Copper chelation reduces early collagen deposition and preserves saliva secretion in irradiated salivary glands

Radiation therapy is a first-line treatment for head and neck cancer; however, it typically leads to hyposalivation stemming from fibrosis of the salivary gland. Current strategies to restore glandular function are dependent on the presence of residual functional salivary gland tissue, a condition commonly not met in patients with extensive fibrotic coverage of the salivary gland resulting from radiation therapy. Fibrosis is defined by the pathological accumulation of connective tissue (i.e., extracellular matrix) and excessive deposition of crosslinked (fibrillar) collagen that can impact a range of tissues and given that collagen crosslinking is necessary for fibrosis formation, inhibiting this process is a reasonable focus for developing anti-fibrotic therapies. Collagen crosslinking is catalyzed by the lysyl oxidase family of secreted copper-dependent metalloenzymes, and since that copper is an essential cofactor in all lysyl oxidase family members, we tested whether localized delivery of a copper chelator into the submandibular gland of irradiated mice could suppress collagen deposition and preserve the structure and function of this organ. Our results demonstrate that transdermal injection of tetrathiomolybdate into salivary glands significantly reduced the early deposition of fibrillar collagen in irradiated mice and preserved the integrity and function of submandibular gland epithelial tissue. Together, these studies identify copper metabolism as a novel therapeutic target to control radiation induced damage to the salivary gland and the current findings further indicate the therapeutic potential of repurposing clinically approved copper chelators as neoadjuvant treatments for radiation therapy.

Machine learning for detection and classification of oral potentially malignant disorders: A conceptual review

Oral potentially malignant disorders represent precursor lesions that may undergo malignant transformation to oral cancer. There are many known risk factors associated with the development of oral potentially malignant disorders, and contribute to the risk of malignant transformation. Although many advances have been reported to understand the biological behavior of oral potentially malignant disorders, their clinical features that indicate the characteristics of malignant transformation are not well established. Early diagnosis of malignancy is the most important factor to improve patients' prognosis. The integration of machine learning into routine diagnosis has recently emerged as an adjunct to aid clinical examination. Increased performances of artificial intelligence AI-assisted medical devices are claimed to exceed the human capability in the clinical detection of early cancer. Therefore, the aim of this narrative review is to introduce artificial intelligence terminology, concepts, and models currently used in oncology to familiarize oral medicine scientists with the language skills, best research practices, and knowledge for developing machine learning models applied to the clinical detection of oral potentially malignant disorders.

A combination treatment of low-dose dexamethasone and aspirin-triggered resolvin D1 reduces Sjögren syndrome-like features in a mouse model

Background

Sjögren syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and diminished secretory function of the salivary glands. Dexamethasone (DEX) resolves dry mouth and lymphocytic infiltration; however, this treatment is difficult to maintain because of multiple adverse effects (eg, osteoporosis and skin thinning); likewise, aspirin-triggered resolvin D1 (AT-RvD1) increases saliva secretion but cannot eliminate lymphocytic infiltration. Previous studies showed that a combination of low-dose DEX with AT-RvD1 before disease onset prevents SS-like features in a mouse model; however, this is not clinically practical because there are no reliable indicators of SS before disease onset. Therefore, the authors applied the combined treatment at disease onset to show its efficacy and comparative lack of adverse effects, so that it may reasonably be maintained over a patient's lifetime.

Methods

NOD/ShiLtJ mice were treated with ethanol (vehicle control), high-dose DEX alone, AT-RvD1 alone, or a combination of low-dose DEX with AT-RvD1 at disease onset for 8 weeks. Then saliva flow rates were measured, and submandibular glands were harvested for histologic analyses.

Results

A combined treatment of low-dose DEX with AT-RvD1 significantly decreased mast cell degranulation and lymphocytic infiltration, increased saliva secretion, and restored apical aquaporin-5 expression in submandibular glands of NOD/ShiLtJ mice.

Conclusions

Low-dose DEX combined with AT-RvD1 reduces the severity of SS-like manifestation and prevents the development of advanced and potentially irreversible damage, all in a form that can reasonably be administered indefinitely without the need to cease treatment because of secondary effects.

The role of matrixmetalloproteinase-2 expression by fibroblasts in perineural invasion by oral cavity squamous cell carcinoma

OBJECTIVES

The mechanisms of perineural invasion (PNI) in oral cavity squamous cell carcinoma are only partially understood, and no studies have specifically investigated the role of perineural fibroblasts in PNI. Here, we identified fibroblasts within the microenvironment of perineural invasion and assessed their expression of matrix metalloproteinase-2 (MMP-2).

MATERIALS AND METHODS

Tumor specimens from 12 patients with oral cavity squamous cell carcinoma and pathologically-confirmed perineural invasion were stained by immunohistochemistry (IHC) for vimentin (positive control) and MMP-2. Scoring was quantified and compared at nerves involved with PNI and nerves uninvolved with PNI.

