Relationship between mast cell degranulation and inflammation in the oral cavity

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.

Effects of Violet and IR LED Light on mast cell degranulation: in vivo study in a murine model

The aim of this study was to evaluate the influence of IR (λ850 ± 10 nm) and violet (λ405 ± 10 nm) LED phototherapy on total mast cells counts and its ability to influence mast cell degranulation. For this, 27 Wistar rats were used and were randomly distributed into three groups: control, IR LED, and violet LED. When indicated, irradiation done and they were sacrificed, had their tongue removed immediately, 20-min, 45-min, and 2-h after irradiation. Samples were processed to wax, cut, and stained with Toluidine Blue. Intact and degranulated mast cells were counted under light microscopy, and statistical analysis was carried out. In the superficial connective tissue and muscular tissues, violet LED light caused a significant increase in both total number and degranulated mast cells when compared to the control group immediately after irradiation. The degranulation indexes were higher in the groups irradiated with Violet light, both in superficial connective tissue and muscular tissues in relation to the timing. Irradiation with IR LED caused immediate increase in the total number and degranulated of mast cells when compared to the control group only in the superficial connective tissue. In all times observed, the highest total amount of mast cells was seen immediately after irradiation, except in the muscular tissue, which presented the highest amount after 20-min. It was concluded that IR and violet LED light were able to increase the number of mast cells and inducing degranulation in oral mucosa. However, considering that violet LED light can be harmful in periodontal disease, it seems that the use of IR LED light could be the best option in Dentistry.

Expression and degranulation of mast cells in laser photobiomodulated mucositis chemo-induced: pilot study in hamsters

This study aimed to evaluate the influence of laser photobiomodulation on the expression and degranulation of mast cells in chemo-induced oral mucositis (OM) lesions in hamsters. Twelve adult male Syrian hamsters (Mesocricetus auratus), golden lineage, were submitted to OM induction. They were divided into three groups: control-OM without treatment (C), OM treated with red laser (RL), OM treated with infrared laser (IL) and analyzed in the experimental time of 7 days. Three and 4 days after the intraperitoneal injection of the chemotherapy drug fluorouracil, the OM lesions were induced by making grooves in the right cheek pouch. Immediately after chemoinduction, the hamsters were submitted to photobiomodulation every 48 h for 7 days. The specimens were processed and stained using the hematoxylin-eosin and toluidine blue techniques. There was a predominance of mild chronic inflammation in the experimental groups and a greater persistence of neutrophils in the control group (C), although not statistically significant. The group irradiated with red laser (RL) had the highest mean mast cell expression (38.28 ± 19.05) (p < 0.001). As for the degranulation activity in mast cells, the control group (C) showed a greater number of fields with more than 50% of degranulated cells, presenting statistical significance when comparing it with the RL (p < 0.009) and IL (p = 0.036) group. It can be concluded that photobiomodulation, at both wavelengths, decreased mast cell degranulation, accelerating the inflammatory process. The use of infrared laser provided, in addition to less degranulation, the quantitative reduction of mast cells.

Immunomodulation—What to Modulate and Why? Potential Immune Targets

Despite over 50 years of research into the immunology of periodontal disease, the precise mechanisms and the role of many cell types remains an enigma. Progress has been limited by the inability to determine disease activity clinically. Understanding the immunopathogenesis of periodontal disease however is fundamental if immunomodulation is to be used as a therapeutic strategy. It is important for the clinician to understand what could be modulated and why. In this context, potential targets include different immune cell populations and their subsets, as well as various cytokines. The aim of this review is to examine the role of the principal immune cell populations and their cytokines in the pathogenesis of periodontal disease and their potential as possible therapeutic targets.

Cytokine profiles and the dynamic of gingivitis development in humans

AIM

To investigate the relationship between cytokine profiles and "fast" and "slow" patterns of gingival inflammation development.

MATERIALS AND METHODS

Forty-two adults participated in an experimental gingivitis study, comprising a 2-week hygiene phase (clinical examination and professional cleaning); a 3-week induction phase (absence of oral hygiene); and a 2-week resolution phase (re-establishment of oral hygiene). Plaque and gingival inflammation scores were assessed. Interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and tumour necrosis factor-alpha (TNF-α) from gingival crevicular fluid were collected and measured by multiplex ELISA. Group-based-trajectory-modelling (GBTM) was used to model cytokine profiles over the induction phase. The effect of gingival inflammation on cytokine levels over time was estimated with mixed-effects modelling.

RESULTS

GBTM analysis revealed two cytokine profiles, "non-organized response" (IL-4, IL-6, IL-8, IL-12, and IL-13) and "organized response" (IL-2, IL-10, and TNF-α). Among the "slow" responders, neither cytokine profile was associated with gingivitis. In contrast, a "fast" response was associated with a higher "non-organized response" factor (coef. 0.14) and a lower "organized response" factor (coef. -0.03).

CONCLUSION

A "fast" gingivitis development was associated with a higher "non-organized response" and a lower "organized response", which may elucidate the role of individual variability in gingivitis susceptibility.

Oral lichen planus: a microbiologist point of view

Oral lichen planus (OLP) is a chronic disease of uncertain etiology, although it is generally considered as an immune-mediated disease that affects the mucous membranes and even the skin and nails. Over the years, this disease was attributed to a variety of causes, including different types of microorganisms. This review analyzes the present state of the art of the disease, from a microbiological point of view, while considering whether or not the possibility of a microbial origin for the disease can be supported. From the evidence presented here, OLP should be considered an immunological disease, as it was initially proposed, as opposed to an illness of microbiological origin. The different microorganisms so far described as putative disease-causing agents do not fulfill Koch’s postulates; they are, actually, not the cause, but a result of the disease that provides the right circumstances for microbial colonization. This means that, at this stage, and unless new data becomes available, no microorganism can be envisaged as the causative agent of lichen planus.

Quantification and distribution of mast cells in oral periapical inflammatory lesions

Background:

Periapical granuloma and periapical cysts develop as a sequela of inflammation of dental pulp, usually a consequence of an infected root canal. Mast cells (MCs) have most frequently been implicated in the pathophysiology of periapical lesions such as periapical granulomas and cysts.

Aims:

The present study was undertaken to emphasize the presence and quantification of MCs in periapical lesions (granulomas and cysts) using toluidine blue stain, with an aim to elucidate their role in the pathogenesis of these lesions.

Materials and Methods:

The study comprised a total of 55 previously diagnosed cases (30 cases of radicular cyst and 25 cases of periapical granuloma) selected from the departmental archives. The MCs were quantified in all the sections in the three zones, namely the epithelial, subepithelial, and deeper connective tissue zones. The results were sent for statistical analysis.

