Stem cells have been shown to be promising as a treatment for heart disease. But that’s only one part of solving the problem. Transplanted cells die after implantation due to the hostile environment they find themselves in, including the patient’s own immune system, which fights against the stem cells, even when they’re trying to help.

Researchers from Rice University and Baylor College of Medicine may have come up with an answer. They’ve developed capsules which encase mesenchymal stem cells (MSCs) in a hydrogel material made out of brown algae. This shielded approach protects the stem cells from the host, while allowing them to perform the function of delivering reparative proteins that are secreted by the cells.

“Alginate is a naturally occurring polymer found in seaweed which can form a gel in presence of divalent cations,” Omid Veiseh, assistant professor in the Department of Bioengineering at Rice University, told Digital Trends. “The material can be fabricated into spheres quite easily, using reactions which are friendly to the cells we load into the capsules. Alginate hydrogel formulations are quite prevalent in various medical products, and are also used widely in the food industry. One such example is vegan caviar. The unique aspect of our approach is that our [capsules] are formulated using a version of alginate polymer we developed that is immunomodulatory. These polymers have been chemically modified such that the body no longer recognizes the material as foreign.”

The stem cell capsules have not yet been demonstrated in humans. However, in a study carried out using rodents, the stem cells were implanted next to wounded hearts using minimally invasive techniques. Within a month, the heart healing was 2.5x greater in animals that had been given the special shielded stem cells than it was in animals which had not been given these stem cells.

“The next step is to further develop the delivery strategy for how to get the shielded stem cell into position on top of the heart using minimally invasive catheters. and further validation in chronic heart failure models,” Ravi Ghanta, associate professor of surgery at Baylor College of Medicine, told Digital Trends. “With further development and testing this approach could be utilized in a variety of cell therapies for the heart.”

A paper describing the work was recently published in the journal Biomaterials Science.