Cardiac cell death is an irreversible consequence of a myocardial infarction, often resulting in a chronically reduced cardiac output and symptoms of CHF. German researchers from Max Planck Institute for Heart and Lung Research in Bad Nauheim have been working with Indian scientists to create a scaffold within which cardiac cells can be safely populated and then used as patches for damaged hearts.
They discovered that silk protein fibroin from Antheraea mylitta, a tasar silkworm found in India, can be an excellent material to support lab grown cardiac cells. So far the team has been working with rat heart cells, and though the research is promising they don’t see a clear path to clinical studies due to the difficulty of gathering patients’ own cardiac cells.
“Whether natural or artificial in origin, all of the tested fibres had serious disadvantages,” says Felix Engel, Research Group Leader at the Max Planck Institute for Heart and Lung Research in Bad Nauheim. “They were either too brittle, were attacked by the immune system or did not enable the heart muscle cells to adhere correctly to the fibres.” However, the scientists have now found a possible solution in Kharagpur, India.
At the university there, coin-sized disks are being produced from the cocoon of the tasar silkworm (Antheraea mylitta). According to Chinmoy Patra, an Indian scientist who now works in Engel’s laboratory, the fibre produced by the tasar silkworm displays several advantages over the other substances tested. “The surface has protein structures that facilitate the adhesion of heart muscle cells. It’s also coarser than other silk fibres.” This is the reason why the muscle cells grow well on it and can form a three-dimensional tissue structure. “The communication between the cells was intact and they beat synchronously over a period of 20 days, just like real heart muscle,” says Engel.
Despite these promising results, clinical application of the fibre is not currently on the agenda. “Unlike in our study, which we carried out using rat cells, the problem of obtaining sufficient human cardiac cells as starting material has not yet been solved,” says Engel. It is thought that the patient’s own stem cells could be used as starting material to avoid triggering an immune reaction. However, exactly how the conversion of the stem cells into cardiac muscle cells works remains a mystery.
Abstract in Biomaterials: Silk protein fibroin from Antheraea mylitta for cardiac tissue engineering