Airway and systemic inflammatory responses to ultrafine carbon black particles and ozone in older healthy subjects.

Increased adverse health effects in older subjects due to exposure to ambient air pollutants may be related to the inflammatory response induced by these contaminants. The aim of this study was to assess airway and systemic inflammatory responses in older healthy subjects to a controlled experimental exposure with spark-generated elemental carbon black ultrafine particles (cbUFPs) and ozone (O3). Twenty healthy subjects, age 52-75 years, were exposed on three occasions separated by at least 8 weeks. The exposures to filtered air (FA), to cbUFP (50 µg/m3), or to cbUFP in combination with 250 ppb ozone (cbUFP + O3) for 3 h with intermittent exercise were performed double blind, and in random order. Sputum and blood samples were collected 3.5 h after each exposure. Exposure to cbUFP + O3 significantly increased plasma club cell protein 16 (CC16), the number of sputum cells, the number and percent of sputum neutrophils, and sputum interleukin 6 and matrix metalloproteinase 9. Exposure to cbUFP alone exerted no marked effect, except for an elevation in sputum neutrophils in a subgroup of 13 subjects that displayed less than 65% sputum neutrophils after FA exposure. None of the inflammatory markers was correlated with age, and serum cardiovascular risk markers were not markedly affected by cbUFP or cbUFP + O3. Exposure to cbUFP+O3 induced a significant airway and systemic inflammatory response in older healthy volunteer subjects. The effects induced by cbUFP alone suggest that the inflammation was predominantly mediated by O3, although one cannot rule out that the interaction of cbUFP and O3 played a role.

Airway hyper-responsiveness in lipopolysaccharide-challenged common marmosets (Callithrix jacchus).

Animal models with a high predictive value for human trials are needed to develop novel human-specific therapeutics for respiratory diseases. The aim of the present study was to examine lung-function parameters in marmoset monkeys (Callithrix jacchus) that can be used to detect pharmacologically or provocation-induced AHR (airway hyper-responsiveness). Therefore a custom-made lung-function device that allows application of defined aerosol doses during measurement was developed. It was hypothesized that LPS (lipopolysaccharide)-challenged marmosets show AHR compared with non-challenged healthy subjects. Invasive plethysmography was performed in 12 anaesthetized orotracheally intubated and spontaneously breathing marmosets. Pulmonary data of R(L) (lung resistance), C(dyn) (dynamic compliance), EF50 (mid-expiratory flow), P(oes) (oesophageal pressure), MV (minute volume), respiratory frequency (f) and V(T) (tidal volume) were collected. Measurements were conducted under baseline conditions and under MCh (methacholine)-induced bronchoconstriction. The measurement was repeated with the same group of animals after induction of an acute lung inflammation by intratracheal application of LPS. PDs (provocative doses) of MCh to achieve a certain increase in RL were significantly lower after LPS administration. AHR was demonstrated in the LPS treated compared with the naïve animals. The recorded lung-function data provide ground for pre-clinical efficacy and safety testing of anti-inflammatory substances in the common marmoset, a new translational NHP (non-human primate) model for LPS-induced lung inflammation.

Effects of ultrafine particles on the allergic inflammation in the lung of asthmatics: results of a double-blinded randomized cross-over clinical pilot study.

