Review Article

Amniotic membrane as a novel treatment in age-related macular degeneration: a narrative review

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Abstract: Age-related macular degeneration (ARMD), one of the most common causes of blindness, should be considered more due to its exponential increase in the coming 20 years as a result of increasing the age of the population. Whereas more recent studies offered newer scaling systems for ARMD, traditionally it is classified as the early and late stages. The main injury in this disease occurred in retinal pigment epithelium (RPE) and the retina. RPE cells have a crucial role in hemostasis and supporting photoreceptors. In the early stages, damages to RPE are minimal and mainly no treatment is needed because most patients are asymptomatic. However, in the late stages, RPE impairment may lead to the invasion of choroidal vessels into the retina. Although anti-angiogenic agents can inhibit this abnormal growth of blood vessels, they cannot stop it completely, and finally, total loss of retinal cells may occur (geographical atrophy). Since this prevalent disease has not had any cure yet, the concept of substituting the RPE cells should be considered. Repairing the injury to central nervous system cells is almost impossible because the regenerative capacity of these cells is limited. Recently, the use of regenerative substitutes has been suggested to replace damaged tissues. Amniotic membrane (AM) has been raised as a suitable substitute for damaged RPE cells due to all of its unique properties: pluripotency, anti-angiogenic effect, and anti-inflammatory effect. Based on the few studies that have been published so far, it seems that the use of this membrane in the treatment of ARMD can be helpful, but more studies are needed.

Review Article

Novel treatments and genetics of age-related macular degeneration-a narrative review

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Abstract: Age-related macular degeneration (AMD) remains a leading cause of severe visual impairment in developing countries. Although dry-type AMD and geographic atrophy (GA) are progressive conditions with the associated decrease of visual functions, no well-established treatment regimen was proposed for the disease. Wet-type AMD is effectively treated with intravitreal anti-angiogenic agents, but frequent injections are a major issue for the affected patients. Recent advances in AMD genetics have provided new insights into the pathogenesis and novel therapeutic targets of AMD, but the benefits of using genetic testing and genotype-based risk models for AMD development and progression still lacks evidence. Novel AMD treatments aim to increase the interval among intravitreal injections through new therapeutic agents and modern delivery devices. Simultaneously, gene therapy for dry and wet AMD is widely studied. Although gene therapy possesses a major superiority over other novel treatments regarding a persistent cure of disease, many challenges exist in the way of its broad impact on the ocular health of AMD patients.

Review Article

Molecular structure, pharmacokinetics and clinical evidence of brolucizumab: a narrative review

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Abstract: Macular neovascularization (MNV) is the hallmark of neovascular age-related macular degeneration (nAMD), one of the leading causes of vision loss in the developed world. The current MNV standard of care including frequent intravitreal anti-vascular endothelial growth factor (VEGF) injections, although has revolutionized favorably the treatment, places a substantial burden on patients, caregivers, and physicians. Brolucizumab is a newly developed single-chain antibody fragment that inhibits activation of VEGF receptor 2 with in vitro affinity and potency comparable to commercially-available anti-VEGF agents. Its small molecular weight and its design allow for high solubility and retinal tissue penetration, and improve bynding affinity to the target. Also a high clearance rate leading to minimal systemic exposure was observed. Brolucizumab has shown similar gains in visual acuity compared with other anti-VEGF molecules but a higher and earlier resolution of nAMD related fluid, achieving sustained macular dryness with longer mantainance injection interval ranging from 8 to 12 weeks after monthly loading doses. Rare cases of ocular inflammation also including retinal vasculitis and retinal vascular occlusions referred to an immune-mediated reaction posed safety concerns on selected patients and mantainance treatment interval shorter than 8 weeks.The present review summarizes several key points including the molecular structure and pharmacokinetics, the preclinical and clinical evidence of brolucizumab administration evaluating its efficacy, tolerability, and safety, extended dosing regimens and other indications still under clinical investigation.

