Takashi Mifune

Influence of age and disease severity on high resolution CT lung densitometry in asthma

BACKGROUND Low attenuation areas (LAA) on computed tomographic (CT) scans have been shown to represent emphysematous changes in patients with chronic obstructive pulmonary disease (COPD). However, the significance of LAA is still controversial in patients with asthma. This study was undertaken to assess the usefulness of lung CT densitometry in the detection of airspace enlargement in association with asthma severity. METHODS Forty five asthmatic subjects and 15 non-smoking controls were studied to determine the influence of age, pulmonary function, and asthma severity on mean lung density (MLD) and the relative area of the lung showing attenuation values less than –950 HU (RA950) on high resolution CT (HRCT) scans. RESULTS In asthmatic patients both MLD and RA950 correlated with parameters of airflow limitation (%FEV1, FEV1/FVC, %FEF25–75) and lung volume (%TLC, %FRC, %RV), but not with lung transfer factor (%Tlco, %Tlco/VA). The results of HRCT lung densitometry also correlated with patient age and severity of asthma. CONCLUSIONS Decreased CT lung density in non-smoking asthmatics is related to airflow limitation, hyperinflation and aging, but not with lung transfer factor.

Changes in the Proportions of Bronchoalveolar Lymphocytes, Neutrophils and Basophilic Cells and the Release of Histamine and Leukotrienes from Bronchoalveolar Cells in Patients with Steroid-Dependent Intractable Asthma

The proportion of inflammatory cells in bronchoalveolar lavage (BAL) fluid and the release of chemical mediators from BAL and peripheral blood cells were examined in 40 patients with steroid-dependent intractable asthma (SDIA) to clarify the effects of a long-term glucocorticoid regimen on these cells. The proportion of BAL lymphocytes was significantly reduced (p < 0.01) and the proportion of BAL neutrophils was significantly increased (p < 0.01) in SDIA patients compared with non-SDIA patients. The proportion of basophilic cells (mast cells and basophils) in BAL fluid was significantly lower in SDIA patients compared to non-SDIA patients (p < 0.02). The values of six ventilatory parameters were significantly lower in SDIA patients with a high proportion of BAL neutrophils (more than 10%) compared with the values in non-SDIA patients. The release of histamine and leukotriene C4 (LTC4) from the BAL cells of patients with atopic asthma was significantly reduced in SDIA patients compared with non-SDIA patients (p < 0.05). These results show that the changes in the proportion of BAL cells are observed in patients with SDIA, and these changes are related to suppressed ventilatory function and a reduction in the release of histamine and LTC4 from BAL cells.

Mucus Hypersecretion and Eosinophils in Bronchoalveolar Lavage Fluid in Adult Patients with Bronchial Asthma

Mucus hypersecretion was clinically analyzed in 46 adult patients with bronchial asthma, including 22 with steroid-dependent intractable asthma (SDIA). A large amount of expectoration, over 50 ml/day, was observed in 16 of these patients (34.8%), of whom 12 (75.0%) had SDIA and 13 (81.3%) were women. The mean amount of expectoration increased with increasing patient age, although no significant difference was found among the six age groups. A large amount of expectoration (over 50 ml/day) was clearly correlated with an increased proportion of eosinophils in bronchoalveolar lavage (BAL) fluid. The proportion of BAL eosinophils was significantly higher in patients with expectoration between 50 and 99 ml/day (p < 0.05) and over 100 ml/day (p < 0.01) than in patients whose expectoration volume was between 30 and 49 ml/day. These results show that in bronchial asthma patients, mucus hypersecretion is more often observed clinically in those with SDIA and in women, and that this hypersecretion is closely correlated with BAL eosinophilia, which is a feature of the pathophysiological changes that occur in the airways of these patients.

