Ischemic Choroidal Diseases

2021 ◽  
Author(s):  
Teresa Barth ◽  
Horst Helbig
Keyword(s):  
Lupus Erythematosus ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Enhanced Depth Imaging ◽  
Vascular Structure ◽  
Drug Induced ◽  
Choroidal Blood Flow ◽  
Age Related ◽  
Choroidal Ischemia

Abstract Introduction Ischemic choroidal diseases are an underdiagnosed entity. The clinical pattern varies according to the size and the localisation of the affected vascular structure. Clinical Presentation In eyes with occlusion of the long posterior ciliary arteries, characteristic triangular patches of choroidal ischemia (Amalric sign) are seen, which in the course of time merge into well-defined areas of atrophy of the retinal pigment epithelium. Above the non-perfused choroidal areas, hyperpigmented, grouped lines appear (Siegrist streaks). Circumscribed ischemia of smaller choroidal arterioles and capillary vessels appears as multifocal, yellowish lesions in the posterior fundus (Elschnig spots). Vortex vein occlusion becomes manifest as exudative haemorrhagic choroidal swelling in the periphery. Causes of Choroidal Ischemia Apart from arterial hypertension as a major risk factor, some immunological disorders such as giant cell arteritis and systemic lupus erythematosus and haematological pathologies also affect choroidal perfusion. Furthermore, choroidal ischemia occurs due to local inflammation, as found in eyes with acute multifocal posterior placoid pigment epitheliopathy (APMPPE). Rarely, choroidal infarction is of iatrogenic origin or drug-induced. Recent advances in imaging, such as the introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) and OCT angiography (OCT-A), have improved the visualisation of the choroidal vasculature and complement the classical angiographic procedures. In patients with age-related macular degeneration (AMD) and diabetes, some changes in choroidal blood flow and vascular structure have also been noted. While in AMD the choroidal pathologies correlate with the disease progression and the functional prognosis, the pathophysiological relationship between diabetic choroidopathy and retinopathy is currently unclear. Management and Conclusion With regard to the limited therapeutic options for choroidal ischemia, optimisation of the cardiovascular risk profile and the management of accompanying ocular and systemic diseases are essential.

scholarly journals Oxidative and Nitrosative Stress in Age-Related Macular Degeneration: A Review of Their Role in Different Stages of Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 653
Author(s):  
Caterina Toma ◽  
Stefano De Cillà ◽  
Aurelio Palumbo ◽  
Divya Praveen Garhwal ◽  
Elena Grossini
Keyword(s):  
Macular Degeneration ◽  
Nitrosative Stress ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Choroidal Blood Flow ◽  
Oxidative And Nitrosative Stress ◽  
In Vivo Models ◽  
Altered Expression ◽  
Age Related

Although the exact pathogenetic mechanisms leading to age-related macular degeneration (AMD) have not been clearly identified, oxidative damage in the retina and choroid due to an imbalance between local oxidants/anti-oxidant systems leading to chronic inflammation could represent the trigger event. Different in vitro and in vivo models have demonstrated the involvement of reactive oxygen species generated in a highly oxidative environment in the development of drusen and retinal pigment epithelium (RPE) changes in the initial pathologic processes of AMD; moreover, recent evidence has highlighted the possible association of oxidative stress and neovascular AMD. Nitric oxide (NO), which is known to play a key role in retinal physiological processes and in the regulation of choroidal blood flow, under pathologic conditions could lead to RPE/photoreceptor degeneration due to the generation of peroxynitrite, a potentially cytotoxic tyrosine-nitrating molecule. Furthermore, the altered expression of the different isoforms of NO synthases could be involved in choroidal microvascular changes leading to neovascularization. The purpose of this review was to investigate the different pathways activated by oxidative/nitrosative stress in the pathogenesis of AMD, focusing on the mechanisms leading to neovascularization and on the possible protective role of anti-vascular endothelial growth factor agents in this context.

scholarly journals Recent advances in the management of dry age-related macular degeneration: A review

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 245 ◽  
Author(s):  
Francesco Bandello ◽  
Riccardo Sacconi ◽  
Lea Querques ◽  
Eleonora Corbelli ◽  
Maria Vittoria Cicinelli ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Vision Loss ◽  
Morphological Changes ◽  
Pigment Epithelium ◽  
Fundus Autofluorescence ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Choroidal Blood Flow ◽  
Age Related

