Evidence of intestinal inflammation in patients with cystic fibrosis

The epithelial barrier theory and its associated diseases

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, over 350,000 new chemical substances have been introduced to the lives of humans. In recent years, the epithelial barrier theory came to light explaining the growing prevalence and exacerbations of these diseases worldwide. It attributes their onset to a functionally impaired epithelial barrier triggered by the toxicity of the exposed substances, associated with microbial dysbiosis, immune system activation, and inflammation. Diseases encompassed by the epithelial barrier theory share common features such as an increased prevalence after the 1960s or 2000s that cannot (solely) be accounted for by the emergence of improved diagnostic methods. Other common traits include epithelial barrier defects, microbial dysbiosis with loss of commensals and colonization of opportunistic pathogens, and circulating inflammatory cells and cytokines. In addition, practically unrelated diseases that fulfill these criteria have started to emerge as multimorbidities during the last decades. Here, we provide a comprehensive overview of diseases encompassed by the epithelial barrier theory and discuss evidence and similarities for their epidemiology, genetic susceptibility, epithelial barrier dysfunction, microbial dysbiosis, and tissue inflammation.

The impact of a whole foods dietary intervention on gastrointestinal symptoms, inflammation, and fecal microbiota in pediatric patients with cystic fibrosis: A pilot study

BACKGROUND

Gastrointestinal (GI) complications are a significant source of morbidity for people with cystic fibrosis (PwCF). Historically, dietary recommendations in CF have focused on calories, typically emphasizing a high fat diet. The changing landscape of CF highlights the need to update this nutritional strategy. There is little research into how the quality of calories consumed by PwCF influences nutritional outcomes, GI symptoms, or likely contributors: intestinal inflammation and GI microbiology. We assessed the feasibility of a whole foods-based diet (WFD) and avoidance of ultra-processed foods, measuring safety/tolerability, adherence, and GI symptoms, as well as fecal measures of inflammation and microbiota among children with CF (CwCF) with GI symptoms.

METHODS

Single center, 4-week dietary intervention involving CwCF aged 5-14 years who screened positive on GI symptom questionnaire. Assessments included weight, symptom questionnaires and adverse events (AEs). Stool was analyzed for microbiota (16S rRNA) and calprotectin.

RESULTS

108 children were pre-screened, 9 enrolled and 8 initiated and completed the study. There were no significant changes in weight and no AEs. PEDS-QL GI identified overall improvement in symptoms. Certain symptom domains (constipation, diarrhea, gas/bloating, stomach pain and hurt) demonstrated significant improvement on the WFD. Of two participants with abnormal fecal calprotectin at enrollment, both exhibited decreased values on WFD. There was no significant change in microbiota diversity.

CONCLUSION

A WFD diet was feasible and safe in CwCF. There was improvement in GI symptom scores based on both parent and child assessments. Larger studies are needed to further investigate effects on intestinal inflammation and microbiota.

Gastrointestinal Cancers in Hospitalized Patients with Cystic Fibrosis: A Nationwide Study, 2010-2020

BACKGROUND

As life expectancy in cystic fibrosis (CF) patients has increased, so has the incidence of cancers. We aimed to investigate and describe gastrointestinal cancers in CF hospitalized patients from 2010 to 2020.

METHODS

Utilizing the National Inpatient Sample, we extracted cases of CF-associated hospitalizations and gastrointestinal cancers as well as demographic and clinical data. We compared our CF cohort to age, sex, and race/ethnicity-matched controls. Trends were analyzed by Poisson regression.

RESULTS

We identified a total of 902 hospitalizations of CF with gastrointestinal cancer; among them, 539 (59.8%) were colorectal, 139 (15.4%) were liver, 105 (11.6%) were pancreatic, 54 (6.0%) were small bowel, 35 (3.9%) were gastric, and 30 (3.3%) were esophageal cancers. The median age of hospitalization for gastrointestinal cancers ranged from 39 years in liver cancer to 65 years in small bowel cancer. Mortality ranged from 9.5% in pancreatic to 0.0% in small bowel cancer. Colorectal cancer (IRR: 1.09; p = 0.005), pancreatic cancer (IRR: 1.17; p = 0.023), gastric cancer (IRR: 1.41; p = 0.003), and esophageal cancer (IRR: 1.50; p = 0.023) hospitalization rates have been increasing over time. Rates of colorectal (p = 0.037) cancer were significantly higher in our CF cohort compared to controls.

CONCLUSIONS

Colorectal cancers are the major gastrointestinal cancers in CF patients, and the incidence of these hospitalizations is increasing.

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.

Fecal calprotectin in pediatric gastrointestinal diseases: Pros and cons

BACKGROUND

Fecal calprotectin is a valuable biomarker for assessing intestinal inflammation in pediatric gastrointestinal diseases. However, its role, pros, and cons in various conditions must be comprehensively elucidated.

AIM

To explore the role of fecal calprotectin in pediatric gastrointestinal diseases, including its advantages and limitations.

METHODS

A comprehensive search was conducted on PubMed, PubMed Central, Google Scholar, and other scientific research engines until February 24, 2024. The review included 88 research articles, 56 review articles, six meta-analyses, two systematic reviews, two consensus papers, and two letters to the editors.

RESULTS

Fecal calprotectin is a non-invasive marker for detecting intestinal inflammation and monitoring disease activity in pediatric conditions such as functional gastrointestinal disorders, inflammatory bowel disease, coeliac disease, coronavirus disease 2019-induced gastrointestinal disorders, gastroenteritis, and cystic fibrosis-associated intestinal pathology. However, its lack of specificity and susceptibility to various confounding factors pose challenges in interpretation. Despite these limitations, fecal calprotectin offers significant advantages in diagnosing, monitoring, and managing pediatric gastrointestinal diseases.

CONCLUSION

Fecal calprotectin holds promise as a valuable tool in pediatric gastroenterology, offering insights into disease activity, treatment response, and prognosis. Standardized protocols and guidelines are needed to optimize its clinical utility and mitigate interpretation challenges. Further research is warranted to address the identified limitations and enhance our understanding of fecal calprotectin in pediatric gastrointestinal diseases.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

EVALUATING LACTOFERRIN AND CALPROTECTIN AS MARKERS OF INTESTINAL INFLAMMATION INCHRONIC PANCREATITIS

BACKGROUND

The treatment of chronic pancreatitis does not consistently solve intestinal abnormalities, and despite the implementation of various therapeutic measures, patients often continue to experience persistent diarrhea. Therefore, it is imperative to recognize that diarrhea may stem from factors beyond pancreatic insufficiency, and intestinal inflammation emerges as a potential contributing factor.

OBJECTIVE

The aim of this study was to assess fecal lactoferrin and calprotectin levels as indicators of intestinal inflammation in patients with chronic pancreatitis experiencing persistent diarrhea.

METHODS

In this study, 23 male patients with chronic pancreatitis primarily attributed to alcohol consumption and presenting with diarrhea (classified as Bristol stool scale type 6 or 7), underwent a comprehensive evaluation of their clinical and nutritional status. Fecal lactoferrin and calprotectin levels were mea-sured utilizing immunoassay techniques.

RESULTS

The average age of the participants was 54.8 years, 43.5% had diabetes, and 73.9% were smokers. Despite receiving enzyme replacement therapy and refraining from alcohol for over 4 years, all participants exhibited persistent diarrhea, accompanied by elevated calprotectin and lactoferrin levels indicative of ongoing intestinal inflammation.

CONCLUSION

The findings of this study underscore that intestinal inflammation, as evidenced by elevated fecal biomarkers calprotectin and lactoferrin, may contribute to explaining the persistence of diarrhea in patients with chronic pancreatitis.

BACKGROUND

• Exploration of intestinal inflammation in chronic pancreatitis patients with altered bowel habits.

BACKGROUND

• Assessment of 23 patients using lactoferrin and calprotectin as intestinal inflammation biomarkers.

BACKGROUND

• Intestinal inflammation was detected in all patients; positive correlation between both biomarkers.

