Cerium oxide nanoparticles protect cardiac progenitor cells from oxidative stress.

Cardiac progenitor cells (CPCs) are a promising autologous source of cells for cardiac regenerative medicine. However, CPC culture in vitro requires the presence of microenvironmental conditions (a complex array of bioactive substance concentration, mechanostructural factors, and physicochemical factors) closely mimicking the natural cell surrounding in vivo, including the capability to uphold reactive oxygen species (ROS) within physiological levels in vitro. Cerium oxide nanoparticles (nanoceria) are redox-active and could represent a potent tool to control the oxidative stress in isolated CPCs. Here, we report that 24 h exposure to 5, 10, and 50 µg/mL of nanoceria did not affect cell growth and function in cardiac progenitor cells, while being able to protect CPCs from H(2)O(2)-induced cytotoxicity for at least 7 days, indicating that nanoceria in an effective antioxidant. Therefore, these findings confirm the great potential of nanoceria for controlling ROS-induced cell damage.

Human cardiac progenitor cell grafts as unrestricted source of supernumerary cardiac cells in healthy murine hearts.

Human heart harbors a population of resident progenitor cells that can be isolated by stem cell antigen-1 antibody and expanded in culture. These cells can differentiate into cardiomyocytes in vitro and contribute to cardiac regeneration in vivo. However, when directly injected as single cell suspension, less than 1%-5% survive and differentiate. Among the major causes of this failure are the distressing protocols used to culture in vitro and implant progenitor cells into damaged hearts. Human cardiac progenitors obtained from the auricles of patients were cultured as scaffoldless engineered tissues fabricated using temperature-responsive surfaces. In the engineered tissue, progenitor cells established proper three-dimensional intercellular relationships and were embedded in self-produced extracellular matrix preserving their phenotype and multipotency in the absence of significant apoptosis. After engineered tissues were leant on visceral pericardium, a number of cells migrated into the murine myocardium and in the vascular walls, where they integrated in the respective textures. The study demonstrates the suitability of such an approach to deliver stem cells to the myocardium. Interestingly, the successful delivery of cells in murine healthy hearts suggests that myocardium displays a continued cell cupidity that is strictly regulated by the limited release of progenitor cells by the adopted source. When an unregulated cell source is added to the system, cells are delivered to the myocardium. The exploitation of this novel concept may pave the way to the setup of new protocols in cardiac cell therapy.