bluuebunny/crossref_metadata_2025 huggingface dataset:
European reference network for rare eye diseases (ERN‐eye) and paediatric working group
Authors: Noval Susana
Published: January 2025

European Reference Networks (ERNs) are cross‐border networks that unite specialized and reference hospital centers across Europe to treat rare and complex diseases requiring highly specialized healthcare. Currently, there are 24 ERNs across the EU and Norway, established under Directive 2011/24/EU on patients' rights in cross‐border healthcare. ERN‐EYE is the network dedicated to over 900 rare eye diseases, which are the leading cause of visual impairment and blindness in children and young adults in Europe. ERN‐EYE is organized into four working groups (WGs), including WG3 on Paediatric Rare Eye Diseases, and six cross‐cutting working groups, including WG6 on Genetic Diagnosis. The paediatric group is highly active and involved in developing Good Clinical Practice Guidelines, exchanging views on difficult cases through the CPMS platform and online sessions, and preparing e‐learning didactic material. A cornerstone of this networking is its facilitation of closer links between experts for the benefit of patients, as will be demonstrated in this session.
Genetic findings in paediatric patients with nystagmus
Authors: Arruti Natalia
Published: January 2025

Nystagmus, a condition characterized by involuntary eye movements, can be classified into two primary categories: infantile nystagmus (IN) and acquired nystagmus. IN typically manifests within the first 3‐6 months of life and can be idiopathic or associated with various ocular conditions, including inherited retinal dystrophies (IRD), albinism, or congenital cataracts. Acquired nystagmus appears later in life.

Diagnostic approaches for nystagmus involve comprehensive eye examinations, including optical coherence tomography (OCT), and electrophysiology testing to differentiate underlying ocular diseases. The advent of new medical devices allows for detailed recording of eye movements, capturing data on gaze positions, amplitude, frequency, intensity, phase speed, and other parameters, thereby enhancing diagnosis and management.

Recent advancements in genetics have significantly impacted the diagnostic process for nystagmus. Genetic testing is increasingly recognized as a crucial component, especially given the development of gene therapies for ocular conditions. We advocate for the routine use of genetic testing in paediatric patients with nystagmus to achieve definitive diagnoses and inform treatment strategies.

This study presents a retrospective review of paediatric nystagmus cases referred to our Genetics Department from January 1, 2020, to January 1, 2024. Our findings indicate a significant increase in molecular diagnostic rates following clinical phenotyping.

Genetic testing is instrumental in the diagnosis and management of paediatric nystagmus, particularly in the context of ongoing advancements in gene therapy for IRDs.
Development of resources for training machine learning systems for the eye
Authors: Lachke Salil A.
Published: January 2025

Regulation of distinct molecular pathways in coordinately developing tissues drives eye development. This process involves factors in signaling, transcription, translation and post‐transcriptional control that together determine the proteome of individual cells. Characterizing these regulatory events and their relationships with each other in distinct ocular tissues will lead to the derivation of gene regulatory networks (GRNs) for eye development, which in turn will allow building of the “developmental oculome” (Lachke, Maas (2010) Wiley Interdiscip Rev Syst Biol Med 2(3):305‐323 doi: 10.1002/wsbm.59). Toward this goal, we generated and analyzed various omics datasets on developing eye tissues, performed functional characterization of key molecules, and developed a web resource called iSyTE (Anand, Lachke (2017) Exp Eye Res 156:22‐33 PMC5026553; Kakrana et al (2018) Nucleic Acids Res 46(D1): D875‐D885 doi: 10.1093/nar/gkx837; Lachke (2022) Exp Eye Res 214:108889 PMC8792301). To extract further insights from these omics data, it is necessary to analyze them in the context of experimentally verified data on the eye. These data can be used for training machine learning systems to develop models for eye development. The data used for training represents a an important factor in machine learning systems, i.e. the quality of these data is a key contributor that determines the robustness of the resulting models. There is a wealth of molecular functional (i.e. experimental evidence‐based) data on the eye that has been generated by researchers worldwide over the past several decades. These individual regulatory data “nodes” (regulators and targets) – currently “static” in the literature with limited connectivity – hold rich potential to define detailed, and importantly, experimentally validated GRNs that can be used for training machine learning systems. As proof of principle, we have focused on ocular lens development and curated mechanistic data from individual gene perturbation evidences in the mouse from >100 original research articles. This has led to definition of thousands of experimentally validated relationships (edges) between key factors and their targets (nodes) in lens development. These resources serve as strong foundational data for training machine learning systems and represent the essential first step toward advancing our understanding of the natural computing governing eye development, and how its perturbation results in ocular developmental disorders.
Macular edema following ophthalmic surgery
Authors: Xirou Tina
Published: January 2025

