Immunohistochemical evaluation of mast cells and vascular endothelial proliferation in oral submucous fibrosis

Linking inflammation and angiogenesis with fibrogenesis: Expression of FXIIIA, MMP-9, and VEGF in oral submucous fibrosis

OBJECTIVES

Interplay of Factor XIIIa (FXIIIa), a transglutaminase, responsible for cross-linking of matrix proteins, Matrix Metalloproteinase-9 (MMP-9), a gelatinase, and Vascular Endothelial Growth Factor (VEGF), an angiogenic inducer, were studied in relation to fibrogenesis and disease progression in oral submucous fibrosis (OSMF).

MATERIAL AND METHODS

Immunohistochemical expression of markers was studied in 60 formalin-fixed paraffin-embedded tissue blocks of OSMF and 20 normal oral mucosal tissues. FXIIIa was studied quantitatively while MMP-9 and VEGF were assessed semi-quantitatively. Expression was compared with histopathological grades of OSMF.

RESULTS

FXIIIa expression significantly increased in OSMF (p-value 0.000). However, expression decreased and cells became quiescent with increasing grades (p-value 0.000). MMP-9 (p-value epithelium 0.011, p-value connective tissue 0.000) and VEGF expression (p-value epithelium 0.000, connective tissue 0.000) increased in OSMF. A negative correlation between FXIIIa and MMP-9 (-0.653) in early grade (p-value of 0.021) and a positive correlation between FXIIIa and VEGF (0.595) (p-value of 0.032) was found in the moderate grade OSMF. Regression analysis showed a significant association (p<0.01) of FXIIIa in OSMF and with increasing grades of OSMF.

CONCLUSION

FXIIIa may play a crucial role in initiation of fibrosis in OSMF. MMP-9 may have a diverse role to play in OSMF as a regulator of fibrosis. VEGF may show an angio-fibrotic switch and contribute to fibrosis in OSMF. These cytokines may show altered function and can contribute to fibrosis and chronicity of disease due to changes in the microenvironment. Tissue stiffness in OSMF itself creates an environment that enhances the chronicity of the disease.

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

Potentiated action on the progression of OSMF by hypoxia mediated signaling pathway by the epithelial mesenchymal transition and angiogenic apparatus

Background

Epithelial-mesenchymal transition (EMT) is a complex process, in which epithelial cells acquire the characteristics of invasive mesenchymal cells. EMT has been implicated in cancer progression and metastasis as well as the formation of many tissues and organs during development.

Aim

The aim of the study was to ascertain the role of hypoxia-mediated signaling pathways influencing EMT and angiogenesis in progression of oral submucous fibrosis (OSMF).

Materials and Methods

Evaluation of the immunoexpression of alpha-smooth muscle actin (α-SMA), E-cadherin, vimentin, and factor VIII receptor antigen in OSMF and oral squamous cell carcinoma (OSCC) arising from OSMF was done. Differences between the different variables were analyzed using ANOVA test and Pearson's Chi-square test, and Mann-Whitney test was also calculated.

Results

The mean α-SMA positive myofibroblasts increased from Group 1 (OSMF) to Group 2 (OSCC), especially those in the deeper connective tissue stroma. The mean labeling index of vimentin and mean vessel density immunoexpression was more in Group 2 (OSCC) as compared to Group 1 (OSMF). Mean α-SMA correlated negatively with E-cadherin expression and positively with vimentin and factor VIII immunoexpression. E-cadherin expression correlated negatively with factor VIII and positively with Vimentin expression.

Conclusions

The molecular mechanisms responsible for the development of OSCC in patients with OSMF require unification of multiple progressive pathogenetic mechanisms involved in the progression of the disease.

Immunopathogenesis of oral submucous fibrosis by chewing the areca nut

Oral submucous fibrosis (OSF) is a chronic, progressive, scarring, and premalignant disease of the oral mucosa. Its pathogenic factors are complex and include chewing areca nuts or other spicy food items, nutrition, and genetic and immune factors. Recently, immune factors have become the focus of medical research, with increased attention being paid to the role of immune regulation in diseases, particularly tumors. OSF is accompanied by obvious changes in the immune microenvironment. The aim of this review is to discuss the potential relationship of OSF and areca nuts genetic with the immune system, including lymphocytes, macrophage, Langerhans cell, mast cell, and substances released by activated immune cells, to determine the pathogenesis and treatment of OSF from an immunologic viewpoint.

