A multicenter study of alternate-day prednisone therapy in patients with cystic fibrosis. Cystic Fibrosis Foundation Prednisone Trial Group

Pathophysiology and management of pulmonary infections in cystic fibrosis

This comprehensive State of the Art review summarizes the current published knowledge base regarding the pathophysiology and microbiology of pulmonary disease in cystic fibrosis (CF). The molecular basis of CF lung disease including the impact of defective cystic fibrosis transmembrane regulator (CFTR) protein function on airway physiology, mucociliary clearance, and establishment of Pseudomonas aeruginosa infection is described. An extensive review of the microbiology of CF lung disease with particular reference to infection with P. aeruginosa is provided. Other pathogens commonly associated with CF lung disease including Staphylococcal aureus, Burkholderia cepacia, Stenotrophomonas maltophilia, Achromobacter xylosoxidans and atypical mycobacteria are also described. Clinical presentation and assessment of CF lung disease including diagnostic microbiology and other measures of pulmonary health are reviewed. Current recommendations for management of CF lung disease are provided. An extensive review of antipseudomonal therapies in the settings of treatment for early P. aeruginosa infection, maintenance for patients with chronic P. aeruginosa infection, and treatment of exacerbation in pulmonary symptoms, as well as antibiotic therapies for other CF respiratory pathogens, are included. In addition, the article discusses infection control policies, therapies to optimize airway clearance and reduce inflammation, and potential future therapies.

Stratégies anti-inflammatoires dans la mucoviscidose

Cystic fibrosis lung inflammation is early, sustained and severe and would justify an anti-inflammatory treatment. At present, the inhaled corticosteroid treatment did not give evidence of efficacy, contrary to the oral presentation, but at the cost of side effects. Azithromycin gives more encouraging results with a good tolerance. New molecules are in the process of validation.

Low-dose methotrexate for advanced pulmonary disease in patients with cystic fibrosis

Inflammation is a hallmark in the pathogenesis of pulmonary destruction in cystic fibrosis (CF). There is no proven effective systemic anti-inflammatory treatment for CF patients with advanced pulmonary disease. Methotrexate (MTX) is known as an effective anti-inflammatory treatment in asthma and in juvenile rheumatoid arthritis. The question was: Is an improvement in pulmonary function achievable with low-dose MTX in patients with cystic fibrosis and advanced pulmonary disease.?

METHODS

We treated five CF patients with advanced pulmonary disease, who deteriorated in spite of intensive conventional therapy on an individual basis with low-dose MTX. FEV1% and immunoglobulin G (IgG) serum levels were followed from the year before to the year after starting with MTX.

RESULTS

In the year before starting with MTX, FEV1% decreased (median: 10% FEV1; range 9-15% FEV1; P<0.005) after starting with MTX, FEV1% increased (median: 9% FEV1; range: 2-15% FEV1; P<0.05). IgG changed (median: -2 g/l; range: 0.2 to -7.3 g/l) in the first year with MTX.

CONCLUSION

These preliminary data suggest a beneficial effect of MTX even in advanced pulmonary disease in CF patients and supports the need for a controlled prospective study.

Quality of life in children and adolescents with cystic fibrosis: implications for optimizing treatments and clinical trial design

Health related quality of life (QOL) as an outcome measure in clinical trials is becoming increasingly important. Trials should not only be able to demonstrate the pharmacologic activity of a therapy, but of equal importance, they should demonstrate clinical effectiveness that is of significant benefit to the patient. QOL measurement provides a way of incorporating the child/parent's perspective of how cystic fibrosis (CF) and its therapies impact on their lives. Several validated generic instruments have been employed to measure QOL in adolescents and adults. QOL assessment is more difficult in children and, therefore, has been employed less often in children with CF. Difficulties arise with the issue of whether children can report their own experiences directly, or whether a parent or clinician should report on behalf of the child. A child-centered approach is imperative since the literature indicates that children are able to report on their own QOL. An additional complication has been the use of adult measures with children. These are often inappropriate in their complexity, use of language, response scales, and time frame. The evaluation of pharmacologic therapies can profit from QOL measurement. The effectiveness of a drug and any adverse effects that impact on daily life can be assessed from the child/parent's viewpoint. Home therapy versus hospital therapy and drug delivery systems, are additional areas where QOL as an outcome measure is valuable. There have been relatively few appropriately powered trials in CF, and only a minority of these have evaluated QOL as an outcome measure. This review highlights areas where QOL measurement is appropriate. It focuses on the pharmacologic trials that have employed QOL assessment for antibiotic, mucociliary clearance, anti-inflammatory, and nutritional therapies. Methodological issues of incorporating QOL assessment into trials center on cross-cultural and data interpretation issues. QOL measurement in CF has been patchy and largely unreliable. The notion that improved symptoms equate with improved QOL is erroneous. Measurement of how symptoms impact on QOL is essential. Currently, the development and validation of CF specific measures (across the CF age range) provides optimism for appropriate QOL measurement in clinical trials, and for future meta-analysis and systematic reviews.

Cystic fibrosis

Cystic fibrosis is the most common autosomal recessive disorder in white people, with a frequency of about 1 in 2500 livebirths. Discovery of the mutated gene encoding a defective chloride channel in epithelial cells--named cystic fibrosis transmembrane conductance regulator (CFTR)--has improved our understanding of the disorder's pathophysiology and has aided diagnosis, but has shown the disease's complexity. Gene replacement therapy is still far from being used in patients with cystic fibrosis, mostly because of difficulties of targeting the appropriate cells. Life expectancy of patients with the disorder has been greatly increased over past decades because of better notions of symptomatic treatment strategies. Here, we summarise advances in understanding and treatment of cystic fibrosis, focusing on pulmonary disease, which accounts for most morbidity and deaths.

