Stem cell capsules repair heart damage in rats

US researchers have developed a new way to heal damaged heart tissue by implanting capsules containing stem cells near to the heart.  

Heart tissue can die when deprived of oxygen during a heart attack. The body can repair some of the damage with scar tissue, but this does not function in the same way as heart muscle and can lead to complications including further heart attacks. 

'With further development, this combination of biomaterials and stem cells could be useful in delivering reparative therapy to heart attack patients,' said study co-lead author Dr Ravi Ghanta from Baylor School of Medicine in Texas.

Stem cells can become any cell in the body. They also produce healing molecules that help tissue regenerate so are a promising treatment option for a variety of conditions. But when stem cells are transplanted into the body, the immune system recognises them as foreign and many of them die. This prompted researchers in Houston Texas to investigate ways to keep them alive for longer.

In this study, the team encased about 30,000 stem cells in a 'hydrogel' – a biologically compatible substance made from brown algae. The stem cells used were mesenchymal stem cells (MSCs), a type of stem cell produced in the bone marrow that had previously been shown to repair tissue after a heart attack. 

Several of the 1.5mm capsules were implanted into rats that had experienced a heart attack. After 28 days, animals treated with capsules of shielded stem cells had 2.5 times more heart healing than rats treated with unshielded stem cells that had been injected directly into the heart.

Study co-lead author Dr Omid Veiseh from Rice University in Texas explained, 'The immune system doesn't recognise our hydrogels as foreign, and doesn't initiate a reaction against the hydrogel. 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.'

More research is needed to see if this approach could be used in humans. But the authors are hopeful that it might be used to treat people in the future.

The study was published in the journal Biomaterials.