Journal of Cystic Fibrosis

BackgroundMost people with cystic fibrosis (pwCF) suffer from gastrointestinal symptoms and are at risk of gut complications. Gut microbiota dysbiosis is apparent within the CF population across all age groups, with evidence linking dysbiosis to intestinal inflammation and other markers of health. This pilot study aimed to investigate the potential relationships between the gut microbiota and gastrointestinal physiology, transit, and health. Study DesignFaecal samples from 10 pwCF and matched controls were subject to 16S rRNA sequencing. Results were combined with clinical metadata and MRI metrics of gut function to investigate relationships. ResultspwCF had significantly reduced microbiota diversity compared to controls. Microbiota compositions were significantly different, suggesting remodelling of core and rarer satellite taxa in CF. Dissimilarity between groups was driven by a variety of taxa, including Escherichia coli, Bacteroides spp., Clostridium spp., and Faecalibacterium prausnitzii. The core taxa were explained primarily by CF disease, whilst the satellite taxa were associated with pulmonary antibiotic usage, CF disease, and gut function metrics. Species-specific ordination biplots revealed relationships between taxa and the clinical or MRI-based variables observed. ConclusionsAlterations in gut function and transit resultant of CF disease are associated with the gut microbiota composition, notably the satellite taxa. Delayed transit in the small intestine might allow for the expansion of satellite taxa resulting in potential downstream consequences for core community function in the colon. HighlightsO_LIFaecal microbiota significantly differs between pwCF and healthy controls C_LIO_LIKey SCFA producers contributed to microbiota dissimilarity between groups C_LIO_LIPulmonary antibiotic treatment heavily impacted gut microbiota C_LIO_LIIntestinal physiology and transit impacted satellite microbiota composition C_LI

BackgroundPatients with cystic fibrosis (CF) are characterised by abnormalities of the intestinal tract relating to gut motility and physiological issues, with daily symptoms of disease including abdominal pain, flatulence, bloating, and constipation. With improvements in respiratory outcomes, a shift in disease manifestations has highlighted the prevalence of the gastrointestinal-related problems associated with CF, yet most therapies currently in clinical use for the gut symptoms of CF have been repurposed from other disease indications and have not been developed with a knowledge of the mechanisms underpinning gastrointestinal disease in CF. Increased attention towards the role of intestinal inflammation and microbial dysbiosis in the CF population warrants a comprehensive knowledge of these aspects alongside the increased luminal fat content, dysmotility, and small intestinal bacterial overgrowth (SIBO) resultant of the primary consequences of CFTR dysfunction (disrupted fluid secretion and pancreatic insufficiency), and how they contribute towards the intestinal complications of CF disease. Methods and Study DesignWe will conduct a systematic review to comprehensively address our current understanding of the primary consequences of CFTR dysfunction, and their subsequent secondary effects that contribute towards the disruption of gut motility, health, and associated symptoms in the CF intestine. Databases searched will include PubMed, CINAHL, MEDLINE and the Cochrane library from 1939 until a specified date of last search, alongside clinical trial databases for ongoing studies. Search strategies will include various terminology that relates to the primary mechanistic defects of CF, postulated secondary effects of such defects, and symptoms experienced in patients. A full search strategy is outlined in appendix B. One reviewer will apply an inclusion criterion to obtained abstracts. Following agreement from a second reviewer, full-text articles will be sought, and data will be extracted from relevant articles. Disagreements will be resolved with a third reviewer. The quality of data will be assessed by the GRADE criteria. Data will be used to present a narrative, and where possible, quantitative synthesis. DiscussionThis systematic review will discuss our current understanding of the underpinning mechanisms of the persisting abnormalities in gut health and motility within CF, addressing potential intricate relationships that further contribute to disease progression within the intestinal tract. Furthermore, we will identify current gaps in the literature to propose directions for future research. A comprehensive understanding of these aspects in relation to intestinal abnormalities will aid future clinical directions.

