The purpose of this study was to examine the relationship between family functioning, health-related quality of life, and metabolic control in order to identify areas for intervention that can improve medical and psychosocial outcomes for children and adolescents with type 1 diabetes. Children (N = 45) ages 8-17, both male and female, with type 1 diabetes, along with one caregiver (parent or legal guardian) (N = 45) were asked to complete the Pediatric Quality of Life Inventory (PedsQL) generic and diabetes-specific form to assess health-related quality of life along with the Diabetes Family Behavior Checklist and the Family Relationship Index of the Family Environment Scale to assess family functioning. Recent Hemoglobin A1c (A1c) was obtained from the physician at their visit or by parent report to assess metabolic control. Results indicated a significant relationship with poorer metabolic control relating to poorer physical health-related quality of life, as reported by children. All reports indicated a significant correlation between metabolic control and both general and diabetes specific health-related quality of life. There was a significant relationship with mother’s educational level on the outcome variables; educational level was therefore used as a control variable in all regression analyses. Child-reported general family functioning accounted for a significant amount of variance in child reported general health-related quality of life. Parent score on the non-supportive scale for diabetes specific family functioning accounted for a significant amount of variance in parent reported general health-related quality of life and diabetes specific health-related quality of life for their child. Results demonstrated the importance of obtaining both child and parent perspectives on issues regarding general family functioning and health-related quality of life and diabetes specific family functioning and health-related quality of life. In addition, they illustrated the importance of assessing health-related quality of life for children with diabetes as opposed to merely looking at the physical effects.

Thèse doctorat : Médecine. Virologie : Université de Nantes : 2005. / Bibliogr. 145-175 f. [587 réf.].

Thèse d'exercice : Médecine : Nancy 1 : 2009. / Titre provenant de l'écran-titre.

Objective: The purpose of this study was to highlight parent distress in diabetes, identify factors associated with distress and to show how public health and clinical professionals can assist parents in coping with their child's diabetes and living positively as a family unit. Methods: Parents of youth with diabetes (N = 41 qualitative, N = 332 quantitative) were engaged in focus groups, interviews, and survey research to understand their needs and stressors in life with a child with diabetes. Themes were examined in the qualitative data, and correlations and a regression model were run and analyzed from the quantitative data set, made available by the Behavioral Diabetes Institute. Results: The results of the study suggested that parents who were more isolated, have tense relationships with youth, and have greater family conflict are most likely to report high levels of distress. Parents shared that they experience great fear related to life with diabetes and describe the fear as "constant" and "unrelenting." Most parents experienced frustration related to life with diabetes, yet the frustration changes with time and disease experience. Distress was more common in mothers, as well as in younger parents. Distress was also shown to correlate with duration of disease and younger parent age. Discussion: Distress is a part of life with diabetes, both for the person with diabetes and their caregivers. Parent distress is particularly challenging as it includes the delicate balance between the parent being the life support for the child with diabetes and the parent learning to let go of the same child in the maturation process. Parents face difficulties knowing how to assist their child proactively without creating a negative family dynamic. There is opportunity for health professionals to intervene in the family experience in life with diabetes. Health professionals should be aware of the kind of distress families are experiencing, the environment in which the family lives and functions, and the coping mechanisms used by each person in the family with diabetes. Understanding parenting style would be useful in identifying parents that may need extra support and education about living with and helping their child with diabetes. Shifts in the diabetes education practices around diabetes would also benefit families. More emphasis on family dynamics in clinical environments would provide greater understanding for health professionals about family functioning and diabetes distress.

