Sanae Shimura

Pulmonary Function and Regional Distribution of Emphysema as Determined by High-Resolution Computed Tomography

In patients with pulmonary emphysema, emphysematous changes are not uniform and vary from minimum alveolar destruction to advanced bullous formation, depending on the lobe or site in the lungs. However, we have little knowledge on whether or how this nonuniformity or localization affects pulmonary function in PE patients. Therefore, we measured the computed tomography (CT) density of divided sites in lungs with high-resolution CT images from 25 PE patients (FEV1.0%, mean ± SD 36 ± 9%, %DLCO 48 ± 16%, all men, 68 ± 4 years) and compared them to various parameters of pulmonary function. The mean CT density of whole lungs correlated with 12 pulmonary function parameters including FEV1.0 and diffusion capacity. When both lung fields were divided into peripheral, intermediate and central portions, the CT density of the central portion correlated with all pulmonary function parameters with which CT density of whole lungs correlated. In contrast, the CT density of the peripheral portion significantly correlated with only 7 parameters with smaller correlation coefficient values than those of the central portion. When divided into upper, middle and lower portions, the CT densities of upper, middle and lower portions correlated with 6, 8 and 10 of the 12 pulmonary function parameters which correlated with the density of whole lungs, respectively. The delta value of CT densities between the upper and lower portions or between the lateral and medial portions correlated with obstructive impairment (FEV1.0 and FEV1.0%). These findings suggest that (1) central rather than peripheral emphysematous changes affect pulmonary function, and (2) uniformity of emphysematous change correlates with the severity of airway obstruction in PE patients.

Pulmonary Emphysema followed by Pulmonary Fibrosis of Undetermined Cause

Idiopathic pulmonary fibrosis (IPF) and pulmonary emphysema (PE) have distinct clinical and pathological characteristics, and have been considered to be separate disorders. However, recent animal experiments have suggested that, with regard to their pathogenesis, the diseases have some features in common. However, there are no clinical data supporting this hypothesis. We report here 9 patients (all male, 67 +/- 2 years, mean +/- SE) who had PE followed by IPF. They were found among 152 PE patients who came to Tohoku University Hospital during the past 15 years (1976-1991). All patients were male and heavy smokers and 2 patients also had prostate cancer and gastric cancer, respectively. Three patients were alive during this study and had been diagnosed as having IPF and PE by the combination of transbronchial biopsy, selective alveolobronchogram, CT examination and lung function tests. The diagnosis of IPF and PE in the other patients was based on the pathological findings of autopsied lungs in addition to clinical findings. All patients showed PE mainly in the upper lobes and IPF in the lower lobes. In all patients, in addition to all known causes of pulmonary fibrosis, the possibilities that chronic or recurrent infections in PE induced pulmonary fibrosis and that IPF produced emphysematous changes were carefully excluded by medical records and pathological findings. It is not clear whether the occurrence of emphysema and pulmonary fibrosis in these cases is coincidental, or whether the two diseases are linked by a common pathogenetic pathway.

Nitric oxide regulation of glycoconjugate secretion from feline and human airways in vitro

To determine whether nitric oxide (NO) regulates mucus secretion from airway submucosal glands which are the main source of human airway secretion, we examined the effects of NO synthase inhibitors (L-NAME and L-NMMA) on mucus glycoprotein (MGP) secretion from feline and human airway explants (with epithelium) and isolated submucosal glands. MGP secretion was estimated by measuring trichloroacetic-acid (TCA) precipitable [H3]-glycoconjugates using secretory indices. NO synthase inhibitors alone did not alter significantly MGP secretion from explants or isolated glands. Pretreatment with NO synthase inhibitors significantly inhibited both methacholine (MCh) and bradykinin (BK)-induced secretion from isolated glands, but not significantly inhibit the secretion from explants. The inhibition by L-NAME was reversed by the addition of L-arginine in both MCh- and BK-induced secretions from isolated glands. Further, a NO generator isosorbide dinitrate induced a significant increase in the secretion. These findings suggest that endogenous NO has a stimulatory action in airway submucosal gland secretion and directly regulates the secretion from submucosal glands independently of superficial epithelial cells.

