Short-term outcomes of patients with neovascular exudative AMD: the effect of COVID-19 pandemic
Graefes Arch Clin Exp Ophthalmol. 2020 Oct 3;1-8.
Enrico Borrelli, Domenico Grosso, Giovanna Vella, Riccardo Sacconi, Marco Battista, Lea Querques, Ilaria Zucchiatti, Francesco Prascina, Francesco Bandello, Giuseppe Querques
PMID: 33009973 PMCID: PMC7532341 DOI: 10.1007/s00417-020-04955-7
Purpose: To estimate the impact of delayed care during the coronavirus disease 2019 (COVID-19) pandemic on the outcomes of patients with neovascular age-related macular degeneration (AMD).
Methods: Consecutive patients with diagnosis of neovascular AMD were consecutively enrolled between March 9, 2020, and June 12, 2020, (during and immediately after the Italian COVID-19 quarantine). During the inclusion (or pandemic) visit (V0), patients received a complete ophthalmologic evaluation, including optical coherence tomography (OCT). Best-corrected visual acuity (BCVA) and OCT findings from the two preceding visits (V-1 and V-2) were compared with data at V0.
Results: One-hundred patients (112 eyes) were enrolled in this study. The time interval between following visits was 110.7 ± 37.5 days within V0 and V-1 and 80.8 ± 39.7 days within V-1 and V-2, respectively (P < 0.0001). BCVA was statistically worse at the V0 visit as compared with the immediately preceding (V-1) visit (0.50 ± 0.43 LogMAR and 0.45 ± 0.38 LogMAR at the V0 and V-1 visits, respectively; P = 0.046). On structural OCT, 91 out of 112 (81.2%) neovascular AMD eyes displayed the evidence of exudative disease activity at the V0 visit, while 77 (68.7%) eyes exhibited signs of exudation at the V-1 visit (P = 0.022). No differences in terms of BCVA and OCT findings were detected between the V-1 and V-2 visits. In multiple regression analysis, the difference in BCVA between V0 and V-1 visits was significantly associated with the interval time within these two visits (P = 0.026).
Conclusion: The COVID-19 pandemic-related postponement in patient care proved to be significantly associated with worse short-term outcomes in these patients.
Assessment of online patient education materials designed for people with age-related macular degeneration
BMC Ophthalmol. 2020 Oct 2;20(1):391.
Jennifer Fortuna, Anne Riddering, Linda Shuster, Cassie Lopez-Jeng
PMID: 33008367 PMCID: PMC7532594 DOI: 10.1186/s12886-020-01664-x
Background: Age-related macular degeneration (AMD) is a chronic eye condition that leads to permanent vision loss in the central visual field. AMD makes reading challenging and inefficient. People with AMD often find it difficult to access, process and understand written patient education materials (PEMs). To promote health literacy, the demands of written PEMs must match the literacy capacities of the target audience. This study aims to evaluate the readability (grade level) and suitability (appropriateness) of online PEMs designed for people with AMD.
Methods: Online PEMs were sourced from websites of national organizations providing patient education materials designed for people with AMD. The Flesch-Kincaid Grade Level formula and the Suitability Assessment of Materials instrument were used to assess the readability and suitability of PEMs. Descriptive statistics were used to compare online PEMs by organization based on national guidelines for readability level (≤ sixth grade) and the recommended suitability score (≥ 70%) for "superior" material.
Results: One hundred online PEMs were evaluated from websites of 16 professional organizations. The mean readability level was 9.3 (range 5.0-16.6). The mean suitability score was 53% (range 18-78%). Only six (6%) of PEMs achieved the recommended guidelines for readability level and suitability score.
Conclusion: The majority of online PEMs designed for people with AMD were written above the recommended readability level, and below the suggested suitability score. To promote health literacy, the demands of written health information must match the reading capacities of the target audience. Heeding to evidence-based guidelines for providing written information to patients with low health literacy and low vision is beneficial for both patients and health care providers. Future research is warranted.
Ten-year survival trends of neovascular age-related macular degeneration at first presentation
Br J Ophthalmol. 2020 Oct 3;bjophthalmol-2020-317161.
Cristina Arpa, Hagar Khalid, Shruti Chandra, Siegfried Wagner, Katrin Fasler, Livia Faes, Pakinee Pooprasert, Reena Chopra, Gabriella Moraes, Konstantinos Balaskas, Pearse A Keane, Sobha Sivaprasad, Dun Jack Fu
PMID: 33011683 DOI: 10.1136/bjophthalmol-2020-317161
Background: To describe 10-year trends in visual outcomes, anatomical outcomes and treatment burden of patients receiving antivascular endothelial growth factor (anti-VEGF) therapy for neovascular age-related macular degeneration (nAMD).
