Felice Roberto Grassi

Lymphocytes and synovial fluid fibroblasts support osteoclastogenesis through RANKL, TNFα, and IL‐7 in an in vitro model derived from human psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory joint disease, characterized by extensive bone resorption, whose mechanisms have not been fully elucidated. Thus, in the present study we investigated the involvement of RANKL, TNFα, and IL‐7 in the osteoclastogenesis of PsA patients. In vitro osteoclastogenesis models, consisting of unfractionated and T‐cell‐depleted mononuclear cells from peripheral blood (PBMCs) and synovial fluid (SFMCs) of 20 PsA patients as well as from healthy donors were studied. Freshly isolated T and B cells from PBMCs and T cells and fibroblasts from SFMCs of PsA patients were subjected to RT‐PCR to detect the levels of RANKL, TNFα, and IL‐7. Osteoclastogenesis was studied in the presence of RANK‐Fc, anti‐TNFα, and anti IL‐7 functional antibodies. We demonstrate that lymphocytes and fibroblasts support osteoclast (OC) formation in PsA patients through the production of osteoclastogenic cytokines. In particular, OC formation was completely abolished in unstimulated T cell‐depleted PBMC cultures, and reduced by approximately 70% in unstimulated T cell‐depleted SFMC cultures. Freshly isolated T cells from PBMCs and SFMCs of PsA patients overexpressed RANKL and TNFα, while fibroblasts from synovial fluid produced only RANKL. We show that the presence of RANK‐Fc and/or anti‐TNFα functional antibodies reduced OC formation. Moreover, T and B cells from PBMCs as well as T cells and fibroblasts from SFMCs expressed IL‐7 mRNA. Finally, the anti‐IL‐7 functional antibody significantly reduced osteoclastogenesis. Our results suggest that fibroblasts, B and T lymphocytes support OC formation by producing RANKL, TNFα, and IL‐7, contributing to the aggressive bone resorption in PsA patients. Copyright

Dental pulp stem cells: osteogenic differentiation and gene expression.

Dental pulp stem cells (DPSCs) are an adult stem cell population with high proliferative potential and the ability to differentiate in many cell types, and this has led scientists to consider these cells to be an alternative source of postnatal stem cells comparable to mesenchymal stem cells from bone marrow. In this work, we studied the osteoblastic phenotype developed by DPSCs cultured in osteogenic medium. In particular, we analyzed the expression of the typical osteoblast markers such as alkaline phosphatase, collagen type I, osteocalcin, osteopontin, as well as mineralized matrix production. Furthermore, the gene expression during DPSC differentiation into osteoblastic cells was studied by microarray technology. Using microarray and reverse transcriptase–polymerase chain reaction (RT‐PCR) analysis, we found that IGFBP‐5, JunB, and NURR1 genes are upregulated during the differentiation of DPSCs. These data indicate that opportunely differentiated DPSCs show a correct osteoblastic phenotype. Therefore, during the osteoblastic differentiation process, IGFBP‐5, JunB, and NURR1 gene expression is significantly increased.

The death receptor DR5 is involved in TRAIL-mediated human osteoclast apoptosis

The number and activity of osteoclasts (OCs) are critical for maintaining normal bone turnover. The number is determined by the rates of cell differentiation and death. TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, induces apoptosis by interacting with its death receptors, (DR4, DR5). However, its activity can be modulated by two decoy receptors, (DcR1 and DcR2). In this paper we show that TRAIL treatment causes reduced OC viability as well as an increased apoptotic OC number. Loss of nuclei integrity and derangement of the actin microfilament were also induced by TRAIL in OCs. Moreover, we demonstrated the expression of all TRAIL receptors in both precursors and differentiated OCs, and the upregulation of DR5 during OC differentiation. Interestingly, DcR2 was upregulated in the early stage of osteoclastogenesis and downregulated at the end of the differentiation process. We showed that DR5, upregulated by TRAIL, could be the mediator of TRAIL-induced OC apoptosis, since the addition of anti-DR5 neutralizing antibodies restores the OC viability previously reduced by TRAIL. Furthermore, the intracellular pathway induced by TRAIL in OCs involves caspase-8 and Bid activation. In conclusion, our data highlight an important role for the TRAIL/TRAIL receptor system in the regulation of OC apoptosis.

