Brolucizumab in recalcitrant neovascular age-related macular degeneration-real-world data in Chinese population

This retrospective study aimed to determine the short-term efficacy and safety of brolucizumab treatment for recalcitrant neovascular age-related macular degeneration (nAMD) in a real-world setting in Taiwan. Recalcitrant nAMD patients who were treated with brolucizumab from November 2021 to August 2022 at Taipei Veterans General Hospital were included. Patients were followed for 3 months after switching to brolucizumab. The primary outcomes were changes in mean best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to the third month. The secondary outcomes included the incidence of intraocular inflammation (IOI), proportion of patients with subretinal and intraretinal fluid (SRF and IRF), and change in pigment epithelial detachment (PED) height from baseline to the third month. The significance level was considered as p < .05 in all tests. A total of 38 patients (40 eyes) with a mean (±SD) age of 76.3 (±10.84) years were included. The baseline BCVA was 0.92±0.64 logMAR, and the CRT and PED height were 329.0±171.18 and 189.8±114.94 um, respectively. The patients had a significant reduction in CRT and resolution of IRF and SRF from baseline to the third month. There were numerical improvements in mean BCVA and PED height, but they were not significant. The percentages of achieving at least 0.1, 0.2, and 0.3 logMAR (equivalent to 5, 10, 15 ETDRS letters) visual gain were 50%, 37.5%, and 30%, respectively, during the first 3 months of follow-up. No IOI occurred in these patients. This study demonstrated that brolucizumab had good short-term structural and functional efficacy in recalcitrant nAMD patients.

HLA-Homozygous iPSC-Derived Mesenchymal Stem Cells Rescue Rotenone-Induced Experimental Leber's Hereditary Optic Neuropathy-like Models In Vitro and In Vivo

BACKGROUND

Mesenchymal stem cells (MSCs) hold promise for cell-based therapy, yet the sourcing, quality, and invasive methods of MSCs impede their mass production and quality control. Induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) can be infinitely expanded, providing advantages over conventional MSCs in terms of meeting unmet clinical demands.

METHODS

The potential of MSC therapy for Leber's hereditary optic neuropathy (LHON) remains uncertain. In this study, we used HLA-homozygous induced pluripotent stem cells to generate iMSCs using a defined protocol, and we examined their therapeutic potential in rotenone-induced LHON-like models in vitro and in vivo.

RESULTS

The iMSCs did not cause any tumorigenic incidence or inflammation-related lesions after intravitreal transplantation, and they remained viable for at least nine days in the mouse recipient's eyes. In addition, iMSCs exhibited significant efficacy in safeguarding retinal ganglion cells (RGCs) from rotenone-induced cytotoxicity in vitro, and they ameliorated CGL+IPL layer thinning and RGC loss in vivo. Optical coherence tomography (OCT) and an electroretinogram demonstrated that iMSCs not only prevented RGC loss and impairments to the retinal architecture, but they also improved retinal electrophysiology performance.

CONCLUSION

The generation of iMSCs via the HLA homozygosity of iPSCs offers a compelling avenue for overcoming the current limitations of MSC-based therapies. The results underscore the potential of iMSCs when addressing retinal disorders, and they highlight their clinical significance, offering renewed hope for individuals affected by LHON and other inherited retinal conditions.

Designing Patient-Centered Health Education Materials for Radiation Dermatitis in Breast Cancer Patients: A Pilot Study and Single-Center Clinical Trial

PURPOSE/OBJECTIVE(S)

For breast cancer patients receiving radiotherapy (RT), radiation dermatitis is the most commonly experienced discomfort. However, patients usually do not participate in the design of health education materials regarding radiation dermatitis. We designed a pilot study to investigate the unmet need of breast cancer patients who would be receiving RT at our department and created a patient-centered educational video. We initiated a single-arm clinical trial to evaluate the effectiveness of the video in improving patient and their family's knowledge of radiation dermatitis, alleviating their anxiety, and helping patients improve self-care skills during RT course.

MATERIALS/METHODS

The pilot study was executed in a radiation oncology department of a tertiary medical center in Taiwan. We designed a questionnaire to explore new breast cancer patients' idea of a comprehensive pre-RT health education. Enrolled patients would fill out an electronic questionnaire during their first visit at our outpatient clinic. They were asked to select at most two of the following items they considered most important for pre-RT health education: (1) The mechanism behind RT; (2) Self-care skills for irradiated skin; (3) Activities to be avoided during RT course; (4) The toxicity grading of radiation dermatitis. Given the above information, we created a 4-minute video set in a clinical scenario of a patient receiving pre-RT health education from a nurse. A single-arm clinical trial (IRB approval number: CMUH111-REC2-121) is currently recruiting. The video was launched on YouTube (Link: https://youtu.be/O1uTXpS_ed0) to give patients easy access to the video. Enrolled patients would complete Skindex-16 survey (translated into Chinese) at 3 timepoints: during their first visit at our clinic, in the middle of RT course, and at the first post-RT follow-up visit. Cronbach's alpha test was applied to determine the internal consistency of the questionnaires.

RESULTS

The pilot study included 19 patients with an average age of 46.6 (range: 34 to 69) years old. All patients' primary language was Chinese Mandarin. Most patients (84%) received at least secondary education. We found by surprise that RTOG skin toxicity grading was considered very important for most patients (79%), while less than half (42%) found the mechanism behind RT important. The internal validity of the Chinese version of Skindex-16 was good (Cronbach's alpha score = 0.87). For the recruiting trial, we have enrolled 10 patients and planned to close the trial upon enrolling 50 participants. The study result should be available before August 2023.

CONCLUSION

We suggest to actively involve patients in designing health education materials for patient-centered care. Toxicity grading of radiation dermatitis should be included in pre-RT health education for breast cancer patients. Whether the educational video helps reduce patients' anxiety and the incidence of severe radiation dermatitis will soon be answered by our ongoing clinical trial.

TMEM132D and VIPR2 Polymorphisms as Genetic Risk Loci for Retinal Detachment: A Genome-Wide Association Study and Polygenic Risk Score Analysis

Purpose

Retinal detachment (RD) is a sight-threatening ocular disease caused by separation of the neurosensory retina from the underlying retinal pigment epithelium layer. Its genetic basis is unclear because of a limited amount of data. In this study, we aimed to identify genetic risk loci associated with RD in participants without diabetes mellitus and to construct a polygenic risk score (PRS) to predict the risk of RD.

Methods

A genome-wide association study was conducted using data from the Taiwan Biobank to identify RD risk loci. A total of 1533 RD cases and 106,270 controls were recruited, all of whom were Han Chinese. Replication studies were performed using data from the UK Biobank and Biobank Japan. To construct the PRS, a traditional clumping and thresholding method was performed and validated by fivefold cross-validation.

Results

Two novel loci with significant associations were identified. These two genes were TMEM132D (lead single nucleotide polymorphism [SNP]: rs264498, adjusted-P = 7.18 × 10-9) and VIPR2 (lead SNP: rs3812305, adjusted-P = 8.38 × 10-9). The developed PRS was effective in discriminating individuals at high risk of RD with a dose-response relationship. The quartile with the highest risk had an odds ratio of 1244.748 compared to the lowest risk group (95% confidence interval, 175.174-8844.892).

Conclusions

TMEM132D and VIPR2 polymorphisms are genetic candidates linked to RD in Han Chinese populations. Our proposed PRS was effective at discriminating high-risk from low-risk individuals.

Same-Day Bilateral Intravitreal Dexamethasone Implants for the Treatment of Diabetic Macular Edema

INTRODUCTION

The aim of this study was to evaluate the outcomes and complications associated with the use of same-day bilateral intravitreal dexamethasone (DEX) implants for the treatment of diabetic macular edema (DME).

METHODS

This retrospective analysis of an open-label, multicenter, consecutive case series included 130 eyes of 65 patients with bilateral DME who were treated with intravitreal DEX implants. The patients were divided into two groups: a control group (comprising 40 eyes treated with an alternating unilateral regimen) and a study group (comprising 90 eyes treated with concomitant bilateral DEX implants). All patients were followed up monthly after implantation. The changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to sixth month after implantation, and ocular adverse effects such as intraocular pressure, cataract, and tolerability of bilateral implantation were reviewed. The primary endpoint was to assess the safety of the same-day bilateral treatment protocol. The secondary endpoints focused on evaluating the functional and anatomical changes associated with bilateral simultaneous or alternating implantations.

