Proliferation and transepithelial migration of mucosal mast cells in interstitial cystitis.

The distribution and abundance of mast cells, as well as their fixation, staining and ultrastructural properties, were studied in the urinary bladders of 16 patients with interstitial cystitis (IC) and in 14 normal subjects. Tissues were fixed in both standard formaldehyde solution and a special fixative, IFAA, optimized for the preservation of mucosal mast cells. An expansion of two distinct mast cell populations was observed in IC. One of these, comprising formaldehyde-sensitive cells, was found only in the mucosa underlying lesions of IC. They were most numerous in the lamina propria but were also frequent in the epithelial layer as well as in the bladder washings, indicating a migratory capacity for these cells. The other mast cell population was visualized equally well irrespective of fixation and staining procedure. In control subjects, such cells were found both in the lamina propria and detrusor muscle, but not in the epithelium nor in bladder washings. In lesions of IC they were increased in the detrusor muscle only. Both types of mast cell contained granules with the highly characteristic lamellar arrays and scrolls, distinguishing human mast cell granules from those of blood basophils. The proliferation and intraepithelial distribution of mucosal mast cells are unusual findings, but prominent features of helminth responses and human mucosal allergic reactions. These findings thus suggest that the mucosal mast cell-IgE system may be involved in the pathogenesis and/or aetiology of IC.     

Histamine and mucosal mast cells in gluten enteropathy

Coeliac disease is a malabsorptive disorder caused by intolerance to gluten and is characterized by a remodelling of the intestinal mucosa including villus atrophy, crypt hyperplasia and net increase of mucosal volume. Changes of the number of mucosal mast cells (MMCs) in coeliac mucosa has recently been reported, suggesting that the mast cell activity could have a pathogenetic role in gluten enteropathy. MMCs located solely in the lamina propria are the main repository for small-gut mucosal histamine.A consecutive prospective study was designed to study the histamine content, MMC numbers, and the relative volume of lamina propria in intestinal biopsies from adult patients suffering from unexplained diarrhea and/or malnutrition. Histamine was measured by a HPLC-method, the number of MMC was counted after long toluidine-blue staining, and the relative volumes of lamina propiria and epithelium were estimated morphometrically. The findings were correlated to the histopathological appearance of the mucosa. As compared to controls the histamine content increased by 80% and MMC numbers by about 60% in the coeliac mucosa. There was also a correlation between MMC numbers and histamine content for both normal and coeliac mucosae (r=0.81). The morphometric estimation of the relative volumes of epithelium and lamina propria revealed that the lamina-propria compartment was increased by approximately 40% in coeliac mucosa.Taking the changes in compartmental volumes of the remodelled coeliac mucosa into account, our results suggest that the histamine content and MMC population were significantly increased. MMC and MMC-associated histamine may therefore be involved in the pathogenesis of gluten enteropathy.Supported by the Swedish Medical Research Council, Project Nos. 2235 and 5942.     

Activation of bladder mast cells in interstitial cystitis.

Interstitial cystitis (IC) is a sterile, inflammatory bladder condition characterized by urinary frequency and urgency, as well as burning and suprapubic pain, which occurs more frequently in women who may suffer for years before diagnosis. An increased number of mast cells have been associated with IC, but the published reports are inconclusive and often conflicting. Human bladder biopsies were analysed blindly for the degree of activation of mast cells in control and IC patients. It was found that mast cells from IC patients averaged as high as 34 cells/mm2 as compared to less than 16/mm2 in controls. Electron microscopy revealed that over 90% of mast cells from IC patients were activated to various degrees. It is concluded that mast cell activation is a pathologic characteristic for IC.     

Histamine releasers and rat mast cells

The release of histamine from rat tissues rich in mast cells, induced by antigen, concanavalin A, dextran, compound 48/80, A 23187, phosphatidic acid and chlortetracycline, has been compared with that from isolated peritoneal mast cells of rats. Whereas most of the agents were more active than dextran in in vitro experiments, the reverse was found when they were injected intradermally into the skin, or subcutaneously into the paws. In fact, A 23187 and chlortetracycline (both calcium ionophores), as well as phosphatidic acid (another non-cytotoxic releaser), failed to release significant amounts of histamine when injected into the animal. Thus, the experimental conditions in which comparisons of the activities of histamine releasers are made should always be stated.     

Histamine release from human pulmonary mast cells

The enzyme collagenase was used to disperse human lung into its component cells. The resulting cell suspensions containedcirca 8% mast cells and were used for studies of mediator release without further purification. They exhibited a low (circa 7%) spontaneous release of histamine. They could be sensitized passively and released histamine upon challenge with anti-human IgE. They responded to concanavalin A but not to dextran. Phosphatidyl serine did not potentiate the release induced by these agents. The calcium ionophores, A23187 and ionomycin, both elicited histamine release. The cells were refractory to the action of the basic releasers 48/80 and peptide 401 (MCD-peptide). These results indicate marked differences between human pulmonary mast cells and the more widely used rat peritoneal mast cells.     

