Complications of intravitreal injections in patients with diabetes

Effectiveness of carbonic anhydrase inhibitor loaded nanoparticles in the treatment of diabetic retinopathy

Diabetic Retinopathy (DRP) is a disease consisting of all the structural and functional changes that develop in the retinal layer of the eye due to diabetes. DRP is the most important cause of blindness between the ages of 20-74 in the world, and the most successful standard treatment option in the treatment of DRP is intravitreal injections. To synthesize acetazolamide loaded nanoparticles to be applied intravitreal treatment of DRP and to examine thein vitroefficacy of the nanoparticles. ACZ loaded PHBV nanoparticles (PHBV-ACZ NPs) formulations were prepared. Nanoparticles with a particle size of 253.20 ± 0.55 nm. A DRP model was established and characterized in HRMEC cells. The effect of the nanoparticles on permeability has been investigated and carrier proteins in BRB due to the development of DRP has been investigated. To establish thein vitroDRP model, HRMEC was stimulated with Recombinant human 165 Vascular Endothelial Growth Factor (VEGF), thereby temporarily reducing the expression levels of endothelial junction proteins, increasing the number of intercellular spaces in the monolayers of HRMECs. It was determined that after the cells were exposed to Carbonic anhydrase inhibitors (CAI) loaded nanoparticles, permeability decreased and protein expression increased.

Subconjunctival therapy by cubic liquid crystalline nanoparticles to deliver Triamcinolone acetonide for the management of diabetic Retinopathy: In vivo evidences

The expression of inflammatory markers and vascular endothelial growth factor (VEGF) was found to be upregulated in various posterior ocular disorders, including diabetic retinopathy (DR). Effective delivery of therapeutic agents to the retina poses a significant challenge in ophthalmic drug delivery due to biological ocular barriers. Triamcinolone acetonide (TA) was selected as the model corticosteroid drug targeting cytokines and VEGF in DR. However, despite TA's low molecular weight and hydrophobicity, which enable it to bypass the conjunctival epithelial barrier, it doesn't efficiently exert its effect at the target site. Nanocarriers have emerged as a solution to enhance drug delivery to the retina and improve bioavailability. This study aimed to compare the effects of Triamcinolone-loaded cubic liquid crystalline nanoparticles (TA-cubic LCNPs) and TA-Suspension in an experimental DR model administered via the subconjunctival (SCJ) route. The results demonstrated that TA-cubic LCNPs enhanced TA periocular delivery efficacy by reducing inflammatory and VEGF markers through the advanced glycation end products (AGE)/protein kinase C pathway. They were identified as promising nano-carriers, exhibiting potential for targeted delivery to the retina.

Comparison of Diabetic Retinopathy Lesions Identified Using Ultrawide Field Imaging and Optical Coherence Tomography Angiography

INTRODUCTION

Optical coherence tomography (OCT) angiography (OCTA) has the potential to influence the diagnosis and management of diabetic eye disease. This study aims to determine the correlation between diabetic retinopathy (DR) findings on ultrawide field (UWF) color photography (UWF-CP), UWF fluorescein angiography (UWF-FA), and OCTA.

METHODS

This is a cross-sectional, prospective study. One hundred and fourteen eyes from 57 patients with diabetes underwent mydriatic UWF-CP, UWF-FA, and OCTA. DR severity was assessed. Ischemic areas were identified on UWF-FA using ImageJ and the nonperfusion index (NPI) was calculated. Diabetic macular edema (DME) was assessed using OCT. Superficial capillary plexus vessel density (VD), vessel perfusion (VP), and foveal avascular zone (FAZ) area were automatically measured on OCTA. Pearson correlation coefficient between the imaging modalities was determined.

RESULTS

Forty-five eyes were excluded due to non-DR findings or prior laser photocoagulation; 69 eyes were analyzed. DR severity was associated with larger NPI (r = 0.55944, p < 0.0001) even after distinguishing between cones (Cone Nonperfusion Index [CPI]: r = 0.55617, p < 0.0001) and rods (Rod Nonperfusion Index [RPI]: r = 0.55285, p < 0.0001). In eyes with nonproliferative DR (NPDR), NPI is correlated with DME (r = 0.51156, p = 0.0017) and central subfield thickness (CST) (r = 0.67496, p < 0.0001). UWF-FA macular nonperfusion correlated with NPI (r = 0.42899, p = 0.0101), CPI (r = 0.50028, p = 0.0022), and RPI (r = 0.49027, p = 0.0028). Central VD and VP correlated with the DME presence (r = 0.52456, p < 0.0001; r = 0.51952, p < 0.0001) and CST (r = 0.50133, p < 0.0001; r = 0.48731, p < 0.0001). Central VD and VP were correlated with macular nonperfusion (r = 0.44503, p = 0.0065; r = 0.44239, p = 0.0069) in eyes with NPDR. Larger FAZ was correlated with decreased central VD (r = -0.60089, p = 0.0001) and decreased central VP (r = -0.59224, p = 0.0001).

CONCLUSION

UWF-CP, UWF-FA, and OCTA findings provide relevant clinical information on diabetic eyes. Nonperfusion on UWF-FA is correlated with DR severity and DME. OCTA metrics of the superficial capillary plexus correlate with the incidence of DME and macular ischemia.

Systemic Outcomes of Intravitreal Injections of Dexamethasone and Anti-Vascular Endothelial Growth Factor

INTRODUCTION

Intravitreal dexamethasone and anti-vascular endothelial growth factor (anti-VEGF) medications have revolutionized ocular disease management and favorable ocular safety profiles, but few studies have compared their systemic adverse events (SAEs). This study investigated the SAEs of intravitreal dexamethasone and anti-VEGFs by using real-world data.

METHODS

This retrospective cohort study sourced medical records from the largest multi-institutional database in Taiwan. Patients who received intravitreal dexamethasone (n = 137) or anti-VEGFs (n = 10,345) between 2014 and 2019 were enrolled. Propensity score matching was performed to achieve homogeneity between the two groups. Subdistribution hazard ratios (SHRs) and 95% confidence intervals (CIs) were calculated using the Fine-Gray model. Systemic as well as ocular clinical events and systemic biomarkers after 1-year follow-up were compared.

