Adverse events and complications associated with intravitreal injection of anti-VEGF agents: a review of literature

Suppression of retinal neovascularization by intravitreal injection of cryptotanshinone

Neovascular eye diseases, including proliferative diabetic retinopathy and retinopathy of prematurity, is a major cause of blindness. Laser ablation and intravitreal anti-VEGF injection have shown their limitations in treatment of retinal neovascularization. Identification of a new therapeutic strategies is in urgent need. Our study aims to assess the effects of Cryptotanshinone (CPT), a natural compound derived from Salvia miltiorrhiza Bunge, in retina neovascularization and explore its potential mechanism. Our study demonstrated that CPT did not cause retina tissue toxicity at the tested concentrations. Intravitreal injections of CPT reduced pathological angiogenesis and promoted physical angiogenesis in oxygen-induced retinopathy (OIR) model. CPT improve visual function in OIR mice and reduced cell apoptosis. Moreover, we also revealed that CPT diminishes the expression of inflammatory cytokines in the OIR retina. In vitro, the administration of CPT effectively inhibited endothelial cells proliferation, migration, sprouting, and tube formation induced by the stimulation of human retinal vascular endothelial cells (HRVECs) with VEGF165. Mechanistically, CPT blocking the phosphorylation of VEGFR2 and downstream targeting pathway. After all, the findings demonstrated that CPT exhibits potent anti-angiogenic and anti-inflammatory effects in OIR mice, and it has therapeutic potential for the treatment of neovascular retinal diseases.

Oxidative and carbonyl stress induced AMD and Codonopsis lanceolata ameliorates AMD via controlling oxidative and carbonyl stress

Age-related macular degeneration (AMD) is one of the leading causes of blindness. AMD is currently incurable; the best solution is to prevent its occurrence. To develop drugs for AMD, it is crucial to have a model system that mimics the symptoms and mechanisms in patients. It is most important to develop safer and more effective anti-AMD drug. In this study, the dose of A2E and the intensity of blue light were evaluated to establish an appropriate atrophic in vitro model of AMD and anti-AMD effect and therapeutic mechanism of Codonopsis lanceolata. The experimental groups included a control group an AMD group treated with A2E and blue light, a lutein group treated with 25 μM lutein after AMD induction, and three groups treated with different doses of C. lanceolata (10, 20, and 50 μg/mL) after AMD induction. Intrinsic apoptotic pathway (Bcl-2 family), anti-oxidative system (Keap1/Nrf2/HO-1 antioxidant response element), and anti-carbonyl effect (4-hydroxynonenal [4-HNE]) were evaluated using immunofluorescence, MTT, TUNEL, FACS, and western blotting analyses. A2E accumulation in the cytoplasm of ARPE-19 cells depending on the dose of A2E. Cell viability of ARPE-19 cells according to the dose of A2E and/or blue light intensity. The population of apoptotic or necrotic cells increased based on the A2E dose and blue light intensity. Codonopsis lanceolata dose-dependently prevented cell death which was induced by A2E and blue light. The antiapoptotic effect of that was caused by activating Keap1/Nrf2/HO-1 pathway, suppressing 4-HNE, and modulating Bcl-2 family proteins like increase of antiapoptotic proteins such as Bcl-2 and Bcl-XL and decrease of proapoptotic protein such as Bim. Based on these findings, 30 μM A2E and 20 mW/cm2 blue light on adult retinal pigment epithelium-19 cells was an appropriate condition for AMD model and C. lanceolata shows promise as an anti-AMD agent.

Cardiovascular and cerebrovascular adverse events associated with intravitreal anti-vascular endothelial growth factor monoclonal antibodies: a World Health Organization pharmacovigilance study

PURPOSE

To analyze cardiovascular and cerebrovascular adverse events (ADRs) after intravitreal anti-vascular endothelial growth factor (VEGF; aflibercept, bevacizumab, brolucizumab, and ranibizumab) treatment.

SUBJECTS

VigiBase, a World Health Organization (WHO) global safety report database DESIGN: Pharmacovigilance study METHODS: The individual-case-safety reports (ICSR) of cardiovascular and cerebrovascular ADRs after intravitreal anti-VEGF treatment were compared with those reported in the full database. From 2004 to 2023, 23,129 ADRs after intravitreal anti-VEGF therapy and 25,015,132 ADRs associated with any drug (full database).

MAIN OUTCOME MEASURES

The reporting odds ratio (ROR) and information components (IC) were calculated, and the 95% lower credibility interval endpoint of the information component (IC025) was used for disproportionate Bayesian reporting. Inter-drug comparisons were performed using the ratio of odd ratio (rOR).

RESULTS

Compared with the full database, anti-VEGFs were associated with an increased reporting of myocardial infarction (IC025 0.75; ROR: 1.78 [95% CI 1.70-1.86]), angina pectoris (IC025 0.53; ROR: 1.61 [95% CI 1.47-1.77]), arrythemias including atrial fibrillation, atrial flutter, ventricular fibrillation, supraventricular tachycardia (all IC025 >0, ROR>1), hypertension (IC025 2.22; ROR: 4.91 [95% CI 4.82-5.01]), and hypertensive crisis (IC025 1.97; ROR: 4.49 [95% CI 4.07-4.97]). Moreover, anti-VEGFs were associated with a higher reporting of cerebrovascular ADRs such as cerebral infarction (IC025 4.34; ROR: 23.19 [95% CI 22.10-24.34]), carotid artery stenosis (IC025 1.85; ROR: 5.24 [95% CI 3.98-6.89]), cerebral hemorrhage (IC025 2.29; ROR: 5.38 [95% CI 5.03-5.76]), and subarachnoid hemorrhage (IC025 1.98; ROR: 4.81 [95% CI 4.14-5.6]). Inter-drug comparison indicated that compared to ranibizumab, patients with aflibercept showed overall under-reporting of cardiovascular and cerebrovascular ADRs such as myocardial infarction (rOR 0.55 [95% CI 0.49-0.52]), atrial fibrillation (rOR 0.28 [95% CI 0.23-0.35]), cerebrovascular accident (rOR, 0.15 [95% CI 0.14-0.17]), and cerebral hemorrhage (rOR, 0.51 [95% CI 0.40-0.65]).

CONCLUSIONS

In this pharmacovigilance case-noncase study, significantly increased reporting of cardiovascular and cerebrovascular ADRs were identified after intravitreal anti-VEGF treatment. While ranibizumab may exhibit superior systemic safety regarding its biological characteristics, it is crucial not to overlook the occurrence of cardiovascular and cerebrovascular ADRs considering its higher reporting rate than bevacizumab or aflibercept.

Factors affecting prognosis and need for anti-vascular endothelial growth factor injections in wet age-related macular degeneration

PURPOSE

To understand factors affecting visual prognosis and the number of intravitreal antivascular endothelial growth factor (anti-VEGF) injections needed to stabilize wet age-related macular degeneration (AMD).

METHODS

In this retrospective cohort, 119 treatment-naïve wet AMD patients were followed for two years. In patients with bilateral disease, the eye with worse best-corrected visual acuity (BCVA) or that received more intravitreal injections was recruited as the study eye. In all visits, BCVA was recorded, ophthalmological examination was performed including macular optical coherence tomography imaging. Twenty health status/lifestyle questions were asked to the patients via phone as potential risk factors. All patients received 3 loading doses of intravitreal bevacizumab injections and received repeat injections of aflibercept or ranibizumab when the eye had a new, active neovascular lesion.

RESULTS

Patients who took regular micronutrition had similar visual outcome and injection numbers compared to the ones who did not. Patients with bilateral disease needed less intravitreal injections compared to unilateral AMD patients (p = 0.016) and women on hormone replacement therapy (HRT) required less injections compared to the women who were not (p = 0.024). Female patients had a mean gain of 2.7 letters while male patients lost 3.8 letters (p = 0.038). Wet AMD started at an earlier age in smokers (p = 0.002). Patients with a better education level presented earlier with better BCVA (p = 0.037).

CONCLUSION

HRT and anti-VEGF injections to the fellow eye improved the prognosis of wet AMD, while male patients had slightly worse prognosis. Estrogen's protective effects and potential contribution in wet AMD needs further attention. Retrospectively registered: 2020/0622.

Intravitreal therapeutic nanoparticles for age-related macular degeneration: Design principles, progress and opportunities

Age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly. The current standard treatment for AMD involves frequent intravitreal administrations of therapeutic agents. While effective, this approach presents challenges, including patient discomfort, inconvenience, and the risk of adverse complications. Nanoparticle-based intravitreal drug delivery platforms offer a promising solution to overcome these limitations. These platforms are engineered to target the retina specifically and control drug release, which enhances drug retention, improves drug concentration and bioavailability at the retinal site, and reduces the frequency of injections. This review aims to uncover the design principles guiding the development of highly effective nanoparticle-based intravitreal drug delivery platforms for AMD treatment. By gaining a deeper understanding of the physiology of ocular barriers and the physicochemical properties of nanoparticles, we establish a basis for designing intravitreal nanoparticles to optimize drug delivery and drug retention in the retina. Furthermore, we review recent nanoparticle-based intravitreal therapeutic strategies to highlight their potential in improving AMD treatment efficiency. Lastly, we address the challenges and opportunities in this field, providing insights into the future of nanoparticle-based drug delivery to improve therapeutic outcomes for AMD patients.

