Impact of CFTR Modulation on Intestinal pH, Motility, and Clinical Outcomes in Patients With Cystic Fibrosis and the G551D Mutation. Clin Transl Gastroenterol. 2017;8:e81. [PMID: 28300821 PMCID: PMC5387753 DOI: 10.1038/ctg.2017.10]

Impact of highly effective modulator therapy on gastrointestinal symptoms and features in people with cystic fibrosis

Highly effective modulator therapy (HEMT), particularly the triple combination elexacaftor-tezacaftor-ivacaftor (ETI), significantly improved clinical outcomes and quality of life in people with Cystic Fibrosis (pwCF). This review analyzes current knowledge on the impact of HEMTs on gastrointestinal (GI) symptoms and features in pwCF. A descriptive review of English literature until February 29, 2024, was conducted using medical databases. Observational studies and clinical trials addressing GI reflux disease (GERD), lower GI symptoms and pancreatic disease were considered. Studies report positive effects of HEMTs on pH levels and bicarbonate secretion as well as improvement on intestinal inflammation. HEMTs also demonstrated positive effects on GERD and lower GI symptoms or conditions CF related such as dysbiosis. Taking ETI during pregnancy could also allow resolution of meconium ileus in fetuses with CF. The best benefits were observed in pancreatic function, potentially delaying CF-related diabetes and recovering pancreatic function in some children on ETI. Larger trials, particularly in pediatric populations, need to confirm these findings and explore long-term effects.

Spontaneous lung colonization in the cystic fibrosis rat model is linked to gastrointestinal obstruction

Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, resulting in CFTR protein dysfunction. CFTR dysfunction has multi-organ consequences, leading to dehydrated mucus that is adherent to epithelia. In the lungs, this leads to recalcitrant infections with bacteria such as Pseudomonas aeruginosa. In the gut, mucus-laden feces can adhere to the intestines, resulting in distal intestinal obstruction syndrome (DIOS). There is limited information on how lung colonization and DIOS are correlated in people with CF (pwCF). In this novel work, we describe the development of spontaneous lung colonization of CF pathogens in young (<3 months old) CF rats, preceding the development of DIOS. Once DIOS is established, the lung microbiome becomes predominated by taxa also observed in the feces. Induced infection with P. aeruginosa in the CF rats reflects data found in pwCF, as once CF rats are infected, they retain a higher relative abundance of P. aeruginosa than their healthy agemates. Finally, we found that ivacaftor treatment favors a healthier gut microbiome in CF rats, decreasing the relative abundance of Escherichia coli. These results indicate that the CF rat model is recapitulative of human CF disease with the spontaneous lung colonization of traditional CF pathogens and maintenance of P. aeruginosa after induced infection. Furthermore, these results indicate a possible role for the gut-lung axis in lung colonization and DIOS in CF.IMPORTANCEThese data describe for the first time the development of spontaneous lung colonization in the cystic fibrosis (CF) rat model, a hallmark aspect of human CF disease. We also find that CF rats infected with Pseudomonas aeruginosa maintain higher relative abundance following chronic infection as compared to healthy rats, similar to those is seen in people with CF. Additionally, we describe the possible contribution of the gut-lung axis linking lung health with distal intestinal obstruction syndrome, a relationship largely unexplored in the context of CF.

Cystic fibrosis-related bone disease: an update on screening, diagnosis, and treatment

Cystic fibrosis-related bone disease (CFBD) is a common endocrinopathy in people living with cystic fibrosis (CF) that is complex and multifactorial in origin. People with CF experience high rates of progressive bone density loss and increased fracture risk. Focus on prevention and treatment of CFBD is of increasing importance in a now aging CF population. This review will discuss current practices in CFBD, gaps in knowledge, and potential future studies with the goal of advancing the clinical care of patients with CFBD.

Elexacaftor-tezacaftor-ivacaftor pharmacokinetics with concurrent tacrolimus administration after lung transplant

BACKGROUND

CFTR modulators in post-transplant people with cystic fibrosis (pwCF) are less frequently used due to uncertainty regarding effectiveness and interactions with immunosuppressive agents. Elexacaftor/tezacaftor/ivacaftor (ETI) is a triple combination cystic fibrosis (CF) therapeutic with benefits in multiple organ systems where complications can impact lung transplant (LTx) outcomes, including malnutrition, diabetes, and sinus disease. ETI use in LTx recipients is variable.

METHODS

We conducted a pharmacokinetics (PK) study of concentrations of ETI parent compounds and the four major metabolites (M23-ELX, M1-TEZ, M1-IVA, M6-IVA) in a prospective non-randomized observational study, with all transplant participants concomitantly taking tacrolimus for LTx immunosuppression and excluded if taking any other medication with known interactions (e.g., azole antifungals) and compared to a non-transplant group of pwCF. We completed non-compartmental analysis (NCA) for both groups and compared the transplant to non-transplant PK parameters, as well as to published data from the manufacturer for non-transplant pwCF. Area under the curve (AUC), average concentrations (Cavg), minimum and maximum concentrations, clearance, and other parameters were determined.

RESULTS

Twelve transplant and fourteen non-transplant participants with CF completed the study. There were no significant differences between the mean values for any PK parameters for the transplant and non-transplant groups and no substantial differences in frequency of concentrations outside the therapeutic ranges in the two groups.

CONCLUSIONS

Our data suggest there are not significant differences in concentrations of ELX, TEZ, IVA, or their major human metabolites in LTx recipients compared to non-transplant pwCF.

Challenges to Optimizing Nutrition in Children With Cystic Fibrosis

PURPOSE OF REVIEW

Cystic fibrosis is a chronic condition that has significant effects on the nutritional status of pediatric patients. Malnutrition is frequently encountered in this population and has been shown to contribute to poor pulmonary and overall disease outcomes. This article will provide an overview of the physiologic and psychosocial challenges toward attaining optimal nutrition in pediatric cystic fibrosis patients.

RECENT FINDINGS

Newer therapies such as CFTR modulators have played significant roles in improving the nutritional status of patients with cystic fibrosis. There is also a greater focus on becoming more aware of psychosocial and cultural barriers in the care of cystic fibrosis patients. Many challenges exist in optimizing nutritional support including but not limited to the patient's clinical manifestations and disease severity, caregiver ability, and access to care. Both gastrointestinal and non-gastrointestinal disorders lead to insufficient caloric intake, increased loss and metabolic needs, and micronutrient and macronutrient deficiency. Social factors including stressful patient and caregiver relationships and altered body image also contribute to poor nutritional status.

Heterogeneity in Reported Side Effects Following Initiation of Elexacaftor-Tezacaftor-Ivacaftor: Experiences at a Quaternary CF Care Center

BACKGROUND

The benefits of Elexecaftor-Tezacaftor-Ivacaftor (ETI) therapy on the health and wellbeing of people with CF (pwCF) are well documented. Since approval, however, a growing number of potential side effects have emerged in reports from clinical practice. With current understanding of ETI tolerability limited to data from clinical trials, the prevalence of side effects and their impact on care decision making remains poorly categorized.

METHODS

A 10-question survey was developed and distributed to patients 18 years or older who were treated at the Massachusetts General Hospital CF centers. Reports of side effects were measured across 12 distinct categories, and dose adjustments and discontinuation due to side effects were collected. If a patient reported no side effects, they did not have to complete the entire survey.

RESULTS

Among 92 respondents initiated on ETI, 51 respondents (55.4%) reported potential side effects and 41 (44.5%) respondents reported no adverse events. The most commonly reported side effects were mental health, changes in appearance, and gastrointestinal complaints, which were reported by 22.8%, 30.4%, and 21.7% of patients, respectively. Eighteen (19.6%) respondents modified their dosing in response to side effects, and six discontinued treatment permanently (6.52%) due to persistent side effects.

