Speaker
Description
Introduction
The atrioventricular block constitutes a common congenital disease among pediatric patients. Nowadays the treatment requires repetitive operations for the placement and replacement of technical pacemakers influencing the life quality of young children. In our project, we developed a tissue engineered solution with the aim to avoid the technical pacemakers and therefore the repetitive operations.
Methods
The preparation of the constructs included the fibrin gel embedding of 3 cell types, smooth muscle cells, endothelial and iPSCs-cardiomyocytes constituting the Biopacer1. In particular, the moulding of the Biopacer into a homogeneous tubular matrix made of lyophilised fibrin and silk fibroin was also studied. The lyophilised shield aims to protect the construct from degradation during the future implantation process. The Biopacer was cultivated for various time periods and a diameter of either 0.5 mm or 1 mm to assess the potential functionality of the construct. Cyclic stress was applied in order to increase the extracellular matrix protein formation induced mainly by fibroblasts to strengthen the inner core of the construct. For the evaluation of the constructs, there were glucose and lactate measurements performed. The constructs were also microscopically examined for the determination of the beating frequency of the iPSC-cardiomyocytes. Moreover, the Biopacer was tested for the expression of markers owning to the 3 cell type components.
Results
The glucose and lactate analysis showed that the 0.5 mm diameter Biopacer had a greater lactate production than the 1 mm construct at the end of the cultivation period, while the end glucose levels remained the same. The expression of smooth muscle actin (αSMA) indicating the effect of smooth muscle cells and the CD-31 the effect of endothelial cells respectively, showed that the remodelling in the 1 mm Biopacer construct is functioning. At the same time, the expression of the sarcomeric α-actinin (SAA) indicating the maturity of the iPSCs- cardiomyocytes reflected the maturity of the cells in both diameter constructs and was higher in the 1 mm Biopacer as attributed to the iPSCs-CM number. The beating frequency of the iPSCs-CMs was calculated higher in the fibers containing only iPSCs-CMs while the respective ones of the 0.5 mm and 1 mm were wide declined.
Conclusions
The cell composition of the constructs and the diameter strongly affect the functionalisation of the Biopacer in terms of the lactate production levels and beating frequency. The expression of the iPSCs-CM markers gives us sight to the implementation of the method principles to proceed with the optimisation of the protective shield.
1 Keijdener, H. et al., Journal of Biomedical Materials Research Part B: Applied Biomaterials, 108.4, 1198-1212 (2020).
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