RESUMO
The objective of this study was to compare the osteogenic potential of human embryonic stem cells (hESCs) within two- and three-dimensional (2D and 3D) culture systems. hESCs of the H1 line (Wicell Inc., Madison, Wisc., USA) were induced to form embryoid bodies (EBs) through 5 days of suspension culture within non-adherent culture dishes. Following enzymatic dissociation, the EB-derived single cells were seeded on either novel 3D porous PLGA scaffolds or 2D culture dishes with the same total cell number. Osteogenic differentiation was induced through culture media supplemented with dexamethasone, L-ascorbic acid and beta-glycerophosphate. After 3 weeks of in vitro culture, quantitative and qualitative assays of osteogenic differentiation were conducted. Osteocalcin secretion and alkaline phosphatase (AP) activities were detected at significantly higher levels within 3D culture compared with the 2D system. Subsequently, the cell-scaffold constructs were implanted in iliac crest defects of immunosuppressed rabbits. After 4 weeks, the constructs were subsequently explanted and characterized by histology and X-ray analysis. Formation of new bone was detected within and around the implanted scaffolds. The results demonstrate that the osteogenic differentiation of human embryonic stem cells is enhanced in a 3D culture system compared to a 2D culture environment. Upon implantation in situ, the differentiating human embryonic stem cells can contribute positively to the repair and regeneration of bone defects.
Assuntos
Células-Tronco Embrionárias/citologia , Osteogênese/fisiologia , Engenharia Tecidual/métodos , Fosfatase Alcalina/metabolismo , Animais , Antígenos de Superfície/metabolismo , Ácido Ascórbico/farmacologia , Regeneração Óssea , Calcificação Fisiológica/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Dexametasona/farmacologia , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , Glicerofosfatos/farmacologia , Humanos , Ílio/patologia , Ílio/cirurgia , Implantes Experimentais , Ácido Láctico/química , Masculino , Microscopia Confocal , Fator 1 de Transcrição de Octâmero/metabolismo , Osteocalcina/metabolismo , Osteogênese/efeitos dos fármacos , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros/química , Coelhos , Técnicas de Cultura de Tecidos/métodos , Alicerces Teciduais/químicaRESUMO
Among the various traditional beliefs and practices of the peoples of the Southeast Asia region is the practice of inserting talismans under the skin in various parts of the human body. In the orofacial region, these talismans (also called charm needles or charm pins) are also seen, usually as incidental radiographic findings. These talismans are believed to enhance the beauty of the wearers, as well as to provide protection to the wearers against harm. It is also believed that they could help the wearer obtain favorable business deals inasmuch as they are believed to have a "spell-like" influence on the business counterparts. In the present series, 67% of the patients are female and 66% of them are Muslim. Very little is known about the possible ill effects of these talismans because there is no report of these radiographic findings in major dental journals. In the present series of 12 cases representing a total of 65 talismans, only one talisman was surgically removed. We believe that generally no definitive treatment is required. However, we believe that the existence of these talismans should be made known so that they will not be misdiagnosed and mismanaged.