Characteristics of gastroesophageal reflux and potential risk of gastric content aspiration in children with cystic fibrosis

Infant Lung Function in Cystic Fibrosis: A Real-World Study

BACKGROUND

Previous research showed that lung function abnormalities are common in infants with cystic fibrosis (IwCF) but real-world data are missing.

METHODS

This single-center retrospective study analyzed infant lung function results from IwCF born in 2012-2018. The tests were conducted at Great Ormond Street Hospital, London, as part of routine care at 3 months, 1 year, and 2 years of age. Z-scores for SF6 Lung Clearance Index (zLCI), plethysmographic FRC (zFRCpleth) and FEV0.5 were derived. Microbiology and antibiotics prescription from 3 months before lung function assessments, up to the closest medical review following the lung function encounter, were analyzed, along with changes in management advised by the physician.

RESULTS

A total of 126 lung function encounters (n = 43 at 3 months, 46 at 1 year, 37 at 2 years) from 60 IwCF were included. LCI was abnormal (zLCI > 1.96) in 31% (12/39) of 3-month-olds (mean± zLCI 1.21 ± 1.08), 28% (12/43) of 1-year-olds and 19% (7/36) of 2-year-olds (mean± zLCI 1.13 ± 1.10). Among 74 cases with recent positive microbiology or abnormal chest findings at medical review, 100% (31/31) of those with abnormal lung function and 86% (37/43) of those with normal lung function (p = 0.04) had a recent antibiotic prescription or a change in clinical management. Conversely, in encounters with abnormal lung function but normal clinical findings, management changes occurred in only 12% (2/16) of cases.

CONCLUSION

In this real-word cohort of IwCF, clinical management was mainly influenced by clinical findings and only marginally by abnormal lung function (elevated FRC or LCI).

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

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

The foregut in cystic fibrosis

The aerodigestive organs share a kindred embryologic origin that allows for a more complete explanation as to how the foregut can remain a barrier to normalcy in people with cystic fibrosis (pwCF). The structures of the aerodigestive tract include the nasopharynx, the oropharynx, the hypopharynx, the esophagus, the stomach, as well as the supraglottic, glottic, and subglottic tubular airways (including the trachea). Additional gastrointestinal (GI) luminal/alimentary organs of the foregut include the duodenum. Extraluminal foregut structures include the liver, the gall bladder, the biliary tree, and the pancreas. There are a variety of neurologic controls within these complicated anatomic compartments to separate the transit of food and liquid from air. These structures share the same origin from the primitive foregut/mesenchyme. The vagus nerve is a critical structure that unites respiratory and digestive functions. This article comments on the interconnected nature of cystic fibrosis and the GI tract. As it relates to the foregut, this has been typically treated as simple "reflux" as the cause of worsened lung function in pwCF. That terms like gastroesophageal reflux (GER), gastroesophageal reflux disease (GERD), heartburn, and regurgitation are used interchangeably to reflect pathology further complicates matters; we offer a more physiologically accurate term called "GI-related aspiration" or "GRASP." Broadly, this term reflects that aspiration of foregut contents from the duodenum through the stomach to the esophagus, into the pharynx and the respiratory tree in pwCF. As a barrier to normalcy in pwCF, GRASP is fundamentally two disease processes-GERD and gastroparesis-that likely contribute most to the deterioration of lung disease in pwCF. In the modulator era, successful GRASP management will be critical, particularly in those post-lung transplantation (LTx), only through successful management of both GERD and gastroparesis. Standardization of clinical management algorithms for GRASP in CF-related GRASP is a key clinical and research gap preventing normalcy in pwCF; what exists nearly exclusively addresses surgical evaluations or offers guidance for the management of GI symptoms alone (with unclear parameters for respiratory disease considerations). We begin first by describing the result of GRASP damage to the lung in various stages of lung disease. This is followed by a discussion of the mechanisms by which the digestive tract can injure the lungs. We summarize what we anticipate future research directions will be to reduce the impact of GRASP as a barrier to normalcy in pwCF.

Bile effects on the Pseudomonas aeruginosa pathogenesis in cystic fibrosis patients with gastroesophageal reflux

Gastroesophageal reflux (GER) occurs in most cystic fibrosis (CF) patients and is the primary source of bile aspiration in the airway tract of CF individuals. Aspirated bile is associated with the severity of lung diseases and chronic inflammation caused by Pseudomonas aeruginosa as the most common pathogen of CF respiratory tract infections. P. aeruginosa is equipped with several mechanisms to facilitate the infection process, including but not limited to the expression of virulence factors, biofilm formation, and antimicrobial resistance, all of which are under the strong regulation of quorum sensing (QS) mechanism. By increasing the expression of lasI, rhlI, and pqsA-E, bile exposure directly impacts the QS network. An increase in psl expression and pyocyanin production can promote biofilm formation. Along with the loss of flagella and reduced swarming motility, GER-derived bile can repress the expression of genes involved in creating an acute infection, such as expression of Type Three Secretion (T3SS), hydrogen cyanide (hcnABC), amidase (amiR), and phenazine (phzA-E). Inversely, to cause persistent infection, bile exposure can increase the Type Six Secretion System (T6SS) and efflux pump expression, which can trigger resistance to antibiotics such as colistin, polymyxin B, and erythromycin. This review will discuss the influence of aspirated bile on the pathogenesis, resistance, and persistence of P. aeruginosa in CF patients.

Multicenter prospective study showing a high gastrointestinal symptom burden in cystic fibrosis

BACKGROUND AND AIMS

People with cystic fibrosis (PwCF) suffer from gastrointestinal (GI) symptoms affecting their quality of life (QOL). Despite the relevance of GI symptoms to the overall health of PwCF, a paucity of studies only have comprehensively assessed the prevalence, severity and QOL of GI symptoms in both children and adults with Cystic Fibrosis (CF).

METHODS

Eligible participants ≥2 years of age across 26 US CF centers were followed for 4 weeks. Three validated GI electronic patient-reported outcome measures (ePROMs) with a recall period of 2 weeks and a stool-specific questionnaire were administered weekly over four weeks. Total and domain scores of ePROMs were evaluated overall and in subgroups using linear mixed-effect models.

RESULTS

Of 402 enrolled, 58% were ≥ 18 years of age (52% male). The mean (SD) of the total score for PAC-SYM was 0.52 (0.55), for PAGI-SYM was 0.63 (0.67), and for PAC-QOL was 0.67 (0.55). For specific ePROM questions, prevalence of moderate to very severe symptoms were as follows: straining (20.3%), fullness (18.3%), incomplete bowel movements (17.1%), bloating (16.4%), distension (16.4%), abdominal pain (upper-5.1%, lower-7.5%). Comparing participants ≥18 versus <18, a higher prevalence of bloating (63.7% versus 27.3%), lower abdominal pain (39.8% vs 26.2%), stomach fullness (75.6% versus 56.2%), and abdominal distension (60.2% versus 34.9%) was found. Both age groups reported high treatment dissatisfaction as measured with PAC-QOL, mean 1.39 (95% CI: 1.30, 1.47).

