Browsing by Subject "Osteogenesis"

Now showing 1 - 3 of 3
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    The development of bone changes induced in rats by recombinant human granulocyte colonystimulating factor is suppressed by bisphosphonate
    (Murcia : F. Hernández, 1999) Suzuki, M.; Adachi, K.; Sugimoto, T.; Nakayama, Hiroyuki; Doi, K.
    We have previously demonstrated that high doses of recombinant human granulocyte colonystimulating factor (rhG-CSF) induce bone changes characterized by osteoclastic bone resorption and osteogenesis due to intramembranous ossification in rats. In this communication we examined the effects of a pretreatment with 3-amino-l-hydroxypropylidene-1,lbisphosphonate (AHPrBP), which is a powerful inhibitor of osteoclastic bone resorption, on bone changes induced by rhG-CSF in order to investigate the relation between osteoclastic bone resorption and osteogenesis. AHPrBP (5 mg/kg/day) was subcutaneously given to 6-week-old rats for 2 days. From the following day of the final injection of AHPrBP, rats received a subcutaneous injection of rhG-CSF (1,000 pg/kg/day) for 14 days, and the femur and tibia were evaluated histopathologically. By the analysis of peripheral blood leukocyte counts, spleen weights and bone marrow findings, the pretreatment with AHPrBP had no effect on the activation of hematopoiesis related to the major pharmacological activity of rhG-CSF. In the rats treated with rhG-CSF alone, accelerated osteoclastic bone resorption and osteogenesis due to intramernbranous ossification were observed in the trabeculae of metaphyseal spongiosa. The accelerated osteoclastic bone resorption induced by rhG-CSF was suppressed by the pharmacological activity of AHPrBP. Furthermore, the osteogenesis induced by rhG-CSF was also suppressed by AHPrBP. These results suggest that the osteogenesis induced by rhG-CSF is a sequential reaction of accelerated osteoclastic bone resorption, and moreover that the main action of rhG-CSF on bone is an acceleration of osteoclastic bone resorption.
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    Regulation of human cranial osteoblast phenotype by FGF-2, FGFR-2 and BMP-2 signaling
    (Murcia : F. Hernández, 2002) Marie, P.J.; Debiais, F.; Haÿ, E.
    The formation of cranial bone requires the differentiation of osteoblasts from undifferentiated mesenchymal cells. The balance between osteoblast recruitment, proliferation, differentiation and apoptosis in sutures between cranial bones is essential for calvarial bone formation. The mechanisms that control human osteoblasts during normal calvarial bone formation and premature suture ossification (craniosynostosis) begin to be understood. Our studies of the human calvaria osteoblast phenotype and calvarial bone formation showed that premature fusion of the sutures in nonsyndromic and syndromic (Apert syndrome) craniosynostoses results from precocious osteoblast differentiation. We showed that Fibroblast Growth Factor-2 (FGF-2), FGF receptor-2 (FGFR-2) and Bone Morphogenetic Protein-2 (BMP-2), three essential factors involved in skeletal development, regulate the proliferation, differentiation and apoptosis in human calvaria osteoblasts. Mechanisms that induce the differentiated osteoblast phenotype have also been identified in human calvaria osteoblasts. We demonstrated the implication of molecules (N-cadherin, Il-1) and signaling pathways (src, PKC) by which these local factors modulate human calvaria osteoblast differentiation and apoptosis. The identification of these essential signaling molecules provides new insights into the pathways controlling the differentiated osteoblast phenotype, and leads to a more comprehensive view in the mechanisms that control normal and premature cranial ossification in humans.
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    Wnt signaling in physiological and pathological bone formation
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Tan, Zhenya; Ding, Na; Lu, Haimei; Kessler, John A.; Kan, Lixin
    Wnt signaling, canonical or non-canonical, plays conserved roles in numerous physiological and pathological processes. However, it is well beyond the scope of this review to cover all functional aspects of Wnt signaling in different contexts at reasonable depth; therefore this review intends to cover only the roles of Wnt signaling in bone biology; more specifically, we intend to first update the roles of Wnt signaling in physiological bone process, including in osteogenesis and chondrogenesis, since recent years have witnessed tremendous progressions in this area, and then we seek to extend our understanding to the pathological bone process, especially to the heterotopic ossification (HO), even though the understanding of Wnt signaling in HO has been limited. We then further clarify the potential crosstalking between Wnt and other conserved signaling pathways, including FGF, GPCR and Hif1α pathways. Overall, our goal is to update the progressions, identify the general theme and the knowledge gaps and discuss the potential promising avenue for future applications in HO prevention and treatment.