Characteristics Of Mast Cells Research Articles

Machine learning–based identification and characterization of mast cells in eosinophilic esophagitis

BackgroundEosinophilic esophagitis (EoE) is diagnosed and monitored using esophageal eosinophil levels; however, EoE also exhibits a marked, understudied esophageal mastocytosis. ObjectiveUsing machine learning, we localized and characterized esophageal mast cells to decipher their potential role in disease pathology. MethodsEsophageal biopsy samples (EoE, control) were stained for mast cells by anti-tryptase and imaged using immunofluorescence; high-resolution whole tissue images were digitally assembled. Machine learning software was trained to identify, enumerate, and characterize mast cells, designated Mast Cell-Artificial Intelligence (MC-AI). ResultsMC-AI enumerated cell counts with high accuracy. During active EoE, epithelial mast cells increased and lamina propria (LP) mast cells decreased. In controls and EoE remission patients, papillae had the highest mast cell density and negatively correlated with epithelial mast cell density. Mast cell density in the epithelium and papillae correlated with the degree of epithelial eosinophilic inflammation, basal zone hyperplasia, and LP fibrosis. MC-AI detected greater mast cell degranulation in the epithelium, papillae, and LP in EoE patients compared with control individuals. Mast cells were localized further from the basement membrane in active EoE than EoE remission and control individuals but were closer than eosinophils to the basement membrane in active EoE. ConclusionUsing MC-AI, we identified a distinct population of homeostatic esophageal papillae mast cells; during active EoE, this population decreases, undergoes degranulation, negatively correlates with epithelial mast cell levels, and significantly correlates with distinct histologic features. Overall, MC-AI provides a means to understand the potential involvement of mast cells in EoE and other disorders.

Characterization of Mast Cells from Healthy and Varicose Human Saphenous Vein.

Mast cells (MCs) are distributed in tissues throughout the body and are highly involved in many physiological and pathophysiological processes. The potential and involvement of different MC phenotypes are still not well understood. MCs are present in blood vessel walls, but their specific phenotypic features are unknown. We aimed at characterizing MCs from human saphenous veins for localization, mediator content, and receptor expression. This was done in MCs from both healthy and varicose human saphenous veins (hSV and vSV, respectively). For both vSV and hSV, we found that vein MCs are mainly present in the tunica adventitia (99% MCs in adventitia) and that the population consists of both MCT and MCTC phenotypes (vSV: 55% MCT, hSV: 64% MCT). The vein MCs contained high levels of histamine (vSV: 27 pg/MC, hSV: 55 pg/MC) and tryptase (vSV: 98 pg/MC, hSV: 111 pg/MC), indicating a strong potential for regulatory effects on blood vessels. The receptor expression of FcεRI, MRGPRX2, PTAFR, C3aR, and C5aR was found, even though the percentage of positive cells differed between vSV and hSV MCs. We conclude that vein MCs from the blood vessel wall have a high potential to affect the tissue around them.

Discussion of the immunomorphological role of interactions between mast cells and Helicobacter pylori in the gastric mucosa

Helicobacter pylori induced gastritis accounts for 70% of cases in the structure of this pathology. Features of the long-term inflammatory reaction of the mucous membrane are directly related to the mechanisms of bacterial pathogenicity, and features of immunogenesis within narrow limits of the specific tissue microenvironment of organ structures. Mast cells appear to be one of the key players (promoters) in the regulation of the inflammatory mediator cascade and the formation of cytokine-induced expression. Possessing a wide arsenal of biologically active substances, mast cells are able to participate in the formation of the immune response and resistance of the gastric mucosa, modulating both pro- and anti-inflammatory effects. The antigen-presenting features of mast cells are of interest in terms of interaction with H. pylori and induction of mucosa bacterial colonization. The aim of study was to assess the mast cell tryptase profile of the gastric mucosa in the immunopathogenesis of H. pylori-associated inflammation. Material and methods. The study included 19 biopsies of the gastric mucosa with unknown status of H. pylori infection. Microslides were stained with hematoxylin and eosin, and Giemsa's dye for plain microscopy. H. pylori infection of the gastric mucosa was detected using the immunohistochemical method. Using double immunofluorescent labeling, localization of tryptase-positive mast cells and H. pylori strains was detected. Results. In patients infected with H. pylori (n=12), there was a significant increase in the number of tryptase-positive mast cells (177.99±30.55 vs 88.58±11.49; p<0.05) with activation of secretory pathways and release of protease into the extracellular matrix of the gastric mucosa. The quantitative parameters of mast cells in the group of patients with an undetected pathogen and signs of a chronic inflammation of the gastric mucosa were statistically significantly lower than in the group of infected patients. Co-localization of tryptase-positive mast cells and H. pylori strains (with the formation of areas of large free-lying granule accumulation around the glands with pronounced degree of H. pylori contamination) was detected in gastrobiopsy specimens, the fact evidencing their close involvement in the development of inflammatory reactions of the gastric mucosa. Conclusion. The study demonstrated the features of mast cells and H. pylori interaction revealing previously unknown aspects of gastritis pathophysiology. The data obtained contribute a valuable insight to choose a treatment strategy for H. pylori-associated gastritis.