Le diabète de type 1 (DT1) est une maladie auto-immune très répandue dans les pays industrialisés. Cette pathologie résulte d'un dérèglement du système immunitaire qui s'attaque aux cellules bêta du pancréas. Au laboratoire, nous utilisons la souris NOD (non obèse diabétique), une souche de souris qui développe de façon spontanée un DT1 similaire à celui retrouvé chez l’homme. Chez la souris NOD, les cellules dendritiques (DCs) sont impliquées dans le bris de la tolérance. Nous avons démontré auparavant que l'injection de GM-CSF permet de générer de cellules dendritiques semi-matures empêchant le développement du DT1 chez la souris NOD. Nous nous sommes ensuite intéressés au mécanisme d'action du GM-CSF. Nous voulions savoir si le GM-CSF affectait les cellules souches au niveau de la moelle osseuse ou s’il affectait les DCs déjà différenciées. Nous avons donc généré des DCs à partir de la moelle osseuse de souris traitées ou non au GM-CSF et nous avons démontré que le GM-CSF affectait directement les cellules souches de la moelle osseuse. Les DCs obtenues de souris traitées au GM-CSF restent dans un état semi-mature et produisent plus d'IL-10 que les DCs obtenues de souris non traitées. Par la suite, nous avons développé un modèle in vitro permettant de générer des DCs similaires à celles retrouvées chez les souris traitées au GM-CSF. Ces DCs ont été dérivées de la moelle osseuse et cultivées avec une faible concentration de GM-CSF (GM/DCs) et ensuite caractérisées comme étant des DCs tolérogènes (tDCs). Ces tDCs ont un phénotype semi-mature et produisent beaucoup de cytokines anti-inflammatoires. Nous avons ensuite étudié les mécanismes moléculaires qui permettaient d'expliquer les différences observées entre les GM/DCs et les DCs immunogènes générées en présence d'IL-4 et de GM-CSF (IL-4/DCs). Nous avons démontré que les protéines composant les complexes NF-?B sont p52/p65 chez les GM/DCs et p52/p65 et p52/RelB chez les IL-4/DCs. De plus, la sous-unité p65 est préférentiellement recrutée au niveau du promoteur de l’IL-10 chez les GM/DCs tandis qu’on la retrouve sur le promoteur de l'IL-12p35 chez les IL-4/DCs. Nous avons démontré qu’une phosphorylation soutenue de ERK1/2 est responsable de la production d'IL-10 en induisant la liaison à l’ADN du facteur de transcription AP-1. Par la suite, nous avons démontré pour la première fois que le facteur de transcription C/EBPß liait l’ADN chez les GM/DCs. L'utilisation de souris déficientes en C/EBPß nous a permis de démontrer que C/EBPß était essentiel pour la résistance à la maturation des GM/DCs. De plus, nous avons démontré que p38 est essentiel à la production d'IL-10 ainsi que pour la synThèse de C/EBPß. La liaison à l’ADN de C/EBPß est dépendante de la GSK3, une enzyme qui peut être inhibée par la PI3K. Nous avons montré que l’utilisation d'inhibiteurs contre la PI3K n'affectait pas la maturation des GM/DCs, mais qu'elle modulait leur production de cytokines. Lorsque la PI3K est inhibée, les GM/DCs produisent de l’IL-23 et de l’IL-6 en plus d'acquérir la capacité de convertir les T naïfs en Th17 . En somme, nous identifions des mécanismes moléculaires clés contrôlant les fonctions tolérogènes des DCs.

This project aims to integrate knowledge of genetic susceptibility, immune cell function, and environmental modifiers in determining risk for type 1 diabetes (T1D) in the non-obese diabetic (NOD) mouse model. Similar to human T1D, disease risk in the NOD mouse is polygenic and has been mapped to multiple Idd loci. We have fine-mapped the Idd4.1 locus and identified Nlrp1b as its candidate gene. We report an alternatively spliced isoform in the diabetes-resistant Nrlp1b allele, resulting in a truncated NLRP1b protein that is unable to activate release of IL-1β. In another aspect of this project, we have characterized the critical contribution to T1D pathogenesis by γδ T cells. We report that CD27- γδT cells infiltrate islets of pre-diabetic NOD mice. Adoptive transfer of T1D to lymphocyte-deficient NOD.SCID recipients was potentiated when CD27- γδ T cells were transferred, compared to transfer of αβ T cells alone. Antibody-mediated blockade of IL-17 prevented T1D transfer in this setting. Moreover, introgression of genetic Tcrd deficiency onto the NOD background provided robust T1D protection. Finally, we report novel relationships between the gut microbiome, host sex hormones and metabolism, and T1D pathogenesis in the NOD mouse. Using germ-free, specific pathogen free, and microbiome-transplanted NOD mice, we show that colonization by commensal microbes elevated serum testosterone and protected NOD males from T1D. Transfer of gut microbiota from adult males to immature females altered the recipients’ microbiota, resulting in elevated testosterone and metabolomic changes, reduced islet inflammation and autoantibody production, and endowed robust T1D protection. Collectively, the data presented in this thesis describe a novel genetic lesion involved in T1D risk and its immunological consequences, demonstrate a potent role for IL-17-producing γδ T cells in NOD mouse model, and uncover a novel relationship between the gut microbiome, host hormonal and metabolic phenotypes, and autoimmunity risk.

