Cystic Fibrosis-Related Gut Dysbiosis: A Systematic Review

Longer term follow-up of abdominal symptoms (CFAbd-Score) after initiation of Elexacaftor / Tezacaftor / Ivacaftor in adults with cystic fibrosis

BACKGROUND

Whether improvements in gastrointestinal (GI) symptoms observed with Elexacaftor/Tezacaftor/Ivacaftor (ETI) treatment are sustained in the longer-term requires exploration. This study investigated how GI-symptoms change with longer-term ETI use in pancreatic insufficient adults with cystic fibrosis (awCF).

METHODS

Participants completed up to three abdominal symptom questionnaires, employing the validated CFAbd-Score. Changes in total CFAbd-Score and its five domains, pain, gastroesophageal reflux-disease (GERD), disorders of bowel movement (DBM), disorders of appetite (DA) and quality of life (QOL), were analysed pre-ETI (T0) and at ≤1.5 years (T1) and 2-4 years of ETI-therapy (T2).

RESULTS

A total of 165 CFAbd-Scores from 68 participants were analysed (median age: 34 years; IQR: 28-39). Total CFAbd-Score significantly (p < 0.05) and clinically meaningfully decreased from 20.4 ± 1.6 pre-ETI (median:40 weeks pre-treatment) to 15.3 ± 1.9 and 16.8 ± 1.6 at T1 (median: 25 weeks of ETI) and T2 (median: 148 weeks of ETI), respectively. The CFAbd-Score´s domains DA and QoL only significantly decreased between T0 and T1, whereas DBM only significantly decreased after 2-4 years of ETI therapy (T2). GERD scores were significantly lower at both T1 and T2.

CONCLUSION

While GI symptoms in awCF significantly improve within the first 1.5 years of ETI-therapy, they appear to somewhat wane with longer-term use, despite GI-symptom burden still being lower compared to pre-ETI. However, we cannot differentiate whether this results from reduced adherence, a decrease in ETI effects, or long-term changes in diet, gut microbiota or symptom perception. The longer-term impact of ETI and other potential modulator therapies on GI symptoms requires ongoing monitoring.

Faecal lipid profile as a new marker of fat maldigestion, malabsorption and microbiota

BACKGROUND

Fat malabsorption in children with cystic fibrosis (CF) leads to poor nutritional status and altered colonic microbiota. This study aimed at establishing the faecal lipid profile in children with CF, and exploring associations between the faecal lipidome and microbiota.

METHODS

Cross-sectional observational study with children with CF and an age-matched control group. Faecal lipidome was analysed by UHLC-HRMS and microbiota profiling by 16S rRNA amplicon sequencing.

RESULTS

Among 234 identified lipid species, five lipidome clusters (LC) were obtained with significant differences in triacylglycerols (TG), diacylglycerols (DG), monoacylglycerols (MG) and fatty-acids (FA): LC1 subjects with good digestion and absorption: low TG and low MG and FA; LC2 good digestion and poor absorption: low TG and high MG and FA; LC3 Mild digestion and poor absorption: intermediate TG and high MG and FA; LC4 poor digestion and absorption: high TG and high MG and FA; LC5 outliers. Bacteroidota and Verrucomicrobiota decreased over LC1-LC4, while Proteobacteria increased. Nutritional status indicators were significantly higher in LC1 and decreased over LC2-LC4.

CONCLUSION

Assessing faecal lipidome may be relevant to determine how dietary lipids are digested and absorbed. This new evidence might be a method to support targeted nutritional interventions towards reverting fat maldigestion or malabsorption.

IMPACT

Lipidomic analysis enabled the identification of the lipid species related to maldigestion (triglycerides) or malabsorption (monoglycerides and fatty acids). Children with cystic fibrosis can be grouped depending on the faecal lipidome profile related to dietary fat maldigestion or malabsorption. The lipidome profile in faeces is related to the composition of microbiota and nutritional status indicators.

