Abstract
Purpose:
Monocytes and macrophages were implicated in the pathogenesis of age-related macular degeneration (AMD). We aimed to evaluate if M1 and M2 polarized macrophages from AMD patients can modulate the course of laser-induced choroidal neovascularization (CNV) in rodents.
Methods:
Monocytes were isolated from peripheral blood of neovascular AMD (NVAMD) patients (n=12), cultured and matured to an M0 macrophage phenotype. Macrophages were then polarized to either M1 or M2 phenotypes using LPS and IFN-g for M1, and IL-13 and IL-4 for M2, respectively. Generation of polarized macrophages was validated by QPCR for CCL22, CCL17, TNF-α and IL-12. Fluorescently- labeled polarized macrophages and M0 macrophages or PBS were injected into the vitreous of rat eyes 7 days following the formation of laser-induced CNV. Presence of CNV was verified with fluorescein angiogram (FA). Masked observers graded CNV size based on isolectin staining of retinal pigment epithelium (RPE)-choroid flat mounts. Macrophage survival and migration pattern were assessed in retinal and RPE flat mounts.
Results:
QPCR validated macrophage polarization to the M1 and M2 phenotypes. Intravitreal delivery of polarized human macrophages did not cause inflammation according to clinical examination and histology. Injected cells survived more than 7 days in rat eyes and were detected throughout the retinal layers and the vicinity of CNV lesions. Masked assessment of isolectin staining of RPE-choroid flat mounts demonstrated increased CNV size 7 days following injection of M1 (1.3-fold, Mann-Whitney P=0.0001), and M2 (1.4-fold, P=0.012) macrophages, but not following M0 macrophage injection (1.05-fold, P=0.98).
Conclusions:
Intravitreal delivery of polarized macrophages from NVAMD patients is associated with a pro-angiogenic effect in the rat model of laser-induced CNV. This data supports the putative pathogenic role of macrophages in NVAMD and suggests that macrophages may potentially serve as therapeutic target for the disease.
Keywords: 412 age-related macular degeneration •
453 choroid: neovascularization •
557 inflammation