Hee-Kyoo Kim

Titanium Dioxide Exposure Induces Acute Eosinophilic Lung Inflammation in Rabbits

Titanium dioxide (TiO2) is increasingly widely used in industrial, commercial and home products. TiO2 aggravates respiratory symptoms by induction of pulmonary inflammation although the mechanisms have not been well investigated. We aimed to investigate lung inflammation in rabbits after intratracheal instillation of P25 TiO2. One ml of 10, 50 and 250 µg of P25 TiO2 was instilled into one of the lungs of rabbits, chest computed-tomography was performed, and bronchoalveolar lavage (BAL) fluid was collected before, at 1 and 24 h after P25 TiO2 exposure. Changes in inflammatory cells in the BAL fluids were measured. Lung pathological assay was also carried out at 24 h after P25 TiO2 exposure. Ground glass opacities were noted in both lungs 1 h after P25 TiO2 and saline (control) instillation. Although the control lung showed complete resolution at 24 h, the lung exposed to P25 TiO2 showed persistent ground glass opacities at 24 h. The eosinophil counts in BAL fluid were significantly increased after P25 TiO2 exposure. P25 TiO2 induced a dose dependent increase of eosinophils in BAL fluid but no significant differences in neutrophil and lymphocyte cell counts were detected. The present findings suggest that P25 TiO2 induces lung inflammation in rabbits which is associated with eosinophilic inflammation.

Changes in skin reactivity and associated factors in patients sensitized to house dust mites after 1 year of allergen-specific immunotherapy

Background Allergen-specific immunotherapy (SIT) can significantly improve symptoms and reduce the need for symptomatic medication. Objective The aim of this study was to investigate changes in skin reactivity to house dust mites (HDMs) as an immunologic response and associated factors after 1 year of immunotherapy. Methods A total of 80 patients with allergic airway diseases who received subcutaneous SIT with HDMs from 2009 to 2014 were evaluated. The investigated parameters were basic demographic characteristics, skin reactivity and specific IgE for HDM, serum total IgE level, blood eosinophil counts, and medication score. Results The mean levels of skin reactivity to HDMs, blood eosinophil counts, and medication scores after 1 year were significantly reduced from baseline. In univariate comparison of the changes in skin reactivity to HDMs, age ≤30 years, HDMs only as target of immunotherapy, and high initial skin reactivity (≥2) to HDMs were significantly associated with the reduction in skin test reactivity. In multivariate analysis, high initial skin reactivity and HDMs only as target allergens were significantly associated with changes in skin reactivity to HDMs. In the receiver operating characteristic curve of the initial mean skin reactivity to HDMs for more than 50% reduction, the optimal cutoff value was 2.14. Conclusion This study showed significant reductions in allergen skin reactivity to HDMs after 1 year of immunotherapy in patients sensitized to HDMs. The extent of initial allergen skin reactivity and only HDMs as target allergen were important predictive factors for changes in skin reactivity.

In vivo real-time imaging of airway dynamics during bronchial challenge test.

Asthmatic patients exhibit airway hyper‐responsiveness, which induces bronchoconstriction and results in a ventilation defect. The bronchial challenge test using methacholine is a useful way to measure airway hyper‐responsiveness with airway constriction. Anatomical optical coherence tomography has been used to image airway hyper‐responsiveness of medium sized bronchus with the aid of an endoscopic probe. Recently, a thoracic window was reported that allows direct visualization of terminal airway such as alveolus. A multi‐scale integrated airway dynamics was assessed in this study. We imaged in vivo changes in the right intermedius bronchus and alveolar structure during the bronchial challenge test using two optical coherence tomography systems and correlated the changes with airway resistance.

Environmental and occupational respiratory diseases – 1059. Lung exposure to TiO2 induces eosinophilic airway inflammation in the rabbits

Background Titanium dioxide (TiO2) nanoparticels (NPs), one of the most abundantly utilized nanomaterials, was widely used in industry, cosmetics, and biomedicine. There have been reported that TiO2 NPs aggravates respiratory symptoms by induce pulmonary inflammation. However, the mechanisms of these effects have not been extensively studied yet. We aimed to investigate inflammation in rabbit lung following an intratracheal instillation.