The cystic fibrosis (CF) lung microbiome has been studied in children and adults; however, little is known about its relationship to early disease progression. To better understand the relationship ...between the lung microbiome and early respiratory disease, we characterized the lower airways microbiome using bronchoalveolar lavage (BAL) samples obtained from clinically stable CF infants and preschoolers who underwent bronchoscopy and chest computed tomography (CT). Cross-sectional samples suggested a progression of the lower airways microbiome with age, beginning with relatively sterile airways in infancy. By age two, bacterial sequences typically associated with the oral cavity dominated lower airways samples in many CF subjects. The presence of an oral-like lower airways microbiome correlated with a significant increase in bacterial density and inflammation. These early changes occurred in many patients, despite the use of antibiotic prophylaxis in our cohort during the first two years of life. The majority of CF subjects older than four harbored a pathogen dominated airway microbiome, which was associated with a further increase in inflammation and the onset of structural lung disease, despite a negligible increase in bacterial density compared to younger patients with an oral-like airway microbiome. Our findings suggest that changes within the CF lower airways microbiome occur during the first years of life and that distinct microbial signatures are associated with the progression of early CF lung disease.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cystic fibrosis is one of the most common autosomal recessive genetic diseases in Caucasian populations. Diagnosis via newborn screening and targeted nutritional and antibiotic therapy have improved ...outcomes, however respiratory failure remains the key cause of morbidity and mortality. Progressive respiratory disease in cystic fibrosis is characterised by chronic neutrophilic airway inflammation associated with structural airway damage leading to bronchiectasis and decreased lung function. Mucus obstruction is a characteristic early abnormality in the cystic fibrosis airway, associated with neutrophilic inflammation often in the absence of detectable infection. Recent studies have suggested a link between hypoxic cell death and sterile neutrophilic inflammation in cystic fibrosis and other diseases via the IL-1 signalling pathway. In this review, we consider recent evidence regarding the cellular responses to respiratory hypoxia as a potential driver of sterile neutrophilic inflammation in the lung, current knowledge on hypoxia as a pathogenic mechanism in cystic fibrosis and the potential for current and future therapies to alleviate hypoxia-driven sterile inflammation.
Modulation of airway surface liquid (ASL) pH has been proposed as a therapy for cystic fibrosis (CF). However, evidence that ASL pH is reduced in CF is limited and conflicting. The technical ...challenges associated with measuring ASL pH in vivo have precluded accurate measurements in humans. In order to address this deficiency, ASL pH was measured in vivo in children using a novel luminescent technology integrated with fibre-optic probes. Here we show that ASL pH in children with CF is similar to that of children without CF. Findings were supported by highly controlled direct pH measurements in primary human airway epithelial cell culture models, which also suggest that the potential ASL pH gradient produced by defective apical ion transport is balanced out by paracellular shunting of acid/base. Thus, reduced baseline ASL pH is unlikely to be an important pathobiological factor in early CF lung disease.
Bronchiectasis causes substantial morbidity in patients with cystic fibrosis. In this study, children were followed from diagnosis until 3 years of age. Neutrophil elastase activity in the lung at 3 ...months of age was associated with persistent bronchiectasis.
Illness and death from cystic fibrosis are due primarily to progressively destructive lung disease resulting in bronchiectasis and respiratory failure. Computed tomography (CT) can detect changes in the lungs associated with bronchiectasis
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and evidence of structural lung disease in children with cystic fibrosis as young as 10 weeks of age.
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The true prevalence of bronchiectasis among children with cystic fibrosis is unknown; however, studies conducted by the Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST CF) and the Australasian Cystic Fibrosis Bronchoalveolar Lavage study group have shown that 50 to 70% of patients have CT-defined bronchiectasis by . . .
ACE2 is the primary receptor for SARS‐CoV‐2. We demonstrate that lower airway expression of ACE2 is increased in older adults and males. Lower ACE2 expression in epithelial cells also occurs in ...people with asthma and is associated with reduced furin and increased ADAM‐17 expression. This may partly explain the relative sparing of people with asthma from severe COVID‐19.
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ABSTRACT
Background and objective
COVID‐19 is complicated by acute lung injury, and death in some individuals. It is caused by SARS‐CoV‐2 that requires the ACE2 receptor and serine proteases to enter AEC. We determined what factors are associated with ACE2 expression particularly in patients with asthma and COPD.
Methods
We obtained lower AEC from 145 people from two independent cohorts, aged 2–89 years, Newcastle (n = 115) and Perth (n = 30), Australia. The Newcastle cohort was enriched with people with asthma (n = 37) and COPD (n = 38). Gene expression for ACE2 and other genes potentially associated with SARS‐CoV‐2 cell entry was assessed by qPCR, and protein expression was confirmed with immunohistochemistry on endobronchial biopsies and cultured AEC.
Results
Increased gene expression of ACE2 was associated with older age (P = 0.03) and male sex (P = 0.03), but not with pack‐years smoked. When we compared gene expression between adults with asthma, COPD and healthy controls, mean ACE2 expression was lower in asthma patients (P = 0.01). Gene expression of furin, a protease that facilitates viral endocytosis, was also lower in patients with asthma (P = 0.02), while ADAM‐17, a disintegrin that cleaves ACE2 from the surface, was increased (P = 0.02). ACE2 protein expression was also reduced in endobronchial biopsies from asthma patients.