Methods: Retrospective cohort study of treatment-naïve, first-affected eyes with nAMD started on ranibizumab before January 1, 2009. The primary outcome was time to best-corrected visual acuity (BCVA) falling ≤35 ETDRS letters after initiating anti-VEGF therapy. Secondary outcomes included time to BCVA reaching ≥70 letters, proportion of eyes with BCVA ≥70 and ≤35 letters in 10 years, mean trend of BCVA and central retinal thickness over 10 years, and mean number of injections.
Results: For our cohort of 103 patients, Kaplan-Meier analyses demonstrated median time to BCVA reaching ≤35 and ≥70 letters were 37.8 (95% CI 22.2 to 65.1) and 8.3 (95% CI 4.8 to 20.9) months after commencing anti-VEGF therapy, respectively. At the final follow-up, BCVA was ≤35 letters and ≥70 letters in 41.1% and 21%, respectively, in first-affected eyes, while this was the case for 5.4% and 48.2%, respectively, in a patient's better-seeing eye. Mean injection number was 37.0±24.2 per eye and 53.6±30.1 at patient level (63.1% of patients required injections in both eyes).
Conclusions: The chronicity of nAMD disease and its management highlights the importance of long-term visual prognosis. Our analyses suggest that one in five patients will retain good vision (BCVA ≥70 ETDRS letters) in the first-affected eye at 10 years after starting anti-VEGF treatment; yet, one in two patients will have good vision in their better-seeing eye. Moreover, our data suggest that early treatment of nAMD is associated with better visual outcomes.
Evaluation of real-world early response of DMO to aflibercept therapy to inform future clinical trial design of novel investigational agents
Sci Rep. 2020 Oct 5;10(1):16499.
Sandra Halim, Sarega Gurudas, Shruti Chandra, John Greenwood, Sobha Sivaprasad
PMID: 33020570 PMCID: PMC7536417 DOI: 10.1038/s41598-020-73571-6
New clinical trials for diabetic macular oedema (DMO) are being designed to prove superiority over aflibercept when this agent is already very effective in improving visual acuity (VA) and DMO. The aim of this study was to determine the optimal inclusion-exclusion criteria for trials to aim for superiority in visual outcomes with newer agents. As Phase 1 studies are short duration, we aimed to evaluate the early response of aflibercept in a real-world cohort initiated on monthly aflibercept for 3 consecutive injections and observed the effects at 4 months. The sub-optimal responders were pre-defined based on different cut-offs for VA and central sub-field thickness (CST). 200 patients with treatment naïve DMO treated with 3 loading doses of aflibercept were included in the study. We found that those presenting with baseline VA of 35-54 ETDRS letters (n = 43) had higher proportion of sub-optimal responders compared to other categories (p < 0.001). Patients with baseline CST of less than 400 µm (n = 96) responded less well functionally and anatomically to loading dose than eyes with baseline CST of 400 µm or more (n = 104, p = 0.02), indicating that eyes with CST ≥ 400 µm is another inclusion criteria. There was minimal correlation between change in CST and change in VA at 4 months (r = - 0.27), suggesting that both these inclusion criteria are non-exclusive. However, for maximal efficacy, patients that meet both these inclusion criteria are more likely to show benefit from an alternative intervention. New trials should aim to include patients with treatment naïve DMO with VA between 35-54 letters and CST of 400 µm or more when aflibercept is used as the comparator.
DIAGNOSIS & IMAGING
Using Microperimetry and Low Luminance Visual Acuity to Detect the Onset of Late Age-Related Macular Degeneration: A LEAD Study Report
Retina. 2020 Sep 22.
Zhichao Wu, Chi D Luu, Lauren A B Hodgson, Emily Caruso, Fred K Chen, Usha Chakravarthy, Jennifer J Arnold, Wilson J Heriot, Jim Runciman, Robyn H Guymer, LEAD Study Group
PMID: 33009222 DOI: 10.1097/IAE.0000000000002982
Purpose: To evaluate the performance of microperimetry and low luminance visual acuity (LLVA) for detecting late age-related macular degeneration (AMD) onset.
Methods: 292 individuals with bilateral large drusen in the Laser Intervention in the Early Stages of AMD (LEAD) study underwent best-corrected visual acuity (BCVA), LLVA and microperimetry testing, as well as multimodal imaging to detect late (neovascular or atrophic) AMD onset. The performance of the change in the measurement from baseline of each of visual function test for detecting late AMD onset was compared.