Background and aimsGastrointestinal symptoms remain common in adults with cystic fibrosis (CF) despite cystic fibrosis transmembrane conductance regulator modulator use, suggesting persistent and heterogeneous gut dysfunction. This prospective observational study tests the hypothesis that distinct gut symptom phenotypes in CF can be observed and linked to underlying mechanisms. MethodsAdults from three UK CF centres completed the Gastrointestinal Symptom Rating Scale, Patient Assessment of Constipation Symptoms and a bowel-habit questionnaire. Latent class analysis using an ordinal logistic model was applied to 36 symptom indicators. Associations between phenotypes and demographic, clinical, and treatment variables were examined using generalised linear models. ResultsThree hundred participants completed questionnaires (54% male; median 31 years). We identified four symptom phenotypes: mild; moderate-constipation predominant; moderate-diarrhoea predominant and severe. The severe phenotype was associated with gastroesophageal reflux (RRR 2.86; 95%CI: 1.30-6.31; p=0.009), distal intestinal obstruction syndrome (RRR 2.46; 95%CI: 1.04-5.81; p=0.04), proton pump inhibitor (RRR 3.29; 95%CI 1.39-7.74; p=0.007), and laxative use (RRR 6.13; 95%CI 2.54-14.84; p<0.001). CF-related liver disease was associated with both moderate-constipation and diarrhoea phenotypes, respectively (RRR 2.08; 95%CI 1.13-3.81; p=0.018; RRR 2.11; 95%CI 1.03-4.29; p=0.04). There was a lower likelihood of long-term oral antibiotic use in the moderate-constipation phenotype (RRR 0.53; 95%CI 0.3-0.92; p=0.025) and moderate-diarrhoea phenotype (RRR 0.46; 95%CI 0.24-0.91; p=0.025). ConclusionsFour distinct symptom phenotypes were identified, independent of demographics and pancreatic status, but associated with specific complications and medication profiles. These phenotypes provide a framework for mechanistic studies within the GRAMPUS-CF cohort and precision management of CF-related gut disease.

Background and AimsCystic fibrosis (CF) is a multi-system genetic disorder affecting >72,000 people worldwide. Most people with CF experience gastrointestinal symptoms and some will develop complications such as distal intestinal obstruction syndrome. However the mechanisms of symptoms and complications are not understood. We evaluated gut function and transit of CF using magnetic resonance imaging (MRI). Our hypotheses were: oro-caecal transit time (OCTT) is longer in CF, with lower small bowel water content (SBWC). MethodsTwelve people with CF at a tertiary centre and 12 age and sex-matched controls underwent serial MRIs over 1 day, with meals at set times. The primary endpoint was OCTT, assessed by the appearance of a food bolus in the caecum. Other measures included SBWC, colonic volume, gastric half-emptying time and gastrointestinal symptoms. ResultsOCTT was longer in CF (controls 210 minutes [173, 315] vs. CF 330 minutes [270, >360], p=0.04). There was no difference in gastric half-emptying times (controls 80 minutes [66, 88] vs. CF 97 [71, 128], p=0.3). Corrected SBWC was higher in CF (controls 34 L.min/m2 [28, 41] vs. CF 63 L.min/m2 [36, 80], p=0.021), with minimal second post-prandial decrease suggesting impaired ileal emptying. Corrected colonic volumes were higher in CF (controls 123 L.min/m2 [89, 146] vs. CF 186 L.min/m2 [166, 209], p=0.012). There were no differences in gastrointestinal symptoms. ConclusionsSignificant differences in gut function and transit exist between CF and controls. Our methodology provides a platform for studying gastrointestinal function in CF and has identified new potential mechanisms of dysfunction. ClinicalTrials.gov NCT03566550

BackgroundThere is a paucity of knowledge on the longer-term effects of CF transmembrane conductance regulator (CFTR) modulator therapies upon the gut microbiome and associated outcomes. In a pilot study, we investigated longitudinal Elexacaftor/Tezacaftor/Ivacaftor (ETI) therapy on the gut microbiota, metabolomic functioning, and clinical outcomes in people with CF (pwCF). Study designFaecal samples from 20 pwCF were acquired before and then following 3, 6, and 17+ months of ETI therapy. Samples were subjected to microbiota sequencing and targeted metabolomics to profile and quantify short-chain fatty acid composition. Ten healthy matched controls were included for comparison. Clinical data, including markers of intestinal function were integrated to investigate relationships. ResultsExtended ETI therapy increased core microbiota diversity and composition, which translated to gradual shifts in whole microbiota composition towards that observed in healthy controls. Despite becoming more similar over time, CF microbiota and functional metabolite compositions remained significantly different to healthy controls. Antibiotic treatment for pulmonary infection significantly explained a relatively large degree of variation within the whole microbiota and rarer satellite taxa. Clinical outcomes were not significantly different following ETI. ConclusionsA positive trajectory towards the microbiota observed in healthy controls was found. However, we posit that progression was predominately impeded by pulmonary antibiotics administration. We recommend future studies use integrated omics approaches within a combination of long-term longitudinal patient studies and model experimental systems. This will deepen our understanding of the impacts of CFTR modulator therapy and respiratory antibiotic interventions upon the gut microbiome and gastrointestinal pathophysiology in CF.