In Vitro Stem Cell Cultures from Human Dental Pulp and Periodontal Ligament: New Prospects in Dentistry:

In spite of the vast knowledge of tooth development and of the various kinds of specialized bone/tooth-associated cells, the characteristics and properties of their precursor cell populations present in the postnatal organism are little known, as is their possible therapeutic use. Taken together dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) possess stem-cell-like qualities, including self-renewal capability and multi-lineage differentiation. Regenerative medicine is based on stem cells, signals and scaffolds. Transplantation of those cells, which can be obtained from an easily accessible tissue resource and expanded in vitro, holds promise as a therapeutic approach for reconstruction of tissues and bone in vivo.

Immediate transmucosal implant placement in molar extraction sites: a 12‐month prospective multicenter cohort study

AIM To assess the clinical and radiographic outcomes of immediate transmucosal placement of implants into molar extraction sockets. STUDY DESIGN Twelve-month multicenter prospective cohort study. MATERIAL AND METHODS Following molar extraction, tapered implants with an endosseous diameter of 4.8 mm and a shoulder diameter of 6.5 mm were immediately placed into the sockets. Molars with evidence of acute periapical pathology were excluded. After implant placement and achievement of primary stability, flaps were repositioned and sutured allowing a non-submerged, transmucosal healing. Peri-implant marginal defects were treated according to the principles of guided bone regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresrobable collagen membrane. Standardized radiographs were obtained at baseline and 12 months thereafter. Changes in depth and width of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD) were assessed. RESULTS Eighty-two patients (42 males and 40 females) were enrolled and followed for 12 months. They contributed with 82 tapered implants. Extraction sites displayed sufficient residual bone volume to allow primary stability of all implants. Sixty-four percent of the implants were placed in the areas of 36 and 46. GBR was used in conjunction with the placement of all implants. No post-surgical complications were observed. All implants healed uneventfully yielding a survival rate of 100% and healthy soft tissue conditions after 12 months. Radiographically, statistically significant changes (P<0.0001) in mesial and distal crestal bone levels were observed from baseline to the 12-month follow-up. CONCLUSIONS The findings of this 12-month prospective cohort study showed that immediate transmucosal implant placement represented a predictable treatment option for the replacement of mandibular and maxillary molars lost due to reasons other than periodontitis including vertical root fractures, endodontic failures and caries.

Osteogenic differentiation of dental follicle stem cells.

Background: Stem cells are defined as clonogenic cells capable of self-renewal and multi-lineage differentiation. A population of these cells has been identified in human Dental Follicle (DF). Dental Follicle Stem Cells (DFSCs) were found in pediatric unerupted wisdom teeth and have been shown to differentiate, under particular conditions, into various cell types of the mesenchymal tissues. Aim: The aim of this study was to investigate if cells isolated from DF show stem features, differentiate toward osteoblastic phenotype and express osteoblastic markers. Methods: We studied the immunophenotype of DFSCs by flow cytometric analysis, the osteoblastic markers of differentiated DFSCs were assayed by histochemical methods and real-time PCR. Results: We demonstrated that DFSCs expressed a heterogeneous assortment of makers associated with stemness. Moreover DFSCs differentiated into osteoblast-like cells, producing mineralized matrix nodules and expressed the typical osteoblastic markers, Alkaline Phosphatase (ALP) and Collagen I (Coll I). Conclusion: This study suggests that DFSCs may provide a cell source for tissue engineering of bone.

Osteogenic differentiation of mesenchymal stem cells from dental bud: Role of integrins and cadherins

