Human bronchial intraepithelial T cells produce interferon-gamma and stimulate epithelial cells.

Intraepithelial lymphocytes (IELs) can be identified among epithelial cells in systemic mucosal tissues. Although intestinal IELs play a crucial role in mucosal immunity, their bronchial counterparts have not been well studied. The purpose of this study was to determine the immunological functions of human bronchial IELs, which interact directly with epithelial cells, unlike lamina propria lymphocytes (LPLs). We isolated successfully bronchial IELs and LPLs using a magnetic cell separation system from the T cell suspensions extracted from bronchial specimens far from the tumours of resected lungs. Human bronchial IELs showed an apparent type 1 cytokine profile and proliferated more actively in response to CD2 signalling than did bronchial LPLs. CD8(+) IELs were identified as the most significant sources of interferon (IFN)-gamma. Human bronchial epithelial cells constitutively produced the T cell growth factors interleukin (IL)-7 and IL-15, and levels of those factors increased when cells were stimulated by IFN-gamma. Bronchial epithelial cells expressed cell surface proteins CD58 and E-cadherin, possibly enabling adhesion to IELs. In summary, human bronchial IELs have immunological functions distinct from bronchial LPLs and may interact with epithelial cells to maintain mucosal homeostasis.

Neutral endopeptidase inhibitors potentiate substance P- and capsaicin-induced cough in awake guinea pigs.

To study the roles of substance P and endogenous neutral endopeptidase in mediating cough, we measured cough responses in awake guinea pigs in response to exogenous substance P and capsaicin aerosols in the presence and absence of the neutral endopeptidase inhibitors leucine-thiorphan and phosphoramidon. Substance P stimulated cough in very low concentrations (10(-17)-10(-16) M). In a second study where the investigator did not know whether substance P or diluent alone was aerosolized, substance P (10(-16) M) caused cough. Leucine-thiorphan (10(-5) M) and phosphoramidon (10(-5) M) potentiated substance P-induced cough; NEP inhibitors also potentiated capsaicin-induced cough significantly. These findings suggest that substance P is a potent stimulator of cough responses, that capsaicin-induced cough is mediated by substance P or another similar neuropeptide, and that cough responses are modulated by endogenous neutral endopeptidase.

Recombinant human enkephalinase (neutral endopeptidase) prevents cough induced by tachykinins in awake guinea pigs.

To determine whether recombinant enkephalinase (neutral endopeptidase, EC 3.4.24.11) prevents cough induced by exogenously applied and endogenously released neuropeptides, we measured cough responses to aerosolized solutions of substance P or of capsaicin for 2 min in random-source guinea pigs before or after exposing them to aerosolized recombinant human enkephalinase. Substance P (10(-16) M) increased coughing compared with its vehicle. Enkephalinase (120 micrograms) inhibited cough induced by subsequent exposure to substance P compared with the response to substance P alone, but after further exposure to the enkephalinase inhibitor leucine-thiorphan (10(-5) M), substance P increased cough significantly. Similar results were obtained for capsaicin-induced cough. In pathogen-free guinea pigs, after they inhaled inactive recombinant enkephalinase (33 micrograms), capsaicin (10(-13) M) increased cough significantly. In contrast, after they inhaled active recombinant enkephalinase (33 micrograms), capsaicin increased cough only slightly. These results suggest that aerosolized enkephalinase reaches the sites of release or actions of endogenous neuropeptides and, by degrading them, prevents cough induced by their release. Furthermore, these studies suggest that recombinant enkephalinase might be useful in the treatment of cough and other symptoms of diseases involving peptides cleaved by this enzyme.

The role of substance P release in the lung with esophageal acid.