BACKGROUND

• Established connection between altered bowel habits and intestinal inflammation in chronic pancreatitis.

Fecal dysbiosis and inflammation in intestinal-specific Cftr knockout mice on regimens preventing intestinal obstruction

Chronic intestinal inflammation is a poorly understood manifestation of cystic fibrosis (CF), which may be refractory to ion channel CF transmembrane conductance regulator (CFTR) modulator therapy. People with CF exhibit intestinal dysbiosis, which has the potential for stimulating intestinal and systemic inflammation. CFTR is expressed in organ epithelia, leukocytes, and other tissues. Here, we investigate the contribution of intestinal epithelium-specific loss of Cftr [iCftr knockout (KO)] to dysbiosis and inflammation in mice treated with either of two antiobstructive dietary regimens necessary to maintain CF mouse models [polyethylene glycol (PEG) laxative or a liquid diet (LiqD)]. Feces collected from iCftr KO mice and their wild-type (WT) sex-matched littermates were used to measure fecal calprotectin to evaluate inflammation and to perform 16S rRNA sequencing to characterize the gut microbiome. Fecal calprotectin was elevated in iCftr KO relative to WT mice that consumed either PEG or LiqD. PEG iCftr KO mice did not show a change in α diversity versus WT mice but demonstrated a significant difference in microbial composition (β diversity) with included increases in the phylum Proteobacteria, the family Peptostreptococcaceae, four genera of Clostridia including C. innocuum, and the mucolytic genus Akkermansia. Fecal microbiome analysis of LiqD-fed iCftr KO mice showed both decreased α diversity and differences in microbial composition with increases in the Proteobacteria family Enterobacteriaceae, Firmicutes families Clostridiaceae and Peptostreptococcaceae, and enrichment of Clostridium perfringens, C. innocuum, C. difficile, mucolytic Ruminococcus gnavus, and reduction of Akkermansia. It was concluded that epithelium-specific loss of Cftr is a major driver of CF intestinal dysbiosis and inflammation with significant similarities to previous studies of pan Cftr KO mice.NEW & NOTEWORTHY Chronic intestinal inflammation is a manifestation of cystic fibrosis (CF), a disease caused by loss of the anion channel CF transmembrane conductance regulator (CFTR) that is expressed in many tissues. This study shows that intestinal epithelial cell-specific loss of CFTR [inducible Cftr knockout (KO)] in mice is sufficient to induce intestinal dysbiosis and inflammation. Experiments were performed on mice consuming two dietary regimens routinely used to prevent obstruction in CF mice.

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.

Autoimmunity in people with cystic fibrosis

Cystic fibrosis (CF) clinicians may see patients who have difficult-to-manage symptoms that do not have a clear CF-related etiology, such as unusual gastrointestinal (GI) complaints, vasculitis, or arthritis. Alterations in immunity, inflammation and intraluminal dysbiosis create a milieu that may lead to autoimmunity, and the CF transmembrane regulator protein may have a direct role as well. While autoantibodies and other autoimmune markers may develop, these may or may not lead to organ involvement, therefore they are helpful but not sufficient to establish an autoimmune diagnosis. Autoimmune involvement of the GI tract is the best-established association. Next steps to understand autoimmunity in CF should include a more in-depth assessment of the community perspective on its impact. In addition, bringing together specialists in various fields including, but not limited to, pulmonology, gastroenterology, immunology, and rheumatology, would lead to cross-dissemination and help define the path forward in basic science and clinical practice.

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.

Fecal Dysbiosis and Inflammation in Intestinal-Specific Cftr Knockout Mice on Regimens Preventing Intestinal Obstruction

Chronic intestinal inflammation is a poorly understood manifestation of Cystic Fibrosis (CF), which may be refractory to ion channel CFTR modulator therapy. People with CF exhibit intestinal dysbiosis which has potential for stimulating intestinal and systemic inflammation. CFTR is expressed in organ epithelia and in the leukocyte population. Here, we investigate the contribution of intestinal epithelial-specific loss of Cftr (iCftr KO) to dysbiosis and inflammation in mice treated with either of two anti-obstructive dietary regimens necessary to maintain CF mouse models (PEG laxative or a liquid diet, LiqD). Feces collected from iCftr KO mice and their wildtype (WT) sex-matched littermates were used to measure fecal calprotectin and to perform 16S rRNA sequencing to characterize the gut microbiome. Fecal calprotectin was elevated in iCftr KO relative to WT samples of mice consuming either PEG or LiqD. PEG iCftr KO mice did not show a change in α-diversity versus WT but demonstrated a significant difference in microbial composition (β-diversity) with increases in phylum Proteobacteria , family Peptostreptococcaceae , four genera of Clostridia including C. innocuum , and mucolytic genus Akkermansia . Fecal microbiome analysis of LiqD iCftr KO mice showed both decreased α-diversity and differences in microbial composition with increases in Proteobacteria family Enterobacteriaceae , Firmicutes families Clostridiaceae and Peptostreptococcaceae , and enrichment of Clostridium perfringens , C. innocuum , C. difficile , mucolytic Ruminococcus gnavus , and reduction of Akkermansia . It was concluded that epithelial-specific loss of Cftr is a major driver of CF intestinal dysbiosis and inflammation with significant similarities to previous studies of global Cftr KO mice.

New and noteworthy

Chronic intestinal inflammation is a manifestation of cystic fibrosis (CF), a disease caused by loss of the anion channel CFTR that is expressed in many tissues. This study shows that intestinal epithelial cell-specific loss of CFTR (iCftr KO) in mice is sufficient to induce intestinal dysbiosis and inflammation. Studies were performed on mice consuming either dietary regimen (PEG laxative or liquid diet) routinely used to prevent obstruction in CF mice.

Gut Dysbiosis in Children with Cystic Fibrosis: Development, Features and the Role of Gut-Lung Axis on Disease Progression

Cystic fibrosis (CF) is the most common autosomal recessive disease among Caucasians. Over the last 20 years, culture-independent analysis, including next-generation sequencing, has paired with culture-based microbiology, offering deeper insight into CF lung and gut microbiota. The aim of this review is to analyse the features of gut microbiota in patients with CF and its possible role in the progression of the disease, establishing the basis for a potential role in microbe-based therapies. The literature analysis showed that the gut environment in CF patients has unique features due to the characteristics of the disease, such as decreased bicarbonate secretion, increased luminal viscosity, and an acidic small intestinal environment, which, due to the treatment, includes regular antibiotic use or a high-energy and fat-dense diet. As a result, the gut microbial composition appears altered, with reduced richness and diversity. Moreover, the population of pro-inflammatory bacteria is higher, while immunomodulatory genera, such as Bacteroides and Bifidobacterium, are scarcer. The imbalanced gut microbial population has a potential role in the development of systemic inflammation and may influence clinical outcomes, such as respiratory exacerbations, spirometry results, and overall growth. Although a better understanding of the pathophysiology behind the gut-lung axis is needed, these findings support the rationale for considering gut microbiota manipulation as a possible intervention to regulate the severity and progression of the disease.

The association of fecal calprotectin and respiratory exacerbation in cystic fibrosis patients

Background

CF patients experience several episodes of pulmonary exacerbations and reduction in their lung function progressively. Lung function is not the only diagnostic index by physicians to decide if CF patients require antibiotic therapy following pulmonary exacerbations. Non-invasive fecal indicators are increasingly being used to assess intestinal inflammation. Calprotectin is the most extensively utilized fecal biomarker in recent CF researches.

Methods

In this longitudinal study, 30 CF patients (1–18 years) without current infectious gastroenteritis were recruited from Mofid Children's Hospital and Masih Daneshvari Hospital, Tehran, Iran. Then, fecal calprotectin levels were evaluated before treatment, two weeks after systemic antibiotic administration, as well as recurrence of pulmonary exacerbation after first post-hospital discharge.

Results

The initial fecal calprotectin level in CF patients receiving antibiotics was 651.13 ± 671.04, significantly decreasing two weeks after antibiotic therapy and following recurrence (171.81 ± 224.40, 607.93 ± 549.89, respectively; P < 0.01). Following systemic antibiotic treatment, the patient's respiratory and GI symptoms improved (P < 0.01).

