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PubMed2006

Analysis of MC(T) and MC(TC) mast cells in tissue.

The MC(TC) and MCT types of human mast cells initially were recognized on the basis of the protease compositions of their secretory granules, with tryptase, chymase, carboxypeptidase A3, and cathepsin G in the former and only tryptase in the latter. Antibodies against chymase and tryptase traditionally have been used to distinguish these mast cell types from one another. Antitryptase antibodies label all mast cells; antichymase labels only the MC(TC) type. To identify both types in a tissue section, a sequential double-labeling scheme was developed to first stain chymase-positive cells, thereby blocking their recognition by the antitryptase antibody, which will label only the chymase-negative mast cells. In general, these immunocytochemical techniques are more sensitive and specific than classical histochemical techniques for detecting mast cells.

Biomarkers↗
PubMed2006

Hymenoptera venom immunotherapy and field stings.

BACKGROUND: Anaphylactic sting reactions in patients with Hymenoptera venom allergy are prevented by venom immunotherapy (VIT) in most patients. OBJECTIVE: The aim of this study was to investigate re-sting reactions in the field during VIT or during an observation period of up to 13 years after cessation of treatment. Furthermore we sought to identify patients at higher risk of developing a systemic allergic reaction (SAR) and to assess possible correlations with basal serum tryptase concentration. METHODS: The clinical data of 192 patients with a recorded field sting during VIT were evaluated and the patients were questioned regarding possible re-stings after cessation of VIT. Baseline mast-cell tryptase concentrations and specific IgE were analyzed in patients with a reported SAR. RESULTS: Of 192 patients with reported re-stings in the field, 27 developed SARs (14.1%). A SAR occurred in 11.9% of the stings delivered during VIT, whereas 9.7% of the stings resulted in a SAR after VIT. The majority of SARs in response to a field sting during VIT were mild, whereas severe SARs occurred more often after VIT and repeated reexposure. Out of 23 patients with reported SARs, 2 (8.7%) had elevated basal serum tryptase. CONCLUSIONS: VIT lasting for at least 3 years is effective in protecting the vast majority of patients. The individual predictability of the response of patients to a field sting is low. SARs of increased severity mainly occur after therapy and after tolerating consecutive stings.

Adolescent↗
PubMed1994

Kit ligand/mast cell growth factor-independent differentiation of mast cells in myelodysplasia and chronic myeloid leukemic blast crisis.

Autonomous, factor-independent growth and differentiation of malignant cells in preleukemic and leukemic disease states is a well-recognized phenomenon and is often associated with a poor prognosis. Mast cells are distinct hematopoietic cells and express a unique profile of antigens. Growth and differentiation of normal mast cells is dependent on mast cell growth factor (MGF), the ligand of the c-kit protooncogene product. In this study, we screened for mast cell-lineage involvement in 52 patients suffering from myeloid leukemias, myelodysplastic syndromes (MDS), systemic mastocytosis, or other diseases by probing for mast cell-related molecules (c-kit, tryptase, histamine, and MGF) and by analyzing kit ligand/MGF-independent growth of mast cells in long-term suspension culture. Of the 52 patients tested, 2 patients with refractory anemia with excess of blast cells in transformation and 1 patient suffering from chronic myeloid leukemia blast crisis (CML-BC) were diagnosed as mastocytic disease. These patients were characterized by complex chromosomal abnormalities, splenomegaly, high percentages of circulating metachromatic cells (5% to 25%), high levels of cellular tryptase (> 10 ng/10(5) peripheral blood mononuclear cells/mL) and a tryptase/histamine (ng:ng) ratio greater than 1. The metachromatic cells expressed the mast-cell-related surface antigen c-kit, but not basophil-related antigens (CD11b, CDw17). Furthermore, in these 3 patients, spontaneous, MGF-independent growth of mast cells along with spontaneous synthesis of tryptase was demonstrable in long-term culture. No autocrine production, paracrine production, or overproduction of MGF was found. The spontaneous growth of mast cells could neither be abbrogated by addition of monoclonal antibodies (MoAbs) to c-kit nor by MoAbs against MGF (< 5% inhibition), whereas factor (MGF)-dependent differentiation of mast cells in these patients could be abbrogated by MoAbs to c-kit or MoAbs to MGF (> 70% inhibition, P < .001). In addition, serum MGF levels in these patients were within the normal range and MGF could not be detected in cell-free culture supernatants. All 3 patients showed rapid progression of disease and had a survival time of less than 1 year. In conclusion, we describe a unique form of transformation in MDS and CML-BC characterized by mast cell lineage involvement and factor-independent differentiation of mast cells. This form of leukemic transformation has to be delineated from chronic myeloid leukemia with basophilia or basophil crisis, from primary mast cell leukemia, and from monocytic leukemias and myelodysplastic disorders associated with basophilia.

