Neutrophil Elastase Enhances Sputum Solubilization in Cystic Fibrosis Patients Receiving DNase Therapy

Cystic fibrosis patients suffer from chronic lung infection and inflammation due to the secretion of viscous sputum. Sputum viscosity is caused by extracellular DNA, some of which originates from the release of neutrophil extracellular traps (NETs). During NET formation neutrophil elastase (NE) partially processes histones to decondense chromatin. NE is abundant in CF sputum and is thought to contribute to tissue damage. Exogenous nucleases are a palliative treatment in CF as they promote sputum solubilization. We show that in a process reminiscent of NET formation, NE enhances sputum solubilization by cleaving histones to enhance the access of exogenous nucleases to DNA. In addition, we find that in Cf sputum NE is predominantly bound to DNA, which is known to downregulate its proteolytic activity and may restrict host tissue damage. The beneficial role of NE in CF sputum solubilization may have important implications for the development of CF therapies targeting NE

Dysfunction of Nrf-2 in CF Epithelia Leads to Excess Intracellular H2O2 and Inflammatory Cytokine Production

Cystic fibrosis is characterized by recurring pulmonary exacerbations that lead to the deterioration of lung function and eventual lung failure. Excessive inflammatory responses by airway epithelia have been linked to the overproduction of the inflammatory cytokine IL-6 and IL-8. The mechanism by which this occurs is not fully understood, but normal IL-1β mediated activation of the production of these cytokines occurs via H2O2 dependent signaling. Therefore, we speculated that CFTR dysfunction causes alterations in the regulation of steady state H2O2. We found significantly elevated levels of H2O2 in three cultured epithelial cell models of CF, one primary and two immortalized. Increases in H2O2 heavily contributed to the excessive IL-6 and IL-8 production in CF epithelia. Proteomic analysis of three in vitro and two in vivo models revealed a decrease in antioxidant proteins that regulate H2O2 processing, by ≥2 fold in CF vs. matched normal controls. When cells are stimulated, differential expression in CF versus normal is enhanced; corresponding to an increase in H2O2 mediated production of IL-6 and IL-8. The cause of this redox imbalance is a decrease by ∼70% in CF cells versus normal in the expression and activity of the transcription factor Nrf-2. Inhibition of CFTR function in normal cells produced this phenotype, while N-acetyl cysteine, selenium, an activator of Nrf-2, and the overexpression of Nrf-2 all normalized H2O2 processing and decreased IL-6 and IL-8 to normal levels, in CF cells. We conclude that a paradoxical decrease in Nrf-2 driven antioxidant responses in CF epithelia results in an increase in steady state H2O2, which in turn contributes to the overproduction of the pro-inflammatory cytokines IL-6 and IL-8. Treatment with antioxidants can ameliorate exaggerated cytokine production without affecting normal responses

Effect of ivacaftor treatment in patients with cystic fibrosis and the G551D-CFTR mutation: patient-reported outcomes in the STRIVE randomized, controlled trial

BACKGROUND: Cystic fibrosis (CF) is an inherited, rare autosomal recessive disease that results in chronically debilitating morbidities and high premature mortality. We evaluated how ivacaftor treatment affected CF symptoms, functioning, and well-being, as measured by the Cystic Fibrosis Questionnaire-Revised (CFQ-R), a widely-used patient-reported outcome (PRO) measure. METHODS: STRIVE, a double-blind, placebo-controlled randomized trial, evaluated ivacaftor (150 mg) in CF patients aged 12+ with the G551D-CFTR mutation for 48 weeks. Treatment effect analysis used a mixed-effects repeated measures model. Treatment benefit analyses applied the cumulative distribution function and a categorical analysis of change scores (“improvement,” “no change,” or “decline”). Content-based interpretation examined treatment effect on specific item responses. RESULTS: Data from 152 patients with a baseline CFQ-R assessment were analyzed. The treatment effect analysis favored treatment with ivacaftor over placebo on the Body Image, Eating, Health Perceptions, Physical Functioning, Respiratory, Social Functioning, Treatment Burden, and Vitality scales. Findings were supported by the analysis of categorical change. On all CFQ-R scales, the percentage of patients who improved was greater for ivacaftor. In the content-based analysis, the treatment benefit was characterized by better scores across a broad range of domains. CONCLUSIONS: Results illustrate broad benefits of ivacaftor treatment across many domains: respiratory symptoms, physical and social functioning, health perceptions, and vitality, as measured by the CFQ-R. The breadth of improvements reflects the systemic mechanism of action of ivacaftor compared to other therapies. Findings support the patient-reported value of ivacaftor treatment in this patient population. TRIAL REGISTRATION: ClinicalTrials.gov NCT00909532 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12955-015-0293-6) contains supplementary material, which is available to authorized users

