Tissue repairing macrophage phenotype is induced by direct interaction with platelets

Abstract

INTRODUCTION: Tissue repair process requires of specialized cells as macrophages. These cells must be stimulated properly to induce tissue repairing macrophage to finally heal tissue. Platelets contain many factors that could be involved in macrophage polarization toward repair profile. In this regard, we tested the hypothesis that macrophage are polarized toward a tissue repair profile following platelet interaction by 24 h. METHODS: Human monocyte-derived macrophages were co-incubated in vitro with platelets. Direct interaction between platelets and macrophages was observed by scanning electron microscopy (SEM) and macrophages were characterized by flow cytometry and ELISA for surface markers and cytokine production, respectively. RESULTS: We observed that non- polarized macrophages interact directly with platelets. This interaction increases CD206 expression and IL-10 production, both characteristics of tissue repairing macrophage. Also, an increase on MHC-II expression and decrease proinflammatory associated markers on macrophages was found. Finally, we shown that proinflammatory macrophages reduce inflammatory markers expression when were stimulated with platelets. CONCLUSION: Macrophages polarization toward repairing phenotype profile occurs after interaction with platelets. Macrophage phenotype is characterized by increases CD206 expression, IL-10 production and diminished inflammatory markers. This observation could occur in vivo in the process healing wound tissue. In addition, it could justify the clinic use of platelet rich plasma on process as inflammation or aged tissue regeneration, where macrophages are involved.