The relationship between respiratory system impedance and lung function in asthmatics: A prospective observational study

INTRODUCTION

The aim was to elucidate the relationship between the annual changes in respiratory system impedance, measured by FOT, and lung function tests in patients with asthma.

METHODS

Between March 2011 and March 2012, asthma outpatients who attended Kobe City Medical Center West Hospital were recruited. Lung function tests, FOT were conducted every 6 months until March 2016. The relationships between annual parameter changes were evaluated.

RESULTS AND CONCLUSION

Sixty-four patients were completed this study. The median follow-up period was 55 months. At enrollment, although resistance showed no relationship with forced expiratory volume in one second (%FEV₁), the reactance was moderately correlated with X5 (r=0.524, r²=0.275, <0.001), Fres (r=-0.498, r²=0.248, <0.001) and ALX (r=-0.416, r²=0.173, p=<0.001). By contrast, the annual resistance change at 5Hz (R5) was highly and significantly associated with%FEV₁ change (r=-0.564, r²=0.318, p<0.001). Longitudinal changes in airway resistance and reactance measured by FOT might be useful for the assessment of lung function in patients with asthma.

Three-dimensional imaging forced oscillation technique to assess position-dependent airway obstruction in relapsing polychondritis: A case report

Relapsing polychondritis (RP) is characterized by recurrent systemic inflammation of the cartilages and is accompanied by central airway collapse. We report a case wherein three-dimensional imaging of respiratory system resistance (Rrs) and respiratory system reactance (Xrs) by using MostGraph (CHEST M.I., Tokyo, Japan), a forced oscillation system, revealed that Rrs and Xrs in the inspiratory and expiratory phases correlated with proximal airway collapse. The degree of difference in Rrs and Xrs between the supine and sitting positions reflected airway collapse more closely than did the pulmonary function test. MostGraph could be a useful tool for assessing airway collapse in RP.

Endoplasmic reticulum stress influences bronchial asthma pathogenesis by modulating nuclear factor κB activation

BACKGROUND

Despite many studies on endoplasmic reticulum (ER) stress in patients with various inflammatory diseases, there is scarce information on ER stress in patients with bronchial asthma.

OBJECTIVE

In this study we aimed to elucidate the role of ER stress in the pathogenesis of bronchial asthma.

METHODS

Using mice sensitized with ovalbumin (OVA) and LPS and challenged with OVA (OVA(LPS)-OVA mice), as well as mice sensitized and challenged with OVA (OVA-OVA mice), we investigated whether ER stress is involved in the pathogenesis of bronchial asthma. Moreover, we also determined the levels of ER stress markers in blood and bronchoalveolar lavage fluid from asthmatic patients.

RESULTS

The OVA(LPS)-OVA mice showed that the expression of ER stress markers and the protein levels of unfolded protein response-related markers in lung tissue were significantly increased after OVA challenge. Moreover, we found that ER stress markers in PBMCs and bronchoalveolar lavage fluid from human asthmatic patients were dramatically increased compared with those from healthy control subjects. In OVA(LPS)-OVA mice 4-phenylbutyric acid (4-PBA), a chemical chaperone, significantly reduced the increases in ER stress, nuclear translocation of nuclear factor κB, inflammatory cytokine levels, dendritic cell infiltration, Toll-like receptor 4 expression, airway inflammation, and bronchial hyperresponsiveness, whereas it further enhanced the increase in IL-10 levels. Additionally, the established asthmatic features of OVA-OVA mice were substantially attenuated by 4-PBA administered after completion of OVA challenge.

CONCLUSION

These results indicate that ER stress might be implicated in the pathogenesis of bronchial asthma at least in part through modulation of nuclear factor κB activation.