[Complementary therapies in cystic fibrosis: evidence of therapeutic benefits and treatment recommendations]

Cystic fibrosis (CF) is an autosomal-recessive disorder that predominantly affects the respiratory system. When this disease was described in 1938 the mortality rate was approximately 70 % in the first year of life. Survival has dramatically increased from a median of approximately 4 years in the 1960s to 19 years in the 1970s and 33 years in 2001 according to figures from the American Cystic Fibrosis Foundation. This impressive increase in the life expectancy of individuals with CF is undoubtedly related to recent advances in the organization of specialized CF units and to the use of new therapies against respiratory involvement.The traditional basis of treatment for CF lung disease includes nutritional support, antibiotic therapy, chest physical therapy and aerobic exercise. Preventive measures such as influenza vaccination and avoidance of tobacco smoke are also useful. Several new approaches such as ion transport therapy, protein therapy and gene therapy are currently being developed. Many studies have provided clear evidence of the therapeutic benefits of antibiotics, respiratory physiotherapy, exercise, and nutrition. In this article we review the scientific evidence on the advantages of the use of several therapeutic interventions against inflammation, increased sputum viscoelasticity and adhesiveness, and bronchial obstruction in CF patients.

Factors influencing outcomes in cystic fibrosis: a center-based analysis

CONTEXT

Guidelines for managing cystic fibrosis (CF) patients have been widely circulated, but little is known about the variations in practice between sites and their association with outcomes.

OBJECTIVE

To determine whether differences in lung health existed between groups of patients attending different CF care sites and to determine whether these differences are associated with differences in monitoring and intervention.

DESIGN

The analysis was conducted using data from the Epidemiologic Study of Cystic Fibrosis from 1995 through 1996.

SETTING

This was an observational database collecting prospective information from a large number of CF patients undergoing routine care in North America.

PARTICIPANTS

Participating sites that had at least 50 CF patients who had each made at least one visit to a center during the 2-year study period were ranked on the basis of median values for FEV(1) within each of three age groups (6 to 12 years, 13 to 17 years, and >or= 18 years).

INTERVENTIONS

There were no prespecified interventions in this observational study.

MAIN OUTCOME MEASURES

The frequency of patient monitoring and the use of therapeutic interventions were compared between sites in the upper and lower quartiles after stratification within the site for disease severity.

RESULTS

Within-site rankings tended to be consistent across the three age groups. Patients who were treated at higher ranking sites had more frequent monitoring of their clinical status, measurements of lung function, and cultures for respiratory pathogens. These patients also received more interventions, particularly IV antibiotics for pulmonary exacerbations.

CONCLUSION

We found substantial differences in lung health across different CF care sites. We found that frequent monitoring and increased use of appropriate medications in the management of CF are associated with improved outcomes.

Pharmacological approaches for the discovery and development of new anti-inflammatory agents for the treatment of cystic fibrosis

Some of the most important pathobiology in cystic fibrosis occurs not as a direct result of impaired chloride transport, but the downstream consequences of defective CFTR function, particularly the lung infection and inflammation that ultimately takes the lives of most patients. Interrupting the vicious cycle of infection and inflammation is effective in slowing the course of the disease, and antibiotics have long been the staple of pulmonary therapy. However, limiting the inflammatory response in the CF lung is also effective. High dose ibuprofen clearly retards progression of lung disease, but also entrains adverse events that mar its therapeutic utility, so alternative anti-inflammatory agents are necessary. Because of the remarkable therapeutic success of ibuprofen, consideration should be given to finding less toxic alternatives. However, it is also appropriate to consider the mechanisms by which the inflammatory response occurs in the CF lung, and identify sites to interrupt it. Sites at which therapeutic intervention is possible are the neutralization of cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, or IL-8 with specific antibodies or receptor antagonists, inhibition of the intracellular signaling cascades that result in cytokine production (for example, at the level of p38 MAP kinase), application of cytokines such as Il-10 that are themselves anti-inflammatory, or modulating the arachidonic acid cascade with inhibitors directed at leukotriene B(4). In addition, interventions designed to limit the consequences of the inflammatory response, such as protease inhibitors and reagents to limit the ill effects of DNA accumulation in airways, are in use. To limit adverse effect and concentrate the therapeutic effect, there may be value in targeting delivery of the therapeutic reagents to the inflamed site, either by specifically directing systemic delivery or by exploitation of the aerosol route. Treating the inflammatory response is important, for the data from the ibuprofen study show that the effects of anti-inflammatory therapy are additive or even synergistic with intensive conventional therapy and alter the rate of decline of pulmonary function, and therefore benefits for survival of patients with CF are to be expected.

Understanding bacterial biofilms in patients with cystic fibrosis: current and innovative approaches to potential therapies

Chronic P. aeruginosa infection is characterized by production of mucoid alginate and formation of microcolonies (biofilm) as seen in the lungs of cystic fibrosis patients. Oxygen radicals produced by the inflammatory response polymorphonuclear leucocytes induces the alginate production. The biofilm mode of growth is the survival strategy of environmental bacteria and alginate biofilms are also protected against antibiotics and against the immune response in the lungs of the patient. Quorum sensing is important for early and mature biofilm formation and also for the severity of the infection. The new knowledge of the mechanisms involved in biofilm formation opens up new possibilities for therapeutic intervention strategies involving e.g. inhibitors of quorum sensing.

Potential role of macrolide antibiotics in the management of cystic fibrosis lung disease

Current management of cystic fibrosis (CF) lung disease includes the use of antibiotics, nutritional support, and airway clearance therapies. However, despite recent advances in pharmacologic therapies including DNase and aerosolized tobramycin, deterioration in lung function persists. Recent investigations have shed new light on the pathogenic mechanisms by which establishes itself within the airways of patients with CF and contributes to the progressive decline in lung function. In particular, the presence of biofilms and other virulence mechanisms allow evasion of local host defenses and establishment of a chronic localized inflammatory response resulting in lung damage. Macrolide antibiotics appear to have a promising role in the management of CF lung disease even though they do not exhibit intrinsic antipseudomonal activity. Recent evidence demonstrates that they can disrupt quorum sensing, a cell-to-cell signaling process linked to the formation of biofilms. In addition, they inhibit NF-kappab and AP-1, nuclear factors that control the expression of proinflammatory cytokines. Their ability to decrease sputum viscosity and increase sputum clearance may complement existing airway clearance therapies. Preliminary clinical trials have shown modest improvement in pulmonary function.

