In Vitro Determination of Respimat® Dose Delivery in Children: An Evaluation Based on Inhalation Flow Profiles and Mouth-Throat Models.

BACKGROUND: Aerosol therapy in young children can be difficult. A realistic model based on handling studies and in vitro investigations can complement clinical deposition studies and be used to enable dose-to-the-lung (DTL) predictions. METHODS: Predictions on dose delivery to the lung were based on (1) representative inhalation flow profiles from children enrolled in a Respimat® handling study, (2) in vitro measurement of the fine-particle DTL using mouth-throat models derived from nuclear magnetic resonance/computed tomography (NMR/CT) scans of children, and (3) a mathematical model to predict the tiotropium DTL. Accuracy of the prediction was confirmed using pharmacokinetic (PK) data from children with cystic fibrosis enrolled in a phase 3 clinical trial of tiotropium Respimat with valved holding chamber (VHC). RESULTS: Representative inhalation flow profiles for each age group were obtained from 56 children who successfully inhaled a volume >0.15 L from the Respimat with VHC. Average dimensions of the mouth-throat region for 38 children aged 1-<2 years, 2-<3 years, 3-<4 years, and 4-<5 years were determined from NMR/CT scans. The DTL from the Respimat plus VHC were determined by in vitro measurement and were 5.1±1.1%, 15.6%±1.4%, 17.9%±1.5%, and 37.1%±1.8% of the delivered dose for child models 0-<2 years, 2-<3 years, 3-<4 years, and 4-<5 years, respectively. This provides a possible explanation for the age dependence of clinical PK data obtained from the phase 3 tiotropium trial. Calculated in vitro DTL per body mass (µg/kg [±SD]) were 0.031±0.014, 0.066±0.031, 0.058±0.024, and 0.059±0.029, respectively, compared to 0.046 in adults. Therefore, efficacy of the treatment was not negatively impacted in spite of the seemingly low percentages of the DTL. CONCLUSIONS: We conclude that the combination of real-life inhalation profiles with respective mouth-throat models and in vitro determination of delivered DTL is a good predictor of the drug delivery to children via the Respimat with VHC. The data provided can be used to support data from appropriate clinical trials.

Inhalation solutions--which ones may be mixed? Physico-chemical compatibility of drug solutions in nebulizers--update 2013.

Many patients suffering from chronic respiratory diseases rely on inhalation therapy with nebulizers. About 25% of patients who need to inhale several different drugs per day save time by mixing them for simultaneous inhalation. This review presents a comprehensive overview of the available data concerning physico-chemical compatibility of commonly mixed nebulizer solutions and suspensions. Information is based on our in vitro studies and a thorough literature search. Results indicate that many nebulizer solutions/suspensions are mixable without provoking incompatibilities. However, certain excipients contained in some of the tested drug products could be identified as a reason for incompatibilities, e.g. impaired activity of dornase alfa. Studies assessing the aerosol characteristics of compatible mixtures nebulized with commonly used nebulizers are limited and should be encouraged. The clinical efficacy of simultaneous inhalation of duplicate, tripartite or quadripartite mixtures must be evaluated in clinical studies before final recommendations for the inhalation regimens can be made.

Clinical characteristics of adults with slowly progressing mucopolysaccharidosis VI: a case series.

OBJECTIVE: To assess clinical features and general health status of adult patients with mucopolysaccharidosis (MPS) VI. METHODS: This report includes the clinical history of patients older than 18 years with slowly progressing MPS VI and the retrospective analysis of the outcomes of available data collected between September 2003 and October 2008 at the Center of Pediatric and Adolescent Medicine, University Medical Center, Johannes Gutenberg-University of Mainz, Germany. Variables included were urinary glycosaminoglycan (uGAG) level, mutation analysis, body height, forced vital capacity (FVC), 6-minute walk test, echocardiographic findings, the need for craniocervical decompression surgery, orthopaedic findings and ophthalmological assessments. RESULTS: The analysis included nine patients with MPS VI aged 19-29 years. The median age at diagnosis was 12 (range 6-20) years. At the time of the assessment (median age 25 years), median uGAG was 29 (range 15-149) µg/mg creatinine and median height 152 (range 136-161) cm. All patients had a FVC below standard values, seven showed reduced endurance in the 6-minute-walk test, all had valve changes with valve replacement in three, two underwent craniocervical decompression surgery, two underwent carpal tunnel surgery, five had ear/nose/throat (ENT) interventions, seven had hip pain/dysplasia, seven had corneal clouding and two were visually impaired. CONCLUSIONS: Although patients with slowly progressing MPS VI are a heterogeneous group showing disease manifestations in several organs, they seem to have some typical characteristics in common. Despite the attenuated clinical course, many of these patients show severe morbidity. Therefore, early diagnosis and proper follow-up and treatment are essential.

