Chymase-positive Mast Cells Research Articles

On the pathogenesis of COVID-19: the role of transforming growth factor beta

Proteins of the transforming growth factor beta (TGF-β) family regulate numerous cellular processes that are essential in the pathogenesis of acute respiratory distress syndrome (ARDS), contributing to increased alveolar epithelial permeability, activation of fibroblasts, and extracellular matrix remodeling. TGF-β is involved in the pathogenesis of inflammatory respiratory diseases during the development of COVID-19. SARS-CoV-2 leads to complex immune responses that include the release of inflammatory cytokines, increased activity of mast cells, and the release of mast cell secretome, in particular profibrotic enzymes and cytokines, including TGF-β.Tryptaseand chymase-positive mast cells play a major role in pulmonary fibrosis and embolism in COVID-19. Mast cell chymase is angiotensin-converting enzyme 2-independent due to extracellular formation of angiotensin II in the interstitium; it also activates TGF-β and other molecules, thereby playing a role in tissue remodeling. Mast cell β-tryptase increases the secretion of TGF-β1 by airway smooth muscle tissue and the expression of α-smooth muscle actin (α-SMA). TGF-β also induces the generation of mitochondrial reactive oxygen species (ROS), which enhances the production of ROS in lung fibroblasts. TGF-β is crucial for induing the synthesis of extracellular matrix components by fibroblasts.The review is devoted to the structure of TGF-β, the sources of its secretion and functions, the mechanism of its involvement in the pathogenesis of COVID-19, and the possibility of its use as a prognostic marker of COVID-19 severity.

On the Role of Mast Cells and Their Proteases in the Severe COVID-19

During the pandemic of the new coronavirus infection COVID-19 the question about the importance of mast cells and their proteases arose. The aim of this study is to determine the role of mast cells and their proteases chymase and tryptase in the pathogenesis of severe COVID-19. Materials and methods. The study included 55 patients: 29 male (52,7 %) and 26 female (47,3 %) aged 67 [62;71] years with severe COVID-19 and fatal outcome. An analysis of postmortem lung biopsies of patients with COVID-19 was carried out, determining the representation of mast cells, protease profile and degranulation activity. A correlation analysis was carried out between mast cell and clinical and laboratory parameters of patients. Results. Increased number of mast cells and their degranulation activity were found in patients with chronic heart failure, obesity, chronic kidney disease, coronary heart disease and acute cerebrovascular accident. Degranulation of tryptase-positive mast cells are depleted as the duration of the disease increases: the content of single tryptase-positive mast cells (%) negatively correlates with the duration of the disease and hospitalization (p = 0,015, r = -0,327 and p = 0,006, r = -0,368, respectively), the content of tryptase-positive mast cells fragments (%)correlates with the duration of hospitalization (p = 0,007, r = 0,357). Correlations were established between the levels of non-conjugated bilirubin and alanine aminotransferase with the content of single tryptase-positive mast cells (per mm2) (r = 0,340, p < 0,05 and r = 0,307, p < 0,05, respectively), as well as single degranulated tryptase-positive mast cells (per mm2) (r = 0,369, p < 0,05 and r = 0,363, p < 0,01, respectively), and the level of conjugated bilirubin with the content of single tryptase-positive mast cells (%) (r = 0,415, p < 0,05). The blood calcium level correlates with the absolute total content of single tryptase-positive mast cells (p = 0,013, r = 0,457), as well as degranulated (p = 0,017, r = 0,441). A negative correlation was also found between potassium level and the relative content of single non-degranulated tryptase-positive mast cells (p = 0,014, r = -0,352). Correlations were found between the level of total bilirubin at the time of admission and over time with the content of single degranulated chymase-positive mast cells (per mm2) (p = 0,043, r = 0,277 and p = 0,027, r = 0,317, respectively). Urea level upon admission positively correlates with the absolute total content of single chymase-positive mast cells (p = 0,045, r = 0,277), as well as degranulated (p = 0,04, r = 0,283). The potassium level in the blood correlates with the total content of co-adjacent chymase-positive mast cells (p < 0,05, r = 0,388), as well as content of co-adjacent degranulated chymase-positive mast cells (p < 0,05, r = 0,388). Conclusion. Significant correlations were noted between mast cells parameters and duration of the disease and hospitalization, the presence of comorbidities, unconjugated and conjugated bilirubin, ALT, urea, total protein, sodium, potassium and calcium blood levels. An increase in the number of mast cells and their degranulation activity has been found in patients with comorbidities: chronic heart failure, obesity, chronic kidney disease, ischemic heart disease and previous stroke. The revealed depletion of degranulation processes of tryptase-positive mast cells as the duration of the disease increases indicates their role in lung damage. We noted participation of mast cells and their proteases chymase and tryptase in the development of liver and kidney damage in patients with COVID-19, which confirms their importance in the severe course of the disease and may be considered in the future for the development of pathogenetic therapy.

