Bi-allelic variants in COQ8B, a gene involved in the biosynthesis of coenzyme Q10, lead to non-syndromic retinitis pigmentosa.

Retinitis pigmentosa (RP) is a Mendelian disease characterized by gradual loss of vision, due to the progressive degeneration of retinal cells. Genetically, it is highly heterogeneous, with pathogenic variants identified in more than 100 genes so far. Following a large-scale sequencing screening, we identified five individuals (four families) with recessive and non-syndromic RP, carrying as well bi-allelic DNA changes in COQ8B, a gene involved in the biosynthesis of coenzyme Q10. Specifically, we detected compound heterozygous assortments of five disease-causing variants (c.187C>T [p.Arg63Trp], c.566G>A [p.Trp189Ter], c.1156G>A [p.Asp386Asn], c.1324G>A [p.Val442Met], and c.1560G>A [p.Trp520Ter]), all segregating with disease according to a recessive pattern of inheritance. Cell-based analysis of recombinant proteins deriving from these genotypes, performed by target engagement assays, showed in all cases a significant decrease in ligand-protein interaction compared to the wild type. Our results indicate that variants in COQ8B lead to recessive non-syndromic RP, possibly by impairing the biosynthesis of coenzyme Q10, a key component of oxidative phosphorylation in the mitochondria.

Streamlined Ophthalmologist-Led Pathway to Diagnosis and Accessibility of Genetics Testing for Patients with Inherited Retinal Dystrophies in Canada.

OBJECTIVE: To investigate the ability of a new clinical model to improve accessibility and expedite the pathway to molecular diagnosis for patients with suspected inherited retinal diseases (IRD). DESIGN: Retrospective cohort study of electronic patient records. PARTICIPANTS: All patients referred to general medical genetic clinic between September 2017 to September 2019 and an ophthalmologist-led IRD clinic between October 2021 to July 2023 for suspected IRD were included. METHODS: The difference in timeliness and accessibility to diagnosis and genetics testing for patients referred for suspected IRDs were compared based on whether they were referred to general medical genetics clinic or an ophthalmologist-led IRD clinic. MAIN OUTCOME MEASURES: The primary outcomes were time to consult from referral; time from initial consult to molecular diagnosis; and the time from initial consult to genetics result disclosure and counseling. Secondary outcomes included number of prior providers investigating the chief complaint; the proportion of patients undergoing genetics testing; and the range of diagnostic investigations undertaken. RESULTS: 473 patients were included, with 212 cases from general medical genetics clinic and 261 from medical retina clinic. The mean time from referral to initial consult was 14 months (±3.33 months) and 4 months (±3.4 months) for general medical genetics and the ophthalmologist-led IRD clinic respectively. The mean time from initial consult to genetics disclosure and counselling was 6 months (±3.6 months) and 3.5 months (±1.8 months) for medical genetics and the ophthalmologist-led model respectively. The total time from initial referral to genetics disclosure and counselling for the medical geneticist-led clinic model was 20-24 months. The total time from initial referral to genetics disclosure and counselling for ophthalmologist-led retinal clinic was 5-8 months. The average number of prior providers seen prior to presenting to ophthalmologist-led retina clinic was 2.05 (range 1-10). CONCLUSIONS: Shifting from the traditional medical genetics model to the new ophthalmologist-led IRD clinical model may improve accessibility and expedite the pathway to molecular diagnosis and subsequent gene therapy trials for patients with suspected IRDs.

Genetic therapies and potential therapeutic applications of CRISPR activators in the eye.

