No description available.

No description available.

Abstract The markers of microvascular complications of type 1 diabetes were evaluated in adolescents in a cross sectional survey of 100 out of 138 eligible patients aged 9-19 years with a duration of diabetes over two years who visited the Paediatric Outpatient Clinic at Oulu University Hospital in 1997-1999, and one hundred healthy controls. Two patients in early or mid-puberty had non-proliferative diabetic retinopathy, but no other signs of microvascular complications. The five patients with persistent microalbuminuria were all girls; one prepubertal, one late pubertal and three postpubertal. Their mean glycated haemoglobin A1c (HbA1c) was higher, but they had a similar duration of diabetes and age distribution to those without microalbuminuria. The adolescent patients were predisposed to higher fasting serum total and low-density lipoprotein cholesterol and triglyceride levels and higher diastolic blood pressure than the control subjects. The proportional total body fat was highest in the girls with diabetes by the end of puberty, while serum leptin levels did not differ between the patients and healthy controls. The patients had low fasting serum insulin levels and high insulin-like growth factor-binding protein 1 levels, related to hypoinsulinaemia. Distal motor nerve function in the lower extremities were already affected before puberty, and distal and proximal nerve function deteriorated as puberty advanced. Ten patients had neurophysiologically confirmed distal diabetic polyneuropathy, and they were older and they had longer duration of diabetes and higher HbA1c than patients without polyneuropathy. Although cardiovascular function was in the main well preserved in the adolescents with type 1 diabetes, the power spectrum analysis of heart rate variability showed attenuated autonomic nervous system reactivity. Taken together these data show that a relatively small proportion of adolescents with type 1 diabetes have signs of microvascular complications. The prevalences of diabetic retinopathy, persistent microalbuminuria and distal diabetic polyneuropathy were 2%, 6% and 10%, respectively. Pubertal maturation seems to promote the progression of early signs of microvascular complications in patients affected by type 1 diabetes.

Atypical hemolytic uremic syndrome (aHUS) is a rare renal disorder characterized by thrombotic microangiopathy, thrombocytopenia, and acute kidney injury. Its pathogenesis has been attributed to a ‘triggering' event that leads to dysregulation of the complement cascade at the level of the endothelial cell surface. Consistent with this understanding of the disease, mutations in complement genes have been definitively implicated in aHUS. However, the existence of other genetic contributors is supported by two observations. First, in ~50% of cases, disease-causing variants are not identified in complement genes, and second, disease penetrance is typically incomplete and highly variable. To test this hypothesis, we identified pathways established to have crosstalk with the complement cascade, focusing initially on the coagulation pathway. Using targeted genomic enrichment and massively parallel sequencing we screened 36 European-American patients with sporadic aHUS patients for genetic variants in 85 complement and coagulation genes, identifying deleterious rare variants in several coagulation genes. The most frequently mutated coagulation gene in our study cohort was PLG, which encodes a zymogen of plasmin and plays key role in fibrinolysis. These results implicate the coagulation pathway in the pathogenesis of aHUS. Based on this outcome, we developed a clinical genetic testing panel to screen disease-related genes in a group of ultra-rare complement-mediated diseases that includes, in addition to aHUS, thrombotic thrombocytopenic purpura (TTP), C3 glomerulonephritis (C3GN) and dense deposit disease (DDD) patients. Data from 193 patients validate the usage of this panel in clinical practice and also provide confirmatory insight into the pathogeneses of these diseases. Specifically, we found that in aHUS and TTP patients, variants were frequently identified in complement regulator genes, while in C3GN and DDD patients, variants were additionally found in C3 convertase genes. To understand variability in disease penetrance, we completed targeted genetic screening in two aHUS families grossly discordant for disease penetrance, identifying in one family a co-segregating Factor X-deficiency variant (F10 p.Glu142Lys) that abrogated the effect of the complement mutation. Functional studies of the F10 p.Glu142Lys variant show that it decreases Factor X activity predicting to a hypo-coagulable state and further illustrating the importance of complement-coagulation crosstalk in exacerbating, but also mitigating the aHUS phenotype. In our final studies, we have sought to complete a comprehensive analysis for other potentially related pathways by using bioinformatics to identify candidate pathways coupled with whole exome sequencing. Preliminary data from 43 aHUS patients and 300 controls suggest that pathways for dermatan and heparan sulfate synthesis, which are relevant to the formation of the extra-cellular matrix and cell surface adhesion, may be implicated in the aHUS.

