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PubMed1997

Intranasal capsaicin is efficacious in non-allergic, non-infectious perennial rhinitis. A placebo-controlled study.

BACKGROUND: Several authors described capsaicin, the pungent substance in red pepper, as an efficacious therapy for non-allergic non-infectious perennial rhinitis (NANIPER). Repeated capsaicin application induces peptide depletion and specific degeneration of the unmyelinated sensory C-fibres in the nasal mucosa. METHODS: We performed a placebo-controlled (NaCl 0.9%) study with 25 NANIPER patients. Daily record charts and visual analogue scales (VAS) were used for clinical evaluation. Nasal lavages were obtained before, during, and after treatment. RESULTS: There was a significant and long-term reduction in the VAS scores in the capsaicin group. No significant difference was found between the placebo and capsaicin treated groups for the mean group concentrations of leukotriene (LT) C4/D4/E4, prostaglandin D2 (PGD2), and tryptase. The levels of mast cell mediators, tryptase and PGD2, and leukotrienes, mediators derived from a variety of inflammatory cells, were low at baseline and comparable with levels observed in nasal lavages obtained from normals. CONCLUSION: As involvement of inflammation could not be demonstrated, it is not surprising that capsaicin has no effect on inflammatory mediators. This suggests that inflammatory cells do not play a major part in the pathogenesis of NANIPER.

Adolescent↗
PubMed1999

Airway endothelin levels in asthma: influence of endobronchial hypertonic saline challenge.

BACKGROUND: The pathophysiology of exercise-induced asthma is not well understood. Hypertonicity of the airway lining fluid resulting from loss of water due to hyperventilation is considered to play a role, but the precise mechanism by which hypertonicity can induce bronchoconstriction is unknown. Peptides of the endothelin (ET) family have potent smooth muscle contractile properties, and have been linked to airway narrowing in stable asthma. We postulated that ET release may contribute to the acute bronchoconstrictor response induced by a hypertonic stimulus. METHODS: Seven male asthmatic subjects underwent local endobronchial challenge with hypertonic (3.6%) saline and, as a control, isotonic (0.9%) saline aerosols in separate bronchopulmonary segments. Bronchoalveolar lavage (BAL) was performed at both sites during the phase of immediate bronchoconstriction. Concentrations of immunoreactive ET and of the mast cell products, histamine, tryptase and prostaglandin D2, in BAL fluid were measured. RESULTS: Concentrations of ET in BAL fluid from the hypertonic saline-challenged sites were significantly lower than those in BAL fluid from sites exposed to isotonic saline (0.19 [0.11-1.24] fmol/mL vs. 0.40 [0.20-2.36] fmol/mL, P<0.05). Concentrations of histamine, tryptase, and prostaglandin D2 did not differ significantly between the two sites. CONCLUSIONS: These findings do not support the hypothesis that ET release within the airway lumen is involved in the bronchoconstrictor response induced by hypertonic saline.

Adult↗
PubMed1999

Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma.

BACKGROUND: We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods. METHODS: A nonbronchoscopic bronchoalveolar lavage (BAL) procedure was performed on children presenting for an elective surgical procedure. Eosinophil-derived (eosinophil cationic protein, ECP) and mast cell-derived (histamine/tryptase) mediator concentrations were measured in the BAL fluid. A detailed history and serum immunoglobulin E were used to classify the children into four groups: atopic with and without asthma, viral-associated wheeze and normal controls. RESULTS: The ECP concentrations in BAL from atopic asthmatic subjects were significantly higher than those measured in BAL from normal controls (P < 0.01), no other groups differed significantly. Histamine concentrations were elevated in both the atopic asthmatic and viral-associated wheeze groups compared with controls (P < 0.02) and additionally higher concentrations were obtained in atopics with asthma compared with atopics without asthma (P < 0.03). Tryptase concentrations did not differ between groups, although the tryptase and histamine concentrations correlated significantly (r = 0.78, P < 0.0001). CONCLUSIONS: Elevated histamine concentrations were found in children with wheeze regardless of the aetiology, whereas ECP was only elevated in those asthmatics with atopy. This suggests that even in relatively quiescent periods, there is some on going activation of airway eosinophils in children with atopic asthma.

