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 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.
Objective To compare the characteristics of the ocular fundus of exudative age-related macular degeneration (AMD) with polypoidal choroidal vasculopathy (PCV). Methods The photographs of ocular fundus of 123 patients (137 eyes) with exudative AMD and 42 patients (48 eyes) with PCV diagnosed by fundus photography, fundus fluorescein angiography (FFA), and indocyanine green angiography (ICGA) were retrospectively analyzed. Results In 137 eyes with exudative AMD, 16 eyes (11.7%) had classic neovascularization (CNV), 121 (88.3%) had occult CNV. In the eyes with occult CNV, 42 eyes (34.7%) had hot spots, 74 eyes (61.2%) showed plaque hyperfluorescences and 2 eyes (1.7%) had hot spots with PCV in ICGA. In 48 eyes with PCV, 7 eyes (14.6%) had subretinal reddish-orange lesions, 2 eyes (4.2%) of the polypoidal dilations with branching vascular network were detected with FFA, 36 eyes (75.0%) demonstrated polypoidal dilations with branching vascular network, and 12 eyes (25.0%) showed scattered polypoidal dilations without identifiable continuous branching vascular network, 16 eyes (33.3%) had the polypoidal dilations resembling a cluster of grapes, and 32 eyes (66.3%) showed the polypoidal dilations as several solitary round aneurismal dilations. The polypoidal dilations showed either a washout of the dye from the polyp with staining of its walls or staining of the dye in the late phase of ICGA. Conclusions The different features of exudative AMD and PCV in the ICGA, and the PCV with subretinal reddish-orange lesions are useful in the differentiate diagnosis of the both diseases. (Chin J Ocul Fundus Dis，2004，20：307-309)
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）
Purpose To evaluate shortterm visual acuity effects of a single photodynamic therapy(PDT) treatment with Visudyne (CIBA Vision Corp, Duluth, Ga) for choroidal neovascularization (CNV) in age-related macular degeneration (AMD). Methods Definitely diagnostic AMD patients with classic CNV were treated with PDT (5 cases, 7 eyes). The data of visual acuity testing, ophthalmic examination, color photographs, optic coherence tomography, fluorescein angiograms and indocyanine green angiogram before photodynamic therapy and 1 week ,1 month after it were used to evaluate the effects of a single treatment of PDT with Visudyne. Results The visual acuity of all the treated eyes at the follow-up examination at 1 month after PDT were not reduced. Distinct reduction of fluorescein leakage from CNV was noted in all patients by 1 week after PDT. Fluorescein leakage from a portion of the CNV reappeared by 1 month after treatment in 2 eyes. Conclusion PDT with Visudyne achieved short-term cessation of fluorescein leakage from CNV without loss of vision or growth of classic CNV in some patwo ients with AMD. (Chin J Ocul Fundus Dis,2000,16:213-216)
Age-related macular degeneration (AMD) is an age-related degenerative disease with complex pathogenesis, whose initial lesion is accompanied with immune inflammatory response. Amyloid beta (Aβ), a small-molecule protein generated by the hydrolysis of amyloid precursor protein, as the main component, is involved in the formation of drusen, which serves as the early characteristic of AMD. In the local inflammatory response of AMD, Aβ is an important pathological deposit, promoting the proliferation and differentiation of macrophages as well as changing their morphology to accelerate the progression of AMD. In addition, Aβ can also regulate immune molecules and the complement system by activating inflammatory pathways, thus mediating chronic retinal inflammation and promoting the course of AMD. However, since AMD is not caused by inflammation alone, only the immunosuppression may not be effective in inhibiting the course of AMD, and thus the future development is to rebalance the disordered immune system in AMD patients eyes.
ObjectiveTo observe and classify the characteristics of optical coherence tomography (OCT) for several common diseases which could lead to submacular choroidal neovascularization (CNV), and to provide the warrant to make the differential diagnosis and treatment of CNV.MethodsThe data of OCT of 165 patients (187 eyes) with CNV due to AMD, CEC, high myopia and ICNV diagnosed by fundus photography and fundus fluorescein angiography (FFA) were retrospectively analyzed, and the images of OCT were classified considering the results of FFA, and the characteristics of different types of the images were sumerized.ResultsWell-defined fusiform thickening of retinal pigment epithelial (RPE) and choriocapillary layer in CNV with well-defined border (60 eyes), dispersed backscattering increase in poorly-defined CNV (101 eyes), optic darkspace beneath RPE layer in serous detachment of RPE layer (19 eyes), quickly decreased high backscattering region under RPE layer in hemorrhagic detachment of RPE layer (11 eyes), slight to moderate backscattering region between RPE layer in fibrovascular detachment of RPE layer (10 eyes), and detachment of neurepithelial layer from RPE layer with the optic darkspace between the layers in detachment of neurepithelial layer (45 eyes) were observed.ConclusionsThe images of OCT for the common diseases which could lead to submacular choroidal neovascularization may be divided into 6 types. Analyzing the characteristics of images of OCT is helpful in differential diagnosis and treatment of CNV. (Chin J Ocul Fundus Dis, 2005,21:69-73)
Objective To study the significance of detection the short-term fluctuation (SF) of macular light threshold detected by Octopus-123 automatic perimeter in suspected early age-related macular dege-neration (AMD). Methods SF of macular light sensitivity, Amsler chart and central visual acuity were examined in 51 patients(66 eyes) with suspected early AMD group and in 32 patients (40 eyes) in the control group. Results SF were significantly different in suspected early AMD group and control group. SF was more sensitive than the examination of central visual acuity and Amsler chart. SF was related to the quantity, location and quality of drusen. Conclusion Visual function of some suspected early AMD patients with drusen may be damaged, though the central visual acuity appears normal. (Chin J Ocul Fundus Dis, 2002, 18: 119-120)
Objective To evaluate the visual function before and after photodynamic therapy(PDT) in patients with subfoveal choroidal neovascularization ( CNV) caused by age-related macular degeneration (AMD). Methods Twenty-five consecutive patients (34 eyes) treated with PDT (verteporfin) for subfoveal CNV in age-related macular degeneration diagnosed by fluorescein angiography (FFA), indocyanine green angiography (ICGA) and optical coherence tomography (OCT). Visual function including best corrected visual acuity, contrast sensitivity frequency, binocular function, confusion, stereo-vision, color vision, metamorphopsis and central scotoma were examed before photodynamic therapy and 1 week, 1 month, 3 month after photodynamic therapy. The follow-up time varied from 3 months to 2 years (mean 7.6 months). Results The changes of visual function at the 3rd month after photodynamic therapy revealed improving in 13 eyes (38.24%), without any change in 17 eyes (50.00%), and decreasing in 6 eyes (17.65%). Visual acuity with logMRA improved after photodynamic therapy, but without statistic difference. All spatial contrast sensitivity improved. Contrast sensitivity for spatial frequencies 5 cycles per degree (cpd) was better after photodynamic therapy with significant difference (P=0.045).Binocular function, fusion function, stereo function and color vision were slightly improved without statistic difference. Conclusion Damage of visual function in macular degeneration is many-sided. The treatment of PDT for exudative AMD can improve part visual function. (Chin J Ocul Fundus Dis，2004，20：289-291)