Behaviour of human dental pulp stem cell in high glucose condition: impact on proliferation and osteogenic differentiation.

OBJECTIVE: The aim of this study is to investigate the changes of human dental pulp stem cell (hDPSC) viability, proliferation and osteogenic differentiation in high glucose condition. DESIGN: After 21 days of culture in low (5.5 mM) and high (20 mM) glucose medium, hDPSC viability and proliferation were assessed with respectively the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Hoechst assays. To investigate the influence of glucose on osteogenic differentiation hDPSCs were cultured for 28 days in low or high glucose medium with osteoinductive cocktail. Mineralization was examined by alizarin red staining/quantification and the expression of osteogenic-related genes [Runt-related transcription factor 2 (RUNX2), Osteocalcin (OCN), Collagen 1A1 (COL1A1)] analyzed by RT-qPCR. RESULTS: We observed no significant difference (p >  0.05) on hDPSC proliferation or cell viability between low or high glucose groups. We did not highlight a significant difference after alizarin red staining and quantification between hDPSCs cultured with high or low glucose concentration in the culture medium. In the same manner, high glucose concentration did not appear to modify osteogenic gene expression: there was no significant difference in osteogenic-related gene expression between high or low glucose groups. CONCLUSION: Proliferation, viability, and osteogenic differentiation of hDPSCs were not changed by high glucose environment.

Brain abscesses and intracranial empyema due to dental pathogens: Case series.

INTRODUCTION: Spontaneous brain abscess and intracranial empyema are rare but life-threatening diseases. They can result from potential complications of oral chronic infections. Given the similarity between most of the germs commonly found both in cerebral abscess and in oral cavity and its anatomic proximity, the oral cavity represents a major source of cerebral infections. PRESENTATION OF CASES: We report here a series of seven cases of intracranial abscesses and empyema due to dental pathogens that occurred in the neurosurgery department of our institute. Five of those seven cases were then cared in the oral surgery department of our institute. DISCUSSION: Bacteriological examination of the brain abscesses identified an oral commensal bacterium belonging to streptococci group in six patients (85.7%) and Porphyromonas Gingivalis, a pathogen oral germ involved in periodontal diseases in the seventh patient. For all patients examined, oral status and oral health were poor or moderate with the presence of dental caries, missing teeth and abundant dental plaque. Except the oral cavity, no other front door or infectious site were found. CONCLUSION: This rare series of cases highlights the importance of systematically explore the oral cavity in presence of intracranial infection and to radically eradicate the potential infectious foci.

Dental Pulp Stem Cell-Derived Conditioned Medium: An Attractive Alternative for Regenerative Therapy.

Mesenchymal stem cells (MSC) have a lot of potential in regenerative medicine, and MSC-based therapies are currently explored in numerous research fields. Among these cells, deciduous or permanent dental pulp-MSC represent a promising option in tissue engineering. This expectation is based on their capacity to self-renew, to repair various damaged tissues and organs due to their multipotency, as well as their ability to modulate immune system. They present other advantages such as the harvesting by a simple, painless, and noninvasive procedure and the absence of ethical considerations. The role played by these cells in the reparative process is mainly attributed to paracrine mechanisms mediated by their secreted factors, namely the secretome. The secreted factors can be found in the cell culture medium, called conditioned medium (CM). Moreover, CM presents many advantages compared with cells such as possible use in allogeneic therapies. This minireview aims at investigating the therapeutic use of dental pulp MSC-derived CM to develop cell-free therapies. The analysis of the available literature illustrates its massive panel of potential applications: mainly reduction of inflammation, promotion of angiogenesis and neurogenesis, reduction of stroke or ischemia, and organ regeneration. Furthermore, studies often highlight its superiority over the other sources of CM derived from other stem cells for the same applications. Dental pulp MSC-derived CM is an attractive, noninvasive, and acellular tool for therapeutic approaches in regenerative medicine. This promising novel approach should be further explored for clinical applications.