Protecting the aging eye with hydrogen sulfide

2020 ◽  
Author(s):  
Akash K George ◽  
Rubens Petit Homme ◽  
Dragana Stanisic ◽  
Suresh C. Tyagi ◽  
Mahavir Singh
Keyword(s):  
Hydrogen Sulfide ◽  
Ganglion Cells ◽  
Redox Homeostasis ◽  
Age Related Macular Degeneration ◽  
Glutamate Excitotoxicity ◽  
Blood Retinal Barrier ◽  
Functional Changes ◽  
Age Related ◽  
Oxygen Gradients ◽  
Vascular Occlusive Disease

Research demonstrates that senescence is associated with tissue and organ dysfunction, and the eye is no exception. Sequelae arising from aging have been well-defined as distinct clinical entities and vision-impairment has significant psychosocial consequences. Retina and adjacent tissues like retinal pigmented epithelium (RPE) and choroid are the key structures that are required for visual perception. Any structural and functional changes in retinal layers and blood retinal barrier (BRB) could lead to age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Further, there are significant oxygen gradients in eye that can lead to excessive reactive oxygen species (ROS) resulting in endoplasmic reticulum (ER) and mitochondrial stress response. These radicals are source of functional and morphological impairment in RPE, and retinal ganglion cells (RGCs). Therefore, ocular diseases could be summarized as disturbance in the redox homeostasis. Hyperhomocysteinemia (HHcy) is a risk factor and causes vascular occlusive disease of the retina. Interestingly, hydrogen sulfide (H2S) has been proven to be an effective antioxidant agent, and it can help treat diseases by alleviating stress and inflammation. Concurrent glutamate excitotoxicity, ER stress, and microglia activation are also linked to stress, thus H2S may offer additional interventional strategy. A refined understanding of the aging eye along with H2S biology, and pharmacology may help guide newer therapies for the eye

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.

Intraocular exosomes in eye diseases

2021 ◽  
Vol 21 ◽  
Author(s):  
Hui Zhang ◽  
Xiaomin Zhang ◽  
Xiaorong Li
Keyword(s):  
Messenger Rna ◽  
Biological Fluids ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Pathological State ◽  
Barrier Dysfunction ◽  
Blood Retinal Barrier ◽  
Ecm Remodeling ◽  
Age Related ◽  
Eye Tissues

: Exosomes, nanosized extracellular vesicles with a size of 30–150nm, contain many biological materials, such as messenger RNA (mRNA), microRNA (miRNA), proteins, and transcription factors. It has been identified in all biological fluids and recognized as an important part of intercellular communication. While the role of exosomes in cancer has been studied in-depth, our understanding of their relevance for ocular tissues has just begun to evolve. Intraocular fluids, including aqueous humor and vitreous humor, play a role in nourishing eye tissues and in expelling metabolites. In the pathological state, intraocular exosomes can mediate pathological processes such as ECM remodeling, retinal inflammation, and blood-retinal barrier dysfunction. Herein, we reviewed the latest advances of intraocular exosomes in the research of several eye diseases, including glaucoma, age-related macular degeneration, myopia, and ocular tumors, and discuss how intraocular exosomes contribute to the pathogenesis and progression of multiple eye diseases.

scholarly journals Neuroprotective Potential of Ginkgo biloba in Retinal Diseases

Planta Medica ◽  
2019 ◽  
Vol 85 (17) ◽  
pp. 1292-1303 ◽  
Author(s):  
Isabel Martínez-Solís ◽  
Nuria Acero ◽  
Francisco Bosch-Morell ◽  
Encarna Castillo ◽  
María Eugenia González-Rosende ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ginkgo Biloba ◽  
Redox Homeostasis ◽  
Antioxidant Properties ◽  
Retinal Disease ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Age Related ◽  
The Central Nervous System ◽  
Degenerative Processes

AbstractLike other tissues of the central nervous system, the retina is susceptible to damage by oxidative processes that result in several neurodegenerative disease such as age-related macular degeneration, diabetic retinopathy, glaucoma, ischaemic retinal disease, retinal disease produced by light oxidation, and detached retina, among other diseases. The use of antioxidant substances is a solution to some health problems caused by oxidative stress, because they regulate redox homeostasis and reduce oxidative stress. This is important for neurodegeneration linked to oxidation processes. In line with this, Ginkgo biloba is a medicinal plant with excellent antioxidant properties whose effects have been demonstrated in several degenerative processes, including retinal diseases associated with neurodegeneration. This review describes the current literature on the role of ginkgo in retinal diseases associated with neurodegeneration. The information leads to the conclusion that G. biloba extracts might be a good option to improve certain neurodegenerative retinal diseases, but more research is needed to determine the safety and efficacy of G. biloba in these retinal degenerative processes.