CONCLUSION

GI symptoms were reported in all age ranges irrespective of gender, with higher prevalence observed amongst older and female subgroups. Dissatisfaction with GI targeted treatments were reported in a large proportion of participants despite therapy, highlighting an unmet need for clinical interventions.

CLINICALTRIALS

GOV: NCT03801993.

Characteristics of gastroesophageal reflux disease in children with interstitial lung disease

BACKGROUND

Childhood interstitial lung disease (chILD) is a rare group of respiratory tract disorders. One of the factors suggested to be associated with its etiopathogenesis is microaspiration related to gastroesophageal reflux disease (GERD). The aim of the present study was to determine the frequency and characteristics of GERD in children with chILD, with a particular focus on proximal GER episodes.

METHODS

This was a prospective cross-sectional study. Consecutive patients with chILD underwent 24-h multichannel intraluminal pH-impedance monitoring. Different types of gastroesophageal reflux episodes (GER) were recorded and compared with regard to the GERD diagnosis.

RESULTS

Sixty-two children (median age of 1.22 years) were included. GERD was diagnosed in 20 (32.3%) of them. The GERD (+) and GERD (-) subgroups differed mainly in their esophageal exposure to acid content (2.9 vs. 1.0%, p = 0.02) and bolus exposure (3.0 vs. 1.4%, p < 0.0001), as well as total number of GER (72.5 vs. 42.0 p = 0.0004), acid GER (35.5 vs. 15.0 p = 0.004), and acid proximal GER (21.0 vs. 12.0 p = 0.02). There were no differences in the number of proximal GER comparing GERD (+) and GERD (-) subgroups.

CONCLUSIONS

The frequency of GERD seems to be relatively high in the population of children with chILD used in this study. However, it has not demonstrated an association between proximal GER and GERD diagnosis in chILD, which casts uncertainty over the microaspiration theory proposed to link the two diseases. The latter conclusion, however, needs to be confirmed using more accurate aspiration assessment methods.

Combined multi-channel intraluminal impedance measurement and pHmetry in the detection of gastroesophageal reflux disease in children with cystic fibrosis

OBJECTIVE

To assess the prevalence of GERD exclusively by means of multichannel intraluminal impedanciometry associated with pH monitoring (MIIpH) and compare it with respiratory symptoms in children with CF. To compare MIIpH with pHmetry alone to perform GERD diagnosis.

METHODS

An analytical cross-sectional study was conducted with children diagnosed with CF who underwent MIIpH. Clinical and laboratory markers, including respiratory and digestive symptoms, were used for comparative analyses. High-resolution chest computed tomography was performed on patients with symptoms of chronic lung disease. Severity was classified according to the Bhalla score.

RESULTS

A total of 29 children < 10 yo (18 girls) were evaluated; 19 of whom with physiological GER and 10 with GERD. Of the children with GERD, seven had predominantly acid GER, two acid+non-acid GER, and one non-acid GER. Three patients had GERD diagnosed only by MIIpH. Bhalla scores ranged from seven to 17.75 with no significant relationship with GERD. The number of pulmonary exacerbations was associated with a decrease in esophageal clearance regardless of the position in pHmetry and MIIpH.

CONCLUSIONS

The prevalence of GERD was 34% in children with CF. There was no association between respiratory disease severity and GER types. MIIpH detected 30% more patients with GERD than pHmetry.

Brazilian Guidelines for Nutrition in Cystic Fibrosis

OBJECTIVE

To develop a scientific consensus on nutrition in cystic fibrosis.

METHODS

Sixteen coordinators elaborated relevant questions on nutritional therapy in cystic fibrosis, which were divided into six sections: nutritional assessment, nutritional recommendations, nutritional intervention, dietary counseling, special situations and enzyme replacement, and gastrointestinal manifestations. Two to three specialists in the field were responsible for each section and obtaining answers formulated based on standardized bibliographic searches. The available literature was searched in the PubMed®/MEDLINE database, after training and standardization of search strategies, to write the best level of evidence for the questions elaborated. Issues related to disagreement were discussed until a consensus was reached among specialists, based on the current scientific literature.

RESULTS

Forty-two questions were prepared and objectively answered, resulting in a consensus of nutritional therapy in cystic fibrosis.

CONCLUSION

This work enabled establishing a scientific consensus for nutritional treatment of cystic fibrosis patients.

Risk Factors for Bile Aspiration and its Impact on Clinical Outcomes

INTRODUCTION

Bile reflux may cause for lung allograft rejection, yet there are no studies that determine (i) the relationship between gastric and lung bile concentrations, (ii) whether bile is present in lungs of nontransplant patients, (iii) the relationship between gastric dysmotility and lung bile, (iv) the impact of reflux therapies on lung bile, and (v) whether lung bile worsens outcomes in nontransplant patients. This study will address these gaps in the literature.

METHODS

We prospectively recruited lung transplant (LTX) patients and nontransplant patients with respiratory symptoms (RP) and collected paired gastric and lung samples. Bile concentration and composition of samples was assessed using liquid chromatography-mass spectrometry. Bile results were compared with clinical parameters, including the presence of esophagitis, gastric dysmotility, and/or pathologic gastroesophageal reflux.

RESULTS

Seventy patients (48 RP and 22 LTX) were recruited. Overall, 100% of gastric and 98% of bronchoalveolar lavage samples contained bile. The mean gastric bile concentrations in RP and LTX patients were 280 ± 703 nmol/L and 1,004 ± 1721 nmol/L, respectively (P = 0.02). There was no difference in lung bile concentrations between RP (9 ± 30 nmol/L) and LTX (11 ± 15 nmol/L, P = 0.7). Patients with delayed gastric emptying had higher lung bile concentrations (15.5 ± 18.8 nmol/L) than patients with normal gastric emptying (4.8 ± 5.7 nmol/L, P = 0.05) independently of reflux burden. Proton pump inhibitor use increased the proportion of unconjugated gastric bile acids. High lung bile concentrations were associated with an increased risk of hospitalization and longer hospital stays in RP patients (P < 0.05).

DISCUSSION

Lung bile is almost universally present in symptomatic patients, and higher concentrations are associated with poorer respiratory outcomes.

Systems Biology and Bile Acid Signalling in Microbiome-Host Interactions in the Cystic Fibrosis Lung

The study of the respiratory microbiota has revealed that the lungs of healthy and diseased individuals harbour distinct microbial communities. Imbalances in these communities can contribute to the pathogenesis of lung disease. How these imbalances occur and establish is largely unknown. This review is focused on the genetically inherited condition of Cystic Fibrosis (CF). Understanding the microbial and host-related factors that govern the establishment of chronic CF lung inflammation and pathogen colonisation is essential. Specifically, dissecting the interplay in the inflammation–pathogen–host axis. Bile acids are important host derived and microbially modified signal molecules that have been detected in CF lungs. These bile acids are associated with inflammation and restructuring of the lung microbiota linked to chronicity. This community remodelling involves a switch in the lung microbiota from a high biodiversity/low pathogen state to a low biodiversity/pathogen-dominated state. Bile acids are particularly associated with the dominance of Proteobacterial pathogens. The ability of bile acids to impact directly on both the lung microbiota and the host response offers a unifying principle underpinning the pathogenesis of CF. The modulating role of bile acids in lung microbiota dysbiosis and inflammation could offer new potential targets for designing innovative therapeutic approaches for respiratory disease.

