Progression of pulmonary hyperinflation and trapped gas associated with genetic and environmental factors in children with cystic fibrosis

BACKGROUND: Functional deterioration in cystic fibrosis (CF) may be reflected by increasing bronchial obstruction and, as recently shown, by ventilation inhomogeneities. This study investigated which physiological factors (airway obstruction, ventilation inhomogeneities, pulmonary hyperinflation, development of trapped gas) best express the decline in lung function, and what role specific CFTR genotypes and different types of bronchial infection may have upon this process. METHODS: Serial annual lung function tests, performed in 152 children (77 males; 75 females) with CF (age range: 6-18 y) provided data pertaining to functional residual capacity (FRCpleth, FRCMBNW), volume of trapped gas (VTG), effective specific airway resistance (sReff), lung clearance index (LCI), and forced expiratory indices (FVC, FEV1, FEF50). RESULTS: All lung function parameters showed progression with age. Pulmonary hyperinflation (FRCpleth > 2SDS) was already present in 39% of patients at age 6-8 yrs, increasing to 67% at age 18 yrs. The proportion of patients with VTG > 2SDS increased from 15% to 54% during this period. Children with severe pulmonary hyperinflation and trapped gas at age 6-8 yrs showed the most pronounced disease progression over time. Age related tracking of lung function parameters commences early in life, and is significantly influenced by specific CFTR genotypes. The group with chronic P. aeruginosa infection demonstrated most rapid progression in all lung function parameters, whilst those with chronic S. aureus infection had the slowest rate of progression. LCI, measured as an index of ventilation inhomogeneities was the most sensitive discriminator between the 3 types of infection examined (p < 0.0001). CONCLUSION: The relationships between lung function indices, CFTR genotypes and infective organisms observed in this study suggest that measurement of other lung function parameters, in addition to spirometry alone, may provide important information about disease progression in CF.

Chemokines indicate allergic bronchopulmonary aspergillosis in patients with cystic fibrosis

RATIONALE: Allergic bronchopulmonary aspergillosis (ABPA) is characterized by a Th2 immune response. Mouse models suggest a critical role for the Th2 chemokines thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in ABPA. OBJECTIVES: To determine whether serum levels of TARC and MDC characterize ABPA in patients with cystic fibrosis (CF) and to examine longitudinally if levels of TARC and MDC indicate ABPA exacerbations in patients with CF. METHODS: Levels of TARC and MDC and levels of Th1 (IL-12 and IFN-gamma) and Th2 (IL-4, IL-5, and IL-13) cytokines were analyzed in serum of 16 patients with CF with ABPA, six non-CF patients with asthma with ABPA, 13 patients with CF colonized with Aspergillus fumigatus, six patients with CF sensitized to A. fumigatus, 12 atopic patients with CF, and 13 non-CF atopic control subjects by ELISA. The longitudinal course of TARC, MDC, and IgE levels was assessed during ABPA episodes. RESULTS: Patients with ABPA had significantly higher serum levels of TARC compared with the other patient groups. Cytokine levels did not differ among the patient groups. Longitudinally, levels of TARC indicated ABPA exacerbations in patients with CF more clearly than IgE levels. In patients with CF and ABPA, levels of TARC correlated positively with specific IgE to A. fumigatus and rAsp f4. CONCLUSIONS: Serum levels of TARC differentiate patients with CF or patients with asthma with ABPA from patients with CF colonized with or sensitized to A. fumigatus, atopic patients with CF, and atopic control subjects. Longitudinally, levels of TARC indicate ABPA exacerbations, suggesting TARC as a marker for identification and monitoring of ABPA in patients with CF.

alpha1-Antitrypsin inhalation reduces airway inflammation in cystic fibrosis patients

The airways of cystic fibrosis (CF) patients are characterised by neutrophils that release high amounts of elastase overwhelming the local antiprotease shield. Inhalation of alpha(1)-antitrypsin (AAT) may restore the protease-antiprotease balance and attenuate airway inflammation in CF airways. The aims of the present study were: 1) to assess the best deposition region for inhaled AAT by two different inhalation strategies; and 2) to examine the effect of 4 weeks of AAT inhalation on lung function, protease-antiprotease balance and airway inflammation in CF patients. In a prospective, randomised study, 52 CF patients received a daily deposition by inhalation of 25 mg AAT for 4 weeks targeting their peripheral or bronchial compartment. The levels of elastase activity, AAT, pro-inflammatory cytokines, neutrophils, immunoglobulin G fragments and the numbers of Pseudomonas aeruginosa were assessed in induced sputum before and after the inhalation period. Inhalation of AAT increased AAT levels and decreased the levels of elastase activity, neutrophils, pro-inflammatory cytokines and the numbers of P. aeruginosa. However, it had no effect on lung function. No difference was found between the peripheral and bronchial inhalation mode. In conclusion, although no effect on lung function was observed, the clear reduction of airway inflammation after alpha(1)-antitrypsin treatment may precede pulmonary structural changes. The alpha(1)-antitrypsin deposition region may play a minor role for alpha(1)-antitrypsin inhalation in cystic fibrosis patients.