Age-related macular degeneration (AMD), the most important cause of vision loss in elderly people, is a degenerative disorder of the central retina with a multifactorial etiopathology. AMD is classified in dry AMD (d-AMD) or neovascular AMD depending on the presence of choroidal neovascularization. Currently, no therapy is approved for geographic atrophy, the late form of d-AMD, because no treatment can restore the damage of retinal pigment epithelium (RPE) or photoreceptors. For this reason, all treatment approaches in d-AMD are only likely to prevent and slow down the progression of existing atrophy. This review focuses on the management of d-AMD and especially on current data about potential targets for therapies evaluated in clinical trials. Numerous examinations are available in clinics to monitor morphological changes in the retina, RPE and choroid of d-AMD patients. Fundus autofluorescence and optical coherence tomography (OCT) are considered the most useful tools in the diagnosis and follow-up of d-AMD alterations, including the monitoring of atrophy area progression. Instead, OCT-angiography is a novel imaging tool that may add further information in patients affected by d-AMD. Several pathways, including oxidative stress, deposits of lipofuscin, chronic inflammation and choroidal blood flow insufficiency, seem to play an important role in the pathogenesis of d-AMD and represent possible targets for new therapies. A great number of treatments for d-AMD are under investigation with promising results in preliminary studies. However, only few of these drugs will enter the market, offering a therapeutic chance to patients affected by the dry form of AMD and help them to preserve a good visual acuity. Further studies with a long-term follow-up would be important to test the real safety and efficacy of drugs under investigation.

scholarly journals Nanocarriers, Progenitor Cells, Combinational Approaches, and New Insights on the Retinal Therapy

2021 ◽  
Vol 22 (4) ◽  
pp. 1776
Author(s):  
Elham Pishavar ◽  
Hongrong Luo ◽  
Johanna Bolander ◽  
Antony Atala ◽  
Seeram Ramakrishna
Keyword(s):  
Drug Delivery ◽  
Progenitor Cells ◽  
Transfection Efficiency ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Therapeutic Approaches ◽  
Age Related ◽  
Nanofibrous Scaffolds ◽  
The Stability

Progenitor cells derived from the retinal pigment epithelium (RPECs) have shown promise as therapeutic approaches to degenerative retinal disorders including diabetic retinopathy, age-related macular degeneration and Stargardt disease. However, the degeneration of Bruch’s membrane (BM), the natural substrate for the RPE, has been identified as one of the major limitations for utilizing RPECs. This degeneration leads to decreased support, survival and integration of the transplanted RPECs. It has been proposed that the generation of organized structures of nanofibers, in an attempt to mimic the natural retinal extracellular matrix (ECM) and its unique characteristics, could be utilized to overcome these limitations. Furthermore, nanoparticles could be incorporated to provide a platform for improved drug delivery and sustained release of molecules over several months to years. In addition, the incorporation of tissue-specific genes and stem cells into the nanostructures increased the stability and enhanced transfection efficiency of gene/drug to the posterior segment of the eye. This review discusses available drug delivery systems and combination therapies together with challenges associated with each approach. As the last step, we discuss the application of nanofibrous scaffolds for the implantation of RPE progenitor cells with the aim to enhance cell adhesion and support a functionally polarized RPE monolayer.

scholarly journals Role of amyloid β-peptide in the pathogenesis of age-related macular degeneration

2021 ◽  
Vol 6 (1) ◽  
pp. e000774
Author(s):  
Minwei Wang ◽  
Shiqi Su ◽  
Shaoyun Jiang ◽  
Xinghuai Sun ◽  
Jiantao Wang
Keyword(s):  
Mitochondrial Dysfunction ◽  
Macular Degeneration ◽  
Vision Loss ◽  
Cell Structure ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Amyloid Β ◽  
Age Related Macular Degeneration ◽  
Amyloid Β Peptide ◽  
Age Related

Age-related macular degeneration (AMD) is the most common eye disease in elderly patients, which could lead to irreversible vision loss and blindness. Increasing evidence indicates that amyloid β-peptide (Aβ) might be associated with the pathogenesis of AMD. In this review, we would like to summarise the current findings in this field. The literature search was done from 1995 to Feb, 2021 with following keywords, ‘Amyloid β-peptide and age-related macular degeneration’, ‘Inflammation and age-related macular degeneration’, ‘Angiogenesis and age-related macular degeneration’, ‘Actin cytoskeleton and amyloid β-peptide’, ‘Mitochondrial dysfunction and amyloid β-peptide’, ‘Ribosomal dysregulation and amyloid β-peptide’ using search engines Pubmed, Google Scholar and Web of Science. Aβ congregates in subretinal drusen of patients with AMD and participates in the pathogenesis of AMD through enhancing inflammatory activity, inducing mitochondrial dysfunction, altering ribosomal function, regulating the lysosomal pathway, affecting RNA splicing, modulating angiogenesis and modifying cell structure in AMD. The methods targeting Aβ are shown to inhibit inflammatory signalling pathway and restore the function of retinal pigment epithelium cells and photoreceptor cells in the subretinal region. Targeting Aβ may provide a novel therapeutic strategy for AMD.

scholarly journals 4-(Phenylsulfanyl) Butan-2-One Attenuates the Inflammatory Response Induced by Amyloid-β Oligomers in Retinal Pigment Epithelium Cells

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Peeraporn Varinthra ◽  
Shun-Ping Huang ◽  
Supin Chompoopong ◽  
Zhi-Hong Wen ◽  
Ingrid Y. Liu
Keyword(s):  
Retinal Pigment Epithelium ◽  
Inflammatory Response ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Amyloid Β ◽  
Age Related Macular Degeneration ◽  
Epithelial Cell Line ◽  
Age Related ◽  
Tnf Α ◽  
Cox 2

