Philipp Herrmann

Semiautomated Image Processing Method for Identification and Quantification of Geographic Atrophy in Age-Related Macular Degeneration

PURPOSE To determine intraobserver and interobserver longitudinal measurement variability of novel semiautomated software for quantification of age-related macular degeneration-associated geographic atrophy (GA) based on confocal scanning laser ophthalmoscopy fundus autofluorescence (FAF) imaging. METHODS Three-field FAF (excitation 488 nm, emission 500-700 nm), near-infrared reflectance (820 nm), and blue reflectance (488 nm) images of 30 GA subjects were recorded according to a standardized protocol at baseline after 6 and 12 months. At all visits, the GA area was analyzed on central FAF images by seven independent readers using semiautomated software. The software allows direct export of FAF images from the database and semiautomated detection of atrophic areas by shadow correction, vessel detection, and selection of seed points. RESULTS The mean size of atrophy at baseline and the mean progression rate were 5.96 mm² (range, 1.80-15.87) and 1.25 mm²/year (0.42-2.93), respectively. Mean difference of interobserver agreement (Bland-Altman statistics) ranged from -0.25 to 0.30 mm² for the baseline visit and from -0.14 to 0.11 mm²/year for the atrophy progression rate. Corresponding reflectance images were helpful for lesion boundary discrimination, particularly for evaluation of foveal GA involvement and when image quality was poor. CONCLUSIONS The new image processing software offers an accurate, reproducible, and time-efficient identification and quantification of outer retinal atrophy and its progression over time. It facilitates measurements both in natural history studies and in interventional trials to evaluate new pharmacologic agents designed to limit GA enlargement.

Rescue of the Stargardt phenotype in Abca4 knockout mice through inhibition of vitamin A dimerization

Significance Accumulation of lipofuscin in the retinal pigment epithelium precedes retinal degenerations and dystrophies responsible for blindness-causing retinal diseases. The mechanism behind lipofuscin formation in the retina or in any tissue is poorly understood. Here we show in mice that the dimerization of vitamin A is responsible for triggering the formation of more than 50% of ocular lipofuscin. Replacing three hydrogen atoms on vitamin A with deuterium inhibits vitamin A dimerization, resulting in reduced lipofuscin and transcriptional normalization of genes associated with inflammation without compromising retinal function. Thus, vitamin A deuterated at the carbon 20 position provides a clinically amiable tool to prevent vitamin A dimerization in humans to assess whether impeding such dimerization might prevent retinal degenerations such as Stargardt disease and age-related macular degeneration. Stargardt disease, an ATP-binding cassette, subfamily A, member 4 (ABCA4)-related retinopathy, is a genetic condition characterized by the accelerated accumulation of lipofuscin in the retinal pigment epithelium, degeneration of the neuroretina, and loss of vision. No approved treatment exists. Here, using a murine model of Stargardt disease, we show that the propensity of vitamin A to dimerize is responsible for triggering the formation of the majority of lipofuscin and transcriptional dysregulation of genes associated with inflammation. Data further demonstrate that replacing vitamin A with vitamin A deuterated at the carbon 20 position (C20-D3-vitamin A) impedes the dimerization rate of vitamin A—by approximately fivefold for the vitamin A dimer A2E—and subsequent lipofuscinogenesis and normalizes the aberrant transcription of complement genes without impairing retinal function. Phenotypic rescue by C20-D3-vitamin A was also observed noninvasively by quantitative autofluorescence, an imaging technique used clinically, in as little as 3 months after the initiation of treatment, whereas upon interruption of treatment, the age-related increase in autofluorescence resumed. Data suggest that C20-D3-vitamin A is a clinically amiable tool to inhibit vitamin A dimerization, which can be used to determine whether slowing the dimerization of vitamin A can prevent vision loss caused by Stargardt disease and other retinopathies associated with the accumulation of lipofuscin in the retina.

