Effects of N-(3',4',5'-Trimethoxycinnamoyl) ortho-Aminobenzoic Acid on Antigen-induced Contraction of Guinea-pig Ileum and the Degranulation of and Histamine Release from Mast Cells

N-(3′,4′,5′-Trimethoxycinnamoyl)ortho-aminobenzoic acid(TOA),at the concentration of 80μg/ml,significantly inhibited the antigen-induced contraction of ileum isolated from the actively sensitized guinea-pig.At the concentrations of 25 and 50μg/ml, TOA inhibited homocytotropic antibody-mediated degranulation of mast cells in the rat mesentery,and also inhibited anaphylactic histamine release from rat peritoneal mast cells.

HISTOCHEMICAL TECHNIQUES IDENTIFYING MAST CELLS IN PIG,CATTLE AND SHEEP

Carnoy′s fluid and neutral buffered formalin(NBF)have been proved to be good fixatives for preservation of mast cells in pig,cattle and sheep except NBF blocked staining of most porcine mast cells,especially those located in intestinal mucosa(MMC)and in thymus medulla(TMMC). Both toluidine blue and Alcian blue were the excellent stains generally,but Alcian blue stained more porcine mast cells than did toluidine blue( P <0 01). Staining with toluidine blue of a wide pH range(from 0 1 to 7 0)showed that porcine mast cells were not very pH dependent,but the dye at pH 0 5 seemed to have the strongest affinity for all mast cells in pigs and it was also suitable for bovine and ovine mast cell staining. In the three species,unlike in rodents,the Alcian blue method did not distinguish between mast cells in the intestinal mucosa(MMC)and those in the connective tissue of the intestinal submucosa,tongue and skin(CTMC). Porcine CTMC,but not MMC,fluoresced strongly when stained with berberine sulphate or with a mixture of berberine sulphate and acridine orange. It suggested that porcine CTMC contained heparin proteoglycan.

Mucosal mast cells are pivotal elements in inflammatory bowel disease that connect the dots:Stress,intestinal hyperpermeability and inflammation

Mast cells (MC) are pivotal elements in several physiological and immunological functions of the gastro- intestinal (GI) tract. MC translate the stress signals that has been transmitted through brain gut axis into release of proinflammatory mediators that can cause stimulation of nerve endings that could affect afferent nerve terminals and change their perception, affect intestinal motility, increase intestinal hyperpermeability and, in susceptible individuals, modulate the inflammation. Thus, it is not surprising that MC are an important element in the pathogenesis of inflammatory bowel disease and non inflammatory GI disorders such as IBS and mast cell enterocolitis.

Pancreatic and pulmonary mast cells activation during experimental acute pancreatitis

AIM:To study the activation of pancreatic and pulmonary mast cells and the effect of mast cell inhibition on the activation of peritoneal and alveolar macrophages during acute pancreatitis.METHODS:Pancreatitis was induced by intraductal infusion of 5% sodium taurodeoxycholate in rats.The mast cell inhibitor cromolyn was administered intraperitoneally(i.p.) 30 min before pancreatitis induction.The pancreatic and pulmonary tissue damage was evaluated histologically and mast cells and their state of activation were evaluated.Peritoneal and alveolar macrophages were obtained and the expression of tumor necrosis factor α was determined.Myeloperoxidase activity was measured to evaluate the effect of mast cell inhibition on the progression of the inflammatory process.Finally,the effect of plasma on cultured mast cells or macrophages was evaluated in vitro.RESULTS:The mast cell stabilizer signif icantly reduced inflammation in the pancreas and lung and the activation of alveolar macrophages but had no effect on peritoneal macrophages.Mast cell degranulation was observed in the pancreas during pancreatitis but no changes were observed in the lung.Plasma from rats with pancreatitis could activate alveolar macrophages but did not induce degranulation of mast cells in vitro.CONCLUSION:Pancreatic mast cells play an important role in triggering the local and systemic inflammatory response in the early stages of acute pancreatitis.In contrast,lung mast cells are not directly involved in the inflammatory response related to pancreatic damage.

