Abstract
Purpose :
Bestrophinopathies in humans and canine Best (cBest) disease both result from mutations of the BEST1 gene, and share certain features including presentation of retinal lesions. Hyperspectral autofluorescence (AF) imaging in humans ex vivo reveals characteristic signatures in normal eyes and those with age-related macular degeneration (AMD). Similar analysis of cBest fluorophore spectra and distribution in comparison could elucidate understanding of the physiology of both species.
Methods :
Two cBest and two normal canine specimens yielded four tissue cross sections that were captured using 20X field hyperspectral AF imaging (Fig 1a). Excitation wavelengths of 436 480, and 505 nm were used with emissions collected from 420 nm to 720 nm, and the resulting multi-excitation hyperspectral data was unmixed using a non-negative matrix factorization into fluorophore emission spectra and spatial distributions.
Results :
Two of the RPE fluorophore spectral profiles recovered in both normal dogs and cBest (Fig. 1b, spectra C2 and C5) matched those previously described in normal human eyes as S1 (or S1B) and S2 (Ben Ami et al., PMID 27226929). In some samples, only S1B was recovered. These fluorophores localized to both RPE and cBest lesions (Figs. 1c, 1d), instead of just within the RPE as in humans. There was another spectra that corresponded to both weak non-RPE autofluorescence and background noise (C1).
Conclusions :
The presence of human RPE spectra in canine retina, in both normal and cBest samples, offers insight into the physiology of both species, and may apply to human Best disease. The physical distribution in cBest to both RPE and vitelliform lesions warrants further inquiry.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.