RESULTS

At 6 months after implantation, mean BCVA increased and CRT decreased in both groups. Moreover, no serious ocular adverse effects were observed. In addition, no differences were observed between the two groups in the number of patients who required extra follow-up visits or the number of extra visits made in addition to the treatment schedule.

CONCLUSIONS

Same-day bilateral intravitreal DEX implants are associated with a low complication rate and are well tolerated by patients. This safe practice may optimize efficiency and reduce the burden on both the health-care system and patients, when used to treat bilateral DME.

Assessment of histological and immunohistochemical features of retinal tissues using a novel tissue submission procedure

We introduce a novel tissue submission procedure without additional equipment or storage facilities for assessing the histological and immunohistochemical features of retinal tissues. In total, 150 specimens were collected from patients who underwent vitrectomy or macular surgery from January to December 2020. Ninety-eight specimens were submitted using the new procedure, and 58 specimens were submitted as flat-mount slides to compare specimen adequacy. The tissues submitted using the new procedure were subjected to paraffin-embedding and sectioning for hematoxylin & eosin staining. Additional immunohistochemical analysis was performed to assess the cellular composition in retinal tissues with diverse etiologies. The new submission procedure had an adequacy ratio of 75.51%, which was comparable to that of the flat-mount method (p = 0.1397). The new method could produce high-quality images of histological features of tissues and facilitated immunohistochemical analysis to demonstrate cell origins. More glial cells (p = 0.000) and myofibroblasts (p = 0.012) were detected in the epiretinal membranes (ERMs) than in the internal limiting membranes (ILMs). Subgroup analysis revealed that secondary ERMs contained more macrophage-like cells (p = 0.001) and retinal pigment epithelial cells (p = 0.000) than did idiopathic ERMs. Our novel tissue submission procedure can be applied to routine clinical practice. Our study provides additional histological and immunohistochemical evidence of cellular components in retinal tissues based on a large number of human tissue samples. Moreover, tissues submitted using the new method can be permanently preserved, enabling future investigation for potential prognostic or therapeutic targets.

Nanoparticles-mediated CRISPR-Cas9 gene therapy in inherited retinal diseases: applications, challenges, and emerging opportunities

Inherited Retinal Diseases (IRDs) are considered one of the leading causes of blindness worldwide. However, the majority of them still lack a safe and effective treatment due to their complexity and genetic heterogeneity. Recently, gene therapy is gaining importance as an efficient strategy to address IRDs which were previously considered incurable. The development of the clustered regularly-interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system has strongly empowered the field of gene therapy. However, successful gene modifications rely on the efficient delivery of CRISPR-Cas9 components into the complex three-dimensional (3D) architecture of the human retinal tissue. Intriguing findings in the field of nanoparticles (NPs) meet all the criteria required for CRISPR-Cas9 delivery and have made a great contribution toward its therapeutic applications. In addition, exploiting induced pluripotent stem cell (iPSC) technology and in vitro 3D retinal organoids paved the way for prospective clinical trials of the CRISPR-Cas9 system in treating IRDs. This review highlights important advances in NP-based gene therapy, the CRISPR-Cas9 system, and iPSC-derived retinal organoids with a focus on IRDs. Collectively, these studies establish a multidisciplinary approach by integrating nanomedicine and stem cell technologies and demonstrate the utility of retina organoids in developing effective therapies for IRDs.

Pseudophakic pupillary block after phacoemulsification and posterior chamber intraocular lens implantation: Cause identification and treatment refinement

BACKGROUND

Pseudophakic pupillary block (PPB) was rare in patients who undergo phacoemulsification and posterior chamber intraocular lens (PCIOL) implantation. Laser peripheral iridotomy was the most reported but ineffective treatment in the literature.

METHODS

Retrospective, interventional case series of patients who developed PPB in Taipei Veterans General Hospital from 2017 to 2021. Clinical course, diagnostic methods, treatment and outcomes were recorded and discussed.

RESULTS

Four eyes of three patients were documented. All of them had diabetes and diabetic retinopathy. Anterior segment Optical coherence tomography (OCT) of these patients showed an exudative membrane at the peripapillary area while slit lamp image could not provide a clear view due to the severely edematous corneal condition. Laser peripheral iridotomy and yttrium aluminum garnet (YAG) laser aiming to the peripapillary exudation were applied to break the PPB successfully.

CONCLUSION

Diabetes mellitus, intravitreal injection and inflammation are crucial risk factors for PPB. Anterior segment OCT can be a useful diagnostic tool for the detection of the peripapillary exudative membrane while corneal clarity is compromised due to high intraocular pressure. In addition to peripheral laser iridotomy, an effective approach to resolve PPB may be the use of the YAG laser to break the exudative membrane.

Correlations between Clinical and Histopathologic Characteristics in Idiopathic Epiretinal Membrane

PURPOSE

To investigate correlations between clinical and histopathologic characteristics of idiopathic epiretinal membrane (ERM).

DESIGN

Retrospective interventional case series.

PARTICIPANTS

In total, 87 eyes from 87 patients with idiopathic ERM who underwent pars plana vitrectomy with peeling of the ERM from 2019 to 2020 were included.

METHODS

The outcomes of clinical ophthalmic examination, including measurement of best-corrected visual acuity (BCVA) and spectral-domain OCT (SD-OCT), before and after surgery were reviewed. Surgical specimens were fixed in formalin and embedded in paraffin for histologic and immunohistochemical analysis.

MAIN OUTCOMES MEASURES

The association between morphological characteristics revealed on SD-OCT images and the cellular composition of the surgically excised ERM demonstrated with immunohistochemical staining were the main outcome measures. Changes in the BCVA and central macular thickness (CMT) were assessed through a comparison of preoperative and postoperative measurements.

RESULTS

Based on SD-OCT morphological characteristics in the foveal area, 15 cases were classified into group 1A (mainly outer retinal thickening), 39 into group 1B (more tenting of the outer retina and distorted inner retina), and 33 into group 1C (prominent inner retina thickening). Overall, postoperative final BCVA and CMT at 1 year improved in all groups. Patients who presented with a better initial BCVA exhibited a more favorable final BCVA. Epiretinal membranes in group 1C demonstrated the greatest decrease in CMT compared with those in groups 1B and 1A, but the final CMT did not differ among the groups. A negative correlation between the density of hyalocytes (P = 0.003) and myofibroblasts (P = 0.047) was noted between the 3 groups. Total cell density and glial cell density of the ERMs were strongly associated with poor final BCVA and BCVA improvement.

CONCLUSIONS

The present study provides new histopathologic information regarding the formation and progression of idiopathic ERM. Glial cell proliferation plays a predominant role in these processes. Epiretinal membranes with high cellularity and glial cell density may cause damage to the retina structure, resulting in poor postoperative visual outcomes. These findings provide additional evidence supporting early surgical intervention in patients with idiopathic ERM reported with visual disturbance.

Pluripotent Stem Cells in Clinical Cell Transplantation: Focusing on Induced Pluripotent Stem Cell-Derived RPE Cell Therapy in Age-Related Macular Degeneration

Human pluripotent stem cells (PSCs), including both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), represent valuable cell sources to replace diseased or injured tissues in regenerative medicine. iPSCs exhibit the potential for indefinite self-renewal and differentiation into various cell types and can be reprogrammed from somatic tissue that can be easily obtained, paving the way for cell therapy, regenerative medicine, and personalized medicine. Cell therapies using various iPSC-derived cell types are now evolving rapidly for the treatment of clinical diseases, including Parkinson's disease, hematological diseases, cardiomyopathy, osteoarthritis, and retinal diseases. Since the first interventional clinical trial with autologous iPSC-derived retinal pigment epithelial cells (RPEs) for the treatment of age-related macular degeneration (AMD) was accomplished in Japan, several preclinical trials using iPSC suspensions or monolayers have been launched, or are ongoing or completed. The evolution and generation of human leukocyte antigen (HLA)-universal iPSCs may facilitate the clinical application of iPSC-based therapies. Thus, iPSCs hold great promise in the treatment of multiple retinal diseases. The efficacy and adverse effects of iPSC-based retinal therapies should be carefully assessed in ongoing and further clinical trials.

Temporal fluctuations of cardiovascular parameters after intravitreal injections

BACKGROUND

Despite the effectiveness of intravitreal injection (IVI) of anti-vascular endothelial growth factor in treating retinal diseases, there remains a paucity of evidence on potential systemic risks associated with this procedure. This study aims to investigate cardiovascular parameters and the risk of hypertensive urgency after IVIs.

