Inner blood-retina barrier involvement in dry age-related macular degeneration (AMD) pathology.
Ontology highlight
ABSTRACT:
SUBMITTER: Hudson N
PROVIDER: S-EPMC7437601 | biostudies-literature | 2020 Sep
REPOSITORIES: biostudies-literature
Publications
Inner blood-retina barrier involvement in dry age-related macular degeneration (AMD) pathology.
Hudson Natalie N Cahill Mark M Campbell Matthew M
Neural regeneration research 20200901 9
Similar Datasets
Project description:Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness worldwide in the elderly population. The pathology of dry AMD consists of macular degeneration of photoreceptors and the RPE, lipofuscin (A2E) accumulation, and drusen formation. Mice have been widely used for generating models that simulate human AMD features for investigating the pathogenesis, treatment and prevention of the disease. Although the mouse has no macula, focal atrophy of photoreceptors and RPE, lipofuscin accumulation, and increased A2E can develop in aged mouse eyes. However, drusen are rarely seen in mice because of their simpler Bruch's membrane and different process of lipofuscin extrusion compared with humans. Thus, analyzing basal deposits at the ultrastructural level and understanding the ultrastructural pathologic differences between various mouse AMD models are critical to comprehending the significance of research findings and response to possible therapeutic options for dry AMD. Based on the multifactorial pathogenesis of AMD, murine dry AMD models can be classified into three groups. First, genetically engineered mice that target genes related to juvenile macular dystrophies are the most common models, and they include abcr(-/-) (Stargardt disease), transgenic ELOVL4 (Stargardt-3 dominant inheritary disease), Efemp1(R345W/R345W) (Doyne honeycomb retinal dystrophy), and Timp3(S156C/S156C) (Sorsby fundus dystrophy) mice. Other murine models target genes relevant to AMD, including inflammatory genes such as Cfh(-/-), Ccl2(-/-), Ccr2(-/-), Cx3cr1(-/-), and Ccl2(-/-)/cx3cr1(-/-), oxidative stress associated genes such as Sod1(-/-) and Sod2 knockdown, metabolic pathway genes such as neprilysin(-/-) (amyloid beta), transgenic mcd/mcd (cathepsin D), Cp(-/-)/Heph(-/Y) (ferroxidase ceruloplasmin/hepaestin, iron metabolism), and transgenic ApoE4 on high fat and high cholesterol diet (lipid metabolism). Second, mice have also been immunologically manipulated by immunization with carboxyethylpyrrole (CEP), an oxidative fragment of DHA found in drusen, and found to present with dry AMD features. Third, natural mouse strains such as arrd2/arrd2 (Mdm gene mutation) and the senescence accelerated mice (SAM) spontaneously develop features of dry AMD like photoreceptor atrophy and thickening of Bruch's membrane. All the aforementioned models develop retinal lesions with various features that simulate dry AMD lesions: focal photoreceptor degeneration, abnormal RPE with increased lipofuscin, basal infolding, decreased melanosomes and degeneration. However, Bruch's membrane changes are less common. Most mice develop retinal lesions at an older age (6-24 months, depending on the models), while the Ccl2(-/-)/cx3cr1(-/-) mice develop lesions by 4-6 weeks. Although murine models present various degrees of retinal and/or RPE degeneration, classical drusen is extremely rare. Using electron microscopy, small drusenoid deposits are found between RPE and Bruch's membrane in a few models including Efemp1(R345W/R345W), Ccl2(-/-)/cx3cr1(-/-), neprilysin(-/-), transgenic mcd/mcd, and ApoE4 transgenic mice on a high fat diet. High A2E levels are measured in the retinas of abcr(-/-), transgenic ELOVL4, and Ccl2(-/-)/cx3cr1(-/-) mice. In summary, murine models provide useful tools for studying AMD pathogenesis and evaluating novel therapies for this disease. This review compares the major dry AMD murine models and discusses retinal pathology at the ultrastructural level.