Cystoid macular edema (CME) is a well known and common postoperative complication in cases undergoing ophthalmic surgeries. CME is the result of the disturbance of the blood‐aqueous barrier (BAB) and blood‐retinal barrier (BRB), leading to increased vascular permeability resulting in macular edema. Inflammation and vitreous traction on the macula may contribute to the development of macular edema. Fluid accumulation mainly in the outer plexiform layer is a significant cause of visual impairment. A higher incidence of CME observed in patients with pre‐existing vascular or inflammatory conditions and/or vitreous pathologies. The rationale for clinical or surgical treatment of macular edema is based on the understanding and the inhibition of these pathophysiological mechanisms. Advances in imaging technology such as optical coherence tomography (OCT) and OCT angiography (OCT‐A) are tremendously useful tools that provide important information regarding the anatomical integrity of the retina, its vascular damage, or the existence of epiretinal tissue that adds a tractional component. Pars plana vitrectomy (PPV) is a viable option in the management of CΜE, firstly helps to release the tractional component, sometimes underestimated, and secondly reduces the inflammatory components from the vitreous cavity. In our days vitrectomy has become a much safer surgical procedure, serious complications, such as retinal detachment are becoming less frequent and although the first line treatment for post‐surgical CME is medical, PPV should not be delayed in order to avoid the sequelae of longstanding macular edema.
Tear biomarkers for alzheimer's disease screening and diagnosis (the tearad study)
Authors: Gijs Marlies
Published: January 2025

The etiology of Alzheimer's disease (AD) can be determined with the use of biomarkers of amyloid‐beta (Aβ) deposition, neurofibrillary tangles and neurodegeneration. Cerebral spinal fluid (CSF) analysis or amyloid positron emission tomography (PET) imaging are currently used for biomarker determination. However, these tests are invasive, expensive and not widely available, thereby limiting their potential as a front‐line screener. Considering the expected increase of people affected by AD (152 million cases by 2050 worldwide), there will be a growing need for non‐invasive and cost‐effective tools allowing identification of patients in the earlier phases of the disease. Timely diagnosis is important to promote early and optimal management of the disease. Furthermore, this will be essential for future therapies as they may be more effective when started earlier in the disease process.

Tear fluid is an excellent source of neurological biomarkers. It can be obtained non‐invasively, making the process patient friendly and reducing the risk of complications. Additionally, tear fluid sampling is cost‐effective and requires minimal storage, making it accessible and practical for diagnostic purposes in the memory clinic and outpatient hospitals. For research purposes, tear fluid offers an attractive option for longitudinal studies and monitoring biomarker changes over time.

The main interest of the TearAD study is the use of tear biomarkers for AD. Tears covering the ocular surface are an important bio‐fluid containing thousands of molecules, including proteins, lipids, metabolites, nucleic acids, vitamins and electrolytes. We recently demonstrated that Aβ38, Aβ40 and Aβ42, total‐tau (t‐tau) and phosphorylated‐tau (p‐tau) are detectable in tear fluid. Tear t‐tau levels were significantly elevated in AD dementia patients compared to SCD patients, whereas tear p‐tau levels were only detectable in SCD, MCI and AD dementia patients, but not in cognitively healthy controls. Recently, Gharbiya and colleagues was able to reproduce the detection of p‐tau and Aβ42 in the tear fluid of MCI and AD dementia patients. In their study, levels of Aβ42 in tear fluid were significantly lower in MCI and AD dementia patients compared to cognitively healthy controls.

Our study is in line with others efforts that identified tear biomarkers for different neurological conditions, such as TNF‐alpha and oligomeric alpha‐synuclein for Parkinson's disease, alpha‐1 anti‐chymotrypsin for multiple sclerosis and mutant huntingtin for Huntington's disease. Together, these studies support the hypothesis that tear fluid may predispose to mirror pathophysiological changes in the central nervous system.
Results of implementation of new genomics in spanish national health system
Authors: Ayuso Carmen
Published: January 2025

In Spain, Inherited Retinal Dystrophies (IRD) gene diagnosis has been implemented from several decades ago (from 90's of last century), throughout the collaborative and multidisciplinary work of six teams located around the country (EsRetNet https://www.esretnet.org/, and others).

Along this time, we have developed guidelines to extend and improve gene testing for IRD in Spain (Ministry of Health, 2019 (https://portal.guiasalud.es/gpc/distrofias-hereditarias-retina/), and different molecular approaches have been implemented to increase the rate of molecular characterization of the patients, rising next generation sequencing (NGS) for routine, in 2013.

In January 2024, the pipeline for Gene testing in Spanish National Health System (NHS) was released, including ophthalmological genetic disorders (https://cgen.sanidad.gob.es/#/). This pipeline defines the conditions to be studied, using ICD 10 and ORPHA codification, the reasons to refer, and the molecular procedures to apply, among others.

Moreover, during the last 4 years the Spanish Program: Impact genomics has provided WGS for more than 2,000 Rare Diseases patients, including some with IRD, to explore the feasibility to implement WGS in NHS.

In the Department of Clinical Genetics of Fundacion Jimenez Diaz, Madrid, we have integrated in these national programs, as well as have introduced through research projects, the use of long reads WGS for IRD characterization.

As a result, we show the results of the cases studied in our centre. By March 2024, 6,025 unrelated affected IRD families had been recorded, 5,123 of them could be genetically studied, comprising around 8,000 cases. The families were distributed into 3 categories: Non syndromic Retinitis Pigmentosa (RP) (2,597 families; 60% characterized), Syndromic RP (651 families; 69% characterized), and NonRP (Macular Dystrophies, Cone Dystrophies, Cone Rod Dystrophies, etc) (1,875 families; 63% characterized)

In our cohort, the largest in the world from one single centre, 192 different genes were found as responsible for IRD, and about of 2,000 different causative variants were identified, half of them present in only one family. Despite this huge genetic heterogeneity, one fourth of the characterised families showed involvement of only seven genes (ABCA4, USH2A, RPGR, CRB1, RS1, PRPH2, and BEST1). RPE65 gene biallelic pathogenic variants were present in 30 families (around 50 affected cases).