RESULTS

Both groups demonstrated comparable risks of major cardiac adverse events (SHR 1.57, 95% CI 0.29-8.55), heart failure (SHR 0.62, 95% CI 0.07-5.33), major bleeding (SHR 0.23, 95% CI 0.03-1.77), all-cause admission (SHR 0.73, 95% CI 0.41-1.30), and all-cause death (SHR 2.11, 95% CI 0.35-12.71). There were no significant differences in longitudinal changes in systolic and diastolic blood pressure, glycated hemoglobin, low-density lipoprotein, estimated glomerular filtration rate, or alanine aminotransferase between the groups. Both groups had a similar incidence of cataract surgery. Although the dexamethasone group exhibited a relatively high prevalence of antiglaucomatous medication use, there was not a significantly higher incidence of glaucoma surgery.

CONCLUSION

Intravitreal dexamethasone and anti-VEGF medications had comparable systemic safety profiles in our study. Both drugs represent efficacious and safe therapies for ocular diseases.

Systemic C-peptide supplementation ameliorates retinal neurodegeneration by inhibiting VEGF-induced pathological events in diabetes

Diabetic retinopathy (DR) is caused by retinal vascular dysfunction and neurodegeneration. Intraocular delivery of C-peptide has been shown to be beneficial against hyperglycemia-induced microvascular leakage in the retina of diabetes; however, the effect of C-peptide on diabetes-induced retinal neurodegeneration remains unknown. Moreover, extraocular C-peptide replacement therapy against DR to avoid various adverse effects caused by intravitreal injections has not been studied. Here, we demonstrate that systemic C-peptide supplementation using osmotic pumps or biopolymer-conjugated C-peptide hydrogels ameliorates neurodegeneration by inhibiting vascular endothelial growth factor-induced pathological events, but not hyperglycemia-induced vascular endothelial growth factor expression, in the retinas of diabetic mice. C-peptide inhibited hyperglycemia-induced activation of macroglial and microglial cells, downregulation of glutamate aspartate transporter 1 expression, neuronal apoptosis, and histopathological changes by a mechanism involving reactive oxygen species generation in the retinas of diabetic mice, but transglutaminase 2, which is involved in retinal vascular leakage, is not associated with these pathological events. Overall, our findings suggest that systemic C-peptide supplementation alleviates hyperglycemia-induced retinal neurodegeneration by inhibiting a pathological mechanism, involving reactive oxygen species, but not transglutaminase 2, in diabetes.

Long-acting formulation strategies for protein and peptide delivery in the treatment of PSED

The invigoration of protein and peptides in serious eye disease includes age-related macular degeneration, choroidal neovascularization, retinal neovascularization, and diabetic retinopathy. The transportation of macromolecules like aptamers, recombinant proteins, and monoclonal antibodies to the posterior segment of the eye is challenging due to their high molecular weight, rapid degradation, and low solubility. Moreover, it requires frequent administration for prolonged therapy. The long-acting novel formulation strategies are helpful to overcome these issues and provide superior therapy. It avoids frequent administration, improves stability, high retention time, and avoids burst release. This review briefly enlightens posterior segments of eye diseases with their diagnosis techniques and treatments. This article mainly focuses on recent advanced approaches like intravitreal implants and injectables, electrospun injectables, 3D printed drug-loaded implants, nanostructure thin-film polymer devices encapsulated cell technology-based intravitreal implants, injectable and depots, microneedles, PDS with ranibizumab, polymer nanoparticles, inorganic nanoparticles, hydrogels and microparticles for delivering macromolecules in the eye for intended therapy. Furthermore, novel techniques like aptamer, small Interference RNA, and stem cell therapy were also discussed. It is predicted that these systems will make revolutionary changes in treating posterior segment eye diseases in future.

Therapeutic Ultrasound for Topical Corneal Delivery of Macromolecules

Purpose

The objective of this study was to utilize therapeutic ultrasound in enhancing delivery of topical macromolecules into the cornea.

Methods

Rabbit corneas were dissected and placed in a diffusion cell with a small ultra-red fluorescent protein (smURFP; molecular weight of 32,000 Da) as a macromolecule solution. The corneas were treated with continuous ultrasound application at frequencies of 400 or 600 kHz and intensities of 0.8 to 1.0 W/cm2 for 5 minutes, or sham-treated. Fluorescence imaging of the cornea sections was used to observe the delivery of macromolecules into individual epithelial cells. Spectrophotometric analysis at smURFP maximal absorbance of 640 nm was done to determine the presence of macromolecules in the receiver compartment. Safety of ultrasound application was studied through histology analysis.

Results

Ultrasound-treated corneas showed smURFP delivery into epithelial cells by fluorescence in the cytoplasm, whereas sham-treated corneas lacked any appreciable fluorescence in the individual cells. The sham group showed 0% of subcellular penetration, whereas the 400 kHz ultrasound-treated group and 600 kHz ultrasound-treated group showed 31% and 57% of subcellular penetration, respectively. Spectrophotometry measurements indicated negligible presence of smURFP macromolecules in the receiver compartment solution in both the sham and ultrasound treatment groups, and these macromolecules did not cross the entire depth of the cornea. Histological studies showed no significant corneal damage due to ultrasound application.

Conclusions

Therapeutic ultrasound application was shown to increase the delivery of smURFP macromolecules into the cornea.

Translational Relevance

Our study offers a clinical potential for a minimally invasive macromolecular treatment of corneal diseases.

