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The Bone & Joint Journal
Vol. 97-B, Issue 8 | Pages 1144 - 1151
1 Aug 2015
Waki T Lee SY Niikura T Iwakura T Dogaki Y Okumachi E Kuroda R Kurosaka M

MicroRNAs (miRNAs ) are small non-coding RNAs that regulate gene expression. We hypothesised that the functions of certain miRNAs and changes to their patterns of expression may be crucial in the pathogenesis of nonunion. Healing fractures and atrophic nonunions produced by periosteal cauterisation were created in the femora of 94 rats, with 1:1 group allocation. At post-fracture days three, seven, ten, 14, 21 and 28, miRNAs were extracted from the newly generated tissue at the fracture site. Microarray and real-time polymerase chain reaction (PCR) analyses of day 14 samples revealed that five miRNAs, miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p, were highly upregulated in nonunion. Real-time PCR analysis further revealed that, in nonunion, the expression levels of all five of these miRNAs peaked on day 14 and declined thereafter.

Our results suggest that miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p may play an important role in the development of nonunion. These findings add to the understanding of the molecular mechanism for nonunion formation and may lead to the development of novel therapeutic strategies for its treatment.

Cite this article: Bone Joint J 2015; 97-B:1144–51.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_16 | Pages 23 - 23
1 Apr 2013
Kawakami Y Ii M Kawamoto A Matsumoto T Mifune Y Shoji T Fukui T Kuroda R Kurosaka M Asahara T
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Introduction

Failures in fracture healing are mainly caused by a lack of neovascularization. We have previously demonstrated that G-CSF-mobilized peripheral blood (GM-PB) CD34+ cells, an endothelial progenitor enriched cell population, contributed to fracture healing via vasculogenesis and osteogenesis. We postulated the hypothesis that local transplantation of culture expanded bone marrow (cEx-BM) CD34+ cells could exhibit therapeutic potential for fracture healing.

Materials

BM CD34+ cells were cultured in specific medium with 5 growth factors for 1week. A reproducible model of femoral fracture was created in nude rats with periosteum cauterization, which leads to nonunion at 8 weeks post-fracture. Rats received local administration of the following cells or PBS alone(1)cEx-BM, (2)BM, (3)GM-PB CD34+ cells or (4)PBS.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_16 | Pages 24 - 24
1 Apr 2013
Kawakami Y Kuroda T Matsumoto T Kwon S Ii M Kawamoto A Mifune Y Shoji T Kuroda R Kurosaka M Asahara T
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Introduction

CXC chemokine receptor 4 (CXCR4) is a specific receptor for stromal-derived-factor 1 (SDF-1). SDF-1/CXCR4 interaction contributes to the regulation of endotherial progenitor cell (EPC) recruitment in ischemic tissues. The purpose of this study is to investigate the mechanistic function of CXCR4 on EPCs for bone fracture healing.

Materials and methods

We made CXCR4 gene knockout mice using the Cre/loxP system. A reproducible model of femoral fracture was created in both Tie2-Cre CXCR4 knockout mice (CXCR4KO) and wild type mice (control). To evaluate gain function of the SDF-1/CXCR4 pathway, we set three groups of the SDF-1 intraperitoneally injected group, wild type group, and SDF-1 injected CXCR4 KO group.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_16 | Pages 90 - 90
1 Apr 2013
Kawakami Y Matsumoto T Ii M Kawamoto A Kuroda R Mifune Y Shoji T Fukui T Kurosaka M Asahara T
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Introduction

The therapeutic potential of hematopoietic stem cells for fracture healing has been demonstrated with mechanistic insight of vasculogenesis and osteogenesis enhancement. Lnk has recently been proved an essential inhibitory signaling molecule in SCF-c-Kit signaling pathway for stem cell self-renewal demonstrating enhanced hematopoietic and osteogenic reconstitution in Lnk-deficient mice. We investigated the hypothesis that down regulation of Lnk enhances regenerative response via vasculogenesis and osteogenesis in fracture healing.

Methods

A reproducible model of femoral fracture was created in mice. Immediately after fracture creation, mice received local administration of the following materials with AteloGene, 10μM (1)Lnk siRNA, (2)control siRNA.