Effect of insulinlike growth factor-1 treatment in children with cystic fibrosis.

OBJECTIVES: Malnutrition is common in cystic fibrosis (CF) and adversely affects survival. Because insulinlike growth factor-1 (IGF-1) has insulinlike effects in terms of carbohydrate metabolism and is growth promoting, the authors hypothesized that its use would increase linear growth rate and decrease insulin requirements in children with CF. METHODS: The authors used a double-blind placebo-controlled crossover design. Seven prepubertal children aged 9.6 to 13 years (5 boys and 2 girls) were treated with placebo or IGF-1 for 6 months. After a 6-month washout period, patients received the alternative therapy for 6 months. The primary outcome measure was linear growth rate. Secondary outcome measures were changes in body mass index, body composition determined by dual energy x-ray absorptiometry, forced expiratory volume (FEV(1)), and the blood glucose/insulin ratio. RESULTS: The mean height z score at baseline was -1.5 +/- 0.8. At entry, the mean serum IGF-1 level was 124 +/- 25 ng/mL (normal range, 110-771 ng/mL). With treatment, mean serum IGF-1 levels increased twofold to threefold for all patients. The half-life for IGF-1 was 10.3 hours. We observed no significant difference in linear growth rate, weight gain, rate of accretion of lean body mass, or mean FEV(1) during treatment with IGF-1 compared with placebo. The glucose/insulin ratio, an indirect index of insulin sensitivity, was significantly increased with IGF-1 treatment compared with placebo ( P < 0.02). No adverse events related to IGF-1 were detected. CONCLUSIONS: Treatment with IGF-1 for 6 months did not promote linear growth in prepubertal children with CF. However, the glucose/insulin ratio was increased without changing blood glucose levels with IGF-1 treatment suggesting increased insulin sensitivity.

Serum and lower respiratory tract drug concentrations after tobramycin inhalation in young children with cystic fibrosis.

OBJECTIVES: To assess the serum and lower respiratory tract tobramycin concentrations (C(T)) produced by a single dose of tobramycin for inhalation delivered by a nebulizer and a compressor in patients with cystic fibrosis (CF) 6 months to 6 years of age. STUDY DESIGN: We performed a dose escalation study of serum C(T) measured before and 0.5, 1, 2, and 4 hours after a single dose of inhaled tobramycin, either 180 mg (10 patients) or 300 mg (19 patients). In a separate group of 12 patients, epithelial lining fluid (ELF) C(T) was measured by bronchoalveolar lavage 30 to 45 minutes after a 300-mg dose. RESULTS: A 180-mg dose of inhaled tobramycin produced a mean peak serum C(T) of 0.5 microg/mL (SD 0.4; range, <0.2 to 1.4 microg/mL). A 300-mg dose produced a mean peak serum C(T) of 0.6 microg/mL (SD 0.5; range, <0.2 to 1.2 microg/mL). These peak values are well below the accepted maximum trough concentration with parenteral dosing (2 microg/mL). The target ELF C(T) was 20 microg/mL, 10-fold greater than the minimal inhibitory concentration for most Pseudomonas aeruginosa isolates from very young patients with CF (2 microg/mL). Mean ELF C(T) was 90 microg/mL (SD 54; range, 16 to 204 microg/mL) and exceeded the target concentration in 11 patients. CONCLUSION: In patients with CF ages 6 months to 6 years, a single 300-mg dose of inhaled tobramycin appears to produce safe peak serum concentrations and drug concentrations in the bactericidal range in the lower respiratory tract.

Safety of aerosolized INS 365 in patients with mild to moderate cystic fibrosis: results of a phase I multi-center study.

