A longitudinal study assessing the impact of elexacaftor/tezacaftor/ivacaftor on gut transit and function in people with cystic fibrosis using magnetic resonance imaging (MRI).

BACKGROUND: Gastrointestinal (GI) symptoms in cystic fibrosis (CF) are common and disruptive. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on the GI tract is not fully understood. The aim was to use magnetic resonance imaging (MRI) to determine if elexacaftor/tezacaftor/ivacaftor (ETI) changed GI function and transit. METHODS: This was an 18 month prospective, longitudinal, observational study. We enrolled 24 people with CF aged 12 years or older to undergo MRI scans before starting ETI and 3, 6, and 18 months after starting ETI. The primary outcome measure was change in oro-caecal transit time (OCTT) at 6 and 18 months. Secondary outcome measures included change in small bowel water content (SBWC), change in the reduction in small bowel water content following a meal (DeltaSBWC) and change in total colonic volume (TCV). RESULTS: A total of 21 participants completed MRI scans at 6 months and 11 completed at 18 months. After 18 months of ETI, median OCTT significantly reduced, from >360 min [IQR 240->360] to 240 min [IQR 180-300] (p = 0.02, Wilcoxon signed-rank). Both SBWC and DeltaSBWC increased after starting ETI. TCV reduced significantly after 18 months (p = 0.005, Friedman). CONCLUSIONS: Our findings suggest an improvement in small bowel transit, small bowel response to food and a reduction in colonic volume after starting ETI. These effects may relate to CFTR activation in the small bowel. To our knowledge this is the first study to show a physiological change in GI transit and function in response to CFTR modulator use through imaging studies.

Retrospective review of treatment outcomes and costs in children with sleep disordered breathing assessed with multi-channel studies.

Current UK guidance on OSA management recommends only selective use of sleep studies - when there is diagnostic uncertainty, in children with comorbidities or to evaluate perioperative risk in those with suspected severe OSA. Routine use of sleep studies to confirm a diagnosis of obstructive sleep apnoea (OSA) in children before adenotonsillectomy is not currently recommended. We report the findings of a novel paediatric sleep service based on routine use of multi-channel sleep studies (MCSS) before adenotonsillectomy and present the results of a service evaluation assessing the impact of our practise on treatment outcomes and cost. We conducted a retrospective study of 264 children with sleep disordered breathing seen in our centre between July 2018-June 2019, using medical records and a sleep study database to determine treatment outcomes and costs. Using responses from a questionnaire completed by otolaryngologists for a separate prospective study, we compare our costs with estimates of those associated with a standard UK model of care i.e. with selective use of sleep studies. We estimate that our routine use of MCSS reduced the number of adenotonsillectomies by 44 % but at higher monetary costs than those estimated for the standard model of care. We note however, that reconfiguring our service to arrange a sleep study before the initial appointment, rather than after, would result in the service being cost neutral compared with the standard model. We also estimate that use of home multi-channel studies in our service would bring a significant cost saving (∼£50,000 - £80,000 per annum) compared to standard care.

Impact of extended Elexacaftor/Tezacaftor/Ivacaftor therapy on the gut microbiome in cystic fibrosis.

BACKGROUND: There 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 DESIGN: Faecal 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. RESULTS: Extended 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. CONCLUSIONS: Whilst differences persisted, a positive trajectory towards the microbiota observed in healthy controls was found. 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.

Prospective evaluation of the impact of multi-channel studies on treatment outcomes in children with sleep disordered breathing.

There are significant variations in practice regarding the use of sleep studies in children with symptoms of sleep disordered breathing (SDB) prior to adenotonsillectomy. Current UK guidance recommends the selective use of sleep studies to confirm a diagnosis of obstructive sleep apnoea (OSA) when there is diagnostic uncertainty, in children with comorbidities, or to assess perioperative risk when severe OSA is suspected. We have developed a novel paediatric sleep service over the past decade based on the routine use of multi-channel sleep studies (MCSS) before adenotonsillectomy. We present the results of a prospective evaluation assessing the impact of our service on treatment outcomes. We conducted a prospective service evaluation of 49 children with SDB seen between July 2021 and August 2022. We used medical records and a sleep study database to determine treatment outcomes. Otolaryngologists completed a questionnaire before each multi-channel sleep study to help evaluate the impact of sleep study findings on surgical decision making. Questionnaire responses before MCSS showed that clinicians thought 66 % of children were 'likely', 'very likely' or 'definitely' would require surgery but only 54 % of children underwent surgery following their sleep study. We estimate that the use of MCSS was associated with a 21 % reduction in children undergoing surgery in this small sample. We conclude that our use of MCSS facilitates conservative management, allowing a significant reduction in the number of children with SDB undergoing surgery, but further validation of MCSS against polysomnography is required.