METHODS

Patients who received IVIs for retinal/macular diseases were enrolled retrospectively. Patients who received cataract surgeries were enrolled as controls. Systolic and diastolic blood pressure (BP) and heart rate were measured 10 minutes before, immediately after, and more than 30 minutes after IVIs and cataract surgery. Multivariate analysis was performed to evaluate risk factors for hypertensive urgency.

RESULTS

Seventy patients who received IVIs and 95 patients who received cataract surgeries were enrolled. A higher preoperative systolic BP was found in the IVI groups than in the control group (147.0 ± 22.9 vs 136.3 ± 21.8 mmHg, respectively). The patients who received IVIs had a higher increase in perioperative systolic BP immediately after the procedure than the controls (17.43 ± 20.53 mmHg vs 9.11 ± 18.92 mmHg, p = 0.009). The IVI procedure (odds ratio [OR] 4.84, p = 0.008), preoperative systolic BP ≥160 mmHg (OR 17.891, p = 0.001, compared to preoperative systolic BP <140 mmHg), and underlying hypertension (OR 3.305, p = 0.041) were risk factors for hypertensive urgency immediately after the IVIs.

CONCLUSION

We found a transient increase in BP after IVIs, which may have been associated with hypertensive urgency and related cardiovascular disorders in older patients and in those with relevant comorbidities. Clinicians should pay more attention to these patients before performing IVIs.

Deep learning to infer visual acuity from optical coherence tomography in diabetic macular edema

Purpose

Diabetic macular edema (DME) is one of the leading causes of visual impairment in diabetic retinopathy (DR). Physicians rely on optical coherence tomography (OCT) and baseline visual acuity (VA) to tailor therapeutic regimen. However, best-corrected visual acuity (BCVA) from chart-based examinations may not wholly reflect DME status. Chart-based examinations are subjected findings dependent on the patient’s recognition functions and are often confounded by concurrent corneal, lens, retinal, optic nerve, or extraocular disorders. The ability to infer VA from objective optical coherence tomography (OCT) images provides the predicted VA from objective macular structures directly and a better understanding of diabetic macular health. Deviations from chart-based and artificial intelligence (AI) image-based VA will prompt physicians to assess other ocular abnormalities affecting the patients VA and whether pursuing anti-VEGF treatment will likely yield increment in VA.

Materials and methods

We enrolled a retrospective cohort of 251 DME patients from Big Data Center (BDC) of Taipei Veteran General Hospital (TVGH) from February 2011 and August 2019. A total of 3,920 OCT images, labeled as “visually impaired” or “adequate” according to baseline VA, were grouped into training (2,826), validation (779), and testing cohort (315). We applied confusion matrix and receiver operating characteristic (ROC) curve to evaluate the performance.

Results

We developed an OCT-based convolutional neuronal network (CNN) model that could classify two VA classes by the threshold of 0.50 (decimal notation) with an accuracy of 75.9%, a sensitivity of 78.9%, and an area under the ROC curve of 80.1% on the testing cohort.

Conclusion

This study demonstrated the feasibility of inferring VA from routine objective retinal images.

Translational relevance

Serves as a pilot study to encourage further use of deep learning in deriving functional outcomes and secondary surrogate endpoints for retinal diseases.

Polygenic Risk Score Improves Cataract Prediction in East Asian Population

Cataracts, characterized by crystalline lens opacities in human eyes, is the leading cause of blindness globally. Due to its multifactorial complexity, the molecular mechanisms remain poorly understood. Larger cohorts of genome-wide association studies (GWAS) are needed to investigate cataracts’ genetic basis. In this study, a GWAS was performed on the largest Han population to date, analyzing a total of 7079 patients and 13,256 controls from the Taiwan Biobank (TWB) 2.0 cohort. Two cataract-associated SNPs with an adjustment of p < 1 × 10−7 in the older groups and nine SNPs with an adjustment of p < 1 × 10−6 in the younger group were identified. Except for the reported AGMO in animal models, most variations, including rs74774546 in GJA1 and rs237885 in OXTR, were not identified before this study. Furthermore, a polygenic risk score (PRS) was created for the young and old populations to identify high-risk cataract individuals, with areas under the receiver operating curve (AUROCs) of 0.829 and 0.785, respectively, after covariate adjustments. Younger individuals had 17.45 times the risk while older people had 10.97 times the risk when comparing individuals in the highest and lowest PRS quantiles. Validation analysis on an independent TWB1.0 cohort revealed AUROCs of 0.744 and 0.659.

Evaluation of a remote telemedicine platform using a novel handheld fundus camera: Physician and patient perceptions from real-world experience

BACKGROUND

Although teleophthalmology has gained traction in recent years, it is at the center of the coronavirus disease pandemic. However, most hospitals are not ready owing to a severe lack of real-world experience. Furthermore, a limited number of studies have evaluated telemedicine applications on remote islands. This study aimed to evaluate real-world clinical and referral accuracy, image quality, physician-perceived diagnostic certainty, and patient satisfaction with telemedicine eye screening using a novel handheld fundus camera in a rural and medically underserved population.

METHODS

This prospective study included 176 eyes from a remote island. All participants underwent a comprehensive ophthalmic examination. Nonmydriatic retinal images obtained using a handheld fundus camera were reviewed by two retinal specialists to determine image quality, diagnosis, and need for referrals. The agreement of diagnosis between image-based assessments was compared with that of binocular indirect ophthalmoscopic assessments.

RESULTS

Image quality of fundus photographs was considered acceptable or ideal in 97.7% and 95.5% of eyes assessed by two reviewers, respectively. There was considerable agreement in diagnosis between the indirect ophthalmoscopic assessment and image-based assessment by two reviewers (Cohen's kappa = 0.80 and 0.78, respectively). Likewise, substantial agreement was achieved in the referrals. The sensitivity for referable retinopathy from the two reviewers was 78% (95% confidence interval [CI], 57%-91%) and 78% (95% CI, 57%-91%), whereas specificity was 99% (95% CI, 95%-99%] and 98% (95% CI, 93%-99%), respectively. For physicians' perceived certainty of diagnosis, 93.8% and 90.3% were considered either certain or reliable. Overall, 97.4% of participants were satisfied with their experiences and greatly valued the telemedicine services.

CONCLUSION

Novel fundus camera-based telemedicine screening demonstrated high accuracy in detecting clinically significant retinopathy in real-world settings. It achieved high patient satisfaction and physician-perceived certainty in diagnosis with reliable image quality, which may be scaled internationally to overcome geographical barriers under the global pandemic.

Three-Year Outcomes of Intravitreal Aflibercept Injections for Retinal Angiomatous Proliferation According to Disease Stage

INTRODUCTION

To evaluate the outcomes of intravitreal aflibercept injections for retinal angiomatous proliferation (RAP) according to disease stage.

METHODS

This retrospective chart review included 68 eyes of 53 individuals diagnosed as having RAP and 109 neovascular age-related macular degeneration (nAMD) eyes of 109 patients as controls. All patients received intravitreal injections of aflibercept in a real-world setting. The main outcome measures were the changes in the mean of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) as well as the total number of injections received during the 3-year follow-up period.

RESULTS

The average BCVA and CRT changes in eyes affected by RAP and the controls at 3 years were non-significant. Both populations received a similar number of injections. After 3 years of treatment, patients with RAP had visual decline despite stable anatomical outcomes. Approximately 50% of the eyes with stage II RAP exhibited significant BCVA decline at the end of the third year. Among those eyes that had deteriorated BCVA, persistently worsening BCVA and thinning CRT were observed from year 2 to year 3.

CONCLUSION

Similar to treating nAMD, intensive injections or aggressive treatment strategies are required to treat RAP to achieve optimal visual outcomes in a real-world setting. The response to aflibercept treatment at the second year is associated with the final visual outcome of eyes with stage II RAP lesions.

Therapeutic effect of simultaneous intravitreal dexamethasone and aflibercept on diabetic macular edema

AIMS

To report the effect of simultaneous intravitreal dexamethasone (DEX) and aflibercept for the treatment of diabetic macular edema (DME).