CONCLUSIONS

Responses demonstrated marked heterogeneity, with most respondents reporting at least one side effect following initiation. Dose modification was commonly utilized to mitigate adverse effects, however few respondents had to discontinue treatment. These findings demonstrate the importance of monitoring for potential drug-related side effects of ETI in clinical settings.

A review of proton pump inhibitor use in cystic fibrosis and considerations for deprescribing

Use of proton-pump inhibitors (PPIs) is common among people with cystic fibrosis (pwCF) both for the management of suspected GERD, as well as pancreatic enzyme replacement therapy augmentation. Despite their use, limited data exist to demonstrate a clinically significant impact of PPIs on key endpoints in pwCF. Furthermore, the advent of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy may modify the need for use. These notions, coupled with the potential for adverse outcomes associated with long-term PPI use in pwCF, should facilitate re-evaluation of long-term PPI use in pwCF and promote potential deprescribing. Despite limited data on PPI deprescribing in pwCF, it intuitively mirrors the existing guidance in adults in the general population, but with added consideration given to tapering strategy, and monitoring for CF-specific outcomes such as nutritional and respiratory status. The development of a monitoring and re-initiation plan is key to reducing deprescribing inertia. This review aims to summarize the evidence that details the concern for long-term use of PPIs and provide CF clinicians with rationale and guidance on how to approach deprescribing in their practice.

Nutritional status in the era of highly effective CFTR modulators

Advances in cystic fibrosis (CF) diagnostics and therapeutics have led to improved health and longevity, including increased body weight and decreased malnutrition in people with CF. Highly effective CFTR modulator therapies (HEMT) are associated with increased weight through a variety of mechanisms, accelerating trends of overweight and obesity in the CF population. Higher body mass index (BMI) is associated with improved pulmonary function in CF, yet the incremental improvement at overweight and obese BMIs is not clear. Improvements in pulmonary health with increasing BMI are largely driven by increases in fat-free mass (FFM), and impact of HEMT on FFM is uncertain. While trends toward higher weight and BMI are generally seen as favorable in CF, the increased prevalence of overweight and obesity has raised concern for potential risk of traditional age- and obesity-related comorbidities. Such comorbidities, including impaired glucose tolerance, hypertension, cardiac disease, hyperlipidemia, fatty liver, colon cancer, and obstructive sleep apnea, may occur on top of pre-existing CF-related comorbidities. CF nutrition recommendations are evolving in the post-modulator era to more individualized approaches, in contrast to prior blanket high-fat, high-calorie prescriptions for all. Ultimately, it will be essential to redefine goals for optimal weight and nutritional status to allow for holistic health and aging in people with CF.

Evolving data on risk and current screening recommendations for colorectal cancer in cystic fibrosis: Pre- and posttransplant

Advances in treatment for cystic fibrosis (CF), including cystic fibrosis transmembrane conductor regulator (CFTR) modulators, have ushered in an era where patients with CF have much longer life expectancies. This shift in life expectancy demands increased attention to diseases of aging in patients with CF. A notable complication of CF is early-onset colorectal cancer (CRC), which is especially prevalent in patients with severe mutations and after transplant. CFTR acts as a tumor suppressor gene based on knockout models. Lack of CFTR expression promotes carcinogenic processes such as intestinal inflammation and deleterious gut microbiome changes. The consensus Cystic Fibrosis Foundation recommendations advocate treating this population as a high-risk group, using a colonoscopy-only screening strategy starting at age 40 in patients without transplant and at age 30 after transplant. Screening should be considered every 5 years if negative and every 3 years or sooner for patients with adenomatous polyps. Future research will determine the role of noninvasive CRC screening tools in this population, as well as the effects of CFTR modulators on the risk of developing CRC.

Pancreas and pancreatitis: Exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is highly prevalent among individuals with cystic fibrosis (CF). Individuals diagnosed with EPI are often labeled as having "pancreas insufficient cystic fibrosis (PI-CF)" while those with normal exocrine function are labeled as "pancreas sufficient CF (PS-CF)." This diagnosis of EPI relies on clinical and laboratory features and management involves consumption of pancreas enzyme replacement therapy. In this review, we discuss the nuances of diagnosis and management of EPI in CF. We also present emerging evidence on the effects of CFTR modulating agents on the management of EPI, and speculate that these medications may lead to greater heterogeneity in management of EPI in CF moving forward.

Pancreatic enzyme prescription following ivacaftor licensing: A retrospective analysis of the US and UK cystic fibrosis registries

BACKGROUND

Relieving gastrointestinal symptoms is a research priority in cystic fibrosis. Emerging evidence highlights effects of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on gastrointestinal function, including pancreatic sufficiency. This study explores ivacaftor licensing and treatment on recorded pancreatic enzyme replacement therapy (PERT) prescription in the US and UK CF registries.

METHODS

Retrospective longitudinal registry study of recorded pancreatic PERT use between 2008 and 2017. Interrupted time series analysis in propensity-matched cohorts estimated annual change and step change according to ivacaftor eligibility before and after licensing year, 2012. Generalised estimating equations assessed adjusted risk of PERT use in individuals treated with ivacaftor after 2012 compared to untreated individuals.

RESULTS

In the US CF registry, the difference in annual change in prevalence of PERT use post-2012 between eligible cases and ineligible controls was -5.0 per 1000 people/year (95 %CI -7.6; -2.3, p = 0.001). The step change and annual change in prevalence of PERT use in eligible cases was not significantly different to controls in the UK CF registry. Relative to the relationship in 2013, ivacaftor treatment in the US CF registry was associated with a lower adjusted risk ratio of PERT use compared to untreated individuals by 2016 (0.97, 95 %CI 0.96; 0.99), which was not observed in the UK CF registry.

CONCLUSIONS

Licensing of ivacaftor was followed by a lower prevalence of PERT use in the eligible US population compared to pre-licensing period, as well as lower risk of PERT use in those who received treatment. Inconsistencies in US and UK CF registries were observed.

New drugs, new challenges in cystic fibrosis care

Cystic fibrosis (CF) is a genetic disease caused by variants in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, a chloride and bicarbonate channel. CFTR dysfunction results in a multiorgan disease with the main clinical features being exocrine pancreatic insufficiency and diffuse bronchiectasis with chronic airway infection leading to respiratory failure and premature death. Over the past decades, major progress has been made by implementing multidisciplinary care, including nutritional support, airway clearance techniques and antibiotics in specialised CF centres. The past decade has further seen the progressive development of oral medications, called CFTR modulators, for which around 80% of people with CF are genetically eligible in Europe. CFTR modulators partially restore ion transport and lead to a rapid and major improvement in clinical manifestations and lung function, presumably resulting in longer survival. CFTR modulators have been game-changing in the care of people with CF. However, many questions remain unanswered, such as the long-term effects of CFTR modulators, especially when treatment is started very early in life, or the new CF-related disease emerging due to CFTR modulators. Moreover, severe complications of CF, such as diabetes or cirrhosis, are not reversed on CFTR modulators and around 20% of people with CF bear CFTR variants leading to a CFTR protein that is unresponsive to CFTR modulators. Challenges also arise in adapting CF care to a changing disease. In this review article, we highlight the new questions and challenges emerging from this revolution in CF care.

