Advertisement for orthosearch.org.uk
Results 1 - 3 of 3
Results per page:
Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_7 | Pages 7 - 7
1 Apr 2014
Silverwood R Fairhurst P Tsimbouri P Sjostrom T Young P Su B Meek R Dalby M
Full Access

Background

Aseptic loosening remains the primary reason for failure of orthopaedic implants. Therefore a prime focus of Orthopaedic research is to improve osteointegration and outcomes of joint replacements. The topography of a material surface has been shown to alter cell adhesion, proliferation and growth. The use of nanotopography to promote cell adhesion and bone formation is hoped to improve osteointegration and outcomes of implants. We have previously shown that 15nm high features are bioactive. The arrangement of nanofeatures has been shown to be of importance and block-copolymer separation allows nanopillars to be anodised into the titania layer, providing a compromise of control of order and height of nanopillars. Osteoblast/osteoclast stem cell co-cultures are believed to give the most accurate representation of the in vivo environment, allowing assessment of bone remodelling related to biomaterials.

Aims

To assess the use of nanotopography on titania substrates when cultured in a human bone marrow derived co-culture method.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 103 - 103
1 Jul 2014
Avnet S Salerno M Zini N Gibellini D Baldini N
Full Access

Summary

We demonstrate that osteoclast-like cells of GCT result from the spontaneous fusion and differentiation of CD14+ cells of the monoblastic lineage by an autocrine mechanism mediated by RANKL, rather than induced by stromal cells. This process is further enhanced by the simultaneous impairment of the negative feed-back regulation of osteoclastogenesis by interferon β.

Introduction

Giant cell tumor of bone (GCT) is a benign osteolytic lesion with a complex histology, comprising prominent multinucleated osteoclast-like cells (OC), mononuclear stromal cells (SC), and monocyte-like elements. So far, most studies have focused on SC as the truly transformed elements that sustain osteoclast differentiation, while less attention has been paid on the monocyte-like cell fraction. On the contrary, we have previously shown that SC are non-transformed element that can induce osteoclastogenesis of monocytes at levels that do not exceed that of normal mesenchymal stromal cells. We therefore focused on CD14+ monocyte-like cells as an alternative key candidate for the pathogenesis of GCT.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 10 - 10
1 Jul 2014
Kim S Hong J Yoon H Kwon B Lee I Kim H
Full Access

Summary Statement. Obovatol inhibits receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis and prevents inflammatory bone loss in mice. Introduction. Adult skeletal mass and integrity are maintained by balancing osteoclast-mediated bone resorption and osteoblast-induced bone formation during bone remodeling. Abnormal increases in osteoclastic bone resorption can lead to excessive bone destruction as observed in osteoporosis, rheumatoid arthritis, and metastatic cancers Therefore, Modulation of osteoclast formation and function is a promising strategy for the treatment of bone-destructive diseases. To search for compounds that inhibit osteoclast formation, we tested the effect of obovatol, a natural product isolated from the medicinal plant Magnolia obovata, on osteoclastogenesis and inflammatory bone loss. Methods. Osteoclastogenesis was assessed using bone marrow-derived macrophages. RANKL signaling was assessed by immunoblotting and apoptosis by cell death ELISA assay. Actin ring staining and resorption pit assay was performed. Bone morphometric parameters were determined using a microcomputed tomography system. Results. We found that obovatol strongly inhibited osteoclast formation from bone marrow-derived macrophages in a dose-dependent manner without cytotoxicity. Obovatol significantly suppressed RANKL-induced activation of NF-κB, JNK, and ERK signaling pathways. Obovatol also inhibited RANKL-induced expression of the genes c-Fos and nuclear factor of activated T cells c1, which are transcription factors important for osteoclastogenesis. In addition to osteoclast differentiation, obovatol blocked cytoskeletal organization and abrogated the bone resorbing activity of mature osteoclast. Obovatol also accelerated osteoclast apoptosis through the induction of caspase-3 activation. Consistent with its in vitro anti-resorptive effect, obovatol prevented bone loss induced by lipopolysaccharide (LPS) in vivo. Conclusion. Our findings demonstrate that obovatol, a natural compound isolated from Magnolia obovata, suppresses the differentiation, function, and survival of osteoclasts. Furthermore, obovatol protected against LPS-induced bone loss in vivo. Therefore, we suggest that obovatol may have therapeutic potential for the treatment of bone-destructive diseases characterised by increased osteoclast number and/or activity