Bien que les résultats métaboliques de la transplantation d’îlots chez le patient diabétique de type 1 soient désormais bien démontrés, ils sont contrebalancés par les effets indésirables des traitements immunosuppresseurs et la perte de fonctionnalité du greffon à long terme.Au cours de cette thèse, nous avons étudié deux approches complémentaires offrant la perspective de s’affranchir du traitement immunosuppresseur tout en protégeant les îlots de l’apoptose et de la perte de fonctionnalité du greffon induites par les mécanismes d’isolement, de culture et de transplantation : l’immunoisolation des îlots dans des capsules de biomatériaux et la co-transplantation avec des cellules souches mésenchymateuses (CSM).Au sein du projet européen de pancréas artificiel BIOCAPAN, nous avons évalué in vitro, la biocompatibilité de différents biomatériaux et mis en évidence un effet combiné de la présence de CSM et des tripeptides RGD sur le maintien de la viabilité et de la fonctionnalité des îlots encapsulés. L’évaluation ultérieure de la biocompatibilité et de l’effet ajouté de la capsule BIOCAPAN sur des animaux diabétiques permettra la validation de la capsule qui sera proposée à des tests d’essais cliniques.Nous avons également démontré, dans un modèle de co-culture d’îlots avec des CSM dans des conditions de culture classiques et exposées à des cytokines pro-inflammatoires, que les CSM régulaient les capacités sécrétrices des îlots probablement via la régulation de l’hème oxygénase 1 (HO-1). L’identification des facteurs de transcription régulant HO-1 ainsi que des médiateurs permettant la communication entre les deux types cellulaires sont des perspectives de développement.Ce travail a souligné l’intérêt, au sein d’une approche immuno-isolante, de la reconstitution d’un environnement favorable au sein de la capsule permettant la préservation de l’îlot notamment via l’utilisation de CSM. / Although, the metabolic results of islets transplantation for patient with type 1 diabetes are now well documented, they are counteracted by the adverse effects of immunosuppressive therapies and the long-term loss in graft functionality.During this thesis, we worked on two complementary approaches offering the perspective of avoiding immunosuppressive treatment while protecting islets from apoptosis and loss of functionality induced by the mechanisms of isolation, culture and transplantation. These two tools are islet immunoisolation in capsules composed of specific biomaterials and islets co-transplantation with mesenchymal stem cells (MSCs) described for their immunomodulatory, proangiogenic and cytoprotective properties.In the european project of bioartificial pancreas BIOCAPAN, we have evaluated in vitro the biocompatibility of several biomaterials and we have highlight a combined effect of the presence of MSCs and tripeptides RGD on the viability and the functionality maintenance of the encapsulated islets. Subsequent in vivo validation of the biocompatibility and the added effect of the BIOCAPAN capsule on diabetic animals will allow the final validation of the capsule to be proposed for clinical trials.We also demonstrated, in an islet co-culture model with MSCs under conventional culture conditions and exposed to pro-inflammatory cytokines, that MSCs regulate the secretory capacity of islets probably via the regulation of heme oxygenase 1 (HO-1) described for its antioxidant and anti-inflammatory properties. The identification of transcription factors regulating HO-1 as well as mediators, allowing communication between the two cell types, are development perspectives.This work underlined the interest, within an immuno-isolation approach, of the reconstitution of a favorable environment within the capsule allowing the preservation of islet physiology thanks to the use of MSCs.

Title: Mountain tourism for diabetics with an insulin pump Objectives: The aim of this study is to find out whether it is suitable for patients with type 1 diabetes mellitus treated with an insulin pump to undergo physical activity in the form of mountain tourism, as the more intense physical aktivity affects blood glucose levels and whether patients are able to work with advanced insulin pump functions. Methods: The work is conceived as an observational study of the Medtronic educational project. One day mountain hike trip of a distance about 30 km was attended by 40 patients (men and women) with diabetes aged 15-25 years. Non-invasive methods were used. The data was obtained by monitoring insulin pump probes, glucometers and continuous monitoring, which were further evaluated using the CareLink Pro software. Results: Physical activity in the form of mountain tourism is suitable for patients with DM1 treated on an insulin pump. 80% of the probands did not have a risk status of hypoglycaemia, and even though the determined normoglycemia for research was performed by a larger number of adults as opposed to children, this FA has a demonstrable effect on blood glucose levels. It also brings positive benefits for patients because they learn how to work better with advanced insulin pump functions....

