Deficiency in Retinal TGFß Signaling Aggravates Neurodegeneration by Modulating Pro-Apoptotic and MAP Kinase Pathways.

Transforming growth factor ß (TGFß) signaling has manifold functions such as regulation of cell growth, differentiation, migration, and apoptosis. Moreover, there is increasing evidence that it also acts in a neuroprotective manner. We recently showed that TGFß receptor type 2 (Tgfbr2) is upregulated in retinal neurons and Müller cells during retinal degeneration. In this study we investigated if this upregulation of TGFß signaling would have functional consequences in protecting retinal neurons. To this end, we analyzed the impact of TGFß signaling on photoreceptor viability using mice with cell type-specific deletion of Tgfbr2 in retinal neurons and Müller cells (Tgfbr2ΔOC) in combination with a genetic model of photoreceptor degeneration (VPP). We examined retinal morphology and the degree of photoreceptor degeneration, as well as alterations of the retinal transcriptome. In summary, retinal morphology was not altered due to TGFß signaling deficiency. In contrast, VPP-induced photoreceptor degeneration was drastically exacerbated in double mutant mice (Tgfbr2ΔOC; VPP) by induction of pro-apoptotic genes and dysregulation of the MAP kinase pathway. Therefore, TGFß signaling in retinal neurons and Müller cells exhibits a neuroprotective effect and might pose promising therapeutic options to attenuate photoreceptor degeneration in humans.

[Analysis of adverse drug reactions (ADR) in fluorescein angiography (FAG) and indocyanine green angiography (ICGA) and indications before and during the COVID-19 pandemic at a university eye hospital]. / Analyse von unerwünschten Arzneimittelwirkungen (UAW) bei Fluoreszeinangiographie (FAG) und Indocyaningrünangiographie (ICGA) und der Indikationsstellung vor und während der COVID-19-Pandemie an einer Universitätsaugenklinik.

BACKGROUND: This study was an analysis of fluorescein angiography (FAG) and indocyanine green angiography (ICGA) at a university eye hospital. The primary objective of the study was to analyze adverse drug reactions (ADRs) and their severity (mild, moderate, severe). The secondary objective was to investigate the indications of FAG and ICGA before and during the COVID-19 pandemic. METHODS: A retrospective analysis of all FAG and ICGA at the University Eye Hospital in Würzburg from January 2016 to the end of December 2021 was performed. The ADRs, gender, age, examination time points and indications were evaluated. The ADRs were classified into mild, moderate, and severe, following the definition of Kornblau et al. [1] RESULTS: A total of 4900 examinations from 4193 patients were analyzed. An FAG was performed slightly more frequently in men (54.8%) than in women (45.2%) and the mean age was 63.2 ± 16.9 years (median: 65 years). The ADRs occurred in only 1.65% of all FAG, of which 1.27% were mild and 0.39% were moderate. No severe ADRs occurred. The most common ADR was nausea at 59.26%. No ADR occurred in ICGA. The annual number of FAGs averaged 816.7 ± 91.1 and was relatively constant throughout the period except for a significantly reduced number in 2016 (compared with 2018, 2019, and 2021). The most common indication for FAG was venous retinal occlusion at 22.93% (N = 774), showing a significant increase in 2021 compared to 2018-2020. An ICGA was performed in 4.18% of cases, with the most common indication being uveitis at 31.82% (N = 63). CONCLUSION: Compared to other studies very few ADRs occurred and no life-threatening ADR occurred in any case. Venous retinal occlusions were very common indications for FAG, probably due to the frequent need for repeated examinations in this condition. Briefly, during the first lockdown (18 March-8 May 2020), a decrease in angiographies was observed, but over a longer period, no significant differences were seen compared with the prepandemic period.

Quantitative Fundus Autofluorescence in Systemic Chloroquine/Hydroxychloroquine Therapy: One Year Follow-Up.

Purpose: Systemic chloroquine/hydroxychloroquine (CQ/HCQ) can cause severe ocular side effects including bull's eye maculopathy (BEM). Recently, we reported higher quantitative autofluorescence (QAF) levels in patients with CQ/HCQ intake. Here, QAF in patients taking CQ/HCQ in a 1-year follow-up is reported. Methods: Fifty-eight patients currently or previously treated with CQ/HCQ (cumulative doses 94-2435 g) and 32 age- and sex-matched healthy subjects underwent multimodal retinal imaging (infrared, red free, fundus autofluorescence [FAF], QAF [488 nm], and spectral-domain optical coherence tomography (SD-OCT). For analysis, custom written FIJI plugins were used for image processing, multimodal image stacks assembling, and QAF calculation. Results: Thirty patients (28 without BEM and 2 with BEM, age range = 25-69 years) were followed up (370 ± 63 days). QAF values in patients taking CQ/HCQ showed a significant increase between baseline and follow-up examination: 282.0 ± 67.9 to 297.7 ± 70.0 (QAF a.u.), P = 0.002. An increase up to 10% was observed in the superior macular hemisphere. Eight individuals (including 1 patient with BEM) had a pronounced QAF increase of up to 25%. Compared to healthy controls, QAF levels in patients taking CQ/HCQ were significantly increased (P = 0.04). Conclusions: Our study confirms our previous finding of increased QAF in patients taking CQ/HCQ with a further significant QAF increase from baseline to follow-up. Whether pronounced QAF increase might predispose for rapid progression toward structural changes and BEM development is currently investigated in ongoing studies. Translational Relevance: In addition to standard screening tools during systemic CQ/HCQ treatment, QAF imaging might be useful in CQ/HCQ monitoring and could serve as a screening tool in the future.