| S-EPMC2854213 | biostudies-literature
Project description:Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. There are two types of AMD: dry AMD and wet AMD. While laser-induced choroidal neovascularization has been used extensively in the studies of wet AMD by presenting the main features of human wet AMD, there was no established mouse model which fully recapitulates the cardinal features of human dry AMD. In this regard, lack of appropriate mouse model for dry AMD hampered the translational research on the pathogenesis and development of therapeutic agents. We recently suggested that 5XFAD mice could be a mouse model of dry AMD with regard to the amyloid beta (Aβ) related pathology. In this study, using transmission electron microscope, we analyzed ultrastructure of retinal pigment epithelium (RPE) of 5XFAD mice. Of importance, aged 5XFAD mice had ultrastructural changes of RPE and Bruchâs membrane compatible with cardinal features of dry AMD, including loss of apical microvilli and basal infolding of RPE, increased thickness of Bruchâs membrane, basal laminar and linear deposits, and accumulation of lipofuscin granules and undigested photoreceptor outer segment-laiden phagosomes. Using a threshold of 1.2 fold difference, we found â564â differentially expressed genes of which â190â were up-regulated and â374â were down-regulated in the RPE complex of aged 5XFAD mice. These altered genes were implicated in the pathogenesis of AMD including inflammation and immune response-related genes and retinol metabolism-related genes. Taken together, we suggest that aged 5XFAD mice can be used for dry AMD mouse model. All 5XFAD mice used were heterozygotes with respect to the transgene, and non-transgenic wild-type littermate (WT) mice served as controls.
2016-08-10 | E-GEOD-85408 | biostudies-arrayexpress
Project description:Age-related macular degeneration (AMD) is a progressive blinding disease and represents the leading cause of visual impairment in the aging population. AMD affects central vision which impairs one's ability to drive, read and recognize faces. There is no cure for this disease and current treatment modalities for the exudative form of the disease require repeated intravitreal injections which may be painful, are incompletely efficacious, and represent a significant treatment burden for both the patient and physician. As such, AMD represents a significant and important clinical problem.It is anticipated that in three years' time, 196 million individuals will be affected with AMD. Over 250 billion dollars per year are spent on care for AMD patients in the US. Over half of the heritability is explained by two major loci, thus AMD is considered the most well genetically defined of the complex disorders. A recent GWAS on 43,566 subjects identified novel loci and pathways associated with AMD risk, which has provided an excellent platform for additional functional studies. Genetic variants have been investigated, particularly with respect to anti-VEGF treatment, however to date, no pharmacogenomic associations have been consistently identified across these studies. It may be that if the goal of personalized medicine is to be realized and biomarkers are to have predictive value for determining the magnitude of risk for AMD at the genetic level, one will need to examine the relationships between these pathways across disease state and relative to modifiable risk factors such as hypertension, smoking, body mass index, and hypercholesterolemia. Further studies investigating protective alleles in populations with low AMD prevalence may lead to this goal.
| S-EPMC5886461 | biostudies-literature
Project description:Background/aimsNeovascular age-related macular degeneration (nAMD) is frequently bilateral, and previous reports on 'fellow eyes' have assumed sequential treatment after a period of treatment of the first eye only. The aim of our study was to analyse baseline characteristics and visual acuity (VA) outcomes of fellow eye involvement with nAMD, specifically differentiating between sequential and non-sequential (due to macular scarring in the first eye) antivascular endothelial growth factor treatment and timelines for fellow eye involvement.MethodsRetrospective, electronic medical record database study of the Moorfields AMD database of 6265 patients/120 286 single entries with data extracted between 21 October 2008 and 9 August 2018. The data set for analysis consisted of 1180 sequential, 807 non-sequential and 3410 unilateral eyes.ResultsMean VA (ETDRS letters±SD) of sequentially treated fellow eyes at baseline was significantly higher (63±13), VA gain over 2 years lower (0.37±14) and proportion of eyes with good VA (≥70 letters) higher (46%) than the respective first eyes (baseline VA 54±16, VA gain at 2 years 5.6±15, percentage of eyes with good VA 39%). Non-sequential fellow eyes showed baseline characteristics and VA outcomes similar to first eyes. Fellow eye involvement rate was 32% at 2 years, and median time interval to fellow eye involvement was 71 (IQR: 27-147) weeks.ConclusionThis report shows that sequentially treated nAMD fellow eyes have better baseline and final VA than non-sequentially treated eyes after 2 years of treatment. Sequentially treated eyes also had a greater proportion with good VA after 2 years.
