Stem Cells Implanted on Heart Surface Help Repair Hearts After Myocardial Infarction

A collaborative study between bioengineers and surgeons at Rice University and Baylor College of Medicine has demonstrated that shielding stem cells improves the cells' ability to heal heart injuries caused by heart attacks. The results were published in Biomaterials Science.

In a study using mouse models, the researchers created capsules of wound-healing mesenchymal stem cells (MSCs) and implanted them next to wounded hearts through minimally invasive techniques. They found that within four weeks, the heart-healing rate was 2.5 times greater in animals treated with shielded stem cells than those treated with nonshielded stem cells. 

"What we're trying to do is produce enough wound-healing chemicals called reparative factors at these sites so that damaged tissue is repaired and restored, as healthy tissue, and dead tissue scars don't form," says co-author Omid Veiseh.

 Ravi Ghanta—co-lead author—says that while prior studies have shown that MSCs can promote tissue repair after a heart attack, in clinical trials "cell viability has been a consistent challenge.” "Many of the cells die after transplantation," he says. "Initially, researchers had hoped that stem cells would become heart cells, but that has not appeared to be the case. Rather, the cells release healing factors that enable repair and reduce the extent of the injury. By utilizing this shielded therapy approach, we aimed to improve this benefit by keeping them alive longer and in greater numbers."

The hydrogel biomaterial was developed as a way to work around the immune system’s response to encapsulation technologies, "The immune system doesn't recognize our hydrogels as foreign, and doesn't initiate a reaction against the hydrogel," Veiseh explains. "So we can load MSCs within these hydrogels, and the MSCs live well in the hydrogels. They also secrete the same reparative factors that they normally do, and because the hydrogels are porous, the wound-healing factors just diffuse out. With further development, this combination of biomaterials and stem cells could be useful in delivering reparative therapy to heart attack patients," he concludes.