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Stem cells are cells that could become any other cell in the human body, from muscles to brain, to blood. Because of this ability, it's believed that they could be used in the treatment of several conditions.
There are two types of stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells are found in undeveloped embryos (unused embryos from in vitro fertilization are often donated to science and used in research), and it's these stem cells that can turn into more than one type of cell. That’s how we develop in the womb – our stem cells transforming into the different cells of our bodies.
The second type of stem cell, adult stem cells, are found in fully-developed tissues such as the brain and skin. If we want these adult cells to transform into a different kind of cell, they must be manipulated in a lab. There's no adult stem cell yet found that can develop into every kind of cell as embryonic ones can.
In recent years, stem cell therapies have emerged as a potential treatment for several conditions such as Alzheimer's disease, paralysis, and Lyme disease. Currently, the only stem cells used to treat illness are adult stem cells that form blood cells. These are found in the bone marrow and are used in the treatment of leukemia.
New research has now shown that stem cells may help to prevent, and even reverse, opioid tolerance in patients using opioids for pain management.
Opioids are in widespread use across the country for patients with chronic pain, with prescriptions increasing rapidly year-on-year and opioid-related deaths on the rise. Long-term opioid use can lead to patients developing a tolerance, and their pain worsening as a result. This is a phenomenon called opioid-induced hyperalgesia or OIH. Patients suffering from OIH find that their pain medication simply stops having an effect. This leads many to increase their dose to get the same effect of their previous lower dose, but this can be dangerous. There's a risk of overdose and other side effects. Limiting the development of OIH would reduce the risk of patients over-medicating themselves.
To prevent patients from developing OIH and to limit the risk of accidental overdose, clinicians and researchers working in the field have begun trials using stem cells. These stem cells have been found to suppress brain inflammation and have a profoundly positive effect on opioid tolerance and OIH. Trials using rats and mesenchymal stem cells showed that the cells prevented the rats from developing the conditions and reversed it in rats already showing symptoms.
The signs are good, and stem cell therapy has huge potential to ease the suffering of many opioid-tolerant patients. The next step is to seek FDA approval for human trials, and after that, who knows? There's much work to be done, but it's entirely possible that stem cell treatments for opioid tolerance are only a few years away.