CF Patients Research Articles

Humoral and cell-mediated immune responses to BNT162b2 vaccine against SARS-CoV-2 in people with cystic fibrosis

People with cystic fibrosis (pwCF) were considered to be clinically vulnerable to COVID-19 and were therefore given priority in the vaccination campaign. Vaccines induced a humoral response in these patients that was comparable to the response observed among the general population. However, the role of the cell-mediated immune response in providing long-term protection against SARS-CoV-2 in pwCF has not yet been defined. In this study, humoral (antibody titre) and cell-mediated immune responses (interferon-γ release) to the BNT162b2 vaccine were measured at different time points, from around 6–8 months after the 2nd dose and up to 8 months after the 3rd dose, in 118 CF patients and 26 non-CF subjects. Subjects were sampled between November 2021 and September 2022 and followed-up for breakthrough infection through October 2022. pwCF mounted a cell-mediated response that was similar to that observed in non-CF subjects. Low antibody titres (<1st quartile) were associated with a higher risk of breakthrough infection (HR: 2.39, 95 % CI: 1.17–4.88), while there was no significant association with low INF-γ levels (<0.3 IU/mL) (HR: 1.38, 95 % CI: 0.64–2.99). Further studies are needed in subgroup of pwCF receiving immunosuppressive therapy, such as organ transplant recipients. This data is important for tailoring vaccination strategies for this clinically vulnerable population.

Therapeutic potential of phytochemicals for cystic fibrosis.

The aim of this review was to review and discuss various phytochemicals that exhibit beneficial effects on mutated membrane channels, and hence, improve transmembrane conductance. These therapeutic phytochemicals may have the potential to decrease mortality and morbidity of CF patients. Four databases were searched using keywords. Relevant studies were identified, and related articles were separated. Google Scholar, as well as gray literature (i.e., information that is not produced by commercial publishers), were also checked for related articles to locate/identify additional studies. The relevant databases were searched a second time to ensure that recent studies were included. In conclusion, while curcumin, genistein, and resveratrol have demonstrated effectiveness in this regard, it should be emphasized that coumarins, quercetin, and other herbal medicines also have beneficial effects on transporter function, transmembrane conductivity, and overall channel activity. Additional in vitro and in vivo studies should be conducted on mutant CFTR to unequivocally define the mechanism by which phytochemicalsalter transmembrane channel function/activity, since the results of the studies evaluated in this review have a high degree of heterogenicity and discrepancy. Finally, continued research be undertaken to clearly define the mechanism(s) of action and the therapeutic effects that therapeutic phytochemicals have on the symptoms observed in CF patients in an effort to reduce mortality and morbidity.

Applying patient personalized organoid model system to understand complex GI manifestations in cystic fibrosis disease

Background: Stem cell-derived organotypic culture has become a revolutionary tool in transforming care for patients with multiple GI-disorders. Cystic fibrosis is a deadly genetic disorder with multiple GI complications, such as Distal intestinal obstruction syndrome (DIOS), chronic constipation, Gastroesophageal reflux disease (GERD), and in some cases pancreatitis, caused by loss of function mutations in the gene that encodes for the cystic fibrosis transmembrane conductance regulator (CFTR) chloride/bicarbonate ion channel. Due to genetic and environmental influences, CF patients exhibit large phenotypic variation. These factors make clinical trials difficult and largely impractical due to limited and heterogenous patient pools, and additionally, the benefit of approved small-molecule CF therapy in a large number of rare mutation patients is not known. Moreover, critical questions of whether CFTR contributes to the development of intestine and how it contributes to GI-related issues remain unanswered. Results: In this study, we performed a comprehensive bench-side study using in vitro patient enteroids and in vivo mice implanted Human Intestinal Organoids (HIOs) to test highly effective CFTR modulators -Ivacaftor response for a rare CF mutation patient. Based on the positive Ivacaftor response in the enteroids, the patient was enrolled in N=1 clinical trial and showed improved GI outcomes upon Ivacaftor treatment. HIO implantation model allowed in vivo modulator dosing and provided an elegant human organ-based demonstration of bench-to-bedside testing of modulator effects. Additionally, using the CF HIO model the role of CFTR function in the maturation of human intestine was reported for the first time. In HIOs derived from a stop mutation CF patient and CFTR-corrected HIOs as control, we performed single cell RNAseq analysis to generate a molecular map of GI-cell type specific transcriptomic alterations and identify key targetable pathways relevant to stop mutations in CFTR for which currently there is no small molecule therapy. Conclusion: In all, we demonstrate that these models effectively serve to translate data from the lab to the clinic and back so that patient specific therapies could be validated, or new therapies be devised. Additionally, single-cell RNA sequencing in patient HIOs will provide useful insights into cell population specific and transcriptomic level alterations that are associated with abnormalities in GI function in CF. Nothing to disclose This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Variability of the sweat test in children with Cystic Fibrosis previously CRMS/CFSPID: A retrospective monocenter experience

