TY - JOUR A1 - Ben Ami, Tal A1 - Tong, Yuehong A1 - Bhuiyan, Alauddin A1 - Huisingh, Carrie A1 - Ablonczy, Zsolt A1 - Ach, Thomas A1 - Curcio, Christine A. A1 - Smith, R. Theodore T1 - Spatial and Spectral Characterization of Human Retinal Pigment Epithelium Fluorophore Families by Ex Vivo Hyperspectral Autofluorescence Imaging JF - Translational Vision Science & Technology N2 - Purpose: Discovery of candidate spectra for abundant fluorophore families in human retinal pigment epithelium (RPE) by ex vivo hyperspectral imaging. Methods: Hyperspectral autofluorescence emission images were captured between 420 and 720 nm (10-nm intervals), at two excitation bands (436–460, 480–510 nm), from three locations (fovea, perifovea, near-periphery) in 20 normal RPE/Bruch's membrane (BrM) flatmounts. Mathematical factorization extracted a BrM spectrum (S0) and abundant lipofuscin/melanolipofuscin (LF/ML) spectra of RPE origin (S1, S2, S3) from each tissue. Results: Smooth spectra S1 to S3, with perinuclear localization consistent with LF/ML at all three retinal locations and both excitations in 14 eyes (84 datasets), were included in the analysis. The mean peak emissions of S0, S1, and S2 at λ\(_{ex}\) 436 nm were, respectively, 495 ± 14, 535 ± 17, and 576 ± 20 nm. S3 was generally trimodal, with peaks at either 580, 620, or 650 nm (peak mode, 650 nm). At λ\(_{ex}\) 480 nm, S0, S1, and S2 were red-shifted to 526 ± 9, 553 ± 10, and 588 ± 23 nm, and S3 was again trimodal (peak mode, 620 nm). S1 often split into two spectra, S1A and S1B. S3 strongly colocalized with melanin. There were no significant differences across age, sex, or retinal location. Conclusions: There appear to be at least three families of abundant RPE fluorophores that are ubiquitous across age, retinal location, and sex in this sample of healthy eyes. Further molecular characterization by imaging mass spectrometry and localization via super-resolution microscopy should elucidate normal and abnormal RPE physiology involving fluorophores. Translational Relevance: Our results help establish hyperspectral autofluorescence imaging of the human retinal pigment epithelium as a useful tool for investigating retinal health and disease. KW - spectral characterization KW - human retinal pigment epithelium KW - fluorophores KW - hyperspectral autofluorescence imaging Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168328 VL - 5 IS - 3 ER - TY - JOUR A1 - Yousef, Yousef Al A1 - Strzalkowska, Alicja A1 - Hillenkamp, Jost A1 - Rosentreter, André A1 - Loewen, Nils A. T1 - Comparison of a second-generation trabecular bypass (iStent inject) to ab interno trabeculectomy (Trabectome) by exact matching JF - Graefe's Archive for Clinical and Experimental Ophthalmology N2 - Purpose To achieve a highly balanced comparison of trabecular bypass stenting (IS2, iStent inject) with ab interno trabeculectomy (T, Trabectome) by exact matching. Methods Fifty-three IS2 eyes were matched to 3446 T eyes. Patients were matched using exact matching by baseline intraocular pressure (IOP), the number of glaucoma medications, and glaucoma type, and using nearest neighbor matching by age. Individuals without a close match were excluded. All surgeries were combined with phacoemulsification. Results A total of 78 eyes (39 in each group) could be matched as exact pairs with a baseline IOP of 18.3 ± 5.1 mmHg and glaucoma medications of 2.7 ± 1.2 in each. IOP in IS2 was reduced to 14.6 ± 4.2 mmHg at 3 months and in T to a minimum of 13.1 ± 3.2 mmHg at 1 month. In IS2, IOP began to rise again at 6 months, eventually exceeding baseline. At 24 months, IOP in IS2 was 18.8 ± 9.0 mmHg and in T 14.2 ± 3.5 mmHg. IS2 had a higher average IOP than T at all postoperative visits (p < 0.05 at 1, 12, 18 months). Glaucoma medications decreased to 2.0 ± 1.5 in IS2 and to 1.5 ± 1.4 in T. Conclusion T resulted in a larger and sustained IOP reduction compared with IS2 where a rebound occurred after 6 months to slightly above preoperative values. KW - glaucoma surgery KW - iStent KW - trabecular