ATP-induced Cl− secretion with suppressed Na+ absorption in rabbit tracheal epithelium

The effect of extracellular ATP on ion transport of rabbit tracheal epithelium was examined using an Ussing chamber. Isoproterenol (10(-8)-10(-5) M) did not alter the electrophysiological properties across the tracheal epithelium. Apically applied ATP induced an initial transient increase in short circuit current (SCC) followed by a decline to below the prior baseline. The initial increase by ATP (10(-4) M) was significantly inhibited by a Cl(-) -channel inhibitor diphenylamine-2-carboxylate (DPC, 5 x 10(-4) M) and Cl(-) -substitution with gluconate in the bath solution, while a cystic fibrosis transmembrane regulator (CFTR) Cl(-) -channel inhibitor glibenclamide (10(-4) M), a Na(+)-channel inhibitor amiloride (10(-4) M) and a K(+) -channel inhibitor quinidine (10(-4) M) all failed to alter it. The decline in SCC by ATP was abolished by amiloride, while DPC or Cl-substitution with gluconate in the bath solution did not alter it. Ca(2+)-removal from the bath solutions did not significantly alter the initial increase nor the decline by ATP. Ionomycin (10(-5) M) induced an initial transient increase in SCC, to a degree similar to that by ATP alone. A calmodulin antagonist W-7 reduced the SCC baseline and abolished SCC increase by ATP. These findings indicate that ATP activates Ca(2+)-dependent Cl(-) -channels with an inhibition of Na -channel activity or absorption in rabbit tracheal epithelium.

Glucocorticoids suppressed production and gene expression of interleukin-5 by peripheral blood mononuclear cells in atopic patients and normal subjects

BACKGROUND Interleukin-5 (IL-5) is known to play a major role in regulating eosinophil function in atopic diseases, including bronchial asthma. Glucocorticoids are most effective agents for treating these diseases. However, their mechanism remains unclear. We examined the effects of glucocorticoids on the production and gene expression of IL-5 in atopic patients and normal subjects. METHODS Human peripheral blood mononuclear cells (PBMCs) in five atopic and four normal subjects were cultured with phytohemagglutinin and phorbol 12-myristate 13-acetate (PMA) in the presence of dexamethasone. IL-5 secreted by PBMCs was assayed by ELISA. Gene expression of IL-5 by PBMCs was assessed semiquantitatively by sequential reverse transcription-polymerase chain reaction, and Southern blot analysis. RESULTS Phytohemagglutinin/PMA-stimulated PBMCs from all atopic patients and three normal subjects secreted detectable amounts of IL-5, which were suppressed by dexamethasone in a dose-dependent manner, with 85.8% suppression at 10(-6) mol/L. Gene expression of IL-5 was detected by reverse-transcription polymerase chain reaction in PBMCs from all subjects, even when not stimulated; was increased by stimulation; and was suppressed by dexamethasone. The concentration of dexamethasone resulting in 50% inhibition in IL-5 gene expression did not differ between atopic patients and normal subjects. CONCLUSION These findings indicate that dexamethasone suppressed IL-5 production in atopic human PBMCs through an inhibitory action on the gene expression. These results suggest that the suppression of IL-5 production through the suppression of IL-5 gene expression is one of the most important mechanisms by which glucocorticoids inhibit eosinophil functions in the treatment of atopic diseases, including bronchial asthma.

Dexamethasone suppressed gene expression and production of interleukin-10 by human peripheral blood mononuclear cells and monocytes

Interleukin-10 (IL-10) is known to inhibit T cell-mediated responses. IL-10 has also been shown to play an important pathogenetic role in allergic diseases. Glucocorticoid is known to inhibit the production and gene expression of many cytokines which induce inflammatory reactions. We examined the effect of dexamethasone on the gene expression and production of IL-10 by human peripheral blood mononuclear cells (PBMCs) and monocytes. PBMCs and monocytes from 5 healthy volunteers were incubated with or without dexamethasone for 1 h, then stimulated with 5 micrograms/ml lipopolysaccharide (LPS). Gene expression and production of IL-10 by human PBMCs were detected without stimulation and increased by LPS stimulation. Dexamethasone suppressed the gene expression and production of IL-10 by LPS-stimulated PBMCs in a dose-dependent manner by 41.6 and 61.1% at 10(-6) M, respectively. Also in monocytes, the gene expression and production of IL-10 were detected without stimulation, increased by LPS stimulation, and significantly suppressed by dexamethasone by 53.1 and 61.2% at 10(-6) M, respectively. This suppressive effect on IL-10 gene expression was not so potent compared with its effect on cytokines such as IL-5. The suppression of IL-10 production by glucocorticoid is suggested to be one of the important mechanisms by which glucocorticoids suppress allergic inflammation in the treatment of allergic diseases.