Results: The area under the receiver operating characteristic curve (AUC) for detecting neovascular and atrophic AMD onset using was not significantly different for LLVA (AUC=0.71 and 0.56 respectively) and microperimetry (AUC=0.82 and 0.62 respectively) compared to BCVA (AUC=0.57 and 0.56 respectively; P≥0.126 for all). There was also only a fair degree of agreement between the three visual function measures for detecting the onset of neovascular and atrophic AMD (κ≥0.24).
Conclusions: Microperimetry, LLVA and BCVA demonstrate limited performance for detecting the earliest onset of late AMD. It remains to be established whether they perform better than current methods designed to enable self-detection of neovascular AMD onset, such as Amsler grid testing.
Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials
Prog Retin Eye Res. 2020 Oct 3;100907.
Maximilian Pfau, Jasleen Kaur Jolly, Zhichao Wu, Jonathan Denniss, Eleonora M Lad, Robyn H Guymer, Monika Fleckenstein, Frank G Holz, Steffen Schmitz-Valckenberg
PMID: 33022378 DOI: 10.1016/j.preteyeres.2020.100907
Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments.
Association between axial length and choroidal thickness in early age-related macular degeneration
PLoS One. 2020 Oct 9;15(10):e0240357.
Maho Sato, Sakiko Minami, Norihiro Nagai, Misa Suzuki, Toshihide Kurihara, Ari Shinojima, Hideki Sonobe, Kunihiko Akino, Norimitsu Ban, Kazuhiro Watanabe, Atsuro Uchida, Hajime Shinoda, Kazuo Tsubota, Yoko Ozawa
PMID: 33035241 DOI: 10.1371/journal.pone.0240357
The clinical course of age-related macular degeneration (AMD) is related to choroidal conditions, and can be determined by the evaluation of the central choroidal thickness (CCT). The aim of this study was to determine the association between the axial length (AL) and choroidal thickness in AMD by measuring these parameters in patients with and without AMD. Seventy eyes of 70 patients (34 men and 36 women; age, 64-88 years; mean age, 77.0 ± 6.5 years) who underwent cataract surgery from February 2015 to March 2020 at the Department of Ophthalmology, Keio University School of Medicine were retrospectively analyzed. The AMD group (29 patients, 29 eyes) included eyes with early AMD, whereas the control group (41 patients, 41 eyes) included those without ocular diseases other than cataract. Optical coherence tomography images were used to measure the CCT and the choroidal vessel diameter (CVD). The IOL Master was used to measure the AL. The results revealed that mean CCT was greater in the AMD group (238.3 ± 108.3 μm) compared with the age-matched control group (187.2 ± 66.8 μm) (p = 0.03). The CCT was negatively correlated with AL in the overall sample (r = -0.42, p = 0.001), the AMD group (r = -0.42, p = 0.02), and the control group (r = -0.42, p = 0.006). Note that all eyes with CCT > 350 μm were included in the AMD group. CCT and CVD were positively correlated in the overall sample (r = 0.76, p < 0.001) as well as in the individual groups (AMD: r = 0.82, p < 0.001; control: r = 0.76, p = 0.004). Given that CCT is an important parameter for predicting the prognosis of subfoveal diseases, routine evaluation of AL may be valuable for a better understanding of the pathogenesis of AMD.
Choriocapillaris Flow Deficit as a risk factor for progression of Age-Related Macular Degeneration
Retina. 2020 Sep 28.
Federico Corvi, Liran Tiosano, Giulia Corradetti, Muneeswar Gupta Nittala, Sophiana Lindenberg, Ahmed Roshdy Alagorie, John Adam McLaughlin, Thomas K Lee, Srinivas R Sadda
PMID: 33009219 DOI: 10.1097/IAE.0000000000002990
Purpose: To evaluate the association between choriocapillaris (CC) flow deficits and structural OCT biomarkers, and the progression of intermediate AMD (iAMD) to complete retinal pigment epithelial and outer retinal atrophy (cRORA).
Methods: Retrospective analysis of consecutive patients with iAMD with a minimum follow-up of 12 months. Odds ratios of intraretinal hyperreflective foci (IRHF), hyporeflective drusen cores (hDC), subretinal drusenoid deposits (SDD), presence of drusen volume (DV) ≥ 0.03 mm within a central 3-mm circle, fellow eye with late stage of AMD, CC FD at baseline and months of follow-up were estimated from logistic regression.