| S-EPMC8204663 | biostudies-literature
Project description:Age-related macular degeneration (AMD), the most common form of irreversible blindness in the industrially developed world, can present years before a patient begins to lose vision. For most of these patients, AMD never progresses past its early stages to the advanced forms that are principally responsible for the vast majority of vision loss. Advanced AMD can manifest as either an advanced avascular form known as geographic atrophy (GA) marked by regional retinal pigment epithelium (RPE) cell death or as an advanced form known as neovascular AMD marked by the intrusion of fragile new blood vessels into the normally avascular retina. Physicians have several therapeutic interventions available to combat neovascular AMD, but GA has no approved effective therapies as of yet. In this chapter, we will discuss the current strategies for limiting dry AMD in patients. We will also discuss previous attempts at pharmacological intervention that were tested in a clinical setting and consider reasons why these putative therapeutics did not perform successfully in large-scale trials. Despite the number of unsuccessful past trials, new pharmacological interventions may succeed. These future therapies may aid millions of AMD patients worldwide.
| S-EPMC5472449 | biostudies-other
Project description:Age-related macular degeneration (AMD) is an expanding problem as longevity increases worldwide. While inflammation clearly contributes to vision loss in AMD, the mechanism remains controversial. Here we show that neutrophils are important in this inflammatory process. In the retinas of both early AMD patients and in a mouse model with an early AMD-like phenotype, we show neutrophil infiltration. Such infiltration was confirmed experimentally using ribbon-scanning confocal microscopy (RSCM) and IFNλ- activated dye labeled normal neutrophils. With neutrophils lacking lipocalin-2 (LCN-2), infiltration was greatly reduced. Further, increased levels of IFNλ in early AMD trigger neutrophil activation and LCN-2 upregulation. LCN-2 promotes inflammation by modulating integrin β1 levels to stimulate adhesion and transmigration of activated neutrophils into the retina. We show that in the mouse model, inhibiting AKT2 neutralizes IFNλ inflammatory signals, reduces LCN-2-mediated neutrophil infiltration, and reverses early AMD-like phenotype changes. Thus, AKT2 inhibitors may have therapeutic potential in early, dry AMD.
| S-EPMC6754381 | biostudies-literature
Project description:Age-related macular degeneration (AMD) is a complex, multifactorial and progressive retinal disease affecting millions of people worldwide. In developed countries, it is the leading cause of vision loss and legal blindness among the elderly. Although the pathogenesis of AMD is still barely understood, recent studies have reported that disorders in the regulation of the extracellular matrix (ECM) play an important role in its etiopathogenesis. The dynamic metabolism of the ECM is closely regulated by matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs). The present review focuses on the crucial processes that occur at the level of the Bruch's membrane, with special emphasis on MMPs, TIMPs, and the polymorphisms associated with increased susceptibility to AMD development. A systematic literature search was performed, covering the years 1990-2020, using the following keywords: AMD, extracellular matrix, Bruch's membrane, MMPs, TIMPs, and MMPs polymorphisms in AMD. In both early and advanced AMD, the pathological dynamic changes of ECM structural components are caused by the dysfunction of specific regulators and by the influence of other regulatory systems connected with both genetic and environmental factors. Better insight into the pathological role of MMP/TIMP complexes may lead to the development of new strategies for AMD treatment and prevention.
