In the adult central nervous system (CNS) several factors are implicated in the failure of neurons to regenerate after spinal cord injury (SCI). However, this reduced ability of injured CNS neurons to regenerate can be improved by under certain conditions. For instance, in adult dorsal root ganglion (DRG) neurons, injury to its peripheral branch (unilateral conditioning lesion) prior to injury of its central DRG branch (dorsal column cut) enhances the intrinsic capability of some but not all CNS afferent neurons to regenerate. The exact mechanism mediating this type of response is not known. However, previous studies by other groups have proposed that the regeneration of these CNS afferent neurons might be associated with the inflammatory response following injury to the peripheral DRG branch. Our general aim, was to examine the involvement of the immune response in the regeneration of the CNS DRG branch, as part of the pre-conditioned lesion model. To test this, three questions/hypotheses were investigated. Firstly, we investigated the effects of vaccination in pre-conditioned lesion animals using a peripheral nerve homogenate (PNH, sciatic nerve) as the immunogen. Given the regenerative capabilities of peripheral nerves, we proposed that exposure to this homogenate could enhance the limited regeneration of CNS fibres, after pre-conditioning of DRG neurons. Our results showed that in adult and/or neonatal Sprague Dawley (SD) rats PNH-vaccinated, had greater number of regenerated fibres, as compared to injury matched saline-vaccinated controls. Conversely, passive exposure to PNH through parental vaccination resulted in the suppression of this regenerative trigger. This suppressed competence of CNS fibres to regenerate was indirectly correlated with a reduced number of macrophage cells throughout the SCI epicentre, as compared to greater macrophage numbers found in the adult and/or neonatal treated groups. Secondly, we explored the possibility that a systemic inflammatory effect originating from the peripheral conditioning lesion, might be able to contribute to the regeneration of other injured neurons within the matured CNS. Again, using adult SD rats, we pre-conditioned the peripheral DRG branch as previous and changed the location of the CNS injury from the spinal cord to the optic nerve. Where alike any other injured neuron within the CNS, fails to regenerate. Unfortunately, our results from anterograde or retrograde labelling did not find any regenerated optic nerve fibres, although, we did find macrophage numbers to be higher in pre-conditioned lesion animals as compared to sham-operated animals. Therefore, it is possible that the pre-conditioning peripheral lesion might be allowing for a greater macrophage infiltration into the CNS compartment. Finally, we determined whether an early macrophage infiltration into the CNS compartment could be correlated with the observed CNS regeneration, characteristic of the pre-conditioned lesion model. To test this, we temporarily depleted macrophages before, during and after peripheral nerve lesion, via liposomal clodronate delivery. Our results from anterograde and retrograde labelling of spinal cord fibres revealed no regenerated CNS fibres in macrophage depleted animals, only in injury matched controls. In conclusion, macrophage cells play a beneficial role in the regeneration of CNS afferent fibres of pre-conditioned lesion DRG neurons. This most likely occurs through activation of intrinsic somatic DRG responses, as well as, an increased macrophage activation. We believe this inflammatory response to be of favourable phenotypic characteristic to the regeneration of injured CNS neurons, especially those in proximity to the DRG cell body. In addition, we propose that the conditioning peripheral lesion permits an influx of macrophage cells into the CNS compartment before injury of the CNS DRG branch, which is also likely to be supporting regeneration of afferent fibres. Future studies should evaluate the possibility that activated inflammatory cells might be infiltrating into the CNS under minimal blood-brain barrier disruption. It is clear that a complex communication between the nervous and immune system is occurring after the initial peripheral injury.

