Age-related macular degeneration (AMD) is still an incurable blinding eye disease because of complex pathogenic mechanisms and unusual diseased regions.With the use of chemical biology tools,great progress has been ac...Age-related macular degeneration (AMD) is still an incurable blinding eye disease because of complex pathogenic mechanisms and unusual diseased regions.With the use of chemical biology tools,great progress has been achieved in improving the understanding of AMD pathogenesis.The severity of AMD is,at least in part,linked to the non-degradable lipofuscin bis-retinoids in retinal pigment epithelial (RPE).This material is thought to result from the lifelong accumulation of lysosomal residual bodies containing the end products derived from the daily phagocytosis of rod outer segments by RPE cells.Here,we present previously recognized bis-retinoids with focus on structures and biosynthetic pathways.In addition to a brief discussion on the mutual conversion relationships of bis-retinoids,future perspectives and the medical relevance of such studies on these lipofuscin constituents are also highlighted.展开更多
AIM To investigate the effect of two ways of lipofuscin production(lipid peroxidation and glycation) on lipofuscin fluorescence characteristics and phototoxicity and to compare them with the properties of natural lipo...AIM To investigate the effect of two ways of lipofuscin production(lipid peroxidation and glycation) on lipofuscin fluorescence characteristics and phototoxicity and to compare them with the properties of natural lipofuscin.METHODS Model lipofuscins were prepared on the basis of bovine photoreceptor outer segments(POS) with bisretinoid A2 E addition. One set of samples was prepared from POS modified by lipid peroxidation,while another set from POS modified by glycation with fructose. Fluorescent properties and kinetics of photoinduced superoxide generation of model lipofuscins and human retinal pigment epithelium(RPE) lipofuscin were compared. The fluorescence spectra of samples were measured at 365 nm excitation wavelength and 380-650 emission wavelength. RESULTS The fluorescence spectra of model lipofuscins are almost the same as the spectrum of natural lipofuscin. Visible light irradiation of both model lipofuscins and natural lipofuscin isolated from RPE cells leads to decrease of a fluorescence maximum at 550 nm and to appearance of a distinct,new maximum at 445-460 nm. The rate of photogeneration of reactive oxygen forms by both model lipofuscins was almost the same and approximately two times less than that of RPE lipofuscin granules.CONCLUSION These data suggest that fluorescent characteristics and phototoxicity of lipofuscin granules depend only to an insignificant degree on the oxidative modification of POS proteins and lipids,and generally are defined by the bisretinoid fluorophores contained in them.展开更多
Gene and drug therapies are being developed to al eviate vision loss in patients with Stargardt’s disease and age-related macular degeneration （AMD）. To evaluate the therapeutic effects of these treatments, organic...Gene and drug therapies are being developed to al eviate vision loss in patients with Stargardt’s disease and age-related macular degeneration （AMD）. To evaluate the therapeutic effects of these treatments, organic sol-vents are routinely used to extract and quantify bisretinoid lipofuscin constituents, such as N-retinylidene-N-retinyl-ethanolamine （A2E） and all-trans-retinal dimer （ATR-dimer）. By high-performance liquid chromatography （HPLC）, we found that A2E and ATR-dimer were both altered by tetrahydrofuran （THF） and chloroform, but were stable in dimethyl sulfoxide （DMSO） or methanol （MeOH）. In addition, cyclohexane and ethanol （EtOH） did not alter ATR-dimer, whereas an alteration of A2E occurred in EtOH. On the basis of these findings, we designed processes II-IV, generated by modifications of process I, a routine method to measure bisretinoid compounds in vivo. Extra amounts of either ATR-dimer or A2E in mouse eyecups were released by processes II-IV versus process I. Efforts to clarify the effects of organic solvents on lipofuscin pigments are important because such studies can guide the handling of these fluoro-phores in related experiments.展开更多