Some studies have evaluated the sweat test (ST) intra individual variability in CRMS/CFSPID. Here, we retrospectively evaluated this in a cohort followed at the CF center in Florence, Italy. We enrolled 37 CRMS/CFSPID and 37 CF children, born between 2011 and 2019. A total of 327 ST were retrospectively recovered, of which 17 (5.2%) were quantity not sufficient. After a median follow-up of 33.8 months (range 1.7–88.2), 11 (24.3%) became CF with at least two pathological sweat chloride (SC) values at a median age of 46.9 months (range 1.4–49). The coefficient of variation was 6.2% in CF patients and 32.5% in the CRMS/CFSPID that transitioned to CF (P<.001). Our data highlight a more variability of SC values in CRMS/CFSPID, especially in those that transitioned to a diagnosis of CF. Further studies are needed to understand whether it is correct to define an asymptomatic CRMS/CFSPID with pathological SC as CF.

Correlation of Electrophysiological and Fluorescence-Based Measurements of Modulator Efficacy in Nasal Epithelial Cultures Derived from People with Cystic Fibrosis.

It has been suggested that in vitro studies of the rescue effect of CFTR modulator drugs in nasal epithelial cultures derived from people with cystic fibrosis have the potential to predict clinical responses to the same drugs. Hence, there is an interest in evaluating different methods for measuring in vitro modulator responses in patient-derived nasal cultures. Commonly, the functional response to CFTR modulator combinations in these cultures is assessed by bioelectric measurements, using the Ussing chamber. While this method is highly informative, it is time-consuming. A fluorescence-based, multi-transwell method for assaying regulated apical chloride conductance (Fl-ACC) promises to provide a complementary approach to theratyping in patient-derived nasal cultures. In the present work, we compared Ussing chamber measurements and fluorescence-based measurements of CFTR-mediated apical conductance in matching, fully differentiated nasal cultures derived from CF patients, homozygous for F508del (n = 31) or W1282X (n = 3), or heterozygous for Class III mutations G551D or G178R (n = 5). These cultures were obtained through a bioresource called the Cystic Fibrosis Canada-Sick Kids Program in Individual CF Therapy (CFIT). We found that the Fl-ACC method was effective in detecting positive responses to interventions for all genotypes. There was a correlation between patient-specific drug responses measured in cultures harbouring F508del, as measured using the Ussing chamber technique and the fluorescence-based assay (Fl-ACC). Finally, the fluorescence-based assay has the potential for greater sensitivity for detecting responses to pharmacological rescue strategies targeting W1282X.

Association of low-density neutrophils with lung function and disease progression in adult cystic fibrosis

BackgroundCystic fibrosis (CF) neutrophils fail to eradicate infection despite their massive recruitment into the lung. While studies mostly focus on pathogen clearance by normal density neutrophils in CF, the contribution of low-density neutrophil (LDNs) subpopulations to disease pathogenesis remains unclear. MethodsLDNs were isolated from whole blood donations of clinically stable adult CF patients and from healthy donors. LDN proportion and immunophenotype was assessed by flow cytometry. Associations of LDNs with clinical parameters were determined. ResultsLDN proportion was increased in CF patients’ circulation compared with healthy donors. LDNs are a heterogeneous population of both mature and immature cells in CF and in healthy individuals. Moreover, a higher proportion of mature LDN correlates with a gradual decline in lung function and repeated pulmonary exacerbations in CF patients. ConclusionsCollectively, our observations suggest that low-density neutrophils are linked to CF pathogenesis and underscore the potential clinical relevance of neutrophil subpopulations in CF.

A foetus with cystic fibrosis – To treat or not to treat?

