<p>Transforming growth factor β-activated kinase 1 (TAK1), a hub kinase at the convergence of multiple signaling pathways, is critical to the development of the central nervous system and has been found to play a role in cell death and apoptosis. TAK1 may have the potential to elucidate mechanisms of cell cycle and neurodegeneration. The Belecky-Adams laboratory has aimed to study TAK1 and its potential roles in cell cycle by studying its role in chick retinal development as well as its possible implication in the progression of diabetic retinopathy (DR). Chapter 3 includes studies that explore TAK1 in a study in chick retinal development and TAK1 in in vitro studies in retinal microglia. Using the embryonic chick, immunohistochemistry for the activated form of TAK1 (pTAK1) showed localization of pTAK1 in differentiated and progenitor cells of the retina. Using an inhibitor or TAK1 activite, (5Z)-7-Oxozeaenol, in chick eye development showed an increase in progenitor cells and a decrease in differentiated cells. This study in chick suggests TAK1 may be a critical player in the regulation of the cell cycle during retinal development. Results from experimentation in chick led to studying the potential role of TAK1 in inflammation and neurodegeneration. TAK1 has previously been implicated in cell death and apoptosis suggesting that TAK1 may be a critical player in inflammatory pathways. TAK1 has been implicated in the regulation of inflammatory factors in different parts of the CNS but has not yet been studied specifically in retina or in specific retinal cells [3, 4]. Chapter 2 includes studies from the Belecky-Adams laboratory of in vitro work with retinal microglia. Retinal microglia were treated with activators and the translocation to the nucleus of a downstream factor of TAK1 was determined: NF-kB. Treatment of retinal microglia in the presence of activators with TAKinib, an inhibitor of TAK1 activation, revealed that TAK1 inhibition reduces the activation of downstream NF-kB. Together this data suggests that TAK1 may be implicated in various systems of the body and further studies on its mechanisms may help elucidate potential therapeutic roles of the kinase.</p>

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La rétinopathie diabétique est une cause majeure de cécité et de malvoyance qui affecte jusqu'à 90% des patients atteints de diabète. Le Maroc n’échappe pas à cette pathologie, qui est connue pour altérer le fonctionnement du système visuel et pourrait conduire également à des désordres chronobiologiques, aussi bien chez l’Homme que chez des modèles animaux. Ces altérations pourraient être liées aux dégénérescences neuronales des systèmes de photoréception classique (cône et bâtonnet) et des cellules ganglionnaires à mélanopsine, impliqués dans la régulation et l’entraînement par la lumière du système circadien. Cependant, à l’heure actuelle, peu d’études ont analysé précisément l’impact de la rétinopathie diabétique sur le système circadien. L’objectif de notre travail est d’analyser au cours de la rétinopathie diabétique (1) l’atteinte des cônes, des bâtonnets et des cellules ganglionnaires à mélanopsine, (2) le fonctionnement endogène moléculaire et la réponse à la lumière des horloges centrale et rétinienne et (3) la réponse comportementale du système circadien à la lumière. Notre stratégie est basée sur l’utilisation d’un modèle murin, chez lequel le diabète est induit expérimentalement par l’administration d’un agent chimique la streptozotocine (STZ), toxique pour les cellules β pancréatiques. Des approches morphométriques, moléculaires et comportementales ont été utilisées. Nos résultats montrent que le diabète induit des changements morphologiques des cellules ganglionnaires à mélanopsine tels que des gonflements des somas et des varicosités au niveau des dendrites avec une préservation du nombre total de ces cellules. Ceci est associé à une diminution de l’induction par la lumière du gène c-fos et des gènes de l’horloge Per1 et Per2 au niveau du SCN et à l’absence de cette induction au niveau rétinien au stade 12 semaines après l’induction du diabète. La machinerie moléculaire des horloges rétinienne et centrale évaluée par l’analyse de l’expression circadienne des gènes de l’horloge et des gènes contrôlés par les gènes de l’horloge montre que certains gènes de l’horloge clés pour chaque tissu sont altérés. A l’échelle comportementale, les souris STZ (souris diabétiques) montrent une réduction de l’amplitude du rythme de leur activité locomotrice totale et une diminution de la sensibilité à la