METHODS

This retrospective analysis of an open-label, multicenter, consecutive case series included 102 eyes of 81 patients with DME. Patients were selected into two groups. The control group consisted of 50 eyes treated with aflibercept alone, and the combination group consisted of 52 eyes treated with simultaneous DEX implant and aflibercept injection. The primary endpoints were changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 6. The secondary endpoint was the interval of retreatment.

RESULTS

Baseline BCVA increased and CRT decreased at 6 months in both groups. Pseudophakic eyes in the combination group exhibited significantly greater BCVA improvement compared with phakic eyes (p = 0.031). Fewer intravitreal treatments were required for eyes treated with combination therapy than for those treated with aflibercept alone (1.56 ± 0.54 vs. 4.04 ± 1.26, p < .0001), with a mean retreatment interval of 3.66 ± 0.69 months.

CONCLUSIONS

Simultaneous intravitreal DEX and aflibercept achieved non-inferior improvement of visual and anatomic outcomes compared with aflibercept alone for DME, but exhibited a significantly longer treatment interval and superior visual outcome in pseudophakic eyes. This therapeutic approach is considered a valid strategy for treating DME in the era of COVID-19.

Clinical manifestation and current therapeutics in X-juvenile retinoschisis

X-linked juvenile retinoschisis (XLRS) is one of the common early-onset hereditary retinal degenerative diseases in men. The common symptoms of XLRS range from mild to severe central vision loss and radial stripes created by the fovea, the division of the inner layer of the retina in the peripheral retina and the significant decrease in b-wave amplitude (ERG). Retinoschisin, the 224-amino-acid protein product of the retinoschisis 1 (RS1) gene, contains a discoid domain as the primary structural unit, an N-terminal cleavable signal sequence, and an oligomerization-area component. Retinoschisin is a homo-octamer complex with disulfide links that are released by retinal cells. It helps preserve the retina's integrity by binding to the surface of photoreceptors and bipolar cells. As a recessive genetic disease, XLRS was usually treated by prescribing low vision aids in most clinical cases. A gene replacement therapy based on adeno-associated virus vectors was initiated and showed a breakthrough in treating XLRS in 2014. Understanding the revolution of gene therapy for treating XLRS may accelerate its development and make this gene therapy the template for developing therapeutics against other inherited retinal diseases.

Recovery of visual field defects following vitrectomy for proliferative diabetic retinopathy: A case report

RATIONALE

Proliferative diabetic retinopathy (PDR) may lead to severe visual impairment, and visual field (VF) loss in such patients has been reported. Vitrectomy is performed in PDR cases complicated with either vitreous hemorrhage or tractional retinal detachment to restore their visual acuity. However, its effect on VF defects is limited in data. Herein, we report the recovery of VF defects following vitrectomy in a patient with PDR.

PATIENT CONCERNS

A 25-year-old female with bilateral PDR and vitreous hemorrhage received 2 monthly intravitreal injections of aflibercept in both eyes. Six months after her last injection, she presented with fibrovascular membrane formation in both eyes and VF defects of -9.02 dB and -20.05 dB in the right and left eye, respectively.

DIAGNOSES

Proliferative diabetic retinopathy in both eyes.

INTERVENTIONS

The patient underwent vitrectomy for her left eye.

OUTCOMES

Although her visual acuity did not improve as expected, results from the Humphrey visual field analyzer showed notably improvement of her left eye (-9.05 dB) after the surgery.

LESSONS

Vitrectomy potentially allows recovery of VF defects in patients with PDR.

Modifications of intravitreal injections in response to the COVID-19 pandemic

The Coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented disruption to the normal operation of the healthcare system. On a worldwide scale, hospitals suspended nonurgent surgeries and outpatient visits to downsize clinical loadings to redistribute manpower to counteract the pandemic's impact. So far, there is no evidence-based guideline defining a clear line between urgent and nonurgent indications of intravitreal injections (IVI). Herein, we aimed to summarize IVI algorithm modifications and discuss the patient prioritization according to medical needs in the hostile environment in the COVID crisis. Assessing current literature, we found that neovascular age-related macular degeneration is considered the utmost priority among conditions that require IVI. Other conditions assigned with a high priority include monocular or quasi-monocular patients (only one eye > 20/40), neovascular glaucoma, and new patients with significant vision loss. Although patients with central retinal vein occlusion and proliferative diabetic retinopathy are not advised to delay treatments, we found no consistent evidence that correlated with a worse outcome. Diabetic macular edema and branch retinal vein occlusion patients undertaking treatment delay should be regularly followed up every 2 to 3 months. Serving as the principle of management behind the algorithm modifications, the reduction of both patient visit and IVI therapy counts should be reckoned together with the risk of permanent visual loss and COVID infection.

Mitochondrial transport mediates survival of retinal ganglion cells in affected LHON patients

The mutations in the genes encoding the subunits of complex I of the mitochondrial electron transport chain are the most common cause of Leber's hereditary optic neuropathy (LHON), a maternal hereditary disease characterized by retinal ganglion cell (RGC) degeneration. The characteristics of incomplete penetrance indicate that nuclear genetic and environmental factors also determine phenotypic expression of LHON. Therefore, further understanding of the role of mutant mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit proteins and nuclear genetic factors/environmental effects in the etiology of LHON is needed. In this study, we generated human-induced pluripotent stem cells (hiPSCs) from healthy control, unaffected LHON mutation carrier, and affected LHON patient. hiPSC-derived RGCs were used to study the differences between affected and unaffected carriers of mitochondrial DNA point mutation m.11778G > A in the MT-ND4 gene. We found that both mutated cell lines were characterized by increase in reactive oxygen species production, however, only affected cell line had increased levels of apoptotic cells. We found a significant increase in retrograde mitochondria and a decrease in stationary mitochondria in the affected RGC axons. In addition, the messenger RNA and protein levels of KIF5A in the LHON-affected RGCs were significantly reduced. Antioxidant N-acetyl-L-cysteine could restore the expression of KIF5A and the normal pattern of mitochondrial movement in the affected RGCs. To conclude, we found essential differences in the mutually dependent processes of oxidative stress, mitochondrial transport and apoptosis between two LHON-specific mutation carrier RGC cell lines, asymptomatic carrier and disease-affected, and identified KIF5A as a central modulator of these differences.

Application of artificial intelligence-driven endoscopic screening and diagnosis of gastric cancer

The landscape of gastrointestinal endoscopy continues to evolve as new technologies and techniques become available. The advent of image-enhanced and magnifying endoscopies has highlighted the step toward perfecting endoscopic screening and diagnosis of gastric lesions. Simultaneously, with the development of convolutional neural network, artificial intelligence (AI) has made unprecedented breakthroughs in medical imaging, including the ongoing trials of computer-aided detection of colorectal polyps and gastrointestinal bleeding. In the past demi-decade, applications of AI systems in gastric cancer have also emerged. With AI’s efficient computational power and learning capacities, endoscopists can improve their diagnostic accuracies and avoid the missing or mischaracterization of gastric neoplastic changes. So far, several AI systems that incorporated both traditional and novel endoscopy technologies have been developed for various purposes, with most systems achieving an accuracy of more than 80%. However, their feasibility, effectiveness, and safety in clinical practice remain to be seen as there have been no clinical trials yet. Nonetheless, AI-assisted endoscopies shed light on more accurate and sensitive ways for early detection, treatment guidance and prognosis prediction of gastric lesions. This review summarizes the current status of various AI applications in gastric cancer and pinpoints directions for future research and clinical practice implementation from a clinical perspective.

Identification of Novel Genomic-Variant Patterns of OR56A5, OR52L1, and CTSD in Retinitis Pigmentosa Patients by Whole-Exome Sequencing

Inherited retinal dystrophies (IRDs) are rare but highly heterogeneous genetic disorders that affect individuals and families worldwide. However, given its wide variability, its analysis of the driver genes for over 50% of the cases remains unexplored. The present study aims to identify novel driver genes, disease-causing variants, and retinitis pigmentosa (RP)-associated pathways. Using family-based whole-exome sequencing (WES) to identify putative RP-causing rare variants, we identified a total of five potentially pathogenic variants located in genes OR56A5, OR52L1, CTSD, PRF1, KBTBD13, and ATP2B4. Of the variants present in all affected individuals, genes OR56A5, OR52L1, CTSD, KBTBD13, and ATP2B4 present as missense mutations, while PRF1 and CTSD present as frameshift variants. Sanger sequencing confirmed the presence of the novel pathogenic variant PRF1 (c.124_128del) that has not been reported previously. More causal-effect or evidence-based studies will be required to elucidate the precise roles of these SNPs in the RP pathogenesis. Taken together, our findings may allow us to explore the risk variants based on the sequencing data and upgrade the existing variant annotation database in Taiwan. It may help detect specific eye diseases such as retinitis pigmentosa in East Asia.

