Dimitrios Andreadis

Angiogenic Potential and Secretome of Human Apical Papilla Mesenchymal Stem Cells in Various Stress Microenvironments.

Stem cells from the apical papilla (SCAP) of human adult teeth are considered an accessible source of cells with angiogenic properties. The aims of this study were to investigate the endothelial transdifferentiation of SCAP, the secretion of pro- and antiangiogenic factors from SCAP, and the paracrine effects of SCAP when exposed to environmental stress to stimulate tissue damage. SCAP were exposed to serum deprivation (SD), glucose deprivation (GD), and oxygen deprivation/hypoxia (OD) conditions, individually or in combination. Endothelial transdifferentiation was evaluated by in vitro capillary-like formation assays, real-time polymerase chain reaction, western blot, and flow cytometric analyses of angiogenesis-related markers; secretome by antibody arrays and enzyme-linked immunosorbent assays (ELISA); and paracrine impact on human umbilical vein endothelial cells (HUVECs) by in vitro transwell migration and capillary-like formation assays. The short-term exposure of SCAP to glucose/oxygen deprivation (GOD) in the presence, but mainly in deprivation, of serum (SGOD) elicited a proangiogenesis effect indicated by expression of angiogenesis-related genes involved in vascular endothelial growth factor (VEGF)/VEGFR and angiopoietins/Tie pathways. This effect was unachievable under SD in normoxia, suggesting that the critical microenvironmental condition inducing rapid endothelial shift of SCAP is the combination of SGOD. Interestingly, SCAP showed high adaptability to these adverse conditions, retaining cell viability and acquiring a capillary-forming phenotype. SCAP secreted higher numbers and amounts of pro- (angiogenin, IGFBP-3, VEGF) and lower amounts of antiangiogenic factors (serpin-E1, TIMP-1, TSP-1) under SGOD compared with SOD or SD alone. Finally, secretome obtained under SGOD was most effective in inducing migration and capillary-like formation by HUVECs. These data provide new evidence on the microenvironmental factors favoring endothelial transdifferentiation of SCAP, uncovering the molecular mechanisms regulating their fate. They also validate the angiogenic properties of their secretome giving insights into preconditioning strategies enhancing their therapeutic potential.

Metastatic renal clear cell carcinoma in the parotid gland: A study of immunohistochemical profile and cell adhesion molecules (CAMs) expression in two cases

Metastasis of renal cell carcinoma (RCC) may involve any organ, including the parotid salivary gland. While the definition of salivary gland neoplasms with clear cell transformation can be concluded by the synchronous presence of areas showing typical morphology, sometimes the definition of a metastatic RCC in the parotid is difficult and the application of immunohistochemistry may support the clinical and radiographic observations in the final diagnosis. The aim of this paper was to describe the heterogeneous immunohistochemical features and, furthermore, to characterize the pattern of expression of cell adhesion molecules (CAMs) E-cadherin, β4-integrin, desmoglein-2, ICAM-1 and CD44s (HCAM) in two cases of metastatic parotid RCC.

Bilateral aplasia of parotid glands correlated with accessory parotid tissue.

Congenital absence of major salivary glands, especially the parotid gland, is a rare entity. It is usually monolateral and is not correlated with accessory salivary gland tissue. Aplasia of parotid gland may occur alone or in association with abnormalities of other salivary glands, first branchial arch developmental disturbances or other congenital anomalies.We report an interesting case of bilateral aplasia of the parotid glands together with bilateral accessory parotid tissue, without other congenital or developmental anomalies, and we describe the clinical and radiological findings.

Minor salivary glands of the lips: a novel, easily accessible source of potential stem/progenitor cells

