Endothelial-Initiated Crosstalk Regulates Dental Pulp Stem Cell Self-Renewal.

Interactions with the microenvironment modulate the fate of stem cells in perivascular niches in tissues (e.g., bone) and organs (e.g., liver). However, the functional relevance of the molecular crosstalk between endothelial cells and stem cells within the perivascular niche in dental pulps is unclear. Here, we tested the hypothesis that endothelial cell-initiated signaling is necessary to maintain self-renewal of dental pulp stem cells. Confocal microscopy showed that ALDH1high and Bmi-1high stem cells are preferentially localized in close proximity to blood vessels in physiological human dental pulps. Secondary orosphere assays revealed that endothelial cell-derived factors (e.g., interleukin-6 [IL-6]) promote self-renewal of dental pulp stem cells cultured in low-attachment conditions. Mechanistic studies demonstrated that endothelial cell-derived IL-6 activates IL-6R (IL-6 Receptor) and signal transducer and activator of transcription 3 (STAT3) signaling and induces expression of Bmi-1 (master regulator of stem cell self-renewal) in dental pulp stem cells. Transplantation of dental pulp stem cells stably transduced with small hairpin RNA (shRNA)-STAT3 into immunodeficient mice revealed a decrease in the number of blood vessels surrounded by ALDH1high or Bmi-1high cells (perivascular niches) compared to tissues formed upon transplantation of vector control stem cells. And finally, in vitro capillary sprouting assays revealed that inhibition of IL-6 or STAT3 signaling decreases the vasculogenic potential of dental pulp stem cells. Collectively, these data demonstrate that endothelial cell-derived IL-6 enhances the self-renewal of dental pulp stem cells via STAT3 signaling and induction of Bmi-1. These data suggest that a crosstalk between endothelial cells and stem cells within the perivascular niche is required for the maintenance of stem cell pools in dental pulps.

Early dental management of patients with Mobius syndrome.

OBJECTIVE(S): The aim of this study was to evaluate the orofacial manifestations in patients with Mobius syndrome (MS), establish an early adequate dental treatment and discuss the possible etiology of all cases examined based on information about the gestational intercurrences. DESIGN: Prospective study. SETTING: Special Care Dentistry Center, School of Dentistry, University of Sao Paulo, Brazil. Subject(s) and methods: Twenty-nine patients with MS aged 0 to 4 underwent prospective dental examination as well as early orthodontic treatment. RESULTS: All patients presented micrognathia, lack of lip seal, high arched palate and weak soft palate. The use of orthopedic appliances was recommended to all 29 patients, but only 13 adhered to treatment and were monitored for at least 24 months. We observed that, after 24 months of treatment, the palate was expanded and micrognathia became less severe in the majority of the cases. Pregnancy-related complications were reported by 27 (97%) of the 29 mothers. CONCLUSION(S): The early use of orthopedic appliances was important to prevent malocclusion and glossoptosis. Attempted abortion with misoprostol is associated with an increased risk of MS in infants.

Analysis of epithelial-myoepithelial carcinoma based on the establishment of a novel cell line.

Epithelial-myoepithelial carcinoma of the salivary gland is a rare, low-grade, neoplasm, composed of ductal and myoepithelial cells. We present two novel cell lines, which have been characterised by immunofluorescence, derived from an epithelial-myoepithelial carcinoma of the parotid gland. A resected mass of the parotid gland was diagnosed as an epithelial-myoepithelial carcinoma by routine histological examination. Part of the specimen was labelled with a panel of antibodies confirming the tumour type. The other part was finely minced and the explants were incubated in DMEM supplemented with penicillin and streptomycin, at 37 degrees C in a humidified 5% CO(2) atmosphere. Two cell types were identified by immunofluorescence-a small cobblestone cell, positive for AE1/AE3 and p53, and a polyhedral cell, positive for vimentin, smooth muscle markers and S-100. Herein two cell lines are presented in order to open up possibilities of new studies and a discussion of the events that culminate in this bimodal neoplasm is also performed.

Salivary gland tumours: immunoexpression of integrins beta 1, beta 3 and beta 4.

BACKGROUND: Integrins, heterodimeric transmembranic adhesion molecules composed of alpha and beta subunits, have been implicated in normal and neoplastic biological processes. We investigated the patterns of expression of integrins subunits beta 1, beta 3 and beta 4 in neoplasms derived from the terminal segment of salivary glands in order to understand their expression patterns in the different structures of these tumours. METHODS: Immunohistochemistry using 'catalized signal amplification' (CSA) detection system was applied to paraffin-embedded specimens of polymorphous low-grade adenocarcinoma, adenoid cystic carcinoma and acinic cell carcinoma. Normal salivary glands were used as controls. RESULTS: Immunoexpression of integrins showed that neoplastic structures of the tumours studied tend to mimic the patterns seen in the normal structures of salivary glands from which they are derived. Anaplastic cells were negative for all integrins. CONCLUSIONS: This study revealed detailed topography of integrins in malignant tumours derived from intercalated acinar segment of salivary gland and this might be useful in the diagnosis of these lesions, especially of fine-needle aspiration (FNA) products or small specimens derived form incisional biopsies.

Langerhans cell histiocytosis: recurrent lesions affecting mandible in a 10-year-old patient.

Hand-Schuller-Christian disease is a multifocal variant of eosinophilic granuloma, characterised by the classical triad of bony lesions, exophthalmos and diabetes insipidus. This case relates recurrent Langerhans' cell histiocytosis lesions presented as destruction of periodontal support associated with diabetes in a 10-year-old patient. Medical history suggests that the case represents a case of Hand-Schuller Christian disease.

Paracoccidioidomycosis in an HIV-positive patient: a case report with gingival aspects.

Paracoccidioidomycosis is an important deep mycosis, endemic in some areas of the South American countryside, with great incidence in males bearing rural activities, being unusual in urban developed centres. Cell-mediated immunity is the main host defence against the P. brasiliensis, and HIV-positive patients have been increasingly affected by the disease, although only a few reports are available in the literature. We present a case of paracoccidiodomicosis in an HIV-positive female, with unusual clinical history and histopathological aspects.

Paracoccidioidomycosis in an HIV-positive patient: a case report with gingival aspects / Paracoccidioidomycosis em um paciente HIV-positivo: relato de caso com aspectos gengivais

Paracoccidioidomycosis is an important deep mycosis, endemic in some areas of the South American countryside, with great incidence in males bearing rural activities, being unusual in urban developed centres. Cellmediated immunity is the main host defence against the P. brasiliensis, and HIV-positive patients have been increasingly affected by the disease, although only a few reports are available in the literature. We present a case of paracoccidiodomicosis in an HIV-positive female, with unusual clinical history and histopathological aspects