Results: A total of 112 eyes with iAMD were included. Eyes which progressed were significantly more likely to show IRHF, hDC and DV ≥ 0.03 mm. The CC flow deficit was also significantly greater in eyes which developed cRORA. IRHF, hDC, DV ≥ 0.03 mm and higher CC flow deficit were significantly and independently associated with the development of cRORA.
Conclusions: CC flow deficit was significantly greater in iAMD eyes that progressed to cRORA, and remained an independent risk factor when structural OCT biomarkers were considered. CC flow deficit may be useful for enhancing risk stratification and prognostication of patients with iAMD.
Developing a potential retinal OCT biomarker for local growth of geographic atrophy
Biomed Opt Express. 2020 Aug 20;11(9):5181-5196.
Yue Yu, Eric M Moult, Siyu Chen, Qiushi Ren, Philip J Rosenfeld, Nadia K Waheed, James G Fujimoto
PMID: 33014607 PMCID: PMC7510858 DOI: 10.1364/BOE.399506
Geographic atrophy (GA), the advanced stage of age-related macular degeneration, is a leading cause of blindness. GA lesions are characterized by anisotropic growth and the ability to predict growth patterns would be valuable in assessing potential therapeutics. In this study, we propose an OCT-based marker of local GA growth rate based on an axial projection of the OCT volume in the Henle fiber layer (HFL) and outer nuclear layer (ONL). We analyze the association between our proposed metric and local GA growth rates in a small longitudinal cohort of patients with AMD. These methods can potentially be used to identify risk markers, stratify patients, or assess response in future therapeutic studies.
Early Detection of Incipient Retinal Pigment Epithelium Atrophy Overlying Drusen with Fundus Autofluorescence vs. Spectral Domain Optical Coherence Tomography
J Ophthalmol. 2020 Sep 16;2020:9457457.
Anabel Rodríguez, Marc Biarnés, Rosa M Coco-Martin, Anna Sala-Puigdollers, Jordi Monés
PMID: 33014447 PMCID: PMC7519191 DOI: 10.1155/2020/9457457
Purpose: This study aims to find out which tool, fundus autofluorescence (FAF) or spectral domain optical coherence tomography (SD-OCT), is more sensitive in detecting retinal pigment epithelium (RPE) demise overlying drusen and can, therefore, help predict geographic atrophy (GA) appearance in Age-Related Macular Degeneration (AMD).
Methods: A single-site, retrospective, observational, longitudinal study was conducted. Patients with intermediate AMD (iAMD) (large (>125 μm) or intermediate (63-125 μm) drusen with hyper/hypopigmentation) with a minimum follow-up of 18 months were included. Drusen with overlying incipient RPE atrophy were identified on SD-OCT defined as choroidal hypertransmission or nascent geographic atrophy (nGA). These selected drusen were, then, traced backwards in time to determine if incipient RPE atrophy overlying drusen was observed on FAF (well-demarcated region of absence of autofluorescence) before, simultaneously, or after having detected the first signs of incipient RPE atrophy on SD-OCT. The number of drusen in which signs of incipient RPE atrophy was detected earlier using FAF or SD-OCT was compared. The time elapsed from the identification with the more sensitive method to the other was recorded and analyzed.
Results: One hundred and thirty-three drusen in 22 eyes of 22 patients were included. Of these, 112 (84.2%) drusen showed choroidal hypertransmission and 21(15.8%) nGA. Early signs of atrophy overlying drusen were found simultaneously on SD-OCT and FAF in 52 cases (39.1%, 95% CI 30.8-47.9%), earliest on FAF in 51 (38.3%, 95% CI 30.0-47.2%) and first on SD-OCT in 30 (22.6%, 95% CI 15.8-30.6%; p < 0.05). Statistically significant differences were found between both techniques (p=0.005), with FAF detecting it earlier than SD-OCT. When RPE atrophy was found first on FAF, the median time to diagnosis with SD-OCT was 6.6 months (95% CI 5.5 to 8.6), while if detection occurred earlier on SD-OCT, the median time until identification with FAF was 12.6 months (95% CI 6.0 to 23.4; p=0.0003).
Conclusions: In iAMD cases in which early atrophy overlying drusen is not detected simultaneously in FAF and SD-OCT, FAF was significantly more sensitive. Nevertheless, a multimodal approach is recommended and required to evaluate these patients.
Quantitative analysis of inner retinal structural and microvascular alterations in intermediate age-related macular degeneration: a swept-source OCT angiography study
Photodiagnosis Photodyn Ther. 2020 Oct 1;102030.