Granule maturation in mast cells: Histamine in control

Mast cells are derived from committed progenitors that originate in the BM. They mature into histochemically distinguishable, metachromatic mast cells containing numerous cytoplasmic secretory granules. Accumulating evidence demonstrates that mast cell granule maturation is very tightly regulated by many factors including different granule components such as proteoglycans. In this issue of the European Journal of Immunology, Nakazawa et al. [Eur. J. Immunol. 2014. 44 : 204–214] highlight a role for mast cell derived histamine as another factor critical for mast cell maturation. Using histidine decarboxylase (HDC) deficient mice that are unable to make histamine, they show poorly formed secretory granules and decreased secretory granule protease expression in peritoneal mast cells. Co‐culturing BM‐derived mast cells with fibroblasts normally drives granule maturation, but HDC‐deficient BM‐derived mast cells fail to do so. Exogenously provided histamine partly restores granule differentiation as evidenced by increased tryptase and chymase activity, and this is histamine receptor type H₄‐dependent. However, H₄‐deficient mice have intact granule formation in peritoneal mast cells, suggesting that when HDC is functional, the intrinsic histamine production is sufficient for most granule maturation processes and H₄ is dispensable. This study highlights the role of histamine in the regulation of mast cell maturation, although the cytosolic target remains unknown.     

Gastric mucosal mast cells in atopic subjects

Intragastral allergen provocation under endoscopic control (IPEC) allows direct observation of gastric mucosa reactions after contact with inhalant allergens that reach the stomach. We selected patients with proved atopy to Parietaria but without clinical and endoscopic signs of gastric disease, and we tested them with the specific inhalant allergen during IPEC, recording gastric macroscopic reaction and mucosal mast-cell changes in biopsy specimens. All atopic patients showed visible changes in gastric mucosa quantified as IPEC score. Mast-cell numbers detected in atopic patients (135.4 ± 102.6/mm² of stromal area) were significantly higher than in nonatopic subjects (59.8 ± 25.4/mm²; P <0.03) and were positively correlated to atopic IPEC score ( P <0.01). In addition, 6/12 atopics who had both higher mast-cell counts and IPEC score showed an intraepithelial distribution of gastric mast cells which displayed ultrastructural features of partial degranulation. It is likely that changes observed in our patients with allergy to Parietaria reflect a subclinical activation of mast cells in the gastric mucosa.     

Histamine release from mast cells of the rat

The relative activities of 12 agents inducing anaphylactoid oedema in the paws of two types of genetically different rats have been compared with those inducing histamine release from isolated peritoneal cells. Four groups were identified - group 1 where activities were much higher in R rats than in NR rats, doses in vivo being in all cases much lower than those required in vitro; group 2 where activities were similar in the two types of rat, doses in vivo again being relatively much lower; group 3 where activities were similar in both types of rat though doses in vivo were relatively high; group 4 where activities were similar in both types of rat, but doses in vivo were relatively extremely high. Only the activities of releasers in groups 1, 2 and 3 (represented by dextran, concanavalin A and antigen) required calcium ions in vitro and were potentiated by phosphatidyl serine; they were potentiated in vivo by insulin and inhibited by glucose.     

Histamine secretion from mast cells stimulated with somatostatin

Histamine release from isolated mast cells stimulated with somatostatin resembled that induced by other basic agents. The process was rapid, independent of added calcium or phospholipids, non-cytotoxic, species and tissue specific, not mediated through cell-fixed antibodies or glucoreceptors, and inhibited by antagonists of the polyamine receptor. Somatostatin and other polycations may then act through a common receptor or binding site on the mast cell membrane.     