Mucopolysaccharidosis type II: European recommendations for the diagnosis and multidisciplinary management of a rare disease.

UNLABELLED: Mucopolysaccharidosis type II (MPS II) is a rare, life-limiting, X-linked recessive disease characterised by deficiency of the lysosomal enzyme iduronate-2-sulfatase. Consequent accumulation of glycosaminoglycans leads to pathological changes in multiple body systems. Age at onset, signs and symptoms, and disease progression are heterogeneous, and patients may present with many different manifestations to a wide range of specialists. Expertise in diagnosing and managing MPS II varies widely between countries, and substantial delays between disease onset and diagnosis can occur. In recent years, disease-specific treatments such as enzyme replacement therapy and stem cell transplantation have helped to address the underlying enzyme deficiency in patients with MPS II. However, the multisystem nature of this disorder and the irreversibility of some manifestations mean that most patients require substantial medical support from many different specialists, even if they are receiving treatment. This article presents an overview of how to recognise, diagnose, and care for patients with MPS II. Particular focus is given to the multidisciplinary nature of patient management, which requires input from paediatricians, specialist nurses, otorhinolaryngologists, orthopaedic surgeons, ophthalmologists, cardiologists, pneumologists, anaesthesiologists, neurologists, physiotherapists, occupational therapists, speech therapists, psychologists, social workers, homecare companies and patient societies. TAKE-HOME MESSAGE: Expertise in recognising and treating patients with MPS II varies widely between countries. This article presents pan-European recommendations for the diagnosis and management of this life-limiting disease.

A novel approach to CFTR mutation testing by pyrosequencing-based assay panels adapted to ethnicities.

BACKGROUND: Cystic fibrosis (CF) is a common autosomal recessive genetic disorder caused by a variety of sequence alterations in the CFTR gene [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)]. Because the relative prevalence of mutations strongly depends on the ethnic background, first-level testing of CF as defined by recent consensus recommendations ought to be adaptable to the ethnicity of patients. METHODS: We therefore developed and implemented a diagnostic approach to first-level testing for CF based on published mutation frequencies and Pyrosequencing (PSQ) technology that we complemented with standard procedures of mutation detection at the second level. RESULTS: The current test system of PSQ assays for 46 target CF mutations [including CFTRdele2,3 (21 kb) and 1342-6 (T)(n) (5T/7T/9T)] permits recombinations of single assays to optimize sensitivities for certain ethnicities. By easy expansion of the original mutation panel, the first-level test sensitivities with other ethnic groups would be increased, provided that the mutation frequencies are known. The test was validated with our local, ethnically mixed, but mainly German population (155 patients). The mutation-detection rate for the 92 patients whose CF was confirmed by the sweat test was 89.0% for the patients of German descent (73 of the 92 patients) and 73.7% for the patients of any other origin (19 of the 92 patients). Ethnicity-adapted testing panels for our foreign CF patients would increase the sensitivities for the respective groups by approximately 5%. CONCLUSIONS: PSQ-based genotyping is a reliable, convenient, highly flexible, and inexpensive alternative to conventional methods for first-level testing of CFTR, facilitating flexible adaptation of the analyzed mutation panel to any local ethnic group.

Physicochemical compatibility of mixtures of dornase alfa and tobramycin containing nebulizer solutions.