To investigate whether tachykinins are released in the airways by stimulating the esophagus, airway plasma extravasation induced by intraesophageal hydrochloric acid (HCl) in the presence or absence of the neutral endopeptidase (NEP) inhibitor phosphoramidon and the neurokinin-1-receptor antagonist FK888 was studied in anesthetized guinea pigs. Airway plasma extravasation also was studied in the presence of the NEP inhibitor in guinea pigs pretreated with capsaicin or bilateral vagotomy. Propranolol and atropine were used in all animals to block adrenergic and cholinergic nerve effects. Airway plasma leakage was evaluated by measuring extravasated Evans blue dye. One normal HCl infusion into the esophagus significantly increased plasma extravasation in the trachea. Phosphoramidon significantly potentiated plasma extravasation induced by HCl infusion into the esophagus in the trachea and main bronchi, and FK888 significantly inhibited extravasation in a dose-related manner. In capsaicin-treated animals, airway plasma extravasation was completely inhibited even in the presence of phosphoramidon. Tracheal plasma extravasation potentiated by phosphoramidon was significantly inhibited in the bilaterally vagotomized animals. These results suggest that locally acting substances are released by intraesophageal HCl stimulation that cause airway plasma extravasation. These substances are generated through activation of neural pathways, including some that traffic through the vagus nerves that link the esophagus or airways.

Interleukin-5 levels of pleural fluid and serum samples in a patient with PIE syndrome.

An increased production of IL-5 was detected in the pleural fluid (7.2 ng/ml) and in the serum samples (53 pg/ml) of a patient with PIE syndrome. Following steroid therapy, pleural fluid disappeared, eosinophilia improved and serum IL-5 concentration became undetectable. These results suggested that eosinophilia in the PIE syndrome is a consequence of increased production of IL-5, especially in the lung.

Neutral endopeptidase inhibitor potentiates allergic bronchoconstriction in guinea pigs in vivo.

To determine whether endogenous tachykinins are released in allergic airway response to contribute to bronchoconstriction and whether neutral endopeptidase (NEP), which effectively cleaves tachykinins, modulates that bronchoconstriction, we studied the effects of the NEP inhibitor phosphoramidon on bronchoconstriction induced by allergic response in anesthetized guinea pigs. We mechanically ventilated the guinea pigs sensitized with ovalbumin (OVA) in a bodyplethysmograph and measured the pulmonary resistance (RL). We exposed the sensitized guinea pigs to doubling concentrations of OVA aerosols from 2(-5)% (wt/vol) until the transpulmonary pressure increased more than twofold from the baseline. After the final exposure, we exposed them to phosphoramidon (10(-4) M) or its vehicle. Phosphoramidon significantly potentiated the increased RL induced by OVA challenge. Phosphoramidon also significantly potentiated the increased RL in the guinea pigs treated with atropine, but the potentiation was significantly reduced. In contrast, phosphoramidon failed to potentiate the increased RL induced by OVA in guinea pigs pretreated with capsaicin. These results suggest that 1) endogenous tachykinin-like substances are released in allergic airway response and that 2) when endogenous NEP is inhibited in the guinea pig airways in vivo, the substances contribute to bronchoconstriction by partly activating the parasympathetic nerve.

Neutral endopeptidase inhibitor potentiates endothelin-1-induced airway smooth muscle contraction.

To study the role of neutral endopeptidase (NEP) on endothelin-1-induced contraction of the airway smooth muscle, we examined the contractile effect of endothelin-1 in the isolated guinea pig trachea and human bronchus in the presence or absence of NEP inhibitor phosphoramidon. After incubation with phosphoramidon (10(-8) to 10(-5) M), we added endothelin-1 cumulatively from 10(-11) to 10(-7) M to the airway tissues in organ baths. Phosphoramidon significantly potentiated the endothelin-1-induced contraction in a concentration-dependent fashion in both guinea pig trachea and human bronchus, and it shifted the concentration-response curves to the left. Because NEP is known to cleave tachykinins, we next studied whether endothelin-1 contracts airway tissues by releasing endogenous tachykinins from bronchial C-fibers. After incubation with phosphoramidon (10(-5) M), we added endothelin-1 cumulatively from 10(-11) to 10(-7) M to the tissues that were treated with capsaicin to deplete the tachykinins. Phosphoramidon significantly potentiated the endothelin-1-induced contraction in the capsaicin-treated tissues, suggesting that endothelin-1 causes the contraction, at least in part, without releasing tachykinins. In contrast to the effect of phosphoramidon, captopril (an angiotensin-converting enzyme inhibitor), leupeptin (a serine protease inhibitor), and bestatin (an aminopeptidase inhibitor) did not modulate the effect of endothelin-1-induced contraction in both guinea pig trachea and human bronchus. From these results, we conclude that NEP plays an important role in regulating endothelin-1-induced contraction in the guinea pig trachea and human bronchus.

