Onset Of Age-related Macular Degeneration Research Articles

Complement Factor H Loss in RPE Cells Causes Retinal Degeneration in a Human RPE-Porcine Retinal Explant Co-Culture Model.

Age-related Macular degeneration (AMD) is a degenerative disease of the macula affecting the elderly population. Treatment options are limited, partly due to the lack of understanding of AMD pathology and the lack of suitable research models that replicate the complexity of the human macula and the intricate interplay of the genetic, aging and lifestyle risk factors contributing to AMD. One of the main genetic risks associated with AMD is located on the Complement Factor H (CFH) gene, leading to an amino acid substitution in the Factor H (FH) protein (Y402H). However, the mechanism of how this FH variant promotes the onset of AMD remains unclear. Previously, we have shown that FH deprivation in RPE cells, via CFH silencing, leads to increased inflammation, metabolic impairment and vulnerability toward oxidative stress. In this study, we established a novel co-culture model comprising CFH silenced RPE cells and porcine retinal explants derived from the visual streak of porcine eyes, which closely resemble the human macula. We show that retinae exposed to FH-deprived RPE cells show signs of retinal degeneration, with rod cells being the first cells to undergo degeneration. Moreover, via Raman analyses, we observed changes involving the mitochondria and lipid composition of the co-cultured retinae upon FH loss. Interestingly, the detrimental effects of FH loss in RPE cells on the neuroretina were independent of glial cell activation and external complement sources. Moreover, we show that the co-culture model is also suitable for human retinal explants, and we observed a similar trend when RPE cells deprived of FH were co-cultured with human retinal explants from a single donor eye. Our findings highlight the importance of RPE-derived FH for retinal homeostasis and provide a valuable model for AMD research.

MicroRNA-27a Promotes Oxidative-Induced RPE Cell Death through Targeting FOXO1.

Age-related macular degeneration (AMD) is a multifactor disease, which is primarily characterized by retinal pigment epithelium (RPE) cell loss. Since the retina is the most metabolically active tissue, RPE cells are exposed to consistent oxidative environment. So, oxidation-induced RPE cell death has long been considered a contributor to the onset of AMD. Here, we applied a retinal degeneration (RD) rat model induced by blue light-emitting diode (LED) and a cell model constructed by H2O2 stimulus to mimic the prooxidant environment of the retina. We detected that the expression of miR-27a was upregulated and the expression of FOXO1 was downregulated in both models. So, we furtherly investigated the role of miR-27a-FOXO1 axis in RPE in protesting against oxidants. Lentivirus-mediated RNA was injected intravitreally into rats to modulate the miR-27a-FOXO1 axis. Retinal function and histopathological changes were evaluated by electroretinography (ERG) analysis and hematoxylin and eosin (H&E) staining, respectively. Massive photoreceptor and RPE cell death were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The damage to the retina was aggravated in the FOXO1 gene-knockdown and miR-27a-overexpression groups after exposure to LED but was alleviated in the FOXO1 gene-overexpression or miR-27a-knockdown groups. Dual luciferase assay was used to detect the binding site of miR-27a and FOXO1. Upregulated miR-27a inhibited the expression of FOXO1 by directly binding to the FOXO1 mRNA 3′UTR and decreased the autophagy activity of ARPE-19 cells, resulting in the accumulation of reactive oxygen species (ROS) and decrease of cell viability. The results suggest that miR-27a is a negative regulator of FOXO1. Also, our data emphasize the prominent role of miR-27a/FOXO1 axis in modulating ROS accumulation and cell death in RPE cell model under oxidative stress and influencing the retinal function in the LED-induced RD rat model.