Histochemical and immunohistochemical investigation of the number and localization of mast cells in the feline tongue.

This is the first study to describe the subtypes, number and distribution of mast cells (MC) in cat tongue by histochemical and immunohistochemical methods. Six male adult felines' tongue tissue samples consist of the study's material. Samples were fixed in 10% formaldehyde. MC number and distribution in the feline tongue were assessed using toluidine blue. Also, sections taken from blocks were stained in alcian blue/safranin O (AB/SO) combined dyes to determine the MC subtypes. The Streptavidin biotin complex method using anti-chymase and anti-tryptase primary antibodies was used for immunohistochemistry. Metachromatic MCs were mainly observed in the lamina propria close to the multilayered keratinized stratified squamous epithelium. The high number of MCs in this region may be because the dorsal surface of the tongue plays an essential role in the defence system of tongue tissue and, thus, of the body as a whole. Additionally, the number of MCs stained with AB (+) (1.7 ± 0.08) in the feline tongue was statistically higher than those with SO (+) (0.18 ± 0.02). This might be interpreted as an indication that MC heterogeneity may be due not only to their staining properties but also to their localization. It is also conceivable that the high histamine content may be a factor in this. Tryptase-positive MCs were found in the loose connective tissue around blood vessels, between the glands, as solitary cells, or in groups of several cells. Chymase-positive MCs were observed more individually rather than in groups. Moreover, chymase-positive MCs were detected to be located in the filiform papillae subepithelial and in the blood vessels' immediate vicinity. Animals often lick themselves to clean themselves and promote healing. For this reason, it is very important to protect the tongue, which is in direct contact with the external environment, against foreign agents. Considering both the functional and protective properties of the tongue, we concluded that MCs may play a role in oral cavity immunity and protective effect.

Involvement of Mast Cells in the Pathology of COVID-19: Clinical and Laboratory Parallels.

Recent studies suggested the potential role of mast cells (MCs) in the pathology of coronavirus disease 2019 (COVID-19). However, the precise description of the MCs' activation and the engagement of their proteases is still missing. The objective of this study was to further reveal the importance of MCs and their proteases (chymase, tryptase, and carboxypeptidase A3 (CPA3)) in the development of lung damage in patients with COVID-19. This study included 55 patients who died from COVID-19 and 30 controls who died from external causes. A histological analysis of the lung parenchyma was carried out to assess the protease profiles and degranulation activity of MCs. In addition, we have analyzed the general blood test, coagulogram, and C-reactive protein. The content of tryptase-positive MCs (Try-MCs) in the lungs of patients with COVID-19 was higher than in controls, but their degranulation activity was lower. The indicators of chymase-positive MCs (Chy-MCs) were significantly lower than in the controls, while the content of CPA3-positive MCs (CPA3-MCs) and their degranulation activity were higher in patients with COVID-19. In addition, we have demonstrated the existence of correlations (positive/negative) between the content of Try-MCs, Chy-MCs, and CPA3-MCs at different states of their degranulation and presence (co-adjacent/single) and the levels of various immune cells (neutrophils, eosinophils, basophils, and monocytes) and other important markers (blood hemoglobin, activated partial thromboplastin time (aPTT), international normalized ratio (INR), and fibrinogen). Thus, the identified patterns suggest the numerous and diverse mechanisms of the participation of MCs and their proteases in the pathogenesis of COVID-19, and their impact on the inflammatory process and coagulation status. At the same time, the issue requires further study in larger cohorts of patients, which will open up the possibility of using drugs acting on this link of pathogenesis to treat lung damage in patients with COVID-19.