Conclusion

Our findings revealed that fecal calprotectin modifications are associated with CF pulmonary exacerbations and antibiotic treatment could reduce calprotectin levels. Therefore, the fecal calprotectin level could be considered as a diagnostic tool and an index to follow the response to treatment in CF pulmonary exacerbations.

Nutritional and metabolic management for cystic fibrosis in a post-cystic fibrosis transmembrane conductance modulator era

PURPOSE OF REVIEW

The introduction of highly effective cystic fibrosis transmembrane conductance regulator modulators has resulted in a paradigm shift towards treating underlying cause of cystic fibrosis (CF) rather than the ensuing complications. In this review, we will describe the impact of these small molecules on growth, nutrition, and metabolic status in people with CF (pwCF).

RECENT FINDING

Results of clinical trials and real world data demonstrate that these small molecules are having a significant impact of on augmenting body weight, improving nutritional status and reducing gastrointestinal symptom burden. Early treatment can also positively impact on pancreatic endocrine and exocrine function.

SUMMARY

Nutritional and metabolic management of pwCF needs to change in order to maximize long term health and avoid future complications relating to obesity and increased cardiovascular risk. Longitudinal registry studies will be key to improve our understanding of the longer-term outcome of these new therapies.

Cftr deletion in mouse epithelial and immune cells differentially influence the intestinal microbiota

Cystic fibrosis (CF) is a life-threatening genetic disorder, caused by mutations in the CF transmembrane-conductance regulator gene (cftr) that encodes CFTR, a cAMP-activated chloride and bicarbonate channel. Clinically, CF lung disease dominates the adult patient population. However, its gastrointestinal illness claims the early morbidity and mortality, manifesting as intestinal dysbiosis, inflammation and obstruction. As CF is widely accepted as a disease of epithelial dysfunction, it is unknown whether CFTR loss-of-function in immune cells contributes to these clinical outcomes. Using cftr genetic knockout and bone marrow transplantation mouse models, we performed 16S rRNA gene sequencing of the intestinal microbes. Here we show that cftr deletion in both epithelial and immune cells collectively influence the intestinal microbiota. However, the immune defect is a major factor determining the dysbiosis in the small intestine, while the epithelial defect largely influences that in the large intestine. This finding revises the current concept by suggesting that CF epithelial defect and immune defect play differential roles in CF intestinal disease.

Body mass index and additional risk factors for cancer in adults with cystic fibrosis

BACKGROUND

Adults with cystic fibrosis (CF) have an increased risk of a variety of cancers, notably gastrointestinal cancers. In CF higher body mass index (BMI) is associated with improved long-term outcomes, yet in the general population high BMI is associated with increased cancer risk. We aimed to delineate associations between BMI and other factors with cancer risk in adults with CF.

METHODS

This was a retrospective cohort study using CF Foundation Patient Registry data from 1992 to 2015. Data were collected on age, sex, CFTR mutation class, pancreatic insufficiency, and annualized data on BMI and FEV1. The primary analysis was the association between BMI and cancer, with secondary analyses focused on BMI trajectory. Multivariable logistic regression was performed, with analyses stratified by history of transplant.

RESULTS

Of 26,199 adults with CF, 446 (1.7%) had cancer diagnosed by histology at a mean age of 40.0 years (SD 12.2), with a higher proportion of transplanted patients developing cancer (137 (3.8%) v 309(1.4%), p < 0.001). Among non-transplanted patients, there was no association between BMI and cancer (p for trend = 0.43). Pancreatic insufficiency (p < 0.01) and higher FEV1 (p < 0.01) were associated with increased cancer risk. In transplanted patients, higher BMI was associated with reduced risk of cancer (p for trend = 0.04). Older age was associated with increased risk in both groups (p < 0.001). BMI trajectories were not associated with cancer risk in either group.

CONCLUSION

Higher BMI is associated with a reduced risk of cancer in transplanted adults with CF. Pancreatic insufficiency is a risk factor for cancer in non-transplanted CF patients.

The NHE3 Inhibitor Tenapanor Prevents Intestinal Obstructions in CFTR-Deleted Mice

Mutations in the CFTR chloride channel result in intestinal obstructive episodes in cystic fibrosis (CF) patients and in CF animal models. In this study, we explored the possibility of reducing the frequency of obstructive episodes in cftr^−/− mice through the oral application of a gut-selective NHE3 inhibitor tenapanor and searched for the underlying mechanisms involved. Sex- and age-matched cftr^+/+ and cftr^−/− mice were orally gavaged twice daily with 30 mg kg⁻¹ tenapanor or vehicle for a period of 21 days. Body weight and stool water content was assessed daily and gastrointestinal transit time (GTT) once weekly. The mice were sacrificed when an intestinal obstruction was suspected or after 21 days, and stool and tissues were collected for further analysis. Twenty-one day tenapanor application resulted in a significant increase in stool water content and stool alkalinity and a significant decrease in GTT in cftr^+/+ and cftr^−/− mice. Tenapanor significantly reduced obstructive episodes to 8% compared to 46% in vehicle-treated cftr^−/− mice and prevented mucosal inflammation. A decrease in cryptal hyperproliferation, mucus accumulation, and mucosal mast cell number was also observed in tenapanor- compared to vehicle-treated, unobstructed cftr^−/− mice. Overall, oral tenapanor application prevented obstructive episodes in CFTR-deficient mice and was safe in cftr^+/+ and cftr^−/− mice. These results suggest that tenapanor may be a safe and affordable adjunctive therapy in cystic fibrosis patients to alleviate constipation and prevent recurrent DIOS.

Probiotics Administration in Cystic Fibrosis: What Is the Evidence?

In the last 20 years, gut microbiota in patients with cystic fibrosis (CF) has become an object of interest. It was shown that these patients had gut dysbiosis and this could explain not only the intestinal manifestations of the disease but also part of those involving the respiratory tract. The acquisition of previously unknown information about the importance of some bacteria, i.e., those partially or totally disappeared in the gut of CF patients, in the regulation of the activity and function of the gut and the lung was the base to suggest the use of probiotics in CF patients. The main aim of this paper is to discuss the biological basis for probiotic administration to CF patients and which results could be expected. Literature analysis showed that CF intestinal dysbiosis depends on the same genetic mutations that condition the clinical picture of the diseases and is aggravated by a series of therapeutic interventions, such as dietary modifications, the use of antibiotics, and the administration of antacids. All this translates into a significant worsening of the structure and function of organs, including the lung and intestine, already deeply penalized by the genetic alterations of CF. Probiotics can intervene on dysbiosis, reducing the negative effects derived from it. However, the available data cannot be considered sufficient to indicate that these bacteria are essential elements of CF therapy. Further studies that take into account the still unsolved aspects on how to use probiotics are absolutely necessary.

Children With Cystic Fibrosis Have Elevated Levels of Fecal Chitinase-3-like-1

Although chitinase-3-like-1 (CHI3L1), predominately produced by epithelial cells and macrophages, is relevant to pulmonary disease in cystic fibrosis (CF), fecal levels have not yet been assessed in children with CF. Fecal CHI3L1 was measured with a commercial immunoassay using fecal samples provided by children with CF and healthy control (HC) children. Higher median (interquartile range) fecal CHI3L1 levels were seen in the 52 children with CF than in the 35 controls: 15.97 (3.34-50.53) ng/g versus 2.93 (2.13-9.27) ng/g ( P = 0.001). Fecal CHI3LI did not differ according to sex. In the children with CF, fecal CHI3L1 levels did not correlate with growth parameters nor were the levels affected by pancreatic insufficiency. Children with CF had higher fecal CHI3L1 levels, suggesting underlying gut inflammation. Further work is required to confirm the current findings and to ascertain the longer-term significance of elevated CHI3L1.

