Suplatast tosilate, a new type of antiallergic agent, prevents the expression of airway hyperresponsiveness in guinea pigs

Suppression of the Th2 Pathway by Suplatast Tosilate in Patients with Perennial Nasal Allergies

Background

Suplatast tosilate (IPD-1151T), a selective Th2 cytokine inhibitor that suppresses the production of interleukin (IL)-4 and IL-5 in vitro or in animal models has been proved clinically effective for allergic rhinitis (AR). The aim of this study was to investigate changes in the Th2 pathway in human nasal mucosa after medication with IPD-1151T. Twelve patients were treated with IPD-1151T.

Methods

Twelve healthy volunteers served as normal controls. The following parameters were evaluated: (i) subjective nasal clinical symptoms, (ii) percentages of inflammatory cells (EG2, CD4, and CD8) by immunocytological staining, and (iii) levels of cytokines (IL-4, IL-5, IL-13, regulated on activation, normal T-cell expressed, and secreted [RANTES], and interferon [IFN] γ) by enzyme-linked immunosorbent assay.

Results

Nasal symptom scores significantly decreased after treatment. With respect to cell infiltration, a significant decrease was observed in the percentage of inflammatory cells (EG2 and CD4) and CD4/CD8 ratio. The levels of cytokines (IL-4, IL-5, IL-13, and IFN-γ) and the IL-5/IFN-γ ratio were significantly decreased, and the IL-4/IFN-γ ratio became not significantly different from that in normal subjects. In contrast, RANTES did not change significantly. The percentage of reduction in IL-5 correlated with that in eosinophil infiltration, whereas that in RANTES did not.

Conclusion

These results suggest that IPD-1151T can reduce the Th2 pathway.

Suplatast tosilate inhibits histamine signaling by direct and indirect down-regulation of histamine H1 receptor gene expression through suppression of histidine decarboxylase and IL-4 gene transcriptions

Allergic rhinitis (AR) is an inflammatory disorder typified by symptoms such as sneezing, congestion, and rhinorrhea. Histamine plays important roles in eliciting AR symptoms. Up-regulation of the histamine H(1) receptor (H1R) and histidine decarboxylase (HDC) mRNAs was observed in AR patients. Th2 cytokines are also involved in the pathogenesis of AR. We examined the effect of suplatast tosilate on nasal symptoms, and H1R, HDC, and IL-4 gene expression using toluene-2,4-diisocyanate (TDI)-sensitized rats and HeLa cells expressing endogenous H1R. Provocation with TDI increased nasal symptoms, HDC activity, the histamine content of nasal lavage fluid, and the expression of H1R, HDC, and IL-4 mRNAs in TDI-sensitized rats. Pretreatment with suplatast for 2 wk significantly suppressed TDI-induced nasal symptoms and elevation of H1R, HDC, and IL-4 mRNAs. Suplatast also suppressed HDC activity in the nasal mucosa and the histamine content of the nasal lavage fluid. Bilateral injection of IL-4 into the nasal cavity of normal rats up-regulated H1R mRNA, while intranasal application of histamine up-regulated IL-4 mRNA. Suplatast suppressed IL-4-induced up-regulation of H1R mRNA in HeLa cells. However, it did not inhibit histamine-induced H1R mRNA elevation. These results suggest that suplatast alleviates nasal symptoms by inhibiting histamine signaling in TDI-sensitized rats through the suppression of histamine- and IL-4-induced H1R gene expression by the inhibitions of HDC and IL-4 gene transcriptions, respectively.

Liquid chromatography/electrospray ionization mass spectrometry method for the determination of the active metabolite M-1 of suplatast tosilate in human plasma

A liquid chromatography/electrospray ionization mass spectrometry (LC/ESIMS) method for the determination of 4-(3-ethoxy-2-hydroxypropoxy) acrylanilide (M-1), the active metabolite of suplatast tosilate, in human plasma was established. Plasma samples were extracted with diethyl ether, separated on a C(18) column with a mobile phase of acetonitrile-10 mm ammonium acetate solution containing 0.1% formic acid (28:72, v/v) and detected by ESIMS. The method was linear over the concentration range 0.15-60.0 ng/mL. The lowest limit of quantification was 0.15 ng/mL. The intra- and inter-run relative standard deviations obtained from three validation runs were all less than 8.6%, and the intra- and inter-run relative errors were all less than 3.1%. The method was successfully applied for the evaluation of pharmacokinetic profiles of M-1 in healthy volunteers.