Mitochondria dynamics in the aged mice eye and the role in the RPE phagocytosis

Aging is a predominant risk factor for various eye diseases. Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, and its etiology remains unclear. Fragmented and dysfunctional mitochondria are associated with age-related diseases. The retinal pigment epithelium (RPE), a polarized cell layer that functions in visual pigment recycling and degeneration, is suspected as the primary region site of AMD. In the present study, we investigated the relationship between mitochondrial dysfunction and RPE aging. Compared to young mice, aged pigmented mice (C57BL/6J, 12-month-old) exhibit decreased visual function without retinal thinning. Consistently, the rhodopsin expression level decreased in the outer segment of aged mice. Moreover, the cell volume of the RPE increased in aged animals. Interestingly, the expression of mitochondria dynamics-related proteins, including Drp1, was altered in the RPE-choroid complex but not in the neural retina after aging. Electron microscopy revealed that mitochondrial size decreased and cristae width increased in aged RPE. The photoreceptor outer segment (POS) treatment of ARPE-19 cells causes Drp1 activation. Furthermore, pharmacological suppression of mitochondrial fission improved the phagocytosis of the POS. These findings indicate that mitochondrial dysfunction and fission in RPE impede phagocytosis and cause retardation of the visual cycle, which can be one of the age-related defects in the retina that may contribute to the onset of AMD.

Oxidative stress in retinal pigment epithelium impairs stem cells: a vicious cycle in age-related macular degeneration.

Aging, chronic oxidative stress, and inflammation are major pathogenic factors in the development and progression of age-related macular degeneration (AMD) with the loss of retinal pigment epithelium (RPE). The human RPE contains a subpopulation of progenitors (i.e., RPE stem cells-RPESCs) whose role in the RPE homeostasis is under investigation. We evaluated the paracrine effects of mature RPE cells exposed to oxidative stress (H2O2) on RPESCs behavior through co-cultural, morphofunctional, and bioinformatic approaches. RPESCs showed a decline in proliferation, an increase of the senescence-associated β-galactosidase activity, the acquisition of a senescent-like secretory phenotype (SASP), and the reduction of their stemness and differentiationcompetencies. IL-6 and Superoxide Dismutase 2 (SOD2) seem to be key molecules in RPESCs response to oxidative stress. Our results get insight into stress-induced senescent-associated molecular mechanisms implicated in AMD pathogenesis. The presence of chronic oxidative stress in the microenvironment reduces the RPESCs abilities, inducing and/or maintaining a pro-inflammatory retinal milieu that in turn could affect AMD onset and progression.

LXA4 protects against blue-light induced retinal degeneration in human A2E-laden RPE cells and Balb-c mice.

BackgroundAge-related macular degeneration (AMD) is one of the leading causes of permanent visual impairment in the elderly. Blue light (BL) has been reported to cause retinal damage and contribute to the onset and development of severe AMD. N-retinylidene-N-retinylethanolamine (A2E), a lipofuscin fluorophore, accumulates with ageing in the retinal pigment epithelium (RPE) cells. Once exposed to BL, A2E easily oxidizes to A2E-epoxides, causing oxidative-stress injury to the retina. Lipoxin A4 (LXA4), an endogenous anti-antioxidant lipid, plays a key role in multiple organs by binding to the formyl-peptide receptor-like 1 (FPRL1). This study examined the protective effects of LXA4 on oxidative–stress injury induced by BL exposure, and clarified the underlying mechanisms in cultured RPE cells and Balb-c mice.MethodsLXA4 diluent was orally administered to mice before retinal degeneration was established. Optical coherence tomography, retinal histology, and RPE cell injury were assessed.ResultsLXA4 administration significantly ameliorated retinal damage as evidenced by the thicknesses of the retinal layers and the tight junctions of RPE cells in vivo. LXA4 inhibited BL-induced reactive oxygen species (ROS) production, reduced tight junctions, and the death of A2E-laden RPE cells. LXA4 also potently increased the expression of haem oxygenase-1 (HO1) and NAD(P)H quinone oxidoreductase 1 (NQO1), probably by decreasing the association between nuclear factor erythroid 2-related factor 2 (NRF2) and Kelch-like ECH (Epichlorohydrin) -associated protein 1 (Keap1), and ameliorating NRF2 nuclear translocation and the antioxidant response element (ARE) deoxyribonucleic acid (DNA) binding activity.ConclusionsOur results showed that LXA4 ameliorated retinal degeneration, and should be considered in the prevention and treatment of AMD.