Evaluation of mast cells and burning sensation in various stages of Oral Submucous Fibrosis

Background

Oral Submucous Fibrosis (OSMF) is a potentially malignant disorder and burning sensation is the initial complaint among these patients. Scientific literature has established that mast cells play a major role in various inflammatory disorders. However, OSMF being an inflammatory disorder, the role of mast cells is yet to be established. Hence the aim of this study was to evaluate mast cells and burning sensation in various stages of Oral Submucous Fibrosis.

Methods

The study population comprised of forty subjects, thirty were clinically confirmed cases of OSMF and ten healthy individuals served as control. A complete history and clinical examination followed by an incisional biopsy was performed. Samples obtained were subjected to routine histopathological examination and mast cells evaluation.

Results

Mean number of total mast cells in Stage I, II and III OSMF were 8.5 ± 0.7, 11.31 ± 8.8 and 24.7 ± 21.2 respectively. There was a significant difference in total mast cell count between cases and controls. Degranulated mast cells was a significant predictor (p = 0.028), indicating role in clinical staging of OSMF. Degranulated mast cells had a significant role and was a positive predictor (B = 0.763, OR 2.145[95%CI 1.055-4.630]) at moderate levels of burning sensation. A significant difference (p = 0.029) in burning sensation across histopathological grades was also observed in the study.

Conclusion

Degranulated mast cells were found to have a significant influence in mild to moderate levels of burning sensation among OSMF patients. Role of degranulated mast cells were also found to be significant in various clinical stages of OSMF.

Ki67, CD105 and α-smooth muscle actin expression in disease progression model of oral submucous fibrosis

AIM

The aim of this study was to investigate the expression of Ki67, CD105 and α-smooth muscle actin (α-SMA) expression in oral submucous fibrosis (OSF) and oral squamous cell carcinoma in the background of OSF (OSCC-SMF).

METHODS

The study was carried out on paraffin-embedded tissues of 30 normal oral mucosa (NOM), 50 OSF cases and 105 OSCC-SMF. The immunohistochemistry was carried out to evaluate the expression of Ki67, CD105 and α-SMA antigen.

RESULTS

Ki67 labelling index (LI), CD105 and α-SMA expression showed increasing trend from NOM, low-risk epithelial dysplasia (LRED), high-risk epithelial dysplasia (HRED), well-differentiated squamous cell carcinoma (WDSCC), moderately differentiated squamous cell carcinoma to poorly differentiated squamous cell carcinoma. However, there was no significant difference of α-SMA expression between HRED and WDSCC. In OSCC-SMF, Ki67 LI, CD105 and α-SMA were significantly higher in advanced clinical TNM stage, metastasis and less than 3 years patient survival as compared with early clinical TNM stage, non-metastasis and 3 years or more patient survival.

CONCLUSION

Ki67 LI, α-SMA and CD105 expression alone or together correspond with the disease progression model of SMF. Hence, expression of these markers can be used as a predictive marker of clinical outcome of OSCC-SMF.

Histochemical and Immunohistochemical Analysis of Collagen Fibers and Microvascular Density in Various Grades of Oral Submucous Fibrosis

Background and Objective:

This study was aimed to evaluate the collagen fibers qualitatively and its correlation with microvascular density in various grades of oral submucous fibrosis (OSMF).

Material and Methods:

The present study comprised of total 40 cases of oral submucous fibrosis. Picrosirius red staining was done on all the specimens’ sections. They were analyzed for the colour and orientation of collagen fibers. Morphometric measurements were done using image analysis on immunohistochemical stained sections for Factor VIII-related antigen and analyzed for microvascular density.

Results:

Picrosirius red polarizing microscopy results revealed that there was a shift in the colour of collagen fibers from greenish yellow to orange red and red colour as the severity of the oral submucous fibrosis increased. The collagen fibers showed mixed orientation in early oral submucous fibrosis and parallel orientation in advanced oral submucous fibrosis. There was a significant decrease in microvascular density from early to advanced oral submucous fibrosis.

Conclusion:

The change in the colours and orientation of collagen fibers in early and advanced oral submucous fibrosis could be attributed to the fibre thickness, type of collagen, alignment and packing, cross-linking of the fibers and the section thickness. However, in advanced cases the vascularity is reduced which may predispose to epithelial atrophy and subsequent malignant changes.

