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T cells are the principal source of interleukin-5 mRNA in allergen-induced rhinitis.

We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of subjects with allergic rhinitis. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies from six patients, before and 24 h after local allergen provocation with grass pollen. Immunocytochemistry (APAAP) was followed by in situ hybridization on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, and major basic protein (MBP) were used to identify T cells, mast cells, and eosinophils, respectively. Hybridization studies were performed using a Digoxigenin-labeled IL-5 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3- indoly phosphate (BCIP) served as chromogens to detect hybridized IL-5 mRNA signals. The majority of IL-5 mRNA+ cells were CD3+ (83.2%), whereas the remainder were either tryptase+ (11.3%) or MBP+ (5.4%). In contrast, only a few IL-5 mRNA+ cells were observed in nasal biopsies before challenge, all of which were co-localized to CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-5 transcripts in the nasal mucosa 24 h after allergen-induced late-phase nasal responses.

Adult↗

Dog mastocytoma cells secrete a 92-kD gelatinase activated extracellularly by mast cell chymase.

Gelatinolytic metalloproteinases implicated in connective tissue remodeling and tumor invasion are secreted from several types of cells in the form of inactive zymogens. In this report, characterization of gelatinase activity secreted by the BR line of dog mastocytoma cells reveals a phorbol-inducible, approximately 92-kD, Ca2+ - and Zn2+ -dependent proenzyme cleaved over time to smaller, active forms. Incubation of cells with the general serine protease inhibitor, PMSF, prevented proenzyme cleavage and permitted its purification free of activation products. The NH2-terminal 13 amino acids of the purified mastocytoma progelatinase are 50-67% identical to those of human, mouse, and rabbit 92-kD progelatinase (gelatinase B; matrix metalloproteinase-9). Degranulation of mastocytoma cells using ionophore A23187 greatly accelerated proenzyme cleavage, suggesting that a serine protease present in secretory granules hydrolyzed the progelatinase to active fragments. To identify the activating protease, cells were coincubated with ionophore and a panel of selective serine protease inhibitors. Soybean trypsin inhibitor and succinyl-L-Ala-Ala-Pro-Phe-chloromethylketone, which inhibit mast cell chymase, prevented progelatinase activation. Inhibitors of tryptase and dog mast cell protease (dMCP)-3, i.e., aprotinin or bis(5-amidino-2-benzimidazolyl) methane (BABIM), did not. In further experiments using highly purified enzymes, mastocytoma cell chymase activated 92-kD progelatinase in the absence of other enzymes or cofactors; tryptase and dMCP-3, however, had no effect. These data demonstrate that dog mastocytoma cells secrete a metalloproteinase related to progelatinase B that is directly activated outside of the cell by exocytosed chymase, and provide the first demonstration of a cell that activates a matrix metalloproteinase it secretes by cosecreting an activating enzyme. In mastocytomas, this pathway may facilitate tumor invasion of surrounding tissues, and in normal mast cells, it could play a role in tissue remodeling and repair.

Amino Acid Sequence↗

Immunological characteristics of patients infected with common intestinal helminths: results of a study based on reverse-transcriptase PCR.

To determine whether common helminth infections could modify the intestinal immunopathological status of the host, the expression in the human duodenal mucosa of cytokines, eosinophil- and mast-cell-specific molecules and monosaccharide transporters of the glucose-transporter (GLUT) family was explored. The 31 subjects were all patients at the gastro-intestinal disease unit of Nongkhai Hospital, Thailand. Four of the 10 patients who presented with eosinophilia (> or = 6.0% of their leucocytes were eosinophils), and five of the other 21 patients, had intestinal infections with helminths when they presented or within the previous 3 months. Studies based on semi-quantitative, reverse-transcriptase PCR revealed that the interleukin-5/interferon-gamma ratio was significantly higher in the noneosinophilic, helminth-infected patients than in the non-eosinophilic, uninfected patients, whereas the IgE receptor type I (Fc epsilon RI)/mast-cell tryptase ratio was significantly higher in the eosinophilic, helminth-infected patients than in the eosinophilic, uninfected patients. Expression of Charcot-Leyden-crystal protein, GLUT-1 and GLUT-5, however, showed no significant inter-group differences. Principal-components analysis of the data on eosinophils, interleukin-5, interferon-gamma, Fc epsilon RI and mast-cell tryptase revealed that one principal component could discriminate the patients who had helminth infection from the non-eosinophilic, uninfected patients, but not from the eosinophilic, uninfected patients. These results indicate that, whatever the intestinal pathology, patients infected with common intestinal helminths tend to develop a mucosal immunological response of the Th2 type.