Therapeutic Effect of Rapamycin-Loaded Small Extracellular Vesicles Derived from Mesenchymal Stem Cells on Experimental Autoimmune Uveitis

Autoimmune uveitis is a major cause of vision loss and glucocorticoids are major traditional medications, which may induce serious complications. Rapamycin has been demonstrated to exhibit immunosuppressive effects and is promising to be used in treating uveitis by intravitreal injection. However, repeated and frequent intravitreal injections increase the risk of severe ocular complications, while the efficacy of subconjunctival injection of rapamycin is low since it is difficult for rapamycin to penetrate eyeball. Recently, small extracellular vesicles (sEVs) have attracted considerable research interest as natural drug delivery systems that can efficiently cross tissues and biological membranes. SEVs derived from mesenchymal stem cells (MSC-sEVs) also can exert immunosuppressive effect and ameliorate experimental autoimmune uveitis (EAU). The aim of this study was to construct a Rapamycin-loaded MSC-sEVs delivery system (Rapa-sEVs) and investigate its therapeutic effect on EAU by subconjunctival injection. Rapa-sEVs were prepared by sonication and characterized by nanoparticle tracking analysis, transmission electron microscopy, and western blotting. Clinical and histological scores were obtained to assess the treatment efficacy. Additionally, T cell infiltration was evaluated by flow cytometry. The results indicated that Rapa-sEVs could reach the retinal foci after subconjunctival injection. Compared to sEVs and rapamycin alone, Rapa-sEVs can produce a more marked therapeutic effect and reduce ocular inflammatory cell infiltration. Overall, MSC-sEVs have significant potential for the delivery of rapamycin to treat EAU. Subconjunctival injection of Rapa-sEVs may be contender for efficacious steroid-sparing immunomodulatory therapy.

Endogenous Endophthalmitis-The Clinical Significance of the Primary Source of Infection

Endophthalmitis is a severe form of ocular inflammation. The source of pathogens in endogenous endophthalmitis is located inside the body, and infection spreads hematogenously. Although rare, endogenous endophthalmitis is a very serious condition, as this type of inflammation is very devastating for ocular tissues. Prognosis is very poor, and the patients are often in a serious general condition, so they require special care and an individual approach in the treatment process. Thanks to the knowledge of the risks associated with infections of individual tissues and organs as well as potential pathogens and the clinical picture, it is possible to make a correct diagnosis faster and implement the correct treatment. In the case of endogenous endophthalmitis, reaction time is absolutely crucial for prognosis. In this review, we focus primarily on the importance of the primary source of infection for the course of the disease and prognosis.

Delivery Strategies for CRISPR/Cas Genome editing tool for Retinal Dystrophies: challenges and opportunities

CRISPR/Cas, an adaptive immune system in bacteria, has been adopted as an efficient and precise tool for site-specific gene editing with potential therapeutic opportunities. It has been explored for a variety of applications, including gene modulation, epigenome editing, diagnosis, mRNA editing, etc. It has found applications in retinal dystrophic conditions including progressive cone and cone-rod dystrophies, congenital stationary night blindness, X-linked juvenile retinoschisis, retinitis pigmentosa, age-related macular degeneration, leber's congenital amaurosis, etc. Most of the therapies for retinal dystrophic conditions work by regressing symptoms instead of reversing the gene mutations. CRISPR/Cas9 through indel could impart beneficial effects in the reversal of gene mutations in dystrophic conditions. Recent research has also consolidated on the approaches of using CRISPR systems for retinal dystrophies but their delivery to the posterior part of the eye is a major concern due to high molecular weight, negative charge, and in vivo stability of CRISPR components. Recently, non-viral vectors have gained interest due to their potential in tissue-specific nucleic acid (miRNA/siRNA/CRISPR) delivery. This review highlights the opportunities of retinal dystrophies management using CRISPR/Cas nanomedicine.

Update on Management of Non-proliferative Diabetic Retinopathy without Diabetic Macular Edema; Is There a Paradigm Shift?

Diabetic retinopathy (DR) is the major cause of visual impairment and blindness in the working-age population. Conventional management for nonproliferative diabetic retinopathy (NPDR) without diabetic macular edema (DME) is derived from the findings of the Early Treatment Diabetic Retinopathy Study (ETDRS). Although the ETDRS protocol basically includes observation, selected cases of severe NPDR may undergo scatter laser photocoagulation. Post-hoc analysis of recent trials has shown that patients with NPDR receiving intravitreal anti-vascular endothelial growth factor (anti-VEGF) for DME would experience improvement in the DR severity scale (DRSS). In addition, recent randomized trials (PANORAMA and Protocol W) have revealed that early intervention with intravitreal aflibercept in eyes with moderately severe to severe NPDR is associated with significant improvement in DRSS and reduced vision-threatening complications of DR. Based on recent studies, it seems that the therapeutic approach to NPDR may undergo a substantial change and a paradigm shift toward considering early intervention with the administration of intravitreal anti-VEGF injections. However, the long-term results and the duration of adherence to anti-VEGF therapy for eyes with NPDR are not yet defined. It is also not apparent whether improvement in DRSS is a true disease modification. Studies showed that DRSS improvement is not associated with retinal reperfusion. In addition, DRCR.net Protocol W showed no visual acuity benefit with the early intravitreal aflibercept injection in moderate to severe NPDR as compared with performing observation plus intravitreal aflibercept applied only after progression to proliferative DR or vision-impairing DME. The cost-benefit ratio is also a challenge. Herein, we look at different aspects of early anti-VEGF application and discuss its pros and cons in the process of treating NPDR.

Feasibility of Therapeutic Ultrasound Application in Topical Scleral Delivery of Avastin

Purpose

Macromolecules have been shown to be effective in vision-saving treatments for various ocular diseases, such as age-related macular degeneration and diabetic retinopathy. The current delivery of macromolecules requires frequent intraocular injections and carries a risk of serious adverse effects.

Methods

We tested the application of therapeutic ultrasound as a minimally invasive approach for the delivery of Avastin into the diseased regions of the eye. Avastin (bevacizumab) is an anti-vascular endothelial growth factor (VEGF) antibody with a molecular weight of 149 kDa. We tested the effectiveness and safety of Avastin delivery through rabbit sclera in vitro using a standard diffusion cell model. Ultrasound at frequencies of 400 kHz or 3 MHz with an intensity of 1 W/cm2 was applied for the first 5 minutes of 1-hour drug exposure. Sham treatments mimicked the ultrasound treatments, but ultrasound was not turned on. Absorbance measurements of the receiver compartment solution were performed at 280 nm using a spectrophotometer.

