Mast cells in oral lichen planus and oral lichenoid lesions related to dental amalgam contact.

The aim of this study was to analyze the expression of mast cell markers toluidine blue, c-kit, and tryptase and presence of mononuclear inflammatory cells in oral lichen planus (OLP) and oral lichenoid lesions related to dental amalgam. Nineteen specimens of OLP, OLLC, and healthy oral mucosa were selected. Mononuclear inflammatory cells were analyzed. Histochemical and immunohistochemical analyses were performed using toluidine blue, anti-c-kit and anti-tryptase reagents, and the results were quantified in areas A and B of connective tissue. Mast cells of all OLP and OLLC samples were positive for toluidine blue, c-kit, and tryptase. The density of toluidine blue+, c-kit+ and tryptase+ mast cells was higher in tissue with OLP and OLLC compared with healthy controls (p < 0.05). No difference was noted in mast cells density between OLP and OLLC (p > 0.05). The density of tryptase+ mast cells was higher in the subepithelial region (area A) than the region below it (Area B) in OLLC (p = 0.047). The mononuclear inflammatory cell density was higher in OLLC compared to OLP, but without statistical significance (p > 0.05). A positive statistical correlation was found between mononuclear immune cells and density of c-kit+ and tryptase+ mast cells in OLP (r = 0.943 and r = 0.886, respectively). Our data demonstrate that the etiopathogenesis process of OLP and OLLC modulates the expansion and degranulation of mast cells; mast cells density, however, was similar between OLP and OLLC. The distribution of mast cells appears to vary along the lamina propria.

Evaluation of peripheral nerve fibers and mast cells in burning mouth syndrome.

Emerging evidence has revealed a cross-talk in the etiopathogenesis of burning mouth syndrome (BMS) related to peripheral nerve fibers (NF) and neuropeptides secreted by mast cells. Here, we investigated the S-100+ density and PGP 9.5+ integrity of peripheral NF and the tryptase+ mast cell density in the oral mucosa of BMS patients and healthy individuals. A total of 23 oral mucosa specimens (12 BMS and 11 controls) were evaluated. The clinical diagnosis of BMS was based on a careful examination, excluding other local and systemic causes. Samples were taken from an incisional biopsy of the tongue mucosa of individuals with symptomatic BMS, while the margins of the non-neoplastic tongue biopsy served as controls of healthy individuals. Immunohistochemistry was performed to determine the density/mm2 of S-100+, PGP 9.5+ peripheral NF, and tryptase+ mast cells. Similar densities of S-100+, PGP 9.5+ peripheral NF, and tryptase+ mast cells were found in cases of BMS, with a median value of 3.70, 0.70, and 29.24/mm2, respectively, and in the control group, with a median value of 2.60, 0.80, and 26.01/mm2, respectively (p > 0.05). Moreover, the relationship between S100+ and PGP 9.5+ peripheral NF was the same in both groups (p = 0.70). This study demonstrated that there were no alterations in the density and integrity of peripheral NF in the tongue of symptomatic BMS patients. However, the sensitization of peripheral NF in this disease may not depend on mast cell density.

The pathogenic role of c-Kit+ mast cells in the spinal motor neuron-vascular niche in ALS.

Degeneration of motor neurons, glial cell reactivity, and vascular alterations in the CNS are important neuropathological features of amyotrophic lateral sclerosis (ALS). Immune cells trafficking from the blood also infiltrate the affected CNS parenchyma and contribute to neuroinflammation. Mast cells (MCs) are hematopoietic-derived immune cells whose precursors differentiate upon migration into tissues. Upon activation, MCs undergo degranulation with the ability to increase vascular permeability, orchestrate neuroinflammation and modulate the neuroimmune response. However, the prevalence, pathological significance, and pharmacology of MCs in the CNS of ALS patients remain largely unknown. In autopsy ALS spinal cords, we identified for the first time that MCs express c-Kit together with chymase, tryptase, and Cox-2 and display granular or degranulating morphology, as compared with scarce MCs in control cords. In ALS, MCs were mainly found in the niche between spinal motor neuron somas and nearby microvascular elements, and they displayed remarkable pathological abnormalities. Similarly, MCs accumulated in the motor neuron-vascular niche of ALS murine models, in the vicinity of astrocytes and motor neurons expressing the c-Kit ligand stem cell factor (SCF), suggesting an SCF/c-Kit-dependent mechanism of MC differentiation from precursors. Mechanistically, we provide evidence that fully differentiated MCs in cell cultures can be generated from the murine ALS spinal cord tissue, further supporting the presence of c-Kit+ MC precursors. Moreover, intravenous administration of bone marrow-derived c-Kit+ MC precursors infiltrated the spinal cord in ALS mice but not in controls, consistent with aberrant trafficking through a defective microvasculature. Pharmacological inhibition of c-Kit with masitinib in ALS mice reduced the MC number and the influx of MC precursors from the periphery. Our results suggest a previously unknown pathogenic mechanism triggered by MCs in the ALS motor neuron-vascular niche that might be targeted pharmacologically.

