State of progress in treating cystic fibrosis respiratory disease

Use of mucoactive agents in cystic fibrosis: A consensus survey of Italian specialists

Background

The goal of mucoactive therapies in cystic fibrosis (CF) is to enhance sputum clearance and to reduce a progressive decline in lung function over the patient's lifetime. We aimed to investigate the level of consensus among specialists from Italian CF Centers on appropriateness of therapeutic use of dornase alfa (rhDNase) for CF patients.

Method

A consensus on appropriate prescribing in CF mucoactive agents was appraised by an online Delphi method, based on a panel of 27 pulmonologists, coordinated by a Scientific Committee of six experts in medical care of patients with CF.

Results

Full or very high consensus was reached on several issues related to therapeutic use of dornase alfa for CF patients in clinical practice.

Conclusions

The consensus reached on a number of topics regarding use of mucoactive agents in patients with CF can help guide clinicians in daily practice based on expert experience and define the most appropriate therapeutic strategy for the individual patient.

Predictive factors for premature birth and respiratory exacerbation in pregnancies of women with cystic fibrosis

OBJECTIVE

In this present study, the authors evaluated the predictive factors for adverse maternal-fetal outcomes in pregnancies of women with cystic fibrosis (CF). Patients were followed up by a referral center for adults in southern Brazil.

METHODS

This is a retrospective cohort study that used data from electronic medical records regarding pregnancies of women diagnosed with CF.

RESULTS

The study included 39 pregnancies related to 20 different women. The main adverse outcomes were high prevalence rates of premature birth (38.5%) and maternal respiratory exacerbation (84.6%). Lower body mass index (BMI) values (< 20.8) and younger ages of CF diagnosis increased the risk of premature birth. The presence of methicillin-resistant and absence of methicillin-sensitive Staphylococcus aureus, as well as a younger age of diagnosis, increased the risk of maternal respiratory exacerbation during pregnancy.

CONCLUSIONS

Conception in women with CF is often associated with maternal and fetal complications. Continuous monitoring by a multidisciplinary team should emphasize appropriate nutritional status, investigation of bacterial colonization, and immediate attention to respiratory exacerbations.

Identification of novel targets of azithromycin activity against Pseudomonas aeruginosa grown in physiologically relevant media

Pseudomonas aeruginosa causes severe multidrug-resistant infections that often lead to bacteremia and sepsis. Physiologically relevant conditions can increase the susceptibility of pathogens to antibiotics, such as azithromycin (AZM). When compared to minimal-inhibitory concentrations (MICs) in laboratory media, AZM had a 16-fold lower MIC in tissue culture medium with 5% Mueller Hinton broth (MHB) and a 64-fold lower MIC in this tissue culture medium with 20% human serum. AZM also demonstrated increased synergy in combination with synthetic host-defense peptides DJK-5 and IDR-1018 under host-like conditions and in a murine abscess model. To mechanistically study the altered effects of AZM under physiologically relevant conditions, global transcriptional analysis was performed on P. aeruginosa with and without effective concentrations of AZM. This revealed that the arn operon, mediating arabinosaminylation of lipopolysaccharides and related regulatory systems, was down-regulated in host-like media when compared to MHB. Inactivation of genes within the arn operon led to increased susceptibility of P. aeruginosa to AZM and great increases in synergy between AZM and other antimicrobial agents, indicating that dysregulation of the arn operon might explain increased AZM uptake and synergy in host-like media. Furthermore, genes involved in central and energy metabolism and ribosome biogenesis were dysregulated more in physiologically relevant conditions treated with AZM, likely due to general changes in cell physiology as a result of the increased effectiveness of AZM in these conditions. These data suggest that, in addition to the arn operon, there are multiple factors in host-like environments that are responsible for observed changes in susceptibility.

Lumacaftor/ivacaftor in people with cystic fibrosis with an A455E-CFTR mutation

BACKGROUND

Previous in vitro organoid data showed A455E-CFTR, a rare CFTR mutation with 4.1% prevalence in the Netherlands, responds to lumacaftor/ivacaftor (LUM/IVA). We explored LUM/IVA's clinical efficacy in people with CF and ≥1 A455E-CFTR mutation.

METHODS

Participants aged ≥12 years were randomized to 1 of 2 treatment sequences (LUM/IVA→placebo or placebo→LUM/IVA) with an 8-week washout period between. Primary endpoint was absolute change in ppFEV₁ from study baseline through 8 weeks. Additional endpoints were change in sweat chloride concentration (SwCl) and CFQ-R respiratory domain score. Correlations between organoid-based measurements and clinical endpoints were investigated.

RESULTS

Twenty participants were randomized at 2 sites in the Netherlands. Mean absolute change in ppFEV₁ from study baseline through Week 8 showed a treatment difference of 0.1 percentage points (95% CI, -2.5 to 2.7; P = 0.928) between LUM/IVA (within-group mean change, 2.7) and placebo (within-group mean change, 2.6). The mean absolute change in SwCl concentration from study baseline through Week 8 showed a treatment difference of -7.8 mmol/L between LUM/IVA and placebo (P = 0.004), while the absolute change in CFQ-R respiratory domain score showed a treatment difference of 3.5 between LUM/IVA and placebo (P = 0.469). The in vitro organoid-based assay demonstrated a concentration-dependent swelling increase with LUM/IVA. Exploratory correlation analyses between organoid swelling and ppFEV₁ and SwCl outcomes showed correlation coefficients of 0.49 and -0.11, respectively.

CONCLUSIONS

In this exploratory study, LUM/IVA elicited an in vitro response in organoid swelling and in vivo response in SwCl in participants with CF and ≥1 A455E-CFTR mutation. The primary endpoint (ppFEV₁) did not show a statistically significant difference between LUM/IVA and placebo; correlations between in vitro and in vivo responses were not established (NCT03061331).