Sehnaz Ozcaliskan, Ozgur Artunay, Sevcan Balci, Irfan Perente, Nursal Melda Yenerel
PMID: 33011396 DOI: 10.1016/j.pdpdt.2020.102030
Purpose: To investigate the structural and microvascular alterations of the inner retinal layers in patients with intermediate age-related macular degeneration (iAMD), and determine an association between structural and microvascular parameters
Methods: In this prospective study, 58 eyes of iAMD patients and 64 age and sex-matched control eyes were enrolled. Participants underwent spectral-domain optical coherence tomography (OCT) and swept-source OCT angiography (OCTA) imaging. Retinal layer segmentation was performed automatically using the built-in software of the OCT device. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer plexiform layer (OPL) thicknesses were analyzed in the central and parafoveal region. Foveal avascular zone (FAZ) area and vessel density of the superficial and deep capillary plexuses (SCP and DCP) in the fovea and parafoveal region were obtained.
Results: In iAMD eyes, the RNFL, GCL, and IPL were significantly thinner compared to control eyes in the parafovea (p < 0.05 all). The overall parafoveal SCP vessel density significantly decreased in iAMD eyes compared to the controls (p = 0.022). There was also a non-significant reduction in DCP vessel density measurements in iAMD eyes compared to controls (p > 0.05 all). The ganglion cell complex was significantly correlated with SCP vessel density measurements in iAMD eyes (r = 0.224, p = 0.043).
Conclusion: This study demonstrates that inner retina is also affected in iAMD in terms of structural and microvascular components. Inner retinal thinning is significantly correlated with vessel density reduction, suggesting a cause and effect relationship between these parameters. Further longitudinal studies may aid in characterizing these alterations and better understanding the AMD pathogenesis.
IL-1/IL-1R signaling induced by all-trans-retinal contributes to complement alternative pathway activation in retinal pigment epithelium
J Cell Physiol. 2020 Oct 9.
Xinxuan Cheng, Danxue He, Chunyan Liao, Sijie Lin, Liying Tang, Yuan-Liang Wang, Jiaoyue Hu, Wei Li, Zuguo Liu, Yalin Wu, Yi Liao
PMID: 33034385 DOI: 10.1002/jcp.30103
The underlying mechanisms of complement activation in Stargardt disease type 1 (STGD1) and age-related macular degeneration (AMD) are not fully understood. Overaccumulation of all-trans-retinal (atRAL) has been proposed as the pathogenic factor in both diseases. By incubating retinal pigment epithelium (RPE) cells with atRAL, we showed that C5b-9 membrane attack complexes (MACs) were generated mainly through complement alternative pathway. An increase in complement factor B (CFB) expression as well as downregulation of complement regulatory proteins CD46, CD55, CD59, and CFH were observed in RPE cells after atRAL treatment. Furthermore, interleukin-1β production was provoked in both atRAL-treated RPE cells and microglia/macrophages. Coincubation of RPE cells with interleukin-1 receptor antagonist (IL1Ra) and atRAL ameliorated complement activation and downregulated CFB expression by attenuating both p38 and c-Jun N-terminal kinase (JNK) signaling pathways. Our findings demonstrate that atRAL induces an autocrine/paracrine IL-1/IL-1R signaling to promote complement alternative pathway activation in RPE cells and provide a novel perspective on the pathomechanism of macular degeneration.
Genetic rescue of X-linked retinoschisis mouse (Rs1-/y) retina induces quiescence of the retinal microglial inflammatory state following AAV8-RS1 gene transfer and identifies gene networks underlying retinal recovery
Hum Gene Ther. 2020 Oct 6.