Assessment and In Vivo Scoring of Murine Experimental Autoimmune Uveoretinitis Using Optical Coherence Tomography

Despite advances in clinical imaging and grading our understanding of retinal immune responses and their morphological correlates in experimental autoimmune uveoretinitis (EAU), has been hindered by the requirement for post-mortem histology. To date, monitoring changes occurring during EAU disease progression and evaluating the effect of therapeutic intervention in real time has not been possible. We wanted to establish whether optical coherence tomography (OCT) could detect intraretinal changes during inflammation and to determine its utility as a tool for accurate scoring of EAU. EAU was induced in C57BL/6J mice and animals evaluated after 15, 26, 36 and 60 days. At each time-point, contemporaneous Spectralis-OCT scanning, topical endoscopic fundal imaging (TEFI), fundus fluorescein angiography (FFA) and CD45-immunolabelled histology were performed. OCT features were further characterised on retinal flat-mounts using immunohistochemistry and 3D reconstruction. Optic disc swelling and vitreous opacities detected by OCT corresponded to CD45+ cell infiltration on histology. Vasculitis identified by FFA and OCT matched perivascular myeloid and T-cell infiltrates and could be differentiated from unaffected vessels. Evolution of these changes could be followed over time in the same eye. Retinal folds were visible and found to encapsulate mixed populations of activated myeloid cells, T-cells and microglia. Using these features, an OCT-based EAU scoring system was developed, with significant correlation to validated histological (Pearson r2 = 0.6392, P<0.0001, n = 31 eyes) and TEFI based scoring systems (r2 = 0.6784, P<0.0001). OCT distinguishes the fundamental features of murine EAU in vivo, permits dynamic assessment of intraretinal changes and can be used to score disease severity. As a result, it allows tissue synchronisation with subsequent cellular and functional assessment and greater efficiency of animal usage. By relating OCT signals with immunohistochemistry in EAU, our findings offer the opportunity to inform the interpretation of OCT changes in human uveitis.

The severity of retinal pathology in homozygous Crb1rd8/rd8 mice is dependent on additional genetic factors

Understanding phenotype–genotype correlations in retinal degeneration is a major challenge. Mutations in CRB1 lead to a spectrum of autosomal recessive retinal dystrophies with variable phenotypes suggesting the influence of modifying factors. To establish the contribution of the genetic background to phenotypic variability associated with the Crb1rd8/rd8 mutation, we compared the retinal pathology of Crb1rd8/rd8/J inbred mice with that of two Crb1rd8/rd8 lines backcrossed with C57BL/6JOlaHsd mice. Topical endoscopic fundal imaging and scanning laser ophthalmoscopy fundus images of all three Crb1rd8/rd8 lines showed a significant increase in the number of inferior retinal lesions that was strikingly variable between the lines. Optical coherence tomography, semithin, ultrastructural morphology and assessment of inflammatory and vascular marker by immunohistochemistry and quantitative reverse transcriptase-polymerase chain reaction revealed that the lesions were associated with photoreceptor death, Müller and microglia activation and telangiectasia-like vascular remodelling—features that were stable in the inbred, variable in the second, but virtually absent in the third Crb1rd8/rd8 line, even at 12 months of age. This suggests that the Crb1rd8/rd8 mutation is necessary, but not sufficient for the development of these degenerative features. By whole-genome SNP analysis of the genotype–phenotype correlation, a candidate region on chromosome 15 was identified. This may carry one or more genetic modifiers for the manifestation of the retinal pathology associated with mutations in Crb1. This study also provides insight into the nature of the retinal vascular lesions that likely represent a clinical correlate for the formation of retinal telangiectasia or Coats-like vasculopathy in patients with CRB1 mutations that are thought to depend on such genetic modifiers.