Space-Flight- and Microgravity-Dependent Alteration of Mast Cell Population and Protease Expression in Digestive Organs of Mongolian Gerbils.

Mast cell (MC)-specific proteases are of particular interest for space biology and medicine due to their biological activity in regulating targets of a specific tissue microenvironment. MC tryptase and chymase obtain the ability to remodel connective tissue through direct and indirect mechanisms. Yet, MC-specific protease expression under space flight conditions has not been adequately investigated. Using immunohistochemical stainings, we analyzed in this study the protease profile of the jejunal, gastric, and hepatic MC populations in three groups of Mongolian gerbils-vivarium control, synchronous experiment, and 12-day orbital flight on the Foton-M3 spacecraft-and in two groups-vivarium control and anti-orthostatic suspension-included in the experiment simulating effects of weightlessness in the ground-based conditions. After a space flight, there was a decreased number of MCs in the studied organs combined with an increased proportion of chymase-positive MCs and MCs with a simultaneous content of tryptase and chymase; the secretion of specific proteases into the extracellular matrix increased. These changes in the expression of proteases were observed both in the mucosal and connective tissue MC subpopulations of the stomach and jejunum. Notably, the relative content of tryptase-positive MCs in the studied organs of the digestive system decreased. Space flight conditions simulated in the synchronous experiment caused no similar significant changes in the protease profile of MC populations. The space flight conditions resulted in an increased chymase expression combined with a decreased total number of protease-positive MCs, apparently due to participating in the processes of extracellular matrix remodeling and regulating the state of the cardiovascular system.

Increased Chymase-Positive Mast Cells in High-Grade Mucoepidermoid Carcinoma of the Parotid Gland

It has long been known that high-grade mucoepidermoid carcinoma (MEC) has a poor prognosis, but the detailed molecular and biological mechanisms underlying this are not fully understood. In the present study, the pattern of chymase-positive mast cells, as well as chymase gene expression, in high-grade MEC was compared to that of low-grade and intermediate-grade MEC by using 44 resected tumor samples of MEC of the parotid gland. Chymase expression, as well as chymase-positive mast cells, was found to be markedly increased in high-grade MEC. Significant increases in PCNA-positive cells and VEGF gene expression, as well as lymphangiogenesis, were also confirmed in high-grade MEC. Chymase substrates, such as the latent transforming growth factor-beta (TGF-β) 1 and pro-matrix metalloproteinase (MMP)-9, were also detected immunohistologically in high-grade MEC. These findings suggested that the increased chymase activity may increase proliferative activity, as well as metastasis in the malignant condition, and the inhibition of chymase may be a strategy to improve the poor prognosis of high-grade MEC of the parotid gland.

Features of the Distribution of Mast Cell Populations in Lungs and Spleen During Simulated Hypoxic Hypoxia

