Plasma-activated hydrogels for in vitro fibrotic cardiac tissue modelling

Ischemic heart disease is caused by cardiomyocyte death under hypoxic conditions, followed by the formation of a dysfunctional fibrotic scar. Reactive oxygen species (ROS) play an important role in this process. Physical atmospheric pressure plasmas (APP), generate unique mixtures of ROS and started to be considered for medical therapy. Due to the many potentials of this blooming new field ahead, there is a need to exploit the main concepts derived from plasma research in chemistry and biology as a mechanistic link between the ROS production from APP and their medical benefit (1). Indeed, different types and doses of in vivo-like ROS can be generated by APP treatment of physiological solutions, and their effects on different cell types have been studied, including ROS-induced cell apoptosis (2). On the other hand, the exploitation of APP treatment to model in vitro diseased tissues has not been reported up to now. The aim of this work was to develop an in vitro cardiac fibrotic tissue model for preclinical studies of drugs. An APP was used to generate ROS at a proper amount to induce oxidative stresses into human adult cardiac fibroblasts (AHCFs) without affecting their viability. Cells were exposed to plasma-activated medium for 24 h and their viability was evaluated after 1, 3 and 7 days. AHCF activation into myofibroblasts was also analyzed versus control conditions. Then, ROS-loaded hydrogels were prepared with proper concentration and crosslinking degree to match the stiffness of healthy and fibrotic cardiac tissues. ROS stability into the starting polymer solutions and their release kinetics from freshly-prepared hydrogels were studied. ROS-loaded hydrogels were used for AHCF culture. In the future, an in vitro model of the fibrotic cardiac tissue will be prepared using the selected ROS-loaded hydrogel and its structural and functional properties will be analyzed.