Conventional gene therapy involving supplementation only treats loss-of-function diseases and is limited by viral packaging sizes, precluding therapy of large genes. The discovery of CRISPR/Cas has led to a paradigm shift in the field of genetic therapy, with the promise of precise gene editing, thus broadening the range of diseases that can be treated. The initial uses of CRISPR/Cas have focused mainly on gene editing or silencing of abnormal variants via utilising Cas endonuclease to trigger the target cell endogenous non-homologous end joining. Subsequently, the technology has evolved to modify the Cas enzyme and even its guide RNA, leading to more efficient editing tools in the form of base and prime editing. Further advancements of this CRISPR/Cas technology itself have expanded its functional repertoire from targeted editing to programmable transactivation, shifting the therapeutic focus to precise endogenous gene activation or upregulation with the potential for epigenetic modifications. In vivo experiments using this platform have demonstrated the potential of CRISPR-activators (CRISPRa) to treat various loss-of-function diseases, as well as in regenerative medicine, highlighting their versatility to overcome limitations associated with conventional strategies. This review summarises the molecular mechanisms of CRISPRa platforms, the current applications of this technology in vivo, and discusses potential solutions to translational hurdles for this therapy, with a focus on ophthalmic diseases.

Systematic Literature Reviews Comparing the Long-Term Safety Outcomes for the Port Delivery System with Ranibizumab (PDS) Versus Other Ocular Implants.

OBJECTIVES: To determine whether the types and rates of post-surgical complications associated with the Port Delivery System with ranibizumab (PDS) are comparable with those reported for other ocular implants that cross the sclera. METHODS: Systematic literature reviews were conducted to determine the long-term (≥ 18-month) safety of ocular implants that cross the sclera in clinical trials and real-world studies. Complication types and rates were compared with those reported for the PDS in phase III clinical trials (Archway, Pagoda, and Pavilion). RESULTS: Sixteen clinical trials (24 publications) and 43 real-world studies were identified reporting 30 complications in eyes with 15 implant types and 8 ocular diseases. Implants were associated with an acceptable, well-characterized safety profile, with most complications resolving spontaneously or with treatment. Device-related complications were reported in 0.7% (0.0-5.0%) of study eyes in clinical trials and 1.3% (0.0-14.5%) of eyes in real-world studies. Rates of conjunctival complications were 2.1% (0.0-22.8%) and 2.2% (0.9-4.6%), respectively. The overall types and rates of adverse events of special interest reported for the PDS in phase III trials (cataract, conjunctival bleb, vitreous hemorrhage, conjunctival erosion, conjunctival retraction, endophthalmitis, implant dislocation, retinal detachment, and hyphema) were within the ranges reported for other ocular implants. CONCLUSIONS: The rates of complications reported in phase III clinical trials for the PDS were within the ranges reported for other ocular implants that cross the sclera. This suggests that the long-term safety of the PDS is consistent with other ocular devices established in ophthalmology clinical practice. TRIAL REGISTRATION: PROSPERO international prospective register of systematic reviews: CRD5202234129, CRD42022343129.

Progression rate of macular retinal pigment epithelium atrophy in geographic atrophy and selected inherited retinal dystrophies. A systematic review and meta-analysis.