Adult↗

Molecular remission and reversal of myelofibrosis in response to imatinib mesylate treatment in patients with the myeloproliferative variant of hypereosinophilic syndrome.

We recently described a subset of patients with a myeloproliferative variant of hypereosinophilic syndrome (MHES) characterized by elevated serum tryptase levels, increased atypical mast cells in the bone marrow, tissue fibrosis, and the presence of the fusion tyrosine kinase, FIP1L1-PDGFRalpha, which is a therapeutic target of imatinib mesylate. Seven patients with MHES were treated with imatinib mesylate (300-400 mg daily). Clinical improvement and resolution of eosinophilia was observed in all patients, although cardiac dysfunction, when present, was not altered by therapy. Reversal of bone marrow pathology, including increased cellularity, the presence of spindle-shaped mast cells, and myelofibrosis, was evident in all patients at 4 to 8 weeks following initiation of therapy. This was accompanied by a decrease in activated eosinophils and mast cells in the peripheral blood and bone marrow, respectively. Serum tryptase levels declined rapidly to normal levels in all patients and remained in the normal range throughout therapy. Molecular remission, with disappearance of detectable FIP1L1/PDGFRA (F/P) transcripts, was achieved in 5 of 6 patients tested. The lack of reversal of cardiac abnormalities and persistence of the F/P mutation in some patients suggests that early intervention with higher doses of imatinib mesylate may be desirable in the treatment of patients with MHES.

Adult↗

Low- and high-dose fluticasone propionate in asthma; effects during and after treatment.

The dose dependency of the effects of inhaled corticosteroids on markers of asthmatic airway inflammation have not been well studied. There is a need to study the dose/response effects on this inflammation. In order to determine the dose/response effects of fluticasone propionate (FP), 24 asthmatic subjects were randomized to low- (100 microg x day(-1)) or high-dose (1,000 microg x day(-1)) FP for six weeks followed by placebo for 3 weeks. During treatment, the median increase in forced expiratory volume in one second (FEV1)was 12% in the high-dose group (p<0.05) and 10% in the low-dose group (p<0.05) (p>0.05 between groups); the median decrease in the percentage of sputum eosinophils was 93% in the high-dose group (p<0.05) and 46% in the low-dose group (p<0.05) (p>0.05 between groups). Symptoms, salbutamol use, morning peak flow, provocative concentration of methacholine causing a 20% fall in FEV1 (PC20), sputum eosinophil cationic protein concentration and tryptase activity improved significantly in both groups (p<0.05), but only the improvement in salbutamol use was greater in the high-dose group (p<0.05). During the run-out, the improvements in FEV1 and PC20 were rapidly reversed in both groups, but the improvements in peak flow and tryptase activity persisted; the improvement in sputum eosinophil concentration persisted only in the high-dose group (p<0.05). It was concluded that dose/response effects for FP are not easily demonstrable because low-dose FP is quite effective. For most outcomes, the effects of high- and low-dose FP are relatively short-lived after treatment is stopped. This finding raises questions about the extent to which inhaled corticosteroids are disease-modifying in asthma.

Administration, Inhalation↗

Airway inflammation during stable and acutely exacerbated chronic obstructive pulmonary disease.