Patients suffering from cystic fibrosis (CF) often need to inhale multiple doses of different nebulizable drugs per day. Patients attempt to shorten the time consuming administration procedure by mixing drug solutions/suspensions for simultaneous inhalation. The objective of this experimental study was to determine whether mixtures of the nebulizer solution dornase alfa (Pulmozyme) with tobramycin nebulizer solutions (TOBI and GERNEBCIN 80 mg) are physico-chemically compatible. Drug combinations were prepared by mixing the content of one respule Pulmozyme with either one respule TOBI or one ampoule GERNEBCIN 80 mg. Test solutions were stored at room temperature and exposed to light. Dornase alfa activity and tobramycin concentrations were determined by using a kinetic colorimetric DNase activity assay and a fluorescence immunoassay, respectively. Physical compatibility was determined by visual inspection and measurements of pH and osmolality. Tobramycin concentration was not affected by mixing the drug products. In spite of the high variability of the dornase alfa potency assay, it is obvious that activity is especially affected by sodium metabisulfite, used as excipient in GERNEBCIN. Patients should be advised, not to mix Pulmozyme with GERNEBCIN because of the incompatibility reaction. Further analytical studies are needed in order to determine the integrity and activity of dornase alfa in mixtures of Pulmozyme with TOBI. Finally clinical studies are necessary in order to demonstrate equivalent efficacy and safety of simultaneous inhalation in comparison to consecutive inhalation of both drugs.

How pre- and postnatal risk factors modify the effect of rapid weight gain in infancy and early childhood on subsequent fat mass development: results from the Multicenter Allergy Study 90.

BACKGROUND: It is unclear which exposures may cause or modify the adverse effect of rapid weight gain on fat mass development in term children whose birth weight is appropriate-for-gestational age (AGA). OBJECTIVE: To determine which intrauterine or postnatal exposures increase the risk of or modify the effect of rapid weight gain on body fat percentage (BF%) and body mass index (BMI) trajectories between 2 and 6 y of age. DESIGN: Term AGA singletons (n = 370) from the German Multicenter Allergy Study (MAS-90), a longitudinal birth cohort study, with repeated anthropometric measurements until 6 y, and data on breastfeeding status, exposure to smoking during pregnancy, and maternal anthropometric and socioeconomic characteristics were included in this analysis. RESULTS: A shorter gestation [multivariate-adjusted odds ratio (OR): 5.12; 95% CI: 2.22, 11.82; P = 0.0001], being firstborn (OR: 2.01; 95% CI: 1.10, 3.69; P = 0.02), and having been bottle-fed (OR: 3.02; 95% CI: 1.68, 5.43; P = 0.0002) all significantly increased a child's risk of gaining weight rapidly, whereas a larger BMI at birth was protective (OR: 0.54; 95% CI: 0.38, 0.77; P = 0.0006). Multilevel model analyses showed that rapid growers exposed to tobacco in utero subsequently gained more BF% between 2 and 6 y than did rapid growers who had not been exposed (beta +/- SE: 0.78 +/- 0.28%/y; P = 0.005). Similarly, change in BF% was greater in rapid growers with an overweight mother than in those with a normal-weight mother (1.01 +/- 0.30%/y; P = 0.0007). CONCLUSIONS: The occurrence of rapid weight gain between birth and 2 y and the magnitude of its effect on BF% development in AGA children is influenced by both intrauterine and postnatal exposures.

Dysfunction of the non-neuronal cholinergic system in the airways and blood cells of patients with cystic fibrosis.

The non-neuronal cholinergic system is widely expressed in human airways, skin and immune cells. Choline acetyltransferase (ChAT), acetylcholine and nicotine/muscarine receptors are demonstrated in epithelial surface cells, submucosal glands, airway smooth muscle fibres and immune cells. Moreover, acetylcholine is involved in the regulation of cell functions like proliferation, differentiation, migration, organization of the cytoskeleton, cell-cell contact, secretion and transport of ions and water. Cystic fibrosis (CF), the most frequent genetic disorder, is known to be caused by a mutation of the CF-gene coding for the cystic fibrosis transmembrane regulator protein (CFTR). CFTR represents a regulating transport protein for ion channels and processes involving endo- and exocytosis. Despite the identification of the genetic mutation knowledge of the underlying cellular pathways is limited. In the present experiments the cholinergic system was investigated in the peripheral blood and in the lung of CF patients undergoing lung transplantation (n=7). Acetylcholine content in bronchi and lung parenchyma of CF was reduced by 70% compared to controls (tumor-free tissue obtained from patients with lung tumor; n=13). In contrast, ChAT activity was elevated to some extent (p>0.05) in CF, and esterase activity did not differ from control. Acetylcholine content extracted from peripheral leucocytes (30 ml) was also reduced by 70% in CF (n=13) compared to healthy volunteers (n=9). Double labelling experiments with anti-CF antibodies and anti-ChAT antibodies showed a co-localization in peripheral lymphocytes, giving first evidence that CFTR may be linked with the intracellular storage/transport of non-neuronal acetylcholine. It is concluded that the non-neuronal cholinergic system is involved in the pathogenesis of CF. A reduced content of non-neuronal acetylcholine could contribute to the deleterious changes of epithelial ion and water movements in CF, because acetylcholine stimulates apical Cl(-) secretion, inhibits apical Na(+) and water absorption and therewith facilitates mucociliary clearance.