A bird eye view on cystic fibrosis: An underestimated multifaceted chronic disorder

Cystic fibrosis (CF) is an autosomal recessive disease which involves the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF involves in the inflammatory processes and is considered as a multisystem disorder that is not confined to lungs, but it also affects other vital organs that leads to numerous co-morbidities. The respiratory disorder in the CF results in mortality and morbidity which is characterized by series of serious events involving mucus hypersecretion, microbial infections, airways obstruction, inflammation, destruction of epithelium, tissue remodeling and terminal lung diseases. Mucins are the high molecular weight glycoproteins important for the viscoelastic properties of the mucus, play a significant role in the disease mechanisms. Determining the functional association between the CFTR and mucins might help to identify the putative target for specific therapeutic approach. In fact, furin enzyme which helps in the entry of novel COVID-19 virus into the cell, is upregulated in CF and this can also serve as a potential target for CF treatment. Moreover, the use of nano-formulations for CF treatment is an area of research being widely studied as they have also demonstrated promising outcomes. The in-depth knowledge of non-coding RNAs like miRNAs and lncRNAs and their functional association with CFTR gene expression and mutation can provide a different range of opportunity to identify the promising therapeutic approaches for CF.

Focus on gastroesophageal reflux disease in patients with cystic fibrosis

Gastroesophageal reflux disease (GERD) is a common gastrointestinal disorder in cystic fibrosis (CF), and based on various studies, its prevalence is elevated since childhood. There are several pathogenetic mechanisms on the basis of association between CF and GERD. However, there are no specific guidelines for GERD in CF patients, so diagnosis is based on guidelines performed on patients not affected by CF. The aim of this review is to provide the pathophysiology, diagnostic and therapeutic options, complications, and future directions in the management of GERD patients with CF.

[Abdominal manifestations in cystic fibrosis : Clinical review]

Cystic fibrosis (CF) is the most common fatal autosomal recessive disease in the Caucasian population. A mutation in the cystic fibrosis transmembrane regulator protein (CFTR) gene leads to the production of abnormally viscous mucus and secretions in the lungs of these patients. A similar pathology also occurs in other organs. In the abdomen, among others the gastrointestinal tract, the pancreas, and the hepatobiliary system are affected. The involvement of the pancreas leads to its exocrine and endocrine insufficiency. Hepatic manifestations include hepatic steatosis, focal biliary and multilobular cirrhosis, and portal hypertension. Biliary complications include cholelithiasis, microgallbladder, and sclerosing cholangitis. In the gastrointestinal tract, complications such as the distal intestinal obstruction syndrome, invaginations, chronic constipation, wall thickening, and fibrosis in the colon may occur. An important renal manifestation is nephrolithiasis. With currently rapidly increasing life expectancy of patients with cystic fibrosis, complications of extrapulmonary cystic fibrosis manifestations including hepatic and gastrointestinal malignancy could be an increasing cause of morbidity and mortality of these patients. It is therefore important for radiologists to know and recognize these clinical patterns and to monitor these manifestations in follow-up exams. Previous therapy of extrapulmonary manifestations has been largely symptomatic. Fortunately, the new CFTR modulators seem to represent an effective causal therapeutic approach here.

Protective and regenerative effects of a novel medical device against esophageal mucosal damage using in vitro and ex vivo models

Gastroesophageal reflux disease (GERD) is a common digestive disorder that causes esophagitis and injuries to the esophageal mucosa. GERD symptoms are recurrent during pregnancy and their treatment is focused on lifestyle changes and nonprescription medicines. The aim of this study was to characterize the mechanism of action of a new patented medical device, an oral formulation containing hyaluronic acid, rice extract, and amino acids dispersed in a bioadhesive polymer matrix, by assessing its protective effects in in vitro and ex vivo models of esophageal mucosa damage. Acidic bile salts and pepsin cocktail (BSC) added to CP-A and COLO-680 N esophagus cells were used as an in vitro GERD model to evaluate the binding capacities, anti-inflammatory effects and reparative properties of the investigational product (IP) in comparison to a viscous control. Our results showed that the IP prevents cell permeability and tight junction dysfunction induced by BSC. Furthermore, the IP was also able to down-regulate IL-6 and IL-8 mRNA expression induced by BSC stimulation and to promote tissue repair and wound healing. The results were confirmed by ex vivo experiments in excised rat esophagi through the quantification of Evans Blue permeability assay. These experiments provided evidence that the IP is able to bind to the human esophagus cells, preventing the damage caused by gastroesophageal reflux, showing potential anti-irritative, soothing, and reparative properties.

Direct Lung Sampling Indicates That Established Pathogens Dominate Early Infections in Children with Cystic Fibrosis

Culture and sequencing have produced divergent hypotheses about cystic fibrosis (CF) lung infections. Culturing suggests that CF lungs are uninfected before colonization by a limited group of CF pathogens. Sequencing suggests diverse communities of mostly oral bacteria inhabit lungs early on and diversity decreases as disease progresses. We studied the lung microbiota of CF children using bronchoscopy and sequencing, with measures to reduce contamination. We found no evidence for oral bacterial communities in lung lavages that lacked CF pathogens. Lavage microbial diversity varied widely, but decreases in diversity appeared to be driven by increased CF pathogen abundance, which reduced the signal from contaminants. Streptococcus, Prevotella, and Veillonella DNA was detected in some lavages containing CF pathogens, but DNA from these organisms was vastly exceeded by CF pathogen DNA and was not associated with inflammation. These findings support the hypothesis that established CF pathogens are primarily responsible for CF lung infections.

Pepsin Triggers Neutrophil Migration Across Acid Damaged Lung Epithelium

Pepsin represents a potential biomarker for extraesophageal reflux disease when detected in airways, however a direct role for pepsin in lung dysfunction has not been clearly established. Children experiencing gastroesophageal and extraesophageal reflux are often prescribed proton pump inhibitors (PPIs) to reduce gastric acid associated damage to esophageal and airway mucosa. The potential of pepsin and gastric fluid, from children that were either on or off PPI therapy, to cause inflammation and damage using a human in vitro co-culture model of the airway mucosa was evaluated herein. Exposure of the airway model to acidic solutions caused cellular damage and loss of viability, however, acid alone did not disrupt barrier integrity or instigate neutrophil trans-epithelial migration without pepsin. Gastric fluid from patients on PPI therapy exhibited only a slightly higher pH yet had significantly higher concentrations of pepsin and elicited more barrier disruption and neutrophil trans-epithelial migration compared to gastric fluid from patients off PPIs. Inflammatory and damaging responses observed with gastric fluid from patients on PPIs were largely driven by pepsin. These results indicate the potential for PPI usage to raise concentrations of pepsin in gastric fluid, which may enhance the pathological impact of micro-aspirations in children with extraesophageal reflux.

Gastroesophageal reflux in cystic fibrosis across the age spectrum

Background

Scientific advances have improved longevity in cystic fibrosis (CF) patients and many of these patients can expect to experience age-related gastrointestinal co-morbidities. We aimed to assess the extent to which age might impact gastroesophageal reflux (GER) in patients with CF.