Camasamudram Vijayasarathy, Yong Zeng, Matthew Brooks, Robert N Fariss, Paul A Sieving
PMID: 33019822 DOI: 10.1089/hum.2020.213
To understand RS1 gene interaction networks in the X-linked retinoschisis (XLRS) mouse retina (Rs1-/y), we analyzed the transcriptome by RNA-seq before and after in vivo expression of exogenous retinoschisin (RS1) gene delivered by AAV8. RS1 is a secreted cell adhesion protein that is critical for maintaining structural lamination and synaptic integrity of the neural retina. RS1 loss-of-function mutations cause XLRS disease in young boys and men, with splitting ("schisis") of retinal layers and synaptic dysfunction that causes progressive vision loss with age. Analysis of differential gene expression profiles and pathway enrichment analysis of Rs1-KO (Rs1-/y) retina identified cell surface receptor signaling and positive regulation of cell adhesion as potential RS1 gene interaction networks. Most importantly, it also showed massive dysregulation of immune response genes at early age, with characteristics of a microglia-driven pro-inflammatory state. Delivery of AAV8-RS1 primed the Rs1-KO retina towards structural and functional recovery. The disease transcriptome transitioned towards a recovery phase with upregulation of genes implicated in wound healing, anatomical structure (camera type eye) development, metabolic pathways, and collagen IV networks that provide mechanical stability to basement membrane. AAV8-RS1 expression also attenuated the microglia gene signatures to low levels toward immune quiescence. This study is among the first to identify RS1 gene interaction networks that underlie retinal structural and functional recovery after RS1 gene therapy. Significantly, it also shows that providing wild-type RS1 gene function caused the retina immune status to transition from a degenerative inflammatory phenotype toward immune quiescence, even though the transgene is not directly linked to microglia function. This study indicates that inhibition of microglial pro-inflammatory responses are an integral part of therapeutic rescue in XLRS gene therapy, and gene therapy might realize its full potential if delivered before microglia activation and photoreceptor cell death.
Targeted Knockout of the Vegfa Gene in the Retina by Subretinal Injection of RNP Complexes Containing Cas9 Protein and Modified sgRNAs
Mol Ther. 2020 Sep 23;S1525-0016(20)30489-5.
Andreas Braae Holmgaard, Anne Louise Askou, Emilie Grarup Jensen, Sidsel Alsing, Rasmus O Bak, Jacob Giehm Mikkelsen, Thomas J Corydon
PMID: 33022212 DOI: 10.1016/j.ymthe.2020.09.032
The therapeutic effect of retinal gene therapy using CRISPR/Cas9-mediated genome editing and knockout applications is dependent on efficient and safe delivery of gene-modifying tool kits. Recently, transient administration of single guide RNAs (sgRNAs) and SpCas9 proteins delivered as ribonucleoproteins (RNPs) has provided potent gene knockout in vitro. To improve efficacy of CRISPR-based gene therapy, we delivered RNPs containing SpCas9 protein complexed to chemically modified sgRNAs (msgRNAs). In K562 cells, msgRNAs significantly increased the insertion/deletion (indel) frequency (25%) compared with unmodified counterparts leading to robust knockout of the VEGFA gene encoding vascular endothelial growth factor A (96% indels). Likewise, in HEK293 cells, lipoplexes containing varying amounts of RNP and EGFP mRNA showed efficient VEGFA knockout (43% indels) and strong EGFP expression, indicative of efficacious functional knockout using small amounts of RNP. In mice, subretinal injections of equivalent lipoplexes yielded 6% indels in Vegfa of isolated EGFP-positive RPE cells. However, signs of toxicity following delivery of lipoplexes containing high amounts of RNP were observed. Although the mechanism resulting in the varying efficacy remains to be elucidated, our data suggest that a single subretinal injection of RNPs carrying msgRNAs and SpCas9 induces targeted retinal indel formation, thus providing a clinically relevant strategy relying on nonviral delivery of short-lived nuclease activity.
Transplantation Efficacy of Human Ciliary Epithelium Cells from Fetal Eye and Lin-ve Stem Cells from Umbilical Cord Blood in the Murine Retinal Degeneration Model of Laser Injury
Cell Transplant. Jan-Dec 2020;29:963689720946031.
Sridhar Bammidi, Parul Bali, Jaswinder Kalra, Akshay Anand
PMID: 33023312 DOI: 10.1177/0963689720946031
A number of degenerative conditions affecting the neural retina including age-related macular degeneration have no successful treatment, resulting in partial or complete vision loss. There are a number of stem cell replacement strategies for recovery of retinal damage using cells from variable sources. However, literature is still deficit in the comparison of efficacy of types of stem cells. The purpose of the study was to compare the therapeutic efficacy of undifferentiated cells, i.e., lineage negative stem cells (Lin-ve SC) with differentiated neurosphere derived from ciliary epithelium (CE) cells on retinal markers associated with laser-induced retinal injury. Laser-induced photocoagulation was carried out to disrupt Bruch's membrane and retinal pigmented epithelium in C57BL/6 mouse model. Lineage negative cells were isolated from human umbilical cord blood, whereas neurospheres were derived from CE of post-aborted human eyeballs. The cells were then transplanted into subretinal space to study their effect on injury. Markers of neurotropic factors, retina, apoptosis, and proliferation were analyzed after injury and transplantation. mRNA expression was also analyzed by real-time polymerase chain reaction at 1 week, and 3-month immunohistochemistry was evaluated at 1-week time point. CE cell transplantation showed enhanced differentiation of rods and retinal glial cells. However, Lin-ve cells exerted paracrine-dependent modulation of neurotrophic factors, which is possibly mediated by antiapoptotic and proliferative effects. In conclusion, CE transplantation showed superior regenerative outcome in comparison to Lin-ve SC for rescue of artificially injured rodent retinal cells. It is imperative that this source for transplantation may be extensively studied in various doses and additional retinal degeneration models for prospective clinical applications.