Role of death-associated protein kinase 1 (DAPK1) in retinal degenerative diseases: an in-silico approach towards therapeutic intervention

The Death-associated protein kinase 1 (DAPK1) has emerged as a crucial player in the pathogenesis of degenerative diseases. As a serine/threonine kinase family member, DAPK1 regulates critical signaling pathways, such as apoptosis and autophagy. In this study, we comprehensively analyzed DAPK1 interactors and enriched molecular functions, biological processes, phenotypic expression, disease associations, and aging signatures to elucidate the molecular networks of DAPK1. Furthermore, we employed a structure-based virtual screening approach using the PubChem database, which enabled the identification of potential bioactive compounds capable of inhibiting DAPK1, including caspase inhibitors and synthetic analogs. Three selected compounds, CID24602687, CID8843795, and CID110869998, exhibited high docking affinity and selectivity towards DAPK1, which were further investigated using molecular dynamics simulations to understand their binding patterns. Our findings establish a connection between DAPK1 and retinal degenerative diseases and highlight the potential of these selected compounds for the development of novel therapeutic strategies. This study provides valuable insights into the molecular mechanisms underlying DAPK1-related diseases, and offers new opportunities for the discovery of effective treatments for retinal degeneration.Communicated by Ramaswamy H. Sarma.

Efficient retinal ganglion cells transduction by retro-orbital venous sinus injection of AAV-PHP.eB in mature mice

Gene therapy is one of the strategies that may reduce or reverse progressive neurodegeneration in retinal neurodegenerative diseases. However, efficiently delivering transgenes to retinal ganglion cells (RGCs) remains hard to achieve. In this study, we innovatively investigated transduction efficiency of adeno-associated virus (AAV)-PHP.eB in murine RGCs by retro-orbital venous sinus injection. Five doses of AAV-PHP.eB-EGFP were retro-orbitally injected in venous sinus in adult C57/BL6J mice. Two weeks after administration, RGCs transduction efficiency was quantified by retinal flat-mounts and frozen section co-labeling with RGCs marker Rbpms. In addition, safety of this method was evaluated by RGCs survival rate and retinal morphology. To conform efficacy of this new method, AAV-PHP.eB-CNTF was administrated into mature mice through single retro-orbital venous injection after optic nerve crush injury to evaluate axonal elongation. Results indicated that AAV- PHP.eB readily crossed the blood-retina barrier and was able to transduce more than 90% of RGCs when total dose of virus reached 5 × 1010 vector genomes (vg). Moreover, this technique did not affect RGCs survival rate and retinal morphology. Furthermore, retro-orbital venous delivery of AAV-PHP.eB-CNTF effectively transduced RGCs, robustly promoted axonal regeneration after optic nerve crush injury. Thus, novel AAV-PHP.eB retro-orbital injection provides a minimally invasive and efficient route for transgene delivery in treatment of retinal neurodegenerative diseases.

Potential therapeutic effects of peroxisome proliferator-activated receptors on corneal diseases

The cornea is an avascular tissue in the eye that has multiple functions in the eye to maintain clear vision which can significantly impair one's vision when subjected to damage. Peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptor proteins comprising three different peroxisome proliferator-activated receptor (PPAR) isoforms, namely, PPAR alpha (α), PPAR gamma (γ), and PPAR delta (δ), have emerged as potential therapeutic targets for treating corneal diseases. In this review, we summarised the current literature on the therapeutic effects of PPAR agents on corneal diseases. We discussed the role of PPARs in the modulation of corneal wound healing, suppression of corneal inflammation, neovascularisation, fibrosis, stimulation of corneal nerve regeneration, and amelioration of dry eye by inhibiting oxidative stress within the cornea. We also discussed the underlying mechanisms of these therapeutic effects. Future clinical trials are warranted to further attest to the clinical therapeutic efficacy.

Oleogels: Versatile Novel Semi-Solid System for Pharmaceuticals

Oleogels is a novel semi-solid system, focusing on its composition, formulation, characterization, and diverse pharmaceutical applications. Due to their stability, smoothness, and controlled release qualities, oleogels are frequently utilized in food, cosmetics, and medicinal products. Oleogels are meticulously formulated by combining oleogelators like waxes, fatty acids, ethyl cellulose, and phytosterols with edible oils, leading to a nuanced understanding of their impact on rheological characteristics. They can be characterized by methods like visual inspection, texture analysis, rheological measurements, gelation tests, and microscopy. The applications of oleogels are explored in diverse fields such as nutraceuticals, cosmetics, food, lubricants, and pharmaceutics. Oleogels have applications in topical, transdermal, and ocular drug delivery, showcasing their potential for revolutionizing drug administration. This review aims to enhance the understanding of oleogels, contributing to the evolving landscape of pharmaceutical formulations. Oleogels emerge as a versatile and promising solution, offering substantial potential for innovation in drug delivery and formulation practices.

Multifunctional nano-in-micro delivery systems for targeted therapy in fundus neovascularization diseases

Fundus neovascularization diseases are a series of blinding eye diseases that seriously impair vision worldwide. Currently, the means of treating these diseases in clinical practice are continuously evolving and have rapidly revolutionized treatment opinions. However, key issues such as inadequate treatment effectiveness, high rates of recurrence, and poor patient compliance still need to be urgently addressed. Multifunctional nanomedicine can specifically respond to both endogenous and exogenous microenvironments, effectively deliver drugs to specific targets and participate in activities such as biological imaging and the detection of small molecules. Nano-in-micro (NIM) delivery systems such as metal, metal oxide and up-conversion nanoparticles (NPs), quantum dots, and carbon materials, have shown certain advantages in overcoming the presence of physiological barriers within the eyeball and are widely used in the treatment of ophthalmic diseases. Few studies, however, have evaluated the efficacy of NIM delivery systems in treating fundus neovascular diseases (FNDs). The present study describes the main clinical treatment strategies and the adverse events associated with the treatment of FNDs with NIM delivery systems and summarizes the anatomical obstacles that must be overcome. In this review, we wish to highlight the principle of intraocular microenvironment normalization, aiming to provide a more rational approach for designing new NIM delivery systems to treat specific FNDs.

Urolithin A promotes p62-dependent lysophagy to prevent acute retinal neurodegeneration

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of blindness in elderly people in the developed world, and the number of people affected is expected to almost double by 2040. The retina presents one of the highest metabolic demands in our bodies that is partially or fully fulfilled by mitochondria in the neuroretina and retinal pigment epithelium (RPE), respectively. Together with its post-mitotic status and constant photooxidative damage from incoming light, the retina requires a tightly-regulated housekeeping system that involves autophagy. The natural polyphenol Urolithin A (UA) has shown neuroprotective benefits in several models of aging and age-associated disorders, mostly attributed to its ability to induce mitophagy and mitochondrial biogenesis. Sodium iodate (SI) administration recapitulates the late stages of AMD, including geographic atrophy and photoreceptor cell death.

METHODS

A combination of in vitro, ex vivo and in vivo models were used to test the neuroprotective potential of UA in the SI model. Functional assays (OCT, ERGs), cellular analysis (flow cytometry, qPCR) and fine confocal microscopy (immunohistochemistry, tandem selective autophagy reporters) helped address this question.

RESULTS

UA alleviated neurodegeneration and preserved visual function in SI-treated mice. Simultaneously, we observed severe proteostasis defects upon SI damage induction, including autophagosome accumulation, that were resolved in animals that received UA. Treatment with UA restored autophagic flux and triggered PINK1/Parkin-dependent mitophagy, as previously reported in the literature. Autophagy blockage caused by SI was caused by severe lysosomal membrane permeabilization. While UA did not induce lysosomal biogenesis, it did restore upcycling of permeabilized lysosomes through lysophagy. Knockdown of the lysophagy adaptor SQSTM1/p62 abrogated viability rescue by UA in SI-treated cells, exacerbated lysosomal defects and inhibited lysophagy.

CONCLUSIONS

Collectively, these data highlight a novel putative application of UA in the treatment of AMD whereby it bypasses lysosomal defects by promoting p62-dependent lysophagy to sustain proteostasis.

Potential Risk Factors for Ocular Pain in Patients Undergoing Multiple Intravitreal Injections of Anti-Vascular Endothelial Growth Factor

Purpose

To assess ocular pain in patients undergoing multiple intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) who have previous factors that may influence pain sensitivity.

Methodology

This is a prospective, observational, case series study involving patients who underwent multiple (≥3) pro re nata intravitreal injections of ranibizumab or aflibercept to treat any cause of chorioretinal vascular disease. Ocular pain was assessed by the numerical analog scale during intravitreal injection. For this study, the main variable was ocular pain and the secondary variables included age, sex, previous history of glaucoma, primary retinal vascular disease, severe dry eye history, trigeminal pain, scleral buckle surgery, collagen diseases, fibromyalgia, severe migraine history, pars plana vitrectomy, scleral thickness measurements, and type of anti-VEGF.

Results

In a total of 894 patients, 948 eyes (4822 intravitreal injections), 793 patients (88.6%) had ocular pain sensitivity between no pain to mild pain, 80 patients (8.9%) had moderate ocular pain, 15 patients (1.6%) had severe ocular pain, and 6 patients (0.7%) had extremely severe ocular pain. Patients with severe dry eye (p = 0.01) and previous history of scleral buckle surgery (p = 0.01) showed a significant correlation with ocular pain during intravitreal injection. Pars plana scleral thickness (>550 um) and diabetic neuropathy were associated with ocular pain but did not meet the criteria for statistical significance (p = 0.09 and p = 0.06, respectively).

Conclusion

Dry eye and prior scleral buckle surgery may contribute to pain associated with intravitreal injection. These issues should be taken into consideration in patients undergoing multiple intravitreal injections.