Inhaled dry powder alginate oligosaccharide in cystic fibrosis: a randomised, double-blind, placebo-controlled, crossover phase 2b study

Background

OligoG is a low molecular-weight alginate oligosaccharide that improves the viscoelastic properties of cystic fibrosis (CF) mucus and disrupts biofilms, thereby potentiating the activity of antimicrobial agents. The efficacy of inhaled OligoG was evaluated in adult patients with CF.

Methods

A randomised, double-blind, placebo-controlled multicentre crossover study was used to demonstrate safety and efficacy of inhaled dry powder OligoG. Subjects were randomly allocated to receive OligoG 1050 mg per day (10 capsules three times daily) or matching placebo for 28 days, with 28-day washout periods following each treatment period. The primary end-point was absolute change in percentage predicted forced expiratory volume in 1 s (FEV₁) at the end of 28-day treatment. The intention-to-treat (ITT) population (n=65) was defined as randomised to treatment with at least one administration of study medication and post-dosing evaluation.

Results

In this study, 90 adult subjects were screened and 65 were randomised. Statistically significant improvement in FEV₁ was not observed in the ITT population. Adverse events included nasopharyngitis, cough and pulmonary exacerbation. The number and proportions of patients with adverse events and serious adverse events were similar between OligoG and placebo group.

Conclusions

Inhalation of OligoG-dry powder over 28 days was safe in adult CF subjects. Statistically significant improvement of FEV₁ was not reached. The planned analyses did not indicate a significant treatment benefit with OligoG compared to placebo. Post hoc exploratory analyses showed subgroup results that indicate that further studies of OligoG in this patient population are justified.

Inhalation of OligoG-DPI over 28 days was shown to be safe in adult CF subjects. Statistically significant improvement of FEV₁ was not reached. Post hoc subgroup analyses support mechanism of action for OligoG and warrant further prospective studies.https://bit.ly/2PHq6Z0

Long-term safety study of colistimethate sodium (Colobreathe®): Findings from the UK Cystic Fibrosis Registry

BACKGROUND

As part of the risk management plan in Europe, a long-term observational study was conducted to monitor the safety of colistimethate sodium dry powder for inhalation (CMS-DPI) compared to other inhaled antibiotics.

METHODS

A cohort of CMS-DPI patients and a matched cohort were identified from the UK Cystic Fibrosis Registry (UKCFR) from 2014-2018. The primary outcome was a composite endpoint, defined as adverse events (AEs) or new cystic fibrosis (CF) complications. Other outcomes included pulmonary exacerbations and treatment discontinuations.

RESULTS

Of 1466 and 3503 patients in the CMS-DPI and comparator cohorts, respectively, 82.7% and 79.4% had AEs. Among the most common new CF complications were osteopenia, CF-related diabetes, and increased liver enzymes. The adjusted event rate ratio (ERR) for the primary outcome was 1.25 (95% confidence interval [CI]: 1.18-1.33, p<0.001). After excluding new CF complications, there was no difference between cohorts (ERR=1.04, 95% CI: 0.79-1.38, p=0.785). Pulmonary exacerbations were common in CMS-DPI and comparator cohorts (78.0% and 79.9% of patients, respectively), with adjusted ERR of 1.02 (95% CI: 0.95-1.10, p=0.523). Rates of discontinuation were similar in the CMS-DPI and Tobramycin inhalation powder comparator cohorts (37.8% and 39.8% of patients, respectively).

CONCLUSIONS

There was no difference in the rate of adverse events between CMS-DPI and comparator cohorts. The safety profile of CMS-DPI is similar to those of other inhaled antibiotics, supporting its long-term safety in people with CF. The UKCFR has developed a successful model for partnership with industry to conduct long-term studies aimed at assessing drug safety.

In Vitro Activity of a Novel Glycopolymer against Biofilms of Burkholderia cepacia Complex Cystic Fibrosis Clinical Isolates

Burkholderia cepacia complex (Bcc) lung infections in cystic fibrosis (CF) patients are often associated with a steady decline in lung function and death. The formation of biofilms and inherent multidrug resistance are virulence factors associated with Bcc infection and contribute to increased risk of mortality in CF patients. New therapeutic strategies targeting bacterial biofilms are anticipated to enhance antibiotic penetration and facilitate resolution of infection. Poly (acetyl, arginyl) glucosamine (PAAG) is a cationic glycopolymer therapeutic being developed to directly target biofilm integrity. In this study, 13 isolates from 7 species were examined, including Burkholderia multivorans, Burkholderia cenocepacia, Burkholderia gladioli, Burkholderia dolosa, Burkholderia vietnamiensis, and B. cepacia These isolates were selected for their resistance to standard clinical antibiotics and their ability to form biofilms in vitro Biofilm biomass was quantitated using static tissue culture plate (TCP) biofilm methods and a minimum biofilm eradication concentration (MBEC) assay. Confocal laser scanning microscopy (CLSM) visualized biofilm removal by PAAG during treatment. Both TCP and MBEC methods demonstrated a significant dose-dependent relationship with regard to biofilm removal by 50 to 200 μg/ml PAAG following a 1-h treatment (P < 0.01). A significant reduction in biofilm thickness was observed following a 10-min treatment of Bcc biofilms with PAAG compared to that with vehicle control (P < 0.001) in TCP, MBEC, and CLSM analyses. PAAG also rapidly permeabilizes bacteria within the first 10 min of treatment. Glycopolymers, such as PAAG, are a new class of large-molecule therapeutics that support the treatment of recalcitrant Bcc biofilm.

Results of the Andalusian Cystic Fibrosis Neonatal Screening Program, 5 Years After Implementation

INTRODUCTION

Cystic fibrosis neonatal screening (CFNS), based on double determination of immunoreactive trypsinogen ([IRT] [IRT1/IRT2]), has been available in Andalusia since May 2011. If screening is positive, a sweat test is performed, and if that is positive or inconclusive, genetic testing is requested.

OBJECTIVE

To analyze CFNS, based on results from the first 4.5 years of the program.

MATERIALS AND METHODS

Prospective descriptive study of neonates undergoing CFNS. IRT levels, sweat chloride, and mutations were recorded. Statistical analysis was performed using SPSS 12.0.