Granulocyte colony-stimulating factor (GCSF) is currently the most widely used cytokine for stem cell mobilization. There are few studies suggesting GCSF administration may induce activation of both coagulation and endothelial cells that could favor the developing of thrombotic events. We report a 58-year-old female with vasculitis and renal impairment. She was found to have an underlying monoclonal gammopathy of unknown significance (MGUS). The monoclonal protein was felt to play a role in her underlying renal disease and peripheral neuropathy. She was considered a candidate for peripheral blood stem cell transplantation to manage the monoclonal protein. During stem cell mobilization with GCSF, she developed worsening of anemia; thrombocytopenia and worsening of renal function. She was diagnosed with thrombotic microangiopathy (TMA) which was successfully treated with therapeutic plasma exchange and rituximab. It is possible that GCSF may have directly (activating endothelial cells) or indirectly (activation of underlying autoimmune disorder) contributed to TMA in this patient.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18857号 / 医博第3968号 / 新制||医||1008(附属図書館) / 31808 / 京都大学大学院医学研究科医学専攻 / (主査)教授 前川 平, 教授 江藤 浩之, 教授 河本 宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Le syndrome hémolytique et urémique atypique (SHUa) est une microangiopathie thrombotiquecomplément-dépendante dont l'atteinte majoritairement rénale reste, à ce jour, incomprise.L'objectif de ce travail était d'améliorer la compréhension de ce tropisme d’organe au moyen dedeux axes d'étude : i) la susceptibilité de l'endothélium glomérulaire à l'hémolyse, celle-ci étant à la fois la conséquence des microthromboses dans le SHUa et un amplificateur de la voie alterne du complément via l'hème libre, molécule issue des globules rouges lysés ; ii) le rôle potentiel du récepteur aux produits de glycation avancés ou RAGE. Ce récepteur membranaire aux fortes propriétés pro inflammatoires et pro thrombotiques a en effet été impliqué dans de nombreuses pathologies rénales, et sa liaison au C3a - anaphylatoxine libérée dans l'activation du complément - a été rapportée par une équipe.La première partie de ce travail a visé à expliquer la vulnérabilité de l'endothélium glomérulaire sous l'effet d'une hémolyse. Nous avons étudié plusieurs types de cellules endothéliales exposées +/- à l'hème, et mis au point un modèle murin traité par de l'hème. En conditions hémolytiques, plusieursfacteurs pouvant participer à cette susceptibilité endothéliale glomérulaire ont ainsi été mis en avant: i) une moindre liaison du facteur H, principal régulateur du complément, à sa surface ; ii) une faible expression de la thrombomoduline, protéine de la coagulation et régulatrice du complément ; iii) une faible expression de l'enzyme principale de dégradation de l'hème, l'hème-oxygénase 1. Ces deux derniers points étaient rattachés à une faible induction endothéliale glomérulaire de leurs facteurs de transcription, KFL2 et KLF4.La seconde partie de ce travail s'est concentrée sur le RAGE. N'ayant pas réussi à reproduire l'interaction RAGE/C3a, nous avons exploré l'hypothèse d'une liaison du RAGE à l'hème. En effet, le seul récepteur endothélial connu jusqu'à présent est le Toll Like Receptor 4 (TLR4), qui partage plusieurs ligands communs avec le RAGE (LPS - lipopolysaccharide, HMGB1 - high–mobility group box1). Nous avons découvert que le RAGE était un récepteur de l'hème, et identifié que le site de liaisonse trouvait sur le domaine V. A l'aide d'un modèle murin invalidé pour le RAGE et traité +/- par l'hème, nous avons mis en évidence que : i) l'invalidation de RAGE avait un effet protecteur en cas d’exposition à l'hème, marqué par une diminution de l'expression de gènes de l'inflammation (IL1β,TNFα) et du facteur tissulaire au niveau pulmonaire, organe exprimant le plus fortement RAGE ; ii)l'hème activait la phosphorylation des voies ERK1/2 et Akt via le RAGE.Par ces travaux, nous avons précisé les liens entre activation du complément, hémolyse et susceptibilité endothéliale glomérulaire dans le SHUa. Parallèlement, nous avons identifié le RAGE comme un nouveau récepteur à l'hème, dont la liaison à ce récepteur activerait différentes voies designalisation de l'inflammation. Le contrôle de l'hème et du RAGE pourrait ainsi constituer de nouvelles voies thérapeutiques dans le SHUa et les maladies hémolytiques. / The atypical haemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy of which the predominantly renal damage remains, to date, misunderstood. The aim of this work was to improve the understanding of this organ tropism by two axes of study: i) the susceptibility of the glomerular endothelium to hemolysis, which is the consequence of microthrombosis in aHUS, and also an complement pathway enhancer via free heme, hemoglobin-mediated hemolysis molecule, ii) the potential role of the receptor for advanced glycation end products, RAGE. Indeed, RAGE is described as an endothelial receptor with high proinflammatory and prothrombotic potential, involved in many kidney diseases; a team also reported that it was a receptor for the C3a molecule, anaphylatoxin released in complement activation.The first part of this work aimed to explain the vulnerability of the glomerular endothelium under the effect of hemolysis. We studied several types of endothelial cells exposed +/- to heme, and developed a murine model treated with heme. In hemolytic conditions, several factors that could participate in the endothelial glomerular susceptibility have been put forward: i) less binding of factor H, the main complement regulator, on its surface; ii) low expression of thrombomodulin, coagulation protein and complement regulator; iii) low expression of heme-oxygenase 1, the main heme degradation enzyme. These last two points were related to low induction, on glomerular endothelial cells, of transcription factors, KFL2 and KLF4.The second part of this work focused on RAGE. Having failed to reproduce the RAGE / C3a interaction, we explored the hypothesis of a linkage of RAGE to heme. Indeed, the only known endothelial receptor is Toll Like Receptor 4 (TLR4), which shares several common ligands (LPS - lipopolysaccharide, HMGB1 - high-mobility group box 1). We found that RAGE was a heme receptor, and identified that the binding site was on domain V. Using a mouse model knock out for RAGE and treated +/- with heme, we demonstrated that i) the invalidation of RAGE had a protective effect in case of exposure to heme, marked by a decrease in the expression of genes of inflammation (IL1β; TNFα; and tissue factor) at the pulmonary level, organ expressing most strongly RAGE, ii) the heme is an activator or the phosphorylation of ERK1 / 2 and Akt pathways via RAGE.Through this work, we have clarified the links between complement activation, hemolysis and glomerular endothelial susceptibility in aHUS. At the same time, we have identified RAGE as a new heme receptor, whose RAGE/heme bindind would activate different signaling pathways for inflammation. The control of heme and RAGE could constitute new therapeutic pathways in the aHUS, and hemolytic diseases.

