Emory neurosurgeon Robert Gross was recently quoted in a Tennessee newspaper article about a clinical trial of cell therapy for stroke. He used cautionary language to set expectations.

“We’re still in the very early exploratory phases of this type of work,” Gross told the Chattanooga Times Free Press. “In these cases, a significant area of the brain has been damaged, and simply putting a deposit of undifferentiated cells into the brain and magically thinking they will rewire the brain as good as new is naive. None of us think that.”

A more preliminary study (just 18 patients) using the same approach at Stanford and University of Pittsburgh was published this summer in Stroke, which says it was the “first reported intracerebral stem cell transplant study for stroke in North America.” The San Diego Union Tribune made an effort to be balanced in how the results were described:

Stroke patients who received genetically modified stem cells significantly recovered their mobility… Outcomes varied, but more than a third experienced significant benefit.

The newspaper articles made us curious about what these cells actually are. They’re mesenchymal stromal cells, engineered with an extra modified Notch gene. That extra gene drives them to make more supportive factors for neurons, but it doesn’t turn them into neurons. The Stroke paper says that the cells are expected to survive for just one month in the body, based on experience in animal models. Mesenchymal stromal cells are the same type of cells tested by the Emory Personalized Immunotherapy Center for the treatment of autoimmune diseases.

For stroke, surgeons inject the modified cells in multiple places around the damaged area of the brain. Note that the study is planned for patients who had their strokes at least six months ago, after which recovery of mobility typically levels off.

The previously published study was not placebo-controlled – the current one is, and Gross explains why that’s important:

Emory’s Gross emphasized that neither the patients nor their doctors need to know whether or not they actually receive the drug. Previous studies have shown that if patients know they were given a drug, they will tend to say they believe it helped them, whether it actually did or not.

The critical test: whether participants who do get cells see improvements in their motor function. The company sponsoring the studies, SanBio, appears to be interested in trying the same cells with other disorders such as Parkinson’s.

In Emory’s Department of Anesthesiology, Ling Wei and Shan Ping Yu have been investigating similar cell therapy approaches for stroke in experimental models.