Black, White, and Gray: Macrophages in Skin Repair and Disease

Abstract

Purpose of Review Macrophages alter their responses during the temporal stages of wound healing. During the inflammatory phase macrophages perform phagocytosis. During neovascularization macrophages activate angiogenesis. In the proliferation phase of wound healing, macrophages deposit extracellular matrix and during wound resolution macrophages phagocytize excessive cellular components. This review addresses how these changing phenotypes affect skin repair and disease. Recent Findings Macrophages can determine the outcome of repair and can shift the normal wound healing response into fibrosis or chronic wounds. Emerging single cell technologies for the first time provide us with tools to uncover macrophage origin, heterogeneity and function. Summary Macrophages may exist as one population where all cells alter their phenotype in response to signals from the microenvironment. Alternatively, macrophages may exist as distinct subsets that can control wound outcomes. A clarified understanding will strengthen our knowledge of skin biology and aid in the development of wound healing therapies.

Wound-Healing Markers Revealed by Proximity Extension Assay in Tears of Patients following Glaucoma Surgery

“…The increased amount of PARP-1, osteoclast-associated immunoglobulin-like receptor, SOD2, and GLO1 may indicate the presence of additional stress factors in the group where complications are present. The signal transducing adapter molecule (STAM)-binding protein initiates cell growth and cell proliferation, while the eukaryotic initiation factor EIF4EBP1 has a role in the regulation of translation; both are needed for the increased cell proliferation that is required for wound closure [60]. The increased amounts of molecules whose decrease was associated with the delayed wound healing (SOD2, GLO1, PARP-1) and of those molecules that have a role in proliferation (STAM-binding protein, EIF4EBP1) might reflect premature wound healing, leading to the ineffective trabeculectomy that is characteristic in the group with complications.…”

Snail Slime Extracted by a Cruelty Free Method Preserves Viability and Controls Inflammation Occurrence: A Focus on Fibroblasts

“…Tissue macrophages are the most abundant resident immune cell type of the skin, participating in homeostasis and healing processes. Under homeostatic conditions, their primary role is to scavenge cellular and macromolecular degradation intermediates while, when stimulated by inflammatory or pathological stimuli along with microorganisms in the dermis, they become activated [ 19 ]. A major pathway in host defense is the activation of the transmembrane protein toll-like receptor 4 (TLR4) in innate immune cells.…”

Evaluation of Small Molecular Polypeptides from the Mantle of Pinctada Martensii on Promoting Skin Wound Healing in Mice

“…When inflammation subsides, neutrophils, and associated molecular factors are reduced, leading to changes in the microenvironment of the tissues [31]. Thus, the inflammatory macrophage phenotype was transformed into an anti-inflammatory cell type that directly promotes fibrosis during granulation tissue formation [32]. This decrease in inflammation is essential to prevent the development of the chronic healing process, which eventually leads to the formation of fatty scars [13].…”