BACKGROUND: Epidemiological and experimental studies suggest that exposure to ultrafine particles (UFP) might aggravate the allergic inflammation of the lung in asthmatics. METHODS: We exposed 12 allergic asthmatics in two subgroups in a double-blinded randomized cross-over design, first to freshly generated ultrafine carbon particles (64 µg/m³; 6.1 ± 0.4 × 105 particles/cm³ for 2 h) and then to filtered air or vice versa with a 28-day recovery period in-between. Eighteen hours after each exposure, grass pollen was instilled into a lung lobe via bronchoscopy. Another 24 hours later, inflammatory cells were collected by means of bronchoalveolar lavage (BAL). ( TRIAL REGISTRATION: NCT00527462) RESULTS: For the entire study group, inhalation of UFP by itself had no significant effect on the allergen induced inflammatory response measured with total cell count as compared to exposure with filtered air (p = 0.188). However, the subgroup of subjects, which inhaled UFP during the first exposure, exhibited a significant increase in total BAL cells (p = 0.021), eosinophils (p = 0.031) and monocytes (p = 0.013) after filtered air exposure and subsequent allergen challenge 28 days later. Additionally, the potential of BAL cells to generate oxidant radicals was significantly elevated at that time point. The subgroup that was exposed first to filtered air and 28 days later to UFP did not reveal differences between sessions. CONCLUSIONS: Our data demonstrate that pre-allergen exposure to UFP had no acute effect on the allergic inflammation. However, the subgroup analysis lead to the speculation that inhaled UFP particles might have a long-term effect on the inflammatory course in asthmatic patients. This should be reconfirmed in further studies with an appropriate study design and sufficient number of subjects.

A pilot study on the refinement of acute inhalation toxicity studies: the isolated perfused rat lung as a screening tool for surface-active substances.

New surface-active agents in waterproofing sprays are frequently tested for acute inhalation toxicity in vivo according to OECD Test Guideline 403. In order to refine and reduce the number of acute inhalation tests performed, we propose a screening test that uses isolated lungs. The test consists of the exposure of isolated, ventilated and perfused rat lungs, to aerosolised formulations of waterproofing agents (mass median aerodynamic diameter = 1µm), and on-line monitoring of respiratory parameters and gross pathology analysis. A pilot evaluation of the isolated perfused rat lung model for use in a screening test was carried out by blind testing 12 surface-active substances. The results obtained compared well with data available from in vivo acute inhalation studies. Substances that triggered harmful effects, such as impaired lung compliance and atelectasis of the isolated perfused lung, were also found to cause changes in respiratory parameters, some of which would be severe enough to lead to death in in vivo tests with rats. The changes in respiratory parameters suggest that the mode-of-action is associated with impairment of the surfactant layer. Therefore, pre-testing in the isolated perfused rat lung allows the identification of surface-active substances with the potential for causing acute inhalation toxicity.

Particle deposition in the lung of the Göttingen minipig.

We report on particle deposition in the tracheobronchial and pulmonary regions of the respiratory tract of the minipig and its dependence on particle size. Four animals breathing spontaneously via the nose were exposed for 1 h to known concentrations of three different polydisperse dry aerosols composed of bovine serum albumin (BSA) and an oxide of a rare earth element: Y2O3, Sm2O3, and Er2O3. The mass size distributions of the rare earth elements of the three test aerosols have mass median aerodynamic diameters of 0.9, 2.5, and, 4.3 microm, and geometric standard deviations of sigma(g) = 2.0, 1.8, and, 1.7. The extrathoracic, tracheobronchial, and pulmonary regions of the respiratory tract were dissected, separately lyophilized, and chemically digested by microwave-assisted high pressure digestion. The tracer element in each compartment was determined by inductively coupled plasma mass spectrometry. A mass balance equation relating the tracer mass found in the lung compartments to the tracer mass inhaled was solved by linear regression to obtain the deposition fraction as function of particle sizes for the tracheobronchial and the pulmonary lung region. Estimated values for the respiratory minute volume were used in this context. For coarse particles > 6 microm, the deposition fraction is < 5% for both compartments. The deposition fraction for particles with aerodynamic diameter of approximately 3 microm is 21% in the tracheobronchial airways and 40% in the pulmonary airways.

Characterization of exhaled particles from the human lungs in airway obstruction.