This project aims to integrate knowledge of genetic susceptibility, immune cell function, and environmental modifiers in determining risk for type 1 diabetes (T1D) in the non-obese diabetic (NOD) mouse model. Similar to human T1D, disease risk in the NOD mouse is polygenic and has been mapped to multiple Idd loci. We have fine-mapped the Idd4.1 locus and identified Nlrp1b as its candidate gene. We report an alternatively spliced isoform in the diabetes-resistant Nrlp1b allele, resulting in a truncated NLRP1b protein that is unable to activate release of IL-1β. In another aspect of this project, we have characterized the critical contribution to T1D pathogenesis by γδ T cells. We report that CD27- γδT cells infiltrate islets of pre-diabetic NOD mice. Adoptive transfer of T1D to lymphocyte-deficient NOD.SCID recipients was potentiated when CD27- γδ T cells were transferred, compared to transfer of αβ T cells alone. Antibody-mediated blockade of IL-17 prevented T1D transfer in this setting. Moreover, introgression of genetic Tcrd deficiency onto the NOD background provided robust T1D protection. Finally, we report novel relationships between the gut microbiome, host sex hormones and metabolism, and T1D pathogenesis in the NOD mouse. Using germ-free, specific pathogen free, and microbiome-transplanted NOD mice, we show that colonization by commensal microbes elevated serum testosterone and protected NOD males from T1D. Transfer of gut microbiota from adult males to immature females altered the recipients’ microbiota, resulting in elevated testosterone and metabolomic changes, reduced islet inflammation and autoantibody production, and endowed robust T1D protection. Collectively, the data presented in this thesis describe a novel genetic lesion involved in T1D risk and its immunological consequences, demonstrate a potent role for IL-17-producing γδ T cells in NOD mouse model, and uncover a novel relationship between the gut microbiome, host hormonal and metabolic phenotypes, and autoimmunity risk.

Type 1 Diabetes (T1D) is an autoimmune disease where the immune system destroys the insulin-producing beta cells within the pancreas. Due to the difficulty of obtaining relevant tissue samples from patients at risk of disease, many researchers have utilized the nonobese diabetic (NOD) mouse as a model of T1D due to their natural high susceptibility for this disease which shares many characteristics with human patients. This model has been critical for uncovering many mechanisms involved in the pathogenesis of T1D including the key roles played by autoreactive T cells in the destruction of beta cells. More recently, NOD mice have shown that self-reactive B cells act as important antigen presenting cells for activating and amplifying the T cell response against beta cells. In order to identify faulty self-tolerance mechanisms causing production and activation of B cells recognizing beta cell proteins, we have developed a transgenic mouse model whereby elevated numbers of B cells are made specific for a neo-self antigen whose expression is restricted to beta cells on the T1D-prone NOD genetic background and compared it to that of transgenic mice of the non-autoimmune prone C57BL/6 (B6) genetic background. These studies revealed that NOD and B6 B cells can both be effectively tolerized to the model beta cell-restricted antigen. However, provision of help from activated T cells readily overturned this tolerance on the NOD but not the B6 background. Prior evidence has associated Idd5 (chromosome 1) and Idd9/11 (chromosome 4) diabetes susceptibility loci in NOD mice with the development of self reactive B cells contributing to T1D. The gene encoding CTLA-4 has been identified as the major candidate susceptibility gene within Idd5, thus leading to our studies comparing B cell expression of this molecule in NOD and diabetes-resistant strains. Although almost always associated with down-modulating T cells responses, our studies and that of others confirm expression of CTLA-4 by activated B cells. We encountered B cell expression of CTLA-4 to vary from that of T cells, being expressed earlier and predominantly on the cell surface rather than within intracellular vesicles. Our studies also showed aberrant expression of different splice variants of CTLA-4 by NOD B cells compared to diabetes-resistant mice controlled by genes within and outside the Idd5 genetic locus. Hence, these studies raise the possibility that CTLA-4 may contribute to T1D through its actions on both T and B cells. Given the large nature of the Idd9/11 susceptibility locus in NOD mice and the absence of any strong candidate genes that may influence the diabetogenic capacity of B cells in this strain, we resorted to microarray technology to reveal putative genes within this genomic region with the potential to control the B cell phenotype. We focused our microarray studies on the first transitional (T1) B cell population in the spleen given that it is an important stage of tolerance to peripherally expressed self-antigens which have been found to possess various defects in NOD mice. Comparing gene expression profiles of NOD T1 B cells that expressed susceptibility or resistance alleles at the Idd9/11 locus identified 20 differentially expressed genes with the potential to contribute to development of diabetogenic B cells. Overall, data presented in this thesis provides a greater understanding of the molecular and cellular mechanisms underlying B cell contribution to T1D in NOD mice. These data are hoped to eventually lead to the development of selective strategies for removing or inhibiting only those B cells that contribute to development of T1D while ensuring that humoral immunity to foreign pathogens remains intact in human patients at risk of developing disease.

Diss. (sammanfattning) Stockholm : Univ., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.