DRA involvement in linaclotide-stimulated bicarbonate secretion during loss of CFTR function

Duodenal bicarbonate secretion is critical to epithelial protection, as well as nutrient digestion and absorption, and is impaired in cystic fibrosis (CF). We examined if linaclotide, typically used to treat constipation, may also stimulate duodenal bicarbonate secretion. Bicarbonate secretion was measured in vivo and in vitro using mouse and human duodenum (biopsies and enteroids). Ion transporter localization was identified with confocal microscopy, and de novo analysis of human duodenal single-cell RNA sequencing (scRNA-Seq) data sets was performed. Linaclotide increased bicarbonate secretion in mouse and human duodenum in the absence of cystic fibrosis transmembrane conductance regulator (CFTR) expression (Cftr-knockout mice) or function (CFTRinh-172). Na+/H+ exchanger 3 inhibition contributed to a portion of this response. Linaclotide-stimulated bicarbonate secretion was eliminated by down-regulated in adenoma (DRA, SLC26A3) inhibition during loss of CFTR activity. ScRNA-Seq identified that 70% of villus cells expressed SLC26A3, but not CFTR, mRNA. Loss of CFTR activity and linaclotide increased apical brush border expression of DRA in non-CF and CF differentiated enteroids. These data provide further insights into the action of linaclotide and how DRA may compensate for loss of CFTR in regulating luminal pH. Linaclotide may be a useful therapy for CF individuals with impaired bicarbonate secretion.

Evolution of nutritional management in children with cystic fibrosis - a narrative review

Nutrition has played a central role in the management and outcomes of people with cystic fibrosis (pwCF) since the 1970s. Advances in therapies and practices in recent decades have led to a significant change in the patient landscape with dramatic improvements in life expectancy, as well as quality of life, bringing with it new issues. Historically, cystic fibrosis was a condition associated with childhood and malnutrition; however, changes in patient demographics, nutritional assessment and fundamental nutritional management have evolved, and it has become an increasingly prevalent adult disease with new nutritional challenges, including obesity. This paper aims to describe these changes and the impact and challenges they bring for those working in this field. Nutritional professionals will need to evolve, adapt and remain agile to the wider range of situations and support required for a new generation of pwCF. Specialised nutrition support will continue to be required, and it will be additionally important to improve and optimise quality of life and long-term health.

Alterations in exocrine pancreatic function after acute pancreatitis

Exocrine pancreatic dysfunction (EPD) is a malabsorptive complication of pancreatic disorders that can lead to a host of symptoms ranging from flatulence to diarrhea and contribute to weight loss and metabolic bone disease. It is increasingly recognized to occur after acute pancreatitis (AP), including episodes with mild severity. The risk of developing EPD after AP is influenced by a range of factors, including the degree of acinar cell destruction and inflammation during AP, and persistent structural derangements following AP. In this article, we discuss the epidemiology, pathophysiology, and clinical management of EPD after AP while highlighting key knowledge gaps.

Predicting weight gain in patients with cystic fibrosis on triple combination modulator

BACKGROUND

Cystic fibrosis (CF) is caused by CF transmembrane conductance regulator (CFTR) gene mutations producing dysfunctional CFTR proteins leading to progressive clinical disease. Elexacaftor-tezacaftor-ivacaftor (ETI) remarkably improves lung disease but is associated with substantial weight gain.

STUDY DESIGN AND METHODS

We performed a single-center longitudinal study predicting 6-month weight gain after ETI initiation. We used linear mixed effects modeling (LME) to determine association of ETI treatment with changing body mass index (BMI). Using linear regression, we examined BMI prediction models with distinct combinations of main effects to identify a model useful for patient counseling. We used up to eight commonly observed clinical characteristics as input variables (age, sex, percent predicted FEV1 [FEV1%], F508del homozygous state, pancreatic sufficiency, HgbA1c, prior modulator use and prior year number of pulmonary exacerbations).

RESULTS

We evaluated 154 patients (19-73 years old, 54% female, FEV1% = 19-121, 0-6 prior year pulmonary exacerbations). LME demonstrated an association between ETI use and weight increases. Exhaustive testing suggested a parsimonious linear regression model well-fitted to data that is potentially useful for counseling. The two variable model shows that on average, BMI decreases by 0.045 (95% Confidence Interval [CI] = -0.069 to -0.021, p < 0.001) for every year of age and increases by 0.322 (CI = 0.142 to 0.502, p = 0.001) for each additional prior year exacerbation at the time of ETI initiation.

INTERPRETATION

Young patients with many prior year pulmonary exacerbations likely have the largest 6 month weight gain after starting ETI.

Changes in fecal lipidome after treatment with ivacaftor without changes in microbiome or bile acids

BACKGROUND

Alterations in gastrointestinal health are prominent manifestations of cystic fibrosis (CF) and can independently impact pulmonary function. Ivacaftor has been associated with robust improvements in pulmonary function and weight gain, but less is known about the impact of ivacaftor on the fecal microbiome, lipidome, and bile acids.

METHODS

Stool samples from 18 patients with CF and gating mutations (ages 6-61 years, 13 pancreatic insufficient) were analyzed for fecal microbiome and lipidome composition as well as bile acid concentrations at baseline and after 3 months of treatment with ivacaftor. Microbiome composition was also assessed in a healthy reference cohort.

RESULTS

Alpha and beta diversity of the microbiome were different between CF and reference cohort at baseline, but no treatment effect was seen in the CF cohort between baseline and 3 months. Seven lipids increased with treatment. No differences were seen in bile acid concentrations after treatment in CF. At baseline, 403 lipids and unconjugated bile acids were different between pancreatic insufficient (PI-CF) and sufficient (PS-CF) groups and 107 lipids were different between PI-CF and PS-CF after 3 months of treatment.

CONCLUSIONS

The composition and diversity of the fecal microbiome were different in CF as compared to a healthy reference, and did not change after 3 months of ivacaftor. We detected modest differences in the fecal lipidome with treatment. Differences in lipid and bile acid profiles between PS-CF and PI-CF were attenuated after 3 months of treatment.

Reduction in abdominal symptoms (CFAbd-Score), faecal M2-pyruvate-kinase and Calprotectin over one year of treatment with Elexacaftor-Tezacaftor-Ivacaftor in people with CF aged ≥12 years - The RECOVER study

BACKGROUND

RECOVER is a multicentre post-approval study of Elexacaftor/Tezacaftor/Ivacaftor (ETI) in pwCF in Ireland and the UK. The CFAbd-Score is the first validated CF-specific patient reported outcome measure (PROM) focusing on gastrointestinal symptoms; it comprises 28 items in 5 domains. In a preliminary study, we previously reported reductions in abdominal symptoms (AS) in pwCF after 26 weeks of ETI-therapy using the CFAbd-Score.

AIM

to assess changes in AS in a second, large cohort and explore novel GI-biomarkers of gut inflammation and cell-proliferation in pwCF over one year of ETI-therapy.

METHODS

Participants were recruited as part of the RECOVER study at 8 sites (Ireland&UK). The CFAbd-Score was administered prior to ETI-initiation, and subsequently at 1,2,6 and 12 months on treatment. Faecal M2-pyruvate kinase (M2-PK) and calprotectin (FC) were quantified in samples collected at baseline, 1 and 6 months.

RESULTS

108 CFAbd-Scores and 73 stool samples were collected at baseline. After 12 months of ETI-therapy, total CFAbd-Scores had significantly declined (15.0±1.4→9.8±1.2pts/p<0.001), and so had all its five domains of "pain" (16.9±2.0pts→9.9±1.8pts/p<0.01), "GERD" (14.4±1.8→9.9±1.6/p<0.05), "disorders of bowel movements" (19.2±1.4→14.1±1.5/p<0.01), "appetite" (7.0±1.1→4.6±1.2/p<0.01) and "impaired-QoL" (13.3±1.9→7.5±1.5/p<0.001). Levels of M2-PK and FC significantly decreased during ETI-therapy.

DISCUSSION

In-depth analysis of AS with the CFAbd-Score reveals a statistically significant, clinically relevant and sustained improvement with ETI. We attribute this to high sensitivity of the implemented CF-specific PROM, developed and validated following FDA-guidelines. Furthermore, for the first time during ETI-therapy a significant decline in faecal M2-PK, a marker of inflammation and cell-proliferation, was found, in parallel to FC.