The aim of research was to study the distribution of mast cell populations in the lungs and spleen depending on their expression of proteases in normal conditions and different periods of simulated hypoxic hypoxia.Material and methods. Hypoxic hypoxia was modeled on 87 outbred male rats using 200 liter chambers. The animals were under experimental conditions for four months. Rats were removed from the experiment after 30, 60, 90 and 120 days. After the animals were removed from the experiment, the lungs and the spleen were removed and fixed in 10% neutral buffer solution of Labiko formalin. Lung and spleen preparations were stained with hematoxylin and eosin and according to Van Gieson. For immunohistochemical studies, a panel of monoclonal antibodies was used: Anti-Mast Cell Tryptase antibody, Anti-Mast Cell Chymase antibody.Results. When modeling hypoxia in the structures of the lungs at the terms of 30 and 60 days, the content of predominantly tryptase-positive cells increased, and by the 90th and 120th days, the content of chymase-positive cells increased. By the end of the experimental exposure, the number of tryptase-positive cells increased by 3 times, and chymase-positive – by 7,7 times compared with the control. As the duration of the experiment increased, the presence of tryptase-positive cells in the spleen increased by 3,5 times, chymase-positive cells – by 7 times in the structures of the red and white pulp.Conclusion. During the formation of chronic hypoxic hypoxia in the body of laboratory animals, there is a redistribution of mast cells expressing tryptase and chymase. The most significant increase in the number of chymase-positive mast cells was noted both in the lungs and in the spleen.

House Dust Mite and Cat Dander Extract Induce Asthma-Like Histopathology with an Increase of Mucosal Mast Cells in a Guinea Pig Model.

Asthma is a chronic inflammatory disease with structural changes in the lungs defined as airway remodelling. Mast cell responses are important in asthma as they, upon activation, release mediators inducing bronchoconstriction, inflammatory cell recruitment, and often remodelling of the airways. As guinea pigs exhibit anatomical, physiological, and pharmacological features resembling human airways, including mast cell distribution and mediator release, we evaluated the effect of extracts from two common allergens, house dust mite (HDM) and cat dander (CDE), on histopathological changes and the composition of tryptase- and chymase-positive mast cells in the guinea pig lungs. Guinea pigs were exposed intranasally to HDM or CDE for 4, 8, and 12 weeks, and airway histology was examined at each time point. Hematoxylin and eosin, Picro-Sirius Red, and Periodic Acid-Schiff staining were performed to evaluate airway inflammation, collagen deposition, and mucus-producing cells. In addition, Astra blue and immunostaining against tryptase and chymase were used to visualize mast cells. Repetitive administration of HDM or CDE led to the accumulation of inflammatory cells into the proximal and distal airways as well as increased airway smooth muscle mass. HDM exposure caused subepithelial collagen deposition and mucus cell hyperplasia at all three time points, whereas CDE exposure only caused these effects at 8 and 12 weeks. Both HDM and CDE induced a substantial increase in mast cells after 8 and 12 weeks of challenges. This increase was primarily due to mast cells expressing tryptase, but not chymase, thus indicating mucosal mast cells. We here show that exposure to HDM and CDE elicits asthma-like histopathology in guinea pigs with infiltration of inflammatory cells, airway remodelling, and accumulation of primarily mucosal mast cells. The results together encourage the use of HDM and CDE allergens for the stimulation of a clinically relevant asthma model in guinea pigs.

A Role for Mast Cell-Mediated Antibodies in the Formation of Cholesteatoma and Cholesteatoma-Induced Bone Erosion.

The study aimed to evaluate the effects and relationships between mast cells in the matrix, mast cell enzymes tryptase and chymase, epithelial proliferation, microvascular density, and bone destruction in cholesteatoma. Thirty-five biopsies diagnosed with cholesteatoma and seven healthy skin tissues taken from the retro-auricular region for control were evaluated. Immunohistochemical studies were performed with CD117, CD34, Ki-67, chymase, and tryptase antibodies, in a single session for all cases and the control group. The relationship between erosion size and antibody load was determined. The mean cholesteatoma epithelium Ki-67 was higher than the control group (p < 0.001). CD117-positive mast cells, chymase-positive mast cells, tryptase-positive mast cells, and microvessel density were significantly higher in the cholesteatoma matrix compared to the control group (p < 0.002, p < 0.001, p < 0.005). In the group with bone erosion scores of two and above, immunohistochemical markers tended to be higher. A positive correlation was found between CD117 and chymase, tryptase, and microvessel density; between tryptase, chymase, and microvessel density; and between chymase and microvessel density. CD117-positive mast cells and chymase-positive mast cells stimulate angiogenesis, increase the epithelium's proliferative capacity in the cholesteatoma matrix, and form cholesteatoma. The increased proliferation of cholesteatoma epithelium and increased vascular density in the matrix exacerbate bone erosion.