Effect of twisting of intravitreal injections on ocular bio-mechanics: a novel insight to ocular surgery

Although intravitreal (IVT) injections provide several advantages in treating posterior segment eye diseases, several associated challenges remain. The current study uses the finite element method (FEM) to highlight the effect of IVT needle rotation along the insertion axis on the reaction forces and deformation inside the eye. A comparison of the reaction forces at the eye's key locations has been made with and without rotation. In addition, a sensitivity analysis of various parameters, such as the needle's angular speed, insertion location, angle, gauge, shape, and intraocular pressure (IOP), has been carried out to delineate the individual parameter's effect on reaction forces during rotation. Results demonstrate that twisting the needle significantly reduces the reaction forces at the penetration location and throughout the needle travel length, resulting in quicker penetration. Moreover, ocular biomechanics are influenced by needle insertion location, angle, shape, size, and IOP. The reaction forces incurred by the patient may be reduced by using a bevel needle of the higher gauge when inserted close to the normal of the local scleral surface toward the orra serrata within the Pars Plana region. Results obtained from the current study can deepen the understanding of the twisting needle's interaction with the ocular tissue.

Risk of Endophthalmitis Based on Cumulative Number of Anti-VEGF Intravitreal Injections

PURPOSE

To determine the risk of endophthalmitis in eyes undergoing intravitreal injections (IVIs) of anti-VEGF based on cumulative number of injections per eye.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients from a single center undergoing IVIs of ranibizumab, aflibercept, or bevacizumab.

METHODS

Eyes were divided into quartiles based on injection number causative of endophthalmitis between January 1, 2011, and June 1, 2022.

MAIN OUTCOME MEASURES

Interquartile clinical outcomes and cumulative risk of endophthalmitis per injection and per eye.

RESULTS

A total of 43 393 eyes received 652 421 anti-VEGF injections resulting in 231 endophthalmitis cases (0.035% per injection, 1 in 2857), of which 215 were included. The cumulative endophthalmitis risk increased from 0.0018% (1 in 55 556) after 1 injection to 0.013% (1 in 7692) after 11 injections (0.0012 percentage point change), versus 0.014% (1 in 7143) after 12 injections to 0.025% (1 in 4000) after 35 injections (0.00049 percentage point change), versus 0.025% (1 in 4000) after 36 injections to 0.031% (1 in 3226) after 66 injections (0.00017 percentage point change), versus 0.031% (1 in 3226) after 63 injections to 0.033% (1 in 3030) after 126 injections (0.000042 percentage point change) (P < 0.001). Likewise, the cumulative endophthalmitis risk per eye increased from 0.028% (1 in 3571) to 0.20% (1 in 500) between injections 1 and 11 (0.018 percentage point change), versus 0.21% (1 in 476) to 0.38% (1 in 263) between injections 12 and 35 (0.0075 percentage point change), versus 0.38% (1 in 263) to 0.46% (1 in 217) between injections 36 and 66 (0.0026 percentage point change), versus 0.46% (1 in 217) to 0.50% (1 in 200) between injections 67 and 126 (0.00063 percentage point change) (P < 0.001).

CONCLUSIONS

The cumulative endophthalmitis risk per injection and per eye increased with greater number of injections received but appeared to do so at a higher rate during earlier injections and at a lower rate further into the treatment course.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

The Reinforced Treat-and-Extend Protocol for Exudative Age-Related Macular Degeneration: Retrospective Assessment of 24-Month Real-World Outcomes in France

INTRODUCTION

The aim of this work is to evaluate the real-world outcomes of the reinforced treat-and-extend (RTE) protocol for the treatment of exudative age-related macular degeneration with intravitreal injections of aflibercept or ranibizumab (anti-vascular endothelial growth factor therapies).

METHODS

This was a retrospective review of patients from two tertiary ophthalmology centers in France initiating the RTE protocol between February 2018 and June 2021. The primary outcome was change in best-corrected visual acuity (BCVA) after 24 months. Secondary outcomes were change in central retinal thickness (CRT), recurrence, and management-related factors (injection interval, number of injections/consultations). Outcomes were additionally evaluated after protocol changes (strict versus modified RTE protocol groups).

RESULTS

Sixty-eight patients (72 eyes) were included (68% females; mean age 82.2 ± 7.8 years). After 24 months, mean BCVA significantly improved (65.22 ± 14 vs. 71.96 ± 13 Early Treatment Diabetic Retinopathy Study letters; p < 0.001) and CRT significantly decreased (388.6 ± 104 vs. 278.8 ± 51 μM; p < 0.001) with 21% of eyes showing signs of exudation. Over the 24 months, a mean total of 14.9 ± 4.0 injections and 8.6 ± 1.4 consultations were performed. Mean 24-month injection interval was 7.9 ± 2.3 weeks. Initial and 24-month ophthalmic outcomes for eyes in the strict (47%) versus modified (53%) groups were not significantly different, but mean time interval to first recurrence of disease activity was significantly shorter for the modified group (7.3 ± 2.4 vs. 9.9 ± 2.5 weeks; p < 0.001). Patients in the strict RTE group received significantly less injections (13.9 ± 3.6 vs. 16.5 ± 3.9; p = 0.006) and mean 24-month injection interval was significantly longer (9.5 ± 2.7 vs. 6.5 ± 2.1 weeks; p < 0.001). Consultation number was similar (8.5 ± 1.9 vs. 8.8 ± 1.6; p = 0.93). Treatment with aflibercept versus ranibizumab did not influence ophthalmic or management outcomes.

CONCLUSIONS

The RTE protocol, even when modified, reduced consultations but improved ophthalmic outcomes. The RTE protocol could reduce hospital visits and overall burden while also encouraging better patient compliance. Video Abstract available for this article.

VIDEO ABSTRACT

Vincent Soler and François-Philippe Roubelat summarize the Reinforced Treat-and-Extend Protocol and main results (MP4 225022 KB).

Immunomodulatory Treatment Versus Systemic Steroids in Inflammatory Choroidal Neovascularization Secondary to Idiopathic Multifocal Choroiditis

PURPOSE

To evaluate the influence of immunomodulatory therapy (IMT) on visual and treatment outcomes of inflammatory choroidal neovascularization (iCNV) in patients affected by multifocal choroiditis (MFC), and to compare them to patients treated with steroids as needed.

DESIGN

Multicenter retrospective matched cohort study.

METHODS

Patients affected by MFC with iCNV were divided into a IMT group and a "steroids as needed" group and matched according to the time between diagnosis and beginning of systemic treatment. Visual acuity (VA), number of anti-vascular endothelial growth factor (VEGF) intravitreal injections, and number of iCNV reactivations during 2 years of follow-up after treatment initiation were compared between the 2 groups.

RESULTS

A total of 66 eyes of 58 patients were included, equally divided into the 2 groups. Patients in the IMT group had a lower relative risk (RR) of iCNV reactivation (0.64, P = .04) and of anti-VEGF intravitreal injection retreatment (0.59, P = .02). Relapses of MFC-related inflammation were independently associated with a higher RRs of iCNV reactivation (1.22, P = .003). Final VA was higher in the IMT compared to the steroids as needed group (mean [SD], 69.1 [15.1] vs 77.1 [8.9] letters, P = .01), and IMT was associated with greater VA gains over time (+2.5 letters per year, P = .04).

CONCLUSIONS

IMT was associated with better visual and treatment outcomes in MFC complicated by iCNV compared to steroids as needed. The better outcomes of the IMT group and the association between MFC-related inflammation and iCNV reactivations highlight the need for tighter control of inflammation to prevent iCNV relapses and visual loss.

Topical Solution for Retinal Delivery: Bevacizumab and Ranibizumab Eye Drops in Anti-Aggregation Formula (AAF) in Rabbits

PURPOSE

Wet age-related macular degeneration (AMD) is a blinding retinal disease. Monthly intravitreal anti-VEGF antibody injections of bevacizumab (off-label) and ranibizumab (FDA approved) are the standard of care. Antibody aggregation may interfere with ocular absorption/distribution. This study assessed topical delivery of dilute antibodies to the posterior segment of rabbit eyes using a novel anti-aggregation formula (AAF).

METHODS

Bevacizumab, or biosimilar ranibizumab was diluted to 5 mg/ml in AAF. All rabbits were dosed twice daily. Substudy 1 rabbits (bevacizumab, 100 µl eye drops): Group 1 (bevacizumab/AAF, n = 6); Group 2 (bevacizumab/PBS, n = 7) and Vehicle control (AAF, n = 1). Substudy 2 rabbits (ranibizumab biosimilar/AAF, 50 µl eye drops): (ranibizumab biosimilar/AAF, n = 8). At 14.5 days, serum was drawn from rabbits. Aqueous, vitreous and retina samples were recovered from eyes and placed into AAF aliquots. Tissue analyzed using AAF as diluent.

RESULTS

Bevacizumab in AAF permeated/accumulated in rabbit aqueous, vitreous and retina 10 times more, than when diluted in PBS. AAF/0.1% hyaluronic acid eye drops, dosed twice daily, provided mean tissue concentrations (ng/g) in retina (29.50), aqueous (12.34), vitreous (3.46), and serum (0.28 ng/ml). Additionally, the highest concentration (ng/g) of ranibizumab biosimilar was present in the retina (18.0), followed by aqueous (7.82) and vitreous (1.47). Serum concentration was negligible (< 0.04 ng/ml). No irritation was observed throughout the studies.

CONCLUSIONS

Bevacizumab and ranibizumab, in an AAF diluent eye drop, can be delivered to the retina, by the twice daily dosing of a low concentration mAb formulation. This may prove to be an adjunct to intravitreal injections.