BackgroundCystic fibrosis (CF) research has increasingly focused on understanding the extra-pulmonary manifestations of CF, including on the gastrointestinal (GI) system. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies outside the lungs is also a topic of research interest and both are key research priorities. However, significant evidence gaps persist in understanding the complex pathophysiology of CFTR dysfunction in the GI tract, and the treatment of these GI problems. Inconsistencies in outcome reporting may contribute towards these evidence gaps, and a standardised approach to outcome reporting may help to address this. This systematic rapid review aims to identify and catalogue the range of outcome measurement instruments (OMIs) and associated endpoints currently used in CF GI research. MethodsThis PROSPERO-registered review (CRD42021281961) was conducted following Cochrane Rapid Reviews Methods Group and COMET initiative guidance. Comprehensive searches were performed in MEDLINE, EMBASE, PubMed, Cochrane Library, and ongoing clinical trials databases, covering an 11-year period (August 2013 to November 2024). Screening and data extraction were carried out using Covidence online software. ResultsA total of 1,541 studies were identified, of which 193 met inclusion criteria. These studies collectively used 246 distinct OMIs, of which 172 (70%) were employed in only one study. The OMIs identified were grouped into 14 sub-domains representing key areas of GI research in CF, which were subsequently mapped to 11 of the 38 outcome domains in the taxonomy proposed by the COMET Initiative. The identified outcomes spanned a diverse range of mechanistic and patient-centred measures, reflecting the complexity of GI disease in CF. ConclusionsCurrent research into the GI tract in CF uses a heterogeneous array of OMIs, with limited standardisation. This highlights both the complexity of CFTR dysfunction within the GI tract, requiring a wide scope of OMIs to address this, as well the variability and potential inefficiency in current outcome reporting practices. To advance our understanding of CF pathophysiology in the GI tract, a standardised approach to outcome reporting is needed. Our findings support the development of a core outcome set to promote reporting consistency and improve comparability across studies in CF GI research.

BackgroundCystic fibrosis (CF) has profoundly changed since the introduction of CF Transmembrane Conductance Regulator modulator therapies (CFTRmt), a class of medications that improve function of the CFTR protein encoded by certain CF-causing gene mutations. Amongst these, the triple combination therapy elexacaftor-tezacaftor-ivacaftor (ETI) has been the most impactful and widely used to date. Given chronic respiratory infection and concomitant inflammation is the leading cause of morbidity and early mortality for the majority in CF, what is not certain are the long-term effects of ETI therapy on the respiratory microbiota and pathogens imbedded within. Here we assessed the long-term effects of ETI CFTRmt over 3-years on the respiratory microbiota of a multi-centre cohort of 276 adults with CF (awCF) from 6 CF centres in the UK, USA, and Canada, and compared to a non-CF healthy cohort. ResultsWe determined that respiratory microbiota characteristics (diversity, dominance, and composition) became decreasingly like those of awCF pre-ETI and remodelled to align more with the healthy cohort, where canonical CF pathogens increasingly became less ecologically important in terms of their distributions and abundances across awCF with increased duration on therapy. However, the on-ETI microbiota was impeded from becoming fully healthy due to continued antibiotic exposure and irreversible lung damage experienced by awCF. Specifically, we found that azithromycin, an antibiotic widely used principally for its immunomodulatory benefits, had adverse effects on the respiratory microbiota nullifying the observed positive effects of ETI treatment. When administered alongside ETI-therapy, the use of azithromycin maintained a pre-ETI microbiota dysbiosis and enabled enhanced persistence of emblematic CF pathogens. ConclusionsThe highly anticipated introduction of ETI CFTRmt has greatly changed the course of CF for many people living with this inherited disease. Here we find that ETI CFTRmt enabled positive remodelling of the respiratory microbiota towards a healthy-like state. However, azithromycin impeded total remodelling, making it an ideal candidate for evaluation for discontinuation in the CFTRmt era. While traditional pathogens become less ecologically important the potential evolution and emergence of virulent strains should be investigated. Additionally, the impacts and implications of ETI therapy on the understudied fungal microbiota should also be explored.

