Age-related macular degeneration: an overview / Degeneração macular relacionada à idade: um panorama geral

ABSTRACT Age-related macular degeneration is the most important cause of irreversible vision loss in the elderly and has been considered a severe public health problem. Current treatments have only been successful in delaying the loss of central vision. Due to increased life expectancy, governments and researchers have been challenged to seek more efficient and successful treatments for age-related macular degeneration. Considering its relevance for public health and the need of further research, this article aims to address age-related macular degeneration objectively, tackling on the current knowledge about its pathophysiology, potential molecular biomarkers, main prevention procedures and treatments, as well as introducing possible molecules that may be a therapeutic target in this disease.

RESUMO Degeneração macular relacionada à idade é a causa mais importante de perda irreversível da visão em idosos, e é considerada um sério problema de saúde pública. Os tratamentos atuais são bem-sucedidos apenas ao postergar a perda da visão central. Devido à maior expectativa de vida, os governos e pesquisadores têm dificuldade de encontrar tratamentos mais eficientes e exitosos para degeneração macular relacionada à idade. Considerando sua relevância para saúde pública e a necessidade de mais pesquisas, este artigo procura abordar a degeneração macular relacionada à idade de forma objetiva, abordando os conhecimentos atuais sobre sua fisiopatologia, potenciais biomarcadores moleculares, principais procedimentos de prevenção e tratamentos, e apresentar possíveis moléculas que podem ser alvo terapêutico nessa doença.

Expression of TNF-α and IL-6 cytokines in the choroid and sclera of hypercholesterolemic rabbits / Expressão das citocinas TNF-α and IL-6 na coroide e esclera de coelhos hipercolesterolêmicos

Purpose: This study aimed to evaluate the expression of the inflammatory cytokines TNF-α and IL-6 in the sclera and choroid of hypercholesterolemic rabbits. Method: Twenty-one New Zealand male albino rabbits were divided into two groups: NG and HG. The NG group was fed a standard rabbit diet and the HG group was fed a cholesterol-enriched diet (1%). The serum total cholesterol, triglyceride, HDL cholesterol, and fasting blood glucose levels were determined at the beginning of the experiment and on the day of euthanasia. Euthanasia of animals in the NG and HG groups was performed at the end of the 4th and 8th week, respectively. The eyes were analyzed immunohistochemically using TNF-α and IL-6 antibodies. Results: At the time of euthanasia, the HG group showed a significant increase in total cholesterol and triglyceride when compared with the NG group (p<0.001). When compared with the NG group, there was a significant increase in the expression of TNF-α (p<0.001) and IL-6 (p=0.002) in the choroid and sclera of animals in the HG group. Conclusion: This study demonstrates that the hypercholesterolemic diet induces expression of TNF-α and IL-6 in the choroid and sclera of rabbits. .

Objetivo: Avaliar a expressão das citocinas inflamatórias TNF-α e IL-6 na esclera e coroide de coelhos hipercolesterolêmicos. Método: Coelhos New Zealand foram organizados em dois grupos: GN recebeu ração padrão para coelhos; GH recebeu dieta rica em colesterol a 1%. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 4ª semana para o GN e 8ª semana para o GH foi realizada a eutanásia dos animais. Os olhos foram submetidos à análise imuno-histoquímica com os anticorpos TNF-α e IL-6. Resultados: O GH manifestou significativo aumento do colesterol total e triglicerídeos em relação ao GN (p<0,001). Houve significativo aumento da expressão da TNF-α (p<0,001) e da IL-6 (p=0,002) na coroide e esclera dos animais do GH em relação ao GN. Conclusão: Este estudo demonstra que a dieta hipercolesterolêmica induz ao aumento da expressão das citocinas TNF-α e IL-6 na coroide e esclera de coelhos. .

The role of oxidative stress and antioxidants in the pathogenesis of age-related macular degeneration

OBJECTIVE: To investigate the role of oxidant/antioxidant status and protein oxidation in the development of age-related macular degeneration. METHOD: The activities of serum superoxide dismutase and glutathione peroxidase and the levels of serum malondialdehyde, advanced oxidation protein products, glutathione and vitamin C were measured in 25 patients with age-related macular degeneration and 25 control subjects without age-related macular degeneration. RESULT: The malondialdehyde and advanced oxidation protein product levels in the serum were significantly higher in the age-related macular degeneration patient group than in the control group (p<0.05). The superoxide dismutase activity in the serum was significantly lower in the age-related macular degeneration patient group than in the control group (p<0.05). The levels of vitamin C and glutathione and the activity of glutathione peroxidase in the serum were unchanged between groups (p>0.05). CONCLUSION: The results of the present study suggest that decreased effectiveness of the antioxidant defense system and increased oxidative stress may play a role in the pathogenesis of age-related macular degeneration.