Statistical Analysis:

Wilcoxon paired t-test and Mann–Whitney U test were applied for intra- and intergroup comparison MCs in different zones of periapical granulomas and radicular cyst, respectively.

Results:

A statistically significant difference was observed between the two lesions in all the three zones, i.e., epithelial, subepithelial, and in deeper connective tissue zone with P = 0.001.

Conclusion:

Although MCs were present in all the three zones of both periapical cysts and granuloma, they were predominantly observed in radicular cysts than in periapical granuloma. This suggests a significant role of MC in initiation, development, and progression of these periapical lesions.

Mast cell expression in oral lichen planus: A systematic review

Lichen planus is a common chronic, inflammatory, immune-mediated mucocutaneous disorder affecting the skin and mucosa. The role of mast cells in the genesis of lichen planus has been debated. Establishing a definitive part played by mast cells and its degranulation would possibly provide a permanent, cost-effective treatment modality for oral lichen planus (OLP). This review aims to study the expression of mast cells qualitatively and quantitatively in OLP. The research questions were framed to assess the mast cell count, localization within the epithelium basement membrane zone and degranulation of mast cells. We performed a systematic search of PubMed, Medline, Cochrane and Web of Science. We found a total of 120 studies from which 12 were found suitable for the review. There is a marked increase in the number of mast cells in OLP. The mast cells were seen in increased numbers in the epithelial and connective tissue junction at areas of basement membrane disruption. There was also an increase in the degranulation of mast cells. It is evident that there is an increase in the mast cell number in lichen planus and its subsequent degranulation.

Quantitative and Qualitative Analysis of Mast Cells in Oral Lichen Planus and Its Effect on Basement Membrane Using Special Stains

Background:

Oral lichen planus (OLP) is characterized histologically by epithelial basal cell destruction and a dense subepithelial lymphocytic infiltrate. Mast cells (MCs) play a role in the pathogenesis and progression of the disease causing changes in the basement membrane (BM). BM is seen as continuous or fragmented, distinct or indistinct, and afibrillar or fibrillar extensions.

Aims and Objectives:

This study was done to demonstrate the BM using acriflavine stain in addition to hematoxylin and eosin (H-E) stain. An attempt was also made to study MC using Azure A stain and assess the degree of changes in the thickness of BM associated with degranulated MC in patients with OLP.

Materials and Methods:

A total of 66 paraffin-embedded tissue sections which included 30 inflamed gingival mucosa (IGM) and 36 OLP were stained with H-E stain, Azure A, and fluorescent periodic acid–acriflavine stain.

Results:

MC density was higher in OLP when compared with MC in IGM. Degranulated MCs were found in abundance in OLP. Thickness of BM was significantly less in OLP when compared with IGM. Significant fragmentation was seen in OLP when compared with BM of IGM.

Conclusion:

Degranulated MC in OLP may or may not alter the quality of BM but definitely seems to influence the thickness of the BM both directly and indirectly.

Role of mast cells in inflammatory and reactive pathologies of pulp, periapical area and periodontium

Mast cells (MCs) have been discovered over 130 years ago; their function was almost exclusively linked to allergic affections. At the time being, it is well known that MCs possess a great variety of roles, in both physiologic and pathologic conditions. In the oral tissues, MCs release different pro-inflammatory cytokines and tumor necrosis factor-alpha that promote leukocyte infiltration in various inflammatory states of the oral cavity. These cells play a key role in the inflammatory process and, as a consequence, their number changes in different pathologic conditions of the oral cavity, such as gingivitis and periodontitis. By understanding the role of MCs in the pathogenesis of different inflammatory diseases of the oral cavity, these cells may become therapeutic targets that could possibly improve the prognosis. Therefore, this review summarizes the current understanding of the role of MCs in various inflammatory pulpal, periapical and periodontal pathophysiological conditions.

Antimicrobial agent triclosan disrupts mitochondrial structure, revealed by super-resolution microscopy, and inhibits mast cell signaling via calcium modulation

The antimicrobial agent triclosan (TCS) is used in products such as toothpaste and surgical soaps and is readily absorbed into oral mucosa and human skin. These and many other tissues contain mast cells, which are involved in numerous physiologies and diseases. Mast cells release chemical mediators through a process termed degranulation, which is inhibited by TCS. Investigation into the underlying mechanisms led to the finding that TCS is a mitochondrial uncoupler at non-cytotoxic, low-micromolar doses in several cell types and live zebrafish. Our aim was to determine the mechanisms underlying TCS disruption of mitochondrial function and of mast cell signaling. We combined super-resolution (fluorescence photoactivation localization) microscopy and multiple fluorescence-based assays to detail triclosan's effects in living mast cells, fibroblasts, and primary human keratinocytes. TCS disrupts mitochondrial nanostructure, causing mitochondria to undergo fission and to form a toroidal, "donut" shape. TCS increases reactive oxygen species production, decreases mitochondrial membrane potential, and disrupts ER and mitochondrial Ca²⁺ levels, processes that cause mitochondrial fission. TCS is 60 × more potent than the banned uncoupler 2,4-dinitrophenol. TCS inhibits mast cell degranulation by decreasing mitochondrial membrane potential, disrupting microtubule polymerization, and inhibiting mitochondrial translocation, which reduces Ca²⁺ influx into the cell. Our findings provide mechanisms for both triclosan's inhibition of mast cell signaling and its universal disruption of mitochondria. These mechanisms provide partial explanations for triclosan's adverse effects on human reproduction, immunology, and development. This study is the first to utilize super-resolution microscopy in the field of toxicology.

Association Between Mast Cells and Collagen Maturation in Chronic Periodontitis in Humans

Mast cells (MCs) can influence the maturation of collagen fibers. This study evaluated the relationship between the distribution and degranulation of MCs and collagen maturation in human gingival tissue in chronic periodontitis. A total of 16 specimens of patients clinically diagnosed as periodontitis and 18 controls clinically diagnosed as healthy or gingivitis were included. Immunohistochemistry and Picrosirius staining were performed to identify MCs and assess collagen fibers, respectively. Chi-square, t test, and Pearson's correlation test ( p<0.05) were used. In control specimens, there was a positive association between MCs in the connective tissue and the presence of immature collagen ( p=0.001); in periodontitis samples, this association was not confirmed ( p≥0.12). There was no significant relationship between periodontal diagnosis and collagen maturation or MC degranulation ( p≥0.35). MC density was significantly higher ( p=0.04) in periodontitis tissue (339.01 ± 188.94 MCs/mm²) than in control tissue (211.14 ± 131.13 MCs/mm²) in the area of connective tissue containing inflammatory infiltrate. There was a correlation between the number of MCs and probing depth ( r = 0.34, p=0.04). MCs are involved in the pathogenesis of periodontal diseases and might be associated with collagen maturation in periodontal tissue during the early stages of periodontal disease pathogenesis.