lumière aux faibles intensités. Après une avance de phase du cycle 12L/12D, ces animaux présentent également une diminution de la vitesse de resynchronisation au nouveau cycle lumineux imposé par rapport aux animaux témoins. Ces nouvelles données montrent que le diabète de type 1 altère les réponses du système circadien à la lumière d’un point de vue moléculaire et comportemental et suggèrent que les patients diabétiques peuvent présenter des troubles circadiens particulièrement lorsqu’ils sont soumis aux challenges chronobiologiques / Diabetic retinopathy is a major cause of blindness and is commonly viewed as a vascular complication of type 1 diabetes. However, this kind of diabetes causes visual dysfunction before the onset of clinically visible microvascular changes, associated with diabetic retinopathy. Several histopathological studies in diabetic patients and in chemically-induced or genetic rodent models of diabetes indicate that photoreceptors and retinal ganglion cells (RGCs) are affected by diabetes with apoptotic degeneration. There is increasing evidence that melanopsin-expressing ganglion cells that are crucial for the regulation of a range of non-visual functions including the photic synchronization of circadian rhythms are altered in retinal pathologies. The link between diabetes and circadian rhythms has only been addressed in a relatively limited number of studies. Using a streptozotocin-induced (STZ) model of diabetes, we investigated the impact of diabetic retinopathy on non-visual functions by analyzing the morphology of melanopsin ganglion cells and light-induced c-fos and Period 1-2 clock genes in the central (SCN) and the retina clocks. The effect of this pathology on the endogenous circadian function of clock and controlled clock genes was assessed in the SCN and the retina at 12 weeks post-diabetes. Behaviorally, the ability of STZdiabetic mice to entrain to light was challenged by the exposure of animals to 1) successive light/dark (LD) cycle of decreasing or increasing light intensities during the light phase and 2) 6-hr advance of the LD cycle. Our results show that diabetes induces morphological changes of melanopsin-expressing ganglion cells including soma swelling and dendritic varicosities with no reduction in their total number, associated with decreased c-fos and clock genes induction by light in the SCN and also in the retina at 12 weeks post-onset of diabetes. In addition, the circadian expression of major clock genes was altered in the central and retinal clocks, suggesting that RD affects the endogenous molecular machinery and the light response of these two clocks. Moreover, STZ-diabetic mice exhibited a reduction of overall locomotor activity, a decrease of circadian sensitivity to light at low intensities, and a delay in the time to re-entrain after a phase advance of the LD cycle. These novel findings demonstrate that diabetes alters clock genes and behavioral responses of the circadian timing system to light and suggest that diabetic patients may show an increased propensity for circadian disturbances, in particular when they are exposed to chronobiological challenges

This report contains a summation of a variety of articles that have been read and analysed. Each article describes different methods that can be used to detect lesions, optic disks, drusen and exudates in retinal images. I.e. diagnose e.g. Diabetic Retinopathy and Age-Related Macular Degeneration. A general approach is presented, which all methods more or less is based on. Methods to locate the optic disk The PCA  kNN Regression Hough Transform Fuzzy Convergence Vessel Direction Matched Filter Etc. The best method based on result, reliability, number of images and publisher is kNN regression. The result of this method is remarkably good and that brings some doubt about its reliability. Though the method was published at IEEE and that gives the method a more trustful look. A next best method which also is very useful is Vessel Direction Matched Filter. Methods to detect drusen – diagnose Age-Related Macular Degeneration PNN classifier Histogram approach Etc. The best method based on result, reliability, number of images and publisher is the PNN classifier. The method had a sensitivity of 94 % and a specificity of 95 %. 