Inhalation solutions: which one are allowed to be mixed? Physico-chemical compatibility of drug solutions in nebulizers.

Therapy of chronic respiratory diseases often involves inhalation therapy with nebulizers. Patients often attempt to shorten the time consuming administration procedure by mixing drug solutions/suspensions for simultaneous inhalation. This article considers the issue of physico-chemical compatibility of admixtures of drug solutions/suspensions in nebulizers. A search of databases, prescribing information and primary literature was conducted to locate literature concerning the physico-chemical compatibility of inhalation solutions/suspensions. This was supplemented by telephone interviews. Admixtures of albuterol with ipratropium and/or cromolyn, of albuterol and budesonide, or tobramycin, or colistin are physico-chemically compatible. Physico-chemical compatibility has been demonstrated for admixtures of cromolyn with albuterol and/or ipratropium and for admixtures of cromolyn and budesonide. Admixtures of budesonide with ipratropium and/or fenoterol, and admixtures of budesonide and albuterol, or cromolyn are physico-chemically compatible. Both cromolyn and colistin are incompatible with benzalkonium chloride. Admixtures should be prepared from inhalation solutions/suspensions formulated without preservatives. Besides studies of the physico-chemical compatibility, the aerodynamic behaviour of physico-chemical mixtures needs to be studied before a final recommendation of simultaneous nebulization of compatible admixtures can be made.

Predicting hypoxia in cystic fibrosis patients during exposure to high altitudes.

BACKGROUND: For patients with cystic fibrosis (CF)-related partial respiratory insufficiency and reduced arterial oxygen tension at ground level, the mild hypobaric environment on commercial jet aircraft poses the risk of severe hypoxemia. Thus, physicians should be able to estimate the extent of in-flight hypoxia. OBJECTIVES: To derive tools for estimating the expected drop in arterial oxygen partial pressure (paO(2)) and oxygen saturation (saO(2)) in young adult CF patients with mild to moderate airway obstruction during exposure to the hypobaric conditions aboard commercial aircraft and to test the predictive power of a hypobaric chamber simulation. METHODS: Blood gases of 12 CF patients were measured at ground level, at two altitudes in a hypobaric chamber (2000 and 3000 m) and during two 3.5-h flights at cabin altitudes of 1855 m and 1700 m. The altitude dependence of paO(2) and saO(2) in the chamber and during the flights was calculated and results were used to derive estimation equations for in-flight values. RESULTS: In the chamber, saO(2) decreased by 0.33% per 100 m vertical ascent, and this rate increased significantly at altitudes >2000 m. Predicted saO(2) differed from in-flight value by <5%, and agreement between in-flight saO(2) decrease rate and chamber data was good. paO(2) decreased at a rate of 0.99 mm Hg/100 m in the chamber and by 1.33 mm Hg/100 m during flights. None of the subjects showed any clinical symptoms during the flights and the chamber simulation. CONCLUSION: During our worst-case scenario, i.e. the hypobaric chamber simulation at 3000 m, 90% of patients tolerated paO(2) values below the commonly recommended threshold of 50 mm Hg, probably due to adaptation to chronic hypoxemia and lung function impairment. We propose the following equations for an estimation of the expected extent of in-flight hypoxemia in CF patients with mild to moderate airway obstruction and a flight duration of up to 3.5 h: -paO2[Alt]=paO2[ground] -1.33 x Alt[mm Hg], and -saO2[Alt]=saO2[ground] -0.33 x Alt [%], with Alt=altitude in 100 m. In addition to the overall clinical situation of a patient, these equations will serve as a practical supportive tool for the assessment of the fitness to fly in the primary care setting.