Incomplete response to Anti-VEGF therapy in neovascular AMD: Exploring disease mechanisms and therapeutic opportunities
Prog Retin Eye Res. 2020 Oct 3;100906.
Priyatham S Mettu, Michael J Allingham, Scott W Cousins
PMID: 33022379 DOI: 10.1016/j.preteyeres.2020.100906
Intravitreal anti-vascular endothelial growth factor (VEGF) drugs have revolutionized the treatment of neovascular age-related macular degeneration (NVAMD). However, many patients suffer from incomplete response to anti-VEGF therapy (IRT), which is defined as (1) persistent (plasma) fluid exudation; (2) unresolved or new hemorrhage; (3) progressive lesion fibrosis; and/or (4) suboptimal vision recovery. The first three of these collectively comprise the problem of persistent disease activity (PDA) in spite of anti-VEGF therapy. Meanwhile, the problem of suboptimal vision recovery (SVR) is defined as a failure to achieve excellent functional visual acuity of 20/40 or better in spite of sufficient anti-VEGF treatment. Thus, incomplete response to anti-VEGF therapy, and specifically PDA and SVR, represent significant clinical unmet needs. In this review, we will explore PDA and SVR in NVAMD, characterizing the clinical manifestations and exploring the pathobiology of each. We will demonstrate that PDA occurs most frequently in NVAMD patients who develop high-flow CNV lesions with arteriolarization, in contrast to patients with capillary CNV who are highly responsive to anti-VEGF therapy. We will review investigations of experimental CNV and demonstrate that both types of CNV can be modeled in mice. We will present and consider a provocative hypothesis: formation of arteriolar CNV occurs via a distinct pathobiology, termed neovascular remodeling (NVR), wherein blood-derived macrophages infiltrate the incipient CNV lesion, recruit bone marrow-derived mesenchymal precursor cells (MPCs) from the circulation, and activate MPCs to become vascular smooth muscle cells (VSMCs) and myofibroblasts, driving the development of high-flow CNV with arteriolarization and perivascular fibrosis. In considering SVR, we will discuss the concept that limited or poor vision in spite of anti-VEGF may not be caused simply by photoreceptor degeneration but instead may be associated with photoreceptor synaptic dysfunction in the neurosensory retina overlying CNV, triggered by infiltrating blood-derived macrophages and mediated by Müller cell activation Finally, for each of PDA and SVR, we will discuss current approaches to disease management and treatment and consider novel avenues for potential future therapies.
Retinal Degeneration and Alzheimer's Disease: An Evolving Link
Int J Mol Sci. 2020 Oct 2;21(19):E7290.
Ajay Ashok, Neena Singh, Suman Chaudhary, Vindhya Bellamkonda, Alexander E Kritikos, Aaron S Wise, Neil Rana, Dallas McDonald, Rithvik Ayyagari
PMID: 33023198 DOI: 10.3390/ijms21197290
Age-related macular degeneration (AMD) and glaucoma are degenerative conditions of the retina and a significant cause of irreversible blindness in developed countries. Alzheimer's disease (AD), the most common dementia of the elderly, is often associated with AMD and glaucoma. The cardinal features of AD include extracellular accumulation of amyloid β (Aβ) and intracellular deposits of hyper-phosphorylated tau (p-tau). Neuroinflammation and brain iron dyshomeostasis accompany Aβ and p-tau deposits and, together, lead to progressive neuronal death and dementia. The accumulation of Aβ and iron in drusen, the hallmark of AMD, and Aβ and p-tau in retinal ganglion cells (RGC), the main retinal cell type implicated in glaucoma, and accompanying inflammation suggest overlapping pathology. Visual abnormalities are prominent in AD and are believed to develop before cognitive decline. Some are caused by degeneration of the visual cortex, while others are due to RGC loss or AMD-associated retinal degeneration. Here, we review recent information on Aβ, p-tau, chronic inflammation, and iron dyshomeostasis as common pathogenic mechanisms linking the three degenerative conditions, and iron chelation as a common therapeutic option for these disorders. Additionally discussed is the role of prion protein, infamous for prion disorders, in Aβ-mediated toxicity and, paradoxically, in neuroprotection.