RESULTS

Between May 2011 and December 2016, 474,953 neonates underwent CFNS. Of these, 1,087 (0.23%) had elevated IRT2. Since CFNS was introduced, 73 cases of cystic fibrosis were diagnosed; 60 were diagnosed by positive CFNS, and 13 were diagnosed by other means. In one case, the patient developed a typical clinical picture of cystic fibrosis, but had not undergone CFNS at the decision of the parents; the remaining 12 had a negative CFNS (false negatives). Of these, one patient was diagnosed before symptoms developed, as his twin brother had a positive CFNS result; another had chloride at the upper limit of normal, and was subsequently diagnosed with genetic testing before symptoms appeared; and 10 patients developed clinical signs and symptoms. Excluding patients with meconium ileus, sensitivity and specificity of the CFNS program were 85.71% and 99.78%, respectively. The incidence of the disease in Andalusia is 1/6,506 live births.

CONCLUSION

These results are a basis for reflection on possible areas for improvement of the CFNS algorithm, and thought may be given to the introduction of genetic studies to increase sensitivity and reduce false positives.

Correlation between parameters of volumetric capnography and spirometry during a submaximal exercise protocol on a treadmill in patients with cystic fibrosis and healthy controls

INTRODUCTION

Spirometry is the most frequently used test to evaluate the progression of lung damage in cystic fibrosis (CF). However, there has been low sensitivity in detecting early lung changes. In this context, our objective was to identify the correlation between parameters of volumetric capnography (VCap) and spirometric parameters during a submaximal treadmill exercise test.

METHODS

A cross-sectional and controlled study which included 64 patients with CF (CFG) and 64 healthy control subjects (CG) was performed. The CFG was from a university hospital and the CG from local schools. All participants underwent spirometry and VCap before, during and after the submaximal treadmill exercise test. The main variable analyzed by VCap was the slope of phase 3 (slope 3), which indicates the [exhaled carbon dioxide] at the end of expiration, and expresses the heterogeneity of gas emptying in pulmonary periphery. The correlation analysis between spirometry and VCap was conducted using the Spearman correlation test, considering α=0.05.

RESULTS

The indices analyzed by VCap showed correlation with parameters of VCap. Slope 3 showed an inverse correlation with forced expiratory volume in the first second of forced vital capacity (FEV₁) in both groups and at all moments of the submaximal treadmill exercise test. Forced vital capacity (FVC) and FEV₁/FVC ratio showed an inverse correlation with slope 3 only for CFG. Values of slope 3 corrected by the spontaneous tidal volume (VT) and end-tidal carbon dioxide tension (PetCO₂) showed results similar to slope 3 analyzed separately.

CONCLUSION

Parameters of VCap such as slope 3, slope 3/VT and slope 3/PetCO₂ correlated with sensitive variables of spirometry such as FEV₁, FVC and FEV₁/FVC ratio. For the evaluated variables, there was consistency in the correlation between the two tests, which may indicate the impact of CF on pulmonary physiology.

Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants

Pseudomonas aeruginosa is a phenotypically and genotypically diverse and adaptable Gram-negative bacterium ubiquitous in human environments. P. aeruginosa is able to form biofilms, develop antibiotic resistance, produce virulence factors, and rapidly evolve in the course of a chronic infection. Thus P. aeruginosa can cause both acute and chronic, difficult to treat infections, resulting in significant morbidity in certain patient populations. P. aeruginosa strain PA14 is a human clinical isolate with a conserved genome structure that infects a variety of mammalian and nonvertebrate hosts making PA14 an attractive strain for studying this pathogen. In 2006, a nonredundant transposon insertion mutant library containing 5,459 mutants corresponding to 4,596 predicted PA14 genes was generated. Since then, distribution of the PA14 library has allowed the research community to better understand the function of individual genes and complex pathways of P. aeruginosa. Maintenance of library integrity through the replication process requires proper handling and precise techniques. To that end, this manuscript presents protocols that describe in detail the steps involved in library replication, library quality control and proper storage of individual mutants.

Brazilian guidelines for the diagnosis and treatment of cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disorder characterized by dysfunction of the CFTR gene. It is a multisystem disease that most often affects White individuals. In recent decades, various advances in the diagnosis and treatment of CF have drastically changed the scenario, resulting in a significant increase in survival and quality of life. In Brazil, the current neonatal screening program for CF has broad coverage, and most of the Brazilian states have referral centers for the follow-up of individuals with the disease. Previously, CF was limited to the pediatric age group. However, an increase in the number of adult CF patients has been observed, because of the greater number of individuals being diagnosed with atypical forms (with milder phenotypic expression) and because of the increase in life expectancy provided by the new treatments. However, there is still great heterogeneity among the different regions of Brazil in terms of the access of CF patients to diagnostic and therapeutic methods. The objective of these guidelines was to aggregate the main scientific evidence to guide the management of these patients. A group of 18 CF specialists devised 82 relevant clinical questions, divided into five categories: characteristics of a referral center; diagnosis; treatment of respiratory disease; gastrointestinal and nutritional treatment; and other aspects. Various professionals working in the area of CF in Brazil were invited to answer the questions devised by the coordinators. We used the PubMed database to search the available literature based on keywords, in order to find the best answers to these questions.

Immunonutrition in patients with cyctic fibrosis leads to drop of serum amyloid A and increase of oxidative stress

The aim of the present study is to evaluate of the impact of immunonutrition on parameters of oxidative stress and inflammation in patients with cystic fibrosis and malnutrition. In the 30 patients with cystic fibrosis and long-term enteral nutrition support for malnutrition the effect of standard and immunonutrion sipping on oxidative stress and inflammatory activity parameters was compared. Malonyldialdehyde (MDA) as parameter of oxidative stress and serum amyloid A (SAA), interleukin 1 and 6, hsCRP, IgM, IgA, IgG as parameters of inflammatory activity were examined. Immunonutrition decreased SAA to 17.6 mg/L comparing to 25.6 mg/L when standard nutrition was given (p = 0.014). MDA was 0.66 µM on standard and 0.96 µM on immunonutrition support (p<0.01). The significant negative correlation was recorded between MDA and SAA, hs-CRP, interleukin 6, IgA and IgG. In conclusion, the application of immunonutrition in patients with cystic fibrosis and malnutrition is associated with drop of SAA but with the rise of MDA.