Acute Disease↗
PubMed1995

Human heart mast cells. Isolation, purification, ultrastructure, and immunologic characterization.

We have isolated, partially purified, and characterized the mast cells from human heart tissue. The histamine content of left and right ventricles and septum of hearts obtained from 25 patients undergoing heart transplantation was 5.4 +/- 0.6, 5.3 +/- 0.5, and 5.6 +/- 0.5 micrograms/g of wet tissue, respectively. Ultrastructural study of cardiac mast cells revealed scroll, crystal, and mixed granules, homogeneously dense granules, and lipid bodies in the cytoplasm. A mild collagenase digestion was used to disperse the heart mast cells; the average yield was 3.2 +/- 0.6% (range: 0.8 to 13.6%). The average histamine and tryptase content/heart mast cells was 3.3 +/- 0.2 pg (n = 25) and 24.2 +/- 4.3 micrograms/10(6) cells (n = 11), respectively. Survival of cardiac mast cells after overnight culture was 71.9 +/- 5.4% (n = 23). The purification of human heart mast cells can be brought from less than 0.1 to 12% by a combination of low-speed centrifugation over albumin (2%) solution and Percoll gradient. Viability as shown by trypan blue exclusion was greater than 90%. Heart mast cells released histamine in response to immunologic (anti-IgE, anti-Fc epsilon RI, and C5a) and nonimmunologic stimuli (recombinant human stem cell factor, A23187, and compound 48/80) but did not respond to substance P, FMLP, 12-O-tetradecanoylphorbol-13-acetate, or acetylcholine. There was a linear correlation between the percentage of release caused by anti-IgE and anti-Fc epsilon RI, whereas there was no correlation between the release caused by C5a and anti-IgE-mediated stimuli. Cross-linking with anti-IgE of IgE on heart mast cells induced the release of tryptase (10.1 +/- 2.1 micrograms/10(7) cells; n = 10) and the de novo synthesis of PGD2 (17.3 +/- 4.3 ng/10(6) cells; n = 10) and of leukotriene C4 (19.1 +/- 4.5 ng/10(6) cells; n = 10). There was a linear correlation between the percentage of histamine secretion and tryptase release (r = 0.67; p < 0.001) induced by cross-linking of Fc epsilon RI. similarly, there was a significant correlation between percentage of histamine secretion and PGD2 (r = 0.63; p < 0.001) and LTC4 (r = 0.64; p < 0.001) release. Immunoelectron microscopy demonstrated the presence of chymase in cardiac mast cells. Mast cells isolated from human heart can be a useful model with which to study the role of these cells and their mediators in cardiac anaphylaxis and cardiovascular diseases.

Cell Separation↗
PubMed1995

Heterogeneity of human mast cells based on cytokine content.