Cystic fibrosis (CF) is characterized by defective cystic fibrosis transmembrane regulator (CFTR) expression and function, associated with abnormal ion transport and mucociliary clearance, and clinical lung disease. Triphosphate nucleotides such as uridine-5'-triphosphate (UTP) and INS 365, may be useful for CF through actions, mediated via P2Y(2) extracellular receptors, on chloride and liquid secretion, and ciliary beat frequency. INS 365 may offer chemical stability advantages over UTP. In a randomized, double-blind, multicenter phase I study, we studied the safety and maximally tolerated dose of escalating, single doses of aerosolized INS 365, in adult and pediatric patients with mild to moderate CF lung disease (FEV(1) > or = 45% predicted). In four successive dose cohorts of adult patients (n = 12 per cohort, age > or = 18 years) and four successive pediatric dose cohorts (n = 12 per cohort, age 5-12 years), patients were randomized 3:1 active/placebo (0.9% saline) to evaluate doses of 20, 40, 80, and 100 mg INS 365 delivered by nebulizer (Pari Star ). Sputum was collected pre- and post-dosing to obtain preliminary results on clinical efficacy. After each dose cohort, a Data Safety Monitoring Committee (DSMC) reviewed the data. Forty-eight adult and 36 pediatric patients completed the protocol (up to 100 mg for adults, 80 mg for pediatric patients). The predominant adverse events were cough, wheezing, chest tightness, and a decrease in FEV(1) (occurring in 8/48 adults, and 5/36 pediatric patients), which occurred predominantly in the 80-mg and 100-mg dose cohorts. Though a few adult patients had a tendency to increase sputum production, there was little consistent effect noted on sputum production in this acute, single-dose study. The data suggest that aerosolized INS 365 is safe when delivered at single doses of up to 40 mg in adults and children with CF, but that higher doses are unlikely to be tolerated.

Phenotype of CF and the effects of possible modifier genes.

Cystic fibrosis is an inherited multi-system disease, characterised by progressive lung disease and pancreatic insufficiency that is classically attributed to the dysfunction of a single gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). The widely diverse phenotypic expression of CF is likely influenced by other genetic traits separate from the CFTR locus or modifier genes. Many of the genes currently under study as potential modifiers of CF, particularly those which influence the severity of lung disease, are involved in the control of infection, immunity and inflammation. Some of these include HLA class II antigens, mannose-binding lectin, alpha(1)-antitrypsin and alpha(1)-antichymotrypsin, glutathione-S-transferase, nitric oxide synthase type I, TNF-alpha, TGF-beta, IL-1beta and IL-1Ra.

A protease-resistant catalase, KatA, released upon cell lysis during stationary phase is essential for aerobic survival of a Pseudomonas aeruginosa oxyR mutant at low cell densities.

A Pseudomonas aeruginosa oxyR mutant was dramatically sensitive to H(2)O(2), despite possessing wild-type catalase activity. Oxygen-dependent oxyR phenotypes also included an inability to survive aerobic serial dilution in Luria broth and to resist aminoglycosides. Plating the oxyR mutant after serial dilution in its own spent culture supernatant, which contained the major catalase KatA, or under anaerobic conditions allowed for survival. KatA was resistant to sodium dodecyl sulfate, proteinase K, pepsin, trypsin, chymotrypsin and the neutrophil protease cathepsin G. When provided in trans and expressed constitutively, the OxyR-regulated genes katB, ahpB, and ahpCF could not restore both the serial dilution defect and H(2)O(2) resistance; only oxyR itself could do so. The aerobic dilution defect could be complemented, in part, by only ahpB and ahpCF, suggesting that the latter gene products could possess a catalase-like activity. Aerobic Luria broth was found to generate approximately 1.2 microM H(2)O(2) min(-1) via autoxidation, a level sufficient to kill serially diluted oxyR and oxyR katA bacteria and explain the molecular mechanism behind the aerobic serial dilution defect. Taken together, our results indicate that inactivation of OxyR renders P. aeruginosa exquisitely sensitive to both H(2)O(2) and aminoglycosides, which are clinically and environmentally important antimicrobials.

Current concepts on pulmonary host defense mechanisms in children.

