Bone Marrow Stem Cells Promising for Stroke

A new analysis of published research in the April 8, 2014, issue of Neurology suggests that stem cells from bone marrow may be beneficial in recovery from stroke, say researchers from the University of California, Irvine’s Sue and Bill Gross Stem Cell Research Center.

Steven Cramer, MD, Weian Zhao, PhD, and colleagues identified 46 published studies that examined the use of mesenchymal stromal cells (MSCs), a type of multipotent adult stem cell mostly processed from bone marrow and used in animal models of stroke.

“Stroke remains a major cause of disability, and we are encouraged that the preclinical evidence shows [MSCs’] efficacy with ischemic stroke,” Cramer said in a statement. “MSCs are of particular interest because they come from bone marrow, which is readily available, and are relatively easy to culture. In addition, they already have demonstrated value when used to treat other human diseases.”

The researchers concluded that MSCs are significantly better than control therapy in 44 of 46 studies. The effects of the MSCs on functional recovery were robust whatever the dosage used, the time MSCs were administered relative to stroke onset, or the method of administration. In fact, the cells helped recovery even when given one month after stroke and whether they were injected directly into a blood vessel of introduced directly into the brain. The investigators say that MSCs trigger repair mechanisms and limit inflammation.

MSCs do not differentiate into neural cells; normally they transform into bone, cartilage, and fat cells. However, Dr. Cramer noted that they are like an “inducible pharmacy on wheels and as good immune system modulators, not as cells that directly replace lost brain parts.”

The study found that MSCs have consistently improved multiple outcome measures with very large effect sizes, in a high number of animal studies. Therefore, the investigators conclude that the findings should be the foundation of further studies on the use of MSCs in the treatment of ischemic stroke in humans.

“In contrast to meta-analyses of preclinical data for other stroke therapies, higher-quality MSC preclinical studies were associated with larger behavioral gains,” the researchers wrote. “These findings support the utility of further studies to translate MSCs in the treatment of ischemic stroke in humans.”