Evidence that PGF2 alpha-induced contraction of isolated guinea pig bronchi is mediated in part by release of tachykinins.

To investigate whether prostaglandin F2 alpha (PGF2 alpha) stimulates the release of tachykinins and whether the tachykinins play a role in the PGF2 alpha-induced bronchial contraction, we examined the contractile response to PGF2 alpha in the presence or absence of a neutral endopeptidase (NEP) inhibitor phosphoramidon in the guinea pig main bronchus in vitro. Because NEP effectively cleaves tachykinins, we hypothesized that the inhibition of NEP would enhance a PGF2 alpha-induced bronchial contraction if PGF2 alpha stimulates the release of tachykinins. Phosphoramidon significantly enhanced the concentration-response curve to PGF2 alpha. And it also significantly enhanced 10(-5) M PGF2 alpha-induced contraction. The enhancement was significantly attenuated in tissues where the tachykinins had been depleted by treatment with capsaicin. Furthermore, the enhancement of contraction was also significantly attenuated in the presence of tachykinin antagonist FK-224 (10(-5) M). Tetrodotoxin, a sodium-channel blocker that blocks nerve conduction, did not affect the enhancement. From these results we conclude that 1) PGF2 alpha causes the release of tachykinin-like substances, 2) these substances play a role in bronchial contraction in tissues where NEP activity is inhibited, and 3) nerve conduction is not necessary for the release of these substances in the guinea pig bronchus.

Esophageal stimulation by hydrochloric acid causes neurogenic inflammation in the airways in guinea pigs.

To investigate whether tachykinins are released in the airways in response to stimulation of the esophagus, we studied the airway plasma extravasation induced by intraesophageal HCl in the presence or absence of neutral endopeptidase inhibitor phosphoramidon and NK1-receptor antagonist FK-888 in anesthetized guinea pigs. The airway plasma leakage was evaluated by measuring extravasated Evans blue dye in the animals pretreated with propranolol and atropine. Infusion of 1 N HCl into the esophagus significantly increased plasma extravasation in the trachea. Phosphoramidon significantly potentiated plasma extravasation in the trachea and main bronchi, whereas FK-888 significantly inhibited that extravasation in a dose-related manner. In the capsaicin-treated animals, airway plasma extravasation was completely inhibited even in the presence of phosphoramidon. Tracheal plasma extravasation potentiated by phosphoramidon was significantly inhibited in the bilateral vagotomized animals. These results suggest that 1) tachykinin-like substances are released to cause plasma extravasation in the airways as a result of intraesophageal HCl stimulation and 2) there are neural pathways communicating between the esophagus and airways, including the vagus nerve.

Mechanisms accounting for granulomatous responses in hypersensitivity pneumonitis.

Hypersensitivity granuloma formation is an immunopathological feature of HP. It is induced by the T cell-mediated delayed-type hypersensitivity reaction to organic dusts or active chemicals invading the lung. Circulating, antigen-reactive, memory CD4+ T cells, generated by previous sensitization, migrate into lung parenchyma in response to chemokines such as RANTES. The T cells develop into either Th0, Th1, or Th2 effector depending upon the conditions in which they first encounter the antigens. The Th1 cells produce IL-2 and IFN-gamma. IFN-gamma can prime macrophages to transcribe and to secrete greater amounts of TNF and IL-1. The macrophages activated by TNF and IL-1 produce a wide range of biologically active mediators such as MAF, MCF, and MIF. These monokines attract young macrophages into the lesions, activate them, and young macrophages develop into mature macrophages, resulting in the hypersensitivity granuloma consisting of epithelioid cells and multinucleated giant cells. CD8+ T cells, the most predominant cell in the lesions of HP, may modulate the granuloma formation via the production of Th1-like or Th2-like cytokines.