The respiratory tract is exposed continuously to noxious agents, microbial organisms, particles, and allergens. It has therefore evolved both innate and specific defense mechanisms. The innate host defense mechanisms include components such as collectins, beta-defensins, lactoferrin, and complement, all of which have an important role in modulating the immune response. Immune protection of the lungs by specific antibody is reviewed. The airways are protected by alveolar macrophages, neutrophils, and lymphocytes, and their origins, regulation, functions, and antimicrobial activity are summarized. Antimicrobial peptides and immune-modulating peptides are likely to have a significant therapeutic role for infection and inflammation in the respiratory tract.

Mercaptoethylguanidine inhibits the inflammatory response in a murine model of chronic infection with Pseudomonas aeruginosa.

Chronic airway inflammation induced by Pseudomonas aeruginosa is the eventual cause of respiratory failure in most people affected by cystic fibrosis. Recent evidence implicates the involvement of free radical and oxidant stress in the pathogenesis of the inflammatory injury. Here we report the efficacy of a novel experimental therapeutic, mercaptoethylguanidine (MEG), which has combined actions as a selective inhibitor of the inducible nitric oxide synthase and as a scavenger of peroxynitrite, a potent oxidant formed in the reaction of nitric oxide and superoxide radical. Chronic pulmonary infection was established in FVB/N mice by intratracheal administration of 10(5) colony-forming units of P. aeruginosa in agar beads. Treatment with MEG (10 mg/kg/dose every 8 h i.p.) inhibited weight loss in the first 3 days and reduced histologic injury at 8 days postinfection. MEG also reduced myeloperoxidase activity, a marker of neutrophil infiltration, at 8 days and concentrations of the proinflammatory cytokines interleukin-1beta, tumor necrosis factor-alpha, and macrophage inflammatory protein 2 in whole lung homogenates. MEG-treated animals and controls had similar perioperative mortality and comparable colony counts of P. aeruginosa at 8 days, indicating that MEG did not exacerbate infection. Our data suggest that MEG may be an effective immunomodulatory therapy of pulmonary inflammation induced by chronic infection.

Interleukin-1 receptor antagonist inhibits interleukin-8 expression in A549 respiratory epithelial cells infected in vitro with a replication-deficient recombinant adenovirus vector.

In an earlier study, we showed that a recombinant adenovirus vector with deletions in the E1 and E3 regions of the viral genome (AV1LacZ4) induces expression of interleukin (IL)-8 in A549 cells (a human respiratory cell line). IL-8 can be induced through several pathways, including activation by IL-1. We tested the hypothesis that the induction of IL-8 by the AV1LacZ4 adenovirus is accomplished by means of the IL-1/IL-8 activation pathway, which could be blocked by IL-1 receptor antagonist (IRAP). Viral infections of A549 cells were performed at a multiplicity of infection (MOI) of 50 in the presence and absence of IRAP (50 ng/ml). A549 cells were also stimulated with tumor necrosis factor (TNF)-alpha (100 ng/ml), a known stimulant of IL-8, in the presence and absence of IRAP. IL-8 expression was evaluated by Northern blot analysis and enzyme-linked immunosorbent assay. Levels of IL-8 protein and messenger RNA (mRNA) were greater in the infected cells than in the uninfected ones at 24, 48, and 96 h (P < 0.01). Virus-infected cells treated with IRAP expressed 75% less IL-8 mRNA and protein (P < 0.01) than did untreated cells, whereas IRAP pretreatment of TNF-alpha-stimulated cells did not affect IL-8 production. IL-1 production by the virus-infected cells was detectable by concentration of the supernatants and reverse transcription-polymerase chain reaction. We conclude that IL-8 is produced by virus vector-infected cells, partly through IL-1 activation that can be downregulated by IRAP.

Generation of a transgenic mouse with lung-specific overexpression of the human interleukin-1 receptor antagonist protein.

