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

Correlation between Vascularity and Advancing Histological Grades of Oral Submucous Fibrosis with a Plausible Role in Malignisation: Systematic review of a persisting matter of conflict

Objectives

This study aimed to quantify the vascularity in histological grades of oral submucous fibrosis (OSMF) and to determine if there is any connection between vasculogenesis and malignisation. Recent studies show no significant change in vascularity as the stage advances as opposed to the conventional concept.

Methods

A comprehensive database search until December 2022 was conducted for published articles on vascularity in OSMF following preferred reporting items for systematic reviews and meta-analyses guidelines.

Results

A total of 98 articles were screened of which 13 were included for systematic evaluation. The study included 607 cases, with a definite predilection for the male gender. Of the 13 studies, 11 evaluated mean vascular density. In more than half of the studies, the vascularity decreased as the stage advanced. Similar results were obtained for endothelial cells/μm2, mean vascular area percentage and mean vascular area.

Conclusion

The present review supports the prevailing concept that vascularity decreases with the advancement of the OSMF stage. This denies the systemic absorption of carcinogens into the circulation with resultant longer exposure of compromised epithelium and malignisation.

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.

Epithelial atrophy, fibrosis and vascularity correlation with epithelial dysplasia in oral submucous fibrosis, a prospective study

Background:

The pathogenesis of oral submucous fibrosis (OSF) still remains conflicting and has been linked to alterations in epithelial thickness, fibrosis, and vascularity. Although changes in these individual parameters have been extensively studied in relation to epithelial dysplasia their combined relation with dysplasia has not been studied much. Any such relation, if present, may further help in understanding this disease process. Therefore, the aim of this study was to assess the relationship between epithelial thickness, fibrosis, and vascularity with dysplasia in OSF.

Materials and Methods:

The study consisted of 30 OSF patients. Incisional biopsy was taken from the most fibrosed area of the buccal mucosa. Hematoxylin–Eosin-stained slides were assessed for epithelial thickness, fibrosis, and vascularity using image analysis software. The slides were also assessed for epithelial dysplasia. Relationship of epithelial atrophy, fibrosis, and vascularity with dysplasia was assessed using one-way ANOVA. Pearson's correlation coefficient was used for evaluating the relationship between epithelial thickness, fibrosis, and vascularity.

Results:

Epithelial dysplasia was found in all patients. Eleven patients had mild (36. 67%), thirteen had moderate (43.33%), and six had severe (20%) dysplasia. None of the parameters were found to have a significant relationship with dysplasia. However, moderate and positive correlation was found between epithelial thickness and fibrosis. This relation was statistically significant.

Conclusion:

Positive correlation between epithelial thickness and fibrosis in present study therefore contradicts the hypothesis of fibrosis induced epithelial atrophy. As dysplasia is influenced by multiple factors therefore habits and burning sensation needs to be incorporated in future studies assessing dysplasia in OSF.

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.

VEGF gene transfection restores the angiogenesis of oral submucous fibrosis in mice

Background

To explore the effectiveness of adenovirus-enhanced green fluorescent protein-vascular endothelial growth factor165 (AD-EGFP-VEGF165) transfection on fibroblasts from mice, and we assessed whether VEGF165 restores the angiogenesis of oral submucous fibrosis (OSF) in mice.

Methods

AD-EGFP-VEGF165 and AD-EGFP were transfected into fibroblasts from mouse buccal tissues in vitro. The expression of VEGF before and after transfection was detected by RT-qPCR and ELISA in each group of fibroblasts. Fifteen OSF mice (pre-experimental construction) were randomly divided into 3 groups, and equal amounts of AD-EGFP-VEGF165 virus, AD-EGFP virus, and saline were injected into the buccal submucosal tissue of OSF mice. The expression of VEGF and local tissue angiogenesis were observed and measured in each group of animals.

Results

The Ad-EGFP-VEGF165-transfected fibroblasts increased human and mouse VEGF expression compared to the Ad-EGFP group and control group (P<0.05). The buccal submucosal tissue of mice was injected with Ad-EGFP-VEGF165 after the 6th day, and the expression of VEGF was effectively expressed in AD-EGFP-VEGF165 group (P<0.05), while no positive expression observed in other groups. and the number of microvessels in the AD-EGFP-VEGF165 group increased significantly compared to the other groups (P<0.05).

Conclusions

Ad-EGFP-VEGF165 can be successfully transfected into fibroblasts from mice, and restored the angiogenesis of OSF in mice.

Oral Submucous Fibrosis: A Review on Biomarkers, Pathogenic Mechanisms, and Treatments

Oral submucous fibrosis (OSF) is a collagen deposition disorder that affects a patient’s oral function and quality of life. It may also potentially transform into malignancy. This review summarizes the risk factors, pathogenic mechanisms, and treatments of OSF based on clinical and bio-molecular evidence. Betel nut chewing is a major risk factor that causes OSF in Asia. However, no direct evidence of arecoline-induced carcinogenesis has been found in animal models. Despite identification of numerous biomarkers of OSF lesions and conducting trials with different drug combinations, clinicians still adopt conservative treatments that primarily focus on relieving the symptoms of OSF. Treatments focus on reducing inflammation and improving mouth opening to improve a patient’s quality of life. In conclusion, high-quality clinical studies are needed to aid clinicians in developing and applying molecular biomarkers as well as standard treatment guidelines.

[Relationship among areca nut, intracellular reactive oxygen species, and autophagy]

The relationship between areca nut as a primary carcinogen and oral cancer has been widely concerned. Areca can change the levels of reactive oxygen species (ROS) and autophagy in cells, and the levels of ROS and autophagy are closely related to the occurrence and development of tumors. This paper reviewed the relationships among areca nut, intracellular ROS, and autophagy.