Quantitative Fundus Autofluorescence in the Developing and Maturing Healthy Eye.

Purpose: Quantitative fundus autofluorescence (QAF) enables comparisons of autofluorescence intensities among participants. While clinical QAF reports mostly focused on the healthy and diseased adult retina, only very limited data of QAF in the maturing eye are available. Here, we report QAF in a large cohort of healthy children. Methods: In this prospective monocentric cross-sectional study, 70 healthy Caucasian children (5-18 years) were multimodal imaged, including QAF and spectral domain optical coherence tomography. QAF and retinal thicknesses were measured at predefined locations (along horizontal meridian; Early Treatment Diabetic Retinopathy Study [ETDRS] grid) and correlated using custom written Fiji plugins. Standard retinae for different age groups were generated. Results: Fifty-three participants were included. QAF was low in childhood but increased steadily (P < 0.001), also at the fovea (P < 0.001), with no gender differences (P = 0.61). The QAF distribution was similar to adults showing highest values superior-temporally. At individual points, retinal thickness remained stable, while using the ETDRS pattern, the retinal pigment epithelium (RPE) thickness increased significantly with aging. Standard QAF retinae of age groups also showed an increase with aging. Conclusions: QAF can be reliably performed in young children. Function-structure correlation showed a thickening of the RPE and an increasing QAF with aging, probably related to the histologic low number of RPE autofluorescent granules at a younger age but further deposition of these granules during maturation. Standard retinae help to distinguish abnormal QAF in the diseased retina of age-matched patients. Translational Relevance: Our data bridge the gap between preclinical QAF and clinical data application and structural OCT correlation in children.

Quantitative Fundus Autofluorescence: Advanced Analysis Tools.

Purpose: To use multimodal retinal images (including quantitative fundus autofluorescence [QAF]) for spectral-domain optical coherence tomography (SD-OCT)-based image registration and alignment. For each age decade of healthy adults, normative fine-grained QAF retinal maps are generated and advanced methods for QAF image analysis are applied. Methods: Multimodal retinal images were obtained from 103 healthy subjects (age 19-77 years; unremarkable retina/macula, age-appropriate clear optic media). Custom written FIJI plugins enabled: (1) determination of the fovea in SD-OCT and the edge of the optic disc in infrared (IR) images; (2) alignment and superimposition of multimodal retinal images based on foveal and optic disc position; (3) plotting of normative QAF retinal maps for each decade; and (4) comparison of individual retinas with normative retinas of different decades using newly introduced analysis patterns (QAF97, freehand tool). Results: SD-OCT based image registration enables easy image registration, alignment, and analysis of different modalities (QAF, IR, and SD-OCT here reported). In QAF, intensities significantly increase with age with two major inclines between the third/fourth and seventh/eighth decades. With aging, the parafoveal area of maximum QAF intensity slightly shifts from temporal-superior to temporal. Compared with standard QAF analysis, refined QAF analysis patterns reveal a more detailed analysis of QAF, especially in the diseased retina. Conclusions: Age-related QAF normative retinal maps can be used to directly compare and classify individual's QAF intensities. Advanced QAF analysis tools will further help to interpret autofluorescence changes in normal aging and in the diseased retina in a multimodal imaging setting. Translational Relevance: Advanced methods for QAF analysis link basic findings with clinical observations in normal aging and in the diseased macula.

Quantitative Fundus Autofluorescence in Systemic Chloroquine/Hydroxychloroquine Therapy.

Purpose: To investigate the effect of systemic chloroquine/hydroxychloroquine (CQ/HCQ) on outer retinal health using quantitative fundus autofluorescence (QAF) imaging. Methods: For this prospective, cross-sectional study, 44 CQ/HCQ patients and 25 age-matched controls underwent multimodal retinal imaging including QAF (488 nm) and spectral-domain optical coherence tomography (SD-OCT) in addition to the recommended CQ/HCQ screening procedures. Custom written FIJI plugins enabled detailed QAF analysis and correlation with retinal thickness and comparison to the healthy controls. Results: Out of 44 patients, 29 (mean age 43.5 ± 12.2, range 22-59 years) exposed to CQ/HCQ (mean cumulative dose 724.2 ± 610.4 g, median 608.0 g, range 18.6-2171.0 g) met eligibility criteria. Four of these 29 patients had bull's-eye maculopathy (BEM). Mean QAF values were significantly higher in CQ/HCQ patients than in healthy controls. QAF increase started early after treatment onset, remained high even years after treatment cessation, and was not accompanied by pathologies in the other screening methods, including retinal thicknesses (except in BEM patients). Conclusions: QAF might be a useful tool in retinal imaging and in verifying systemic CQ/HCQ intake. The early onset and preserved high levels of QAF parallel findings of CQ deposition in the retina in animal models. Whether QAF can be used as a screening tool to detect early CQ/HCQ related maculopathy is the subject of long-term ongoing studies. Translation Relevance: Experimental QAF imaging in systemic CQ/HCQ therapy monitoring might be a useful tool to indicate the drug or its metabolites and to detect metabolic retinal changes.