The purpose of the studies described here was to test the hypothesis that overexpression of the human interleukin-1 receptor antagonist (IL-1ra) in the distal airway epithelia of mice would result in amelioration of the inflammatory effects of IL-1alpha. The coding region of the human IL-1ra gene was placed under transcriptional control of the 5' flanking region of the human SP-C gene. Transgenic mice were generated by pronuclear injection of the transgene and identified by Southern blot analysis of genomic DNA. RNA expression of the transgene was confirmed by Northern blot analysis. In order to determine whether expression of the transgene conferred protection against inflammatory stimuli, control and transgenic mice were treated with IL-1alpha by intratracheal instillation. Six hours after treatment, bronchoalveolar lavage was performed, which revealed a statistically significant decrease in the degree of neutrophilia in the transgenic mice as compared with control mice. Furthermore, there was a significant reduction in the whole-lung myeloperoxidase concentration. Reverse transcription-polymerase chain reaction analysis of whole-lung RNA revealed a significant reduction in the messenger RNA/beta-actin ratio of macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-2 in the transgenic animals as compared with controls. The results of these studies indicate that distal airway epithelial cell expression of human IL-1ra results in partial protection from IL-1alpha-induced airway inflammation and injury.

Predictors of total body bone mineral density in non-corticosteroid-treated prepubertal children with juvenile rheumatoid arthritis.

OBJECTIVE: To determine the extent of significant osteopenia in prepubertal patients with juvenile rheumatoid arthritis (JRA) not treated with corticosteroids and to identify variables that are highly related to bone mineralization in this population. METHODS: In a cross-sectional study, 48 JRA patients and 25 healthy control subjects ages 4.6-11.0 years were evaluated. Total body bone mineral density (TB BMD) was determined by Hologic dual energy x-ray absorptiometry. All patients were prepubertal (Tanner stage I or II) and had never taken corticosteroids. For comparison, JRA patients were divided into "low" TB BMD (Z score < or =-1) or "normal" TB BMD (Z score >-1). RESULTS: The overall mean +/- SD TB BMD scores did not differ between the JRA subjects (0.75 +/- 0.06 gm/cm2) and controls (0.73 +/- 0.07 gm/cm2; P > 0.30). However, 29.2% of the JRA patients had low TB BMD, whereas only 16% would be expected to have low TB BMD based on the standard normal distribution (goodness of fit chi(2) = 4.84, P = 0.01). The mean Z score for the JRA patients with low TB BMD was -1.43, and for those with normal TB BMD, it was 0.32. The JRA subjects with low TB BMD were significantly younger, had more active articular disease, greater physical function limitation, higher erythrocyte sedimentation rate, higher joint count severity score, lower body mass index, lower lean body mass, less participation in organized sports, and more protein and vitamin D in their diet compared with JRA patients with normal TB BMD (all P < 0.05). Using logistic regression, a model including age at JRA onset, Juvenile Arthritis Functional Assessment Report (JAFAR) score, triceps skin-fold percentiles, percentage US recommended daily allowance for dietary magnesium intake, and serum 1,25-dihydroxyvitamin D levels was able to accurately segregate 79.6% of the JRA subjects into either the low or normal TB BMD groups (chi(2) = 20.5, P = 0.001). CONCLUSION: This study demonstrated that in a mildly to moderately ill prepubertal JRA population that had never been exposed to corticosteroids, almost 30% had significantly low TB BMD. The patients with low TB BMD had more active and severe articular disease and greater physical function limitation. Disease-related parameters in JRA appear to exert a negative effect on bone mineralization even in prepubertal children, which can be demonstrated despite the exclusion of corticosteroid-treated patients.

Use of bronchoalveolar lavage semiquantitative cultures in cystic fibrosis.