Human mast cells can be divided into two distinct phenotypes based on their content of neutral serine proteases, suggesting that they serve differing biologic and pathologic roles. Recently, it has been demonstrated that human mast cells are a source of several pleiotropic cytokines including IL-4, IL-5, IL-6, IL-8, and TNF-alpha, but not all mast cells contain all of these cytokines, suggesting that there is also functional heterogeneity with respect to cytokine expression. In this study, we have examined the relationship between mast cell neutral protease expression and cytokine content using immunohistochemistry. Bronchial mucosal biopsies from five normal subjects and five patients with allergic asthma, and nasal mucosal biopsies from five normal subjects and three patients with allergic rhinitis were embedded in glycol methacrylate. Sections (2 microns) were stained for IL-4, IL-5, and IL-6, adjacent to serial sections stained for tryptase and chymase. The distribution of cytokines among the tryptase+ chymase- mast cells (MCT) and tryptase+ chymase+ mast cells (MCTC) was examined by co-localization of cytokines to MCTC or MCT in serial sections using the camera-lucida. Although IL-4 was distributed among both mast cell phenotypes, it was expressed preferentially by the MCTC subset (overall 85% MCTC:15% MCT). In contrast, IL-5 and IL-6 were restricted almost exclusively to the MCT subset. Immunostaining of isolated skin mast cells (> 99% MCTC) supported these findings, with strong immunoreactivity present for IL-4 but very little for IL-5 or IL-6. These results indicate that in addition to exhibiting heterogeneity with respect to neutral protease content of the secretory granules, human mast cells are also heterogeneous with respect to cytokine content. This suggests that the biologic functions of MCTC and MCT cells differ as a result of their capacity to generate and release different cytokine profiles.

Adult↗
PubMed1994

Enhanced sensitivity of mdx mice to intramuscular injection of compound 48/80.

Species-specific differences in the inflammatory response, specifically with regard to mast cells, have been proposed to explain the phenotypic variation among dystrophin-deficient humans, and mdx mice (Gorospe et al., 1994). To test this hypothesis we have intramuscularly injected a mast cell secretogogue into both dystrophin-negative mdx and dystrophin-positive normal mice. Mast cell activity was determined by measuring the activity of mast cell tryptase, while creatine kinase activity was used to determine the course of muscle damage in vivo. Area of damage around the injection site was measured at autopsy, and used as an indication of relative sensitivity to the secretogogue effect of compound 48/80. Mdx mice exhibited more damage in response to intramuscular injection than normal control mice. In addition, mdx mice showed a substantial increase in plasma tryptase activity, followed by a large increase in muscle creatine kinase activity. On the other hand, dystrophin-positive normal controls injected with 48/80 liberated little CK or tryptase activity. These results are consistent with the hypothesis that species-specific differences in mast cell activity, or sensitivity to mast cell products could account for the variation in pathology seen in dystrophin-deficient animals.

Animals↗
PubMed1993

[Distribution of MCT and MCTC in nasal mucosae--relationship with formalin-sensitive mast cells and formalin-resistant mast cells].

The distributions of tryptase-positive, chymase-negative mast cells (MCT) and tryptase-positive, chymase-positive mast cells (MCTC) were examined in allergic and non-allergic nasal mucosae. Sequential double immunohistochemical staining with anti-chymase and anti-tryptase antibodies was carried out. Additionally, metachromatic cells were examined in formalin or Carnoy-fixed tissues. The main types of mast cells in the epithelium were MCT and formalin-sensitive mast cells (FSMC) and those in the lamina propria were MCTC and formalin-resistant mast cells (FRMC) in both allergic and non-allergic nasal mucosae. The densities of MCT and FSMC in the nasal epithelium were observed to be significantly higher in the allergic group than in the non-allergic group. The distributions of MCT and FSMC, MCTC and FRMC tended to be similar in the nasal mucosa. The immunohistochemical method offered some advantages such as a higher sensitivity and the possibility to make observations in one section. Recently, human mast cells have been classified as either MCT or MCTC. It seems that information of the distribution of MCT and MCTC and of FSMC and FRMC is useful in studying the organ specificity and functional heterogeneity of mast cells in allergic tissues such as those found in nasal allergy.

Adolescent↗
PubMed1993

[Alcohol-dependent mast cell activation in ulcer].