Adolescent↗
PubMed2000

Nasal lavage mediator profile and cellular composition of nasal brushing material during latex challenge tests.

BACKGROUND: Recent studies have shown that airborne latex allergens cause allergic rhinitis and bronchial asthma. OBJECTIVE: The aim of this study was to investigate the association between the development of rhinitis reactions during workplace-related inhalative challenge tests and nasal allergic inflammation. METHODS: Thirty-two health care workers (HCWs) with suspected respiratory hypersensitivity to latex allergens underwent an inhalative workplace-related challenge test with powdered latex gloves. Nasal lavage fluid (NALF) and nasal brushing (NAB) material were collected before and after exposure (30 min, 2, 6 and 24 h) to determine mediator and cellular composition. In addition, lung function parameters and nasal flow were recorded. Furthermore, six healthy controls underwent nasal brushing and nasal lavage without latex allergen challenge at the same time intervals. RESULTS: Twenty-six HCWs showed acute rhinitis by contact to airborne latex allergen exposure and 10 of them had an additional asthma response. Only in responders, significantly increased eosinophil levels were found 6 h (P < 0.00001) and 24 h (P < 0.0005) post-challenge when compared with the prechallenge values. The ECP levels measured 2, 6 and 24 h post-challenge in the responder group were significantly elevated when compared with the prechallenge values as well as with the non-responders (6 h: P < 0.05, 24 h: P < 0.00001 afterwards). Only in some concentrated NALF samples of responders collected 30 min post-challenge (seven out of 15) tryptase concentration above the detection limit were found. The NO derivative concentrations in NALF were significantly increased 6 h post-challenge compared with the prechallenge values (P < 0.05) and were significantly higher in responders than in non-responders and in controls (P < 0.002). IL-5 levels increased post-challenge in the responder group with a pronounced effect 6 h after challenge (P < 0.001). Overall, a variety of parameters was significantly correlated (e.g. ECP with NO derivatives, r = 0.792 P < 0.002). CONCLUSIONS: Our data demonstrate for the first time that nasal and bronchial hyperreactivity to airborne latex allergens are associated with an increase of eosinophils and mediators (e.g. ECP, NO derivatives, IL-5, tryptase) in nasal mucosa. The combined use of NAB (for cells) and NALF (for mediators) appears to be a useful model to monitor nasal inflammation during workplace-related challenge tests.

Administration, Inhalation↗
PubMed2000

Nasal hyperosmolar challenge with a dry powder of mannitol in patients with allergic rhinitis. Evidence for epithelial cell involvement.

BACKGROUND: The responses to airway hyperosmolar challenges probably involve various inflammatory mediators. However, it is not fully understood which cell type/types are the source of these mediators. Potential cell types include mast cell, epithelial cell and the sensory c-fibre nerve cell. OBJECTIVE: To clarify which cell types are involved with the mediator response to hyperosmolarity in the human airway. METHODS: Ten healthy subjects, 11 patients with nonactive allergic rhinitis, and nine with active allergic rhinitis were challenged intranasally with mannitol powder, and with sham provocation, on separate days. Symptoms were assessed by visual analogue scales and nasal patency by measuring the nasal peak inspiratory flow (nPIF). Nasal lavage fluid levels of alpha(2)-macroglobulin (an index of plasma extravasation), substance P (an index of sensory nerve cell activation), tryptase (an index of mast cell activation) and 15-hydroxyeicosatetraenoic acid (15-HETE, an index of epithelial cell activation) were analysed. RESULTS: Immediate, although transient burning was the most prominent symptom in all groups whereas only the patients with active rhinitis experienced a fall in nPIF. Mannitol significantly increased the nasal lavage fluid 15-HETE levels in the allergic patients (P < 0.01 vs the sham challenge), but not in the healthy subjects. The increase in 15-HETE correlated with nasal symptoms for itching (r(s) = 0.65, P = 0.019) and burning (r(s) = 0.72, P = 0.009). Detectable levels of tryptase was found only in five allergic subjects. Lavage levels of substance P and alpha(2)-macroglobulin did not not change. CONCLUSION: Epithelial cell seems to be involved with the mediator response to airway hyperosmolar challenge. The roles of sensory c-fibre nerve cell and mast cell remained less clear.