Modulation, microbiota and inflammation in the adult CF gut: A prospective study

BACKGROUND

Cystic Fibrosis (CF) has prominent gastrointestinal and pancreatic manifestations. The aim of this study was to determine the effect of Cystic fibrosis transmembrane conductance regulator (CFTR) modulation on, gastrointestinal inflammation, pancreatic function and gut microbiota composition in people with cystic fibrosis (CF) and the G551D-CFTR mutation.

METHODS

Fourteen adult patients with the G551D-CFTR mutation were assessed clinically at baseline and for up to 1 year after treatment with ivacaftor. The change in gut inflammatory markers (calprotectin and lactoferrin), exocrine pancreatic status and gut microbiota composition and structure were assessed in stool samples.

RESULTS

There was no significant change in faecal calprotectin nor lactoferrin in patients with treatment while all patients remained severely pancreatic insufficient. There was no significant change in gut microbiota diversity and richness following treatment.

CONCLUSION

There was no significant change in gut inflammation after partial restoration of CFTR function with ivacaftor, suggesting that excess gut inflammation in CF is multi-factorial in aetiology. In this adult cohort, exocrine pancreatic function was irreversibly lost. Longer term follow-up may reveal more dynamic changes in the gut microbiota and possible restoration of CFTR function.

Neutrophil dysfunction in the pathogenesis of cystic fibrosis

Polymorphonuclear neutrophils (PMNs) figure prominently in host defense against infection and in noninfectious inflammation. Mobilized early in an inflammatory response, PMNs mediate immediate cellular defense against microbes and orchestrate events that culminate in cessation of inflammation and restoration of homeostasis. Failure to terminate the inflammatory response and its causes can fuel exuberant inflammation characteristic of many human diseases, including cystic fibrosis (CF), an autosomal recessive genetic disease caused by mutations in the CF transmembrane conductance regulator. CF affects multiple end organs, with persistent bacterial infection and chronic neutrophilic inflammation in airways predominating the clinical picture. To match the diverse microbial challenges that they may encounter, PMNs possess a variety of antimicrobial systems to slow or kill invading microorganisms confined in their phagosomes. Prominent among PMN defense systems is their ability to generate hypochlorous acid, a potent microbicide, by reacting oxidants generated by the NADPH oxidase with myeloperoxidase (MPO) released from azurophilic granules in the presence of chloride (Cl-). Products of the MPO-H2O2-Cl system oxidize susceptible biomolecules and support robust antimicrobial action against many, but not all, potential human pathogens. Underscoring that the MPO-H2O2-Cl system is integral to optimal host defense and proper regulation of inflammation, individuals with defects in any component of this system, as seen in chronic granulomatous disease or MPO deficiency, incur increased rates or severity of infection and signs of dysregulated inflammatory responses. We focus attention in this review on the molecular basis for and the clinical consequences of defects in the MPO-H2O2-Cl system because of the compromised Cl transport seen in CF. We will discuss first how the MPO-H2O2-Cl system in healthy PMNs participates in host defense and resolution of inflammation and then review how a defective MPO-H2O2-Cl system contributes to the increased susceptibility to infection and dysregulated inflammation associated with the clinical manifestations of CF.

Alterations of mucosa-attached microbiome and epithelial cell numbers in the cystic fibrosis small intestine with implications for intestinal disease

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Defective CFTR leads to accumulation of dehydrated viscous mucus within the small intestine, luminal acidification and altered intestinal motility, resulting in blockage. These changes promote gut microbial dysbiosis, adversely influencing the normal proliferation and differentiation of intestinal epithelial cells. Using Illumina 16S rRNA gene sequencing and immunohistochemistry, we assessed changes in mucosa-attached microbiome and epithelial cell profile in the small intestine of CF mice and a CF patient compared to wild-type mice and non-CF humans. We found increased abundance of pro-inflammatory Escherichia and depletion of beneficial secondary bile-acid producing bacteria in the ileal mucosa-attached microbiome of CFTR-null mice. The ileal mucosa in a CF patient was dominated by a non-aeruginosa Pseudomonas species and lacked numerous beneficial anti-inflammatory and short-chain fatty acid-producing bacteria. In the ileum of both CF mice and a CF patient, the number of absorptive enterocytes, Paneth and glucagon-like peptide 1 and 2 secreting L-type enteroendocrine cells were decreased, whereas stem and goblet cell numbers were increased. These changes in mucosa-attached microbiome and epithelial cell profile suggest that microbiota-host interactions may contribute to intestinal CF disease development with implications for therapy.

Faecal calprotectin and rectal histological inflammatory markers in cystic fibrosis: a single-centre study

OBJECTIVE

To analyse the association of faecal calprotectin with the genetic and clinical characteristics of paediatric patients with cystic fibrosis (PwCF). In a subset of these patients, we aimed to associate histological inflammatory features of rectal mucosa to faecal calprotectin levels.

METHODS

In a prospective study, faecal calprotectin levels were collected in all 23 PwCF attending our paediatric centre, together with demographic and clinical data. Associations between faecal calprotectin and clinical features were determined. In 11 of these patients, endoscopic rectal biopsies were obtained and the association between faecal calprotectin and histological inflammatory markers was analysed. Statistical analyses included Spearman's correlation coefficient, Mann-Whitney U test and Fisher's exact test. Sensitivity and specificity was calculated.

RESULTS

Median age of PwCF was 12 years, 19 had pancreatic insufficiency (PI) (19/23). Seventeen (17/23) had elevated faecal calprotectin, and the median value was 88 µg/g (IQR=178 µg/g). Higher faecal calprotectin levels were observed in the PI group (101 vs 30 µg/g, p=0.027). No significant correlation between elevated faecal calprotectin level and body mass index z-score was found. Five patients (22%) reported abdominal pain, three (13%) complained of diarrhoea and three (13%) had constipation, but these symptoms were not associated with elevated faecal calprotectin.Unspecific focal rectal inflammation was found in four patients (4/11). An association between rectal mucosa inflammation and elevated faecal calprotectin was found (p=0.015). Sensitivity was 100% and specificity was 86%.

CONCLUSIONS

In our PwCF, elevated faecal calprotectin was frequent, particularly if PI, and it was not related to gastrointestinal symptoms or malnutrition. Elevated faecal calprotectin was present in patients with histological evidence of rectal inflammation. Faecal calprotectin may be an indicator of asymptomatic rectal inflammation in PwCF.

Abdominal Symptoms Assessed With the CFAbd-Score are Associated With Intestinal Inflammation in Patients With Cystic Fibrosis

OBJECTIVES

This prospective study evaluated the relationship between fecal markers of intestinal inflammation and cystic fibrosis (CF)-associated abdominal symptoms. These were assessed using the CFAbd-Score, a CF-specific patient-related outcome measure developed and validated, following FDA guidelines.

METHODS

In feces from patients with CF (n = 41) and healthy volunteers (n = 27), concentrations of fecal calprotectin (FC), M2-pyruvate kinase (M2-PK), interleukins IL-1β, IL-6, IL-8, and neutrophilic elastase (NE) were measured. Abdominal symptoms during the 2 preceding weeks were recorded using the CFAbd-Score. This patient-reported outcome measure (PROM) for assessment of the multi-organic abdominal involvement in CF includes 28 items in five domains.

RESULTS

Inflammatory parameters FC, IL-1β, M2-PK, and NE in feces, as well as CFAbd-Scores resulted significantly higher in CF patients than in healthy controls (all P < 0.01). Furthermore, significant differences between both groups were found for pain-symptoms, disorders of bowel movement, impaired quality of life, as well as disorders of eating and appetite. With 83% sensitivity and 74% specificity, FC was the most reliable measure for CF-related intestinal inflammation, which, in the CFAbd-Score, was associated to significantly higher rates of abdominal pain, as well as to general quality of life items such as gastrointestinal-related impaired sleep and frustration.

CONCLUSION

Using the CFAbd-Score as a CF-specific PROM for identification and quantification of abdominal symptoms revealed that abdominal pain and impaired quality of life are associated with intestinal inflammation in CF.

