| 19608545 |
Mendes-Jorge L, Ramos D, Luppo M, Llombart C, Alexandre-Pires G, Nacher V, Melgarejo V, Correia M, Navarro M, Carretero A, Tafuro S, Rodriguez-Baeza A, Esperanca-Pina JA, Bosch F, Ruberte J: Scavenger function of resident autofluorescent perivascular macrophages and their contribution to the maintenance of the blood-retinal barrier. Invest Ophthalmol Vis Sci. 2009 Dec;50(12):5997-6005. Epub 2009 Jul 15.
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. |
1(0,0,0,1) |