Architectural Analysis of Picrosirius Red Stained Collagen in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma using Polarization Microscopy

Biomolecular alterations temporally anticipate microarchitectural modifications of collagen in oral tongue squamous cell carcinoma

High resolution analysis of collagen bundles could provide information on tumor onset and evolution. This study was focused on the microarchitecture and biomolecular organization of collagen bundles in oral tongue squamous cell carcinoma (OTSCC). Thirty-five OTSCC biopsy samples were analyzed by synchrotron-based phase-contrast microcomputed tomography and Fourier transform infrared imaging (FTIRI) spectroscopy. PhC-microCT evidenced the presence of reduced and disorganized collagen in the tumor area compared to the extratumoral (ExtraT) one. FTIRI also revealed a reduction of folded secondary structures in the tumor area, and highlighted differences in the peritumoral (PeriT) areas in relation with the OTSCC stage, whereby a significantly lower amount of collagen with less organized fibers was found in the PeriT stroma of advanced-OTSCC stages. Interestingly, no significant morphometrical mismatches were detected in the same region by PhC-microCT analysis. These results suggest that biomolecular alterations in the OTSCC stroma temporally anticipate structural modifications of collagen bundle microarchitecture.

Optical coherence tomography: Promising imaging technique for the diagnosis of oral mucosal diseases

OBJECTIVE

This review aims to summarize the latest application of optical coherence tomography (OCT) in oral mucosal diseases, promoting an accurate and earlier diagnosis of such disorders, which are difficult to be differentiated.

SUBJECTIVE AND METHODS

References on the application of OCT in oral mucosal diseases were mainly obtained from PubMed, Embase, Web of Science and Scopus databases, using the keywords: "optical coherence tomography and 'oral mucosa/oral cancers/oral potentially malignant diseases/oral lichen planus/oral leukoplakia/oral erythroplakia/discoid lupus erythematosus/oral autoimmune bullous diseases/oral ulcers/erythema multiforme/oral mucositis'".

RESULTS

It is found that OCT is showing a promising application potential in the early detection, diagnosis, differential diagnosis, monitoring of oral cancer and oral dysplastic lesions, as well as the delineation of tumor margins. OCT is also playing an increasingly important role in the diagnosis of oral potentially malignant disorders, oral mucosal bullous diseases, oral ulcerative diseases, erythema multiforme, and the early detection of oral mucositis.

CONCLUSION

Optical coherence tomography, as a novel optical technique featured by real-time, noninvasive, dynamic and high-resolution imaging, is of great use to serve as an adjunct tool for the diagnosis, differential diagnosis, monitoring and therapy evaluation of oral mucosal diseases.

Conditional Deletion of HIF-2α in Mouse Nucleus Pulposus Reduces Fibrosis and Provides Mild and Transient Protection From Age-Dependent Structural Changes in Intervertebral Disc

Hypoxia-inducible factors (HIFs) are critical to the development and homeostasis of hypoxic tissues. Although HIF-2α, one of the main HIF-α isoforms, is expressed in nucleus pulposus (NP) cells, its functions remain unknown. We deleted HIF-2α in the NP tissue using a notochord-specific FoxA2Cre allele to study HIF-2α function in the adult intervertebral disc. Unlike observations in HIF-1αcKO mice, fate mapping studies using Rosa26-mTmG reporter showed that HIF-2α loss in NP did not negatively impact cell survival or affect compartment development. Rather, loss of HIF-2α resulted in slightly better attributes of NP morphology in 14-month-old HIF-2αcKO mice as evident from lower scores of degeneration. These 14-month-old HIF-2αcKO mice also exhibited significant reduction in NP tissue fibrosis and lower collagen turnover in the annulus fibrosis (AF) compartment. Imaging-Fourier transform-infrared (FTIR) analyses showed decreased collagen and protein content in the NP and maintained chondroitin sulfate levels in 14-month-old HIF-2αcKO . Mechanistically, global transcriptomic analysis showed enrichment of differentially expressed genes with Gene Ontology (GO) terms related to metabolic processes and cell development, molecular functions concerned with histone and protein binding, and associated pathways, including oxidative stress. Noteworthy, these morphological differences were not apparent in 24-month-old HIF-2αcKO , indicating that aging is the dominant factor in governing disc health. Together these data suggest that loss of HIF-2α in the NP compartment is not detrimental to the intervertebral disc development but rather mitigates NP tissue fibrosis and offers mild but transient protection from age-dependent early degenerative changes. © 2022 American Society for Bone and Mineral Research (ASBMR).

En-face polarization-sensitive optical coherence tomography to characterize early-stage esophageal cancer and determine tumor margin

Current imaging tools are insufficiently sensitive to the early diagnosis of esophageal squamous cell carcinoma (ESCC). The application of polarization-sensitive optical coherence tomography (PS-OCT) to detect tumor-stroma interaction is an interesting issue in cancer diagnosis. In this translational study, we found that en-face PS-OCT effectively characterizes protruding, flat, and depressive type ESCC regardless of animal or human specimens. In addition, the tumor contour and margin could also be drawn and determined on a broad en-face view. The determined tumor margin could be in the proximity of 2 mm to the actual tumor margin, which was proved directly using histology.