This approach has allowed to implement not only the molecular characterization, but also to offer authorized treatment (Luxturna) for more than 30 Spanish cases in 6 centres and access to reproductive counselling and techniques, as PGT for severe IRD conditions.
Short and long‐read whole genome sequencing in inherited retinal diseases in finland
Authors: Turunen Joni
Published: January 2025

Genetic research can benefit from population isolates like Finland, as they tend to have a high concentration of deleterious alleles on a small number of low‐frequency variants. To investigate gene findings from the patients with inherited retinal disorders (IRD) in Finland, retrospectively collected data from the patients with IRDs treated between January 1st 2012, and December 31st 2020 at the Department of Ophthalmology, Helsinki University Hospital. Of the 638 patients who underwent genetic testing, 79% received a likely genetic diagnosis (504/638). The genetic findings corresponded to autosomal recessive (AR) inheritance in 242 patients, X‐linked (XL) in 158, autosomal dominant (AD) in 94, and mitochondrial inheritance in 22 patients. The most common genetic diagnosis was X‐linked retinoschisis as 17% (84/504) harbored pathogenic variants in RS1. The most common retinitis pigmentosa genes with causative variants were CERKL (8.5%, 43/504), RPGR (5.8%, 24/504), and EYS (5%, 25/504). CERKL variant c.375C>G, p.(Cys125Trp) and EYS c.1155T>A, p.(Cys385Ter) are frequent founder mutations. The Stargardt disease is less common than in other Western countries, the pathogenic variants in the ABCA4 gene were found in 24 patients. The genetic landscape of IRDs in Finland differs from other Western countries due to its specific isolated population history. The high yield of genetic findings is possibly explained by the enriched founder mutations in the population. One‐fifth of the patients lack genetic diagnosis, which might be due to shortages in the testing methods, i.e., non‐coding variants and complex structural genomic variants are missing. To address this problem, we have been utilizing the whole genome short‐ and long‐read sequencing methods to uncover new pathogenic variants. In the patients with presumable recessive inheritance and one pathogenic variant found, we have utilized short‐read genome sequencing to uncover regulatory regions and deep intronic variants. In two families with IRDs, we have found large structural variants in the RP1 and PRPH2 genes using Nanopore long‐read sequencing. In the future, we try to utilize the advantages of the population isolate to find unknown genes causing IRDs.
Advances in gene defect identification in France
Authors: Zeitz Christina
Published: January 2025

Inherited retinal diseases (IRDs) are a major cause of retinal degeneration leading to progressive blindness with limited therapeutic options. The last decades have seen promising therapeutic development urging for a better characterization and understanding of IRDs. The genetics of IRDs is heterogeneous but the advent of high throughput sequencing including whole genome sequencing have greatly accelerated our capacity to identify their genetic cause, which is a prerequisite for adequate genetic counseling and developing innovative treatments. The success rate in detecting the genetic cause is however far from being complete with about 30% of cases that remains unresolved. Since the establishment of our group in 2007, we are working on a large cohort of patients (more than 8000 cases) with annual growth of 800 cases clinically investigated at the rare disease center REFERET of the Quinze‐Vingts hospital, Paris, France. By analyzing >1000 cases with IRDs we delivered prevalence data and genotype‐phenotype correlations of known gene defects. Furthermore, our group was successful in identifying 8 novel gene defects and novel phenotype‐genotype associations in non‐syndromic and syndromic IRDs. Using Sanger sequencing, targeted next generation sequencing and whole exome sequencing we detect in ~70% of the cases with IRDs the underlying gene defect. Subsequently, the remaining cases are analyzed by whole genome sequencing (WGS) and either identify missed structural and deep intronic variants in known genes or novel candidate genes. One challenge with current genomic‐based technologies is the capacity to unravel numerous genetic variants that are difficult to interpret in the context of the disease. Therefore, there is a need to conduct systematic studies associated with relevant functional validation to better decipher underlying gene defects that will lead to an enhanced understanding of the disease and improve patients' care. To validate the pathogenic role of novel candidate genes and to further investigate the pathogenic mechanism, we developed a pipeline combining WGS, functional assays and disease modeling using induced pluripotent stem cells and more recently using zebrafish modelling. This revealed selected genetically unresolved families on which WGS analysis was performed and functional assays were initiated.
MR‐imaging biomarkers for eye tumors
Authors: Beenakker Jan‐Willem
Published: January 2025

In the clinical care for eye tumor patients, more and more applications of magnetic resonance imaging (MRI) have emerged in the last years. In retinoblastoma, for example, it is routinely used to screen for tumor invasion in the optic nerve. In uveal melanoma, the most frequently occurring primary intraocular malignancy in adults, MRI's three‐dimensional visualization of the tumor and surrounding structures give it an increasingly prominent place in radiotherapy planning. As a result of these clinical applications, functional MRI‐parameters, which are often obtained in the same scan session, gain in relevance. These functional sequences non‐invasively obtain tumor biomarkers that can be used for differential diagnosis, prognosis and response assessment. In this lecture we will cover the most important MR‐biomarkers, explain the underlying biology they probe, and highlight their clinical and scientific applications.