Common clinical features of CF (respiratory disease and exocrine pancreatic insufficiency)

First described as a disease of the pancreas, cystic fibrosis is a genetically inherited progressive disease affecting multiple organ systems. Pulmonary and pancreatic involvement is common in individuals with cystic fibrosis, and the former is attributable to most of the mortality that occurs with the condition. This chapter provides an overview of a clinical approach to the pulmonary and pancreatic manifestations of cystic fibrosis.

Cystic Fibrosis and the Nervous System

Cystic fibrosis (CF) is a life-shortening autosomal recessive disorder caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is an anion channel that conducts bicarbonate and chloride across cell membranes. Although defective anion transport across epithelial cells is accepted as the basic defect in CF, many of the features observed in people with CF and organs affected by CF are modulated by the nervous system. This is of interest because CFTR expression has been reported in both the peripheral and central nervous systems, and it is well known that the transport of anions, such as chloride, greatly modulates neuronal excitability. Thus it is predicted that in CF, lack of CFTR in the nervous system affects neuronal function. Consistent with this prediction, several nervous system abnormalities and nervous system disorders have been described in people with CF and in animal models of CF. The goal of this special feature article is to highlight the expression and function of CFTR in the nervous system. Special emphasis is placed on nervous system abnormalities described in people with CF and in animal models of CF. Finally, features of CF that may be modulated by or attributed to faulty nervous system function are discussed.

Pseudomonas aeruginosa Lifestyle: A Paradigm for Adaptation, Survival, and Persistence

Pseudomonas aeruginosa is an opportunistic pathogen affecting immunocompromised patients. It is known as the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and as one of the leading causes of nosocomial infections. Due to a range of mechanisms for adaptation, survival and resistance to multiple classes of antibiotics, infections by P. aeruginosa strains can be life-threatening and it is emerging worldwide as public health threat. This review highlights the diversity of mechanisms by which P. aeruginosa promotes its survival and persistence in various environments and particularly at different stages of pathogenesis. We will review the importance and complexity of regulatory networks and genotypic-phenotypic variations known as adaptive radiation by which P. aeruginosa adjusts physiological processes for adaptation and survival in response to environmental cues and stresses. Accordingly, we will review the central regulatory role of quorum sensing and signaling systems by nucleotide-based second messengers resulting in different lifestyles of P. aeruginosa. Furthermore, various regulatory proteins will be discussed which form a plethora of controlling systems acting at transcriptional level for timely expression of genes enabling rapid responses to external stimuli and unfavorable conditions. Antibiotic resistance is a natural trait for P. aeruginosa and multiple mechanisms underlying different forms of antibiotic resistance will be discussed here. The importance of each mechanism in conferring resistance to various antipseudomonal antibiotics and their prevalence in clinical strains will be described. The underlying principles for acquiring resistance leading pan-drug resistant strains will be summarized. A future outlook emphasizes the need for collaborative international multidisciplinary efforts to translate current knowledge into strategies to prevent and treat P. aeruginosa infections while reducing the rate of antibiotic resistance and avoiding the spreading of resistant strains.

Calcifediol-loaded liposomes for local treatment of pulmonary bacterial infections

The influence of vitamin D3 and its metabolites calcifediol (25(OH)D) and calcitriol on immune regulation and inflammation is well described, and raises the question of potential benefit against bacterial infections. In the current study, 25(OH)D was encapsulated in liposomes to enable aerosolisation, and tested for the ability to prevent pulmonary infection by Pseudomonas aeruginosa. Prepared 25(OH)D-loaded liposomes were nanosized and monodisperse, with a negative surface charge and a 25(OH)D entrapment efficiency of approximately 23%. Jet nebulisation of liposomes was seen to yield an aerosol suitable for tracheo-bronchial deposition. Interestingly, 25(OH)D in either liposomes or ethanolic solution had no effect on the release of the proinflammatory cytokine KC from Pseudomonas-infected murine epithelial cells (LA-4); treatment of infected, human bronchial 16-HBE cells with 25(OH)D liposomes however resulted in a significant reduction in bacterial survival. Together with the importance of selecting an application-appropriate in vitro model, the current study illustrates the feasibility and practicality of employing liposomes as a means to achieve 25(OH)D lung deposition. 25(OH)D-loaded liposomes further demonstrated promising effects regarding prevention of Pseudomonas infection in human bronchial epithelial cells.

Respiratory therapy: a problem among children and adolescents with cystic fibrosis

Objective

: To evaluate the level of self-reported adherence to physical therapy recommendations in pediatric patients (6-17 years) with cystic fibrosis (CF) and to ascertain whether the different levels of adherence correlate with pulmonary function, clinical aspects, and quality of life.

Methods

: This was a cross-sectional study. The patients and their legal guardians completed a questionnaire regarding adherence to physical therapy recommendations and a CF quality of life questionnaire. We collected demographic, spirometric, and bacteriological data, as well as recording the frequency of hospitalizations and Shwachman-Kulczycki (S-K) clinical scores.

Results

: We included 66 patients in the study. Mean age, FEV₁ (% of predicted), and BMI were 12.2 ± 3.2 years, 90 ± 24%, and 18.3 ± 2.5 kg/m², respectively. The patients were divided into two groups: high-adherence (n = 39) and moderate/poor-adherence (n = 27). No statistically significant differences were found between the groups regarding age, gender, family income, and total S-K clinical scores. There were statistically significant differences between the high-adherence group and the moderate/poor-adherence group, the latter showing lower scores for the "radiological findings" domain of the S-K clinical score (p = 0.030), a greater number of hospitalizations (p = 0.004), and more days of hospitalization in the last year (p = 0.012), as well as lower scores for the quality of life questionnaire domains emotion (p = 0.002), physical (p = 0.019), treatment burden (p < 0.001), health perceptions (p = 0.036), social (p = 0.039), and respiratory (p = 0.048).