Inflammatory response in airway epithelial cells isolated from patients with cystic fibrosis

The concept that inflammatory gene expression is dysregulated in airway epithelial cells from patients with cystic fibrosis (CF) is controversial. To examine this possibility systematically, responses to inflammatory stimuli were compared in CF airway epithelial cell lines without versus with wild-type CF transmembrane conductance regulator (CFTR) complementation and in tracheobronchial epithelial cells from patients with versus without CF. Epithelial cell expression of the leukocyte adhesion glycoprotein intercellular adhesion molecule-1 (ICAM-1) and release of the neutrophil chemoattractant interleukin (IL)-8 were determined under basal conditions or after exposure to stimuli important in CF airway inflammatory responses. We found that uncorrected CF airway epithelial cell lines inconsistently expressed higher ICAM-1 and IL-8 levels. Human CF tracheobronchial epithelial cells in primary culture released moderately increased IL-8 only after exposure to Pseudomonas aeruginosa. In CF cells with higher IL-8 release, transient expression of wild-type CFTR using an adenoviral vector did not specifically affect cytokine levels. The results indicate that there is considerable variability in airway epithelial cell responses to inflammatory stimuli among different individuals and cell models systems. Although increased ICAM-1 and IL-8 expression are observed in some CF airway epithelial cell models, many CF cells do not exhibit significant dysregulation of these important inflammatory genes.

Evidence-based medicine in cystic fibrosis: how should practice change?

This critical review of current practice and research in some aspects of cystic fibrosis (CF) concludes that, despite recent success in prolonging life expectancy, there is still room for improvement in terms of earlier diagnosis and earlier intervention in some of its complications. Specifically, the body of evidence implies that neonatal diagnosis; early attention to nutrition, staphylococcal and pseudomonal infection, and diabetes mellitus; and early treatment with dornase alfa can all be expected to improve patients' quality and quantity of life.

Itraconazole treatment of allergic bronchopulmonary aspergillosis in patients with cystic fibrosis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients is a potentially fatal inflammatory disease due to the dual-type immune response provoked by the fungal antigens. Despite serious side effects long-term treatment with corticosteroids is often required. Itraconazole has been reported to be a useful steroid-sparing agent.

METHODS

In a retrospective follow-up of 21 CF patients from a total of 250 treated once or twice within a five-year study period (1994-98), 9 patients were treated with systemic glucocorticosteroids in combination with itraconazole and 12 patients were treated with itraconazole (200-600 mg/day) as monotherapy.

RESULTS

During treatment the percentage of Aspergillus fumigatus (AF)-positive sputum cultures significantly reduced (P < 0.05); precipitating antibodies to AF decreased significantly in all patients (P < 0.05); forced expiratory volume (FEV1) increased to pre-exacerbation level; total IgE levels decreased in 42% of patients on monotherapy and in 56% on combination therapy. Specific IgE (radioallergosorbant; RAST) level decreased in 6 of 21 patients. Eleven patients had transient increased levels of alanine transaminase (ALAT). One patient had isolated increase in alkaline phosphatase and another in aspartate transaminase (ASAT).

CONCLUSIONS

High dose itraconazole as monotherapy or in combination with systemic glucocorticosteroids seems effective in CF patients with ABPA. No hepatotoxicity was observed during long-term therapy.

"CF asthma": what is it and what do we do about it?

The diagnosis of "CF asthma" is problematic and it is difficult to determine which patients have a combination of CF and asthma and which have asthma like symptoms caused by inflammation of the CF lung. This may not matter, however; the relevance lies in the possible approaches to treatment.

Amphotericin B-induced hepatorenal failure in cystic fibrosis

Although nephrotoxicity is a common and well-recognized side effect of amphotericin B, hepatotoxicity is rare. We report on a 9-year-old girl with cystic fibrosis who developed fulminant renal and hepatic dysfunction following a short course of intravenous amphotericin B for a suspected aspergillus infection, although she did not have clinical evidence of invasive aspergillosis. The toxicity became apparent after changing to liposomal amphotericin. This association of renal and hepatotoxicity with liposomal amphotericin B has not previously been reported in children.

Intracutaneous tests with recombinant allergens in cystic fibrosis patients with allergic bronchopulmonary aspergillosis and Aspergillus allergy

Allergic bronchopulmonary aspergillosis (ABPA), an intensive inflammatory reaction to Aspergillus fumigatus, can cause irreversible lung damage in patients with cystic fibrosis (CF). The aim of this study was to assess if intracutaneous testing with recombinant A. fumigatus allergens (rAsp f ) allowed a reliable diagnosis of ABPA. Fifty patients with CF were tested, 12 suffering from ABPA, 21 with allergy to A. fumigatus, and 17 CF control patients not sensitized to A. fumigatus. All patients with ABPA reacted to at least one of the two intracellular A. fumigatus allergens rAsp f 4, a 30-kD protein of unknown biologic function, and rAsp f 6, a 23-kD manganese superoxide dismutase, at a concentration of 10(-2) microg/ml. The intracutaneous tests were negative or only marginally positive in the patients with allergy to A. fumigatus and completely negative in the CF control patients. The differential responses to the recombinant A. fumigatus allergens were in perfect agreement with our previous serologic results, so that rAsp f 4 and rAsp f 6 can be considered specific markers for ABPA. Early diagnosis of the disease might help to prevent irreversible lung damage and minimize possible steroid-mediated side effects as a consequence of an optimized control of the disease.

Effects of megestrol acetate on weight gain, body composition, and pulmonary function in patients with cystic fibrosis

OBJECTIVES

Malnutrition is a negative prognostic indicator in patients with cystic fibrosis (CF) and may accentuate pulmonary decline. We tested whether megestrol acetate would have beneficial effects on growth in patients with CF and pancreatic insufficiency.

STUDY DESIGN

We performed a randomized, double-blind, placebo controlled study. All patients were taking replacement enzymes to compensate for pancreatic insufficiency. Patients (n = 17) were randomly assigned to receive either megestrol acetate or placebo.

RESULTS

The treatment group had a significant increase in weight-for-age z scores compared with placebo and reached 100% of their ideal body weight within 3 months of initiating therapy. Weight gain included both fat and fat-free mass. Improved pulmonary function (forced vital capacity and forced expiratory volume in 1 second) was noted in the treatment group compared with placebo (P <.04). Reversible adrenal suppression was observed in the majority of patients who received megestrol acetate.

CONCLUSIONS

Short-term use of megestrol acetate results in significant weight gain and improved pulmonary function in malnourished subjects with CF. Our study provides a controlled basis for this intervention, identifies important side effects, and provides the foundation for multiyear, longitudinal trials in a larger number of patients with CF.