Research Doctorate - Doctor of Philosophy (PhD) / Airway inflammation is a key feature of asthma. Currently, airway inflammation can be detected through both invasive and non- invasive methods. Non invasive methods are safe, feasible and a potentially useful way to assess airway inflammatory markers in both healthy children and children with asthma. In this thesis, a variety of non-invasive markers (induced sputum, exhaled nitric oxide, and exhaled breath condensate) was used to investigate childhood asthma. The aim of the first study was to compare and contrast the different airway markers between healthy children and children with asthma. The second study described the different airway inflammatory phenotypes in children with asthma, and examined clinical predictors of these phenotypes; whereas the third study investigated the effects of environmental tobacco smoke (ETS) exposure on airway inflammation in childhood asthma. The final study assessed the knowledge and attitudes of parents of children with asthma towards passive smoking. The studies used both cross- sectional and longitudinal designs. Children with stable asthma aged between 7 - 17 years underwent clinical assessment, spirometry, exhaled nitric oxide (FeNO), exhaled breath condensate and sputum induction. Urinary cotinine was assayed to assess tobacco smoke exposure. These studies have found that children with asthma show differences in both clinical pattern and pathological pattern compared to healthy children. These differences were apparent with elevated FeNO and sputum eosinophils. In children with asthma, there was heterogeneity of airway inflammation. There were 2 stable inflammatory patterns: eosinophilic asthma and paucigranulocytic asthma. Unlike adult asthma, these phenotypes have different clinical features, which may facilitate detection of the phenotypes in clinical practice. ETS exposure in children with asthma was common and associated with a non- eosinophilic pattern of airway inflammation. In children who had a change in ETS exposure, sputum eosinophils were decreased whereas sputum neutrophils were increased during ETS exposure compared to a non- ETS exposure period. Fractional exhaled nitric oxide levels were decreased after exposure to ETS compared to those at the time of non- ETS exposure. The severity of asthma was increased in children living with parents who smoked. As a result, parents of children with asthma, especially smoking parents should be more aware about the harmful effects of smoking on their children’s health and themselves. Health risk awareness about tobacco smoke helps parental smokers alter their smoking behavior as well as protecting children from ETS exposure. In conclusion, the important findings of this thesis are the description of the inflammatory phenotypes in childhood asthma, the identification of clinical predictors of these phenotypes and the determination of the effects of ETS exposure on airway inflammatory patterns in childhood asthma. These results should facilitate understanding and management of childhood asthma and prompt treatment studies based on markers of airway inflammation.

Chaperonin 10 (Cpn10) is a mitochondrial protein with protein folding function. There is substantial evidence that extracellular Cpn10 regulates the immune response. Prior research has shown that Cpn10 binds to T cells, inhibits LPS-induced RAW264.7 macrophage cell- and healthy donor peripheral blood mononuclear cell (PBMC)-activation, and downregulates lipopolysaccharide (LPS)-induced membrane distribution of the MHC II molecule on dendritic cells (DC). Recent Phase IIa rheumatoid arthritis (RA), psoriasis and multiple sclerosis (MS) clinical trials demonstrate improved disease amelioration with Cpn10. Despite compelling evidence of the anti-inflammatory properties of Cpn10, the precise mechanisms of action are unknown. The principal aim was to characterise the modulation of inflammation by Cpn10 and in the process create a bioassay that would allow for the reliable assessment of batch-to-batch variability of Cpn10 preparations. For this purpose, a Cpn10 bioassay was performed in the RAW264.7 cell line and expanded to DC and T cell lines. Furthermore, the analysis of gene expression in healthy donor PBMC was performed, as a mixed cell population experiment, to reflect possible involvement of cell-to-cell communication pathways. Initial data showed that Cpn10 reduced LPS-induced tumour necrosis factor ?? (TNF??) expression in RAW264.7 cells. However, the Cpn10 preparation was shown to contain trace lipid contaminants, which induced cellular tolerance, resulting in the observed reduction in TNF??. Experiments with a second batch of Cpn10 showed no reduction of LPS-induced TNF?? in the RAW264.7 cells, seen with the primary batch of Cpn10 and previously reported characterisation of Cpn10. The Cpn10 bioassay conducted in DC and T cell lines was shown to have the potential to decrease toll-like receptor 9 (TLR9) expression, suggesting that Cpn10 may attenuate immune responses by downregulating receptor recognition of bacterial components. The Cpn10 bioassay conducted in LPS-stimulated PBMCs revealed that Cpn10 downregulates gene expression of Th1 related genes including the polarising cytokines IL-7, IL-12B and IL-23A and Th2 related genes including the transcriptions factors GATA3, GFI1 and CEBPB. The downregulation of these genes may play an immuno-modulatory role, having improved efficacy of Cpn10 in T cell mediated autoimmune diseases, with possible therapeutic implications in Th2 mediated diseases such as asthma. The research carried out in this thesis provides insight into the success of Cpn10 in the RA, MS and psoriasis clinical trials. These results have also supported previously published data and provide additional insight into the mechanism of action of Cpn10. In addition, a Cpn10 bioassay has been established using healthy donor PBMCs stimulated with LPS and results show a reduced expression of Th1 and Th2 associated genes. The findings that in mixed cell populations, Cpn10 downregulates not only genes involved in Th1 polarisation mainly at the signal 3 level, but is also capable of downregulating Th2 polarising genes at the signal 1 level of TCR mediated transcription factors, are of particular interest. Ultimately, research from this project has confirmed the anti-inflammatory action of Cpn10 and given useful insight into how Cpn10 acts to modulate the inflammatory response.

No description available.

Thèse (M.Sc.)--Université Laval, 2007. / Bibliogr.: f. [67ı-73. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.

Thesis (M.D.)--University of Adelaide, Dept. of Medicine and Pathology, 1985. / Includes bibliographical references (leaves 161-204).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 76-85).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 4 uppsatser.