Dr Hiroki Hata is a cardiovascular surgeon from Osaka, Japan. Since 2007, Hata has been working at the Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO) and the Cardiac, Thoracic, Transplantation and Vascular Surgery department at Hannover Medical School, Hannover, Germany. His main focus was to connect the innovative technologies of cardiac regenerative therapy established independently at both Osaka University and Hannover Medical School. At this EACTS meeting, he will be presenting the recent achievement of this venture: the gener- ation of a novel myocardial patch.

   A persistent problem in generating an in vitro functional myocardial patch is maintaining contractions and cell viability in a thicker construct. Thus far in Hannover, we have successfully created contracting constructs with a defined directionality by seeding neonatal rat cardiomyocytes (CM) on decellularised porcine small intestinal submucosa (SIS) In Osaka, we have been investigating the transfer of CM cell sheets, as a regenerative therapy option.

   Here, Hata and his team report efforts in generating a thicker contracting construct by combining CM cell sheets with CM-seeded SIS (sSIS) To do so, porcine SIS is decellularised, opened along the longitudinal axis, and fixed in a metal frame. The mucosa side is then seeded with neonatal rat CM. CM sheets are prepared using temperature-responsive dishes that allow the removal of the CM as a monolayer with a change in temperature. Three days after CM seeding, once CM sheet or three-layered CM sheets are stacked onto sSlS. Construct contraction is observed for an additional ten days followed by histological analysis. Stacked CM sheets contracted spontaneously and synchronously with sSlS after adherence.

   A majority of analysed constructs show a defined contraction direction, parallel to the longitudinal axis. The thickness of sSlS with and without three-layered sheets was approximately 800μm and 500μm, respectively. By combining layered CM sheets with sSlS, a BD myocardial patch with contraction in a defined direction can be successfully generated. Moreover, our novel myocardial patch is a good foundation for our final goal; a vascularised and contracting 3D myocardial graft. Such an innovative graft may be used surgically to support diseased myocardial tissue upon implantation in the future.