The effect of serum 25-hydroxycholekalciferol levels on musculoskeletal system in children with inflammatory bowel disease Background: Low bone mineral density and osteoporosis represent severe secondary complications that can be a result of childhood chronic disease. According to Frost's mechanostat theory impaired muscle functions may contribute to the changes observed on the skeleton. Aims: The aim of this study was to: 1) evaluate parameters of bone mineral density, bone geometry and dynamic muscle functions in children and adolescent with chronic disease - inflammatory bowel disease (IBD) and type 1 diabetes (T1D); 2) evaluate a possible effect of vitamin D deficiency and vitamin D supplementation or duration of the disease on the musculoskeletal unit; 3) determine clinical or laboratory predictors of muscle and bone parameters. Methods: The study was divided into two substudies according to the diagnosis. Seventy patients with IBD (median age 13.8 years) were included in one study, fifty-five of which completed all of the planned procedures. During the study, IBD patients were supplemented with 2000 IU/d of vitamin D. In the second study 95 patients with T1D were included (median age 16.4 years). BMD and bone geometry of non-dominant tibia was evaluated using peripheral quantitative computed...

Aims: The Childhood Diabetes Registry in Saxony, Germany, examined the incidence and metabolic characteristics of childhood diabetes. Methods: In the federal state of Saxony, newly diagnosed cases of diabetes in children and adolescents aged less than 15 years were registered continuously from 1999 until 2008. Family history, date of diagnosis, clinical and laboratory parameters were obtained. Reported cases were ascertained by public health departments as an independent data source and verified using the capture- recapture method. Results: A total of 865 children and adolescents with newly diagnosed diabetes were registered in Saxony. About 96% of them were classified as having type 1 diabetes, 0.6% had type 2 diabetes, 2.4% had maturity-onset diabetes of the young (MODY), and 1.4% had other types of diabetes. The age-standardized incidence rate of type 1 diabetes was estimated at 17.5 per 100,000 children per year. Completeness of ascertainment as calculated by the capture-recapture method amounted to 93.6%. At the time of diagnosis, 27.1% of children with type 1 diabetes had ketoacidosis, 1.5% had a blood pH <7.0, and 1.1% were unconscious. Conclusion: The registry provided data about the incidence rates and clinical presentation of childhood diabetes in a defined German population. We observed higher incidence rates compared to previous surveys. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Type 1 diabetes (T1D) is an autoimmune disease leading to destruction of insulin-secreting pancreatic -cells. Environmental factors e.g. exposures to infections, dietary components play a substantial role in etiopathogenesis of T1D and are responsible for rapid increase of T1D incidence in past decades, preferentially in developed countries. Despite long record of T1D research no causative cure or efficient prevention exists. While gluten displays proinflammatory properties, gluten-free diet (GFD) has been documented by several studies as a strong diabetes- preventive environmental factor in spontaneous animal models of T1D, mostly in NOD mouse. The aim of this thesis is to better characterize effects of GFD on the immune system of NOD mouse. Using flow cytometry, we compared effects of GFD vs standard (STD) Altromin diets on NK cell subsets, Tregs, as well as other regulatory cell subsets and their cytokine profile in prediabetic SPF NOD females that were exposed to the diets since "in utero". A reference diabetes incidence in NOD females in our SPF facility kept on STD and GFD was recorded. Diabetes-preventive capacity of GFD were tested by using the NOD-SCID model of diabetes transfer, in which splenocytes from at-onset NOD females kept on GFD or STD were transferred to NOD-SCID recipients....