Anatomical and functional changes in neovascular AMD in remission: comparison of fibrocellular and fibrovascular phenotypes

2019 ◽  
Vol 104 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Lea Querques ◽  
Mariacristina Parravano ◽  
Enrico Borrelli ◽  
Adele Chiaravalloti ◽  
Massimiliano Tedeschi ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Fundus Autofluorescence ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Study Cohort ◽  
Neovascular Amd ◽  
Macular Function ◽  
Functional Changes ◽  
Age Related ◽  
Rpe Atrophy

PurposeTo investigate the anatomical changes and the macular function in neovascular age-related macular degeneration (AMD) eyes, according to the recognition of either fibrocellular or fibrovascular phenotype.MethodsWe enrolled eyes with previously treated neovascular AMD in remission (no subretinal haemorrhage, sign of fluid in or under the retina and no treatment for at least 6 months). Subjects underwent multimodal imaging assessment and were tested for macular sensitivity using microperimetry. The study cohort was divided according to the presence of fibrosis on multicolour (MC) images, yielding two distinct phenotypic subgroups: (1) fibrocellular group and (2) fibrovascular group.ResultsNineteen eyes were classified as fibrocellular on MC images, while 22 eyes as fibrovascular. Mean±SD age was 73.9±11.0 years in the fibrocellular group and 75.9±7.1 years in the fibrovascular group (p=0.221). Best-corrected visual acuity was 0.7±0.5 logarithm of the minimum angle of resolution (LogMAR) in the fibrocellular group and 0.3±0.2 LogMAR in the fibrovascular group (p=0.003). On the optical coherence tomography and fundus autofluorescence evaluation, 17/19 eyes with the fibrocellular phenotype and 8/22 eyes with the fibrovascular phenotype displayed the presence of retinal pigment epithelium (RPE) atrophy (p=0.001). The perfusion density within the neovascular lesion was 28.9%±9.9% in the fibrocellular group and 44.2%±5.9 % in the fibrovascular group (p<0.0001).ConclusionNeovascular AMD eyes in remission and with evidence of fibrocellular scar are characterised by RPE atrophy and reduced perfusion, which are associated with a higher degree of functional impairment. These findings suggest that maturation of vessels in fibrosis might be a better target in neovascular AMD treatments rather than their abolishment.

scholarly journals C-reactive protein isoforms differentially affect outer blood-retinal barrier integrity and function

2017 ◽  
Vol 312 (3) ◽  
pp. C244-C253 ◽  
Author(s):  
Blanca Molins ◽  
Anna Pascual ◽  
Méndez ◽  
Victor Llorenç ◽  
Javier Zarranz-Ventura ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Protein Isoforms ◽  
Age Related Macular Degeneration ◽  
C Reactive Protein ◽  
Barrier Dysfunction ◽  
Blood Retinal Barrier ◽  
Reactive Protein ◽  
Anti Vegf ◽  
Age Related

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier (oBRB) and is the prime target of early age-related macular degeneration (AMD). C-reactive protein (CRP), a serum biomarker for chronic inflammation and AMD, presents two different isoforms, monomeric (mCRP) and pentameric (pCRP), that may have a different effect on inflammation and barrier function in the RPE. The results reported in this study suggest that mCRP but not pCRP impairs RPE functionality by increasing paracellular permeability and disrupting the tight junction proteins ZO-1 and occludin in RPE cells. Additionally, we evaluated the effect of drugs commonly used in clinical settings on mCRP-induced barrier dysfunction. We found that a corticosteroid (methylprednisolone) and an anti-VEGF agent (bevacizumab) prevented mCRP-induced ARPE-19 barrier disruption and IL-8 production. Furthermore, bevacizumab was also able to revert mCRP-induced IL-8 increase after mCRP stimulation. In conclusion, the presence of mCRP within retinal tissue may lead to disruption of the oBRB, an effect that may be modified in the presence of corticosteroids or anti-VEGF drugs.

scholarly journals Oxidative stress-mediated TXNIP loss causes RPE dysfunction

2019 ◽  
Vol 51 (10) ◽  
pp. 1-13 ◽  
Author(s):  
Min Ji Cho ◽  
Sung-Jin Yoon ◽  
Wooil Kim ◽  
Jongjin Park ◽  
Jangwook Lee ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Common Factor ◽  
Age Related Macular Degeneration ◽  
Autophagic Flux ◽  
Blood Retinal Barrier ◽  
Rpe Cells ◽  
Age Related