Results

Absorbance measurements indicated no statistical difference between the sham (n = 13) and 400 kHz ultrasound group (n = 15) in the delivery of Avastin through the sclera. However, the absorbance values were statistically different (P < 0.01) between the 3 MHz ultrasound group (0.004, n = 8) and the matched sham group (0.002, n = 7). There was 2.3 times increase in drug delivery in the 3 MHz ultrasound when compared to the corresponding sham group. Histological studies indicated no significant damage in the ultrasound-treated sclera due to ultrasound application.

Conclusions

Our preliminary results provided support that therapeutic ultrasound may be effective in the delivery of Avastin through the sclera.

Translational Relevance

Our study offers clinical potential for a minimally invasive retinopathy treatment.

Short-term Safety Evaluation of Resident-performed Intravitreal Injection

Purpose: This study evaluated the short-term safety of resident-performed intravitreal injections.Methods: We retrospectively reviewed the medical records of 503 patients (503 eyes) treated for the first time in our hospital from January 2018 to October 2020 via intravitreal bevacizumab, ranibizumab, aflibercept, or triamcinolone acetonide injections by residents or retina specialists. In terms of short-term ophthalmic complications, patients were followed-up 1 day, 1 week, and 1 month after injection.Results: A total of 503 eyes of 503 patients were included. Intravitreal injections were given to 211 and 292 eyes by residents (the resident group) and retina specialists (the retina specialist group), respectively. There were no between-group differences in baseline characteristics except in terms of the indications for injection. Intraocular pressure elevation >5 mmHg occurred in two eyes (0.95%) in the resident group and five (1.71%) in the retina specialist group, but the difference was not statistically significant. Subconjunctival hemorrhage occurred in 29 eyes (13.74%) of the resident group and 32 eyes (10.96%) of the retina specialist group; again, the difference was not statistically significant. No case of noninfectious endophthalmitis occurred in the resident group but two (0.68%) cases occurred in the retina specialist group; again, the difference was not significant. There were two (0.95%) cases of infectious endophthalmitis in the resident group and one (0.34%) case in the retina specialist group; again, the difference was not significant. No corneal erosion, traumatic lens damage, vitreous hemorrhage, or retinal tearing or detachment were noted in either group.Conclusions: Resident-performed intravitreal injections appear to be safe.

Risk of Posterior Capsular Rupture during Phacoemulsification in Patients with the History of Anti-VEGF Intravitreal Injections: Results from the Pan-American Collaborative Retina Study (PACORES) Group

Purpose

To assess the risk for capsular rupture during routine phacoemulsification in patients with a history of anti-VEGF injections and other possible risk modifiers such as treatment patterns, type of anti-VEGF agent, and experience of the surgeon, among others.

Methods

This study reviewed the medical records of 11,129 patients from 7 different hospitals in 5 countries. The study included 939 patients that underwent routine phacoemulsification and had a history of anti-VEGF therapy. We excluded patients with known risk factors for capsular rupture, as well as patients with a history of other retinal procedures. The study extracted data regarding general demographics, the number of previous injections, type of anti-VEGF agent, details of cataract surgery, and anti-VEGF treatment patterns.

Results

Overall prevalence of posterior capsular rupture: 7.45% (95% CI: 5.9–9.32%). The mean number of injections per patient was 3.37 ± 2.8. More than 50% of the patients received their last anti-VEGF injection within three months before cataract surgery. The complication rate during intravitreal injections was 1.07%. In the univariate analysis, the experience of the cataract surgeon (inexperience surgeons; OR: 2.93) and the history of prior anti-VEGF therapy (OR: 1.77) were significant risk indicators for PCR (p < 0.05). However, after controlling for age in the multivariate analysis, the trend did not reach a statistical significance.

Conclusion

The risk for capsular rupture is higher in patients with a history of intravitreal anti-VEGF injections.

Recent Advances in Hydrogels: Ophthalmic Applications in Cell Delivery, Vitreous Substitutes, and Ocular Adhesives

With the prevalence of eye diseases, such as cataracts, retinal degenerative diseases, and glaucoma, different treatments including lens replacement, vitrectomy, and stem cell transplantation have been developed; however, they are not without their respective shortcomings. For example, current methods to seal corneal incisions induced by cataract surgery, such as suturing and stromal hydration, are less than ideal due to the potential for surgically induced astigmatism or wound leakage. Vitrectomy performed on patients with diabetic retinopathy requires an artificial vitreous substitute, with current offerings having many shortcomings such as retinal toxicity. The use of stem cells has also been investigated in retinal degenerative diseases; however, an optimal delivery system is required for successful transplantation. The incorporation of hydrogels into ocular therapy has been a critical focus in overcoming the limitations of current treatments. Previous reviews have extensively documented the use of hydrogels in drug delivery; thus, the goal of this review is to discuss recent advances in hydrogel technology in surgical applications, including dendrimer and gelatin-based hydrogels for ocular adhesives and a variety of different polymers for vitreous substitutes, as well as recent advances in hydrogel-based retinal pigment epithelium (RPE) and retinal progenitor cell (RPC) delivery to the retina.

Posterior cyclodialysis cleft following intravitreal injection

Purpose

To describe an unusual complication of an intravitreal injection.

Observation

Here, we report a case of hypotony following an intravitreal injection due to a posterior cyclodialysis cleft and describe its management and resolution.

Conclusions

Posterior cyclodialysis clefts are a rare cause of hypotony following intravitreal injection. Posterior clefts may not be visualized by conventional gonioscopy. Ultrasound biomicroscopy may be useful in aiding diagnosis.

Importance

This report highlights a rare cause of hypotony following intravitreal injection and illustrates the importance of adjunctive imaging for accurate diagnosis.

Ophthalmic Magnetic Resonance Imaging: Where Are We (Heading To)?