Conclusions

: Low self-reported adherence to physical therapy recommendations was associated with worse radiological findings, a greater number of hospitalizations, and decreased quality of life in pediatric CF patients.

Activity of Cysteamine against the Cystic Fibrosis Pathogen Burkholderia cepacia Complex

There are no wholly successful chemotherapeutic strategies against Burkholderia cepacia complex (BCC) colonization in cystic fibrosis (CF). We assessed the impact of cysteamine (Lynovex) in combination with standard-of-care CF antibiotics in vitro against BCC CF isolates by the concentration at which 100% of bacteria were killed (MIC₁₀₀) and checkerboard assays under CLSI standard conditions. Cysteamine facilitated the aminoglycoside-, fluoroquinolone- and folate pathway inhibitor-mediated killing of BCC organisms that were otherwise resistant or intermediately sensitive to these antibiotic classes. Slow-growing BCC strains are often recalcitrant to treatment and form biofilms. In assessing the impact of cysteamine on biofilms, we demonstrated inhibition of BCC biofilm formation at sub-MIC₁₀₀s of cysteamine.

In vitro and in vivo evidence for an inflammatory role of the calcium channel TRPV4 in lung epithelium: Potential involvement in cystic fibrosis

Cystic fibrosis (CF) is an inherited disease associated with chronic severe lung inflammation, leading to premature death. To develop innovative anti-inflammatory treatments, we need to characterize new cellular and molecular components contributing to the mechanisms of lung inflammation. Here, we focused on the potential role of "transient receptor potential vanilloid-4" (TRPV4), a nonselective calcium channel. We used both in vitro and in vivo approaches to demonstrate that TRPV4 expressed in airway epithelial cells triggers the secretion of major proinflammatory mediators such as chemokines and biologically active lipids, as well as a neutrophil recruitment in lung tissues. We characterized the contribution of cytosolic phospholipase A2, MAPKs, and NF-κB in TRPV4-dependent signaling. We also showed that 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids, i.e., four natural lipid-based TRPV4 agonists, are present in expectorations of CF patients. Also, TRPV4-induced calcium mobilization and inflammatory responses were enhanced in cystic fibrosis transmembrane conductance regulator-deficient cellular and animal models, suggesting that TRPV4 is a promising target for the development of new anti-inflammatory treatments for diseases such as CF.

Attitudes Toward Discussing Approved and Investigational Treatments for Cystic Fibrosis in Prenatal Genetic Counseling Practice

This project aimed to explore the attitudes of prenatal genetic counselors toward discussion of novel approved and experimental CF treatments in the prenatal setting, and to assess how knowledge of genotype-specific, targeted treatments may influence their current practices. Targeted treatments have the potential to impact the health-related quality of life of individuals affected with CF and therefore, knowledge of the availability of such treatments may influence the decision-making process of parents who receive a fetal diagnosis of CF. Using the 2012 FDA approval and introduction of ivacaftor into CF clinical practice as a case study, a survey was designed to explore the opinions and practices of prenatal genetic counselors with regard to counseling for a prenatal diagnosis of CF, and how those practices might be impacted by the availability of a new genotype-specific treatment. Approximately 800 genetic counselors were sent questionnaires in January of 2013. Respondents were provided information about this treatment and were asked to rate its perceived benefits, along with the likelihood that they would discuss potential benefits and limitations with parents receiving a prenatal diagnosis of CF. One-hundred sixty-nine prenatal genetic counselors (21.1 %) responded to the survey. Results indicated that 80 % of respondents 'never heard of the drug', or they were 'not exactly sure' what it was. After reading the materials provided, counselors felt the new treatment would have 'some' or a 'significant' impact on an affected individual's life. Their opinions varied on what information about this treatment they would choose to discuss with their patients; even if the treatment is currently FDA approved and clinically available for affected individuals with the genotype of the fetus. However, they would 'definitely' refer these patients to a specialist to discuss targeted treatments further. Most prenatal genetic counselors indicated there are certain scenarios in the prenatal setting which warrant a discussion of targeted treatments for CF, at least on some level. Counselor's views on sharing information about new treatment options are shaped by their familiarity with the treatment and their perception of its benefits and limitations, their comfort discussing these subjects, and their interpretation of the genetic counselor's role. Most genetic counselors had never heard of ivacaftor or Kalydeco™ prior to taking the survey. Therefore, counselors need to be better educated about the availability of CFTR mutation-based treatments before they will be able to incorporate discussion of new treatment options into their counseling.

Epigenetic dysregulation of interleukin 8 (CXCL8) hypersecretion in cystic fibrosis airway epithelial cells

Airway epithelial cells in cystic fibrosis (CF) overexpress Interleukin 8 (CXCL8) through poorly defined mechanisms. CXCL8 transcription is dependent on coordinated binding of CCAAT/enhancer binding protein (C/EBP)β, nuclear factor (NF)-κB, and activator protein (AP)-1 to the promoter. Here we show abnormal epigenetic regulation is responsible for CXCL8 overexpression in CF cells. Under basal conditions CF cells had increased bromodomain (Brd)3 and Brd4 recruitment and enhanced NF-κB and C/EBPβ binding to the CXCL8 promoter compared to non-CF cells due to trimethylation of histone H3 at lysine 4 (H3K4me3) and DNA hypomethylation at CpG6. IL-1β increased NF-κB, C/EBPβ and Brd4 binding. Furthermore, inhibitors of bromodomain and extra-terminal domain family (BET) proteins reduced CXCL8 production in CF cells suggesting a therapeutic target for the BET pathway.