The Impact of Complementary Feeding on Fecal Microbiota in Exclusively Breast-Fed Infants with Cystic Fibrosis (A Descriptive Study)

BACKGROUND/OBJECTIVES

Early life gut microbiota plays a pivotal role in shaping immunity, metabolism, and overall health outcomes. This is relevant in healthy infants but may be even more crucial in infants with chronic devastating diseases, such as cystic fibrosis (CF). While the introduction of solid foods in healthy infants modifies the composition of colonic microbiota, less knowledge is available on those with CF. The aim of this descriptive observational study was to assess the composition of fecal microbiota in six exclusively breast-fed infants with CF, and then explore the changes induced upon the introduction of different foods.

METHODS

two types of fecal samples were collected from each subject: one during the exclusive-breastfeeding period, and the other after incorporating each new food in the ad libitum diet. The microbiota composition was analyzed by 16S rRNA amplicon sequencing.

RESULTS

Wide heterogenicity in the composition at the phylum level (variable proportions of Actinobacteriota, Proteobacteria, and Firmicutes, and the absence of Bacteroidota in all subjects) was found, and different enterotypes were characterized in each subject by the main presence of one genus: Bifidobacterium in Subject 1 (relative abundance of 54.4%), Klebsiella in Subject 3 (49.1%), Veillonella in Subjects 4 and 5 (32.7% and 36.9%, respectively), and Clostridium in Subject 6 (48.9%). The transition to complementary feeding induced variable changes in microbiota composition, suggesting a subject-specific response and highlighting the importance of inter-individual variation.

CONCLUSIONS

Further studies are required to identify which foods contribute to shaping colonic microbiota in the most favorable way for patients with CF using a personalized approach.

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.

Prominent role of gut dysbiosis in the pathogenesis of cystic fibrosis-related liver disease in mice

BACKGROUND & AIMS

Cystic fibrosis-related liver disease (CFLD) is a chronic cholangiopathy that increases morbidity and mortality in patients with CF. Current treatments are unsatisfactory, and incomplete understanding of CFLD pathogenesis hampers therapeutic development. We have previously shown that mouse CF cholangiocytes respond to lipopolysaccharide with excessive inflammation. Thus, we investigated the role of the gut-liver axis in the pathogenesis of CFLD.

METHODS

Wild-type (WT), whole-body Cftr knockout (CFTR-KO) and gut-corrected (CFTR-KO-GC) mice were studied. Liver changes were assessed by immunohistochemistry and single-cell transcriptomics (single-cell RNA sequencing), inflammatory mediators were analysed by proteome array, faecal microbiota by 16S ribosomal RNA sequencing and gut permeability by FITC-dextran assay.

RESULTS

The livers of CFTR-KO mice showed ductular proliferation and periportal inflammation, whereas livers of CFTR-KO-GC mice had no evident pathology. Single-cell RNA sequencing analysis of periportal cells showed increased presence of neutrophils, macrophages and T cells, and activation of pro-inflammatory and pathogen-mediated immune pathways in CFTR-KO livers, consistent with a response to gut-derived stimuli. CFTR-KO mice exhibited gut dysbiosis with enrichment of Enterobacteriaceae and Enterococcus spp., which was associated with increased intestinal permeability and mucosal inflammation, whereas gut dysbiosis and inflammation were absent in CFTR-KO-GC mice. Treatment with nonabsorbable antibiotics ameliorated intestinal permeability and liver inflammation in CFTR-KO mice. Faecal microbiota transfer from CFTR-KO to germ-free WT mice did not result in dysbiosis nor liver pathology, indicating that defective intestinal CFTR is required to maintain dysbiosis.

CONCLUSION

Defective CFTR in the gut sustains a pathogenic microbiota, creates an inflammatory milieu, and alters intestinal permeability. These changes are necessary for the development of cholangiopathy. Restoring CFTR in the intestine or modulating the microbiota could be a promising strategy to prevent or attenuate liver disease.