Probiotic Lactobacillus rhamnosus downregulates FCER1 and HRH4 expression in human mast cells

AIM:To investigate the effects of four probiotic bacteria and their combination on human mast cell gene expression using microarray analysis.METHODS:Human peripheral-blood-derived mast cells were stimulated with Lactobacillus rhamnosus (L.rhamnosus) GG (LGG),L.rhamnosus Lc705 (Lc705),Propionibacterium freudenreichii ssp.shermanii JS (PJS) and Bifidobacterium animalis ssp.lactis Bb12 (Bb12) and their combination for 3 or 24 h,and were subjected to global microarray analysis using an Affymetrix GeneChip Human Genome U133 Plus 2.0 Array.The gene expression differences between unstimulated and bacteria-stimulated samples were further analyzed with GOrilla Gene Enrichment Analysis and Visualization Tool and MeV Multiexperiment Viewer-tool.RESULTS:LGG and Lc705 were observed to suppress genes that encoded allergy-related high-affinity IgE receptor subunits α and γ (FCER1A and FCER1G,respectively) and histamine H4 receptor.LGG,Lc705 and the combination of four probiotics had the strongest effect on the expression of genes involved in mast cell immune system regulation,and on several genes that encoded proteins with a pro-inflammatory impact,such as interleukin (IL)-8 and tumour necrosis factor alpha.Also genes that encoded proteins with anti-inflammatory functions,such as IL-10,were upregulated.CONCLUSION:Certain probiotic bacteria might diminish mast cell allergy-related activation by downregulation of the expression of high-affinity IgE and histamine receptor genes,and by inducing a pro-inflammatory response.

Hirschsprung's disease:Is there a relationship between mast cells and nerve fibers?

AIM:To define the topography of mast cells and their numbers in cases of Hirschsprung's disease(HD)and non-HD,assess neural hypertrophy using imaging software and to study the relationship between mast cells and nerve fibers.METHODS:HE stained sections of 32 cases of chronic constipation in the age group of 0-14 years were reviewed for ganglion cells.AChE staining was performed on frozen sections of colonic and rectal biopsies.Based on their findings cases were divided into HD and non-HD and mast cells stained by toluidine blue were evaluated.Image analysis by computerized software was applied to S-100 stained sections for assessment of neural hypertrophy.RESULTS:Difference between number of mast cells in HD group(mean=36.44)and in non-HD group(mean =14.79)was statistically significant.Image analysis morphometry on S-100 stained sections served as a useful adjunct.The difference between number,size,and perimeter of the nerve fibers between HD and non-HD group was statistically significant.CONCLUSION:Mast cells are significantly increased in HD and their base line values are much higher in Indian children than that reported in Western literature.Their role in HD needs further research.Morphometry of S-100 stained nerve fibers is a useful adjunct to conventional methods for diagnosis of HD.

Effect of fexofenadine, a mast cell blocker, in infertile men with significantly increased testicular mast cells

Aim: To investigate the role of fexofenadine, a mast cell blocker, on semen quality in the treatment of infertile men. Methods: The study included 16 Turkish idiopathic infertile men with azoospermia or oligozoospermia who underwent testicular biopsy to examine mast cells containing tryptase. In all patients, a complete medical history, clinical examination, semen analysis and serum hormone assay were carried out. The biopsy specimens were immunohistochemically stained with antihuman tryptase for mast cells. The number of total mast cells per seminiferous tubule was calculated and recorded as mast cell index. The patients were divided into two groups according to their mast cell index: the higher (≥1, n=9) and the lower (<1, n=7) index groups. Fexofenadine was administered orally at a dose of 180 mg/day for 4 to 9 months. Pre-and post-treatment semen parameters, including total motile sperm counts (TMC) were recorded and compared. Spontaneous pregnancies after the treatment were registered. Results: There was no statistically significant difference in TMC between the pre-treatment and post-treatment values in patients with higher and lower mast cell index (P≥0.05). In both groups, nobody had a significant response to the treatment and there was no spontaneous pregnancy after the treatment. Conclusion: Although testicular dysfunction is closely associated with increased number of testicular mast cells, fexofenadine, a mast cell blocker, appears not having any benefit in the treatment of Turkish infertile men with a significant increase in testicular mast cells. (Asian J Androl 2002 Dec; 4: 291-294)

Study on the Role of Mast Cells in the Development of Liver Fibrosis During Diethylnitrosamine (DEN) -induced Hepatocarcinogenesis in Rats