Methods

Our esophageal pH-multichannel intraluminal impedance monitoring database was searched for tracings belonging to CF patients ≥2 years old without prior fundoplication and not taking anti-reflux medications immediately prior (within 7 days) and during the study. Tracings were retrospectively analyzed; Impedance and pH variables were evaluated with respect to age and pulmonary function.

Results

Twenty-eight patients were enrolled; 16 children (3.1-17.7 years) and 12 adults (18.2-48.9 years). Among pH probe parameters, correlation analysis showed DeMeester score (P=0.011) and number of acid reflux events lasting >5 minutes (P=0.047) to be significantly correlated with age. Age was not significantly correlated with any of the impedance parameters. Age was negatively correlated with baseline impedance (BI) in the distal esophagus (r=-0.424, P=0.023) and BI was negatively correlated with several pH parameters, including reflux index (r=-0.553, P=0.002), number of total acid reflux events (r=-0.576, P=0.001), number of acid reflux events lasting >5 minutes (r=-0.534, P=0.003), and DeMeester score (r=-0.510, P=0.006). Pulmonary function (percent predicted forced expiratory volume in one minute; ppFEV₁) was negatively correlated with age (r=-0.494, P=0.0007). The interaction of age and ppFEV₁ and any of the reflux parameters, however, was not significant (P>0.05); the strongest evidence for an interaction was found for the number of acid reflux events reaching the proximal esophagus, but this interaction still did not reach statistical significance (P=0.070).

Conclusions

In a small cohort, we found evidence that age may be associated with increased acid exposure and that both age and increased acid exposure are associated with reduced BI in the distal esophagus. The negative relationship between pulmonary function and age in our cohort is not related to GER. This pilot study supports the need for esophageal assessment and treatment of GER as standard components of clinical care for an aging CF population.

Exposure to Bile Leads to the Emergence of Adaptive Signaling Variants in the Opportunistic Pathogen Pseudomonas aeruginosa

The chronic colonization of the respiratory tract by the opportunistic pathogen Pseudomonas aeruginosa is the primary cause of morbidity and mortality in cystic fibrosis (CF) patients. P. aeruginosa has been shown to undergo extensive genomic adaptation facilitating its persistence within the CF lung allowing it to evade the host immune response and outcompete co-colonizing residents of the lung microbiota. However, whilst several studies have described the various mutations that frequently arise in clinical isolates of P. aeruginosa, the environmental factors governing the emergence of these genetic variants is less well characterized. Gastro-oesophageal reflux has recently emerged as a major co-morbidity in CF and is often associated with the presence of bile acids in the lungs most likely by (micro) aspiration. In order to investigate whether bile may select for genetic variants, P. aeruginosa was experimentally evolved in artificial sputum medium, a synthetic media resembling environmental conditions found within the CF lung. Pigmented derivatives of P. aeruginosa emerged exclusively in the presence of bile. Genome sequencing analysis identified single nucleotide polymorphisms (SNPs) in quorum sensing (lasR) and both the pyocyanin (phzS) and pyomelanin (hmgA) biosynthetic pathways. Phenotypic analysis revealed an altered bile response when compared to the ancestral P. aeruginosa progenitor strain. While the recovered pigmented derivatives retained the bile mediated suppression of swarming motility and enhanced antibiotic tolerance, the biofilm, and redox responses to bile were abolished in the adapted mutants. Though loss of pseudomonas quinolone signal (PQS) production in the pigmented isolates was not linked to the altered biofilm response, the loss of redox repression could be explained by defective alkyl-quinolone (AQ) production in the presence of bile. Collectively, these findings suggest that the adaptive variants of P. aeruginosa that arise following long term bile exposure enables the emergence of ecologically competitive sub-populations. Altered pigmentation and AQ signaling may contribute to an enhancement in fitness facilitating population survival within a bile positive environment.

Pulmonary aspiration in preschool children with cystic fibrosis

Pulmonary aspiration of gastric refluxate (PAGR) has been demonstrated in association with pulmonary inflammation in school aged children with Cystic Fibrosis (CF). We sought to determine if similar findings were present in preschool children. Pepsin was measured in Broncho-alveolar lavage (BAL) fluid collected from clinically stable preschool children with CF and controls. Elevated pepsin levels were found in a subgroup of children with CF, but this was not found to be associated with pulmonary infection, pulmonary inflammation or respiratory or gastrointestinal symptoms.

Cystic Fibrosis and gastroesophageal reflux disease

Gastroesophageal reflux is common in children and adults with cystic fibrosis (CF). Pathological gastroesophageal reflux disease (GERD) is also frequent in patients of all ages with CF. This article reviews the pathophysiology, diagnostic work-up, management options, complications, and future directions in the evaluation and management of GERD - unique to and pertinent for - patients with CF in particular.

Standard (head-down tilt) versus modified (without head-down tilt) postural drainage in infants and young children with cystic fibrosis

BACKGROUND

Postural drainage is used primarily in infants with cystic fibrosis from diagnosis up to the moment when they are mature enough to actively participate in self-administered treatments. However, there is a risk of gastroesophageal reflux associated with this technique.This is an update of a review published in 2015.

OBJECTIVES

To compare the effects of standard postural drainage (15º to 45º head-down tilt) with modified postural drainage (15º to 30º head-up tilt) with regard to gastroesophageal reflux in infants and young children up to six years old with cystic fibrosis in terms of safety and efficacy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register. We also searched the reference lists of relevant articles and reviews. Additional searches were conducted on ClinicalTrials.gov and on the WHO International Clinical Trials Registry Platform for any planned, ongoing and unpublished studies.The date of the most recent literature searches: 19 June 2017.

SELECTION CRITERIA

We included randomised controlled studies that compared two postural drainage regimens (standard and modified postural drainage) with regard to gastroesophageal reflux in infants and young children (up to and including six years old) with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently identified studies for inclusion, extracted outcome data and assessed risk of bias. We resolved disagreements by consensus or by involving a third review author. We contacted study authors to obtain missing or additional information. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

Two studies, involving a total of 40 participants, were eligible for inclusion in the review. We included no new studies in the 2018 update. The included studies were different in terms of the age of participants, the angle of tilt, the reported outcomes, the number of sessions and the study duration. The following outcomes were measured: appearance or exacerbation of gastroesophageal reflux episodes; percentage of peripheral oxygen saturation; number of exacerbations of upper respiratory tract symptoms; number of days on antibiotics for acute exacerbations; chest X-ray scores; and pulmonary function tests. One study reported that postural drainage with a 20° head-down position did not appear to exacerbate gastroesophageal reflux. However, the majority of the reflux episodes in this study reached the upper oesophagus (moderate-quality evidence). The second included study reported that modified postural drainage (30° head-up tilt) was associated with fewer number of gastroesophageal reflux episodes and fewer respiratory complications than standard postural drainage (30° head-down tilt) (moderate-quality evidence). The included studies had an overall low risk of bias. One included study was funded by the Sydney Children's Hospital Foundation and the other by the Royal Children's Hospital Research Foundation and Physiotherapy Research Foundation of Australia. Data were not able to be pooled by meta-analysis due to differences in the statistical presentation of the data.