An Update on Gene Therapy for Inherited Retinal Dystrophy: Experience in Leber Congenital Amaurosis Clinical Trials

Inherited retinal dystrophies (IRDs) are a group of rare eye diseases caused by gene mutations that result in the degradation of cone and rod photoreceptors or the retinal pigment epithelium. Retinal degradation progress is often irreversible, with clinical manifestations including color or night blindness, peripheral visual defects and subsequent vision loss. Thus, gene therapies that restore functional retinal proteins by either replenishing unmutated genes or truncating mutated genes are needed. Coincidentally, the eye’s accessibility and immune-privileged status along with major advances in gene identification and gene delivery systems heralded gene therapies for IRDs. Among these clinical trials, voretigene neparvovec-rzyl (Luxturna), an adeno-associated virus vector-based gene therapy drug, was approved by the FDA for treating patients with confirmed biallelic RPE65 mutation-associated Leber Congenital Amaurosis (LCA) in 2017. This review includes current IRD gene therapy clinical trials and further summarizes preclinical studies and therapeutic strategies for LCA, including adeno-associated virus-based gene augmentation therapy, 11-cis-retinal replacement, RNA-based antisense oligonucleotide therapy and CRISPR-Cas9 gene-editing therapy. Understanding the gene therapy development for LCA may accelerate and predict the potential hurdles of future therapeutics translation. It may also serve as the template for the research and development of treatment for other IRDs.

Xeno-free cryopreservation of adherent retinal pigmented epithelium yields viable and functional cells in vitro and in vivo

Age-related macular degeneration (AMD) is the primary cause of blindness in adults over 60 years of age, and clinical trials are currently assessing the therapeutic potential of retinal pigmented epithelial (RPE) cell monolayers on implantable scaffolds to treat this disease. However, challenges related to the culture, long-term storage, and long-distance transport of such implants currently limit the widespread use of adherent RPE cells as therapeutics. Here we report a xeno-free protocol to cryopreserve a confluent monolayer of clinical-grade, human embryonic stem cell-derived RPE cells on a parylene scaffold (REPS) that yields viable, polarized, and functional RPE cells post-thaw. Thawed cells exhibit ≥ 95% viability, have morphology, pigmentation, and gene expression characteristic of mature RPE cells, and secrete the neuroprotective protein, pigment epithelium-derived factor (PEDF). Stability under liquid nitrogen (LN₂) storage has been confirmed through one year. REPS were administered immediately post-thaw into the subretinal space of a mammalian model, the Royal College of Surgeons (RCS)/nude rat. Implanted REPS were assessed at 30, 60, and 90 days post-implantation, and thawed cells demonstrate survival as an intact monolayer on the parylene scaffold. Furthermore, immunoreactivity for the maturation marker, RPE65, significantly increased over the post-implantation period in vivo, and cells demonstrated functional attributes similar to non-cryopreserved controls. The capacity to cryopreserve adherent cellular therapeutics permits extended storage and stable transport to surgical sites, enabling broad distribution for the treatment of prevalent diseases such as AMD.

Primary Signet Ring Cell/Histiocytoid Carcinoma of the Eyelid: Somatic Mutations in CDH1 and Other Clinically Actionable Mutations Imply Early Use of Targeted Agents

Primary signet ring cell/histiocytoid carcinoma of the eyelid is a rare ocular malignancy and its diagnosis is often delayed. This neoplasm presents as an insidious, diffusely infiltrative mass in the periocular area that later infiltrates the orbit. An exenteration is usually indicated; however, nearly one-third of patients develop local recurrence or metastasis. Morphologically, it resembles signet ring cell carcinoma of the stomach and breast, raising the possibility of mutations in CDH1, the gene encoding E-cadherin. To determine whether primary signet ring cell/histiocytoid carcinoma harbors the CDH1 mutation or other actionable mutations, we analyzed the tumor tissue via next-generation sequencing. We identified only one case of primary signet ring cell carcinoma of the eyelid with adequate DNA quality for sequencing from the pathological archive during the period 2000 to 2020. A comprehensive evaluation including histopathology, immunohistochemistry, and next-generation sequencing assay was performed on tumor tissue. Immunohistochemically, the tumor exhibited E-cadherin membranous staining with the aberrant cytoplasmic staining of β-catenin. Using next-generation sequencing, we demonstrated the mutation in the CDH1 gene. In addition, other clinically actionable mutations including ERBB2 and PIK3CA were also detected. The alterations in other actionable genes indicate a need for larger studies to evaluate the pathogenesis and potential therapies for primary signet ring cell/histiocytoid carcinoma of the eyelid.

Expression of Endogenous Angiotensin-Converting Enzyme 2 in Human Induced Pluripotent Stem Cell-Derived Retinal Organoids

Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.

Smartphone-based diabetic macula edema screening with an offline artificial intelligence

BACKGROUND

Diabetic macular edema (DME) is a sight-threatening condition that needs regular examinations and remedies. Optical coherence tomography (OCT) is the most common used examination to evaluate the structure and thickness of the macula, but the software in the OCT machine does not tell the clinicians whether DME exists directly. Recently, artificial intelligence (AI) is expected to aid in diagnosis generation and therapy selection. We thus develop a smartphone-based offline AI system that provides diagnostic suggestions and medical strategies through analyzing OCT images from diabetic patients at the risk of developing DME.

METHODS

DME patients receiving treatments in 2017 at Taipei Veterans General Hospital were included in this study. We retrospectively collected the OCT images of these patients from January 2008 to July 2018. We established the AI model based on MobileNet architecture to classify the OCT images conditions. The confusion matrix has been applied to present the performance of the trained AI model.

RESULTS

Based on the convolutional neural network with the MobileNet model, our AI system achieved a high DME diagnostic accuracy of 90.02%, which is comparable to other AI systems such as InceptionV3 and VGG16. We further developed a mobile-application based on this AI model available at https://aicl.ddns.net/DME.apk.

CONCLUSION

We successful integrated an AI model into the mobile device to provide an offline method to provide the diagnosis for quickly screening the risk of developing DME. With the offline property, our model could help those nonophthalmological healthcare providers in offshore islands or underdeveloped countries.

Optical coherence tomography-based diabetic macula edema screening with artificial intelligence

BACKGROUND

Optical coherence tomography (OCT) is considered as a sensitive and noninvasive tool to evaluate the macular lesions. In patients with diabetes mellitus (DM), the existence of diabetic macular edema (DME) can cause significant vision impairment and further intravitreal injection (IVI) of anti-vascular endothelial growth factor (VEGF) is needed. However, the increasing number of DM patients makes it a big burden for clinicians to manually determine whether DME exists in the OCT images. The artificial intelligence (AI) now enormously applied to many medical territories may help reduce the burden on clinicians.

METHODS

We selected DME patients receiving IVI of anti-VEGF or corticosteroid at Taipei Veterans General Hospital in 2017. All macular cross-sectional scan OCT images were collected retrospectively from the eyes of these patients from January 2008 to July 2018. We further established AI models based on convolutional neural network architecture to determine whether the DM patients have DME by OCT images.

RESULTS

Based on the convolutional neural networks, InceptionV3 and VGG16, our AI system achieved a high DME diagnostic accuracy of 93.09% and 92.82%, respectively. The sensitivity of the VGG16 and InceptionV3 models was 96.48% and 95.15%., respectively. The specificity was corresponding to 86.67% and 89.63% for VGG16 and InceptionV3, respectively. We further developed an OCT-driven platform based on these AI models.

CONCLUSION

We successfully set up AI models to provide an accurate diagnosis of DME by OCT images. These models may assist clinicians in screening DME in DM patients in the future.

The era of artificial intelligence-based individualized telemedicine is coming

Artificial intelligence (AI), Internet of Things (IoT), and telemedicine are deeply involved in our daily life and have also been extensively applied in the medical field, especially in ophthalmology. Clinical ophthalmologists are required to perform a vast array of image exams and analyze images containing complicated information, which allows them to diagnose the disease type and grade, make a decision on remedy, and predict treatment outcomes. AI has a great potential to assist ophthalmologists in their daily routine of image analysis and relieve their work burden. However, in spite of these prospects, the application of AI may also be controversial and associated with several legal, ethical, and sociological concerns. In spite of these issues, AI has indeed become an irresistible trend and is widely used by medical specialists in their daily routines in what we can call now, the era of AI. This review will encompass those issues and focus on recent research on the AI application in ophthalmology and telemedicine.