Role of Mast Cells in Oral Lichen Planus and Oral Lichenoid Reactions

Introduction

Oral lichen planus (OLP) is a chronic T cell mediated disease of oral mucosa, skin, and its appendages with a prevalence of 0.5 to 2.6% worldwide. Oral lichenoid reactions (OLR) are a group of lesions with diverse aetiologies but have clinical and histological features similar to OLP, thereby posing a great challenge in differentiating both lesions. Mast cells are multifunctional immune cells that play a major role in the pathogenesis of lichen planus by release of certain chemical mediators. Increased mast cell densities with significant percentage of degranulation have been observed as a consistent finding in pathogenesis of oral lichen planus.

Aim

The current study was aimed at quantifying the mast cells in histopathological sections of OLP and OLR thereby aiding a means of distinguishing these lesions.

Materials and Methods

The study group involved 21 cases of oral lichen planus, 21 cases of oral lichenoid reactions, and 10 control specimens of normal buccal mucosa. All the cases were stained with Toluidine Blue and routine haematoxylin and eosin and the mast cells were quantified.

Statistical Analysis Used

The results were analyzed using the Kruskal–Wallis test and an intergroup analysis was performed using Mann–Whitney U test.

Conclusion

The number of mast cells showed an increased value in oral lichen planus when compared to oral lichenoid reaction and thus an estimation of mast cells count could aid in distinguishing OLP from OLR histopathologically.

Evaluation of mast cells in oral premalignant and malignant lesions: A histochemical study

Introduction:

Oral leukoplakia, oral submucous fibrosis, and oral lichen planus are the precancerous or potentially malignant lesions and conditions whereas oral squamous cell carcinoma (OSCC) is a cancerous or malignant lesion of the oral cavity. They have characteristic clinical and histopathological features. These diseases not only originate from epithelium but also associated with chronic inflammation juxta-epithellialy. Mast cells present in the connective tissue stroma and release pro-inflammatory and mitogenic cytokines. These functions of mast cells contribute and enhance the pathogenesis translation of diseases.

Aim:

The study was done to histologically evaluate the number of mast cells in oral epithelial dysplasia and OSCC and compare it with normal oral mucosa (NOM).

Materials and Methods:

Forty-five cases each of oral dysplasia, OSCC and ten cases of NOM were studied for mast cell number using toluidine blue.

Results:

There was a highly significant increase of mast cells in oral epithelial dysplasia on comparison with OSCC whereas there was only a significant increase in mast cells in OSCC on comparison with NOM.

Conclusion:

The literature has proven that mast cells can be an indicator of increased angiogenesis and hence can help in the prediction of carcinogenesis, its progression, and also the prognosis of the malignant lesions.

Mast Cells: Key Players in the Shadow in Oral Inflammation and in Squamous Cell Carcinoma of the Oral Cavity

Although mast cells (MCs) have been discovered over 130 years ago, their function was almost exclusively linked to allergic affections. At the time being, it is well known that MCs possess a great variety of roles, in both physiologic and pathologic conditions. In the oral tissues, MCs release different proinflammatory cytokines, tumor necrosis factor alpha (TNF-α), that promote leukocyte infiltration in various inflammatory states of the oral cavity. These cells play a key role in the inflammatory process and, as a consequence, their number changes in different pathologic conditions of the oral cavity, like gingivitis, periodontitis, and so on. MCs also represent a rich source of proteases, especially of mast cell tryptase and chymase, which directly degrade the extracellular matrix through their proteolytic activity and thus indirectly stimulate angiogenesis and facilitate invasion and metastasis. It may be stated that mast cells could have an impact on primary tumor development, progression, and metastases in oral squamous cell carcinoma. By understanding the role of mast cells in the pathogenesis of different inflammatory and tumor diseases of the oral cavity, these cells may become therapeutic targets that could possibly improve the prognosis and survival of these patients.

Incidence of Mast Cells in Gingival and Periapical Inflammation- A Kaleidoscopic Study

INTRODUCTION

Mast cells are large granular cells that have classically been related to neutrophil stimulation during early step of inflammation.

AIM

The objective of this work was to identify the incidence of mast cells in inflammatory lesions like periapical granuloma, pyogenic granuloma, gingival hyperplasia. 1. To assess the staining intensity of mast cells by using different metachromatic stains. 2. To correlate the above findings histopathologically.

MATERIALS AND METHODS

In this study, we used 5 micron thick sections from paraffin-embedded tissue blocks of previously diagnosed periapical and gingival inflammatory lesions. The sections were stained with routine H & E and metachromatic stains like Toluidine blue, Alcian blue, Aldehyde fuchsin and Giemsa. The number of mast cells was quantified. Statistical analysis was done and mast cell numbers were compared.

RESULTS

In both gingival and periapical inflammatory lesions, toludine blue showed more number of mast cells followed by giemsa. Giemsa stain showed statistical significance in differentiating both periapical and gingival lesions (p<0.05) in terms of mast cell count. Moderate inflammation (46.4%) was seen in a higher propotion of gingival inflammations whereas periapical inflammatory lesions revealed severe inflammation (53.3%). In both types of inflammatory lesions, higher staining intensity was shown by toludine blue followed by giemsa which was statistically significant.

CONCLUSION

Mast cell number is inversely proportional to inflammatory response in gingival inflammatory lesions and directly proportional to inflammatory response in periapical inflammatory lesions. Although, toludine blue is found to be a better stain, giemsa has equivalent properties as that of toludine blue.

