Systemic Administration Of An Anti-amyloid Beta Monoclonal Antibody Interferes With The Ocular Pathology Of A Mouse Model Of Age-related Macular Degeneration (AMD) / Retinal Dysfunction

Abstract

Purpose: : Neovascular AMD has effective treatments, but no effective therapies are available for the dry/atrophic form of the disease. Data now support involvement of the alternative complement pathway in AMD development, particularly defects in complement factors H, (CFH) and B, (CFB). A transgenic CFH-gene deficient mouse model, (cfh-/-) shows hallmarks of early AMD - formation of ocular: autofluorescent basement membrane deposits with further retinal deposition of both activated complement C3 and amyloid beta. Cfh-/- mice were treated systemically in both prophylactic and therapeutic regimes with a GSK anti-amyloid beta monoclonal antibody (αAbeta mAb) to determine the effect on the cfh-/- retinal phenotype.

Methods: : Cfh-/- mice were treated at 3 months, (prophylaxis), and at 6 months, (therapy), weekly for 12 weeks. After treatment, efficacy end points, for both regimes were: quantification of retinal autofluorescent, basement membrane deposits by confocal scanning laser ophthalmoscope (cSLO) imaging, IHC analysis and quantification of retinal deposition of amyloid beta & activated complement C3, demonstration of elevated levels of total amyloid-ß protein / mAb complexes in sera.

Results: : Prophylactic treatment with a GSKαAbeta mAb demonstrated a dose dependent: Reduction in basement membrane deposits, reduction in amyloid beta and activated complement deposition, elevation in serum amyloid beta. A similar reduction in these endpoints could be seen after therapeutic treatment.

Conclusions: : Both prophylactic and therapeutic regimes with a GSK αAbeta mAb demonstrate that ocular phenotypes of the cfh-/- mouse can be reduced or partially reversed. Serum amyloid beta levels after systemic administration show accumulation of amyloid beta in the periphery and suggest removal of retinal amyloid beta deposition by a peripheral sink mechanism consistent with the proposed mechanism of this agent. The data support this therapeutic approach in humans.

Keywords: age-related macular degeneration • retina • drusen