Development of polydimethylsiloxane-based biomimetic scaffolds with cylinder micropillars for retinal pigment epithelial cell cultivation

BACKGROUND

Age-related macular degeneration (AMD) is one of the leading causes of vision loss. Once the retinal pigment epithelium (RPE) layers are destroyed, the poor visual acuity and recognition are generally irreversible. Cell therapy that possesses enormous potential in regenerative medicine may provide an alternative treatment for several incurable diseases such as AMD. In this study, we developed an innovative polydimethylsiloxane (PDMS)-based biomimetic scaffolds with cylinder micropillars for the cultivation of induced pluripotent stem cell-derived RPEs (iPSC-RPEs). RPEs were cultured on the PDMS-based biomimetic scaffolds and validated the cells gene expression.

METHODS

The biomimetic PDMS scaffold was fabricated through spin coating and lithography method. It was further modified on surface with biomolecules to improve cell affinity and stability. The iPSC-RPEs were seeded on the scaffold and analyzed with characteristic gene expression.

RESULTS

PDMS biomimetic scaffold was analyzed with Fourier transform infrared spectroscopy and proved its chemical composition. iPSC-RPEs demonstrated confluent cell monolayer on the scaffold and maintained RPE-specific gene expression, which proved the PDMS-based biomimetic scaffold to be supportive for iPSC-RPEs growth.

CONCLUSION

The PDMS interface allowed regular growth of iPSC-RPEs and the design of cylinder micropillars further provided the bioscaffold high motion resistance may improve the engraftment stability of iPSC-RPEs after transplantation. Taken together, this innovative PDMS-based biomimetic scaffold may serve as an ideal interface for in vitro iPSC-RPE cultivation and subsequent transplantation in vivo. This novel device exhibits better bioavailability than conventional injection of donor cells and may be an alternative option for the treatment of AMD.

Changes in the Systemic Expression of Sirtuin-1 and Oxidative Stress after Intravitreal Anti-Vascular Endothelial Growth Factor in Patients with Retinal Vein Occlusion

OBJECTIVES

Retinal vein occlusions (RVO) are associated with systemic risk factors. However, the ocular occlusive events might also influence a patient's systemic condition. This study tried to investigate serum biomarkers associated with oxidative stress, before and after intravitreal anti-vascular endothelial growth factor (aVEGF) therapy in patients with RVOs.

METHODS

Newly-onset RVO patients were categorized into two groups: comorbid with macular edema requiring aVEGF therapy (treatment group) and no edema (observation group). Age and sex-matched patients (who received cataract surgery) were included as the control group. Intravitreal ranibizumab with a pro-re-nata regimen were administered. Serum samples were collected prior to treatment, at 6 and 12 months after therapy/observation and were collected once before controls who received cataract surgery. mRNA expression of sirtuin-1, its downstream genes, anti-oxidative biomarkers, and proinflammatory cytokines were measured.

RESULTS

There were 32, 26, and 34 patients enrolled in the treatment, observation, and control groups, respectively. The expressions of sirtuin-1 and its downstream genes were significantly lower in patients with RVO compared with the control group. Sirtuin-1 gene expression increased after 1 year of aVEGF therapy in the treatment group but remained unchanged in the observation group. Biomarkers of oxidative stress and proinflammatory cytokines were reduced after 1 year of aVEGF therapy. These biomarkers remained with no changes in the observation group.

CONCLUSIONS

Our study showed that the systemic oxidative stress increased in RVO patients. The aVEGF therapy could alter the gene expression of anti-oxidative proteins and reduce systemic oxidative stress in these patients.

A novelty route for smartphone-based artificial intelligence approach to ophthalmic screening

Artificial intelligence (AI) has been widely applied in the medical field and achieved enormous milestones in helping specialists to make diagnosis and remedy decisions, particularly in the field of eye diseases and ophthalmic screening. With the development of AI-based systems, the enormous hardware and software resources are required for optimal performance. In reality, there are many places on the planet where such resources are highly limited. Hence, the smartphone-based AI systems can be used to provide a remote control route to quickly screen eye diseases such as diabetic-related retinopathy or diabetic macular edema. However, the performance of such mobile-based AI systems is still uncharted territory. In this article, we discuss the issues of computing resource consumption and performance of the mobile device-based AI systems and highlight recent research on the feasibility and future potential of application of the mobile device-based AI systems in telemedicine.

Image quality and diagnostic accuracy of a handheld nonmydriatic fundus camera: Feasibility of a telemedical approach in screening retinal diseases

BACKGROUND

A suitable fundus camera for telemedicine screening can expand the scale of eye care service. The purpose of this study was to compare a handheld nonmydriatic digital fundus camera and a conventional mydriatic fundus camera according to the image quality of their photographs and usability of those photographs to accurately diagnose various retinal diseases.

METHODS

A handheld nonmydriatic fundus camera and conventional fundus camera were used to take fundus photographs of outpatients at an ophthalmic clinic before and after pupillary dilation. Image quality and diagnostic agreement of the photos were graded by two masked and experienced retinal specialists.

RESULTS

A total of 867 photographs of 393 eyes of 200 patients were collected. Approximately 80% of photos taken under nonmydriasis status using the handheld nonmydriatic fundus camera had good (55.7%) or excellent (22.7%) image quality. The overall agreement of diagnoses between the doctors was more than 90%. When the handheld nonmydriatic fundus camera was used after mydriasis, the proportion of images with good (45%) or excellent (49.7%) quality reached 94.7% and diagnostic agreement was 93.4%. Lens opacity was associated with the quality of images obtained using the handheld camera (p = 0.041), and diagnosis disagreement for handheld camera images was associated with preexisting diabetes diagnosis (p = 0.009). Approximately 40% of patients expressed preference for use of the handheld nonmydriatic camera.

CONCLUSION

This study demonstrated the effectiveness of the handheld nonmydriatic fundus camera in clinical practice and its feasibility for telemedicine screening of retinal diseases.

Modulation of osmotic stress-induced TRPV1 expression rescues human iPSC-derived retinal ganglion cells through PKA

Background

Transient receptor potential vanilloid 1 (TRPV1), recognized as a hyperosmolarity sensor, is a crucial ion channel involved in the pathogenesis of neural and glial signaling. Recently, TRPV1 was determined to play a role in retinal physiology and visual transmission. In this study, we sought to clarify the role of TRPV1 and the downstream pathway in the osmotic stress-related retina ganglion cell (RGC) damage.

Methods

First, we modified the RGC differentiation protocol to obtain a homogeneous RGC population from human induced pluripotent stem cells (hiPSCs). Subsequently, we induced high osmotic pressure in the hiPSC-derived RGCs by administering NaCl solution and observed the behavior of the TRPV1 channel and its downstream cascade.

Results

We obtained a purified RGC population from the heterogeneous retina cell population using our modified method. Our findings revealed that TRPV1 was activated after 24 h of NaCl treatment. Upregulation of TRPV1 was noted with autophagy and apoptosis induction. Downstream protein expression analysis indicated increased phosphorylation of CREB and downregulated brain-derived neurotrophic factor (BDNF). However, hyperosmolarity-mediated defective morphological change and apoptosis of RGCs, CREB phosphorylation, and BDNF downregulation were abrogated after concomitant treatment with the PKA inhibitor H89.

Conclusion

Collectively, our study results indicated that the TRPV1–PKA pathway contributed to cellular response under high levels of osmolarity stress; furthermore, the PKA inhibitor had a protective effect on RGCs exposed to this stress. Therefore, our findings may assist in the treatment of eye diseases involving RGC damage.

Priority options of anti-vascular endothelial growth factor agents in wet age-related macular degeneration under the National Health Insurance Program

BACKGROUND

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide, for which intravitreal injection of anti-vascular endothelial growth factor (VEGF) is the primary treatment option. The purpose of the current study was to investigate the prioritization of anti-VEGF agents for wet AMD under the National Health Insurance (NHI) Program, and their clinical outcomes.