AUTHORS' CONCLUSIONS

The limited evidence regarding the comparison between the two regimens of postural drainage is still weak due to the small number of included studies, the small number of participants assessed, the inability to perform any meta-analyses and some methodological issues with the studies. However, it may be inferred that the use of a postural regimen with a 30° head-up tilt is associated with a lower number of gastroesophageal reflux episodes and fewer respiratory complications in the long term. The 20° head-down postural drainage position was not found to be significantly different from the 20° head-up tilt modified position. Nevertheless, the fact that the majority of reflux episodes reached the upper oesophagus should make physiotherapists carefully consider their treatment strategy. We do not envisage that there will be any new trials undertaken that will affect the conclusions of this review; therefore, we do not plan to update this review.

Influence of bouncing and assisted autogenic drainage on acid gastro-oesophageal reflux in infants

OBJECTIVES

To determine the influence of modern airway clearance techniques using assisted autogenic drainage (AAD), whether or not combined with bouncing, on acid gastro-oesophageal reflux (GOR) in infants <1 year.

METHODS

In this controlled trial with intra-subject design infants were studied using oesophageal pH monitoring over 24 h, during which they received one 15 min session of bouncing, AAD or bouncing combined with AAD (BAAD). The number of reflux episodes (RE) and the refluxindex (RI) were the outcome measures. The results obtained during (T15) and 15 min after the intervention (T30) were compared to a period of 15 min before treatment (T0).

RESULTS

The results of 150 infants, evenly distributed over the three treatment groups, were analyzed. No significant differences were found in number of RE at T15 and T30 compared to T0 in the bouncing group (P = 0.42), the AAD group (P = 0.14), and the BAAD group (P = 0.91). RI was significantly lower in the AAD group at T15 compared to T0 (P < 0.01). No differences in RI were found in the bouncing group (P = 0.28), nor in the BAAD group (P = 0.81).

CONCLUSION

Bouncing, AAD and BAAD do not induce, nor aggravate acid GOR in infants under the age of 1 year.

The Saudi Thoracic Society guidelines for diagnosis and management of noncystic fibrosis bronchiectasis

This is the first guideline developed by the Saudi Thoracic Society for the diagnosis and management of noncystic fibrosis bronchiectasis. Local experts including pulmonologists, infectious disease specialists, thoracic surgeons, respiratory therapists, and others from adult and pediatric departments provided the best practice evidence recommendations based on the available international and local literature. The main objective of this guideline is to utilize the current published evidence to develop recommendations about management of bronchiectasis suitable to our local health-care system and available resources. We aim to provide clinicians with tools to standardize the diagnosis and management of bronchiectasis. This guideline targets primary care physicians, family medicine practitioners, practicing internists and respiratory physicians, and all other health-care providers involved in the care of the patients with bronchiectasis.

Current and emerging comorbidities in cystic fibrosis

Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed ubiquitously throughout the body. Thus, while respiratory manifestations dominate much of cystic fibrosis (CF) care, there are prominent multi-organ manifestations and comorbidities. In the general population, the number of comorbidities increases with aging. Few illnesses have experienced such a dramatic improvement in survival as CF, which has been transformed from an illness of childhood death to one of adult survival. Hence, as longevity increases in CF, it is paralleled by an increasing number of patients with multicomplex comorbidities availing of care from adult CF multi-disciplinary teams. This review gives an overview of the traditional CF associated comorbidities and those emerging in an aging adult cohort. While historically the treatment of CF focused on the consequences of CFTR dysfunction, the recent advent of CFTR modulators with the potential to enhance CFTR function represents an opportunity to potentially reverse or delay the development of some of the comorbidities associated with CF. Where evidence is available for the impact of CFTR modulatory therapy, namely ivacaftor on comorbidities in CF, this is highlighted.

Influence of intrapulmonary percussive ventilation in upright position on gastro-oesophageal reflux in infants

OBJECTIVES

To determine the influence of physiotherapy using intrapulmonary percussive ventilation on gastro-oesophageal reflux (GOR) in infants <1 year.

METHODS

In this controlled trial with intra-subject design, children were studied using multichannel intraluminal impedance pH (pH-MII) monitoring over 24 hr, during which they received one 20-min session of intrapulmonary percussive ventilation in upright position (IPV_R ), 2 hr after their latest feeding. Two hours after each feeding, the number of reflux episodes (RE) over a 20-min period was registered for each infant and a mean per 20 min was calculated in order to obtain a baseline value. The number of RE during IPV_R intervention was compared to baseline.

RESULTS

Fifty infants with a median age of 133 days were recruited of whom 21 were diagnosed with pathological GOR. During IPV_R , the incidence of RE in the entire group was significantly lower compared to baseline; median (inter-quartile range [IQR]) 0 (0-1) versus 0.71 (0-1.33) RE, respectively, P = 0.003. The subgroup with abnormal GOR showed also a significant decrease of RE during IPV_R ; median (IQR) 0 (0-1) versus 1.17 (0.55-2.16) RE, respectively, P = 0.03. No difference was detected in the group with normal reflux; median (IQR) 0.6 (0-1) compared to 0 (0-1) RE, respectively, P = 0.34.

CONCLUSION

IPV_R does not induce, nor aggravate GOR in infants without and with pathological GOR, respectively, but on the contrary decreases the number of RE in patients with pathological reflux. Pediatr Pulmonol. 2016;51:1065-1071. © 2016 Wiley Periodicals, Inc.

An updated review on gastro-esophageal reflux in pediatrics

Comprehensive guidelines for the diagnosis and management of gastro-esophageal reflux (GER) and GER disease (GERD) were developed by the European and North American Societies for Pediatric Gastroenterology, Hepatology and Nutrition. GERD is reflux associated with troublesome symptoms or complications. The recognition of GER and GERD is relevant to implement best management practices. A conservative management is indicated in infants with uncomplicated physiologic reflux. Children with GERD may benefit from further evaluation and treatment. Since the publications of the European and North American Societies for Pediatric Gastroenterology, Hepatology and Nutrition guidelines in 2009, no important novelties in drug treatment have been reported. Innovations are mainly restricted to the management of regurgitation in infants. During the last 5 years, pros and cons of multichannel intraluminal impedance have been highlighted. However, overall 'not much has changed' in the diagnosis and management of GER and GERD in infants and children.

Enteral tube feeding for individuals with cystic fibrosis: Cystic Fibrosis Foundation evidence-informed guidelines

Nutrition is integral to the care of individuals with cystic fibrosis (CF). Better nutritional status is associated with improved pulmonary function. In some individuals with CF, enteral tube feeding can be useful in achieving optimal nutritional status. Current nutrition guidelines do not include detailed recommendations for enteral tube feeding. The Cystic Fibrosis Foundation convened an expert panel to develop enteral tube feeding recommendations based on a systematic review of the evidence and expert opinion. These guidelines address when to consider enteral tube feeding, assessment of confounding causes of poor nutrition in CF, preparation of the patient for placement of the enteral feeding tube, management of the tube after placement and education about enteral feeding. These recommendations are intended to guide the CF care team, individuals with CF, and their families through the enteral tube feeding process.