Antimicrobial agent triclosan is a proton ionophore uncoupler of mitochondria in living rat and human mast cells and in primary human keratinocytes

Triclosan (TCS) is an antimicrobial used widely in hospitals and personal care products, at ~10 mm. Human skin efficiently absorbs TCS. Mast cells are ubiquitous key players both in physiological processes and in disease, including asthma, cancer and autism. We previously showed that non-cytotoxic levels of TCS inhibit degranulation, the release of histamine and other mediators, from rat basophilic leukemia mast cells (RBL-2H3), and in this study, we replicate this finding in human mast cells (HMC-1.2). Our investigation into the molecular mechanisms underlying this effect led to the discovery that TCS disrupts adenosine triphosphate (ATP) production in RBL-2H3 cells in glucose-free, galactose-containing media (95% confidence interval EC50 = 7.5-9.7 µm), without causing cytotoxicity. Using these same glucose-free conditions, 15 µm TCS dampens RBL-2H3 degranulation by 40%. The same ATP disruption was found with human HMC-1.2 cells (EC50 4.2-13.7 µm), NIH-3 T3 mouse fibroblasts (EC50 4.8-7.4 µm) and primary human keratinocytes (EC50 3.0-4.1 µm) all with no cytotoxicity. TCS increases oxygen consumption rate in RBL-2H3 cells. Known mitochondrial uncouplers (e.g., carbonyl cyanide 3-chlorophenylhydrazone) previously were found to inhibit mast cell function. TCS-methyl, which has a methyl group in place of the TCS ionizable proton, affects neither degranulation nor ATP production at non-cytotoxic doses. Thus, the effects of TCS on mast cell function are due to its proton ionophore structure. In addition, 5 µm TCS inhibits thapsigargin-stimulated degranulation of RBL-2H3 cells: further evidence that TCS disrupts mast cell signaling. Our data indicate that TCS is a mitochondrial uncoupler, and TCS may affect numerous cell types and functions via this mechanism. Copyright © 2015 John Wiley & Sons, Ltd.

Correlation of mast cells in different stages of human periodontal diseases: Pilot study

AIMS AND OBJECTIVES

The aim of this study was to evaluate and correlate the relationship between mast cells counts and different stages of human periodontal diseases.

MATERIALS AND METHODS

The study sample comprised 50 patients, which were divided into three groups, consisting of 10 cases of clinically healthy gingival tissues (control group) 20 cases of dental plaque-induced gingivitis with no attachment loss and 20 cases of localized chronic periodontitis (LCP) characterized by the loss of periodontal support. The samples for control group were obtained during tooth extractions for orthodontic reasons. The specimens were immediately fixed in 10% neutral buffered formalin.

CONCLUSION

In this study, LCP cases had higher mast cell counts compared to gingivitis sites or healthy tissues. Increased mast cell counts in the progressing sites of periodontal diseases may indicate the importance of these cells in the progression of chronic periodontitis.

Mast Cells Contribute to Porphyromonas gingivalis-induced Bone Loss

Periodontitis is a chronic inflammatory and bone-destructive disease. Development of periodontitis is associated with dysbiosis of the microbial community, which may be caused by periodontal bacteria, such as Porphyromonas gingivalis Mast cells are sentinels at mucosal surfaces and are a potent source of inflammatory mediators, including tumor necrosis factors (TNF), although their role in the pathogenesis of periodontitis remains to be elucidated. This study sought to determine the contribution of mast cells to local bone destruction following oral infection with P. gingivalis Mast cell-deficient mice (Kit(W-sh/W-sh)) were protected from P. gingivalis-induced alveolar bone loss, with a reduction in anti-P. gingivalis serum antibody titers compared with wild-type infected controls. Furthermore, mast cell-deficient mice had reduced expression of Tnf, Il6, and Il1b mRNA in gingival tissues compared with wild-type mice. Mast cell-engrafted Kit(W-sh/W-sh) mice infected with P. gingivalis demonstrated alveolar bone loss and serum anti-P. gingivalis antibody titers equivalent to wild-type infected mice. The expression of Tnf mRNA in gingival tissues of Kit(W-sh/W-sh) mice was elevated following the engraftment of mast cells, indicating that mast cells contributed to the Tnf transcript in gingival tissues. In vitro, mast cells degranulated and released significant TNF in response to oral bacteria, and neutralizing TNF in vivo abrogated alveolar bone loss following P. gingivalis infection. These data indicate that mast cells and TNF contribute to the immunopathogenesis of periodontitis and may offer therapeutic targets.

Mast cells and oral pathologies: A Review

Mast cells (MCs) are resident cells of several types of tissues and contain many granules rich in histamine and heparin. They are distributed preferentially about the micro-vascular endothelial cells in the oral mucosa. These cells play a key role in the inflammatory process and thus their number has been found to be altered in various oral pathological conditions such as oral pyogenic granuloma, oral lichen planus, leukoplakia, oral squamous cell carcinoma, periapical cysts etc. The present review article is aimed to describe the alteration in the number of MCs along with their probable roles in these pathological conditions.

Comparison of Mast Cells and Inflammatory Cells within Periapical Lesions and Comparison of Degranulated Mast Cells Between Fibrous and Inflamed Area in Radicular Cysts: An Immunohistochemical Study

OBJECTIVE

The role of mast cells as the key effector of allergic inflammation, anaphylactic inflammatory reactions and in the pathogenesis of chronic inflammation, is well-known. The present study is adopted to compare mast cells and inflammatory cells within periapical granuloma and cysts and localize the mast cells and quantify their number in the periapical cysts so as to propose a role of mast cells in the pathogenesis of this lesion.

MATERIALS AND METHODS

Biopsy specimens of 30 periapical lesions were stained with hematoxylin-eosin, and immunohistochemical Mast Cell Tryptase from Bio SB (IHC detection system kit) antibody. The tryptase positive mast cells and mononuclear inflammatory cells were counted in 10 consecutive high power fields (100X) using the binocular microscope from Motic attached to a computer with Motic Advanced Images 3.2 software.

RESULTS

Comparative microscopic analysis indicated that periapical cyst shows more percentage of mast cells and less percentage of inflammatory cell than periapical granuloma (comparison of mean and standard deviation of total number of mast cells and inflammatory cells, mast cells 3.15±1.39 in the granuloma group and 4.43±1.91in the cyst group, inflammatory cells, 67.11±1.2 in the granuloma group and 52.66±0.8 in the cyst group). Numerous degranulated mast cells were observed in the fibrous wall than the inflammatory infiltrate of the periapical cysts. The mean and standard deviation of degranulated mast cells between the inflammatory and fibrous zone within the cyst group, being 0.95±1.10 and1.68±1.34 respectively. The values varied significantly between the two zones.

CONCLUSION

The number of inflammatory cells in the cyst group is less than periapical granuloma and total number of mast cells in the cyst group is more as compared to periapical granuloma. The degranulated cells were quantified and they were higher in the fibrous area of the cysts than the inflammatory zone. This study could support the fact that the various mediators released on degranulation play a role in the connective tissue remodeling, chronicity and expansion of the periapical lesion.