Lipofuscin-like pigments (LFPs) are highly oxidized cross-linked aggregates of oxidized protein and lipids which are formed under oxidative state conditions by free radicals produced. The present study aimed to evalua...Lipofuscin-like pigments (LFPs) are highly oxidized cross-linked aggregates of oxidized protein and lipids which are formed under oxidative state conditions by free radicals produced. The present study aimed to evaluate the probable ameliorative effects of some of the Mn-salens namely EUKs 8, 134, 15, 115, 122 and 132 (compounds 1-6) and vitamin C against carbon tetrachloride (CCl4)-induced acute damage on rats’ livers and brains. Exposure to CCl4 is believed to induce oxidative stress and cause tissue damage due to the formation of trichloromethyl (·CCl3) and peroxy trichloromethyl (·OOCCl3) radicals. In this study, 54 rats were randomly divided into 9 groups of six each: normal group received only vehicle (olive oil;2 ml/kg b.w.) for 6 consecutive days;CCl4- intoxicated group received the vehicle and CCl4 (50% solution of CCl4 in olive oil, 2 ml/kg b.w.) on the first and second days and the vehicle on the third to sixth days;test rats received Mn-salens or vitamin C (20 mg/kg b.w.) and CCl4 (2 ml/kg b.w.) on the first and second days and Mn-salens or vitamin C (20 mg/kg b.w.) on the third to sixth days. Mn-salens administration ameliorated the effects of CCl4 by decreasing the levels of ROS, lipid and protein oxidations and LFPs formation on liver and brain as well as cholesterol and triglycerides, aminotransferases and alkaline phosphatase contents in sera of rats whereas increased the activities of catalase, superoxide dismutase,glutathione reductase, glutathione peroxidase and reduced glutathione in liver and brain tissues. Histopathological studies confirmed the toxic effects of CCl4 and ameliorative action of Mn-salens on tissues. These results suggest that the evaluated EUKs were able to attenuate LFPs accumulation and morphological changes caused by CCl4 in rats and thus, confirming the ameliorative role of Mn-salens against CCl4-induced oxidative damage and age-related diseases.展开更多
Purpose:.To compare melanin-related near-infrared fundus autofluorescence (NIA; excitation 787 nm, emission> 800 nm) with lipofuscin-related fundus autofluorescence (FAF; excitation 488 nm, emission > 500 nm) in...Purpose:.To compare melanin-related near-infrared fundus autofluorescence (NIA; excitation 787 nm, emission> 800 nm) with lipofuscin-related fundus autofluorescence (FAF; excitation 488 nm, emission > 500 nm) in patients with idiopathic choroidal neovascularization (ICNV). Methods: FAF, NIA, fundus fluorescein angiography (FFA) and indocyanine green angiography.(ICGA).were obtained using a confocal scanning laser Ophthalmoscope HRA2 (Heidelberg Retina Angiograph 2).in 18 eyes of 18 patients with ICNV. Results:.Eighteen eyes had classic CNV, and autofluorescence imaging showed hypoautofluorescence at the site of CNV..A well-defined hyperautofluorescent ring was detected surrounding the CNV in all 18 eyes with NIA imaging. In our sample,.the FAF patterns around the CNV were classified as normal (n=1,.5.56%), well-defined hyperautofluorescent ring (n=7,.38.89%), or ill-defined hyperautofluorescent ring (n=10, 55.56%). Conclusion:.The patterns of FAF and NIA indicated different involvement of lipofuscin and melanin in the pathophysiological process of ICNV. Compared to FAF imaging, NIA imaging appears to be a superior noninvasive method for in vivo visualization of retinal pigment epithelium (RPE) abnormalities in ICNV patients.展开更多
