Discovery of retinal elastin and its possible role in age-related macular degeneration

Age-related macular degeneration (AMD) etiology is unknown, but its association to atherosclerotic vascular disease (ASVD) has been observed. Since elastin plays an important role in the atherosclerotic process, to understand ASVD and AMD's relationship we examined retinal elastin existence, elastin amount and vessel properties among normal subjects, mild AMD patients, moderate-to severe AMD patients, and ASVD patients (n = 20). One eye per donor was assigned to enzyme-linked immunosorbent assay for quantifying the retinal elastin amount. The rest were assigned to mechanical test for examining the retinal vessel properties. Additionally, two normal human and two porcine eyes were acquired in immunohistochemistry for locating the retinal elastin. We found that elastin presented in the human and porcine retinal vessels at the basement membranes. 3.73 ± 0.55% of the normal retinal tissues were elastin. Elastin decrease, tissue-weight increase, and vessel hardening and in elasticity (p<0.05) were observed in the retina of patients with ASVD and only moderate-to-severe (i.e., not mild) AMD. Most moderate-to-severe AMD patients also happened to have ASVD. The results suggest that ASVD is unlikely the cause of AMD, but it is perhaps a factor that aggravates the condition through mechanism associated with retinal vessel abnormality.