Role of osteopontin in oral epithelial dysplasia, oral submucous fibrosis and oral squamous cell carcinoma

Background

Inflammatory cells and cytokines in the chronically injured mucosa promote fibrosis in the oral submucous fibrosis (OSF) fibrotic milieu. Osteopontin (OPN) is a wound-healing mediator that upregulates the inflammatory response and is involved in the malignancy and fibrosis of multiple organ systems.

Objectives

We investigated the expression of OPN in oral potentially malignant disorders (OPMDs) and oral squamous cell carcinomas (OSCCs) to determine its role in the malignant transformation and fibrosis of oral tissues. The expression of OPN in OPMDs and OSCCs was compared and correlated, and the role of OPN as a fibrotic mediator in OSF was explained.

Study Design

A total of 30 cases of normal mucosa and OPMDs (mild dysplasia, severe dysplasia, OSF and OSCCs) were studied by purposive sampling. In these groups, OPN immunoreactivity was examined and correlated with clinical findings.

Results

In mild dysplasia, OPN expression was restricted to the basal cell layer with moderate staining intensity. In severe dysplasia, it was extremely intense and extended throughout the epithelium. In the OSF, OPN expression was moderate in the perinuclear areas of the basal cell layer. The expression of OPN was very strong in OSCC. A flow diagram explaining the profibrotic role of OPN in OSF has been provided.

Conclusion

A positive role of OPN in both pathogenesis and malignant transformation of OPMDs and OSCC has been demonstrated.

A five-step risk management process for geriatric dental practice during SARS-CoV-2 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an RNA virus that causes coronavirus infection (COVID-19). COVID-19 is a highly contagious disease transmitted through respiratory droplets, saliva and other contact routes. Within 10 months of its outbreak, SARS-CoV-2 has infected more than 23 million people around the world. Evidence suggests that older adults are the most vulnerable to infection and have an increased risk of mortality. Reduced immunity and underlying medical conditions make them risk-prone and vulnerable to critical care. Older adults affected with the SARS-CoV-2 virus present with distinct clinical manifestations necessitating specific treatment needs and management protocols. While it is crucial to prevent the spread of novel coronavirus (2019-nCoV), the role of oral healthcare workers in addressing the specific needs of ageing adult patients by adopting specific guidelines and appropriate infection control protocols is timely. This paper aims to develop specific guidelines and protocols for the dental management of geriatric patients during the COVID-19 pandemic.

The role of Ki-67, p16, CD34, Bcl-2, cyclooxygenase-2 in the pathogenesis of proliferative verrucous leukoplakia

CONTEXT

Proliferative verrucous leukoplakia (PVL) is a highly persistent and aggressive oral pre-malignant lesion with an obscure etiopathogenesis and a malignant transformation rate of 85-100%.

AIMS

The aim of the present study is to assess the role of Ki-67, p16, CD34, Bcl-2, cyclooxygenase-2 (COX-2) in the spectrum of PVL to ascertain their role in its etiopathogenesis.

SETTINGS AND DESIGN

A retrospective chart analysis was carried out on a series of seven confirmed cases of PVL, which were followed-up for 2 years.

SUBJECTS AND METHODS

Immunohistochemical appraisal of these cases was carried out by a panel of markers, related to cell proliferation, cell cycle regulation, angiogenesis, apoptosis and inflammation. The expression of these markers was correlated with patients' clinicopathological profile.

STATISTICAL ANALYSIS USED

The frequency distribution of the group data was analyzed.

RESULTS

The latest labeling index of Ki-67 in our cases ranged from 8.18 to 12.6. p16 was positive in 3/7 cases. Bcl-2 expression was moderately positive in 2/7 cases. All cases were intensely positive for COX-2 staining. Microvascular density assessed by CD34 staining ranged from 11 to 20/high power fields. One case which transformed into squamous cell carcinoma demonstrated increased Ki-67, Bcl-2, COX-2, CD34 expression, but negative p16 and Bcl-2 expression.

CONCLUSIONS

Application of these markers in understanding the behavior of PVL suggests that an imbalance between the proliferation apoptosis dynamics of the lesion accompanied by an increase in inflammation and angiogenesis underlie the molecular pathogenesis of the PVL spectrum.

An erupted odontoma associated with pigmentation: a histogenetic and histological perspective

Odontomas are hamartomatous malformations of odontogenic origin composed of all the structures that form the tooth. Pigmentation associated with odontomas is rare, with only two cases reported in the literature. The genesis of this composite malformation is attributable to the organizational failure of the developing odontogenic apparatus leading to abnormal morphodifferentiation. Although some odontomas erupt into the oral cavity, it defies the existing views of normal physiologic tooth movement thus raising questions over the use of this term. Here, we review a case of large odontoma in a 23-year-old male surfacing into the oral cavity from its intraosseous location. The unusual occurrence of melanotic pigmentation in the odontogenic epithelial rests was demonstrated by Mason Fontana special stain. The histogenesis of this unusual entity and explanation to its possible occurrence is discussed.

Lobodontia: the unravelling of the wolf teeth

Abnormalities of tooth shape and size generally coexist, as both are determined during the morphodifferentiation stage of odontogenesis. This report describes a case of lobodontia exhibiting multiple dental anomalies of which, "fang like" cuspids, multituberculism of molars, hypodontia along with severe generalized microdontia are distinctive. Radiographic features, diagnostic convolutions, differential diagnosis and clinical significance have also been highlighted.

Germ cell abnormalities in streptozotocin induced diabetic mice do not correlate with blood glucose level

PURPOSE

To assess the effect of streptozotocin induced hyperglycemia on germ cell integrity, DNA ploidy and methylation status for a period of two spermatogenesis cycles in adult male Swiss albino mice.

METHODS

Streptozotocin injected mice were monitored for hyperglycemia at a regular interval for a period of 36 and 72 days. The DNA integrity in epididymal spermatozoa was determined by the comet assay. Flow cytometric analysis was done in germ cells to assess the DNA ploidy. The global methylation analysis in germ cells was done by 5-methyl cytosine immunostaining.

RESULTS

Streptozotocin administration successfully resulted in hyperglycemic response which significantly affected serum testosterone level, sperm DNA integrity and DNA ploidy at the end of 36 days. However, no changes were observed in either epididymal sperm concentration or germ cell methylation status. In contrast, at the end of 76 days, although serum testosterone level, sperm DNA integrity and DNA ploidy status were unperturbed significantly in hyperglycemic group, the epididymal sperm concentration and methylation status of preleptotene/zygotene cells were significantly altered. Importantly, an attempt to find out the association between the blood glucose levels and the abnormalities in hyperglycemic group failed to demonstrate any correlation.

CONCLUSIONS

The germ cell abnormalities observed in hyperglycemic group could be interpreted as a primary effect of streptozotocin and not due to hyperglycemia. Our results call for further evaluation of streptozotocin before its application to study the hyperglycemic responses on male germ cells.