Bakgrund: Diabetes typ 1 är en kronisk sjukdom i barndomen som kräver intensiv daglig egenvård. Vidare kan ungdomsåren vara en utmanande period där egenvården tenderar att brista och barnsjuksköterskan i diabetesteamet utgör en nyckelroll i stödet till ungdomarna. Arbetet beskrivs som utmanande och komplext då hens arbetet innebär att ge stöd och utbilda ungdomarna eftersom kunskap och förståelse för sin sjukdom krävs för att ungdomarna ska kunna nå egenvårdskapacitet. Syfte: Belysa barnsjuksköterskors erfarenhet av att stödja ungdomar med diabetes typ 1 så att en fungerande egenvård bibehålls. Metod: Semistrukturerad intervjustudie där sju barnsjuksköterskor med minst ett års erfarenhet av att arbeta med ungdomar med diabetes typ 1 deltog. Analysmetoden var kvalitativ innehållsanalys med induktiv ansats. Resultat: Barnsjuksköterskornas erfarenhet av att stödja ungdomar med diabetes typ 1 beskrevs utmanande vilket kräver individanpassat förhållningssätt i mötet med ungdomarna såsom att kartlägga behov, relationsskapande, tillgänglighet, delaktighet, målsättning och valmöjlighet av tekniska hjälpmedel. Det framkom även att familjen och det sociala umgänget kan ha inverkan på ungdomens egenvårdsförmåga. Slutsats: Individanpassat stöd beskrevs som avgörande för att nå fram med kunskap till ungdomarna då helhetsperspektiv och se till varje unik ungdom bidrar till adekvat stöd som kan vara givande för egenvårdskapaciteten. Familjens stöd ansågs kunna bidra med ökad egenvårdskapacitet och vid bristande stöd krävs stöd från barnsjuksköterskan även till familjen. Av vikt är även att prata om det sociala umgänget då det även kan påverka ungdomarnas egenvårdskapacitet. / Background: Type 1 diabetes is a chronic childhood disease that requires intensive daily self-care.  Furthermore adolescence is seen as a challenging period where self-care tends to fail and the pediatric nurse in the diabetes team has a key role in supporting adolescents. The work is described as challenging and complex as their work involves providing support and education, because knowledge and understanding of their illness are required to reach self-care capacity. Aim: This study aimed to illuminate pediatric nurses' experiences in supporting adolescents with type 1 diabetes so effective self-care is maintained. Method: A semi-structured interview study was conducted with seven pediatric nurses with  at least one year of experience working with adolescents with type 1 diabetes. The analysis method was qualitative content analysis with an inductive approach. Result: The pediatric nurses experiences of how support can be given to adolescents with type 1 diabetes was described as challengingly, which requires an individualized approach in the meeting with the adolescents, such as mapping needs, relationship-building, accessibility, participation, goals and choice of technical aids. It also appears that family and social interaction can significantly impact adolescents' capacity for self-care. Conclusion: Individualized support was described as crucial to reaching out with knowledge to adolescents. They had a holistic perspective and looked after each unique adolescent, contributing to adequate support to reward self-care capacity. Family support was considered to contribute to increased self-care capacity, and in case of lack of support, support from the pediatric nurse was also required for the family. It was also essential to talk about social interaction as it also can affect the adolescents self-care capacity.

Microglia and brain-resident macrophages are the sentinel immune cells of the central nervous system (CNS), and are ideally situated to respond to any damage to the brain parenchyma or vasculature. Circulating leukocytes are generally excluded from the CNS environment under homeostatic conditions but can gain access to this region in diseases that disrupt immune system function and blood-brain barrier integrity. Although these diverse immune cells exhibit properties that may engender them to be well-suited to resolve microcirculatory insults, their relative contributions to the recanalization of capillary rupture in the cortex, known as cerebral microbleeds (CMBs), has yet to be described. CMBs are particularly concerning in conditions, such as diabetes mellitus (DM), in which these insults occur more frequently and potentially underlie the onset and progression of cognitive decline. Using in vivo 2-photon microscopy and confocal imaging, here I highlight the compromised repair of CMBs in a mouse model of type 1 DM and characterize the robust, heterogeneous macrophage response to these insults. Specifically, 20% of damaged capillaries were eliminated from the circulation in the diabetic cortex and chronic insulin treatment failed to prevent this microvascular loss. Administration of interferon-α or interferon-γ neutralizing antibodies to dampen inflammatory signalling, or dexamethasone to reduce global inflammation, also failed to improve repair rates of damaged microvessels in diabetic mice. In contrast, CMBs in nondiabetic mice repaired without exception. Interestingly, depletion of CNS macrophages using the colony stimulating factor-1 receptor antagonist PLX5622 resulted in microvascular elimination in nondiabetic mice. Given the robust depletion of brain macrophage populations with this treatment, at first these data suggested that these cells were necessary for microvascular repair since their elimination produced vessel loss. However, by parsing the data I identified that microvessels repaired in all cases where macrophages were not identified at the CMB; when CX3CR1+ aggregate was localized to the injury, ~20% of microvessels were eliminated. These findings show that CNS macrophages are not required for microvascular repair following CMB. Immunofluorescent co-labelling of various microglial and macrophage markers within the diabetic CMB milieu revealed a novel population of Mac2+/TMEM119- cells, distinct from homeostatic TMEM119+ microglia. These cells reliably localized to CMBs that failed to repair and rarely associated with vessels that recanalized; Mac2+/TMEM119- cells were not found within nondiabetic CMBs. Treatment of diabetic mice with clodronate liposomes (CLR) to deplete circulating phagocytic leukocytes prevented aggregation of Mac2+/TMEM119- cells to CMBs and improved capillary repair rates. The efficacy of CLR in excluding these cells from the CMB aggregate, coincident with eradication of monocytes from circulation, indicated that these cells likely arose from the periphery. In vivo 2-photon imaging revealed significant increases in lipofuscin at the site of diabetic CMBs relative to the nondiabetic context; other phagocytic markers including CD68 and TREM2 were also upregulated. Mac2+/TMEM119- cells showed elevated lipofuscin content relative to homeostatic microglia; their association with CMBs may thus signal an increase in phagocytosis that contributes to capillary pruning. Taken together, these data identify a novel Mac2+/TMEM119- macrophage associated with pathological microvascular elimination following CMB in the diabetic neocortex. These findings highlight the diversity of immune cell responses to CNS injury and provide insights into the cellular mechanisms of capillary pruning. Furthermore, these advances in our understanding of the regulation of microvascular elimination in the diabetic brain may have clinical implications for patients with DM as they provide evidence for putative adjuvant anti-inflammatory treatments, such as CLR, in mitigating cerebrovascular pathology. / Graduate / 2022-05-06

