A study focused on macrophages modulation induced by the Polymeric Electrospun Matrices (EL-Ms) for application in tissue regeneration: in vitro proof of concept.

Abstract A successful regenerative process has to consider the role of immune system after surgical implantation of a polymer-based matrix due to the reaction of monocytes and macrophages cells after contact with biomaterial. Pro-inflammatory (TNF-alfa, IL-6 and IL-8) and anti-inflammatory (IL-10) cytokines released by macrophages cells are fundamental in acute inflammatory response (2-3 days) to destroy pathogens and help scaffold during regenerative process supporting the up-regulation of ECM and endothelial progenitor cells. Aim of this work was to evaluate the in vitro acute response induced by pre-optimized polymeric electrospun matrices (EL-Ms), after 3 days contact with macrophages (M0) and EL-Ms ability to modulate M1 and/or M2 macrophages polarization. Biological characterization included MTT, LDH and Live/Dead assays, immunological characterization by ELISA for cytokine-expression levels determination. Morphological characterization was carried out by Confocal Laser Scanning Microscopy and Scanning Electron Microscopy. The results showed an initial pro-inflammatory response (after 24h) characterized by release of TNF-alfa, IL-6 and IL-8 cytokines. A preferential anti-inflammatory response was highlighted after 72h, demonstrated by higher release of IL-10 and elongation of macrophages in contact with EL-Ms, that is typical of M2 cell polarization. EL-Ms could be used as eligible support to enhance tissue regeneration promoting an anti-inflammatory response.