IMPACT AND IMPLICATIONS

Severe cystic fibrosis-related liver disease (CFLD) affects 10% of patients with cystic fibrosis (CF) and contributes to increased morbidity and mortality. Treatment options remain limited due to a lack of understanding of disease pathophysiology. The cystic fibrosis transmembrane conductance regulator (CFTR) mediates Cl- and HCO3- secretion in the biliary epithelium and its defective function is thought to cause cholestasis and excessive inflammatory responses in CF. However, our study in Cftr-knockout mice demonstrates that microbial dysbiosis, combined with increased intestinal permeability caused by defective CFTR in the intestinal mucosa, acts as a necessary co-factor for the development of CFLD-like liver pathology in mice. These findings uncover a major role for the gut microbiota in CFLD pathogenesis and call for further investigation and clinical validation to develop targeted therapeutic strategies acting on the gut-liver axis in CF.

Impact of high-dose cholecalciferol (vitamin D3) and inulin prebiotic on intestinal and airway microbiota in adults with cystic fibrosis: A 2 × 2 randomized, placebo-controlled, double-blind pilot study

Background

Cystic fibrosis (CF) is a multi-organ disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Individuals with CF often have gastrointestinal (GI) dysbiosis due to chronic inflammation and antibiotic use. Previous studies suggested a role for vitamin D in reversing the GI dysbiosis found in CF.

Objective

To explore the potential role of a combination of high-dose oral cholecalciferol (vitamin D3) and fermentable dietary fiber, inulin, to impact bacterial composition, richness, and diversity of intestinal and airway microbiota in adults with CF.

Methods

This was a 2 × 2 factorial, double-blinded, placebo-controlled, randomized, pilot clinical trial in which adults with CF received oral cholecalciferol (vitamin D3) (50,000 IU/week) and/or inulin (12 g/day) for 12 weeks. Thus, there were 4 study groups (n = 10 subjects per group); 1) placebo 2) vitamin D3 3) inulin 4) vitamin D3 plus inulin. Stool and sputum samples were collected at baseline (just before) and after the intervention and were analysed using 16S ribosomal RNA gene sequencing for gut and airway microbiota composition. Statistical analyses assessed alpha and beta diversity to evaluate microbial community changes.

Results

Of a total of 254 screened participants, 40 eligible participants were randomized to one of the 4 treatment arms. Participants receiving vitamin D3 plus inulin exhibited greater changes in microbiome indexes in both intestinal and airway relative to those in the other study groups. Specific taxonomic changes supported the potential beneficial influence of this combination to mitigate both intestinal and airway dysbiosis in adults with CF.

Conclusion

This pilot study established that the combination of oral vitamin D3 and the prebiotic inulin was well tolerated over 12 weeks in adults with CF and altered gut and airway bacterial communities. Future research appear warranted to define clinical outcomes and the role of microbiota changes therein with this approach.

Cystic fibrosis liver disease in the new era of cystic fibrosis transmembrane conductance regulator (CFTR) modulators

Cystic fibrosis liver disease (CFLD) is characterised by a wide heterogenity of manifestations and severity. It represents a major cause of morbidity in people with cystic fibrosis (PwCF), which will be of increasing relevance as survival increases in the new era of cystic fibrosis care. No medical therapy currently available has evidence to treat or prevent progression of liver disease. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators may be transformative on pulmonary, nutritional and quality of life, but direct effect on long term liver disease outcomes is not yet established. Drug-associated hepatic adverse effects may be common, and clinician familiarity with drug-monitoring recommendations is essential. Longitudinal studies are required to understand the effect of CFTR modulators on the incidence and natural history of CFLD, including with early treatment initiation, in established advanced liver disease, and post liver transplantation.

Effect of beta-glucan supplementation on cystic fibrosis colonic microbiota: an in vitro study

BACKGROUND

Children with cystic fibrosis (CF) present with gut dysbiosis, and current evidence impedes robust recommendations on the use of prebiotics. This study aimed at establishing the prebiotic potential of a commercial beta-glucan on the in vitro colonic microbiota of a child with CF compared to a healthy counterpart (H).