A study on assessment of mast cells in oral squamous cell carcinoma

Background:

Apart from the role of mast cells in maintenance of homeostasis and inflammation, their association with tumors has been described recently. In several malignancies, mast cell density has been found to correlate with angiogenesis, increased risk of metastasis and poor prognosis.

Aim:

The aim of the following study is to compare the number, topography and distribution of mast cells between normal oral mucosa and oral oral squamous cell carcinoma (SCC) and study the significance of mast cells in development of oral SCC.

Subjects and Methods:

A prospective case-control study including 100 patients was conducted after obtaining informed consent and ethical committee clearance. Forty cases were normal controls and 60 cases had oral SCC. Biopsy was performed and both qualitative and quantitative study of mast cells was done. Statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) 17.0 version (SPSS Inc., Chicago, IL, USA).

Results:

Buccal/labial mucosa was the most common site of lesion in SCC. Total mast cells count was a higher in SCC when compared with controls, which was a statistically significant (P < 0.001). SCC had significantly (P < 0.001) higher levels of degranulated mast cell.

Conclusion:

Role of mast cells in tumors may have direct clinical relevance and consequently, important clinical implications. Mast cells serves as a novel therapeutic target for cancer treatment and that inhibiting mast cell function may inhibit tumor growth.

Altered immunohistochemical expression of mast cell tryptase and chymase in the pathogenesis of oral submucous fibrosis and malignant transformation of the overlying epithelium

Mast cells (MCs) expressing serine proteases; tryptase and chymase, are associated with fibrosis in various diseases. However, little is known about their involvement in oral submucous fibrosis (OSF). Our goal was to evaluate the role of MC tryptase and chymase in the pathogenesis of OSF and its malignant transformation. Immunohistochemical expression of MC tryptase and chymase was evaluated in 20 cases of OSF, 10 cases of oral squamous cell carcinoma (OSCC) and 10 cases of healthy controls. Subepithelial zone of Stage 1 and 2 while deep zone of Stage 3 and 4 OSF demonstrated increased tryptase positive MCs. OSCC revealed a proportionate increase in tryptase and chymase positive MCs irrespective of areas of distribution. An altered balance in the subepithelial and deep distribution of tryptase and chymase positive MCs play an important role in the pathogenesis of OSF and its malignant transformation.

A quantitative analysis of mast cells in inflammatory periapical and gingival lesions

AIM

The aim of the study was to quantify the presence of mast cells in various inflammatory lesions like periapical granuloma, periapical cyst, inflammatory gingival hyperplasia and pyogenic granuloma. Mast cell degranulation and association with lymphocytes were also recorded in an attempt to understand the role of mast cells in the pathogenesis of these inflammatory lesions.

MATERIALS AND METHODS

The quantification of mast cells was done on toluidine blue stained sections of all the four groups of lesions, using the image analyzer software, Image-Pro-Express (Media Cybernetics, USA).

RESULTS

An increased number of mast cells in various inflammatory lesions with a significant difference between the four groups were noted. Mast cell number tended to be greater in the lesions present in the anterior region of the mouth than in the posterior region of the oral cavity. The mean mast cell number decreased with the increasing age which was directly correlated with the age of the patients. Mast cell site, distribution, degranulation and its association with fibroblasts, lymphocytes and blood vessels were noted.

CONCLUSION

The location of mast cells in different areas, their association with lymphocytes, fibroblasts, endothelial cells, and the phenomenon of degranulation helps to appreciate the release of various mediators and multiple interactions among these cells, leading to increased vascular permeability, angiogenic response, collagen synthesis, regulation of inflammation, bone resorption, and extracellular matrix destruction, thus contributing to the pathogenesis of these inflammatory lesions.

Inhibition of JNK by compound C66 prevents pathological changes of the aorta in STZ-induced diabetes

Cardiovascular diseases as leading causes of the mortality world-wide are related to diabetes. The present study was to explore the protective effect of curcumin analogue C66 on diabetes-induced pathogenic changes of aortas. Diabetes was induced in male C57BL/6 mice with a single intraperitoneal injection of streptozotocin. Diabetic mice and age-matched non-diabetic mice were randomly treated with either vehicle (Control and Diabetes), C66 (C66 and Diabetes/C66) or c-Jun N-terminal kinase (JNK) inhibitor (sp600125, JNKi and Diabetes/JNKi). All three treatments were given by gavage at 5 mg/kg every other day for 3 months. Aortic inflammation, oxidative stress, fibrosis, cell apoptosis and proliferation, Nrf2 expression and transcription were assessed by immunohistochemical staining for the protein level and real-time PCR method for mRNA level. Diabetes increased aortic wall thickness and structural derangement as well as JNK phosphorylation, all of which were attenuated by C66 treatment as JNKi did. Inhibition of JNK phosphorylation by C66 and JNKi also significantly prevented diabetes-induced increases in inflammation, oxidative and nitrative stress, apoptosis, cell proliferation and fibrosis. Furthermore, inhibition of JNK phosphorylation by C66 and JNKi significantly increased aortic Nrf2 expression and transcription function (e.g. increased expression of Nrf2-downstream genes) in normal and diabetic conditions. These results suggest that diabetes-induced pathological changes in the aorta can be protected by C66 via inhibition of JNK function, accompanied by the up-regulation of Nrf2 expression and function.

Mast cell density in oral submucous fibrosis: a possible role in pathogenesis

OBJECTIVE

Oral submucous fibrosis (OSMF) is a premalignant condition of oral cavity characterized by inflammation and progressive mucosal fibrosis. It has questionable pathogenesis. Mast cells (MC) have been associated with variety of inflammatory and fibrotic conditions, but little is known about their role in OSMF. Mast cells have been studied in normal gingiva, chronic inflammatory gingivitis, desquamative gingivitis, lichen planus, OSMF and oral cancer. Mast cells exhibit phenotypic plasticity. There is variation in the mast cell mediators with the change in the microenvironment, which makes the study of this cell in various diseases interesting.

STUDY DESIGN

A retrospective study was conducted to find possible correlation between MC in 25 cases of OSF, 10 cases of oral squamous cell carcinoma (OSCC) and 10 cases of normal buccal mucosa by means of acidified toluidine blue staining method.

RESULTS

The density of MC increased with disease progression. The densities of MC were significantly higher in OSMF than in normal buccal mucosa (p=0.001). The average numbers of MCs per square millimeter were 25, 49.50, 53.25 & 55.25 respectively.

CONCLUSION

The results suggest that MC have a definite role in initiation and progression of OSMF.