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.

Dietary Fatty Acids and Other Nutrients in Relation to Inflammation and Particularly to Oral Mucosa Inflammation. A Literature Review

Oral mucosa is site of inflammatory process development. When they are chronic, they provide a microenvironment based on cytokines and inflammatory mediators that contribute to cancer initiation, progression, invasion, and metastasis. Certain dietary fatty acids (FAs) have immunomodulatory, inflammatory, and antiinflammatory effects. This review examined the literature on inflammation, mainly referred to the oral mucosa, and its association with dietary FAs and other nutrients. A Pubmed search of studies published in English until June 2018 was carried out. N-3 FAs have shown immunomodulatory and antiinflammatory activity in certain human diseases. These FAs and their mediators may inhibit inflammation, angiogenesis, and cancer via multiple mechanisms. Studies on cellular models of murine and human intestinal mucosa indicate association between dietary n-3 FA intake and the inflammatory state of mucosa membranes. Nevertheless scarce information on the association between dietary FAs and oral inflammation could be found. Based on the evidence, we hypothesize that n-3 FAs reduce the oral mucosa inflammation thus decreasing the risk of developing precancerous lesions and cancer. Molecular and clinical studies referred to this topic should be carried out as a contribution to the oral cancer prevention.

Ultrasonographic evaluation of submucosal thickness in oral submucous fibrosis patients: a cross-sectional study

Purpose

To evaluate the role of ultrasonography in oral submucous fibrosis (OSMF) patients.

Material and methods

A total of 150 subjects were divided equally into six groups (Group I: 25 healthy subjects; Group II: 25 healthy subjects with habit; Group III: 25 OSMF stage I; Group IV: 25 OSMF stage II; Group V: 25 OSMF stage III; and Group VI: 25 stage OSMF IVA). The grading of OSMF were done according the clinical classification given by Khanna and Andrade (2005). After fulfilling inclusion and exclusion criteria each subject underwent extraoral ultrasonographic evaluation of submucosal thickness and vascularity in terms of peak systolic velocity (PSV), bilaterally on buccal and labial mucosa. Furthermore, statistical comparison of each group was done, and sensitivity and specificity of USG measurements was obtained in comparison with clinical diagnosis. The statistical analysis was performed using SPSS ver. 20.0.

Results

A statistically significant increase in mean submucosal thickness was shown, and a decrease in PSV with the advancement of severity of the OSMF. In ultrasonographic diagnosis of OSMF, the reported submucosal thickness had a sensitivity, specificity, PPV, NPV, and accuracy was 80%, 100%, 100%, 71.4%, and 87%, respectively, but PSV failed to classify the lesion.

Conclusions

Because the severity of the disease showed a direct relationship with submucosal thickness and an inverse relationship with PSV, habit-induced mucosal alteration in submucosal thickness can be seen on USG, which cannot be appreciated on clinical examination. Hence, USG can be a promising tool for early diagnosis, assessment of the severity, and evaluation of prognosis of OSMF.

Angiogenesis and Fibrogenesis in Oral Submucous Fibrosis: A Viewpoint

Oral submucous fibrosis (OSF) is characterized by excessive fibrosis of submucosa. The degree of vascularity in OSF has always been a matter of debate. Angiogenesis is the key mechanism involved in regeneration and repair. It also plays an important role in various pathologic conditions. Angiogenesis may contribute to the progression of fibrosis in fibrotic disorders. Inhibition of pathological angiogenesis is considered to be a new strategy for the treatment of various fibrotic disorders. In OSF, angiogenesis can be related to progression fibrosis. This article briefly describes the role of angiogenesis in pathogenesis of fibrosis in OSF and the importance of inhibition of pathologic angiogenesis in its prevention and treatment.

CLINICAL SIGNIFICANCE

Understanding the association between angiogenesis and fibrogenesis can help in developing new therapeutic strategies for treatment of OSF.

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.

Epithelial atrophy in oral submucous fibrosis is mediated by copper (II) and arecoline of areca nut

Exposure of oral cavity to areca nut is associated with several pathological conditions including oral submucous fibrosis (OSF). Histopathologically OSF is characterized by epithelial atrophy, chronic inflammation, juxtaepithelial hyalinization, leading to fibrosis of submucosal tissue and affects 0.5% of the population in the Indian subcontinent. As the molecular mechanisms leading to atrophied epithelium and fibrosis are poorly understood, we studied areca nut actions on human keratinocyte and gingival fibroblast cells. Areca nut water extract (ANW) was cytotoxic to epithelial cells and had a pro-proliferative effect on fibroblasts. This opposite effect of ANW on epithelial and fibroblast cells was intriguing but reflects the OSF histopathology such as epithelial atrophy and proliferation of fibroblasts. We demonstrate that the pro-proliferative effects of ANW on fibroblasts are dependent on insulin-like growth factor signalling while the cytotoxic effects on keratinocytes are dependent on the generation of reactive oxygen species. Treatment of keratinocytes with arecoline which is a component of ANW along with copper resulted in enhanced cytotoxicity which becomes comparable to IC(50) of ANW. Furthermore, studies using cyclic voltammetry, mass spectrometry and plasmid cleavage assay suggested that the presence of arecoline increases oxidation reduction potential of copper leading to enhanced cleavage of DNA which could generate an apoptotic response. Terminal deoxynucleotidyl transferase dUTP Nick End Labeling assay and Ki-67 index of OSF tissue sections suggested epithelial apoptosis, which could be responsible for the atrophy of OSF epithelium.