Lung infections associated with cystic fibrosis

While originally characterized as a collection of related syndromes, cystic fibrosis (CF) is now recognized as a single disease whose diverse symptoms stem from the wide tissue distribution of the gene product that is defective in CF, the ion channel and regulator, cystic fibrosis transmembrane conductance regulator (CFTR). Defective CFTR protein impacts the function of the pancreas and alters the consistency of mucosal secretions. The latter of these effects probably plays an important role in the defective resistance of CF patients to many pathogens. As the modalities of CF research have changed over the decades from empirical histological studies to include biophysical measurements of CFTR function, the clinical management of this disease has similarly evolved to effectively address the ever-changing spectrum of CF-related infectious diseases. These factors have led to the successful management of many CF-related infections with the notable exception of chronic lung infection with the gram-negative bacterium Pseudomonas aeruginosa. The virulence of P. aeruginosa stems from multiple bacterial attributes, including antibiotic resistance, the ability to utilize quorum-sensing signals to form biofilms, the destructive potential of a multitude of its microbial toxins, and the ability to acquire a mucoid phenotype, which renders this microbe resistant to both the innate and acquired immunologic defenses of the host.

New and emerging therapies for pulmonary complications of cystic fibrosis

In the decade since the gene for cystic fibrosis (CF) was discovered, research into potential therapeutic interventions has progressed on a number of different fronts. The vast majority of morbidity and mortality in CF results from inflammation and infection of the airways. Direct delivery of antibacterials to the airway secretions via a nebuliser is an attractive therapeutic option, and a novel formulation of tobramycin designed for such a purpose has been demonstrated to improve spirometry and decrease the need for intravenous antibacterials. In addition, early clinical trials are studying the effects of small peptides with antibiotic properties (defensins) delivered directly to the airways. Inflammation, whether secondary to infection or an independent feature of CF, leads to progressive bronchiectasis. Anti-inflammatories such as prednisone and possibly ibuprofen have been shown to decrease the rate of respiratory decline in patients with CF but have tolerability profiles that limit clinical usefulness. Macrolides also have anti-inflammatory properties and clinical trials are now ongoing to assess the efficacy of these agents in CF. Multiple agents, including uridine triphosphate (UTP), genistein, phenylbutyrate and CPX (cyclopentyl dipropylxanthine), have been demonstrated in cell culture to at least partially correct the primary defect of ion transport related to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). No agent of this class has yet demonstrated clinical effectiveness, but several are in preclinical and early clinical trials. Finally, gene therapy that allows for the incorporation and expression of wild-type CFTR in respiratory epithelial cells would be definitive therapy for CF. However, multiple barriers to delivery and expression need to be overcome. With research proceeding on these multiple fronts, new therapies for pulmonary complications promise to continue to increase the life expectancy of individuals with CF.

A(2) adenosine receptors regulate CFTR through PKA and PLA(2)

We investigated adenosine (Ado) activation of the cystic fibrosis transmembrane conductance regulator (CFTR) in vitro and in vivo. A(2B) Ado receptors were identified in Calu-3, IB-3-1, COS-7, and primary human airway cells. Ado elevated cAMP in Calu-3, IB-3-1, and COS-7 cells and activated protein kinase A-dependent halide efflux in Calu-3 cells. Ado promoted arachidonic acid release from Calu-3 cells, and phospholipase A(2) (PLA(2)) inhibition blocked Ado-activated halide efflux in Calu-3 and COS-7 cells expressing CFTR. Forskolin- and beta(2)-adrenergic receptor-stimulated efflux were not affected by the same treatment. Cytoplasmic PLA(2) (cPLA(2)) was identified in Calu-3, IB-3-1, and COS-7 cells, but cPLA(2) inhibition did not affect Ado-stimulated cAMP concentrations. In cftr(+) and cftr(-/-) mice, Ado stimulated nasal Cl(-) secretion that was CFTR dependent and sensitive to A(2) receptor and PLA(2) blockade. In COS-7 cells transiently expressing DeltaF508 CFTR, Ado activated halide efflux. Ado also activated G551D CFTR-dependent halide efflux when combined with arachidonic acid and phosphodiesterase inhibition. In conclusion, PLA(2) and protein kinase A both contribute to A(2) receptor activation of CFTR, and components of this signaling pathway can augment wild-type and mutant CFTR activity.

Towards the pharmacogenomics of cystic fibrosis

Cystic fibrosis (CF) is the most common lethal recessive genetic disease affecting children in Europe and the US. CF is a multiorgan disease and may present a variety of clinical symptoms, like chronic obstructive lung disease, exocrine pancreatic insufficiency (PI) and elevated sweat chloride concentration. CF mutations have also been found in other related clinical diseases such as congenital bilateral absence of the vas deferens (CBAVD), disseminated bronchiectasis and chronic pancreatitis. These clinical overlaps pose etiopathogenetic, diagnostic and therapeutic questions. Despite stunning advances in genomic technologies and drug discovery, drug therapy often improves disease symptoms but does not cure the disease. One of the main causes of this failure in CF cure may be attributable to genetic variability and to the scarce knowledge of CF biochemistry. Therefore, knowing the genotype of a patient might help improve drug efficacy, reduce toxicity and suggests innovative genomic-based therapy approaches.

Inflammation and cystic fibrosis pulmonary disease

Inflammation plays a primary role in the pathogenesis of cystic fibrosis (CF)-related lung disease. Controlling the inflammatory process with antiinflammatory therapy may slow the progression of pulmonary disease and thereby decrease morbidity. Despite potential benefits of antiinflammatory therapy, both the decision to treat and selection of the most appropriate therapeutic agent are controversial. Although oral corticosteroids are associated with reduced progression of pulmonary disease, the risk of clinically significant adverse effects limits long-term therapy. Clinical studies with inhaled corticosteroids failed to report positive effects on reducing airway inflammation. Based on available clinical data, routine therapy with these agents should be limited to patients with asthma or steroid-responsive wheezing. High-dosage ibuprofen has a beneficial effect on reducing the annual rate of decline in pulmonary function in patients with mild lung disease. Whereas initial results are encouraging, they do not support routine ibuprofen therapy in all patients with CE However, as advocated by the Cystic Fibrosis Foundation, high-dosage ibuprofen may be considered in children 5-12 years of age with a baseline forced expiratory volume of 60% predicted or greater.

