Stem Cells: A Promising Treatment for Stroke

SadaNews - Scientists have discovered that transplanting brain cells derived from stem cells can offer benefits that go beyond mere survival after a stroke, according to a report by SciTechDaily.

Restoring Blood Vessels

According to new research conducted by the University of Zurich and the University of Southern California, stem cell treatment helped mice recover from strokes by rebuilding damaged brain connections, repairing blood vessels, and improving movement.

These results raise hopes that future therapies may one day contribute to repairing stroke damage, which is currently considered permanent.

Long-Term Disability

Stroke remains a leading cause of long-term disability worldwide, as when blood flow to a part of the brain is interrupted, oxygen-deprived cells die within minutes.

Unlike skin or bones, the brain's ability to replace lost tissue is limited, leading many survivors to face lifelong paralysis, speech problems, or memory loss.

Neuronal Progenitor Cells

Researchers have spent years looking for ways to help the brain rebuild itself. In the new study, the researchers used neuronal progenitor cells, which are early-stage cells capable of developing into different types of brain tissue. These cells were derived from induced pluripotent stem cells, which are adult human cells that have been reprogrammed to resemble stem cells.

One Week Post-Injury

During the research, the team implanted these cells into the brains of mice one week after they suffered a stroke. This timing proved to be critical. In previous transplant attempts, the success rate was low because the injured brain was still suffering from inflammation and toxic chemical signaling. Waiting several days allowed the conditions to stabilize enough for the implanted cells to grow. Researchers were surprised by the emergence of new neurons and rebuilt connections.

Cells Regulating Neural Activity

Over five weeks, the implanted cells survived, spread into adjacent brain tissues, and primarily matured into functional neurons. Many developed into GABAergic neurons, which are specialized inhibitory brain cells that help regulate neural activity and whose numbers significantly decrease after a stroke. These cells are crucial for balancing brain signaling, preventing over-excitation, and coordinating movement.

Communicative Cells

The implanted neurons did not simply exist alongside the damaged brain tissues. Evidence indicated that these cells actively communicated with their surrounding cells through molecular signaling systems associated with neural growth, synapse formation, and tissue repair. Researchers identified several key pathways involved in this interaction, including signals linked to rebuilding neural networks and directing axons to reconnect. Stem cell treatment also appeared to stimulate a broader healing response throughout the injured brain.

Blood-Brain Barrier

Mice that received the transplants developed significantly more blood vessels near the site of the stroke, improving circulation in the damaged tissues. The treatment also reduced inflammatory activity and enhanced the blood-brain barrier, which is the protective membrane that typically prevents harmful substances from leaking into the brain from the bloodstream. Damage to this barrier is a major factor in swelling and exacerbating injury after a stroke.

Researchers also observed an increase in the growth of nerve fibers around the damaged area. Some of the implanted neurons extended into regions associated with movement and sensory control, suggesting that the new cells may have begun to integrate into existing brain circuits, leading to improvements in movement and coordination.

Other Regenerative Processes

Christian Taknenberg from the Institute of Regenerative Medicine at the University of Zurich stated: "The results show that neural stem cells form new neurons while also stimulating other regenerative processes."

Several types of stem cell therapies have reached the initial stages of clinical trials on humans for treating neurological diseases, including Parkinson's disease, and stroke could become one of the next primary targets.