Takayuki Ohtoshi

Diesel exhaust particles stimulate human airway epithelial cells to produce cytokines relevant to airway inflammation in vitro

BACKGROUND Epidemiologic and experimental studies suggest that air pollution such as diesel exhaust particles (DEPs), one of the important air pollutants, may play a role in the increasing prevalence of allergic airway diseases. OBJECTIVE We studied the effect of suspended particulate matter (SPM) and its main component, DEPs, on the production of IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) by human airway epithelial cells in vitro. METHODS SPM obtained from high-volume air samplers and DEPs were added to cultured human nasal polyp-derived upper airway, normal bronchial, and transformed bronchial epithelial cells. Production of GM-CSF and IL-8 by airway epithelial cells was evaluated. RESULTS Nontoxic doses of DEPs showed a significant stimulatory effect on IL-8 and GM-CSF production by these three kinds of epithelial cells in a dose- and time-dependent fashion. SPM had a stimulatory effect on GM-CSF, but not IL-8, production. These effects were abrogated by treatment with a protein synthesis inhibitor, cycloheximide, suggesting that the process required a de novo protein synthesis. On the double-chamber plates, airway epithelial cells responded to DEPs only when they were stimulated from the apical sides, which can be a model for in vivo environments. Neither charcoal nor graphite showed such stimulatory effects, indicating that the activity of DEPs did not derive from their particulate nature. Benzo(a)pyrene, one of the main aromatic hydrocarbons contained in DEPs, showed a stimulatory effect on the release of the cytokines, and this organic substance might have a causative effect on of the potency of DEPs. CONCLUSION We conclude that SPM and DEPs, its main component, might be important air pollutants in the activation of airway epithelial cells for the release of cytokines relevant to allergic airway inflammation.

Endotoxin and pro-inflammatory cytokines stimulate endothelin-1 expression and release by airway epithelial cells.

Endothelin is a potent bronchoconstrictor peptide first identified as a novel vasoconstrictor produced by vascular endothelial cells. Recent reports suggest that airway epithelial cells are also capable of releasing this active peptide. To investigate the regulatory mechanism of endothelin expression, we studied the effects of endotoxin and pro‐inflammatory cytokines such as interleukin‐1 and tumour necrosis factor on the expression and release of endothelin‐1 by airway epithelial cells. Both endotoxin and the cytokines stimulated endothelin‐1 release by human bronchial epithelial cells. Northern blot analysis showed increased expression of preproendothelin‐1 mRNA by these factors. These results suggested that airway epithelial cells might play a role in the local airway smooth muscle tone through the production of endothelin, which might be upregulaled by inflammatory products in the airways.

IgE antibody‐mediated shock reaction caused by topical application of chlorhexidine

A case of an anaphylactic shock following topical application of chlorhexidine preparation is reported. Specific skin‐sensitizing antibodies against chlorhexidine were demonstrated in the serum from the patient by a passive transfer test. IgE antibodies against chlorhexidine were also detected by radioallergosorbent technique (RAST). Paper discs conjugated with chlorhexidine‐HSA (human serum albumin) significantly bound the IgE antibodies. Furthermore, all of the sera from seven other patients with shock reactions following the topical application of chlorhexidine preparation also showed high RAST counts. Both chlorhexidine gluconate and chlorguanide which represents approximately half a molecule of chlorhexidine inhibited the reaction in a dose‐dependent fashion. It is suggested that the shock reactions following topical application of chlorhexidine are mediated by IgE antibodies against chlorhexidine and that chlorhexidine and chlorguanide share the same antigenic determinant.

Diesel exhaust particles activate human bronchial epithelial cells to express inflammatory mediators in the airways: a review.

Epidemiological as well as experimental studies suggest that particulate air pollutants, including diesel exhaust particles (DEP), may play a role in the recent increase of respiratory morbidity and mortality. We studied the effect of DEP on the production of inflammatory cytokines and mediators including IL‐8 and granulocyte macrophage colony stimulating factor (GM‐CSF) by human airway epithelial cells in vitro.

Histamine Activates Bronchial Epithelial Cells to Release Inflammatory Cytokines in vitro

Airway epithelial cells have a potential to produce cytokines which are relevant to airway inflammation. To elucidate the mechanisms of their regulation, we focused on the effects of three chemical mediators [histamine, platelet-activating factor (PAF) and endothelin-1] important in the pathogenesis of bronchial asthma. Histamine, but not PAF or endothelin-1, showed a dose-dependent stimulatory effect on the release of interleukin-6, interleukin-8 and granulocyte-macrophage colony-stimulating factor by normal and transformed human bronchial epithelial cells when studied 6 h after the treatment. The process required protein synthesis as evaluated by the effect of cycloheximide, and was mainly via H1 receptor. We concluded that histamine might be involved in the activation of airway epithelial cells to release inflammatory cytokines in allergic responses.

Topical thrombin-induced IgE-mediated anaphylaxis: RAST analysis and skin test studies☆

Bovine topical thrombin (BTT) is a heterologous plasma thrombin concentrate that has been frequently used for the hemostasis since the 1940s. Recently, three patients in Japan went into shock after the topical application of BTT at lesion sites, and two of these patients had received BTT repeatedly. The clinical symptoms and the increased anti-BTT percent RAST counts suggest that these reactions were shock mediated by anti-BTT IgE antibodies. The RAST-inhibition analysis suggested that the antigenic substance(s) were bovine-specific moiety(ies) mainly involved in the contaminant rather than bovine thrombin itself. The skin tests were studied to predict such allergic reactions. The intracutaneous test provoked nonspecific reactions even at the low concentrations of BTT. The prospective study on the predictive value of the prick test with 1000 U/ml (1 mg/ml) of BTT in 192 patients suggested that it is useful to detect highly sensitive patients. In addition, the increased levels of anti-BTT IgE antibodies in patients 1 month after the single administration of BTT suggested the immunogenicity of the topical application of BTT.