Involvement of tryptase-positive mast cells and angiogenesis in the growth of inflammatory odontogenic cysts.

Inflammatory periapical lesions are characterized by infiltration of different immune cell types, the functions of which depend on an effective vascular network. This study aimed to evaluate the mast cells density (MCD) in inflamatory odontogenic cysts capsules concerning microvascular density (MVD), microvascular area (MVA), and microvascular perimeter (MVP), and correlate such findings with the type of lesion, intensity of the inflammatory infiltrate, and thickness of the epithelial lining. Twenty inflamatory dentigerous cysts (IDCs), twenty radicular cysts (RCs), and twenty residual radicular cysts (RRCs) were submitted to immunohistochemical analysis using anti-tryptase and anti-CD34 antibodies. RCs exhibited the highest MCD, MVD, MVA, and MVP indexes (p = < 0.001, p = 0.008, p = 0.003 and p = < 0.001, respectively), and lesions with inflammatory infiltrate grade III showed the highest MVD (p = 0.044). Considering epithelial thickness, a higher MVP index was identified in lesions with hyperplastic epithelium (p = 0.018). In IDCs, RCs, and RRCs, a strong positive correlation was observed between MVA and MVP (r = 0.950 and p = < 0.001; r = 0.914 and p = < 0.001; r = 0.713 and p = < 0.001, respectively). In IDCs, a moderate correlation was observed between MCD and both MVA and MVP (r = 0.660 and p = 0.002; r = 0.634 and p = 0.003, respectively). These results suggest that tryptase-positive mast cells might play an important role in the angiogenic activity of IDCs, while RCs had the highest indexes. Our findings also confirmed that the intensity of the inflammatory infiltrate and epithelial thickness influence angiogenesis.

Involvement of tryptase-positive mast cells and angiogenesis in the growth of inflammatory odontogenic cysts

Abstract: Inflammatory periapical lesions are characterized by infiltration of different immune cell types, the functions of which depend on an effective vascular network. This study aimed to evaluate the mast cells density (MCD) in inflamatory odontogenic cysts capsules concerning microvascular density (MVD), microvascular area (MVA), and microvascular perimeter (MVP), and correlate such findings with the type of lesion, intensity of the inflammatory infiltrate, and thickness of the epithelial lining. Twenty inflamatory dentigerous cysts (IDCs), twenty radicular cysts (RCs), and twenty residual radicular cysts (RRCs) were submitted to immunohistochemical analysis using anti-tryptase and anti-CD34 antibodies. RCs exhibited the highest MCD, MVD, MVA, and MVP indexes (p = < 0.001, p = 0.008, p = 0.003 and p = < 0.001, respectively), and lesions with inflammatory infiltrate grade III showed the highest MVD (p = 0.044). Considering epithelial thickness, a higher MVP index was identified in lesions with hyperplastic epithelium (p = 0.018). In IDCs, RCs, and RRCs, a strong positive correlation was observed between MVA and MVP (r = 0.950 and p = < 0.001; r = 0.914 and p = < 0.001; r = 0.713 and p = < 0.001, respectively). In IDCs, a moderate correlation was observed between MCD and both MVA and MVP (r = 0.660 and p = 0.002; r = 0.634 and p = 0.003, respectively). These results suggest that tryptase-positive mast cells might play an important role in the angiogenic activity of IDCs, while RCs had the highest indexes. Our findings also confirmed that the intensity of the inflammatory infiltrate and epithelial thickness influence angiogenesis.

Differential expression of mast cell granules in samples of metastatic and non-metastatic colorectal cancer in patients.