Numerous studies have shown that alcohol causes both acute and chronic damage to gastroduodenal mucosa. The methods of damage differ however, and experimental studies in animals have shown that the degranulation of mast cells in gastric mucosa causes acute hemorrhagic lesions after the consumption of alcohol. It is not known whether this mechanism also operates in man. The aim of the present study was therefore to evaluate whether there is a correlation between mast-cell activation, determined by assaying tryptase levels in gastric mucosa, and the consumption of alcohol in patients with ulcerative diseases. Thirty-one patients with cicatrized ulcerative lesions (13 gastric ulcers, 18 duodenal ulcers) were included in the study. Biopsies at the level of the gastric fundus and antrum and the duodenal bulb were performed in all patients to determine tryptase levels. Biopsy material was frozen and subsequently homogenized; the enzyme was assayed in the supernatant using a radioimmunometric method. The mean daily alcohol consumption was calculated in clinical terms for each patient over the past 5 years and patients were subdivided into non-drinkers and moderate (< 60 g alcohol/day) and excessive (> 60 g alcohol/day) drinkers. It was found that tryptase concentrations were higher in the fundus compared to the gastric antrum and duodenal bulb, irrespective of alcohol consumption both in patients with gastric ulcer and duodenal ulcer. The importance of mast cells in provoking alcohol-dependent damage was studied at a gastric level. Alcohol leads to their degranulation and therefore contributes to the formation of gastric lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1996

Cromolyn increases strength in exercised mdx mice.

Exercised mdx mice were used to evaluate the efficacy of two pharmacologic entities, cromolyn and compound 48/80. Beginning at 2 weeks of age, mdx mice were treated with either cromolyn (50 mg/kg/day), prednisone (2mg/kg/day), compound 48/80 (1mg/kg/day), or diluent vehicle. At 4 weeks of age, treated mice were subjected to twice weekly, forced treadmill running which has previously been shown to cause expressed weakness in mdx mice (Hudecki, Pollina et al., 1993). Strength was evaluated weekly through 6 weeks of age using a previously described "pull-test" procedure (Hudecki, Pollina et al., 1993). Serum creatine kinase (CK) and mast cell tryptase activities were evaluated from 6 week blood samples. There was a significant increase in strength in mdx mice treated with cromolyn (p < or = 0.05), while no significant increase in strength was found in mice treated with compound 48/80, or prednisone compared to vehicle controls. While no significant change in tryptase activity was found between treatments, CK activity was significantly increased in the cromolyn group compared to vehicle controls. However, when tryptase and CK were expressed as a combined factor (Tryp x CK), the cromolyn treated group was significantly different from all other groups. The results of this study suggest a possible use for cromolyn-like compounds in the treatment of Duchenne muscular dystrophy.

Aging↗
PubMed1997

Immunolocalization of bFGF in pterygia: association with mast cells.

PURPOSE: To examine the expression of basic fibroblast growth factor in pterygia and determine whether mast cells contain basic fibroblast growth factor (bFGF) in this disease process. METHODS: Formalin-fixed paraffin-embedded tissue samples of pterygia (n = 14) were used to study the expression of bFGF with immunohistochemistry. Seven samples were also double labeled with specific antibodies to bFGF and tryptase (a specific mast cell marker). RESULTS: In all tissue samples examined, bFGF was specifically localized in blood vessels, epithelium, and a subset of connective tissue cells. The majority of bFGF-positive connective tissue cells were also tryptase positive (90.4 +/- 3.6%). Nearly all the tryptase-positive cells (mast cells) in the pterygia tissues coexpressed bFGF (98 +/- 1.5%). CONCLUSIONS: These findings suggest that bFGF may have biologic effects on the epithelium and blood vessels in pterygia, with epithelial and endothelial cells as a possible source. In addition, mast cells contain bFGF in the pterygia tissues examined in this study. The mast cells may serve as an additional source of bFGF, possibly modulating a variety of cell types as well as the extracellular matrix in pterygia.