Role of Cyclic ADP-Ribose in ATP-activated Potassium Currents in Alveolar Macrophages

There is growing evidence that extracellular ATP causes a dramatic change in the membrane conductance of a variety of inflammatory cells. In the present study, using the nystatin perforated patch recording configuration, we found that ATP (0.3–30 μm) induced a transient outward current in a concentration-dependent manner and that the reversal potential of the ATP-induced outward current was close to the K+ equilibrium potential, indicating that the membrane behaves like a K+ electrode in the presence of ATP. The first application of ATP to alveolar macrophages perfused with Ca2+-free external solution could induce the outward current, but the response to ATP was diminished with successive applications. Intracellular perfusion with a Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, also diminished the response. When cyclic ADP-ribose (cADPR) was applied to the macrophage cytoplasm, a transient outward current was elicited. Thereafter, the successive outward current was inhibited, suggesting the involvement of cADPR in the response. Intracellular perfusion with inositol 1,4,5-trisphosphate also induced a transient outward current, but the successive current was not inhibited. The ATP-induced outward current was abolished when 8-amino-cADPR (as a blocker of cADPR, 10−6–10−5 m) was introduced into the cytoplasm. Homogenates of alveolar macrophages showed both ADP-ribosyl cyclase and cADPR hydrolase activities, and CD38 (ADP-ribosyl cyclase/cADPR hydrolase) expression was confirmed by reverse transcriptase-polymerase chain reaction and Western blot analyses. These results indicate that ATP activates K+currents by releasing Ca2+ from cADPR-sensitive internal Ca2+ stores.

Surfactant apoprotein-A concentration in sputum for diagnosis of pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP), a disease characterised by accumulation of surfactant in alveoli, is diagnosed on the basis of invasive biopsy procedures. We have measured apoprotein A (SP-A) concentrations in sputum to see if this is useful for the diagnosis of PAP. Sputum samples from three patients with PAP and twenty patients with other pulmonary disease were assayed using monoclonal antibodies to SP-A. SP-A concentrations were 400 times higher in patients with PAP than in the controls, suggestions that this measurement is useful for the diagnosis of PAP especially where lung biopsy is contraindicated.

Signal transduction of mucous secretion by bronchial gland cells.

Bronchial glands, which consist of mucous and serous cells, are abundant in human airways, playing a major role in the airway secretion. Cl(-) secretion is accompanied by water transport to the lumen in the acinar cells of bronchial glands. Agonists that increase [Ca(2+)]i induce the Cl(-) secretion in bronchial glands. Ca(2+) release from a IP(3)-sensitive Ca(2+) pool at the apical portion stimulates and opens Ca(2+)-sensitive Cl(-) channels at the apical membrane, producing Cl(-) secretion in bronchial glands. K(+) channels at the basolateral membranes are Ca(2+)-sensitive and activated by Ca(2+) release from a cADPribose-sensitive Ca(2+) pool, maintaining the Cl(-) secretion in bronchial glands. Further, cADP ribose in concert with IP(3) induce [Ca(2+)]i oscillation, inducing Cl(-) secretion in bronchial glands. Some tyrosine kinases are involved in the Cl(-) secretion in bronchial glands. Mucous and serous cells in bronchial glands take part in mucin secretion and the secretion of defensive substances (glycoconjugates), respectively. [Ca(2+)]i oscillations are shown to play a central role in the exocytosis of secretory granules in serous cells of bronchial glands. Other signal transductions of mucin and glycoconjugates in airway gland cells remain to be studied, although agonists which increase [cAMP]i are also well known to induce mucin and glycoconjugate secretion from airway glands.

Methacholine Bronchial Hyperresponsiveness inChronic Sinusitis

The coexistence of chronic sinusitis (CS) may deteriorate the clinical condition of lower airway diseases such as bronchial asthma (BA) or chronic bronchitis (CB). However, the bronchial hyperresponsiveness (BH) in CS without any apparent lower airway disease is not fully understood nor are the effects of treatment. We examined lower airway hyperresponsiveness to methacholine (MCh) in 42 subjects with CS but without allergic rhinitis (AR) who had normal lung functions without any pulmonary symptoms, comparing it with that of 50 subjects with stable BA, 50 subjects with simple CB and 40 subjects with AR, and further examined the effect of endoscopic sinus surgery in 7 CS subjects with BH. The BH to MCh was measured in terms of the minimum dose (Dmin), defined as the cumulative dose at the point where respiratory conductance began to decrease. A Dmin <50 units was defined as BH. Seventy-one percent of CS subjects showed BH without relation to the severity or duration of CS, or atopic status. BH in CS subjects, which was less than that in BA subjects, was similar to that in simple CB or AR in both its prevalence and degree. After the surgical treatment of CS, BH significantly decreased (p < 0.01) with improvements in both nasal symptoms and sinus lesions. These findings suggest that CS itself induces BH to a degree similar to simple CB and AR without any relationship to the clinical background, and that adequate treatment of CS reduces BH.