Detection and Isolation of Airway Mast Cell Subsets in Mouse and Human.

Mast cells are heterogeneous, tissue-resident immune effector cells widely recognized to play pathobiologic roles in the development of mucosal type 2 inflammation. While mast cell progenitors can be found in peripheral blood, phenotypically mature mast cells can only be found within peripheral tissues. Here, we describe optimized tissue digestion protocols for obtaining mast cells from the murine lung and from human sinus tissue. Following tissue digestion, mast cells can be identified and sorted by flow cytometry using antibodies against defined surface markers. We also provide protocol for intracellular protease immunostaining, allowing for further characterization of mast cells.

Mast cells participate in chronic low-grade inflammation within adipose tissue.

Obesity is reckoned as one of the civilization diseases, posing a considerable global health issue. Evidence points towards a contribution of multitude immune cell populations in obesity pathomechanism and the development of chronic low-grade inflammation in the expanded adipose tissue. Notably, adipose tissue is a reservoir of mast cells which number in individuals with obesity particularly increased. Some of them tend to degranulation what generate secretion of strong pro-inflammatory and regulatory mediators, as well as cytokines/chemokines. Several lines of evidence suggest that mast cells are strictly associated with pro-inflammatory status in adipose tissue by their indirect impact on immune cell attraction and activation. Furthermore, mast cells affect adipose tissue remodelling and fibrosis by adipocyte differentiation, fibroblast proliferation and enhancing extracellular matrix proteins expression. This review will summarize current knowledge on mast cell features and their role in the development of chronic low-grade inflammation within adipose tissue.

Characterization of mast cells in the wall of the cerebral arterial systems in the rat and the baboon

Rat brain perivascular mast cells have been characterized histochemically and ultrastructurally in other studies (Dimitriadou, 1990). In our earlier studies in the vervet monkey circulus arteriosus, cells resembling mast cells were seen within the tunica adventitia. In our current studies on whole mount preparations of arterial vessels, branching from the circulus arteriosus in both the rat and the baboon, labeling experiments with mast cell tryptase and confocal immunofluorescent microscopy show that mast cells do exist in the wall of the vessels in the two animal species. Fluorescent immunohistochemistry studies of the arterial vessels using serotonin antibody have shown that the mast cells contain serotonin in their granules. Colocalization of mast cell tryptase and serotonin confirmed that these are in the same cell. Colocalization of mast cell tryptase and tryptophan hydroxylase confirmed that serotonin synthesis occurred in the same cell. Other studies will attempt to determine the density of the mast cells in the wall of the vessels.Grant Funding Source: Department of Anatomy and Cell Biology OSU Center for Health Sciences

Characterization of mast cells according to their content of tryptase and chymase in normal and neoplastic human uterine cervix