The aim of this study was to clarify the mechanism of increased airway inflammation during an acute exacerbation. A total of 68 chronic obstructive pulmonary disease patients in a stable phase were enrolled and followed-up for 2-3 yrs. Inflammatory cells were analysed, and interleukin (IL)-8, neutrophil elastase, eotaxin, tryptase and RANTES (regulated on activation, normal T-cell expressed and secreted) were measured in sputum, both in a stable phase and during acute exacerbation. Out of 68 patients, 30 (unstable group) developed an acute exacerbation and expectorated adequate sputum during exacerbation. Thirty-two patients (stable group) did not develop any exacerbation for 2-3 yrs. The number of neutrophils, lymphocytes and eosinophils, and the levels of IL-8, eosinophil cationic protein (ECP), eotaxin and tryptase in sputum obtained from patients in both groups during the stable phase were significantly higher than those from healthy nonsmokers. There were no significant differences in cell analysis and biomarkers between the two groups, but patients in the unstable group showed more severe airflow limitation. In the unstable group, total cells, lymphocytes, neutrophils and eosinophils, and IL-8, neutrophil elastase, ECP and RANTES levels were significantly increased during an exacerbation from values in a stable phase. These findings suggest that exacerbation of chronic obstructive pulmonary disease may associate with additional increases in airway inflammation mediated by neutrophils, lymphocytes, eosinophils, interleukin-8 and RANTES.

Acute Disease↗

Bronchoalveolar lavage findings in patients with chronic nonproductive cough.

Mast cells and eosinophils may play a role in the pathophysiology of chronic cough in nonasthmatics. It is unknown, however, whether degranulation of these cells occurs in the airways of such patients. Thirty-five nonsmoking patients referred with a chronic nonproductive cough (mean cough duration 76.2 months) were evaluated using a comprehensive diagnostic protocol. Bronchoalveolar lavage (BAL) cell differentials and BAL histamine, tryptase and eosinophilic cationic protein (ECP) concentrations were determined. Ten nonsmoking healthy volunteers served as controls. Diagnostic subgroups were identified: eight postnasal drip syndrome (PNDS), seven cough variant asthma (CVA), seven gastro-esophageal reflux (GOR), seven dual aetiology and six idiopathic. Nonasthmatic coughers (NAC) were characterized as those patients without bronchial hyperresponsiveness on histamine challenge and whose cough had either responded to therapy for PNDS or GOR or failed to improve with antiasthma therapy. There was a significant increase in both eosinophil and mast cell numbers (p<0.05) and in histamine levels (p = 0.027) when NAC patients were compared with controls. Tryptase and ECP levels were elevated in 7 of 23 and 6 of 23 NAC patients, respectively. In conclusion, airway inflammatory cell numbers are not only increased but also activated, suggesting an important role for airways inflammation in the pathophysiology of chronic nonproductive cough.

Adult↗

Mast cell activation and its relation to proinflammatory cytokine production in the rheumatoid lesion.