Effect of suplatast tosilate on goblet cell metaplasia in patients with asthma

BACKGROUND

Goblet cell metaplasia is a pathologic characteristic of asthma, associated with excess mucus secretion. Interleukin (IL)-4 and IL-13 plays an important role in mucus hypersecretion. Suplatast tosilate (suplatast), an antiallergic agent, is a Th2 cytokine inhibitor that suppresses the synthesis of IL-4, IL-5, IL-13, and eosinophilic airway inflammation.

OBJECTIVE

We examined the effects of suplatast on mucus production in bronchial biopsy specimens taken from asthmatic subjects.

METHODS

Oral suplatast 300 mg daily, or placebo was administered for 3 months in a double-blind, parallel-group study in 25 patients with asthma. Biopsy specimens were evaluated at before and after treatment for alcian blue/period acid-Schiff (AB/PAS), MUC5AC staining in bronchial epithelium and IL-4+, IL-13+ cells as well as inflammatory cells in lamina propria.

RESULTS

There were significant decreases in the percentage of AB/PAS (P < 0.01) and MUC5AC (P < 0.01) stained area in the suplatast group. These changes were accompanied by significant decreases in IL-4+ and IL-13+ cells in suplatast-treated subjects. Additionally, we have observed that the number of infiltrating eosinophils and CD4+ T cells significantly decreased.

CONCLUSIONS

These findings suggest that suplatast prevents goblet cell metaplasia through modulation of Th2 cytokine production and the recruitment of eosinophils and CD4+ T cells in the asthmatic airways.

Add-on effects of suplatast tosilate in bronchial asthma patients treated with inhaled corticosteroids

Th2 cytokines play an important role in the pathogenesis of asthma. In the present study, we investigated the effect of suplatast tosilate, a selective Th2 cytokine inhibitor, on asthma control, in terms of subjective symptoms and pulmonary function in patients treated with inhaled corticosteroids. Thirty-eight patients with bronchial asthma being treated with inhaled corticosteroids were given suplatast tosilate (100 mg three times daily) for 12 weeks, in a multicenter setting. During the study period, other medications were continued. Morning and evening peak expiratory flow, asthma symptoms, blood eosinophil count and serum IgE levels were monitored. Suplatast tosilate treatment was associated with a significant improvement in mean morning peak expiratory flow (from 295 L/min to 348 L/min, P < 0.01) and evening peak expiratory flow (from 313 L/min to 357 L/min, P < 0.01). The mean daily variation in peak expiratory flow was significantly reduced (from 11.6% to 7.3%, P < 0.01) by suplatast tosilate treatment. The greatest improvement in peak expiratory flow was observed in patients whose blood eosinophil counts were decreased by suplatast tosilate treatment. Treatment with suplatast tosilate improved pulmonary function in patients with bronchial asthma. Our results suggest the therapeutic effects observed may occur through suppression of eosinophilic inflammation.

Effects of suplatast tosilate on allergic eosinophilic airway inflammation in patients with mild asthma

BACKGROUND

Bronchial asthma is a chronic inflammatory disease characterized mainly by infiltration of the airway mucosa by various inflammatory cells, notably eosinophils. T(H)2-type cytokines are suggested to be deeply involved in the pathogenesis of asthma.

OBJECTIVE

We sought to determine the suppressive effects of suplatast tosilate, an inhibitor of T(H)2-type cytokines, on eosinophilic inflammation of the bronchial mucosa in patients with mild asthma.

METHODS

Airway hyperresponsiveness tests, pulmonary function tests, eosinophil measurements in induced sputum, and bronchial mucosa biopsies were performed before and after treatment with suplatast tosilate for 6 weeks in 15 patients with mild asthma and in 13 control patients with mild asthma not receiving suplatast tosilate. This study was performed as a case-controlled open study.

