Choroidal Neovascularization Is Inhibited in Splenic-Denervated or Splenectomized Mice with a Concomitant Decrease in Intraocular Macrophage

Abstract

PurposeTo determine the involvement of sympathetic activity in choroidal neovascularization (CNV) using laser-induced CNV in a mouse model.MethodsWe investigated changes in the proportions of intraocular lymphocytes, granulocytes, and three macrophage subtypes (Ly6Chi, Ly6Cint, and Ly6Clo) after laser injury in mice using flow cytometry, and evaluated CNV lesion size in mice lacking inflammatory cells. Further, we evaluated the lesion size in mice administered the β3 receptor antagonist, splenic-denervated and splenectomized mice. We also assessed changes in the proportions of intraocular macrophages and peripheral blood monocytes in splenic-denervated and splenectomized mice. Lastly, lesion size was compared between splenic-denervated mice with or without adoptive transfer of macrophages following laser injury. After Ly5.1 mice spleen-derived Ly6Chi cells were transferred into Ly5.2 mice, the proportions of intraocular Ly5.1+Ly6Chi cells were compared.ResultsIn WT mice, the proportion of CD4+ T cells recruited into the eye increased progressively from day 3 to day 7 after laser injury, whereas, intraocular CD8+ T cells did not change significantly. Proportions of B220+ cells, granulocytes, and two subtypes of intraocular macrophages (Ly6Chi and Ly6Clo) peaked at day 3 following laser injury. In contrast, Ly6Cint/loCD64+ subtype showed a significantly higher percentage at day 7 after laser injury. There were no differences in lesion size between CD4–/–or Rag2–/–mice and controls, whereas lesion size was significantly reduced in CCR2−/− mice and clodronate liposome-treated mice. CNV lesion area was significantly reduced in mice with β3 blocker treatment, splenic-denervated and splenectomized mice compared with controls. Intraocular Ly6Chi macrophages were also reduced by splenic denervation or splenectomy. Adoptive transfer of spleen-derived Ly6Chi cells increased the lesion size in splenic-denervated mice. Compared with controls, intraocular donor-derived Ly6Chi cells recruited into the eye were reduced in splenic-denervated and splenectomized mice.ConclusionsAlthough lymphocytes had little effect on CNV formation, Ly6Chi macrophages/monocytes exacerbated CNV in mice. Sympathetic activity might contribute to CNV via the recruitment of macrophages to the eye.

Aqueous humour proteins and treatment outcomes of anti-VEGF therapy in neovascular age-related macular degeneration

“…may be in line with a recent hypothesis that a subpopulation of macrophages, referred to as alternatively activated macrophages, may be involved in nAMD [58]. Inflammation occurring in eyes with nAMD is mediated by several types of immune cell, among which myeloid cells (macrophages/monocytes) are considered to be of the utmost importance.…”

Inhibition of the alternative complement pathway accelerates repair processes in the murine model of choroidal neovascularization

“…It is unlikely that the systemic levels were derived from the eye, but rather, it is more likely due to independent systemic complement activation in response to the release of damaging components from the eye into the circulation. A contribution of the splenic immune response to CNV lesions has been shown by us (Coughlin et al, 2016) and others (Tan et al, 2016). However, irrespective of the source of the anaphylatoxins, it can be argued that elevated serum anaphylatoxin levels, as are found in late-stage neovascular AMD patients (Smailhodzic et al, 2012) and in mouse CNV (our data here), are associated with higher anaphylatoxin levels in the eye.…”

Asian age-related macular degeneration: from basic science research perspective

“…We speculate that macrophages' polarization from protective to destructive phenotypes is due to continuous stimulation by molecular "garbage" such as oxidized lipid products whose generation-disposal balance becomes impaired with aging. In contrast to the roles of macrophages, roles of lymphocytes and granulocytes in CNV are less clear [52]. Of note a recent study identified mast cell degranulation in the choroid of all stages of AMD [53].…”