PURPOSE: To compare the macular retinal pigment epithelium (RPE) atrophy progression rate of selected degenerative and macular inherited retinal diseases (IRD). DESIGN: Systematic review and meta-analysis. METHODS: The protocol was registered on the PROSPERO database. Medline, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar were searched up to 15/Sep/2023 for articles reporting the RPE atrophy growth rate in treatment-naïve eyes with geographic atrophy (GA), Stargardt disease (STGD1), Best disease, pseudoxanthoma elasticum (PXE), central areolar choroidal dystrophy (CACD), or pattern dystrophies with no previous or current macular neovascularization and a minimum follow-up time of 12 months. Meta-analyses determined mean RPE atrophy growth rates per disease, imaging modality (fundus autofluorescence [FAF], optical coherence tomography [OCT], or color fundus photography [CFP]) and metric (mm2/year or mm/year). The Newcastle-Ottawa scale and the Cochrane Risk-of-Bias tool assessed the risk of bias, and funnel plots were used to evaluate small-study effects. RESULTS: From 4354 publications, 85 were included for meta-analysis: 69 studies (7815 eyes) on GA, 15 (1367 eyes) on STGD1, and one on both. Two studies on PXE were only eligible for review. No studies for other diseases met our eligibility criteria. The overall mean RPE atrophy growth rate for GA using FAF was 1.65 mm2/year (95% confidence interval [CI], 1.49-1.81) and 0.35 mm/year (95% CI, 0.28-0.41); using OCT, it was 1.46 mm2/year (95% CI, 1.28-1.64) and 0.34 mm/year (95% CI, 0.28-0.40); and on CFP it was 1.76 mm2/year (95% CI, 1.56-1.97) and 0.30 mm/year (95% CI, 0.28-0.31). For STGD1, using FAF it was 1.0 mm2/year (95% CI, 0.77-1.23) and 0.20 mm/year (95% CI, 0.17-0.23); on OCT, it was 0.80 mm2/year (95% CI, 0.72-0.88). No studies on STGD1 reported the growth rate with other imaging modalities or metrics. Growth rates in GA were faster than in STGD1 (p<0.05). A larger baseline area of atrophy was generally associated with faster growth rates. CONCLUSION: The RPE atrophy growth rate in GA is faster than in STGD1 but with great variation between studies and imaging modalities. Limited information was available for other macular IRD, suggesting further research is needed.

The Formation and Renewal of Photoreceptor Outer Segments.

The visual system is essential for humans to perceive the environment. In the retina, rod and cone photoreceptor neurons are the initial sites where vision forms. The apical region of both cone and rod photoreceptors contains a light-sensing organelle known as the outer segment (OS), which houses tens of thousands of light-sensitive opsins. The OSs of photoreceptors are not static; they require rhythmic renewal to maintain normal physiological functions. Disruptions in OS renewal can lead to various genetic disorders, such as retinitis pigmentosa (RP). Understanding the patterns and molecular mechanisms of photoreceptor OS renewal remains one of the most intriguing topics in visual biology. This review aims to elucidate the structure of photoreceptor OSs, the molecular mechanisms underlying photoreceptor OS renewal, and the retinal diseases resulting from defects in this renewal process. Additionally, we will explore retinal diseases related to photoreceptor OS renewal and potential therapeutic strategies, concluding with a discussion on future research directions for OS renewal.

What's New in Ocular Drug Delivery: Advances in Suprachoroidal Injection since 2023.

Despite significant advancements in ocular drug delivery, challenges persist in treating posterior segment diseases like macular edema (ME) and age-related macular degeneration (AMD). Suprachoroidal (SC) injections are a promising new method for targeted drug delivery to the posterior segment of the eye, providing direct access to the choroid and retina while minimizing systemic exposure and side effects. This review examines the anatomical and physiological foundations of the SC space; evaluates delivery devices such as microcatheters, hypodermic needles, and microneedles; and discusses pharmacokinetic principles. Additionally, advancements in gene delivery through SC injections are explored, emphasizing their potential to transform ocular disease management. This review also highlights clinical applications in treating macular edema, diabetic macular edema, age-related macular degeneration, choroidal melanoma, and glaucoma. Overall, SC injections are emerging as a promising novel route for administering ophthalmic treatments, with high bioavailability, reduced systemic exposure, and favorable safety profiles. Key therapeutic agents such as triamcinolone acetonide, dexamethasone, AAV-based gene therapy, and axitinib have shown promise. The field of suprachoroidal injection is progressing rapidly, and this review article, while attempting to encapsulate most of the published preclinical and clinical studies, mainly focuses on those that are published within 2023 and 2024.

The Framework of Quantifying Biomarkers of OCT and OCTA Images in Retinal Diseases.