300 images were used in the experiment which was published by the IEEE in 2011. Methods to detect exudates – diagnose Diabetic Retinopathy Morphological techniques Luv colour space, Wiener filter an Canny edge detector. The best method based on result, reliability, number of images and publisher is an experiment called “Feature Extraction”. The method includes the Luv colour space, Wiener filter (remove noise) and the Canny edge detector. / Den här rapporten innehåller en sammanfattning av ett flertal artiklar som har blivit studerade. Varje artikel har beskrivit en metod som kan användas för att upptäcka sjuka förändringar i ögonbottenbilder, det vill säga, åldersförändringar i gula fläcken och diabetisk retinopati. Metoder för att lokalisera blinda fläcken PCA kNN regression Hough omvandling Suddig konvergens Filtrering beroende på kärlens riktning Mm. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är kNN regression. De förvånansvärt goda resultaten kan inbringa lite tvivel på huruvida resultaten stämmer. Artikeln publicerades dock av IEEE och det gör artikeln mer trovärdig. Den näst bästa metoden är filtrering beroende på kärlens riktning. Metoder för att diagnosticera åldersförändringar i gula fläcken PNN klassificeraren Histogram Mm. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är PNN klassificeraren. Metoden hade en sensitivitet på 94 % och en specificitet på 95 %. 300 bilder användes i experimentet som publicerades av IEEE år 2011. Metoder att diagnosticera diabetisk retinopati Morfologiska tekniker Luv colour space, Wiener filter and Canny edge detector. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är ett experimentet som heter ”Feature Extraction”. Experimentet inkluderar Luv colour space, Wiener filter (brus borttagning) och Canny edge detector

Ischemic retinopathies (IR) are vision-threatening diseases that affect a substantial amount of people across all age groups worldwide. The current treatment options of photocoagulation and anti-VEGF therapy have side effects and are occasionally unable to prevent disease progression. It is therefore worthwhile to consider other molecular targets for the development of novel treatment strategies that could be safer and more efficient. During the manifestation of IR, the retina, normally an immune privileged tissue, encounters enhanced levels of cellular stress and inflammation that attract mononuclear phagocytes (MPs) from the blood stream and activate resident MPs (microglia). Activated MPs have a multitude of effects within the retinal tissue and have the potential to both counter and exacerbate the harmful tissue microenvironment. The present review discusses the current knowledge about the role of inflammation and activated retinal MPs in the major IRs: retinopathy of prematurity and diabetic retinopathy. We focus particularly on MPs and their secreted factors and cell–cell-based interactions between MPs and endothelial cells. We conclude that activated MPs play a major role in the manifestation and progression of IRs and could therefore become a promising new target for novel pharmacological intervention strategies in these diseases.

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Ziel dieser Arbeit war es, in Querschnitts- und prospektiven Longitudinalstudien die Diagnostik diabetes-assoziierter Autoimmunerkrankungen (Autoimmun-Thyreoiditis und Zöliakie, primäre Komorbiditäten) sowie diagnostische Verfahren zur Früherkennung von sekundären Spätkomplikationen (Retinopathie und Nephropathie, sekundäre Komorbiditäten) bei Kindern und Jugendlichen mit Typ 1 Diabetes zu evaluieren. Mit Hilfe eines Screenings spezifischer Antikörper (EmA, IgA-Gliadin-, IgA-tTG-Antikörper) konnte eine höhere als bisher berichtete Zöliakie-Prävalenz bei zwei Prozent der asymptomatischen Kinder mit Typ 1 Diabetes festgestellt werden. Eine Autoimmun-Thyreoiditis wurde durch Untersuchungen von Schilddrüsen-spezifischen Antikörpern (Anti-TPO, Anti-TG) bei bis zu 20 Prozent der Kinder und Jugendlichen diagnostiziert. Mädchen hatten signifikant häufiger Schilddrüsen-Antikörper als Jungen. Mit zunehmendem Alter der Patienten stieg die Prävalenz der Antikörper. Die Anwesenheit positiver Schilddrüsen-Antikörper war mit höheren TSH-Werten assoziiert. Sehr hohe Schilddrüsen-Antikörper (Anti-TPO, Anti-TG) waren prädiktiv für die spätere Entwicklung einer subklinischen Hypothyreose. Hinsichtlich der sekundären Komorbiditäten konnte anhand von Messungen der glomerulären (Alb, Tf, IgG) und tubulären Marker (NAG, alpha1-MG) nachgewiesen werden, dass bei Patienten mit Diabetes nicht nur eine glomeruläre, sondern auch eine tubuläre renale Dysfunktion vorliegen kann. Eine erhöhte NAG-Urinausscheidung war prädiktiv für die Entwicklung einer Mikroalbuminurie. Für die Retinopathieentwicklung war die Stoffwechseleinstellung (HbA1c) von wesentlicher Bedeutung, insbesondere während