METHODS

Patients who were diagnosed with active choroidal neovascularization caused by AMD, and who met the criteria for reimbursement for anti-VEGF therapy by the NHI program in Taiwan between August 1, 2014 and May 31, 2015, were included in the study. Factors potentially influencing the choice of treatment agent were analyzed, and clinical outcomes were compared between the two different agents and their protocols.

RESULTS

A total of 166 treatment applications in 166 eyes from 159 patients were enrolled in the study. Age, laterality, presence of retinal pigment epithelial detachment, history of hypertension, coronary artery disease, and cerebral vascular accidents were significantly associated with the selection of the anti-VEGF agent. Treatment patterns and clinical outcomes were similar between the patients treated with ranibizumab and those treated with aflibercept. Significantly fewer injections were given during the follow-up period in those treated with aflibercept.

CONCLUSION

Under the restrictive insurance program in Taiwan, more patients and ophthalmologists chose to treat wet AMD using aflibercept. However, in clinical practice, no significant differences in efficacy or clinical outcomes were found between the patients treated with ranibizumab and those treated with aflibercept.

Nanomedicine-based Curcumin Approach Improved ROS Damage in Best Dystrophy-specific Induced Pluripotent Stem Cells

Best dystrophy (BD), also termed best vitelliform macular dystrophy (BVMD), is a juvenile-onset form of macular degeneration and can cause central visual loss. Unfortunately, there is no clear definite therapy for BD or improving the visual function on this progressive disease. The human induced pluripotent stem cell (iPSC) system has been recently applied as an effective tool for genetic consultation and chemical drug screening. In this study, we developed patient-specific induced pluripotent stem cells (BD-iPSCs) from BD patient-derived dental pulp stromal cells and then differentiated BD-iPSCs into retinal pigment epithelial cells (BD-RPEs). BD-RPEs were used as an expandable platform for in vitro candidate drug screening. Compared with unaffected sibling-derived iPSC-derived RPE cells (Ctrl-RPEs), BD-RPEs exhibited typical RPE-specific markers with a lower expression of the tight junction protein ZO-1 and Bestrophin-1 (BEST1), as well as reduced phagocytic capabilities. Notably, among all candidate drugs, curcumin was the most effective for upregulating both the BEST1 and ZO-1 genes in BD-RPEs. Using the iPSC-based drug-screening platform, we further found that curcumin can significantly improve the mRNA expression levels of Best gene in BD-iPSC-derived RPEs. Importantly, we demonstrated that curcumin-loaded PLGA nanoparticles (Cur-NPs) were efficiently internalized by BD-RPEs. The Cur-NPs-based controlled release formulation further increased the expression of ZO-1 and Bestrophin-1, and promoted the function of phagocytosis and voltage-dependent calcium channels in BD-iPSC-derived RPEs. We further demonstrated that Cur-NPs enhanced the expression of antioxidant enzymes with a decrease in intracellular ROS production and hydrogen peroxide-induced oxidative stress. Collectively, these data supported that Cur-NPs provide a potential cytoprotective effect by regulating the anti-oxidative abilities of degenerated RPEs. In addition, the application of patient-specific iPSCs provides an effective platform for drug screening and personalized medicine in incurable diseases.

First implantation of retinal prosthesis in a patient with high myopia after surgery and rehabilitation program in Taiwan

The implantation of the Argus II retinal prosthesis system in a 54-year-old woman with retinitis pigmentosa who presented with an eye of long axial length at 26.82 mm was successful. Postoperative examination revealed a gap of 700 µm between the electrode array and the retina, which caused decreased visual perception. A modified strategy with quad and quinary electrode stimulation was introduced to generate higher perceptual thresholds. The patient experienced visual functional changes during the first half of the year after surgery, although no remarkable difference was observed in terms of implant-retina distance. Fibrosis around the tack developed and extended between the gap with the retina elevated from the tack toward the center array, 8 months after the surgery. Schisis of the retina developed and filled the gap, resulting in decreased threshold, and the strategy was then shifted back to single electrode stimulation mode. Rehabilitation program is an evolving process that depends on the distance between the array and the retina in the eye with staphyloma. This study first showed the implantation in a patient with high myopia who presented with long axial length after surgery and rehabilitation program in Taiwan.

Glutamate Stimulation Dysregulates AMPA Receptors-Induced Signal Transduction Pathway in Leber's Inherited Optic Neuropathy Patient-Specific hiPSC-Derived Retinal Ganglion Cells

The mitochondrial genetic disorder, Leber’s hereditary optic neuropathy (LHON), is caused by a mutation in MT-ND4 gene, encoding NADH dehydrogenase subunit 4. It leads to the progressive death of retinal ganglion cells (RGCs) and causes visual impairment or even blindness. However, the precise mechanisms of LHON disease penetrance and progression are not completely elucidated. Human-induced pluripotent stem cells (hiPSCs) offer unique opportunities to investigate disease-relevant phenotypes and regulatory mechanisms underlying LHON pathogenesis at the cellular level. In this study, we successfully generated RGCs by differentiation of LHON patient-specific hiPSCs. We modified the protocol of differentiation to obtain a more enriched population of single-cell RGCs for LHON study. Based on assessing morphology, expression of specific markers and electrophysiological activity, we found that LHON-specific hiPSC-derived were more defective in comparison with normal wild-type RGCs. Based on our previous study, whereby by using microarray analysis we identified that the components of glutamatergic synapse signaling pathway were significantly downregulated in LHON-specific RGCs, we focused our study on glutamate-associated α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors. We found that the protein expression levels of the subunits of the AMPA receptor, GluR1 and GluR2, and their associated scaffold proteins were decreased in LHON-RGCs. By performing the co-immunoprecipitation assay, we found several differences in the efficiencies of interaction between AMPA subunits and scaffold proteins between normal and LHON-specific RGCs.

Histopathologic Assessment of Optic Nerves and Retina From a Patient With Chronically Implanted Argus II Retinal Prosthesis System

Purpose

To characterize histologic changes in the optic nerve and the retina of an end-stage retinitis pigmentosa (RP) patient after long-term implantation with the Argus II retinal prosthesis system.

Methods

Serial cross sections from the patient's both eyes were collected postmortem 6 years after implantation. Optic nerve from both eyes were morphometrically analyzed and compared. Retina underneath and outside the array was analyzed and compared with corresponding regions in the fellow eye.

Results

Although the optic nerve of the implant eye demonstrated significantly more overall atrophy than the fellow eye (P < 0.01), the temporal quadrant that retinotopically corresponded to the location of the array did not show additional damage. The total neuron count of the macular area was not significantly different between the two eyes, but the tack locations and their adjacent areas showed significantly fewer neurons than other perimacular areas. There was an increased expression of glial fibrillary acidic protein (GFAP) throughout the retina in the implant eye versus the fellow eye, but there was no significant difference in the cellular retinaldehyde-binding protein (CRALBP) expression. Except for the revision tack site, no significant increase of inflammatory reaction was detected in the implant eye.

Conclusion

Long-term implantation and electrical stimulation with an Argus II retinal prosthesis system did not result in significant tissue damage that could be detected by a morphometric analysis.

Translational Relevance

This study supports the long-term safety of the Argus II device and encourages further development of bioelectronics devices at the retina-machine interface.

Establishment of vestibular function multimodality platform

BACKGROUND

The technology of using inertial measurement units (IMUs) to detect motions in different body segments has drawn enormous attention to research and industry. In our previous research, we have applied IMUs in evaluating and treating patients with vestibular hypofunction. Furthermore, according to the research, when a person's head rotates over 60° on either side in the horizontal plane, and desires to focus vision on any targets, then the function of gaze shift comes in to operation. Herein, we aimed to use IMUs to build up a system to evaluate vestibular ocular reflex (VOR) during gaze shifting maneuver.

METHODS

In this study, we developed a platform, which combines the features of gaze shift and computerized dynamic visual acuity (cDVA), called the gaze shift DVA (gsDVA) platform. The gsDVA platform measures the orientations of the subject's head by IMU, and executed the evaluation according to the algorithm that was developed by us. Finally, we used the VICON system to validate the performance of gsDVA platform.

RESULTS

The performance of the accuracy was 2.41° ± 1.08°, the maximal sensor error was within 4.25°, and highly correlated between our platform and VICON (p < 0.05, R = 0.99). The intraclass correlation coefficient (ICC) of between-day and within-day was 0.984 and 0.999, respectively. Furthermore, the platform not only executed the evaluation automatically but also recorded other information besides the head orientation, such as rotation speed, rotation time, reaction time, and visual acuity.