Despite the significant advancements facilitated by previous research in introducing a plethora of retinal biomarkers, there is a lack of research addressing the clinical need for quantifying different biomarkers and prioritizing their importance for guiding clinical decision making in the context of retinal diseases. To address this issue, our study introduces a novel framework for quantifying biomarkers derived from optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images in retinal diseases. We extract 452 feature parameters from five feature types, including local binary patterns (LBP) features of OCT and OCTA, capillary and large vessel features, and the foveal avascular zone (FAZ) feature. Leveraging this extensive feature set, we construct a classification model using a statistically relevant p value for feature selection to predict retinal diseases. We obtain a high accuracy of 0.912 and F1-score of 0.906 in the task of disease classification using this framework. We find that OCT and OCTA's LBP features provide a significant contribution of 77.12% to the significance of biomarkers in predicting retinal diseases, suggesting their potential as latent indicators for clinical diagnosis. This study employs a quantitative analysis framework to identify potential biomarkers for retinal diseases in OCT and OCTA images. Our findings suggest that LBP parameters, skewness and kurtosis values of capillary, the maximum, mean, median, and standard deviation of large vessel, as well as the eccentricity, compactness, flatness, and anisotropy index of FAZ, may serve as significant indicators of retinal conditions.

Atypical fundoscopic manifestation with good visual prognosis in familial hypomagnesemia with hypercalciuria and nephrocalcinosis.

PURPOSE: Pathogenic variants in the CLDN19 gene are responsible for Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC) with ocular pathology (MIM *248190). Our objective was to delineate the ophthalmological and genetic manifestations of a patient with FHHNC and a pathogenic variant in CLDN19. CASE REPORT: A 25-year-old woman presented with renal involvement and a best-corrected visual acuity of 20/25 in the right eye and finger-counting ability in the left eye. The patient exhibited high myopia, convergent strabismus, and chorioretinal atrophic plaques in the perifoveal and peripapillary areas. We conducted a comprehensive ophthalmological examination, including refraction, fundoscopy, color and autofluorescence retinography, optical coherence tomography, and electrophysiology tests. Additionally, next-generation sequencing was performed using Illumina NextSeq500. We identified a homozygous missense variant, c.59G>A p.Gly20Asp, in the CLDN19 gene as the cause of renal and ocular manifestations. CONCLUSION: FHHNC is associated with various ocular alterations. The unique retinal disorders described in this article suggest a more favorable visual prognosis compared to those previously reported in the literature. Determining the phenotypic diversity of this disease may aid in the diagnosis and management of future cases.

Cross-sectional Analysis of Outer Retinal Tubulation in Inherited Retinal Diseases: A Multicenter Study.

PURPOSE: This study aims to explore genetic variants that potentially lead to outer retinal tubulation (ORT), estimate the prevalence of ORT in these candidate genes, and investigate the clinical etiology of ORT in patients with inherited retinal diseases (IRDs), with respect to each gene. DESIGN: Retrospective cohort study. METHODS: A retrospective cross-sectional review was conducted on 565 patients with molecular diagnoses of IRD, confirming the presence of ORT as noted in each patient's respective spectral-domain optical coherence tomography (SD-OCT) imaging. Using SD-OCT imaging, the presence of ORT was analyzed in relation to specific genetic variants and phenotypic characteristics. Outcomes included the observed ORT frequencies across two gene-specific cohorts: non- retinal pigment epithelium (RPE)-specific genes, and RPE-specific genes; and to investigate the analogous characteristics caused by variants in these genes. RESULTS: Among the 565 patients included in this study, 104 exhibited ORT on SD-OCT. We observed ORT frequencies among the following genes from our patient cohort: 100% (23/23) forCHM, 100%(2/2) forPNPLA6, 100% (4/4) forRCBTB1, 100% formtDNA[100% (4/4) forMT-TL1and 100% (1/1) formtDNAdeletion], 100% (1/1) forOAT, 95.2% (20/21) forCYP4V2, 72.7% (8/11) forCHMfemale carriers, 66.7% (2/3) forC1QTNF5, 57.1% (8/14) forPROM1, 53.8% (7/13) forPRPH2, 42.9% (3/7) forCERKL, 28.6% (2/7) forCDHR1, 20% (1/5) forRPE65, 4% (18/445) forABCA4.In contrast, ORT was not observed in any patients with photoreceptor-specific gene variants, such asRHO(n=13),USH2A(n=118),EYS(n=70),PDE6B(n=10),PDE6A(n=4),and others. CONCLUSION: These results illustrate a compelling association between the presence of ORT and IRDs caused by variants in RPE-specific genes, as well as non-RPE-specific genes. In contrast, IRDs caused by photoreceptor-specific genes are typically not associated with ORT occurrence. Further analysis revealed that ORT tends to manifest in IRDs with milder intraretinal pigment migration (IPM), a finding that is typically associated with RPE-specific genes. These findings regarding ORT, genetic factors, atrophic patterns in the fundus, and IPM provide valuable insight into the complex etiology of IRDs. Future prospective studies are needed to further explore the association and underlying mechanisms of ORT in these contexts.