Human milk oligosaccharide disialyllacto-n-tetraose protects human intestinal epithelium integrity and permeability against mast cell chymase-induced disruption by stabilizing ZO-1/FAK/P38 pathway of intestinal epithelial cell

Context Inflammatory bowel disease (IBD) is a chronic gut disease with intestinal-epithelium disruption. Mast cell (MC) has been discussed in IBD studies, but its subset MCTC (chymase/tryptase) and MC-chymase have not been well-explored extensively. Human-milk-oligosaccharide-Disialyllacto-N-Tetraose (DSLNT) was reported as an effective strategy to protect infants against IBD with unclear mechanism. Objective This study was to examine the distribution of chymase-positive mast cells in the intestinal-epithelium-tissue of IBD infants, to explore the MC-chymase function on intestinal-epithelium, and to investigate the influences of DSLNT against MC-chymase-induced disruptions. Materials and Methods The intestinal-biopsies (surgical-waste) of the infants with IBD or with intestinal-atresia (non-IBD) were paraffin-embedded for immunohistochemistry. In-situ intestinal-tissue model and in-vitro human-intestinal-epithelial-cell (Caco-2) model were established with or without the treatments of MC-chymase (50mU/mL), DSLNT (600 µM) and DSLNT + MC-chymase respectively. The tissue morphology analysis, cell proliferation assay, cell-gap-closure assessment, fluorescence-immunocytochemistry, western blot, trans-epithelial-electrical-resistance, cell-cycle and statistical analysis were applied. Results There was an increased number of MCTC subset around the inflamed intestinal area in-vivo; MC-chymase caused intestinal-epithelial-barrier damage in-situ, decreased trans-epithelial-electrical-resistance of caco-2 cell monolayer in-vitro; while DSLNT protected epithelium against MC-chymase induced disruptions. MC-chymase reduced cell-viability, proliferation and migration, altered cell-cycle, down-regulated ZO-1, FAK, and P38 expressions, while DSLNT protected cells by impairing MC-chymase-induced interruptions. DSLNT can rescue ZO-1, FAK and P38 expressions and restore epithelial-cell integrity and cell cycle. Conclusions Chymase-positive MCs are involved in IBD progress. MC-chymase disrupts intracellular ZO-1/FAK/P38 signal pathway and cell-cell/cell-matrix contacts, while DSLNT protects intestinal-epithelium against MC-chymase to maintain the intestinal epithelium integrity.

Role of mast cells in the pathogenesis of severe lung damage in COVID-19 patients

BackgroundThere is still insufficient knowledge with regard to the potential involvement of mast cells (MCs) and their mediators in the pathology of coronavirus disease-2019 (COVID-19). Therefore, our study aimed to investigate the role of MCs, their activation and protease profiles in the pathogenesis of early and late lung damage in COVID-19 patients.MethodsFormalin-fixed and paraffin embedded lung specimens from 30 patients who died from COVID-19 and 9 controls were used for histological detection of MCs and their proteases (tryptase, chymase) followed by morphometric quantification.ResultsOur results demonstrated increased numbers of MCs at early stage and further augmentation of MCs number during the late stage of alveolar damage in COVID-19 patients, as compared to the control group. Importantly, the percentage of degranulated (activated) MCs was higher during both stages of alveolar lesions in comparison to the controls. While there was no prominent alteration in the profile of tryptase-positive MCs, our data revealed a significant elevation in the number of chymase-positive MCs in the lungs of COVID-19 patients, compared to the controls.ConclusionsMCs are characterized by dysregulated accumulation and increased activation in the lungs of patients suffering from COVID-19. However, future profound studies are needed for precise analysis of the role of these immune cells in the context of novel coronavirus disease.

