Age-related levels of fecal M2-pyruvate kinase in children with cystic fibrosis and healthy children 0 to 10years old

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.

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.

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.

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.

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.

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 intestinal virome in children with cystic fibrosis differs from healthy controls

Intestinal bacterial dysbiosis is evident in children with cystic fibrosis (CF) and intestinal viruses may be contributory, given their influence on bacterial species diversity and biochemical cycles. We performed a prospective, case-control study on children with CF and age and gender matched healthy controls (HC), to investigate the composition and function of intestinal viral communities. Stool samples were enriched for viral DNA and RNA by viral extraction, random amplification and purification before sequencing (Illumina MiSeq). Taxonomic assignment of viruses was performed using Vipie. Functional annotation was performed using Virsorter. Inflammation was measured by calprotectin and M2-pyruvate kinase (M2-PK). Eight CF and eight HC subjects were included (50% male, mean age 6.9 ± 3.0 and 6.4 ± 5.3 years, respectively, p = 0.8). All CF subjects were pancreatic insufficient. Regarding the intestinal virome, no difference in Shannon index between CF and HC was identified. Taxonomy-based beta-diversity (presence-absence Bray-Curtis dissimilarity) was significantly different between CF and HC (R² = 0.12, p = 0.001). Myoviridae, Faecalibacterium phage FP Taranis and unclassified Gokushovirinae were significantly decreased in CF compared with HC (q<0.05). In children with CF (compared to HC), the relative abundance of genes annotated to (i) a peptidoglycan-binding domain of the peptidoglycan hydrolases (COG3409) was significantly increased (q<0.05) and (ii) capsid protein (F protein) (PF02305.16) was significantly decreased (q<0.05). Picornavirales, Picornaviridae, and Enterovirus were found to positively correlate with weight and BMI (r = 0.84, q = 0.01). Single-stranded DNA viruses negatively correlated with M2-PK (r = -0.86, q = 0.048). Children with CF have an altered intestinal virome compared to well-matched HC, with both taxonomic and predicted functional changes. Further exploration of Faecalibacterium phages, Gokushovirinae and phage lysins are warranted. Intestinal viruses and their functions may have important clinical implications for intestinal inflammation and growth in children with CF, potentially providing novel therapeutic targets.

Probiotics for people with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multisystem disease and the importance of growth and nutrition has been well established, given its implications for lung function and overall survival. It has been established that intestinal dysbiosis (i.e. microbial imbalance) and inflammation is present in people with CF. Probiotics are commercially available (over-the-counter) and may improve both intestinal and overall health.

OBJECTIVES

To assess the efficacy and safety of probiotics for improving health outcomes in children and adults with CF.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last register search: 20 January 2020. We also searched ongoing trials registries and the reference lists of relevant articles and reviews. Date of last search: 29 January 2019.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials (RCTs) assessing efficacies and safety of probiotics in children and adults with CF. Cross-over RCTs with a washout phase were included and for those without a washout period, only the first phase of each trial was analysed.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed the risk of bias of the included trials; we used GRADE to assess the certainty of the evidence. We contacted trial authors for additional data. Meta-analyses were undertaken on outcomes at several time points.

MAIN RESULTS

We identified 17 trials and included 12 RCTs (11 completed and one trial protocol - this trial was terminated early) (464 participants). Eight trials included only children, whilst four trials included both children and adults. Trial duration ranged from one to 12 months. Nine trials compared a probiotic (seven single strain and three multistrain preparations) with a placebo preparation, two trials compared a synbiotic (multistrain) with a placebo preparation and one trial compared two probiotic preparations. Overall we judged the risk of bias in the 12 trials to be low. Three trials had a high risk of performance bias, two trials a high risk of attrition bias and six trials a high risk of reporting bias. Only two trials were judged to have low or unclear risk of bias for all domains. Four trials were sponsored by grants only, two trials by industry only, two trials by both grants and industry and three trials had an unknown funding source. Combined data from four trials (225 participants) suggested probiotics may reduce the number of pulmonary exacerbations during a four to 12 month time-frame, mean difference (MD) -0.32 episodes per participant (95% confidence interval (CI) -0.68 to 0.03; P = 0.07) (low-certainty evidence); however, the 95% CI includes the possibility of both an increased and a reduced number of exacerbations. Additionally, two trials (127 participants) found no evidence of an effect on the duration of antibiotic therapy during the same time period. Combined data from four trials (177 participants) demonstrated probiotics may reduce faecal calprotectin, MD -47.4 µg/g (95% CI -93.28 to -1.54; P = 0.04) (low-certainty evidence), but the results for other biomarkers mainly did not show any difference between probiotics and placebo. Two trials (91 participants) found no evidence of effect on height, weight or body mass index (low-certainty evidence). Combined data from five trials (284 participants) suggested there was no difference in lung function (forced expiratory volume at one second (FEV₁) % predicted) during a three- to 12-month time frame, MD 1.36% (95% CI -1.20 to 3.91; P = 0.30) (low-certainty evidence). Combined data from two trials (115 participants) suggested there was no difference in hospitalisation rates during a three- to 12-month time frame, MD -0.44 admissions per participant (95% CI -1.41 to 0.54; P = 0.38) (low-certainty evidence). One trial (37 participants) reported health-related quality of life and while the parent report favoured probiotics, SMD 0.87 (95% CI 0.19 to 1.55) the child self-report did not identify any effect, SMD 0.59 (95% CI -0.07 to 1.26) (low-certainty evidence). There were limited results for gastrointestinal symptoms and intestinal microbial profile which were not analysable. Only four trials and one trial protocol (298 participants) reported adverse events as a priori hypotheses. No trials reported any deaths. One terminated trial (12 participants and available as a protocol only) reported a severe allergic reaction (severe urticaria) for one participant in the probiotic group. Two trials reported a single adverse event each (vomiting in one child and diarrhoea in one child). The estimated number needed to harm for any adverse reaction (serious or not) is 52 people (low-certainty evidence).