Adult↗
PubMed1998

Dendritic mast cells in the human nasal mucosa.

Human mast cells can be divided into two subtypes: MCTC cells, which contain tryptase and chymase, and MCT cells, which contain tryptase only. Herein we have used a combination of histamine, tryptase and chymase immunohistochemistry as a novel approach to the study of mast cells. Using this technique, we have discovered a new type of MCTC mast cell in biopsies of the nasal mucosa from healthy subjects and allergic patients. These mast cells have histamine-positive, dendrite-like cellular processes. Some cells have only one slender process, whereas other cells have several long processes extending from different parts of the cell body. Some of the cellular processes divide into two or three terminal branches, and histamine is sometimes found in small swellings along the course of the processes. Our findings contribute new aspects to the concept of mast cell heterogeneity. Thus, human mast cells may vary not only with respect to mediator content, but also with respect to gross morphologic features such as the presence of dendrite-like cellular processes. The recognition of this extreme heterogeneity may be an important step toward a better understanding of mast cell biology.

Adult↗
PubMed1996

Quantitative histochemical analysis of mast cells and sensory nerves in psoriatic skin.

To study the elements of neurogenic inflammation in psoriatic skin, morphological contacts were examined between mast cells and sensory nerves containing the neuropeptides substance P (SP), calcitonin gene-related peptide (CGRP) or vasoactive intestinal polypeptide (VIP). Because mast cells in psoriatic lesions appear in great numbers at the basement membrane (BM) zone, neuropeptide-mast cell contacts with the BM were also counted. A double stain for active mast cell tryptase and the neuropeptides was applied and the contacts were quantitated morphometrically. Sensory nerve-mast cell contacts were also studied three-dimensionally with a confocal laser scanning microscope. Increases in the contact values of SP and CGRP with mast cells, as well as with the BM, were obtained in developing (1-3 weeks) lesions when compared with their non-lesional controls. This increase reached statistical significance in mature lesions. In contrast, the corresponding contact values for VIP were decreased. By confocal microscopy, a close association between mast cells and sensory nerves was observed in the lesional dermis. Since tryptase is known to degrade CGRP but not SP, neurogenic stimuli, mainly via SP, can result in degranulation of mast cells, which release substances to enhance inflammation. At the BM zone in psoriatic lesions, the numerous mast cells loaded with tryptase can promote degradation of BM components and allow entry of various mediators to interact with keratinocytes.

Adult↗
PubMed2000

Cutaneous protease activity in the mouse ear vesicant model.

Tissue homogenates from mouse ear skin exposed to sulfur mustard (HD, which is a military designation and probably originated from a World War I slang term 'Hun Stuff') were assayed for serine and cysteine protease activities. Enzyme activity was measured using synthetic chromogenic thioester and fluorogenic 7-amino-4-methylcoumarin (AMC) substrates. The tissue samples were obtained from animals (n = 6) at 3, 6, 12 and 24 h post-exposure from the right ear (HD exposed), whereas control samples were obtained from the left ear (treated only with dichloromethane vehicle). The samples of naive control (left and right ear) were obtained from animals that received no HD treatment (n = 3). Elastase activity was assayed with t-butyloxycarbonyl-Ala-Ala-Ala-thiobenzylester, tryptase activity with benzyloxycarbonyl-Arg-AMC and benzyloxycarbonyl-Arg-thiobenzylester, chymase activity with succinylAla-Ala-Pro-Phe-thiobenzylester and succinyl-Ala-Ala-Pro-Phe-AMC, cathepsin B activity with benzyloxycarbonyl-Arg-Arg-AMC, cathepsin H activity with Arg-AMC and calpain activity with succinyl-Leu-Tyr-AMC. The HD-exposed skin homogenates obtained at 12 and 24 h post-exposure had higher elastase activity (670% and 1900% increase) than control samples. For tryptase and calpain activities, only HD-exposed skin homogenates at 24h post-exposure showed higher activities (220% and 170% increase) when compared to the control. No differences from control were observed for HD-exposed skin obtained at 3 and 6 h post-exposure for elastase, tryptase and calpain activities. Generally, both unexposed and HD-exposed skin had distinct cathepsin B and cathepsin H enzyme activities and small chymase activity. Enzymatic assays were also performed for other serine, cysteine and metalloproteases. These data document that proteases are involved in HD skin injury and continued assessment of proteolytic activity should be useful for identifying effective antiproteases with therapeutic use in reducing or eliminating tissue injury caused by HD cutaneous exposure.