METHODS

A dynamic simulator of colonic fermentation (twin-SHIME® model) was set up including the simulation of the proximal (PC) and distal colon (DC) of the CF and the H subjects by colonizing the bioreactors with faecal microbiota. During two weeks the system was supplied with the beta-glucan. At baseline, during treatment and post-treatment, microbiota composition was profiled by 16 S rRNA and short-chain fatty acids (SCFA) production was determined by GS-MS.

RESULTS

At baseline, Faecalibacterium, was higher in CF' DC than in the H, along higher Acidaminococcus and less Megasphaera and Sutterella. Beta-glucan supplementation induced increased microbiota richness and diversity in both subjects during the treatment. At genus level, Pseudomonas and Veillonella decreased, while Akkermansia and Faecalibacterium increased significantly in CF.

CONCLUSION

The supplementation with beta-glucan suggests positive results on CF colonic microbiota in the in vitro context, encouraging further research in the in vivo setting.

IMPACT

Current evidence supports assessing the effect of prebiotics on modifying cystic fibrosis microbiota. The effect of beta-glucan supplementation was evaluated in a controlled dynamic in vitro colonic ecosystem. Beta-glucan supplement improved diversity in cystic fibrosis colonic microbiota. The treatment showed increased abundance of Faecalibacterium and Akkermansia in cystic fibrosis. New evidence supports the use of prebiotics in future clinical studies.

Prevalence and severity of functional urinary and anorectal disorders and their impact on quality of life in cystic fibrosis

BACKGROUND

In cystic fibrosis (CF), coughing is associated with a risk of pelvic floor dysfunction. However, data on the prevalence of symptoms (stress urinary incontinence, bladder overactivity, dysuria, and faecal incontinence) are lacking in males and females with CF. The impact of incontinence on adherence to respiratory care has not been studied.

METHODS

We conducted a multicentre study in adults with CF followed in the North-West French CF network. Urinary disorders and their severity were assessed using the Urinary Symptom Profile (USP) self-report questionnaire; the impact of urinary disorders on general quality of life was measured using the SF-Qualiveen questionnaire; faecal incontinence was assessed using the Wexner self-report questionnaire; and the CFQ-R14+ questionnaire was used to assess quality of life. A self-administered questionnaire developed for the study assessed the impact of symptoms on respiratory care.

RESULTS

Of the 178 people with CF included, 34 % reported stress urinary incontinence, with a large female predominance (63.5 % of females vs. 7.5 % of males), 65 % bladder overactivity (including 16 % urge incontinence) and 50 % faecal incontinence, also with a female predominance. Neither urinary nor faecal incontinence were related to the severity of the respiratory impairment (FEV1). Quality of life was particularly affected in women. Stress urinary Incontinence symptoms affected respiratory care in both sexes.

CONCLUSION

The prevalence of functional urinary and faecal disorders was high in adults with CF and impacted on quality of life and respiratory care. Therefore, multidisciplinary teams must have knowledge of symptoms, the diagnostic tools and management strategies to provide specific treatment.

Alterations in the fecal microbiota in patients with advanced cystic fibrosis liver disease after 6 months of elexacaftor/tezacaftor/ivacaftor

BACKGROUND

Cystic fibrosis associated liver disease (CFLD) carries a significant disease burden with no effective preventive therapies. According to the gut-liver axis hypothesis for CFLD pathogenesis, dysbiosis and increased intestinal inflammation and permeability permit pathogenic bacterial translocation into the portal circulation, leading to hepatic inflammation and fibrosis. Evaluating the effect of CFTR (cystic fibrosis transmembrane conductance regulator) modulation with elexacaftor/tezacaftor/ivacaftor (ETI) may help determine the role of CFTR in CFLD and increase understanding of CFLD pathogenesis, which is critical for developing therapies. We aimed to characterize the fecal microbiota in participants with CF with and without advanced CFLD (aCFLD) before and after ETI.

