Impact of Bone Morphogenetic Protein 7 and Prostaglandin receptors on osteoblast healing and organization of collagen.

PURPOSE: This study seeks to investigate the impact of co-administering either a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist alone with a low dose BMP7 on in vitro healing process, collagen content and maturation of human osteoblasts. METHODOLOGY: Human osteoblast cells were used in this study. These cells were cultured and subjected to different concentrations of Prostaglandin EP2 receptor agonist, EP1 receptor antagonist, BMP7, Control (Ct) (Vehicle alone), and various combinations treatments. Cell viability at 24, 48 and 72 hours (h) was evaluated using the XTT assay. A wound healing assay was conducted to observe the migration ability of human osteoblast cells. Additionally, Sirius red staining and Fourier-Transform Infrared Spectroscopy Imaging (FT-IR) was employed to analyze various parameters, including total protein concentration, collagen production, mature collagen concentration, and mineral content. RESULTS: The combination of low dose BMP7 and Prostaglandin EP2 receptor agonist resulted to the lowest cell viability when compared to both the Ct and individual treatments. In contrast, the Prostaglandin EP1 receptor antagonist alone showed the highest cellular viability at 72 h. In the wound healing assay, the combined treatment of low dose BMP7 with the Prostaglandin EP2 receptor agonist and EP1 receptor antagonist showed a decrease in human osteoblast healing after 24 h. Analysis of FT-IR data indicated a reduction in total protein content, collagen maturity, collagen concentration and mineral content in combination treatment compared to the single or Ct treatments. CONCLUSION: The combination of a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist when combined with low dose BMP7 significantly hinders both human osteoblast healing and collagen maturity/concentration in comparison to low dose BMP7 treatment alone.

Molecular pathogenicity of 1-nonadecene and L-lactic acid, unique metabolites in radicular cysts and periapical granulomas.

Recently, 1-nonadecene and L-lactic acid were identified as unique metabolites in radicular cysts and periapical granuloma, respectively. However, the biological roles of these metabolites were unknown. Therefore, we aimed to investigate the inflammatory and mesenchymal-epithelial transition (MET) effects of 1-nonadecene, and the inflammatory and collagen precipitation effects of L-lactic acid on both periodontal ligament fibroblasts (PdLFs) and peripheral blood mononuclear cells (PBMCs). PdLFs and PBMCs were treated with 1-nonadecene and L-lactic acid. Cytokines' expression was measured using quantitative real-time polymerase chain reaction (qRT-PCR). E-cadherin, N-cadherin, and macrophage polarization markers were measured using flow cytometry. The collagen, matrix metalloproteinase (MMP)-1, and released cytokines were measured using collagen assay, western blot, and Luminex assay, respectively. In PdLFs, 1-nonadecene enhances inflammation through the upregulation of some inflammatory cytokines including IL-1ß, IL-6, IL-12A, monocyte chemoattractant protein (MCP)-1, and platelet-derived growth factor (PDGF) α. 1-Nonadecene also induced MET through the upregulation of E-cadherin and the downregulation of N-cadherin in PdLFs. 1-Nonadecene polarized macrophages to a pro-inflammatory phenotype and suppressed their cytokines' release. L-lactic acid exerted a differential impact on the inflammation and proliferation markers. Intriguingly, L-lactic acid induced fibrosis-like effects by enhancing collagen synthesis, while inhibiting MMP-1 release in PdLFs. These results provide a deeper understanding of 1-nonadecene and L-lactic acid's roles in modulating the microenvironment of the periapical area. Consequently, further clinical investigation can be employed for target therapy.

The Essential Role of 17-Octadecynoic Acid in the Pathogenesis of Periapical Abscesses.

INTRODUCTION: Periapical abscesses are 1 of the most frequent pathologic lesions in the alveolar bone. Recently, we have identified 17-octadecynoic acid (17-ODYA) as the highest unique metabolite in periapical abscesses. Therefore, the aim of this study was to investigate the immunologic and pathophysiological roles of this metabolite in the initiation and development of periapical abscesses. METHODS: Periodontal ligament fibroblasts and peripheral blood mononuclear cells were treated with 17-ODYA. Gene expression analysis and interleukin (IL)-8 release were determined using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Macrophage polarization and cytokine release were also determined using flow cytometry and Luminex bioassay (R&D Systems, Minneapolis, MN), respectively. RESULTS: In periodontal ligament fibroblasts, 17-ODYA caused significant (P < .0001) up-regulation of IL-1α, IL-1ß, IL-6, matrix metalloproteinase-1, and monocyte chemoattractant protein-1 at 10 µmol/L after 6 days of treatment and up-regulation of platelet-derived growth factor alpha and vascular endothelial growth factor alpha at all tested concentrations after 2 days of treatment. In peripheral blood mononuclear cells, 17-ODYA significantly increased the expression of IL-1α, IL-1ß, IL-6, matrix metalloproteinase-1, and monocyte chemoattractant protein-1 at 10 µmol/L (P < .0001) and vascular endothelial growth factor alpha and platelet-derived growth factor alpha at 1 µmol/L 17-ODYA (P < .0001). 17-ODYA polarized macrophages toward a proinflammatory phenotype (M1) and suppressed the release of pro- and anti-inflammatory cytokines. 17-ODYA significantly enhanced the release of IL-8. CONCLUSIONS: This study was the first to identify the pathologic role of 17-ODYA in the development of periapical abscesses. The results of this study are important in shedding light on the pathogenesis of periapical abscesses in relation to microbial metabolites.