BackgroundWe recently demonstrated that the triple combination CFTR modulator therapy elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves lung ventilation and airway mucus plugging determined by multiple-breath washout and magnetic resonance imaging in CF patients with at least one F508del allele. However, effects of ELX/TEZ/IVA on viscoelastic properties of airway mucus, chronic airway infection and inflammation have not been studied. The aim of this study was, therefore, to determine the effects of ELX/TEZ/IVA on airway mucus rheology, microbiome and inflammation in CF patients with one or two F508del alleles aged 12 years and older. MethodsIn this prospective observational study, we assessed sputum rheology, the microbiome, inflammation markers and proteome before and 8 to 16 weeks after initiation of ELX/TEZ/IVA. ResultsIn total, 59 patients with CF and at least one F508del allele and 10 healthy controls were enrolled in this study. ELX/TEZ/IVA improved the elastic modulus (G; -6.3 Pa; IQR, -17.9 to 1.2; P<0.01) and viscous modulus (G; -1.6 Pa; IQR, -3.6 to 0.5; P<0.05) of CF sputum. Further, ELX/TEZ/IVA improved the microbiome -diversity (0.6; IQR, 0.0 to 1.2; P<0.001) and decreased the relative abundance of Pseudomonas aeruginosa in CF sputum. ELX/TEZ/IVA also reduced IL-8 (-11.7 ng/ml, IQR, -36.5 to 11.2; P<0.05) and free NE activity (-27.5 {micro}g/ml, IQR, - 64.5 to -3.5; P<0.001), and shifted the CF sputum proteome towards healthy. ConclusionsOur data demonstrate that ELX/TEZ/IVA improves sputum viscoelastic properties, chronic airway infection and inflammation in CF patients with at least one F508del allele, however, without reaching levels close to healthy. Clinical trial registered with www.clinicaltrials.gov (NCT04732910)

Cystic fibrosis (CF) is caused by defective Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. CFTR controls chloride (Cl-) and bicarbonate (HCO3-) transport into the Airway Surface Liquid (ASL).We investigated the impact of F508del-CFTR correction on HCO3- secretion by studying transepithelial HCO3- fluxes. HCO3- secretion was measured by pH-stat techniquein primary human respiratory epithelial cells from healthy subjects (WT) and people with CF (pwCF)carrying at least oneF508del variant.Its changes after CFTR modulation by the triple combination VX445/661/770 and in the context of TNF-+IL-17 induced inflammation were related to ASL pH and transcriptionnal levels of CFTRand other HCO3- transporters ofairway epithelia such asSLC26A4 (Pendrin), SLC26A9 and NBCe1. CFTR-mediated HCO3-secretion was not detected in F508del primary human respiratory epithelial cells. It was rescued up to [~] 80% of the WT levelby VX-445/661/770. In contrast,TNF-+IL-17 normalized transepithelial HCO3-transportand ASL acidic pH. This was related to anincrease in SLC26A4 and CFTR transcript levels.VX-445/661/770 induced an increase in pH only in the context of inflammation.Effects on HCO3- transport werenot differentbetween F508del homozygous and F508del heterozygous CF airway epithelia. Our studies show that correction of F508del-CFTRHCO3- is not sufficient to buffer acidic ASL and that inflammation is a key regulator of HCO3-secretion in CF airways. Prediction of the response to CFTR modulators by theratyping should take into account airway inflammation.

Patient-derived organoids hold great potential as predictive biomarker for disease expression or therapeutic response. Here, we used intestinal organoids to estimate individual cystic fibrosis transmembrane conductance regulator (CFTR) function of people with cystic fibrosis, a monogenic life-shortening disease associated with more than 2000 CFTR mutations and highly variable disease progression. In vitro CFTR function in CF intestinal organoids of 176 individuals with diverse CFTR mutations was quantified by forskolin induced swelling and was strongly associated with longitudinal changes of lung function and development of pancreatic insufficiency, CF-related liver disease and diabetes. This association was not observed when the commonly used biomarker of CFTR function sweat chloride concentration was used. The data strongly exemplifies the value of an organoid-based biomarker in a clinical disease setting and supports the prognostic value of forskolin induced swelling of intestinal organoids, especially for people with CF who have rare CFTR genotypes with unclear clinical consequences.