BACKGROUND: Human breath contains small particles that might be useful for the noninvasive diagnosis of lung disease. In this study, the impact of airway obstruction on particle emission was investigated. METHODS: Particle number flux and particle size distribution were measured for healthy nonsmokers (n=16), healthy smokers (n=13), patients with chronic obstructive pulmonary disease (n=28, GOLD stage I-IV), and patients with asthma before and after methacholine challenge (n=10). The measurements were carried out using a condensation nucleus counter (TSI 3760) and a laser spectrometer (PMT LASAIR II-110). RESULTS: Particle number per breath showed high intrasubject reproducibility. However, there was a large intersubject variability in the number of emitted particles on the order of two magnitudes, with no influence of airway obstruction on emission level. Methacholine-induced airway obstruction, in subjects with allergic asthma, did not change the number of exhaled particles, when compared with prechallenge values. For the droplet size distribution averaged per breath, there was no difference between healthy subjects and subjects with airway obstruction. CONCLUSIONS: Airway obstruction does not change the number flux or size distribution of particles in exhaled breath. The high intersubject variability of particle emission supports the concept of online determination of aerosol properties (primarily number flux, during exhaled breath) during breath condensate sampling to properly normalize the results of biochemical analysis. As high dilution and variable dilution are the main challenges of biomarker assessment in exhaled breath condensate, this normalization procedure would significantly add to the value of the technique.

Breath profiles by electronic nose correlate with systemic markers but not ozone response.

BACKGROUND: The evaluation of exhaled breath profiles by electronic nose (eNose) is considered as a promising non-invasive diagnostic tool, and the discrimination of breathprints between patients with COPD and asthma has been reported. The aim of this study was to assess, whether exhaled breath profile analysis can detect the inflammatory airway response induced by ozone inhalation. METHODS: In a randomized double-blind, cross-over study 14 healthy ozone-responsive subjects were exposed to 250 ppb ozone and filtered room air for 3h with intermittent exercise. Blood biomarkers, exhaled NO, exhaled CO, and breathprints (Cyranose 320(®)) were assessed prior and at 3 time points up to 24h post exposure. Induced sputum was collected at baseline and 3h post exposure. Multivariate analysis of eNose data was performed using transformed and normalized datasets. RESULTS: Significantly increased numbers of sputum and blood neutrophils were observed after ozone, whereas the eNose signals showed no differences between exposures and no correlation with neutrophilic airway inflammation. However, independent of ozone exposure, sensor data correlated with serum SP-D levels and to a smaller extent with blood neutrophil numbers. CONCLUSIONS: Exhaled breath profiles as measured by the Cyranose 320(®) did not reflect airway responses to ozone. This suggests that exhaled volatiles did not change with ozone challenges or that the changes were below the detection limits. Conversely, the correlation of eNose signals with blood neutrophils and serum SP-D, i.e. markers of systemic inflammation and lung permeability, suggested that the Cyranose 320(®) can detect volatile organic compounds of systemic origin.

Characterization of exhaled particles from the healthy human lung--a systematic analysis in relation to pulmonary function variables.

BACKGROUND: Noninvasive monitoring of airway inflammation is important for diagnosis and treatment intervention of lung disease. Mediators of interest are often nonvolatile molecules that are exhaled as aerosols and captured by breath condensation. Because analysis of exhaled breath condensate has been troublesome in the past, partly due to poor standardization and unknown dilution, we investigated in detail the influence of respiratory variables on exhaled particle number and size distribution during tidal breathing in healthy volunteers. METHODS: Particle number was detected by a condensation nuclei counter, and size distribution was determined by a laser spectrometer online with high time resolution while subjects underwent a defined protocol of normal and deep tidal breathing. Intra- and intersubject variability of particle emission was analyzed and physical properties of exhaled aerosols were correlated to pulmonary function variables obtained by body-plethysmography. RESULTS: The particle size distribution was in the submicron range and stable during tidal breathing. Increasing tidal volumes dominantly influenced particle number emission while flow rates had only little effect. Reproducibility within subjects was high, but there was a large variation of particle emission between subjects. The ratio of functional residual capacity to total lung capacity was found to correlate with exhaled particle numbers. This indicates that particle generation is caused by reopening of terminal airways and is dependent on functional residual capacity. CONCLUSION: We conclude that online determination of exhaled aerosols from the human lungs is a prerequisite to standardize the assessment of nonvolatile mediators by normalization to the aerosol emission rate.