Dental Pulp and Periodontal Ligament Cells Support Osteoclastic Differentiation

Abstract

Odontoclasts and cementoclasts are considered to play major roles in the internal resorption of dentin and the external resorption of tooth roots. In this study, we evaluated the osteoclast-inducing ability of human dental pulp and periodontal ligament cells, which are mesenchymal cells in dental tissues. These cells expressed RANKL and OPG mRNA constitutively. As osteoclast precursors, CD14(+) monocytes derived from human peripheral blood were isolated, and incubated together with human dental pulp or periodontal ligament cells. Both cell types spontaneously induced the differentiation of CD14(+) monocytes into osteoclasts without osteotropic factors. These results suggest that dental pulp and periodontal ligament cells are involved in regulating the differentiation and function of osteoclasts.

Oral biofilm challenge regulates the RANKL-OPG system in periodontal ligament and dental pulp cells

“…Both the PDL and DP contain mesenchymal cells that express RANKL and OPG and can support osteoclastogenesis [14]. The balanced expression of these factors is decisive for the regulation of bone resorption by DP cells [15] or PDL cells [16].…”

Uremia Induces Dental Pulp Ossification but Reciprocally Inhibits Adjacent Alveolar Bone Osteogenesis

“…In chronic dialysis patients, circulating OPG increases to reduce bone resorption, which acts as a protective mechanism in response to low bone mineral density (BMD) [2,30]. Furthermore, an in vitro study showed that cultured dental pulp cells express strong OPG and suppress osteoclasts, suggesting that pulp OPG suppresses tooth resorption [49], which may then lead to pulp osteogenesis. In uremic pulp, we found that pulp mineralization remained significantly increased when the OPG expression was low, indicating that a relatively low level of pulp OPG may act as a compensatory response against the osteogenic process of uremic pulp.…”

Localización de OPG en la Pulpa Dental del Ratón Albino Suizo

“…Estos hallazgos se encuentran en concordancia con los estudios in vitro presentados por Rani & MacDougall y Sakata et al, quienes describieron la habilidad de expresar mRNA de OPG por parte de las células dentales de origen mesenquimal y no por parte de las epiteliales. Uchiyama et al (2009), encontraron que la expresión de OPG yRANKL por parte de las células pulpares y del ligamento periodontal permite soportar la diferenciación y mantenimiento de osteoclastos in vitro.…”