bypass stent KW - trabectome KW - ab interno trabeculectomy KW - exact matching Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-232613 SN - 0721-832X VL - 258 ER - TY - JOUR A1 - Chen, Si A1 - Waxman, Susannah A1 - Wang, Chao A1 - Atta, Sarah A1 - Loewen, Ralitsa A1 - Loewen, Nils A. T1 - Dose-dependent effects of netarsudil, a Rho-kinase inhibitor, on the distal outflow tract JF - Graefe's Archive for Clinical and Experimental Ophthalmology N2 - Purpose To characterize the effects of netarsudil on the aqueous humor outflow tract distal to the trabecular meshwork (TM). Wehypothesized that netarsudil increases outflow facility in eyes with and without circumferential ab interno trabeculectomy (AIT)that removes the TM. Methods Sixty-four porcine anterior segment cultures were randomly assigned to groups with (n= 32) and without circumferential AIT (n= 32). Cultures were exposed to 0.1, 1, and 10μM netarsudil (N= 8 eyes per concentration). For each concentration,IOP and vessel diameters were compared with their respective pretreatment baselines. Outflow tract vessel diameters wereassessed by spectral-domain optical coherence tomography (SDOCT) and rendered in 4D (XYZ time series). Results Netarsudil at 1μM reduced IOP both in eyes with TM (−0.60 ± 0.24 mmHg,p= 0.01) and in eyes without TM (−1.79 ±0.42 mmHg,p< 0.01). At this concentration, vessels of the distal outflow tract dilated by 72%. However, at 0.1μMnetarsudilelevated IOP in eyes with TM (1.59 ± 0.36 mmHg,p< 0.001) as well as in eyes without TM (0.23 ± 0.32 mmHg,p<0.001). Vessels of the distal outflow tract constricted by 31%. Similarly, netarsudil at a concentration of 10μM elevated IOP both in eyeswith TM (1.91 ± 0.193,p< 0.001) and in eyes without TM (3.65 ± 0.86 mmHg,p< 0.001). At this concentration, outflow tractvessels constricted by 27%. Conclusion In the porcine anterior segment culture, the dose-dependent IOP changes caused by netarsudil matched the diameterchanges of distal outflow tract vessels. Hyper- and hypotensive properties of netarsudil persisted after TM removal KW - Rho-kinase inhibitor KW - Netarsudil KW - Distal outflow trac KW - Anterior chamber perfusion model KW - Porcine eye Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231893 SN - 0721-832X VL - 258 ER - TY - JOUR A1 - Verma-Fuehring, R. A1 - Dakroub, M. A1 - Han, H. A1 - Hillenkamp, J. A1 - Loewen, N. A. T1 - Trabeculopuncture as a predictive test of distal outflow resistance in canal-based surgery JF - Scientific Reports N2 - We investigated whether trabeculopuncture (TP) could detect distal outflow resistance to predict the outcome of canal-based glaucoma surgery such as ab interno trabeculectomy (AIT). These procedures have a high utilization in open angle glaucoma, but fail in eyes with an unidentified distal outflow resistance. We assigned 81 porcine eyes to two groups: trial (n = 42) and control (n = 39). At 24 h, four YAG-laser trabeculopunctures were placed nasally, followed by a 180° AIT at the same site at 48 h. The proportion of TP responders between both AIT groups was compared. Histology and outflow canalograms were determined. Both post-TP and post-AIT IOPs were lower than baseline IOP (p = 0.015 and p < 0.01, respectively). The success rates of TP and AIT were 69% and 85.7%, respectively. Sensitivity and specificity values of TP as predictive test for AIT success were 77.7% and 83.3%, respectively. The positive and negative predictive values were 96.6% and 38.5%, respectively. We conclude that a 10% reduction in IOP after TP can be used as a predictor for the success (> 20% IOP decrease) of 180° AIT in porcine eyes. KW - eye diseases KW - glaucoma Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299740 VL - 12 ER - TY - JOUR A1 - Lang, Stefan J. A1 - Messmer, Elisabeth M. A1 - Geerling, Gerd A1 - Mackert, Marc J. A1 - Brunner, Tobias A1 - Dollak, Sylvia A1 - Kutchoukov, Borislav A1 - Böhringer, Daniel A1 - Reinhard, Thomas A1 - Maier, Philip T1 - Prospective, randomized, double-blind trial to investigate the efficacy and