ACU 4429 is an inhibitor of retinal pigment epithelium 65 (RPE65; IC50 = 4.4 nM), an enzyme that catalyzes the isomerization of 11-trans retinol to 11-cis retinol in the visual cycle.1 It reduces rod photoreceptor recovery in dark-adapted mice after photobleaching (ED50 = 0.21mg/kg) and reversibly decreases the regeneration of 11-cis retinal oxime in the same model (ED50 = 0.18 mg/kg). ACU 4429 also prevents light-induced photoreceptor cell loss in dark-adapted albino mice. It reduces lipofuscin autofluorescence and decreases the level of retinoid toxin (A2E) in the RPE in an Abca4-/- mouse model of Stargardt disease (ED50 = 0.47 mg/kg).
1.Bavik, C., Henry, S.H., Zhang, Y., et al.Visual cycle modulation as an approach toward preservation of retinal integrityPLoS One10(5)e0124940(2015)