Cd59a deficiency in mice leads to preferential innate immune activation in the retinal pigment epithelium–choroid with age

Dysregulation of the complement system has been implicated in the pathogenesis of age-related macular degeneration. To investigate consequences of altered complement regulation in the eye with age, we examined Cd59a complement regulator deficient (Cd59a(-/-)) mice between 4 and 15 months. In vivo imaging revealed an increased age-related accumulation of autofluorescent spots in Cd59a(-/-) mice, a feature that reflects accumulation of subretinal macrophages and/or microglia. Despite this activation of myeloid cells in the eye, Cd59a(-/-) mice showed normal retinal histology and function as well as normal choroidal microvasculature. With age, they revealed increased expression of activators of the alternative complement pathway (C3, Cfb, Cfd), in particular in the retinal pigment epithelium (RPE)-choroid but less in the retina. This molecular response was not altered by moderately-enhanced light exposure. Cd59a deficiency therefore leads to a preferential age-related dysregulation of the complement system in the RPE-choroid, that alone or in combination with light as a trigger, is not sufficient to cause choroidal vascular changes or retinal degeneration and dysfunction. This data emphasizes the particular vulnerability of the RPE-choroidal complex to dysregulation of the alternative complement pathway during aging.

Clinical and genetic characteristics of 251 consecutive patients with macular and cone/cone-rod dystrophy

Macular and cone/cone-rod dystrophies (MD/CCRD) demonstrate a broad genetic and phenotypic heterogeneity, with retinal alterations solely or predominantly involving the central retina. Targeted next-generation sequencing (NGS) is an efficient diagnostic tool for identifying mutations in patient with retinitis pigmentosa, which shows similar genetic heterogeneity. To detect the genetic causes of disease in patients with MD/CCRD, we implemented a two-tier procedure consisting of Sanger sequencing and targeted NGS including genes associated with clinically overlapping conditions. Disease-causing mutations were identified in 74% of 251 consecutive MD/CCRD patients (33% of the variants were novel). Mutations in ABCA4, PRPH2 and BEST1 accounted for 57% of disease cases. Further mutations were identified in CDHR1, GUCY2D, PROM1, CRX, GUCA1A, CERKL, MT-TL1, KIF11, RP1L1, MERTK, RDH5, CDH3, C1QTNF5, CRB1, JAG1, DRAM2, POC1B, NPHP1 and RPGR. We provide detailed illustrations of rare phenotypes, including autofluorescence and optical coherence tomography imaging. Targeted NGS also identified six potential novel genotype-phenotype correlations for FAM161A, INPP5E, MERTK, FBLN5, SEMA4A and IMPDH1. Clinical reassessment of genetically unsolved patients revealed subgroups with similar retinal phenotype, indicating a common molecular disease cause in each subgroup.