INTRODUCTION: Increased numbers of mast cells (MCs) are found in the synovial tissues and fluids of patients with rheumatoid arthritis (RA), and at sites of cartilage erosion. MC activation has been reported for a significant proportion of rheumatoid specimens. Because the MC contains potent mediators, including histamine, heparin, proteinases, leukotrienes and multifunctional cytokines, its potential contributions to the processes of inflammation and matrix degradation have recently become evident. Proinflammatory cytokines are important mediators of inflammation, immunity, proteolysis, cell recruitment and proliferation. Tumour necrosis factor (TNF) reportedly plays a pivotal role in the pathogenesis o RA, especially its ability to regulate interleukin (IL)-1beta expression, this being important for the induction of prostanoid and matrix metalloproteinase production by synovial fibroblasts and chondrocytes. IL-15 has been assigned numerous biological effects and has been assigned numerous biological effects and has been implicated as an important factor in TNF-alpha expression by monocyte/macrophages. Some in vitro studies have placed IL-15 upstream from TNF-alpha in the cytokine cascade, suggesting an interdependence between TNF, IL-1 and IL-15 for the promotion of proinflammatory cytokine expression in the rheumatoid joint. AIMS: To examine the in situ relationships of TNF-alpha, IL-1beta and IL-15 in relation to MC activation in rheumatoid tissues by use of immunolocalization techniques; and to compare quantitatively the proinflammatory cytokine production by specific cell cultures and rheumatoid synovial explants with and without exposure to a MC secretagogue. MATERIALS AND METHODS: Samples of rheumatoid synovial tissue and cartilage-pannus junction were obtained from patients (n=15) with classic late-stage RA. Tissue sections were immunostained for MC (tryptase) and the proinflammatory cytokines IL-1, TNF-alpha and IL-15. Rheumatoid synovial tissue explants were cultured in Dulbecco's modified Eagles medium (DMEM) containing either the MC secretagogue rabbit antihuman immunoglobulin (Ig)E, or control rabbit IgG. Primary rheumatoid synovial cell cultures, human articular chondrocytes, synovial fibroblasts and synovial macrophages were prepared as described in the full article. Conditioned culture media from these cultures were collected and assayed for IL-1beta, TNF-alpha and IL-15 using enzyme-linked immunosorbent assay methodology. RESULTS: Immunohistological studies of rheumatoid synovial tissues have demonstrated local concentrations of MCs in most specimens of the rheumatoid lesion. Sites of MC activation were associated with localized oedema, and TNF-alpha, IL-1alpha and IL-1beta production by a proportion of mononuclear inflammatory cells. By contrast, no evidence was found for IL-15 production in tissue sites containing either intact or activated MCs, and IL-15 expression, when observed, bore no relation to tissue sites where TNF-alpha and IL-1beta were evident. The immunodetection of IL-15 was restricted to microfocal sites and was not typical of most junctional specimens, but was associated with a proportion of articular chondrocytes in a minority of junctional specimens. MC activation within synovial explant cultures was induced by the addition of polyclonal antibody to human IgE. MC activation significantly reduced the levels of TNF-alpha and IL-1beta released into the medium, this representing approximately 33% of control values. By contrast, MC activation had little effect of the levels of IL-15 released into the culture medium, the average value being very low in relation to the release of TNF-alpha and IL-1beta. Thus, induced MC activation brings about changes in the amounts of released tryptase, TNF-alpha and IL-1beta, but not of IL-15. Four preparations of primary rheumatoid synovial cell cultures produced more IL-1beta than TNF-alpha, with only modest values for IL-15 production, indicating that all three cytokines are produced and released as free ligands by these cultures. Of specific cell types that produced IL-15 in vitro, macrophages produced more than fibroblasts, which in turn produced more than chondrocytes. This demonstrates that all three cell types have the potential to produce IL-15 in situ. DISCUSSION: The biological consequences of MC activation in vivo are extremely complex, and in all probability relate to the release of various combinations of soluble and granular factors, as well as to the expression of appropriate receptors by neighbouring cells. The subsequent synthesis and release of cytokines such as TNF-alpha and IL-1 may well follow at specific stages after activation, or may be an induced cytokine response by adjacent macrophagic or fibroblastic cells. However, because no IL-15 was detectable either in or around activated or intact MCs, and the induced MC activation explant study showed no change in IL-15 production, it seems unlikely that the expression of this cytokine is regulated by MCs. The immunohistochemistry (IHC) demonstration of IL-15 at sites of cartilage erosion, and especially by some chondrocytes of articular cartilage, showed no spatial relationship with either T cells or neutrophils, and suggests other functional properties in these locations. The lack of evidence for an in situ association of IL-15 with TNF and IL-1 does not support a role for IL-15 in a proinflammatory cytokine 'cascade', as proposed by other in vitro experiments. We believe that sufficient evidence is available, however, to suggest that MC activation makes a significant contribution to the pathophysiological processes of the rheumatoid lesion.

Arthritis, Rheumatoid↗

Mast cell infiltration associated with tubulointerstitial fibrosis in chronic Aristolochic Acid Nephropathy.