Tezacaftor/Ivacaftor therapy has negligible effects on the cystic fibrosis gut microbiome.

People with cystic fibrosis (pwCF) experience a range of persistent gastrointestinal symptoms throughout life. There is evidence indicating interaction between the microbiota and gut pathophysiology in CF. However, there is a paucity of knowledge on the potential effects of CF transmembrane conductance regulator (CFTR) modulator therapies on the gut microbiome. In a pilot study, we investigated the impact of Tezacaftor/Ivacaftor dual combination CFTR modulator therapy on the gut microbiota and metabolomic functioning in pwCF. Fecal samples from 12 pwCF taken at baseline and following placebo or Tezacaftor/Ivacaftor administration were subjected to microbiota sequencing and to targeted metabolomics to assess the short-chain fatty acid (SCFA) composition. Ten healthy matched controls were included as a comparison. Inflammatory calprotectin levels and patient symptoms were also investigated. No significant differences were observed in overall gut microbiota characteristics between any of the study stages, extended also across intestinal inflammation, gut symptoms, and SCFA-targeted metabolomics. However, microbiota and SCFA metabolomic compositions, in pwCF, were significantly different from controls in all study treatment stages. CFTR modulator therapy with Tezacaftor/Ivacaftor had negligible effects on both the gut microbiota and SCFA composition across the course of the study and did not alter toward compositions observed in healthy controls. Future longitudinal CFTR modulator studies will investigate more effective CFTR modulators and should use prolonged sampling periods, to determine whether longer-term changes occur in the CF gut microbiome. IMPORTANCE People with cystic fibrosis (pwCF) experience persistent gastrointestinal (GI) symptoms throughout life. The research question "how can we relieve gastrointestinal symptoms, such as stomach pain, bloating, and nausea?" remains a top priority for clinical research in CF. While CF transmembrane conductance regulator (CFTR) modulator therapies are understood to correct underlying issues of CF disease and increasing the numbers of pwCF are now receiving some form of CFTR modulator treatment. It is not known how these therapies affect the gut microbiome or GI system. In this pilot study, we investigated, for the first time, effects of the dual combination CFTR modulator medicine, Tezacaftor/Ivacaftor. We found it had negligible effects on patient GI symptoms, intestinal inflammation, or gut microbiome composition and functioning. Our findings are important as they fill important knowledge gaps on the relative effectiveness of these widely used treatments. We are now investigating triple combination CFTR modulators with prolonged sampling periods.

A randomised crossover trial of tezacaftor-ivacaftor for gut dysfunction in cystic fibrosis with magnetic resonance imaging (MRI) outcomes: a pilot study.

Background: People with cystic fibrosis (CF) can experience recurrent chest infections, pancreatic exocrine insufficiency and gastrointestinal symptoms. New cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs improve lung function but gastrointestinal effects are unclear. We aimed to see if a CFTR modulator (tezacaftor-ivacaftor,TEZ/IVA) improves gastrointestinal outcomes in CF. Methods: We conducted a randomised, double-blind, placebo-controlled, two-period crossover trial (2019-2020) at Nottingham University Hospitals. The effects of TEZ/IVA on gut physiology were measured using MRI. Participants were randomly assigned to treatment sequences AB or BA (A:TEZ/IVA, B:placebo, each 28 days), with a 28-day washout period. Participants had serial MRI scans at baseline and after 19-23 days of each treatment. Due to the COVID-19 pandemic, a protocol amendment allowed for observer-blind comparisons prior to and during TEZ/IVA. In such cases, participants were not blind to the treatment but researchers remained blind. The primary outcome was oro-caecal transit time (OCTT). Secondary outcomes included MRI metrics, symptoms and stool biomarkers. Results: We randomised 13 participants. Before the COVID-19 pandemic 8 participants completed the full protocol and 1 dropped out. The remaining 4 participants followed the amended protocol. There were no significant differences between placebo and TEZ/IVA for OCTT (TEZ/IVA >360minutes [225,>360] vs. placebo 330minutes [285,>360], p=0.8) or secondary outcomes. There were no adverse events. Conclusions: Our data contribute to a research gap in the extra-pulmonary effects of CFTR modulators. We found no effect after TEZ/IVA on MRI metrics of gut function, GI symptoms or stool calprotectin. Effects might be detectable with larger studies, longer treatment or more effective CFTR modulators. ClinicalTrialsgov registration: NCT04006873 (02/07/2019).

Magnetic resonance imaging of the gastrointestinal tract shows reduced small bowel motility and altered chyme in cystic fibrosis compared to controls.