Curr Opin Ophthalmol. 2020 Nov;31(6):563-571.
Mahmood J Khan, Thanos Papakostas, Kyle Kovacs, Mrinali P Gupta
PMID: 33002988 DOI: 10.1097/ICU.0000000000000714
Purpose of review: The purpose of this article is to provide an overview of drug-induced maculopathies including their clinical presentations, diagnostic findings, and treatment options. With the increasing pace of development and arrival of drugs to the market, this review aims to inform retina specialists of relevant side effects that may be encountered in a clinical practice setting.
Recent findings: The major themes visited in this article focus on relevant findings of drugs that cause pigmentary and crystalline maculopathy, photoreceptor dysfunction, cystoid macular edema, central serous choroidopathy, uveitis, and vascular damage.
Summary: The current review reports updated findings and discusses the pathophysiologic mechanisms, presentations, and treatments of drug-induced maculopathies.
Meticulous multimodal analysis of aflibercept therapy for submacular vascularized pigment epithelial detachment associated with neovascular AMD in a prospective case series, the EVEN study
Am J Ophthalmol Case Rep. 2020 Sep 18;20:100916.
Clement K Chan, David Sarraf, Prema Abraham, Maziar Lalezary, Steven G Lin, Xuejing Chen, Muneeswar Gupta Nittala, SriniVas Sadda
PMID: 33024885 PMCID: PMC7527713 DOI: 10.1016/j.ajoc.2020.100916
Purpose: This prospective case series investigates the visual and anatomical outcomes including detailed volumetrics of eyes with vascularized pigment epithelial detachments (PED) treated with aflibercept in eyes with neovascular age-related macular degeneration (nAMD) through meticulous analysis in a reading center setting.
Methods: We conducted a single-arm multicenter, prospective, open-labeled, interventional case series, comparing visual and anatomic outcomes at 12 months with baseline for intense aflibercept therapy. Eyes with submacular vascularized PED due to AMD received 2.0 mG of intravitreal aflibercept at baseline and then monthly for 6 months. During the subsequent 6 months, mandatory aflibercept therapy was given for every other month, while additional aflibercept injections were allowed between mandatory injections if necessary, at 4 weeks after last injection, contingent on pre-defined visual and anatomic re-treatment criteria. Standardized ETDRS vision measurement, anterior and posterior segment examination, and high-density spectral-domain optical coherence tomography scans were obtained at baseline and monthly, while fundus photography and fluorescein angiography were obtained at baseline, 3,6, and 12 months. Indocyanine-green angiography was obtained at baseline and 3 months. Meticulous multidimensional assessment of the scanned multimodal serial images was then performed by Doheny Image Reading Center.
Results: Of 36 eyes and patients with mean age of 80, mean baseline and 12-month-ETDRS BCVA was 59 ± 8.9 letters (20/66), and 65 ± 27 letters (20/50), respectively; (6.5 letters improvement, p = 0.02). Significant reductions from baseline to month-12 were noted for multiple anatomic measures, including PED maximum height, entire lesion and central 1-mm subfield of PED mean thickness and volume, and mean subretinal hyperreflective material (SHRM) thickness and volume, also entire lesion of retinal thickness, retinal volume, and mean subretinal fluid (SRF) thickness (mean reductions in magnitude ranging from 37.5 to 91.7%, all p < 0.001). FA measurements also showed significant decrease from baseline to month-12, including area and greatest linear diameter (GLD) of fibrovascular PED, area and GLD of NV area and leakage (mean reductions in magnitude from 41.9 to 87.7%, p value from 0.002 to <0.001). This case series shows that while majority of reductions in SRF volume occurred during first month from baseline, majority of reduction in retinal, PED, and SHRM volumes occurred during first 2 months after onset of anti-VEGF injections. RPE tears developed in 5 eyes (13.9%) correlating with eyes with large PED height and volume at baseline (mean height >800 μm, mean volume >4 mm3). Geographic atrophy (GA) was noted in only 1 eye at baseline, but in 16 eyes (44.4%) by 12 months.
Conclusions and importance: Significant improvement in vision and anatomic measures including volumetrics of vPED were noted at 12 months after aflibercept therapy. Besides substantial PED height, large PED volume at baseline also correlated with RPE tears in 13.9% of eyes with vPED after anti-VEGF therapy. Reduction in SHRM correlated directly with decrease in PED, and more than 40% of study eyes developed GA by 12 months following intense anti-VEGF therapy.