Tachykinin antagonist FK224 inhibits neurokinin A-, substance P- and capsaicin-induced human bronchial contraction.

To determine the roles of endogenously released tachykinins (substance P [SP] and neurokinin A [NKA]) in the human bronchial tissues, we studied the effects of tachykinin antagonist FK224 on bronchial smooth muscle contraction induced by SP, NKA and capsaicin in an organ bath. FK224 (10(-6) M and 10(-5) M, respectively) significantly inhibited NKA-induced contraction and 10(-5) M FK224 shifted the dose-response curve to more than one log unit higher concentration. Because SP- and capsaicin-induced contractions were small, we pretreated the tissues with the neutral endopeptidase inhibitor phosphoramidon (10(-5) M), which inhibits degradation of exogenous tachykinins in order to potentiate the contractions. FK224 (10(-5) M) significantly inhibited SP-induced contraction and it shifted the dose-response curves to about one log unit higher concentration. FK224 (10(-5) M) also significantly inhibited capsaicin-induced contraction and it shifted the dose-response curves to more than one log unit higher concentration. In contrast, FK224 (10(-5) M) did not affect on acetylcholine-, histamine-, and leukotriene D4-induced contraction. These results suggest that FK224 is a tachykinin receptor antagonist in the human bronchial smooth muscle, and that capsaicin-induced contraction is due to endogenously released tachykinin-like substances in the human bronchus.

Atypical peritracheobronchial vasculitis and an effective treatment.

We report an interesting case of vasculitis in which the inflammatory lesion was limited to the peritracheobronchus. This case showed positive antineutrophil cytoplasmic antibodies, diffuse peritracheobronchial swelling, and vasculitis in its histology. Steroid therapy was effective for both roentgenological and serological findings. Although the biopsy specimen shows only inflammation and does not satisfy the WHO criteria of Wegener's granulomatosis (WG), a possible diagnosis of WG should not be disregarded.

[Lack of knowledge about smoking-related risks for diseases in the general public in Japan].

Cigarette smoking is the primary preventable cause of various diseases and death. Smoking has been causally related to lung cancer, other malignancies, atherosclerosis, coronary heart disease, and chronic obstructive pulmonary disease. There have been few studies, however, of whether the ordinary citizen in Japan understand the risks of serious diseases caused by smoking. Four hundred and thirty six people attended a seminar of respiratory diseases entitled "Cigarette smoking and lung cancer; prevention and treatment of asthma; senile care and prevention of pneumonia". After the seminar, unsigned questionnaires were filled out by 403 of those in attendance. Three hundred eighty nine (165 males and 224 females) respondents correctly answered the questionnaires, and these were analyzed in the study. Attendants comprised 243 who had never smoked (63%), 99 former smokers (25%), and 39 current smokers (10%). Three hundred forty seven attendants (89%) answered that smoking is harmful to the health, and 371 (95%) that it is causally related to lung cancer. In contrast, lower numbers of attendants answered that smoking is causally related to other diseases: pulmonary emphysema, 65% of the responses; chronic bronchitis, 68%; laryngeal cancer, 77%; myocardial infarction, 53%; and atherosclerosis, 49%. Of the 39 current smokers, 27 answered that they would stop smoking after the seminar. Although many people partly understand the risks of smoking, they do not have a clear knowledge of the risks of diseases besides lung cancer. Education about the risks of smoking and about smoking cessation is required.

[Preventive effect of a novel leukotrienes antagonist ONO-1078 on leukotriene C4- and D4-induced human bronchial smooth muscle contraction].