Administration of aerosolized antibiotics in cystic fibrosis patients

High rates of colonization and the challenge of managing Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) have necessitated a search for safe and effective antibiotics. Currently, therapy with an aminoglycoside in combination with a beta-lactam or a quinolone antibiotic is the standard. Unfortunately, it is difficult to deliver high doses of these antibiotics via the IV route without significant systemic adverse events (AEs) (eg, ototoxicity and nephrotoxicity). Recently, a reformulation of the aminoglycoside antibiotic tobramycin has become available in a preservative-free, pH-adjusted solution for inhalation by jet nebulizer. A 96-week series of clinical studies including 520 patients, aged > or = 6 years, with moderate-to-severe CF has evaluated the long-term safety and effectiveness of this formulation. Patients received tobramycin solution for inhalation (TSI) or placebo, which was administered in alternating cycles of 28-days-on and 28-days-off therapy, plus their usual CF care for 6 months with open-label follow-up extended to 2 years. Most AEs declined in frequency with increasing TSI exposure. Patients receiving TSI spent 25 to 33% fewer days in the hospital. Following the initiation of TSI treatment, patients experienced significant increases in FEV(1). FEV(1) values were maintained above baseline for the duration of the study series. Antibiotic susceptibility of the bacterial isolates did not predict clinical response. TSI was safe, well-tolerated, and effective for long-term treatment (96 weeks) of P aeruginosa colonization and infection in CF patients.

Antibacterial activity of apical surface fluid from the human airway cell line Calu-3: pharmacologic alteration by corticosteroids and beta(2)-agonists

Calu-3 cells, a human lung carcinoma cell line with properties like serous cells of the upper airway, were used to develop an in vitro model for airway antibacterial activity. Calu-3 cell monolayers were cultured on permeable supports at an air-liquid interface. Apical surface fluid (ASF) was collected by washing; antibacterial activity was assayed by incubating ASF washings with bacteria for 18 h and counting surviving colony-forming units. ASF washings killed Escherichia coli and Pseudomonas aeruginosa. Antibacterial activity was salt sensitive and dependent on protein concentration. After washing, approximately 30 h were required before antibacterial activity recovered to its initial level. After culturing with topical corticosteroids (budesonide, triamcinolone, or beclomethasone, 0.1 microg/ml for 48 h), ASF antibacterial activity was 4- to 10-fold greater than the ASF from control monolayers. The increase in antibacterial activity was dose-dependent. The beta(2)-agonists salbutamol and terbutaline (100 microg/ml for 48 h) decreased ASF antibacterial activity by 5- to 8-fold. The nonsteroidal anti-inflammatory agents ibuprofen and cromolyn sodium had no effect. Our results are most consistent with agonist-dependent changes in the composition of ASF antibacterial proteins. We conclude that Calu-3 cells synthesize and secrete antibacterial proteins and that clinical agents can alter these functions.

Proinflammatory cytokine responses to P. aeruginosa infection in human airway epithelial cell lines

A tendency toward excessive inflammation in cystic fibrosis (CF) patients often accompanies lung infections with Pseudomonas aeruginosa. We tested the cytokine response to P. aeruginosa in two pairs of human airway epithelial cell lines matched except for CF transmembrane conductance regulator activity. The 9/HTEo(-) CF-phenotypic cell line produced significantly more interleukin (IL)-8, IL-6, and granulocyte-macrophage colony-stimulating factor but not regulated on activation normal T cell expressed and secreted (RANTES) in response to Pseudomonas than the 9/HTEo(-) control line, and the differences widened over time. Similarly, a 16HBE cell line lacking transmembrane conductance regulator activity showed enhanced IL-8 and IL-6 responses compared with the control cell line. The pharmacology of the cytokine response also differed because dexamethasone reduced cytokine production to similar levels in the matched cell lines. The protracted proinflammatory cytokine response of the CF-phenotypic cell lines suggests that the limiting mechanisms of normal cells are absent or attenuated. These results are consistent with in vivo observations in patients with CF and suggest that our novel cell lines may be useful for further investigation of the proinflammatory responses in CF airways.

Predictive 5-year survivorship model of cystic fibrosis

The objective of this study was to create a 5-year survivorship model to identify key clinical features of cystic fibrosis. Such a model could help researchers and clinicians to evaluate therapies, improve the design of prospective studies, monitor practice patterns, counsel individual patients, and determine the best candidates for lung transplantation. The authors used information from the Cystic Fibrosis Foundation Patient Registry (CFFPR), which has collected longitudinal data on approximately 90% of cystic fibrosis patients diagnosed in the United States since 1986. They developed multivariate logistic regression models by using data on 5,820 patients randomly selected from 11,630 in the CFFPR in 1993. Models were tested for goodness of fit and were validated for the remaining 5,810 patients for 1993. The validated 5-year survivorship model included age, forced expiratory volume in 1 second as a percentage of predicted normal, gender, weight-for-age z score, pancreatic sufficiency, diabetes mellitus, Staphylococcus aureus infection, Burkerholderia cepacia infection, and annual number of acute pulmonary exacerbations. The model provides insights into the complex nature of cystic fibrosis and supplies a rigorous tool for clinical practice and research.

Outcomes of intensive care unit care in adults with cystic fibrosis

Cystic fibrosis (CF) causes progressive respiratory failure and death in more than 90% of patients. Mechanical ventilation has been discouraged in CF because of poor outcomes, but improved survival and the availability of lung transplantation have increased the indications for care of CF patients in the intensive care unit (ICU). We studied the outcomes of all CF patients admitted to the University of North Carolina Hospitals Medical ICU from January 1990 through December 1998. Seventy-six patients, ranging in ages from 17 to 45 yr (mean: 27 yr), and of whom 53% were female, had 136 admissions for exacerbations of CF with respiratory failure (RF, n = 65), hemoptysis (n = 33), antibiotic desensitization (n = 30), pneumothorax (n = 3), or other reasons (n = 5). Eighty-six percent of the patients with hemoptysis and all of those with desensitization and pneumothorax were alive 1 yr after ICU discharge. Of the 42 patients with RF, 37 (88%) required assisted ventilation. Twenty-three (55%) of the patients with RF survived to ICU discharge and 19 (45%) died. Seventeen (40%) of the patients with RF received lung transplants and 14 were alive 1 yr later. Without transplantation, three (7%) of the patients with RF were alive and three (7%) were dead 1 yr later. Sex, body mass index, and respiratory bacteria did not correlate with survival. We conclude that ICU care for adults with CF who have reversible complications is appropriate and effective. Ventilatory support is appropriate for some transplant candidates.

