Abstract
Purpose
Subretinal macular fibrosis occurs in up to 50% of neovascular age-related macular degeneration (nAMD) eyes and is a major cause of anti-VEGF resistance in nAMD. Currently, there are no medications to prevent or treat macular fibrosis secondary to nAMD. The aim of this study was to investigate the role of CC-chemokine receptor 2 (CCR2) expressing monocytes in the development of the fibrovascular phenotype of nAMD.
Methods
Subretinal fibrosis was induced in C57BL/6J mice using the two-stage laser-induced protocol previously described by Little et al (2020). The dynamics of the fibrotic lesion and infiltrating macrophages were assessed by immunofluorescence staining of collagen-1, F4/80 and CCR2, respectively at days 0, 1, 3, 6 and 10 post-second laser. Circulating CCR2+ monocytes were depleted using the CCR2 depleting antibody, MC-21, from day 1 to day 5 (acute stage depletion) or from day 5 to day 10 (chronic stage depletion). The level of depletion was confirmed by flow cytometry. Vascular and fibrotic components of the fibrovascular membrane were examined at day 10 post-second laser by immunofluorescence staining of isolectin B4 and collagen-1, respectively.
Results
The fibrotic lesion size reaches its peak 3 days after the second laser. CCR2+F4/80+ macrophages were detected in and around the fibrotic lesion and their number increased from day 3 to 10 post-second laser. Depletion of CCR2+ monocytes at the acute stage of disease did not affect the size of subretinal fibrosis. However, depletion of CCR2+ monocytes at the chronic stage of the disease significantly reduced the vascular and fibrotic components of the fibrovascular membrane.
Conclusions
Our results suggest that CCR2+ monocytes play a critical role in the development of the fibrovascular phenotype of nAMD during the chronic stage of inflammation. The underlying mechanism of CCR2+monocytes in promoting subretinal fibrosis warrants further investigation.
Subretinal macular fibrosis occurs in up to 50% of neovascular age-related macular degeneration (nAMD) eyes and is a major cause of anti-VEGF resistance in nAMD. Currently, there are no medications to prevent or treat macular fibrosis secondary to nAMD. The aim of this study was to investigate the role of CC-chemokine receptor 2 (CCR2) expressing monocytes in the development of the fibrovascular phenotype of nAMD.
Methods
Subretinal fibrosis was induced in C57BL/6J mice using the two-stage laser-induced protocol previously described by Little et al (2020). The dynamics of the fibrotic lesion and infiltrating macrophages were assessed by immunofluorescence staining of collagen-1, F4/80 and CCR2, respectively at days 0, 1, 3, 6 and 10 post-second laser. Circulating CCR2+ monocytes were depleted using the CCR2 depleting antibody, MC-21, from day 1 to day 5 (acute stage depletion) or from day 5 to day 10 (chronic stage depletion). The level of depletion was confirmed by flow cytometry. Vascular and fibrotic components of the fibrovascular membrane were examined at day 10 post-second laser by immunofluorescence staining of isolectin B4 and collagen-1, respectively.
Results
The fibrotic lesion size reaches its peak 3 days after the second laser. CCR2+F4/80+ macrophages were detected in and around the fibrotic lesion and their number increased from day 3 to 10 post-second laser. Depletion of CCR2+ monocytes at the acute stage of disease did not affect the size of subretinal fibrosis. However, depletion of CCR2+ monocytes at the chronic stage of the disease significantly reduced the vascular and fibrotic components of the fibrovascular membrane.
Conclusions
Our results suggest that CCR2+ monocytes play a critical role in the development of the fibrovascular phenotype of nAMD during the chronic stage of inflammation. The underlying mechanism of CCR2+monocytes in promoting subretinal fibrosis warrants further investigation.
| Original language | English |
|---|---|
| Journal | Investigative Opthalmology and Visual Science |
| Volume | 63 |
| Issue number | 7 |
| Publication status | Published - 01 Jun 2022 |
| Event | Association for Research in Vision and Ophthalmology Annual Meeting 2022 - New Orleans, USA, Denver, United States Duration: 01 May 2022 → 04 May 2022 https://www.arvo.org/annual-meeting/ |
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Deciphering the role of macrophages in subretinal fibrosis secondary to neovascular Age Related Macular Degeneration (nAMD)
Szczepan, M. (Author), Xu, H. (Supervisor), Chen, M. (Supervisor) & Fitzgerald, D. (Supervisor), Dec 2023Student thesis: Doctoral Thesis › Doctor of Philosophy