Microneedles: A minimally invasive delivery system for ocular treatment

This review article delves into the extensive use of microneedles in ocular therapy, emphasizing their efficacy in delivering drug substances to the posterior region of the eye. The conventional methods of drug delivery, while widely employed, are marred by inherent drawbacks such as neovascularization, abrasion, and infiltration. To address these limitations, the review explores various approaches to microneedle fabrication, shedding light on the diverse materials employed in the process. Furthermore, the article meticulously examines the delivered drug substances using distinct microneedle approaches and their applications in ocular therapy. By critically evaluating the drawbacks associated with conventional ophthalmic drug delivery, the review seeks to pave the way for a paradigm shift. It advocates for a novel approach centered around minimally invasive microneedles, presenting them as a promising solution to overcome the limitations of current drug delivery methods. The comprehensive discussion within this article not only offers insights into the fabrication techniques and materials used for microneedles but also provides a nuanced understanding of the applications and advantages associated with this innovative approach. As the exploration of microneedle technology continues to evolve, this review serves as a valuable resource for researchers, clinicians, and pharmaceutical professionals seeking to enhance ocular therapy by embracing the potential of minimally invasive microneedles.

Treatment Outcomes of Intravitreal Aflibercept for Uveitic Macular Edema

BACKGROUND/AIMS

To evaluate the efficacy of intravitreal aflibercept for UME (uveitic macular).

METHODS

A retrospective review of records of patients that received aflibercept for UME from January 2017 to August 2022 was conducted. The primary outcomes were mean change in visual acuity (VA) and central subfield thickness (CST) 6 and 12 months from the start of aflibercept treatment.

RESULTS

A total of 16 eyes of 12 patients were included. Indications for treatment included eyes that had previously demonstrated a history of elevated intraocular pressure secondary to a steroid response (n = 10) or a history of non-response or partial response to local corticosteroids (n = 6). Fifteen eyes (94%) demonstrated a reduction in CST after their initial injection. At 6-months, mean VA gain was 2.6 ± 7.7 letters (p = 0.24) from a mean VA of 67.8 ± 10.7 letters at baseline and mean CST improved by 97.6 ± 113.5 μm (p = 0.004) from 458.6 ± 123.1 μm at baseline. Fourteen eyes had 12-months of follow up and received a median of 4 injections over 12 visits. The mean VA at 12-months remained stable compared to baseline (mean change of -1.4 ± 12.5 letters (p = 0.87)) while the CST improved by a mean of 90.9 ± 114.6 μm (p = 0.053) compared to baseline.

CONCLUSION

Intravitreal aflibercept injections resulted in reduced central subfield thickness at all time-points. It appears to be an effective treatment alternative for UME, particularly for patients who are not responsive to local corticosteroids or who have contraindications to corticosteroid treatment.

Chemically induced cone degeneration in the 13-lined ground squirrel

Animal models of retinal degeneration are critical for understanding disease and testing potential therapies. Inducing degeneration commonly involves the administration of chemicals that kill photoreceptors by disrupting metabolic pathways, signaling pathways, or protein synthesis. While chemically induced degeneration has been demonstrated in a variety of animals (mice, rats, rabbits, felines, 13-lined ground squirrels (13-LGS), pigs, chicks), few studies have used noninvasive high-resolution retinal imaging to monitor the in vivo cellular effects. Here, we used longitudinal scanning light ophthalmoscopy (SLO), optical coherence tomography, and adaptive optics SLO imaging in the euthermic, cone-dominant 13-LGS (46 animals, 52 eyes) to examine retinal structure following intravitreal injections of chemicals, which were previously shown to induce photoreceptor degeneration, throughout the active season of 2019 and 2020. We found that iodoacetic acid induced severe pan-retinal damage in all but one eye, which received the lowest concentration. While sodium nitroprusside successfully induced degeneration of the outer retinal layers, the results were variable, and damage was also observed in 50% of contralateral control eyes. Adenosine triphosphate and tunicamycin induced outer retinal specific damage with varying results, while eyes injected with thapsigargin did not show signs of degeneration. Given the variability of damage we observed, follow-up studies examining the possible physiological origins of this variability are critical. These additional studies should further advance the utility of chemically induced photoreceptor degeneration models in the cone-dominant 13-LGS.

Association of diabetic retinopathy on all-cause and cause-specific mortality in older adults with diabetes: National Health and Nutrition Examination Survey, 2005-2008

To evaluate the effect of diabetic retinopathy (DR) status or severity on all-cause and cause-specific mortality among diabetic older adults in the United States using the most recent National Health and Nutrition Examination Survey (NHANES) follow-up mortality data. The severity of DR was graded according to the Early Treatment Diabetic Retinopathy Study (ETDRS) grading scale. Multiple covariate-adjusted Cox proportional hazards regression models, Fine and Gray competing risk regression models, and propensity score matching (PSM) methods were used to assess the risk of all-cause and cause-specific mortality in individuals with diabetes. All analyses adopted the weighted data and complex stratified design approach proposed by the NHANES guidelines. Time to death was calculated based on the time between baseline and date of death or December 31, 2019, whichever came first. Ultimately 1077 participants, representing 3,025,316 US non-hospitalized individuals with diabetes, were included in the final analysis. After a median follow-up of 12.24 years (IQR, 11.16-13.49), 379 participants were considered deceased from all-causes, with 43.90% suffering from DR, including mild DR (41.50%), moderate to severe DR (46.77%), and proliferative DR (PDR) (67.21%). DR was associated with increased all-cause, cardiovascular disease (CVD) and diabetes mellitus (DM)-specific mortality, which remained consistent after propensity score matching (PSM). Results of DR grading assessment suggested that the presence of mild, moderate to severe NPDR was significantly associated with increased risk of all-cause and CVD-specific mortality, while the presence and severity of any DR was associated with increased DM-specific mortality, with a positive trend. The presence of DR in elderly individuals with diabetes is significantly associated with the elevated all-cause and CVD mortality. The grading or severity of DR may reflect the severity of cardiovascular disease status and overall mortality risk in patients with diabetes.

Focused Ultrasound as a Novel Non-Invasive Method for the Delivery of Gold Nanoparticles to Retinal Ganglion Cells

Purpose

The blood-retinal barrier (BRB) restricts the delivery of intravenous therapeutics to the retina, necessitating innovative approaches for treating retinal disorders. This study sought to explore the potential of focused ultrasound (FUS) to non-invasively deliver intravenously administered gold nanoparticles (AuNPs) across the BRB. FUS-BRB modulation can offer a novel method for targeted retinal therapy.

Methods

AuNPs of different sizes and shapes were characterized, and FUS parameters were optimized to permeate the BRB without causing retinal damage in a rodent model. The delivery of 70-kDa dextran and AuNPs to the retinal ganglion cell (RGC) layer was visualized using confocal and two-photon microscopy, respectively. Histological and statistical analyses were conducted to assess the effectiveness and safety of the procedure.

Results

FUS-BRB modulation resulted in the delivery of dextran and AuNPs to the RGC and inner nuclear layer. Smaller AuNPs reached the retinal layers to a greater extent than larger ones. The delivery of dextran and AuNPs across the BRB with FUS was achieved without significant retinal damage.

Conclusions

This investigation provides the first evidence, to our knowledge, of FUS-mediated AuNP delivery across the BRB, establishing a foundation for a targeted and non-invasive approach to retinal treatment. The results contribute to developing promising non-invasive therapeutic strategies in ophthalmology to treat retinal diseases.

Translational Relevance

Modifying the BRB with ultrasound offers a targeted and non-invasive delivery strategy of intravenous therapeutics to the retina.

Multienzyme-Like Nanozyme Encapsulated Ocular Microneedles for Keratitis Treatment

Keratitis, an inflammation of the cornea caused by bacterial or fungal infections, is one of the leading causes of severe visual disability and blindness. Keratitis treatment requires both the prevention of infection and the reduction of inflammation. However, owing to their limited therapeutic functions, in addition to the ocular barrier, existing conventional medications are characterized by poor efficacy and low bioavailability, requiring high dosages or frequent topical treatment, which represents a burden on patients and increases the risk of side effects. In this study, manganese oxide nanocluster-decorated graphdiyne nanosheets (MnOx/GDY) are developed as multienzyme-like nanozymes for the treatment of infectious keratitis and loaded into hyaluronic acid and polymethyl methacrylate-based ocular microneedles (MGMN). MGMN not only exhibits antimicrobial and anti-inflammatory effects owing to its multienzyme-like activities, including oxidase, peroxidase, catalase, and superoxide dismutase mimics but also crosses the ocular barrier and shows increased bioavailability via the microneedle system. Moreover, MGMN is demonstrated to eliminate pathogens, prevent biofilm formation, reduce inflammation, alleviate ocular hypoxia, and promote the repair of corneal epithelial damage in in vitro, ex vivo, and in vivo experiments, thus providing a better therapeutic effect than commercial ophthalmic voriconazole, with no obvious microbial resistance or cytotoxicity.