RESULTS

In the treatment group a significant improvement in the provocation concentration of histamine was observed (P <.05). Improvements in peak expiratory flow (P <.01) and in symptom score (P <.05) were also noted in the suplatast tosilate-treated group. Moreover, the average number of infiltrating eosinophils and EG2(+) cells significantly decreased (both P <.05), as did the ratios of eosinophils and EG2(+) cells in sputum (both P <.01). The average number of CD4(+) and CD25(+) T lymphocytes also decreased (both P <.05).

CONCLUSION

Suplatast tosilate appears to inhibit allergic airway inflammation mediated by T(H)2-type cytokine and to improve clinical symptoms in patients with mild asthma.

Effects of suplatast tosilate on cytokine profile of bronchoalveolar cells in allergic inflammation of the lung

OBJECTIVE

Suplatast tosilate is an anti-allergic agent that inhibits IgE antibody production. It appears to have an inhibitory effect on the production of Th2 cytokines (interleukin (IL)-4, IL-5) in vitro. In the present study, we investigated the effects of suplatast on eosinophil infiltration and cytokine mRNA expression in bronchoalveolar lavage (BAL) fluid in a Brown Norway (BN) rat model of bronchial asthma.

METHODOLOGY

Suplatast (50 mg/kg per day) was administered intraperitoneally for 15 consecutive days to 8-week-old male BN rats that had been actively sensitized to ovalbumin (OA) and alum and rats were challenged with OA aerosol to induce allergic bronchial inflammation. The control group was examined 48 h after antigen inhalation to measure the cell count and cell fraction in BAL fluid. Reverse transcription-polymerase chain reaction using primers for IL-4, IL-5, interferon (IFN)-gamma and beta-actin was used to semiquantitatively measure mRNA expression in BAL cells 24 h after antigen inhalation.

RESULTS

Suplatast was found to decrease the total cell count and the eosinophil count. The mean total cell count in BAL in the suplatast-treated group was 18.8 x 10(5) and the mean eosinophil count was 7.8 x 10(5) compared with 73.0 x 10(5) and 48.9 x 10(5), respectively, in the control group. Suplatast also suppressed expression of IL-4 and IL-5 mRNA in BAL cells. However, there were no significant changes in IFN-gamma expression.

CONCLUSIONS

Suplatast was found to have an inhibitory effect on eosinophil infiltration in a rat model of bronchial asthma. It also appeared to inhibit allergic inflammation by altering the cytokine profile.

Effect of suplatast tosilate on airway hyperresponsiveness and inflammation in asthma patients

Because eosinophilic airway inflammation is a characteristic of bronchial asthma, the treatment of such inflammation is important in the management of this disease. Suplatast tosilate is a novel anti-asthma drug that suppresses eosinophil proliferation and infiltration through selective inhibition of Th2 cytokine synthesis. We investigated the effect of oral suplatast tosilate therapy in patients with mild and moderate asthma. Twenty-eight asthma patients were randomized into two groups with or without suplatast tosilate treatment (100 mg t.i.d. for 28 days). We examined the blood eosinophil counts, eosinophilic cationic protein level, sputum eosinophil count, exhaled nitric oxide level, and airway responsiveness before and after treatment. In patients treated with suplatast tosilate, the eosinophil count in the blood and sputum was significantly decreased after treatment, while there was no such change in the patients without suplatast treatment. The exhaled nitric oxide level and airway responsiveness (measured using an Astograph) were also decreased after treatment with suplatast tosilate, while there were no significant changes in patients without suplatast tosilate. These results strongly suggest that oral administration of suplatast tosilate suppresses airway hyperresponsiveness in asthma patients by reducing eosinophilic inflammation in the airways.

