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    Non-invasive assessment of airway inflammation in asthma : a thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Public Health, Massey University, Wellington, New Zealand
    (Massey University, 2013) Brooks, Collin Richard
    Inflammation is a central feature in current definitions of asthma. Despite this, airway inflammation remains infrequently assessed in either population-based studies or clinical practice. In this thesis, conventional and novel non-invasive methods (based on exhaled nitric oxide (FENO) measurement and sputum induction) were used to assess airway inflammation and examine the presence, characteristics and stability of inflammatory asthma phenotypes in a general population sample, which included very young and very old individuals. It was shown that FENO measurement could be easily and cost-effectively conducted, and that flow cytometric analysis of sputum leukocyte populations is a feasible alternative to conventional manual cell counts. In particular, flow cytometric analysis was shown to be well suited to the detection of rare cell populations, and provided data suggesting that airway invariant natural killer T cells may not be a key player in asthma pathophysiology and that basophils may be a useful indicator of allergic airway inflammation in asthma. When examining inflammatory asthma phenotypes, it was shown that less than 50% of asthmatics (both children and adults) had evidence of eosinophilic inflammation, although in one small study, altered treatment resulted in phenotype changes in more than 50% of asthmatics studied. Neutrophilic airway inflammation was rare, and was statistically significantly associated with age. Approximately half of all the asthmatics studied had no detectable evidence of airway inflammation at the time of assessment. In conclusion, the methods developed and validated for the non-invasive assessment of airway inflammation allow more detailed investigations of asthma aetiology in populationbased studies. However, a single assessment of airway inflammation may not be adequate for valid identification of inflammatory asthma phenotypes. The results of the studies described in this thesis suggest that 50% of asthmatics may have eosinophilic airway inflammation, with the remainder having no airway inflammation. Further investigations of noninflammatory mechanisms are therefore warranted, as a better understanding of the mechanisms and the associated environmental exposures involved may guide the development of more effective therapies and control measures for this common phenotype.
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    An analysis of polyphenolic blackcurrant (Ribes nigrum) extracts for the potential to modulate allergic airway inflammation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2009) Taylor, Janet Lynley
    The allergic disease of asthma is characterized by an infiltration of inflammatory cells to the lung, a process co-ordinated by T-helper (TH) cells. The TH2 cytokine Interleukin (IL)-4 promotes infiltration of eosinophils to sites of inflammation. Eosinophil-selective chemoattractant cytokines (eg. eotaxins) are synthesized by lung epithelial cells. Eotaxin-3 is expressed at high levels in the asthmatic lung, predominantly after IL-4 stimulation. Eotaxin-3 is therefore a marker of inappropriate airway inflammation. Polyphenolic (PP) compounds found in high concentrations in berries may have beneficial effects in inflammatory conditions. Plant and Food Research produced high-PP extracts of blackcurrant (BC) cultivars that were tested for inflammation modulating effects. Since high doses of PPs have been shown to cause cell death, we tested two BC cultivars at a range of concentrations in a cell viability (WST-1) assay. While no toxic effects were attributable to the BC extracts (1-50µg/ml), a dose-related trend in cell death was observed and therefore 10µg/ml was chosen for further experiments Ten BC cultivars were compared for efficacy by measuring eotaxin-3 production in IL-4 stimulated human lung epithelial (A549) cells in vitro. Cells were incubated with BC extracts (10µg/ml) and IL-4 (10ng/ml) for 24 hours. The supernatants were then quantified for eotaxin-3 levels by an enzyme-linked immunosorbent assay (ELISA). All ten BC extracts reduced eotaxin-3 levels after stimulation with IL-4, and six BC extracts were effective by statistically significant levels (P<0.05), (BC cultivars -01, -02, -03, -05, -09 & -10). Of those, BC extracts of four cultivars demonstrated a reduction of more than 65% from the IL-4 stimulated control. In addition, a positive trend in inflammation modulation vs. one anthocyanin (ACN) in the BC extracts was shown. This study has demonstrated the beneficial inflammation modulatory effects of polyphenolic BC extracts, which could be related to cyanidin 3-O-rutinoside content. These results may have therapeutic potential for asthma.