Effects of Perilla Seed Oil Supplementation on Leukotriene Generation by Leucocytes in Patients with Asthma Associated with Lipometabolism

Background: Dietary sources of α-linolenic acid, such as perilla seed oil, may have the capacity to inhibit the generation of leukotrienes (LTs) by leucocytes in patients with asthma, as has been reported with the consumption of other long-chain n-3 fatty acids. Methods: The factors affecting the suppression of leukotriene (LT) C4 generation by leucocytes were examined by comparing the clinical features of patients with asthma who had been given dietary perilla seed oil (n-3 fatty acids). Group A consisted of patients in whom the leucocyte generation of LTC4 was suppressed by dietary perilla seed oil. Group B consisted of those in whom LTC4 generation was not suppressed. Results: LTC4 generation by leucocytes decreased significantly in group A after 2 (p < 0.05) and 4 weeks (p < 0.05); conversely, it increased significantly in group B after 4 weeks (p < 0.05). The two study groups differed significantly in terms of LTC4 generation by leucocytes after 4 weeks of dietary supplementation (p < 0.05). Ventilatory parameters such as peak expiratory flow (PEF), forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) increased significantly after 4 weeks of dietary supplementation in group A (p < 0.05). Values of PEF, FVC, FEV1 and maximum expiratory flow at 25% of the forced vital capacity (v̇25) differed significantly between groups A and B prior to dietary supplementation. Serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol and phospholipid were significantly decreased by dietary supplementation in group A after 4 weeks. Serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, LDL cholesterol and phospholipid differed significantly between the two study groups prior to dietary supplementation. Serum levels of triglyceride and LDL cholesterol differed significantly between the two study groups after 4 weeks of dietary supplementation. Conclusions: Dietary supplementation with perilla seed oil in selected patients with asthma suppresses the generation of LTC4 and is associated with clinical features such as respiratory function and lipometabolism.

Low-Attenuation Areas of the Lungs on High-Resolution Computed Tomography in Asthma

To investigate the low-attenuation areas of the lungs (LAA) in asthma, we compared the mean lung density (MLD) and the LAA in 22 asthmatics (12 ex-smokers and 10 nonsmokers) and 13 patients with chronic obstructive pulmonary disease (COPD) by high-resolution computed tomography. The MLD and the relative area of the lung with attenuation values lower than −950 Hounsfield Units at full inspiration (inspiratory RA950) were significantly different in nonsmoking asthmatics compared to patients with COPD and asthmatics with a smoking history. The MLD and the RA950 correlated significantly with the FEV1 in all groups and with the DLCO in patients with COPD and asthmatics with a smoking history but not in nonsmoking asthmatics. We concluded that the LAA in asthmatics with a smoking history indicates the presence of emphysema, but in nonsmoking asthmatics it reflects hyperinflation and nonemphysematous expiratory airflow limitation rather than emphysematous lesions.

Effects of Long-Term Glucocorticoid Therapy on Bronchoalveolar Cells in Adult Patients with Bronchial Asthma

The effects of long-term glucocorticoid therapy on airway inflammation were examined in 84 asthma patients. The proportion of lymphocytes in bronchoalveolar lavage (BAL) fluid was significantly decreased in patients with steroid-dependent intractable asthma (SDIA) compared to results in non-SDIA patients, while BAL neutrophils were significantly increased in SDIA patients compared to results in non-SDIA patients. Regarding age, in patients under the age of 69 (except those between 30 and 39), BAL lymphocyte number was significantly decreased in SDIA compared with non-SDIA subjects, and in patients between 50 and 69, BAL neutrophils were significantly increased in SDIA compared with non-SDIA subjects. The number of BAL lymphocytes was significantly lower in patients with serum cortisol levels of less than 5.0 micrograms/dl than in those with levels of more than 5.1 micrograms/dl. BAL lymphocyte number was also significantly lower in patients who had received glucocorticoid therapy for more than 6 years than in those who had received such therapy for 2 years. These results show that long-term glucocorticoid therapy decreases the number of lymphocytes and increases neutrophil numbers in the airways.