Prevention of the Onset of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) represents the leading cause of irreversible blindness in elderly people, mostly after the age of 65. The progressive deterioration of visual function in patients affected by AMD has a significant impact on quality of life and has also high social costs. The current therapeutic options are only partially able to slow down the natural course of the disease, without being capable of stopping its progression. Therefore, better understanding of the possibilities to prevent the onset of the disease is needed. In this regard, a central role is played by the identification of risk factors, which might participate to the development of the disease. Among these, the most researched are dietary risk factors, lifestyle, and light exposure. Many studies showed that a higher dietary intake of nutrients, such as lutein, zeaxanthin, beta carotene, omega-3 fatty acids and zinc, reduced the risk of early AMD. Regarding lifestyle habits, the association between smoking and AMD is currently accepted. Finally, retinal damage caused by ultraviolet rays and blue light is also worthy of attention. The scope of this review is to summarize the present knowledge focusing on the measures to adopt in order to prevent the onset of AMD.

Overflow phenomenon in serum lutein after supplementation: a systematic review supported with SNPs analyses.

Lutein, a type of carotenoids, is found to delay the onset and progression of age-related macular degeneration (AMD). Several lutein supplementation studies showed that after an initial increase, lutein serum levels demonstrated a subsequent decrease despite continuous supplementation. In this systematic literature review, this obscure phenomenon was tried to be explained. The subsequent drop in lutein levels was postulated due to down-regulation of lutein receptors scavenger receptor class B type I (SR-BI) in the gastrointestinal tract, upregulation of lutein degrading enzyme β-carotene dioxygenase (BCDO2), or perhaps a combination of both. Some single nucleotides polymorphisms (SNPs) that could have influence on the occurrence of this phenomenon. To date, an exact scientific explanation for this phenomenon has not been established. Further research is needed to investigate this phenomenon in depth to reach an irrefutable explanation, giving that lutein is proven to be effective in delaying the onset and progression of AMD and its metabolism in the human body becomes of equal importance.

Retinal tissue develops an inflammatory reaction to tobacco smoke and electronic cigarette vapor in mice

Cigarette smoke has been identified as a major risk factor for the development of age-related macular degeneration (AMD). As an alternative to conventional cigarettes (C-cigarette), electronic cigarettes (E-cigarette) have been globally promoted and are currently widely used. The increasing usage of E-cigarettes raises concerns with regard to short- (2 weeks), medium- (3 months), and long- (8 months) term consequences related to retinal tissue. In this report, a controlled study in mouse models was conducted to probe the comprehensive effects of E-cigarette vapor on retina, retinal pigmented epithelium (RPE), and choroidal tissues by (1) comparing the effects of C-cigarette smoke and E-cigarette vapor on retina separately and (2) determining the effects of E-cigarette vapor on the RPE and analyzing the changes with regard to inflammatory (IL-1β, TNFα, iNOS) and angiogenic (VEGF, PEDF) mediators in retina/RPE/choroid by ELISA assays. The data showed that C-cigarette smoke exposure promoted an inflammatory reaction in the retina in vivo. Mice exposed to E-cigarette (nicotine-free) vapor developed inflammatory and angiogenic reactions more pronounced in RPE and choroid as compared to retinal tissue, while nicotine-containing E-cigarette vapor caused even a more serious reaction. Both inflammatory and pro-angiogenic reactions increased with the extension of exposure time. These results demonstrate that exposure to C-cigarette smoke is harmful to the retina. Likewise, the exposure to E-cigarette vapor (with or without nicotine) increases the occurrence and progression of inflammatory and angiogenic stimuli in the retina, which might also be related to the onset of wet AMD in humans.Key messagesC-cigarette smoke exposure promotes an inflammatory reaction in the retina in vivo.Mice exposed to E-cigarette (nicotine-free) vapor develop inflammatory and angiogenic reactions more pronounced in RPE and choroid compared to retinal tissue, while nicotine-containing E-cigarette vapor causes even a more serious reaction.Both inflammatory and pro-angiogenic reactions increase with the extension of E-cigarette vapor exposure time.