Review Article

Narrative review of risuteganib for the treatment of dry age-related macular degeneration (AMD)

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Abstract: Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. AMD most commonly affects older individuals and is characterized by irreversible degeneration of the retinal pigment epithelium and neurosensory retina. Currently, there are limited treatment options for dry AMD outside of lifestyle modification and nutrient supplementation. Risuteganib [Luminate (ALG-1001), Allegro Ophthalmics, CA, USA] is an intravitreally administered inhibitor of integrin heterodimers αVβ3, αVβ5, α5β1, and αMβ2. It is currently undergoing clinical trials for the treatment of dry AMD and diabetic macular edema (DME). Preclinical studies have shown that risuteganib has an effect on the pathways for angiogenesis, inflammation, and vascular permeability. Ongoing clinical trials have had promising results showing improvements in patient best corrected visual acuity (BCVA) and reduced central macular thickness measured by optical coherence tomography (OCT). There is a pressing need for treatments for dry AMD and while risuteganib appears to have a potential benefit for patients, more data are needed before one can truly evaluate its efficacy. This narrative review provides a concise summary of the most up to date data regarding the proposed mechanism of action of risuteganib in the treatment of nonexudative AMD and DME as well as the results from recent phase 1 and phase 2 clinical trials.

Review Article

Statins for age related macular degeneration: promising but unproven

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Abstract: Statins are used widely to treat hypercholesterolemia and atherosclerotic cardiovascular disease. They have inflammatory and immunomodulatory effects potentially useful for managing systemic autoimmune diseases such as rheumatoid arthritis, lupus erythematosus and multiple sclerosis. Statins also have anti-oxidative and large-vessel endothelial supportive properties that occur independent of their lipid-lowering effects. Additionally, statins can suppress macrophage and microglial activation responsible for initiating inflammatory cytokine release. More than forty percent of adults aged 65 years or older use statins in the United States and Australia, a prevalence that increases with age. The effects of statin usage on ophthalmic practice are probably underrecognized. Cardiovascular disease and age-related macular degeneration (AMD) share common risk factors, consistent with the “vascular model” of AMD pathogenesis that implicates impaired choroidal circulation in Bruch’s membrane lipoprotein accumulation. AMD has a complex multifactorial pathogenesis involving oxidative stress, choroidal vascular dysfunction, dysregulated complement-cascade-mediated inflammation and pro-inflammatory and pro-angiogenic growth factors. Many of these components are hypothetically amenable to the primary (cholesterol lowering) and secondary (anti-inflammatory, anti-oxidative, anti-vasculopathy) effects of statin use. Experimental studies have been promising, epidemiological trails have produced conflicting results and three prospective clinical trials have been inconclusive at demonstrating the value of statin therapy for delaying or preventing AMD. Cumulative evidence to date has failed to prove conclusively that statins are beneficial for preventing or treating AMD.

Review Article

A narrative review on the role of abicipar in age-related macular degeneration

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Abstract: In developed countries, age-related macular degeneration (AMD) is the main cause of visual impairment in the elderly. Though the etiology of AMD is still unclear, it has been well understood that vascular endothelial growth factor (VEGF) is involved in the development of aberrant vasculature that represents the neovascular AMD (nAMD). Hence, VEGF inhibition is a more effective way to control nAMD. Pegaptanib, ranibizumab, and aflibercept are three drugs approved by the US Food and Drug Administration (FDA) to treat nAMD. Bevacizumab (an anti-VEGF medication comparable to ranibizumab) is already widely used off label. Existing anti-VEGF medicines are made up of antibodies or pieces of antibodies. Synthetic designed ankyrin repeat proteins (DARPins) imitate antibodies introduced recently by evolutions in bioengineering technology. These agents are designed to have high specificity and affinity to a specific target, smaller molecular size, and better tissue penetration, making them more stable and longer-acting at less concentration. Abicipar pegol (Allergan, Dublin, Ireland) is a DARPin that interlocks all VEGF-A isoforms. It has a greater affinity for VEGF and a longer intraocular half-life than ranibizumab, making it a feasible anti-VEGF agent. This review describes the properties and efficacy of abicipar, the new anti-VEGF agent, in clinical practice, which aims to improve outcomes, safety, and treatment burden of nAMD.