Clonal analysis of Inquilinus limosus isolates from six cystic fibrosis patients and specific serum antibody response

Inquilinus limosus is a novel Gram-negative bacterium of the subdivision alpha-Proteobacteria recently found in the airways of patients with cystic fibrosis (CF). Here, the authors report on the clinical courses of six CF patients colonized with I. limosus. Five patients suffered from either an acute respiratory exacerbation or a progressive loss of pulmonary function, whereas one patient was in a stable clinical situation. This study focused on two aims: (i) the clonal analysis of I. limosus isolates by random amplified polymorphic DNA (RAPD)-PCR, and (ii) the clarification of whether the presence of I. limosus in the respiratory tract is associated with a specific serum antibody response. Serum IgG was detected by immunoblotting using I. limosus whole-cell-lysate proteins as antigens. Sera from healthy blood donors (n=10) and from CF patients colonized with Pseudomonas aeruginosa (n=10) were found to be immunoblot negative. All six Inquilinus-positive patients raised serum IgG antibodies against various I. limosus antigens. Surprisingly, in one patient, a specific I. limosus serum antibody response was already detected 1 year prior to Inquilinus-positive sputum cultures. Two prominent antigens were characterized by MALDI-MS: a 23 kDa protein revealed homology to the outer membrane lipoprotein OmlA of Actinobacillus pleuropneumoniae, and an 18 kDa protein to a protein-tyrosine phosphatase of Burkholderia cepacia. In conclusion, detection of I. limosus is accompanied by a specific serum antibody response and may reflect the infectious/pathogenic potential of I. limosus. Moreover, IgG immunoblotting may be useful to detect early infection with I. limosus and may support the selective cultivation of this novel emerging pathogen.

Comparison of serum markers for allergic bronchopulmonary aspergillosis in cystic fibrosis

The diagnosis of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) is a challenge. Thymus- and activation-regulated chemokine (TARC) has recently been reported to play a role in ABPA. The aim of this study was to compare the diagnostic value of TARC with that of known serological markers for diagnosis of ABPA in CF patients. The present study longitudinally followed 48 CF patients, of whom 12 had a diagnosis of ABPA according to Nelson's criteria, for 1-8 yrs with repeated measurements of serum total immunoglobulin (Ig)E, specific Aspergillus fumigatus IgE and IgG, specific IgE against recombinant A. fumigatus allergens (rAsp f) 1, 3, 4 and 6, and TARC. Median (interquartile range) TARC levels were 589 (465-673) pg x mL(-1) in ABPA patients and 232 (189-289) pg x mL(-1) in non-ABPA patients. Receiver operating characteristic curves revealed that TARC was superior to the other markers for diagnosis of ABPA. Diagnostic accuracy was greater for TARC (93%) than for total IgE (74%), or rAsp f 4 (75%) or f 6 (79%). The present study indicates that thymus- and activation-regulated chemokine may be useful in the diagnosis of allergic bronchopulmonary aspergillosis in cystic fibrosis patients. However, larger studies are needed before thymus- and activation-regulated chemokine can routinely be used in diagnostic algorithms.

Innovative chemotherapeutical treatment options for alveolar and cystic echinococcosis

Echinococcus granulosus and Echinococcus multilocularis are cestode parasites, of which the metacestode (larval) stages cause the diseases cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively. Albendazole and mebendazole are presently used for chemotherapeutical treatment. However, these benzimidazoles do not appear to be parasiticidal in vivo against AE. In addition, failures in drug treatments as well as the occurrence of side-effects have been reported. New drugs are needed to cure AE and CE, which are considered to be neglected diseases. Strategies currently being implemented to identify novel chemotherapeutical treatment options include (i) conventional primary in vitro testing of broad-spectrum anti-infective drugs, either in parallel with, or followed by, animal experimentation; (ii) studies of drugs which interfere with the proliferation of cancer cells and of Echinococcus metacestodes; (iii) exploitation of the similarities between the parasite and mammalian signalling machineries, with a special focus on targeting specific signalling receptors; (iv) in silico approaches, employing the current Echinococcus genomic database information to search for suitable targets for compounds with known modes of action. In the present article, we review the efforts toward obtaining better anti-parasitic compounds which have been undertaken to improve chemotherapeutical treatment of echinococcosis, and summarize the achievements in the field of host-parasite interactions which may also lead to new immuno-therapeutical options.