Pseudomonas aeruginosa and the in vitro and in vivo biofilm mode of growth

The biofilm mode of growth is the survival strategy of environmental bacteria like Pseudomonas aeruginosa. Such P. aeruginosa biofilms also occur in the lungs of chronically infected cystic fibrosis patients, where they protect the bacteria against antibiotics and the immune response. The lung tissue damage is due to immune complex mediated chronic inflammation dominated by polymorphonuclear leukocytes releasing proteases and oxygen radicals.

Nocturnal oximetry in infants with cystic fibrosis

AIM

To investigate whether children with cystic fibrosis under 3 years of age have disordered breathing and episodes of oxygen desaturation during sleep.

METHODS

We studied 19 infants (9 boys and 10 girls) with cystic fibrosis, mean age 13.1 months (range 3-36 months) and 20 age and sex matched healthy subjects. Patients and controls underwent an overnight polysomnographic study and respiratory function testing on the following morning.

RESULTS

Seven patients with ongoing respiratory tract inflammation had disordered breathing and episodes of oxygen desaturation during sleep. Pulse oximetry showed a significantly lower mean oxygen saturation (SaO(2)) and a higher percentage of total sleep time spent with SaO(2) less than 93% in symptomatic children than in controls.

CONCLUSION

Results suggest that infants and young children with cystic fibrosis and mild airways inflammation (rhinitis, cough, red throat) have episodes of oxygen desaturation during sleep.

Prospects for the prevention and control of pseudomonal infection in children with cystic fibrosis

Most patients with cystic fibrosis (CF) experience recurrent and chronic endobronchial Pseudomonas aeruginosa infections. It is possible to prevent or delay the onset of these chronic infections in most patients with CF by eliminating cross-infection and by early aggressive antibiotic treatment of the first positive sputum culture and of subsequent intermittent colonisation. Lung tissue damage is caused by activation of the immunologically specific inflammatory defence mechanisms of the lungs, which are initiated by the antibody response and dominated by polymorphonuclear neutrophil leucocytes and their proteolytic and oxidative products. This inflammation induces a phenotypic shift from nonmucoid to mucoid, alginate-producing phenotypes of P. aeruginosa which then grow, endobronchially, as a biofilm. Such biofilms are impossible to eradicate with antibiotics. By using chronic suppressive antibiotic maintenance therapy and anti-inflammatory drugs it is however, possible to maintain the lung function of these patients for a number of years.

Superantigens and cystic fibrosis: resistance of presenting cells to dexamethasone

Staphylococcus aureus, a common pulmonary pathogen in cystic fibrosis (CF), produces exotoxins that are extremely potent superantigens. A number of animal studies have shown that superantigens cause pulmonary inflammation, but the possible role of superantigens in CF has not been investigated. The present study assessed possible differences between control and CF B cells in presenting superantigens to T cells. Immortalized B-cell lines were used as superantigen-presenting cells to avoid environmental influences (e.g., infection or antibiotics) common to freshly isolated cells. The results show that CF B-cell lines presented a staphylococcal superantigen to the immortalized T-cell line (Jurkat) as effectively as did control B-cell lines as measured by interleukin-2 production. However, in contrast to the case for control B-cell lines, dexamethasone did not inhibit CF B-cell lines from presenting superantigen. The resistance of superantigen-presenting CF B cells to corticosteroids suggests that the pulmonary response to superantigens may be poorly regulated in CF, leading to an exaggerated inflammatory response to S. aureus.

Newer therapies for cystic fibrosis

Cystic fibrosis (CF) is a chronic, progressive, genetic disease caused by flawed ion transport across epithelial membranes due to a genetic mutation. Most therapeutic efforts are centred on the main clinical manifestations of the disease: progressive destructive airway disease and pancreatic insufficiency. Most individuals with CF succumb to lung disease. The present-day therapeutic armamentarium includes agents that have been used for many decades, some of which have experienced transformations in their formulation or mode of administration thanks to the introduction of new manufacturing technologies. The development of new therapies involves new conceptual approaches, based on recent understanding of the disease. These therapies await proof of concept or clinical experimentation before being accepted as useful means to arrest the progression of the disease. In this article we will review therapeutic agents introduced into the clinical arsenal in the last 20 years, as well as experimental therapies under active investigation.

Risk of persistent growth impairment after alternate-day prednisone treatment in children with cystic fibrosis

BACKGROUND

It is uncertain whether the growth impairment that occurs in children during long-term treatment with glucocorticoids persists after the medication is discontinued and ultimately affects adult height.

METHODS

We evaluated growth six to seven years after alternate-day treatment with prednisone had been discontinued in 224 children 6 to 14 years of age with cystic fibrosis who had participated in a multicenter trial of this therapy from 1986 through 1991. Of the children, 151 had been randomly assigned to receive prednisone (either 1 or 2 mg per kilogram of body weight) and 73 to receive placebo. We obtained data on growth up to 1997 from the Cystic Fibrosis Foundation Patient Registry and standardized the data to sex- and age-specific norms from the National Center for Health Statistics. We used z scores to compare growth patterns among treatment groups.

RESULTS

In 1997, 68 percent of the patients were 18 years of age or older. The z scores for height declined during prednisone therapy; catch-up growth began two years after treatment with prednisone was discontinued. Among the boys, the z scores for height in those treated with prednisone remained lower than the scores for those who received placebo (P=0.02). The mean heights for boys 18 years of age or older were 4 cm less in the prednisone groups than in the placebo group, an equivalent of 13 percentile points (P=0.03). Among the girls, differences in height between those who were treated with prednisone and those who received placebo were no longer present two to three years after prednisone therapy was discontinued.

CONCLUSIONS

Among children with cystic fibrosis who have received alternate-day treatment with prednisone, boys, but not girls, have persistent growth impairment after treatment is discontinued.