safety of corneal cross-linking to halt the progression of keratoconus JF - BMC Ophthalmology N2 - Background: Corneal cross-linking is widely used to treat keratoconus. However, to date, only limited data from randomized trials support its efficacy. Methods: The efficacy and safety of corneal cross-linking for halting progression of keratoconus were investigated in a prospective, randomized, blinded, placebo controlled, multicentre trial. Twenty-nine keratoconus patients were randomized in three trial centres. The mean age at inclusion was 28 years. Longitudinal changes in corneal refraction were assessed by linear regression. The best corrected visual acuity, surface defects and corneal inflammation were also assessed. These data were analysed with a multifactorial linear regression model. Results: A total of 15 eyes were randomized to the treatment and 14 to the control group. Follow-up averaged 1098 days. Corneal refractive power decreased on average (+/-standard deviation) by 0.35 +/- 0.58 dioptres/year in the treatment group. The controls showed an increase of 0.11 +/- 0.61 dioptres/year. This difference was statistically significant (p = 0.02). Conclusions: Our data suggest that corneal cross-linking is an effective treatment for some patients to halt the progression of keratoconus. However, some of the treated patients still progressed, whereas some untreated controls improved. Therefore, further investigations are necessary to decide which patients require treatment and which do not. KW - ultraviolet-a KW - riboflavin KW - Scheimpflug KW - eyes KW - haze Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151498 VL - 15 IS - 78 ER - TY - THES A1 - Wobbe, Christina T1 - Hochaufgelöste Mikroskopie mittels strukturierter Beleuchtung zur altersabhängigen Akkumulation autofluoreszierender Granula im retinalen Pigmentepithel des Menschen T1 - High-resolution microscopy using structured illumination for age-dependent accumulation of autofluorescent granules in human retinal pigment epithelium N2 - Die Technik der strukturierten Beleuchtungsmikroskopie (structured illumination microscopy, SIM) ist eine etablierte ultrastrukturelle Aufnahmemethode, die der hochauflösenden Visualisierung intrazellulärer Strukturen dient. In der Ophthalmologie findet diese Art der Bildgebung bisher wenig Anwendung. SIM ermöglicht die histologische Darstellung retinaler Strukturen, wie der Zellen des humanen retinalen Pigmentepithels (RPE). In den Zellen des RPE reichern sich Granula an, die für die Autofluoreszenz-Bildgebung von Bedeutung sind. Anhand der Morphologie und autofluoreszierenden Merkmale lassen sich grundsätzlich drei Granulatypen im RPE unterscheiden: Melanosomen (M), Melanolipofuszin (ML)- und Lipofuszin (L)-Granula. Die Anwendung der SIM ermöglicht die präzise Darstellung und Differenzierung dieser autofluoreszierenden Strukturen, sowie die Bestimmung ihrer Anzahl und Lokalisation. Ziel der Arbeit ist die Darstellung der im humanen RPE lokalisierten Granula mithilfe der SIM. Anhand der unterschiedlichen Autofluoreszenz (AF) der Granula können diese innerhalb des RPE-Zellkörpers klassifiziert, sowie deren Anzahl und Dichte analysiert werden. Diese Analyse wird in Altersgruppen und Retinalokalisationen differenziert. Zudem sind direkte Vergleiche zwischen der Histologie (SIM, ex vivo) und klinischen Aufnahmen (Fundusautofluoreszenz, in vivo) kaum existent. Durch Ermittlung der Gesamt-AF pro Zelle in Korrelation zu der intrazellulären Granuladichte und -verteilung soll eine neue Interpretationsebene ermöglicht werden. Diese Arbeit soll helfen anhand der gewonnenen Daten die Stoffwechselmechanismen der Retina und deren Einfluss auf die Fundusautofluoreszenz (FAF) besser verstehen zu können. Sie soll insbesondere dazu beitragen bestehende und neue klinische FAF-Bildgebungsverfahren zu validieren, die Diagnostik pathologischer Prozesse der Retina zu optimieren und sowohl eine möglichst frühe Erkennung als auch präzise Prognostik zu ermöglichen. Zudem sollen die Daten eine belastbare Basis