ObjectivesCells with stem/progenitor properties have been detected in major salivary glands, but no data are available on their presence within minor salivary glands (MSGs). This study aimed to isolate and characterize potential stem/progenitor cells from human MSGs.Materials and methodsMSGs of the lower lip were surgically obtained during biopsy for Sjogren’s syndrome investigation that finally proved to be histologically normal. The established MSG cultures were assessed for morphology, proliferation, colony-forming-unit efficiency, multipotentiality, and immunophenotypic characteristics.ResultsA mixed population of fibroblast-like and a few flat-shaped epithelial-like cells was obtained. These cells were capable for osteogenic, adipogenic, and neurogenic differentiation. Evidence for strong stem cell potency was observed by the detection of early stem cell markers, like Nanog, Oct-3/4, and SSEA-3. These cells also expressed characteristic mesenchymal stem cell markers, including CD90-Thy1, CD105, CD49f, CD81, nestin, CD146, and Stro-1, but were negative for CD117/C-KIT, CD45, and CD271/NFG. In addition, positivity for keratins 7/8 in part of the population was indicative of an epithelial phenotype, whereas these cells were negative for aquaporin-1 expressed in acinar/myoepithelial cells during development.ConclusionsBased on these data, a cell population with stem/progenitor characteristics was primarily isolated from labial MSGs. The morphologic and immunophenotypic features indicated that this population is mixed with mesenchymal (mainly) and epithelial characteristics.Clinical relevanceDue to their large number and superficial distribution in labial mucosa, MSGs may be proposed as a potential easily accessible source of adult stem/progenitor cells for regenerative therapies of glandular organs with parenchymal pathology.

Immunohistochemical detection of E-cadherin in certain types of salivary gland tumours

OBJECTIVES To investigate the topography of E-cadherin and its possible correlation with the histological phenotype of salivary gland tumours. MATERIAL AND METHODS Archival formalin-fixed, paraffin-embedded sections of 54 benign and 56 malignant tumours and 24 samples of normal and inflamed salivary gland tissue were studied immunohistochemically using an Envision/horseraddish peroxidase (HRP) technique. RESULTS In normal and inflamed salivary gland samples, E-cadherin was expressed at the membrane of acinar, myoepithelial and ductal cells located at cell-cell contact points. Reduction and/or absence of E-cadherin was only observed in pleomorphic adenoma at the peripheral cells of the duct-like or island structures, or in the cells exhibiting plasmacytoid or stromal differentiation. Neoplastic epithelium in Warthins tumours and in myoepithelial and oncocytic adenomas was strongly positive. Furthermore, a weak to moderate loss of expression which was related to tissue tumour subtype was seen in malignant tumours such as: adenoid cystic carcinomas; polymorphous low-grade adenocarcinomas; acinic cell carcinomas; and mucoepidermoid low-grade, epithelial-myoepithelial, lymphoepithelial and squamous low-grade carcinomas. Moderate to extreme loss or alternative cytoplasmic non-functional expression were observed in cases of salivary ductal carcinoma, carcinosarcoma, myoepithelial carcinoma, oncocytic adenocarcinoma, unspecified adenocarcinoma and squamous high-grade carcinomas. CONCLUSION This study suggests a direct association of E-cadherin expression with neoplastic histologic phenotype, which is lost in the more undifferentiated and invasive epithelial salivary gland tumours.

Localized Tongue Amyloidosis in a Patient with Neurofibromatosis Type II

BackgroundLocalized Amyloidosis (AL) may rarely involve oral mucosa. This is the first known reported case describing the development of tongue AL in a 30-year-old patient with Neurofibromatosis (NF) type-2.CaseA female patient presented with a painless, well-circumscribed nodule of the tongue. Her medical history included NF type-2 with chromosome-22 abnormal karyotype (mosaicism), multiple intracranial and spinal meningiomas/schwannomas and unilateral blindness/deafness. The biopsy of the excised lesion of the tongue revealed subepithelial accumulation of an amorphous, nodular, fibrillar material positive for Congo red. Blood examination showed increased Thyroxine-T4 due to thyroid multinodular colloid goiter, but excluded any other hematological/immunological disorder or organ dysfunction. No recurrence was observed after a six-month follow-up.ConclusionThis case highlights the possibility of oral manifestations as the only sign of AL and reveals the unexpected co-existence of AL and NF 2, for the first time.

Myofibroma of the oral mucosa: a case report.

Objective: To report a case of coexisting irritation fibroma and myofibroma in oral mucosa. Clinical Presentation and Intervention: One case with two painless, nodular masses, adjacent to each other in the buccal mucosa, was clinically examined with a provisional diagnosis of irritation fibroma, salivary gland tumors, neurofibroma and schwannoma. Histological examination of the smaller swelling showed features of irritation fibroma, while the features of the other mass were compatible with myofibroma or leiomyoma. Additional immunohistochemical examination established the diagnosis of myofibroma. Conclusion: This was a case of a myofibroma that was clinically similar to an adjacent irritation fibroma, which highlights the possibility of misdiagnosis of a myofibroblastic tumor and underlines the importance of histologic examination together with immunohistochemical and/or histochemical analysis if necessary to establish the accurate diagnosis.

