Exosomes in the treatment of age-related ophthalmic diseases: an updated review

Exosomes are nanoscale extracellular vesicles of endosomal origin that mediate intercellular communication by transferring bioactive cargo, including proteins, lipids, messenger RNAs, microRNAs, and other regulatory molecules. Through this process, they can modulate the biological functions of recipient cells. Age-related ophthalmic diseases, including age-related macular degeneration (AMD), dry eye disease (DED), and age-related cataract (ARC), are degenerative ocular conditions whose incidence increases with age and are associated with chronic inflammation, oxidative stress, dysregulated angiogenesis, tissue fibrosis, epithelial injury, and apoptosis. Diabetic retinopathy (DR), although not classically defined as an age-related ophthalmic disease, is also briefly discussed in this review as an age-associated metabolic retinal comorbidity. Existing clinical treatments have several limitations, including the need for repeated administration, variable therapeutic responses, and potential adverse effects. Because of their biocompatibility, low immunogenicity, modifiable cargo and potential for local delivery, exosomes are being investigated as therapeutic agents and drug delivery vehicles in ophthalmology. This review summarizes the biological characteristics of exosomes and their potential relevance to ophthalmic applications, reviews recent evidence on their roles and mechanisms in major age-related ophthalmic diseases, and discusses the current limitations and future directions of exosome-based therapeutic strategies.