METHODS

This is an ancillary analysis of stool samples from participants ages ≥12 y/o enrolled in PROMISE (NCT04038047). Included participants had aCFLD (cirrhosis with or without portal hypertension, or non-cirrhotic portal hypertension) or CF without liver disease (CFnoLD). Fecal microbiota were defined by shotgun metagenomic sequencing at baseline and 1 and 6 months post-ETI.

RESULTS

We analyzed 93 samples from 34 participants (11 aCFLD and 23 CFnoLD). Compared to CFnoLD, aCFLD had significantly higher baseline relative abundances of potential pathogens Streptococcus salivarius and Veillonella parvula. Four of 11 aCFLD participants had an initially abnormal fecal calprotectin that normalized 6 months post-ETI, correlating with a significant decrease in S. salivarius and a trend towards decreasing V. parvula.

CONCLUSIONS

These results support an association between dysbiosis and intestinal inflammation in CFLD with improvements in both post-ETI, lending further support to the gut-liver axis in aCFLD.

The gut microbiota in adults with cystic fibrosis compared to colorectal cancer

BACKGROUND

Gut dysbiosis is implicated in colorectal cancer (CRC) pathogenesis. Cystic fibrosis (CF) is associated with both gut dysbiosis and increased CRC risk. We therefore compared the faecal microbiota from individuals with CF to CRC and screening samples. We also assessed changes in CRC-associated taxa before and after triple CF transmembrane conductance regulator (CFTR) modulator therapy.

METHODS

Bacterial DNA amplification comprising V4 16S rRNA analysis was conducted on 84 baseline and 53 matched follow-up stool samples from adults with CF. These data were compared to an existing cohort of 430 CRC and 491 control gFOBT samples from the NHS Bowel Cancer Screening Programme. Data were also compared to 26 previously identified CRC-associated taxa from a published meta-analysis.

RESULTS

Faecal CF samples had a lower alpha diversity and clustered distinctly from both CRC and control samples, with no clear clinical variables explaining the variation. Compared to controls, CF samples had an increased relative abundance in 6 of the 20 enriched CRC-associated taxa and depletion of 2 of the 6 taxa which have been reported as reduced in CRC. Commencing triple modulator therapy had subtle influence on the relative abundance of CRC-associated microbiota (n = 23 paired CF samples).

CONCLUSIONS

CF stool samples were clearly dysbiotic, clustering distinctly from both CRC and control samples. Several bacterial shifts in CF samples resembled those observed in CRC. Studies assessing the impact of dietary or other interventions and the longer-term use of CFTR modulators on reducing this potentially pro-oncogenic milieu are needed.

Enterobacteriaceae in the Human Gut: Dynamics and Ecological Roles in Health and Disease

The human gut microbiota plays a crucial role in maintaining host health. Our review explores the prevalence and dynamics of Enterobacteriaceae, a bacterial family within the Proteobacteria phylum, in the human gut which represents a small fraction of the gut microbiota in healthy conditions. Even though their roles are not yet fully understood, Enterobacteriaceae and especially Escherichia coli (E. coli) play a part in creating an anaerobic environment, producing vitamins and protecting against pathogenic infections. The composition and residency of E. coli strains in the gut fluctuate among individuals and is influenced by many factors such as geography, diet and health. Dysbiosis, characterized by alterations in the microbial composition of the gut microbiota, is associated with various diseases, including obesity, inflammatory bowel diseases and metabolic disorders. A consistent pattern in dysbiosis is the expansion of Proteobacteria, particularly Enterobacteriaceae, which has been proposed as a potential marker for intestinal and extra-intestinal inflammatory diseases. Here we develop the potential mechanisms contributing to Enterobacteriaceae proliferation during dysbiosis, including changes in oxygen levels, alterations in mucosal substrates and dietary factors. Better knowledge of these mechanisms is important for developing strategies to restore a balanced gut microbiota and reduce the negative consequences of the Enterobacteriaceae bloom.

