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1.
Lutein and zeaxanthin attenuates VEGF-induced neovascularisation in human retinal microvascular endothelial cells through a Nox4-dependent pathway.
Keegan, G, Pardhan, S, Chichger, H
Experimental eye research. 2020;:108104
Abstract
Age-related macular degeneration (AMD) and proliferative diabetic retinopathy (DR) are two of the most common and severe causes of vision loss in the population. Both conditions are associated with excessive levels of vascular endothelial growth factor (VEGF) in the eye which results in an increase in the formation of new blood vessels through a process called neovascularisation. As such, anti-VEGF therapies are currently utilised as a treatment for patients with AMD however they are associated with painful administration of injections and potential degeneration of healthy endothelium. There is therefore growing interest in alternate treatment options to reduce neovascularisation in the eye. The use of carotenoids, lutein (L) and zeaxanthin (Z), has been shown to improve vision loss parameters in patients with AMD, however the underlying mechanisms are not well-understood. We studied the impact of these compounds on neovascularisation processes using an in vitro cell model of the retinal microvascular endothelium. Our findings show that L and Z reduced VEGF-induced tube formation whilst, in combination (5:1 ratio), the compounds significantly blocked VEGF-induced neovascularisation. The carotenoids, individually and in combination, reduced VEGF-induced oxidative stress concomitant with increased activity of the NADPH oxidase, Nox4. We further demonstrated that the Nox4 inhibitor, GLX7013114, attenuated the protective effect of L and Z. Taken together, these findings indicate the protective effect of the carotenoids, L and Z, in reducing VEGF-mediated neovascularisation via a Nox4-dependent pathway. These studies implicate the potential for these compounds to be used as a therapeutic approach for patients suffering from AMD and proliferative DR.
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2.
Targeting Angiopoietin in Retinal Vascular Diseases: A Literature Review and Summary of Clinical Trials Involving Faricimab.
Khan, M, Aziz, AA, Shafi, NA, Abbas, T, Khanani, AM
Cells. 2020;(8)
Abstract
This review summarizes the latest findings in the literature of Angiopoietin-2 (Ang-2), Tyrosine-protein kinase receptor (Tie-2) complex, and faricimab along with their involvement for the treatment of retinal vascular diseases in various clinical trials. In ischemic diseases, such as diabetic retinopathy, Ang-2 is upregulated, deactivating Tie-2, resulting in vascular leakage, pericyte loss, and inflammation. Recombinant Angiopeotin-1 (Ang-1), Ang-2-blocking molecules, and inhibitors of vascular endothelial protein tyrosine phosphatase (VE-PTP) decrease inflammation-associated vascular leakage, showing therapeutic effects in diabetes, atherosclerosis, and ocular neovascular diseases. In addition, novel studies show that angiopoietin-like proteins may play an important role in cellular metabolism leading to retinal vascular diseases. Current therapeutic focus combines Ang-Tie targeted drugs with other anti-angiogenic or immune therapies. Clinical studies have identified faricimab, a novel bispecific antibody designed for intravitreal use, to simultaneously bind and neutralize Ang-2 and VEGF-A for treatment of diabetic eye disease. By targeting both Ang-2 and vascular endothelial growth factor-A (VEGF-A), faricimab displays an improved and sustained efficacy over longer treatment intervals, delivering superior vision outcomes for patients with diabetic macular edema and reducing the treatment burden for patients with neovascular age-related macular degeneration and diabetic macular edema. Phase 2 results have produced promising outcomes with regard to efficacy and durability. Faricimab is currently being evaluated in global Phase 3 studies.
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3.
Diabetic Retinopathy and Vascular Endothelial Growth Factor Gene Insertion/Deletion Polymorphism.
Khan, SZ, Ajmal, N, Shaikh, R
Canadian journal of diabetes. 2020;(3):287-291
Abstract
Diabetic retinopathy (DR) is a microvascular complication of the retina of the eye and represents a major cause of blindness worldwide. It is a complex disorder characterized by both genetic and environmental factors. The vascular endothelial growth factor (VEGF) gene is among the main candidate genes for DR, as it is also involved in several other diseases, such as microvascular complications of diabetes mellitus and cancer. The VEGF gene is extremely polymorphic. The 18-bp fragment (insertion/deletion) polymorphism at the -2549 position of the promoter region of the VEGF gene is of great importance. In this review, we highlight the DR and VEGF gene (insertion/deletion) polymorphism. In addition, we assess this association in various DR populations and in other microvascular complications, such as diabetic nephropathy, diabetic peripheral neuropathy and cancer.
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Current concepts of pharmacotherapy of diabetic macular edema.