Effects of suplatast tosilate, a new type of anti-allergic agent, on airway cough hypersensitivity induced by airway allergy in guinea-pigs

BACKGROUND

Cough receptor hypersensitivity is a fundamental feature of some conditions presenting with chronic non-productive cough. Suplatast tosilate, an anti-allergic agent, is a T helper (Th)2 cytokine inhibitor that inhibits the synthesis of interleukin (IL)-4, IL-5, immunoglobulin (Ig)E production, and local eosinophil accumulation.

OBJECTIVE

The purpose of this study was to investigate the effect of suplatast on antigen-induced airway cough hypersensitivity and eosinophil infiltration into the airway.

METHODS

Number of coughs elicited by inhalation of increasing concentrations of capsaicin (10-8, 10-6 and 10-4 M) was counted 24 h after an antigen challenge in conscious guinea-pigs and then bronchoalveolar lavage was performed. We investigated the effect of single (before antigen challenge or capsaicin provocation) or repetitive treatment with intraperitoneal suplatast at a dose of 10 or 30 mg/kg on antigen-induced cough hypersensitivity.

RESULTS

Twenty-four hours after antigen challenge, guinea-pigs developed an increase in cough receptor sensitivity to inhaled capsaicin and eosinophil infiltration in the airways. After a 2-week treatment with suplatast, but not after only a single treatment before antigen challenge or capsaicin provocation, the antigen-induced early phase bronchoconstriction, cough hypersensitivity, and airway eosinophilia were inhibited in a dose-dependent manner.

CONCLUSION

These results indicate that suplatast inhibits airway cough hypersensitivity underlying allergic eosinophilic inflammation.

Modification of eosinophil function by suplatast tosilate (IPD), a novel anti-allergic drug

Suplatast tosilate (IPD), a new dimethylsulfonium agent, is used therapeutically in allergic diseases. Suplatast has been reported to attenuate airway hyperresponsiveness in guinea pigs, human IgE synthesis, and murine peritoneal eosinophilia. However, the effect of suplatast on human eosinophils is not known. In this study, we examined the effects of suplatast in human eosinophils on platelet activating factor (PAF, 1 microM)-induced chemotaxis by the blind well chamber technique, eosinophil adhesion to TNF-alpha (10 ng/ml) or IL-4 (10 ng/ml)-stimulated human umbilical vein endothelial cells (HUVECs), and expression of very late antigen-4 (VLA-4) on eosinophils and vascular cell adhesion molecule-1 (VCAM-1) on HUVECs by flow cytometry. Suplatast suppressed IL-4-induced eosinophil adhesion to HUVECs in a dose-dependent manner. Eosinophils from the normal subjects did not express VLA-4. However, there was a significant increase (P < 0.01) in the basal expression of VLA-4 in allergic patients. PAF or IL-4 did not enhance VLA-4 expression on eosinophils, and there was no significant effect of suplatast on VLA-4 expression in allergic patients. Suplatast did not affect TNF-alpha-induced VCAM-1 expression. Interestingly, suplatast significantly suppressed IL-4 induced VCAM-1 expression on HUVECs and PAF-induced eosinophil chemotaxis. These data suggest that suplatast may modify eosinophil participation in airway inflammation by attenuating inflammatory mediators-induced chemotaxis and adhesion to endothelial cells, and thus might be useful in the treatment of bronchial asthma.

Effects of suplatast tosilate on airway inflammation and airway hyperresponsiveness

Suplatast tosilate (IPD) is a Th2 cytokine inhibitor that lowers the titer of the IgE antibody through specific inhibition of the production of IL (interleukin)-4 and IL-5 by T cells and inhibits tissue infiltration by eosinophils. In this clinical trial, suplatast tosilate (300 mg/day) was administered orally for 4 weeks to 25 patients (13 patients with atopic asthma, 12 patients with nonatopic asthma) whose bronchial asthma was staged in step 1 or step 2 according to the Guidelines for Prevention and Management of Bronchial Asthma, 1998. Before and after administration, the parameters of airway inflammation, that is, peripheral blood eosinophils count, serum level of eosinophil cationic protein (ECP), ECP level in induced sputum, airway hyperresponsiveness (Dmin), and morning peak expiratory flow (PEF), were measured. The peripheral blood eosinophil count, serum level of ECP, and ECP level in induced sputum decreased significantly. Of these parameters, the ECP level in induced sputum was the most sensitive. Furthermore, suplatast tosilate significantly inhibited Dmin. These results were especially significant in patients with atopic asthma. Suplatast tosilate was considered to have inhibited airway eosinophilic inflammation through decreases in peripheral blood eosinophils counts and in ECP levels in induced sputum, which resulted in inhibition of airway hyperresponsiveness.

