Towards a functional tissue engineered cardiac muscle

Previous studies showed that engineered cardiac muscle with features resembling those of native cardiac tissues can be designed in vitro. In the present study, laminin coating of the polymer scaffolds was used in conjunction with cultivation in low serum medium, in order to improve tissue properties. Primary ventricular cardiac muscle cells were seeded onto polymer scaffolds, laminin coated or not, and cultured at low or high serum concentration. Positive immunofluorescence staining for the gap junctional protein connexin-43 provided evidence that cells in the engineered tissues were electrically coupled. Low serum increased the amount of myosin heavy chain, while laminin increased the amount of creatine kinase isoform MM. Electrophysiological properties for the laminin-low serum group, such as conduction velocity, approached the levels of neonatal ventricles; the maximum capture rate and maximum amplitude were also significantly improved.