Cystic fibrosis-related liver disease: Clinical presentations, diagnostic and monitoring approaches in the era of CFTR modulator therapies

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population. Cystic fibrosis-related liver disease (CFLD) is defined as the pathogenesis related to the underlying CFTR defect in biliary epithelial cells. CFLD needs to be distinguished from other liver manifestations that may not have any pathological significance. The clinical/histological presentation and severity of CFLD vary. The main histological presentation of CFLD is focal biliary fibrosis, which is usually asymptomatic. Portal hypertension develops in a minority of cases (about 10%) and may require specific management including liver transplantation for end-stage liver disease. Portal hypertension is usually the result of the progression of focal biliary fibrosis to multilobular cirrhosis during childhood. Nevertheless, non-cirrhotic portal hypertension as a result of porto-sinusoidal vascular disease is now identified increasingly more frequently, mainly in young adults. To evaluate the effect of new CFTR modulator therapies on the liver, the spectrum of hepatobiliary involvement must first be precisely classified. This paper discusses the phenotypic features of CFLD, its underlying physiopathology and relevant diagnostic and follow-up approaches, with a special focus on imaging.

Intestinal Inflammation and Alterations in the Gut Microbiota in Cystic Fibrosis: A Review of the Current Evidence, Pathophysiology and Future Directions

Cystic fibrosis (CF) is a life-limiting autosomal recessive multisystem disease. While its burden of morbidity and mortality is classically associated with pulmonary disease, CF also profoundly affects the gastrointestinal (GI) tract. Chronic low-grade inflammation and alterations to the gut microbiota are hallmarks of the CF intestine. The etiology of these manifestations is likely multifactorial, resulting from cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction, a high-fat CF diet, and the use of antibiotics. There may also be a bidirectional pathophysiological link between intestinal inflammation and changes to the gut microbiome. Additionally, a growing body of evidence suggests that these GI manifestations may have significant clinical associations with growth and nutrition, quality of life, and respiratory function in CF. As such, the potential utility of GI therapies and long-term GI outcomes are areas of interest in CF. Further research involving microbial modulation and multi-omics techniques may reveal novel insights. This article provides an overview of the current evidence, pathophysiology, and future research and therapeutic considerations pertaining to intestinal inflammation and alterations in the gut microbiota in CF.

What Do We Know about the Microbiome in Cystic Fibrosis? Is There a Role for Probiotics and Prebiotics?

Cystic fibrosis (CF) is a life-shortening genetic disorder that affects the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In the gastrointestinal (GI) tract, CFTR dysfunction results in low intestinal pH, thick and inspissated mucus, a lack of endogenous pancreatic enzymes, and reduced motility. These mechanisms, combined with antibiotic therapies, drive GI inflammation and significant alteration of the GI microbiota (dysbiosis). Dysbiosis and inflammation are key factors in systemic inflammation and GI complications including malignancy. The following review examines the potential for probiotic and prebiotic therapies to provide clinical benefits through modulation of the microbiome. Evidence from randomised control trials suggest probiotics are likely to improve GI inflammation and reduce the incidence of CF pulmonary exacerbations. However, the highly variable, low-quality data is a barrier to the implementation of probiotics into routine CF care. Epidemiological studies and clinical trials support the potential of dietary fibre and prebiotic supplements to beneficially modulate the microbiome in gastrointestinal conditions. To date, limited evidence is available on their safety and efficacy in CF. Variable responses to probiotics and prebiotics highlight the need for personalised approaches that consider an individual’s underlying microbiota, diet, and existing medications against the backdrop of the complex nutritional needs in CF.

Fecal Calprotectin and Phenotype Severity in Patients with Cystic Fibrosis: A Systematic Review and Meta-Analysis

Inflammation plays an important role in the outcome of patients with cystic fibrosis (CF). It may develop due to cystic fibrosis transmembrane conductance regulator protein dysfunction, pancreatic insufficiency, or prolonged pulmonary infection. Fecal calprotectin (FC) has been used as a noninvasive method to detect inflammation. Therefore, the aim of the current meta-analysis was to investigate the relationship between FC and phenotype severity in patients with CF. In this study, searches were conducted in PubMed, Science Direct, Scopus, and Embase databases up to August 2021 using terms such as "cystic fibrosis," "intestine," "calprotectin," and "inflammation." Only articles published in English and human studies were selected. The primary outcome was the level of FC in patients with CF. The secondary outcome was the relationship between FC and clinical severity. Statistical analysis was performed using Comprehensive Meta-Analysis software. Of the initial 303 references, only six articles met the inclusion criteria. The mean (95% confidence interval [CI]) level of FC was 256.5 mg/dL (114.1-398.9). FC levels were significantly associated with pancreatic insufficiency (mean, 243.02; 95% CI, 74.3 to 411.6; p=0.005; I²=0), pulmonary function (r=-0.39; 95% CI, -0.58 to -0.15; p=0.002; I²=60%), body mass index (r=-0.514; 95% CI, 0.26 to 0.69; p<0.001; I²=0%), and Pseudomonas colonization (mean, 174.77; 95% CI, 12.5 to 337.02; p=0.035; I²=71%). While FC is a reliable noninvasive marker for detecting gastrointestinal inflammation, it is also correlated with the severity of the disease in patients with CF.

Case report of compound CFTR variants in Korean siblings with cystic fibrosis: importance of differentiating cystic fibrosis from inflammatory bowel disease

The prevalence of cystic fibrosis (CF) is considerably lower in Asian populations compared with that of Caucasians. Cases of CF are typically due to mutations in the CF transmembrane conductance regulator gene with autosomal recessive inheritance. Here, we report two cases of newly diagnosed CF in Korea-a 13-year-old boy and his 5-year-old brother. The older brother was admitted to our hospital for evaluation and treatment of recurrent abdominal pain, frequent diarrhea, and failure to thrive. Fecal calprotectin (FC) was elevated, and when combining this with his clinical presentation, inflammatory bowel disease (IBD) or eosinophilic gastroenteritis (EoGE) was the first impression of his disease. Several ulcerative lesions were observed on ileocolonoscopy. However, incidental findings of suspicious bronchiectatic lesions were observed on plain radiography, which were confirmed by chest computed tomography. Moreover, diffuse bowel wall thickening with pancreatic atrophy was also incidentally detected by computed tomography of the abdomen. Comprehensively, these findings were highly suggestive of CF. Therefore, diagnostic exome sequencing was conducted, which revealed compound heterozygous variants of c.263T>G (p.Leu88*) and c.2977G>T (p.Asp993Tyr) in the CF transmembrane conductance regulator gene. Although symptoms in the younger brother were not as prominent as the older brother, genetic test was also conducted, which revealed the same mutation. We report the identification of a novel variant, p.Asp993Tyr, in siblings with Korean heritage. Although CF is rare in Koreans, it should be included in the differential diagnosis of IBD.

Screening strategy for gastrointestinal and hepatopancreatobiliary cancers in cystic fibrosis

Based on systematic review and meta-analysis, the risk for developing cancers in patients with cystic fibrosis (CF) is known to be significantly greater than in the general population, including site-specific cancers of the esophagus, small bowel, colon, liver, biliary tract, and pancreas. An even higher risk has been found in patients who have severe CF transmembrane conductance regulator (CFTR) genotypes or who have undergone organ transplantation and are immunosuppressed. The risk continues to rise as life expectancies steadily climb due to advancements in medical care and treatment for CF. The colorectal cancer risk is at such a high level that CF has now been declared a hereditary colon cancer syndrome by the Cystic Fibrosis Foundation. The CFTR gene has been strongly-associated with the development of gastrointestinal (GI) cancers and mortality in the CF population. Even CF carriers have shown an increased rate of GI cancers compared to the general population. Several limitations exist with the reported guidelines for screening of GI and hepatopancreatobiliary cancers in the CF population, which are largely universal and are still emerging. There is a need for more precise screening based on specific risk factors, including CFTR mutation, medical co-morbidities (such as gastroesophageal reflux disease, distal intestinal obstruction syndrome, and diabetes mellitus), familial risks for each cancer, gender, age, and other factors. In this review, we propose changes to the guidelines for GI screening of patients with CF. With the development of CFTR modulators, additional studies are necessary to elucidate if there is an effect on cancer risk.