Anti-VEGF and steroid combination therapy relative to anti-VEGF mono therapy for the treatment of refractory DME: A systematic review of efficacy and meta-analysis of safety

The aim of the study was to determine the efficacy and safety of combined anti-VEGF and steroid therapy in treatment refractory DME patients. We conducted a systematic review and meta-analysis of peer-reviewed articles reporting on visual, anatomical and adverse outcomes to compare the efficacy and safety of combined intravitreal anti-VEGF/steroids versus anti-VEGF monotherapy for refractory DME. Seven studies (4 RCTs and 3 observational studies) reporting on 452 eyes were included. Our systematic review showed that combination therapy is significantly more effective for anatomical outcomes in the treatment of resistant DME compared to anti-VEGF monotherapy in six studies. Two studies found that addition of intravitreal steroids promoted faster visual improvement, but not significantly better final visual outcomes compared to anti-VEGF monotherapy. Combination therapy was associated with a higher incidence of IOP-related adverse events (RR = 0.10, 95% CI = [0.02, 0.42], p = 0.002) and cataract-related adverse events (RR = 0.10, 95% CI = [0.01, 0.71], p = 0.02). Our systematic review and meta-analysis of seven studies and 452 eyes revealed that combination therapy of anti-VEGF and steroid intravitreal drugs in the management of treatment refractory DME resulted in superior anatomical outcomes in all but one study. Combination therapy led to superior short-term visual outcomes in two studies, while others reported no difference between treatment groups. Meta-analysis revealed that combination therapy was associated with more adverse events. Future research should provide guidance on the standard definitions for treatment resistance and therapeutic alternatives for DME patients with sub-optimal response to anti-VEGF treatment.

Effect of Intravitreal Anti-Endothelial Growth Factor Agents on Renal Function in Patients With Diabetes Mellitus

Introduction

Intravitreal administration of vascular endothelial growth factor inhibitors (anti-VEGF) is the treatment of choice in retinal pathology associated with type 2 diabetes mellitus (DM2). We aimed to analyze the effect of intravitreal anti-VEGF administration on renal function in patients with DM2.

Methods

This is a single-center retrospective and observational study of patients with DM2 with and without chronic kidney disease (CKD). We analyzed the evolution of renal function after anti-VEGF onset, compared with a control group.

Results

We included 45 patients (55.6% male) who received anti-VEGF therapy. Mean age was 74.4±11.5 (50-91) years. These were compared with 45 patients with similar characteristics. After 12 months, 76.3% had CKD with a mean reduction in estimated glomerular filtration rate (eGFR) of 19.4%. Nine patients (20%) had a >25% reduction in eGFR, and 3 patients (6.7%) had a >50% reduction in GFR. At 24 months, 80% of patients had CKD with a mean eGFR decrease of 28%. The mean eGFR slope of patients who had received anti-VEGF treatment was 10 ml/min/year compared to 1.5 ml/min/year in the control group (P < 0.05). After the first administration, 5 patients (17.2%) in the CKD group required renal replacement therapy during follow-up (mean time 22±12 months). Main risk factors for need of dialysis were age, presence of previous CKD, and baseline proteinuria.

Conclusion

Intravitreal anti-VEGF administration is a risk factor for CKD and rapid progression to end-stage kidney disease in patients with previous CKD. Knowing these drugs' implications is crucial to avoid CKD progression and opportunely limit their use in certain patients.

Preparation, characterisation, pharmacokinetics and distribution of esculin microspheres administered via intravitreal injection into rabbit brain

This study explored the distribution of esculin microspheres in rabbit brain tissue following intravitreal injection and investigated the possibility of direct entry of the drug into the brain through the eye, to develop a formulation with enhanced therapeutic efficacy against Parkinson's disease.Chitosan microspheres of esculin were prepared via an emulsification cross-linking method and their characteristics were evaluated, including angle of repose, bulk density, and swelling ratio. Furthermore, the pharmacokinetic parameters and brain tissue distribution in rabbits were compared among groups administered esculin eye drops, intravitreal esculin solution, and intravitreal esculin microspheres, to determine whether esculin could enter the brain through an ocular route.The results showed that the prepared esculin microspheres were spherical and had good fluidity. Notably, intravitreal administration enhanced the area under the curve (AUC) of esculin in the thalamus. Delivery through microspheres prolonged the drug retention time in both rabbit plasma and brain tissues, as well as the brain-targeting efficiency of esculin.The collective findings indicated that there may be a direct eye-brain pathway facilitating enter of esculin microspheres into brain tissue after intravitreal injection, supporting the utility of intravitreal esculin microspheres as an effective therapeutic formulation for Parkinson's disease, a long-term chronic condition.

Sphingosine-1-phosphate receptor 1/5 selective agonist alleviates ocular vascular pathologies

Ocular abnormal angiogenesis and edema are featured in several ocular diseases. S1P signaling via S1P1 likely is part of the negative feedback mechanism necessary to maintain vascular health. In this study, we conducted pharmacological experiments to determine whether ASP4058, a sphingosine 1-phosphate receptor 1/5 (S1P1/5) agonist, is useful in abnormal vascular pathology in the eye. First, human retinal microvascular endothelial cells (HRMECs) were examined using vascular endothelial growth factor (VEGF)-induced cell proliferation and hyperpermeability. ASP4058 showed high affinity and inhibited VEGF-induced proliferation and hyperpermeability of HRMECs. Furthermore, S1P1 expression and localization changes were examined in the murine laser-induced choroidal neovascularization (CNV) model, a mouse model of exudative age-related macular degeneration, and the efficacy of ASP4058 was verified. In the CNV model mice, S1P1 tended to decrease in expression immediately after laser irradiation and colocalized with endothelial cells and Müller glial cells. Oral administration of ASP4058 also suppressed vascular hyperpermeability and CNV, and the effect was comparable to that of the intravitreal administration of aflibercept, an anti-VEGF drug. Next, efficacy was also examined in a retinal vein occlusion (RVO) model in which retinal vascular permeability was increased. ASP4058 dose-dependently suppressed the intraretinal edema. In addition, it suppressed the expansion of the perfusion area observed in the RVO model. ASP4058 also suppressed the production of VEGF in the eye. Collectively, ASP4058 can be a potential therapeutic agent that normalizes abnormal vascular pathology, such as age-related macular degeneration and RVO, through its direct action on endothelial cells.

Effect of intravitreal injections due to neovascular age-related macular degeneration on retinal nerve fiber layer thickness and minimum rim width: a cross sectional study

PURPOSE

The present study tested the hypothesis that repeated anti-VEGF injections are associated with reduced retinal nerve fiber layer (RNFL) and minimum rim width (MRW) of the optic nerve head.

PATIENTS AND METHODS

Sixty-six patients with a history of intravitreal injections due to neovascular age-related macular degeneration were included. RNFL and MRW were measured using optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Mean global RNFL was 90.62 μm and both RNFL as well as MRW significantly decreased with advanced age (p = 0.005 and p = 0.019, respectively). Correlating for the number of injections, no significant impact on RNFL was found globally (p = 0.642) or in any of the sectors. In contrast, however, global MRW was significantly reduced with increasing numbers of intravitreal injections (p = 0.012). The same holds true when adjusted for the confounding factor age (RNFL p = 0.566 and MRW p = 0.023).

CONCLUSION

Our study shows that repeated intravitreal injections due to choroidal neovascularization seem to have a deleterious effect on MRW but not on RNFL. This suggests that MRW is a more sensitive marker than RNFL for evaluating the effect of frequent intravitreal injections on the optic nerve head since it seems to be the first structure affected.

Cardiovascular Outcomes with Intravitreal Anti-Vascular Endothelial Growth Factor Therapy in Patients with Diabetes: A Real-World Data Analysis

BACKGROUND

Anti-vascular endothelial growth factor (anti-VEGF) therapy is commonly used intravitreally for diabetic proliferative retinopathy, but when used systemically for treating cancers, an excess of cardiovascular disease (CVD) events has been noted. The latter is of concern for people with diabetes, who are at higher risk of CVD. This study aims to explore the relationship between incident CVD and intravitreal anti-VEGF therapy in patients with diabetes, compared to other therapies, using a large real-world global federated dataset.

METHODS

Data were analysed using TriNetX, a global electronic medical real-world ecosystem. The study included adults with diabetes and excluded those with a history of CVD prior to the time window of data extraction. Patients were categorised into two cohorts: anti-VEGF therapy or control cohort (laser or steroid therapies). The cohorts were 1:1 propensity score-matched for age, sex, ethnicity, body mass index, systolic blood pressure, HbA1c, and cardiovascular medications. Outcomes analysed at 1, 6 and 12 months were: (1) mortality; (2) acute myocardial infarction (MI); (3) cerebral infarction; and (4) heart failure. Relative risk analyses were performed using the built-in R statistical computing platform on TriNetX.

RESULTS

In patients with diabetes (n = 2205; mean age 58.8 ± 15.8, Std diff 0.05; 56% male), anti-VEGF therapy was associated with a numerical but non-statistically significant increased CVD risk over 1, 6, and 12 months: Mortality over 1 month (RR 1; 95% CI 0.42, 2.40), 6 months (RR 1.46; 95% CI 0.72, 2.95) and 12 months (RR 1.41; 95% CI 0.88, 2.27). There was no excess of acute MI over 1 (RR n/a: not applicable; 0/0: 0 events in the anti-VEGF group/0 events in the control group), 6 and 12 months (RR n/a; 0/10 events); cerebral infarction over 1, 6 months (RR n/a; 0/0 events), and 12 months (RR n/a; 0/10); and heart failure over 1 month (RR n/a; 0/0 events), 6 months (RR 1; 95% CI 0.42, 2.40) and 12 months (RR 1; 95% CI 0.42, 2.34).

CONCLUSIONS

There was no statistically significant risk of cardiovascular-related events in the short or medium term in patients with diabetes who received intravitreal anti-VEGF therapy, despite a small increase in the number of CVD events. Our study supports the real-world safety of intravitreal anti-VEGF therapy in patients with diabetes free of baseline CVD.