Adult↗
PubMed2002

Nasal challenges with recombinant derivatives of the major birch pollen allergen Bet v 1 induce fewer symptoms and lower mediator release than rBet v 1 wild-type in patients with allergic rhinitis.

BACKGROUND: Genetic engineering of the major birch pollen allergen (Bet v 1) has led to the generation of recombinant Bet v 1 derivatives with markedly reduced IgE-binding capacity, but with retained T cell activating ability. OBJECTIVE: To compare the mucosal reactivity to rBet v 1 derivatives with rBet v 1 wild-type as basis for new therapeutic strategies for birch pollen allergy based on mucosal tolerance induction. METHODS: Outside the pollen season, 10 patients with birch pollen allergic rhinitis and mild asthma underwent four nasal challenge-sessions in a randomized, double-blind, and cross-over design, employing increasing doses of rBet v 1 fragment mix, rBet v 1 trimer, rBet v 1 wild-type and diluent (albumin). Nasal lavage fluids (NAL) were collected before the challenge-series as well as 10 min, 4 and 24 h thereafter. Nasal lavage fluid levels of tryptase as well as EPO and ECP were measured as indices of mast cell and eosinophil activity, respectively. RESULTS: All 10 patients tolerated the highest accumulated dose, 8.124 microg, when challenged with rBet v 1 trimer, eight with rBet v 1 fragments compared to one when challenged with rBet v 1 wild-type. No late phase reactions were observed. The change in tryptase levels (pre-challenge vs. 10 min) was significantly lower after challenges with rBet v 1 trimer and rBet v 1 fragments than with rBet v 1 wild-type. The change in EPO/ECP concentration pre-challenge versus 4 h post-challenge was lower for rBet v 1 trimer and the change was significantly lower when pre-challenge versus 24 h post-challenge to rBet v 1 fragments and rBet v 1 wild-type was examined. CONCLUSION: The derivatives induced significantly fewer symptoms and lower mast cell and eosinophil activation than rBet v 1 wild-type upon application to the nasal mucosa. They could in the future be candidates for immunotherapy based on mucosal tolerance induction.

Adult↗
PubMed2002

Temporal distribution of distinct mast cell phenotypes during intestinal schistosomiasis in mice.

Mastocytosis is a common feature of helminth infection in most host species. We examined the temporal distribution and phenotype of mast cells during intestinal schistosomiasis in mice, using antibodies directed against histamine, a general mast cell marker, against mouse mast cell protease-1 (MMCP-1), a mucosal mast cell (MMC) marker, and against tryptase, a predominantly connective tissue mast cell (CTMC) marker. Ileal paraffin and/or cryosections of control, 8- and 15-week-infected mice were quantitatively analysed. In the intestinal wall of non- and unisexual infected mice, a few dispersed mast cells were detected. In infected mice, a transient increase of mast cells in the mucosa and a gradual increase in the outer muscle layer were observed. MMCP-1 expressing MMCs were predominantly present in the mucosa during the acute phase [8 weeks postinfection (p.i.)], while tryptase and histamine immunoreactivity demonstrated that two subsets of CTMCs were predominantly present in the outer muscle layer at 15 weeks p.i. (chronic phase). In conclusion, these results reveal that, in mice, both MMCs and CTMCs are involved in the inflammatory response during schistosomiasis. The recruitment of each mast cell population is time-dependent and occurs at different locations. These data suggest that mastocytosis is associated with motility-related gastrointestinal symptoms and egg excretion.

Animals↗
PubMed2002

Influence of vitamin E on mast cell mediator release.

We investigated the influence of vitamin E on mediator activity and release in a canine mastocytoma cell line (C2) as a model for canine atopic dermatitis. Cells were incubated without and with vitamin E (100 microm) for 24 h. The histamine and prostaglandin D2 (PGD2) release as well as the chymase and tryptase activity were measured. To stimulate the PGD2 and histamine release, cells were incubated with the wasp venom peptide mastoparan (50 microm) for 30 or 45 min. Nonstimulated as well as mastoparan-stimulated histamine and PGD2 release was reduced significantly in vitamin E-treated cells. The activity of chymase tended to decrease, but the tryptase activity of C2 cells was not influenced by vitamin E. These results indicate that vitamin E decreased the production and release of inflammatory mediators in C2 cells, suggesting that vitamin E might have a possible beneficial effect in inflammatory diseases.