We will start with perfusion‐weighted MRI (PWI), a technique that obtains information on the tumor perfusion by administering an intravenous contrast agent while continuously imaging the eye. In addition to explaining the various pharmacokinetic models to quantitatively assess these data, we will show how, the clinically more feasible, semi‐quantitative assessment can already be used for differential diagnosis and early assessment of treatment response. Subsequently, we will discuss diffusion weighted imaging (DWI), a biomarker of the lesion's cellularity. Although it is a powerful biomarker to discriminate between benign and malignant lesions, its clinical value for prognosis and treatment response are still debated. We will end with a few clinical cases that demonstrate how these and other MR‐biomarkers complement the conventional ophthalmic imaging.
Vision research in community optical practices (e.g., product testing and development, including bsc and MSC theses; opportunities for big data studies)
Authors: Mihelčič Matjaž
Published: January 2025

In the optometrists’ offices, we usually do not expect to find research setups or laboratory instruments. There is however an increasing practice to host students who work on their Bachelor‐ and Master theses, gathering data for their studies. This combination is beneficial for the staff, as they refresh the knowledge in research; it is beneficial for patients, because many times, new / innovative equipment can be utilised during a standard exam. And it is beneficial for the students, since they have access to consenting patients, a non‐recruited group of subjects, which comprises a much more valid sample for observational studies then making recruitment at eye clinics or hospitals.

Ethical approval for the studies is usually obtained via university, but in some countries, it is possible to get it via practice, provided the supervisor fulfils the requirements.

In some instances, testing of new instruments can be done in optometric practices, providing the clinicians with insights of research and development, enabling them to give valuable input to industry.

Beside regular occupational vision tests, also assessment of visual function in special groups, like certain professions can be made (ex. Policemen, Firemen, Aircraft pilots, Astronauts). This way, the data about speciality needs can be collected and used for academic research.

Recent developments of AI‐assisted diagnostics and telemedicine have also addressed optometric practices – for example, the recently approved I‐screen programme, which is funded by European Commission via Horizon 22, employs pilot optometric practices throughout Europe as primary sites of patient acquisition. During regular eye‐exams, patients are screened with OCTs for early forms of dry age‐related macular degeneration. This group of retinal diseases is increasing in prevalence and treatment options are slowly becoming available. However, if patients with relevant clinical signs are not discovered timely, the outcome of the treatment is not as good, or treatment is not applicable at all. Again, an advantage of such studies is that they can provide information on the prevalences of ocular conditions in a community sample that better reflects the population than patients visiting clinics or hospitals.
Electronegative ergs and future directions
Authors: Mahroo Omar
Published: January 2025

The dark‐adapted electroretinogram (ERG) elicited by a strong flash delivered comprises a negative‐going a‐wave followed by a positive‐going b‐wave. The amplitude of the a‐wave is measured from the baseline to the a‐wave trough; the amplitude of the b‐wave is measured from the a‐wave trough to the b‐wave peak. In healthy individuals, the b‐wave amplitude exceeds that of the a‐wave. When the b‐wave is selectively reduced such that it is smaller than the a‐wave, this results in a “negative” waveform. This finding, in the context of a normal amplitude a‐wave, is termed an electronegative ERG and usually indicates impairment that is post‐phototransduction (for example impaired transmission at the photoreceptor to bipolar cell synapse or impairment in bipolar cell function). In the context of genetic retinal disease, this can considerably narrow the differential diagnosis in terms of likely associated genes. In the context of non‐genetic disease, this finding can point to specific pathologies, including in some cases paraneoplastic retinopathy. The physiological basis of electronegative ERGs will be discussed together with clinical strategies for arriving at the correct diagnosis. The second part of the talk will focus on future directions. Advances in ERG testing will be discussed, including novel devices, newer testing algorithms and refined methods of ERG analysis. Potential future applications of ERGs will be anticipated, both in the context of rare and common eye disease as well as in yielding insights into healthy retinal physiology.
Calculation of toric lenses and clinical aspects of toric lens implantation
Authors: Eppig Timo
Published: January 2025

Toric intraocular lenses (TIOL) are the method of choice to correct for corneal astigmatism in the course of cataract surgery. However, the use of TIOL requires special attention from patient consultation to preoperative examination, IOL calculation, preparation before surgery, surgery and the postoperative follow‐up. The surgeon must be aware that only the regular proportion of astigmatism can be corrected with TIOL. Therefore, the amount of regular astigmatism should be assessed prior to TIOL calculation. We give an insight into various calculation methods for TIOL and how to improve the surgical outcome. We discuss the pearls and pitfalls of TIOL in standard cataract surgery and for complicated cataract surgery e.g. after corneal transplantation.
Scanning laser ophthalmoscopy – basic optical principles
Authors: Irsch Kristina
Published: January 2025

Scanning Laser Ophthalmoscopy (SLO) produces an ocular fundus image by moving a focused laser beam via scanning mirrors over the retina in a grid pattern and registering the reflected light from each scanned point. In confocal SLO, a pinhole is placed in front of the detector to cut off scattered or defocused light coming from outside the point of interest, which otherwise can blur the image. This results in a focused, high‐contrast image of a single tissue layer located at the focal plane. Tomographic information can be extracted by moving the plane of the pinhole. The use of various wavelengths allows for different applications, such as fluorescein angiography, indocyanine green angiography, and autofluorescence imaging. This lecture will present the basic principles of SLO, as well as discuss notable applications and variants of the technology.
Adaptive optics – basic optical principles
Authors: Irsch Kristina
Published: January 2025