Abstract.Cabanillas-Saez A, Schalper JA, Nicovani SM, Rudolph MI. Characterization of mast cells according to their content of tryptase and chymase in normal and neoplastic human uterine cervix.Mast cells (MC) have been associated with diverse human cancers. The primary function of these cells is to store and release a number of biologically active mediators, including the serine proteases tryptase and chymase. These proteases have been closely related with angiogenesis and tumor invasion, two critical steps during tumor progression. In the present work we analyzed the presence of MC in human uterine cervix from both normal and neoplastic tissues by using metachromatic, immunohistochemical, and enzymohistochemical staining. Tryptase-positive (MCT)– and tryptase/chymase-positive (MCTC)–mast cells were found in both normal and neoplastic tissues. The phenotype predominantly expressed in normal tissues as well as in benign and malignant lesions of the uterine cervix was the MCT. The total number of MC remained constant through the different stages of malignant transformation (cervical intraepithelial neoplasia grade 1–3) but a significant increase in the invasive carcinoma (IC) group was observed, this increase being mainly due to the MCTphenotype. Furthermore, we detected abundant MCTbut not MCTCinfiltrating tumors in sections of IC. Regarding the potent angiogenic properties described for tryptase, these findings suggest that in advanced stages of malignancy the significant number of MCTdistributed within the cervical tissues could provide an effective mechanism to create the abundantly vascularized microenvironment required for tumor cells to proliferate and disseminate.

Cells with Features of Mast Cells and Basophils

Cells with Features of Mast Cells and Basophils

Mast cells and basophils in acquired immunity.

In this review we describe the basic biology of mast cells and basophils and discuss their proposed effector and immunoregulatory roles in acquired immunity, particularly the IgE-associated immune responses. While mast cells and basophils share a number of similarities, they also differ in many aspects of natural history and function. Both mast cells and basophils express the high affinity receptor for immunoglobulin E (Fc epsilon RI) on their surface and can be activated to secrete diverse preformed, lipid and cytokine mediators after crosslinking of Fc epsilon RI-bound IgE with bi- or multivalent antigen. Thus, both cell types can represent important effector cells, as well as potential immunoregulatory cells, in IgE-mediated acquired immunity. However, mature mast cells are long-term residents of vascularized tissues, whereas basophils are granulocytic leukocytes that circulate in mature form and must be recruited into tissues that are sites of inflammatory or immune responses. The similarities and differences in the natural history, mediator content and other features of mast cells and basophils not only strongly indicate that these cells represent distinct hematopoietic lineages that can express complementary or overlapping functions, but also offer insights into the specific roles of these cells in acute, 'late phase' and chronic aspects of adaptive or pathological IgE-associated acquired immune responses.

270 Interleukin-10 modulates mast cell features

270 Interleukin-10 modulates mast cell features

Effects of Mutant c-Kit in Early Myeloid Cells

Activating mutations in c-Kit, the receptor for Stem Cell Factor (SCF), have been identified in dysplasias and leukaemias of the mast cell lineage and have been shown to contribute to transformation in model systems. Early myeloid cells also normally express c-Kit and their survival, proliferation and differentiation is promoted by SCF. It might therefore be expected that c-Kit mutations could also be involved in some acute and/or chronic myeloid leukaemias. We have found that mutant c-Kit (and normal c-Kit in the presence of SCF) provides a strong differentiation stimulus in normal and immortalised murine early myeloid cells. Since maturation of haemopoietic cells, with the exception of mast cells, results in down-regulation of c-Kit expression, the transforming effects of mutant receptor may be self-limiting in most lineages. This is consistent with the observation that multipotential progenitor cells from some patients with systemic mastocytosis express mutant c-Kit. However, c-Kit mutations have been observed in a few cases of myelodysplastic syndromes or AML without mast cell features. Oncogenesis involves multiple genetic changes and the phenotype of malignant haemopoietic cells expressing mutant c-Kit may be influenced by co-oncogenic events. For example mutations blocking the differentiative effect of mutant c-Kit might result in AML rather than mastocytosis. Thus the extent to which c-Kit mutations contribute to malignancies of early myeloid phenotype remains unknown, and resolution of this issue is complicated by the heterogeneity of this family of diseases.

Cultured human basophils with ultrastructural and ultracytochemical features of mast cells

To clarify whether in vitro-cultured basophils have features of mast cells, basophils grown in semisolid and liquid culture were studied ultrastructurally and cytochemically and were compared with freshly isolated basophils and mast cells. Ultrastructurally, the cultured basophils had pleomorphic cytoplasmic granules, some of which were similar to mast cell granules. However, scroll formation, characteristic of mast cell granules, was not observed in cells grown in semisolid and liquid culture. Cytochemically, the reactivity patterns of acidic glycoconjugates in the cultured cells more closely resembled those of the freshly isolated basophils than of the mast cells. In addition, the basophils grown in liquid culture showed a more matured form and had stronger reactivity to glycoconjugates, acid phosphatase and peroxidase than did the cells grown in semisolid culture, suggesting that the liquid culture system was better for the basophil.