Magnetic resonance imaging of the eye and orbit (MReye) is a cross-domain research field, combining (bio)physics, (bio)engineering, physiology, data sciences and ophthalmology. A growing number of reports document technical innovations of MReye and promote their application in preclinical research and clinical science. Realizing the progress and promises, this review outlines current trends in MReye. Examples of MReye strategies and their clinical relevance are demonstrated. Frontier applications in ocular oncology, refractive surgery, ocular muscle disorders and orbital inflammation are presented and their implications for explorations into ophthalmic diseases are provided. Substantial progress in anatomically detailed, high-spatial resolution MReye of the eye, orbit and optic nerve is demonstrated. Recent developments in MReye of ocular tumors are explored, and its value for personalized eye models derived from machine learning in the treatment planning of uveal melanoma and evaluation of retinoblastoma is highlighted. The potential of MReye for monitoring drug distribution and for improving treatment management and the assessment of individual responses is discussed. To open a window into the eye and into (patho)physiological processes that in the past have been largely inaccessible, advances in MReye at ultrahigh magnetic field strengths are discussed. A concluding section ventures a glance beyond the horizon and explores future directions of MReye across multiple scales, including in vivo electrolyte mapping of sodium and other nuclei. This review underscores the need for the (bio)medical imaging and ophthalmic communities to expand efforts to find solutions to the remaining unsolved problems and technical obstacles of MReye, with the objective to transfer methodological advancements driven by MR physics into genuine clinical value.

Non-pharmacological complications associated with Intravitreal dexamethasone implant injection

OBJECTIVE

Intravitreal dexamethasone implant (IID) is an effective and safe treatment for macular oedema as described in the literature. Ocular hypertension and cataracts are the most frequent complications. The indications of IID in the last few years have led to the retrospective reporting of rare complications, with potential visual impact related to the injection procedure.

METHODS

A case series is presented of fifteen patients treated with IID for macular oedema who developed non-pharmacological complications related to the injection procedure or the implant itself, including, among others anterior chamber migration, intracrystalline injection, endophthalmitis, or segmentation. Differentiation was made between true complications and those that did not lead to any ocular damage. Epidemiological and baseline data were collected along with the treatment and outcome in each case. An analysis was made of multimodal imaging available.

RESULTS

The incidence of complications was 0.65% in this series Anterior chamber migration was the most frequent complication (n=4), followed by intracrystalline injection, and endophthalmitis (n=2). The times between the injection and complications were variable. Visual impairment was the most common symptom (n=6). However, despite the complications found, IID was an effective treatment in most of the reported cases.

CONCLUSIONS

Clinicians should be aware of these rare non-pharmacological complications so that they may be prevented and detected early, avoiding irreversible ocular damage.

Assessment of single nucleotide polymorphisms associated with steroid-induced ocular hypertension

AIM

To access the association of forty-eight single nucleotide polymorphisms (SNPs) identified from Caucasian population with steroid-induced ocular hypertension (OHT) in India population.

METHODS

Fifty-four triamcinolone-acetonide (TA) and forty-seven dexamethasone (Dex) administered subjects were enrolled in the study after a written consent. Intraocular pressure (IOP) values were recorded for a period of 6-month post steroid injections and patients were grouped as steroid-responders (SR: IOP≥21 mm Hg) and non-responders (NR: IOP≤20 mm Hg). Genomic DNA was isolated from peripheral venous blood. Forty-eight SNPs identified in TA treated Caucasian patients by genome wide association study (GWAS) were genotyped using iPLEX™ MassARRAY among TA as well as Dex administered Indian patients. Genotyping data of 48 general subjects from a previous study were considered as reference controls for statistical analysis. Genotypic frequencies were calculated and P-value, Chi-square and odds ratio at 95% confidence-interval of group A (steroid treated vs controls), group B (SR vs NR), group C (phenotype correlation: influence of time, severity and gender on IOP rise), were calculated. P<0.05 was considered to be statistically significant.

RESULTS

OHT was observed in 50% of TA and 26% of Dex administered patients, respectively. IOP rise was mostly severe (>30 mm Hg) and immediate (<1wk) among TA-SR patients while it was noticed to be mild (<30 mm Hg) and between 1-2mo among Dex-SR patients. Logistic regression for risk factor correlation with OHT remained non-significant, hence these factors were not considered as confounding parameters for further analysis. rs133, rs34016742, rs274554, rs10936746, rs274547, rs804854, rs7751500, rs359498, and rs7547448 SNPs significantly varied even after Bonferroni corrections (P<0.0025; group A). rs1879370 (TA) and rs6559662 (Dex) were significantly (P<0.05) associated with OHT (group B). rs133 (severe IOP rise), rs11047639 and rs1879370 (male gender), and rs11171569 (immediate IOP rise) significantly (P<0.05) influenced the phenotype correlation only among TA-OHT patients. However, the significance of these SNPs in group B and phenotype analysis (group C) was lost upon Bonferroni corrections (P<0.0025).

CONCLUSION

Prevalence of OHT in study population is observed to be similar to other studies both in TA and Dex treated patients. We can correlate rs34016742 involved in diabetes signaling pathway to the occurrence of ocular edematous and inflammatory conditions. Except rs133 that is involved in neuro-degeneration and myopia occurrence, none of the other SNPs identified in Caucasian population possess any correlation with OHT incidence in TA and Dex administered Indian subjects.

High Density Display of an Anti-Angiogenic Peptide on Micelle Surfaces Enhances Their Inhibition of αvβ3 Integrin-Mediated Neovascularization In Vitro

Diabetic retinopathy (DR), Retinopathy of Pre-maturity (ROP), and Age-related Macular Degeneration (AMD) are multifactorial manifestations associated with abnormal growth of blood vessels in the retina. These three diseases account for 5% of the total blindness and vision impairment in the US alone. The current treatment options involve heavily invasive techniques such as frequent intravitreal administration of anti-VEGF (vascular endothelial growth factor) antibodies, which pose serious risks of endophthalmitis, retinal detachment and a multitude of adverse effects stemming from the diverse physiological processes that involve VEGF. To overcome these limitations, this current study utilizes a micellar delivery vehicle (MC) decorated with an anti-angiogenic peptide (aANGP) that inhibits αvβ3 mediated neovascularization using primary endothelial cells (HUVEC). Stable incorporation of the peptide into the micelles (aANGP-MCs) for high valency surface display was achieved with a lipidated peptide construct. After 24 h of treatment, aANGP-MCs showed significantly higher inhibition of proliferation and migration compared to free from aANGP peptide. A tube formation assay clearly demonstrated a dose-dependent angiogenic inhibitory effect of aANGP-MCs with a maximum inhibition at 4 μg/mL, a 1000-fold lower concentration than that required for free from aANGP to display a biological effect. These results demonstrate valency-dependent enhancement in the therapeutic efficacy of a bioactive peptide following conjugation to nanoparticle surfaces and present a possible treatment alternative to anti-VEGF antibody therapy with decreased side effects and more versatile options for controlled delivery.

