IADR Abstract Archives
Resolvin E1 inhibits human osteoclast formation and activity in vitro
Objectives: Osteoclasts, derived from monocyte/macrophage cell lineage, are responsible for pathogenic bone loss associated with chronic inflammatory diseases including periodontitis and rheumatoid arthritis. The resolution of inflammation is a regulated process involving pro-resolving lipid mediators including Resolvin E1 (RvE1). However, there are limited studies evaluating the osteoimmunological link between the RvE1 activity and bone metabolism. The aim of the study was to identify the direct actions of RvE1 on bone resorption in vitro using osteoclastic cells derived from human monocyte/macrophages.
Methods: Human peripheral blood mononuclear cells from healthy donors were isolated from whole blood by differential centrifugation. Osteoclast differentiation was induced by treatment with receptor activator of nuclear factor kappa B-ligand (RANKL), from day 7 of the 17-day in vitro assay. Cells were simultaneously treated with the pro-resolving lipid mediator, RvE1 (1, 5, 10ng/ml) to assess its effect on osteoclastogenesis. Osteoclast formation was determined by tartrate-resistant acid phosphatase (TRAP) expression by immunohistochemistry. Osteoclast activity was measured by the quantification of surface resorption on dentine discs, via scanning electron microscopy. Gene expression of osteoclast specific factors was determined by real-time polymerase chain reaction.
Results: Formation of osteoclasts was significantly suppressed by 60% (p<0.05) at 10ng/ml RvE1 with reduced numbers of TRAP+ cells forming in vitro compared to control cells. All concentrations of RvE1 statistically decreased osteoclast resorptive activity by almost 50% compared to control cells with the greatest reduction of pit formation at 10ng/ml RvE1 by 60% (p<0.05).
Conclusions: The results suggest a direct role for RvE1 in regulating bone resorption and thereby reducing bone loss which is a key feature of chronic inflammatory diseases including periodontitis and rheumatoid arthritis.
Methods: Human peripheral blood mononuclear cells from healthy donors were isolated from whole blood by differential centrifugation. Osteoclast differentiation was induced by treatment with receptor activator of nuclear factor kappa B-ligand (RANKL), from day 7 of the 17-day in vitro assay. Cells were simultaneously treated with the pro-resolving lipid mediator, RvE1 (1, 5, 10ng/ml) to assess its effect on osteoclastogenesis. Osteoclast formation was determined by tartrate-resistant acid phosphatase (TRAP) expression by immunohistochemistry. Osteoclast activity was measured by the quantification of surface resorption on dentine discs, via scanning electron microscopy. Gene expression of osteoclast specific factors was determined by real-time polymerase chain reaction.
Results: Formation of osteoclasts was significantly suppressed by 60% (p<0.05) at 10ng/ml RvE1 with reduced numbers of TRAP+ cells forming in vitro compared to control cells. All concentrations of RvE1 statistically decreased osteoclast resorptive activity by almost 50% compared to control cells with the greatest reduction of pit formation at 10ng/ml RvE1 by 60% (p<0.05).
Conclusions: The results suggest a direct role for RvE1 in regulating bone resorption and thereby reducing bone loss which is a key feature of chronic inflammatory diseases including periodontitis and rheumatoid arthritis.