Haritoglou, C, Maier, M, Neubauer, AS, Augustin, AJ
Expert opinion on pharmacotherapy. 2020;(4):467-475
Abstract
Introduction: Diabetic macular edema (DME) is a sight threatening disease and a major cause for blindness for people in working age. The pathogenesis is multifactorial and complex. The pharmacotherapy of DME addresses both the inhibition of vascular endothelial growth factor (VEGF) by the intravitreal injection of VEGF inhibitors and inflammatory processes by the intravitreal application of steroids. Several trials have been published reporting on the efficacy and safety of these treatments.Areas covered: This review discusses original research articles including basic science and clinical studies as well as review articles focusing on the role of inflammation and VEGF expression in DME. It discusses newly published clinical trials on intravitreal pharmacotherapy for DME. The literature was searched using Medline/PubMed and was selected given its relevance for the topic to be discussed.Expert opinion: Our knowledge regarding the pathophysiology of diabetic macular edema has significantly increased. Some of these insights have been successfully transferred into current treatment strategies already including VEGF suppression or anti-inflammatory treatments using steroids. The identification of additional pathophysiological aspects and their relevance as potential treatment targets will be a future challenge in the treatment of DME. A better knowledge on the complex pathophysiology will also help to establish combination strategies.
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A literature analysis on anti-vascular endothelial growth factor therapy (anti-VEGF) using a bibliometric approach.
Yeung, AWK, Abdel-Daim, MM, Abushouk, AI, Kadonosono, K
Naunyn-Schmiedeberg's archives of pharmacology. 2019;(4):393-403
Abstract
We performed the current study to assess the citation performance of research works on anti-vascular endothelial growth factor (anti-VEGF) therapy. We searched Web of Science (WoS) to identify relevant publications and analyze them with reference to their publication year, journal title, citation count, WoS category, and article type. The bibliometric software (VOSviewer) was used for citation analyses of countries and journals and to generate a term map that visualizes the recurring terms appearing in the titles and abstracts of published articles. The literature search resulted in 7364 articles, with a mean citation count of 26.2. Over half of them (50.2%) were published during the past 5 years. Original articles constituted the majority (67.8%). The publications were mainly classified into WoS categories of ophthalmology (43.2%) and oncology (20.6%). The most prolific ophthalmology and cancer journals were Investigative Ophthalmology & Visual Science (7.3%) and Cancer Research (1.4%), respectively. The correlation between journal impact factor and citation count was weak to moderate (for journals with impact factor up to 5 and 10, respectively), and open-access articles had significantly more citations than non-open-access articles (p < 0.001). The frequently targeted tumors by anti-VEGF therapy included metastatic colorectal cancer (196; 49.2 citations per article (CPA)), breast cancers (167; 37.2 CPA), and renal cell carcinoma (122; 38.2 CPA). The frequently targeted eye pathologies were age-related macular degeneration (828; 18.2 CPA), diabetic macular edema (466; 10.8 CPA), and diabetic retinopathy (358; 31.9 CPA). These results indicate that anti-VEGF therapy has a wide range of applications and its publications are highly cited.
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6.
Dexamethasone and Anti-VEGF Combination Therapy for the Treatment of Diabetic Macular Edema.
Al-Khersan, H, Hariprasad, SM, Salehi-Had, H
Ophthalmic surgery, lasers & imaging retina. 2019;(1):4-7
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Comparison of efficacy between anti-vascular endothelial growth factor (VEGF) and laser treatment in Type-1 and threshold retinopathy of prematurity (ROP).
Li, Z, Zhang, Y, Liao, Y, Zeng, R, Zeng, P, Lan, Y
BMC ophthalmology. 2018;(1):19
Abstract
BACKGROUND Retinopathy of Prematurity (ROP) is one of the most common causes of childhood blindness worldwide. Comparisons of anti-VEGF and laser treatments in ROP are relatively lacking, and the data are scattered and limited. The objective of this meta-analysis is to compare the efficacy of both treatments in type-1 and threshold ROP. METHODS A comprehensive literature search on ROP treatment was conducted using PubMed and Embase up to March 2017 in all languages. Major evaluation indexes were extracted from the included studies by two authors. The fixed-effects and random-effects models were used to measure the pooled estimates. The test of heterogeneity was performed using the Q statistic. RESULTS Ten studies were included in this meta-analysis. Retreatment incidence was significantly increased for anti-VEGF (OR 2.52; 95% CI 1.37 to 4.66; P = 0.003) compared to the laser treatment, while the incidences of eye complications (OR 0.29; 95% CI 0.10 to 0.82; P = 0.02) and myopia were significantly decreased with anti-VEGF compared to the laser treatment. However, there was no difference in the recurrence incidence (OR 1.86; 95% CI 0.37 to 9.40; P = 0.45) and time between treatment and retreatment (WMD 7.54 weeks; 95% CI 2.00 to 17.08; P = 0.12). CONCLUSION This meta-analysis indicates that laser treatment may be more efficacious than anti-VEGF treatment. However, the results of this meta-analysis also suggest that laser treatment may cause more eye complications and increase myopia. Large-scale prospective RCTs should be performed to assess the efficacy and safety of anti-VEGF versus laser treatment in the future.