Open label study of inhaled aztreonam for Pseudomonas eradication in children with cystic fibrosis: The ALPINE study

AbstractBackgroundConsensus guidelines recommend early treatment to eradicate newly acquired Pseudomonas aeruginosa (Pa) infection in cystic fibrosis (CF) patients although there is no single preferred regimen. Aztreonam for inhalation solution (AZLI) significantly reduces sputum Pa density in CF patients with chronic Pa infection and has been well tolerated in the pediatric population. This single-arm, open-label Aztreonam Lysine for Pseudomonas Infection Eradication (ALPINE) study was conducted to evaluate the safety and efficacy of a 28-day treatment course of AZLI to eradicate newly acquired Pa infection in pediatric CF patients.MethodsCF patients (3months to <18years) with new onset Pa infection were treated with AZLI 75mg 3 times daily for 28days. New onset Pa infection was defined as first lifetime Pa-positive respiratory tract culture (throat swab, sputum) or Pa-positive culture after a ≥2-year history of Pa-negative cultures (≥2cultures/year). Sputum or throat swab cultures were collected at study entry (baseline) and at weeks 4 (end of treatment), 8, 16, and 28. Primary endpoint was the percentage of patients with cultures negative for Pa at all post-treatment time points.ResultsA total of 105 pediatric CF patients enrolled (3months to <2years, n=24; 2 to <6years, n=25; 6 to <18years, n=56). Of the 101 patients who completed treatment, 89.1% (n=90) were free of Pa at the end of treatment and 75.2% (n=76) were free of Pa 4weeks after the end of treatment. Of the 79 patients evaluable for the primary endpoint, 58.2% were free of Pa at all post-treatment time points.ConclusionsAZLI was effective and well tolerated in eradicating Pa from newly infected pediatric patients with CF. These eradication rates are consistent with success rates reported in the literature for various antibiotic regimens, including other inhaled antibiotics studied for eradication.ClinicalTrials.gov: NCT01375049

A pilot trial on safety and efficacy of erythrocyte-mediated steroid treatment in CF patients

<p>Abstract</p> <p>Background</p> <p>Chronic neutrophil inflammation of the respiratory tract tissues plays a key role in the pathogenesis and in prognosis of cystic fibrosis (CF). It is evident that an anti-inflammatory therapy represents an important step in the treatment of CF patients. Corticosteroids and ibuprofen have been proven to slow down the impairment of the pulmonary function in CF patients but their use is limited by the frequency of adverse events. A novel strategy for delivering low doses of steroids for long periods through the infusion of autologous erythrocytes loaded with dexamethasone has been recently set up. A recent study suggested the feasibility of therapy with low doses of corticosteroids delivered through engineered erythrocytes in CF patients. This study presents a further analysis of safety and efficacy of this therapy.</p> <p>Methods</p> <p>The treatment group was not randomised and the assignment was based on the patient's consent. Patients entered the study if they had a forced expiratory volume in 1 second (FEV1) <70%, puberty development completed, pancreatic insufficiency, and chronic pulmonary infection requiring frequent cycles of intravenous antibiotic therapy. Patients were excluded if they underwent systemic corticosteriod therapy in the three months preceding the experimental treatment or were on therapy with non-steroidal anti inflammatory drugs (NASDs), or if they had liver CF disease, allergic bronchopulmonary aspergillosis, or positive tuberculin test. Controls were patients who followed a standard treatment, who fulfilled the enrolment criteria, and who were matched to the experimental group by gender, age, and severity of the disease.</p> <p>Results</p> <p>Nine patients in the experimental group received the treatment once a month for a period of 24 month. Patients did not develop diabetes, cataract, or hypertension, or other typical side effects of steroid treatment during the follow up period. There was a constant improvement of FEV1 in patients undergoing the experimental treatment compared to a gradual decrease of the same parameter in the standard therapy group (P = 0.04). The average of clinic and radiological indexes did not vary. The number of infective relapses that have required antibiotic intravenous therapy was not different in the two groups, although the average of these episodes was slightly higher in the experimental therapy group.</p> <p>Conclusion</p> <p>Intraerythrocyte corticosteroid treatment may stabilize the respiratory function in CF patients but is often considered too invasive by patients. The results obtained by our study may help planning an experimental, controlled, randomised study. A sample size of 150 patients per group would be sufficient for demonstrating such a difference with a 95% confidence interval and a power of 90%.</p