The Effect of Bronchoconstriction by Methacholine Inhalation in a Murine Model of Asthma.

INTRODUCTION: Bronchoconstriction was recently shown to cause airway remodeling and induce allergic airway inflammation in asthma. However, the mechanisms how mechanical stress via bronchoconstriction could induce airway inflammation and remodeling remain unclear. OBJECTIVE: We investigated the effect of bronchoconstriction induced by methacholine inhalation in a murine model of asthma. METHODS: BALB/c female mice were sensitized and challenged with ovalbumin (OVA), followed by treatment with methacholine by a nebulizer twice a day for 7 days. Twenty-four hours after the last methacholine treatment, the bronchoalveolar lavage fluid (BALF) and lung tissues were collected. The BALF was analyzed for total and differential cell counts and cytokine levels. The lung tissues were analyzed for goblet cell metaplasia, thickness of the smooth muscle, and lung fibrosis. The expression of cytokines in the lung was also examined. RESULTS: OVA sensitization and challenge induced infiltration of total cells, macrophages, and eosinophils in the BALF along with goblet cell metaplasia and increased airway smooth muscle hypertrophy. Seven days after the last OVA challenge, untreated mice achieved reduction in airway inflammation, while methacholine maintained the number of BALF total cells, macrophages, and eosinophils. The percentage of goblet cells and the thickness of airway smooth muscle were also maintained by methacholine. Moreover, the treatment of methacholine induced the expression of transforming growth factor (TGF)-ß in the lung. This result indicates that the production of TGF-ß is involved in induction of airway remodeling caused by bronchoconstriction with methacholine. CONCLUSIONS: Repeated bronchoconstriction caused by methacholine inhalation elicited allergic airway inflammation and airway remodeling.

Inhibition of Virus-Induced Cytokine Production from Airway Epithelial Cells by the Late Addition of Budesonide.

BACKGROUND: Viral infection is the main cause of asthma and COPD (chronic obstructive pulmonary disease) exacerbation and accumulate inflammatory cells to airway tissue. We have reported poly I:C, a mimic product of the virus and ligand of toll-like receptor 3 (TLR3), induced inflammatory chemokines from airway epithelial cells and found prior incubation with corticosteroids diminishes the effect of TLR3 activation. In clinical practice, mild asthma is recommended as-needed budesonide (BUD) when symptoms occur following a viral infection, etc. However, many questions still surround BUD's usefulness if taken after a virus has already infected airway tissue. OBJECTIVE: The aim of this study was to investigate the inhibitory effects of BUD on inflammatory cytokines induced by viral infection. Methods: Normal human bronchial epithelial (NHBE) cells were stimulated with poly I:C or infected with human rhinovirus-16 (HRV16) and BUD was added after the initial stimulation. Expression of both thymic stromal lymphopoietin (TSLP) and CCL26/eotaxin-3 was quantified by real-time RT-PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Knockdown study was performed. Results: Pre-or post-incubation with BUD inhibited both poly I:C- and HRV16-induced mRNAs and proteins of both thymic stromal lymphopoietin (TSLP) and CCL26 with significance. Knockdown of the glucocorticoid receptor diminished these effects of BUD. Under the same conditions of BUD's experiment, post-incubation with neither fluticasone propionate nor dexamethasone suppressed expression of both TSLP and CCL26, which induced by poly I:C. CONCLUSION: Post-addition of BUD inhibited the virus-induced TSLP and CCL26 from the airway epithelial cells. These results suggest that inhalation of BUD after viral infection has beneficial effects on asthma. CONCLUSION: Late addition of BUD may benefit among patient with viral infection and type 2 allergic airway disease such as asthma.

Exposure to intermittent hypoxia inhibits allergic airway inflammation in a murine model of asthma.

PURPOSE: Obesity increases the severity of asthma, and patients with severe asthma are often complicated with obstructive sleep apnea syndrome (OSAS), a concomitant disease of obesity. We investigated whether intermittent hypoxia (IH), which is a physiological feature of OSAS, modifies allergic airway inflammation in a murine model of asthma. METHODS: Balb/c mice were sensitized by ovalbumin (OVA) intraperitoneally twice (days 1 and 14) and challenged with intranasal OVA three times (days 21, 22, and 23). The mice were exposed to IH either from days 1 to 24 (long exposure) or only from days 21 to 24 (short exposure). The impact of IH exposure to allergic airway inflammation was investigated using these mice models by histologic, morphometric, and molecular techniques. Additionally, the airway responsiveness to acetylcholine was also assessed. RESULTS: OVA-sensitized and OVA-challenged mice exposed to room air (RA) showed increased total cell and eosinophil numbers in the BALF. The levels of interleukin (IL)-5 and IL-13 in the BALF also increased and goblet cell metaplasia was induced. In contrast, both long and short exposure to IH inhibited the increased total cell and eosinophil numbers. The levels of IL-5 and IL-13 in the BALF also decreased on exposure to IH. Moreover, the goblet cell hyperplasia and airway hyperresponsiveness were significantly reduced in mice exposed to IH compared to those exposed to RA. CONCLUSIONS: These results suggest that IH may not deteriorate the asthmatic condition in a murine model of asthma.

Anti-inflammatory and anti-melanogenic proanthocyanidin oligomers from peanut skin.

Peanut skin (Arachis hypogaea L., Fabaceae) is an abundant source for polyphenols, such as proanthocyanidin oligomers. To determine whether proanthocyanidin has beneficial effects on skin, we tested for inhibitory activity of proanthocyanidins isolated from peanut skin on inflammatory cytokine production and melanin synthesis in cultured cell lines. Administration of peanut skin extract (PSE, 200 µg/mL) decreased melanogenesis in cultured human melanoma HMV-II co-stimulated with phorbol-12-myristate-13-acetate. It also decreased production of inflammatory cytokines (PSE at 100 µg/mL), tumor necrosis factor-α and interleukin-6, in cultured human monocytic THP-1 cells in response to lipopolysaccharide. We isolated ten known proanthocyanidins and one new proanthocyanidin trimer from the PSE. The structure of the new compound (5) was determined by 1D- and 2D-NMR and mass spectrometry analyses, and was determined as epicatechin-(2ß→O→7,4ß→6)-epicatechin-(4ß→6)-epicatechin. The other known proanthocyanidins were identified as proanthocyanidin monomers (1), dimers (6-9), trimers (3-5) and tetramers (2, 10, 11). They showed suppressive activities against melanogenesis and cytokine production at concentrations ranging from 0.1-10 µg/mL. Among the tested compounds, suppressive activities of proanthocyanidin dimers or trimers in two assay systems were stronger than those obtained with monomer or tetramers. These data indicate that proanthocyanidin oligomers from peanut skin have the potential to reduce dermatological conditions such as inflammation and melanogenesis.