Abstract 221: Tannic Acid Coated Nanoparticles for Cardiac Regeneration

The advance of nanomedicines has recently offered novel approaches to tackle cardiovascular diseases and, in particular, myocardial infarction (MI). However, the constant pumping of the heart and the still poor knowledge of targetable moieties, prevented the application of nanomedicines in the cardiovascular field to rise. Tannic acid, a polyphenol derived from plants, has showed affinity for components of the extracellular matrix, in particular elastin, allowing the retention of protein aggregates in the cardiac tissue. Here, we explored the heart targeting abilities of tannic acid by using it to coat spermine modified-acetalated dextran (AcDXSp) nanoparticles (NPs). Briefly, particles were prepared by single emulsion technique and then coated with tannic acid by complexation of the polyphenol with Fe 3+ ions, resulting in the formation of a capsule around the AcDXSp NPs. The nanoparticles were loaded with two small hydrophobic compounds, CHIR99021 and SB431542, which were both proven to increase the efficiency of direct reprogramming of fibroblasts into cardiomyocytes. The biocompatibility of the nanosystem and cellular uptake were performed on both primary rat cardiomyocytes and fibroblasts. The nanoparticles were taken-up by both the cell types and were safe towards primary cardiomyocytes, while the tannic acid coating showed anti-fibrotic effects on primary fibroblasts. Anti-fibrotic effect was further confirmed by RT-qPCR and the effect of the loaded compounds was assessed by β-catenin and Smad3 immunostainings, which demonstrated the ability of the system to induce direct reprogramming of fibroblasts into cardiomyocytes. In particular, the system stabilized β-catenin and prevented the translocation of Smad3 to the nucleus of myo(fibroblasts). In conclusion this nanosystems exhibited potential to tackle the negative fibrosis process occurring after myocardial infarction by both contrasting it, due to the anti-fibrotic effects showed by the tannic acid coating and by potentially regenerating the cardiac tissue, due to the efficient direct reprogramming of fibroblasts into cardiomyocytes exerted by the loaded drugs.