Polymeric microneedles for the eye: An overview of advances and ocular applications for minimally invasive drug delivery

Ocular drug delivery is challenging due to the presence of tissue barriers and clearance mechanisms. Most widely used topical formulations need frequent application because of poor permeability, short retention, and low bioavailability. Invasive intraocular injections and implants that deliver drugs at the target site are associated with infections, inflammation, and even vision loss post-use. These gaps can be addressed by a delivery platform that can efficiently deliver drug with minimal tissue damage. Microneedles were introduced as a delivery platform for overcoming dermal barriers with minimal tissue damage. After the successful clinical transition of microneedles in the transdermal drug delivery, they are now being extensively studied for ocular applications. The attributes of minimally invasive application and the capability to deliver a wide range of therapeutics make microneedles an attractive candidate for ocular drug delivery. The current manuscript provides a detailed overview of the recent advancements in the field of microneedles for ocular use. This paper reviews research focusing on polymeric microneedles and their pharmaceutical and biopharmaceutical properties. A brief discussion about their clinical translation and regulatory concerns is also covered. The multitude of research articles supports the fact that microneedles are a potential, minimally invasive drug delivery platform for ophthalmic use.

Purinergic P2X7 receptor involves in anti-retinal photodamage effects of berberine

Berberine (BBR) is a Chinese herb with antioxidant and anti-inflammatory properties. In a previous study, we found that BBR had a protective effect against light-induced retinal degeneration in BALB/c mice. The purinergic P2X7 receptor (P2X7R) plays a key role in retinal degeneration via inducing oxidative stress, inflammatory changes, and cell death. The aim of this study was to investigate whether BBR can induce protective effects in light damage experiments and whether P2X7R can get involved in these effects. C57BL/6 J mice and P2X7 knockout (KO) mice on the C57BL/6 J background were used. We found that BBR preserved the outer nuclear layer (ONL) thickness and retinal ganglion cells following light stimulation. Furthermore, BBR significantly suppressed photoreceptor apoptosis, pro-apoptotic c-fos expression, pro-inflammatory responses of Mϋller cells, and inflammatory factors (TNF-α, IL-1β). In addition, protein levels of P2X7R were downregulated in BBR-treated mice. Double immunofluorescence showed that BBR reduced overexpression of P2X7R in retinal ganglion cells and Mϋller cells. Furthermore, BBR combined with the P2X7R agonist BzATP blocked the effects of BBR on retinal morphology and photoreceptor apoptosis. However, in P2X7 KO mice, BBR had an additive effect resulting in thicker ONL and more photoreceptors. The data suggest that the P2X7 receptor is involved in retinal light damage, and BBR inhibits this process by reducing histological impairment, cell death, and inflammatory responses.

Inactivation of adenosine receptor 2A suppresses endothelial-to-mesenchymal transition and inhibits subretinal fibrosis in mice

Anti-vascular endothelial growth factor therapy has had a substantial impact on the treatment of choroidal neovascularization (CNV) in patients with neovascular age-related macular degeneration (nAMD), the leading cause of vision loss in older adults. Despite treatment, many patients with nAMD still develop severe and irreversible visual impairment because of the development of subretinal fibrosis. We recently reported the anti-inflammatory and antiangiogenic effects of inhibiting the gene encoding adenosine receptor 2A (Adora2a), which has been implicated in cardiovascular disease. Here, using two mouse models of subretinal fibrosis (mice with laser injury-induced CNV or mice with a deficiency in the very low-density lipoprotein receptor), we found that deletion of Adora2a either globally or specifically in endothelial cells reduced subretinal fibrosis independently of angiogenesis. We showed that Adora2a-dependent endothelial-to-mesenchymal transition contributed to the development of subretinal fibrosis in mice with laser injury-induced CNV. Deficiency of Adora2a in cultured mouse and human choroidal endothelial cells suppressed induction of the endothelial-to-mesenchymal transition. A metabolomics analysis of cultured human choroidal endothelial cells showed that ADORA2A knockdown with an siRNA reversed the increase in succinate because of decreased succinate dehydrogenase B expression under fibrotic conditions. Pharmacological inhibition of ADORA2A with a small-molecule KW6002 in both mouse models recapitulated the reduction in subretinal fibrosis observed in mice with genetic deletion of Adora2a. ADORA2A inhibition may be a therapeutic approach to treat subretinal fibrosis associated with nAMD.

Comparison of Widefield OCT Angiography Features Between Severe Non-Proliferative and Proliferative Diabetic Retinopathy

INTRODUCTION

There is a high and ever-increasing global prevalence of diabetic retinopathy (DR) and invasive imaging techniques are often required to confirm the presence of proliferative disease. The aim of this study was to explore the images of a rapid and non-invasive technique, widefield optical coherence tomography angiography (OCT-A), to study differences between patients with severe non-proliferative and proliferative DR (PDR).

METHODS

We conducted an observational longitudinal study from November 2022 to March 2023. We recruited 75 patients who were classified into a proliferative group (28 patients) and severe non-proliferative group (47 patients). Classification was done by specialist clinicians who had full access to any multimodal imaging they required to be confident of their diagnosis, including fluorescein angiography. For all patients, we performed single-shot 4 × 4 and 10 × 10 mm (widefield) OCT-A imaging and when possible, the multiple images required for mosaic 17.5 × 17.5 mm (ultra widefield) OCT-A imaging. We assessed the frequency with which proliferative disease was identifiable solely from these OCT-A images and used custom-built MATLAB software to analyze the images and determine computerized metrics such as density and intensity of vessels, foveal avascular zone, and ischemic areas.

RESULTS

On clinically assessing the OCT-A 10 × 10 fields, we were only able to detect new vessels in 25% of known proliferative images. Using ultra-widefield mosaic images, however, we were able to detect new vessels in 100% of PDR patients. The image analysis metrics of 4 × 4 and 10 × 10 mm images did not show any significant differences between the two clinical groups. For mosaics, however, there were significant differences in the capillary density in patients with PDR compared to severe non-PDR (9.1% ± 1.9 in the PDR group versus 11.0% ± 1.9 for severe group). We also found with mosaics a significant difference in the metrics of ischemic areas; average area of ischemic zones (253,930.1 ± 108,636 for the proliferative group versus 149,104.2 ± 55,101.8 for the severe group.

CONCLUSIONS

Our study showed a high sensitivity for detecting PDR using only ultra-widefield mosaic OCT-A imaging, compared to multimodal including fluorescein angiography imaging. It also suggests that image analysis of aspects such as ischemia levels may be useful in identifying higher risk groups as a warning sign for future conversion to neovascularization.

A real-world disproportionality analysis of anti-VEGF drugs from the FDA Adverse Event Reporting System

BACKGROUND

The association between anti-vascular endothelial growth factor (VEGF) drugs and ocular adverse events (AEs) has been reported, but large real-world studies of their association with systemic AEs are still lacking.

METHODS

A disproportionality analysis of reports from the FDA Adverse Event Reporting System from January 2004 to September 2021 was conducted to detect the significant ADR signals with anti-VEGF drugs (including aflibercept, bevacizumab, brolucizumab, pegaptanib, and ranibizumab).

RESULTS

A total of 2980 reported cases with 7125 drug-AEs were included. Five drugs were all associated with eye disorders, and pegaptanib and ranibizumab were also associated with cardiac disorders. For ranibizumab, pegaptanib, bevacizumab and aflibercept, the proportions of cardiac AEs were 8.57%, 5.62%, 3.43% and 3.20%, respectively, and the proportions of central nervous AEs were 8.81%, 7.41, 5.86% and 5.68%, respectively. In multiple comparisons, ranibizumab was significantly higher than bevacizumab and aflibercept in the proportion of cardiac AEs (P < 0.001), and ranibizumab was significantly higher than aflibercept in central nervous AEs (P < 0.001).

CONCLUSIONS

Our findings support the associations between anti-VEGF drugs and ocular AEs, cardiac AEs, and central nervous AEs. After intravitreal injection, attention should not only be paid to ocular symptoms, but also to systemic symptoms.

Next generation therapeutics for retinal neurodegenerative diseases

Neurodegenerative diseases affecting the visual system encompass glaucoma, macular degeneration, retinopathies, and inherited genetic disorders such as retinitis pigmentosa. These ocular pathologies pose a serious burden of visual impairment and blindness worldwide. Current treatment modalities include small molecule drugs, biologics, or gene therapies, most of which are administered topically as eye drops or as injectables. However, the topical route of administration faces challenges in effectively reaching the posterior segment and achieving desired concentrations at the target site, while injections and implants risk severe complications, such as retinal detachment and endophthalmitis. This necessitates the development of innovative therapeutic strategies that can prolong drug release, deliver effective concentrations to the back of the eye with minimal systemic exposure, and improve patient compliance and safety. In this review, we introduce retinal degenerative diseases, followed by a discussion of the existing clinical standard of care. We then delve into detail about drug and gene delivery systems currently in preclinical and clinical development, including formulation and delivery advantages/drawbacks, with a special emphasis on potential for clinical translation.

Ultrahigh-Efficacy VEGF Neutralization Using Carbonized Nanodonuts: Implications for Intraocular Anti-Angiogenic Therapy

Ocular angiogenesis, associated with diseases such as retinopathy of prematurity and diabetic retinopathy, is a leading cause of irreversible vision loss. Herein, carbon nanodonuts (CNDs) with a donut-shaped structure are synthesized using sodium alginate (SA) and 1,8-diaminooctane (DAO) through a one-step thermal process. The formation of SA/DAO-CNDs occurs through a crosslinking reaction between SA and DAO, creating amide bonds followed by partial carbonization. In human retinal pigment epithelial cells exposed to H2 O2 or lipopolysaccharide, the SA/DAO-CNDs display a more than fivefold reduction in reactive oxygen species and proinflammatory cytokines, such as IL-6 and IL-1β, when compared to carbonized nanomaterials produced exclusively from SA. Furthermore, the CNDs effectively inhibit vascular endothelial growth factor A-165 (VEGF-A165 )-induced cell migration and tube formation in human umbilical vein endothelial cells due to their strong affinity for VEGF-A165 , with a dissociation constant of 2.2 × 10-14  M, over 1600 times stronger than the commercial drug bevacizumab (Avastin). Trypsin digestion coupled with LC-MS/MS analysis reveals that VEGF-A165 interacts with SA/DAO-CNDs through its heparin-binding domain, leading to activity loss. The SA/DAO-CNDs demonstrate excellent biocompatibility and potent anti-angiogenic effects in chicken embryos and rabbit eyes. These findings suggest that SA/DAO-CNDs hold promise as a therapeutic agent for treating various angiogenesis-related ocular diseases.