BackgroundSputum is the sample to monitor the lower respiratory tract microbiota in cystic fibrosis (CF), but young patients often cannot expectorate. We hypothesized that throat swabs could reflect lower airway colonization and assessed the concordance of bacterial community composition between paired sputum and throat swab samples from children with CF. MethodsThe prospective longitudinal multicenter MUCOVIB cohort included 379 samples from 61 CF children. Using V3-V4 16S rRNA amplicon metagenomics, we compared bacterial community diversity and composition between sputum and throat swabs in the full cohort and in 11 patients with paired samples from the same visit. ResultsSputum and Throat swabs exhibited similar bacterial diversity, regardless of the exacerbation status, and presented a substantial agreement for detecting pathogens (Cohens Kappa: 0.6). Differences in bacterial abundance were observed (p=0.001), but not presence/absence (p=0.098). Community typing revealed three distinct community types, with 86% of paired samples falling into the same cluster, highlighting the homogeneity between sputum and throat swabs microbiota. Network analysis demonstrated slight, non-random similarities in microbial interactions between sample types (ARI = 0.08 and 0.10). The average distance between samples collected from the same visit was shorter (0.505, {+/-} 0.056 95%CI), compared to sputum (0.695, {+/-} 0.017) or throat swab (0.704, {+/-} 0.045) from the same patient collected during different visits. ConclusionsThroat swabs can provide representative information on lower respiratory microbiota. Clinicians should collect throat swabs rather than relying on sputum samples from previous visits to guide antibiotic prescriptions in CF children unable to expectorate.

BackgroundDespite significant clinical improvements, there is evidence of persisting airway inflammation in people with cystic fibrosis established on Elexacaftor/tezacaftor/ivacaftor (ETI) therapy. As CF is a multi-system disease, systemic immune profiles can reflect local inflammation within the lungs and other organs. Understanding systemic inflammation after ETI therapy may reveal important translational insights. This study aims to profile systemic inflammatory changes and relate these to the well-documented improvements observed with ETI therapy. MethodsWe conducted a single-centre longitudinal study with 57 CF subjects initiating ETI therapy. All participants were Phe508del homozygous or Phe508del/minimal function. Blood samples were collected pre-ETI and 3-12 months post-therapy initiation. Analyses included mass spectrometry-based proteomics, a multiplex immunoassay, and flow cytometry for peripheral immune cell counts and phenotype. Controls samples were provided by 29 age-matched healthy controls. ResultsSystemic inflammation reduced with ETI therapy; however, the immune profile remained distinct from healthy controls. ETI reduced neutrophil counts and was associated with a more mature, less inflammatory phenotype, as well as a shift toward an immune resolving state associated with increased CD206 expression. Cytokines known to influence neutrophil levels reduced with therapy. Despite ETI therapy, neutrophil and monocyte counts remained elevated compared to healthy controls. There was no obvious association between the ETI-related improvements in systemic inflammation and lung function. ConclusionsPatients with CF show evidence of persisting systemic inflammation despite ETI therapy, this may have long term potentially adverse effects on respiratory and other organ systems.

