attacks are a leading cause of death, largely because the damage caused by one can lead to more later. Now researchers at Rice University have developed a new way to repair heart tissue and reduce scarring, by implanting capsules loaded with stem cells.

When a person suffers a heart attack, the organ repairs itself as best it can, patching up the damage with scar tissue. The problem is that scarred heart tissue doesn’t beat as well, which throws the rhythm out of whack and eventually leads to further complications down the track, including more heart attacks.

Stem cells are one possible treatment that’s currently being investigated. Unfortunately, loose stem cells don’t stick around for long, because the immune system recognizes that they’re foreign and wipes them out.

So for the new study, the Rice researchers came up with a new way to protect the cells while they did their job. They encased mesenchymal stem cells (MSCs) in alginate hydrogel capsules, a biocompatible material made of brown algae.

“Many of the cells die after transplantation,” says Ravi Ghanta, co-lead author of the study. “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.”

Capsules loaded with stem cells help repair heart damage in mice
Co-lead author Samira Aghlara-Fotovat, with a vial of the stem cell capsules

Jeff Fitlow/Rice University

About 30,000 MSCs were loaded into each 1.5-mm (0.06-in) alginate capsule, and then implanted in mice, near their damaged hearts. After four weeks, the hearts of the mice that had received these “shielded” stem cells had healed as much as 2.5 times more effectively than those of mice that received non-shielded stem cells.

“The immune system doesn’t recognize our hydrogels as foreign, and doesn’t initiate a reaction against the hydrogel,” says Omid Veiseh, co-lead author of the study. “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.”

Of course, the research is still in the early days, and there’s plenty of work left to do before it may make the jump to humans. But the team says that it’s promising, because these kinds of MSCs and hydrogels are already available and in use in patients for other treatments.

The research was published in the journal Biomaterials Science.

Source: Rice University

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