Jaring S. van der Zee

Inhalation of particulate matter, as part of air pollution, is associated with increased morbidity and mortality. Nanoparticles (< 100 nm) are likely candidates for triggering inflammatory responses and activation of coagulation pathways because of their ability to enter lung cells and pass bronchial mucosa. We tested the hypothesis that bronchial segmental instillation of carbon nanoparticles causes inflammation and activation of coagulation pathways in healthy humans in vivo. This was an investigator-initiated, randomized controlled, dose-escalation study in 26 healthy males. Participants received saline (control) in one lung segment and saline (placebo) or carbon nanoparticles 10 μg, 50 μg, or 100 μg in the contra-lateral lung. Six hours later, blood and bronchoalveolar lavage fluid (BALF) was collected for inflammation and coagulation parameters. There was a significant dose-dependent increase in blood neutrophils (p = 0.046) after challenge with carbon nanoparticles. The individual top-dose of 100 μg showed a significant (p = 0.05) increase in terms of percentage neutrophils in blood as compared to placebo. This study shows a dose-dependent effect of bronchial segmental challenge with carbon nanoparticles on circulating neutrophils of healthy volunteers. This suggests that nanoparticles in the respiratory tract induce systemic inflammation. Dutch Trial Register no. 2976. 11 July 2011. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2976

Clinical studies investigating medicinal products need to comply with laws concerning good clinical practice (GCP) and good manufacturing practice (GMP) to guarantee the quality and safety of the product, to protect the health of the participating individual and to assure proper performance of the study. However, there are no specific regulations or guidelines for non-Medicinal Investigational Products (non-MIPs) such as allergens, enriched food supplements, and air pollution components. As a consequence, investigators will avoid clinical research and prefer preclinical models or in vitro testing for e.g. toxicology studies. 1) briefly review the current guidelines and regulations for Investigational Medicinal Products; 2) present a standardised approach to ensure the quality and safety of non-MIPs in human in vivo research; and 3) discuss some lessons we have learned. We propose a practical line of approach to compose a clarifying product dossier (PD), comprising the description of the production process, the analysis of the raw and final product, toxicological studies, and a thorough risk-benefit-analysis. This is illustrated by an example from a human in vivo research model to study exposure to air pollutants, by challenging volunteers with a suspension of carbon nanoparticles (the component of ink cartridges for laser printers). With this novel risk-based approach, the members of competent authorities are provided with standardised information on the quality of the product in relation to the safety of the participants, and the scientific goal of the study.

Tuberculosis (TB) is an important cause of morbidity and mortality worldwide. Toll-like-receptors (TLRs) are important for the recognition of the causative agent Mycobacterium tuberculosis. Negative regulation of TLRs is necessary to control deleterious inflammatory damage, but could provide a means of immune evasion by M. tuberculosis as well. To obtain insight in the extent of expression of inhibitory regulators of immunity in patients with active TB, peripheral-blood-mononuclear-cells (PBMCs) and plasma were obtained from 54 TB patients and 29 healthy blood donors from Chittagong, Bangladesh. Bilateral alveolar macrophages were obtained from an infected versus a contralateral normal lung segment of 9 patients. Statistical analyses were performed using Mann–Whitney U and Wilcoxon matched pairs testing. Correlations were calculated using the Spearman rho test. PBMCs harvested from TB patients demonstrated increased mRNA expression of IL-1-receptor-associated-kinase-M, suppressor-of-cytokine-signalling-3 and Toll-interacting-protein. Flow cytometry revealed enhanced expression of IL-1-receptor-like-1 (ST2) on lymphocytes. Plasma soluble ST2 was elevated in patients with TB and correlated with established TB biomarkers, most strongly with soluble interleukin-2 receptor subunit α and interleukin-8. Alveolar macrophage mRNA expression of negative TLR regulators did not differ between the infected and contralateral lung side. These results show enhanced expression of distinct negative regulators of innate immunity in PBMCs of patients with TB and identify plasma soluble ST2 as a potential novel biomarker for TB disease activity.