Aristolochic Acid Nephropathy (AAN) is regarded as a kind of toxic nephropathy caused by the formation of DNA- aristolochic acid adducts in renal parenchymal cells. However, the underlying mechanisms driving the progression of renal interstitial fibrosis in AAN still remains unclear. This study aims to elucidate the role of some immunological factors, especially mast cells (MCs), in the pathogenesis of AAN. Sixteen patients with AAN were enrolled in this study, including five acute and 11 chronic AAN. Monoclonal antibodies against human tryptase, alpha smooth muscle actin (alpha-SMA), and CD68 were applied on serial sections, which were further counterstained with Periodic Acid-Schiff. It was found that massive tryptase-positive MCs were observed in the fibrotic areas in chronic AAN, especially around thickened tubular basement membranes where myofibroblasts accumulated too. In contrast, MCs infiltrated to a less extent in acute AAN, and were barely found in normal control kidneys. In chronic AAN, the number of MCs in the tubulointerstitium was positively correlated with the degree of renal fibrosis (r=0.64, P <0.05), but not with serum creatinine levels. Meanwhile, the recruitment of MCs into the renal interstitium is accompanied with local proliferation of myofibroblasts. Macrophages were not abundant, neither in acute nor in chronic AAN. Our findings show for the first time that mast cell infiltration seems to be associated with the progression of fibrosis in the renal tubulointerstitium in chronic AAN.

Acute Disease↗

MMP-1 activation by serine proteases and MMP-10 induces human capillary tubular network collapse and regression in 3D collagen matrices.

Previous work has shown that endothelial cell (EC)-derived matrix metalloproteinases (MMPs) regulate regression of capillary tubes in vitro in a plasmin- and MMP-1 dependent manner. Here we report that a number of serine proteases can activate MMP-1 and cause capillary tube regression; namely plasma kallikrein, trypsin, neutrophil elastase, cathepsin G, tryptase and chymase. Plasma prekallikrein failed to induce regression without coactivators such as high molecular weight kininogen (HMWK) or coagulation Factor XII. The addition of trypsin, the neutrophil serine proteases (neutrophil elastase and cathepsin G) and the mast cell serine proteases (tryptase and chymase) each caused MMP-1 activation and collagen type I proteolysis, capillary tubular network collapse, regression and EC apoptosis. Capillary tube collapse is accompanied by collagen gel contraction, which is strongly related to the wound contraction that occurs during regression of granulation tissue in vivo. We also report that proMMP-10 protein expression is markedly induced in ECs undergoing capillary tube morphogenesis. Addition of each of the serine proteases described above led to activation of proMMP-10, which also correlated with MMP-1 activation and capillary tube regression. Treatment of ECs with MMP-1 or MMP-10 siRNA markedly delayed capillary tube regression, whereas gelatinase A (MMP-2), gelatinase B (MMP-9) and stromelysin-1 (MMP-3) siRNA-treated cells behaved in a similar manner to controls and regressed normally. Increased expression of MMP-1 or MMP-10 in ECs using recombinant adenoviral delivery markedly accelerated serine protease-induced capillary tube regression. ECs expressing increased levels of MMP-10 activated MMP-1 to a greater degree than control ECs. Thus, MMP-10-induced activation of MMP-1 correlated with tube regression and gel contraction. In summary, our work demonstrates that MMP-1 zymogen activation is mediated by multiple serine proteases and MMP-10, and that these events are central to EC-mediated collagen degradation and capillary tube regression in 3D collagen matrices.

Capillaries↗

Two kinds of neutral serine proteinases in salted muscle of anchovy, Engraulis japonica.