Metformin, A Potential Role in Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis.

BackgroundCurrently, no generally approved medical treatment can delay the onset of age-related macular degeneration (AMD) or slow the progression of degenerative changes. Repurposing drugs with beneficial effects on AMD pathophysiology offers a route to new treatments which is faster, cost-effective, and safer for patients. Recent studies indicate a potential role for metformin in delaying AMD development and progression. In this context, we conducted a systematic review and meta-analysis to look for beneficial associations between metformin and AMD.MethodsWe systematically searched Medline and Embase (via Ovid), Web of Science, and ClinicalTrials.gov databases for clinical studies in humans that examined the associations between metformin treatment and AMD published from inception to February 2021. We calculated pooled odds ratio (OR) with 95% confidence interval (CI) considering a random effect model in the meta-analysis.ResultsFive retrospective studies met the inclusion criteria. There are no prospective studies that have reported the effect of metformin in AMD. The meta-analysis showed that people taking metformin were less likely to have AMD although statistical significance was not met (pooled adjusted OR = 0.80, 95% CI 0.54–1.05, I2 = 98.8%). Subgroup analysis of the association between metformin and early and late AMD could not be performed since the data was not available from the included studies.ConclusionsAnalysis of retrospective data suggests a signal that metformin may be associated with decreased risk of any AMD. It should be interpreted with caution because of the failure to meet statistical significance, the small number of studies, and the limitation of routine record data. However prospective studies are warranted in generalizable populations without diabetes, of varied ethnicities, and AMD stages. Clinical trials are needed to determine if metformin has efficacy in treating early and late-stage AMD.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-021-00344-3.

The need to investigate hyperuricemia as a factor in the onset of age-related macular degeneration.

The need to investigate hyperuricemia as a factor in the onset of age-related macular degeneration.

Are Current Methods of Measuring Dark Adaptation Effective in Detecting the Onset and Progression of Age-Related Macular Degeneration? A Systematic Literature Review.

IntroductionDark adaptation (DA) has been proposed as a possible functional biomarker for age-related macular degeneration (AMD). In this systematic review we aim to evaluate current methodology used to assess DA in people with AMD, the evidence of precision in detecting the onset and progression of AMD, and the relationship between DA and other functional and structural measures.MethodsMEDLINE, EMBASE, CINAHL, AMED, PsycINFO, PsycARTICLES were searched for studies published between January 2006 and January 2020 that assessed DA in people with AMD. Details of eligible studies including study design, characteristics of study population and outcomes were recorded. All included studies underwent quality appraisal using approved critical appraisal tools. This systematic review follows PRISMA guidelines (PROSPERO registration number: CRD42019129486).ResultsForty-eight studies were eligible for inclusion, reporting a variety of instruments and protocols to assess different DA parameters. Twenty of these studies used the AdaptDx (MacuLogix, Hummelstown, PA, USA) instrument and assessed rod-intercept time (RIT). Most of these reported that RIT was delayed in people with AMD and this delay worsened with AMD severity. Four studies, involving 533 participants, reported estimates of diagnostic performance of AdaptDx to separate people with AMD from visually healthy controls. DA has been compared to other measures of visual function, patient-reported outcome measures (PROMs) and structural measures. Ten studies specifically considered evidence that the presence of certain structural abnormalities was associated with impaired DA in AMD.ConclusionsThis systematic review indicates overwhelming evidence of reasonable quality for an association between impaired DA and AMD. Data on the repeatability and reproducibility of DA measurement are sparse. There is evidence that structural abnormalities such as reticular drusen are associated with prolongation of DA time. Fewer studies have explored an association between DA and other measures of visual function or PROMs. We found no studies that had compared DA with performance-based measures.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-020-00323-0.

The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration

The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch’s membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.

Pinosylvin Extract Retinari™ Sustains Electrophysiological Function, Prevents Thinning of Retina, and Enhances Cellular Response to Oxidative Stress in NFE2L2 Knockout Mice.