To assess bronchoalveolar lavage (BAL) in adult CF patients with respiratory symptoms, we studied BAL fluid (BALF) culture results from 28 bronchoscopies in 11 patients. Patients were asked to provide sputum for culture. All but two patients were receiving antibiotics at the time of bronchoscopy, with 13 bronchoscopies done on patients who had been receiving antibiotics for more than 10 d. Gram stain of the BALF was positive in 18 cases. In all but one BALF, > 10,000 colony-forming units per milliliter (cfu/ml) BALF of one or more pathogens was identified. The final case grew Burkholderia cepacia, which was not grown in the sputum. In only six cases (21%) were the sputum and BALF culture results the same. Prior to 11 bronchoscopies, the sputum was not adequate. The remaining 11 cases either had different pathogens in the BAL (six cases), or had some but not all of the BALF pathogens in the sputum. BALF cultures changed therapy in 13 (48%) of cases. Semiquantitative culture of BALF was a useful diagnostic tool in CF in patients in whom empiric therapy failed.

Safety of repeated intermittent courses of aerosolized recombinant human deoxyribonuclease in patients with cystic fibrosis.

OBJECTIVES: To determine the effect of repeated doses of aerosolized recombinant human deoxyribonuclease (rhDNase) on the development of anti-rhDNase antibodies, acute allergic reactions, and pulmonary function in patients with cystic fibrosis. DESIGN: A multicenter, open-label study in which 184 patients received 10 mg aerosolized rhDNase twice a day for 14 days followed by a 14-day washout period for a total of 6 treatment cycles. Serial determinations of anti-rhDNase antibodies and pulmonary functions were performed. RESULTS: Detectable anti-rhDNase antibodies developed in 16 (8.7%) patients. These patients had no changes in their symptoms from the time they entered the trial. Antibodies detected were all of the IgG isotype. Increases in both forced expired volume in 1 second and forced vital capacity were noted from the beginning to the end of each cycle of treatment returning to baseline during the off-treatment period of each cycle. Seropositivity to rhDNase was not associated with allergic reactions and had no relationship on improvement in pulmonary function. CONCLUSIONS: Development of anti-rhDNase antibodies occurred in a small number of patients and was not associated with side effects. Intermittent administration of rhDNase for 24 weeks to patients with cystic fibrosis was well tolerated and was not associated with anaphylaxis in any patient. Pulmonary function improved significantly during the 14-day cycles while rhDNase was administered and returned to baseline when rhDNase was discontinued.

A pilot study of the predictive value of plasma tumor necrosis factor alpha and interleukin 1 beta for Streptococcus pneumoniae bacteremia in febrile children.

OBJECTIVE: To determine the value of tumor necrosis factor alpha (TNF) and interleukin 1 beta (IL1) levels in predicting Streptococcus pneumoniae bacteremia in nontoxic-appearing, febrile children who do not have a bacterial source for their fever on physical examination. METHODS: A prospective, nested case-control study was conducted in a children's hospital ED. All febrile children < 3 years old who were believed to be immunocompetent and not in shock, had no obvious bacterial source for their fever on physical examination, and had a blood culture obtained were eligible. Plasma obtained at the time of the blood culture was available for analysis by enzyme-linked immunosorbent assays for TNF and IL1. Children who had positive blood cultures for Streptococcus pneumoniae were the cases. The controls were selected from children who had negative blood cultures. RESULTS: During a 1-year period, 12 cases and 65 controls were identified. There was no significant difference in age, height or duration of fever, or illness acuity between the groups. The following were used as threshold values for positive test: white blood cell (WBC) count > 15.0 x 10(9) cells/L, TNF > 21.5 ng/mL, and IL1 > 9.0 ng/mL. Using an estimated prior probability of bacteremia of 4%, the positive predictive value (PPV) and the negative predictive value (NPV) for bacteremia were 11.7% and 98.6% using the WBC count, 11.1% and 98.6% using the IL1 level, and 9.0% and 98.9% using the TNF level. The combination of WBC count with either TNF or IL1 gave an NPV of 100%, with PPVs of 8.5% for TNF and 9.9% for IL1. CONCLUSIONS: Like the WBC count, TNF and IL1 are good negative but poor positive predictors of Streptococcus pneumoniae bacteremia in nontoxic-appearing, febrile children. At present, the addition of plasma TNF or IL1 levels would add little to emergency physicians' ability to predict Streptococcus pneumoniae bacteremia. However, as the quantification of these cytokines becomes more rapid, available, and standardized, and more knowledge of TNF and IL1 levels during various illnesses is gained, their utility in the clinical setting for ruling out bacteremia should be further assessed.