[Therapeutic advances in cystic fibrosis in 2014]

Twenty-five years after the cystic fibrosis (CF) gene identification, this discovery actually begins to benefit to patients. Increasing our knowledge on CFTR biology, as well as technical progress made in order to screen for new drugs have made therapeutic strategies move an important step forward. It is likely that in the forthcoming years, the panel of molecules available for CF patients will be larger, with new activators and potentiators. The disease by itself may consequently change in its natural history. CF is an example of the so-called personalized medicine, aiming to fit treatment according to patient's genetic background. Ongoing clinical trials may enlarge the actually limited eligible number of CF patients for new drugs such as ivacaftor. Beyond this exciting and promising new therapeutic approach, one may not push symptomatic treatments on the side. Improvements have been made for inhaled antibiotics administration, aiming to simplify patient's life; clinical trials using new molecules able to liquefy mucus or with anti-inflammatory properties are actually underway. One important next step in the care for CF will be to design and conduct early intervention trials in CF infants. Newborn screening program have been widely implanted around the word, and cohorts studies have shown that both functional and structural abnormalities occurred very early, making the therapeutic window of opportunity tight.

Implementation of newborn screening for cystic fibrosis in Norway. Results from the first three years

BACKGROUND

Norway introduced newborn screening for cystic fibrosis (CF) March 1, 2012. We present results from the first three years of the national newborn CF screening program.

METHODS

Positive primary screening of immunoreactive trypsinogen (IRT) was followed by DNA testing of the Cystic fibrosis transmembrane conductance regulator (CFTR) gene. Infants with two CFTR mutations were reported for diagnostic follow-up.

RESULTS

Of 181,859 infants tested, 1454 samples (0.80%) were assessed for CFTR mutations. Forty children (1:4546) had two CFTR mutations, of which only 21 (1:8660) were confirmed to have a CF diagnosis. The CFTR mutations differed from previously clinically diagnosed CF patients, and p.R117H outnumbered p.F508del as the most frequent mutation. One child with a negative IRT screening test was later clinically diagnosed with CF.

CONCLUSIONS

The CF screening program identified fewer children with a conclusive CF diagnosis than expected. Our data suggest a revision of the IRT/DNA protocol.

[Cystic fibrosis and associated complications]

Cystic fibrosis (CF) is an autosomal recessive inherited metabolic disease. The mutation is located on the long arm of chromosome 7. Due to a defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, chloride ion transport is reduced across the cell membrane. As a result, the disease can be described as an exocrinopathy. In all organs with exocrine glands, disorders occur in association with the defective chloride transport. The main impact of this defect is manifested in the lungs. Therefore, the most common cause of death is pulmonary disease with respiratory insufficiency due to recurrent infections. Unfortunately, a cure for the disease is still not available. However, new therapies that may affect the CFTR mutation more specifically give new hope for better therapeutic options in the future. The long-term goal of therapy is to develop a causal therapy for all six different mutation classes and thus for about 2000 mutations.

Ventilatory abnormalities in patients with cystic fibrosis undergoing the submaximal treadmill exercise test

Background

Exercise has been studied as a prognostic marker for patients with cystic fibrosis (CF), as well as a tool for improving their quality of life and analyzing lung disease. In this context, the aim of the present study was to evaluate and compare variables of lung functioning. Our data included: (i) volumetric capnography (VCAP) parameters: expiratory minute volume (VE), volume of exhaled carbon dioxide (VCO₂), VE/VCO₂, ratio of dead space to tidal volume (VD/VT), and end-tidal carbon dioxide (PetCO₂); (ii) spirometry parameters: forced vital capacity (FVC), percent forced expiratory volume in the first second of the FVC (FEV₁%), and FEV₁/FVC%; and (iii) cardiorespiratory parameters: heart rate (HR), respiratory rate, oxygen saturation (SpO₂), and Borg scale rating at rest and during exercise. The subjects comprised children, adolescents, and young adults aged 6–25 years with CF (CF group [CFG]) and without CF (control group [CG]).

Methods

This was a clinical, prospective, controlled study involving 128 male and female patients (64 with CF) of a university hospital. All patients underwent treadmill exercise tests and provided informed consent after study approval by the institutional ethics committee. Linear regression, Kruskal–Wallis test, and Mann–Whitney test were performed to compare the CFG and CG. The α value was set at 0.05.

Results

Patients in the CFG showed significantly different VCAP values and spirometry variables throughout the exercise test. Before, during, and after exercise, several variables were different between the two groups; statistically significant differences were seen in the spirometry parameters, SpO₂, HR, VCO₂, VE/VCO₂, PetCO₂, and Borg scale rating. VCAP variables changed at each time point analyzed during the exercise test in both groups.

Conclusion

VCAP can be used to analyze ventilatory parameters during exercise. All cardiorespiratory, spirometry, and VCAP variables differed between patients in the CFG and CG before, during, and after exercise.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0056-5) contains supplementary material, which is available to authorized users.

Free DNA in cystic fibrosis airway fluids correlates with airflow obstruction

Chronic obstructive lung disease determines morbidity and mortality of patients with cystic fibrosis (CF). CF airways are characterized by a nonresolving neutrophilic inflammation. After pathogen contact or prolonged activation, neutrophils release DNA fibres decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). NETs have been described to act in a beneficial way for innate host defense by bactericidal, fungicidal, and virucidal actions. On the other hand, excessive NET formation has been linked to the pathogenesis of autoinflammatory and autoimmune disease conditions. We quantified free DNA structures characteristic of NETs in airway fluids of CF patients and a mouse model with CF-like lung disease. Free DNA levels correlated with airflow obstruction, fungal colonization, and CXC chemokine levels in CF patients and CF-like mice. When viewed in combination, our results demonstrate that neutrophilic inflammation in CF airways is associated with abundant free DNA characteristic for NETosis, and suggest that free DNA may be implicated in lung function decline in patients with CF.