People with cystic fibrosis (CF) experience digestive symptoms but the mechanisms are incompletely understood. Here we explore causes and consequences of slower gastrointestinal transit using magnetic resonance imaging (MRI). Twelve people with CF and 12 healthy controls, matched for age and gender, underwent MRI scans, both fasted and after standardised meals, over 6.5 h. Fasted small bowel motility scores were lower in CF than in controls. No difference in ascending colon chyme T1 was detected. The difference in texture between small bowel and colon contents, seen in health, was diminished in CF. The ascending colon in CF participants had an abnormal appearance compared to controls. MRI offers unique potential to evaluate gut luminal content, colonic mucosa and intestinal motor activity. These new data support the theoretical cycle of desiccation, dysmotility and delayed transit as a cause of gastrointestinal symptoms in CF.

Intestinal function and transit associate with gut microbiota dysbiosis in cystic fibrosis.

BACKGROUND: Most 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 DESIGN: Faecal 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. RESULTS: pwCF 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. CONCLUSIONS: Alterations 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.

Timing of pancreatic enzyme replacement therapy (PERT) in cystic fibrosis.

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive, life-limiting, multisystem disease affecting over 70,000 individuals worldwide. Between 80% and 90% of people with CF suffer with pancreatic exocrine insufficiency, which if left untreated, leads to a poor nutritional status. Pancreatic enzyme replacement therapy (PERT) has been shown to be effective in improving nutritional status and subsequently associated with improved lung function. However, the timings of PERT administration in relation to a meal are subjective and not standardised, meaning that variations in the timing of PERT dosing persist. OBJECTIVES: The primary objective of the review is to compare the efficacy (fat absorption) and effectiveness (nutritional status, lung function and quality of life) of different PERT dosing strategies in terms of timing of administration for treating dietary malabsorption in all individuals with CF. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of last search: 24 June 2021. We also searched ongoing trials registers on 09 July 2021. SELECTION CRITERIA: Randomised controlled trials (RCTs), including cross-over RCTs with a minimum washout period of two weeks, and quasi-RCTs of PERT dosing regimens in people (of any age) with CF. DATA COLLECTION AND ANALYSIS: Two authors independently assessed and screened the studies identified from the searches. We planned to use GRADE to assess the certainty of evidence for our pre-specified critical outcomes, but we did not identify any eligible studies. MAIN RESULTS: No studies met the eligibility criteria and therefore we did not include any in this review. The excluded studies were either cross-over in design (but lacking a sufficient washout period between treatments) or did not assess the timing of PERT. One study which was terminated early is awaiting assessment pending further information. AUTHORS' CONCLUSIONS: We were unable to determine whether one dosing schedule for PERT is better than another since we identified no eligible RCTs. While the introduction of PERT to people with CF can improve their nutritional status, there are a limited number of studies which address this review question, and none met our eligibility criteria. Since malnutrition and adverse gastrointestinal symptoms remain a common feature in CF, the assessment of the relative performance of dosing schedules may provide evidence to improve outcomes in people with CF who are pancreatic insufficient. Further research is needed to fully evaluate the role of dosing schedules for PERT in fat absorption. Research should also establish reliable outcome measures and minimal clinically important differences. While RCTs with a cross-over design may have advantages over a parallel group design, an adequate washout period between intervention periods is essential.

Postprandial changes in gastrointestinal function and transit in cystic fibrosis assessed by Magnetic Resonance Imaging.

BACKGROUND: Cystic fibrosis (CF) is a multi-system genetic disorder affecting >72,000 people worldwide. Most CF patients experience gastrointestinal symptoms and can develop complications. However, the mechanisms of CF gut disease are not well understood. We evaluated gut function and transit in CF using magnetic resonance imaging (MRI). We hypothesised oro-caecal transit time (OCTT) is longer in CF; with lower small bowel water content (SBWC). METHODS: Twelve CF patients aged 12-40 years and 12 age and sex-matched controls underwent serial MRIs over 1 day with standardised meals. The primary endpoint was OCTT, assessed by the appearance of a food bolus in the caecum. Other measures included corrected SBWC and corrected colonic volume (both area under the curve, AUC), gastric half-emptying time and gastrointestinal symptoms. RESULTS: OCTT was longer in CF (CF 330 mins [270, >360] vs. controls 210 mins [173, 315], p = 0.04), with no difference in gastric half-emptying times. Corrected SBWC was higher in CF (CF 62 L.min/m2 [36, 80] vs. controls 34 L.min/m2 [28, 41], p = 0.021); minimal postprandial decrease between T240 and T300 (CF 13 mL/m2 [-13, 57] vs. controls 102 mL/m2 [67, 108], p = 0.002) suggests impaired ileal emptying. Corrected colonic volumes were higher in CF (CF 186 L.min/m2 [167, 206] vs. controls 123 L.min/m2 [89, 146], p = 0.012). There were no differences in gastrointestinal symptoms. CONCLUSIONS: MRI provides novel insights into CF pathophysiology. Sub-clinical ileal obstruction may be more prevalent than previously thought. Gastrointestinal MRI shows promise as an investigational tool in CF.