Abstract The disruption of the retinal pigment epithelium (RPE), for example, through oxidative damage, is a common factor underlying age-related macular degeneration (AMD). Aberrant autophagy also contributes to AMD pathology, as autophagy maintains RPE homeostasis to ensure blood–retinal barrier (BRB) integrity and protect photoreceptors. Thioredoxin-interacting protein (TXNIP) promotes cellular oxidative stress by inhibiting thioredoxin reducing capacity and is in turn inversely regulated by reactive oxygen species levels; however, its role in oxidative stress-induced RPE cell dysfunction and the mechanistic link between TXNIP and autophagy are largely unknown. Here, we observed that TXNIP expression was rapidly downregulated in RPE cells under oxidative stress and that RPE cell proliferation was decreased. TXNIP knockdown demonstrated that the suppression of proliferation resulted from TXNIP depletion-induced autophagic flux, causing increased p53 activation via nuclear localization, which in turn enhanced AMPK phosphorylation and activation. Moreover, TXNIP downregulation further negatively impacted BRB integrity by disrupting RPE cell tight junctions and enhancing cell motility by phosphorylating, and thereby activating, Src kinase. Finally, we also revealed that TXNIP knockdown upregulated HIF-1α, leading to the enhanced secretion of VEGF from RPE cells and the stimulation of angiogenesis in cocultured human retinal microvascular endothelial cells. This suggests that the exposure of RPE cells to sustained oxidative stress may promote choroidal neovascularization, another AMD pathology. Together, these findings reveal three distinct mechanisms by which TXNIP downregulation disrupts RPE cell function and thereby exacerbates AMD pathogenesis. Accordingly, reinforcing or restoring BRB integrity by targeting TXNIP may serve as an effective therapeutic strategy for preventing or attenuating photoreceptor damage in AMD.

Scanning Laser Ophthalmoscope in the Management of Age-related Macular Degeneration

2012 ◽  
Vol 06 (04) ◽  
pp. 242
Author(s):  
Nicole K Scripsema ◽  
and Richard B Rosen ◽  
◽  
◽  
◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Fundus Autofluorescence ◽  
Disease Process ◽  
Scanning Laser Ophthalmoscope ◽  
Age Related Macular Degeneration ◽  
Scanning Laser ◽  
Functional Changes ◽  
Age Related ◽  
The Impact ◽  
Improved Methods

Recent advances in retinal imaging have improved the evaluation and prognostication of age-related macular degeneration. The development and modification of the scanning laser ophthalmoscope (SLO) has played a pivotal role in our understanding of the disease. SLO has led to improved methods of visualising characteristics of the disease, such as drusen and alterations in autofluorescence, and also provided a platform for the quantification of structural and functional changes occurring as a result of the disease process. This article provides a review of the current literature on the impact and clinical utility of SLO devices for infrared viewing, fundus autofluorescence, microperimetry, and as integraded multimodal imaging systems such as optical coherence tomography and SLO.

The Blood–Retinal Barrier in Retinal Disease

2009 ◽  
Vol 03 (02) ◽  
pp. 105 ◽  
Author(s):  
José Cunha-Vaz ◽  
Keyword(s):  
Diabetic Retinopathy ◽  
Tight Junctions ◽  
Retinal Pigment ◽  
Water Flux ◽  
Retinal Disease ◽  
Retinal Pigment Epithelial Cells ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Blood Retinal Barrier ◽  
Age Related

The blood–ocular barrier system is formed by two main barriers: the blood–aqueous barrier and the blood–retinal barrier (BRB). The BRB is particularly tight and restrictive and is a physiological barrier that regulates ion, protein and water flux into and out of the retina. The BRB consists of inner and outer components, the inner BRB being formed of tight junctions between retinal capillary endothelial cells and the outer BRB of tight junctions between retinal pigment epithelial cells. The BRB is essential to maintaining the eye as a privileged site and is essential for normal visual function. Alterations of the BRB play a crucial role in the development of retinal diseases. The two most frequent and relevant retinal diseases, diabetic retinopathy and age-related macular degeneration (AMD), are directly associated with alterations of the BRB. Diabetic retinopathy is initiated by an alteration of the inner BRB and neovascular AMD is a result of an alteration of the outer BRB. Treatment of retinal diseases must also deal with the BRB either by using its specific transport mechanisms or by circumventing it through intravitreal injections

Retinal Functional Changes Measured by Microperimetry in Neovascular Age-Related Macular Degeneration Treated With Ranibizumab

2013 ◽  
Vol 155 (1) ◽  
pp. 118-126.e1 ◽  
Author(s):  
Han Joo Cho ◽  
Chul Gu Kim ◽  
Su Jin Yoo ◽  
Sung Won Cho ◽  
Dong Won Lee ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Functional Changes ◽  
Age Related
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