Acute pulmonary Exacerbations (AE) are episodes of clinical worsening in cystic fibrosis (CF), often precipitated by infection. Timely detection is critical to minimize the morbidity and lung function decline associated with acute inflammation during AE. We previously demonstrated that the airway protein Short Palate Lung Nasal epithelium Clone 1 (SPLUNC1) is regulated by inflammatory signals. Here, we investigated the use of SPLUNC1 fluctuations to diagnose and predict AE in CF. We enrolled adult CF subjects from two independent cohorts to measure AE markers of inflammation in sputum and recorded clinical outcomes for a 1-year follow-up period. SPLUNC1 levels were high in healthy control sputum (n=9, 10.7g/mL), and significantly decreased in CF subjects without AE (n=30, 5.7g/mL, p=0.016). SPLUNC1 levels were 71.9% lower during AE (n=14, 1.6g/mL, p=0.0034) regardless of age, sex, CF-causing mutation, or microbiology findings. Cytokines Il-1{beta} and TNF were also increased in AE,whereas lung function did not consistently decrease. Stable CF subjects with lower SPLUNC1 levels were much more likely to have an AE at 60 days (Hazard Ratio: 11.49, Standard Error: 0.83, p=0.0033). Low-SPLUNC1 stable subjects remained at higher AE risk even one year after sputum collection (Hazard Ratio: 3.21, Standard Error: 0.47,p=0.0125). SPLUNC1 was transcriptionally downregulated by inflammatory cytokines and degraded by proteases increased in sputum during AE. Our findings suggest that low sputum SPLUNC1 levels could detect subjects at increased risk of AE in order to guide early therapeutic interventions in CF. TAKE-HOME MESSAGESputum concentrations of the secreted airway protein SPLUNC1 decrease during CF exacerbations. Lower SPLUNC1 levels in stable subjects portend a significantly increased risk of exacerbation and could inform therapeutic interventions. PLAIN LANGUAGE SUMMARYSPLUNC1 is an abundant host defense protein found in the respiratory tract that decreases with inflammation. Individuals with cystic fibrosis experiencing clinical worsening (exacerbation) have much lower levels of SPLUNC1 in their sputum. In stable cystic fibrosis patients, lower levels of SPLUNC1 may predict an upcoming respiratory illness. Therefore, SPLUNC1 may serve as a tool for early diagnosis and treatment of cystic fibrosis exacerbations.

BackgroundNovel small molecule therapies for cystic fibrosis (CF) are showing promising efficacy and becoming more widely available since recent FDA approval. The newest of these is a triple therapy of Elexacaftor-Tezacaftor-Ivacaftor (ETI, Trikafta(R)). Little is known about how these drugs will affect polymicrobial lung infections, which are the leading cause of morbidity and mortality among people with CF (pwCF). Methodswe analyzed the sputum microbiome and metabolome from pwCF (n=24) before and after ETI therapy using 16S rRNA gene amplicon sequencing and untargeted metabolomics. ResultsThe lung microbiome diversity, particularly its evenness, was increased (p = 0.044) and the microbiome profiles were different between individuals before and after therapy (PERMANOVA F=1.92, p=0.044). Despite these changes, the microbiomes were more similar within an individual than across the sampled population. There were no specific microbial taxa that were different in abundance before and after therapy, but collectively, the log-ratio of anaerobes to classic CF pathogens significantly decreased. The sputum metabolome also showed changes due to ETI. Beta-diversity increased after therapy (PERMANOVA F=4.22, p=0.022) and was characterized by greater variation across subjects while on treatment. This significant difference in the metabolome was driven by a decrease in peptides, amino acids, and metabolites from the kynurenine pathway. Metabolism of the three small molecules that make up ETI was extensive, including previously uncharacterized structural modifications. ConclusionsThis study shows that ETI therapy affects both the microbiome and metabolome of airway mucus. This effect was stronger on sputum biochemistry, which may reflect changing niche spaces for microbial residency in lung mucus as the drugs effects take hold, which then leads to changing microbiology. FundingThis project was funded by a National Institute of Allergy and Infectious Disease Grant R01AI145925

Chronic inflammation dominates disease pathogenesis in Cystic Fibrosis (CF) and there is a need to characterise CF immunity. Whole blood cultures offer a cost-effective and non-invasive approach to investigate immune responses within the host environment. Here we used whole blood cultures to investigate the differentiation potential of monocytes (CD45+CD14+ cells) in CF (N=10) and controls (N=8) in the presence and absence of exogenous macrophage-colony stimulatory factor (M-CSF) or granulocyte-macrophage (GM)-CSF with and without interleukin (IL)-4. In CF and control cultures, CD45+CD14+ cells upregulated HLA-DR expression in all instances, and increased CD206 in the presence of GM-CSF with and without IL-4, and CD209 in the presence of GM-CSF and IL-4. In CF, we consistently observed reduced upregulation of CD206 in response to GM-CSF and a positive correlation between CD206 expression and lung function (FEV1). This was unique to cultured monocytes, and not seen with any other marker. These results highlight the potential of whole blood cultures to reveal cellular characteristics in differentiating monocytes related to clinical parameters that could guide the identification of novel biomarkers in CF.