Ki67, CD105, and α-SMA expression supports the transformation relevant dysplastic features in the atrophic epithelium of oral submucous fibrosis

Background

The grading of oral epithelial dysplasia is not possible in the atrophic epithelium of oral submucous fibrosis (OSMF). Recently, we found that features such as increased basal cell layer hyperplasia, abnormal superficial mitosis, increased nuclear-cytoplasmic ratio, increased nuclear size, and hyperchromasia represent transformation-relevant dysplastic features in the atrophic epithelium of OSMF. The presence of these features can be considered a high-risk feature for patients. However, these findings have not been tested and authenticated using markers relevant to oral carcinogenesis.

Method

Paraffin-embedded tissues from 30 normal oral mucosa (NOM) and 50 OSMF were retrieved from 2008 to 2016 and subjected to immunohistochemical expression using Ki67, CD105 and α-SMA antibodies.

Results

Ki67 LI showed significant increases from NOM (12.47±2.34) to LRED (23.47±3.75) to HRED (34.31±7.31) (<0.0001). Similarly, MVD was increased significantly from NOM (3.53±5.17) to LRED (27.57±12.25) to HRED (46.18±12.55) (p<0.0001). The expression of α-SMA was significantly increased from LRED (0.21±0.41) to HRED (1.13±0.56) (<0.0001). The Ki67 LI and α-SMA; MVD and α-SMA; and Ki67Ki67 LI and MVD in NOM, LRED and HRED showed a statistically significant positive correlation (P<0.0001). The increase in Ki67 LI was directly proportional to MVD and α-SMA expression from NOM to LRED to HRED (P<0.0001). The connective tissue stroma of NOM lacks α-SMA expression. Mild myofibroblast expression was noted in 4 cases of LRED (14.28%) and in 18 cases of HRED (81.81%). Moderate expression was noted only in 4 cases of HRED (22.22%).

Conclusion

Ki67 LI, CD105, and α-SMA expression showed significant differences between normal, LRED and HRED. These findings further support that features such as increased basal cell layer hyperplasia, abnormal superficial mitosis, increased nuclear-cytoplasmic ratio, and hyperchromasia could be transformation-relevant dysplastic features.

Lymph microvascularization as a prognostic indicator in neuroblastoma

Neuroblastoma is the most common extra-cranial solid pediatric cancer and causes approximately 15% of all childhood deaths from cancer. Although lymphatic vasculature is a prerequisite for the maintenance of tissue fluid balance and immunity in the body, little is known about the relationship between lymphatic vascularization and prognosis in neuroblastoma. We used our previously-published custom-designed tool to close open-outline vessels and measure the density, size and shape of all lymphatic vessels and microvascular segments in 332 primary neuroblastoma contained in tissue microarrays. The results were correlated with clinical and biological features of known prognostic value and with risk of progression to establish histological lymphatic vascular patterns associated with unfavorable histology. A high proportion of irregular intermediate lymphatic capillaries and irregular small collector vessels were present in tumors from patients with metastatic stage, undifferentiating neuroblasts and/or classified in the high risk. In addition, a higher lymphatic microvascularization density was found to be predictive of overall survival. Our findings show the crucial role of lymphatic vascularization in metastatic development and maintenance of tumor tissue homeostasis. These patterns may therefore help to indicate more accurate pre-treatment risk stratification and could provide candidate targets for novel therapies.

Development of a mouse model of arecoline-induced oral mucosal fibrosis

OBJECTIVE

To develop a BALB/c mouse model of oral submucous fibrosis (OSF) induced by arecoline and to exhibit an accumulation of collagen and angiogenesis changes.

METHODS

BALB/c mice were randomly assigned to either the control (distilled water) or experimental group (arecoline) (n = 40). Eight mice from each group were sacrificed every 4 weeks since 8 weeks post treatment. Changes in histopathologic features, levels of collagen type I and collagen type III, and angiogenesis were measured.

RESULTS

In the 8th week, epithelium atrophy, collagen cumulation and micrangium pathologic changes in the lamina propria were observed in the oral mucosa. In the 20th week, hyaline degeneration of the connective tissues was observed on the tongue and palate mucosa. The angiogenesis and collagen type I changed significantly as the diseases advanced (P < 0.05); however, collagen type III was not statistically different.

CONCLUSIONS

An OSF model involving mice can be rapidly induced by drinking a high-dose of arecoline. OSF angiogenic changes in mice primarily decrease and collagen accumulation is mainly collagen type I.