Chronic oxidative stress eventually leads to protein aggregation in combination with impaired autophagy, which has been observed in age-related macular degeneration. We have previously shown an effective age-related macular degeneration disease model in mice with nuclear factor-erythroid 2-related factor-2 (NFE2L2) knockout. We have also shown pinosylvin, a polyphenol abundant in bark waste, to increase human retinal pigment epithelium cell viability in vitro. In this work, the effects of commercial natural pinosylvin extract, Retinari™, were studied on the electroretinogram, optical coherence tomogram, autophagic activity, antioxidant capacity, and inflammation markers. Wild-type and NFE2L2 knockout mice were raised until the age of 14.8 ± 3.8 months. They were fed with either regular or Retinari™ chow (141 ± 17.0 mg/kg/day of pinosylvin) for 10 weeks before the assays. Retinari™ treatment preserved significant retinal function with significantly preserved a- and b-wave amplitudes in the electroretinogram responses. Additionally, the treatment prevented thinning of the retina in the NFE2L2 knockout mice. The NFE2L2 knockout mice showed reduced ubiquitin-tagged protein accumulation in addition to local upregulation of complement factor H and antioxidant enzymes superoxide dismutase 1 and catalase. Therefore, the treatment in the NFE2L2 KO disease model led to reduced chronic oxidative stress and sustained retinal function and morphology. Our results demonstrate that pinosylvin supplementation could potentially lower the risk of age-related macular degeneration onset and slow down its progression.

Mechanisms of mitochondrial dysfunction and their impact on age-related macular degeneration.

Oxidative stress-induced damage to the retinal pigment epithelium (RPE) is considered to be a key factor in age-related macular degeneration (AMD) pathology. RPE cells are constantly exposed to oxidative stress that may lead to the accumulation of damaged cellular proteins, lipids, nucleic acids, and cellular organelles, including mitochondria. The ubiquitin-proteasome and the lysosomal/autophagy pathways are the two major proteolytic systems to remove damaged proteins and organelles. There is increasing evidence that proteostasis is disturbed in RPE as evidenced by lysosomal lipofuscin and extracellular drusen accumulation in AMD. Nuclear factor-erythroid 2-related factor-2 (NFE2L2) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) are master transcription factors in the regulation of antioxidant enzymes, clearance systems, and biogenesis of mitochondria. The precise cause of RPE degeneration and the onset and progression of AMD are not fully understood. However, mitochondria dysfunction, increased reactive oxygen species (ROS) production, and mitochondrial DNA (mtDNA) damage are observed together with increased protein aggregation and inflammation in AMD. In contrast, functional mitochondria prevent RPE cells damage and suppress inflammation. Here, we will discuss the role of mitochondria in RPE degeneration and AMD pathology focused on mtDNA damage and repair, autophagy/mitophagy signaling, and regulation of inflammation. Mitochondria are putative therapeutic targets to prevent or treat AMD.

Association Between Monocyte Chemotactic Protein 1 Variants and Age-Related Macular Degeneration Onset Among Chinese People.

BackgroundWe assessed the potential association between monocyte chemotactic protein 1 (MCP-1) variants (rs1024611 and rs3760396) and age-related macular degeneration (AMD) susceptibility among Chinese Han people.Material/MethodsOur research included 129 AMD patients and 131 healthy controls. Genotyping for MCP-1 variants was performed in the 2 groups, and genotype and allele distributions were checked between groups by χ2 analysis. Odds ratio (OR) and 95% confidence interval (CI) reflected the potential association between MCP-1 variants and AMD risk. The linkage disequilibrium of polymorphisms was detected using Haploview.ResultsSignificant differences in rs1024611 genotype distributions were detected between the 2 groups, and homozygous carriers with GG genotype had higher AMD incidence (P<0.05, OR=2.650, 95% CI=1.127–6.231). The rs1024611 G allele frequency was significantly higher in AMD patients, suggesting that the G allele promotes AMD onset (P<0.05, OR=1.447, 95% CI=1.013–2.068). Strong linkage disequilibrium was found between rs1024611 and rs3760396, and haplotype Ars1024611–Crs3760396 was significantly associated with decreased risk of AMD (P=0.001, OR=0.502, 95% CI=0.335–0.752).ConclusionsMCP-1 rs1024611 variant appears to contribute to risk of AMD in the Chinese Han population, and the interaction of MCP-1 polymorphisms may also influence individual susceptibility to AMD.

