Valproic Acid Modulates the Multipotency in Periodontal Ligament Stem Cells via p53-Mediated Cell Cycle

Human periodontal ligament stem cells (PDLSCs), a type of mesenchymal stem cell, are a promising source for dental regeneration and are identified in human periodontal ligaments from extracted third molars. Valproic acid (VPA) is a histone deacetylase inhibitor that has been used as a wide-spectrum antiepileptic drug and a medication for mood disorders. VPA has shown several effects on increasing the pluripotency of embryonic stem cells and controlling osteogenic differentiation, besides the prevention of seizures. However, its effect on proliferation and osteogenesis depends on the cell type and concentration. The aim of this study was to investigate the effects of cyclic and constant VPA treatment on PDLSCs. Proliferation and apoptosis of PDLSCs were determined with cyclic and constant VPA treatment. In cemento/ osteogenic differentiation, osteogenic markers decreased significantly after cyclic treatment with 0.5 mM VPA. In contrast, VPA enhanced osteogenic differentiation after constant treatment. With cyclic VPA treatment, p53 levels related to apoptotic pathway decreased to induce proliferation. These findings indicated that VPA has different roles in proliferation and differentiation of PDLSCs in vitro and in vivo via p53-related pathway.

Modified Fisher method for unilateral cleft lip-report of cases / 대한악안면성형재건외과학회지

BACKGROUND: Rehabilitation of normal function and form is essential in cleft lip repair. In 2005, Dr. David M. Fisher introduced an innovative method, named “an anatomical subunit approximation technique” in unilateral cleft lip repair. According to this method, circumferential incision along the columella on cleft side of the medial flap is continued to the planned top of the Cupid's bow in straight manner, which runs parallel to the unaffected philtral ridge. Usually, small inlet incision is needed to lengthen the medial flap. On lateral flap, small triangle just above the cutaneous roll is used to prevent unesthetic shortening of upper lip. This allows better continuity of the Cupid’s bow and ideal distribution of tension. CASE PRESENTATION: As a modification to original method, orbicularis oris muscle overlapping suture is applied to make the elevated philtral ridge. Concomitant primary rhinoplasty also results in good esthetic outcome with symmetric nostrils and correction of alar web. As satisfactory results were obtained in three incomplete and one complete unilateral cleft lip patients, indicating Fisher’s method can be useful in cleft lip surgery with functional and esthetic outcome. CONCLUSIONS: Clinically applied Fisher's method in unilateral cleft lip patients proved the effectiveness in improving the esthetic results with good symmetry. This method also applied with primary rhinoplasty.

Neurogenic differentiation of human dental stem cells in vitro

OBJECTIVES: The purpose of this study was to investigate the neurogenic differentiation of human dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), and stem cells from apical papilla (SCAP). MATERIALS AND METHODS: After induction of neurogenic differentiation using commercial differentiation medium, expression levels of neural markers, microtubule-associated protein 2 (MAP2), class III beta-tubulin, and glial fibrillary acidic protein (GFAP) were identified using reverse transcriptase polymerase chain reaction (PCR), real-time PCR, and immunocytochemistry. RESULTS: The induced cells showed neuron-like morphologies, similar to axons, dendrites, and perikaryons, which are composed of neurons in DPSCs, PDLSCs, and SCAP. The mRNA levels of neuronal markers tended to increase in differentiated cells. The expression of MAP2 and beta-tubulin III also increased at the protein level in differentiation groups, even though GFAP was not detected via immunocytochemistry. CONCLUSION: Human dental stem cells including DPSCs, PDLSCs, and SCAP may have neurogenic differentiation capability in vitro. The presented data support the use of human dental stem cells as a possible alternative source of stem cells for therapeutic utility in the treatment of neurological diseases.