CONCLUSION

In this study, we demonstrated the utility of vestibular evaluation, and this platform can help to clarify the relationship between gaze shift and VOR. This methodology is useful and can be applied efficiently to different disease groups for interactive evaluation and rehabilitation programs.

Artificial intelligence-based decision-making for age-related macular degeneration

Artificial intelligence (AI) based on convolutional neural networks (CNNs) has a great potential to enhance medical workflow and improve health care quality. Of particular interest is practical implementation of such AI-based software as a cloud-based tool aimed for telemedicine, the practice of providing medical care from a distance using electronic interfaces.

Methods: In this study, we used a dataset of labeled 35,900 optical coherence tomography (OCT) images obtained from age-related macular degeneration (AMD) patients and used them to train three types of CNNs to perform AMD diagnosis.

Results: Here, we present an AI- and cloud-based telemedicine interaction tool for diagnosis and proposed treatment of AMD. Through deep learning process based on the analysis of preprocessed optical coherence tomography (OCT) imaging data, our AI-based system achieved the same image discrimination rate as that of retinal specialists in our hospital. The AI platform's detection accuracy was generally higher than 90% and was significantly superior (p < 0.001) to that of medical students (69.4% and 68.9%) and equal (p = 0.99) to that of retinal specialists (92.73% and 91.90%). Furthermore, it provided appropriate treatment recommendations comparable to those of retinal specialists.

Conclusions: We therefore developed a website for realistic cloud computing based on this AI platform, available at https://www.ym.edu.tw/~AI-OCT/. Patients can upload their OCT images to the website to verify whether they have AMD and require treatment. Using an AI-based cloud service represents a real solution for medical imaging diagnostics and telemedicine.

Treatment patterns in diabetic macular edema in Taiwan: a retrospective chart review

Objectives

To characterize diabetic macular edema (DME) treatment patterns in Taiwan and examine their impact on health care resource utilization and visual and anatomic outcomes.

Methods

Retrospective, observational cohort study of longitudinal data from medical records of five hospital ophthalmology clinics. Patients with type 2 diabetes and DME who received ≥1 laser treatment or pharmacotherapy (intravitreal/subtenon corticosteroids and/or intravitreal anti-vascular endothelial growth factor [VEGF] agents) between January 2012 and December 2013 (index period) and attended ≥1 follow-up visit after the first treatment during that period were identified (prevalent population, N=431). In addition, a subset that received no anti-VEGFs before 2012 (anti-VEGF-naïve population, N=77) was analyzed. Outcome measures were change in DME treatment distribution between January 2009 and December 2014 and health care resource utilization over up to 3 years from the first DME treatment received in the index period (prevalent population), mean number of anti-VEGF injections and change from baseline in visual acuity and central macular thickness over 12 months (anti-VEGF-naïve population).

Results

Between 2009 and 2014, laser treatment use declined, overall use of anti-VEGFs increased, and bevacizumab use decreased proportionately as ranibizumab use increased. Patients receiving corticosteroids and anti-VEGFs in the first 6 months post-index had greater health care resource utilization than those treated with laser, corticosteroids, or anti-VEGF alone (P<0.0001, cross-cohort comparison). Among anti-VEGF-naïve patients, 69% received one to four anti-VEGF injections in the first year post-index. Overall, visual acuity improvement from baseline was minimal at 1 year (0.4 letters, observed data; 0.1 letters, last observation carried forward), and modest central macular thickness reduction (28 µm [last observation carried forward]) was detected.

Conclusion

In Taiwanese clinics, DME treatment patterns have shifted from use of laser to anti-VEGFs (with higher health care resource utilization); however, few patients receive anti-VEGF injections at the frequency reported in landmark trials, consistent with poorer visual outcomes. Effective alternative treatments with lower treatment burden should be considered.

Noninfectious uveitis in the Asia-Pacific region

Uveitis is a sight-threatening disease. Up to 35% of patients may have impaired vision. Inflammation of the uvea tissue has more than 60 etiologies. Previous reports have shown that 20-40% of uveitis cases were noninfectious. Some of them may be associated with systemic rheumatological and autoimmune diseases but some may affect the eyes only. The epidemiology and clinical situations of some specific uveitis entities vary worldwide because they are influenced by genetic, ethnic, environmental, and socioeconomic factors. The Asia-Pacific region comprises more than 30 countries. Epidemiology and patterns of uveitis vary greatly in this region. However, some uveitis entities, such as Behcet's disease, sarcoidosis, and Vogt-Koyanagi-Harada disease, are more common in this region. Many studies on the epidemiology, risk factors, and immune pathogenesis of this disease have been conducted. In this article, we review the epidemiology of noninfectious uveitis and special situations of these three uveitis entities in the Asia-Pacific region.

A new immunodeficient retinal dystrophic rat model for transplantation studies using human-derived cells

PURPOSE

To create new immunodeficient Royal College of Surgeons (RCS) rats by introducing the defective MerTK gene into athymic nude rats.

METHODS

Female homozygous RCS (RCS-p+/RCS-p+) and male nude rats (Hsd:RH-Foxn1^mu, mutation in the foxn1 gene; no T cells) were crossed to produce heterozygous F1 progeny. Double homozygous F2 progeny obtained by crossing the F1 heterozygotes was identified phenotypically (hair loss) and genotypically (RCS-p+ gene determined by PCR). Retinal degenerative status was confirmed by optical coherence tomography (OCT) imaging, electroretinography (ERG), optokinetic (OKN) testing, superior colliculus (SC) electrophysiology, and by histology. The effect of xenografts was assessed by transplantation of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) and human-induced pluripotent stem cell-derived RPE (iPS-RPE) into the eye. Morphological analysis was conducted based on hematoxylin and eosin (H&E) and immunostaining. Age-matched pigmented athymic nude rats were used as control.

RESULTS

Approximately 6% of the F2 pups (11/172) were homozygous for RCS-p+ gene and Foxn1^mu gene. Homozygous males crossed with heterozygous females resulted in 50% homozygous progeny for experimentation. OCT imaging demonstrated significant loss of retinal thickness in homozygous rats. H&E staining showed photoreceptor thickness reduced to 1-3 layers at 12 weeks of age. Progressive loss of visual function was evidenced by OKN testing, ERG, and SC electrophysiology. Transplantation experiments demonstrated survival of human-derived cells and absence of apparent immune rejection.

CONCLUSIONS

This new rat animal model developed by crossing RCS rats and athymic nude rats is suitable for conducting retinal transplantation experiments involving xenografts.

Acoustic waves improves retroviral transduction in human retinal stem cells

BACKGROUNDS

The plasticity of retinal stem cells (RSCs), a type of cells that can differentiate into neuron cells and photoreceptor cells, endows them with potential therapeutic properties that can be applied to regenerative medicine. Gene modification of these stem cells before trans-differentiation and transplantation enhances their survival and increases their therapeutic function. The different ways to effectively deliver gene into RSCs are still discussed. This study aimed to use the acoustic waves to improve the efficacy of gene delivery for RSCs.

METHODS

RSCs were obtained from non-fetal human ocular pigmented ciliary margin tissues. The enhanced green fluorescent protein-encoded murine stem cell retroviruses (MSCV) were prepared and used to infect RSCs. Glass chambers containing RSCs, retroviruses, and various concentrations of polybrene (0, 0.8, 2, 4 and 8 μg/mL) were exposed under 20 or 25 Vp-p ultrasonic standing wave fields (USWF) for 5 min. The percentage of green fluorescent protein positive cells in each sample was calculated and compared to test the efficacy of gene transduction.

RESULTS

Our results showed that the efficiency of gene transduction by MSCV infection was enhanced following the concentration of polybrene and the energy of USWF. The percentage of green fluorescent protein positive cells was significantly higher in chambers that contained 8 μg/mL of polybrene and was exposed to 20Vp-p of USWF for 5 min. In addition, the percentage increased in chambers contained 2, 4 and 8 μg/mL of polybrene when they were exposed to 25Vp-p of USWF. Comparing to those did not treated with ultrasound, the efficiency of retroviral transduction to RSCs increased 4-fold after exposed to USWF for 5 min.

CONCLUSION

We demonstrated the ability of ultrasound standing waves to improve retroviral transduction into RSCs. We believe that this may be applied to the experimental designs of future studies and may have possible therapeutic uses.