Investigation of Mast Cell Differentiation in vivo by Use of Monoclonal Antibodies

In the present study mast cell differentiation/maturation was studied in vivo after depletion of mature mast cells from the peritoneal cavity by injection of distilled water. The reconstituting cell population was characterized by use of different staining methods. Additionally, the monoclonal antibody (MAb) IWF F2, which recognizes a membrane antigen of rat mast cells, was used to follow up mast cell differentiation/maturation in the course of the experiment. The antigen expression was studied both by immunofluorescence of antigen-bearing cells and by MAb inhibition of compound 48/80-stimulated histamine release from mast cells. In the course of the experiment the amount of antigen-positive cells increased continuously from less than 5% to control level (1st and 22nd days, respectively). The expression of the membrane antigen detectable by the MAb precedes the appearance of cytochemically identifiable mast cells for several days. The mast cells mature morphologically and functionally as indicated by increasing size, histamine content and MAb inhibition of compound 48/80-stimulated histamine release. The results obtained suggest the MAb IWF F2 to be a useful methodical tool for additional characterization of mast cell differentiation/maturation processes.

Fibroblast-dependent growth of mouse mast cells in vitro: duplication of mast cell depletion in mutant mice of W/Wv genotype.

In spite of the apparent depletion of mast cells in tissues of mutant mice of W/Wv genotype, cells with many features of mast cells do develop when bone marrow cells of W/Wv mice are cultured in the presence of pokeweed mitogen-stimulated spleen cell-conditioned medium (PWM-SCM). In order to resolve this discrepancy and facilitate the analysis of the W mutation, we attempted to establish an in vitro system in which the in vivo defect of W/Wv mice can be reproduced. Cultured mast cells (CMC) were developed from bone marrow cells of either W/Wv or congenic +/+ mice, and then co-cultured with NIH/3T3 mouse fibroblasts in media supplemented only with fetal calf serum (i.e., in the absence of PWM-SCM). Under this condition, CMC from +/+ mice continued to divide and were maintained for more than 4 weeks. The supportive effect of NIH/3T3 cells required close-range interactions with CMC and was not due to synthesis of the known mast cell growth factors, interleukins 3 and 4. By contrast, CMC from W/Wv mice were not maintained, and the number of mast cells remaining after 4 weeks of co-culture was only 1% of the normal +/+ counterparts. Thus, the humoral factor-independent and cell contact-dependent system presented here revealed the intrinsic defects in growth and differentiation of CMC derived from W/Wv mice and might be useful for biochemical and molecular analysis of the gene product(s) encoded at the W locus.

Composition and ultrastructure of elasmobranch granulocytes. III. Sharks (Lamniformes)

The peripheral blood granulocyte composition of five species of shark is given together with ultrastructural observations made on the epigonal organ and blood of Mustelus lenticulatus and spleen of Apristurus sp. Three granulocyte lineages occurred in Mustelus. Ultrastructurally, eosinophilic granulocytes contained granules that were very variable in size and contained parallel fibrillar arrays that were unidirectional in small granules, but which were often orientated in several directions in larger granules. This dense core material sometimes formed angular crystalloids.Eosinophils had ovoid or irregular granules that were usually uniformly electron‐dense, but some had an eccentric ovoid area of greater electron‐density. Some eosinophils enter the blood where they are phagocytic, but others, in blood and epigonal organ, showed an unusual but characteristic process of disintegration, leaving a ragged cell full of cellular debris.The third granulocyte type had features of mast cells and basophils of higher vertebrates and was tentatively identified as belonging to that lineage. The inter‐relationships of these cells, and of them with granulocytes of other elasmobranchs, are discussed.