BackgroundCystic fibrosis (CF) is an autosomal recessive health condition caused by gene mutations causing quantitative and or qualitative defect in the cystic-fibrosis transmembrane conductance regulator (CFTR) protein. CFTR defects lead to abnormal ion transport affecting multiple body systems. In CF thick secretions accumulate causing impairment in the pancreas, whole airways, gut and reproductive organs. CFTR modulators and pregnancyCFTR modulators have improved the quantity and quality of life of CF patients. There is limited literature on CFTR modulator use in pregnancy and its impact on foetal health. A recent case report described a child with CF being born with pancreatic sufficiency following in-utero CFTR modulator exposure. We review the potential impact of in-utero exposure to CFTR modulators, focusing on pancreatic function and future fertility of unborn individuals with CF. ConclusionCFTR modulator exposure in-utero is a new concept, therefore the consequences on foetal health remain uncertain. Foetal exposure to modulators could prevent pancreatic damage and infertility.

Intussusception of the appendix in a young adult: an important differential diagnosis of abdominal pain in cystic fibrosis patients?

Cystic fibrosis (CF) is commonly associated with gastrointestinal manifestations from infancy to adulthood. Distal intestinal obstruction syndrome (DIOS) affects 20% of CF patients, where intussusception can be a rare complication. A 20-year-old CF male was diagnosed with a 3-day history of right iliac fossa pain and diarrhoea. Clinical examination revealed a tender palpable mass in the right iliac fossa and raised serum inflammatory markers. Contrast computerized-tomography of the abdomen-pelvis suggested intussusception of the appendix and further confirmed on histological analyses. The patient underwent an open appendicectomy where the intussusception had self-resolved. The literature review indicated a scarcity of data with 10 cases reported of intussusception in adult CF patients. Our case was in line with previous research of transient intussusception. This rare case highlights an importance to carry a higher index of suspicion for gastrointestinal manifestations in CF patients where differential diagnoses of DIOS and intussusception should be considered in the acute presentation.

Association between Cystic Fibrosis exacerbations, lung function, T2 inflammation and microbiological colonization

BackgroundThe Cystic Fibrosis Foundation Patient Registry (CFFPR) reports a high prevalence of asthma (34.6%) in people with Cystic Fibrosis (PwCF). While our current understanding of this relationship is limited, a type 2 inflammatory (T2) phenotype has often been identified in CF patients.Research questionThis study aimed to evaluate the relationship between the eosinophilic CF T2 inflammatory phenotype and CF-related pulmonary outcomes and microbiological data.Study design and methodsWe conducted a retrospective chart review of adult patients with CF (18 and older; n = 93) receiving their care at University of Virginia Medical Center adult program from January, 2013 through December, 2018. Data collected included demographic data, CFTR (CF transmembrane conductance regulator) mutation, CF comorbidities, medications, Absolute Eosinophil Counts (AEC) in cells/µL and Immunoglobulin E (IgE) levels in IU/mL.ResultsOf 93 patients screened for study eligibility, 74 were included in the final analysis; 19 patients were excluded due to lack of longitudinal data across the study timeline. Lung function decline correlated with increased AEC (p < 0.001) and IgE (p < 0.001) even when adjusting for covariates: age, gender, presence of Pseudomonas spp., MRSA, other bacterial spp., Aspergillus spp., and other fungi (p < 0.001). Univariate analysis demonstrated that people with CF who experienced more than 2 exacerbations requiring hospitalizations and/or intravenous antibiotics a year were more likely to have high AEC (p = 0.018). Logistic regression showed that as AEC increases, the probability that the measurement was taken during a CF exacerbation increases (p = 0.0039). A linear mixed model showed that each additional annual exacerbation event increased on average the log IgE by 0.04. (p = 0.015). This finding remained stable in a multivariate model (p = 0.0145). When adjusted for atopy, log IgE increases as the number of exacerbation events increases (p = 0.022). There was no association between AEC and IgE and microbiological colonization.InterpretationThis study has shown that in CF patients, T2 inflammation based on serum AEC and IgE correlated with pulmonary exacerbations requiring hospitalizations and/or intravenous antibiotics, independent of bacterial airway colonization. In addition, lung function decline correlated with increased IgE and AEC. Further studies are needed to explore these correlations and potential impact on treatment.