The mast cells(MC)and their roles in the development of liver fibrosis during experimental hepatocarcinogenesis in rats have been studied immunohistochemically and electron microscopically.Pronounced MC hyperplasia occurred after beginning of the treatment of DEN. The vast majority of mast cells in fibrotic livers was present in thickened fibrous septa.Intracellular or pericytial collagen tape IV and laminin staining were found in mast cells,collagen types I,III and fibronectin were negative.Mast cells mainly distributed in proximity to basement membrane and the electron microscopical observation revealed a close topographic relationship between mast cells and fibroblasts. The fibroblasts phagocytized the granules released by mast cells and thus were activated, showing enhanced formation of collagenous fibrils.The mast cells may be derived from blood circulation or replicated in situ. Those findings indicated that mast cells take part in the process of fibrosis at least by two ways:(1)It directly synthesizes the basement membrane components;(2)It stimulates the fibroblasts or other types of cells which have the potential functions in fibrogenesis by releasing granule mediators or cytokines acting upon the fibrosis process.

Mast cells and human hepatocellular carcinoma

AIM: To investigate the density of mast cells (MCs) in human hepatocellular carcinoma (HCC), and to determine whether the MCs density has any correlations with histopathological grading, staging or some baseline patient characteristics.METHODS: Tissue sections of 22 primary HCCs were histochemically stained with toluidine blue, in order to be able to quantify the MCs in and around the neoplasm using a computer-assisted image analysis system. HCC was staged and graded by two independent pathologists. To identify the sinusoidal capillarisation of each specimen 3μm thick sections were histochemically stained with sirius red, and semi-quantitatively evaluated by two independent observers. The data were statistically analysed using Spearman′s correlation and Student′s t-test when appropriate.RESULTS: MCs density did not correlate with the age or sex of the patients, the serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels, or the stage or grade of the HCC. No significant differences were found between the MCs density of the patients with and without hepatitis C virus infection, but they were significantly higher in the specimens showing marked sinusoidal capillarisation.CONCLUSION: The lack of any significant correlation between MCs density and the stage or grade of the neoplastic lesions suggests that there is no causal relationship between MCs recruitment and HCC. However, as capillarisation proceeds concurrently with arterial blood supply during hepatocarcinogenesis, MCs may be considered of primary importance in the transition from sinusoidal to capillary-type endothelial cells and the HCC growth.

Mast cells and multiple sclerosis in females and males

Mast cells were observed in autopsies from 11 females and 8 males. We confirm earlier observations that mast cells are more frequent in close vicinity to MS-plaques. In these plaque-border zone areas, defined as the area within 1 mm distance of the actual plaques, the average number of mast cells was 2.34/mm2 in males and 4.77/mm2 in females, which in average is appr. 10 times more than earlier observed in MS. The difference in number of mast cells between females and males is significant (p < 0.005) and is of interest since females are more inclined to developing MS than males. Mast cells were rare in areas without visible plaques. The mast cells were preferably located close to capillaries and venules. A mechanism for the probable role of mast cells, based on diet-factors and mast cell mediators in the pathogenesis of MS is discussed.

Neuroimmune connections between corticotropinreleasing hormone and mast cells:novel strategies for the treatment of neurodegenerative diseases

Corticotropin-releasing hormone is a critical component of the hypothalamic–pituitary–adrenal axis,which plays a major role in the body’s immune response to stress.Mast cells are both sensors and effectors in the interaction between the nervous and immune systems.As first responders to stress,mast cells can initiate,amplify and prolong neuroimmune responses upon activation.Corticotropin-releasing hormone plays a pivotal role in triggering stress responses and related diseases by acting on its receptors in mast cells.Corticotropin-releasing hormone can stimulate mast cell activation,influence the activation of immune cells by peripheral nerves and modulate neuroimmune interactions.The latest evidence shows that the release of corticotropin-releasing hormone induces the degranulation of mast cells under stress conditions,leading to disruption of the bloodbrain barrier,which plays an important role in neurological diseases,such as Alzheimer’s disease,Parkinson’s disease,multiple sclerosis,autism spectrum disorder and amyotrophic lateral sclerosis.Recent studies suggest that stress increases intestinal permeability and disrupts the blood-brain barrier through corticotropin-releasing hormone-mediated activation of mast cells,providing new insight into the complex interplay between the brain and gastrointestinal tract.The neuroimmune target of mast cells is the site at which the corticotropin-releasing hormone directly participates in the inflammatory responses of nerve terminals.In this review,we focus on the neuroimmune connections between corticotropin-releasing hormone and mast cells,with the aim of providing novel potential therapeutic targets for inflammatory,autoimmune and nervous system diseases.