Key role of down-regulated in adenoma (SLC26A3) chloride/bicarbonate exchanger in linaclotide-stimulated intestinal bicarbonate secretion upon loss of CFTR function

Duodenal bicarbonate secretion is critical to epithelial protection, nutrient digestion/absorption and is impaired in cystic fibrosis (CF). We examined if linaclotide, typically used to treat constipation, may also stimulate duodenal bicarbonate secretion. Bicarbonate secretion was measured in vivo and in vitro using mouse and human duodenum (biopsies and enteroids). Ion transporter localization was identified with confocal microscopy and de novo analysis of human duodenal single cell RNA sequencing (sc-RNAseq) datasets was performed. Linaclotide increased bicarbonate secretion in mouse and human duodenum in the absence of CFTR expression (Cftr knockout mice) or function (CFTRinh-172). NHE3 inhibition contributed to a portion of this response. Linaclotide-stimulated bicarbonate secretion was eliminated by down-regulated in adenoma (DRA, SLC26A3) inhibition during loss of CFTR activity. Sc-RNAseq identified that 70% of villus cells expressed SLC26A3, but not CFTR, mRNA. Loss of CFTR activity and linaclotide increased apical brush border expression of DRA in non-CF and CF differentiated enteroids. These data provide further insights into the action of linaclotide and how DRA may compensate for loss of CFTR in regulating luminal pH. Linaclotide may be a useful therapy for CF individuals with impaired bicarbonate secretion.

Pancreatic enzymes digest obstructive meconium from cystic fibrosis pig intestines

Introduction

Meconium ileus (MI) is a life-threatening obstruction of the intestines affecting ∼15% of newborns with cystic fibrosis (CF). Current medical treatments for MI often fail, requiring surgical intervention. MI typically occurs in newborns with pancreatic insufficiency from CF. Meconium contains mucin glycoprotein, a potential substrate for pancreatic enzymes or mucolytics. Our study aim was to determine whether pancreatic enzymes in combination with mucolytic treatments dissolve obstructive meconium using the CF pig model.

Methods

We collected meconium from CF pigs at birth and submerged it in solutions with and without pancreatic enzymes, including normal saline, 7% hypertonic saline, and the reducing agents N-acetylcysteine (NAC) and dithiothreitol (DTT). We digested meconium at 37 °C with agitation, and measured meconium pigment release by spectrophotometry and residual meconium solids by filtration.

Results and discussion

In CF pigs, meconium appeared as a solid pigmented mass obstructing the ileum. Meconium microscopically contained mucus glycoprotein, cellular debris, and bile pigments. Meconium fragments released pigments with maximal absorption at 405 nm after submersion in saline over approximately 8 h. Pancreatic enzymes significantly increased pigment release and decreased residual meconium solids. DTT did not improve meconium digestion and the acidic reducing agent NAC worsened digestion. Pancreatic enzymes digested CF meconium best at neutral pH in isotonic saline. We conclude that pancreatic enzymes digest obstructive meconium from CF pigs, while hydrating or reducing agents alone were less effective. This work suggests a potential role for pancreatic enzymes in relieving obstruction due to MI in newborns with CF.

Improved Nutritional Outcomes and Gastrointestinal Symptoms in Adult Cystic Fibrosis Patients Treated with Elexacaftor/Tezacaftor/Ivacaftor

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator modulator therapy improves nutritional status and quality of life. Clinical trials have shown pancreatic insufficiency conversion, mostly in pediatric patients treated with ivacaftor. Studies with elexacaftor/tezacaftor/ivacaftor (ETI) in older patients have not suggested restoration of exocrine pancreas function, but quality data in adults are lacking. Our aim was to show the effect of ETI in adults with cystic fibrosis (CF) on nutritional status and digestive function. We hypothesized improvement of nutritional parameters and gastrointestinal symptoms, reduction of pancreatic enzyme replacement therapy, but uncertain improvement in exocrine pancreatic function.

METHODS

We prospectively enrolled adults with CF treated with ETI from August 2021 to June 2022. We measured anthropometric parameters, laboratory nutritional markers, change of fecal elastase, pancreatic enzymes replacement therapy needs, and gastrointestinal symptoms.

RESULTS

In the cohort of 29 patients (mean age 29.1 years), 82.8% suffered exocrine pancreatic insufficiency. After ETI, mean BMI increased by 1.20 kg/m2 (p < 0.001), mean body weight by 3.51 kg (p < 0.001), albumin by 2.81 g/L, and prealbumin by 0.06 (both p < 0.001). Only 1 patient, initially pancreatic insufficient (4.5%, p < 0.001), developed pancreatic sufficiency, indicated by increased fecal elastase from 45 μg/g to 442.1 μg/g. Mean change in lipase substitution decreased by 1,969 units/kg/day (p < 0.001) and stools frequency by 1.18 per day (p < 0.001).

CONCLUSION

Our data suggest increased nutritional parameters, lower pancreatic substitution requirements, and improved defecation in adult CF patients on ETI. Improvement in exocrine pancreatic function might be mutation-specific and needs further study.

Bicarbonate secretion and acid/base sensing by the intestine

The transport of bicarbonate across the enterocyte cell membrane regulates the intracellular as well as the luminal pH and is an essential part of directional fluid movement in the gut. Since the first description of "active" transport of HCO3- ions against a concentration gradient in the 1970s, the fundamental role of HCO3- transport for multiple intestinal functions has been recognized. The ion transport proteins have been identified and molecularly characterized, and knockout mouse models have given insight into their individual role in a variety of functions. This review describes the progress made in the last decade regarding novel techniques and new findings in the molecular regulation of intestinal HCO3- transport in the different segments of the gut. We discuss human diseases with defects in intestinal HCO3- secretion and potential treatment strategies to increase luminal alkalinity. In the last part of the review, the cellular and organismal mechanisms for acid/base sensing in the intestinal tract are highlighted.

Cystic fibrosis and fat malabsorption: Pathophysiology of the cystic fibrosis gastrointestinal tract and the impact of highly effective CFTR modulator therapy

Cystic fibrosis (CF) is a progressive, genetic, multi-organ disease affecting the respiratory, digestive, endocrine, and reproductive systems. CF can affect any aspect of the gastrointestinal (GI) tract, including the esophagus, stomach, small intestine, colon, pancreas, liver, and gall bladder. GI pathophysiology associated with CF results from CF membrane conductance regulator (CFTR) dysfunction. The majority of people with CF (pwCF) experience exocrine pancreatic insufficiency resulting in malabsorption of nutrients and malnutrition. Additionally, other factors can cause or worsen fat malabsorption, including the potential for short gut syndrome with a history of meconium ileus, hepatobiliary diseases, and disrupted intraluminal factors, such as inadequate bile salts, abnormal pH, intestinal microbiome changes, and small intestinal bacterial overgrowth. Signs and symptoms associated with fat malabsorption, such as abdominal pain, bloating, malodorous flatus, gastroesophageal reflux, nausea, anorexia, steatorrhea, constipation, and distal intestinal obstruction syndrome, are seen in pwCF despite the use of pancreatic enzyme replacement therapy. Given the association of poor nutrition status with lung function decline and increased mortality, aggressive nutrition support is essential in CF care to optimize growth in children and to achieve and maintain a healthy body mass index in adults. The introduction of highly effective CFTR modulator therapy and other advances in CF care have profoundly changed the course of CF management. However, GI symptoms in some pwCF may persist. The use of current knowledge of the pathophysiology of the CF GI tract as well as appropriate, individualized management of GI symptoms continue to be integral components of care for pwCF.

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).

Impact of elexacaftor/tezacaftor/ivacaftor on lipid and fat-soluble vitamin levels and association with body mass index

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve gastrointestinal absorption of nutrients and may result in changes in body mass index (BMI), serum lipids, and fat-soluble vitamin levels. We hypothesized that serum lipids and vitamin levels would increase with CFTR modulator therapy and that greater increase in lipids and vitamin levels would be related to greater increase in BMI.