RESULTS

All 12 patients had perineural fibroblasts around involved and uninvolved nerves as marked by vimentin IHC staining. Perineural fibroblasts had detectable MMP-2 expression at areas of perineural invasion in all 12 patients, but no patients had MMP-2 expression by fibroblasts at nerves without PNI.

CONCLUSION

MMP-2 is expressed by fibroblasts within the microenvironment of perineural invasion, and MMP-2 expression by fibroblasts is a possible mechanism of perineural invasion by oral cavity squamous cell carcinoma. MMP-2 may be an anti-cancer target among oral cavity squamous cell carcinoma patients with PNI.

Specialized pro-resolving receptors are expressed in salivary glands with Sjögren's syndrome

Our previous studies demonstrated that resolvin D1 (RvD1) and its aspirin-trigged (AT) form AT-RvD1, are effective in decreasing inflammation while restoring saliva flow rates in a Sjögren's syndrome (SS)-like mouse model before and after disease onset. Resolvins are specialized pro-resolving mediators (SPM) that actively regulate inflammation. However, we only have extensive data within the salivary glands for RvD1 and AT-RvD1, both of which bind to the receptor ALX/FPR2. As such, the presence of other SPM receptors is unknown within salivary glands. Therefore, the goal of this study was to determine the expression of SPM receptors in non-SS and SS patients. For this purpose, six human minor salivary glands from female subjects were analyzed by H&E using the Chisholm and Mason classification to determine the degree of lymphocytic infiltration. Next, confocal immunofluorescence analysis was performed to determine the presence and distribution of different SPM receptors in mucous acini and striated ducts. We observed diffuse presence of lymphocytic infiltration and clinical data were consistent with SS diagnosis in three patients. Moreover, confocal immunofluorescence analysis indicated the presence of the receptors ALX/FPR2, BLT1 and CMKLR1 in the mucous acini and striated ducts of both non-SS and SS patients. GPR32 was absent in SS and non-SS minor salivary glands. In summary, our results showed that various SPM receptors are expressed in non-SS and SS minor salivary glands, all of which may pose as potential targets for promoting pro-epithelial and anti-inflammatory/pro-resolution signaling on SS patients.

SPM Receptor Expression and Localization in Irradiated Salivary Glands

Radiation therapy-mediated salivary gland destruction is characterized by increased inflammatory cell infiltration and fibrosis, both of which ultimately lead to salivary gland hypofunction. However, current treatments (e.g., artificial saliva and sialagogues) only promote temporary relief of symptoms. As such, developing alternative measures against radiation damage is critical for restoring salivary gland structure and function. One promising option for managing radiation therapy-mediated damage in salivary glands is by activation of specialized proresolving lipid mediator receptors due to their demonstrated role in resolution of inflammation and fibrosis in many tissues. Nonetheless, little is known about the presence and function of these receptors in healthy and/or irradiated salivary glands. Therefore, the goal of this study was to detect whether these specialized proresolving lipid mediator receptors are expressed in healthy salivary glands and, if so, if they are maintained after radiation therapy-mediated damage. Our results indicate that specialized proresolving lipid mediator receptors are heterogeneously expressed in inflammatory as well as in acinar and ductal cells within human submandibular glands and that their expression persists after radiation therapy. These findings suggest that epithelial cells as well as resident immune cells represent potential targets for modulation of resolution of inflammation and fibrosis in irradiated salivary glands.

Plasma cell cheilitis: the diagnosis of a disorder mimicking lip cancer

Plasma cell cheilitis (PCC) is an inflammatory disorder of unknown etiology that affects the lip. It is characterized histologically by a dense infiltrate of plasma cells with a variety of clinical features. The response to different therapeutic modalities is controversial, especially regarding the effectiveness of corticosteroids. We present a case of a 56-year-old Caucasian man with a painful ulcerated and crusted area in the lower lip, resembling a squamous cell carcinoma or actinic cheilitis. Topical corticosteroid was used for one week, which resulted in partial regression and motivated a biopsy. The histological examination provided the diagnosis of PCC. The patient has been disease-free for six months. We also provide a discussion on the criteria of differential diagnosis and management of this rare condition.

Chronic paracoccidioidmycosis in a woman with Crohn Disease

We report a rare case of chronic paracoccidioidomycosis(PCM) in a woman with Crohn disease in the setting of treatment with azathioprine and mesalazine. Serum tests for antigens to Paracoccidioides brasiliensis, Histoplasma capsulatum, and Aspergillus fumigatus were negative. An incisional biopsy of an oral lesion with periodic acid-schiff and Grocott-methenamine silver stains revealed chronic granulomatous inflammation with multinucleated giant cells with Paracoccidioides brasiliensis within the cytoplasm, confirming the diagnosis of PCM.