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8.
Evolving multidimensional pharmacological approaches to CNV therapy in AMD.
Ehrenberg, M, Benny, O
Current eye research. 2018;(2):147-154
Abstract
PURPOSE The leading cause of severe visual loss world-wide is age-related macular degeneration. Although anti-Vascular Endothelial Growth Factor agents have significantly led to the initial pharmacologic reversal of vision loss in many cases of exudative macular degeneration, there still has been recurrence of choroidal neovascularization, and/or the onset of chorioretinal atrophy with fibrosis. MATERIALS AND METHODS In this review we discuss the status of anti- Vascular Endothelial Growth Factor in age-related macular degeneration and describe different studies focused on new potential therapeutic targets beyond anti- Vascular Endothelial Growth Factor. RESULTS Further investigations have elicited that Vascular Endothelial Growth Factor is only one of many angiogenic, and pro-inflammatory factors that bring about the growth and leakage of active choroidal neovascularization. Various new multifaceted strategies, including inhibitors to down-stream targets of endothelial cell division, such as TNP-470, may lead to a more permanent inactivation of choroidal neovascularization. CONCLUSIONS Based on the accumulated results in the treatment of age-related macular degeneration, it is hoped that the appropriate combination of anti-Vascular Endothelial Growth Factor agents with longer-acting and multidimensional pharmaceuticals, such as Methionine Aminopeptidase-2 inhibitors, will more effectively control choroidal neovascularization, prevent atrophy and fibrosis, and reduce the burden of frequent intraocular injections in age-related macular degeneration.
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Management of VEGF-Targeted Therapy-Induced Hypertension.
Caletti, S, Paini, A, Coschignano, MA, De Ciuceis, C, Nardin, M, Zulli, R, Muiesan, ML, Salvetti, M, Rizzoni, D
Current hypertension reports. 2018;(8):68
Abstract
PURPOSE OF REVIEW From a physiological point of view, VEGFs (vascular endothelial growth factors) and their receptors (VEGFR) play a critical role in vascular development angiogenesis, endothelial function, and vascular tone. On the pathological side, VEGF-VEGFR signaling may induce dysregulated angiogenesis, which contributes to the growth and to the spread of tumors, being essential for neoplastic proliferation and invasion. RECENT FINDINGS Pharmacological inhibition of VEGF-VEGFR is now a cornerstone in the treatment of many malignancies; however, treatment with VEGF inhibitors is commonly associated with an increase in blood pressure values. This side effect is strictly connected with the mechanism of action of these medications and might represent an index of therapy efficacy. The optimal management of this form of hypertension is, at present, not clear. Calcium channel blockers and renin-angiotensin system inhibitors probably represent the most appropriate classes of hypertensive dugs for the treatment of this condition; however, no conclusive data are presently available.
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10.
Anti-vascular endothelial growth factor combined with intravitreal steroids for diabetic macular oedema.