Cystic Fibrosis Bone Disease: The Interplay between CFTR Dysfunction and Chronic Inflammation.

Cystic fibrosis is a monogenic disease with a multisystemic phenotype, ranging from predisposition to chronic lung infection and inflammation to reduced bone mass. The exact mechanisms unbalancing the maintenance of an optimal bone mass in cystic fibrosis patients remain unknown. Multiple factors may contribute to severe bone mass reduction that, in turn, have devastating consequences in the patients' quality of life and longevity. Here, we will review the existing evidence linking the CFTR dysfunction and cell-intrinsic bone defects. Additionally, we will also address how the proinflammatory environment due to CFTR dysfunction in immune cells and chronic infection impairs the maintenance of an adequate bone mass in CF patients.

Concomitant Use of Elexacaftor/Tezacaftor/Ivacaftor and Etanercept in a Cystic Fibrosis Patient with Juvenile Idiopathic Arthritis

Patients with cystic fibrosis often complain of joint manifestations. However, only a few studies have reported the association between cystic fibrosis and juvenile idiopathic arthritis and addressed the therapeutic challenges of these patients. We describe the first paediatric case of a patient affected by cystic fibrosis, Basedow's disease and juvenile idiopathic arthritis who was contemporarily treated with elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) and anti-tumor necrosis factor α (anti-TNFα). This report seems to reassure regarding the potential side effects of these associations. Moreover, our experience suggests that anti-TNFα is an effective option in CF patients affected by juvenile idiopathic arthritis, and is even safe for children receiving a triple CFTR modulator.

Study of human ribosomal gene complex in cystic fibrosis

Increasing the life expectancy of patients with CF is an urgent healthcare task all over the world. According to the Register of patients with cystic fibrosis in the Russian Federation (2020), the number of patients over 18 years of age is 26.5%. Assumably, cystic fibrosis can be used as a model of accelerated aging to study the aging process in general.Aim of the study was to analyze the number of rDNA copies in a sample of cystic fibrosis patients at different ages and with lethal outcome in relation to lung function, complications, and respiratory tract infections.Methods. We studied DNA samples isolated by the standard method from peripheral blood leukocytes of 277 patients diagnosed with cystic fibrosis. 998 DNA samples from healthy volunteers were used as a control group.Results. The study showed that the genomes of patients with CF contain more rDNA copies than those of control patients. The greatest number of copies of ribosomal genes was observed in DNA samples from deceased patients (p &lt; 0.001) and was associated with more severe disease course. Among all CF patients, the largest number of rDNA copies in the genome was registered in patients with the lowest FEV1 values (less than 40%). It was found that patients with chronic Burkholderia cepacia complex infection had a significantly higher number of copies of ribosomal repeats than the total sample (p = 0.001) and the adults (p = 0.014). The number of ribosomal repeats did not differ between patients with other chronic respiratory tract infections.Conclusion. In the group of deceased patients, the patients with low respiratory function and Burkholderia cepacia complex infection had the highest number of rDNA copies in the genome, and the differences were significant. It can be assumed that the number of rDNA copies in the genome of CF patients is an additional prognostic marker that is associated with the patient’s life expectancy.

Acute soluble fibre supplementation has no impact on reducing post-prandial glucose excursions in adults with cystic fibrosis and glucose intolerance

BackgroundCystic fibrosis (CF)-related diabetes (CFRD) is a common comorbidity in CF. In CFRD, fasting blood glucose level is often normal, but post-prandial glycaemia (PPG) is problematic. Elevated PPG has been associated to a higher risk of developing CFRD, a worst clinical state and a lower pulmonary function. Interventional studies in type 2 diabetes have demonstrated a beneficial impact of fibre supplement on PPG. MethodsOur objective is to evaluate the efficiency of 2 doses of a soluble fibre supplement to lower PPG in CF patients with glucose intolerance (pre-diabetic or CFRD patients). This is a double-blinded crossover interventional study with three interventions: placebo or psyllium fibre (5.1g or 7.7g) of soluble fibre consumed before breakfast. A second meal (lunch) is also eaten four hours later to evaluate a second meal effect. Blood glucose and insulin were measured during the interventions. ResultsIn 14 adult CF patients with impaired glucose tolerance (IGT; n=10) or CFRD (n=4), we observed no beneficial effect of fibre supplementation on PPG for both meals. However, all blood glucose levels were lower after the lunch compared to breakfast in spite of the higher carbohydrate content. ConclusionAn acute treatment with fibre supplementation had no effect on blood glucose control in patients with CF-IGT or CFRD.