Transport of bifunctional proteins across respiratory epithelial cells via the polymeric immunoglobulin receptor

Neutrophil elastase (NE) contributes to progression of the lung disease characteristic of cystic fibrosis (CF). We developed a strategy that permits the delivery of alpha(1)-antitrypsin (alpha(1)-AT) to inaccessible CF airways by targeting the respiratory epithelium via the polymeric immunoglobulin receptor (pIgR). A fusion protein consisting of a single-chain Fv directed against human secretory component (SC) and linked to human alpha(1)-AT was effectively transported in a basolateral-to-apical direction across in vitro model systems of polarized respiratory epithelium consisting of 16HBEo cells transfected with human pIgR complementary DNA, which overexpress the receptor, and human respiratory epithelial cells grown in primary culture at an air-liquid interface. When applied to the basolateral surface, the anti-SC Fv/alpha(1)-AT fusion protein penetrated the respiratory epithelia, with transcytosis of the fusion protein being related to the amount of SC detected at the apical surface. Significantly less fusion protein crossed the cells in the opposite direction. In addition, because the antihuman SC Fv/alpha(1)-AT fusion protein was transported vectorially and deposited into the small volume of apical surface fluid, the antiprotease component of this protein was concentrated atop the epithelium. Thus, in cell models, this system is capable of concentrating the antiprotease of the fusion protein, in the thin film of epithelial surface fluid to a level expected to be therapeutic in the airways of many patients with CF.

Oral steroids for cystic fibrosis

BACKGROUND

In cystic fibrosis, airway obstruction and recurrent respiratory infection leads to inflammation and eventually long term lung damage, (bronchiectasis), respiratory failure and death. Inflammation occurs early in the disease process, hence the rationale for the use of anti-inflammatory agents such as oral steroids.

OBJECTIVES

To assess the effectiveness of oral steroids in management of respiratory complications cystic fibrosis with particular regard to lung function and occurrence of adverse events. We aimed to to examine short term use for a respiratory exacerbation separately (up to 30 days) from long term anti-inflammatory use (greater than 30 days).

SEARCH STRATEGY

We searched The Cochrane Cystic Fibrosis and Genetic Disorders Group specialist trials register. Date of the most recent search of the Group's specialised register: November 1999.

SELECTION CRITERIA

All randomised or pseudorandomised trials comparing oral corticosteroids given for a period of five to 30 days for treatment of an exacerbation or for more than 30 days used long term, with placebo or no additional therapy in patients with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality.

MAIN RESULTS

Three trials were identified studying a total of 354 patients. Two of these were long term trials with four year follow up whilst one had follow up to 12 weeks only. There was a lack of data on our predefined outcomes with common outcomes examined at different time-points and also variations in the presentation of common outcomes. A meta-analysis was not possible. Oral corticosteroids at a prednisolone equivalent dose of 1 mg/kg alternate days appear to slow the progression of lung disease in cystic fibrosis. At 24 months from commencement, 70.4% patients treated with 1mg/kg prednisolone on alternate days had an increase in per cent predicted forced vital capacity (FVC) compared to 41.6% patients treated with placebo. The mean absolute change in per cent predicted forced expiratory volume at one second (FEV1) 48 months from commencement was -2% in the 1 mg/kg alternate days prednisolone group but -6% in the placebo group. In the long term, this benefit needs to be weighed against the occurrence of adverse events. Linear growth retardation was observed as early as six months from start of treatment in the 2 mg/kg alternate days prednisolone group and from 24 months of treatment in the 1 mg/kg alternate days prednisolone group. Occurrence of adverse events, particularly glucose abnormalities, cataracts and growth retardation resulted in early termination of one of the four year studies ( approximately approximately Eigen 1995 approximately approximately ), with the group taking 2 mg/kg prednisolone on alternate days being stopped first but followed by the 1 mg/kg alternate days.

REVIEWER'S CONCLUSIONS

Oral corticosteroids at a prednisolone equivalent dose of 1-2 mg/kg alternate days appear to slow the progression of lung disease in CF but this benefit needs to be weighed against the occurrence of adverse events, in particular, development of cataracts and effect on linear growth. A risk/benefit analysis of low-dose alternate days corticosteroids would be important and the role of short term use of oral steroids should be more fully evaluated.

IL-10 attenuates excessive inflammation in chronic Pseudomonas infection in mice

Cystic fibrosis (CF) lung disease is characterized by an excessive inflammatory response associated with chronic Pseudomonas aeruginosa endobronchial infection. Compared with bronchoalveolar lavage fluid from healthy subjects, lavage fluid from patients with CF contains elevated proinflammatory cytokines but negligible amounts of the anti-inflammatory cytokine interleukin-10 (IL-10). We sought to determine whether IL-10 deficiency results in increased local and systemic morbidity in mice with chronic endobronchial infection with P. aeruginosa embedded in agar beads and to determine if exogenous IL-10 might reduce these effects. Infected IL-10 knockout mice had more severe weight loss (p = 0.04) and increased area of lung inflammation (28 +/- 4 versus 10 +/- 2%, p < 0.002) but no alterations in bacterial burden compared with wild-type mice. Infected CD-1 mice treated with IL-10 had improved survival (p = 0. 035), less severe weight loss (p < 0.005), fewer bronchoalveolar lavage neutrophils (3 x 10(5)/ml versus 5 x 10(6)/ml, p < 0.02), and decreased area of lung inflammation (11 +/- 2 versus 35 +/- 7%, p < 0.01) but no alterations in bacterial burden compared with placebo-treated mice. These data suggest that IL-10 is an important regulator of the inflammatory response to P. aeruginosa endobronchial infection and that further investigation into the use of IL-10 in CF is warranted.