Natural stain (Kumkum) formulated by the extract of Curcuma aromatica and slaked lime in histostaining of oral tissues: An observational study

Background

The pharmacological actions of Curcuma aromatica (wild turmeric) such as anti-inflammatory, antitumor, antifungal, antimicrobial and wound healing have been recognized since ages. However, its role as a natural histological stain has not been explored till date.

Aim

To evaluate the efficacy of natural substance-Kumkum prepared from the extract of C. aromatica and slaked lime in staining the biopsied oral tissues.

Materials and Methods

A cohort study that used 60 formalin fixed paraffin embedded soft and hard tissue specimens from institutional archives were subjected to sectioning and stained using Kumkum and hematoxylin and eosin (H and E). The slides were evaluated for their staining efficacy and results were statistically analyzed using Wilcoxon signed-rank test and Independent 't' test.

Results

The mean of the overall parameters assessed for staining efficacy did not show statistically significant difference between the study groups in normal and pathological specimens for tooth (P = 0.410 and 0.484), bone (P = 0.133 and 0.157) and soft tissues (P = 0.186 and 0.113), respectively. This suggests that Kumkum staining efficacy is equivalent to that of routine H and E for oral tissues. Structures such as dentinoenamel junction, dentinal tubules, incremental lines of cementum, reversal and resting lines, osteocytic canaliculi, mature and immature bone could be appreciated better in Kumkum stained slides, thereby rendering a special staining property to Kumkum stain.

Conclusion

To our knowledge, this study is the first of its kind to have used Kumkum stain obtained from C. aromatica for the differentiation of the components of tooth, bone and soft tissue structures in histostaining of oral tissues. The naturally prepared Kumkum stain possesses dual staining property both in routine and differential staining. This facilitates diagnosis of fibro-osseous lesions, bony, collagen and muscular pathologies. The natural stain also finds application in forensic odontology for age estimation.

Detection of Oral Dysplastic and Early Cancerous Lesions by Polarization-Sensitive Optical Coherence Tomography

Detection of oral dysplastic and early-stage cancerous lesions is difficult with the current tools. Half of oral cancers are diagnosed in a late stage. Detection of early stromal change to predict malignant transformation is a new direction in the diagnosis of early-stage oral cancer. The application of new optical tools to image stroma in vivo is under investigation, and polarization-sensitive optical coherence tomography (PS-OCT) is potentially one of those tools. This is a preliminary study to sequentially image oral stromal changes from normal, hyperplasia, and dysplasia to early-stage cancer by PS-OCT in vivo. We used 4-Nitroquinoline-1-oxide drinking water to induce dysplasia and early-stage oral cancer in 19 K14-EGFP-miR-211-GFP transgenic mice. A total of 8 normal, 12 hyperplastic, 11 dysplastic, and 4 early-stage cancerous lesions were enrolled. A new analytic process of PS-OCT imaging was proposed, called an en-face birefringence map. From the birefringence map, the sensitivity, specificity, positive predictive value, and negative predictive values to detect dysplasia and early-stage cancer were 100.00%, 95.00%, 93.75%, and 100.00%, respectively, and the kappa value of these images between two investigators was 0.942. The mean size of malignant lesions detected in this study is 1.66 ± 0.93 mm. This pilot animal study validates the use of PS-OCT to detect small and early-stage oral malignancy with high accuracy and consistency.

An in vitro tissue model for screening sustained release of phosphate-based therapeutic attenuation of pathogen-induced proteolytic matrix degradation

Tissue response to intestinal injury or disease releases pro-inflammatory host stress signals triggering microbial shift to pathogenic phenotypes. One such phenotype is increased protease production resulting in collagen degradation and activation of host matrix metalloproteinases contributing to tissue breakdown. We have shown that surgical injury depletes local intestinal phosphate concentration triggering bacterial virulence and that polyphosphate replenishment attenuates virulence and collagenolytic activity. Mechanistic studies of bacterial and host protease expression contributing to tissue breakdown are difficult to achieve in vivo necessitating the development of novel in vitro tissue models. Common techniques for screening in vitro protease activity, including gelatin zymography or fluorogenic protease-sensitive substrate kits, do not readily translate to 3D matrix degradation. Here, we report the application of an in vitro assay in which collagenolytic pathogens are cultured in the presence of a proteolytically degradable poly(ethylene) glycol scaffold and a non-degradable phosphate and/or polyphosphate nanocomposite hydrogel matrix. This in vitro platform enables quantification of pathogen-induced matrix degradation and screening of sustained release of phosphate-based therapeutic efficacy in attenuating protease expression. To evaluate matrix degradation as a function of bacterial enzyme levels secreted, we also present a novel method to quantify hydrogel degradation. This method involves staining protease-sensitive hydrogels with Sirius red dye to correlate absorbance of the degraded gel solution with hydrogel weight. This assay enables continuous monitoring and greater accuracy of hydrogel degradation kinetics compared to gravimetric measurements. Combined, the proposed in vitro platform and the presented degradation assay provide a novel strategy for screening efficacy of therapeutics in attenuating bacterial protease-induced matrix degradation.