Ätiologie und Pathogenese der altersabhängigen Makuladegeneration

ZusammenfassungDie altersabhängige Makuladegeneration (AMD) ist die häufigste Ursache für eine Erblindung in Deutschland. Aufgrund der demografischen Entwicklung ist zudem mit einer deutlichen Zunahme von Betroffenen zu rechnen. Neue Erkenntnisse zur Pathogenese der AMD wurden in den letzten Jahren durch molekularbiologische Methoden generiert, die insbesondere die Assoziation genetischer Faktoren mit der AMD herausstellten. Vor allem das Komplementfaktor-H-Gen sowie der zweite Hochrisiko-Locus ARMS2 sind maßgeblich am Risiko für die Erkrankung beteiligt. Normale Alterungsprozesse und Umwelteinflüsse wie Rauchen und erhöhte Lichtexposition modulieren das individuelle genetische Risikoprofil. Ein verbessertes Verständnis der komplexen AMD-Pathogenese ist auch in der augenärztlichen Praxis notwendig, um neue Therapien zu verstehen und den Patienten adäquat zu betreuen. In diesem Fortbildungsbeitrag soll eine Übersicht über das Zusammenspiel von Altern, externen Umwelteinflüssen und genetischen Faktoren bei der Entwicklung der AMD gegeben werden.AbstractAge-related macular degeneration (AMD) is the most common cause of blindness in Germany. Due to the demographic development a further increase of affected patients is to be expected. Improved understanding of AMD pathogenesis resulted from the molecular biological approaches in recent years and showed an association of genetic factors with AMD. The complement factor H gene and the second high-risk locus ARMS2 in particular were found to contribute a significant risk for development of the disease. Ageing and environmental factors, such as smoking, modulate the individual genetic risk profile. A detailed understanding of the complex AMD pathogenesis is also relevant in ophthalmological practice to understand new treatment strategies. In this review we aim to give an overview of the interplay of ageing, external environmental factors and genetic risk variants leading to AMD.Age-related macular degeneration (AMD) is the most common cause of blindness in Germany. Due to the demographic development a further increase of affected patients is to be expected. Improved understanding of AMD pathogenesis resulted from the molecular biological approaches in recent years and showed an association of genetic factors with AMD. The complement factor H gene and the second high-risk locus ARMS2 in particular were found to contribute a significant risk for development of the disease. Ageing and environmental factors, such as smoking, modulate the individual genetic risk profile. A detailed understanding of the complex AMD pathogenesis is also relevant in ophthalmological practice to understand new treatment strategies. In this review we aim to give an overview of the interplay of ageing, external environmental factors and genetic risk variants leading to AMD.

Juvenile neuronale Zeroidlipofuszinose

Neuronal ceroid lipofuscinoses (NCL) are a heterogeneous group of neurodegenerative diseases with mostly autosomal recessive inheritance whose common feature is the intralysosomal accumulation of ceroid lipofuscin. With varying manifestation ages the diseases result in cognitive and motor deterioration, epilepsy, diffuse retinal degeneration, and eventually death. Juvenile ceroid lipofuscinosis (JNCL, CLN3, Batten disease) has the distinctive feature that the ophthalmologic symptoms precede the neurologic symptoms by several years, and thus the ophthalmologist plays a central role in early diagnosis. Important clinical signs of JNCL include bulls eye maculopathy, severely reduced Ganzfeld ERG already at initial presentation, and unusually rapid progression of the functional decline. If JNCL is clinically suspected the diagnosis can be made by means of a standard blood smear and confirmed by genetic detection of the mutation. Although causal therapeutic options are currently only in the developmental stage, early diagnosis by the ophthalmologist is of utmost importance to allow for medical and educational support of the affected child and for adequate counseling of the parents.ZusammenfassungDie neuronalen Zeroidlipofuszinosen („neuronal ceroid lipofuscinoses“, NCL) sind eine heterogene Gruppe meist autosomal-rezessiv vererbter, neurodegenerativer Erkrankungen, deren gemeinsames Merkmal die intralysosomale Akkumulation von Zeroidlipofuszin ist. Mit unterschiedlichem Manifestationsalter kommt es zu kognitivem und motorischem Abbau, Epilepsie, diffuser Netzhautdegeneration und schließlich zum Tod. Die juvenile NCL (JNCL, CLN3, Spielmeyer-Vogt-Krankheit), die in der Regel im frühen Schulalter manifest wird, hat die Besonderheit, dass die ophthalmologischen Symptome den neurologischen um einige Jahre vorausgehen, so dass hier dem Augenarzt die Aufgabe der Erstdiagnose zukommt. Wichtige klinische Zeichen für eine JNCL sind die Schießscheibenmakulopathie, das bereits bei Erstvorstellung stark reduzierte Ganzfeld-ERG und die ungewöhnlich rasche Progredienz der Sehverschlechterung. Bei entsprechendem Verdacht kann die Diagnose anhand eines Blutausstrichs gestellt und mittels molekulargenetischem Nachweis der Mutation gesichert werden. Auch wenn sich kausale Therapiemöglichkeiten momentan erst im Entwicklungsstadium befinden, ist eine frühzeitige Diagnosestellung durch den Augenarzt für die medizinische und pädagogische Betreuung des betroffenen Kindes und die angemessene Beratung der Eltern von größter Bedeutung.AbstractNeuronal ceroid lipofuscinoses (NCL) are a heterogeneous group of neurodegenerative diseases with mostly autosomal recessive inheritance whose common feature is the intralysosomal accumulation of ceroid lipofuscin. With varying manifestation ages the diseases result in cognitive and motor deterioration, epilepsy, diffuse retinal degeneration, and eventually death. Juvenile ceroid lipofuscinosis (JNCL, CLN3, Batten disease) has the distinctive feature that the ophthalmologic symptoms precede the neurologic symptoms by several years, and thus the ophthalmologist plays a central role in early diagnosis. Important clinical signs of JNCL include bull’s eye maculopathy, severely reduced Ganzfeld ERG already at initial presentation, and unusually rapid progression of the functional decline. If JNCL is clinically suspected the diagnosis can be made by means of a standard blood smear and confirmed by genetic detection of the mutation. Although causal therapeutic options are currently only in the developmental stage, early diagnosis by the ophthalmologist is of utmost importance to allow for medical and educational support of the affected child and for adequate counseling of the parents.