Two kinds of proteinases, type-I and type-II, were purified or partially purified from salted muscle of anchovy, Engraulis japonica. Mol. wts. of type-I and type-II proteinases were estimated to 25,000 and 37,000, respectively, on electrophoretic analysis. Both proteinases strongly hydrolyzed synthetic tri or tetrapeptide substrates specific to trypsin, alpha-thrombin, and an activated protein C, while they hardly hydrolyzed Arg-MCA and benzoyl Arg-MCA derivatives. The proteinases were inhibited by common trypsin inhibitors. Optimal pH for the proteinase activities were pH 6.8 (type-I) and pH 7.0 to 7.5 (type-II), and the proteinases showed the highest activities at 45 degrees C (type-I) and 50 degrees C (type-II). The N-terminal amino acid sequence of type-I proteinase, 1I-2V-3G-4G ... (29 residues were identified), was significantly similar to sequences of trypsins and tryptases. Based on these findings, both proteinases were presumed to be kinds of tryptases in E. japonica muscle.

Amino Acid Sequence↗

Refractory anaphylactic shock associated with ketoconazole treatment.

OBJECTIVE: To report a rare but severe reaction of refractory anaphylactic shock with ketoconazole treatment-associated hypotensive episodes in an elderly patient. CASE SUMMARY: A 72-year-old woman received antifungal therapy for her almost completely occluded cornea infected with Candida albicans. She was initially prescribed oral ketoconazole 200 mg twice daily. She developed hypotension over the first 2 days of therapy (BP 136/82 mm Hg at baseline; 90/50 mm Hg on day 2). Severe hypotension (BP 90/49 mm Hg) unresponsive to fluid therapy or high-dose dopamine developed on day 4 of therapy. An invasive Swan-Ganz catheterization study showed a very low level of peripheral vascular resistance with high cardiac output index without clinical signs of infection. When laboratory tests showed a high level of plasma tryptase, anaphylactic redistribution shock was diagnosed. Her vital signs became more stable after treatment with hydrocortisone and epinephrine infusion. She was discharged in good condition after 24 hours of observation. DISCUSSION: As of December 2004, refractory anaphylactic shock resulting from ketoconazole use had not been reported. The events of hypotension were strongly associated with the intake of ketoconazole. The hemodynamic results obtained with Swan-Ganz catheterization were compatible with anaphylactic shock. The Naranjo probability scale showed a probable association of the adverse event with ketoconazole. CONCLUSIONS: Ketoconazole may cause severe anaphylactic shock even when taken orally. Invasive catheterization and elevated tryptase levels can provide important information in the management of anaphylactic shock.

Aged↗

T-cell lymphoma with eosinophilic infiltration involving the intestinal tract in 11 dogs.

Among the intestinal tumors of hematopoietic cell origin, lymphoma is the most common in the dog. Herein, we characterized the clinical and pathologic features of 11 dogs (average age, 10.6 +/- 2.5 years) with T-cell lymphoma of the intestinal tract with eosinophil infiltrates. No sex predominance was apparent. All had localized tumor masses in the small intestine. Grossly, the intestinal wall was thickened, and the lumen of the affected intestine was usually narrowed. Microscopically, we observed transmural diffuse invasion of round to pleomorphic tumor cells. Tumor cells showed varying morphology, from scanty to abundant cytoplasm, and round to ovoid nuclei with scattered to dense chromatin. In seven of the dogs, tumor cells had infiltrated into the epithelium. All showed infiltration of eosinophils and all 11 tumors had a T-cell phenotype (CD3+, CD79-). Only one tumor stained positive for the mast cell marker c-kit and none was positive for mast cell tryptase. We did not observe ultrastructurally apparent granules in any of the tumor cells. These results suggest that, in dogs, T-cell lymphomas of intestinal origin resemble mast cell tumors of intestinal origin with respect to cell structure and eosinophil infiltration. Therefore, in the absence of epitheliotropism, it is difficult to confirm the differential diagnosis without immunostaining for mast cell and lymphocyte markers, including mast cell tryptase, c-kit, CD3, and CD79.

Animals↗

Inhaled salmeterol and albuterol in asthmatic patients receiving high-dose inhaled corticosteroids.

