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Human retinal organoids (ROs) have emerged as valuable tools for studying retinal development, modeling human retinal diseases, and screening drugs. However, their application is limited primarily due to time-intensive generation, high costs, and low reproducibility. Quality assessment of RO differentiation is crucial for their application in research. However, traditional methods such as morphological evaluation and immunohistochemical analysis have limitations due to their lack of precision and invasiveness, respectively. This study aims to identify non-invasive biomarkers for RO differentiation quality using exosomal microRNAs (miRNAs), which are known to reflect cell-specific functions and development in the retina. We differentiated ROs from human induced pluripotent stem cells (hiPSCs) and classified them into 'superior' and 'inferior' groups based on morphological and immunohistochemical criteria. Exosomes from the conditioned media were isolated and analyzed for miRNA content. Our findings revealed distinct miRNA profiles between superior and inferior ROs, with superior ROs exhibiting higher miRNA diversity and specifically up- or down-regulated miRNAs. Gene ontology and pathway enrichment analyses indicated that the target genes of these miRNAs are involved in neuron proliferation and differentiation. The study suggests the potential of exosomal hsa-miR-654-3p and hsa-miR-451a as non-invasive biomarkers for real-time monitoring of RO quality, facilitating the development of standardized, efficient, and cost-effective culture methods. [ABSTRACT FROM AUTHOR]

X-linked juvenile retinoschisis (XLRS) is a hereditary retinal degeneration affecting young males caused by mutations in the retinoschisin (RS1) gene. We generated human induced pluripotent stem cells (hiPSCs) from XLRS patients and established three-dimensional retinal organoids (ROs) for disease investigation. This disease model recapitulates the characteristics of XLRS, exhibiting defects in RS1 protein production and photoreceptor cell development. XLRS ROs also revealed dysregulation of Na/K-ATPase due to RS1 deficiency and increased ERK signaling pathway activity. Transcriptomic analyses of XLRS ROs showed decreased expression of retinal cells, particularly photoreceptor cells. Furthermore, relevant recovery of the XLRS phenotype was observed when co-cultured with control ROs derived from healthy subject during the early stages of differentiation. In conclusion, our in vitro XLRS RO model presents a valuable tool for elucidating the pathophysiological mechanisms underlying XLRS, offering insights into disease progression. Additionally, this model serves as a robust platform for the development and optimization of targeted therapeutic strategies, potentially improving treatment outcomes for patients with XLRS. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that exosomes are involved in retinal cell degeneration, including their insufficient release; hence, they have become important indicators of retinopathies. The exosomal microRNA (miRNA), in particular, play important roles in regulating ocular and retinal cell functions, including photoreceptor maturation, maintenance, and visual function. Here, we generated retinal organoids (ROs) from human induced pluripotent stem cells that differentiated in a conditioned medium for 60 days, after which exosomes were extracted from ROs (Exo-ROs). Subsequently, we intravitreally injected the Exo-RO solution into the eyes of the Royal College of Surgeons (RCS) rats. Intravitreal Exo-RO administration reduced photoreceptor apoptosis, prevented outer nuclear layer thinning, and preserved visual function in RCS rats. RNA sequencing and miRNA profiling showed that exosomal miRNAs are mainly involved in the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, the expression of MAPK-related genes and proteins was significantly decreased in the Exo-RO-treated group. These results suggest that Exo-ROs may be a potentially novel strategy for delaying retinal degeneration by targeting the MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

Purpose: This retrospective case series aimed to assess the concordance between clinical diagnoses of punctate inner choroidopathy and multifocal choroiditis and panuveitis (MCP) using the 2021 Standardization of Uveitis Nomenclature Working Group criteria., Methods: Using the medical records of the patients, the authors reevaluated 100 eyes of 75 patients with idiopathic multifocal chorioretinal inflammatory lesions based on Standardization of Uveitis Nomenclature criteria and compared the result with the clinical diagnosis., Results: Of 100 eyes, 29 eyes (29%) were diagnosed as punctate inner choroidopathy and 15 eyes (15%) were diagnosed as MCP using Standardization of Uveitis Nomenclature criteria, and 56 (56%) eyes could not be diagnosed as either. Clinically diagnosed punctate inner choroidopathy eyes were significantly more myopic than the clinically diagnosed MCP eyes (mean spherical equivalent -6.65 ± 4.63 vs. -3.85 ± 2.31, P = 0.01). Sixteen eyes with vitreous inflammation were all clinically diagnosed as MCP, but four (25%) could not be diagnosed as MCP using Standardization of Uveitis Nomenclature criteria., Conclusion: The existing diagnostic criteria showed limitations in capturing all clinical cases of punctate inner choroidopathy or MCP, and adding or revising criteria on features such as vitreous inflammation or myopia could be considered to enhance diagnostic accuracy.

Purpose: To evaluate the efficacy of intravitreal brolucizumab in polyp regression of treatment-naive polypoidal choroidal vasculopathy (PCV) patients and its effect on 1-year treatment outcome., Methods: Medical records of 31 treatment-naive PCV patients, who received three monthly intravitreal brolucizumab injections followed by as-needed injections for at least a year, were retrospectively reviewed. Visual and anatomical outcomes were evaluated at 3, 6, and 12 months. Complete polyp regression rate and percentage change of vascular lesion and polyp area were evaluated after three monthly injections of brolucizumab. The effect of complete polyp regression and the impact of vascular lesion and polyp reduction rate on 1-year treatment outcome were also evaluated., Results: In terms of visual outcome, best-corrected visual acuity significantly improved after 12-month follow-up (p < 0.001). In terms of anatomical outcome, central macular thickness (CMT) and central choroidal thickness significantly decreased after 12-month follow-up (p < 0.001). Complete polyp regression was observed in 23 patients (74.2%) after three monthly injections. Group with complete polyp regression had a higher rate of achieving dry macula at 3 months (p = 0.026) and fewer number of injections (p < 0.001) compared to the group without complete polyp regression. Higher polyp reduction rate was significantly associated with higher CMT change from baseline at 3 months (p = 0.048) while higher vascular lesion reduction rate was significantly associated with higher CMT change from baseline at 12 months (p = 0.031) and fewer number of injections (p = 0.012)., Conclusions: Intravitreal brolucizumab injection effectively improved visual and anatomical outcomes and achieved significant polyp regression in treatment-naive PCV patients. Complete polyp regression and the reduction rate of vascular lesion size and polyp size after loading injection significantly influence the treatment outcome of PCV patients. However, careful monitoring and preoperative warning is warranted due to occurrence of brolucizumab-related IOI.