Association between Dietary Intake and Faecal Microbiota in Children with Cystic Fibrosis

A "high-fat, high-energy diet" is commonly recommended for children with cystic fibrosis (CF), leading to negative consequences on dietary patterns that could contribute to altered colonic microbiota. The aim of this study was to assess dietary intake and to identify possible associations with the composition of faecal microbiota in a cohort of children with CF. A cross-sectional observational study was conducted, including a 3-day food record simultaneously with the collection of faecal samples. The results showed a high fat intake (43.9% of total energy intake) and a mean dietary fibre intake of 10.6 g/day. The faecal microbiota was characterised at the phylum level as 54.5% Firmicutes and revealed an altered proportion between Proteobacteria (32%) and Bacteroidota (2.2%). Significant associations were found, including a negative association between protein, meat, and fish intake and Bifidobacterium, a positive association between lipids and Escherichia/Shigella and Streptococcus, a negative association between carbohydrates and Veillonella and Klebsiella, and a positive association between total dietary fibre and Bacteroides and Roseburia. The results reveal that a "high-fat, high-energy" diet does not satisfy dietary fibre intake from healthy food sources in children with CF. Further interventional studies are encouraged to explore the potential of shifting to a high-fibre or standard healthy diet to improve colonic microbiota.

Neuropsychiatric adverse effects from CFTR modulators deserve a serious research effort

PURPOSE OF REVIEW

This review highlights the problem of neuropsychiatric adverse effects (AEs) associated with elexacaftor/tezacaftor/ivacaftor (ETI), current suboptimal mitigation approaches, a novel testable mechanistic hypothesis, and potential solutions requiring further research.

RECENT FINDINGS

Studies show that a minority of persons with cystic fibrosis (PwCF) initiating cystic fibrosis transmembrane conductance regulator (CFTR) modulators experience neuropsychiatric AEs including worsening mood, cognition, anxiety, sleep, and suicidality. The GABA-A receptor is a ligand-gated chloride channel, and magnetic resonance spectroscopy neuroimaging studies have shown that reduced GABA expression in rostral anterior cingulate cortex is associated with anxiety and depression. Recent research details the impact of peripheral inflammation and the gut-brain axis on central neuroinflammation. Plasma ETI concentrations and sweat chloride have been evaluated in small studies of neuropsychiatric AEs but not validated to guide dose titration or correlated with pharmacogenomic variants or safety/efficacy.

SUMMARY

Although ETI is well tolerated by most PwCF, some experience debilitating neuropsychiatric AEs. In some cases, these AEs may be driven by modulation of CFTR and chloride transport within the brain. Understanding biological mechanisms is a critical next step in identifying which PwCF are likely to experience AEs, and in developing evidence-based strategies to mitigate them, while retaining modulator efficacy.

Dynamics of abdominal symptoms during the start of a new therapy with elexacaftor/tezacaftor/ivacaftor using the novel CFAbd-day2day questionnaire

Background: Elexacaftor-tezacaftor-ivacaftor (ETI) is a novel, highly effective CFTR modulator combination proven to enhance lung function and body weight in people with cystic fibrosis (pwCF) carrying a F508del mutation. Recently, we revealed significant reductions in abdominal symptoms (AS) in German, British, and Irish pwCF after 24-26 weeks of ETI using the CFAbd-Score, the first patient-reported outcome measure (PROM) specifically developed and validated for pwCF following FDA guidelines. Notably, many pwCF reported marked changes in their AS during the first days of the new treatment. To capture these immediate effects, we developed the CFAbd-day2day, a CF-specific GI-diary, following FDA and COSMIN guidelines. Aim: To prospectively capture the immediate dynamics of AS using the CFAbd-day2day 14 days before and 14-28 days after ETI initiation. In addition, we aim to provide validation steps of the novel PROM concerning sensitivity to changes. Methods: To develop the CFAbd-day2day, focus groups (community voice = pwCF and their proxies and CF specialists from different fields) were repeatedly consulted. Before and during the new ETI therapy, pwCF prospectively scored AS on a daily basis with the CFAbd-day2day. Results: Altogether, 45 pwCF attended in five CF centers prospectively completed the CFAbd-day2day before (mean ± sd:14 ± 7 days) and after (mean ± sd: 28 ± 23 days) ETI initiation. On the one hand, cumulative scores significantly decreased during the 3-4-week time frame after ETI initiation, compared to 2 weeks prior to therapy. On the other hand, many patients who revealed a relatively stable level of AS before ETI reported changes during the first days of treatment with the highly effective CFTR modulators. Factors like pain and flatulence increased in up to 21% of patients during the first 14 days of therapy, but they improved during days 15-27. Conclusion: The CFAbd-day2day, specifically developed and in the process of validation to prospectively capture GI symptoms in pwCF, provides new substantial insights into the dynamics of AS in pwCF receiving a new treatment with ETI. This novel tool is also helpful in prospectively monitoring patients with specific GI problems. International implementation and further validation steps of the diary are ongoing.