Adaptive Optics (AO) refers to a technique to compensate for distortions caused by optical aberrations in the media between the camera and the object being imaged. It was originally developed for use in astronomical telescopes to compensate for optical distortions induced by the inhomogeneous earth atmosphere. It has since evolved to become a powerful clinical tool in ophthalmology. In the eye, a “wavefront sensor” (aberrometer) measures the distortion of incoming light induced by inhomogeneities within the cornea and crystalline lens, which is then “undistorted” via reflection by a deformable mirror. AO thus enables imaging of the human retina with unprecedented resolution in vivo, such as revealing individual photoreceptors or the walls of blood vessels. One should note that AO by itself does not provide an image; rather an AO subsystem is incorporated into an existing imaging device. AO subsystems have thus far been successfully integrated into three ophthalmic imaging devices: fundus cameras, scanning laser ophthalmoscopes, and the OCT device. This lecture will introduce the basic principles of AO, illustrate its value with state‐of‐the‐art clinical examples, and discuss potential future applications in ophthalmology.
Panretinal photocoagulation of retina today
Authors: Schwartz Stephen G.
Published: January 2025

Panretinal photocoagulation (PRP) remains an important clinical tool in the care of many retinal vascular diseases, especially proliferative diabetic retinopathy (PDR) and neovascular glaucoma (NVG) due to ischemic central retinal vein occlusion (CRVO) and other causes.

As compared to anti‐vascular endothelial growth factor (anti‐VEGF) therapy, PRP offers the advantages of (1) much lower costs; (2) reduced or eliminated risks of endophthalmitis; and (3) greater duration of treatment effect, especially if the patient becomes lost to follow‐up. Also as compared with anti‐VEGF therapy, PRP offers the disadvantages of (1) greater risk of visual field loss; (2) possibly worse visual acuity (VA) outcomes; and (3) greater risk of diabetic macular edema (DME) in patients with PDR.

In the author's opinion, as anti‐VEGF utilization increases worldwide, PRP is probably underutilized today in the care of patients with PDR, CRVO, and NVG. There is a concern that anti‐VEGF masks signs of neovascularization. For example, patients with CME due to CRVO or DME associated with nonproliferative diabetic retinopathy (NPDR) are started on anti‐VEGF therapy. Over time, the CME/DME generally improves and the physician may then use a “treat and extend” protocol. At this stage of the treatment, there is a risk that, as the intervals extend beyond a certain timeframe, the patients become at risk for vitreous hemorrhage, NVG, and other vision‐threatening complications. In other words, the anti‐VEGF masks early signs of neovascularization of the disc (NVD), neovascularization elsewhere (NVE), and/or neovascularization of the iris (NVI).

The author recommends that patients with NPDR or nonischemic CRVO who are treated with long‐ term anti‐VEGF injections should be monitored for signs of progression to PDR or ischemic CRVO, respectively, especially when anti‐VEGF treatment intervals are extended beyond 2‐3 months. Certain patients may be considered for “prophylactic” treatment with PRP in this situation, especially those with sclerotic peripheral retinal vessels noted on ultra‐wide field fundus imaging.
Subthreshold micropulse laser (SML) treatment in retinal diseases
Authors: Gawęcki Maciej
Published: January 2025

Subthreshold micropulse laser became a popular treatment modality in different ocular diseases. If carefully performed, it is safe and often effective in management of entities, which involve retinal edema. Its role in management of degenerative diseases is still an open question for discussion, nevertheless it is used sometimes as an auxiliary option in inherited retinal disorders or dry form of macular degeneration. The course presents basics for SML action in retinal tissue in reference to classic laser photocoagulation. Results of SML application in different disorders are presented on the basis of published research. SML efficacy is also put in the context of other treatment modalities, such as anti‐VEGF injections or photodynamic therapy. Potential future perspective for its use is outlined and discussed.
Why and how does simulation‐based education work?
Authors: Filipe Helena Prior
Published: January 2025

Simulation‐Based Education (SBE) should be rooted in educational philosophies, and not simply defined by technology. SBE should underline ethical considerations like professionalism while mirroring and amplifying real‐world scenarios to optimize learning. Crafting vibrant SBE environments relies on mastering the nuances of how we learn best. Drawing from empirical evidence and learning theories is crucial in designing effective simulation‐based learning experiences.

We propose a journey illuminated by how SBE programs and their outcomes can be comprehensively enhanced, including patient safety and healthcare quality, through education science implementation. We will also delve into the rewards and hurdles of a comprehensive approach to SBE that weaves these educational experiences seamlessly into well‐structured SBE Centers.
Meta‐analysis of treatment outcomes for patients with m.117 | 8G>A MT‐ND4 leber hereditary optic neuropathy
Authors: Newman Nancy , Biousse Valérie , Yu‐Wai‐Man Patrick , Carelli Valerio , Vignal‐Clermont Catherine , Montestruc François , Taiel Magali , Sahel José‐Alain
Published: January 2025

Aims/Purpose: To assess the visual outcomes of patients with Leber hereditary optic neuropathy (LHON) harboring the m.11778G>A MT‐ND4 mutation treated with no treatment (natural history), idebenone or lenadogene nolparvovec gene therapy.