der ersten Diabetesjahre. In der Pubertät kam es zu einer Beschleunigung der Retinopathieentwicklung. Weitere Risikofaktoren für sekundäre Spätkomplikationen insbesondere Retinopathie waren Blutdruck, Lipidstoffwechsel (Triglyzeride, HDL-Cholesterin) und Gesamtrenin. Für die Prognose und Prävention primärer und sekundärer Komorbiditäten bei Kindern mit einem Typ 1 Diabetes als chronische Grunderkrankung ist ein frühzeitiges und regelmäßiges Screening von wesentlicher Bedeutung. / The aim of this study was the evaluation of diagnostic procedures for the early detection of diabetes-associated autoimmune diseases (autoimmune thyroiditis and coeliac disease, primary co-morbidity) as well as of diabetes-specific late complications (retinopathy and nephropathy, secondary co-morbidity) in children and adolescents with type 1 diabetes. The prevalence of coeliac disease among asymptomatic children with type 1 diabetes was 2 percent based on a screening for specific autoantibodies (EMA, IgA-gliadin-, IgA-tTG-antibodies) being higher than reported previously. Autoimmune thyroiditis was diagnosed in up to 20 percent of children and adolescents according to screening procedures for thyroid-specific antibodies (anti-TPO, anti-TG). Girls had more frequently thyroid antibodies than boys. The prevalence of thyroid antibodies increased with increasing age of patients. The presence of thyroid antibodies was associated with higher TSH values, while very high values of thyroid antibodies were predictive for the development of a subclinical hypothyroidism. Studies concerning the prevalence of secondary co-morbidity in young patients with type 1 diabetes revealed that not only glomerular, but also tubular renal dysfunction may occur in these patients. These studies based on the measurement of urinary excretion of glomerular (Alb, Tf, IgG) and tubular (NAG, alpha1-MG) markers. Elevated urinary excretion of NAG was predictive for the development of microalbuminuria. Glycaemic control (HbA1c), particularly during the first years of diabetes, constituted a significant parameter for the development of retinopathy, while puberty may accelerate the development of this late complication. Arterial blood pressure, lipid profile (triglycerides, HDL-cholesterol) and total renin had been found to be additional risk factors for the development of late complications, particularly retinopathy. An early and regularly performed screening is recommended for the prognosis and prevention of primary and secondary co-morbidity in children with type 1 diabetes.

La rétinopathie induite par l’oxygène (RIO) est un modèle animal semblable aux rétinopathies vue chez l’homme. Dans ce modèle, une destruction des microvaisseaux rétiniens est suivie d’une néovascularisation pathologique qui chez l’homme peut mener à un détachement de la rétine et subséquemment une perte de vision. Afin de remédier à cette revascularisation anarchique, un traitement de cellules souches (hématopoïétiques et mésenchymateuses) a été effectué chez des souris soumises à ce modèle. Les cellules injectées ont pu migrer à la rétine et induire une revascularisation saine (surtout les cellules souches mésenchymateuses). L’injection du milieu de culture de ces cellules induit aussi une revascularisation semblable à celle vue chez les souris traitées avec les cellules indiquant que l’effet thérapeutique des cellules semble être accompli par l’entremise de facteurs paracrines. Ces résultats suggèrent que ces cellules peuvent jouer un rôle au niveau de l’angiogénèse et indiquent un potentiel thérapeutique pour les rétinopathies. / Oxygen induced retinopathy (OIR) is an animal model that mimics the developing phases of retinopathies seen in humans such as diabetic retinopathy and retinopathy of prematurity. An initial destruction of retinal microvasculature is followed by pathological neovascularization that can lead to retinal detachment in humans and therefore blindness. Utilizing bone marrow derived stem cells (mesenchymal and hematopoietic), we aimed to repopulate the retina with normal vessels which are affected in the OIR model. Cells injected into the vitreous migrated to the retina and reduced both the area of vasoobliteration and neovascularization. Injection of conditioned cell medium also induced proper vascular repair similar to that seen in mice injected with cells indicating that the cells therapeutic effect is achieved through paracrine action. These results suggest that bone marrow stem cells play a role in angiogenesis and could be a potential therapeutic aid in treating retinopathies.