Conclusion
Increased ACE2 expression occurs in older people and males. Asthma patients have reduced expression. Altered ACE2 expression in the lower airway may be an important factor in virus tropism and may in part explain susceptibility factors and why asthma patients are not over‐represented in those with COVID‐19 complications.
Objectives To determine the prevalence of bronchiectasis in young children with cystic fibrosis (CF) diagnosed after newborn screening (NBS) and the relationship of bronchiectasis to pulmonary ...inflammation and infection. Study design Children were diagnosed with CF after NBS. Computed tomography and bronchoalveolar lavage were performed with anesthesia (n = 96). Scans were analyzed for the presence and extent of abnormalities. Results The prevalence of bronchiectasis was 22% and increased with age ( P = .001). Factors associated with bronchiectasis included absolute neutrophil count ( P = .03), neutrophil elastase concentration ( P = .001), and Pseudomonas aeruginosa infection ( P = .03). Conclusions Pulmonary abnormalities are common in infants and young children with CF and relate to neutrophilic inflammation and infection with P. aeruginosa . Current models of care for infants with CF fail to prevent respiratory sequelae. Bronchiectasis is a clinically relevant endpoint that could be used for intervention trials that commence soon after CF is diagnosed after NBS.
Although destructive airway disease is evident in young children with cystic fibrosis (CF), little is known about the nature of the early CF lung environment triggering the disease. To elucidate ...early CF pulmonary pathophysiology, we performed mucus, inflammation, metabolomic, and microbiome analyses on bronchoalveolar lavage fluid (BALF) from 46 preschool children with CF enrolled in the Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST CF) program and 16 non-CF disease controls. Total airway mucins were elevated in CF compared to non-CF BALF irrespective of infection, and higher densities of mucus flakes containing mucin 5B and mucin 5AC were observed in samples from CF patients. Total mucins and mucus flakes correlated with inflammation, hypoxia, and oxidative stress. Many CF BALFs appeared sterile by culture and molecular analyses, whereas other samples exhibiting bacterial taxa associated with the oral cavity. Children without computed tomography-defined structural lung disease exhibited elevated BALF mucus flakes and neutrophils, but little/no bacterial infection. Although CF mucus flakes appeared "permanent" because they did not dissolve in dilute BALF matrix, they could be solubilized by a previously unidentified reducing agent (P2062), but not
-acetylcysteine or deoxyribonuclease. These findings indicate that early CF lung disease is characterized by an increased mucus burden and inflammatory markers without infection or structural lung disease and suggest that mucolytic and anti-inflammatory agents should be explored as preventive therapy.
Chest computed tomography (CT) is the gold standard for demonstrating cystic fibrosis (CF) airway disease. However, there are no standardized outcome measures appropriate for children younger than 6 ...years.
We developed the Perth-Rotterdam Annotated Grid Morphometric Analysis for CF (PRAGMA-CF), a quantitative measure of airway disease, and compared it with the commonly used CF-CT scoring method.
CT scans from the Australian Respiratory Early Surveillance Team for CF (AREST CF) cohort in Western Australia were included. PRAGMA-CF was performed by annotating a grid overlaid on 10 axial slices for the presence of bronchiectasis, mucous plugging, or other airway abnormalities (inspiratory scans) and trapped air (expiratory scans). The separate proportions of total disease (%Dis), bronchiectasis (%Bx), and trapped air (%TA) were determined. Thirty scans were used for observer reliability, and 30 paired scans obtained at 1 and 3 years old were used for comparison with a validated standard and biologic plausibility.
Intraobserver, intraclass correlation coefficients (95% confidence interval) for %Dis, %Bx, and %TA were 0.93 (0.86-0.97), 0.93 (0.85-0.96), and 0.96 (0.91-0.98), respectively. The change in %Dis (P = 0.004) and %Bx (P = 0.001) with PRAGMA-CF was related to neutrophil elastase presence at age 3, whereas only the change in bronchiectasis score was related to neutrophil elastase (P < 0.001) with CF-CT. Sample-size calculations for various effect sizes are presented.
PRAGMA-CF is a sensitive and reproducible outcome measure for assessing the extent of lung disease in very young children with CF.
Current limitations to primary cell expansion led us to test whether airway epithelial cells derived from healthy children and those with asthma and cystic fibrosis (CF), co-cultured with an ...irradiated fibroblast feeder cell in F-medium containing 10 µM ROCK inhibitor could maintain their lineage during expansion and whether this is influenced by underlying disease status. Here, we show that conditionally reprogrammed airway epithelial cells (CRAECs) can be established from both healthy and diseased phenotypes. CRAECs can be expanded, cryopreserved and maintain phenotypes over at least 5 passages. Population doublings of CRAEC cultures were significantly greater than standard cultures, but maintained their lineage characteristics. CRAECs from all phenotypes were also capable of fully differentiating at air-liquid interface (ALI) and maintained disease specific characteristics including; defective CFTR channel function cultures and the inability to repair wounds. Our findings indicate that CRAECs derived from children maintain lineage, phenotypic and importantly disease-specific functional characteristics over a specified passage range.
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