Cystic Fibrosis Treatment: A Paradigm for New Pediatric Medicines, Globalization of Drug Development and the Role of the European Medicines Agency

The European Pediatric Pharmaceutical Legislation wants children to benefit more from pharmaceutical progress. In rare diseases, concerns have been raised that this legislation might damage research and stymie drug development. We discuss the role of the European Medicines Agency (EMA) and its Pediatric Committee (PDCO) in the development of ivacaftor, first-in-class for cystic fibrosis (CF) patients with the G551D mutation (and eight other mutations later) and of lumacaftor and ataluren, two more potential break-through CF medications. Ivacaftor was USA-approved early 2012 and six months later in the EU. Registration was based on the same data. We analyzed these drugs' EU pediatric investigation plans (PIPs) and compared the PIP-studies with the pediatric CF studies listed in www.clinicaltrials.gov. The ivacaftor PIP studies appear to reflect what the developer planned anyway, apart from a study in 1-23-month-olds, which has not yet started. The total negotiation time for the current PIP version was approximately 5.5 years. For companies that develop drugs in pediatric diseases, e.g., CF, PIPs represent considerable additional procedural workload with minimal or no additional benefit for the patients. New drugs for pediatric diseases should not be hampered by additional, unnecessary and costly bureaucracy, but be registered as rapidly as possible without compromising safety.

Management of pulmonary exacerbations in cystic fibrosis: still an unmet medical need in clinical practice

Pulmonary exacerbation (PEx) is a hallmark of cystic fibrosis. Although several criteria have been proposed for the definition of PEx, no consensus has yet been reached. Very often, many PEx cases go unreported. A standardized and validated definition is needed to reduce variability in clinical practice. The pathophysiology of recurrent episodes remains unclear, and both onset and risk are multifactorial. PEx leads to increased healthcare costs, impaired quality of life and a cycle in which PEx causes loss of lung function, which predisposes to further episodes. The number of episodes affects survival. Although early diagnosis and aggressive treatment are highly recommended, measures to prevent the emergence of new PEx are even more important. In particular, inhaled antibiotics administered under new treatment schedules could play a key role in preventing exacerbations and thus delay decline in lung function and reduce mortality. The primary objective is zero exacerbations.

Direct interactions between ENaC gamma subunit and ClCN2 in cystic fibrosis epithelial cells

Cystic fibrosis (CF) is a lethal disease caused by mutations in the chloride channel CFTR gene. The disease is characterized by decreased chloride secretion and unregulated sodium absorption through the epithelial sodium channel (ENaC) in the airway epithelium and other affected organs. We hypothesize that a non‐CFTR alternative chloride channel ClCN2 can be activated to negatively regulate ENaC in CF epithelial cell cultures. We identified a novel interaction between ClCN2 and the ENaCγ subunit in CF airway epithelial cells and show that the upregulation of ClCN2 leads to decreased expression of ENaCγ via a K63 ubiquitination mechanism. These regulatory effects of ClCN2 on ENaCγ appear to be dependent on the CBS‐1 domain located within the c‐terminus of ClCN2, which is necessary for the targeting of ClCN2 to the apical surface. In sum, these results suggest the ability of ClCN2 to negatively regulate sodium absorption through ENaC, supporting its role as a therapeutic target for the treatment of CF.

Cystic Fibrosis is caused by mutations in the chloride channel CFTR gene which secondarily increases sodium reabsorption in the airways. ClCN2 is an epithelial chloride channel in the airways that can be activated in CF. We show an interaction between ClCN2 and the epithelial sodium channel subunit gamma that affects subunit expression and targeting to the plasma membrane.

Local modulation of cystic fibrosis conductance regulator: cytoskeleton and compartmentalized cAMP signalling

The cystic fibrosis conductance regulator (CFTR) is a cAMP-regulated Cl(-) channel expressed predominantly at the apical membrane of secreting epithelial cells. Mutations in the CFTR gene lead to cystic fibrosis, the most frequent genetic disease in the Caucasian population. The most common mutation, a deletion of phenylalanine at position 508 (F508del), impairs CFTR folding and chloride channel function. Although an intense effort is under way to identify compounds that target the F508del CFTR structural defect and promote its expression and stability at the plasma membrane, so far their clinical efficacy has proven to be poor, highlighting the necessity to better understand the molecular mechanism of CFTR regulation and of the pathogenesis of the disease. Accumulating evidence suggests that the inclusion of the CFTR in macromolecular complexes and its interaction with the cortical cytoskeleton may play a key role in fine-tuning the regulation of channel function. Here we review some recent findings that support a critical role for protein-protein interactions involving CFTR and for the cytoskeleton in promoting local control of channel activity. These findings indicate that compounds that rescue and stabilize CFTR at the apical membrane may not be sufficient to restore its function unless the appropriate intracellular milieu is also reconstituted.

Chronic pulmonary pseudomonal infection in patients with cystic fibrosis: A model for early phase symbiotic evolution

Gain of "antimicrobial resistance" and "adaptive virulence" has been the dominant view of Pseudomonas aeruginosa (Pa) in cystic fibrosis (CF) in the progressively damaged host airway over the course of this chronic infection. However, the pathogenic effects of CF airway-adapted Pa strains are notably reduced. We propose that CF Pa and other bacterial cohabitants undergo host adaptation which resembles the changes found in bacterial symbionts in animal hosts. Development of clonally selected and intraspecific isogenic Pa strains which display divergent colony morphology, growth rate, auxotrophy, and antibiotic susceptibility in vitro suggests an adaptive sequence of infective exploitation-parasitism-symbiotic evolution driven by host defenses. Most importantly, the emergence of CF pseudomonal auxotrophy is frequently associated with a few specific amino acids. The selective retention or loss of specific amino acid biosynthesis in CF-adapted Pa reflects bacterium-host symbiosis and coevolution during chronic infection, not nutrient availability. This principle also argues against the long-standing concept of dietary availability leading to evolution of essential amino acid requirements in humans. A novel model of pseudomonal adaptation through multicellular bacterial syntrophy is proposed to explain early events in bacterial gene decay and decreased (not increased) virulence due to symbiotic response to host defense.