Various cell types participate in the tumor process, in which the mast cells have been described; however, the role they play in colorectal adenocarcinoma has not yet been fully understood. Therefore, the present work aimed to compare employing histochemistry and immunohistochemistry, the number of mast cells and the content of some cytoplasmic granules in moderately differentiated non-metastatic and metastatic colorectal adenocarcinoma, analyzing tissue samples from patients. Histochemical techniques with Toluidine Blue (TBO), Periodic Schiff Acid (PAS), Alcian Blue/Periodic Acid-Schiff (PAB) and Alcian Blue/Safranin (ABS); as well as immunohistochemical reactions with anti-antibodies anti-Tryptase and anti-Chymase were applied to quantify total mast cells and content of some cytoplasmic granules. Statistical analysis was performed using SPSS V22.0 software (p ≤ 0.05). The degree of positivity of the reaction and degranulation of mast cells was reported in percentages. In our results, we observed that there are differences in the quantity and histochemical composition of the granules of mast cells (metastatic group PAS and ABS comparing the TBO reaction), as well as in the immunohistochemical composition between Tryptase and Chymase and the number of degranulated cells in both study groups (74 % degranulated mast cells in the metastatic group, 66 % integrate mast cells in the non-metastatic group). Therefore, we consider that the differences may be some of the probable factors that lead to metastasis of colorectal adenocarcinoma.

Effect of body mass index and rocuronium on serum tryptase concentration during volatile general anesthesia: an observational study.

OBJECTIVE: Female sex, body mass index (BMI), and neuromuscular blocking agents are risk factors of perioperative hypersensitivity reactions. This study aimed to investigate the effect of rocuronium on serum tryptase concentrations during general anesthesia in overweight and obese women. METHODS: The study was conducted in two groups: Group I (n=66) underwent volatile anesthesia with rocuronium and group II (n=60) underwent volatile anesthesia without any muscle relaxant. Serum tryptase concentration (STC) measurements were performed at baseline (STC 0) and postoperatively (STC 1). ClinicalTrials.gov: NCT04035707 RESULTS: The highest median value of STC 0 was seen in obese patients (3.44 µg L-1) and it was significantly higher than in overweight (p=0.01) and underweight patients (p=0.03). The maximum STC 0 was observed in overweight patients (20.4 µg L-1). In group I, STC 0 in obese patients presented the highest median value (4.49 µg L-1), and was significantly higher than in overweight patients (p=0.03), and had significantly higher STC 1 than patients with normal BMI (p=0.04). STC 0 and STC 1 in overweight and obese female patients did not differ significantly between groups. STC 1 did not correlate with rocuronium doses. In group I, BMI positively correlated with the duration of rocuronium infusion (rho=0.37) and STC 1 positively correlated with BMI (rho=0.32). CONCLUSION: Excess weight and obesity predispose to higher preoperative serum tryptase values. Postoperative STC is not linked to rocuronium doses. BMI is the main determinant factor of STC during combined volatile general anesthesia.

A role for mast cells and mast cell tryptase in driving neutrophil recruitment in LPS-induced lung inflammation via protease-activated receptor 2 in mice.

OBJECTIVE: This study aims to investigate the role of protease-activated receptor (PAR) 2 and mast cell (MC) tryptase in LPS-induced lung inflammation and neutrophil recruitment in the lungs of C57BL/6 mice. METHODS: C57BL/6 mice were pretreated with the PAR2 antagonist ENMD-1068, compound 48/80 or aprotinin prior to intranasal instillation of MC tryptase or LPS. Blood leukocytes, C-X-C motif chemokine ligand (CXCL) 1 production leukocytes recovered from bronchoalveolar lavage fluid (BALF), and histopathological analysis of the lung were evaluated 4 h later. Furthermore, we performed experiments to determine intracellular calcium signaling in RAW 264.7 cells stimulated with LPS in the presence or absence of a protease inhibitor cocktail or ENMD-1068 and evaluated PAR2 expression in the lungs of LPS-treated mice. RESULTS: Pharmacological blockade of PAR2 or inhibition of proteases reduced neutrophils recovered in BALF and LPS-induced calcium signaling. PAR2 blockade impaired LPS-induced lung inflammation, PAR2 expression in the lung and CXCL1 release in BALF, and increased circulating blood neutrophils. Intranasal instillation of MC tryptase increased the number of neutrophils recovered in BALF, and MC depletion with compound 48/80 impaired LPS-induced neutrophil migration. CONCLUSION: Our study provides, for the first time, evidence of a pivotal role for MCs and MC tryptase in neutrophil migration, lung inflammation and macrophage activation triggered by LPS, by a mechanism dependent on PAR2 activation.