Correlation of mast cells in periodontal diseases

Background:

Among the cells involved in immune and inflammatory responses in periodontal disease, mast cells have been shown to be capable of generating a large number of biologically active substances. Mast cells are mobile, bone-marrow-derived, granule-containing immune cells that are found in all connective tissue and mucosal environments and in the peripheral and central nervous systems. Mast cells are able to phagocytose, process and present antigens as effectively as macrophages. The present study was undertaken to quantify the mast cells in health and disease, whether they correlate degree of inflammation and clinical features of periodontium.

Materials and Methods:

Ten cases of localized chronic periodontitis (CP), 10 cases of dental plaque-induced gingivitis (DPIG) and 10 cases of clinically healthy gingival tissues were selected. Samples were obtained from patients undergoing for periodontal surgery in CP and DPIG. In health group third molar impacted and covered with operculum without any inflammation were selected. Sample fixed in 10% buffered formalin and stained with Toludine blue stain and observed under binocular microscope.

Conclusion:

In human periodontal disease there is an increase in the number of mast cells that may be participating either in the destructive events or in the defense mechanism of periodontal disease via secretion of cytokines.

Triology of nitric oxide, mast cell and stress in pathogenesis of oral lichen planus

INTRODUCTION

Oral Lichen planus (OLP) is chronic, autoimmune, mucocutaneous disease. Numerous etiological factors have been proposed, but an authoritative and exact source of the disease has not been brought forward. Reactive nitrogen species (RNS), mast cell (MC) and stress are considered to play a key role in inflammation-mediated carcinogenesis generating nitric oxide (NO).

AIM

To evaluate the salivary NO levels, mast cells and stress levels and to correlate them in pathogenesis of OLP.

MATERIALS AND METHODS

The study was conducted using saliva samples of patients. The study consisted of two groups: Group-I constituted the subjects with OLP group (n=25) and group II comprised the control group (n=25). The saliva of the patients was evaluated using Griess Reagent and Spectrophotometer, MC count done by using special stains, and stress levels measured using DASS Scale.

RESULTS

The difference between the means was found to be highly significant (P < 0.05). The intergroup comparison of optical density (OD) values, a mast cell count and stress level was found to be highly significant.

CONCLUSION

Salivary NO, increase in mast cell count and stress has a definitive role in OLP pathogenesis.

Role of mast cells in pathogenesis of oral lichen planus

Recent attention has been directed toward the role of mast cells in the pathogenesis of oral lichen planus. Mast cells are responsible for trafficking inflammatory cells into the connective tissue that in turn helps in progression and maintenance of chronicity of oral lichen planus (OLP). OLP is a T-cell-mediated chronic inflammatory oral mucosal disease of unknown etiology, and lesions contain few B-cells or plasma cells and minimal deposits of immunoglobulin or complement. Hence, OLP is ideally positioned for the study of human T-cell-mediated inflammation and autoimmunity. This study was done to evaluate the mast cell count using toluidine blue stain in OLP and compares it with oral lichenoid reaction (OLR), and to propose the possible role of mast cells in the pathogenesis of OLP and OLR. Ten cases each of OLP and OLR and five cases of normal buccal mucosa were taken from the archives of Department of Oral Pathology. The samples were stained with toluidine blue using standard toluidine blue method by Wolman 1971. An increase in mast cell count was observed in OLP and OLR in comparison to normal oral mucosa. However, no significant differences in mast cell count were noted between OLP and OLR.

Degranulated mast cells and TNF-α in oral lichen planus and oral lichenoid reactions diseases

Background:

The objective of this study was to assess mast cells and TNF-α in oral lichen planus (OLP) and oral lichenoid reactions (OLR) patients as diagnostic marker to the differential diagnosis of OLP and OLR diseases.

Materials and Methods:

In this cross-sectional study, samples were obtained from 30 OLP and 30 OLR patients, between June 2010 and March 2011 in Dental clinic of the University of Isfahan, Iran. Mast cells in the reticular layer of the lamina propria for samples were evaluated using toluidine blue method and immunohistochemical technique. The clinical relevant data taken into account were: demographical data, total number and degranulated mast cells, ratio of degranulated mast cells and TNF-α positive degranulated mast cells.

Results:

In OLP and OLR, the total mast cells were 21.2 ± 7.9 and 20.3 ± 6.8, degranulated mast cells were 15.5 ± 6.9 and 19.2 ± 6.9, ratio of degranulated mast cells to total mast cells were 0.716 ± 0.067 and 0.946 ± 0.081, and TNF-α positive degranulated mast cells were 13.6 ± 6.3 and 17.1 ± 6.04, respectively. There was no significant difference for the total mast cells. But degranulated mast cells, ratio of degranulated mast cells and TNF-α positive degranulated mast cells in OLR were significantly higher than OLP patients.

Conclusions:

Our results showed that the degranulated mast cells, ratio of degranulated mast cells and TNF-α in OLR was significantly more than OLP patients and these may be able to be used as diagnostic markers to the differential diagnosis of OLP and OLR.

Mast cells in human odontogenic cysts

Mast cells are granule-containing cells in mucosal and connective tissues that are known to play a central role in allergic and inflammatory responses owing to pro-inflammatory mediators. Cysts in jaws are among the most common expansive, benign and destructive bone lesions; at some stage they are associated with chronic inflammation. Earlier studies have identified mast cells in odontogenic cysts (OC). We investigated the presence and distribution of mast cells and compared their number in different types of radicular cysts (RC), dentigerous cysts (DC) and odontogenic keratocysts (OKC). Ten cases each of RC, DC and OKC diagnosed clinically and histopathologically were selected and stained with 1% toluidine blue. The greatest number of mast cells/mm(2) was found in RC. The fewest mast cells/mm(2) were found in OKC. The subepithelial zones of all cysts contained more mast cells than the deeper zones.

Characterization of inflammatory cell infiltrate in human dental pulpitis

INTRODUCTION

To evaluate the microscopic characteristics and densities (per mm(2) ) of tryptase(+) mast cells, CD4(+) T helper lymphocytes, CD45RO(+) memory T lymphocytes, foxp3(+) T regulatory lymphocytes, CD20(+) B lymphocytes, CD68(+) macrophages, and CD31(+) blood vessels in human dental pulpitis (n=38) and healthy pulpal tissue (n=6).

METHODOLOGY

The pulps of 38 human teeth with a clinical diagnosis of irreversible pulpitis were removed by pulpectomy. The pulp tissue was immersed in 10% buffered formalin for evaluation using light microscopy. Tryptase, CD4, CD45RO, foxp3, CD20, CD68, and CD31 expressions were analysed using immunohistochemistry; other microscopic features, such as intensity of inflammatory infiltrate and collagen deposition, were evaluated using haematoxylin and eosin stain. Wilcoxon and Mann-Whitney tests were used for statistical analysis. The significance level was set at α=5%.