Bile signalling promotes chronic respiratory infections and antibiotic tolerance

Despite aggressive antimicrobial therapy, many respiratory pathogens persist in the lung, underpinning the chronic inflammation and eventual lung decline that are characteristic of respiratory disease. Recently, bile acid aspiration has emerged as a major comorbidity associated with a range of lung diseases, shaping the lung microbiome and promoting colonisation by Pseudomonas aeruginosa in Cystic Fibrosis (CF) patients. In order to uncover the molecular mechanism through which bile modulates the respiratory microbiome, a combination of global transcriptomic and phenotypic analyses of the P. aeruginosa response to bile was undertaken. Bile responsive pathways responsible for virulence, adaptive metabolism, and redox control were identified, with macrolide and polymyxin antibiotic tolerance increased significantly in the presence of bile. Bile acids, and chenodeoxycholic acid (CDCA) in particular, elicited chronic biofilm behaviour in P. aeruginosa, while induction of the pro-inflammatory cytokine Interleukin-6 (IL-6) in lung epithelial cells by CDCA was Farnesoid X Receptor (FXR) dependent. Microbiome analysis of paediatric CF sputum samples demonstrated increased colonisation by P. aeruginosa and other Proteobacterial pathogens in bile aspirating compared to non-aspirating patients. Together, these data suggest that bile acid signalling is a leading trigger for the development of chronic phenotypes underlying the pathophysiology of chronic respiratory disease.

Injection laryngoplasty in children with cystic fibrosis and abnormal swallow

OBJECTIVE

Children with cystic fibrosis (CF) are uniquely vulnerable to the pulmonary complications of chronic aspiration. We present a case series of children with CF and evidence of chronic aspiration who underwent injection laryngoplasty to improve the safety and efficacy of their swallow.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care children's hospital.

METHODS/SUBJECTS

A chart review was performed on three consecutive cases of children with CF and evidence of aspiration on modified barium swallow (MBS) evaluated at a tertiary care, academic children's medical center.

RESULTS

Three patients with CF underwent injection laryngoplasty for evidence of aspiration or laryngeal penetration on MBS evaluation. Normal laryngeal anatomy was identified intraoperatively in each case. At the time of the procedure, patients were 22 months, 70 months, and 24 months old, and follow-up information was available for 7 months, 11 months, and 12 months post-procedure, respectively. Presenting symptoms included chronic cough, cough with oral liquids, and recurrent pneumonia. Each patient underwent successful injection into the interarytenoid space. Post-operatively, modified barium swallow demonstrated resolution of aspiration or penetration in all patients. No procedure-related complications were encountered.

CONCLUSION

Patients with CF are highly susceptible to pulmonary infections, and aggressive treatment of chronic aspiration is often necessary. Injection laryngoplasty may be effective in normalizing swallowing in these children. Future study will elucidate the duration of effect and if this technique improves long-term pulmonary outcomes in CF patients.

Influence of respiratory physiotherapy on gastro-oesophageal reflux in infants: A systematic review

PURPOSE

To provide a survey on the literature concerning the influence of respiratory physiotherapy on gastro-oesophageal reflux (GOR) in infants and young children.

METHODS

Electronic databases (Pubmed, Web of Science, PEDro) and reference lists of articles and narrative reviews were searched. Articles were included when infants and small children underwent oesophageal pH monitoring or pH-multichannel intraluminal impedance monitoring while respiratory physiotherapy was administered. Descriptive analysis was performed and two researchers scored the methodological quality of these studies.

RESULTS

Out of 985 articles, seven (six English, one French) have been included, In total 277 patients were involved, 71 with cystic fibrosis. Depending on the technique used, four studies showed GOR to be aggravated during therapy, three studies reported no effect.

CONCLUSION

The evidence is not conclusive on whether respiratory physiotherapy induces or aggravates GOR in infants and small children. Age, disease, and treatment options play an important role. More specific research, also focussing on the influence of respiratory physiotherapy on non-acid reflux and the impact of recently developed airway clearance techniques (ACT's) on GOR is necessary.

Correlation between laryngobronchoscopy and pepsin in the diagnosis of extra-oesophageal reflux

Objective:

This study aimed to investigate pepsin as a marker of extra-oesophageal reflux disease by examining its presence in tracheal aspirates and correlating it with macroscopic changes on laryngobronchoscopy, along with the results of standard tests for gastro-oesophageal reflux disease and clinical features.

Methods:

A retrospective review was undertaken of a cohort of 188 paediatric patients who underwent laryngobronchoscopy at a tertiary children's hospital and for whom pepsin assay results of tracheal aspirates were available. An association analysis was performed.

Results:

The mean patient age was 3.99 (3.40–4.58) years, with a male preponderance (55 per cent). Positive changes on laryngobronchoscopy were significantly associated with positive tracheal pepsin findings (p< 0.0001) but not with positive standard gastro-oesophageal reflux disease investigations. A positive pepsin assay was significantly associated with a history of recurrent croup (p= 0.0385) and a diagnosis of cystic fibrosis (p= 0.0232).

Conclusion:

Macroscopic changes on laryngobronchoscopy were significantly associated with positive tracheal pepsin findings in this paediatric population, suggesting that extra-oesophageal reflux disease may be a contributing aetiology.

Standard (head-down tilt) versus modified (without head-down tilt) postural drainage in infants and young children with cystic fibrosis

BACKGROUND

Postural drainage is used primarily in infants with cystic fibrosis from diagnosis up to the moment when they are mature enough to actively participate in self-administered treatments. However, there is a risk of gastroesophageal reflux associated with this technique.

OBJECTIVES

To compare the effects of standard postural drainage (greater (30° to 45° head-down tilt) and lesser (15° to 20° head-down tilt)) with modified postural drainage (greater (30º head-up tilt) or lesser (15º to 20º head-up tilt)) with regard to gastroesophageal reflux in infants and young children up to six years old with cystic fibrosis in terms of safety and efficacy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register. We also searched the reference lists of relevant articles and reviews. Additional searches were conducted on ClinicalTrials.gov and on the WHO International Clinical Trials Registry Platform for any planned, ongoing and unpublished studies.The date of the most recent literature searches: 20 January 2015.

SELECTION CRITERIA

We included randomised controlled studies that compared two postural drainage regimens (standard and modified postural drainage) with regard to gastroesophageal reflux in infants and young children (up to and including six years old) with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies to be included in the review, assessed their risk of bias and extracted data.

MAIN RESULTS

Two studies, including 40 participants, were eligible for inclusion in the review. The studies were different in terms of the age of participants, the angle of tilt, the reported outcomes, the number of sessions and the study duration. The following outcomes were measured: appearance or exacerbation of gastroesophageal reflux episodes; percentage of peripheral oxygen saturation; number of exacerbations of upper respiratory tract symptoms; number of days on antibiotics for acute exacerbations; chest X-ray scores; and pulmonary function tests. One study reported that postural drainage with a 20° head-down position did not appear to exacerbate gastroesophageal reflux. However, the majority of the reflux episodes reached the upper oesophagus. The second included study reported that modified postural drainage (30º head-up tilt) was associated with fewer number of gastroesophageal reflux episodes and fewer respiratory complications than standard postural drainage (30º head-down tilt). The included studies had an overall low risk of bias. Data were not able to be pooled by meta-analysis due to differences in the statistical presentation of the data.