Atualização sobre reações de hipersensibilidade perioperatória: Documento conjunto da Sociedade Brasileira de Anestesiologia e Associação Brasileira de Alergia e Imunologia ­ Parte II: etiologia e diagnóstico / Update on perioperative hypersensitivity reactions: Joint document from the Brazilian Society of Anesthesiology and Brazilian Association of Allergy and Immunology ­ Part II: Etiology and diagnosis

A anafilaxia perioperatória é manifestação importante no contexto de eventos adversos relacionados à cirurgia. Embora frequentemente relacionada à indução anestésica, pode ocorrer por outros agentes administrados por outras vias. A anafilaxia pode se apresentar como colapso cardiovascular, obstrução da via aérea e/ou insuficiência respiratória com ou sem manifestação cutânea, com consequências fatais em muito casos. Apesar de considerada inevitável em alguns casos, a sua incidência poderia (e deveria) ser reduzida através da busca por fármacos mais seguros. A avaliação abrangente de um episódio é um dos elementos primordiais para tornar a exposição subsequente mais segura, com orientações derivadas dessa investigação. Entretanto, representa um desafio estatístico por ser reação rara, randômica e muitas vezes independente de exposições sucessivas dos pacientes a procedimentos de baixo risco. Neste documento são revisados os mecanismos fisiopatológicos, agentes desencadeantes (adultos e crianças), assim como a abordagem diagnóstica durante a crise e após o episódio. Uma avaliação abrangente, a identificação das medicações, antissépticos e outras substâncias usadas em cada região, registros detalhados e nomenclatura padronizada são pontos fundamentais para a obtenção de dados epidemiológicos mais fidedignos sobre a anafilaxia perioperatória.

Perioperative anaphylaxis is an important manifestation in the context of surgery-related adverse events. Although often related to anesthetic induction, it may be caused by other agents administered by other routes. Anaphylaxis may manifest as cardiovascular collapse, airway obstruction and/or respiratory failure with or without skin manifestation, resulting often in death. Although this reaction is considered inevitable in some cases, its incidence could (and should) be reduced by the search for safer drugs. Comprehensive assessment of an allergic reaction is a key element to make subsequent exposure safer, with guidance derived from this investigation. However, surveillance of perioperative anaphylaxis represents a statistical challenge because this is a rare, random reaction and often independent of successive patient exposures to low-risk procedures. This paper reviews pathophysiological mechanisms, triggering agents (adults and children), as well as therapeutic and diagnostic approach during and after an allergic reaction. Comprehensive assessment, identification of medications/antiseptics used in each region and detailed records with standardized terminology are key points for obtaining more reliable epidemiological data on perioperative anaphylaxis.

Análise de células dendríticas, mastócitos e vascularização na doença periodontal biofilme induzida em idosos / Analysis of dendritic cells, mast cells and vasculature in biofilm-induced periodontal disease in the elderly

