Regenerative therapy for the heart

Cardiovascular diseases are the number one cause of mortality in developed countries. A European study explored the feasibility of improving the vascularisation of infarcted myocardium through the transplantation of differentiated cells obtained from stem cells.

Human embryonic stem cells (hESCs) constitute an unlimited source for production of desired cell types including cardiomyocytes, through controlled differentiation. This renders them an invaluable tool for regenerative medicine applications.

Direct injection of hESC-derived cardiomyocytes to the infarcted myocardium demonstrated low functional recovery of the myocardium. This was due to inefficient incorporation of the injected cells but evidence also indicated that the transplanted cells were capable of generating new tissue.

For better retention and viability of the cardiomyocytes, the EU-funded HEARTREGENERATION project proposed to incorporate the cells into an injectable bioactive gel. Prior work in nude mice had shown that combining endothelial and smooth muscle cells led to new vessel formation. In the HEARTREGENERATION study, researchers evaluated the potential of transplanting hESC-derived cardiomyocytes and vascular cells in a gel into a myocardial infarction animal model.

Parameters such as neovascularisation and myocardium functional recovery were evaluated. A synthetic matrix metalloproteinase-responsive hydrogel was generated that facilitated endothelial cell attachment and the formation of a vascular-like network. Using this support material to inject endothelial and smooth muscle cells to the infarcted heart led to an improvement of its contractile capacity.

To support the performance of the transplanted cells, scientists have explored the use of vascular endothelial growth factor in the context of a 3D matrix. Furthermore, they labelled cells with a nanoparticle formulation to track their fate non-invasively using magnetic resonance imaging.

Taken together, the HEARTREGENERATION project provided experimental evidence that cell transplantation in a matrix constitutes a valid approach for cardiac repair. Although the proposed strategy needs to be clinically validated, it offers a promising alternative for restoring vascularisation in the infarcted heart.

related link: http://cordis.europa.eu/result/brief/rcn/12432_en.html