Microenvironmental regulation of the progression of oral potentially malignant disorders towards malignancy

Oral potentially malignant disorders (OPMD) develop in a complex tissue microenvironment where they grow sustainably, acquiring oral squamous cell carcinoma (OSCC) characteristics. The malignant tumor depends on interactions with the surrounding microenvironment to achieve loco-regional invasion and distant metastases. Unlike abnormal cells, the multiple cell types in the tissue microenvironment are relatively stable at the genomic level and, thus, become therapeutic targets with lower risk of resistance, decreasing the risk of OPMD acquiring cancer characteristics and carcinoma recurrence. However, deciding how to disrupt the OPMD and OSCC microenvironments is itself a daunting challenge, since their microenvironments present opposite capacities, resulting in diverse consequences. Furthermore, recent studies revealed that tumor-associated immune cells also participate in the process of differentiation from OPMD to OSCC, suggesting that reeducating stromal cells may be a new strategy to prevent OPMD from acquiring OSCC characteristics and to treat OSCC. In this review, we discuss the characteristics of the microenvironment of OPMD and OSCC as well as new therapeutic strategies.

Early Stage Oral Submucous Fibrosis is Characterized by Increased Vascularity as Opposed to Advanced Stages

INTRODUCTION

The degree of vascularity of the diseased mucosa in Oral Submucous Fibrosis (OSMF) has always been a matter of debate with conflicting results. Knowledge of this aspect is important to understand pathogenesis of OSMF, which in future could be translated into therapeutic strategies.

AIM

In the present study, attempt has been made to investigate parameters like Mean Vascular Density (MVD), Total Vascular Area (TVA) and Mean Vascular Area (MVA) using CD34 antibody.

MATERIALS AND METHODS

Forty five previously untreated histopathologically diagnosed cases of OSMF were retrieved from archives and fifteen age and sex matched healthy volunteers without habits were included in the control group. Sections were immunohistochemically stained for CD 34 and morphometric analysis was performed. For statistical analysis ANOVA, Kruskal Wallis test and Mann Whitney U tests were used and p-values <0.05 were considered statistically significant.

RESULTS

MVD was more in Stage I OSMF followed by Control, Stage II and Stage III with statistically significant differences (p< 0.001). Statistically significant differences were observed in the MVD between control versus Stage III OSMF. Similarly, TVA was statistically significant when compared between control versus OSMF, control versus Stage II OSMF, control versus Stage III OSMF, Stage I versus Stage II OSMF, Stage I versus Stage III OSMF, and Stage II versus Stage III OSMF. For MVA, significant differences were between control versus OSMF, control versus Stage II OSMF, control versus Stage III OSMF, Stage I versus Stage III OSMF and Stage II versus Stage III OSMF.

CONCLUSION

Angiogenesis is seen in early stages of OSMF with decreasing trend in advanced stages. Decreased vascular areas seen in advanced stages could be attributed to the increasing fibrosis surrounding the blood vessels.

Oral submucous fibrosis: Newer proposed classification with critical updates in pathogenesis and management strategies

Oral submucous fibrosis (OSMF) is an oral precancerous condition characterized by inflammation and progressive fibrosis of the submucosal tissues resulting in marked rigidity and trismus. OSMF still remains a dilemma to the clinicians due to elusive pathogenesis and less well-defined classification systems. Over the years, many classification systems have been documented in medical literature based on clinical, histopathological, or functional aspects. However, none of these classifications have achieved universal acceptance. Each classification has its own merits and demerits. An attempt is made to provide and update the knowledge of classification system of OSMF so that it can assist the clinicians, beneficial in researches and academics in categorizing this potentially malignant disease for early detection, prompt management, and reducing the mortality. Along with this, pathogenesis and management have also been discussed.

Morphometric analysis of the mucosal vasculature in oral submucous fibrosis and its comparison with oral squamous cell carcinoma

Oral submucous fibrosis (OSMF) is a chronic fibrotic disorder in which the degree of vascularity has always been a matter of dispute; however, morphological studies of the blood vessels in OSMF have been sparse. This study was performed to assess the mucosal vasculature in normal oral mucosa, early and advanced OSMF, and well differentiated squamous cell carcinoma (WDSCC) using morphometry. The study included histologically diagnosed cases of early (n = 30) and advanced (n = 30) OSMF, and WDSCC (n = 30), with normal oral mucosa (n = 10) as a control. Morphometric image analysis of blood vessels was performed on H&E-stained sections for evaluation of vascular density, vascular luminal diameter, area and percentage area. A significant increase in all of the parameters was noted in the test groups relative to the controls. The mean vascular density and mean vascular percentage area were significantly increased in early OSMF and WDSCC relative to controls, and also in advanced OSMF and WDSCC in comparison with early OSMF. The vascularity increased progressively from normal to premalignancy and malignancy, emphasizing the importance of angiogenesis in tumor development and progression. The vascularity was increased in early OSMF and reduced in advanced OSMF, suggesting that inflammation may play a role in the early stages while progressive fibrosis may predispose to atrophy of the epithelium and subsequent malignant changes.