RESULTS

Two microscopic patterns of pulpitis were found: group 1 (G1) (n=15) had an intense inflammatory infiltrate and mild collagen deposition; conversely, group 2 (G2) (n=23) had a scarce inflammatory infiltrate and intense collagen deposition. The numbers of CD68(+) macrophages (P=0.004) and CD20(+) B (P=0.068) lymphocytes and the density of blood vessels (P=0.002) were higher in G1 than in G2. However, a similar number of CD4(+) and CD45RO(+) T lymphocytes was found in both groups (P>0.05). When present, tryptase(+) mast cells were equally distributed in G1 and G2, whereas foxp3(+) T regulatory lymphocytes were detected in 59% and 14% of the samples of G1 and G2. Controls exhibited lower numbers of foxp3, tryptase, CD4, CD45RO, CD68 and CD20 positive cells than G1 and G2.

CONCLUSIONS

Irreversible pulpitis had distinct microscopic features with important quantitative and qualitative differences in inflammatory cell infiltration.

Stem cell factor in gingival crevicular fluid in periodontal health and disease

Background: Stem cell factor is a pleiotropic cytokine produced by several cell types including fibroblasts, bone marrow stromal cells, mast cells, and endothelial cells. In addition, stem cell factor is an important hematopoietic growth factor, which binds to and activates the ligand for the tyrosine kinase-type receptor c-kit. Objectives: Analyze concentration of stem cell factor within gingival crevicular fluid (GCF) in both periodontal health and disease and to determine the correlation of stem cell factor in GCF and inflammatory status of periodontal tissues. Materials and methods: Forty-five subjects (aged 24 to 75 years) were classified into the following three groups according to their periodontal tissue status as group I (clinically healthy gingiva with no loss of attachment), group II (gingivitis with no attachment loss), and group III (periodontitis). GCF samples collected from each patient were examined for stem cell factor level using enzyme-linked immunosorbant assay. Results: The maximum level of stem cell factor in GCF was obtained for group III (71.8±7.8 pg/g protein), and the lowest mean stem cell factor concentration in GCF was observed for group I (22.1±7.3 pg/g protein). The GCF stem cell factor level of patients in group III was statistically higher than that in group II (p <0.04) and group I (p <0.001). In addition, the mean GCF levels of stem cell factor in group II (48.1±7.5 pg/g protein) were significantly higher than those in group I (p <0.02). There was a positive correlation between stem cell factor in GCF and gingival inflammation index (r=0.59, p <0.001) Conclusion: GCF levels of stem cell factor increased in parallel with the severity of periodontal disease. Its levels in GCF could be potentially useful as a biochemical marker of periodontal inflammation and the host response.

Light, including ultraviolet

Ultraviolet (UV) light is intricately linked to the functional status of the cutaneous immune system. In susceptible individuals, UV radiation can ignite pathogenic inflammatory pathways leading to allergy or autoimmunity. In others, this same UV radiation can be used as a phototherapy to suppress pathogenic cutaneous immune responses. These vastly different properties are a direct result of UV light's ability to ionize molecules in the skin and thereby chemically alter them. Sometimes these UV-induced chemical reactions are essential, the formation of pre-vitamin D(3) from 7-dehydrocholesterol, for example. In other instances they can be potentially detrimental. UV radiation can ionize a cell's DNA causing adjacent pyrimidine bases to chemically bond to each other. To prevent malignant transformation, a cell may respond to this UV-induced DNA damage by undergoing apoptosis. Although this pathway prevents skin cancer it also has the potential of inducing or exacerbating autoreactive immune responses by exposing the cell's nuclear antigens. Ultraviolet-induced chemical reactions can activate the immune system by a variety of other mechanisms as well. In response to UV irradiation keratinocytes secrete cytokines and chemokines, which activate and recruit leukocytes to the skin. In some individuals UV-induced chemical reactions can synthesize novel antigens resulting in a photoallergy. Alternatively, photosensitizing molecules can damage cells by initiating sunburn-like phototoxic reactions. Herein we review all types of UV-induced skin reactions, especially those involving the immune system.

Presence and quantification of mast cells in the gingiva of cats with tooth resorption, periodontitis and chronic stomatitis

OBJECTIVE

Mast cells are tissue-dwelling granule-containing immune cells that play a pivotal role in the pathogenesis of inflammation and other processes. The three most common orodental disorders in cats are periodontitis, feline resorptive lesions (FRL), and chronic gingivostomatitis (FCGS). The presence and density of mast cells in the gingiva has been established in healthy cats but not in cats affected by FRL, FCGS or periodontitis. The aim of the present study was to document and quantify the presence of mast cells in the gingiva adjacent to teeth affected by FRL, FCGS or chronic periodontitis.

METHODS

Samples from the gingiva of 32 cats affected by FRL, FCGS or periodontitis were obtained and compared to samples obtained from 7 specific pathogen-free (SPF) cats. Evaluation of mast cells and the inflammatory infiltrate were performed on hematoxylin and eosin, and toluidine blue stained sections.

RESULTS

Mast cells densities were significantly increased in gingival tissues adjacent to teeth affected by FRL, FCGS or periodontitis in comparison to SPF samples. There were no significant differences between gingival tissues of the FRL, FCGS and periodontitis groups. However, the relative inflammatory score in the FRL group was significantly lower as compared to the FCGS or periodontitis groups, yet with similar density of mast cells.

CONCLUSION

In the gingiva of cats affected with FRL, FCGS or periodontitis, there is an increase in the number of mast cells. The high number of mast cells in the FRL group and concurrent mild inflammatory reaction suggests the notion that mast cells may potentially play role in the pathogenesis of FRL.

Effect of a mucoadhesive gel and dental scaling on gingivitis in dogs

Twenty client-owned dogs diagnosed with gingivitis were studied over a 45-day period in order to investigate the effect of professional dental prophylaxis combined with the use of a topical mucoadhesive gel containing adelmidrol, an aliamide. A non-intrusive papillary-marginal-gingival index (PMGI) was measured at each assessment, while the gingivitis index (GI) was measured only at the beginning and end of the study. Compared to the control group, the treated dogs had a significant decrease (P < 0.005) in the average GI index during the course of the study. A significant reduction (P < 0.002) in the average PMGI index was observed in both groups 15-days following dental prophylaxis. However at 30 and 45-days following dental prophylaxis, the PMGI index values were significantly different (P < 0.005) from baseline only in treated dogs. These results suggest that the combined use of a mucoadhesive gel with dental scaling was able to improve the regression of gingival inflammation and lengthen the therapeutic benefits of dental scaling and polishing during a limited study period.