A microbiota e o sistema imune do idoso apresentam algumas alterações, favorecendo ao aparecimento de infecções e doenças inflamatórias. A doença periodontal é um exemplo, permeando entre fase imediata e tardia, pode ter alterações em sua evolução com o envelhecimento humano. Compreender a doença periodontal e sua relação com o ciclo da vida é importante para a prevenção, tratamento e cura. Este estudo tem como objetivo avaliar a quantidade de mastócitos (triptase), células dendríticas imaturas (CD1a), células dendríticas maduras (CD83) e vasos sanguíneos (CD34) em 154 tecidos periodontais saudáveis e doentes (27 idosos e 127 adultos). Foi utilizada a técnica de imunoistoquímica através da imunomarcação do CD1a, CD83, triptase e CD34, sendo contabilizados em 5 campos de maior número de células positivas, no aumento de 1000x. Para o CD34, ainda foram calculadas a área e o perímetro microvascular para todos os vasos sanguíneos presentes, e dos vasos com presença do endotélio vascular alto. Não houve diferença na imunomarcação das células dendríticas, dos mastócitos e na quantidade de vasos sanguíneos nos tecidos gengivais, entre os casos de gengiva clinicamente saudável, gengivite induzida por biofilme e periodontite estágios II, III e IV, avaliando isoladamente os grupos etários: adultos e idosos. As células dendríticas imaturas são mais numerosas no idoso com o quadro clínico de gengivite e periodontite. Os adultos com gengivite induzida por biofilme possuem maior quantidade de vasos sanguíneos que o grupo idoso. A área microvascular e o perímetro microvascular dos vasos sanguíneos com o endotélio vascular alto apresentaram maiores nos idosos nos casos de gengivite. Este estudo concluiu que nesta amostra não houve diferença na quantidade de células dendríticas imaturas e maduras, mastócitos na doença periodontal dentro dos grupos etário, porém as células dendríticas imaturas estão mais presentes no idoso podendo estar relacionado a algum decréscimo funcional. Em relação aos vasos sanguíneos, há presença de HEVs em adultos e idosos, não havendo diferença entre os diagnósticos. Nos idosos com gengivite há um aumento da área microvascular e perímetro microvascular, necessitando de estudos que justifiquem esta diferença (AU).

The elderly's microbiota and immune system show some changes, favoring the onset of infections and inflammatory diseases. Periodontal disease is an example, permeating between immediate and adaptative stages, it can have changes in its evolution with human aging. Understanding periodontal disease and its relationship with the life cycle is important for prevention, treatment and cure. This study aims to assess the amount of mast cells (tryptase), immature dendritic cells (CD1a), mature dendritic cells (CD83) and blood vessels (CD34) in 154 healthy and sick periodontal tissues (27 elderly and 127 adults). The immunohistochemistry technique was used through the immunostaining of CD1a, CD83, tryptase and CD34, being counted in 5 fields with a greater number of positive cells, in the 1000x increase. For CD34, the microvascular area and perimeter were also calculated for all blood vessels present, and for vessels with the presence of high vascular endothelium. There was no difference in the immunostaining of dendritic cells, mast cells and the amount of blood vessels in the gingival tissues, between cases of clinically healthy gingiva, biofilm-induced gingivitis and stages II, III and IV periodontitis, evaluating the age groups: adults and elderly. Immature dendritic cells are more numerous in the elderly with the clinical picture of gingivitis and periodontitis. Adults with biofilm-induced gingivitis have a greater amount of blood vessels than the elderly group. The microvascular area and the microvascular perimeter of the blood vessels with the high vascular endothelium were larger in the elderly in cases of gingivitis. This study concluded that in this sample there was no difference in the amount of immature and mature dendritic cells, mast cells in periodontal disease within the age groups, however, immature dendritic cells are more present in the elderly and may be related to some functional decrease. Regarding blood vessels, there are HEVs in adults and the elderly, with no difference between diagnoses. In the elderly with gingivitis there is an increase in the microvascular area and microvascular perimeter, requiring studies that justify this difference (AU).

Relationship between mast cells and E-cadherin in odontogenic keratocysts and radicular cysts.

OBJECTIVE: This study aimed to evaluate tryptase and E-cadherin protein expression in odontogenic keratocysts (OKCs) and radicular cysts (RCs) and their relationship with lesion size. MATERIALS AND METHODS: Thirty OKC and 30 RC cases were analyzed by immunohistochemistry. Tryptase expression was quantitatively assessed using the quantification of mast cells, and expression of E-cadherin was semi-quantitatively analyzed estimating the proportion of positive cells: 1 = less than 25% of immunopositive cells; 2 = 26 to 50% of immunopositive cells; 3 = 51 to 75% of immunopositive cells; 4 = more than 75% of immunopositive cells. Data on cystic lesion sizes were obtained from patients' clinical files, based on previous radiographic exams, and the lesions were categorized into three groups: group 1 (< 2 to 2 cm); group 2 (> 2 to 4 cm), and group 3 (> 4 cm). RESULTS: Higher mast cell means were found for RCs, with the predominance of degranulated mast cells in both OKCs and RCs (p = 0.082). Concerning the epithelial component, a higher concentration of degranulated mast cells was detected in RCs (p = 0.000). Regarding connective tissue, degranulated mast cells were more evident in OKCs (p = 0.762). A negative correlation was observed between E-cadherin expression and total number of mast cells (p = 0.011), degranulated mast cells (p = 0.040), and degranulated mast cells in both superficial (p = 0.035) and deep connective tissues (p = 0.009). Concerning lesion size, a negative correlation with total number of mast cells (p = 0.016) and number of degranulated mast cells (p = 0.049) was observed, both in the epithelial components. Herein, the larger the lesion size, the lower the number of degranulated mast cells in the epithelium (r = - 0.271; p = 0.49), suggesting that these cells play a role in the initial cystic expansion phase. CONCLUSION: The higher expression of tryptase in degranulated mast cells was linked to a lower expression of E-cadherin, which may be related to a change in the epithelial permeability in these lesions, contributing to increased cystic content and lesion growth. CLINICAL RELEVANCE: Evidence of the relationship between mast cells and E-cadherin in the growth of odontogenic cysts was studied.