METHODS

A retrospective study was performed to evaluate the impact of elexacaftor/tezacaftor/ivacaftor (ETI) on nutritional parameters, serum lipids, and fat-soluble vitamin levels. Pre-ETI values (<2 years prior) and post-ETI values (>1 month after) were compared. Linear regression was used to evaluate whether change in BMI is associated with the change in lipid and/or vitamin levels and whether modulator duration is associated with the degree of rise in lipid and/or vitamin levels.

RESULTS

Adults and adolescents with CF (n = 137) were evaluated before and 31-300 days after starting ETI. Median BMI (adults 21.9 vs. 23.5 kg/m2 ; adolescents 48 vs. 63 percentile) increased after initiation of ETI. Total cholesterol (126 vs. 154 mg/dL), low-density lipoprotein cholesterol (63 vs. 78 mg/dL), non-high-density lipoprotein cholesterol (84 vs. 102 mg/dL), and high density lipoprotein cholesterol (43 vs. 49 mg/dL) increased after ETI, while triglycerides and very low density lipoprotein did not change. Median values for vitamin D (34.5 vs. 38.0 ng/mL) and vitamin A (40.1 vs. 47.9 µg/dL) increased, while vitamin E did not change significantly. There was no significant correlation between BMI change or duration of modulator therapy with vitamin levels or lipid changes.

CONCLUSION

After initiation of ETI therapy, serum lipids increased in our population, but most values remained within the normal range. Vitamins A and D levels increased post-ETI and no changes were noted in vitamin E. No significant correlation between the degree of BMI change and the magnitude of increase in lipids or vitamin levels was found.

Longitudinal profiling of the intestinal microbiome in children with cystic fibrosis treated with elexacaftor-tezacaftor-ivacaftor

The intestinal microbiome influences growth and disease progression in children with cystic fibrosis (CF). Elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA), the newest pharmaceutical modulator for CF, restores the function of the pathogenic mutated CF transmembrane conductance regulator (CFTR) channel. We performed a single-center longitudinal analysis of the effect of ELX/TEZ/IVA on the intestinal microbiome, intestinal inflammation, and clinical parameters in children with CF. Following ELX/TEZ/IVA, children with CF had significant improvements in body mass index and percent predicted forced expiratory volume in one second, and required fewer antibiotics for respiratory infections. Intestinal microbiome diversity increased following ELX/TEZ/IVA coupled with a decrease in the intestinal carriage of Staphylococcus aureus, the predominant respiratory pathogen in children with CF. There was a reduced abundance of microbiome-encoded antibiotic resistance genes. Microbial pathways for aerobic respiration were reduced after ELX/TEZ/IVA. The abundance of microbial acid tolerance genes was reduced, indicating microbial adaptation to increased CFTR function. In all, this study represents the first comprehensive analysis of the intestinal microbiome in children with CF receiving ELX/TEZ/IVA.IMPORTANCECystic fibrosis (CF) is an autosomal recessive disease with significant gastrointestinal symptoms in addition to pulmonary complications. Recently approved treatments for CF, CF transmembrane conductance regulator (CFTR) modulators, are anticipated to substantially improve the care of people with CF and extend their lifespans. Prior work has shown that the intestinal microbiome correlates with health outcomes in CF, particularly in children. Here, we study the intestinal microbiome of children with CF before and after the CFTR modulator, ELX/TEZ/IVA. We identify promising improvements in microbiome diversity, reduced measures of intestinal inflammation, and reduced antibiotic resistance genes. We present specific bacterial taxa and protein groups which change following ELX/TEZ/IVA. These results will inform future mechanistic studies to understand the microbial improvements associated with CFTR modulator treatment. This study demonstrates how the microbiome can change in response to a targeted medication that corrects a genetic disease.

A grumbling concern: A survey of gastrointestinal symptoms in cystic fibrosis in the modulator era

Background

Gastrointestinal symptoms in cystic fibrosis (CF) are common and intrusive to daily life. Relieving gastrointestinal symptoms was identified as an important research priority and previously explored in an international survey in 2018. However, following the widespread introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators in 2019, the landscape of CF treatment has changed. We repeated an online survey to further describe gastrointestinal symptoms and their effect on quality of life (QoL) in the CFTR modulator era.

Methods

An electronic survey consisting of closed questions and free text responses was distributed via social media and professional networks for a period of one month between March - April 2022. People with CF (pwCF), their family and friends, and healthcare professionals (HCPs) were invited to take part.

Results

There were 164 respondents: 88 pwCF (54%), 22 (13%) family, and 54 (33%) healthcare professionals (HCPs). A total of 89/110 (81%) pwCF or family members reported CFTR modulator treatment. The most commonly reported symptoms were wind / gas and rumbling stomach noises (borborygmi) in both the modulator and non-modulator groups in addition to loose motions (modulator group) and bloating (no modulator group). Abdominal pain and bloating had the greatest impact on QoL.For those on a CFTR modulator, the proportion of pwCF reporting "no change" or "worse" for all of the symptoms surveyed was greater than the proportion reporting an improvement. For some symptoms such as stomach pains and reduced appetite, improvements were perceived more commonly in HCPs than what was reported by pwCF. Following modulator introduction, dietary changes to manage GI symptoms were recommended by 28/35 (80%) of HCPs and reported by 38/76 (50%) lay respondents. Changes in medication were recommended by 19/35 (54%) HCPs and reported by 44/76 (58%) of patients and family members.

Conclusion

This survey has shown that gastrointestinal symptoms remain prevalent in pwCF in the CFTR modulator era, though the nature of these symptoms may have changed. A better understanding of the underlying pathophysiology of these symptoms is essential. Future clinical studies should focus on improving symptoms and QoL.

ESPEN-ESPGHAN-ECFS guideline on nutrition care for cystic fibrosis

BACKGROUND

Nutritional status is paramount in Cystic Fibrosis (CF) and is directly correlated with morbidity and mortality. The first ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with CF were published in 2016. An update to these guidelines is presented.

METHODS

The study was developed by an international multidisciplinary working group in accordance with officially accepted standards. Literature since 2016 was reviewed, PICO questions were discussed and the GRADE system was utilized. Statements were discussed and submitted for on-line voting by the Working Group and by all ESPEN members.

RESULTS

The Working Group updated the nutritional guidelines including assessment and management at all ages. Supplementation of vitamins and pancreatic enzymes remains largely the same. There are expanded chapters on pregnancy, CF-related liver disease, and CF-related diabetes, bone disease, nutritional and mineral supplements, and probiotics. There are new chapters on nutrition with highly effective modulator therapies and nutrition after organ transplantation.

An in vitro medium for modeling gut dysbiosis associated with cystic fibrosis

The gut physiology of pediatric and adult persons with cystic fibrosis (pwCF) is altered relative to healthy persons. The CF gut is characterized, in part, as having excess mucus, increased fat content, acidic pH, increased inflammation, increased antibiotic perturbation, and the potential for increased oxygen availability. These physiological differences shift nutritional availability and the local environment for intestinal microbes, thus likely driving significant changes in microbial metabolism, colonization, and competition with other microbes. The impact of any specific change in this physiological landscape is difficult to parse using human or animal studies. Thus, we have developed a novel culture medium representative of the CF gut environment, inclusive of all the aforementioned features. This medium, called CF-MiPro, maintains CF gut microbiome communities, while significantly shifting nonCF gut microbiome communities toward a CF-like microbial profile, characterized by low Bacteroidetes and high Proteobacteria abundance. This medium is able to maintain this culture composition for up to 5 days of passage. Additionally, microbial communities passaged in CF-MiPro produce significantly less immunomodulatory short-chain fatty acids (SCFA), including propionate and butyrate, than communities passaged in MiPro, a culture medium representative of healthy gut physiology, confirming not only a shift in microbial composition but also altered community function. Our results support the potential for this in vitro culture medium as a new tool for the study of CF gut dysbiosis. IMPORTANCE Cystic fibrosis is an autosomal recessive disease that disrupts ion transport at mucosal surfaces, leading to mucus accumulation and altered physiology of both the lungs and the intestines, among other organs, with the resulting altered environment contributing to an imbalance of microbial communities. Culture media representative of the CF airway have been developed and validated; however, no such medium exists for modeling the CF intestine. Here, we develop and validate a first-generation culture medium inclusive of features that are altered in the CF colon. Our findings suggest this novel medium, called CF-MiPro, as a maintenance medium for CF gut microbiome samples and a flexible tool for studying key drivers of CF-associated gut dysbiosis.