Increase in Chymase-Positive Mast Cells in Recurrent Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma of the Parotid Gland.

Incomplete excision of pleomorphic adenoma (PA) may result in recurrent pleomorphic adenoma (RPA). Furthermore, long-term neglected PA may become carcinoma ex pleomorphic adenoma (CXPA). In the present study, the relationships between mast cell-derived chymase and these tumors were examined. The tumor tissues of PA consisted of either or both glandular and fibrotic structures. Histological features of RPA were almost similar to those of PA, except that they showed multinodular structures. CXPA is composed of a mixture of PA and carcinoma. The main stromal cells in PA were myofibroblasts, whereas fibroblasts constituted the main cellular portion in the stromal tissue of RPA. Cancer-associated fibroblasts (CAFs) were present abundantly in CXPA. With increased VEGF expression, neovascularization tended to increase in RPA or CXPA. Compared with PA, chymase-positive mast cells, as well as chymase gene expression, were increased in the tumor tissues from patients with RPA or CXPA. SCF, TGFβ1, and PCNA-positive staining was widely observed in these tumor tissues. The above results suggest that mast cell-derived chymase through its direct or cooperative effects with other mediators may participate in the pathophysiology of RPA and CXPA.

Chymase-positive Mast cells correlate with tumor angiogenesis: first report in pancreatic cancer patients.

Mast cells (MCs) are known to be involved in several physiological and pathological processes in humans and animals. Recently, their potential role in tumor development and angiogenesis has been investigated, arising interesting results to be potentially applied in clinics. Mast cells' granules contain a huge quantity of protease enzymes that, through different mechanisms, induce the formation of new microvessels, feeding tumor burden. Among them, tryptase and chymase are the most abundant enzymes: tryptase is well known for its multiple activities, on the contrary, the role of chymase in pancreatic cancer angiogenesis has not been investigated yet. Our research aims to correlate to each other and to angiogenesis four different tissue parameters (MCs density positive to chymase, MCs area positive to chymase, microvascular density and endothelial area) together with the main clinical-pathological characteristics in 52 patients surgically resected for pancreatic ductal adenocarcinoma, employing immunohistochemistry and image analysis system. All reported tissue parameters match to confirm the correlation between chymase enzyme and angiogenesis in pancreatic cancer. This evidence could become a starting point for a new potential therapeutic route exploiting chymase inhibitors as a novel anti-angiogenetic strategy in pancreatic cancer patients.

Evaluation of New Immunohistochemical Approaches for the Study of Kidney Tumors in Geriatric.

Kidney malignancies are among the most deadly genitourinary tumors. It is more common in males and is often seen in people aged 60-70 years old. The incidence rate of kidney cancer seems to be increasing. One reason for this may be the fact that imaging techniques, such as computed tomography scans are more commonly used. These tests may lead to the accidental detection of more kidney cancers. Fortunately, kidney cancer is often detected in the early stages, when the tumor is small and confined to the kidney. The objective of this study was the development of new diagnostic immunohistochemical methods. Clinical examination material of 134 people, including 94 (70%) males and 40 (30%) females, were used in this study. Immunohistochemical staining of tryptase was carried out in compliance with the requirements using Anti-Mast Cell Tryptase antibodies. Goat anti-mouse antibodies #AS-M1-HRP were used as secondary antibodies, visualized with ImmPACTTM DAB Peroxidase Substrate Kit (#SK-4105) according to the instructions of the manufacturer. The nuclei were counterstained with Mayer's hematoxylin, and the sections were embedded in a permanent mounting medium.The immunohistochemical study showed an increase in both tryptase- and chymase-positive mast cells in the renal parenchyma, compared with the control group. The number of mast cells with tryptase expression directly in the tumor was significantly less than the peritumoral localization. A similar pattern was observed for chymase-positive mast cells as the content of the tumor was more than 10 times higher than the intratumoral arrangement. The histological and immunological characteristics did not differ in different age groups. The immunohistochemical method of research in the diagnosis of renal tumors plays an important diagnostic and prognostic value. It can assist pathologists in difficult and ambiguous cases to correctly diagnose renal tumors. This will make it possible to prescribe the correct treatment and predict the course of malignant tumor growth in patients.