Background: House dust contains mite allergens as well as bacterial products such as lipopolysaccharide (LPS). Asthma exacerbations are associated with the level of exposure to allergens and LPS. LPS can potentiate allergen effects in steroid‐naïve patients. Long‐acting β2‐agonists (LABA) were shown to inhibit LPS‐induced bronchial inflammation in healthy volunteers. The aim of this study was to assess the effect of LPS on the allergen‐induced eosinophilic inflammation [primary endpoints: eosinophil counts and eosinophil cationic protein (ECP)] induced by bronchial instillation of house dust mite (HDM) in patients with asthma on maintenance treatment with inhaled corticosteroids (ICS).Methods: Thirty‐two nonsmoking asthmatics with HDM allergy were treated with run‐in medication (fluticasone propionate 100 μg bid) during 2 weeks before the study day. All patients underwent bronchial challenge with HDM, and half of them were randomized to receive additional LPS. Both groups were randomized to receive pretreatment with a single inhalation of 100 μg salmeterol 30 min before bronchial segmental challenge. Six hours later, bronchoalveolar lavage (BAL) was collected for leukocyte cell count, differentials, and cellular activation markers.Results: Challenge with HDM/LPS induced a significant increase in eosinophil cationic protein (P = 0.036) and a trend toward an increase in BALF eosinophils as compared to HDM challenge.Conclusion: Lipopolysaccharide promotes eosinophilic airway inflammation in patients with asthma despite being on maintenance treatment with ICS.

Protease-activated receptor-2 (PAR2) is abundantly expressed in the pulmonary compartment. House dust mite (HDM) is a common cause of allergic asthma and contains multiple PAR2 agonistic proteases. The aim of this study was to determine the role of PAR2 in HDM-induced allergic lung inflammation. For this, the extent of allergic lung inflammation was studied in wild type (Wt) and PAR2 knockout (KO) mice after repeated airway exposure to HDM. HDM exposure of Wt mice resulted in a profound influx of eosinophils in bronchoalveolar lavage fluid (BALF) and accumulation of eosinophils in lung tissue, which both were strongly reduced in PAR2 KO mice. PAR2 KO mice demonstrated attenuated lung pathology and protein leak in the bronchoalveolar space, accompanied by lower BALF levels of the anaphylatoxins C3a and C5a. This study reveals, for the first time, an important role for PAR2 in allergic lung inflammation induced by the clinically relevant allergens contained in HDM.

Background Patients with allergic asthma have exacerbations which are frequently caused by rhinovirus infection. The antiviral tryptophan-catabolising enzyme indoleamine 2,3-dioxygenase (IDO) is induced by interferon-γ and suppressed by Th2 mediators interleukin (IL)-4 and IL-13. We hypothesised that local IDO activity after viral airway infection is lower in patients with allergic asthma than in healthy controls. Objective To determine whether IDO activity differs between patients with allergic asthma and healthy individuals before and after rhinovirus infection. Methods Healthy individuals and patients with allergic asthma were experimentally infected with low-dose (10 TCID₅₀) rhinovirus 16. Blood, bronchoalveolar lavage fluid and exhaled breath condensate (for mass spectrometry by UPLC-MS/MS) were obtained before and after rhinovirus challenge. Results IDO activity was not induced by rhinovirus infection in either group, despite increases in cold scores. However, baseline pulmonary IDO activity was lower in patients with allergic asthma than in healthy individuals. In contrast, systemic tryptophan and its catabolites were markedly higher in patients with allergic asthma. Moreover, systemic quinolinic acid and tryptophan were associated with eosinophil cationic protein (r=0.43 and r=0.78, respectively) and eosinophils (r=0.38 and r=0.58, respectively) in bronchoalveolar lavage fluid and peak asthma symptom scores after rhinovirus challenge (r=0.53 and r=0.64, respectively). Conclusions Rhinovirus infection by itself induces no IDO activity, but the reduced pulmonary IDO activity in patients with allergic asthma at baseline may underlie a reduced control of viral infections. Notably, the enhanced systemic catabolism of tryptophan in patients with allergic asthma was strongly related to the outcome of rhinovirus challenge in asthma and may serve as a prognostic factor.