Chronic Stress Induced Proliferation and Activation of Mast Cells of Gastric Antrum in Rats

To explore chronic eration and activation of mast heterotypic stressors induced prolifcells in gastric antrum mucosa by ultrastructure alterations of mast cells, chronic unpredictable heterotypic stressors were used as a study model. The mean immunofluorescence magnitude of mast cell protease 1 （MCP-1） taken from chronic stress rats were 37.4±7.7, significantly higher （p〈0.05） than the value of normal control group （24.8±5.6）. Chronic unpredictable haterotypic stressors appeared also to induce ultrastructure alterations of mast cells. It indicated that mast cells were proliferated and activated, while mast cell granules were hyperplasiaed. Most granules had obvious intragranular changes with loss of electron-dense material. The morphologic evidence showed that macrophages and leukocytes infiltrated in chronic stress rats. Some granules of leukocytes adhered to the surface of mast cell, and formed a bridge. Macrophages phagocytized the mast cell granules.

Mechanisms for amplified mediator release from colonic mast cells:Implications for intestinal inflammatory diseases

The mast cell is an enigmatic cell type whose physiological function has preoccupied large numbers of investigators for decadest. Some have concluded that the absence of mast cells is incompatible with life, at least in humans, because no human conditions have been documented where these cells are absent from the body. On the other hand, mice harboring specific mutations in certain growth factors, or their receptors, that

Activation of MRGPRB2 receptor in mouse peritoneal mast cells depends on PLC-IP3-ORAI1 pathway

OBJECTIVE A novel mast cell-specific G-protein-coupled receptor(GPCR),known as mas-related GPCR-B2(MRGPRB2),plays important roles in the immune response.The opening of ion channels mediated by MRGPRB2 activation remains unclear.METHODS AND RE⁃SULTS Calcium influx induced by activation of MRGPRB2 receptor in mouse peritoneal mast cells was related to the concentrations of calcium ions in the extracellular solution.Similarly,the volt⁃age-dependent current generated by MRGPRB2 activation was also correlated with the extracellu⁃lar calcium concentration.In addition,the in⁃creased of calcium influx or voltage-dependent current caused by activation of MrgprB2 could be blocked by U73122(PLC blocker)or 2-APB(IP3-ORAI1 blocker).Meanwhile,calcium-activated chlorine channel(TMEM16A)was involved in the generation of voltage-dependent currents in⁃duced by MRGPRB2 activation in mouse perito⁃neal mast cells.Furthermore,the degranulation of mouse peritoneal mast cells mediated by MRGPRB2 receptor could also be inhibited by U73122 or 2-APB.CONCLUSION PLC-IP3-ORAI1-TMEM16A signaling pathway was involved in MRGPRB2-mediated mast cell activation.

Effects of Different Toluidine Blue Dyes on Presenting Chicken Intestine Mast Cells

Chicken intestinal tissues were fixed with 4% paraformaldehyde and stained with the dyes of 1% toluidine blue, 0.5 % toluidine blue-ethanol and toluidine blue-potassium permanganate respectively. Chicken intestinal tissues stained by 1% toluidine blue showed that mast cells presented the lavender, while the staining was light and the structure was susceptible to be intervened, and it was difficult to observe the structures of mast cells. Chicken intestinal tissues stained by toluidine blue-potassium permanganate showed that the tissue sections presented the navy blue, the structures of mast cells could not be observed clearly. Chicken intestinal tissues stained by 0.5% toluidine blue-ethanol showed that the mast cells presented the blue-violet and the outlines were clear; the cytoplasm was hy- perchromatic and the staining of nucleus was light; the structures of mast cells could be clearly distinguished from the surrounding structures. In conclusion, the staining effect of 0.5% toluidine blue-ethanol on chicken intestine mast cells was good and the structure of mast cell could be observed clearly.