Biogenesis and secretory pathways of mast cell chymase: structural and functional aspects

Chymase is a specific protease of mast cells (MC) with variable expression and is one of the preformed components of the secre-tome. Chymase biogenesis begins with the processes of transcription in the nucleus, continuing in the cytoplasm of MC on ribosomes and in the cisterna of the endoplasmic reticulum. Entering the Golgi complex, molecules of the prochymase undergo post-translational modifications, this continuing in the vesicles detached from trans Golgi network. During further processing under granules maturation, chymase becomes an active enzyme and undergoes in-tragranular accumulation with typical topographic regularities, determining the features of the cytological and ultrastructural phenotype of MC. Various secretory mechanisms of chymase excretion into the extracellular matrix result in the development of diverse biological effects due to high selectivity of the protease to the molecular targets of cellular and extracellular components of the specific tissue microenvironment. Since chymase is an important enzyme in the formation of the state of the integrative-buffer metabolic environment of connective tissue, it is advisable to consider it as a diagnostic marker and a probable pharmacological target in the treatment of a number of pathological conditions. The involvement of chymase in the mechanisms of inflammation and allergy, angiogenesis and oncogenesis, remodeling of the extracellular matrix of connective tissue and changes in the histoarchitectonics of organs is also known. The technology of immunohistochemical staining using chro-mogenic or fluorescence detection allows objectively determining the number of chymase-positive MCs in the intraorgan population, the mechanisms of biogenesis and processing, cyto- and histoto-pographic characteristics with visualization of secretory pathways. Thus, the morphological identification of chymase significantly expands the interpretation of the data obtained in the study of adaptive and pathological states of internal organs, claiming not only diagnostic value, but also an assessment of the therapy performed.

A Histochemical and Immunohistochemical Study on Glandula Mandibularis Mast Cells in Angora Goat

Mast cells are particularly in association with structures, especially the skin, respiratory, and digestive systems in proximity to surfaces that interface with the external environment. This study was carry out to demonstrate the distribution and heterogeneity of mast cells in the Angora goat glandula mandibularis by using morphological, histochemical, and immunohistochemical methods. A total of seven healthy male adult Angora goats' mandibular glands were studied. Mast cells were distinctly distinguished by their metachromatic staining in preparates stained with toluidine blue. The cells were observed in various sizes and shapes, especially round, oval, and elongate-shaped. Mast cells were seen in both intralobular and interlobular interstitium in glandula mandibularis. Many mast cells were observed in the interlobular interstitium, especially around the blood vessels. The Alcian-blue/Safranin O combined staining method was used to determine mast cell heterogeneity. In glandula mandibularis, blue-colored alcian-blue (AB) (+) and pink-red colored safranin O (SO) (+) mast cell subtypes were observed. Chymase positive mast cells were usually observed one by one in both intralobular and interlobular interstitium. As a result, the mandibular gland of Angora goat which is local species was examined; the morphology, locations, heterogeneity of mast cells, and chymase expression were specified.

Disruption in the balance between apolipoprotein A-I and mast cell chymase in chronic hypersensitivity pneumonitis.