AUTHORS' CONCLUSIONS

Probiotics significantly reduce faecal calprotectin (a marker of intestinal inflammation) in children and adults with CF, however the clinical implications of this require further investigation. Probiotics may make little or no difference to pulmonary exacerbation rates, however, further evidence is required before firm conclusions can be made. Probiotics are associated with a small number of adverse events including vomiting, diarrhoea and allergic reactions. In children and adults with CF, probiotics may be considered by patients and their healthcare providers. Given the variability of probiotic composition and dosage, further adequately-powered multicentre RCTs of at least 12 months duration are required to best assess the efficacy and safety of probiotics for children and adults with CF.

Gut Microbiota in Children With Cystic Fibrosis: A Taxonomic and Functional Dysbiosis

Intestinal dysbiosis has been observed in children with cystic fibrosis (CF), yet the functional consequences are poorly understood. We investigated the functional capacity of intestinal microbiota and inflammation in children with CF. Stool samples were collected from 27 children with CF and 27 age and gender matched healthy controls (HC) (aged 0.8-18 years). Microbial communities were investigated by iTag sequencing of 16S rRNA genes and functional profiles predicted using Tax4Fun. Inflammation was measured by faecal calprotectin and M2-pyruvate kinase. Paediatric CF gastrointestinal microbiota demonstrated lower richness and diversity compared to HC. CF samples exhibited a marked taxonomic and inferred functional dysbiosis when compared to HC. In children with CF, we predicted an enrichment of genes involved in short-chain fatty acid (SCFA), antioxidant and nutrient metabolism (relevant for growth and nutrition) in CF. The notion of pro-inflammatory GI microbiota in children with CF is supported by positive correlations between intestinal inflammatory markers and both genera and functional pathways. We also observed an association between intestinal genera and both growth z-scores and FEV1%. These taxonomic and functional changes provide insights into gastrointestinal disease in children with CF and future gastrointestinal therapeutics for CF should explore the aforementioned pathways and microbial changes.

Intestinal Inflammation in Children with Cystic Fibrosis Is Associated with Crohn's-Like Microbiota Disturbances

Cystic fibrosis (CF) is a systemic genetic disease that leads to pulmonary and digestive disorders. In the majority of CF patients, the intestine is the site of chronic inflammation and microbiota disturbances. The link between gut inflammation and microbiota dysbiosis is still poorly understood. The main objective of this study was to assess gut microbiota composition in CF children depending on their intestinal inflammation. We collected fecal samples from 20 children with CF. Fecal calprotectin levels were measured and fecal microbiota was analyzed by 16S rRNA sequencing. We observed intestinal inflammation was associated with microbiota disturbances characterized mainly by increased abundances of Staphylococcus, Streptococcus, and Veillonella dispar, along with decreased abundances of Bacteroides, Bifidobacterium adolescentis, and Faecalibacterium prausnitzii. Those changes exhibited similarities with that of Crohn's disease (CD), as evidenced by the elevated CD Microbial-Dysbiosis index that we applied for the first time in CF. Furthermore, the significant over-representation of Streptococcus in children with intestinal inflammation appears to be specific to CF and raises the issue of gut-lung axis involvement. Taken together, our results provide new arguments to link gut microbiota and intestinal inflammation in CF and suggest the key role of the gut-lung axis in the CF evolution.