Methods: Efficacy outcomes were clinically relevant recovery (CRR) from nadir and final best‐corrected visual acuity (BCVA). For the natural history and idebenone groups, a systematic review of the literature and available clinical/regulatory reports was performed. A total of 5 and 13 natural history studies were selected for the meta‐analyses of CRR from nadir and final BCVA, while 7 and 3 idebenone studies were selected, respectively. For the lenadogene nolparvovec group, all phase 3 studies were included (RESCUE, REVERSE, RESTORE and REFLECT). The overall effect and its 95% confidence interval (CI) were estimated using a random effects model.

Results: For each meta‐analysis, patients had a mean age of approximately 30 years at the time of vision loss and were mostly (≥78%) men. The CRR from nadir [95% CI] at eye level was estimated at 17% [7%; 30%] (n = 316 eyes), 31% [24%; 40%] (n = 313) and 59% [54%; 64%] (n = 348) in untreated, idebenone‐treated and lenadogene nolparvovec‐treated eyes, respectively. This gradient of efficacy was also observed with CRR at the patient level and final BCVA.

Conclusions: There was a gradient of efficacy in all assessed visual outcomes, more marked for CRR than for final BCVA, with lenadogene nolparvovec gene therapy superior to idebenone treatment, and both superior to the natural history of the disease.
Changes in visual acuity categories in a historical population of patients with leber hereditary optic neuropathy from case record survey‐2 (CRS‐2)
Authors: Klopstock Thomas , Leroy Bart , Yu‐Wai‐Man Patrick , van Everdingen Judith , Krawczynski Maciej , Lamperti Costanza , Carelli Valerio , Llòria Xavier
Published: January 2025

Aims/Purpose: The Case Record Survey‐2 (CRS‐2; NCT02796274) aimed to establish the natural history of Leber hereditary optic neuropathy (LHON) in idebenone‐naïve patients. Here, we present change in visual acuity (VA) categories in subacute/dynamic eyes.

Methods: Retrospective clinical data were extracted from case records of LHON patients. Eligibility: aged ≥12 y, m.11778G>A, m.3460G>A, or m.14484T>C mitochondrial DNA mutation, symptom onset after 1999 and ≥2 VA assessments within 5 years of symptom onset. VA categories (logMAR): <1.00, 1.00–1.68, >1.68. Baseline was the first VA assessment after symptom onset; subacute/dynamic eyes were those with baseline ≤1 year after symptom onset.

Results: A total of 385 subacute/dynamic eyes had available data. Median (interquartile range; IQR) time from symptom onset to baseline was 1.3 (0.6–3.3) months; median (IQR) time from symptom onset to last visit was 8.8 (4.0–39.9) months. At baseline, 41% (157/385) of eyes were <1.00 logMAR. Of these, 30% (47/157) remained <1.00 logMAR at last visit; 41% (64/157) and 29% (46/157) worsened to 1.00–1.68 and >1.68 logMAR, respectively. At baseline, 36% (138/385) of eyes were 1.00–1.68 logMAR. Of these, 49% (67/138) remained 1.00–1.68 logMAR at last visit, 31% (43/138) worsened to >1.68 logMAR and 20% (28/138) improved to <1.00 logMAR. At baseline, 23% (90/385) of eyes were >1.68 logMAR. Of these, 68% (61/90) remained >1.68 logMAR at last visit; 27% (24/90) and 6% (5/90) improved to 1.00–1.68 and <1.00 logMAR, respectively.

Conclusions: The CRS‐2 study offers important insights into changes in VA category, based on baseline VA, in idebenone‐naïve eyes. However, given the variability in follow‐up time in retrospective natural history studies, caution must be taken in interpreting these results.
Systems pharmacology demonstrates broad‐spectrum efficacy in animal models of retinopathies
Authors: Leinonen Henri , Vainionpää Katri , Montaser Ahmed , Seemab Umair , Zhang Jianye , Occelli Laurence , Kolesnikov Alexander , Kefalov Vladimir , Kiser Philip , Tabaka Marcin , Petersen‐Jones Simon , Palczewski Krzysztof
Published: January 2025

Aims/Purpose: Excessive levels of the intracellular second messengers Ca2+ and cAMP have been linked with photoreceptor cell death during retinal degeneration (RD). We investigated if a combination (TMB) of common clinical drugs; tamsulosin and metoprolol (alpha‐ and beta‐adrenergic antagonists, Gq‐ and Gs‐coupled, respectively), and bromocriptine (a D2‐like dopamine‐receptor agonist, Gi‐coupled), that inhibit intracellular Ca2+ and cAMP signaling could be repurposed to mitigate RD.

Methods: Drug efficacy was tested in four distinct RD models: rd10, P23H, and Rpe65−/− mice; and PDE6A−/− dogs. The duration of the drug trials ranged from 1‐wk to 7‐months. Drug serum levels were measured by liquid chromatography‐mass spectrometry (LC‐MS). We used primarily photopic and scotopic electroretinography (ERG) and optical coherence tomography (OCT) to assess drug efficacy. Molecular biology methods such as immunohistochemistry, immunoblotting, and RNA‐sequencing (bulk and single cell) were used to document therapeutic mechanisms, as well as to confirm therapeutic effects.

Results: Dietary TMB improved cone function and slowed cone degeneration in P23H mice. In rd10 mice, both rod and cone function were significantly improved by TMB; and cone degeneration was significantly slowed. In dark‐reared rd10 mice, the drug efficacy was associated with decreased lipid peroxidation preceding the onset of cone degeneration. Dietary TMB improved retinal function and optomotor responses in Rpe65−/− mice but did not halt rod or cone degeneration. Seven‐month‐long subcutaneous sustained infusion of TMB into PDE6A−/− dogs led to higher cone counts at the end of the trial. TMB mitigated forskolin‐induced cAMP activity in an ex vivo retina preparation.

