Jodie L. Simpson

Description:Objective: To examine airway inflammatory cell profiles in Indigenous Australian adults with asthma and chronic obstructive pulmonary disease (COPD). Methods: A retrospective, cross-sectional study on data from a tertiary referral respiratory outpatient clinic. Methods: Indigenous (n=23) and non-Indigenous (n=71) adults were matched according to diagnosis, gender and age to the ratio of 1:3. Methods: Participants were defined by self-determined identification as Indigenous (Aboriginal) or non-Indigenous. A relevant history was taken, and lung function was measured by spirometry. In those with a diagnosis of asthma, symptom control was assessed by the Asthma Control Questionnaire, six items (ACQ6). In those with a diagnosis of COPD, symptoms were assessed by the COPD assessment test (CAT). Airway cell counts were obtained in all groups from bronchial lavage (BL) cell count. Results: Lung function and inhaled corticosteroid dose were similar between groups. Current smoking was three times more common in Indigenous people (35%) compared with non-Indigenous people (12%, p=0.009). In participants with asthma, ACQ6 scores were similar between Indigenous and non-Indigenous participants with asthma. In those with COPD, Indigenous participants had significantly higher total CAT scores as well as scores for cough and sputum with a score indicating a high impact on quality of life (CAT score ≥14, 85%-25%, p=0.017). There was no difference in BL cell differential counts. Conclusions: Indigenous people with COPD had higher smoking rates, worsened CAT scores and more symptoms of cough and sputum production. There were no differences between the groups in airway inflammation, but neutrophilic inflammation was associated with poorly-controlled asthma.

Description:Background: Exacerbations contribute significantly to the burden of asthma. Some individuals are predisposed to recurring exacerbations; however, the underlying mechanisms are not well understood. Objective: Our aim was to generate a sputum protein signature associated with future exacerbations. Methods: A total of 22 baseline sputum samples from the control (placebo control) arm of the AMAZES study were analyzed by using an optimized high-throughput mass spectrometry method. Results: With use of a log fold change of at least 1.5 and a P value of .05 as cutoffs, univariate analysis identified 533 differentially abundant sputum proteins in participants with and without future exacerbations over the ensuing 48 weeks. A multivariate signature of 260 proteins for predicting future exacerbations was developed by using sparse partial least squares data analysis, which was partially able to predict (with an area under the receiver operating characteristic curve of 0.95 and an error rate of 0.41) those who would likely experience an exacerbation. Next, from sputum samples collected from an additional 123 participants, the 20 most influential proteins were selected for validation and quantification. After validation, 9 proteins were found to be linked to future exacerbation risk. The final model was able to predict future exacerbations with an area under the receiver operating characteristic curve of 0.77 and an error rate of 0.40. Pathway analysis revealed major themes associated with exacerbations, including inflammation, recruitment, and proliferation of immune cells. Conclusions: This study has identified, for what we believe is the first time, a sputum proteomic signature and pathways associated with future exacerbations, which will facilitate the discovery of new biomarkers and novel therapeutic targets in uncontrolled persistent asthma.