A bioengineered anti-VEGF protein with high affinity and high concentration for intravitreal treatment of wet age-related macular degeneration

Intravitreal (IVT) injection of anti-vascular endothelial growth factor (anti-VEGF) has greatly improved the treatment of many retinal disorders, including wet age-related macular degeneration (wAMD), which is the third leading cause of blindness. However, frequent injections can be difficult for patients and may lead to various risks such as elevated intraocular pressure, infection, and retinal detachment. To address this issue, researchers have found that IVT injection of anti-VEGF proteins at their maximally viable concentration and dose can be an effective strategy. However, the intrinsic protein structure can limit the maximum concentration due to stability and solution viscosity. To overcome this challenge, we developed a novel anti-VEGF protein called nanoFc by fusing anti-VEGF nanobodies with a crystallizable fragment (Fc). NanoFc has demonstrated high binding affinity to VEGF165 through multivalency and potent bioactivity in various bioassays. Furthermore, nanoFc maintains satisfactory chemical and physical stability at 4°C over 1 month and is easily injectable at concentrations up to 200 mg/mL due to its unique architecture that yields a smaller shape factor. The design of nanoFc offers a bioengineering strategy to ensure both strong anti-VEGF binding affinity and high protein concentration, with the goal of reducing the frequency of IV injections.

Topical Ophthalmic Liposomes Dual-Modified with Penetratin and Hyaluronic Acid for the Noninvasive Treatment of Neovascular Age-Related Macular Degeneration

Introduction

Since intrinsic ocular barrier limits the intraocular penetration of therapeutic protein through eye drops, repeated intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents are the standard therapy for neovascular age-related macular degeneration (nAMD), which are highly invasive and may cause particular ocular complications, leading to poor patient compliance.

Methods

Using Penetratin (Pen) as the ocular penetration enhancer and hyaluronic acid (HA) as the retina-targeting ligand, a dual-modified ophthalmic liposome (Penetratin hyaluronic acid-liposome/Conbercept, PenHA-Lip/Conb) eye drop was designed to non-invasively penetrate the ocular barrier and deliver anti-VEGF therapeutic agents to the targeted intraocular tissue.

Results

PenHA-Lip effectively penetrates the ocular barrier and targets the retinal pigment epithelium via corneal and non-corneal pathways. After a single topical administration of conbercept-loaded PenHA-Lip (PenHA-Lip/Conb), the intraocular concentration of conbercept peaked at 18.74 ± 1.09 ng/mL at 4 h, which is 11.55-fold higher than unmodified conbercept. In a laser-induced choroidal neovascularization (CNV) mouse model, PenHA-Lip/Conb eye drops three times daily for seven days inhibited CNV formation and progression without any significant tissue toxicity and achieved an equivalent effect to a single intravitreal conbercept injection.

Conclusion

PenHA-Lip efficiently and safely delivered conbercept to the posterior eye segment and may be a promising noninvasive therapeutic option for nAMD.

Hydrogel-Based Therapy for Age-Related Macular Degeneration: Current Innovations, Impediments, and Future Perspectives

Age-related macular degeneration (AMD) is an ocular disease that leads to progressive photoreceptor death and visual impairment. Currently, the most common therapeutic strategy is to deliver anti-vascular endothelial growth factor (anti-VEGF) agents into the eyes of patients with wet AMD. However, this treatment method requires repeated injections, which potentially results in surgical complications and unwanted side effects for patients. An effective therapeutic approach for dry AMD also remains elusive. Therefore, there is a surge of enthusiasm for the developing the biodegradable drug delivery systems with sustained release capability and develop a promising therapeutic strategy. Notably, the strides made in hydrogels which possess intricate three-dimensional polymer networks have profoundly facilitated the treatments of AMD. Researchers have established diverse hydrogel-based delivery systems with marvelous biocompatibility and efficacy. Advantageously, these hydrogel-based transplantation therapies provide promising opportunities for vision restoration. Herein, we provide an overview of the properties and potential of hydrogels for ocular delivery. We introduce recent advances in the utilization of hydrogels for the delivery of anti-VEGF and in cell implantation. Further refinements of these findings would lay the basis for developing more rational and curative therapies for AMD.

Endophthalmitis following same-day bilateral anti-VEGF injections: a systematic review

PURPOSE

To review the risk of endophthalmitis in same-day bilateral anti-VEGF injections.

METHODS

We searched 12 literature databases for studies on the risk of endophthalmitis after same-day bilateral intravitreal anti-VEGF injections. Data extraction was made independently by two authors and discussed afterward until reaching consensus.

RESULTS

Seventeen studies were included with a total of 138,478 intravitreal anti-VEGF injections (69,239 bilateral injections sessions) given in at least 7579 patients. In total, 33 cases of endophthalmitis had occurred, and no cases were bilateral. The incidence of endophthalmitis ranged from 0 to 0.53% per intravitreal injection across studies.

CONCLUSIONS

We suggest that clinicians can consider same-day treatment of both eyes of patients in need of bilateral intravitreal anti-VEGF injection therapy, but larger studies are needed to quantify the exact risk of endophthalmitis.

LONG-TERM USE OF ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

Although pivotal trials have demonstrated efficacy of anti-vascular endothelial growth factor therapy in neovascular age-related macular degeneration, there is a paucity of clinical data about the long-term (>5 years) treatment.

METHODS

Retrospective analysis of all patients with neovascular age-related macular degeneration who were actively treated, had received >40 anti-vascular endothelial growth factor injections, and were followed for ≥5 years. Snellen-corrected visual acuity, initial drug choice, and times elapsed between treatments were collected. Rates of endophthalmitis and outcomes of submacular hemorrhage were also evaluated.

RESULTS

A total of 88 patients (162 eyes) met the inclusion criteria: the average patient age was 86.3 years with an average follow-up period of 7.6 years. The average total number of injections per eye was 69 (18.0 SD); a total of 11,208 injections were given throughout the study period, and 6 cases (0.05%) of endophthalmitis were observed. Overall, there was a clinical and statistical difference in average Snellen-corrected visual acuity at Injections #2,#3, #4, #5, #6, #10, and #20, as compared with baseline ( P = 0.03, P < 0.01, P = 0.02, P < 0.01, P = 0.01, P = 0.01, P < 0.01, respectively). Patients in the Snellen-corrected visual acuity subgroup 20/20 to 20/40 maintained vision until injection #30. Seven eyes experienced a visually significant submacular hemorrhage.

CONCLUSION

This neovascular age-related macular degeneration cohort received on average eight anti-vascular endothelial growth factor injections per year for approximately 8 years; eyes with good (≥20/40) initial baseline vision maintained their visual acuity, whereas those with worse Snellen-corrected visual acuity (≤20/50) had a robust initial improvement that diminished with time. Most patients were maintained on the same initial drug of choice and the rate of endophthalmitis was low.

The role of Keap1-Nrf2 signaling pathway during the progress and therapy of diabetic retinopathy

Diabetic retinopathy is a complex and progressive ocular complication of diabetes mellitus and is a leading cause of blindness in people of working age worldwide. The pathophysiology of diabetic retinopathy involves multifactorial processes, including oxidative stress, inflammation and vascular abnormalities. Understanding the underlying molecular mechanisms involved in its pathogenesis is essential for the development of effective therapeutic interventions. One of the pathways receiving increasing attention is the Keap1-Nrf2 signaling pathway, which regulates the cellular response to oxidative stress by activating Nrf2. In this review, we analyze the current evidence linking Keap1-Nrf2 signaling pathway dysregulation to diabetic retinopathy. In addition, we explore the potential therapeutic implications and the challenges of targeting this pathway for disease management. A comprehensive understanding of the molecular mechanisms of diabetic retinopathy and the therapeutic potential of the Keap1-Nrf2 pathway may pave the way for innovative and effective interventions to combat this vision-threatening disease.

Levosulpiride for the treatment of diabetic macular oedema: a phase 2 randomized clinical trial

BACKGROUND/OBJECTIVE

The prokinetic levosulpiride elevates vasoinhibin levels in the vitreous of patients with proliferative diabetic retinopathy (PDR) suggesting clinical benefits due to the anti-vasopermeability and anti-angiogenic properties of vasoinhibin. We investigated the biological activity of levosulpiride in centre-involving diabetic macular oedema (DME).

PATIENTS/METHODS

Prospective, randomized, double-blinded, dual-centre, phase 2 trial in patients with centre-involving DME orally treated with placebo (n = 17) or levosulpiride (n = 17) for 8 weeks or in patients with PDR undergoing elective pars plana vitrectomy and receiving placebo (n = 18) or levosulpiride (n = 18) orally for the 1 week before vitrectomy.