darstellen, um die mit einem hohen Zeitaufwand verbundene manuelle Zellanalyse einer geschulten künstlichen Intelligenz zu überlassen. Damit könnte der Analyseprozess von Gewebeproben immens beschleunigt werden und in seiner Effizienz maximiert werden. N2 - Structured illumination microscopy (SIM) is an established ultrastructural imaging technique for high-resolution visualization of intracellular structures. So far, this type of imaging has not been used much in ophthalmology. SIM enables the histological visualization of retinal structures, such as the cells of the hu- man retinal pigment epithelium (RPE). Granules accumulate in the cells of the RPE, which are important for autofluorescence imaging. Basically, three types of granules in the RPE can be distinguished on the basis of the morphology and autofluorescent characteristics: Melanosomes (M), Melanolipofuscin (ML) granules and Lipofuscin (L) granules. The use of SIM enables the precise representation and differentiation of these autofluorescent structures, as well as the determination of their number and localization. The aim of this work is to visualize the granules localized in human RPE using SIM. Based on the different autofluorescence (AF) of the granules, they can be classified within the RPE cell body and their number and density can be analyzed. This analysis is differentiated into age groups and retinal localizations. In addition, direct comparisons between histology (SIM, ex vivo) and clinical images (fundus autofluorescence, in vivo) hardly exist. By determining the total AF per cell in correlation to the intracellular granule density and distribution, a new level of interpretation should be made possible. This work will help to understand the metabolic mechanisms of the retina and their influence on fundus autofluorescence (FAF). In particular, it should contribute to validating existing and new clinical FAF imaging methods, optimizing the diagnosis of pathological processes in the retina and enabling both early detection and precise prognosis. In addition, the data should provide a reliable basis for leaving the time-consuming manual cell analysis to a trained artificial intelligence. This could immensely accelerate the analysis process of tissue samples and maximize its efficiency. KW - Netzhaut KW - Retinales Pigmentepithel KW - Autofluoreszenz KW - structured illumination microscopy KW - Retina Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-321490 ER - TY - JOUR A1 - Dakroub, Mohamad A1 - Verma-Fuehring, Raoul A1 - Agorastou, Vaia A1 - Schön, Julian A1 - Hillenkamp, Jost A1 - Puppe, Frank A1 - Loewen, Nils A. T1 - Inter-eye correlation analysis of 24-h IOPs and glaucoma progression JF - Graefe’s Archive for Clinical and Experimental Ophthalmology N2 - Purpose To determine whether 24-h IOP monitoring can be a predictor for glaucoma progression and to analyze the inter-eye relationship of IOP, perfusion, and progression parameters. Methods We extracted data from manually drawn IOP curves with HIOP-Reader, a software suite we developed. The relationship between measured IOPs and mean ocular perfusion pressures (MOPP) to retinal nerve fiber layer (RNFL) thickness was analyzed. We determined the ROC curves for peak IOP (T\(_{max}\)), average IOP(T\(_{avg}\)), IOP variation (IOP\(_{var}\)), and historical IOP cut-off levels to detect glaucoma progression (rate of RNFL loss). Bivariate analysis was also conducted to check for various inter-eye relationships. Results Two hundred seventeen eyes were included. The average IOP was 14.8 ± 3.5 mmHg, with a 24-h variation of 5.2 ± 2.9 mmHg. A total of 52% of eyes with RNFL progression data showed disease progression. There was no significant difference in T\(_{max}\), T\(_{avg}\), and IOP\(_{var}\) between progressors and non-progressors (all p > 0.05). Except for T\(_{avg}\) and the temporal RNFL, there was no correlation between disease progression in any quadrant and T\(_{max}\), T\(_{avg}\), and IOP\(_{var}\). Twenty-four-hour and outpatient IOP variables had poor