Animals↗
PubMed2000

Subtypes of bladder mast cells in interstitial cystitis.

BACKGROUND: Because the types of mast cells present in the bladder of patients with interstitial cystitis (IC) have not been elucidated, we have used immunohistochemical techniques to determine which of the mast cell types is present in biopsy specimens. METHODS: For all patients diagnosed with IC (n = 10; female) their symptoms satisfied the criteria proposed by the National Institutes of Health criteria of IC and six patients suffering from bladder tumors were selected as control patients. Adjacent sections of paraffin-embedded tissues that had been fixed in Carnoy's solution were reacted with either antitryptase or antichymase antibodies. RESULTS: In detrusor and in mucosa, the number of tryptase-positive and chymase-negative mast cells (MC(T)) was 146+/-25 and 81+/-31 cells/mm2, respectively, and the number of tryptase-positive and chymase-positive mast cells (MC(TC)) was 124+/-50 and 54+/-20 cells/mm2, respectively. These numbers were significantly greater than those of the control group. A significant negative correlation (P<0.005; R = 0.943) was observed between the number of MC(TC) and the bladder capacity. The number of mast cells obtained by toluidine blue staining in detrusor and in mucosa was 95+/-68 and 71+/-39 cells/mm2, respectively, suggesting that staining with toluidine blue underestimated the number of mast cells. CONCLUSIONS: Mast cells were significantly increased in number in both the mucosa and detrusor of bladder specimens from IC patients compared with those from control. The MC(TC) may be the type of mast cell dominantly present in the bladder of IC patients. The MC(TC) in detrusor increased with the progression of contracted bladder.

Adult↗
PubMed2003

Sodium ferric gluconate complex in hemodialysis patients. II. Adverse reactions in iron dextran-sensitive and dextran-tolerant patients.

BACKGROUND: Iron dextran administration is associated with a high incidence of adverse reactions including anaphylaxis and death. Although dextran, rather than iron, is believed to be the cause of these reactions, it is not known whether iron dextran-sensitive patients can be safely administered another form of parenteral iron, sodium ferric gluconate in sucrose (SFGC). METHODS: In a 69 center, prospective, double-blind, controlled trial of safety and tolerability of SFGC, the rate of reactions to SFGC and placebo in 144 iron dextran-sensitive patients was compared with 2194 patients who were previously tolerant to iron dextran preparations. Serum tryptase levels, a marker of mast cell degranulation, also were measured. RESULTS: Among 143 iron dextran-sensitive patients exposed to SFGC, three (2.1%) were intolerant. All three had suspected allergic events to SFGC, including one patient with a serious reaction (0.7%). One dextran-sensitive patient (0.7%) had a suspected allergic reaction after placebo. In contrast, among 2194 iron dextran-tolerant patients, reactions to SFGC were significantly less common, with SFGC intolerance seen in seven patients (0.3%; P = 0.020), including five (0.2%) who had suspected allergic events (P = 0.010), but none who had serious events (0.0%; P = 0.061). Two iron dextran-tolerant patients (0.09%) had allergic-like reactions following placebo injections. Two of the three suspected allergic events in the iron dextran-sensitive group were confirmed as mast cell dependent by a 100% increase in serum tryptase, while there were no confirmed allergic events in the iron dextran-tolerant group. Long-term exposure to SFGC in iron dextran-sensitive patients resulted in intolerance in only one additional patient and no serious adverse events. CONCLUSIONS: Patients with a history of iron dextran sensitivity had approximately sevenfold higher rates of reaction to both placebo and SFGC compared to iron dextran tolerant patients. However, logistic regression analysis, performed to account for the higher reaction rate to placebo, suggests that this increased reactivity was not drug-specific nor immunologically mediated, but represented host idiosyncrasy. These results support the conclusions that reactions to SFGC can be attributed to pseudoallergy, and that SFGC is not a true allergen.

Drug Hypersensitivity↗
PubMed1999

Mast cell activation in children with migraine before and after training in self-regulation.