Protective effect of Prunella vulgaris var. L extract against blue light induced damages in ARPE-19 cells and mouse retina

Age-related macular degeneration (AMD) is one of leading causes that induce severe visual impairment and loss in the elderly. Previous studies have suggested that blue light (BL) could induce retinal degeneration, which is a major cause of the onset and development of severe AMD. In the retinal pigment epithelium (RPE) cells, A2E, a lipofuscin fluorophore, is accumulated with aging. When A2E is exposed to BL, it is easily oxidized to A2E-epoxides, leading to oxidative stress and inflammatory response in retina. The aim of this study was to investigate protective effect of Prunella vulagris (P.V) extract against oxidative stress and inflammation caused by BL, and to elucidate the underlying mechanisms in the cultured RPE cells and balb-c mice. In both model studies, P.V extract activated NF-E2 related factor 2 (Nrf-2)/hemeoxygenase-1 (HO-1) signaling pathway, followed by inhibition of ROS/MDA production, GSH depletion and reduction in SOD activity. Furthermore, P.V extract inhibited upregulation of inflammatory related genes (interlukin (IL)-1beta, IL-6, monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor A (VEGF A)) and BL induced RPE cell death, determined by cell viability and histological analyses. The mechanism of protection against inflammation by P.V extract involves inhibition of nuclear translocation of nuclear factor kappa beta (NF-kB) along with degradation of NF-kB inhibitor alpha (IkB alpha). The results suggest that P.V extract could be a potential intervention to prevent the onset and development of severe AMD.

Toxic effects of A2E in human ARPE-19 cells were prevented by resveratrol: a potential nutritional bioactive for age-related macular degeneration treatment.

Age-related macular degeneration (AMD) is a late-onset retinal disease and the leading cause of central vision loss in the elderly. Degeneration of retinal pigment epithelial cells (RPE) is a crucial contributing factor responsible for the onset and progression of AMD. The toxic fluorophore N-retinyl-N-retinylidene ethanolamine (A2E), a major lipofuscin component, accumulates in RPE cells with age. Phytochemicals with antioxidant properties may have a potential role in both the prevention and treatment of this age-related ocular disease. Particularly, there is an increased interest in the therapeutic effects of resveratrol (RSV), a naturally occurring polyphenol (3,4',5-trihydroxystilbene). However, the underlying mechanism of the RSV antioxidative effect in ocular diseases has not been well explored. We hypothesized that this bioactive compound may have beneficial effects for AMD. To this end, to investigate the potential profits of RSV against A2E-provoked oxidative damage, we used human RPE cell line (ARPE-19). RSV (25µM) attenuates the cytotoxicity and the typical morphological characteristics of apoptosis observed in 25µM A2E-laden cells. RSV pretreatment strengthened cell monolayer integrity through the preservation of the transepithelial electrical resistance and reduced the fluorescein isothiocyanate (FITC)-dextran diffusion rate as well as cytoskeleton architecture. In addition, RSV exhorts protective effects against A2E-induced modifications in the intracellular redox balance. Finally, RSV also prevented A2E-induced mitochondrial network fragmentation. These findings reinforce the idea that RSV represents an attractive bioactive for therapeutic intervention against ocular diseases associated with oxidative stress such as AMD.