Anisotropic poly(lactic-co-glycolic acid) microparticles enable sustained release of a peptide for long-term inhibition of ocular neovascularization

Leading causes of vision loss include neovascular age-related macular degeneration (NVAMD) and macular edema (ME), which both require frequent intravitreal injections for treatment. A safe, poly(lactic-co-glycolic acid) (PLGA)-based biodegradable polymeric microparticle (MP) delivery system was developed that encapsulates and protects a biomimetic peptide from degradation, allows sustained intraocular release through polymer hydrolysis, and demonstrates a prolonged anti-angiogenic effect in vivo in three different NVAMD animal models (a laser-induced choroidal neovascularization mouse model, a rhoVEGF transgenic mouse model, and a Tet/opsin/VEGF transgenic mouse model) following intravitreal administration. The role of copolymer composition and microparticle shape was explored and 85:15 lactide-to-glycolide PLGA formed into ellipsoidal microparticles was found to be effective at inhibiting neovascularization for at least 16 weeks in vivo. Treatments were found to not only inhibit the growth of neovascularization, but also to cause regression of the neovasculature, reduce vascular leakage, and prevent exudative retinal detachment. These particulate devices are promising for the sustained release of biologics in the eye and may be useful for treating retinal diseases. STATEMENT OF SIGNIFICANCE: Devastating retinal diseases cause blindness in millions of people around the world. Current protein-based treatments have insufficient efficacy for many patients and also necessitate frequent intravitreal injections. Here, we demonstrate a new treatment consisting of a peptide encapsulated in biodegradable microparticles. We explore the effects of copolymer composition and physical shape of polymeric microparticles and find that both modulate peptide release. Efficacy of the treatment was validated in three different mouse models and the lead formulation was determined to be effective long-term, for at least 16 weeks in vivo, following a single injection. Treatments inhibited and regressed neovascularization as well as reduced vascular leakage. Anisotropic polymeric microparticles are promising for the sustained release of biologics in the eye.

A more efficient ocular delivery system of triamcinolone acetonide as eye drop to the posterior segment of the eye

As a leading cause of vision impairment of the retina, macular edema (ME) has one of the highest clinical demands for treatment. Current treatment of ME relies heavily on invasive techniques resulting in complications and poor patient compliance. To enhance the efficiency of triamcinolone acetonide as eye drop to the posterior segment of the eye, we developed and characterized a novel formulation, namely, triamcinolone acetonide chitosan-coated liposomes (TA-CHL), prepared by the calcium acetate gradient method with some modifications. TA-CHL provided the mean particle size of 135.46 ± 4.49 nm and high entrapment efficiency (90.66 ± 3.21%), exhibited a sustained release profile, excellent physical stability, and no significant toxicity on cornea, conjunctiva, and retina. Optical coherence tomography system (OCT) was used to detect pharmacokinetics of CHL in vivo, indicating that CHL had good potency for drug delivery. Cellular uptake experiments showed CHL had the higher transduction efficiency into HCEC and ARPE-19 than liposomes. TA-CHL was shown to be potentially effective eye drop to contribute to the posterior segment of the eye.

Molecular-Physiological Aspects of Regulatory Effect of Peptide Retinoprotectors

Retinal diseases were always difficult problem for clinical ophthalmology. Modern methods of their treatment only decrease risk of complications, however in Russia was created better technology for this purpose: peptide bioregulators, which were made by sequential adding of amino acids one to another, binding with the promoter region of genes, and promoting retinoprotective effect by regulation of their expression, improving the state of the retina.

Novel Random Triblock Copolymers for Sustained Delivery of Macromolecules for the Treatment of Ocular Diseases

The objective of this study is to design, develop, and synthesize novel random triblock (RTB) copolymers for sustained delivery of macromolecules. RTB copolymers have not been utilized for the delivery of macromolecules for ocular diseases. RTB copolymers comprising of polyethylene glycol, glycolide, and ɛ-caprolactone blocks were synthesized and assessed for their molecular weights and purity using ¹H-NMR spectroscopy, gel permeation chromatography, FTIR (functionality), and XRD (crystallinity). No toxicity was observed when ocular cell lines were treated with RTB copolymers. These materials were applied for encapsulation of peptides and proteins (catalase, IgG, BSA, IgG Fab fragment, lysozyme, insulin, and octreotide) in nanoparticles. Particle size ranged from 202.41 ± 2.45 to 300.1 ± 3.11 nm depending on the molecular size and geometry of proteins/peptides. Polydispersity indices were between 0.26 ± 0.02 and 0.46 ± 0.07 respectively. Percentage entrapment efficiency and drug loading ranged from 83.44 ± 2.24 to 45.35 ± 5.53 and 21.56 ± 0.46 to 13.08 ± 1.35 respectively depending on molecular weights of peptides or proteins. A sustained in vitro release of macromolecule was observed over 3-month period. These results suggest that RTB copolymers may be suitable for sustained delivery systems for various macromolecules for different diseases including ocular diseases.

Objective evaluation of lens clarity after the intravitreal injection of sustained-release dexamethasone implant

PURPOSE

To evaluate the lens densitometry values in eyes with macular edema secondary to retinal vein occlusion that were treated with intravitreal dexamethasone implants and to compare these data with those of fellow healthy control eyes.