Migraine may affect as many as 9% of all schoolchildren and often presents with abdominal symptoms of pain, nausea, and vomiting. Even though the pathophysiology of migraine remains unknown, self-regulation techniques appear to be more effective in prevention of childhood migraine than conventional pharmacotherapy which is often associated with adverse effects. Mast cells have been implicated in the pathogenesis of migraine in adults, but have not been previously studied in children with migraine. Mast cells are found close to the vessels and nerves in the meninges where they can release multiple vasoactive, neurosensitizing, and pro-inflammatory mediators. Therefore, we investigated whether children with migraine may have increased urinary levels of mast cell mediators and whether practicing relaxation imagery exercises has an effect on the frequency of headache, as well as on mast cell activation. Urine was collected for 24 hours from children with and without migraine after a 5-day amine-restricted diet. Children with migraine also collected urine during migraine episodes. The mean levels of urinary histamine, its main metabolite, methylhistamine, and the mast cell enzyme, tryptase, were higher in children than generally found in adults, but they did not differ statistically in any of the categories studied. However, in 8 of 10 children who practiced relaxation imagery techniques and successfully reduced the number of migraines, the urine tryptase levels were also significantly lower. There was no relationship between successful practice and sex or age of the child. These results suggest that stress may activate mast cells which could be involved in the pathophysiology of migraine.

Child↗
PubMed1995

Effect of colonoscopy premedication containing diazepam and pethidine on the release of mast cell mediators in gut mucosal samples.

BACKGROUND AND STUDY AIMS: To date there is no information available on whether drugs that are commonly used in premedication for colonoscopy procedures, such as diazepam and pethidine, may activate intestinal mast cells and thereby give rise to adverse effects. Since opioids such as pethidine are well-known for their ability to induce histamine release from several mast cell subtypes, the present study investigated the effect of diazepam and pethidine, intravenously administered as premedication for colonoscopy, on mast cell mediator secretion from colonic and rectal mucosa. PATIENTS AND METHODS: The secretion of the mast cell mediators histamine and tryptase was followed from biopsies of patients with and without premedication for 30 minutes in an air-bubbled incubation medium (mucosa oxygenation). The mediator release and tissue histamine content were studied prospectively in 17 control persons (histologically normal mucosa) as well as in 71 patients with inflammatory bowel disease (IBD) (histologically uninvolved and involved tissue). RESULTS: Although a significant accumulation of histamine was found in inflamed IBD-tissue, the results indicate, however, that this premedication does not enhance the release of histamine or tryptase from gut mucosal samples, neither in the histologically normal mucosa of control persons nor in tissue unaffected or affected by inflammatory bowel disease. CONCLUSION: This study demonstrates that colonoscopy premedication with diazepam and pethidine is safe in terms of gut mucosal mast cell activation.

Adult↗
PubMed2001

A randomized study to evaluate the effect of a perioperative infusion of dopexamine on colonic mucosal ischemia after aortic surgery.

PURPOSE: Colonic ischemia after aortic surgery is associated with increased mortality and morbidity rates. This study was conducted as a single-center side arm to a multicenter, randomized, placebo-controlled study to evaluate the effect of dopexamine hydrochloride on its incidence. METHODS: Thirty patients, mean age 65.1 years (range, 46-84), undergoing elective infrarenal aortic surgery were entered. Preoperative hemodynamic and respiratory parameters were optimized. Patients were then randomly assigned to receive a perioperative infusion of dopexamine at 2 microg/kg per minute (n = 12) or 0.9% saline placebo (n = 18). All patients underwent colonoscopy and biopsy preoperatively and 1 week postoperatively. Specimens were assessed for evidence of mucosal ischemia, presence of mast cell tryptase, myeloperoxidase activity, and both the inducible and endothelial isoforms of nitric oxide synthase. RESULTS: There was no significant difference in perioperative fluid and blood requirements or hemodynamic and respiratory parameters between the two groups. However, there was significantly less evidence of mucosal ischemic changes in dopexamine-treated patients (n = 1) compared with placebo (n = 8) (P =.049). Furthermore, when preoperative biopsies were compared with those performed 1 week postoperatively, nine (50%) patients in the placebo group and two (16.7%) in the dopexamine group scored worse. Although there was no significant difference in inflammatory markers between the two groups, both mast cell tryptase and myeloperoxidase expression were increased in patients with histologic evidence of ischemia (P <.05). Furthermore, inducible nitric oxide synthase staining within the vascular (P =.001) and lamina propria (P <.05) components of the mucosa was also significantly greater. CONCLUSION: A perioperative dopexamine infusion affords significant histologic protection to colonic mucosa after aortic surgery.

