Resumen de Porphyromonas gingivalis Lipopolysaccharide Stimulation of Vascular Smooth Muscle Cells Activates Proliferation and Calcification
Guirong Liu, Jing Deng, Fu-Qiang Zhang, Wenbin Song, Shulan Chen, Xiuxiu Lou, Pengmei Zhang, Keqing Pan
Background: Porphyromonas gingivalis (Pg) is a major etiologic agent of periodontitis, whose virulence has been attributed to different factors, including lipopolysaccharide (LPS).
Vascular ectopic calcification as a well-known major risk factor for adverse cardiovascular diseases is a highly prevalent vascular pathophenotype, and vascular smooth muscle cells (VSMCs) play an important role in mediating vascular calcification.
It was hypothesized that Pg-LPS may stimulate vascular calcification through a direct effect on VSMC function. To test this hypothesis, the effect of Pg-LPS on VSMC calcification was determined.
Methods: Primary cultures of VSMCs were obtained and identified by immunochemistry in vitro. The proliferation and alkaline phosphatase (ALP) activity of VSMCs were measured using a cell counting kit and an ALP activity test. Mineral deposition was examined using alizarin red staining. Gene (e.g.
ALP, core binding factor a1 [Cbfa1], bone sialoprotein [BSP], and osteopontin [OPN]) expression levels altered by Pg-LPS were determined by reverse transcription-polymerase chain reaction array.
Results: Pg-LPS could increase the proliferation of VSMCs at different times and enhance ALP activity of VSMCs after 1 day. Alizarin red staining and quantification showed that, with Pg-LPS treatment, VSMCs displayed more obvious calcifi- cation nodules. When stimulated with Pg-LPS, the expression of specific osteogenic genes (e.g., ALP, Cbfa1, BSP, and OPN) was significantly promoted in the presence or absence of mineralization-inducing medium, whereas the expression of the OPN gene was inhibited in the mineralization induction group at day 7.
Conclusion: Pg-LPS can stimulate VSMC calcification, which results in vascular calcification, further proving the precise relationship between periodontitis and vascular calcification.
J Periodontol 2016;87:828-836.