Epstein-Barr Virus in Nasopharyngeal Carcinoma of Guatemalan and Brazilian Patients

BACKGROUND

Nasopharyngeal carcinoma (NPC) is highly associated with Epstein-Barr virus (EBV), particularly the undifferentiated nonkeratinizing subtype. Prevalence of EBV in NPC in countries such as Guatemala and Brazil has not been studied.

METHODS

We analyzed 19 cases of NPC, 11 from Guatemala and 8 from Brazil, for the presence of EBV by in situ hybridization and immunohistochemistry. Additionally, 19 hyperplastic adenoids from children were analyzed for EBV by in situ hybridization, 12 from Guatemala and 7 from Brazil.

RESULTS

All the NPC cases from Guatemala and 5 from Brazil were of the undifferentiated nonkeratinizing type. EBV-negative cases comprised 2 keratinizing NPC and 1 differentiated nonkeratinizing NPC. All undifferentiated nonkeratinizing NPC from both samples showed intense positivity for EBER, while LMP-1 only focally and scarcely expressed. EBER was positive in 75% and 43% of the adenoids from Guatemala and Brazil, respectively.

CONCLUSIONS

All undifferentiated nonkeratinizing NPC irrespective of origin from Guatemala or Brazil were highly associated with EBV.

Lysozyme Expression Can be Useful to Distinguish Mammary Analog Secretory Carcinoma from Acinic Cell Carcinoma of Salivary Glands

Lysozyme is an enzymatic marker of acinar and intercalated duct cells of normal salivary glands. The aim of this study was to verify whether lysozyme expression could be useful to distinguish acinic cell carcinoma (ACC) from its main mimic, mammary analog secretory carcinoma (MASC). For comparison, DOG1 expression was analyzed as well. Seventeen cases of ACC, 15 MASC, and 125 other salivary tumors were studied. Lysozyme expression was found in tumor cells as well as in secreted material of MASC (86.6 % of cases) and in ductal cells of epithelial-myoepithelial carcinoma (EMC-53.8 %), pleomorphic adenoma (PA-29.1 %) and polymorphous low-grade adenocarcinoma (PLGA-23.8 %). However, in ACC, lysozyme was not expressed. Three patterns of DOG1 staining were seen: apical-luminal, cytoplasmic, and mixed cytoplasmic/membranous. The apical-luminal pattern was detected in ductal cells of ACC (58.8 % of cases), EMC (38.4 %), adenoid-cystic carcinoma (AdCC-35.3 %), PA (8.3 %), and PLGA (4.8 %). These tumors also showed mixed membranous/cytoplasmic staining for DOG1. MASC, mucoepidermoid, and salivary duct carcinomas exhibited only DOG1 cytoplasmic staining. In conclusion, lysozyme cannot be used as a marker of acinar differentiation in salivary tumors. However, lysozyme expression can be helpful to distinguish MASC from ACC due to its high frequency in the former and absence in ACC. It is likely that in MASC, lysozyme expression may reflect a lactational-like secretory differentiation since lysozyme belongs to breast milk proteins. Regarding DOG1 expression, the apical-luminal pattern is related to acinar and intercalated duct differentiation whereas the cytoplasmic staining does not seem to be associated with a specific cellular phenotype.

Plasmacytoid-Type Cellular Differentiation in Polymorphous Low-Grade Adenocarcinoma

INTRODUCTION

Polymorphous low-grade adenocarcinoma (PLGA) occurs more frequently in minor salivary glands. The diagnosis of PLGA, in general, is not difficult but in occasional tumors showing limited invasion or in small biopsy specimens, PLGA may be confused with cellular pleomorphic adenoma (PA). Plasmacytoid cells, a usual component of PAs, have been considered helpful for correct tumor identification.

OBJECTIVE

The aim of this study was to verify the frequency (if any) of plasmacytoid-type cellular differentiation (PD) in PLGA.

MATERIALS AND METHODS

Thirty-two cases of PLGA were reviewed. PD was recognized in 2 cases (6.25%), in which immunohistochemical expression of AE1/AE3, CK7, CK14, vimentin, α-SMA, p63, S-100, calponin, GFAP, and Ki-67 was evaluated.

RESULTS

The 2 cases presented conventional areas of PLGA and variable quantities of cells with PD forming aggregates in the stroma and lining ductal structures. Cells with PD showed positivity for AE1/AE3, CK7, S-100, and vimentin and were negative for CK14, calponin, and GFAP in both cases. In case 1, cells with PD did not present α-SMA and p63 positivity whereas in case 2 they were positive, but for α-SMA such reactivity was restricted to cells forming solid aggregates.

CONCLUSION

Although PD in PLGA is rare, it is necessary to be aware of this possibility, particularly in small incisional biopsies and in PLGA with limited invasion, to avoid confusion with cellular PA.