Diagnosis and Management of Gastrointestinal Manifestations in Children with Cystic Fibrosis

Cystic fibrosis (CF) is primarily known for its pulmonary consequences, which are extensively explored in the existing literature. However, it is noteworthy that individuals with CF commonly display gastrointestinal (G-I) manifestations due to the substantial presence of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the intestinal tract. Recognized as pivotal nonpulmonary aspects of CF, G-I manifestations exhibit a diverse spectrum. Identifying and effectively managing these manifestations are crucial for sustaining health and influencing the overall quality of life for CF patients. This review aims to synthesize existing knowledge, providing a comprehensive overview of the G-I manifestations associated with CF. Each specific G-I manifestation, along with the diagnostic methodologies and therapeutic approaches, is delineated, encompassing the impact of innovative treatments targeting the fundamental effects of CF on the G-I tract. The findings underscore the imperative for prompt diagnosis and meticulous management of G-I manifestations, necessitating a multidisciplinary team approach for optimal care and enhancement of the quality of life for affected individuals. In conclusion, the authors emphasize the urgency for further clinical studies to establish a more robust evidence base for managing G-I symptoms within the context of this chronic disease. Such endeavors are deemed essential for advancing understanding and refining the clinical care of CF patients with G-I manifestations.

A Cross-Sectional Study of Pediatric Feeding Disorder in Children with Cystic Fibrosis

BACKGROUND

The exact prevalence of feeding problems in children with cystic fibrosis (CF) is unknown. Pediatric feeding disorder (PFD) encompasses poor oral intake with associated medical, nutrition, psychosocial, or feeding skill dysfunction. We hypothesized that PFD is common in CF and aimed to categorize feeding dysfunction across various domains in children with CF.

METHODS

An observational cross-sectional study was conducted in children with CF. Data collected included anthropometrics, nutrition data (including need for tube feeding/enteral nutrition [EN] or high-energy beverages, dietary diversity), feeding skills (Pediatric version of the Eating Assessment tool [pEAT]), and psychosocial function (About Your Child's Eating questionnaire [AYCE] in children 2-17 years of age/Behavioral Pediatric Feeding Assessment Scale [BPFAS] in children 12-23 months of age). PFD was defined as poor oral intake with: (a) pEAT score > 5; and/or (b) AYCE or BPFAS score > 2 standard deviation of normative controls; and/or (c) nutrition dysfunction (body mass index/weight-for-length z score < -1 and/or preference of oral high energy beverages or dependence on EN and/or decreased dietary diversity).

RESULTS

Of 103 children in the study, 62 (60.1%) had PFD, 7 children (6.8%) were malnourished, 10 needed EN (9.7%), and 30 (29.1%) needed oral high-energy beverages. Dietary diversity was decreased in 42 children (41.5%), 1 child had feeding skill dysfunction, and 11 (10.8%) met criteria for psychosocial dysfunction.

CONCLUSION

Almost 2/3rd of children with CF have PFD and many have poor dietary diversity. A significant percentage of children rely on EN and oral supplements, but psychosocial dysfunction is less prevalent.

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

Highly effective modulator therapies (HEMTs) have revolutionised the management approach of most patients living with cystic fibrosis (CF) who have access to these therapies. Clinical trials have reported significant improvements across multiorgan systems, with patients surviving longer. However, there are accumulating case reports and observational data describing various adverse events following initiation of HEMTs including drug-to-drug interactions, drug induced liver injury, Stevens-Johnson syndrome, and neurocognitive symptoms including psychosis and depression, which have required discontinuation of therapy. Current clinical trials are assessing efficacy in younger patients with CF, yet long-term studies are also required to better understand the safety profile in the real-world setting across all ages and the impact of HEMT dose alteration or discontinuation.

Longitudinal Profiling of the Intestinal Microbiome in Children with Cystic Fibrosis Treated with Elexacaftor-Tezacaftor-Ivacaftor

The intestinal microbiome influences growth and disease progression in children with cystic fibrosis (CF). Elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA), the newest pharmaceutical modulator for CF, restores function of the pathogenic mutated CFTR channel. We performed a single-center longitudinal analysis of the effect of ELX/TEZ/IVA on the intestinal microbiome, intestinal inflammation, and clinical parameters in children with CF. Following ELX/TEZ/IVA, children with CF had significant improvements in BMI, ppFEV1 and required fewer antibiotics for respiratory infections. Intestinal microbiome diversity increased following ELX/TEZ/IVA coupled with a decrease in the intestinal carriage of Staphylococcus aureus, the predominant respiratory pathogen in children with CF. There was a reduced abundance of microbiome-encoded antibiotic-resistance genes. Microbial pathways for aerobic respiration were reduced after ELX/TEZ/IVA. The abundance of microbial acid tolerance genes was reduced, indicating microbial adaptation to increased CFTR function. In all, this study represents the first comprehensive analysis of the intestinal microbiome in children with CF receiving ELX/TEZ/IVA.

A Novel Co-Culture Model Reveals Enhanced CFTR Rescue in Primary Cystic Fibrosis Airway Epithelial Cultures with Persistent Pseudomonas aeruginosa Infection

People with cystic fibrosis (pwCF) suffer from chronic and recurring bacterial lung infections that begin very early in life and contribute to progressive lung failure. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which encodes an ion channel important for maintaining the proper hydration of pulmonary surfaces. When CFTR function is ablated or impaired, airways develop thickened, adherent mucus that contributes to a vicious cycle of infection and inflammation. Therapeutics for pwCF, called CFTR modulators, target the CFTR defect directly, restoring airway surface hydration and mucociliary clearance. However, even with CFTR modulator therapy, bacterial infections persist. To develop a relevant model of diseased airway epithelium, we established a primary human airway epithelium culture system with persistent Pseudomonas aeruginosa infection. We used this model to examine the effects of CFTR modulators on CFTR maturation, CFTR function, and bacterial persistence. We found that the presence of P. aeruginosa increased CFTR mRNA, protein, and function. We also found that CFTR modulators caused a decrease in P. aeruginosa burden. These results demonstrate the importance of including live bacteria to accurately model the CF lung, and that understanding the effects of infection on CFTR rescue by CFTR modulators is critical to evaluating and optimizing drug therapies for all pwCF.

Nutritional considerations for a new era: A CF foundation position paper

OBJECTIVE

To provide interim advice and considerations to the CF Community around CF nutrition in the current era.

METHODS

The Cystic Fibrosis (CF) Foundation organized a multidisciplinary committee to develop a Nutrition Position Paper based on the rapidly changing nutrition landscape in CF, due in part to widespread use of cystic fibrosis transmembrane regulator highly effective modulator therapy (HEMT). Four workgroups were formed: Weight Management, Eating Behavior/Food Insecurity, Salt Homeostasis and Pancreatic Enzyme use. Each workgroup conducted their own focused review of the literature.

RESULTS

The committee summarized current understanding of issues pertaining to the four workgroup topics and provided 6 key take-aways around CF Nutrition in the new era.