Erythromycin and clarithromycin attenuate cytokine-induced endothelin-1 expression in human bronchial epithelial cells

Erythromycin and its fourteen-member macrolide analogues have attracted attention for their efficacy in bronchial asthma. However, their mechanisms of action remain unclear. We evaluated the effects of the macrolide antibiotics on endothelin-1 (ET-1) expression in normal and transformed human bronchial epithelial cells, one of the sources of this potent bronchoconstrictor important in the pathogenesis of asthma. Human bronchial epithelial cells were obtained from the resected bronchi, and the effect of several antimicrobial and antiasthmatic drugs on the production and messenger ribonucleic acid (mRNA) levels of ET-1 was evaluated. Bronchoepithelial cells were also isolated from the mucosa of asthmatic patients under fibreoptic bronchoscopy, and the modulating effects of the drugs were studied. Erythromycin and clarithromycin uniquely suppressed mRNA levels as well as the release of ET- at therapeutic and non-cytotoxic concentrations (percentage inhibition of ET-1 protein release: 26.4+/-5.22% and 31.2+/-7.45%, respectively, at 10(-6) M). Furthermore, erythromycin and clarithromycin inhibited ET-1 expression in bronchoepithelial cells from patients with chronic, stable asthma. A glucocorticosteroid, dexamethasone, also inhibited ET-1 expression. In contrast, theophylline, salbutamol and FK506 had no effect on ET-1 production. Our findings demonstrated that these fourteen-member macrolide antibiotics had an inhibitory effect on endothelin-1 expression in human bronchial epithelial cells. Moreover, this new mode of action may have some relevance to their clinical efficacy in bronchial asthma.

Human Upper Airway Epithelial Cell-Derived Granulocyte-Macrophage Colony-Stimulating Factor Induces Histamine-Containing Cell Differentiation of Human Progenitor Cells

Nasal polyps and allergic rhinitis are upper airway inflammatory conditions characterized by increased numbers of eosinophils and metachromatic cells in the epithelial layer of the nasal mucosa. The objective of the current studies was to investigate the potential contribution of epithelial cells to the accumulation of inflammatory cells in the tissue. We have established pure cultures of human upper airway epithelial cells from normal and inflamed nasal polyps and allergic rhinitis tissue and examined the ability of conditioned medium from these cells (EpCM) to induce differentiation of human hemopoietic progenitors in vitro. We show that, under appropriate culture conditions, EpCMs, particularly those from cells derived from inflamed tissues, induce histamine-containing cell differentiation of cells of the human HL-60 myeloid leukemia cell line. These EpCMs also induce the emergence of both eosinophil/basophil and granulocyte/macrophage colonies in methylcellulose cultures of human peripheral blood mononuclear cells. We also show that CMs from epithelial cells derived from inflamed tissues contain greater amounts of granulocyte-macrophage colony-stimulating factor (GM-CSF) compared to CMs from normal epithelial cells. Finally, we show that the histamine-containing cell differentiation of HL-60 cells as well as the colony growth induced by EpCM can be fully inhibited by preincubating this CM with a monoclonal neutralizing antibody to human GM-CSF. These studies: (a) illustrate the ability of human upper airway epithelial cells to secrete GM-CSF in vitro; (b) demonstrate differences between normal and inflamed tissue-derived epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin 6B cell stimulatory factor-II is expressed and released by normal and transformed human bronchial epithelial cells

Airway epithelial cells have a potential to participate in local immune and inflammatory responses via releasing biologically active compounds. We studied the expression and release of interleukin 6 (IL-6), a multifunctional cytokine possibly involved in tissue immune responses. Primary culture of normal human bronchial epithelial cells and its transformed cell line BEAS-2B released significant amount of biologically and immunologically intact IL-6 into media. A protein synthesis inhibitor cycloheximide abolished the IL-6 release, suggesting a de novo synthesis. Northern blot analysis demonstrated the expression of the specific IL-6 mRNA. Human bronchial epithelial cells can produce IL-6 and contribute to the local activity of IL-6, suggesting that these cells may play a role in the regulation of airway immune responses.

Cefotiam-induced IgE-mediated occupational contact anaphylaxis of nurses ; case reports, RAST analysis, and a review of the literature.

Cefotiam (CTM) is one of the most popular cephem antibiotics in Japan. Recently we experienced two cases of nurses with CTM‐induced contact anaphylaxis. When they were preparing drip infusions of antibiotics or working around other nurses doing so, they suddenly fell into shock with other symptoms such as flushing, urtiearia, abdominal distress, vomiting, dyspnoea and or loss of consciousness. The symptoms never occurred after they avoided exposure to CTM. Passive cutaneous or open patch tests were positive for CTM. Histamine release was induced by CTM from washed leucocytes. RAST analysis using CTM‐human serum albumin‐coupled dises showed high % RAST count, suggesting that these reactions were mediated by IgE antibodies. A RAST inhibition test suggested that the methyl‐thiotetrazol side‐chain was the main antigenic determinant. Both patients had hand dermatitis that had appeared preceding the episodes of anaphylaxis. Although the dermatitis had been resistant to treatments, it also disappeared after they avoided exposure to CTM, It seemed likely that it was also induced or exacerbated by CTM and facilitated the penetration of CTM to cause anaphylaxis. The literature is also reviewed.