Age-related macular degeneration (AMD) is a progressive eye disease that causes irreversible impairment of central vision, and effective treatment is not yet available. Extracellular accumulation of amyloid-beta (Aβ) in drusen that lie under the retinal pigment epithelium (RPE) has been reported as one of the early signs of AMD and was found in more than 60% of Alzheimer’s disease (AD) patients. Extracellular deposition of Aβ can induce the expression of inflammatory cytokines such as IL-1β, TNF-α, COX-2, and iNOS in RPE cells. Thus, finding a compound that can effectively reduce the inflammatory response may help the treatment of AMD. In this research, we investigated the anti-inflammatory effect of the coral-derived compound 4-(phenylsulfanyl) butan-2-one (4-PSB-2) on Aβ1-42 oligomer (oAβ1-42) added to the human adult retinal pigment epithelial cell line (ARPE-19). Our results demonstrated that 4-PSB-2 can decrease the elevated expressions of TNF-α, COX-2, and iNOS via NF-κB signaling in ARPE-19 cells treated with oAβ1-42 without causing any cytotoxicity or notable side effects. This study suggests that 4-PSB-2 is a promising drug candidate for attenuation of AMD.

scholarly journals A Splice Variant in SLC16A8 Gene Leads to Lactate Transport Deficit in Human iPS Cell-Derived Retinal Pigment Epithelial Cells

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 179
Author(s):  
Laurence Klipfel ◽  
Marie Cordonnier ◽  
Léa Thiébault ◽  
Emmanuelle Clérin ◽  
Frédéric Blond ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelial Cells ◽  
Age Related Macular Degeneration ◽  
Lactate Transport ◽  
Ips Cell ◽  
Risk Alleles ◽  
Age Related ◽  
A Genome

Age-related macular degeneration (AMD) is a blinding disease for which most of the patients remain untreatable. Since the disease affects the macula at the center of the retina, a structure specific to the primate lineage, rodent models to study the pathophysiology of AMD and to develop therapies are very limited. Consequently, our understanding relies mostly on genetic studies highlighting risk alleles at many loci. We are studying the possible implication of a metabolic imbalance associated with risk alleles within the SLC16A8 gene that encodes for a retinal pigment epithelium (RPE)-specific lactate transporter MCT3 and its consequences for vision. As a first approach, we report here the deficit in transepithelial lactate transport of a rare SLC16A8 allele identified during a genome-wide association study. We produced induced pluripotent stem cells (iPSCs) from the unique patient in our cohort that carries two copies of this allele. After in vitro differentiation of the iPSCs into RPE cells and their characterization, we demonstrate that the rare allele results in the retention of intron 2 of the SLC16A8 gene leading to the absence of MCT3 protein. We show using a biochemical assay that these cells have a deficit in transepithelial lactate transport.

scholarly journals Retinal Pigment Epithelium Expressed Toll-like Receptors and Their Potential Role in Age-Related Macular Degeneration

2021 ◽  
Vol 22 (16) ◽  
pp. 8387
Author(s):  
Alexa Klettner ◽  
Johann Roider
Keyword(s):  
Retinal Pigment Epithelium ◽  
Inflammatory Response ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Current Status ◽  
Toll Like Receptors ◽  
Cell Degeneration ◽  
Age Related

(1) Background: Inflammation is a major pathomechanism in the development and progression of age-related macular degeneration (AMD). The retinal pigment epithelium (RPE) may contribute to retinal inflammation via activation of its Toll-like receptors (TLR). TLR are pattern recognition receptors that detect the pathogen- or danger-associated molecular pattern. The involvement of TLR activation in AMD is so far not understood. (2) Methods: We performed a systematic literature research, consulting the National Library of Medicine (PubMed). (3) Results: We identified 106 studies, of which 54 were included in this review. Based on these studies, the current status of TLR in AMD, the effects of TLR in RPE activation and of the interaction of TLR activated RPE with monocytic cells are given, and the potential of TLR activation in RPE as part of the AMD development is discussed. (4) Conclusion: The activation of TLR2, -3, and -4 induces a profound pro-inflammatory response in the RPE that may contribute to (long-term) inflammation by induction of pro-inflammatory cytokines, reducing RPE function and causing RPE cell degeneration, thereby potentially constantly providing new TLR ligands, which could perpetuate and, in the long run, exacerbate the inflammatory response, which may contribute to AMD development. Furthermore, the combined activation of RPE and microglia may exacerbate neurotoxic effects.

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

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Annamaria Tisi ◽  
Marco Feligioni ◽  
Maurizio Passacantando ◽  
Marco Ciancaglini ◽  
Rita Maccarone
Keyword(s):  
Oxidative Stress ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Blood Retinal Barrier ◽  
Functional Changes ◽  
Beneficial Effects ◽  
Age Related ◽  
The Impact

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.

Sign in / Sign up

Export Citation Format

Share Document