Phenotyping of obstructive airways disease

Background Asthma and Chronic Obstructive Pulmonary Disease (COPD) are heterogeneous disorders which may be made up of different sub-types, or phenotypes, of airflow obstruction with distinct clinical characteristics. To facilitate personalised treatment the different phenotypes and their response to treatment must be clearly defined and sound diagnostic rules developed. In this thesis I explore the evidence supporting candidate phenotypes and report the results of my research, known as the New Zealand Respiratory Health Survey (NZRHS). The NZRHS was designed to determine candidate phenotypes, compare these phenotypes to those previously described, characterize their response to inhaled medication, and develop a method for allocating patients to the most appropriate phenotype. Research Aims -To explore clinical phenotypes of chronic airways disease by cluster analysis. -To examine if phenotypes identified by a previous cluster analysis exist in the independent NZRHS sample. -To compare the response to a short-acting beta-agonist inhaler between phenotype groups. -To compare the response to a short-acting muscarinic antagonist inhaler between phenotype groups. -To compare the response to an inhaled corticosteroid between phenotype groups. -To generate allocation rules and determine their predictive value for the different disorders of airways disease. Conclusions This research has identified phenotypes of airways disease that differ significantly in their clinical and pathophysiological characteristics. Evidence is presented to support the existence of the asthma/COPD overlap and obesity/co-morbid phenotypes and provide data of their responsiveness to inhaled corticosteroid, beta agonist and anti-muscarinic treatments, which may guide future management of patients with these phenotypes of obstructive airways disease

Randomised controlled trial of rhinothermy for treatment of the common cold: a feasibility study

OBJECTIVE: To determine the feasibility of a randomised controlled trial (RCT) of rhinothermy for the common cold. DESIGN: Open label, randomised, controlled feasibility study. SETTING: Single-centre research institute in New Zealand recruiting participants from the community. PARTICIPANTS: 30 adult participants with symptoms of a common cold, presenting within 48 hours of the onset of symptoms. INTERVENTIONS: Participants were randomly assigned 2:1 to receive either 35 L/min of 100% humidified air at 41°C via high flow nasal cannulae, 2 hours per day for up to 5 days (rhinothermy), or vitamin C 250 mg daily for 5 days (control). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the proportion of screened candidates who were randomised. Secondary outcomes included: proportion of randomised participants who completed the study; modified Jackson scores from randomisation to 10 days after initiation of randomised regimen; time until feeling 'a lot better' compared with study entry; time until resolution of symptoms or symptom score at 10 days postrandomisation; proportion of organisms identified by PCR analysis of nasal swabs taken at baseline; the patterns of use of the rhinothermy device; estimated adherence of the control group; and rhinothermy device tolerability. RESULTS: In all 30/79 (38%, 95% CI 27% to 50%) of potential participants screened for eligibility were randomised. Rhinothermy was well tolerated, and all randomised participants completed the study (100%, 95% CI 88% to 100%). The reduction from baseline in the modified Jackson score was greater with rhinothermy compared with control at days 2, 3, 4, 5 and 6, with the maximum difference at day 4 (-6.4, 95% CI -9.4 to -3.3). The substantial clinical benefit threshold for modified Jackson score was a 5-unit change. CONCLUSIONS: This study shows that an RCT of rhinothermy compared with low-dose vitamin C in the treatment of the common cold is feasible. TRIAL REGISTRATION NUMBER: ACTRN12616000470493; Results

Accumulation of Succinyl Coenzyme A Perturbs the Methicillin-Resistant Staphylococcus aureus (MRSA) Succinylome and Is Associated with Increased Susceptibility to Beta-Lactam Antibiotics

Penicillin binding protein 2a (PBP2a)-dependent resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is regulated by the activity of the tricarboxylic acid (TCA) cycle via a poorly understood mechanism. We report that mutations in sucC and sucD, but not other TCA cycle enzymes, negatively impact β-lactam resistance without changing PBP2a expression. Increased intracellular levels of succinyl coenzyme A (succinyl-CoA) in the sucC mutant significantly perturbed lysine succinylation in the MRSA proteome. Suppressor mutations in sucA or sucB, responsible for succinyl-CoA biosynthesis, reversed sucC mutant phenotypes. The major autolysin (Atl) was the most succinylated protein in the proteome, and increased Atl succinylation in the sucC mutant was associated with loss of autolytic activity. Although PBP2a and PBP2 were also among the most succinylated proteins in the MRSA proteome, peptidoglycan architecture and cross-linking were unchanged in the sucC mutant. These data reveal that perturbation of the MRSA succinylome impacts two interconnected cell wall phenotypes, leading to repression of autolytic activity and increased susceptibility to β-lactam antibiotics. IMPORTANCE mecA-dependent methicillin resistance in MRSA is subject to regulation by numerous accessory factors involved in cell wall biosynthesis, nucleotide signaling, and central metabolism. Here, we report that mutations in the TCA cycle gene, sucC, increased susceptibility to β-lactam antibiotics and was accompanied by significant accumulation of succinyl-CoA, which in turn perturbed lysine succinylation in the proteome. Although cell wall structure and cross-linking were unchanged, significantly increased succinylation of the major autolysin Atl, which was the most succinylated protein in the proteome, was accompanied by near complete repression of autolytic activity. These findings link central metabolism and levels of succinyl-CoA to the regulation of β-lactam antibiotic resistance in MRSA through succinylome-mediated control of two interlinked cell wall phenotypes. Drug-mediated interference of the SucCD-controlled succinylome may help overcome β-lactam resistance