BackgroundElexacaftor/Tezacaftor/Ivacaftor (ETI) has significantly improved clinical outcomes for people with cystic fibrosis (pwCF), but the molecular effects on airway inflammation remains incompletely understood. This study aimed to characterise longitudinal changes in airway inflammation and sputum proteomes following ETI treatment, and to correlate proteomic shifts to changes in inflammatory cytokines. Patients and methodsSputum from pwCF (n=30) were collected before start of ETI and after 3 and 9-12 months of treatment. Sputum from healthy control subjects (n=7) were included for comparison. Samples were analysed for total proteome content using data independent acquisition liquid chromatography tandem mass spectrometry (DIA LC-MS/MS), and inflammatory cytokines using Mesoscale assays. Protein expression trends were analysed using k-means clustering, and correlations between airway proteomes and inflammatory cytokines were performed using Pearson correlation and enrichment analysis. ResultsETI therapy resulted in significant changes in the airway proteome, mainly related to decreased neutrophil degranulation and an increase in anti-proteases. Levels of IL-1{beta}, IL-8, and TNF decreased with ETI therapy, which correlated with proteins involved in neutrophil degranulation. In contrast, IL-6 levels increased and correlated with proteins involved in O-glycosylation of mucins. Despite these improvements, proteomic and cytokine profiles remained distinct from healthy controls after 9-12 months. ConclusionETI leads to broad shifts in airway protein expression in pwCF with reduced neutrophilic inflammation and restored protease/antiprotease balance. Despite these changes, there is still increased airway inflammation compared to healthy control sputum. This dataset provides a valuable resource for further exploration of CF airway biology under ETI therapy.

IntroductionElexacaftor, Tezacaftor, Ivacaftor (ETI) became available in the UK in August 2020 to treat people with Cystic Fibrosis (CF) aged > 12 years. We report a real-world study of clinical outcomes in young people treated with ETI at our CF centre within the first two years of its availability. MethodsParticipants aged 12-17 were identified within our clinic, with demographic data supplemented by the UK CF registry. Comprehensive outcome data spanning two years pre- and two years post-initiation of CFTR modulators were compiled from various local sources, including patient records, medication delivery logs, and clinical notes. ResultsOf the 62 patients started on ETI (32 male, mean age 13.3 years), most (76%) were homozygous for the F508del mutation. Three discontinuations occurred: one pregnancy, two related to side effects. Adherence was high (Proportion of Days covered >90% both years). Following ETI initiation there was a significant increase in mean FEV1% (+11.7 units; 95% CI 7.4 - 15.6), sustained throughout the two-year treatment period. There was no association between baseline lung function and the degree of improvement or rate of decline post-treatment. Improvements were similar for all treatable genotypes. There was a small increase in BMI z-score at four months of treatment, returning to baseline by 24 months. There was a marked reduction in the need for intravenous antibiotics. ConclusionsETI use in adolescents in a real-world setting led to sustained improvements in health outcomes, consistent with those seen in open trial extension studies O_LIWhat is already known on this topic - Clinical trials have demonstrated the efficacy of the highly effective CFTR modulator ETI in improving health outcomes for CF patients. However, there is a significant gap in understanding its real-world impact, particularly in young patients where adherence to optimise long-term outcomes is crucial. C_LIO_LIWhat this study adds - ETI provides sustained real-world benefits in young people with CF, including better lung function and reduced need for intravenous antibiotic treatment. High adherence likely plays a role. C_LIO_LIHow this study might affect research, practice or policy - These findings support the widespread adoption of ETI in eligible CF patients and emphasise the need for further research to assess its long-term benefits and optimal integration into CF treatment protocols. C_LI