Comprehensive assessment of the impact of intravitreal faricimab on retinal diseases: A systematic review, meta-analysis, and trial sequential analysis.

BACKGROUND: Faricimab stands as the inaugural and sole bispecific antibody approved by the US Food and Drug Administration (FDA) for intravitreal injection. Nonetheless, the efficacy and safety of intravitreal faricimab remained uncertain. OBJECTIVES: The purpose of this study was to evaluate faricimab. METHODS: This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (CRD42023398320). Five databases (Pubmed, Embase, Web of science, Cochrane Library, ClinicalTrials gov) were searched. We calculated pooled standard mean difference or odds ratio with 95 % confident interval under a random-effect model or fixed-effect model. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was employed to ascertain the reliability of the analyses. Trial sequential analysis was performed to gauge the statistical reliability of the data in the cumulative meta-analysis. RESULTS: 8 studies (3975 participants) were included. The use of faricimab was associated with central subfield thickness (CST) change, but no difference was found in other primary efficacy outcomes. Apart from that, a correlation was observed between the use of faricimab and the risk of vitreous floaters. Based on TSA, strong evidence indicates that compared to the control group, faricimab aided in reducing CST but increasing the risk of vitreous floaters. CONCLUSIONS: In this study, a correlation existed between the use of faricimab and a reduction in CST, indicating a superior therapeutic effect. Moreover, participants treated with faricimab demonstrated a higher risk of vitreous floaters. More randomized controlled trials are essential to further explore the efficacy and safety of faricimab.

The Landscape of Genomic Services for Inherited Retinal Degenerations (IRDs) Across Europe.

Purpose: To map the existing genomic services available for patients with IRDs across Europe. Methods: A survey was conducted to 24 ophthalmic and/or genetic specialists across 19 European countries. The survey was conducted in an interview style via zoom for participants from 17 out of 19 countries. Interviewees were clinical/medical/ophthalmic geneticists, ophthalmologists/retina specialists and internal medicine specialists. The survey focused on referral pathways, genetic counseling, insurance coverage, awareness of genetic testing and counseling for IRDs among practitioners and patients, and preferred testing methodologies. Results: Genomic services (testing and counselling) for IRDs vary among countries from an awareness, availability and insurance coverage perspective. Affordability could be a barrier for patients in countries without any payment scheme (eg, Poland) and in countries where only a targeted population is covered (eg, Bulgaria). Genetic counseling via qualified genetic counsellors did not exist in many countries. The level of awareness regarding the benefits of genetic testing in IRDs among healthcare professionals (HCPs) and patients was perceived as low in some countries. Panel-based next-generation sequencing (NGS) was the first test of choice for genetic testing in 68% of the studied countries. Conclusion: There is some disparity in the approach to genetic testing for IRDs across Europe. Greater awareness of genetic testing services is required among the eye care professional community. A revised approach to the provision of genetic testing services such as centralized free genetic testing with associated interpretation and genetic counselling may help in ensuring equitable access and reimbursement, which will empower patients through improved access to clinical trials, expedite innovation, improve access to therapy and the delivery of care.