目的研究藏麻黄(Ephedra saxatilis Royle ex Florin.)水提取物对秀丽隐杆线虫抗衰老及抗氧化作用。方法将野生型N2线虫分别暴露于藏麻黄水提取物100、300、500μg·mL^(-1)处理组及正常对照组(Normal),通过寿命实验、咽泵频率检测...目的研究藏麻黄(Ephedra saxatilis Royle ex Florin.)水提取物对秀丽隐杆线虫抗衰老及抗氧化作用。方法将野生型N2线虫分别暴露于藏麻黄水提取物100、300、500μg·mL^(-1)处理组及正常对照组(Normal),通过寿命实验、咽泵频率检测、产卵量测定、运动能力评估、脂褐素荧光强度分析、丙二醛(MDA)含量、还原性谷胱甘肽(GSH)及抗氧化酶[超氧化物歧化酶(SOD)和过氧化氢酶(CAT)]活性测定,评价其抗衰老效果。结果与对照组相比,不同浓度的藏麻黄水提取物均能延长线虫寿命(P<0.05),降低脂褐素积累(P<0.01),CAT活性(P<0.01)与GSH含量(P<0.05)增加,并呈现剂量依赖性;MDA水平在高浓度组降低(P<0.01);SOD活性在高浓度组(300、500μg·mL^(-1))降低。此外,藏麻黄水提取物对线虫咽泵频率、产卵量及体长体宽无明显影响(P>0.05)。结论藏麻黄水提取物可能通过激活CAT与GSH抗氧化通路、抑制脂质过氧化(MDA)及降低脂褐素积累,有效延缓线虫衰老进程,但其对SOD的调控机制需进一步研究。展开更多
Background:Cells of the retinal pigment epithelium(RPE)accumulate different kinds of granules(lipofuscin,melanolipofuscin,melanosomes)within their cell bodies,with lipofuscin and melanolipofuscin being autofluorescent...Background:Cells of the retinal pigment epithelium(RPE)accumulate different kinds of granules(lipofuscin,melanolipofuscin,melanosomes)within their cell bodies,with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation.High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration(AMD);however,this has not been confirmed in histology so far.Here,based on our previous dataset of RPE granule characteristics,we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence(AF)intensities.Methods:RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy(HR-SIM)and laser scanning microscopy(LSM).Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules.In addition,total AF intensity per cell and granule density(number of granules per cell area)were determined.For the final analysis,RPE cells with total granule number below 5th or above the 95th percentile,or a total AF intensity±1.5 standard deviations above or below the mean were included,and compared to the average RPE cell at the same location.Data are presented as mean±standard deviation.Results:Within 420 RPE cells examined,42 cells were further analyzed due to extremes regarding total granule numbers.In addition,20 RPE cells had AF 1.5 standard deviations below,28 RPE cells above the mean local AF intensity.Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity.RPE cells with high granule content have nearly twice(1.8 times)as many granules as an average RPE cell.Conclusions:In normal eyes,outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells,suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level.The AF of a cell is related to the composition of intracellular granule types.Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscin´s role in aging and AMD further into perspective.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21202146 and 81271018)the Fundamental Research Funds for the Central Universities,Chinathe Zhejiang Key Laboratory Fund of China(No.2011E10006)
文摘Age-related macular degeneration (AMD) is still an incurable blinding eye disease because of complex pathogenic mechanisms and unusual diseased regions.With the use of chemical biology tools,great progress has been achieved in improving the understanding of AMD pathogenesis.The severity of AMD is,at least in part,linked to the non-degradable lipofuscin bis-retinoids in retinal pigment epithelial (RPE).This material is thought to result from the lifelong accumulation of lysosomal residual bodies containing the end products derived from the daily phagocytosis of rod outer segments by RPE cells.Here,we present previously recognized bis-retinoids with focus on structures and biosynthetic pathways.In addition to a brief discussion on the mutual conversion relationships of bis-retinoids,future perspectives and the medical relevance of such studies on these lipofuscin constituents are also highlighted.