How can we relieve gastrointestinal symptoms in people with cystic fibrosis? An international qualitative survey.

INTRODUCTION: Relieving gastrointestinal (GI) symptoms was identified as a 'top ten' priority by our James Lind Alliance Priority Setting Partnership in cystic fibrosis (CF). We conducted an online survey to find out more about the effect of GI symptoms in CF. METHODS: We co-produced an online survey distributed to the CF community via web-based platforms. The survey consisted of open and closed questions designed to help us learn more about the effects of GI symptoms for people with CF (pwCF). We analysed the data using descriptive statistics and thematic analysis. We promoted the survey via social media and web-based platforms which allowed respondents from any country to take part. Our participants came from the CF community, including: adults and children with CF, parents and close family of pwCF and healthcare professionals (HCPs) working with pwCF. RESULTS: There were 276 respondents: 90 (33%) pwCF, 79 (29%) family, 107 (39%) HCPs. The most commonly reported symptoms by lay respondents were stomach cramps/pain, bloating and a 'combination of symptoms'. The top three symptoms that HCPs said were reported to them were reduced appetite, bloating and constipation. Almost all (94% (85/90)) HCPs thought medications helped to relieve GI symptoms but only 58% (82/141) of lay respondents agreed. CONCLUSIONS: Our survey has shown that GI symptoms among our participants are prevalent and intrude on daily lives of pwCF. There is a need for well-designed clinical studies to provide better evidence for management of GI symptoms and complications.

Treatment of pulmonary exacerbations in cystic fibrosis.

PURPOSE OF REVIEW: This review will discuss the challenges of defining a pulmonary exacerbations in cystic fibrosis and the key pathogens, which contribute. It will discuss the treatment options currently available and the importance of preventing pulmonary exacerbations. RECENT FINDINGS: The basis for treatment of pulmonary exacerbations remains unchanged over the past 15 years and whilst there have been trials exploring alternative antibiotics, there has been little change. However, there are ongoing studies that are expected to establish a platform for identifying best practices. Chronic cystic fibrosis therapies have been shown to reduce pulmonary exacerbations. In the era of new CFTR (cystic fibrosis transmembrane conductance regulator) modulator therapies, the number of pulmonary exacerbations are expected to be even fewer. However, it is unclear whether the other chronic therapies can be discontinued without losing their benefits in reducing exacerbations. SUMMARY: Although there is no universal definition of a pulmonary exacerbation in cystic fibrosis, proposed definitions have many similarities. We have outlined the current recommendations for treatment of pulmonary exacerbations, including the duration and location of treatments. We have also summarized the key therapies used for prevention of pulmonary exacerbations in cystic fibrosis.

Conservative management of antenatally diagnosed cystic lung malformations.

AIM: To review the outcome of all antenatally diagnosed conservatively managed congenital lung malformations (CLMs) managed at our centre. METHODS: All patients diagnosed antenatally with cystic lung malformations from 2001 to 2011, at a tertiary referral paediatric surgical centre practising a policy of conservative management of asymptomatic cases, were retrospectively reviewed. Data were collected from medical case notes and radiology reports. Ethical approval was obtained from our institutional research and development department. RESULTS: The complete records of 74 fetuses antenatally diagnosed with CLM were reviewed. There were 72 live births, at a median gestation of 39.6 weeks. Emergency lobectomy was performed in one symptomatic neonate. Elective lobectomies were performed at parental request in three asymptomatic infants, one of whom had a family history of synovial sarcoma. Two patients developed pneumonia in the affected lobe during early childhood and proceeded to lobectomy at the age of 3 years. One patient with a bronchopulmonary sequestration required embolisation for cyanotic episodes. The remaining 65 patients have been conservatively managed to date, and none have required hospital admission. Less than a quarter report mild respiratory symptoms such as cough or wheeze. Median follow-up is 5 years. CONCLUSIONS: This retrospective cohort study of 74 consecutive CLMs diagnosed antenatally over a 10-year period demonstrates that most of these lesions will remain asymptomatic throughout childhood. Although the natural history of CLMs in later years remains to be elucidated, we hope that this report on medium-term outcomes will be useful to clinicians who undertake antenatal counselling and may inform the discussion on how best to manage these children.