ABCC7/CFTR Expression Is Associated with the Clinical Course of Ulcerative Colitis Patients

Inflammatory bowel disease includes ulcerative colitis (UC) and Crohn's disease (CD) of unknown etiology. The expression of ATP-binding cassette (ABC) family proteins has been associated with drug resistance and development of UC. The cystic fibrosis transmembrane conductance regulator (CFTR) or also known as ABCC7 is involved in the inflammatory chronic response. The aim of this study was to evaluate the role of ABCC7/CFTR in UC patients and normal controls without inflammation. This is an exploratory, observational, and cross-sectional study that included a total of 62 patients with UC and normal controls. Gene expression of CFTR was measured by RT-PCR, and protein expression of CFTR was determined by western blot analysis. We found a significant downregulation of the CFTR gene expression in patients with active UC compared to normal controls without inflammation (P < 0.004); even the gene expression of CFTR was decreased in remission UC patients compared to normal controls without inflammation (P = 0.04). The CFTR gene expression was associated with the clinical course of UC and the protein expression of CFTR was decreased in active UC patients compared to normal controls without inflammation suggesting that this molecule might play a role in the inflammation in UC patients.

Intestinal organoid-based 2D monolayers mimic physiological and pathophysiological properties of the pig intestine

Gastrointestinal infectious diseases remain an important issue for human and animal health. Investigations on gastrointestinal infectious diseases are classically performed in laboratory animals leading to the problem that species-specific models are scarcely available, especially when it comes to farm animals. The 3R principles of Russel and Burch were achieved using intestinal organoids of porcine jejunum. These organoids seem to be a promising tool to generate species-specific in vitro models of intestinal epithelium. 3D Organoids were grown in an extracellular matrix and characterized by qPCR. Organoids were also seeded on permeable filter supports in order to generate 2D epithelial monolayers. The organoid-based 2D monolayers were characterized morphologically and were investigated regarding their potential to study physiological transport properties and pathophysiological processes. They showed a monolayer structure containing different cell types. Moreover, their functional activity was demonstrated by their increasing transepithelial electrical resistance over 18 days and by an active glucose transport and chloride secretion. Furthermore, the organoid-based 2D monolayers were also confronted with cholera toxin derived from Vibrio cholerae as a proof of concept. Incubation with cholera toxin led to an increase of short-circuit current indicating an enhanced epithelial chloride secretion, which is a typical characteristic of cholera infections. Taken this together, our model allows the investigation of physiological and pathophysiological mechanisms focusing on the small intestine of pigs. This is in line with the 3R principle and allows the reduction of classical animal experiments.

Surveillance of Colorectal Cancer (CRC) in Cystic Fibrosis (CF) Patients

Cystic Fibrosis (CF) is the commonest inherited genetic disorder in Caucasians due to a mutation in the gene CFTR (Cystic Fibrosis Transmembrane Conductance Regulator), and it should be considered as an Inherited Colorectal Cancer (CRC) Syndrome. In the United States, physicians of CF Foundation established the “Developing Innovative Gastroenterology Speciality Training Program” to increase the research on CF in gastrointestinal and hepatobiliary diseases. The risk to develop a CRC is 5–10 times higher in CF patients than in the general population and even greater in CF patients receiving immunosuppressive therapy due to organ transplantation (30-fold increased risk relative to the general population). Colonoscopy should be considered the best screening for CRC in CF patients. The screening colonoscopy should be started at the age of 40 in CF patients and, if negative, a new colonoscopy should be performed every 5 years and every 3 years if adenomas are detected. For transplanted CF patients, the screening colonoscopy could be started at the age of 35, in transplanted patients at the age of 30 and, if before, at the age of 30. CF transplanted patients, between the age of 35 and 55, must repeat colonoscopy every 3 years. Our review draws attention towards the clinically relevant development of CRC in CF patients, and it may pave the way for further screenings and studies.

The Use of Fecal Calprotectin Testing in Paediatric Disorders: A Position Paper of the European Society for Paediatric Gastroenterology and Nutrition Gastroenterology Committee

OBJECTIVES

The aim of the study was to review the evidence regarding the clinical use and value of fecal calprotectin (FC) measurements in different gastrointestinal disorders in children.

METHODS

A literature search was conducted in the PubMed, MEDLINE, EMBASE, and Cochrane databases until October 31, 2019. Subtopics were identified and each assigned to individual authors.

RESULTS

A total of 28 recommendations were voted on using the nominal voting technique. Recommendations are given related to sampling, measurement methods, and results interpretation. The 14 authors anonymously voted on each recommendation using a 9-point scale (1 strongly disagree to 9 fully agree). Consensus was considered achieved if at least 75% of the authors voted 6, 7, 8, or 9.

CONCLUSIONS

Consensus was reached for all recommendations. Limitations for the use of FC in clinical practice include variability in extraction methodology, performance of test kits as well as the need to establish local reference ranges because of the influence of individual factors, such as age, diet, microbiota, and drugs. The main utility of FC measurement at present is in the diagnosis and monitoring of inflammatory bowel disease (IBD) as well as to differentiate it from functional gastrointestinal disorders (FAPDs). FC, however, has neither utility in the diagnosis of infantile colic nor to differentiate between functional and organic constipation. A rise in FC concentration, may alert to the risk of developing necrotizing enterocolitis and help identifying gastrointestinal involvement in children with Henoch-Schönlein purpura. FC measurement is of little value in Cow's Milk Protein Allergy, coeliac disease (CD), and cystic fibrosis. FC does neither help to distinguish bacterial from viral acute gastroenteritis (AGE), nor to diagnose Helicobacter Pylori infection, small intestinal bacterial overgrowth (SIBO), acute appendicitis (AA), or intestinal polyps.

Animal Models and Their Role in Understanding the Pathophysiology of Cystic Fibrosis-Associated Gastrointestinal Lesions

The life expectancy of cystic fibrosis (CF) patients has greatly increased over the past decade, and researchers and clinicians must now navigate complex disease manifestations that were not a concern prior to the development of modern therapies. Explosive growth in the number of CF animal models has also occurred over this time span, clarifying CF disease pathophysiology and creating opportunities to understand more complex disease processes associated with an aging CF population. This review focuses on the CF-associated pathologies of the gastrointestinal system and how animal models have increased our understanding of this complex multisystemic disease. Although CF is primarily recognized as a pulmonary disease, gastrointestinal pathology occurs very commonly and can affect the quality of life for these patients. Furthermore, we discuss how next-generation genetic engineering of larger animal models will impact the field's understanding of CF disease pathophysiology and the development of novel therapeutic strategies.

Etiology and Management of Pediatric Intestinal Failure: Focus on the Non-Digestive Causes

Background: Intestinal failure (IF) is defined as reduction in functioning gut mass below the minimal amount necessary for adequate digestion and absorption. In most cases, IF results from intrinsic diseases of the gastrointestinal tract (digestive IF) (DIF); few cases arise from digestive vascular components, gut annexed (liver and pancreas) and extra-digestive organs or from systemic diseases (non-digestive IF) (NDIF). The present review revised etiology and treatments of DIF and NDIF, with special focus on the pathophysiological mechanisms, whereby NDIF develops. Methods: We performed a comprehensive search of published literature from January 2010 to the present by selecting the following search strings: “intestinal failure” OR “home parenteral nutrition” OR “short bowel syndrome” OR “chronic pseudo-obstruction” OR “chronic intestinal pseudo-obstruction” OR “autoimmune enteropathy” OR “long-term parenteral nutrition”. Results: We collected overall 1656 patients with well-documented etiology of IF: 1419 with DIF (86%) and 237 with NDIF (14%), 55% males and 45% females. Among DIF cases, 66% had SBS and among NDIF cases 90% had malabsorption/maldigestion. Conclusions: The improved availability of diagnostic and therapeutic tools has increased prevalence and life expectancy of rare and severe diseases responsible for IF. The present review greatly expands the spectrum of knowledge on the pathophysiological mechanisms through which the diseases not strictly affecting the intestine can cause IF. In view of the rarity of the majority of pediatric IF diseases, the development of IF Registries is strongly required; in fact, through information flow within the network, the Registries could improve IF knowledge and management.