SETTING

Ulucanlar Eye Training and Research Hospital, Ankara, Turkey.

DESIGN

Prospective case series.

METHODS

Patients with unilateral macular edema secondary to retinal vein occlusion who were to be treated with intravitreal dexamethasone implants were recruited. The lens densitometry values measured with Scheimpflug imaging before and 3 months after the injection were compared with those in fellow healthy eyes.

RESULTS

Thirty-seven patients (22 with branch retinal vein occlusion and 15 with central retinal vein occlusion) with a mean age of 61.5 years ± 11.4 (SD) (range 37 to 82 years) were included. The mean lens densitometry value at Pentacam densitometry zone 1 was significantly increased in the study eyes at 3 months compared with baseline values (baseline 9.44 ± 0.99; 3 months 9.68 ± 1.24; P = .015). At zones 2 and 3, the mean and maximum lens densitometry values in study eyes and lens thickness were similar at baseline and 3 months after injection (P > .05). The densitometry values in fellow healthy eyes were also similar at baseline and at 3 months.

CONCLUSION

The mean lens densitometry value at zone 1 significantly increased from baseline in the study eyes 3 months after the injection of the dexamethasone implant for the treatment of macular edema secondary to retinal vein occlusion.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Noninfectious Inflammatory Response following Intravitreal Bevacizumab Injections: Description of a Cluster of Cases in Two Centers and a Review of the Literature

PURPOSE

To report a cluster of high incidence of noninfectious inflammatory reaction shortly after bevacizumab injection.

METHODS

Data were collected from medical records of consecutive patients who underwent bevacizumab injections and presented with acute uveitis within 1-4 days.

RESULTS

All 7 patients were injected intravitreally with bevacizumab from different batches and presented with visual deterioration. One patient with anterior uveitis complained of pain. None had hypopyon. Three patients with vitritis underwent a vitreous tap with an intravitreal injection of vancomycin and ceftazidime for possible infectious endophthalmitis. All patients received intensive topical antibiotic drops and steroids, and the intraocular inflammation resolved completely within 1 month. Five patients continued to receive bevacizumab injections without recurrent episodes.

CONCLUSIONS

Our series demonstrates an incidence of noninfectious inflammatory reaction shortly after bevacizumab injection that is higher than that reported in the literature. The cause is more likely the preparation process in the same compounding pharmacy.

Intravitreal Injection of Anti-vascular Endothelial Growth Factor Agents for Ocular Vascular Diseases: Clinical Practice Guideline

PURPOSE

To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy.

METHODS

Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations.

RESULTS

All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases.

CONCLUSION

The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients.

Intravitreal Aflibercept for Diabetic Macular Edema: 148-Week Results from the VISTA and VIVID Studies

PURPOSE

To compare efficacy and safety of intravitreal aflibercept injection (IAI) with macular laser photocoagulation for diabetic macular edema (DME) over 3 years.

DESIGN

Two similarly designed phase 3 trials: VISTA^DME and VIVID^DME.

PARTICIPANTS

Patients (eyes; n = 872) with central-involved DME.

METHODS

Eyes received IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser control. From week 24, if rescue treatment criteria were met, IAI patients received active laser, and laser control patients received IAI 2q8. From week 100, laser control patients who had not received IAI rescue treatment received IAI as needed per retreatment criteria.

MAIN OUTCOME MEASURES

The primary end point was the change from baseline in best-corrected visual acuity (BCVA) at week 52. We report the 148-week results.

RESULTS

Mean BCVA gain from baseline to week 148 with IAI 2q4, IAI 2q8, and laser control was 10.4, 10.5, and 1.4 letters (P < 0.0001) in VISTA and 10.3, 11.7, and 1.6 letters (P < 0.0001) in VIVID, respectively. The proportion of eyes that gained ≥15 letters from baseline at week 148 was 42.9%, 35.8%, and 13.6% (P < 0.0001) in VISTA and 41.2%, 42.2%, and 18.9% (P < 0.0001) in VIVID, respectively. Greater proportions of eyes treated with IAI 2q4 and IAI 2q8 versus those treated with laser control had an improvement of ≥2 steps in the Diabetic Retinopathy Severity Scale (DRSS) score in both VISTA (29.9% and 34.4% vs. 20.1% [P = 0.0350, IAI 2q4; P = 0.0052, IAI 2q8]) and VIVID (44.3% and 47.8% vs. 17.4% [P < 0.0001 for both]). In an integrated safety analysis, the most frequent ocular serious adverse event was cataract (3.1%, 2.1%, 0.3% for 2q4, 2q8, and control).

CONCLUSIONS

Visual improvements observed with both IAI regimens (over laser control) at weeks 52 and 100 were maintained at week 148, with similar overall efficacy in the IAI 2q4 and IAI 2q8 groups. Treatment with IAI also had positive effects on the DRSS score. Over 148 weeks, the incidence of adverse events was consistent with the known safety profile of IAI.

The early effects of intravitreal anti vascular endothelial growth factor agents on intraocular pressure and central corneal thickness

To investigate the early effects of two intravitreal (IV) anti vascular endothelial growth factor agents (anti-VEGF), bevacizumab and ranibizumab, on intraocular pressure (IOP) and central corneal thickness (CCT) within the first post-injection month. This prospective study comprised 109 eyes of 109 adult cases who had IV bevacizumab or ranibizumab injections because of age-related macular degeneration (ARMD), retinal venous occlusion (RVO), diabetic retinopathy, and macular edema or central serous chorioretinopathy (CSCR). None of the cases had medical histories of any kinds of glaucoma or increased IOP and IV injection before and all of them underwent a detailed ocular examination including measurements of IOP by non-contact tonometer and CCT by ultrasonic pachymeter pre-injection. IOP measurements were repeated at 30 min and 1st, 7th, and 30th day after the injection. CCT measurements were repeated at the 7th and 30th post-injection day. Paired sample t tests were used for the statistical analysis in order to evaluate the significance of changes in IOP and CCT. The mean age of 56 male and 53 female cases was 63.58 ± 11.04 years. Fifty-six cases (51.4 %) had diabetic retinopathy, 33 cases (30.3 %) had ARMD, 11 cases (10.1 %) had RVO, and 9 cases (8.3 %) had CSCR. Bevacizumab was used in 97 (89 %) cases and ranibizumab was used in 12 (11 %) cases. The IOP increased significantly 30 min after the injection (p < 0.001) but significant decreases were observed at the 1st, 7th, and 30th day post-injection (p < 0.001). No significant differences were observed in CCT between pre-injection and 7th and 30th post-injection day values (p = 0.924 and p = 0.589, respectively). Intravitreal bevacizumab and ranibizumab injections can cause hyper acute increase in IOP because of vitreal expansion but this effect is generally reversible in non-glaucomatous cases.

