Giant phagocytes (Gφ) and neutrophil-macrophage hybrids in human carotid atherosclerotic plaques - An activated phenotype.

A small subpopulation of CD66b+ neutrophils with extended lifespan and immensely large size was identified Thirty-three plaques were obtained from 31 patients undergoing endarterectomy. Carotid plaques were analyzed for CD markers by immunohistochemistry and immunofluorescence and quantitatively analyzed by confocal microscopy. Intra-plaque lipids were stained with Oil Red O. Plaque CD66b+ neutrophils co-expressed myeloperoxidase (MPO)+ and neutrophil elastase (NE)+. Also, co-expression of CD66b+/CD68+, CD66b+/CD36+, CD66b+/vascular-endothelial-growth- factor (VEGF)+ and 3-nitrotyrosine (3-NT)+/NE+ was noted. Similarly, macrophages co-expressed CD163+/CD68+, CD163+/VEGF+ and CD163+/3-NT+. Both cell types were predominantly localized in lipid-rich areas and stained for lipids. CD66b+ and CD163+ expressions were highly positively correlated with each other and each with CD68+, and 3-NT+. Morphologically, CD66+ cells were big, had a rounded nucleus, and resembled macrophage-foam cell morphology as well as that of Gφ Thus, we conclude that in some of the plaques CD66b+ cells might represent cells resembling Gφ that developed in prolonged culture conditions. Yet, CD66b+/CD163+ co-expressing cells represent a new neutrophil-macrophage hybrid population of unknown transitioning point, possibly by adopting macrophage markers or contrariwise. Nonetheless, the significance and functions of these cells in plaque biology or other inflammatory/atherosclerotic conditions should be unveiled.

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Copyright © 2023 Lavie, Si-on and Hoffman.

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The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.