[Etiology and pathogenesis of age-related macular degeneration].

ZusammenfassungDie altersabhängige Makuladegeneration (AMD) ist die häufigste Ursache für eine Erblindung in Deutschland. Aufgrund der demografischen Entwicklung ist zudem mit einer deutlichen Zunahme von Betroffenen zu rechnen. Neue Erkenntnisse zur Pathogenese der AMD wurden in den letzten Jahren durch molekularbiologische Methoden generiert, die insbesondere die Assoziation genetischer Faktoren mit der AMD herausstellten. Vor allem das Komplementfaktor-H-Gen sowie der zweite Hochrisiko-Locus ARMS2 sind maßgeblich am Risiko für die Erkrankung beteiligt. Normale Alterungsprozesse und Umwelteinflüsse wie Rauchen und erhöhte Lichtexposition modulieren das individuelle genetische Risikoprofil. Ein verbessertes Verständnis der komplexen AMD-Pathogenese ist auch in der augenärztlichen Praxis notwendig, um neue Therapien zu verstehen und den Patienten adäquat zu betreuen. In diesem Fortbildungsbeitrag soll eine Übersicht über das Zusammenspiel von Altern, externen Umwelteinflüssen und genetischen Faktoren bei der Entwicklung der AMD gegeben werden.AbstractAge-related macular degeneration (AMD) is the most common cause of blindness in Germany. Due to the demographic development a further increase of affected patients is to be expected. Improved understanding of AMD pathogenesis resulted from the molecular biological approaches in recent years and showed an association of genetic factors with AMD. The complement factor H gene and the second high-risk locus ARMS2 in particular were found to contribute a significant risk for development of the disease. Ageing and environmental factors, such as smoking, modulate the individual genetic risk profile. A detailed understanding of the complex AMD pathogenesis is also relevant in ophthalmological practice to understand new treatment strategies. In this review we aim to give an overview of the interplay of ageing, external environmental factors and genetic risk variants leading to AMD.Age-related macular degeneration (AMD) is the most common cause of blindness in Germany. Due to the demographic development a further increase of affected patients is to be expected. Improved understanding of AMD pathogenesis resulted from the molecular biological approaches in recent years and showed an association of genetic factors with AMD. The complement factor H gene and the second high-risk locus ARMS2 in particular were found to contribute a significant risk for development of the disease. Ageing and environmental factors, such as smoking, modulate the individual genetic risk profile. A detailed understanding of the complex AMD pathogenesis is also relevant in ophthalmological practice to understand new treatment strategies. In this review we aim to give an overview of the interplay of ageing, external environmental factors and genetic risk variants leading to AMD.