| S-EPMC7460693 | biostudies-literature
Project description:Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. There are two types of AMD: dry AMD and wet AMD. While laser-induced choroidal neovascularization has been used extensively in the studies of wet AMD by presenting the main features of human wet AMD, there was no established mouse model which fully recapitulates the cardinal features of human dry AMD. In this regard, lack of appropriate mouse model for dry AMD hampered the translational research on the pathogenesis and development of therapeutic agents. We recently suggested that 5XFAD mice could be a mouse model of dry AMD with regard to the amyloid beta (Aβ) related pathology. In this study, using transmission electron microscope, we analyzed ultrastructure of retinal pigment epithelium (RPE) of 5XFAD mice. Of importance, aged 5XFAD mice had ultrastructural changes of RPE and Bruch’s membrane compatible with cardinal features of dry AMD, including loss of apical microvilli and basal infolding of RPE, increased thickness of Bruch’s membrane, basal laminar and linear deposits, and accumulation of lipofuscin granules and undigested photoreceptor outer segment-laiden phagosomes. Using a threshold of 1.2 fold difference, we found “564” differentially expressed genes of which “190” were up-regulated and “374” were down-regulated in the RPE complex of aged 5XFAD mice. These altered genes were implicated in the pathogenesis of AMD including inflammation and immune response-related genes and retinol metabolism-related genes. Taken together, we suggest that aged 5XFAD mice can be used for dry AMD mouse model.
2016-08-10 | GSE85408 | GEO
Project description:Age related macular degeneration (AMD) is the leading cause of blindness in individuals older than 65 years of age. It is a multifactorial disorder and identification of risk factors enables individuals to make lifestyle choices that may reduce the risk of disease. Collaboration between geneticists, ophthalmologists, and optometrists suggests that genetic risk factors play a more significant role in AMD than previously thought. The most important genes are associated with immune system modulation and the complement system, e.g., complement factor H (CFH), factor B (CFB), factor C3, and serpin peptidase inhibitor (SERPING1). Genes associated with membrane transport, e.g., ATP-binding cassette protein (ABCR) and voltage-dependent calcium channel gamma 3 (CACNG3), the vascular system, e.g., fibroblast growth factor 2 (FGF2), fibulin-5, lysyl oxidase-like gene (LOXL1) and selectin-P (SELP), and with lipid metabolism, e.g., apolipoprotein E (APOE) and hepatic lipase (LIPC) have also been implicated. In addition, several other genes exhibit some statistical association with AMD, e.g., age-related maculopathy susceptibility protein 2 (ARMS2) and DNA excision repair protein gene (ERCC6) but more research is needed to establish their significance. Modifiable risk factors for AMD should be discussed with patients whose lifestyle and/or family history place them in an increased risk category. Furthermore, calculation of AMD risk using current models should be recommended as a tool for patient education. It is likely that AMD management in future will be increasingly influenced by assessment of genetic risk as such screening methods become more widely available.
| S-EPMC3880448 | biostudies-other
Project description:Aging contributes to the risk of development of ocular diseases including, but not limited to, Age-related Macular Degeneration (AMD) that is a leading cause of blindness in the United States as well as worldwide. Retinal aging, that contributes to AMD pathogenesis, is characterized by accumulation of drusen deposits, alteration in the composition of Bruch's membrane and extracellular matrix, vascular inflammation and dysregulation, mitochondrial dysfunction, and accumulation of reactive oxygen species (ROS), and subsequent retinal pigment epithelium (RPE) cell senescence. Since there are limited options available for the prophylaxis and treatment of AMD, new therapeutic interventions are constantly being looked into to identify new therapeutic targets for AMD. This review article discusses the potential candidates for AMD therapy and their known mechanisms of cytoprotection in AMD. These target therapeutic candidates include APE/REF-1, MRZ-99030, Ciliary NeuroTrophic Factor (CNTF), RAP1 GTPase, Celecoxib, and SS-31/Elamipretide.
| S-EPMC8464988 | biostudies-literature