Comparison between morphologic changes seen on high-resolution CT and regional pulmonary perfusion seen on SPECT in patients with cystic fibrosis.

OBJECTIVE: To evaluate the relationship between morphologic findings seen on high-resolution computed tomography (HRCT) of the lung and regional lung perfusion depicted on single photon-emission computed tomography (SPECT) pulmonary perfusion imaging in patients with cystic fibrosis. MATERIALS AND METHODS: Ten HRCT and 10 technetium-99 m macroaggregated albumin SPECT pulmonary perfusion imaging studies were performed on eight young adult patients who were considered to be clinically well and have mild to moderate cystic fibrosis. HRCT scans of the chest were evaluated using a CT scoring system which included grading of bronchiectasis, peribronchial thickening, hyperlucency, bullae, collapse/consolidation, and mucus plugging. Each lung was divided into six anatomic zones which were independently scored. A lung perfusion score (between 0 and 100), reflecting the percentage of compromised lung, was estimated for each zone. Axial lung perfusion SPECT images were matched anatomically to HRCT images. Lung function was considered compromised when the counts per pixel were less than 25 % of the count level seen in an area of the same patient's lung which was judged to be normal. RESULTS: There was a statistically significant relationship (P = 0.0001) between HRCT total scores and SPECT lung perfusion scores as well as between hyperlucency scores by HRCT and the SPECT lung perfusion scores. However, the HRCT score was a poor predictor of the lung perfusion score in zones with intermediate HRCT scores, which constituted 106 of 120 zones. CONCLUSION: Morphologic changes depicted by HRCT correlate with decreased lung pefusion on SPECT. However, HRCT changes accurately predict regional lung function only in the most normal and severely diseased lung zones.

Resting energy expenditure, pulmonary inflammation, and genotype in the early course of cystic fibrosis.

To further investigate the early course of cystic fibrosis (CF), specifically to examine factors contributing to energy imbalance, we examined resting energy expenditure (REE) (by indirect calorimetry) per unit body weight and metabolically active body cell mass (by total body potassium), in relation to CF genotype (by genomic DNA analysis), CF pancreatic phenotype, and markers of pulmonary inflammation (from bronchoalveolar lavage fluid). Eighteen subjects with presymptomatic CF who were less than 2 years of age (n = 11, delta F508/ delta F508 genotype; n = 15, pancreatic insufficiency phenotype), identified by newborn screening, were compared with age-, sex-, and length-matched control subjects (n = 13). Those with the delta F508/ delta F508 genotype had significantly higher mean REE expressed per unit body weight (125%) and body cell mass (115%; p < 0.03). Those with other genotypes (n = 7) did not, as a group, have significantly different mean REEs, but individuals with known "severe" genotypes had REEs in the high range and those with a pancreatic-sufficient phenotype had significantly lower REE than those with a pancreatic-insufficient phenotype (p < 0.05), and REEs were in the normal range. Examination of bronchoalveolar lavage fluid revealed positive culture results (7/10) but variable colony counts, neutrophil percentages, and concentrations of interleukin-8 and interleukin-1 beta equally in both CF genotype groups. These markers of pulmonary inflammation were not correlated, individually or collectively, with REE or genotype. We conclude that genotypic variations in energy balance are detectable early in CF unrelated to lung inflammation. Subclinical defects in body composition and pulmonary integrity occur early in CF and, in combination with increased cellular metabolic activity, have important clinical implications with respect to early diagnosis and management.