Mehta, H, Hennings, C, Gillies, MC, Nguyen, V, Campain, A, Fraser-Bell, S
The Cochrane database of systematic reviews. 2018;(4):CD011599
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Abstract
BACKGROUND The combination of steroid and anti-vascular endothelial growth factor (VEGF) intravitreal therapeutic agents could potentially have synergistic effects for treating diabetic macular oedema (DMO). On the one hand, if combined treatment is more effective than monotherapy, there would be significant implications for improving patient outcomes. Conversely, if there is no added benefit of combination therapy, then people could be potentially exposed to unnecessary local or systemic side effects. OBJECTIVES To assess the effects of intravitreal agents that block vascular endothelial growth factor activity (anti-VEGF agents) plus intravitreal steroids versus monotherapy with macular laser, intravitreal steroids or intravitreal anti-VEGF agents for managing DMO. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 1); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the ICTRP. The date of the search was 21 February 2018. SELECTION CRITERIA We included randomised controlled trials (RCTs) of intravitreal anti-VEGF combined with intravitreal steroids versus intravitreal anti-VEGF alone, intravitreal steroids alone or macular laser alone for managing DMO. We included people with DMO of all ages and both sexes. We also included trials where both eyes from one participant received different treatments. DATA COLLECTION AND ANALYSIS We used standard methodological procedures recommended by Cochrane.Two authors independently reviewed all the titles and abstracts identified from the electronic and manual searches against the inclusion criteria. Our primary outcome was change in best corrected visual acuity (BCVA) between baseline and one year. Secondary outcomes included change in central macular thickness (CMT), economic data and quality of life. We considered adverse effects including intraocular inflammation, raised intraocular pressure (IOP) and development of cataract. MAIN RESULTS There were eight RCTs (703 participants, 817 eyes) that met our inclusion criteria with only three studies reporting outcomes at one year. The studies took place in Iran (3), USA (2), Brazil (1), Czech Republic (1) and South Korea (1). Seven studies used the unlicensed anti-VEGF agent bevacizumab and one study used licensed ranibizumab. The study that used licensed ranibizumab had a unique design compared with the other studies in that included eyes had persisting DMO after anti-VEGF monotherapy and received three monthly doses of ranibizumab prior to allocation. The anti-VEGF agent was combined with intravitreal triamcinolone in six studies and with an intravitreal dexamethasone implant in two studies. The comparator group was anti-VEGF alone in all studies; two studies had an additional steroid monotherapy arm, another study had an additional macular laser photocoagulation arm. Whilst we judged these studies to be at low risk of bias for most domains, at least one domain was at unclear risk in all studies.When comparing anti-VEGF/steroid with anti-VEGF monotherapy as primary therapy for DMO, we found no meaningful clinical difference in change in BCVA (mean difference (MD) -2.29 visual acuity (VA) letters, 95% confidence interval (CI) -6.03 to 1.45; 3 RCTs; 188 eyes; low-certainty evidence) or change in CMT (MD 0.20 μm, 95% CI -37.14 to 37.53; 3 RCTs; 188 eyes; low-certainty evidence) at one year. There was very low-certainty evidence on intraocular inflammation from 8 studies, with one event in the anti-VEGF/steroid group (313 eyes) and two events in the anti-VEGF group (322 eyes). There was a greater risk of raised IOP (Peto odds ratio (OR) 8.13, 95% CI 4.67 to 14.16; 635 eyes; 8 RCTs; moderate-certainty evidence) and development of cataract (Peto OR 7.49, 95% CI 2.87 to 19.60; 635 eyes; 8 RCTs; moderate-certainty evidence) in eyes receiving anti-VEGF/steroid compared with anti-VEGF monotherapy. There was low-certainty evidence from one study of an increased risk of systemic adverse events in the anti-VEGF/steroid group compared with the anti-VEGF alone group (Peto OR 1.32, 95% CI 0.61 to 2.86; 103 eyes).One study compared anti-VEGF/steroid versus macular laser therapy. At one year investigators did not report a meaningful difference between the groups in change in BCVA (MD 4.00 VA letters 95% CI -2.70 to 10.70; 80 eyes; low-certainty evidence) or change in CMT (MD -16.00 μm, 95% CI -68.93 to 36.93; 80 eyes; low-certainty evidence). There was very low-certainty evidence suggesting an increased risk of cataract in the anti-VEGF/steroid group compared with the macular laser group (Peto OR 4.58, 95% 0.99 to 21.10, 100 eyes) and an increased risk of elevated IOP in the anti-VEGF/steroid group compared with the macular laser group (Peto OR 9.49, 95% CI 2.86 to 31.51; 100 eyes).One study provided very low-certainty evidence comparing anti-VEGF/steroid versus steroid monotherapy at one year. There was no evidence of a meaningful difference in BCVA between treatments at one year (MD 0 VA letters, 95% CI -6.1 to 6.1, low-certainty evidence). Likewise, there was no meaningful difference in the mean CMT at one year (MD - 9 μm, 95% CI -39.87μm to 21.87μm between the anti-VEGF/steroid group and the steroid group. There was very low-certainty evidence on raised IOP at one year comparing the anti-VEGF/steroid versus steroid groups (Peto OR 0.75, 95% CI 0.16 to 3.55).No included study reported impact of treatment on patients' quality of life or economic data. None of the studies reported any cases of endophthalmitis. AUTHORS' CONCLUSIONS Combination of intravitreal anti-VEGF plus intravitreal steroids does not appear to offer additional visual benefit compared with monotherapy for DMO; at present the evidence for this is of low-certainty. There was an increased rate of cataract development and raised intraocular pressure in eyes treated with anti-VEGF plus steroid versus anti-VEGF alone. Patients were exposed to potential side effects of both these agents without reported additional benefit. The majority of the evidence comes from studies of bevacizumab and triamcinolone used as primary therapy for DMO. There is limited evidence from studies using licensed intravitreal anti-VEGF agents plus licensed intravitreal steroid implants with at least one year follow-up. It is not known whether treatment response is different in eyes that are phakic and pseudophakic at baseline.