Oral submucous fibrosis: review on mechanisms of malignant transformation

Research studies focusing on various aspects of carcinogenesis in the background of fibrosis have advanced significantly in the recent past, allowing us to understand the mechanisms involved in malignant transformation of oral submucous fibrosis (OSF), the most prevalent potentially malignant oral disorder in South Asia. The role of areca nut as a carcinogen has been proven beyond doubt, with a large number of animal studies demonstrating its carcinogenicity, mutagenicity, and genotoxicity. Studies on the molecules implicated in cell cycle regulation, hypoxia, processes leading to DNA double-strand breaks, senescence, and many other pathways related to carcinogenesis have shown ample evidence for the malignant transformation in OSF induced by areca nut. More importantly, the understanding of the mechanisms of malignant transformation may lead to early diagnosis of oral squamous cell carcinoma arising in the background of OSF, which is now considered to constitute a clinicopathologically distinct disease, and the differences are believed to arise from the differential mechanisms of areca nut carcinogenesis. Therefore, the objective of this study is to review the literature on the various mechanisms leading to the malignant transformation of OSF.

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.

Immunohistochemical expression of CD34 and basic fibroblast growth factor (bFGF) in oral submucous fibrosis

Background:

Oral submucous fibrosis (OSMF) is an insidious chronic fibrotic condition that involves the oral mucosa and occasionally the pharynx and esophagus. Vascularity in OSMF has always been a matter of debate. The prevailing concept is that epithelial atrophy occurs due to lack of perfusion but the recent data challenges this concept. Therefore, the present study was conducted to evaluate the immunoreactivity of CD34 and basic fibroblast growth factor (bFGF) in different histological grades of OSMF. This might further shed light to the role of microvasculature in OSMF, so that the epithelial atrophy and resultant malignant transformation seen in the advanced stages might be elucidated.

Materials and Methods:

A total of 30 cases of OSMF were included in the study and mean vascular density (MVD) was calculated using CD34 and bFGF. Five cases of OSMF with dysplasia and 2 cases of OSMF turning malignant were added during the course of the study.

Results:

Mean vascular density was found to decrease significantly as the diseases advanced. Furthermore, vascularity increased significantly in cases of OSMF turning towards malignancy.

Conclusion:

Our study supports the concept of epithelial atrophy aftermath of lack of perfusion. There is reduced vascularity as the disease advances and this denies the systemic absorption of carcinogens, which affects the already compromised epithelium. Consequently, liberation of angiogenic factors occurs because of malignant transformation, which explains the neoangiogenesis and increased vascularity in OSMF turning towards malignancy. Further studies are required to identify the mechanism leading to carcinogenesis in the atrophied epithelium aftermath of fibrosis and decreased vascularity.

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.

An assessment of mast cells and myofibroblasts in denture-induced fibrous hyperplasia

OBJECTIVES

The pathogenesis of denture-induced fibrous hyperplasias has not been examined in detail to explain how tissue injury results in fibrous hyperplasia of the oral mucosa.

PATIENTS AND METHODS

We examined the presence of mast cells and myofibroblasts in 33 denture-induced fibrous hyperplasias (DIFH) compared with 10 healthy gingival tissues. The parameters examined included mast cell numbers, tissue distribution, degranulation, and cell subtypes using immunohistochemistry. The presence of myofibroblasts and their likely origin was also examined by double immunofluorescense staining. Furthermore, we investigated the synthesis of osteopontin and TGF-β, considered to be involved in the transformation of a fibroblast to a myofibroblast.

RESULTS

The results demonstrated that the mast cell numbers are significantly increased in the DIFH compared with non-disease controls. The mast cell localization in lesions was higher in the superficial areas with inflammatory cell infiltration compared with the deep fibrotic area (P < 0.01). The number of tryptase-positive mast cells was significantly higher compared with chymase-positive ones. The TGF-β- or osteopontin-positive cell infiltration into the lesion was found in high numbers. The presence of myofibroblasts was identified in 14 of 33 cases (42%), and some of these cells showed apoptosis when assessed by the TUNEL assay. On the survey of the origin of myofibroblasts, results showed αSMA and vimentin positivity indicating these transformed from fibroblasts.

CONCLUSION

These results are the first to show that mast cells and myofibroblasts can be detected in DIFH, indicating important roles of these cells in the pathogenesis of this lesion.