We never would have expected two years or more out that patients could recover from a stroke. We thought the circuits were dead. Now we know they’re still viable.
That encouraging soundbite by Stanford’s Dr. Gary Steinberg in Monday’s Health Day News is based on his team’s preliminary, unpublished results of a stem cell-based clinical trial for treating stroke. The trial is the first of its kind in North America, according to an American Association of Neurological Surgeons press release.
A stroke is a brain attack that occurs when blood flow to the brain is blocked either by a clot or a ruptured blood vessel. This attack disrupts the delivery of nutrients and oxygen to the brain and leads to cell death. Depending on the area of the stroke, survivors may lose their ability to speak, swallow, move their body, or recall memories. It is a leading cause of death, killing 130,000 people each year in the U.S., according to the National Stroke Association. There are about 7 million stroke survivors in the US over the age of 20.
Steinberg’s clinical trial was motivated by the many encouraging animal studies that have shown the promise of stem cells to improve stroke symptoms. In fact, a report in this week’s issue of Neurology by Drs. Steven Cramer and Weian Zhao of UC-Irvine’s Sue & Bill Gross Stem Cell Research Center, showed in 44 out of 46 preclinical animal studies that mesenchymal stem cells (MSCs) helped heal the damage wreaked by stroke.
In the Steinberg-led trial, MSCs isolated from the bone marrow of unrelated donors were injected into the brains of 18 people who had suffered strokes. The main goal of the study was to ensure safety of the injections. Three patients experience adverse events (bleeding, seizure, pneumonia) related to the surgery and they all recovered.
In addition to the good safety profile, all patients showed some signs of improvement. Two patients, both women, had dramatic recoveries. In describing one of the two patients, Dr. Steinberg told Health Day News that:
The 71-year-old could only move her left thumb. She couldn’t move the arm or hand and could barely get her leg off the bed. The day after surgery, she was lifting her arm over her head, and lifting her leg off the bed. She’s walking now. She was wheelchair-bound before.
The other patient, a 33 year-old, regained movement of her paralyzed arm as well as had improvement in her speech. Steinberg was careful to not draw too much from such phenomenal recoveries. He pointed out that these types of responses are far from typical. Also, the trial was not designed to include a “control” group; that is, patients who did not receive the stem cell injections. So it’s difficult to say with full assurance that the improvements were caused by the stem cells themselves or something about the surgical procedure, or something spontaneous that would have occurred without any intervention.
Still Dr. Cramer, who was not part of the study, is encouraged:
It’s a small, early human study. It takes multiple steps to get to something clinically useful, and this is a nice, early step.
He also gave his take on how these mesenchymal stem cells work their magic, which appears not to be a replacement function:
What these cells seem to do instead is to modulate repair processes. They don’t replace the damaged brain so much as massaging the bits that are left, to get maximum function out of them.
What is very clear is that these results justify larger trials with more patients using this MSC-based therapy approach. In addition, Steinberg also has a $20 million CIRM-funded Disease Team grant that aims to test embryonic stem cell-derived neuronal cells in stroke patients. This project’s goal is to file an Investigational New Drug (IND) application with the Food and Drug Administration (FDA), a requirement to begin clinical trials.
With these multi pronged approaches to tackling disease, hopefully researchers will find the most safe and effective therapies sooner and help the millions who are stricken by the devastating effects of stroke.
For more information about CIRM-funded stroke research, visit our stroke fact sheet.