Histochemical analysis of pathological alterations in oral lichen planus and oral lichenoid lesions

Lichen planus is a dermatologic disease of unknown etiology characterized by keratotic plaques on the skin. Many patients also harbor white lesions of the oral mucosa. The literature contains numerous reports of lichen planus-like lesions evolving in conjunction with the administration of a variety of pharmacologic agents. It is difficult, if not impossible, to distinguish such lesions from one another. The present study evaluated the epithelial and basement membrane thickness, mast cells (intact cells and degranulated cells subepithelially) and the presence or absence of blood vessels in oral lichen planus and oral lichenoid lesions. The evaluation was done using the periodic acid-schiff (PAS) and toluidine blue staining techniques on 20 cases each of oral lichen planus and oral lichenoid lesions and 5 control specimens of normal buccal mucosa. The results showed an increased number of degranulated mast cells in areas of basement membrane degeneration, increased vascularity and increased PAS-positive basement membrane thickness in oral lichen planus as compared with oral lichenoid lesions. Reduced epithelial thickness was found in oral lichen planus. The present study emphasizes the importance of these parameters in differentiating oral lichen planus from oral lichenoid lesions using special staining techniques.

Mast cells and lymphocyte subsets in pulps from healthy and carious human teeth

OBJECTIVE

To evaluate the presence of cytolytic T lymphocytes (CD8+), memory T cells (CD45RO+), helper T lymphocytes (CD4+), and mast cells in pulps from healthy and carious human teeth.

STUDY DESIGN

The teeth were separated into groups: I = unerupted; II = partially erupted, without caries; III = erupted, without caries; IV = erupted with shallow dentine caries; and V = teeth with pulp polyps. The immunoperoxidase staining procedure was used to detect CD8, CD45RO, CD4, and tryptase (mast cell marker) antigens. The number of each cell type was obtained by counting the number of cells per mm2.

RESULTS

Mast cells were only present in pulp polyps. Pulps from carious teeth contained more CD4+ and CD8+ cells than from noncarious teeth. There was a significant decrease in the number of lymphocytes in pulp polyps in comparison to the other groups.

CONCLUSIONS

Mast cells probably do not contribute to the early vascular or specific immune responses in the initial dental pulp pathosis, although they may be involved in a chronic phase of pulp inflammation such as pulp polyps. On the other hand, CD4+ and CD8+ T cells participate mainly in initial phenomena of the immune response to incipient caries and seem not to substantially contribute to the response in pulp polyps.

The regulatory effect of SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1-pyrazol-1-l]benzenesulfonamide) on stem cell factor induced migration of mast cells

SC-236, (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1-pyrazol-1-]benzenesulfonamide; C(16)H(11)ClF(3)N(3)O(2)S), is a highly selective cyclooxygenase (COX)-2 inhibitor. Recently, there have been reports that SC-236 protects against cartilage damage in addition to reducing inflammation and pain in osteoarthritis. However, the mechanism involved in the inflammatory allergic reaction has not been examined. Mast cells accumulation can be related to inflammatory conditions, including allergic rhinitis, asthma, and rheumatoid arthritis. The aim of the present study is to investigate the effects of SC-236 on stem cell factor (SCF)-induced migration, morphological alteration, and cytokine production of rat peritoneal mast cells (RPMCs). We observed that SCF significantly induced the migration and morphological alteration. The ability of SCF to enhance migration and morphological alteration was abolished by treatment with SC-236. In addition, production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and vascular endothelial growth factor (VEGF) production induced by SCF was significantly inhibited by treatment with SC-236. Previous work has demonstrated that SCF-induced migration and cytokine production of mast cells require p38 MAPK activation. We also showed that SC-236 suppresses the SCF-induced p38 MAPK activation in RPMCs. These data suggest that SC-236 inhibits migration and cytokine production through suppression of p38 MAPK activation. These results provided new insight into the pharmacological actions of SC-236 and its potential therapeutic role in the treatment of inflammatory allergic diseases.

Enhancing the buccal mucosal uptake and retention of triamcinolone acetonide

In this study, the buccal mucosal uptake and retention of triamcinolone acetonide (TAC) were assessed in the presence of the skin penetration enhancer, Azone (AZ). Porcine buccal mucosa was excised, mounted in modified Ussing chambers, and pretreated with ethanolic solutions of AZ. After 2 h, the rate of TAC disappearance from the donor chamber and TAC appearance in the receptor chamber was monitored, and the mucosal retention of TAC was determined at the completion of the experiment. The permeability and mucosal uptake of TAC was also determined using the TAC-containing proprietary product, Kenalog in Orabase (KO), in the presence and absence of AZ. Pretreatment of the buccal mucosa with AZ increased the TAC disappearance permeability coefficient from 4.78+/-0.31x10(-5) cm/s to 7.12+/-0.53x10(-5) cm/s. While the TAC appearance permeability coefficient was also enhanced 3.8-fold, a 4.4-fold increase in the tissue concentration of TAC was observed. Incorporation of AZ into KO did not result in an enhanced tissue concentration of TAC, however, when the tissue was pretreated with AZ, significantly higher amounts of TAC accumulated in the tissue. Pretreatment of the buccal mucosa with AZ results in increased tissue concentrations of TAC, which may be of clinical benefit in the treatment of oral mucosal inflammatory conditions.

Quantification of mast cells in different stages of human periodontal disease

OBJECTIVE AND METHODS

Among the cells involved in immune and inflammatory responses in periodontal disease, mast cells have been shown to be capable of generating a large number of biologically active substances. The present study was undertaken to identify and quantify the presence of mast cells in different stages of human periodontal disease using histochemical (toluidine blue) and immunohistochemical (tryptase-positive mast cells) techniques.

RESULTS

Mast cell densities (cells per mm(2)) were significantly increased in chronic periodontitis/gingivitis lesions compared with clinically healthy gingival tissues (Health) uniquely by immunohistochemical technique. Interestingly, mast cells were distributed specially in close apposition to mononuclear cells.

CONCLUSIONS

In human periodontal disease there is an increase in the number of mast cells that may be participating either in the destructive events or in the defense mechanism of periodontal disease via secretion of cytokines, including perpetuation of the Th2 response, and cellular migration and healing processes.