基金The Russian Foundation for Basic Research,No.15-29-03831
文摘AIM To investigate the effect of two ways of lipofuscin production(lipid peroxidation and glycation) on lipofuscin fluorescence characteristics and phototoxicity and to compare them with the properties of natural lipofuscin.METHODS Model lipofuscins were prepared on the basis of bovine photoreceptor outer segments(POS) with bisretinoid A2 E addition. One set of samples was prepared from POS modified by lipid peroxidation,while another set from POS modified by glycation with fructose. Fluorescent properties and kinetics of photoinduced superoxide generation of model lipofuscins and human retinal pigment epithelium(RPE) lipofuscin were compared. The fluorescence spectra of samples were measured at 365 nm excitation wavelength and 380-650 emission wavelength. RESULTS The fluorescence spectra of model lipofuscins are almost the same as the spectrum of natural lipofuscin. Visible light irradiation of both model lipofuscins and natural lipofuscin isolated from RPE cells leads to decrease of a fluorescence maximum at 550 nm and to appearance of a distinct,new maximum at 445-460 nm. The rate of photogeneration of reactive oxygen forms by both model lipofuscins was almost the same and approximately two times less than that of RPE lipofuscin granules.CONCLUSION These data suggest that fluorescent characteristics and phototoxicity of lipofuscin granules depend only to an insignificant degree on the oxidative modification of POS proteins and lipids,and generally are defined by the bisretinoid fluorophores contained in them.
基金Project supported by the National Natural Science Foundation of China(Nos.21202146 and 81271018)the Fundamental Research Funds for the Central Universities+1 种基金the Zhejiang Scientific Research Foundation for the Returned Overseas Chinese Scholars(No.J20120556)the Zhejiang Key Laboratory Fund of China(No.2011E10006)
文摘Gene and drug therapies are being developed to al eviate vision loss in patients with Stargardt’s disease and age-related macular degeneration （AMD）. To evaluate the therapeutic effects of these treatments, organic sol-vents are routinely used to extract and quantify bisretinoid lipofuscin constituents, such as N-retinylidene-N-retinyl-ethanolamine （A2E） and all-trans-retinal dimer （ATR-dimer）. By high-performance liquid chromatography （HPLC）, we found that A2E and ATR-dimer were both altered by tetrahydrofuran （THF） and chloroform, but were stable in dimethyl sulfoxide （DMSO） or methanol （MeOH）. In addition, cyclohexane and ethanol （EtOH） did not alter ATR-dimer, whereas an alteration of A2E occurred in EtOH. On the basis of these findings, we designed processes II-IV, generated by modifications of process I, a routine method to measure bisretinoid compounds in vivo. Extra amounts of either ATR-dimer or A2E in mouse eyecups were released by processes II-IV versus process I. Efforts to clarify the effects of organic solvents on lipofuscin pigments are important because such studies can guide the handling of these fluoro-phores in related experiments.
文摘Lipofuscin-like pigments (LFPs) are highly oxidized cross-linked aggregates of oxidized protein and lipids which are formed under oxidative state conditions by free radicals produced. The present study aimed to evaluate the probable ameliorative effects of some of the Mn-salens namely EUKs 8, 134, 15, 115, 122 and 132 (compounds 1-6) and vitamin C against carbon tetrachloride (CCl4)-induced acute damage on rats’ livers and brains. Exposure to CCl4 is believed to induce oxidative stress and cause tissue damage due to the formation of trichloromethyl (·CCl3) and peroxy trichloromethyl (·OOCCl3) radicals. In this study, 54 rats were randomly divided into 9 groups of six each: normal group received only vehicle (olive oil;2 ml/kg b.w.) for 6 consecutive days;CCl4- intoxicated group received the vehicle and CCl4 (50% solution of CCl4 in olive oil, 2 ml/kg b.w.) on the first and second days and the vehicle on the third to sixth days;test rats received Mn-salens or vitamin C (20 mg/kg b.w.) and CCl4 (2 ml/kg b.w.) on the first and second days and Mn-salens or vitamin C (20 mg/kg b.w.) on the third to sixth days. Mn-salens administration ameliorated the effects of CCl4 by decreasing the levels of ROS, lipid and protein oxidations and LFPs formation on liver and brain as well as cholesterol and triglycerides, aminotransferases and alkaline phosphatase contents in sera of rats whereas increased the activities of catalase, superoxide dismutase,glutathione reductase, glutathione peroxidase and reduced glutathione in liver and brain tissues. Histopathological studies confirmed the toxic effects of CCl4 and ameliorative action of Mn-salens on tissues. These results suggest that the evaluated EUKs were able to attenuate LFPs accumulation and morphological changes caused by CCl4 in rats and thus, confirming the ameliorative role of Mn-salens against CCl4-induced oxidative damage and age-related diseases.