Post-surgical follow-up (by ELISA and immunoblotting) of cured versus non-cured cystic echinococcosis in young patients

The study was designed to determine comparatively the prognostic value of immunoblotting and ELISA in the serological follow-up of young cystic echinococcosis (CE) patients exhibiting either a cured or a progredient (non-cured) course of disease after treatment. A total of 54 patients (mean age 9 years, range from 3 to 15 years) with surgically, radiologically and/or histologically proven CE were studied for a period up to 60 months after surgery. Additionally, some of the patients underwent chemotherapy. Based on the clinical course and outcome, as well as on imaging findings, patients were clustered into 2 groups of either cured (CCE), or non-cured (NCCE) CE patients. ELISA showed a high rate of seropositivity 4 to 5 years post-surgery for both CCE (57.1%) and NCCE (100%) patients, the difference found between the two groups was statistically not significant. Immunoblotting based upon recognition of AgB subcomponents (8 and 16 kDa bands) showed a decrease of respective antibody reactivities after 4 years post-surgery. Only sera from 14.3% of CCE patients recognized the subcomponents of AgB after 4 years, while none (0%) of these sera was still reactive at 5 years post-surgery. At variance, immunoblotting remained positive for AgB subcomponents in 100% of the NCCE cases as tested between 4 and 5 years after surgical treatment. Immunoblotting therefore proved to be a useful approach for monitoring post-surgical follow-ups of human CCE and NCCE in young patients when based upon the recognition of AgB subcomponents.

Cystic adventitial disease of the popliteal artery: an argument for the developmental theory

Cystic adventitial disease is a rare non-atheromatous cause of popliteal artery disease. We report a case of a 54-year-old patient with claudication of the right calf caused by cystic adventitial disease. Intra-operatively, a communication between the adventitia and the knee joint was identified. Connections between the adventitial cyst and the nearby joint have been reported in the literature that support the developmental theory. This theory suggests that cystic adventitial disease is a developmental manifestation of mucin-secreting cells derived from the mesenchyme of the adjacent joint. This case is the first, to our knowledge, in which a communication between joint and adventitia has been clearly documented by operative findings.

Cleavage of CXCR1 on neutrophils disables bacterial killing in cystic fibrosis lung disease

Interleukin-8 (IL-8) activates neutrophils via the chemokine receptors CXCR1 and CXCR2. However, the airways of individuals with cystic fibrosis are frequently colonized by bacterial pathogens, despite the presence of large numbers of neutrophils and IL-8. Here we show that IL-8 promotes bacterial killing by neutrophils through CXCR1 but not CXCR2. Unopposed proteolytic activity in the airways of individuals with cystic fibrosis cleaved CXCR1 on neutrophils and disabled their bacterial-killing capacity. These effects were protease concentration-dependent and also occurred to a lesser extent in individuals with chronic obstructive pulmonary disease. Receptor cleavage induced the release of glycosylated CXCR1 fragments that were capable of stimulating IL-8 production in bronchial epithelial cells via Toll-like receptor 2. In vivo inhibition of proteases by inhalation of alpha1-antitrypsin restored CXCR1 expression and improved bacterial killing in individuals with cystic fibrosis. The cleavage of CXCR1, the functional consequences of its cleavage, and the identification of soluble CXCR1 fragments that behave as bioactive components represent a new pathophysiologic mechanism in cystic fibrosis and other chronic lung diseases.

