Summary Background Hydrogen was proven to have anti-oxidative and anti-inflammation effects to various diseases. Aim We wish to investigate the acute effects of inhaled hydrogen on airway inflammation in patients with asthma and chronic obstructive pulmonary disease (COPD). Design Prospective study. Methods 2.4% hydrogen containing steam mixed gas (XEN) was inhaled once for 45 minutes in 10 patients with asthma and 10 patients with COPD. The levels of granulocyte-macrophage colony stimulating factor (GM-CSF), interferon-γ (IFNγ), interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), et al. in peripheral blood and exhaled breath condensate (EBC) before and after “XEN” inhalation were measured. Results 45 minutes “XEN” inhalation once decreased monocyte chemotactic protein 1 (MCP1) level in both COPD (564.70 to 451.51pg/mL, P = 0.019) and asthma (386.39 to 332.76 pg/mL, P = 0.033) group, while decreased IL-8 level only in asthma group (5.25 to 4.49pg/mL, P = 0.023). The level of EBC soluble cluster of differentiation-40 ligand (sCD40L) in COPD group increased after inhalation (1.07 to 1.16pg/mL, P = 0.031), while IL-4 and IL-6 levels in EBC were significantly lower after inhalation in the COPD (0.80 to 0.64pg/mL, P = 0.025) and asthma (0.06 to 0.05pg/mL, P = 0.007) group respectively. Conclusions A single inhalation of hydrogen for 45 minitues attenuated inflammatory status in airways in patients with asthma and COPD.

Purpose: 68-gallium (Ga-68) ethylenediaminetetraacetic acid (EDTA) aerosols and Galligas were compared in evaluation of inhaled-particle deposition and clearance in volunteers with or without obstructive pulmonary diseases. Methods: Nonsmoking healthy volunteers, healthy smokers, asthma patients and patients with chronic obstructive pulmonary disease (COPD) were recruited to undergo the dynamic lung ventilation positron emission tomography/computerized tomography (PET/CT) scans within two consecutive days. The inhaled particles were Ga-68labelled carbon nanoparticles (Galligas, 30-60 nm in size) and Ga-68-labelled EDTA aerosols (1-2 μm in size), respectively. The volunteers' lung function parameters were measured for comparison. Results: Central deposition and inhomogeneity of both tracers were negatively correlated with lung function parameters, including the ratio of forced expiratory volume at 1 second to forced vital capacity (FEV 1 /FVC). The central or hilum deposition of Galligas, but not 68-gallium (Ga-68) EDTA, was negatively correlated with the maximal expiratory flow at 25%, 50% and 75% of the forced vital capacity. Compared with Galligas, Ga-68 EDTA aerosols were more concentrated in the central region in all groups except for the healthy nonsmokers. Ventilation inhomogeneity was more evident when using Ga-68 EDTA aerosols, especially in patients with COPD and asthma patients. In the healthy smokers, the central region accumulated more Ga-68 EDTA at 30 minutes after inhalation than immediately after inhalation. Ga-68 EDTA cleared faster in lungs than Galligas.