Description:Sputum extracellular DNA (eDNA) is associated with disease severity in asthma and COPD and therefore emerging as a potential therapeutic target. The aim of this study was to investigate the effect of 10 days of recombinant human DNase (rhDNase) treatment of eDNA-high asthma and COPD on sputum eDNA levels, neutrophil-related inflammation, lung function and symptoms. Adults with asthma (n=80) or COPD (n=66) were screened for the presence of high (>20 µg·mL-1) sputum eDNA and those eligible (n=18 asthma, n=17 COPD) were randomised to a two-period crossover controlled trial consisting of daily nebulised rhDNase (2.5 mg/2.5 mL) or placebo (5 mL 0.9% saline) for 10 days, with a 2-week washout period. The primary outcome was sputum eDNA, and secondary outcomes included sputum neutrophil extracellular trap (NET)-related biomarkers, inflammatory cell counts, lung function and respiratory symptoms. At screening, high eDNA was associated with significantly higher sputum total cell count, sputum colour score and inflammation (HNP1-3, LL-37 and interleukin-1β) in both asthma and COPD compared to low eDNA groups. In asthma, participants with high eDNA were older and had poorer lung function and asthma control compared to low eDNA. Administration of nebulised rhDNase significantly reduced sputum eDNA levels in both asthma (median (Q1-Q3) Pre: 48.4 (22.1-74.1); Post: 17.0 (5.0-31.0) µg·mL-1; p=0.022) and COPD (median (Q1-Q3) Pre: 39.3 (36.7-55.6); Post: 25.4 (11.3-38.6) µg·mL-1; p=0.044) compared to placebo. Symptoms, lung function and NET biomarkers remained unchanged. In asthma, there was a reduction in banded blood neutrophils (3.2 (0-7.7) to 0.0 (0.0-1.5); p=0.044). Targeted rhDNase treatment for 10 days effectively reduced sputum eDNA in eDNA-high asthma and COPD.

Description:Background: Chronic airway disease (CAD) is characterized by chronic airway inflammation and colonization of the lungs by pro-inflammatory pathogens. However, while various other bacterial species are present in the lower airways, it is not fully understood how they influence inflammation. We aimed to identify novel anti-inflammatory species present in lower airway samples of patients with CAD. Methods: Paired sputum microbiome and inflammatory marker data of adults with CAD across three separate cohorts (Australian asthma and bronchiectasis, Scottish bronchiectasis) was analyzed using Linear discriminant analysis Effect Size (LEfSE) and Spearman correlation analysis to identify species associated with a low inflammatory profile in patients. Results: We identified the genus Aggregatibacter as more abundant in patients with lower levels of airway inflammatory markers in two CAD cohorts (Australian asthma and bronchiectasis). In addition, the relative abundance of Aggregatibacter was inversely correlated with sputum IL-8 (Australian bronchiectasis) and IL-1β levels (Australian asthma and bronchiectasis). Subsequent in vitro testing, using a physiologically relevant three-dimensional lung epithelial cell model, revealed that Aggregatibacter spp. (i.e. A. actinomycetemcomitans, A. aphrophilus) and their cell-free supernatant exerted anti-inflammatory activity without influencing host cell viability. Conclusions: These findings suggest that Aggregatibacter spp. might act to reduce airway inflammation in CAD patients.

Description:Drugs that attenuate hyperactivation of the phosphatidylinositol 3-kinase-Akt and Ras-mitogen-activated protein kinase signaling pathways are emerging treatments for children with rare, intractable vascular anomalies or PIK3CA-related overgrowth spectrum (PROS) with an eligible genetic diagnosis. However, access to genetic testing remains a barrier to genetic diagnosis. Here, we implement a targeted molecular diagnostic strategy for vascular anomalies or PROS. We applied a novel genetic testing strategy to children with vascular anomalies or PROS using a tiered approach of (1) droplet digital PCR, (2) Sanger sequencing, (3) high-depth exome sequencing, and (4) reanalysis of existing clinical exome data. We applied this strategy to 60 individuals detecting pathogenic somatic variants in 33 of 60 (55%). This included 26 individuals with slow-flow lesions with variants in PIK3CA, TEK, GNAQ, GNA11, BRAF, or PIK3R1, 4 individuals with fast-flow lesions with variants in KRAS or MAP2K1, 1 individual with a PIK3CA variant and a mixed phenotype, and 2 individuals with PIK3CA variants and PROS without vascular anomalies. We demonstrate an effective genetic diagnostic strategy for children with vascular anomalies or PROS identifying somatic variants in 55% of individuals. Increasing genetic diagnostic yield extends the clinicogenetic spectrum and may provide access for those with intractable disease to therapeutic drug trials.