Effect of body mass index and rocuronium on serum tryptase concentration during volatile general anesthesia: an observational study

OBJECTIVE: Female sex, body mass index (BMI), and neuromuscular blocking agents are risk factors of perioperative hypersensitivity reactions. This study aimed to investigate the effect of rocuronium on serum tryptase concentrations during general anesthesia in overweight and obese women. METHODS: The study was conducted in two groups: Group I (n=66) underwent volatile anesthesia with rocuronium and group II (n=60) underwent volatile anesthesia without any muscle relaxant. Serum tryptase concentration (STC) measurements were performed at baseline (STC 0) and postoperatively (STC 1). ClinicalTrials.gov: NCT04035707 RESULTS: The highest median value of STC 0 was seen in obese patients (3.44 μg L-1) and it was significantly higher than in overweight (p=0.01) and underweight patients (p=0.03). The maximum STC 0 was observed in overweight patients (20.4 μg L-1). In group I, STC 0 in obese patients presented the highest median value (4.49 μg L-1), and was significantly higher than in overweight patients (p=0.03), and had significantly higher STC 1 than patients with normal BMI (p=0.04). STC 0 and STC 1 in overweight and obese female patients did not differ significantly between groups. STC 1 did not correlate with rocuronium doses. In group I, BMI positively correlated with the duration of rocuronium infusion (rho=0.37) and STC 1 positively correlated with BMI (rho=0.32). CONCLUSION: Excess weight and obesity predispose to higher preoperative serum tryptase values. Postoperative STC is not linked to rocuronium doses. BMI is the main determinant factor of STC during combined volatile general anesthesia.

Explanation for the signs and symptoms of tooth eruption: mast cells.

This study contributes to the understanding of the mechanisms associated with signs and symptoms of tooth eruption, by investigating the presence of mast cells in pericoronal tissues during the intraosseous (Group 1) and submucosal (Group 2) phases of eruption. We compared findings for these two groups with each other and with those for the oral mucosa (Group 3). In each group, 14 specimens were analyzed microscopically after hematoxylin and eosin staining and immunohistochemical analysis of c-Kit and tryptase expression. Results revealed that the number and density of mast cells is different in follicular tissues according to the eruption phase, which may mean that: 1) masticatory trauma of the oral mucosa and dental follicles in the submucosa may explain why reduced enamel epithelium exposes enamel to the cells of the connective tissue; 2) exposure of antigenic enamel proteins might correspond to the release of sequestered antigens, which may lead to the interaction of IgE and a greater number of mast cells in the region; and 3) the consequent degranulation and the local release of mediators, such as histamine, leukotrienes, prostaglandins, proteases, cytokines and growth factors, contribute to the understanding of signs and symptoms associated with tooth eruption.

Mast Cell Protease 7 Promotes Angiogenesis by Degradation of Integrin Subunits.

