followed more than 5,000 people between the ages of 33 and 65 for 25 years, who were originally enrolled in a clinical trial designed to study heart disease in Iceland. The participants were interviewed about migraine symptoms in middle age and then, about 25 years later, asked about Parkinson's disease symptoms. They were also asked about symptoms for a related disorder called Restless Legs Syndrome. The results were based on the study participants' self-reported diagnoses, though in the majority of the cases researchers confirmed the diagnoses by looking at medical records and the participants' medication use. Parkinson's disease, depression linked? Former NFL great on concussions Boxing coach opens up about Parkinson's "The patients in this study were not carefully examined and definitely diagnosed with Parkinson's disease," said Dr. Michael S. Okun, national medical director of the National Parkinson Foundation, which is why he believes more research is needed before drawing any conclusion that the two are related. "Head trauma and other neurological issues can manifest with symptoms similar to Parkinson's disease and future studies will need to better control for these factors." Compared to those without headaches, people in the study who suffered from migraines with aura in middle age were about twice as likely to have been diagnosed with Parkinson's disease when the researchers checked back. They were also more likely to report at least four symptoms commonly associated with Parkinson's disease later in life. Parkinson's-like symptoms were also more common in those with migraine without aura, though the link was not as strong, lead study author Ann Scher told CNN in an email. Scher, a professor of epidemiology at Uniformed Services University in Maryland, wants to make sure people understand the actual risk of Parkinson's disease in people with migraine is still very low. Researchers don't yet understand why migraines might be linked to Parkinson's disease or other movement disorders, Scher says. They don't believe that the link is due to medications taken to treat migraines, some of which block dopamine. Nor do they think that the link is due to related brain diseases, "since we controlled for these factors." Possible explanations for the connection, she agrees, might be a previous head injury or a shared genetic risk factor that increases the risk for both migraine and Parkinson's disease. One common link may be abnormalities in dopamine production and dopamine receptors in the brain, said Okun. Some groups suggest the same dopamine treatment that helps Parkinson's patients may also help with migraines. "Another theory is that in migraine sufferers there seems to be a higher deposition of metals, such as iron, in the brain and specifically in areas important to movement," said Okun. "Some experts believe that this metal deposition may place patients at risk for diseases like Parkinson's." For more information on Migraines you may go to the
NINDS www.ninds.nih.gov/Disorders/All-Disorders/Migraine-Information-Page Neurology Times http://www.neurologytimes.com/headache-and-migraine/therapies-migraine-prophylaxis?rememberme=1&elq_mid=1781&elq_cid=1821004 Neurology Times http://www.neurologytimes.com/headache-and-migraine/new-hope-migraine-patients?rememberme=1&elq_mid=1781&elq_cid=1821004&GUID=CFAE9BC1-E1FC-489B-8D65-69E03ECFAEB5 Laser Eye Surgery HUB https://www.lasereyesurgeryhub.co.uk/migraine-types-triggers-treatments/ |