The Immunomodulatory Effect of Silver Nanoparticles in a Retinal Inflammatory Environment.

Activation of immune response plays an important role in the development of retinal diseases. One of the main populations of immune cells contributing to the retinal homeostasis are microglia, which represent a population of residential macrophages. However, under pathological conditions, microglia become activated and rather support a harmful inflammatory reaction and retinal angiogenesis. Therefore, targeting these cells could provide protection against retinal neuroinflammation and neovascularization. In the recent study, we analyzed effects of silver nanoparticles (AgNPs) on microglia in vitro and in vivo. We showed that the AgNPs interact in vitro with stimulated mouse CD45/CD11b positive cells (microglia/macrophages), decrease their secretion of nitric oxide and vascular endothelial growth factor, and regulate the expression of genes for Iba-1 and interleukin-1ß (IL-1ß). In our in vivo experimental mouse model, the intravitreal application of a mixture of proinflammatory cytokines tumor necrosis factor-α, IL-1ß and interferon-γ induced local inflammation and increased local expression of genes for inducible nitric oxide synthase, IL-α, IL-1ß and galectin-3 in the retina. This stimulation of local inflammatory reaction was significantly inhibited by intravitreal administration of AgNPs. The application of AgNPs also decreased the presence of CD11b/Galectin-3 positive cells in neuroinflammatory retina, but did not influence viability of cells and expression of gene for rhodopsin in the retinal tissue. These data indicate that AgNPs regulate reactivity of activated microglia in the diseased retina and thus could provide a beneficial effect for the treatment of several retinal diseases.

The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications.

PURPOSE: To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans. METHODS: Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D). RESULTS: The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions. CONCLUSION: Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

Optogenetics and Targeted Gene Therapy for Retinal Diseases: Unravelling the Fundamentals, Applications, and Future Perspectives.

With a common aim of restoring physiological function of defective cells, optogenetics and targeted gene therapies have shown great clinical potential and novelty in the branch of personalized medicine and inherited retinal diseases (IRDs). The basis of optogenetics aims to bypass defective photoreceptors by introducing opsins with light-sensing capabilities. In contrast, targeted gene therapies, such as methods based on CRISPR-Cas9 and RNA interference with noncoding RNAs (i.e., microRNA, small interfering RNA, short hairpin RNA), consists of inducing normal gene or protein expression into affected cells. Having partially leveraged the challenges limiting their prompt introduction into the clinical practice (i.e., engineering, cell or tissue delivery capabilities), it is crucial to deepen the fields of knowledge applied to optogenetics and targeted gene therapy. The aim of this in-depth and novel literature review is to explain the fundamentals and applications of optogenetics and targeted gene therapies, while providing decision-making arguments for ophthalmologists. First, we review the biomolecular principles and engineering steps involved in optogenetics and the targeted gene therapies mentioned above by bringing a focus on the specific vectors and molecules for cell signalization. The importance of vector choice and engineering methods are discussed. Second, we summarize the ongoing clinical trials and most recent discoveries for optogenetics and targeted gene therapies for IRDs. Finally, we then discuss the limits and current challenges of each novel therapy. We aim to provide for the first time scientific-based explanations for clinicians to justify the specificity of each therapy for one disease, which can help improve clinical decision-making tasks.

Clinical exome analysis and targeted gene repair of the c.1354dupT variant in iPSC lines from patients with PROM1-related retinopathies exhibiting diverse phenotypes.