Patterns of medical practice in cystic fibrosis: part II. Use of therapies. Investigators and Coordinators of the Epidemiologic Study of Cystic Fibrosis

This report describes the prescribing pattern of therapeutic interventions in the management of patients with cystic fibrosis (CF), as observed in the Epidemiologic Study of Cystic Fibrosis (ESCF). Use of 20 therapies by 12,622 patients was recorded from each health care encounter (53,024 outpatient visits and 8,561 hospitalizations) during a 1-year period (1995), and analyzed by gender, age, severity of lung disease, and presence of any Pseudomonas species in the respiratory tract. The percentage of patients using the following pulmonary therapies was observed (in descending order): airway clearance techniques (88.2%); inhaled bronchodilators (82.2%); oral antibiotics (excluding quinolones) (68. 2%); dornase alfa (52.9%); intravenous antibiotics (34.4%); oral quinolones (34.4%); inhaled antibiotics (34.3%); mast cell stabilizers (29.5%); inhaled corticosteroids (25.9%); oral corticosteroids (17.1%); oral bronchodilators (16.2%); oxygen (8. 1%); inhaled mucolytic agent acetyl cysteine (6.5%); and diuretics (1.4%). The percentage of patients using nutritional therapies was: pancreatic enzymes (96%); oral nutritional supplements (31.1%); enteral nutrition (7.3%); and parenteral nutrition (0.7%). The percentage of patients using other therapies was: nonsteroidal anti-inflammatory drugs (7.9%); and insulin or oral hypoglycemic agents (6.1%). The general trend was for therapies to be used more by older patients, those with lower pulmonary function, and by those with Pseudomonas in their respiratory tract. Exceptions to this trend occurred for airway clearance, oral antibiotics, mast cell stabilizers, and pancreatic enzymes. Four therapies (oral nutritional supplements, parenteral nutrition, diuretics, and pancreatic enzymes) were used more by males than females. However, there was no gender difference for this group of therapies on pulmonary or nutritional status.

Quantitation of inflammatory responses to bacteria in young cystic fibrosis and control patients

Recent studies suggest that inflammation plays a role in the pathogenesis of lung disease in cystic fibrosis (CF). The goal of the present study was to quantitatively compare bronchoalveolar lavage fluid (BALF) inflammation and its relation to bacterial infection, between children with CF and children with other chronic respiratory problems. Differential cell counts, immunoreactive interleukin 8 (IL-8), and quantitative bacterial cultures were done in BALF from 54 CF (median age 1.8 yr) and 55 control patients (median age 1.0 yr) who underwent bronchoscopy for clinical indications. Among infected CF patients, those with Pseudomonas aeruginosa did not have more inflammation than those without P. aeruginosa. The ratio of neutrophils or of IL-8 to bacteria in BALF was significantly greater for CF patients compared with control subjects, regardless of pathogen. Calculation of linear regression for either neutrophils or IL-8, as a function of bacterial quantity, yielded positive slopes for both CF and control patients, but with significant elevations for CF. We conclude that the inflammatory response to bacterial infection is increased or prolonged in CF compared with control patients, and that this increase is not necessarily due to pathogens specific for CF (e.g., P. aeruginosa). These data may provide further rationale for anti-inflammatory therapy early in CF.

Pyloric channel stricture secondary to high-dose ibuprofen therapy in a patient with cystic fibrosis

OBJECTIVE

To describe a case of pyloric channel stricture secondary to high-dose ibuprofen therapy in a pediatric patient with cystic fibrosis.

CASE SUMMARY

A 12-year-old white girl started taking high-dose ibuprofen to treat the pulmonary manifestations of cystic fibrosis. The peak plasma concentration at dose initiation was within the accepted therapeutic range. Approximately one month later, the patient developed emesis and intolerance of solid foods, which persisted for several months and resulted in a weight loss of seven kilograms. The patient was referred to a pediatric gastroenterologist, who performed an upper endoscopy and subsequently diagnosed a pyloric channel stricture. The patient's pyloric channel was successfully dilated with two balloons. It is felt that the pyloric stricture developed from healing antral/pyloric channel ulcers. Ibuprofen was discontinued and omeprazole therapy was begun. Over the course of the following year, the patient was asymptomatic. Follow-up upper gastrointestinal barium swallows were normal.

DISCUSSION

When used for analgesia and fever in the pediatric population, ibuprofen has been shown to be a relatively safe drug. While it is known that ibuprofen may cause gastrointestinal adverse effects, the pediatric population is at lower risk; however, large doses of ibuprofen increase the risk of gastrointestinal adverse effects. The use of large doses of ibuprofen in the treatment of cystic fibrosis is a relatively new therapy. Limited data thus far in cystic fibrosis patients do not suggest increased risk of gastrointestinal complications.

CONCLUSIONS

Limited data to date indicate that ibuprofen, when used in large doses to treat the pulmonary manifestations of cystic fibrosis, is relatively safe. However, because of the potential risks to the gastrointestinal tract of high-dose ibuprofen therapy, clinicians should be aware of its possible complications.

The use of anti-inflammatory medications in cystic fibrosis: trends and physician attitudes

STUDY OBJECTIVES

In recent years, there has been considerable interest in the use of antiinflammatory medications to decrease airway inflammation and preserve pulmonary function in patients with cystic fibrosis (CF) lung disease. Long-term use of oral corticosteroids (OCS) and ibuprofen (IBU) has been proven efficacious in slowing the progression of CF. Inhaled corticosteroids (ICS) have not been adequately studied. Little is known regarding use trends and physician attitudes toward these drugs.

DESIGN

Cross-sectional survey mailed to 111 directors of Cystic Fibrosis Centers in the United States accredited by the Cystic Fibrosis Foundation. The two-page written questionnaire included items regarding physicians' attitudes toward anti-inflammatories, center demographics, patients receiving therapy, and number of physicians prescribing therapy.

RESULTS

Sixty-seven surveys were returned (60%). The responding centers represented 239 physicians and served 9,363 patients, 2,234 (24%) of whom were receiving routine antiinflammatory drugs. Complete data sets were available for 8,803 patients with 2,169 (25%) receiving anti-inflammatory therapy. Ninety-eight (41%) physicians prescribed long-term use of oral steroids for 413 (5%) patients, 103 (42%) prescribed inhaled steroids for 1,032 (12%) patients, and 108 (45%) prescribed high-dose IBU for 723 (8%) patients to control CF. The practitioners reported familiarity and efficacy as the primary reasons for prescribing OCS; concerns over side effects were the major reason for not prescribing. Regarding ICS, the primary reasons for prescribing were familiarity and safety, with lack of efficacy being cited as the major reason for not prescribing. For IBU, efficacy was ranked highest among reasons for prescribing, with concern over safety being the highest ranked reason for not prescribing.

CONCLUSIONS

Anti-inflammatory medications appear to be an underutilized therapeutic modality in CF care. This is true for numbers of patients receiving these drugs as well as numbers of care providers prescribing them. Additional studies will be required to address physicians' concerns regarding the long-term efficacy and safety of anti-inflammatory drugs in treating CF.