Quantitative Fundus Autofluorescence in Rhesus Macaques in Aging and Age-Related Drusen

Area of Science:

• Ophthalmology
• Nonhuman Primate Models
• Retinal Imaging

Background:

• Age-related macular degeneration (AMD) is a leading cause of vision loss.
• Retinal pigment epithelial (RPE) lipofuscin accumulation is a hallmark of aging and AMD.
• Nonhuman primates (NHPs) offer a valuable model for studying human ocular diseases.

Purpose of the Study:

• To utilize quantitative fundus autofluorescence (qAF) imaging in rhesus macaques.
• To noninvasively assess RPE lipofuscin in NHPs as a model for aging and AMD.
• To compare qAF findings in NHPs with known human AMD characteristics.

Main Methods:

• Employed qAF imaging in 26 rhesus macaques (aged 4-27 years).
• Used confocal scanning laser ophthalmoscopy with 488 nm excitation.
• Measured qAF levels (qAF8) and correlated with age, sex, and drusen presence/volume via multivariable regression analysis.

Main Results:

• Mean qAF levels increased with age (P < 0.001) and were higher in females (P = 0.047).
• Eyes with soft drusen showed reduced mean qAF (P = 0.003) but focal hyperautofluorescence over drusen lesions (P < 0.001).
• Larger drusen lesions were associated with increased hyperautofluorescence (R2 = 0.391, P < 0.001).

Conclusions:

• qAF in rhesus macaques reflects age and sex effects, and altered lipofuscin in drusen, mirroring some aspects of human AMD.
• Hyperautofluorescence over drusen in NHPs contrasts with human findings, suggesting species-specific differences in RPE lipofuscin.
• This NHP model provides insights into drusen biogenesis and AMD pathogenesis, highlighting both similarities and divergences.