Myeloid Lineage Cell during Healing: Friend or Foe

Background: Inflammation, following skin injury, initiates aseries of autocrine and paracrine signals as well as a fine-tunedcellular interplay. Myeloid cells are one of the leading playersin this orchestrated phenomenon.Materials and Methods: Using in vitro and in vivo models ofinjuries, we highlight the contribution of myeloid cells as wellas their fate during skin healing. We evaluate this role in differentmodels of healings, including deficient and excessive healing.Results: While myeloid cells show an essential role in normalskin healing, disturbed myeloid cells contribute to the deficienthealing of aged animals. Conversely, the augmented and sustainedfunction of myeloid cells contributes to excessive healing,leading to scar formation.Conclusions: These works introduce a paradigm in which myeloidcells are recognized as the significant player in granulationtissue formation and skin healing.