Randomised controlled trial of topical kanuka honey for the treatment of rosacea

OBJECTIVE: To investigate the efficacy of topical 90% medical-grade kanuka honey and 10% glycerine (Honevo) as a treatment for rosacea. DESIGN: Randomised controlled trial with blinded assessment of primary outcome variable. SETTING: Outpatient primary healthcare population from 5 New Zealand sites. PARTICIPANTS: 138 adults aged ≥16, with a diagnosis of rosacea, and a baseline blinded Investigator Global Assessment of Rosacea Severity Score (IGA-RSS) of ≥2. 69 participants were randomised to each treatment arm. 1 participant was excluded from the Honevo group, and 7 and 15 participants withdrew from the Honevo and control groups, respectively. INTERVENTIONS: Participants were randomly allocated 1:1 to Honevo or control cream (Cetomacrogol), applied twice daily for 8 weeks. MAIN OUTCOME MEASURES: The primary outcome measure was the proportion of participants who had a ≥2 improvement in the 7-point IGA-RSS at week 8 compared to baseline. Secondary outcomes included change in IGA-RSS and subject-rated visual analogue score of change in severity (VAS-CS) on a 100 mm scale (0 mm 'much worse', 100 mm 'much improved') at weeks 2 and 8. RESULTS: 24/68 (34.3%) in the Honevo group and 12/69 (17.4%) in the control group had a ≥2 improvement in IGA-RSS at week 8 compared to baseline (relative risk 2.03; 95% CI 1.11 to 3.72, p=0.020). The change in IGA-RSS for Honevo compared to control at week 2 minus baseline was -1 (Hodges-Lehman estimate, 95% CI -1 to 0, p=0.03), and at week 8 minus baseline was -1 (Hodges-Lehman estimate, 95% CI -1 to 0, p=0.005). The VAS-CS at week 2 was 9.1 (95% CI 3.5 to 14.7), p=0.002, and at week 8 was 12.3 (95% CI 5.7 to 18.9)¸ p<0.001 for Honevo compared to control. CONCLUSIONS: Honevo is an effective treatment for rosacea. TRIAL REGISTRATION NUMBER: This trial was registered in the Australian and New Zealand Clinical Trials Registry ACTRN12614000004662

An Osteoblast-Derived Proteinase Controls Tumor Cell Survival via TGF-beta Activation in the Bone Microenvironment

Breast to bone metastases frequently induce a "vicious cycle" in which osteoclast mediated bone resorption and proteolysis results in the release of bone matrix sequestered factors that drive tumor growth. While osteoclasts express numerous proteinases, analysis of human breast to bone metastases unexpectedly revealed that bone forming osteoblasts were consistently positive for the proteinase, MMP-2. Given the role of MMP-2 in extracellular matrix degradation and growth factor/cytokine processing, we tested whether osteoblast derived MMP-2 contributed to the vicious cycle of tumor progression in the bone microenvironment.To test our hypothesis, we utilized murine models of the osteolytic tumor-bone microenvironment in immunocompetent wild type and MMP-2 null mice. In longitudinal studies, we found that host MMP-2 significantly contributed to tumor progression in bone by protecting against apoptosis and promoting cancer cell survival (caspase-3; immunohistochemistry). Our data also indicate that host MMP-2 contributes to tumor induced osteolysis (μCT, histomorphometry). Further ex vivo/in vitro experiments with wild type and MMP-2 null osteoclast and osteoblast cultures identified that 1) the absence of MMP-2 did not have a deleterious effect on osteoclast function (cd11B isolation, osteoclast differentiation, transwell migration and dentin resorption assay); and 2) that osteoblast derived MMP-2 promoted tumor survival by regulating the bioavailability of TGFβ, a factor critical for cell-cell communication in the bone (ELISA, immunoblot assay, clonal and soft agar assays).Collectively, these studies identify a novel "mini-vicious cycle" between the osteoblast and metastatic cancer cells that is key for initial tumor survival in the bone microenvironment. In conclusion, the findings of our study suggest that the targeted inhibition of MMP-2 and/or TGFβ would be beneficial for the treatment of bone metastases

Phenotyping of obstructive airways disease

Background Asthma and Chronic Obstructive Pulmonary Disease (COPD) are heterogeneous disorders which may be made up of different sub-types, or phenotypes, of airflow obstruction with distinct clinical characteristics. To facilitate personalised treatment the different phenotypes and their response to treatment must be clearly defined and sound diagnostic rules developed. In this thesis I explore the evidence supporting candidate phenotypes and report the results of my research, known as the New Zealand Respiratory Health Survey (NZRHS). The NZRHS was designed to determine candidate phenotypes, compare these phenotypes to those previously described, characterize their response to inhaled medication, and develop a method for allocating patients to the most appropriate phenotype. Research Aims -To explore clinical phenotypes of chronic airways disease by cluster analysis. -To examine if phenotypes identified by a previous cluster analysis exist in the independent NZRHS sample. -To compare the response to a short-acting beta-agonist inhaler between phenotype groups. -To compare the response to a short-acting muscarinic antagonist inhaler between phenotype groups. -To compare the response to an inhaled corticosteroid between phenotype groups. -To generate allocation rules and determine their predictive value for the different disorders of airways disease. Conclusions This research has identified phenotypes of airways disease that differ significantly in their clinical and pathophysiological characteristics. Evidence is presented to support the existence of the asthma/COPD overlap and obesity/co-morbid phenotypes and provide data of their responsiveness to inhaled corticosteroid, beta agonist and anti-muscarinic treatments, which may guide future management of patients with these phenotypes of obstructive airways disease