Impact of Altered Gut Microbiota and Its Metabolites in Cystic Fibrosis

Cystic fibrosis (CF) is the most common lethal, multisystemic genetic disorder in Caucasians. Mutations in the gene encoding the cystic fibrosis transmembrane regulator (CFTR) protein are responsible for impairment of epithelial anionic transport, leading to impaired fluid regulation and pH imbalance across multiple organs. Gastrointestinal (GI) manifestations in CF may begin in utero and continue throughout the life, resulting in a chronic state of an altered intestinal milieu. Inherent dysfunction of CFTR leads to dysbiosis of the gut. This state of dysbiosis is further perpetuated by acquired factors such as use of antibiotics for recurrent pulmonary exacerbations. Since the gastrointestinal microbiome and their metabolites play a vital role in nutrition, metabolic, inflammatory, and immune functions, the gut dysbiosis will in turn impact various manifestations of CF-both GI and extra-GI. This review focuses on the consequences of gut dysbiosis and its metabolic implications on CF disease and possible ways to restore homeostasis.

The Extrapulmonary Effects of Cystic Fibrosis Transmembrane Conductance Regulator Modulators in Cystic Fibrosis

The effects of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators on lung function, pulmonary exacerbations, and quality of life have been well documented. However, CF is a multiorgan disease, and therefore an evidence base is emerging on the systemic effects of CFTR modulators beyond the pulmonary system. This is of great clinical importance, as many of these studies provide proof of concept that CFTR modulators might be used one day to prevent or treat extrapulmonary manifestations stemming from CFTR dysfunction. In this concise review of the literature, we summarize the results of key publications that have evaluated the effects of CFTR modulators on weight and growth, pancreatic function, the gastrointestinal and hepatobiliary systems, sinus disease, bone disease, exercise tolerance, fertility, mental health, and immunity. Although many of these studies have reported beneficial extrapulmonary effects related to the use of ivacaftor (IVA) in patients with CF with at least one gating mutation, most of the evidence is low or very low quality, given the limited number of patients evaluated and the lack of control groups. Based on an even smaller number of studies evaluating the extrapulmonary effects of lumacaftor-IVA, the benefits are less clear. Although limited, these studies may provide the basis for future clinical trials to evaluate CFTR modulators on the extrapulmonary manifestations of CF.

Molecular mechanism mediating enteric bacterial translocation after severe burn: the role of cystic fibrosis transmembrane conductance regulator

Background

Gut ischemia and hypoxia post severe burn leads to breakdown of intestinal epithelial barrier and enteric bacterial translocation (EBT), resulting in serious complications, such as systemic inflammatory response syndrome, sepsis and multiple organ failure. Cystic fibrosis transmembrane conductance regulator (CFTR) is known to be downregulated by hypoxia and modulate junctional complexes, which are crucial structures maintaining the intestinal barrier. This study aimed to investigate whether CFTR plays a role in both regulating the intestinal barrier and mediating EBT post severe burn, as well as the signaling pathways involved in these processes.

Methods

An in vitro Caco-2 cell model subjected to hypoxic injury and an in vivo mouse model with a 30% total body surface area full-thickness dermal burn were established. DF 508 mice (mice with F508del CFTR gene mutation) were used as an in vivo model to further demonstrate the role of CFTR in maintaining normal intestinal barrier function. QRT-PCR, western blot, ELISA, TER assay and immunofluorescence staining were used to detect the expression and localization of CFTR and tight junction proteins, as well as the function of tight junctions.

Results

Our data indicated that, in Caco-2 cells, the hypoxia condition significantly reduced CFTR expression; activated extracellular signal-regulated kinase and nuclear factor-κB signaling; elevated secretion of inflammatory factors (tumor necrosis factor-α, interleukin-1β and interleukin-8); downregulated zonula occludens-1, occludin and E-cadherin expression; decreased transepithelial electrical resistance values; and led to a cellular mislocation of ZO-1. More importantly, knockdown of CFTR caused similar alterations. The upregulation of inflammatory factors and downregulation of tight junction proteins (ZO-1 and occludin) induced by knockdown of CFTR could be reversed by specific extracellular signal-regulated kinase or nuclear factor-κB inhibition. In support of the in vitro data, exuberant secretion of pro-inflammatory mediators and EBT was observed in the intestine of severely burnt mice in vivo. EBT occurred in DF508 mice (mice with the F508del CFTR gene mutation), accompanied by augmented tumor necrosis factor-α, interleukin-1β and interleukin-8 levels in the ileum compared to wildtype mice. In addition, vitamin D3 was shown to protect the intestinal epithelial barrier from hypoxic injury.

Conclusions

Collectively, the present study illustrated that CFTR and downstream signaling were critical in modulating the intestinal epithelial junction and EBT post severe burn.

Increased Fecal Calprotectin Is Associated with Worse Gastrointestinal Symptoms and Quality of Life Scores in Children with Cystic Fibrosis

In cystic fibrosis (CF), cystic fibrosis transmembrane regulator (CFTR) dysfunction leads to digestive disorders that promote intestinal inflammation and dysbiosis enhancing gastrointestinal symptoms. In pancreatic insufficiency CF patients, both intestinal inflammation and dysbiosis, are associated with an increase in the fecal calprotectin (FC) level. However, associations between the FC level, gastrointestinal symptoms, and quality of life (QoL) remain poorly studied. We aimed to assess such associations in pancreatic insufficiency CF children. The FC level was measured in pancreatic insufficiency CF children’s stool samples. Children and their parents completed two questionnaires: The Gastrointestinal Symptoms Scales 3.0-PedsQL^TM and the Quality of Life Pediatric Inventory 4.0-PedsQL^TM. Lower scores indicated worse symptomatology or QoL. Thirty-seven CF children were included. A FC level above 250 µg/g was associated with worse gastrointestinal symptoms and QoL scores. The FC level was inversely correlated with several gastrointestinal scores assessed by children (i.e., Total, “Heart Burn Reflux”, “Nausea and Vomiting”, and “Gas and Bloating”). Several QoL scores were correlated with gastrointestinal scores. The FC level was weakly associated with clinical parameters. Some gastrointestinal and QoL scores were related to disease severity associated parameters. In CF, the FC level, biomarker previously related to intestinal inflammation and dysbiosis, was associated with worse digestive symptoms and QoL scores.

Reduced Intestinal Inflammation With Lumacaftor/Ivacaftor in Adolescents With Cystic Fibrosis

A chronic intestinal inflammation may occur in patients with cystic fibrosis (CF), while no therapeutic management is proposed. Although Lumacaftor/Ivacaftor is well-known to modulate the defective cystic fibrosis transmembrane conductance regulator (CFTR) protein in lungs, no data are available on the impact of this treatment on CF intestinal disorders. We, therefore, investigated the evolution of intestinal inflammation after initiation of Lumacaftor/Ivacaftor in CF adolescents (median of follow-up: 336 days [IQR: 278;435]). Median fecal calprotectin concentrations decreased significantly after Lumacaftor/Ivacaftor initiation (102 μg/g [IQR: 69-210]) compared with the baseline (713 μg/g (IQR:148-852), P = 0.001). To our knowledge, this study showed for the first time that CF-related intestinal inflammation is improved by Lumacaftor/Ivacaftor treatment.

Oral Glutathione and Growth in Cystic Fibrosis: A Multicenter, Randomized, Placebo-controlled, Double-blind Trial

OBJECTIVES

The nutritional status of children with cystic fibrosis (CF) is associated with mortality and morbidity. Intestinal inflammation may contribute to impaired digestion, absorption, and nutrient utilization in patients with CF and oral glutathione may reduce inflammation, promoting improved nutritional status in patients with CF.