Non-cystic fibrosis bronchiectasis (NCFB) is a disease characterized by abnormal dilatation of the airways, airflow obstruction, persistent cough, excessive sputum production and recurrent lung infections. NCFB exhibits clinical and pathological manifestations similar to key features of cystic fibrosis (CF) lung disease. In CF, pathogenesis results from dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR), and diagnosis is made by demonstrating elevated sweat chloride concentrations (typically [&ge;]60 mEq/L), two CFTR mutations known to be causal, multi-organ tissue injury, or combination(s) of these findings. Based on a considerable body of evidence, we believe many patients with NCFB have disease likely to benefit from drugs such as elexacaftor/tezacaftor/ivacaftor (ETI) that activate CFTR-dependent ion transport. ETI is currently prescribed solely for treatment of CF, and has not been adequately tested or proposed for patients with NCFB, many of whom exhibit decreased CFTR function. Accordingly, we are conducting a clinical trial of ETI in subjects carrying a diagnosis of NCFB. Participants will exhibit one disease-causing CFTR mutation and/or sweat chloride measurements of 30-59 mEq/L. Cutaneous punch biopsy or blood samples will be obtained for iPS cell differentiation into airway epithelial monolayers - which will then be tested for response to ETI. Each patient will be given CFTR modulator treatment for approximately four weeks, with monitoring of clinical endpoints that include FEV1, sweat chloride, quality of life questionnaire, and weight. The study will evaluate response of patients with NCFB to ETI, and test usefulness of iPSC-derived airway epithelial monolayers as a novel in vitro technology for predicting clinical benefit. FUNDING SOURCEMarcus Foundation, Inc "Main Study" Summary O_TBL View this table: org.highwire.dtl.DTLVardef@14e1b3corg.highwire.dtl.DTLVardef@de3e5borg.highwire.dtl.DTLVardef@d00554org.highwire.dtl.DTLVardef@10e0bc3org.highwire.dtl.DTLVardef@1264029_HPS_FORMAT_FIGEXP M_TBL C_TBL ObjectivesO_ST_ABS Lead in study: Incidence of diminished CFTR activity among patients with NCFBC_ST_ABSIn order to gain information regarding numbers of individuals with NCFB who may be eligible for our main study, patients at Emory followed with bronchiectasis (who do not have clinical criteria sufficient for a diagnosis of cystic fibrosis) will be asked to consider participating in a lead in study that will determine the subjects CFTR genotype and sweat chloride level. A separate consent form will be utilized for the lead in study. Subjects who exhibit a single CF-causing mutation in CFTR and/or sweat chloride 30-59 mEq/L will be approached about their interest in reviewing the consent form for the main study ("iPSC derivation and in vivo ETI treatment for 4 weeks"; see following section). Up to 200 subjects will be included in the lead-in study. Main study: iPSC derivation and in vivo ETI treatment for 4 weeksWe propose a clinical trial of subjects with a diagnosis of NCFB. Participants will exhibit one disease-causing CFTR mutation and/or sweat chloride measurements of 30-59 mEq/L. Each patient will be given ETI for approximately four weeks. We will monitor clinical endpoints that include FEV1, sweat chloride, quality of life questionnaire, and weight. We will also collect cutaneous punch biopsy material or blood samples from subjects so iPS cells can be differentiated into airway epithelial monolayers and tested for response to ETI.

Sweat parameters such as volume and chloride concentration may offer invaluable clinical insights for people with CF (PwCF). Pilocarpine-induced sweat collection for chloridometry measurement is the gold-standard for sweat chloride, but this technique is cumbersome and not suitable for remote settings. We have previously reported the utility of a skin-interfaced microfluidic device (CF Patch) in conjunction with a smartphone image processing platform that enables real-time measurement of sweating rates and sodium chloride loss in laboratory and remote settings. Here we conducted clinical studies characterizing the accuracy of the CF Patch compared to pilocarpine-induced sweat measurements using chloridometry and tested the feasibility of exercise-induced sweat chloride measurements in PwCF. The CF Patch demonstrated strong correlations compared to sweat chloride measured by chloridometry across clinic and remote settings and detected greater day-to-day sweat chloride variability in PwCF on CFTR modulators than healthy volunteers. These findings demonstrate that the CF Patch is suitable as a remote management device capable of measuring chloride concentrations and offers the potential of monitoring the efficacy of CF medication regimens.

Defective OprD porins contribute to carbapenem resistance and may be important in Pseudomonas aeruginosa adaptation to cystic fibrosis airways. It is unclear whether oprD mutations are fixed in populations of shared strains that are transmitted between patients or whether novel variants arise during infection. We investigated oprD sequences and antimicrobial resistance of two common Australian shared strains, constructed P. aeruginosa mutants with the most common oprD allelic variants and compared characteristics between patients with or without evidence of infection with strains harbouring these variants. Our data show that three independently acquired nonsense mutations arising from a 1-base pair substitution are fixed in strain sub-lineages. These nonsense mutations are likely to contribute to reduced carbapenem susceptibility in the sub-lineages without compromising in vitro fitness. Not only was lung function worse among patients infected with strains harbouring the nonsense mutations than those without, but they also had an increased hazard rate of lung transplantation/death. Our findings further highlight that understanding adaptive changes may help to distinguish patients with greater adverse outcomes despite infection with the same strain.