RESULTS

Levosulpiride improved changes from baseline in best-corrected visual acuity (p ≤ 0.037), central foveal thickness (CFT, p ≤ 0.013), and mean macular volume (MMV, p ≤ 0.002) at weeks 4, 6, and 8 compared to placebo. At 8 weeks, the proportion of eyes gaining ≥5 ETDRS letters at 4 m (41% vs. 28%), losing ≥21 μm in CFT (55% vs. 28%), and dropping ≥0.06 mm3 in MMV (65% vs. 29%) was higher after levosulpiride than placebo. The overall grading of visual and structural parameters improved with levosulpiride (p = 0.029). Levosulpiride reduced VEGF (p = 0.025) and PlGF (p = 0.008) levels in the vitreous of PDR patients. No significant adverse side-effects were detected.

CONCLUSIONS

Oral levosulpiride for 8 weeks improved visual and structural outcomes in patients with centre-involving DME by mechanisms that may include intraocular upregulation of vasoinhibin and downregulation of VEGF and PlGF. Larger clinical trials evaluating long-term efficacy and safety are warranted.

The Inflammatory and Cytological Effect of Repeated Povidone-Iodine Application in Patients Receiving Intravitreal Injections

OBJECTIVE

To investigate the effect of repeated povidone-iodine (PVI) application on the ocular surface parameters of patients who received intravitreal injections.

MATERIALS AND METHODS

In this prospective study, 52 eyes of 52 patients with age-related macular degeneration who underwent unilateral intravitreal injection at least three times in the last 1 year (intravitreal injection [IVI] group), 52 fellow eyes with no previous intravitreal injection (NIVI group), and 51 eyes of 51 healthy subjects (control) were included. Tear break-up time (TBUT), the Schirmer test, the Oxford staining score, the Ocular Surface Disease Index questionnaire, conjunctival impression cytology, and tear inflammatory cytokine levels (interleukin [IL]-1β and IL-6) were analyzed in all participants.

RESULTS

The IVI group had lower TBUT and higher Oxford staining score than the NIVI and control groups ( P <0.05). No significant difference was found between the groups in the Schirmer test ( P =0.161). Conjunctival impression cytology analysis revealed that the IVI group had a significantly lower goblet cell count and significantly higher Nelson staging result than the NIVI and control groups ( P <0.05). As a result of tear cytokine analysis, although IVI and NIVI groups had higher IL-1β and IL-6 levels than the control group ( P <0.05), there was no difference between NIVI and IVI groups ( P ≥0.05).

CONCLUSIONS

Repeated PVI application caused cytotoxic injury to the ocular surface, resulting in goblet cell loss and squamous metaplasia of epithelial cells. As a result, the stability of the tear film layer was found to be impaired and ocular surface-related symptoms developed in patients.

[Iatrogenic retinal defects after intravitreal operative drug injections]

BACKGROUND

Intravitreal operative drug injections represent one of the most frequently performed medical interventions. The risk profile is low. In addition to intraocular pressure elevation, the most frequent complications include exogenous endophthalmitis, vitreous hemorrhage and rhegmatogenous retinal detachment. Furthermore, isolated cases of lens injuries, macular holes associated with vitreoretinal traction and peripheral retinal defects have been described. In the present case series sharp iatrogenic macular and retinal defects are described.

METHODS

Retrospective multicenter case collection of patients with iatrogenic retinal defects after intravitreal injections from 2016 to 2023.

RESULTS

Iatrogenic retinal trauma after intravitreal injections for treatment of neovascular age-related macular degeneration was identified in 9 cases (72 years ± 8.1, 3 eyes pseudophakic). While sharp injuries within the macula occurred in six cases, extramacular lesions were detected in the other cases.

CONCLUSION

Iatrogenic retinal and macular injuries are rare complications of intravitreal injections and when correctly carried out are preventable, especially with respect to use of cannulas and the choice of the distance from the limbus.

A prospective observation of influence of anti-VEGF on optic disc vasculature in nAMD patients

BACKGROUND

This study aims to investigate the short-term changes in relatively normal retinal vessels following anti-vascular endothelial growth factor (anti-VEGF) therapy in nAMD patients, an area that currently represents a research gap.

METHODS

In this prospective study, we enrolled patients newly diagnosed with neovascular age-related macular degeneration (nAMD) and received standardized monthly anti-VEGF therapy for three months. Follow-ups were conducted at baseline and 1-week, 1-month, 2-months and 3-months post first injection. Assessment indicators included radial peripapillary capillary vascular density (RPC-VD) and retinal nerve fiber layer (RNFL) thickness in different optic disk regions using optical coherence tomography angiography, as well as intraocular pressure (IOP).

RESULTS

68 nAMD patients (68 eyes) were included in this study. Significant reductions of RPC-VD and increases of RNFL thickness primarily in the nasal regions were observed 1-week post anti-VEGF (adjusted P < 0.05). Significant negative correlations were found between 1-week changes in RPC-VD and RNFL thickness in the nasal sectors (P < 0.05). From 1 to 3 months post-injection, RPC-VD and RNFL thickness essentially returned to baseline levels. Throughout the follow-up periods, IOP remained stable (P > 0.05).

CONCLUSION

Anti-VEGF treatments transiently influence the relatively normal retinal vessels, which might lead to nerve fiber edema, predominantly on the nasal side of the optic disk.

Exploring the Spectrum of VEGF Inhibitors' Toxicities from Systemic to Intra-Vitreal Usage in Medical Practice

The use of Vascular Endothelial Growth Factor inhibitors (VEGFi) has become prevalent in the field of medicine, given the high incidence of various pathological conditions necessitating VEGF inhibition within the general population. These conditions encompass a range of advanced neoplasms, such as colorectal cancer, non-small cell lung cancer, renal cancer, ovarian cancer, and others, along with ocular diseases. The utilization of VEGFi is not without potential risks and adverse effects, requiring healthcare providers to be well-prepared for identification and management. VEGFi can be broadly categorized into two groups: antibodies or chimeric proteins that specifically target VEGF (bevacizumab, ramucirumab, aflibercept, ranibizumab, and brolucizumab) and non-selective and selective small molecules (sunitinib, sorafenib, cabozantinib, lenvatinib, regorafenib, etc.) designed to impede intracellular signaling of the VEGF receptor (RTKi, receptor tyrosine kinase inhibitors). The presentation and mechanisms of adverse effects resulting from VEGFi depend primarily on this distinction and the route of drug administration (systemic or intra-vitreal). This review provides a thorough examination of the causes, recognition, management, and preventive strategies for VEGFi toxicities with the goal of offering support to oncologists in both clinical practice and the design of clinical trials.

Smart biodegradable hydrogels: Drug-delivery platforms for treatment of chronic ophthalmic diseases affecting the back of the eye

This paper aims to develop smart hydrogels based on functionalized hyaluronic acid (HA) and PLGA-PEG-PLGA (PLGA,poly-(DL-lactic-co-glycolic acid); PEG,polyethylene glycol) for use as intraocular drug-delivery platforms. Anti-inflammatory agent dexamethasone-phosphate (0.2 %w/v) was the drug selected to load on the hydrogels. Initially, different ratios of HA-aldehyde (HA-CHO) and thiolated-HA (HA-SH) were assayed, selecting as optimal concentrations 2 and 3 % (w/v), respectively. Optimized HA hydrogel formulations presented fast degradation (8 days) and drug release (91.46 ± 3.80 % in 24 h), thus being suitable for short-term intravitreal treatments. Different technology-based strategies were adopted to accelerate PLGA-PEG-PLGA water solubility, e.g. substituting PEG1500 in synthesis for higher molecular weight PEG3000 or adding cryopreserving substances to the buffer dissolution. PEG1500 was chosen to continue optimization and the final PLGA-PEG-PLGA hydrogels (PPP1500) were dissolved in trehalose or mannitol carbonate buffer. These presented more sustained release (71.77 ± 1.59 % and 73.41 ± 0.83 % in 24 h, respectively) and slower degradation (>14 days). In vitro cytotoxicity studies in the retinal-pigmented epithelial cell line (RPE-1) demonstrated good tolerance (viability values > 90 %). PLGA-PEG-PLGA hydrogels are proposed as suitable candidates for long-term intravitreal treatments. Preliminary wound healing studies with PLGA-PEG-PLGA hydrogels suggested faster proliferation at 8 h than controls.

Current Insights into Targeting Strategies for the Effective Therapy of Diseases of the Posterior Eye Segment

The eye is one a unique sophisticated human sense organ with a complex anatomical structure. It is encased by variety of protective barriers as responsible for vision. There has been a paradigm shift in the prevalence of several major vision threatening ocular conditions with enhanced reliance on computer-based technologies in our workaday life and work-from-home modalities although aging, pollution, injury, harmful chemicals, lifestyle changes will always remain the root cause. Treating posterior eye diseases is a challenge faced by clinicians worldwide. The clinical use of conventional drug delivery systems for posterior eye targeting is restricted by the ocular barriers. Indeed, for overcoming various ocular barriers for efficient delivery of the therapeutic moiety and prolonged therapeutic effect requires prudent and target-specific approaches. Therefore, for efficient drug delivery to the posterior ocular segment, advancements in the development of sustained release and nanotechnology-based ocular drug delivery systems have gained immense importance. Therapeutic efficacy and patient compliance are of paramount importance in clinical translation of these investigative drug delivery systems. This review provides an insight into the various strategies employed for improving the treatment efficacies of the posterior eye diseases. Various drug delivery systems such as systemic and intraocular injections, implants have demonstrated promising outcomes, along with that they have also exhibited side-effects, limitations and strategies employed to overcome them are discussed in this review. The application of artificial intelligence-based technologies along with an appreciation of disease, delivery systems, and patient-specific outcomes will likely enable more effective therapy for targeting the posterior eye segment.