Salmeterol may be useful in the treatment of asthmatic patients requiring high-dose inhaled steroids, and there have been debates about its anti-inflammatory action. We have compared the efficacy and effects on serum inflammatory markers, including soluble interleukin 2R (sIL-2R), eosinophil cationic protein (ECP), and tryptase of salmeterol and albuterol in 20 patients with moderate to severe asthma who were all receiving high-dose inhaled corticosteroids and inhaled beta 2-agonist on demand. After a 2-week run-in period, they received, in a randomized, crossover, double-blind and placebo-controlled manner, either salmeterol, 50 micrograms twice a day, or albuterol 400 micrograms, four times a day, from a powder inhaler during two 2-week treatment periods, separated by a 2-week washout. Compared with albuterol, salmeterol treatment was associated with better morning and mean peak expiratory flow (p = 0.013 and 0.016, respectively), less daytime and nocturnal symptoms (p = 0.008 and 0.01, respectively), reduced requirement of rescue albuterol (p = 0.04), and better efficacy rating by patients (p = 0.04). However, serum concentration of sIL-2R was significantly higher during regular albuterol treatment (p = 0.014) but no differences were seen in the concentrations of ECP and tryptase between the two treatment periods. We conclude that inhaled salmeterol, 50 micrograms twice daily, confers a better control of asthma than albuterol, 400 micrograms four times daily, in patients with moderate to severe disease, and the latter treatment may be associated with increased T-lymphocyte activation.

Administration, Inhalation↗

Formoterol added to low-dose budesonide has no additional antiinflammatory effect in asthmatic patients.

STUDY OBJECTIVE: Adding inhaled long-acting beta2-agonists to a low dose of inhaled corticosteroids (ICSs) results in better asthma control than increasing the dose of ICSs. An important, but as yet unresolved, question is whether this is due to an additional reduction of airway inflammation. DESIGN: Double-blind, parallel-group trial. PATIENTS: Forty asthma patients (FEV1, 50 to 90% predicted; provocative concentration of a substance [methacholine] causing a 20% fall in FEV1 of < 8 mg/mL; no ICSs in the last 4 weeks). INTERVENTIONS: Randomization to 8 weeks of treatment with 100 microg of budesonide bid plus placebo (BUD200) or 100 microg of budesonide bid plus 12 microg of formoterol (BUD200 + F). Then the dose of budesonide (BUD) was increased to 400 microg bid in both groups for another 8 weeks. Bronchial biopsy specimens were collected before, and after 8 and 16 weeks of treatment. Eosinophils (major basic protein [MBP]) and mast cells (tryptase) were analyzed by immunohistochemistry. RESULTS: BUD200 reduced the MBP staining (p = 0.008) and tryptase staining (p = 0.048) in the epithelium compared to baseline levels. There were no significant differences between the BUD200 and BUD200 + F groups. In both groups, increasing the dosage of BUD to 800 microg had no significant additional antiinflammatory effect. CONCLUSIONS: Our results demonstrate that BUD administered at a low dose has significant antiinflammatory effects in patients with mild asthma. No significant additional antiinflammatory effects could be demonstrated either by adding formoterol or by increasing the dose of BUD.

Administration, Inhalation↗

Accumulation of mini-plasmin in the cerebral capillaries causes vascular invasion of the murine brain by a pneumotropic influenza A virus: implications for influenza-associated encephalopathy.

The infectivity and pathogenicity of influenza virus are primarily determined by host cellular trypsin-type processing proteases which cleave the viral membrane fusion glycoprotein hemagglutinin (HA). Therefore the distribution of the processing protease is a major determinant of the infectious organ tropism. The common epidemic human influenza A virus is pneumotropic and the HA processing proteases tryptase Clara, mini-plasmin, tryptase TC30 and ectopic anionic trypsin have all been isolated from mammalian airways. However, the pneumotropic influenza virus occasionally causes severe brain edema, particularly in children presenting with Reye's syndrome treated with aspirin, or in children with influenza-associated encephalopathy without antipyretic treatment. We have observed that, after influenza virus infection, the accumulation of mini-plasmin in the cerebral capillaries in mice with a congenital or acquired abnormality of mitochondrial beta-oxidation mimicking the pathological findings of Reye's syndrome, causes an invasion and multiplication of the pneumotropic influenza virus at these same locations. From these findings, we hypothesize that the accumulated mini-plasmin modifies the brain capillaries from a non-permissive to a permissive state, thereby allowing multiplication of pneumotropic influenza virus. In addition, mini-plasmin proteolytically destroys the blood-brain barrier. These pathologic findings, consistent with encephalopathy in mice with a systemic impairment of beta-oxidation, may have implications for human influenza encephalopathy.

