Age-related macular degeneration is one of the major causes of blindness in the elderly. As an important pathway of cell metabolism, autophagy maintains intracellular homeostasis through the degradation and recycle of damaged organelles and macromolecules. Understanding its mechanism may promote discoveries to delay aging process, reduce the incidence of age-related diseases. In mammals, silent information regulator protein 6 (SIRT6) plays its deacetylase and ribonucleotransferase activity in multiple signaling pathways, including inhibition of cellular senescence, tumorigenesis, metabolic diseases, regulating cellular lifespan. It has a significant impact on the structure and function of tissues and organs. SIRT6 regulates intracellular autophagy mainly through the insulin-like growth factor-protein kinase B-mammalian target of rapamycin, reducing the accumulation of toxic metabolites and cellular senescence. The function of SIRT6 in age-related macular degeneration need to be combined with the genetic background, pathogenesis, clinical manifestations and other aspects of the disease, and it is expected to be further studied in subsequent studies.
The therapeutic effect of anti-vascular endothelial growth factor (VEGF) for neovascular age-related macular degeneration (nAMD) was determined by a number of factors. Comprehensive thorough analysis of clinical features, imaging results and treatment response can predict the potential efficacy and possible vision recovery for the patient, and also can optimize the treatment regime to make a personalized therapy plan. Precise medicine with data from genomics, proteomics and metabolomics study will provide more objective and accurate biology basis for individual precise treatment. The future research should focus on comprehensive assessment of factors affecting the efficacy of anti-VEGF therapy, to achieve individualized precise diagnosis and treatment, to improve the therapeutic outcome of nAMD.
The prevalence of diabetes mellitus in adults of China has reached 12.8%. Diabetic retinopathy (DR) accounts for approximately 1/4-1/3 of the diabetic population. Several millions of people are estimated suffering the advanced stage of DR, including severe non-proliferative DR (NPDR), proliferative DR (PDR) and diabetic macular edema (DME), which seriously threat to the patients’ vision. On the basis of systematic prevention and control of diabetes and its complications, prevention of the moderate and high-risk NPDR from progressing to the advanced stage is the final efforts to avoid diabetic blindness. The implementation of the DR severity scale is helpful to assess the severity, risk factors for its progression, treatment efficacy and prognosis. In the eyes with vision-threatening DR, early application of biotherapy of anti-vascular endothelial growth factor can improve DR with regression of retinal neovascularization, but whether it is possible to induce capillary re-canalization in the non-perfusion area needs more investigation. Laser photocoagulation remains the mainstay treatment for non-center-involved DME and PDR.
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.
ObjectiveTo investigate the course of the idiopathic macular hole (IMH) clinically diagnosed as at stage Ⅰ-Ⅳ by optical coherence tomography (OCT), and analyze the relationship between the posterior vitreous detachment (PVD) and the course of IMH. MethodsHadn′t undergone any operation, periodical OCT were performed on 72 eyes of 58 patients with IMH at stage Ⅰ-Ⅳ confirmed by Gass standard and the features of OCT images.ResultsThe longest follow-up period was 43 months (average 13.4 months), and the examine times of OCT on each eye were between twice to 10 times (average 4.7 times). During the followup period, 23 eyes were in stage I in which 9 (39.1%) developed to stage II and 2 had recovered normal curve of fovea after PVD; 19 were in stage II in which 13 (68.4%) developed to Ⅲ-Ⅳ and 1 had closed hole after PVD; 11 were in stage III in which 5 (45.5%) developed to stage IV and 1 had partly closed hole 12 months later. The images of OCT showed that the process of macular hole was consistent with the course that vitreous depart from retina from the circumference of fovea till entire posterior detachment.Fifteen affected eyes in this series of patients had undcrygong surgical treatment due to serious progression of IMH in follow-up period. ConclusionsThere is a close relationship between the formation and development of macular hole and the occurrence of PVD. OCT can show the progress of the macular hole directly and offer an important technique in diagnosis, classification and surgical treatment of IMH. (Chin J Ocul Fundus Dis, 2005,21:79-82)
Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
Flicker and photopic eletroretinogram(ERG)were recorded for 45 eyes of dry type of age-related macular degeneration(AMD)and 24 eyes of wet type of AMD respectively,the amplitud and phase of fundamental response compomeng(30Hz)by discrete Fourier tranform(DFT)were analysed.The abnormality ratios of phases and amplitudes in fundamental responses,amplitudes of photopic white or red b-waves were 48.89%,8.89%,10.11% and 8.89% respectively.The visual acuities of 24 eyes were 1.0 or better,the abnormality ratios of phases were up to 37.50%.These suggest that the change of phases is a sensitive method for detecting the early abnormality of visual function in AMD.The abnormality ratios of phases and amplitudes in fundamental responses were 62.5% and 45.84% in wet type of AMD.The differences between dry type and wet type in amplitudes of fundamental responses and photopic b-waves were statistically significant(P＜0.01).This shows that the change of amplitudes is associated with the degree of pathological change of AMD. （Chin J Ocul Fundus Dis,1996,12: 41-43）