Bilateral Masseter and Internal Pterygoid Muscle Hypertrophy: A Diagnostic Challenge

Objective: To describe an unusual case of bilateral masseter and pterygoid muscle hypertrophy. Clinical Presentation and Intervention: A 53-year-old female patient presented with a bilateral, painless swelling at the parotid areas without improvement after using antibiotics/systemic corticosteroids/nonsteroidal anti-inflammatory agents. Her medical history included thyroid nodules, but no dental/occlusal disorders were observed. The initial differential diagnosis included salivary gland/jaw bone/masseter pathology, but the CT/MRI revealed only an increase in the size of the masseter and pterygoid muscles. The patient was informed of the benign nature of the swelling and was advised to discontinue the use of nonsteroidal anti-inflammatory agents. Conclusion: The bilateral hypertrophy of masseter muscles should be considered in differential diagnosis in cases of unilateral or bilateral swelling of the parotid or lateral mandible area.

Expression of matrix metalloproteinases 9 and 12 in actinic cheilitis.

AIM To investigate the role of matrix-degrading metalloproteinases 9, 12 (MMPs), as mediators of functional connective tissue damage in actinic cheilitis. METHODS Thirty five formalin-fixed, paraffin embedded specimens of actinic cheilitis, and twelve specimens of normal lower lip vermillion, which were obtained by the archives of the Department of Oral Medicine and Maxillofacial Pathology, were examined. From each block, 5 μm thick sections were cut and routinely stained with Hematoxylin and Eosin. Immunohistochemical studies were performed on 4-μm thick sections of formalin-fixed paraffin embedded actinic cheilitis lesions and of normal lower lip vermillion, for MMP-9 and MMP-12 in serial sections of our specimens. Appropriate positive and negative controls were performed to confirm the specificity of the staining reaction. MMP immunohistochemistry was evaluated using a semiquantitative immunoreactive score. RESULTS Haematoxylin and eosin staining revealed in actinic cheilitis lesions atrophic stratified squamous cell epithelium, or focally and irregularly hyperplastic of variable thickness, in some areas was observed marked keratin production. Varying degrees of epithelial dysplasia were noticed with a wide spectrum of change within the same specimen. Characteristic was the appearance of chronic inflammatory infiltration, and a band of amorphous acellular, basophilic change like solar elastosis (elastin replacement of collagen). In normal lower lip specimens weak and scanty positive expression of MMP-9 and MMP-12 was observed. Anti-MMP-9 antibody showed a weak reaction, in actinic cheilitis lesions, focal in the elastotic material, in chronic inflammatory cells and mostly in macrophages and neutrophils. Strong and in some cases diffused immunohistochemical expression of MMP-12 was detected in actinic cheilitis lesions in the areas of the fragmented, distorted and thickened elastic fibers. MMP-12 was also expressed in chronic inflammatory cells and mostly macrophages. MMP-12 was significantly higher in actinic cheilitis specimens compared with the normal lower lip specimens (P = 0.0029). CONCLUSION Our results suggest that especially MMP-12 may play an important role in remodeling events occurring in the connective tissue during long-term exposure to sunlight in the actinic cheilitis lesions.

Myofibroblasts and Transforming Growth Factor-Beta1 in Reactive Gingival Overgrowths

ABSTRACT Objectives The purpose of this study was to evaluate the oral health-related quality of life of patients treated with implant-supported mandibular overdentures and to compare the attachment systems used. Material and Methods The presence of myofibroblasts as well as transforming growth factor-beta1 was examined in twenty cases of fibrous epulis and 22 ossifying fibrous epulis, using immunohistochemistry. Results Myofibroblasts positive for alpha smooth muscle actin and vimentin but negative to desmin were found in 20% and 45% in fibrous epulis and ossifying fibrous epulis, respectively. Myofibroblasts were distributed in areas with and without inflammatory infiltration and their presence in inflammatory areas was not related with the degree of inflammatory infiltration. A percentage of 21 - 60% of fibroblasts and chronic inflammatory cells expressed transforming growth factor-beta1 in all cases. Conclusions These data suggest that transforming growth factor-beta1 and myofibroblasts contribute to the formation of collagenous connective tissue in fibrous epulis and ossifying fibrous epulis. Myofibroblasts are mainly presented in ossifying fibrous epulis than in fibrous epulis. It seems to be no relationship between the presence of myofibroblasts and the degree of inflammatory infiltration of the lesions.