Lipofuscin aggregates in retinal pigment epithelium (Lipofuscin)

Lipofuscin aggregates in the retinal pigment epithelium (RPE) are heterogeneous, autofluorescent deposits composed of lipids, proteins, and bis-retinoid byproducts of the visual cycle (PMID: 22613757). These aggregates accumulate within the lysosomal compartment of RPE cells over time, primarily due to the incomplete digestion of phagocytosed photoreceptor outer segments (NIH, National Eye Institute). The most prominent component, A2E (N-retinylidene-N-retinylethanolamine), is known to be phototoxic and can induce oxidative stress, lysosomal dysfunction, and complement activation (PubMed: 12507450). In pathological conditions like Stargardt disease and Age-related Macular Degeneration (AMD), the accelerated accumulation of lipofuscin leads to RPE atrophy and subsequent loss of photoreceptors, resulting in severe central vision impairment. Current therapeutic approaches aim to mitigate this accumulation by inhibiting the visual cycle to reduce the production of all-trans-retinal (e.g., Emixustat) or by developing agents that facilitate the removal of existing deposits (e.g., Soraprazan) (ClinicalTrials.gov).

Other names

Age pigmentRPE lipofuscinLipofuscin granulesA2E-containing aggregatesRetinal lipofuscinBis-retinoid aggregates

Visual cycle modulation to reduce bis-retinoid formation; RBP4 antagonism to limit retinol uptake; Deuteration of vitamin A to slow dimerization; Lysosomal clearance enhancement