The complex biology of asthma compels the use of more relevant human allergens, such as house dust mite (HDM), to improve the translation of animal models into human asthma. LPS exposure is associated with aggravations of asthma, but the mechanisms remain unclear. Here, we studied the effects of increasing LPS doses on HDM-evoked allergic lung inflammation. To this end, mice were intranasally sensitized and challenged with HDM with or without increasing doses of LPS (0.001–10 μg). LPS dose-dependently inhibited HDM-induced eosinophil recruitment into the lungs and mucus production in the airways. LPS attenuated the production of Th2 cytokines (IL-4, IL-5, IL-10, and IL-13) in HDM-challenged lungs, while enhancing the HDM-induced release of IL-17, IL-33, IFN-γ, and TNF-α. The shift toward a Th1 inflammatory response was further illustrated by predominant neutrophilic lung inflammation after LPS administration at higher doses. LPS did not influence HDM-induced plasma IgE concentrations. Although LPS did not significantly affect the activation of coagulation or complement in HDM-challenged lungs, it reduced HDM-initiated endothelial cell activation. This study is the first to provide insights into the effects of LPS in an allergic lung inflammation model making use of a clinically relevant allergen without a systemic adjuvant, revealing that LPS dose-dependently inhibits HDM-induced pulmonary Th2 responses.

Intravenous administration of activated protein C (APC) inhibits coagulation and inflammation in the lungs of humans and animals. Investigations in rodents demonstrated that direct intrapulmonary delivery of APC also exerts anticoagulant and anti-inflammatory effects. The effect of intrabronchial administration of recombinant human (rh)APC on lipopolysaccharide (LPS)-induced haemostatic and inflammatory alterations in the bronchoalveolar space of humans was studied.Eight subjects received rhAPCviaintrabronchial instillation by bronchoscope, while in a contralateral subsegment subjects received saline; all subjects were challenged bilaterally with LPS in the same lung subsegments. Four additional subjects received rhAPC (75 μg), with saline as a control in the contralateral subsegment, while they were bilaterally “challenged” with saline. After 6 h a bronchoalveolar lavage was performed and coagulation and inflammatory parameters were measured.rhAPC enhanced LPS-induced coagulation activation in the bronchoalveolar space, when compared with the control side. In addition, rhAPC amplified LPS-induced pro-inflammatory responses, as indicated by higher concentrations of cytokines and chemokines. rhAPC alone did not have procoagulant or pro-inflammatory effects.Locally administered rhAPC has unexpected procoagulant and pro-inflammatory effects in LPS-challenged lung subsegments. These data argue against a role for intrapulmonary delivery of rhAPC as a treatment strategy for lung inflammatory disorders in humans.

Lipopolysaccharide (LPS) is ubiquitous in the environment. Inhalation of LPS has been implicated in the pathogenesis and/or severity of several lung diseases, including pneumonia, chronic obstructive pulmonary disease and asthma. Alveolar macrophages are the main resident leukocytes exposed to inhaled antigens. To obtain insight into which innate immune pathways become activated within human alveolar macrophages upon exposure to LPS in vivo, we conducted a study in eight healthy humans, in which we instilled sterile saline into a lung segment by bronchoscope, followed by instillation of LPS into the contralateral lung. Six hours later, a bilateral bronchoalveolar lavage was performed and whole-genome transcriptional profiling was done on purified alveolar macrophages, comparing cells exposed to saline or LPS from the same individuals. LPS induced differential expression of 2,932 genes in alveolar macrophages; 1,520 genes were upregulated, whereas 1,440 genes were downregulated. A total of 26 biological functions were overrepresented in LPS-exposed macrophages; 44 canonical pathways affected by LPS were identified, among which the genes associated with the role of pattern recognition receptors in recognition of bacteria and viruses represented the top pathway. Other pathways included cellular immune response, signaling by tumor necrosis factor (receptor) family members, cytokine signaling and glucocorticoid receptor signaling. These results reveal for the first time a large number of functional pathways influenced by the biologically relevant challenge provided by LPS administered into the airways. These data can assist in identifying novel targets for therapeutic intervention in pulmonary diseases associated with LPS exposure, including pneumonia, asthma and chronic obstructive pulmonary disease.