Suplatast tosilate inhibits goblet-cell metaplasia of airway epithelium in sensitized mice

BACKGROUND

IL-4 and IL-13 play a putative role in mucus hypersecretion in asthma. Suplatast tosilate prevents the synthesis of T(H2) cytokines.

OBJECTIVE

Because suplatast tosilate inhibits T(H2) cytokines but does not inhibits IFN-gamma production, we examined the effect of suplatast on IL-4- or IL-13- and ovalbumin (OVA)-induced mucin synthesis in NCI-H292 cells in vitro and in bronchi of pathogen-free BALB/c mice in vivo.

METHODS

In vitro, NCI-H292 cells were preincubated with suplatast tosilate (0.1-100 microgram/mL) 1 hour before adding human recombinant IL-4 (10 ng/mL). In vivo, mouse recombinant IL-4 or IL-13 (250 ng per/mouse) was instilled intranasally in mice pretreated with suplatast tosilate (50 mg.kg(-1).d(-1)). Mucous glycoconjugates were stained with Alcian blue (AB)/periodic acid-Schiff (PAS) stain. To evaluate effects of suplatast tosilate on goblet-cell metaplasia in OVA-sensitized mice, animals were pretreated with suplatast tosilate (1-50 mg.kg(-1).d(-1)) intragastrically. IL-4 and IL-13 were measured, and allergic inflammatory cells were analyzed in bronchoalveolar lavage fluid of OVA-sensitized mice.

RESULTS

Pretreatment with suplastast did not prevent IL-4- or IL-13-induced increase in mucous glycoconjugate production in NCI-H292 cells or in mice. OVA sensitization increased AB/PAS-stained area of the epithelium (48.1% +/- 2.4%, P <.01 compared with control mice). Suplatast tosilate inhibited OVA-induced goblet-cell metaplasia in airway epithelium in a dose-dependent fashion; 50 mg.kg(-1).d(-1) decreased the AB/PAS area to 22.7% +/- 2.7% (P <.05 compared with OVA sensitization alone). Pretreatment with suplatast tosilate also prevented OVA-induced increase in IL-4 and IL-13 levels and decreased the number of lymphocytes and eosinophils in bronchoalveolar lavage fluid (P <.05 compared with values of mice given OVA alone).

CONCLUSION

These results indicate that suplatast tosilate prevents allergen-induced goblet-cell metaplasia and the recruitment of eosinophils and lymphocytes into the airways. These results suggest that this effect is due to the prevention of the production of T(H2) cytokines in airways.

Suplatast tosilate inhibits late response and airway inflammation in sensitized guinea pigs

The effect of suplatast tosilate, which has been proven to inhibit T-cell synthesis of IL-4 and IL-5, on the response to antigen inhalation challenge was investigated in sensitized guinea pigs. The animals were given an oral dose of 30 or 100 mg/kg of suplatast or vehicle (distilled water) daily for 1 wk before antigen challenge. Measurement of pulmonary resistance for 6 h was followed by bronchoalveolar lavage and lung fixation. After antigen challenge, all guinea pigs in the vehicle group displayed dual-phase airway obstruction and accumulation of eosinophils and lymphocytes in the airways. After 1 wk of treatment with the high dose of suplatast, the late asthmatic response and the recruitment of eosinophils and lymphocytes into the airways were significantly inhibited, but the early asthmatic response was not affected. In situ hybridization revealed that challenge-induced increases in IL-5 mRNA-positive cells in lung tissue were significantly inhibited after treatment. Thus, suplatast inhibited airway obstruction in the late phase by specifically inhibiting the inflammatory process after mast cell degranulation.