Eosinophilic Cystic Fibrosis Is Associated with Increased Health Care Utilization

The Cystic Fibrosis Foundation Patient Registry (CFFPR) reports a high prevalence of asthma (34.6%) in people with Cystic Fibrosis (PwCF). While our current understanding of this relationship is limited, a type 2 inflammatory (T2) eosinophilic phenotype has often been identified in CF patients. This study aimed to evaluate the relationship between the eosinophilic CF T2 inflammatory phenotype and CF-related pulmonary outcomes and microbiological data.

Changes in Shear Wave Elastography after Lumacaftor/Ivacaftor Treatment in Children with Cystic Fibrosis.

Lumacaftor/Ivacaftor (LUM/IVA) is an approved combination therapy for cystic fibrosis (CF) patients homozygous for F508del. This study aimed to detect changes in liver stiffness measurement (LSM) in patients under this treatment. The study population consisted of CF patients homozygous for F508del, 6 to 11 years old, who had been treated for six months with LUM/IVA. Shear wave elastography (SWE) was performed in all of them, before and 6 months after the commencement of treatment. Thirty-one patients were included in the study. LSM values after treatment were significantly higher than the values before treatment (medians and interquartile ranges of LSM values before and after treatment: 5.6, 5.3-6.3 kPa and, 6.4, 6.0-7.6 kPa, respectively, p<0.001). SWE can detect early changes in LSM in some CF patients treated with LUM/IVA.

Changes in cystic fibrosis transmembrane conductance regulator protein expression prior to and during elexacaftor-tezacaftor-ivacaftor therapy.

Background: Defects in expression, maturation or function of the epithelial membrane glycoprotein CFTR are causative for the progressive disease cystic fibrosis. Recently, molecular therapeutics that improve CFTR maturation and functional defects have been approved. We aimed to verify whether we could detect an improvement of CFTR protein expression and maturation by triple therapy with elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA). Methods: Rectal suction biopsies of 21 p.Phe508del homozygous or compound heterozygous CF patients obtained pre- and during treatment with ELX/TEZ/IVA were analyzed by CFTR Western blot that was optimized to distinguish CFTR glycoisoforms. Findings: CFTR western immunoblot analysis revealed that-compared to baseline-the levels of CFTR protein increased by at least twofold in eight out of 12 patients upon treatment with ELX/TEZ/IVA compared to baseline (p < 0.02). However, polydispersity of the mutant CFTR protein was lower than that of the fully glycosylated wild type CFTR Golgi isoform, indicating an incompletely glycosylated p.Phe508el CFTR protein isoform C* in patients with CF which persists after ELX/TEZ/IVA treatment. Interpretation: Treatment with ELX/TEZ/IVA increased protein expression by facilitating the posttranslational processing of mutant CFTR but apparently did not succeed in generating the polydisperse spectrum of N-linked oligosaccharides that is characteristic for the wild type CFTR band C glycoisoform. Our results caution that the lower amounts or immature glycosylation of the C* glycoisoform observed in patients' biomaterial might not translate to fully restored function of mutant CFTR necessary for long-term provision of clinical benefit.

Lipidomic alterations in human saliva from cystic fibrosis patients

Cystic fibrosis is a hereditary metabolic disorder characterized by impaired traffic of chloride ions and water through membranes of the respiratory and gastrointestinal, that causes inadequate hydration of airway surfaces, dehydrated mucous secretions and a high-sodium chloride sweat. Although the classical presentation of the condition is well known, a better characterization of metabolic alterations related is need. In particular, the metabolic composition alterations of biological fluids may be influence by the disease state and could be captured as putative signature to set targeted therapeutic strategies. A targeted comprehensive mass spectrometry-based platform was employed to dissect the lipid content of saliva samples form CF patients, in order to investigate alterations in the lipid metabolic homeostasis related to the pathology, chronic obstructive pulmonary disease, Pseudomonas Aeruginosa infection, pancreatic insufficiency, liver disfunction and diabetes-related complications.