Review Article
Review Article

Novel mitochondrial therapies for the treatment of age-related macular degeneration

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Abstract: The purpose of this article is to review current literature and data regarding treatment options for age-related macular degeneration (AMD) related to mitochondrial therapy. This article considers the presence of flavoprotein fluorescence as a potential biomarker to test the effectiveness of the treatments. We focus primarily on two major mitochondrial targets, nuclear factor erythroid 2-related factor (NFE2L2) and PGC-1α, that function in controlling the production and effects of reactive oxidative species (ROS) directly in the mitochondria. PU-91 is an FDA approved drug that directly targets and upregulates PGC-1α in AMD cybrid cell lines. Although neither NFE2L2 nor PGC1-α have yet been tested in clinical trials, their effects have been studied in rodent models and offer promising results. MTP-131, or elamipretide?, and metformin are two drugs in phase II clinical trials that focus on the treatment of advanced, non-exudative AMD. MTP-131 functions by associating with cardiolipin (CL) whereas metformin targets adenosine-monophosphate protein kinase (AMPK) in the mitochondria. The current results of their clinical trials are elucidated in this article. The molecular targets and drugs reviewed in this article show promising results in the treatment of AMD. These targets can be further pursued to improve and refine treatment practices of this diagnosis.

Case Report

A case of infectious endophthalmitis misdiagnosed as uveitis

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Abstract: Intraocular foreign body residue following ophthalmic surgery is rare but may cause severe postoperative occult inflammation. In some cases, small foreign bodies located in the anterior chamber angle may be missed by follow-up ultrasound biomicroscopy (UBM). We report the case of an elderly female whose right eye was injured by a nail and received corneal repair surgery in our hospital. Eleven days post-surgery, we found a mobile, short, translucent, rod-shaped foreign body in the upper corner of the right eye and another in the iris root at 7 o’clock. Two months post-surgery, the patient consulted a doctor due to right eye redness, pain, and vision loss, which was ultimately shown to be associated with foreign body residue resulting in a delayed postoperative inflammatory response. The patient was cured by surgeries and active anti-inflammatory and anti-infection treatments, but the final diagnosis of the patient was infectious endophthalmitis misdiagnosed as uveitis, which worths our consideration. We also review relevant literature on the differentiation of postoperative infectious endophthalmitis from noninfectious uveitis. It’s a reminder that patients with delayed endophthalmitis after open ocular trauma should not exclude the possibility of intraocular foreign bodies. As well clinicians can distinguish infectious endophthalmitis from uveitis by needle aspiration biopsy or vitrectomy for microbial culture in order to determine the need for antibiotic treatment.

Review Article

Choriocapillaris in non-neovascular age-related macular degeneration as evaluated by optical coherence tomography angiography

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Abstract: Dramatic advances in retinal imaging technology over the last two decades have significantly improved our understanding of the natural history and pathophysiology of non-neovascular age-related macular degeneration (AMD). Currently, aside from micronutrient supplements, there are no proven treatments for non-neovascular or dry AMD. Recently, a number of pharmacological agents have been evaluated or are under evaluation for treatment of patients with end-stage dry AMD manifesting as geographic atrophy (GA). It may preferable, however, to intervene earlier in the disease before the development of irreversible loss of visual function. Earlier intervention would require a more precise understanding of biomarkers which may increase the risk of progression from early and intermediate stages to the late stage of the disease. The development of optical coherence tomography angiography (OCTA) has allowed the layers of the retinal microcirculation and choriocapillaris (CC) to be visualized and quantified. Flow deficits in the CC have been observed to increase with age, particularly centrally, and these flow deficits appear to worsen with development and progression of AMD. As such, OCTA-based CC assessment appears to be a valuable new biomarker in our assessment and risk-stratification of AMD. Alterations in the CC may also provide new insights into the pathophysiology of the disease. Enhancement of choriocapillaris function may also prove to be a target of future therapeutic strategies or as a biomarker to monitor the effectiveness of therapy. As such, CC imaging may be anticipated to be an integral tool in the management of dry AMD.

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    承办: 中山大学中山眼科中心
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  • Eye Science

    主管:中华人民共和国教育部
    主办: 中山大学
    承办: 中山大学中山眼科中心
    主编: 林浩添
    主管:中华人民共和国教育部
    主办: 中山大学
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