Adult↗
PubMed2005

Human airway epithelial cell determinants of survival and functional phenotype for primary human mast cells.

Mast cells (MCs) are found in increased numbers at airway mucosal surfaces in asthmatic patients. Because human airway epithelial cells (HAECs) actively participate in airway inflammatory responses and are in direct contact with MCs in the mucosa, we hypothesized that HAEC-MC interactions may contribute to the differentiation and survival of MCs in the airway mucosa. Here, we show that HAECs express mRNA and protein for soluble and membrane-bound stem cell factor, releasing soluble stem cell factor into the cell culture supernatant at a concentration of 5.9 +/- 0.1 ng per 10(6) HAEC. HAECs were able to support MC survival in coculture in the absence of any exogenous cytokines for at least 4 d. Before the initiation of coculture, MCs were uniformly tryptase and chymase (MC(TC)) double positive, but by 2 d of coculture the majority of MCs expressed tryptase (MC(T)) alone. MCs supported in coculture generated low amounts of cysteinyl-leukotrienes (cys-LT) after FcepsilonRI-dependent activation (0.2 +/- 0.1 ng of cys-LT per 10(6) cells) and required priming with IL-4 and IL-3 during coculture to achieve a quantity of cys-LT generation within the range expected for human lung mucosal MC (26.5 +/- 16 ng of cys-LT per 10(6) cells). In these culture conditions, HAECs were able to direct mucosal MC protease phenotype, but T cell-derived Th2 cytokines were required for the expression of a functional airway MC eicosanoid phenotype. Thus, distinct cell types may direct unique aspects of reactive mucosal MC phenotype in the airways.

Analysis of Variance↗
PubMed1995

Packaging of proteases and proteoglycans in the granules of mast cells and other hematopoietic cells. A cluster of histidines on mouse mast cell protease 7 regulates its binding to heparin serglycin proteoglycans.

Mouse mast cell protease 7 (mMCP-7) is a tryptase stored in the secretory granules of mast cells. At the granule pH of 5.5, mMCP-7 is fully active and is bound to heparin-containing serglycin proteoglycans. to understand the interaction of mMCP-7 with heparin inside and outside the mast cell, this trytase was first studied by comparative protein modeling. The "pro" form of mMCP-7 was then expressed in insect cells and studied by site-directed mutagenesis. Although mMCP-7 lacks known linear sequences of amino acis that interact with heparin, the three-dimensional model of mMCP-7 revealed an area on the surface of the folded protein away from the substrate-binding site that exhibits a strong positive electrostatic potential at the acidic pH of the granule. In agreement with this calculation, recombinant pro-mMCP-7 bound to a heparin-affinity column at pH 5.5 and readily dissociated from the column at pH > 6.5. Site-directed mutagenesis confirmed the prediction that the conversion of His residues 8,68, and 70 in the positively charged region into Glu prevents the binding of pro-mMCP-7 to heparin. Because the binding requires positively charged His residues, native mMCP-7 is able to dissociate from the protease/proteoglycan macromolecular complex when the complex is exocytosed from bone marrow-derived mast cells into a neutral pH environment. Many hematopoietic effector cells store positively charged proteins in granules that contain serglycin proteoglycans. The heparin/mMCP-7 interaction, which depends on the tertiary structure of the tryptase, may be representative of a general control mechanism by which hematopoietic cells maximize storage of properly folded, enzymatically active proteins in their granules.

Amino Acid Sequence↗
PubMed2003

Suppressor of cytokine signaling 1 regulates an endogenous inhibitor of a mast cell protease.