METHODS

The GROW study was a prospective, multicenter, randomized, placebo-controlled, double-blind, phase II clinical trial in pancreatic insufficient patients with CF between the ages of 2 and 10 years. Patients received reduced glutathione or placebo orally daily for 24 weeks. The primary endpoint was the difference in change in weight-for-age z-scores from baseline through week 24 between treatment groups. Secondary endpoints included other anthropometrics, serum, and fecal inflammatory markers in addition to other clinical outcomes.

RESULTS

Fifty-eight participants completed the study. No significant differences were seen between glutathione (n = 30) and placebo (n = 28) groups in the 6-month change in weight-for-age z-score (-0.08; 95% CI: -0.22 to 0.06; P = 0.25); absolute change in weight (kg) (-0.18; 95% CI: -0.55 to 0.20; P = 0.35); or absolute change in BMI kg/m (-0.06; 95% CI: -0.37 to 0.25; P = 0.69). There were no significant differences in other secondary endpoints. Overall, glutathione was safe and well tolerated.

CONCLUSIONS

Oral glutathione supplementation did not impact growth or change serum or fecal inflammatory markers in pancreatic insufficient children with CF when compared with placebo.

Long-term docosahexaenoic acid (DHA) supplementation in cystic fibrosis patients: a randomized, multi-center, double-blind, placebo-controlled trial

BACKGROUND

Cystic fibrosis (CF) patients have an alteration in fatty acid (FA) metabolism, associated with increased omega-6 and low omega-3 FA. Previous studies on supplementation with omega-3 FA in CF had contradictory results, and to date there is no evidence to recommend routine use of omega-3 supplements in CF patients. We hypothesized that long-term supplementation with docosahexaenoic acid (DHA) will have beneficial effects in these patients, by reducing pulmonary, systemic and intestinal inflammation.

METHODS

This was a randomized, double-blind, parallel, placebo-controlled trial. CF patients (age >2 months) were randomized to receive a seaweed DHA oil solution (50 mg/Kg/day) or matching placebo for 48 weeks. Primary outcomes were pulmonary (interleukin [IL]-8), systemic (IL-8) and intestinal (calprotectin) inflammatory biomarkers. Secondary outcomes included other pulmonary (IL-1β, IL-6, neutrophil elastase, lactate and calprotectin) and systemic (serum-IL-1β, IL-6) inflammatory biomarkers, as well as clinical outcomes (FEV₁, pulmonary exacerbations, antibiotic use, nutritional status and quality of life).

RESULTS

Ninety six CF patients, 44 female, age 14.6±11.9 years (48 DHA and 48 placebo) were included. At trial completion, there were no differences in all primary outcomes [serum-IL-8 (p=0.909), respiratory-IL-8 (p=0.384) or fecal calprotectin (p=0.948)], all secondary inflammatory biomarkers, or in any of the clinical outcomes evaluated. There were few adverse events, with similar incidence in both study groups.

CONCLUSION

In this study, long-term DHA supplementation in CF patients was safe, but did not offer any benefit on inflammatory biomarkers, or in clinical outcomes compared with placebo. (NCT01783613).

Cystic fibrosis and the gut

Cystic fibrosis (CF) is a recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The gene product, CFTR protein, has important manifestations in the intestine, pancreas and hepatobiliary system. Increased survival has caused CF to be primarily an adult disease today. Physicians must be knowledgeable as to the varied phenotype in the gastrointestinal tract. This review will outline the main gastrointestinal manifestations including a section on gastrointestinal malignancy in CF. Novel treatments treating the basic effect in CF are now being introduced and their effects on the gastrointestinal tract are discussed.

Fecal calprotectin in the pediatric population: a 2020 update

Calprotectin is a calcium and zinc-binding protein, formed by a hetero complex of S100A8 and S100A9 proteins, which belong to the S-100 protein family consisting in more than 20 different proteins with a tissue-specific expression pattern. This protein is secreted extracellularly from stimulated neutrophils or released by cell disruption or death. The presence of calprotectin in feces quantitatively relates to neutrophil migration toward the gastrointestinal (GI) tract; thus, it represents a useful marker of intestinal inflammation. Fecal calprotectin (FC) has been proven largely useful for determining the inflammatory origin of GI symptoms differentiating between organic and non-organic diseases. Indeed, increased FC levels are also seen in gastroenteritis, microscopic colitis, polyps, malignancies and cystic fibrosis. To date, there are many evidences regarding usefulness in the detection of fecal calprotectin for the management of gastrointestinal disorders, both in children and adults but, especially in the pediatric population, still clear indications for its use are lacking. Its incorporation in primary care reduces the risk of missing an organic disease and facilitates the indication for expensive and invasive investigations as colonoscopy. We herein review and discuss the last evidence on the usefulness of FC in children, with its current indications and future prospective.

Cystic Fibrosis, CFTR, and Colorectal Cancer

Cystic fibrosis (CF), caused by biallelic inactivating mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, has recently been categorized as a familial colorectal cancer (CRC) syndrome. CF patients are highly susceptible to early, aggressive colorectal tumor development. Endoscopic screening studies have revealed that by the age of forty 50% of CF patients will develop adenomas, with 25% developing aggressive advanced adenomas, some of which will have already advanced to adenocarcinomas. This enhanced risk has led to new CF colorectal cancer screening recommendations, lowering the initiation of endoscopic screening to age forty in CF patients, and to age thirty in organ transplant recipients. The enhanced risk for CRC also extends to the millions of people (more than 10 million in the US) who are heterozygous carriers of CFTR gene mutations. Further, lowered expression of CFTR is reported in sporadic CRC, where downregulation of CFTR is associated with poor survival. Mechanisms underlying the actions of CFTR as a tumor suppressor are not clearly understood. Dysregulation of Wnt/β-catenin signaling and disruption of intestinal stem cell homeostasis and intestinal barrier integrity, as well as intestinal dysbiosis, immune cell infiltration, stress responses, and intestinal inflammation have all been reported in human CF patients and in animal models. Notably, the development of new drug modalities to treat non-gastrointestinal pathologies in CF patients, especially pulmonary disease, offers hope that these drugs could be repurposed for gastrointestinal cancers.

A high prevalence of chronic gastrointestinal symptoms in adults with cystic fibrosis is detected using tools already validated in other GI disorders

Background

People with cystic fibrosis (CF) report a variety of gastrointestinal (GI) symptoms, independent of pancreatic enzyme insufficiency (PEI), reminiscent of other chronic GI disorders. There are currently no accepted or validated assessment tools and neither the range, frequency nor severity of GI symptoms has been systematically described in CF. We present results of a cross-sectional study using established tools and compare them to current measures of quality of life (QOL).

Methods

Consecutive patients attending specialist CF appointments were asked to complete questionnaires including the GI Symptom Rating Scale (GSRS); Irritable Bowel Syndrome Symptom Severity Score (IBS-SSS) and Cystic Fibrosis Questionnaire (CFQ-R). Questionnaire terminology was altered to replace references to 'IBS' with 'GI symptoms'.

Results

In total, 107 patients were recruited (mean age, 27.8 ± 9.6 years; 60 female), and 94 (88%) had PEI. Body mass index was 22.1 ± 3.6 kg/m², forced expiratory volume in one second was 59 + 27.7% predicted. Fifty-three (49.5%) were p.Phe508del homozygous. Overall 69/107 (65%) reported significant GI symptoms independent of PEI or adherence to pancreatic enzyme replacement therapy (PERT), with the four most frequent being attributable to the lower GI tract: bloating/distension, flatulence, abdominal pain and borborygmi (gurgling). There was no numerical correlation between any CFQ-R domain (particularly Digestion domain) and GSRS or SSS.

Conclusion

This is the first systematic study measuring GI symptoms in CF using validated GI tools. Symptoms are not related to PERT or genotype and appear to be captured well by the GSRS. Further research will study longitudinal changes with treatment, and therapeutic trials in CF may use these tools to demonstrate a positive impact on 'non-respiratory' symptoms and QOL.