Neutrophils as an important pathophysiologic cellular component in the onset of AMD

AbstractVision loss from age‐related macular degeneration (AMD) is an expanding, major unmet problem due to the aging population worldwide. Inflammation has emerged as a potential cause of AMD, but how inflammation contributes to vision loss in AMD remains controversial despite intensive study around the world. Herein, we identify inflammatory signals that drive neutrophil infiltration into the retinas of early AMD patients and the Cryba1 conditional knockout mouse model that mimics an early AMD‐like phenotype. Specifically, we observed increased levels of IFNλ in early AMD that triggered neutrophil activation and lipocalin‐2 (LCN‐2) upregulation in these cells. NOD‐SCID immune‐deficient mice were injected intravenously with IFNλ activated bone marrow‐derived normal neutrophils labeled with red CMTPX dye. Ribbon‐scanning confocal microscopy (RSCM) of benzyl alcohol benzyl benzoate (BABB) cleared eyes, showed homing of neutrophils into the eye. In contrast, mice injected with IFNλ activated LCN‐2‐/‐ neutrophils showed fewer cells infiltrating the eye. LCN‐2 promotes inflammation and AMD‐like pathology by interacting with Disabled homolog2 (Dab2) and modulating integrin β1 levels to stimulate adhesion and transmigration of activated IL‐28R1 (IFNλ receptor) positive neutrophils into the retina. Inhibiting AKT2‐dependent signaling in the mouse model neutralizes IFNλ inflammatory signals, reducing LCN‐2‐mediated neutrophil infiltration into the retina and reversing early AMD‐like phenotype changes, thereby providing a potential therapeutic target for early AMD.

Pilot study of homeostatic alterations of mineral elements in serum of patients with age-related macular degeneration via elemental and isotopic analysis using ICP-mass spectrometry

Age-related macular degeneration (AMD), the main cause of irreversible blindness in people over 60 years of age, is an eye disease that evolves with loss of central vision. Although AMD manifests itself in the eye, blood is continuously flowing through the macular region, such that potential alterations in this region could be reflected in the composition of whole blood or plasma/serum. Therefore, the potential clinical relevance of analysis of serum samples was assessed because of the low degree of invasiveness of blood sampling. 40 initial samples (20 from controls and 20 from patients with the dry form of AMD) have been analysed in this work to investigate the possible occurrence of homeostatic alterations of essential mineral elements caused by the disease. Both major (Na, Mg, P and K) and trace (Fe, Cu and Zn) essential mineral elements were determined in blood serum using single-collector ICP-mass spectrometry. Also, the isotopic composition of Cu (an element proposed to be directly involved in the onset of AMD) was determined using multi-collector ICP-mass spectrometry. Unexpected light Cu isotopic compositions in three individuals assumed as controls, resulted in a re-evaluation of their clinical information and a later exclusion due to pathologies initially not accounted for. In this pilot study, a significant alteration in the δ65Cu value has been found between the two final cohorts (AMD patients: n = 20; controls n = 17), with lower δ65Cu values (i.e. an enrichment in the light 63Cu isotope) in the case of AMD. Also, higher serum concentrations of the elements P and Zn were established in AMD at a systemic level.

Protective effects of quercetin-3-O-α-l-arabinopyranoside against UVA induced apoptosis via regulating inflammatory pathways in ARPE-19 cells and Balb/c mice

Abstract Accumulation of N-retinylidene-N-retinylethanolamine (A2E) and light exposure are known to be intensely involved in the progression of age-related macular degeneration (AMD). It has been demonstrated that when A2E was exposed to light, oxidative byproducts of A2E (oxo-A2E) are generated, causing cell death. We aimed to investigate the effects of quercetin-3-O-α- l -arabinopyranoside (QA) on ultraviolet A (UVA) exposure in human retinal pigment epithelial cells (ARPE-19 cells) and retinas of balb/c mice. This study demonstrated that QA inhibited translocation of NF-kB and upregulations of inflammatory related genes such as IL-1β, IL-6, MCP-1, CXCL-2, and VEGF-A, significantly increased by UVA exposure. In addition, QA prevented UVA induced apoptosis through decreasing caspase 3 activation and PARP cleavage both in APRE-19 cells and in retinas. Taken together, our study demonstrated the protective effects of QA on UVA induced apoptosis, suggesting that QA could be a potential agent to prevent onset and progression of AMD.