Conclusions: Our results suggest that simultaneous inhibition of Gs‐ and Gq‐coupled receptors and activation of Gi‐coupled receptors by a combination of existing drugs is a viable therapeutic strategy for RD.
Conditioned media from dental pulp stem cells to counteract the age‐related macular degeneration
Authors: Zerti Darin , Carozza Giulia , Pulcini Fanny , Lancia Loreto , Mattei Vincenzo , Monache Simona Delle , Maccarone Rita
Published: January 2025

Aims/Purpose: Age‐related macular degeneration (AMD) is the leading cause of blindness in the elderly. To date, there are no effective therapies to counteract the AMD towards the most severe stages characterized by a progressive loss of photoreceptors triggered by retinal pigmented epithelium dysfunction. Given their easily source and their high proliferative potential, Dental Pulp Stem Cells (DPSCs) showed promise for regenerative medicine. The main advantage of DPSCs is related to their immunosuppressive and immunoregulatory abilities, including the capability to promote regeneration of damaged tissues. It is well known the therapeutic potential of DPSCs secretome (conditioned media, CM), including trophic factors and cytokines, as a treatment of neurogenerative diseases. We evaluated the capability of DPSCs‐CM cultured in hypoxia and normoxic conditions to counteract retinal degeneration in an animal model of AMD.

Methods: DPSCs‐CM were intravitreally injected the day before the exposure of albino rats to high intensity light (LD). We evaluated the retinal function, and we performed morphological and molecular analysis a week after the LD, in accordance with the well‐established protocol of our light damage model.

Results: DPSCs‐CM obtained from hypoxia or normoxia, were able to preserve the retinal function, to reduce microglial activation and their migration toward outer nuclear layer (ONL). Furthermore, we demonstrated that the treatment with normoxic DPSCs‐CM limited the hot spot extension and preserved the ONL thickness better than the hypoxic DPSCs‐CM. The different concentrations of growth factors and cytokines detected in both CM played a key role in the understanding of the greatest protective effect of the normoxic‐CM compared to hypoxic‐CM.

Conclusions: Taken together, our study demonstrated that normoxic DPSCs‐CM represents an eligible candidate to counteract retinal degeneration and, therefore, a promising therapeutic agent for AMD.
Development of a bioreactor to examine the response of corneal cells to fluid shear stress
Authors: Bonizzi Matthia
Published: January 2025

Aims/Purpose: Mechanical stimulation plays an important role in regulating cell behavior. While several studies have examined how corneal epithelial cells respond to mechanical stimuli such as fluidic shear stress, little is known about how keratocytes respond. The purpose of this study was to design a bioreactor system to determine the effect of shear stress on the behavior of corneal epithelial cells and keratocytes in an in‐vitro 3D corneal hydrogel model.

Methods: A bioreactor chamber was made of PDMS containing 4 wells. 10 μl cell seeded hydrogels, consisting of 3.5 mg/ml collagen type I and 10 mM PEG (polyethylene‐glycol) containing 5 x 104 keratocytes, were added to each well to replicate the stroma. A 20 μm PCL (polycaprolactone) electrospun membrane was placed on top of each hydrogel and seeded with 1.6 x 103 corneal epithelial cells. The chamber was connected to a pump system to allow fluid to pass over the hydrogels at specified flow rates. Several tests were performed to validate the bioreactor and examine the cell response to fluid shear stress.

Results: The bioreactor was successfully tested for hydraulic sealing and sterility maintenance. The shear stress was calculated using a simple mechanical model and validated using computational fluid dynamics software. Preliminary studies using collagen hydrogels showed a high degree of contraction so PEG was introduced to the hydrogels to assist in stabilization. The response of corneal epithelial cells to different rates of shear stress was examined by analyzing the expression of YAP (Yes‐Associated‐Protein) and ZO‐1 (Zonula‐occludens‐1), both of which are known to be mechano‐sensitive.

Conclusions: The bioreactor has been developed and validated to apply shear stress to corneal hydrogel models. Further studies will further evaluate the response of epithelial cells and keratocytes to fluid flow at different shear rates.
Endothelial cell heterogeneity in arteriolar annuli: Implications in retinal blood flow regulation
Authors: González David Ramos , López‐Luppo Mariana , Jaramillo Patricia , Carretero Ana , Nacher Victor , Navarro Marc , Ruberte Jesús
Published: January 2025

Aims/Purpose: To investigate the endothelial cell heterogeneity in retinal arterioles with special focus in arteriolar annuli.

Methods: We compared structural and molecular characteristics between endothelial cells located in arteriolar annuli and endothelial cells located in other regions of retinal arterioles. Immunohistochemical, histochemical, and electron transmission microscopy assays were performed.