Animals↗
PubMed2006

Development of testicular inflammation in the rat involves activation of proteinase-activated receptor-2.

Mast cells are involved in early events crucial to inflammation and autoimmune disease. Recently, proteinase-activated receptor-2 (PAR(2)), a G-protein coupled receptor important to injury responses, was shown to be activated by mast cell tryptase. To investigate whether mast cells and PAR(2) are involved in the development and/or aggravation of testicular inflammation, we studied acute and chronic inflammatory models in the rat. In normal testes, PAR(2) was detected immunohistochemically in macrophages, in peritubular cells (PTCs) and in spermatid acrosomes. In experimentally induced autoimmune orchitis (EAO), PAR(2) was strongly upregulated in macrophages and peritubular-like cells, forming concentric layers around granulomas. Mast cells increased 10-fold in number, were more widely distributed throughout the interstitial tissue, and were partially degranulated. Isolated PTCs expressed functional PAR(2), responded to PAR(2) activation by phosphorylating extracellular signal-regulated kinases 1/2 (ERK1/2) and activating protein kinase c, and increased intracellular Ca(2+) concentrations as well as monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta(2) (TGFbeta(2)), and cyclooxygenase-2 (COX-2) mRNA expression. Expression of these inflammatory mediators, together with iNOS, also increased significantly in testes 50 days after EAO. In vivo, expression of cytokines and inflammatory mediators was upregulated after injection of recombinant tryptase (MCP-1, TGFbeta(2), and COX-2) and a specific PAR(2) peptide agonist (MCP-1, TGFbeta(2)) in the testis after 5 h. These results suggest that PAR(2) activation elicited on PTCs by mast cell tryptase contributes to acute testicular inflammation and that this pathogenetic mechanism may also play a role in autoimmune orchitis.

Acute Disease↗
PubMed2002

Cytokines regulate development of human mast cells from hematopoietic progenitors.

Combination of stem cell factor (SCF) and interleukin-6 (IL-6) significantly promoted proliferation of human mast cells from cord blood CD34+ cells. Most of the cells, cultured in the presence of SCF and IL-6 for 10 weeks, expressed c-kit and contained a significant amount of histamine and tryptase and a low amount of chymase. Both tryptase-positive chymase-negative mast cells (MC(T)) and tryptase-positive chymase-positive mast cells (MC(TC)) were found in the same colony derived from a single cord blood CD34+ cell, suggesting that MC(T) and MC(TC) develop from common precursor cells. Single-cell culture of CD34+ cells revealed that committed mast cell progenitors are included in CD34+CD38+HLA-DR- cells. IL-4 significantly enhanced high-affinity immunoglobulin E (IgE) receptor (FcepsilonRI) alpha-chain messenger RNA expression and induced FcepsilonRI on SCF-dependent cord blood-derived human mast cells, resulting in high histamine-releasing activity upon cross-linking of FcepsilonRI. Another factor that up-regulated FcepsilonRI was IgE, and a combination of IL-4 and IgE markedly augmented FcepsilonRI expression on the mast cells. IL-4 and IgE may enhance FcepsilonRI expression by distinct mechanisms; IL-4 promotes FcepsilonRI alpha-chain gene transcription and thus increases alpha-chain protein synthesis in the cells, whereas the binding of IgE may anchor the FcepsilonRI on the cell surface, resulting in suppression of internalization of FcepsilonRI. Mast cells are progeny of hematopoietic stem cells. Recent discovery of a xenotransplantation model revealed that human hematopoietic stem cells can proliferate and differentiate into mature mast cells in the mouse skin 3 months after transplantation of human cord blood CD34+ cells, suggesting that this model may pave the way to clarification of the functions of human mast cells in vivo.

