Early clinical trial results suggest that stem cell therapy that uses the patient’s own cells could be effective for treating stroke and spinal cord injury well after the initial damage occurs, researchers at Sapporo Medical University in Japan have said. Their description of research into this approach appears in the TRI publication Principles of Regenerative Medicine.
Each year, just under 300,000 people in Japan experience a stroke, many of whom either die or are left with serious disabilities such as paralysis and brain damage. Currently, the most effective treatment is administered in a very short period after a stroke has occurred. After that, treatment is limited to rehabilitation.
Successful results from stem cell transplantation experiments in animal models of stroke prompted a clinical study led by researchers at Sapporo Medical University, who were supported by the Translational Research Center for Medical Innovation (TRI) in Japan. They took bone marrow samples from 12 patients who had received treatment for acute stroke. The researchers then cultured stem cells with the patients’ own serum and injected them once into a peripheral vein up to 133 days after the stroke. Significant changes in symptoms and magnetic resonance imaging (MRI) measurements were seen within 1–2 weeks after transplantation, with most patients showing reduced paralysis after 1–3 days. MRI showed that affected brain regions recovered quickly even when treated more than 6 weeks after the stoke onset, demonstrating that treatable brain tissue remained.
According to Osamu Honmou from Sapporo Medical University School of Medicine, cell therapy has multiple mechanisms of action, operating at different sites and different times. Stem cells accumulated in the damaged tissue, where they exerted neuroprotective and anti-inflammatory effects, limiting further neural damage. They also induced axons to regenerate and grow, and contributed to recovery of blood flow to the brain. Furthermore, the stem cells enhanced the plasticity of the whole brain.
Spinal cord injury poses similar challenges. An estimated 5,000 people suffer a spinal cord injury in Japan each year. After initial surgery and drug therapy, treatment focuses on making the best use of remaining function, rather than recovering lost function.
Promising results in rat models of spinal cord injury led to a phase II, open-label, exploratory trial in patients with cervical cord injury. The researchers hope this treatment will actively repair the damaged spinal cord by delaying secondary injury and facilitate neural recovery and regeneration.