Expression profiles of TGF-ß and TLR pathways in Porphyromonas gingivalis and Prevotella intermedia challenged osteoblasts

Although many microorganisms have been related to loss of bone in dental implant failures, it is still unknown as to which of these pathogens play a role in bone loss following dental implant surgery. As the long term survival of dental implants depends in part, on the control of bacterial infection, the presence of these oral pathogens in and around the failing implant site activates an immune response in the human body. Interaction between bacteria and host cells invariably results in the release of one or more cytokines. This study is focused on determination of the effects of oral pathogens known to be isolated from around the failing implant site on viability, matrix mineralization and the expression pattern of proinflammatory mediators and other cytokine receptors of bone cells For this purpose osteoblasts were challenged by Porphyromonas gingivalis and Prevotella intermedia, one of the most predominantly isolated bacteria, from dental implant failures. Results showed that these challenges reducing viability and matrix mineralization of osteoblasts. These pathogens affect osteoblast viability in a dose dependent manner. In addition QRT-PCR results of TGF-ß and TLR showed that these pathogens affect the expressions of TGF-ß pathway cytokine and receptors in a different direction however TLR pathway genes were affected in the same direction. BMPER and BMPR1B are the receptors of TGF-ß pathway that were found to be upregulated by P.g and P.i challenge. In the TLR pathway highly expressed genes were found to be IL8 and NFRKB. These findings indicate that the presence of both P. gingivalis and P. intermedia may inhibit osseointegration and induce bone resorption. In the light of this knowledge we can conclude that P.gingivalis and P.intermedia are both risk factors for dental implant failure.