Previous studies from our laboratory have shown that during angiogenesis in vitro, rmMCP-7 (recombinant mouse mast cell protease-7) stimulates endothelial cell spreading and induces their penetration into the matrix. The ability of rmMCP-7 to induce angiogenesis in vivo was assessed in the present study using a directed in vivo angiogenesis assay (DIVAA™). Vessel invasion of the angioreactor was observed in the presence of rmMCP-7 but was not seen in the control. Since integrins are involved in endothelial cell migration, the relationship between rmMCP-7 and integrins during angiogenesis was investigated. Incubation with rmMCP-7 resulted in a reduction in the levels of integrin subunits αv and ß1 on SVEC4-10 endothelial cells during angiogenesis in vitro. Furthermore, the degradation of integrin subunits occurs both through the direct action of rmMCP-7 and indirectly via the ubiquitin/proteasome system. Even in the presence of a proteasome inhibitor, incubation of endothelial cells with rmMCP-7 induced cell migration and tube formation as well as the beginning of loop formation. These data indicate that the direct degradation of the integrin subunits by rmMCP-7 is sufficient to initiate angiogenesis. The results demonstrate, for the first time, that mMCP-7 acts in angiogenesis through integrin degradation.

Explanation for the signs and symptoms of tooth eruption: mast cells

Abstract This study contributes to the understanding of the mechanisms associated with signs and symptoms of tooth eruption, by investigating the presence of mast cells in pericoronal tissues during the intraosseous (Group 1) and submucosal (Group 2) phases of eruption. We compared findings for these two groups with each other and with those for the oral mucosa (Group 3). In each group, 14 specimens were analyzed microscopically after hematoxylin and eosin staining and immunohistochemical analysis of c-Kit and tryptase expression. Results revealed that the number and density of mast cells is different in follicular tissues according to the eruption phase, which may mean that: 1) masticatory trauma of the oral mucosa and dental follicles in the submucosa may explain why reduced enamel epithelium exposes enamel to the cells of the connective tissue; 2) exposure of antigenic enamel proteins might correspond to the release of sequestered antigens, which may lead to the interaction of IgE and a greater number of mast cells in the region; and 3) the consequent degranulation and the local release of mediators, such as histamine, leukotrienes, prostaglandins, proteases, cytokines and growth factors, contribute to the understanding of signs and symptoms associated with tooth eruption.

Resumo Para contribuir com a compreensão dos mecanismos relacionados à sintomatologia e aos sinais associados à erupção dentária, investigou-se a presença de mastócitos nos tecidos pericoronários na fase intraóssea (Grupo 1) e submucosa (Grupo 2), comparando-os entre si e com a mucosa bucal (Grupo 3). Em cada grupo, 14 espécimes foram analisados microscopicamente em cortes corados com hematoxilina e eosina, e imunocitoquimicamente marcados com Ckit e Triptase. Pelos resultados obtidos, concluiu-se que a quantidade/densidade dos mastócitos é diferente nos tecidos foliculares de acordo com a fase de erupção, o que permite inferir que: 1) O traumatismo decorrente da mastigação sobre o conjunto "mucosa bucal com o folículo pericoronário na submucosa" pode explicar porque o epitélio reduzido exporia o esmalte às células do tecido conjuntivo; 2) A exposição das proteínas do esmalte com propriedades antigênicas corresponderia à liberação de antígenos sequestrados que levariam à interação de IgE e mastócitos em número aumentado na região; e 3) A consequente degranulação e liberação de mediadores no local, como histamina, leucotrienes, prostaglandinas, proteases, citocinas e fatores de crescimento, contribuem para a compreensão dos sinais e sintomatologia atribuídos à erupção dentária.

Serum Baseline Tryptase Level as a Marker for the Severity of Anaphylaxis.

BACKGROUND: Anaphylaxis is a severe and potentially fatal allergic disease or hypersensitivity reaction with variable clinical presentation. Biomarkers in anaphylaxis could be useful to improve diagnosis, to allow endotyping of patients, and to predict risk. OBJECTIVE: To investigate the role of serum basal tryptase (sBT) levels in the management of patients with anaphylaxis. METHODS: Patients with at least 1 episode of anaphylaxis were selected among those who attended the Allergy Clinics of the Clinical Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil, upon evaluation by allergy/immunology specialists of our medical staff. Demographic and clinical data were obtained using a structured questionnaire. sBT levels were determined using the ImmunoCAP Tryptase immunoassay. RESULTS: 57 patients (56.1% female) with a median age of 35 years (range 7-87 years) participated in the study. sBT levels ranged from 2.57 to 21.19 ng/mL (mean 5.17 ng/mL), with no significant differences in patients with anaphylaxis due to different triggers. Mean levels were 4.93; 5.2; 5.41, and 5.24 ng/mL for patients who had anaphylaxis due to Hymenoptera venom (n = 17), foods (n = 13), drugs (n = 13), and idiopathic disease (n = 14), respectively. Significantly higher sBT levels were observed in patients with severe anaphylaxis (grade IV) than in patients with mild-moderate disease (grades II/III) (mean levels 6.61 vs. 4.71 ng/mL, respectively). CONCLUSION: High sBT levels may help to identify patients at increased risk of more severe anaphylaxis, prompting physicians to initiate immediate therapy to avoid further acute episodes.