Impact of CFTR modulation with Ivacaftor on Gut Microbiota and Intestinal Inflammation

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Next to progressive airway disease, CF is also associated with intestinal inflammation and dysbiosis. Ivacaftor, a CFTR potentiator, has improved pulmonary and nutritional status but its effects on the intestinal microbiota and inflammation are unclear. Hence, we assessed the changes on the intestinal microbial communities (16S rRNA variable 3 gene region) and inflammatory markers (calprotectin and M2-pyruvate kinase [M2-PK]) in 16 CF individuals (8 children and 8 adults) before and after (median 6.1 months) ivacaftor. Stool calprotectin significantly decreased following ivacaftor (median [IQR]: 154.4 [102.1–284.2] vs. 87.5 [19.5–190.2] mg/kg, P = 0.03). There was a significant increase in Akkermansia with ivacaftor. Increased abundance of Akkermansia was associated with normal stool M2-PK concentrations, and decreased abundances of Enterobacteriaceae correlated with decreased stool calprotectin concentrations. In summary, changes in the gut microbiome and decrease in intestinal inflammation was associated with Ivacaftor treatment among individuals with CF carrying at least one gating CFTR mutation. Thus, CFTR-modifying therapy may adequately improve the aberrant pathophysiology and milieu of the CF gut to favor a more healthy microbiota, which in turn reduces intestinal inflammation.

Risk of gastrointestinal cancers in patients with cystic fibrosis: a systematic review and meta-analysis

BACKGROUND

The management and life expectancy of patients with cystic fibrosis have improved substantially in the past three decades, which has resulted in an increased number of these patients being diagnosed with malignancies. Our aim was to assess the risk of gastrointestinal cancers in patients with cystic fibrosis.

METHODS

In this systematic review and meta-analysis, we searched PubMed, MEDLINE, Google Scholar, Scopus, Embase, and Cochrane databases with no language restrictions for studies published from inception of the databases to Aug 1, 2017, assessing the risk of gastrointestinal cancers in patients with cystic fibrosis. We also searched abstracts from scientific meetings and the bibliographies of identified articles for additional references. Studies were included if they reported the standardised incidence ratio (SIR) or incidence ratio per person-years. No exclusion criteria with regard to patient characteristics (age, sex, comorbidities, cystic fibrosis mutation type), study setting (location and time period), or method of reporting cancer diagnoses were applied. The primary outcome was risk of gastrointestinal cancer and site-specific gastrointestinal cancers in patients with cystic fibrosis compared with the general population. Pooled summary estimates were calculated using a random-effects model, and subgroup analyses were done to establish whether risk of gastrointestinal cancer varied according to patient lung transplant status. The study is registered with PROSPERO, number CRD42017075396.

FINDINGS

Our search identified 95 681 records, of which six cohort studies including 99 925 patients (544 695 person-years) were eligible for the meta-analysis. The overall risk of gastrointestinal cancer was significantly higher in patients with cystic fibrosis than in the general population (pooled SIR 8·13, 95% CI 6·48-10·21; p<0·0001; log SIR 2·10, 95% CI 1·87-2·32; p<0·0001, I²=93·93%). Subgroup analyses showed that the risk of gastrointestinal cancer among patients with cystic fibrosis who had a lung transplant was increased compared with that of patients who did not receive a transplant (pooled SIR 21·13, 95% CI 14·82-30·14; p<0·0001; log SIR 3·05, 95% CI 2·70-3·41; p<0·0001, I²=28·52% vs pooled SIR 4·18, 3·10-5·62; p<0·0001; log SIR 1·43, 1·13-1·73; p<0·0001, I²=22·66%). The risk for the following site-specific cancers was also significantly increased in patients with cystic fibrosis compared with the general population: small bowel cancer (pooled SIR 18·94, 95% CI 9·37-38·27; p<0·0001; log SIR 2·94, 95% CI 2·24-3·64; p<0·0001, I²=38·61%), colon cancer (10·91, 8·42-14·11; p<0·0001; log SIR 2·39, 2·13-2·65; p<0·0001, I²=88·09%), biliary tract cancer (17·87, 8·55-37·36; p<0·0001; log SIR 2·88, 2·15-3·62; p<0·0001, I²=10·16%), and pancreatic cancer (6·18, 1·31-29·27; p=0·022; log SIR 1·82, 0·27-3·38; p<0·0001, I²=62·57%).

INTERPRETATION

Our study suggests that patients with cystic fibrosis had a significantly increased risk of gastrointestinal cancer compared with the general population, including small bowel, colon, biliary tract, and pancreatic cancers. These findings highlight the need to develop individualised screening strategies for site-specific gastrointestinal cancers in patients with cystic fibrosis.

FUNDING

None.