Kohei Koide

Plasma levels of leukotriene E4 during clinical course of chronic obstructive pulmonary disease

We investigated the relationship between circulating leukotriene E4 (LTE4) and chronic obstructive pulmonary disease (COPD) by measuring plasma levels of leukotriene E4 in patients with COPD and 10 normal controls. We also investigated the relationship between LTE4 levels and FEV1 and PaO2. Leukotriene E4 was measured by high performance liquid chromatography (HPLC) and radioimmunoassay. The mean leukotriene E4 level in patients with COPD during remission, during acute exacerbation before and after prednisolone treatment were 16.8[4.02], 41.7[21.9], and 19.5[3.78] pg/ml (mean[SD]), respectively. In contrast, the mean leukotriene E4 level of 10 normal controls was 11.8[4.49] pg/ml. Thus, the mean LTE4 level during an acute exacerbation of COPD was significantly lower in patients after prednisolone treatment than in patients before prednisolone treatment. The mean LTE4 level in patients after prednisolone treatment did not significantly differ from that in patients during remission and in normal controls (Scheffe F-test, P < 0.05) (Fig. 1). Mean FEV1 (% predict) values were 51.4[9.02] (mean[SD]), 38.0[4.82], and 44.2[4.48] on the three occasions, respectively; corresponding mean PaO2 values (mmHg) were 84.0[5.01] (mean[SD]), 61.3[1.66], and 80.6[5.30], respectively. Leukotriene E4 levels were significantly correlated with PaO2 and relatively with FEV1 in the patients during acute exacerbation before prednisolone treatment. Thus, we suggest that leukotriene E4 levels in arterial blood reflect the severity of COPD lung and oral prednisolone reduces the plasma levels of leukotriene E4 in patients with COPD.

Effect of azelastine hydrochloride on release and production of platelet activating factor in human neutrophils

Effect of azelastine hydrochloride (azelastine) on release and production of platelet-activating factor (PAF) in neutrophils obtained from asthmatic and non-asthmatic patients was investigated. Neutrophils were preincubated with or without azelastine and stimulated with f-Met-Leu-Phe (fMLP, 10 microM) for 15 min. PAF-like activity was detected by aggregation of washed guinea pig platelets. PAF-like activity released from asthmatic neutrophils without preincubation of azelastine was 5.67[0.89] (mean[SD], ng/10(7) cells) in supernatants and 21.8[0.76] in cell pellets. After preincubation with 10(-8), 10(-6), and 10(-4) M of azelastine, PAF-like activity reduced to 5.96[0.97] (mean[SD], ng/10(7) cells), 3.49[0.63], and 1.89[0.09] (n = 15) in the supernatants, and 20.7[0.97], 13.9[0.29], and 8.91 [0.99] (n = 15) in the cell pellets, respectively. PAF-like activity in non-asthmatic neutrophils without preincubation of azelastine was 4.67[0.19] (mean[SD], ng/10(7) cells) in supernatants and 18.5[0.34] in cell pellets. After preincubation with 10(-8), 10(-6), and 10(-4) M of azelastine, PAF-like activity reduced to 4.39[0.51] (mean[SD], ng/10(7) cells), 2.77[0.22], and 1.75[0.07] (n = 15) in the supernatants, and 17.9[0.54], 10.8[0.25], and 5.97 [0.59] (n = 15) in the cell pellets, respectively. Our results showed that preincubation with azelastine caused a dose-dependent inhibition of intra and extracellular PAF-like activity from asthmatic and non-asthmatic neutrophils in the same manner.

Prednisolone inhibits synthesis of 5-H(P)ETE in eosinophils from asthmatic patients during a wheezing attack but not during remission

To estimate the effect of prednisolone on 5-lipoxygenase activity in eosinophils obtained from asthmatic patients, cytosolic levels of 5-H(P)ETE and Ca2+ were measured in the eosinophils which were exposed to prednisolone in vitro and in vivo. The mean level of 5-H(P)ETE during a wheezing attack was significantly lower in the patients who had received intravenous prednisolone (500 mg/day). Incubation with prednisolone in vitro caused a dose-dependent decrease in the cytosolic levels of 5-H(P)ETE and Ca2+ in eosinophils obtained during the wheezing attack, but not in the eosinophils obtained from during remission. Results suggest that prednisolone inhibits the level of 5-H(P)ETE in the eosinophil cytosols of asthmatic patients during a wheezing attack, probably by inhibition of 5-lipoxygenase activity which is involved in the reduction of the influx of Ca2+.

Release of platelet-activating factor from stimulated asthmatic eosinophils

Abstract We examined platelet-activating factor (PAF)-like activity in eosinophils obtained from asthmatic and nonasthmatic patients. PAF-like activity was detected by aggregation of washed guinea pig platelets. Eosinophils from asthmatic patients stimulated with C5a (a human complement factor), N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), or calcium ionophore A23187 had a mean activity of 8.86 ± 1.99 ng/10 6 cells in the supernatants and 20.34 ± 7.11 ng/10 6 cells in the cell pellets, 10.75 ± 0.78 and 25.44 ± 5.23, and 12.89 ± 1.74 and 36.67 ± 6.43, respectively. Mean PAF-like activities in eosinophils from nonasthmatic patients stimulated with C5a, fMLP, or A23187 were 5.91 ± 0.23 ng/10 6 cells in the supernatants and 9.12± 1.95 ng/10 6 cells in the cell pellets, 6.99 ± 0.93 and 7.09 ± 1.11, and 7.22 ± 1.42 and 9.78 ± 2.03, respectively. With no stimulation, mean PAF-like activities in both eosinophil populations were under the detection limit in the supernatants and in the cell pellets. PAF-like activity was greater in asthmatic eosinophils than in nonasthmatic eosinophils after stimulation with C5a, fMLP, or A23187, suggesting that asthmatic eosinophils contribute to the development of bronchial asthma by inducing more PAF-like activity.

Comparison of Platelet-activating factor activity in neutrophils from healthy donors and patients with bronchial asthma

Abstract This study was designed to compare platelet-activating factor (PAF)-like activity in neutrophils obtained from patients with bronchial asthma with neutrophils obtained from healthy donors. The neutrophils were stimulated with 10 μM formly-methionyleucylphenylalanine for 15 minutes. PAF-like activity was detected by aggregation using washed guinea pig platelets. PAF-like activity released from neutrophils of patients with asthma was 23 ± 10.7 %/10 6 cells (mean ± SD) in the supernatants and 90 ± 8.8 %/10 6 cells in the cells. PAF-like activity released from neutrophils of healthy donors was 9 ± 4.9 %/10 6 cells in the supernatants and 27 ± 7.3 %/10 6 cells in the cells. Results of this study show that PAF-like activity is greater in neutrophils of patients with asthma than in neutrophils of healthy donors, suggesting that neutrophils of patients with bronchial asthma release more PAF and are involved in development of the disease.