BACKGROUND: Inherited retinal dystrophies (IRD) are one of the main causes of incurable blindness worldwide. IRD are caused by mutations in genes that encode essential proteins for the retina, leading to photoreceptor degeneration and loss of visual function. IRD generates an enormous global financial burden due to the lack of understanding of a significant part of its pathophysiology, molecular diagnosis, and the near absence of non-palliative treatment options. Patient-derived induced pluripotent stem cells (iPSC) for IRD seem to be an excellent option for addressing these questions, serving as exceptional tools for in-depth studies of IRD pathophysiology and testing new therapeutic approaches. METHODS: From a cohort of 8 patients with PROM1-related IRD, we identified 3 patients carrying the same variant (c.1354dupT) but expressing three different IRD phenotypes: Cone and rod dystrophy (CORD), Retinitis pigmentosa (RP), and Stargardt disease type 4 (STGD4). These three target patients, along with one healthy relative from each, underwent comprehensive ophthalmic examinations and their genetic panel study was expanded through clinical exome sequencing (CES). Subsequently, non-integrative patient-derived iPSC were generated and fully characterized. Correction of the c.1354dupT mutation was performed using CRISPR/Cas9, and the genetic restoration of the PROM1 gene was confirmed through flow cytometry and western blotting in the patient-derived iPSC lines. RESULTS: CES revealed that 2 target patients with the c.1354dupT mutation presented monoallelic variants in genes associated with the complement system or photoreceptor differentiation and peroxisome biogenesis disorders, respectively. The pluripotency and functionality of the patient-derived iPSC lines were confirmed, and the correction of the target mutation fully restored the capability of encoding Prominin-1 (CD133) in the genetically repaired patient-derived iPSC lines. CONCLUSIONS: The c.1354dupT mutation in the PROM1 gene is associated to three distinct AR phenotypes of IRD. This pleotropic effect might be related to the influence of monoallelic variants in other genes associated with retinal dystrophies. However, further evidence needs to be provided. Future experiments should include gene-edited patient-derived iPSC due to its potential as disease modelling tools to elucidate this matter in question.

Usability of the SB11 Pre-filled Syringe (PFS) in Patients with Retinal Diseases.

INTRODUCTION: SB11 (Byooviz™; Samsung Bioepis Co., Ltd.) is a ranibizumab (Lucentis®; Genentech, Inc.) biosimilar targeting vascular endothelial growth factor A for the treatment of retinal diseases. The pre-filled syringe (PFS) presentation of SB11 offers an alternative administration method to the vial, with the potential for enhanced safety and efficient syringe preparation. The objective of this study was to assess the ability of healthcare professionals (HCPs) to follow the instructions for use to prepare and administer SB11 PFS intravitreal (IVT) injections to patients with neovascular age-related macular degeneration (nAMD) or macular edema secondary to retinal vein occlusion (RVO). METHODS: This study was an open-label, single-arm, single-dose clinical study to evaluate the usability of the SB11 PFS in patients with nAMD or macular edema secondary to RVO. Four HCPs prepared and administered 0.5 mg SB11 PFS IVT injections to 34 patients. Product use task completion (12 tasks in total) was assessed by independent observers. Safety was assessed up to 7 days after injection of the investigational product. RESULTS: A total of 34 patients were enrolled and completed the study. All 12 tasks were successfully completed in 34 (100%) patients without a use-related failure. Most patients (32 patients, 94.1%) experienced no adverse events (AEs), whereas 2 (5.9%) patients experienced three treatment-emergent AEs (TEAEs) which were mild to moderate in severity. There were no severe or serious TEAEs reported during the study. CONCLUSIONS: This study showed that HCPs were able to successfully prepare and administer the SB11 PFS via IVT injection. No unexpected safety issues were identified. The SB11 PFS is a promising alternative for therapeutic administration of SB11 in patients with retinal disease. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT06176963; EudraCT number 2021-003566-12.

Genetic Analysis of 252 Index Cases with Inherited Retinal Diseases Using a Panel of 351 Retinal Genes.