Neuroinflammatory responses in diabetic retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes and has been recognized as a vascular dysfunction leading to blindness in working-age adults. It becomes increasingly clear that neural cells in retina play an important role in the pathogenesis of DR. Neural retina located at the back of the eye is part of the brain and a representative of the central nervous system. The neurosensory deficits seen in DR are related to inflammation and occur prior to the clinically identifiable vascular complications. The neural deficits are associated with abnormal reactions of retina glial cells and neurons in response to hyperglycemia. Improper activation of the innate immune system may also be an important contributor to the pathophysiology of DR. Therefore, DR manifests characteristics of both vasculopathy and chronic neuroinflammatory diseases. In this article, we attempt to provide an overview of the current understanding of inflammation in neural retina abnormalities in diabetes. Inhibition of neuroinflammation may represent a novel therapeutic strategy to the prevention of the progression of DR.

Intravitreal Aflibercept for Diabetic Macular Edema: 100-Week Results From the VISTA and VIVID Studies

PURPOSE

To compare efficacy and safety of 2 dosing regimens of intravitreal aflibercept injection (IAI) with macular laser photocoagulation for diabetic macular edema (DME).

DESIGN

Two similarly designed, randomized, phase 3 trials, VISTA(DME) and VIVID(DME).

PARTICIPANTS

Patients (eyes; n=872) with type 1 or 2 diabetes mellitus who had DME with central involvement.

METHODS

Eyes received IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser control.

MAIN OUTCOME MEASURES

The primary end point was mean change from baseline in best-corrected visual acuity (BCVA) at week 52. This report presents the 100-week results including mean change from baseline in BCVA, proportion of eyes that gained ≥15 letters, and proportion of eyes with a ≥2-step improvement in the Diabetic Retinopathy Severity Scale (DRSS) score.

RESULTS

Mean BCVA gain from baseline to week 100 with IAI 2q4, IAI 2q8, and laser control was 11.5, 11.1, and 0.9 letters (P < 0.0001) in VISTA and 11.4, 9.4, and 0.7 letters (P < 0.0001) in VIVID, respectively. The proportion of eyes that gained ≥15 letters from baseline at week 100 was 38.3%, 33.1%, and 13.0% (P < 0.0001) in VISTA and 38.2%, 31.1%, and 12.1% (P ≤ 0.0001) in VIVID. The proportion of eyes that lost ≥15 letters at week 100 was 3.2%, 0.7%, and 9.7% (P ≤ 0.0220) in VISTA and 2.2%, 1.5%, and 12.9% (P ≤ 0.0008) in VIVID. Significantly more eyes in the IAI 2q4 and 2q8 groups versus those in the laser control group had a ≥2 step improvement in the DRSS score in both VISTA (37.0% and 37.1% vs. 15.6%; P < 0.0001) and VIVID (29.3% and 32.6% vs. 8.2%; P ≤ 0.0004). In an integrated safety analysis, the most frequent serious ocular adverse event was cataract (2.4%, 1.0%, and 0.3% for 2q4, 2q8, and control).

CONCLUSIONS

In both VISTA and VIVID, the 52-week visual and anatomic superiority of IAI over laser control was sustained through week 100, with similar efficacy in the 2q4 and 2q8 groups. Safety in these studies was consistent with the known safety profile of IAI.

Protective effect of a Chinese Medicine formula He-Ying-Qing-Re Formula on diabetic retinopathy

ETHNOPHARMACOLOGY RELEVANCE

He-Ying-Qing-Re Formula (HF) is a formula modified from "Si-Miao-Yong-An Decoction", a traditional Chinese medical classic emerged in the Qing dynasty and has been reported for treatment of vascular diseases. HF, containing 8 herbs, has been used in local hospital for decades as a complementary method for diabetic retinopathy (DR) with retinal vascular dysfunction. Clinical reports revealed HF could ameliorate vision defects, microaneurysms, hemorrhages and macular edema. The aim of this study is to investigate the anti-DR action of HF and its underlying mechanism experimentally.

METHODS

Chromatographic fingerprinting of HF and rodent model of DR were established; hypoglycemic effect of HF was measured by fasting, random blood glucose and glucose tolerance test; vascular degeneration was measured by retinal digestion; blood-retina-barrier (BRB) permeability was assessed with Evans Blue leakage assay. Advanced glycation end products (AGEs) were measured in vitro and in vivo level; Migration of retinal vascular endothelial cells were determined by wound healing and transwell chamber assays; permeability of endothelial monolayer was monitored with dextran transport. AGEs-related proteins and signaling were measured with immunoblotting and immunohistochemistry.

RESULTS

Chlorogenic acid, ferulic acid and arctin were identified as major components in HF; HF suppresses retinal vasculature degeneration and BRB permeability damage without significant inhibition on hyperglycemia; HF reduces in vitro and in vivo formation of AGEs and AGEs-induced migration as well as permeability of retinal vascular endothelial cells. Expression of tight junction proteins Zo-1 and Claudin-1 was increased while activation of AGEs receptor and downstream signaling Akt were suppressed upon HF treatment.

CONCLUSIONS

HF exhibits protective effect against diabetic retinopathy, which may be associated with inhibition on AGEs and recovery on endothelial dysfunction via modulation of tight junction and AGEs downstream signaling.