Animals↗
PubMed1997

Histamine release during cardiopulmonary bypass in neonates and infants.

PURPOSE: Histamine release has been previously documented in adults and children during cardiopulmonary bypass (CPB). It has not been studied in neonates nor during deep hypothermic circulatory arrest (DHCA). Histamine effects could explain many perioperative complications of congenital cardiac surgery such as dysrhythmias and massive oedema. Therefore, documentation of histamine release in the perioperative period is of clinical importance. The source of histamine can be determined by measurement of tryptase which is released with histamine from mast cells but not basophils. METHODS: Blood samples for histamine and tryptase were taken before and after specific events eg. cross-clamp removal, during anaesthesia and CPB in 14 infants and seven neonates undergoing complex congenital heart repairs and were analysed by commercial radioimmunoassays. Haemodynamic variables and pre and post-op weights were recorded to look for correlation between pathophysiological events and histamine release. RESULTS: Histamine concentration decreased at the start of bypass (0.69 to 0.38 ng.ml-1 at five minutes, (P < .005). There were no changes associated with DHCA and a small rise with reventilation (P < 0.02). Histamine concentration was lower in neonates than in infants (P < 0.05) during CPB. Plasma histamine and tryptase concentrations did not correlate, suggesting histamine release was from basophils and not from mast cells. Haemodynamic variables did not correlate with histamine concentrations. CONCLUSION: There was no major histamine release during CPB in infants and neonates. There was no relationship between histamine concentrations and clinical variables. Histamine released during CPB appears to come from basophils and may be a function of age.

Age Factors↗
PubMed1990

A biochemical study of serine proteinase activities at local gingival tissue sites in human chronic periodontitis.

Serine proteinases have the potential to influence the degradation of connective tissue in chronic periodontitis, which may progress episodically at individual tooth sites. Elastase-, chymotrypsin- and tryptase-like proteinase activity in homogenized gingival tissue were measured using, respectively, the selective peptide substrates MeOSuc-Ala-Ala-Pro-Val-AFC. MeOSuc-Phe-Pro-Phe-AFC and Z-Ala-Arg-Arg-AFC. Each tooth site was assayed separately and divided, where appropriate, into gingival tissue and granulomata. Elastase-like activity was detected in only about half of the sites and with large variations. Chymotrypsin-like activity decreased with increasing pocket depth, clinical attachment level, gingival index and gingival bleeding index. Tryptase-like activity did not vary consistently with clinical measures. Chymotrypsin- and tryptase-like proteinase activity were much higher in gingival tissue than in granulomata. These effects are best explained by the likely influence (or lack of influence) of the endogenous serum and tissue inhibitors of serine proteinases, the different cellular origins of the enzymes, and their relative affinities for their substrates.

Adult↗
PubMed1990

The mast cell as an effector of connective tissue degradation: a study of matrix susceptibility to human mast cells.

The susceptibility of connective tissue elements to degradation by human mast cells was explored using purified mast cell tryptase and sonicated mast cell preparations. The R-22 strain of smooth muscle cells from rat heart was used for preparation in vitro of a labelled anchored matrix. Digestion of 11.9 +/- 1.2% (n = 5) of this matrix was observed after overnight incubation with the mast cell sonicates. Pretreatment of the sonicate with a tryptase inhibitor TLCK reduced the digestion by 42%. Digestion of 12 +/- 1% (n = 4) of the matrix was observed with purified tryptase. The susceptible substrate within this anchored insoluble matrix resided in the glycoprotein compartment as defined by enzymatic characterization of the residual matrix. Mast cells may play a role in mediating connective tissue degradation through the release of proteases specifically synthesized by this cell.

Animals↗