CONCLUSION

People with CF (pwCF) are living longer, particularly with the advent of HEMT. The traditional high fat, high calorie CF diet may have negative nutritional and cardiovascular consequences as pwCF age. Individuals with CF may have poor diet quality, food insecurity, distorted body image, and an higher incidence of eating disorders. An increase in overweight and obesity may lead to new considerations for nutritional management, given potential effects of overnutrition on pulmonary and cardiometabolic parameters.

The effect of elexacaftor/tezacaftor/ivacaftor on non-pulmonary symptoms in adults with cystic fibrosis

Background

Elexacaftor/Tezacaftor/Ivacaftor (ETI) is a CFTR modulator that has led to large benefits in lung function, pulmonary exacerbation rates, and respiratory symptoms. Less is known about the effect of ETI on non-pulmonary symptoms. The objective of this study was to examine the changes in patient reported outcomes after starting ETI in multiple non-pulmonary symptoms.

Methods

This was a prospective cohort study of adults with CF. Participants completed questionnaires prior to starting ETI and then at weeks 2, 4, 6, 8, 10, 12, and 14 after starting ETI. They completed the following validated instruments: PROMIS Pain Intensity, PROMIS Pain Interference, FACIT Fatigue, SNOT22, PAC-SYM, PHQ8, GAD7 and Pittsburgh Sleep Quality Index. Longitudinal changes for outcomes were modelled using linear regression based on general estimating equations.

Results

22 participants enrolled who answered questionnaires before and after starting ETI. The median age was 35.3 years (IQR 11.1) and 13 (59.1%) were male. In models adjusted for age, sex, and baseline value there were significant improvements in pain interference (β = -2.57; 95% CI -4.92, -0.23), sinus symptoms (β = -4.50; 95% CI -7.59, -1.41), and sleep disturbance (β = -1.90; 95% CI -2.71, -1.09) over 14 weeks after starting ETI. No symptom areas worsened over the study period.

Conclusions

In this prospective study we found statistically significant improvements in three different non-pulmonary symptom areas in people with CF started on ETI. While this was a small, uncontrolled study it suggests that use of highly effective CFTR modulators can result in benefits for patients beyond pulmonary symptoms.

Cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disease caused by variants in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR dysfunction results in abnormal chloride and bicarbonate transport in epithelial cells, leading to a multiorgan disease dominated by respiratory and digestive manifestations. The respiratory disease, which is characterized by airway mucus plugging, chronic bacterial infection and progressive development of bronchiectasis, may lead to chronic respiratory failure, which is the main cause of premature death in people with CF. Over the past 50 years, major progress has been obtained by implementing multidisciplinary care, including nutritional support, airway clearance techniques and antibiotics in specialized CF centers. The past 10 years have further seen the progressive development of oral medications, called CFTR modulators, that partially restore ion transport and lead to a major improvement in clinical manifestations and lung function, presumably resulting in longer survival. Although an increasing proportion of people with CF are being treated with CFTR modulators, challenges remain regarding access to CFTR modulators due to their high cost, and their lack of marketing approval and/or effectiveness in people with rare CFTR variants. The anticipated increase in the number of adults with CF and their aging also challenge the current organization of CF care. The purpose of this review article is to describe current status and future perspective of CF disease and care.

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.

An In Vitro Medium for Modeling Gut Dysbiosis Associated with Cystic Fibrosis

The gut physiology of pediatric and adult persons with cystic fibrosis (pwCF) is altered relative to healthy persons. The CF gut is characterized, in part, as having excess mucus, increased fat content, acidic pH, increased inflammation, increased antibiotic perturbation and the potential for increased oxygen availability. These physiological differences shift nutritional availability and the local environment for intestinal microbes, thus likely driving significant changes in microbial metabolism, colonization and competition with other microbes. The impact of any specific change in this physiological landscape is difficult to parse using human or animal studies. Thus, we have developed a novel culture medium representative of the CF gut environment, inclusive of all the aforementioned features. This medium, called CF-MiPro, maintains CF gut microbiome communities, while significantly shifting non-CF gut microbiome communities toward a CF-like microbial profile, characterized by low Bacteroidetes and high Proteobacteria abundance. This medium is able to maintain this culture composition for up to 5 days of passage. Additionally, microbial communities passaged in CF-MiPro produce significantly less immunomodulatory short chain fatty acids (SCFA), including propionate and butyrate, than communities passaged in MiPro, a culture medium representative of healthy gut physiology, confirming not only a shift in microbial composition but altered community function. Our results support the potential for this in vitro culture medium as a new tool for the study of gut dysbiosis in CF.

Weight increase in people with cystic fibrosis on CFTR modulator therapy is mainly due to increase in fat mass

Background: Ivacaftor, the first CFTR modulator drug, leads to significant long-term improvement in lung function and weight gain. The mechanism as well as the long-term impact of ivacaftor on weight, resting energy expenditure (REE) and body composition remains to be explored. Methods: This prospective observational study included 18 people with CF (pwCF) (age: median (range) 20 (6-58) years) carrying at least one CFTR gating mutation commencing ivacaftor. Assessments of body composition, REE and laboratory investigations were performed at baseline and 6, 12 and 24 months after treatment initiation. Results: Treatment with ivacaftor was associated with a significantly positive change in BMI z-score at 24 months. Fat mass (mean (95% CL) of 6.5 kg (4.0; 9.0) from baseline, p = 0.0001), but not fat-free mass changed under ivacaftor treatment. There was a significant positive correlation between weight and fat mass change. Overall, there was no significant change in measured REE from baseline (mean (95% CL) of 108 kcal/d (-12; 228), p = 0.07) in our cohort. Pancreatic function and other nutritional markers did not change with treatment, with the exception of an increase in serum vitamin A levels (p = 0.006). Conclusion: The weight gain observed in ivacaftor treated pwCF is predominantly secondary to increases in fat mass warranting early counseling of people starting on CFTR-modulating treatment with respect to healthy diet and physical exercise.

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.

Cystic fibrosis related diabetes (CFRD) in the era of modulators: A scoping review

Cystic fibrosis-related diabetes (CFRD) is a common complication of CF that increases in incidence as patients age. Poor glycemic control has been shown to negatively impact lung function and weight, resulting in higher risk of recurrent pulmonary exacerbations. With the advent of highly effective modulator therapies (HEMT), patients with CF are living longer and healthier lives. Consequently, CFRD and its microvascular complications are rising in prominence, becoming one of the most urgent clinical concerns. As HEMT were developed with the primary focus of improving pulmonary outcomes, it is not clear from the original phase III studies what the short- or long-term benefits of modulators might be on CFRD development and trajectory. In this review, we will examine the pathophysiology of CFRD, summarize and synthesize the available evidence of HEMT impact on CFRD and describe the emerging research needs in this field.

Beyond the Lungs-Emerging Challenges in Adult Cystic Fibrosis Care

Cystic fibrosis (CF) is a multisystem disease. This article provides an up-to-date review of many of the nonrespiratory complications of CF, including mental health issues, nutritional and gastrointestinal problems, fertility issues, diabetes mellitus, bone health and musculoskeletal problems, liver disease, renal problems, and risk of malignancy. It highlights the recent impact of new therapies, including CF transmembrane conductance regulator modulators, on the nonrespiratory complications of CF and provides insights into the potential challenges faced by an aging population of adults with CF and their caregivers, including the potential future risk for cardiovascular disease.

Need to study simplification of gastrointestinal medication regimen in cystic fibrosis in the era of highly effective modulators

INTRODUCTION

The success of highly effective modulator therapy (HEMT) has led to consideration of simpler regimens for people with CF (PwCF) with opportunities to modify burdensome regimens. Despite the intuitive appeal of discontinuing chronic therapies no longer necessary, this process should be pursued systematically to ensure safety, adherence, and validate patient-centered preferences. We designed a questionnaire to determine the state of use of acid-suppressive medications (ASM) and pancreatic enzyme therapy (PERT), current self-withdrawal and provider-directed withdrawal practices, and interest in a standardized withdrawal study.