Intracellular localisation of Mycobacterium marinum in mast cells

AIM： To study the bacteriocidal or bacteriostatic role of mast cells during infection with Mycobacterium.METHODS： Mycobacterium marinum （M. marinum） （BAA-535/M strain） was investigated for its ability to grow at a temperature relevant to the mammalian host. Primary mast cells were differentiated from bone marrows of mice, a human mast cell line （HMC-1） and a human monocytic cell line （MonoMac6） were maintained in culture. Mice were stimulated by intra-peritoneal injection of heat-killed M. marinum to study cytochemically the degranulation of peritoneal mast cells. HMC-1 cells were stimulated with M. marinum to analyse mRNA expression for inflammatory reactant genes, while HMC-1 and primary mouse mast cells were infected with M. marinum to establish in parallel cell viability （lactate dehydrogenase release and cell counts） and viable mycobacterial counts. Flow cytometry was used to assess intracellular presence of fluorescein isothiocyanate labelled M. marinum after trypan blue quenching and to measure the extent of infection-induced apoptosis or necrosis in HMC-1. A GFP expressing recombinant M. marinum strain was used to assess intracellular location by fuorescence microscopy. Light microscopy of osmium tetroxide and Gram Twortstained sections of 0.5 μm and transmission electron microscopy were undertaken as sensitive methods. RESULTS： Since its isolation, M. marinum has adapted to grow at 37 ℃. This study found that M. marinum infects HMC-1 cells and primary murine mast cells, where they survive, replicate, and cause dose dependent cell damage over the analysis period of up to 120 h. Amikacin was an effective aminoglycoside antibiotic to eliminate extracellular or membrane attached M. marinum in order to adequately quantify the intracellular bacterial loads. In vivo, intraperitoneal injection of heat-killed M. marinum led to the release of mast cell granules in mice. HMC-1 cells stimulated with M. marinum showed a biphasic pattern of increased mRNA expression for LL-37 and COX-2/TNF-a during 24 h of stimulation. In HMC-1, M. marinum localised to the cytoplasm whereas in primary mast cells, M. marinum were found in vacuoles.CONCLUSION： The effector role of mast cells in infection with M. marinum can be studied in vitro and in vivo.

Mast Cells:The Key to Multiple Sclerosis?

Mast cells are present in high numbers in the border-zones of the multiple sclerosis-plaques. They are located in small clusters along capillaries and venules, and they are more abundant in females than in men. Mast cells can be stimulated to release specific mediators such as histamine, resulting in oedema formation, as well as proteases that may cause demyelination, by several different activation mechanisms. We hypothesize that a putative mast cell activation may be induced by diet factor(s) as well as long lasting mental stress that may lead to the release of catestatin, as well as ACTH released from the pituitary gland. Given a natural flux of mast cell recovery and activation, a putative phenomenon of massive release of mediators and “silent” reload periods may explain the relapsing-remitting phases of multiple sclerosis.

Fine-tuning Mast Cells is Essential for the Maintenance and Regulation of the Systemic and Immune Homeostasis

During the past decades,populous expansion in mast cell scientific literature came forth with more,than forty-four thousand PubMed publications available to date.Such surge is due to the appreciation of the momentous role of mast cells in the evolution of species,in the development and maintenance of vital physiological functions,such as reproduction,homeostasis,and fluids,diverse immunological roles,and the potential of far-reaching effects despite minute numbers.While the emerging knowledge of the importance of mast cells in equilibrium comes of age when looking at the matter from an evolutionary perspective,the recognition of mast cells beyond detrimental performance in allergies and asthma,during protection against parasites,falters.Beyond wellknown classical functions,mast cells can process and present antigens,can serve as a viral reservoir,can respond to hormones and xenobiotics,initiate antiviral and antibacterial responses,phagocytosis,apoptosis,and participate in important developmental cornerstones.During evolution,upon the development of a sophisticated niche of innate and adaptive cell populations,certain mast cell functions became partially transmutable,yet the potency of mast cells remained considerable.Reviewing mast cells enables us to reflect on the certitude,that our sophisticated,complex physiology is rooted deeply in evolution,which we carry ancient remnants of,ones that may have decisive roles in our functioning.This communication sets out the goal of characterizing mast cells,particularly the aspects less in limelight yet of immense significance,without the aspiration exhaust it all.

