[Molecular and genetic aspects of age-related macular degeneration and glaucoma]

[New findings on pathogenetic mechanisms in the development of age-related macular degeneration]

Age-related macular degeneration (AMD) is a complex multifactorial disease that occurs due to disfunction and degeneration of retinal pigment epithelium (RPE) and choriocapillaris, as well as death of photoreceptors. The exact pathogenetic mechanism remains uncertain. The aging process is the main and the clearest risk factor of AMD. In the development of this condition, a special role belongs to the secretory phenotype of aging spreading from one cell to another and mediated by the secretion and release of growth factors, cytokines, chemokines, proteases, and other molecules. Another major contributor is oxidative stress caused by violations in the recirculation of vitamin A in the vision cycle and accompanied by accumulation of lipofuscin, which mediates the formation of iron-based oxidants that are toxic for mitochondria. Furthermore, prolonged oxidative stress and constant light exposure induce the development of inflammation in the retina. Accumulation of metabolic products and cellular defects with age can induce an inflammatory reaction that amplifies the damage. The inflammatory processes including innate immune response, activation of microglia and parainflammation that occur locally in the vascular membrane, pigment epithelium and neuroretina are very significant contributors to the age-related changes, their progression, and the development of advanced stages of AMD. Various growth factors play a special role in the development of choroidal neovascularization (CNV). Vascular endothelial growth factor A (VEGF-A) has traditionally been considered the main factor of neoangiogenesis and, consequently, the main therapeutic target, but in recent years various studies have determined the role of other factors - VEGF-B, C, D, PGF, Gal-1, angiopoietins. This article describes the main underlying mechanisms in the development of choroidal neovascularization including retinal aging, impaired metabolic activity, mitochondrial dysfunction, inflammatory reactions and genetic variations, as well as the role of various growth factors.

[Antiangiogenic therapy for types I and II macular neovascularization in age-related macular degeneration]

The neovascular form of age-related macular degeneration (AMD) is characterized by growth of newly formed vessels, accumulation of fluid and, in most cases, presence of retinal pigment epithelium detachment. Depending on its localization in relation to retinal pigment epithelium (RPE), macular neovascularization (MNV) can be considered type 1 when it is located under the RPE, and type 2 when it is invading the RPE and the neurosensory part of the retina.

PURPOSE

To conduct a retrospective analysis of the use of anti-VEGF therapy in AMD patients with types I and II of MNV.

MATERIAL AND METHODS

The study enrolled 89 AMD patients (89 eyes) with active MNV who have been under observation for 3 years. In the course of treatment all patients underwent standard ophthalmological examination that included visometry, biomicroscopy and ophthalmoscopy with mydriasis, as well as optical coherence tomography.

RESULTS

Anti-VEGF therapy was found to stabilize best corrected visual acuity (BCVA) in both types of MNV (I and II). Comparison of the intraretinal and subretinal fluids (IRF and SRF) revealed that initially neuroepithelium detachment is more frequent (approximately in 90% of eyes) than IRF (30-40%). Antiangiogenic therapy is associated with better resorption of SRF, by the third year of the follow-up the neuroepithelium detachment is visualized in 60% of patients, while IRF remains and is observed in 40% of cases.

CONCLUSION

Antiangiogenic therapy has shown good functional and morphological effectiveness in both first and second types of MNV.