Effects of Glucocorticoids on Humoral and Cellular Immunity and on Airway Inflammation in Patients with Steroid-Dependent Intractable Asthma

The effects of glucocorticoids on the proportion of lymphocytes in bronchoalveolar lavage (BAL) fluid in relation to humoral and cellular immunity were studied in 56 patients with steroid-dependent intractable asthma. To analyze the mechanism responsible for reduced numbers of BAL lymphocytes, we divided the subjects into 4 groups according to their BAL lymphocyte proportions: 0-4.9%, 5.0-9.9%, 10.0-14.9%, and 15.0-20.0%. Serum IgG levels and the peripheral lymphocyte count were significantly reduced in patients with a low proportion of BAL lymphocytes (less than 9.9%) than in those with more than 10% BAL lymphocytes. Delayed cutaneous reactivity to purified protein derivative was suppressed in patients with a low proportion of BAL lymphocytes (less than 4.9%). The mean proportion of BAL neutrophils tended to increase as the proportion of BAL lymphocytes decreased. These results show that the reduction in BAL lymphocytes produced by glucocorticoids is associated with suppressed humoral and cellular immunity, and that under such conditions the proportion of BAL neutrophils increases.

Oral Glucocorticoid-Induced Fall in Cortical Bone Volume and Density in Postmenopausal Asthmatic Patients

Abstract: Despite a deepening understanding of the influence of glucocorticoids (GC) on trabecular bone, little is known about GC-induced cortical bone loss. To elucidate the mechanism of GC-induced loss of cortical bone strength with particular reference to cortical bone loss, changes in cortical density, relative cortical volume, and the Strength Strain Index (SSI) based on biomechanical analyses of the geographic distribution of cortical bone material were measured. These parameters were compared, using peripheral quantitative computed tomography (pQCT), among the following age-matched groups: 68 postmenopausal asthmatic patients receiving high-dose oral GC in addition to inhaled GC (oral GC group), 68 postmenopausal asthmatic patients receiving only inhaled GC (inhaled GC group) and 69 postmenopausal controls without asthma or GC therapy (control group). Cortical bone mineral density (BMD) was measured, relative cortical volume was obtained by dividing the cortical area by the total bone area using pQCT (Stratec XCT960), and the Strength Strain Index (SSI) was calculated in the radius based on the density distribution around the axis. Spinal fracture was assessed on lateral radiographs. The number of vertebral fractures per patient correlated highly with cortical BMD, relative cortical volume and SSI values at the radius. The number of vertebral fractures per patient and the number of patients with fracture were similar between the control and inhaled GC group, both being significantly lower than those in the oral GC group. Total BMD, trabecular BMD, cortical BMD, relative cortical volume and SSI were similar between the first two, being significantly higher than in the last group. The slopes of cortical volume–density relationship, however, were identical among the three groups, indicating the persistence of cortical bone remodeling and a similar degree of calcification regardless of GC administration.

Different Roles of Histamine and Leukotriene C4 in the Airways Between Patients with Atopic and Nonatopic Asthma

The release of histamine and leukotriene C4 (LTC4) from bronchoalveolar lavage (BAL) cells and peripheral blood stimulated with Ca ionophore A23187 was compared between atopic and nonatopic asthma. The proportion of basophilic cells in BAL fluid was significantly higher in atopic than in nonatopic asthma (p < 0.01); however, no significant differences were present in the other BAL cells between the two asthma types. The concentration of histamine in BAL fluid was significantly higher in younger patients (20-59 years) with atopic than in nonatopic asthma (p < 0.01). In contrast, the concentration of LTC4 was significantly higher in nonatopic than in younger patients with atopic asthma (p < 0.01). The release of histamine from BAL cells (p < 0.001) and peripheral blood (p < 0.01) was significantly larger in younger patients with atopic than in nonatopic asthma. The generation of LTC4 by BAL cells was significantly larger in nonatopic than in younger (p < 0.01) and older patients with atopic asthma (60+ years) (p < 0.05). These results suggest that both histamine and LTC4 participate in the onset mechanism of atopic asthma, and only LTC4 participates in that of nonatopic asthma.

An Increased Level of Specific IgG4 Antibodies Against Candida albicans in Patients with Bronchial Asthma

Specific IgG4 antibodies against Candida albicans in sera were measured in 76 asthmatics. The increased level of specific IgG4 was found in cases 10-40 years old sensitive to house dust mite and/or Candida albicans, in cases with steroid-dependent intractable asthma (SDIA) and in elderly cases. The frequency of SDIA was the highest in cases 41 to 60 years old with higher frequency of increased IgG4 antibodies. The results show that specific IgG4 increases in relation to IgE-mediated immune response, long-term steroid therapy, and aging. All of these conditions may induce depressed cell-mediated immunity.