AUTHORS' CONCLUSIONS

The available evidence regarding the comparison between the two regimens of postural drainage is still weak due to the small number of included studies, the small number of participants assessed, the inability to perform any meta-analyses and some methodological issues with the studies. However, it may be inferred that the use of a postural regimen with a 30° head-up tilt is associated with a lower number of gastroesophageal reflux episodes and fewer respiratory complications in the long term. The 20º head-down postural drainage position was not found to be significantly different from the 20º head-up tilt modified position. Nevertheless, the fact that the majority of reflux episodes reached the upper oesophagus should make physiotherapists carefully consider their treatment strategy.

Bile acids repress hypoxia-inducible factor 1 signaling and modulate the airway immune response

Gastroesophageal reflux (GER) frequently occurs in patients with respiratory disease and is particularly prevalent in patients with cystic fibrosis. GER is a condition in which the duodenogastric contents of the stomach leak into the esophagus, in many cases resulting in aspiration into the respiratory tract. As such, the presence of GER-derived bile acids (BAs) has been confirmed in the bronchoalveolar lavage fluid and sputum of affected patients. We have recently shown that bile causes cystic fibrosis-associated bacterial pathogens to adopt a chronic lifestyle and may constitute a major host trigger underlying respiratory infection. The current study shows that BAs elicit a specific response in humans in which they repress hypoxia-inducible factor 1α (HIF-1α) protein, an emerging master regulator in response to infection and inflammation. HIF-1α repression was shown to occur through the 26S proteasome machinery via the prolyl hydroxylase domain (PHD) pathway. Further analysis of the downstream inflammatory response showed that HIF-1α repression by BAs can significantly modulate the immune response of airway epithelial cells, correlating with a decrease in interleukin-8 (IL-8) production, while IL-6 production was strongly increased. Importantly, the effects of BAs on cytokine production can also be more dominant than the bacterium-mediated effects. However, the effect of BAs on cytokine levels cannot be fully explained by their ability to repress HIF-1α, which is not surprising, given the complexity of the immune regulatory network. The suppression of HIF-1 signaling by bile acids may have a significant influence on the progression and outcome of respiratory disease, and the molecular mechanism underpinning this response warrants further investigation.

Aspirated bile: a major host trigger modulating respiratory pathogen colonisation in cystic fibrosis patients

Chronic respiratory infections are a leading global cause of morbidity and mortality. However, the molecular triggers that cause respiratory pathogens to adopt persistent and often untreatable lifestyles during infection remain largely uncharacterised. Recently, bile aspiration caused by gastro-oesophageal reflux (GOR) has emerged as a significant complication associated with respiratory disease, and cystic fibrosis (CF) in particular. Based on our previous finding that the physiological concentrations of bile influence respiratory pathogens towards a chronic lifestyle in vitro, we investigated the impact of bile aspiration on the lung microbiome of respiratory patients. Sputum samples (n = 25) obtained from a cohort of paediatric CF patients were profiled for the presence of bile acids using high-resolution liquid chromatography-mass spectrometry (LC-MS). Pyrosequencing was performed on a set of ten DNA samples that were isolated from bile aspirating (n = 5) and non-bile aspirating (n = 5) patients. Both denaturing gradient gel electrophoresis (DGGE) and pyrosequencing revealed significantly reduced biodiversity and richness in the sputum samples from bile aspirating patients when compared with non-aspirating patients. Families and genera associated with the pervasive CF microbiome dominated aspirating patients, while bacteria associated with the healthy lung were most abundant in non-aspirating patients. Bile aspiration linked to GOR is emerging as a major host trigger of chronic bacterial infections. The markedly reduced biodiversity and increased colonisation by dominant proteobacterial CF-associated pathogens observed in the sputum of bile aspirating patients suggest that bile may play a major role in disease progression in CF and other respiratory diseases.

Cystic fibrosis: a surgical matter?

BACKGROUND

Gastroesophageal reflux disease (GERD) is very common in patients with chronic lung diseases. We evaluated the incidence of GERD in young patients with cystic fibrosis (CF) and defined the characteristics of gastroesophageal reflux episodes analyzed by pH-multichannel intraluminal impedance (pH-MII) and esophagogastric scintigraphy.

PATIENTS AND METHODS

Since 2010, 31 patients with CF underwent pH-MII. Scintigraphy and upper endoscopy were performed in positive GERD patients. Forced expiratory volume in 1 second (FEV1%) predicted was detected.

RESULTS

pH-MII was positive in 17/31 (54.8%) patients (mean age: 12.4 years; range: 4-17 years). pH monitoring detected an average of 64.6 acid reflux events 4.4 episodes >5 minutes in duration. The DeMeester score was 38.5. Impedance identified a mean number of reflux episodes of 66 (65.2% acid; 32% weakly acidic; 2.8% nonacidic), 28% of which reached the proximal esophagus. Esophageal transit and gastric emptying were delayed in 6/13 (46.1%) and in 5/15 (33.3%) cases, respectively. No differences were found in lung function between positive and negative GERD patients (P=0.88).

CONCLUSIONS

Pediatric patients with CF have a high incidence of GERD with acidic events. These patients should be investigated with pH-MII and scintigraphy in order to make an early diagnosis and determine the most appropriate follow-up.

Children with cystic fibrosis have prolonged chemical clearance of acid reflux compared to symptomatic children without cystic fibrosis

OBJECTIVES

Few studies compare gastroesophageal reflux (GER) parameters of cystic fibrosis (CF) children and symptomatic non-CF children. We aimed to compare the impedance-pH (IMP-pH) parameters for these two groups and to test the hypothesis that prolonged acid exposure in CF patients is due to delayed chemical clearance (CC).

METHODS

IMP-pH tracings from 16 CF children (median 8.2 years) and 16 symptomatic non-CF children (median 8.3 years) were analyzed. Software was used to generate IMP-pH reports and parameter data were extracted. IMP-pH was used to calculate the mean CC for each patient.

RESULTS

pH studies showed no difference in acid GER (AGER) frequency (p = 0.587); however, mean AGER duration, duration of longest AGER, AGER index, and DeMeester scores were all significantly higher for CF patients. IMP showed no difference in GER frequency [neither acidic (p = 0.918) nor non-acidic (p = 0.277)], but total bolus clearance was more efficient in CF patients (p = 0.049). A larger percentage of total GER reached the proximal esophagus in non-CF children (p = 0.039). Analyses of two-phase AGER episodes showed that these events were more acidic (p = 0.003) and the CC phase was significantly prolonged in the CF cohort (p = 0.001).

CONCLUSIONS

Compared to symptomatic non-CF children, CF children do not have more frequent reflux. Actually, they have better bolus clearance efficiency following reflux and may even have better control over the number of GER episodes that reach the proximal esophagus. CC of AGER, however, is significantly prolonged in the CF cohort, likely due to hyperacidity of refluxed gastric contents.