BackgroundApolipoprotein A‐I (apoA‐I) has an antifibrotic effect in idiopathic pulmonary fibrosis. Although pulmonary fibrosis is associated with poor prognosis of patients with hypersensitivity pneumonitis (HP), little is known regarding the role of apoA‐I in the pathogenesis of HP.MethodsTwo‐dimensional electrophoresis, immunoblotting, and enzyme‐linked immunosorbent assays were performed for the identification and quantification of apoA‐I in bronchoalveolar lavage fluid (BALF) from patients with acute and chronic HP. To investigate the degradation of apoA‐I, apoA‐I was incubated with BALF. Moreover, the role of apoA‐I in TGF‐β1‐induced epithelial–mesenchymal transition of A549 cells was examined.ResultsThe concentration of apoA‐I in the BALF was significantly lower in chronic HP (n = 56) compared with acute HP (n = 31). The expression level of apoA‐I was also low in the lung tissues of chronic HP. ApoA‐I was degraded by BALF from HP patients. The number of chymase‐positive mast cells in the alveolar parenchyma was inversely correlated with apoA‐I levels in the BALF of chronic HP patients. In vitro experiment using A549 cells, untreated apoA‐I inhibited TGF‐β1‐induced epithelial–mesenchymal transition, although this trend was not observed in the chymase‐treated apoA‐I.ConclusionsA decrease of apoA‐I was associated with the pathogenesis of chronic HP in terms of pulmonary fibrosis and mast cell chymase attenuated the protective effect of apoA‐I against pulmonary fibrosis. Furthermore, apoA‐I could be a crucial molecule associated with lung fibrogenesis of HP.

Mast cells profiles and heterogeneity in lipopolysaccharide-induced uveitis model

Backgound: Uveitis is an important inflammation of the middle tunica of the eye which can lead to blindness. Mast cells (MCs) participate in the development of the inflammatory process by attracting other cell types. Methods: The MCs profile was evaluated in the endotoxin-induced uveitis model (EIU), in the acute (24 hours) and late (48 hours) phases of the inflammatory process. EIU was induced by inoculation of lipopolysaccharide, subcutaneously, into the paw of the rats. After 24 and 48 hours of the induction, the eyes were enucleated for paraffin inclusion and histopathological studies of MCs in the anterior chamber of the eye. MCs were morphologically evaluated using Toluidine blue dye, their histamine accumulation was analyzed by Alcian blue and Safranin-O method, and the presence of tryptase and chymase by immunohistochemistry. Results: The results showed larger amount of total and degranulated MCs, as well as Alcian blue and Safranin positive MCs in the acute phase of EIU, especially in the ciliary body. Few tryptase positive MCs were observed in acute and late phases of EIU, but numerous chymase positive MCs were found in the 24-hour group. Conclusions: The data highlight the MC modulation during EIU and indicate these cells closely linked to the inflammatory process in uveitis.

Mast cell chymase: morphofunctional characteristics.

During degranulation, mast cells secrete a specific set of mediators defined as "secretome" including the preformed mediators that have already been synthesized by a cell and contained in the cytoplasmic granules. This group includes serine proteases, in particular, chymase and tryptase. Biological significance of chymase depends on the mechanisms of degranulation and is characterized by selective effects on the cellular and non-cellular components of the specific tissue microenvironment. Chymase is known to be closely involved in the mechanisms of inflammation and allergy, angiogenesis, and oncogenesis, remodeling of the extracellular matrix of the connective tissue and changes in organ histoarchitectonics. Number of chymase-positive mast cells in the intra-organ population, and the mechanisms of biogenesis and secretome degranulation appear to be the informative criteria for interpreting the state of the internal organs, characterizing not only the diagnostic efficacy but also the properties of targets of pharmacotherapy. In this review, we discussed the current state of knowledge about mast cell chymase as one of the mast cell secretome proteases. Main issues of the reviewed publications are highlighted with our microscopic images of mast cell chymase visualized using immunohistochemical staining.

Mechanical stress-induced mast cell degranulation activates TGF-β1 signalling pathway in pulmonary fibrosis

BackgroundThe role of mast cells accumulating in idiopathic pulmonary fibrosis (IPF) lungs is unknown.ObjectivesWe investigated the effect of fibrotic extracellular matrix (ECM) on mast cells in experimental and human pulmonary...