The etiology and pathogenesis of age-related macular degeneration (AMD) are unclear and difficult fot treatment. Some genetic research evidences in recent years have shown that the relationship between lipid metabolism-related gene polymorphism and AMD is statistically significant; it has also been found that blood lipid levels are related to AMD, and lipid-lowering drugs may have the effect of delaying the development of AMD in clinically. Abnormal lipid metabolism may play an important role in the occurrence and development of AMD. Clarifying the role of lipid metabolism in the occurrence and development of diseases will help reveal the pathogenesis of diseases and promote early diagnosis, monitoring and prevention of diseases, and provide an entry point for treatment.
Objective To investigate the correlation between the vitreomacular adhesion (VMA) and exudative age-related macular degeneration (AMD). Methods A literature research was performed in PubMed, EMbase, Cochrane Library, CNKI and Wanfang database from January 2000 to December 2016. Case-control studies on the relationship between VMA or posterior vitreous detachment and exudative AMD were included in this analysis. Literature screening and data extraction were performed according to inclusion and exclusion criteria. The qualities of the literatures were evaluated according to the Newcastle-Ottawa Scale (NOS). Seven literatures were selected into meta-analysis. The NOS score was 9 points in 1 article, 8 scores in 4 articles, 7 points in 2 articles. A total of 947 eyes with exudative AMD, 638 eyes with dry AMD, and 618 eyes with controls were included. The correlation between exudative AMD and VMA were analyzed using the software Review manager 5.3. Results The prevalence of VMA in exudative AMD eyes was higher than that in controls [odds ratio (OR)=2.14, 95% confidence interval (CI)=1.19 - 3.84, P=0.010] and dry AMD eyes (OR=2.24, 95%CI=1.24 - 4.03, P=0.007). There was no difference in PVD prevalence among exudative AMD eyes, dry AMD eyes (OR=0.44, 95%CI=0.16 - 1.20, P=0.110) and controls (OR=0.70, 95%CI=0.41 - 1.18, P=0.180). Conclusion There is correlation between VMA and exudative AMD.
Photoreceptor cells are special retinal neurons with photo-transformation ability. Loss of photoreceptors in age-related macular degeneration (AMD) is secondary to RPE loss, leakage of serum components from the neovascularization and scar formation, which is one of the main mechanisms of irreversible visual impairment in patients with AMD. Many studies have shown that inflammatory environment is involved in the process of photoreceptor cell death. Aging, photooxidation injury and other factors affects the retinal microenvironment through different levels of mechanisms such as retinal pigment epithelial cells, retinal glial cells, hematogenous macrophages and inflammatory factors, which results in photoreceptor injuries and participates in the progression of AMD by drusen formation and neovascularization. This study reviews the research status and progress of inflammation and photoreceptor cell death, and provides new ideas for exploring the blinding mechanism and treatment strategies of AMD.
The hallmark lesions of age-related macular degeneration (AMD) are drusen and basal linear deposit which are lipid substances deposited in Bruch membrane or the compartment on the Bruch membrane. There is a prevailing hypothesis that lipid and its oxidized derivant deposited in retina may have important roles in the pathogenesis of AMD. Lipid oxidation products are toxic, may affect the adjacent cells, induce inflammation, and trigger neovascularization.7-ketocholestoral (7KCh), a naturally occurring oxidized form of cholesterol, had been found to be toxic to retinal cells and able to induce chronic inflammation, which may play a critical role in the development of AMD. However the precise mechanism remains to be elucidated. Thus we will make a brief review of 7KCh and its association with AMD.
Macular pigment (MP) is composed of lutein, zeaxanthin, and meso-zeaxanthin, which accumulate mainly at the macula. MP has antioxidant function and can filtering blue wave. Measurement of MP is about its optical density, that is, macular pigment optical density (MPOD). This review summarizes the function and clinical use of MP and MPOD. Researches has show that MPOD is related to some ocular disease such as age-related macular degeneration, macular telangiectasia type 2, diabetic retinopathy, Stargardt disease et al. MPOD can be used in the judgment of clinical diagnosis, treatment effect. The specific mechanism of MP metabolism in the retina and in the pathogenesis of the disease, genotype specific nutritional therapy of xanthophyll, the establishment of a database combined with artificial intelligence and the rapid and convenient MP determination are all issues of great contention that need to be resolved.