Distribution of early structural lung changes due to cystic fibrosis detected with chest computed tomography

OBJECTIVE

To examine the distribution of early structural lung changes in clinically stable infants and young children with cystic fibrosis using chest computed tomography (CT).

STUDY DESIGN

This cross-sectional study included 62 children aged 1-6 years with volume-controlled volumetric chest CT scans performed under general anesthesia as part of an early surveillance program. Each lobe was scored for presence and extent of bronchiectasis, mucus plugging, and air trapping using a semiquantitative score. The topographic distribution of structural abnormalities was evaluated by comparing the presence and extent of abnormalities in different lung regions and examining relationships between components.

RESULTS

Although bronchiectasis was most common in the right upper lobe, overall changes in lung structure were not more common or more extensive in the upper lobes. Rather, bronchiectasis was more common in the right lung (right lung 0.95, left lung 0.68, P = .003), and mucus plugging (upper 0.41, middle 0.41, lower 0.72, P = .028) and air trapping (upper 0.79, middle 0.48, lower 0.96, P < .001) were more common in the lower lobes. The extents of bronchiectasis (P < .001) and air trapping (P = .011) were greater in the right lung. Scans with bronchiectasis were also more likely to have coexisting mucus plugging (P = .008) and air trapping (P < .001).

CONCLUSION

Early structural lung disease is heterogeneously distributed in the lung. Quantitative scoring tools for studies using chest CT as an end point, and mechanistic studies that seek to better understand the pathogenesis of early cystic fibrosis lung disease, should take account of this differential topographic expression of disease early in life.

Respiratory pathogens adopt a chronic lifestyle in response to bile

Chronic respiratory infections are a major cause of morbidity and mortality, most particularly in Cystic Fibrosis (CF) patients. The recent finding that gastro-esophageal reflux (GER) frequently occurs in CF patients led us to investigate the impact of bile on the behaviour of Pseudomonas aeruginosa and other CF-associated respiratory pathogens. Bile increased biofilm formation, Type Six Secretion, and quorum sensing in P. aeruginosa, all of which are associated with the switch from acute to persistent infection. Furthermore, bile negatively influenced Type Three Secretion and swarming motility in P. aeruginosa, phenotypes associated with acute infection. Bile also modulated biofilm formation in a range of other CF-associated respiratory pathogens, including Burkholderia cepacia and Staphylococcus aureus. Therefore, our results suggest that GER-derived bile may be a host determinant contributing to chronic respiratory infection.

Mechanisms of increased gastroesophageal reflux in patients with cystic fibrosis

OBJECTIVES

Up to 80% of patients with cystic fibrosis (CF) may have increased gastroesophageal reflux (GER). It has been suggested that increased GER is due to low basal lower esophageal sphincter (LES) pressure and a high number of transient LES relaxations (TLESRs). The aim of our study was to reassess the mechanisms of GER in adult CF patients using state of the art upper-gastrointestinal physiology techniques: high-resolution manometry impedance (HRM-MII).

METHODS

We studied 12 CF patients (age 32 range (19-58), 5 males/7 females) and 11 age-matched healthy volunteers (age 27 range (20-36), 4 males /7 females). HRM-MII was performed in a semi-recumbent position for 30 min during fasting and for 2 h after a standard meal (1,000 kcal). We measured total reflux and proximal extent of reflux with impedance; basal LES pressure, TLESRs, and gastroesophageal pressure gradient (GEPG) with HRM.

RESULTS

Basal LES pressure was lower in CF patients compared with healthy controls, both in the pre- and postprandial period (preprandial 13 (7-22) vs. 24 (13-26) mm Hg, P = 0.04; postprandial 10 (8-14) vs. 18 (10-31) mm Hg, P = 0.01) and TLESRs were the main mechanism for reflux both in CF and in controls. We could not find a difference in the number of TLESRs in CF patients compared with healthy (14 (10-20) vs. 13 (10-24), P = not significant). However, reflux during TLESRs was more frequent in CF compared with healthy volunteers (80 (70-95) vs. 42 (20-78) %, P = 0.0058). GEPG during TLESRs was significantly higher in CF than in controls during inspiration (13.5 (9.5-15.8) vs. 7 (4-9.9) mm Hg, P = 0.004). This difference was due to a lower inspiratory intra-thoracic pressure in CF patients (-8.2 (-10.2-(-4.6) vs. -0.08 (-5.7-2.7) mm Hg, P = 0.002). Compared with controls, CF patients had significantly higher number of reflux episodes (13 (6-20) vs. 7 (3-9), P = 0.014) and CF patients also showed a higher proportion of reflux episodes with a high proximal extent compared with healthy volunteers (49 (22-50) vs. 0 (0-17) %, P = 0.0028).

CONCLUSIONS

CF patients have increased GER with a high proximal extent. Although we could not find a higher number of TLESRs in CF, there is a higher proportion of TLESRs associated with reflux. Unlike non-CF GER disease patients (with increased intra-abdominal pressure), reflux during TLESRs in CF is probably due to an increased GEPG mainly generated by a greater inspiratory negative intra-thoracic pressure.

Gastroesophageal reflux in cystic fibrosis: current understandings of mechanisms and management

Cystic fibrosis (CF) is an inherited disease that affects both the lungs and the digestive system in children and adults. Thick mucus fills the gut and blocks lumens of the pancreas and hepatobiliary systems, creating insufficient pancreas function and liver disease. Chronic gastrointestinal (GI) complications, including intestinal obstruction, occur in neonates, and poor digestion and gastroesophageal reflux disease (GERD) in children. Although GI symptoms tend to improve with age, CF and associated GERD eventually create respiratory insufficiency; the only available treatment option at this stage is a bilateral lung transplant, which carries considerable morbidity and mortality. While GERD may reoccur as a complication of lung transplantation, GERD symptoms are often reduced following a fundoplication.

The impact of reflux burden on Pseudomonas positivity in children with cystic fibrosis

OBJECTIVES

Nonacid gastroesophageal reflux (GER), particularly in patients taking acid suppression, has been implicated as a cause of respiratory infections. We hypothesize that children with cystic fibrosis (CF) and a higher nonacid reflux burden have greater rates of Pseudomonas aeruginosa (Pa) infection than patients with a lower reflux burden.

STUDY DESIGN

We reviewed the multichannel intraluminal impedance (pH-MII) tracings of 35 patients with CF between 2003 and 2010. We compared the reflux profiles between those patients who were Pa positive and Pa negative.

RESULTS

The mean age was 13.5 ± 5.8 years. Twenty-seven patients (76%) were Pa positive. Ninety seven percent of patients were taking proton pump inhibitors during pH-MII testing. The mean percentage of time pH was <4 was 8.5 ± 12%. Pa patients had a significantly higher total, acid and proximal nonacid reflux burden (P < 0.009). There was a negative correlation between nonacid reflux burden and FEV1 (r = -0.397, P = 0.03) and between total number of reflux events and FEV1 (r = -0.474, P = 0.009). After adjusting for age and FEV1, total reflux burden remains significantly associated with Pa positivity (P = 0.055).

CONCLUSIONS

Increased reflux burden may predispose patients to Pa infection and worse lung function.