Suppressor of cytokine signaling 1 (SOCS1) is a negative regulator of c-Kit and interleukin-3 (IL-3) receptor signaling. We examined the role of SOCS1 in regulating IL-3-induced cell growth of primary bone marrow-derived mast cells (BMMCs) from SOCS1-/- mice. Instead of showing increased proliferation, SOCS1-deficient BMMCs responded poorly to IL-3 and stem cell factor. SOCS1-/- BMMCs showed increased apoptosis and defective cell cycle entry. We show that the growth retardation of SOCS1-/- BMMCs was due to a cell intrinsic defect. Protein tyrosine phosphorylation following IL-3 stimulation was markedly diminished in SOCS1-/- BMMCs. Intriguingly, JAK2 and STAT5 proteins were selectively diminished in SOCS1-/- BMMCs, which also showed lower molecular mass products of p85 and Vav suggesting proteolytic degradation. Incubation of the SOCS1-/- BMMC lysate with STAT5, p85, and Vav immunoprecipitated from SOCS1+/+ cells directly demonstrated the dysregulated proteolytic activity in SOCS1-/- BMMCs. The proteolytic activity in SOCS1-/- BMMCs was selectively inhibited by phenylmethylsulfonyl fluoride and soybean trypsin inhibitor, suggesting that the protease regulated by SOCS1 is a tryptase. The dysregulated tryptase in SOCS1-/- BMMCs is unlikely to be mMCP6 or mMCP7, because the enzyme activity was not inhibited by Polybrene but was inhibited by normal mouse plasma. SOCS1+/+ BMMC lysate inhibited the proteolytic activity present in SOCS1-/- BMMC lysate, indicating that SOCS1-/- BMMCs lack an endogenous protease inhibitor. These results show that SOCS1 is required for the expression and/or stability of an endogenous protease inhibitor, which protects mast cells from their own proteolytic enzymes.

Animals↗
PubMed2003

The effect of topically applied secretory leukocyte protease inhibitor on the eosinophil response in the late phase of allergic conjunctivitis.

PURPOSE: This study examined the effects of secretory leukocyte protease inhibitor (SLPI), a protease inhibitor in tears, in allergic conjunctivitis. METHODS: Conjunctiva of male Hartley guinea pigs sensitized with ovalbumin were treated with SLPI or the vehicle 10 min before antigen challenge or simultaneously. The animals were sacrificed after antigen challenges of 0-24 h duration, and the inhibition of eosinophil conjunctival migration and degranulation by SLPI was analyzed histochemically. The effects of SLPI on mast cell chymase and tryptase were also examined. RESULTS: Treatment of sensitized guinea pigs with SLPI suppressed the conjunctival recruitment and degranulation of eosinophils after antigen challenge for 6 h, inhibiting the development of allergic conjunctivitis. The effects of SLPI were observed at concentrations > or =0.1 microM, with a peak at 5 microM. SLPI inhibited chymase in a dose-dependent manner, but had no effect on tryptase. CONCLUSION: The topical SLPI application may be therapeutic in allergic conjunctivitis.

Administration, Topical↗
PubMed2003

Human mast cell subtypes in conjunctiva of patients with atopic keratoconjunctivitis, ocular cicatricial pemphigoid and Stevens-Johnson syndrome.

PURPOSE: Investigate mast cell (MC(S)) subtypes in atopic keratoconjunctivitis (AKC), ocular cicatrical pemphigoid (OCP), and Stevens-Johnson Syndrome (SJS). METHODS: MC(S) subtypes were determined by immunohistochemistry of conjunctiva (obtained from 34 patients--9 AKC, 9 OCP, 9 SJS and 7 normal) using monoclonal antibodies directed against chymase (MC(C)) and tryptase (MC(T)). Double staining was used to distinguish MC(S) as positive for both chymase and tryptase (MC(TC)). RESULTS: The number of MC(S) was significantly increased in AKC, OCP and SJS patients, compared to normal subjects. MC( C) were especially high in AKC, and moderately high in OCP. MC(T ) and MC(TC) were similar in each disease group. CONCLUSIONS: While the AKC findings were not surprising, the result in OCP and SJS suggests that MC(S) play an underappreciated role in the inflammatory process of these disorders. Disparate proportions of MC(S) subtypes in these diseases may imply differential functions of MC(S) in these disorders.

Adult↗