Stromal desmoplasia as a possible prognostic indicator in different grades of oral squamous cell carcinoma

Introduction

One of the major aspects of tumor cell invasion and metastasis is the interaction between cancer cells and the extracellular matrix component. The invasion of epithelial tumor cells into the underlying connective tissue stroma causes dynamic changes in its microenvironment, which can be seen as radical changes in the stroma. The characteristics of the stroma in relation to the invading malignant epithelial cells and the interdependence between the stroma and the tumor cells are always a matter of discussion and interest.

Aim

The aim of this study is to predict the biological behavior of oral squamous cell carcinoma (OSCC) by evaluating stromal desmoplasia and its possible use as important prognostic indicators.

Objective

To assess the desmoplastic reaction in varying histopathological grades of OSCC.

Materials and Methods

The study included a total of 30 histopathologically prediagnosed cases of OSCC (well, moderate and poorly differentiated grades of OSCC). Picrosirius red stain in conjunction with polarizing microscope was used to evaluate the stromal desmoplastic reaction.

Results

The results of the study revealed that, in the initial grades, cancer invasion induces a desmoplastic reaction, whereas in the later stages, there is degradation of the stroma, thereby facilitating tumor invasion.

Conclusion

The study would emphasize the importance of stromal desmoplasia as a prognostic indicator and may help to reflect the biological diversity of oral cancer and predict the clinical outcomes.

Analysis of stromal mucin in oral epithelial dysplasia & oral squamous cell carcinoma- A histochemical study

Background

Mucins are glycoproteins that act as a selective molecular barrier and its alterations usually accompany the carcinogenesis.

Aim

To evaluate the transition of mucins in the grades of oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) using histochemical stains.

Materials & Method

A total of 66 samples of variable grades of OED and OSCC and each section was stained with PAS, Alcian blue- PAS (AB-PAS) and Aldehyde fuschin - Alcian blue (AF-AB). Mucins pattern and intensity were examined at 5 randomly selected fields on 10x magnification.

Results

1. PAS stain - Predominantly OED and OSCC showed a diffuse pattern with a gradual decrease in intensity in OED and overall a weak intensity in OSCC. 2. AB-PAS stain - Neutral mucins showed gradual increase in its intensity in grades of OED and OSCC with no predominant pattern. The intensity for the acid mucins remains weak in all the grades of OED and OSCC with diffuse distribution, except in higher grades of OED and OSCC. 3. AF- AB stain - For sulphated mucins, in OED a focal and diffuse pattern was observed in OSCC with minimal intensity. The carboxylated mucin was absent in both.

Conclusion

Mucins undergo change in its pattern and intensity in varying grades of OED/OSCC. Although in GIT and other mucosa, the expression of altered mucin is a recognized factor, seldom research has been done in OED and OSCC. Thus, the present study could be the stepping stone in the exploration of mucinous alteration in OED and OSCC.

Transforming Growth Factors α and β Are Essential for Modeling Cholangiocarcinoma Desmoplasia and Progression in a Three-Dimensional Organotypic Culture Model

To gain insight into the cellular and molecular interactions mediating the desmoplastic reaction and aggressive malignancy of mass-forming intrahepatic cholangiocarcinoma (ICC), we modeled ICC desmoplasia and progression in vitro. A unique three-dimensional (3D) organotypic culture model was established; within a dilute collagen-type I hydrogel, a novel clonal strain of rat cancer-associated myofibroblasts (TDF_SM) was co-cultured with a pure rat cholangiocarcinoma cell strain (TDE_CC) derived from the same ICC type as TDF_SM. This 3D organotypic culture model reproduced key features of desmoplastic reaction that closely mimicked those of the in situ tumor, as well as promoted cholangiocarcinoma cell growth and progression. Our results supported a resident liver mesenchymal cell origin of the TDF_SM cells, which were not neoplastically transformed. Notably, 3D co-culturing of TDE_CC cells with TDF_SM cells provoked the formation of a dense fibrocollagenous stroma in vitro that was associated with significant increases in both proliferative TDF_SM myofibroblastic cells and TDE_CC cholangiocarcinoma cells accumulating within the gel matrix. This dramatic desmoplastic ICC-like phenotype, which was not observed in the TDE_CC or TDF_SM controls, was highly dependent on transforming growth factor (TGF)-β, but not promoted by TGF-α. However, TGF-α was determined to be a key factor for promoting cholangiocarcinoma cell anaplasia, hyperproliferation, and higher malignant grading in this 3D culture model of desmoplastic ICC.