Quality of life assessment of adolescent and adult patients with cystic fibriosis (literature review)

Assessment of quality of life depending on the health of pediatric, adolescent and adult patients with cystic fibrosis allow to identify the main factors that influence the quality of their lives. Оne of the most common QoL questionnaires for cystic fibrosis patients is CFQ-R, that has proven its reliability and validity in different countries and in various clinical trials. The results of the trials demonstrated that the important prognostic factors were FEV1%, gender, BMI, age, and pulmonary exacerbations: FEV1 correlated with such score indicators as «physical functioning» (r=0.27–0.76), «health erception» (r=0.34–0.66), «respiratory symptoms» (r=0.36–0.47) and «bur-den of treatment» (r=0.26–0.39). Patients with LES P. aeruginosa epidemic strain had lower quality of life scores. Comparison of Hospital Anxiety and Depression Score (HADS) and CFQ-R domains (scores) showed that even in case of subclinical anxiety and depression (over 8 points according to HADS), the quality of life indicators were decreased, in particular in 9 out of 12 CFQ-R domains, especially for «emotional functioning» domain (p&lt;0.001).Female patients with cystic fibrosis had lower quality of life indicators compared to male patients, however, they had higher “body image” score. One study demon-strated that everyday physical activity promoted higher work engagement (р=0.024) and more positive attitude towards the future (р=0.032). Also, quality of life indicators were better for patients living in a family, and patients with higher social activity.Conclusion. Quality of life in CF patients is mainly under the influence of pulmonary function indicators, disease exacerbations, and anxiety and depression. For adult CF patients, family, professional and social aspects of life are highly critical. CFQ-R questionnaire for cystic fibrosis patients has proven its sensitivity and reliability.

Vitamin D levels and their association with oxidative stress and inflammation markers in patients with cystic fibrosis.

Introduction: cystic fibrosis is a disease that causes inflammation, oxidative stress and metabolic changes that lead to nutrient deficiency, such as vitamin D deficiency. On the other hand, it is suggested that vitamin D has anti-inflammatory and antioxidant actions. Objective: to evaluate the prevalence of hypovitaminosis D and the association between serum 25 hydroxyvitamin D levels with markers of oxidative stress and inflammation in patients with cystic fibrosis. Method: a cross-sectional study was carried out with 48 patients with cystic fibrosis including children, adolescents and adults in the northeast region of Brazil. Blood collection was performed for analysis of 25-hydroxyvitamin D, calcium, parathyroid hormone, inflammatory process (C-reactive protein (CRP) and alpha-1-acid glycoprotein-A1 (A1GPA)) and oxidative stress (malondialdehyde (MDA) and total antioxidant capacity (CAOT)). The statistical analysis was performed using the "Statistical Package for the Social Sciences", adopting a significance level of p < 0.05. Results: Vitamin D insufficiency/deficiency was found in 64.6 % of patients. After multiple linear regression analysis, MDA showed an inverse association with blood values of 25-Hydroxyvitamin D (p < 0.05) conditioned by the presence of inflammatory process markers. When only oxidative stress was evaluated, this association disappeared. Conclusion: in conclusion, there was a high prevalence of hypovitaminosis D, with 25(OH)D levels associated with greater oxidative stress when combined with inflammatory markers. Improved vitamin D levels may be an alternative to reduce the damage caused by excess oxidative stress and inflammation in CF patients.

Impaired distal colonic pH in adults with cystic fibrosis

Previous wireless motility capsule (WMC) studies demonstrated decreased small intestinal pH in people with CF (PwCF) however the data is lacking on the colonic pH profile. We re-analyzed previously published WMC data to determine colonic pH/bicarbonate concentration and single cell RNA sequencing (sc-RNAseq) to examine the normal expression of acid-base transporters in the colon/rectum.CF patients showed significantly lower pH and bicarbonate concentration values, particularly in the distal rectosigmoid region. There was no difference in colonic motility parameters between CF and non-CF subjects. SLC26A3 is highly expressed bicarbonate transporter in the colon and rectum, more so than CFTR. While dysmotility can alter intraluminal pH, observed changes likely originate from alterations in intestinal ion transport rather than colonic dysmotility. SLC26A3 is abundantly expressed in the human colon and rectum and may be a therapeutic target for restoration of bicarbonate transport. These findings may help better understand the gastrointestinal symptoms in PwCF