No description available.

Das Auftreten manifester transplantationsassoziierter thrombotischer Mikroangiopathie sowie das Auftreten leichterer, zumeist subklinischer mikroangiopathischer Veränderungen wurde in einem Kollektiv von Patienten untersucht, die zur Behandlung einer steroidrefraktären oder abhängigen akuten oder chronischen GvHD nach allogener Stammzelltransplantation eine Therapie mit extrakorporalen Photopheresen erhielten. Subklinische mikroangiopathische Schädigung wurde durch ein auf den Messwerten von Fragmentozyten, Thrombozyten sowie der LDH-Aktivität beruhendes Bewertungsschema festgestellt. Das Auftreten von ausgeprägten mikroangiopathischen Veränderungen (Schweregrad 2) ging mit einem erniedrigten Gesamtüberleben einher. Die Reduktion der Steroiddosis und die Verringerung der GvHD-Manifestationen wurden als Parameter für die Wirksamkeit der ECP analysiert. Ihre Effektivität wurde bestätigt. Trotz der nachgewiesenen Effektivität der ECP in der Kontrolle der GvHD zeigte sich eine Tendenz zur Zunahme mikroangiopathischer Veränderungen unter Therapie mit ECP, in Einzelfällen mit schwerwiegenden klinischen Konsequenzen.