Animals↗

Role of calcium in histamine release from rat mast cells activated by various secretagogues; intracellular calcium mobilization correlates with histamine release.

Anti-IgE, con A or antigen caused an increase in the intracellular calcium concentration, [Ca2+]i, of mast cells. The increase occurred in two stages: a rapid initial rise caused by Ca-mobilization from intracellular Ca-stores and a second sustained rise caused by an influx of extracellular calcium (White, J.R., Pluznik, D.V., Ishizaka, K. & Ishizaka, T. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 8193-8197). The rapid initial rise was followed by a release of histamine, which seemed to coincide with the second rise. A23187 and compound 48/80 induced a rapid initial rise in [Ca2+]i, followed by a gradual decrease in [Ca2+]i, GMCHA-OPhBut, a specific pH 7 tryptase inhibitor (Muramatu, M., Ito, T., Takei, M. & Endo, K. (1988) Biol. Chem. Hoppe-Seyler 369, 617-625), strongly inhibited both the initial and second rises of [Ca2+]i, as well as histamine release by these secretagogues, and its effects on the initial rise were closely correlated with those on histamine release. Addition of GMCHA-OPhBut immediately after the initial rise strongly inhibited the second rise, thereby decreasing the final [Ca2+]i. These results strongly suggested a possible involvement of pH 7 tryptase, not only in Ca-mobilization leading to the initial rise in [Ca2+]i, but also in the second rise. Trapping of extracellular calcium by 3mM EGTA decreased both the initial rise in [Ca2+]i and histamine secretion induced by anti-IgE or con A; the magnitude of this effect depended on the time between induction and EGTA addition. Histamine release was closely correlated with the initial rise in [Ca2+]i. Similar results were obtained with A23187, but even 5 min after the addition of EGTA an initial rise of [Ca2+]i could still be induced, and histamine (30% of total histamine) was still released. However, A23187 did not induce a rise in [Ca2+]i in mast cells which had been exhaustively washed with Tyrode/Hepes solution containing 3mM EGTA, followed by suspension in the same solution. Even at 20 min after depletion of the extracellular calcium, compound 48/80 still caused an initial rise in [Ca2+]i to above half the maximal value, and histamine secretion was even less affected. The above results indicated that the initial rise in [Ca2+]i, due to Ca-mobilization, correlates with the histamine release promoted by the secretagogues described. On the other hand, isoproterenol strongly induced histamine secretion with no change of [Ca2+]i, while EGTA treatment prior to isoproterenol stimulation had no effect on histamine release, indicating a different secretion mechanism.

Aminoquinolines↗

Targeting serine proteases in asthma.

Leukocytes and lung structural cells contribute to the pathophysiology of asthma through the production of numerous mediators including serine proteases. Such proteases include mast cell tryptase and chymase; neutrophil elastase, cathepsin G and myeloblastin (proteinase 3); bronchial epithelial cell-derived transmembrane protease, serine 11D (human airway trypsin-like protease); cytotoxic T lymphocyte- and natural killer cell-derived granzyme B; and, eosinophil serine protease 1 (testisin). Considerable effort to develop potent and selective inhibitors, mostly non-peptidic, especially targeting tryptase and chymase have been made in the last few years. This review presents promising inhibitors, currently in the research and development pipeline. Some endogenous inhibitors and other compounds purified from non-human species are also discussed.

Animals↗