METHODS

In collaboration with CF Foundation (CFF), a questionnaire was developed and distributed to members of Community Voice (CV, comprised of PwCF and their loved ones), and CF providers regarding the need to study simplifying the gastrointestinal (GI) regimen for PwCF on HEMT.

RESULTS

Approximately 20-40% of CV or CF providers have decreased or stopped ASM for those on HEMT. For PERT, CV and CF providers have decreased dose (34%-48% and approximately 25%, respectively) more often than having stopped it altogether (13%-24% and 3%-12%, respectively). Cumulatively, there is interest in pursuing research in this area (86% CV and 89% CF providers) and willingness to enroll in such a study (80% CV and 89% CF providers).

CONCLUSION

Systematically studying the withdrawal of common GI medications, ASM and PERT, is important to CV and CF providers. Decreases in dosing and withdrawal are already taking place without evidence to support this practice. This questionnaire is the first step in designing a GI medication simplification study in PwCF on HEMT.

CFTR-beyond the airways: Recent findings on the role of the CFTR channel in the pancreas, the intestine and the kidneys

With increased longevity of patients suffering from cystic fibrosis, and widespread lung transplantation facilities, the sequelae of defective CFTR in other organs than the airways come to the fore. This minireview highlights recent scientific progress in the understanding of CFTR function in the pancreas, the intestine and the kidney, and explores potential therapeutic strategies to combat defective CFTR function in these organs.

Cystic fibrosis transmembrane conductance regulator modulators and the exocrine pancreas: A scoping review

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve pulmonary outcomes in subjects with cystic fibrosis (CF); however, the effects on pancreatic manifestations are not well characterized. We hypothesized that CFTR modulators would improve measures of exocrine pancreatic function and outcomes.

METHODS

We performed a systematic search to identify studies reporting measures of the exocrine pancreas in humans treated with CFTR modulators. Only studies reporting baseline and on-treatment assessments were included.

RESULTS

Of 630 identified studies, 41 met inclusion criteria. CFTR modulators reduced acute pancreatitis events by 85% overall (rate ratio 0.15, 95% confidence interval (CI) 0.04, 0.52), with a greater effect seen in the subgroup with pancreas sufficient CF (PS-CF) (rate ratio 0.13 (95% CI 0.03, 0.53). Among 293 subjects with baseline and on-treatment evaluation of pancreas sufficiency, 253 were pancreas insufficient at baseline and 54 (21.3%) converted to pancreas sufficiency. Of 32 subjects with baseline FE-1 values <200 mcg/g, 16 (50%) increased to ≥200 mcg/g. Serum trypsin decreased by a mean of 565.9 ng/mL (standard deviation (SD) 311.8), amylase decreased by 38.2 U/L (SD 57.6), and lipase decreased by 232.3 U/L (SD 247.7).

CONCLUSIONS

CFTR modulator use reduces acute pancreatitis frequency and improves indirect measures of exocrine pancreas function. Future interventional studies that evaluate the mechanism and impact of CFTR modulators on acute pancreatitis and pancreas sufficiency in patients with CFTR dysfunction are warranted.

Nutritional Care in Children with Cystic Fibrosis

Patients with cystic fibrosis (CF) are prone to malnutrition and growth failure, mostly due to malabsorption caused by the derangement in the chloride transport across epithelial surfaces. Thus, optimal nutritional care and support should be an integral part of the management of the disease, with the aim of ameliorating clinical outcomes and life expectancy. In this report, we analyzed the nutrition support across the different ages, in patients with CF, with a focus on the relationships with growth, nutritional status, disease outcomes and the use of the CF transmembrane conductance regulator (CFTR) modulators. The nutrition support goal in CF care should begin as early as possible after diagnosis and include the achievement of an optimal nutritional status to support the growth stages and puberty development in children, that will further support the maintenance of an optimal nutritional status in adult life. The cornerstone of nutrition in patients with CF is a high calorie, high-fat diet, in conjunction with a better control of malabsorption due to pancreatic enzyme replacement therapy, and attention to the adequate supplementation of fat-soluble vitamins. When the oral caloric intake is not enough for reaching the anthropometric nutritional goals, supplemental enteral feeding should be initiated to improve growth and the nutritional status. In the last decade, the therapeutic possibilities towards CF have grown in a consistent way. The positive effects of CFTR modulators on nutritional status mainly consist in the improvement in weight gain and BMI, both in children and adults, and in an amelioration in terms of the pulmonary function and reduction of exacerbations. Several challenges need to be overcome with the development of new drugs, to transform CF from a fatal disease to a treatable chronic disease with specialized multidisciplinary care.

Cystic Fibrosis-Related Gut Dysbiosis: A Systematic Review

BACKGROUND AND AIMS

Cystic Fibrosis (CF) is associated with gut dysbiosis, local and systemic inflammation, and impaired immune function. Gut microbiota dysbiosis results from changes in the complex gut milieu in response to CF transmembrane conductance regulator (CFTR) dysfunction, pancreatic malabsorption, diet, medications, and environmental influences. In several diseases, alteration of the gut microbiota influences local and systemic inflammation and disease outcomes. We conducted a systematic review of the gut microbiota in CF and explored factors influencing dysbiosis.

METHODS

An electronic search of three databases was conducted in January 2019, and re-run in June 2021. Human, animal, and in vitro studies were included. The primary outcome was differences in the gut microbiota between people with CF (pwCF) and healthy controls. Secondary outcomes included the relationship between the gut microbiota and other factors, including diet, medication, inflammation, and pulmonary function in pwCF.

RESULTS

Thirty-eight studies were identified. The literature confirmed the presence of CF-related gut dysbiosis, characterized by reduced diversity and several taxonomic changes. There was a relative increase of bacteria associated with a pro-inflammatory response coupled with a reduction of those considered anti-inflammatory. However, studies linking gut dysbiosis to systemic and lung inflammation were limited. Causes of gut dysbiosis were multifactorial, and findings were variable. Data on the impact of CFTR modulators on the gut microbiota were limited.

CONCLUSIONS

CF-related gut dysbiosis is evident in pwCF. Whether this influences local and systemic disease and is amenable to interventions with diet and drugs, such as CFTR modulators, requires further investigation.

Standards of care for CFTR variant-specific therapy (including modulators) for people with cystic fibrosis

Cystic fibrosis (CF) has entered the era of variant-specific therapy, tailored to the genetic variants in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. CFTR modulators, the first variant-specific therapy available, have transformed the management of CF. The latest standards of care from the European CF Society (2018) did not include guidance on variant-specific therapy, as CFTR modulators were becoming established as a novel therapy. We have produced interim standards to guide healthcare professionals in the provision of variant-specific therapy for people with CF. Here we provide evidence-based guidance covering the spectrum of care, established using evidence from systematic reviews and expert opinion. Statements were reviewed by key stakeholders using Delphi methodology, with agreement (≥80%) achieved for all statements after one round of consultation. Issues around accessibility are discussed and there is clear consensus that all eligible people with CF should have access to variant-specific therapy.

Updates in Nutrition Management of Cystic Fibrosis in the Highly Effective Modulator Era

Attainment and maintenance of good nutrition has been an important aspect of management in cystic fibrosis (CF) for decades. In the era of highly effective modulator therapy for CF, the quality of the nutrients we recommend is increasingly important. Our therapy must support our patients' health for many years beyond what we previously thought. Preventing cardiovascular disease, reducing hyperlipidemia, and optimizing lean body mass for active, longer lives now join the long-standing goal of promoting lung function through nutrition. This chapter summarizes recent developments in nutrition in people with CF, with an eye to the evolution of our practice.