Efficacy and safety of intravenous meropenem and tobramycin versus ceftazidime and tobramycin in cystic fibrosis

BACKGROUND: Cystic fibrosis (CF) is characterized by chronic bacterial broncho-pulmonary infection. Although intravenous (IV) antibiotic therapy is regarded as standard treatment in CF, only few randomised trials comparing different antibiotic compounds exist. METHODS: We report on a prospective multicenter interventional trial of IV meropenem (120 mg/kg/day) or IV ceftazidime (200-400 mg/kg/day), each administered together with IV tobramycin (9-12 mg/kg/day). Outcome measures were changes in lung function, microbiological sputum burden and blood inflammatory marker. Liver and renal function values were measured to assess safety. RESULTS: One hundred eighteen patients (59/59) were included into the study with the following indications: first infection of P. aeruginosa (n=6), acute pulmonary exacerbation (n=34) and suppression therapy of chronic P. aeruginosa colonization (n=78). Both treatments improved lung function measures, bacterial sputum burden and CRP levels with no differences between treatment groups observed. A significant higher elevation for alkaline phosphatase (p<0.0001) was observed for patients in the meropenem/tobramycin group. CONCLUSIONS: IV antibiotic therapy in CF patients with meropenem/tobramycin is as effective as with ceftazidime/tobramycin regarding lung function, microbiological sputum burden and systemic inflammatory status. Hepato-biliary function should be monitored carefully during IV treatment, possibly important in CF patients with pre-existing liver disease.

Nanoduct(R) sweat testing for rapid diagnosis in newborns, infants and children with cystic fibrosis

Determination of chloride concentration in sweat is the current diagnostic gold standard for Cystic Fibrosis (CF). Nanoduct(R) is a new analyzing system measuring conductivity which requires only 3 microliters of sweat and gives results within 30 minutes. The aim of the study was to evaluate the applicability of this system in a clinical setting of three children's hospitals and borderline results were compared with sweat chloride concentration. Over 3 years, 1,041 subjects were tested and in 946 diagnostic results were obtained. In 95 children, Nanoduct(R) failed (9.1% failure rate), mainly due to failures in preterm babies and newborns. Assuming 59 mmol/L as an upper limit of normal conductivity, all our 46 CF patients were correctly diagnosed (sensitivity 100%, 95% CI: 93.1-100; negative predicted value 100% (95% CI: 99.6-100) and only 39 non CF's were false positive (39/900, 4.3%; specificity 95.7%, 95%CI: 94.2-96.9, positive predicted value 54.1% with a 95%CI: 43.4-65.0). Increasing the diagnostic limit to 80 mmol/L, the rate fell to 0.3% (3/900). CF patients had a median conductivity of 115 mmol/L; the non-CF a median of 37 mmol/L. In conclusion, the Nanoduct(R) test is a reliable diagnostic tool for CF diagnosis: It has a failure rate comparable to other sweat tests and can be used as a simple bedside test for fast and reliable exclusion, diagnosis or suspicion of CF. In cases with borderline conductivity (60-80 mmol/L) other additional methods (determination of chloride and genotyping) are indicated.

Quality, size, and composition of pediatric endobronchial biopsies in cystic fibrosis

BACKGROUND: Studies on airway remodeling in children with cystic fibrosis (CF) may be hampered by difficulty in obtaining evaluable endobronchial biopsy specimens because of large amounts of mucus and inflammation in the CF airway. We prospectively assessed how the quality of biopsy specimens obtained from children with CF compare with those from children with other airway diseases. METHODS: Fiberoptic bronchoscopy with endobronchial biopsy was performed in 67 CF children (age range, 0.2 to 16.8 years), 34 children with wheeze/asthma (W/A), and 64 control children with chronic respiratory symptoms. Up to three biopsy specimens were taken and stained with hematoxylin and eosin. Biopsy specimen size and structural composition were quantified using stereology. RESULTS: At least one evaluable biopsy specimen was obtained in 72% of CF children, in 79% of children with W/A, and in 72% of control subjects (difference was not significant). The use of large biopsy forceps (2.0 mm) rather than small biopsy forceps (1.0 mm) [odds ratio (OR), 5.8; 95% confidence interval (CI), 1.1 to 29.8; p = 0.037] and the number of biopsy specimens taken (odds ratio, 2.6; 95% confidence interval, 1.3 to 5.2; p = 0.006) significantly contributed to the success rate. Biopsy size and composition were similar between groups, except that CF children and those patients with W/A had a higher percentage of the biopsy specimen composed of muscle than did control subjects (median 6.2% and 9.7% vs 0.9%, respectively; p = 0.002). CONCLUSIONS: Biopsy size and quality are adequate for the study of airway remodeling in CF children as young as 2 months of age. Researchers should use large forceps when possible and take at least two biopsy specimens per patient. An increased airway smooth muscle content of the airway mucosa may contribute to the pathophysiology of CF lung disease.