Respiratory function and blood gas variables in cystic fibrosis patients during reduced environmental pressure.

Patients with cystic fibrosis (CF) suffer from hypoxaemia even under normobaric conditions and the reduction of inspiratory PO2 (O2 partial pressure) during air travel corresponding to an altitude of 1,800-2,450 m might be a problem for these patients. Ten CF patients and 27 healthy control subjects were investigated in a chamber where the ambient pressure was reduced to that found at 2,000 and 3,000 m. The respiratory function was reduced in the CF patients with a vital capacity of 3.1 (0.3) l [vs 4.9 (0.2) l in controls; mean (SEM)] and a forced expiratory 1-s volume of 2.1 (0.3) l [vs 4.3 (0.20 l in controls], unrelated to the reduction in ambient pressure. Mean arterial PO2 decreased from 75 (4) mmHg [85 (1) mmHg in controls, P<0.01] at sea level to 58 (3) mmHg at 580 mmHg and to 46 (1) mmHg [58 (1) mmHg and 49 (2) mmHg in controls, n.s.] at 513 mmHg ambient pressure. These results indicate that during air travel with a cabin pressure that corresponds to an altitude of 2,500 m, the arterial PO2 of CF patients is likely to remain above the accepted critical value of 50 mmHg. However, a further reduction of the pressure to that found at 3,000 m altitude may lead to severe hypoxia in patients with moderate airway obstruction.

The development of childhood asthma: lessons from the German Multicentre Allergy Study (MAS).

Epidemiological surveys have indicated that there has been a notable increase in the prevalence of both asthma and other allergic symptoms in children and young adults. Since it seems unlikely that genetic factors would contribute to the rising trend, environmental factors might play a major part in the development of childhood asthma. In a prospective birth-cohort study, we assessed the relevance of different exposures such as mite and cat allergen exposure, environmental tobacco smoke (ETS) exposure, early infectious diseases and vaccinations for the development of childhood asthma up to the age of 10 years. Data up to 7 years of age have been evaluated. Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 7 years were available for 939 children (72%). Assessments included repeated measurements of specific IgE to food and inhalant allergens, measurement of indoor allergen exposure at 6 months, 18 months and 3 years of age and yearly interviews by a paediatrician. At age 7 years, pulmonary function was tested and bronchial responsiveness was determined in 645 children. At age 7, the prevalence of wheezing in the past 12 months was 10% (94 out of 938), and 6.1% (57 out of 939) parents reported a doctor's diagnosis of asthma in their children. Sensitisation to indoor allergens was associated with asthma, wheeze and increased bronchial responsiveness. However, no relationship between early indoor allergen exposure and the prevalence of asthma, wheeze and bronchial responsiveness was seen. During the first 3 years of life, intra-uterine tobacco and consistent ETS exposure have an adjuvant effect on allergic sensitisation that is transient and restricted to children with a genetic predisposition for allergy. Children sensitised to any allergen early in life and sensitised to inhalant allergens by the age of 7 years were at a significantly increased risk of being asthmatic at this age (odds ratio (OR) = 10.12; 95% confidence interval (CI) = 3.81-26.88). Children with repeated episodes (> or =2) of runny nose before the age of 1 year were less likely to develop asthma by the age of 7 years (OR = 0.52; 95% CI = 0.29-0.92). Our data do not support the hypothesis that exposure to environmental allergens directly causes asthma in childhood but that induction of specific IgE responses and the development of childhood asthma are determined by independent factors. Indoor allergen avoidance is recommended as first line treatment in secondary and tertiary prevention; however, conclusions should be drawn with caution about the possible effect of primary preventative measures. Since allergic asthma seems to be a Th2-disease, immunomodulating factors such as early childhood infections, LPS-exposure or other factors influencing gene-environment interaction and individual susceptibility seem to be relevant for the development of childhood asthma.