Histamine release from dispersed human intestinal mast cells

To study the human intestinal mast cell of children and adults, we combined a sensitive glassfibre-based histamine assay with the enzymatic and mechanical dispersion of surgical specimens or mucosal biopsies. The method yields between 1.2 x 10(3) to 4.6 x 10(3) mast cells/mg tissue constituting 1.2% to 5.3% of total cell count. The mast cell yield, however, depends on the intestinal tissue specimen used for dispersion. Aliquots containing 1500 mast cells per sample are sufficient for measuring significant amounts of histamine (greater than or equal to 0.15 ng histamine per sample), thus making it possible, to carry out approximately 75 tests for four mucosal biopsies of 10 mg each. The intestinal mast cell releases histamine in a dose-dependent manner on challenge with anti-IgE (6-600 U/ml), ionophore A23187 (0.25-1.0 microM), and Concanavalin A (0.7-25.0 micrograms/ml). The histamine release shows interindividual variation with a net histamine release between 0 to 2.5 ng/samples dependent on the secretatogue. In general, it is not necessary to passively sensitize the mast cells to obtain a sufficient histamine release response to anti-IgE challenge, indicating the presence of intact and functional cell-bound IgE. However, it is shown that four of 10 non-atopic intestinal mast cell samples could be passively sensitized with human plasma containing either mite- or grass-specific IgE without stripping off the IgE first. This indicates the presence of free and preserved Fc-receptors on the dispersed mast cells in some subjects. In addition, it is found that the phorbolester TPA increases the histamine release response to A23187 and turns anti-IgE non-responding mast cells into responding mast cells, but TPA alone at 2 to 16 ng/ml has no histamine releasing effect. In patients with anti-IgE responding mast cells no additional effect of TPA is seen. Finally, no substantial differences between mast cells of children and adults are demonstrated.     

Histamine secretion from mast cells stimulated with ATP

Adenosine 5-triphosphate (ATP) induced a non-cytotoxic, calcium-dependent release of histamine and prostaglandin D₂ from rat serosal mast cells. The effect was tissue and species specific. In particular, tissue mast cells from the guinea pig and were totally unresponsive. The release evoked by the nucleotide was unaffected by antiasthmatic chromones but was inhibited by structurally related flavonoids and by cAMP-active drugs. Secretion was blocked both by the P_2Y-purinoceptor antagonist reactive blue 2 and the P_2x-antagonist suramin, whereas the P₂-agonists 2-methylthio ATP, ,-and,-methylene ATP were inactive. These findings indicate that ATP acts through a novel purinoceptor or binding site which is present on certain types of mast cells.     

Histamine secretion from mast cells stimulated with bradykinin

Bradykinin and a range of peptide analogues induced a dose-dependent release of histamine from rat peritoneal mast cells. The characteristics of the release were not consistent with the involvement of defined bradykinin receptors but indicated that the peptide acted through the putative mast cell polyamine receptor. Consistently, the effect of bradykinin was largely confined to serosal mast cells of the rat and hamster, while human histaminocytes were essentially unresponsive. These data do then not support a general role for kinin-induced activation of mast cells in human allergic disease.     

Histamine release from nasal mucosal mast cells in patients with chronic hypertrophic non-allergic rhinitis,after parasympathetic nerve stimulation

The vidian nerve provides the main parasympathetic nerve supply to nasal respiratory and maxillary sinus mucosa, and its electrical stimulation causes apparent secretory and vasodilatatory effects in animals.The present investigation was carried out in 8 patients with chronic hypertrophic non-allergic rhinitis (C.H.N.A.R.) undergoing therapeutic vidian nerve resection. The vidian nerve was electrically stimulated before the resection. Samples were taken from nasal sinus mucosa for histamine determination and microscopical observation before and after the stimulation period. Vidian nerve stimulation causes a significant decrease in histamine content and mast cell density in the mucosa sample, differentially influenced by eserine and atropine pretreatment.     

Human gastric mucosal mast cells are chondroitin sulphate E-containing mast cells.

Our recent identification of chondroitin sulphate E-containing mast cells (E-MC) in the human colonic mucosa is extended here to the human gastric mucosa by using a combination of both biochemical and immunochemical approaches. Most of the mast cells in human gastric biopsies, which were located mainly around small blood vessels in the submucosa, showed various degrees of degranulation and were granular when stained by monoclonal antibody against chondroitin sulphate proteoglycan. The human gastric mucosa biopsies incorporated (35S)-sulphate into proteoglycans. Cells in the tissues which were histamine-positive also incorporated (35S). The 35S proteoglycans, which were either left associated with the tissue or released into the medium, were found not to be heparin but chondroitin sulphate E. Incubation of the human gastric mucosa biopsies in the presence of anti-human IgE revealed significant enhancement in the release of both (35S)-chondroitin sulphate E proteoglycan and histamine.     

Histamine releasability of basophils and skin mast cells in chronic urticaria

In order to clarify the pathogenetic role of basophils and mast cells in chronic urticaria, histamine and leukotrienes (LT) C₄ release was examined in washed mixed leukocytes (n=8) and skin mast cells (n=5) from patients with chronic urticaria and compared with the same cells from normal controls (n=9). Anti-IgE-stimulated basophil histamine release was significantly reduced in urticaria patients (median 2.9% vs 15.1% in normal controls), whereas histamine release to A23187, FMLP, and PAF, as well as anti-IgE-induced LTC₄ release, showed no differences in both groups. In contrast, anti-IgE-stimulated skin mast cells from urticaria patients reacted similarly to those of controls (median histamine release 11.4% vs 14.2% in normal controls). Pretreatment of the cells with interleukin (IL)-3 upregulated responsiveness of basophil histamine release to anti-IgE in urticaria patients (median histamine release 14.3%), but pretreatment with the H₂-antagonist cimetidine showed no effect. These data show that reduced basophil histamine releasability in chronic urticaria is not H₂ mediated. It is a stimulus-, mediator-, and cell type-restricted phenomenon that can, at least partially, be reversed in the presence of the cytokine IL-3.     