In Vitro Induction and Characterization of Mast Cells from Murine Peyer's Patches

The present study was carried out in vitro to determine whether murine Peyer's patches (PP) can be a source of mucosal mast cells, using a well-defined mast cell growth factor, interleukin 3 (IL-3). The non-T, non-B, non-adherent (null) cell population of PP contained the precursor cells for mast cells. The mast cells induced possessed toluidine blue and alcian blue (pH 3)-positive granules, which were heterogeneous and contained histamine. The IL-3-induced mast cells were IL-3-dependent, did not express Ia, T-cell, B-cell or macrophage markers, and released histamine in response to Ca ionophore, but not in response to compound 48/80. These cells bore IgE-specific surface receptors and intracellular 20 alpha hydroxysteroid dehydrogenase. The latter enzyme activity was induced by IL-3 in null cells. All these features of the mast cells support the view that these cells belong to a lineage of mucosal mast cells (MMC) and are no different from those of other lymphoid tissues, such as the bone marrow and spleen. In the analysis of MMC precursor frequency, PP had a similar frequency to that of other gut-associated lymphoid tissues (mesenteric lymph nodes and lamina propria), but was much lower when compared to those of the bone marrow and spleen. Furthermore, like IL-2, PP are capable of producing IL-3 in vitro by activating their helper marker-bearing T cells. Thus, under certain conditions, such as the initial participation by PP in MMC-associated intestinal immune responses, PP are likely to provide MMC in their microenvironment, like mucosal T and B cells.

An ultrastructural study of mast cells in the alveolar wall of normal and asthmatic lung.

Specimens of normal and asthmatic lungs were studied at the electron microscopic level and the frequency and ultrastructural features of mast cells and their granules within the alveolar wall were assessed with morphometric techniques. The numerical density of mast cells per square millimetre of alveolar wall was 299 (SD = 258) in normal and 366 (SD = 260) in asthmatic lung. The mean area of the mast cell nucleated profile was 25.7 microns2 (SD = 6.3) in normal lung and 29.8 (SD = 6.2) in asthmatic. The average number of secretory granules per single mast cell nucleated profile was 55 (SD = 13) in normal lung and 60 (SD = 12) in asthmatic lung. The diameter of the individual secretory granule was 338.9 nm (SD = 42.6) in normal and 345.6 (SD = 47.7) in asthmatic lung. The volume density of secretory granules in normal and asthmatic lung was 6.31 microns3 and 5.81 microns3, respectively. The mean diameter of the individual subunit ('scroll') inside the secretory granule was 88.8 nm for both normal and asthmatic lung. In normal lung 64.2% of granules were of 'scroll' and 'combined' type, and 35.8% of granules were 'particulate' or 'empty'. In specimens from asthmatic patients 40.3% of granules had 'scroll' or 'combined' structures and 59.7% were 'particulate' or 'empty'. Our data suggest that there is no difference between the number of mast cells in normal and asthmatic lung. However, in pulmonary mast cells from asthmatic lung, degranulation is more common than in normal lung.

Morphological and physiological features of mast cells of subcutaneous connective tissue in rats with arterial hypertension

Morphological and physiological features of mast cells of subcutaneous connective tissue in rats with arterial hypertension

Mast Cells in Behçet’s Disease: Ultrastructural and Histamine Content Studies

In order to assess the role of mast cells in the pathogenesis of mucocutaneous lesions of Behçet's disease, the following investigations were performed: (1) a comparative study of ultrastructural features of mast cells in spontaneous and reactive (pathergic) lesions of the process and in apparently uninvolved skin of patients in the active stage of the disease; (2) comparative estimation of the histamine content at the site of cutaneous hyperreactivity lesions and in apparently uninvolved skin of the same patients. Various forms and degrees of degranulation were revealed among the mast cells. These forms were obviously more frequent in spontaneous and reactive lesions than in the uninvolved skin, 66 and 56% as compared with 7.7%. Also the histamine content was twofold more in the reactive lesions than in the unaffected skin of the same patient, 43 ng/mg tissue as compared with 21 ng/mg tissue. The results of our study seem suggestive of an active role of mast cells in this process. The role is probably similar to that of basophils in cutaneous basophilic hypersensitivity.

A fine structure study of some cellular components in allergic reactions

SummarySkin samples from patients with Urticaria pigmentosa, Urticaria both spontaneous and induced, and from normal individuals has been examined and mast cell ullrastructure described. The features of mast cells in skin are compared with those in nasal and bronchiolar tissue and distinguishing features areas follows. (1) Skin mast cells tend to have longer villous extensions of plasma membrane. (2) Granules in skin mast cells have very frequent crystalline inclusions; these are uncommon in other tissues examined so far.Degranulation of the mast cells was observed and appears similar to that seen in other tissues.