The purpose of this study was to determine if NO blood concentrations increased acutely following an 8-week course of pulsed infrared light therapy (PILT) which could be linked to an improvement in peripheral protective sensation (PPS) in patients who have profound chronic diabetic peripheral neuropathy. A total of 22 subjects with the diagnosis of type 1 (N = 2) or type 2 (N = 20) diabetes participated in the study. PILT was administered to one foot chosen at random with the other foot serving as a within-subject control (no treatment). Patients underwent 24 treatments (3 times/week, for 8 weeks) for 30 min per treatment. Venous blood samples were taken during the last 5 min of treatment from veins in the dorsum of the control and experimental feet and were later analyzed for NO concentration. Contrary to the popular supposition, PILT treatments actually resulted in a significantly (P < 0.05) decreased concentration of NO. Additionally, there were no significant differences between the treated and untreated feet. Since in individuals where PILT has significantly improved PPS, PILT did not stimulate an increased NO content in the blood, it appears that infrared light improves peripheral protective sensation in patients by a mechanism other than an increased NO production.

Pulsed infrared light therapy (PILT) has been shown to increase peripheral sensation in diabetic patients with diabetic peripheral neuropathy (DPN). However, most studies last for very short periods, with the subjects receiving only 6-20 treatments. The purpose of this study was to evaluate the effectiveness of an eight-week course of PILT in reversing long-standing, profound DPN in patients with type 1 and type 2 diabetes. Twenty-two subjects with a diagnosis of type 1 (n=2) or type 2 (n=20) diabetes participated in the study. PILT was administered to one foot chosen at random with the other foot serving as a within-subject control (no treatment). Patients underwent 24 treatments (3 times/week, for eight weeks) for 30 min per treatment. Changes in peripheral protective sensation (PPS) were measured using Semmes-Weinstein monofilaments (SWM) ranging from 3.7 to 6.48. PILT improved PPS even in patients with long-standing chronic neuropathies whose initial pre-study sensation was not measurable with a 200-g SWM. PILT significantly improves PPS. While the exact mechanism of action is not understood, infrared light may improve peripheral neuropathies by improving foot perfusion by stimulating nitric oxide production.

The increasing healthcare burden of type 1 diabetes (T1D) makes finding preventive or therapeutic strategies a global priority. This chronic disease is characterized by the autoimmune destruction of the insulin-producing β cells. This destruction leads to poorly controlled blood glucose and accompanying life threatening acute and chronic complications. The role of viral infections as initiating factors for T1D is probable, but contentious. Therefore, my goal is to better characterize the effects of viral infection on human β cells in their function of producing insulin and to define innate immune gene responses in β cells upon viral infection. These aspects were evaluated in various platforms including mice engrafted with primary human islets, cultured primary human islets, β cells derived from human stem cells, and a human β cell line. Furthermore, the contributions of cell-type specific innate immune responses are evaluated in flow cytometry-sorted primary human islet cells. Taken together, the results from these studies provide insights into the mechanisms of the loss of insulin production in β cells during virus infection, and characterize the antiviral innate immune responses that may contribute to the autoimmune destruction of these cells in T1D.