Local and systemic factors regulating mucosal mast cells

The contributions of local and systemic factors to the regulation of mucosal mast cells and globule leukocytes have been examined in the rat. Nippostrongylus brasiliensis has been used to provide a potent immunological stimulus for mucosal mast cell hyperplasia and the roles of intestinal and extraintestinal sensitization observed by comparison of the gut mast cell responses to larval and adult worm infestations. Systemic effects of adult worm infestations have been examined in isolated Thiry-Vella loops of intestine. It is concluded that the extraintestinal phase of larval infestation is not obligatory for a gut mast cell response and that mast cell hyperplasia and globule leukocyte formation are not dependent on direct contact with the parasite or its products. The dissemination of the mast cell response and the general significance of the results are discussed.     

Bone marrow origin of mucosal mast cells

Infection with the intestinal parasite Nippostrongylus brasiliensis stimulates an accumulation of mucosal mast cells (MMC) in the villi of the small intestine of normal but not athymic or W/Wv anemic mice. W/Wv mice are congenitally deficient in both MMC and skin and connective tissue mast cells (CTMC). Athymic mice have normal or elevated numbers of CTMC but are severely deficient in MMC. CTMC derive from the bone marrow. To determine the origin of MMC, athymic and W/Wv mice were given various hematopoietic or lymphoid tissues from normal littermate or beige mice and the MMC response to N. brasiliensis infection was evaluated. The MMC defect in athymic mice was repaired by grafts of thymus cells, thymus gland, or spleen cells, but not by bone marrow cells or anti-Thy 1-treated bone marrow or spleen cells. The MMC and CTMC defects of W/Wv mice were repaired by grafts of bone marrow, spleen cells, or anti-Thy 1-treated bone marrow or spleen cells. Neither the MMC nor the CTMC defect in W/Wv mice was repaired by grafts of thymus cells or thymus glands. These results indicate the following, MMC, like CTMC, derive from the bone marrow and not from the thymus. MMC require a thymic influence for development. Athymic mice possess bone marrow precursors for both MMC and CTMC but lack a thymus-dependent component necessary for MMC development. W/Wv mice lack both MMC and CTMC mast cell precursors but possess the thymus-dependent component required for MMC development.     

Histamine release from saponin-permeabilized rat mast cells by calcium

The first effect of receptor activation on the mast cell surface, initiating histamine secretion, is an increase in the cytosol Ca²⁺ concentration. It should then be possible to induce histamine secretion by calcium alone, if the calcium permeability of the cell membrane could be increased without any significant interference with the physiological cell functions. This was achieved in the present study by adding low concentrations of saponin (0.005% and 0.001% w/v) to the medium. When calcium was added to the saponinpermeabilized cells, around 40% histamine release occurred with 0.25 mM extracellular calcium (free Ca²⁺ 0.15 mM). The release was inhibited by antimycin A (1 M). Transmission electron microscopy showed formation of vacuoles containing granules stripped of their membranes, which characterize a secretory response. The observations are consistent with a limited increase in the calcium permeability of the cell membrane for a brief period. There was apparently an increase in the cytoplasmic calcium concentration, which acted through calmodulin, since the histamine release induced by calcium from the permeabilized mast cells could be inhibited by a calmodulin-antagonist, mepacrine (10–30 M).     

组胺对人结肠肥大细胞类胰蛋白酶释放的调节作用

探讨组胺对人结肠肥大细胞类胰蛋白酶释放的调节作用。经酶消化后获取人结肠组织肥大细胞,激发后行多种干预实验。用酶联免疫吸附试验法测定类胰蛋白酶。结果发现组胺可诱导人结肠肥大细胞释放类胰蛋白酶,浓度为100μg/L时组胺释放量最大,为基础值的3．5倍。浓度为10μg/L时对人肥大细胞的刺激强度与10mg/L的抗IgE抗体相似。组胺的作用从加样后10s开始,5min后完成。百日咳毒素和抗霉素A联合2．脱氧-D-葡萄糖可显著抑制组胺诱导人结肠肥大细胞释放类胰蛋白酶。100及1000μg/L的组胺与抗IgE抗体或离子载体钙同时加入细胞中,诱导类胰蛋白酶释放的能力低于组胺单独作用组。结论为组胺可激活人结肠肥大细胞,还以自身放大机制调节肥大细胞的脱颗粒过程。