sensitivities and specificities in detecting disease progression. The correlation of inter-eye parameters was moderate; correlation with disease progression was weak. Conclusion In line with our previous study, IOP data obtained during a single visit (outpatient or inpatient monitoring) make for a poor diagnostic tool, no matter the method deployed. Glaucoma progression and perfusion pressure in left and right eyes correlated weakly to moderately with each other. Key messages What is known: ● Our prior study showed that manually obtained 24-hour inpatient IOP measurements in right eyes are poor predictors for glaucoma progression. The inter-eye relationship of 24-hour IOP parameters and disease progression on optical coherence tomography (OCT) has not been examined. What we found: ● 24-hour IOP profiles of left eyes from the same study were a poor diagnostic tool to detect worsening glaucoma. ● Significant inter-eye correlations of various strengths were found for all tested parameters KW - glaucoma progression KW - nycthemeral intraocular pressure KW - right-left comparison KW - laterality Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323831 VL - 260 IS - 10 ER - TY - JOUR A1 - Waxman, Susannah A1 - Strzalkowska, Alicja A1 - Wang, Chao A1 - Loewen, Ralitsa A1 - Dang, Yalong A1 - Loewen, Nils A. T1 - Tissue-engineered anterior segment eye cultures demonstrate hallmarks of conventional organ culture JF - Graefe’s Archive for Clinical and Experimental Ophthalmology N2 - Background Glaucoma is a blinding disease largely caused by dysregulation of outflow through the trabecular meshwork (TM), resulting in elevated intraocular pressure (IOP). We hypothesized that transplanting TM cells into a decellularized, tissue-engineered anterior segment eye culture could restore the outflow structure and function. Methods Porcine eyes were decellularized with freeze–thaw cycles and perfusion of surfactant. We seeded control scaffolds with CrFK cells transduced with lentiviral vectors to stably express eGFP and compared them to scaffolds seeded with primary TM cells as well as to normal, unaltered eyes. We tracked the repopulation behavior, performed IOP maintenance challenges, and analyzed the histology. Results Transplanted cells localized to the TM and progressively infiltrated the extracellular matrix, reaching a distribution comparable to normal, unaltered eyes. After a perfusion rate challenge to mimic a glaucomatous pressure elevation, transplanted and normal eyes reestablished a normal intraocular pressure (transplanted = 16.5 ± 0.9 mmHg, normal = 16.9 ± 0.9). However, eyes reseeded with eGFP-expressing CrFK cells could not regulate IOP, remaining high and unstable (27.0 ± 6.2 mmHg) instead. Conclusion Tissue-engineered anterior segment scaffolds can serve as readily available, scalable ocular perfusion cultures. This could reduce dependency on scarce donor globes in outflow research and may allow engineering perfusion cultures with specific geno- and phenotypes. KW - ocular anterior segment perfusion culture KW - tissue engineering KW - aqueous humor outflow KW - trabecular meshwork Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323845 VL - 261 IS - 5 ER - TY - THES A1 - Willmann, Lukas T1 - Altersabhängige Makuladegeneration - Regeneration des retinalen Pigmentepithels durch Anregung zur Proliferation durch den Transkriptionsfaktor E2F2 T1 - Age-related macular degeneration - regeneration of retinal pigment epithelium by stimulation of proliferation by transcription factor E2F2 N2 - Altersbedingte Makuladegeneration (AMD) ist weltweit die häufigste Ursache von irreversibler Erblindung des alternden Menschen. Mit der anti-VEGF-Behandlung steht für die deutlich seltenere feuchte AMD eine zugelassene Therapie bereit, die deutlich häufigere trockene AMD entzieht sich aktuell jedoch jeglicher Therapie. Ein zentraler Pathomechanismus der AMD ist der progrediente Untergang des retinalen Pigmentepithels (RPE). Die Rarifizierung und letztendlich Atrophie des RPEs führt zum Untergang der