Effect of Lactobacillaceae Probiotics on Colonic Microbiota and Metabolite Production in Cystic Fibrosis: A Comparative In Vitro Study

Cystic Fibrosis-related gut dysbiosis (CFRGD) has become a recognised complication in children with this condition, and current evidence remains insufficient to guide the selection of probiotic strains for supplementation treatments. The aim of this study was to characterise the effect of three probiotic strains on CFRGD by means of a dynamic in vitro simulation of the colonic fermentation (SHIME®). The configuration of the system included three bioreactors colonised with the faecal inoculum of a child with cystic fibrosis. For 20 days, each bioreactor was supplied daily with either Lacticaseibacillus rhamnosus GG (ATCC 53103 TM), Limosilactobacillus reuteri (DSM 17938) or Lactiplantibacillus plantarum (DSM 22266). The baseline microbiota was characterised by a high abundance of Prevotella, Faecalibacterium and Acidaminococcus genera. After 20 days of supplementation, L. rhamnosus and L. plantarum reduced Prevotella significantly, and the three strains led to increased Faecalibacterium and Bifidobacterium and decreased Acidaminococcus, with some of these changes being maintained 10 days after ceasing supplementation. The metabolic activity remained unaltered in terms of short-chain fatty acids, but branched-chain fatty acids showed a significant decrease, especially with L. plantarum. Additionally, ammonia decreased at 20 days of supplementation, and lactate continuously increased with the three strains. The effects on colonic microbiota of L. rhamnosus, L. reuteri or L. plantarum were established, including increased beneficial bacteria, such as Faecalibacterium, and beneficial metabolites such as lactate; and on the other hand, a reduction in pathogenic genera, including Prevotella or Acidaminococcus and branched-chain fatty acids, overall supported their use as probiotics in the context of CFRGD.

Thinking outside the box: a review of gastrointestinal symptoms and complications in cystic fibrosis

INTRODUCTION

Gastrointestinal (GI)-related symptoms, complications, and comorbidities in cystic fibrosis (CF) are common and research to reduce their burden is a priority for the CF community. To enable future research, this review aimed to summarize the range of GI symptoms, complications and comorbidities seen in CF, the underlying pathophysiology, and treatments.

AREAS COVERED

This was a rapid systematic review undertaken using the recommendations from the Cochrane Rapid Reviews Methods Group. We searched databases including PubMed, Embase, Medline and the Cochrane database and identified those studies reporting GI-related symptoms, complications, or comorbidities in CF or their treatment. Our searches identified 2,930 studies and a total 119 studies met our inclusion criteria. Where a prevalence could be determined, GI symptoms were reported in 33.7% of study participants. The range of symptoms reported was broad and the highest median prevalence included flatulence (43.5%), bloating and abdominal distension (36%), and fatty stool (36%). Meconium ileus was reported in 12% and distal intestinal obstruction syndrome in 8.5.

EXPERT OPINION

GI-related symptoms, complications, and comorbidities in CF are common. More consistent characterization and recording of these symptoms in clinical studies may help achieve the priority of reducing the burden of GI disease in CF.