基金supported by a grant from the Science and Technology Support Project of Gansu Province(No.090NKCA093)
文摘Purpose:.To compare melanin-related near-infrared fundus autofluorescence (NIA; excitation 787 nm, emission> 800 nm) with lipofuscin-related fundus autofluorescence (FAF; excitation 488 nm, emission > 500 nm) in patients with idiopathic choroidal neovascularization (ICNV). Methods: FAF, NIA, fundus fluorescein angiography (FFA) and indocyanine green angiography.(ICGA).were obtained using a confocal scanning laser Ophthalmoscope HRA2 (Heidelberg Retina Angiograph 2).in 18 eyes of 18 patients with ICNV. Results:.Eighteen eyes had classic CNV, and autofluorescence imaging showed hypoautofluorescence at the site of CNV..A well-defined hyperautofluorescent ring was detected surrounding the CNV in all 18 eyes with NIA imaging. In our sample,.the FAF patterns around the CNV were classified as normal (n=1,.5.56%), well-defined hyperautofluorescent ring (n=7,.38.89%), or ill-defined hyperautofluorescent ring (n=10, 55.56%). Conclusion:.The patterns of FAF and NIA indicated different involvement of lipofuscin and melanin in the pathophysiological process of ICNV. Compared to FAF imaging, NIA imaging appears to be a superior noninvasive method for in vivo visualization of retinal pigment epithelium (RPE) abnormalities in ICNV patients.
文摘目的研究藏麻黄(Ephedra saxatilis Royle ex Florin.)水提取物对秀丽隐杆线虫抗衰老及抗氧化作用。方法将野生型N2线虫分别暴露于藏麻黄水提取物100、300、500μg·mL^(-1)处理组及正常对照组(Normal),通过寿命实验、咽泵频率检测、产卵量测定、运动能力评估、脂褐素荧光强度分析、丙二醛(MDA)含量、还原性谷胱甘肽(GSH)及抗氧化酶[超氧化物歧化酶(SOD)和过氧化氢酶(CAT)]活性测定,评价其抗衰老效果。结果与对照组相比,不同浓度的藏麻黄水提取物均能延长线虫寿命(P<0.05),降低脂褐素积累(P<0.01),CAT活性(P<0.01)与GSH含量(P<0.05)增加,并呈现剂量依赖性;MDA水平在高浓度组降低(P<0.01);SOD活性在高浓度组(300、500μg·mL^(-1))降低。此外,藏麻黄水提取物对线虫咽泵频率、产卵量及体长体宽无明显影响(P>0.05)。结论藏麻黄水提取物可能通过激活CAT与GSH抗氧化通路、抑制脂质过氧化(MDA)及降低脂褐素积累,有效延缓线虫衰老进程,但其对SOD的调控机制需进一步研究。
文摘Background:Cells of the retinal pigment epithelium(RPE)accumulate different kinds of granules(lipofuscin,melanolipofuscin,melanosomes)within their cell bodies,with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation.High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration(AMD);however,this has not been confirmed in histology so far.Here,based on our previous dataset of RPE granule characteristics,we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence(AF)intensities.Methods:RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy(HR-SIM)and laser scanning microscopy(LSM).Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules.In addition,total AF intensity per cell and granule density(number of granules per cell area)were determined.For the final analysis,RPE cells with total granule number below 5th or above the 95th percentile,or a total AF intensity±1.5 standard deviations above or below the mean were included,and compared to the average RPE cell at the same location.Data are presented as mean±standard deviation.Results:Within 420 RPE cells examined,42 cells were further analyzed due to extremes regarding total granule numbers.In addition,20 RPE cells had AF 1.5 standard deviations below,28 RPE cells above the mean local AF intensity.Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity.RPE cells with high granule content have nearly twice(1.8 times)as many granules as an average RPE cell.Conclusions:In normal eyes,outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells,suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level.The AF of a cell is related to the composition of intracellular granule types.Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscin´s role in aging and AMD further into perspective.