funktionellen Einheit aus RPE, Photorezeptoren und Bruch’scher Membran und somit zum irreversiblen Funktionsverlust. Ein möglicher therapeutischer Ansatz, der progredienten Atrophie des RPEs entgegenzuwirken, ist, das prinzipiell post- mitotischen RPE zur Proliferation anzuregen. Grundlage unserer in vitro Untersuchungen ist das ARPE-19 Zellmodell. Um die Proliferation anzuregen wurden die RPE-Zellen mit E2F2, einem Zellzyklus- regulierendem Transkriptionsfaktor, transfiziert. Zunächst wurde ein nicht-proliferatives RPE-Zellmodell mit spontanem Wachstumsarrest etabliert. Innerhalb von zwei Wochen konnte die Ausbildung von Zonulae occludentes als Zeichen der Integrität des adhärenten Zellmonolayers beobachtet werden. Die chemische Transfektion von E2F2 unter einem CMV-Promoter führte zur Überexpression von E2F2-Protein. Der proliferationssteigernde Effekt von E2F2 konnte durch die Proliferationsmarker Cyclin D1 sowie Ki67, dem Anstieg der BrdU-Aufnahme und der nach Transfektion mit E2F2 zunehmenden Gesamtzellzahl nachgewiesen werden. Der Zellzahlerhöhung standen jedoch potentiell qualitative und funktionelle Einbußen entgegen. So zeigten sich nach Behandlung mit E2F2 die Zellviabilität reduziert und die Apoptoserate sowie die Permeabilität des Epithels erhöht. Diese Einschränkungen waren jedoch nur passager bis 7 Tage nach Transfektion sichtbar und reversibel. Unsere Ergebnisse weisen darauf hin, dass diese Defizite nicht durch E2F2 selbst, sondern durch das Transfektionsreagenz PEI bedingt waren. Weitere funktionelle Defizite könnten durch epithelial-mesenchymale Transition (EMT) verursacht werden. Hier zeigte sich durch E2F2 keine De-Differenzierung im Sinne einer typischen EMT-Marker- Expression. Die vorliegende Arbeit zeigt in einem in vitro Zellmodell die Grundlagen eines vielversprechenden Ansatzes zur Therapie der trockenen AMD: Durch Überexpression eines den Zellzyklus regulierenden Gens (hier E2F2) wurde die RPE-Regeneration angeregt. Analog zur schon zugelassenen Gentherapie des RPEs bei RPE65-assoziierten Netzhautdystrophien durch den Transfer von funktionstüchtigem RPE65-Gen mittels Adeno-assoziierten Viren könnte mittels E2F2, übertragen mit einem lentiviralen Verktor, eine Stimulation des RPEs zur Proliferation möglich sein. Entscheidend ist der möglichst gute Struktur- und Funktionserhalt des Photorezeptor-Bruch-Membran-RPE Komplexes. Eine Therapie sollte daher in frühen Krankheitsstadien erfolgen, um die Progression zu fortgeschrittenen Erkrankungsstadien mit irreversiblem Funktionsverlust zu verzögern oder zu verhindern. N2 - Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the ageing population worldwide. While for wet AMD an approved therapy is available in form of anti-VEGF treatment, the by far more common dry AMD is currently outside the scope of any therapy. A central pathomechanism of AMD is the progressive degeneration of the retinal pigment epithelium (RPE). Rarefication and finally atrophy of the RPE leads to the collapse of the functional unit consisting of RPE, photoreceptors and Bruch’s membrane, resulting in irreversible loss of function. A possible therapeutic strategy to prevent RPE atrophy is to stimulate the post-mitotic RPE to proliferate. The basis of our in vitro investigations is an ARPE-19 cell culture model. To stimulate proliferation, the RPE cells were transfected with E2F2, a cell cycle regulating transcription factor. First, a non-proliferative RPE cell model with spontaneous growth arrest was established. Within two weeks, the formation of zonulae occludentes was observed as a sign of the integrity of the adherent cell monolayer. Chemical transfection of E2F2 under a CMV promoter led to overexpression of E2F2 protein. The proliferation enhancing effect of E2F2 was demonstrated by proliferation markers cyclin D1 and Ki67, the increase in BrdU uptake, and the increase in total cell number after transfection with E2F2. However, the increase in cell proliferation was potentially offset by qualitative and functional losses. After treatment with