Results: Molecular analysis showed that arteriolar annuli endothelial cells showed a decreased expression of PECAM‐1 together with an increased expression of NADPH‐diaphorase in comparison with other regions of retinal arterioles. PECAM‐1 is involved cell‐cell adhesion. Therefore, this result suggests a decrease in cellular adhesion at the arteriolar annuli. NADPH diaphorase reflects nitric oxide synthase activity. Thus, its increase indicates NO synthesis suggesting localized vasodilation and decrease of platelet aggregation at arteriolar annuli. An increased expression of von Willebrand factor in concomitance with a higher presence of Weibel‐Palade bodies was also observed in endothelial cells at the arteriolar annuli, suggesting that von Willebrand factor is stored and released in a regulated manner. Furthermore, transmission electron microscopy showed the presence of two endothelial cell subtypes in arteriolar annuli: activated endothelial cells, and shear stress‐adapted endothelial cells. Activated endothelial cells exhibited enlarged nuclei with chromatin condensed in the periphery, swollen perinuclear space, and an increased number of vesicles and caveolae. By contrast, shear stress‐adapted endothelial cells were thicker than the rest of endothelial cells and showed bilobulated nuclei, a well‐developed endoplasmic reticulum, as well as large increase in the number of mitochondria.

Conclusions: All our results suggest that endothelium at arteriolar annuli, a structure suggested to regulate retinal blood flow by exerting a sphincter‐like activity, is formed by a subset of endothelial cells endowed with distinctive structural and molecular features which allow them to play a key role in the maintenance of blood flow through two mechanisms: the establishment of an antithrombotic milieu, and the vasodilation of arteriolar annuli.
Cryopreservation of corneal endothelial cells in vitro, ex vivo, and on a tissue engineered endothelial graft
Authors: Sagnial Tomy , Coban Melis , Aouimeur Inès , Coulomb Louise , Philippe Gain , He Zhiguo
Published: January 2025

Aims/Purpose: In response to the global shortage of corneas, alternatives such as cell injection therapy and tissue‐engineered endothelial keratoplasty (TEEK) have emerged, both relying on the mass production of primary cultured corneal endothelial cells (CECs). Cryopreservation of corneas (the primary cell culture source), cultured CECs (in vitro), and TEEK grafts (final products) is crucial to facilitate their industrialization and clinical application. While corneal cryopreservation has long been a challenge, advancements in cryoprotectants warrant a renewed investigation. This study aims to assess various cryopreservation methods for CECs n the three different states.

Methods: Ten cryopreservation media and varying cooling rates (‐2°C/min, ‐1°C/min, or ‐0.5°C/min) were first tested on cultured CECs. After thawing, cell survival rates were assessed using Trypan blue staining and an automated cell counter. Subsequently, the best conditions identified for cultured CECs were applied to native CECs adhered to their Descemet's membrane and CECs on TEEKs. Post‐thawing viability was assessed using triple labeling with Hoechst, Ethidium, and Calcein‐AM (Pipparelli et al. IOVS 2011).

Results: A gradual cooling rate of ‐1°C per minute and the cryopreservation medium CryoStor CS10 provided the best conditions for in vitro CECs, ensuring an average viability of 91 ± 1% post‐cryopreservation. However, applying the same conditions to native CECs on corneas or CECs on TEEK grafts resulted in a viability of less than 80%. Upon thawing, CECs tended to detach easily from the DM or bio‐engineered grafts, leading to significant areas without cells.

Conclusions: Cryopreservation is effective for in vitro cultured CECs but remains very challenging for CECs attached to the DM or TEEKs. The next step will be to address cell attachment issues during cryopreservation.

References

Aurélien Pipparelli, Gilles Thuret, David Toubeau, Zhiguo He, Simone Piselli, Sabine Lefèvre, Philippe Gain, Marc Muraine; Pan‐Corneal Endothelial Viability Assessment: Application to Endothelial Grafts Predissected by Eye Banks. Invest. Ophthalmol. Vis. Sci. 2011;52(8):6018‐6025. https://doi.org/10.1167/iovs.10-6641.
Adipose‐derived mesenchymal stem cells (admscs) and retinal pigment epithelial cells (RPE‐1) interactions in stress environments via tunneling nanotubes
Authors: Gozel Merve , Senkoylu Karya , Kesim Cem , Hasanreisoğlu Murat
Published: January 2025

Aims/Purpose: The study aims to elucidate the potential role of TNT‐mediated intercellular communication between the AdMSCs and RPE‐1 cells in reducing stress‐induced damage.

Methods: Oxidative stress and serum starvation were used as stress to create TNTs between the AdMSC and RPE‐1 cells. Immunofluorescence and scanning electron microscopy were used to show that TNT formation. Following stress conditions, the cells' viability was examined by CTG assay, and the levels of reactive oxygen species (ROS) were measured by H2DCFH‐DA probes. Microscopy showed that JC‐1 labelled mitochondrial exchange occurs between cells via TNTs. To prevent TNTs, a transmembrane culture system was used and evaluated how to effect on cell viability and changes of ROS levels.

Results: We examined how TNTs support mitochondrial transport and intercellular communication between AdMSCs and RPE‐1 during stress. We discovered that TNT‐mediated mitochondrial translocation from AdMSCs to RPE‐1 contributes to both increased cell survival and a decrease in ROS levels. We showed that AdMSCs and RPE‐1 had a direct connection that was essential for stress recovery. After stress‐induced damage, co‐culture improved vitality and maintained retinal function. Because mechanical restriction of TNT synthesis reduced cell viability and raised ROS levels, it is clear that TNTs are essential for cellular defence.

Conclusions: Overall, our study provides valuable insights into the cellular mechanisms underlying stress response and underscores the therapeutic promise of AdMSC derived TNTs in preserving retinal health.