PURPOSE: The retina contains two distinct populations of monocyte-derived cells: perivascular macrophages, and microglia. The present study was undertaken to evaluate the presence and function in mouse and human retinas of a subtype of resident perivascular macrophages with scavenger function, different from microglia, in physiological conditions and during retinopathy. METHODS: Perivascular macrophages were characterized by means of confocal microscopy, electron microscopy, and flow cytometry analyses. Two murine models of blood-retinal barrier breakdown and photoreceptor degeneration were used to analyze the role of these macrophages during retinopathy. RESULTS: The macrophages analyzed constituted a small population of resident perivascular cells different from microglia, since they were Iba-1 negative. Although these cells expressed F4/80 and CD11b antigens in common with microglia, they also expressed BM8 and MOMA-2 epitopes, which are macrophagic markers not expressed by microglia. Perivascular macrophages emitted autofluorescence due to cytoplasmic inclusions containing protein-bound oxidized lipids. They constitutively expressed the scavenger receptor class A and moved along blood vessels, providing an additional coating to thinner areas of the basement membrane. Moreover, they accumulated blood-borne horseradish peroxidase and acetylated low-density lipoprotein in healthy retinas. In addition, during blood-retinal barrier breakdown and photoreceptor degeneration, these cells migrated to the lesion site. CONCLUSIONS: All these morphologic and functional features are consistent with those described for brain Mato cells. Thus, this study showed the presence of autofluorescent perivascular macrophages, different from microglia, with a scavenger function that may contribute to the maintenance of the blood-retinal barrier in healthy conditions and that are also involved in retinopathy.
PURPOSE: The retina contains two distinct populations of monocyte-derived cells: perivascular macrophages, and microglia. The present study was undertaken to evaluate the presence and function in mouse and human retinas of a subtype of resident perivascular macrophages with scavenger function, different from microglia, in physiological conditions and during retinopathy. METHODS: Perivascular macrophages were characterized by means of confocal microscopy, electron microscopy, and flow cytometry analyses. Two murine models of blood-retinal barrier breakdown and photoreceptor degeneration were used to analyze the role of these macrophages during retinopathy. RESULTS: The macrophages analyzed constituted a small population of resident perivascular cells different from microglia, since they were Iba-1 negative. Although these cells expressed F4/80 and CD11b antigens in common with microglia, they also expressed BM8 and MOMA-2 epitopes, which are macrophagic markers not expressed by microglia. Perivascular macrophages emitted autofluorescence due to cytoplasmic inclusions containing protein-bound oxidized lipids. They constitutively expressed the scavenger receptor class A and moved along blood vessels, providing an additional coating to thinner areas of the basement membrane. Moreover, they accumulated blood-borne horseradish peroxidase and acetylated low-density lipoprotein in healthy retinas. In addition, during blood-retinal barrier breakdown and photoreceptor degeneration, these cells migrated to the lesion site. CONCLUSIONS: All these morphologic and functional features are consistent with those described for brain Mato cells. Thus, this study showed the presence of autofluorescent perivascular macrophages, different from microglia, with a scavenger function that may contribute to the maintenance of the blood-retinal barrier in healthy conditions and that are also involved in retinopathy.
Authors: Tanya Tolmachova; Silene T Wavre-Shapton; Alun R Barnard; Robert E MacLaren; Clare E Futter; Miguel C Seabra Journal: Invest Ophthalmol Vis Sci Date: 2010-05-05 Impact factor: 4.799
Authors: Simone Iwabe; Valerie L Dufour; José M Guzmán; Dolores M Holle; Julie A Cohen; William A Beltran; Gustavo D Aguirre Journal: Vet Ophthalmol Date: 2019-11-20 Impact factor: 1.644
Authors: Jeremy Carlos Burns; Bunny Cotleur; Dirk M Walther; Bekim Bajrami; Stephen J Rubino; Ru Wei; Nathalie Franchimont; Susan L Cotman; Richard M Ransohoff; Michael Mingueneau Journal: Elife Date: 2020-06-24 Impact factor: 8.140