The diagnosis of Multiple Sclerosis (MS) is primarily based on the clinical examination, while it is supported by Magnetic Resonance (MR) imaging evaluated by experienced radiologists. Although, the typical imaging characteristics of MS follow well documented patterns, there are other pathologies affecting the Central Nervous System (CNS) that resemble the imaging characteristics of MS and vice versa. Cerebral Microangiopathy (CM) belongs to such pathologies that may puzzle the radiologist regarding his/her final decision. The differential diagnosis problem usually arises at the onset of the disease, when there is no spread of the signs and symptoms in space and time. The early diagnosis of both diseases is of great importance for the beginning of the right treatment. The aim of the present thesis was to evaluate whether textural features may help in discriminating MS from CM. This was achieved by designing, implementing, and evaluating a pattern recognition system on MR images employing textural features. The clinical material consisted of 29 patients all scanned with the same MR protocol. The MS group comprised of 11 patients diagnosed with clinically definite MS. On the other hand, the CM group included 18 patients with verified CM. Every patient was scanned on a MAGNETOM Sonata MR modality of 1.5 Tesla with the Fluid Attenuated Inversion Recovery (FLAIR) protocol at the 251 General Airforce Hospital. Twenty-three textural features were calculated, 4 from the image histogram, 14 from the co-occurrence matrices and 5 from the run-length matrices. The regions used included MS and CM lesions in addition to the Normal Appearing White Matter (NAWM) adjacent to each lesion. The classification methods utilized in the present thesis included a/ the Probabilistic Neural Network (PNN) classifier used to estimate the capability of textural features in discriminating MS from CM and b/ the combination of the PNN classifier, the Support Vector Machines (SVM) classifier and the k-Nearest Neighbor classifier (k-NN) evaluated each one separately and as a whole in a Multi-Classifier (MC) system. Additionally, the Least-Square Feature Transformation (LSFT) technique was applied to improve the accuracy of the classification system by clustering the textural features, for each pathology, around arbitrary pre-selected points rendering them more separable. The performance evaluation of the designed classification schemes was based on the External Cross Validation (ECV) process, which is considered indicative for the generalization of the designed classification system to ‘unseen’ cases. It was found that the textural features calculated from MS and CM lesions contain useful clinical information regarding the texture of MS and CM as depicted on MR images. The classification accuracy attained was 73% in correctly discriminating MS from CM utilizing the ECV method. In addition, the utilization of the adjacent NAWM to each lesion and the LSFT technique in the classification scheme boosted the classification accuracy by 10% resulting in 83% overall classification accuracy in the MC system. The textural features that participated in the optimum feature vector were related to the degree of homogeneity, the amount of randomness and the dispersion of the gray-tone intensity values within the texture of the MS and CM. These textural characteristics are related to textural parameters that physicians employ in diagnosis and they were proportional to the textural imprint of MS and CM lesions i.e MS-regions were darker, of higher contrast, less homogeneous, and rougher as compared to CM. Finally, the proposed system might be of value as an assisting tool in lesion characterization when MS differential diagnosis issues arise. / Η σωστή διάγνωση της Σκλήρυνσης κατά Πλάκας (ΣκΠ) βασίζεται πρωτίστως στην αναλυτική παρατήρηση κλινικών συμπτωμάτων καθώς επίσης υποβοηθείται από την αξιολόγηση εικόνων Μαγνητικού Συντονισμού (ΜΣ) από έμπειρους ακτινολόγους. Αν και τα τυπικά απεικονιστικά χαρακτηριστικά της ΣκΠ είναι καταγεγραμμένα λεπτομερώς στην παγκόσμια ιατρική βιβλιογραφία, υπάρχουν άλλες παθολογίες του Κεντρικού Νευρικού Συστήματος των οποίων τα απεικονιστικά χαρακτηριστικά προσομοιάζουν εκείνα της ΣκΠ. Σε αυτές τις περιπτώσεις, ιδίως στην αρχική εμφάνιση της ασθένειας, προβλήματα διαφορικής διάγνωσης μπορούν να προκύψουν. Μια από τις πιο συχνά εμφανιζόμενες παθολογίες διαφορικής διάγνωσης είναι η Εγκεφαλική Μικροαγγειοπάθεια (ΕΜ). Η σωστή και έγκαιρη διάγνωση της ΣκΠ είναι πολύ σημαντική για την πορεία της ασθένειας επηρεάζοντας σαφώς και την ποιότητα ζωής του ασθενούς. Ο αυτόματος διαχωρισμός ΣκΠ από ΕΜ με την χρήση χαρακτηριστικών υφής από εικόνες ΜΣ δεν έχει εφαρμοστεί προηγουμένως. Γενικότερα η βιβλιογραφία πάνω στην διερεύνηση του προβλήματος της διαφορικής διάγνωσης της ΣκΠ από άλλες παθολογίες είναι περιορισμένη.