A stroke is one of the most common diseases, affecting almost 800,000 people annually in the United States. Recent research on mesenchymal stem cells has shown them to be potentially effective at treating strokes and improving the conditions of stroke patients. Mesenchymal stem cells can help by secreting growth factors to aid other recovery mechanisms such as neurons, synapses, and new blood vessels. In this article, we discuss stem cell therapy for stroke recovery and how stem cells can be used to help patients recover from strokes.
What are Stem Cells?
Stem cells are undifferentiated cells that are defined by two key characteristics: the ability to become multiple types of cells and the ability to proliferate indefinitely. Stem cells can be found in many parts of the body, including the brain, bone marrow, blood vessels, skin teeth, gut, and liver.
What is a Stroke?
A stroke is a condition that occurs when a blood vessel carrying oxygen and nutrients to the brain is blocked by clots or ruptures. There are three main types of strokes:
- Ischemic stroke
- Hemorrhagic stroke
- Cryptogenic stroke
Ischemic Stroke
The most common type of stroke is known as an ischemic stroke, accounting for 85% of stroke cases. An ischemic stroke occurs when the blood supply to part of the brain is reduced or interrupted, thus preventing the brain from receiving necessary oxygen and nutrients.
Hemorrhagic Stroke
A hemorrhagic stroke occurs when blood from an artery suddenly begins to bleed into the brain. This damages the brain and prevents the part of the body controlled by the damaged part of the brain from working properly.
Cryptogenic Stroke
A cryptogenic stroke is a stroke that occurs without a known cause. Cryptogenic strokes usually involve an artery to the brain becoming blocked by a blood clot, but the underlying cause of these strokes is often unknown.
How Does Stem Cell Treatment for Stroke Work?
After a stroke occurs, millions of brain neurons die within minutes—cut off from the oxygen and nutrients they need to survive. While dead brain neurons cannot be revived, some tissue around the dead areas remains functional. Research has shown that stem cells can help rejuvenate and replenish still-functioning areas in the brain. Stem cells can either be injected directly into the brain or arteries and blood vessels to then travel to the brain. Mesenchymal stem cells, having the capacity to differentiate into many different types of cells, can prevent ongoing cell death which usually occurs after a stroke.
Although mesenchymal stem cells cannot differentiate into brain cells to replace those lost by stroke, they are still able to provide healing through the production of proteins and molecules. Before stem cells were first used to treat strokes, doctors and researchers assumed mesenchymal stem cells would provide healing by differentiating into different cell types. However, they soon discovered that mesenchymal stem cells help by secreting growth factors which aid other recovery mechanisms such as neurons, synapses, and new blood vessels. Stem cell therapy does generate new cells within the brain, rather it helps make current cells more effective at healing and rebuilding the brain and body.
Stem Cell Therapy for Stroke Recovery
Recovering from a stroke looks different for every patient. Immediately after a stroke, patients can experience paralysis, difficulty speaking, numbness, and pain. According to the National Stroke Association, two out of every three stroke survivors have lingering conditions and disabilities. Stem cell therapy most effectively treats strokes when used in conjunction with other therapeutic methods. While stem cells are still being tested in clinical trials to prove their efficacy, results so far have been promising.
A small clinical trial conducted by Stanford University School of Medicine tested the effects of stem cell therapy on 18 stroke victims with an average age of 61. Stem cells were transplanted directly into the patient’s brain. Within months, the patients registered an average increase of 11.4 points on the Fugl-Meyer Assessment, a stroke-specific, performance-based impairment test.
Future of Stem Cell Treatment for Stroke
The use of stem cells for treating strokes has shown encouraging results and great promise for future research and development. There are several clinical parameters and general practices that need to be determined including the type of stem cells to be administered, the timeline for stem cell administration, and the method of administration. If stem cell therapy is shown to be increasingly effective for stroke victims, it is possible that stem cells could be mass-manufactured and shipped to hospitals to become more available as a form of treatment.
Summary
A stroke is a medical emergency that occurs when there is a loss of blood flow to part of the brain. After a stroke occurs, millions of brain neurons die within minutes, cutting off oxygen and nutrients. Research and clinical trials have shown mesenchymal stem cells to be potentially effective in helping patients recover from strokes. Stem cell therapy may be used to improve recovery, prevent ongoing cell death, and increase neurological function in those who have had a stroke.