Inherited retinal diseases (IRDs) are extremely heterogeneous with at least 350 causative genes, complicating the process of genetic diagnosis. We analyzed samples of 252 index cases with IRDs using the Blueprint Genetics panel for "Retinal Dystrophy" that includes 351 genes. The cause of disease could be identified in 55% of cases. A clear difference was obtained between newly recruited cases (74% solved) and cases that were previously analyzed by panels or whole exome sequencing (26% solved). As for the mode of inheritance, 75% of solved cases were autosomal recessive (AR), 10% were X-linked, 8% were autosomal dominant, and 7% were mitochondrial. Interestingly, in 12% of solved cases, structural variants (SVs) were identified as the cause of disease. The most commonly identified genes were ABCA4, EYS and USH2A, and the most common mutations were MAK-c.1297_1298ins353 and FAM161A-c.1355_1356del. In line with our previous IRD carrier analysis, we identified heterozygous AR mutations that were not the cause of disease in 36% of cases. The studied IRD panel was found to be efficient in gene identification. Some variants were misinterpreted by the pipeline, and therefore, multiple analysis tools are recommended to obtain a more accurate annotation of potential disease-causing variants.

Diffusion of nanoparticles in heterogeneous hydrogels as vitreous humour in vitro substitutes.

Nanomedicine has the potential to increase the biostability of drugs to treat retinal diseases, improving their performance and decreasing the required number of intravitreal injections. However, accurate pharmacokinetic studies of these nanoparticle-drug conjugates, nanoparticle motion across the vitreous humour and interaction with the retinal cell layers still need to be investigated. Existing nanoparticle tracking techniques require fluorescent labels, which can impact cytotoxicity, nanoparticles' motion, protein interactions, and cell internalization. In this study, a real-time label-free tracking technology, for single nanoparticles in an optical microscope based on the optical phenomena of caustics, was used to characterise the diffusion of nanoparticles in agar-hyaluronic acid hydrogels, previously validated as vitreous humour substitutes for in vitro models. The results demonstrated that the diffusion of nanoparticles through these hydrogels was heterogeneous, and that nanoparticle size had an important role in nanoparticle distribution across and within in vitro vitreous substitutes. These findings suggest that nanoparticle diameter is a critical parameter for designing novel therapeutics for retinal diseases. Moreover, nanoparticle charge did not affect nanoparticle diffusion or distribution in these synthetic hydrogels. The use of caustics in optical microscopy has been demonstrated to be a reproducible, inexpensive technique for screening novel therapeutics in eye in vitro models.

Genetic Testing of Patients with Inherited Retinal Diseases in the European Countries: An International Survey by the European Vision Institute.

INTRODUCTION: The purpose of this project was to explore the current standards of clinical care genetic testing and counseling for patients with inherited retinal diseases (IRDs) from the perspective of leading experts in selected European countries. Also, to gather opinions on current bottlenecks and future solutions to improve patient care. METHODS: On the initiative of the European Vision Institute, a survey questionnaire with 41 questions was designed and sent to experts in the field from ten European countries. Each participant was asked to answer with reference to the situation in their own country. RESULTS: Sixteen questionnaires were collected by November 2023. IRD genetic tests are performed in clinical care settings for 80% or more of tested patients in 9 countries, and the costs of genetic tests in clinical care are covered by the public health service to the extent of 90% or more in 8 countries. The median proportion of patients who are genetically tested, the median rate of genetically solved patients among those who are tested, and the median proportion of patients receiving counseling are 51-70%, 61-80%, and 61-80%, respectively. Improving the education of healthcare professionals who facilitate patient referrals to specialized centers, improving access of patients to more thorough genotyping, and increasing the number of available counselors were the most advocated solutions. CONCLUSION: There is a significant proportion of IRD patients who are not genetically tested, whose genetic testing is inconclusive, or who do not receive counseling. Educational programs, greater availability of state-of-the-art genotyping and genetic counselors could improve healthcare for IRD patients.