To study whether a novel leukotrienes antagonist ONO-1078 (4-oxo-8-[4-phenylbutyloxy) benzoylamino]-2-(tetrazol-5-yl)-4H-1-benzopyran hemihydrate) prevents leukotrienes C4- and D4-(LTC4, LTD4) induced human bronchial smooth muscle contraction, we examined the bronchial contractile response to LTC4 and LTD4 in the presence or in the absence of ONO-1078 in human bronchial strips. We prepared 4 strips from each of 5 patients undergoing lobectomy of the lung because of lung cancer. We mounted the strips in organ baths and measured the contractile response to LTC4 and LTD4 from 10(-11) M to 10(-7) M after incubation with ONO-1078 (10(-8) M, 10(-7) M and 10(-6) M) and without ONO-1078. ONO-1078 shifted the dose response curve to LTC4 to higher concentration in dose dependent fashion, and it significantly inhibited the contractile response to LTC4 and LTD4. In the presence of L-serine borate complex (45 mM), an inhibitor of gamma-glutamyl transpeptidase, ONO-1078 significantly inhibited the LTC4-induced contraction. On the other hand, ONO-1078 had no effect on the contractile response to acetylcholine. These results suggest that ONO-1078 is a specific antagonist of LTC4 and LTD4 receptors in human bronchial smooth muscle. Because the effect of LTC4 and LTD4 is thought to be an important part of the pathogenesis of bronchial asthma, our results also suggest that ONO-1078 may be a useful prophylactic drug for bronchial asthma.

[Prevalence of asthma in adults in Menda town rural-mountain area in Japan].

Several reports have suggested that the prevalence of asthma in adults is currently increasing. However, recent prevalence of asthma has not reported in Japan, especially in rural-mountain areas. To investigate the prevalence of asthma in adults in Japan, we conducted clinical epidemiological research on 5066 inhabitants of Menda town, in a rural-mountain area of Japan. The study population comprised 98.7% of adults in the town, including senior high school students whose age were more than 15 years old. The prevalence of asthma among adults was 3.6%. The ratio of prevalence in males to prevalence in females was 1.44. Peaks prevalences were observed in the age ranges of 15-19 and > 70 years old in males, and 15-19, 40-49 and > 70 years old in females.

Use of tacrolimus, a potent antifibrotic agent, in bleomycin-induced lung fibrosis.

Idiopathic pulmonary fibrosis has a poor prognosis and few efficacious treatments. The immunosuppressant cyclosporin A has been shown to inhibit tumour growth factor (TGF)-beta-induced collagen deposition in vitro, and is widely used in Japan as a potent antifibrotic agent. Tacrolimus (FK506) is another attractive immunosuppressant, which may be useful in the treatment of pulmonary fibrosis. The aim of the present study was to elucidate the antifibrotic effect of FK506. The inhibitory effect of FK506 on collagen synthesis in cultured lung fibroblastic cells, TIG-3-20, and its antifibrotic effect on bleomycin (BLM)-induced pulmonary fibrosis in mice was investigated. FK506 inhibited TGF-beta-induced collagen synthesis, and suppressed the expression of TGF-beta type I receptor (TbetaR-I) in TIG-3-20 cells. Consistent with the in vitro findings, FK506 treatment starting on day 6 attenuated BLM-induced pulmonary fibrosis, in part, via reduced TbetaR-I expression. FK506 treatment in the acute BLM injury phase unexpectedly increased pro-inflammatory cytokine levels in bronchoalveolar lavage fluid and enhanced lung injury, resulting in poor survival. In conclusion, the present results suggest that FK506 has a potent antifibrotic effect and may be useful for the treatment of pulmonary fibrosis, although its use in the acute inflammatory phase may exacerbate lung injury.

A new look at hypersensitivity pneumonitis.

Hypersensitivity pneumonitis is an immunologically induced lung disease. Although both immune complex-mediated immune response and T cell-mediated immune response are involved in the pathogenesis of the disease, recent studies show the latter mechanism to be more important. As for T cell-mediated immune response, Th1/Th2 and Tc1/Tc2 cytokines produced by CD4+ and CD8+ T cells play important roles in the development of granulomatous inflammation in the lung, a pathologically characteristic feature of the disease. The critical distinction between CD4+ and CD8+ T cells pertains to recognition of antigens presented by different major histocompatibility complex molecules. Serum levels of KL-6 and soluble intercellular adhesion molecule-1 in patients with HP are useful markers of the disease activity. The chronic form of HP can be difficult to diagnose, and provocation testing is helpful. Erythromycin might be useful for anti-inflammatory therapy.