Several studies have reported the beneficial effects of mesenchymal stem cells (MSCs) in tissue repair and regeneration. New sources of stem cells in adult organisms are continuously emerging; dental tissues have been identified as a source of postnatal MSCs. Dental bud is the immature precursor of the tooth, is easy to access and we show in this study that it can yield a high number of cells with ≥95% expression of mesenchymal stemness makers and osteogenic capacity. Thus, these cells can be defined as Dental Bud Stem Cells (DBSCs) representing a promising source for bone regeneration of stomatognathic as well as other systems. Cell interactions with the extracellular matrix (ECM) and neighboring cells are critical for tissue morphogenesis and architecture; such interactions are mediated by integrins and cadherins respectively. We characterized DBSCs for the expression of these adhesion receptors and examined their pattern during osteogenic differentiation. Our data indicate that N-cadherin and cadherin-11 were expressed in undifferentiated DBSCs and their expression underwent changes during the osteogenic process (decreasing and increasing respectively), while expression of E-cadherin and P-cadherin was very low in DBSCs and did not change during the differentiation steps. Such expression pattern reflected the mesenchymal origin of DBSCs and confirmed their osteoblast-like features. On the other hand, osteogenic stimulation induced the upregulation of single subunits, αV, β3, α5, and the formation of integrin receptors α5β1 and αVβ3. DBSCs differentiation toward osteoblastic lineage was enhanced when cells were grown on fibronectin (FN), vitronectin (VTN), and osteopontin (OPN), ECM glycoproteins which contain an integrin-binding sequence, the RGD motif. In addition we established that integrin αVβ3 plays a crucial role during the commitment of MSCs to osteoblast lineage, whereas integrin α5β1 seems to be dispensable. These data suggest that functionalization of biomaterials with such ECM proteins would improve bone reconstruction therapies starting from dental stem cells.

Use of Lugol’s iodine in oral cancer diagnosis: An overview

Early diagnosis of oral squamous cell carcinoma (OSCC) still represents an important challenge for clinicians and patients. Vital staining such as toluidine blue and Lugols iodine solution, are routinely used in the OSCC detection but few data exist about the last one. A literature review is made to evaluate the effectiveness and safety of Lugols iodine solution in OSCC detection and in its margins demarcation. A review was made of the studies published between 1990 and 2010 in relation to the application of Lugols iodine for OSCC detection and a better definition of its margins. Data obtained point to the utility and the safety of Lugols iodine when employed for detection and margins delineation of OSCC and dysplasia. All the studies consulted found the Lugols iodine to be effective, cheap and easy to use and they emphasized its importance in clinical practice. There is need for larger controlled, randomized studies with carefully selected and standardized outcome measures and patients.

Transmission of Nonviral Sexually Transmitted Infections and Oral Sex

INTRODUCTION Oral sex is usually considered a lower-risk sexual activity when compared with sex, but it is frequently the cause of sexually transmitted infections (STI). In particular, STI transferred through oral sex might have no visible symptoms, depending on the type of infection. AIMS The aim of this study is to review the literature about the role of oral sex in the transmission of nonviral STI. MAIN OUTCOME MEASURES State-of-the-art information in the area of STI in relation to sexual function and self-care, this last important for development of STI prevention products such as vaginal microbicides. Sexual behaviors assessed focusing on receiving oral sex and giving oral sex. METHODS A search of the main electronic databases including registers of clinical controlled trials was performed in addition to a hand search of the most relevant Journals. The following electronic databases were searched: PubMed, Embase, Google Scholar, literature review of research articles, and public health department Internet Web sites, for the period of 1945-2011. In addition to searching the Clinical Trials Registry at the US National Institutes of Health, we also used the meta Register of Controlled Trials and the Cochrane Central Register of Controlled Trials. RESULTS STI affect the mucous membranes both directly and indirectly producing characteristic diagnostic signs and lesions. Daily dental clinical activity needs an appropriate knowledge of any kind of oral lesions-related STI. The reader is offered a practical approach with clinically relevant recommendations that may prove useful in his/her daily practice when dealing with STI. CONCLUSIONS These data provide a foundation for understanding diverse STI. We advise physicians to be receptive to discuss sexuality issues and provide patients with adequate therapy.

TRAIL Is Involved in Human Osteoclast Apoptosis

Abstract:  Control of osteoclast (OC) apoptosis has been recognized as a critical regulatory factor in bone remodeling. TRAIL, a member of the TNF superfamily, induces apoptosis in neoplastic and normal cells. However, few data are available on the effects of TRAIL on bone cells, thus in the present study we investigated TRAIL role on the apoptosis of human mature OCs. We show that TRAIL treatment causes reduced cell viability, loss of nuclei integrity, and derangement of the actin microfilament in OCs. We also demonstrated that the death receptor DR5, upregulated by TRAIL, could be the mediator of TRAIL‐induced OC apoptosis.