Juvenile neuronal ceroid lipofuscinosis. Ophthalmologic findings and differential diagnosis

Neuronal ceroid lipofuscinoses (NCL) are a heterogeneous group of neurodegenerative diseases with mostly autosomal recessive inheritance whose common feature is the intralysosomal accumulation of ceroid lipofuscin. With varying manifestation ages the diseases result in cognitive and motor deterioration, epilepsy, diffuse retinal degeneration, and eventually death. Juvenile ceroid lipofuscinosis (JNCL, CLN3, Batten disease) has the distinctive feature that the ophthalmologic symptoms precede the neurologic symptoms by several years, and thus the ophthalmologist plays a central role in early diagnosis. Important clinical signs of JNCL include bulls eye maculopathy, severely reduced Ganzfeld ERG already at initial presentation, and unusually rapid progression of the functional decline. If JNCL is clinically suspected the diagnosis can be made by means of a standard blood smear and confirmed by genetic detection of the mutation. Although causal therapeutic options are currently only in the developmental stage, early diagnosis by the ophthalmologist is of utmost importance to allow for medical and educational support of the affected child and for adequate counseling of the parents.ZusammenfassungDie neuronalen Zeroidlipofuszinosen („neuronal ceroid lipofuscinoses“, NCL) sind eine heterogene Gruppe meist autosomal-rezessiv vererbter, neurodegenerativer Erkrankungen, deren gemeinsames Merkmal die intralysosomale Akkumulation von Zeroidlipofuszin ist. Mit unterschiedlichem Manifestationsalter kommt es zu kognitivem und motorischem Abbau, Epilepsie, diffuser Netzhautdegeneration und schließlich zum Tod. Die juvenile NCL (JNCL, CLN3, Spielmeyer-Vogt-Krankheit), die in der Regel im frühen Schulalter manifest wird, hat die Besonderheit, dass die ophthalmologischen Symptome den neurologischen um einige Jahre vorausgehen, so dass hier dem Augenarzt die Aufgabe der Erstdiagnose zukommt. Wichtige klinische Zeichen für eine JNCL sind die Schießscheibenmakulopathie, das bereits bei Erstvorstellung stark reduzierte Ganzfeld-ERG und die ungewöhnlich rasche Progredienz der Sehverschlechterung. Bei entsprechendem Verdacht kann die Diagnose anhand eines Blutausstrichs gestellt und mittels molekulargenetischem Nachweis der Mutation gesichert werden. Auch wenn sich kausale Therapiemöglichkeiten momentan erst im Entwicklungsstadium befinden, ist eine frühzeitige Diagnosestellung durch den Augenarzt für die medizinische und pädagogische Betreuung des betroffenen Kindes und die angemessene Beratung der Eltern von größter Bedeutung.AbstractNeuronal ceroid lipofuscinoses (NCL) are a heterogeneous group of neurodegenerative diseases with mostly autosomal recessive inheritance whose common feature is the intralysosomal accumulation of ceroid lipofuscin. With varying manifestation ages the diseases result in cognitive and motor deterioration, epilepsy, diffuse retinal degeneration, and eventually death. Juvenile ceroid lipofuscinosis (JNCL, CLN3, Batten disease) has the distinctive feature that the ophthalmologic symptoms precede the neurologic symptoms by several years, and thus the ophthalmologist plays a central role in early diagnosis. Important clinical signs of JNCL include bull’s eye maculopathy, severely reduced Ganzfeld ERG already at initial presentation, and unusually rapid progression of the functional decline. If JNCL is clinically suspected the diagnosis can be made by means of a standard blood smear and confirmed by genetic detection of the mutation. Although causal therapeutic options are currently only in the developmental stage, early diagnosis by the ophthalmologist is of utmost importance to allow for medical and educational support of the affected child and for adequate counseling of the parents.