30 and 32 kDa outer membrane proteins of Bordetella pertussis as a modulator on promoting degranulation of mast cells

The correlation between the activities of the outer menbrane proteins （OMPs） of Bordetella pertussis and the lgE-mediated asthma was investigated in the present study, in which the OMPs of B. pertussis and their components were prepared by detergent treatment and chromatography, and the molecular weights of the OMPs components were determined by SDS-PAGE. The amounts of total as well as the ovalbumin （OVA）-specific IgE induced by dead B. pertussis whole bacterial vaccine on guinea pigs were detected by ELISA. Meanwhile, the effect of the OMPs and their components to promote the degranulation of guinea pig mast cells was observed by using the mast cell degranulation test, and ELISA assay was used to measure the histatmine levels in the supematants from the mast cell cultures. Histamine sensitive test was used to demonstrate the effects of the OMPs and their components to increase the histamine lethal sensitivity in mice. It was found that four components with molecular weights of 30, 32, 38 and 69 kDa could be obtained from the OMPs of B. pertussts, and the dead whole bacteria vaccine of B. pertussis had the ability to increase the levels of the total as well as the OVA-specific IgE in sera of guinea pigs. The OMPs and their 30 and 32 kDa components demonstrated significantly enhancing effect on the degranulation of guinea pig mast cells, and the histamine levels in the supematants from the mast cell culture treated with OMPs and their 30 and 32 kDa components were also significantly increased. It is evident that the strong adjuvant activity and the enhancing effect to degranulation of mast cells and the release of histamine of certain outer membrane components of B. pertussis could be demonstrated as revealed by the results of the present study, suggesting the possibility of a close relationship between the infection of vaccination with B. pertussis and the IgE-mediated asthma.

Decreased expression of serotonin in the jejunum and increased numbers of mast cells in the terminal ileum in patients with irritable bowel syndrome

AIM: To investigate if there are changes in serotonin (5-HT) levels, enterochromaffin (EC) cells and mast cells in small intestinal mucosa of patients with irritable bowel syndrome (IBS). METHODS: Diarrhea-predominant (IBS-D, n = 20), or constipation-predominant (IBS-C, n = 18) IBS patients and healthy controls (n = 20) underwent colonoscopy and peroral small intestinal endoscopy, and mucosal samples were obtained at the descending part of the duodenum, proximal end of jejunum and terminal ileum. High-performance liquid chromatography- electrochemistry and immunohistochemical methods were used to detect 5-HT content, EC cells and mast cells. RESULTS: (1) There were no differences in the number and distribution of EC cells between IBS patients and the normal group. (2) The mucosal 5-HT contents at the duodenum, jejunum and ileum in IBS-C patients were 182 ± 90, 122 ± 54, 61 ± 35 ng/mg protein, respectively, which were all lower than those in the normal group (256 ± 84, 188 ± 91, and 93 ± 45 ng/ mg protein, respectively), with a significant difference at the jejunum (P < 0.05). There were no differences in the small intestinal mucosal 5-HT contents between IBS-D patients and the normal group. The mucosal 5-HT contents at the duodenum were significantly higher than those at the ileum in the three groups (P < 0.001). (3) The numbers of mast cells in patients with IBS-C and IBS-D at the ileum were 38.7 ± 9.4 and 35.8 ± 5.5/highpower field (hpf), respectively, which were significantly more than that in the normal group (29.8 ± 4.4/hpf) (P < 0.001). There was no significant difference in the numbers of mast cells at the other two parts between IBS patients and the normal group. The numbers of mast cells in IBS-C, IBS-D, and normal groups were all significantly higher at the ileum (38.7 ± 9.4, 35.8 ± 5.5, 29.8 ± 4.4/hpf, respectively) than at the duodenum (19.6 ± 4.7, 18.5 ± 6.3, 19.2 ± 3.3/hpf, respectively, P < 0.001). CONCLUSION: The changes in the 5-HT signaling pathway at the jejunum of IBS-C patients and the increase in mast cells in patients with IBS at the terminal ileum may offer evidence to explain the pathogenesis of IBS.