Stroke continues to be one of the top causes of long-term disability and death worldwide. Stroke treatments currently are aimed at restoring blood flow and managing post-stroke symptoms, but there is an increasing interest in the field of regenerative medicine — more specifically stem cell therapy — as a potential game changer in recovery from stroke. But do stem cells truly help stroke victims recover lost functions? Let’s look at what we know so far.
What is a stroke and how does it affect the body?
A stroke happens when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Brain cells start to die within minutes. The two general kinds of stroke are ischemic stroke (caused by a blood clot blocking a vessel) and hemorrhagic stroke (caused by bleeding in the brain).
Stroke survivors frequently struggle for years to come with detailed issues ranged from paralysis to lack of ability to speak, remember things or emotional well-being. Although acute care has improved, few options exist for repairing the brain after a stroke. It is here that stem cell therapy presents a potential solution.
What Are Stem Cells?
Stem cells are unique cells that can develop into many different cell types in the body. They can split and rejuvenate and can, given the proper conditions, become specialized cells like neurons or muscle cells. There are multiple types of stem cells that are being investigated for stroke recovery:
- Embryonic stem cells (ESCs): Potent and can differentiate into any cell type, but are controversial.
- Adult stem cells: Present in organs such as bone marrow and fat. Because mesenchymal stem cells (MSCs) are the most prevalent stem cells tested for use in stroke trials.
- These include induced pluripotent stem cells (iPSCs) — adult cells that have been reprogrammed to an embryonic-like state.
How Stem Cells May Aid Stroke Recovery
Stem cells restore stroke recovery through multiple mechanisms:
1. Neuroprotection
Stem cells could protect brain cells that are in imminent danger of dying after a stroke. They can release growth factors that lessen inflammation and cell death.
2. Neurogenesis and Cell Replacement
Certain types of stem cells can become neural cells. They can replace damaged or dead neurons, helping to restore function in affected parts of the brain.
3. Angiogenesis
Increased blood flow to the injured brain tissue is facilitated by the angiogenesis-promoting effects of stem cells.
4. Immune system modulation
The immune system response after a stroke can worsen damage. Stem cells potentially can modulate this response and lessen secondary injury.
What the Research Says
In the last two decades, several animal studies and early-phase clinical trials have evaluated stem-cell treatment to promote recovery from stroke. Here’s what scientists have discovered:
Promising Preclinical Results
For example, mouse studies have demonstrated improved motor function and repair of damaged areas in the brain following the treatment with stem cells. These studies paved the way for human trials.
Early Human Trials
Preliminary clinical trials involving a variety of stem cells, including mesenchymal stem cells (MSCs) and neural stem cells, have yielded promising results. Some studies have found improvements in mobility, speech and daily activities, especially when therapy occurs within weeks or months of a stroke.
One of the more notable studies, the PISCES trial in the UK, used neural stem cells injected directly into the brain. Some of the participants even showed modest functional gains, years after their strokes.
Safety First
Trials have generally found stem cell treatments to be safe and well-tolerated, with relatively few serious side effects. But long-term safety data is still pending.
Limitations and Challenges
There are no effective medications to aid in stroke recovery, though researchers are studying stem cell therapy. Several challenges remain:
- Timing: The timing of stem cell therapy is still being researched.
- Delivery Method: Intravenous injection, intra-arterial delivery or injection directly into the brain, each with advantages and disadvantages.
- Standardization: Stem cell sources, doses and treatment protocols varied across the studies.
- Efficacy: No two patients respond the same way — some see little or no benefit.
Stem Cells Evolve as Stroke Therapy: New Directions
Regenerative medicine is a fast-moving field. There are clinical trials ongoing testing new kinds of stem cells, ways to deliver them and combinations with other therapies (such as rehabilitation or brain stimulation). Personalized medicine approaches — tailoring treatment to the individual — might also improve outcomes.
With more evidence, researchers are optimistic that stem cell therapy could be a go-to option for stroke survivors. But patients must not seek unproven or unregulated treatments, which may carry grave risks.
What Do Stroke Survivors Need to Know?
If you or a loved one is recovering from a stroke, here are a few important points:
- Ask your doctor about clinical trial opportunities and whether stem cell therapy may be a possibility in the future.
- Stay informed. The field is evolving, with new therapies potentially entering the market over the next few years.
- Focus on rehabilitation. Physical therapy, occupational therapy and speech therapy are the mainstays of stroke recovery.
Conclusion
Although stem cell therapy for stroke recovery remains experimental as of now, most preliminary studies are demonstrating a lot of potential. Stem cells, whether they are transplanted into the brain or released from transplanted tissue, will protect brain cells, and they may even help to regenerate new brain cells, giving stroke rehabilitation a new lease on life. While clinical trials are still ongoing, closer to unlocking their full potential.