E2F2, cell viability was reduced, and apoptosis rate and permeability of the epithelium were increased. These shortcomings were only temporarily detectable up to 7 days after transfection and were reversible. Our results suggest that these deficits were not caused by E2F2 itself, but by the transfection reagent PEI. Further functional deficits could be caused by epithelial-mesenchymal transition (EMT). Here, E2F2 did not show any de-differentiation in the form of typical EMT marker expression. The present study shows the basics of a promising approach for the therapy of dry AMD in an in vitro cell model: RPE regeneration was stimulated by overexpression of a gene regulating the cell cycle (here E2F2). Analogous to approved gene therapy of the RPE for RPE65-associated retinal dystrophies through transfer of functional RPE gene by adeno-associated viruses, a lentiviral vector delivering E2F2 could stimulate the RPE to proliferate. It is essential to preserve the structure and function of the photoreceptor-Bruch's membrane-RPE complex. Therapy therefore needs to take place in early stages of the disease to prevent or slow down progression to advanced stages with irreversible loss of function. KW - Netzhaut KW - Senile Makuladegeneration KW - In vitro KW - Regeneration KW - Makuladegeneration KW - E2F2 KW - transcription factor KW - RPE KW - retinal pigment epithelium KW - retina KW - Transkriptionsfaktor Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-291833 ER - TY - JOUR A1 - Guggenberger, Konstanze V. A1 - Vogt, Marius L. A1 - Song, Jae W. A1 - Weng, Andreas M. A1 - Fröhlich, Matthias A1 - Schmalzing, Marc A1 - Venhoff, Nils A1 - Hillenkamp, Jost A1 - Pham, Mirko A1 - Meckel, Stephan A1 - Bley, Thorsten A. T1 - Intraorbital findings in giant cell arteritis on black blood MRI JF - European Radiology N2 - Objective Blindness is a feared complication of giant cell arteritis (GCA). However, the spectrum of pathologic orbital imaging findings on magnetic resonance imaging (MRI) in GCA is not well understood. In this study, we assess inflammatory changes of intraorbital structures on black blood MRI (BB-MRI) in patients with GCA compared to age-matched controls. Methods In this multicenter case-control study, 106 subjects underwent BB-MRI. Fifty-six patients with clinically or histologically diagnosed GCA and 50 age-matched controls without clinical or laboratory evidence of vasculitis were included. All individuals were imaged on a 3-T MR scanner with a post-contrast compressed-sensing (CS) T1-weighted sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) BB-MRI sequence. Imaging results were correlated with available clinical symptoms. Results Eighteen of 56 GCA patients (32%) showed inflammatory changes of at least one of the intraorbital structures. The most common finding was enhancement of at least one of the optic nerve sheaths (N = 13, 72%). Vessel wall enhancement of the ophthalmic artery was unilateral in 8 and bilateral in 3 patients. Enhancement of the optic nerve was observed in one patient. There was no significant correlation between imaging features of inflammation and clinically reported orbital symptoms (p = 0.10). None of the age-matched control patients showed any inflammatory changes of intraorbital structures. Conclusions BB-MRI revealed inflammatory findings in the orbits in up to 32% of patients with GCA. Optic nerve sheath enhancement was the most common intraorbital inflammatory change on BB-MRI. MRI findings were independent of clinically reported orbital symptoms. Key Points • Up to 32% of GCA patients shows signs of inflammation of intraorbital structures on BB-MRI. • Enhancement of the optic nerve sheath is the most common intraorbital finding in GCA patients on BB-MRI. • Features of inflammation of intraorbital structures are independent of clinically reported symptoms. KW - giant cell arteritis KW - magnetic resonance imaging KW - orbit KW - ophthalmic artery KW - optic nerve Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324978 VL - 33 IS - 4 ER -