Vasoactive intestinal peptide degradation might influence Interleukin-17 expression in cardiac chagasic patients.

The vasoactive intestinal peptide (VIP) expression is lower in cardiac chagasic patients and is related to worse cardiac function. The reduction of VIP in patients with Chagas disease may be a result of its enhanced degradation. To test this hypothesis, the tryptase and chymase expression was evaluated. We also related VIP levels with interleukin-17 (IL-17) expression since VIP may modulate IL-17 production. Plasma levels of chymase were higher in chagasic patients. Conversely, VIP/chymase and VIP/tryptase ratios were lower in chagasic patients when compared to non-infected individuals. Besides, the VIP/chymase ratio was lower in chagasic cardiac patients in comparison with the indeterminate group. A positive correlation between tryptase and chymase levels was observed in chagasic cardiac patients. In relation to IL-17, we observed a higher expression of this cytokine in the cardiac form of the disease than in the indeterminate form. IL-17/VIP ratio was higher in the cardiac form in comparison with non-infected or indeterminate form. These results suggest that the low levels of VIP observed in chagasic patients could be due to an increased production of chymase and/or to the additive effect of the interaction between chymase and tryptase in the cardiac form. Moreover, the decreased VIP expression may contribute to the increase of IL-17 in chagasic cardiac patients.

Mycobacterium tuberculosis Catalase Inhibits the Formation of Mast Cell Extracellular Traps.

Tuberculosis is one of the leading causes of human morbidity and mortality. Mycobacterium tuberculosis (Mtb) employs different strategies to evade and counterattack immune responses persisting for years. Mast cells are crucial during innate immune responses and help clear infections via inflammation or by direct antibacterial activity through extracellular traps (MCETs). Whether Mtb induce MCETs production is unknown. In this study, we report that viable Mtb did not induce DNA release by mast cells, but heat-killed Mtb (HK-Mtb) did. DNA released by mast cells after stimulation with HK-Mtb was complexed with histone and tryptase. MCETs induced with PMA and HK-Mtb were unable to kill live Mtb bacilli. Mast cells stimulated with HK-Mtb induced hydrogen peroxide production, whereas cells stimulated with viable Mtb did not. Moreover, MCETs induction by HK-Mtb was dependent of NADPH oxidase activity, because its blockade resulted in a diminished DNA release by mast cells. Interestingly, catalase-deficient Mtb induced a significant production of hydrogen peroxide and DNA release by mast cells, indicating that catalase produced by Mtb prevents MCETs release by degrading hydrogen peroxide. Our findings show a new strategy employed by Mtb to overcome the immune response through inhibiting MCETs formation, which could be relevant during early stages of infection.

Mast Cell, the Neglected Member of the Tumor Microenvironment: Role in Breast Cancer.

Mast cells are unique tissue-resident immune cells that secrete a diverse array of biologically active compounds that can stimulate, modulate, or suppress the immune response. Although mounting evidence supports that mast cells are consistently infiltrating tumors, their role as either a driving or an opposite force for cancer progression is still controversial. Particularly, in breast cancer, their function is still under discussion. While some studies have shown a protective role, recent evidence indicates that mast cells enhance blood and lymphatic vessel formation. Interestingly, one of the most important components of the mast cell cargo, the serine protease tryptase, is a potent angiogenic factor, and elevated serum tryptase levels correlate with bad prognosis in breast cancer patients. Likewise, histamine is known to induce tumor cell proliferation and tumor growth. In agreement, mast cell depletion reduces the size of mammary tumors and metastasis in murine models that spontaneously develop breast cancer. In this review, we will discuss the evidence supporting protumoral and antitumoral roles of mast cells, emphasizing recent findings placing mast cells as important drivers of tumor progression, as well as the potential use of these cells or their mediators as therapeutic targets.