Pathophysiology of cystic fibrosis and drugs used in associated digestive tract diseases

Cystic fibrosis (CF) causes chronic infections in the respiratory tract and alters the digestive tract. This paper reviews the most important aspects of drug treatment and changes in the digestive tract of patients with CF. This is a review of the literature, emphasizing the discoveries made within the last 15 years by analyzing scientific papers published in journals indexed in the Scientific Electronic Library Online, Sciences Information, United States National Library of Medicine and Medical Literature Analysis and Retrieval System Online databases, both in English and Portuguese, using the key words: cystic fibrosis, medication, therapeutic, absorption, digestion. Randomized, observational, experimental, and epidemiological clinical studies were selected, among others, with statistical significance of 5%. This review evaluates the changes found in the digestive tract of CF patients including pancreatic insufficiency, constipation and liver diseases. Changes in nutritional status are also described. Clinical treatment, nutritional supplementation and drug management were classified in this review as essential to the quality of life of CF patients, and became available through public policies for monitoring and treating CF. The information gathered on CF and a multi professional approach to the disease is essential in the treatment of these patients.

[Therapeutic update in cystic fibrosis]

We present the recent therapeutic advances in the cystic fibrosis care. It concerns improvements in symptomatic treatment with the development of dry powder inhaled antibiotics that improved quality of life, and innovative treatments namely the modulators of the cystic fibrosis transmembrane protein conductance regulator (CFTR), molecules which act specifically at the level of the defective mechanisms implied in the disease. The life expectancy of cystic fibrosis patients born after 2000, is estimated now to be about 50 years. This improvement of survival was obtained with the organization of the care within the specialized centers for cystic fibrosis (Centre de ressource et de compétences de la mucoviscidose) and remains still based on heavy symptomatic treatments. Dry powder inhaled antibiotics constitute a significant time saving for patients to whom all the care can achieve two hours daily. Since 2012, the modulators of CFTR, molecules allowing a pharmacological approach targeted according to the type of the mutations, allows a more specific approach of the disease. Ivacaftor (Kalydeco(®)) which potentialises the function of the CFTR protein expressed on the cellular surface is now available for patients with the G551D mutation. Lumacaftor is going to be tested in association with ivacaftor in patients with the F508del mutation, that is present in at least 75% of the patients. The ataluren which allows the production of a functional protein CFTR in patients with a no sense mutation is the third representing of this new therapeutic class. We presently have numerous symptomatic treatments for the cystic fibrosis care. The development of CFTR modulators, today available to a restricted number of patients treated with ivacaftor represents a very promising therapeutic avenue. It will represent probably the first step to a personalized treatment according to CFTR genotype.

Nanotechnology approaches for inhalation treatment of fibrosis

Cystic fibrosis (CF) is an autosomal recessive monogenetic disease that afflicts nearly 70 000 patients worldwide. The mutation results in the accumulation of viscous mucus in multiple organs especially in the lungs, liver and pancreas. High associated morbidity and mortality is caused by CF due to the lack of effective therapies. It is widely accepted that morbidity and mortality caused by CF is primarily due to the respiratory manifestations of the disease. Consequently, several approaches were recently developed for treatment of lung complications of CF. However, the lack of effective methods for delivery and especially targeted delivery of therapeutics specifically to lung tissues and cells limits the efficiency of the therapy. Local pulmonary delivery of therapeutics has two major advantages over systemic application. First, it enhances the accumulation of therapeutics specifically in the lungs and therefore increases the efficiency of the treatment. Second, local lung delivery substantially prevents the penetration of the delivered drug into the systemic circulation limiting adverse side effects of the treatment on other organs and tissues. This review is focused on different approaches to the treatment of respiratory manifestations of CF as well as on methods of pulmonary delivery of therapeutics.

Modification of the salivary secretion assay in F508del mice--the murine equivalent of the human sweat test

BACKGROUND

In 2005 Best and Quinton established the salivary secretion assay in mice for the in vivo characterization of new drugs against cystic fibrosis (CF). However, limited data are available and the predictive value of this in vivo assay for treatment effects in CF patients is not fully understood.

METHODS

Therefore, we revisited the salivary secretion assay and systematically investigated the salivary secretion rates in different murine backgrounds and sexes, as well as in different CF mouse models. Moreover, we established quantification of salivary chloride content.

RESULTS

We found a strain- and sex-dependency of salivary secretion rates and were able to confirm the decreased β-adrenergic salivary secretion response in CFTR knockout mice (CFTR(tm1Unc)) as well as in the F508del CFTR mice of different origins (CFTR(tm1Kth) and CFTR(tm1Eur)). In heterozygous Cftr+/- and Cftr+/F508del mice, the isoprenaline-stimulated salivary secretion rate and the Cl(-) content were intermediate between values measured in WT and CF mice, indicating that this assay is also able to detect CF carriership. Pilocarpine-induced abnormalities in saliva chloride content in CF mice resembled the changes observed in the human sweat test.

CONCLUSIONS

Determination of murine salivary chloride content in combination with salivary secretion rate in CF mice may render the salivary secretion assay as a powerful tool for validation of new CF treatments.

Cost of cystic fibrosis: analysis of treatment costs in a specialized center in northern Italy

INTRODUCTION

Advances in cystic fibrosis (CF) therapy have resulted in improved survival and increasing treatment burden and costs. The economic impact of current treatment strategies for CF is poorly defined.

METHODS

The authors prospectively assessed direct medical costs (including hospitalizations, outpatient interventions, drugs, devices, dietetic products) in 165 consecutive CF patients (aged 5-39 years) seen between March and July 2009.

RESULTS

The mean annual cost/patient increased with age and lung disease severity from yy4,164 in children aged ≤5 years to yy30,123 in patients aged >5 years with severe lung disease (forced expiratory volume in 1 second [FEV1] <40% of predicted). The increase in costs involved all items, with a progressive increase in cost attributed to hospitalizations.

CONCLUSION

Treatment of CF is associated with relevant cost for the Italian National Healthcare Service. Costs of illness tend to increase progressively with age, suggesting that increasing economic resources should be allocated to the treatment of CF, given the increasing number of patients surviving into adulthood.