Vitamin D enhanced the osteogenic response of Adolescent Idiopathic Scoliosis primary osteoblasts to vibration
Refereed conference paper presented and published in conference proceedings

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AbstractIntroduction: Adolescent idiopathic scoliosis (AIS) is a complex rotational spinal deformity affecting children during their pubertal growth spurt. Unclear etiopathogenesis restricts current treatment regimes which are targeting the complication of spinal deformity. AIS is associated with systemic low bone mineral density (BMD). In 2005, we reported that low BMD was a significant prognostic factor for curve progression (OR = 2.3). These observations led us to investigate if bone mineralization is a novel therapeutic target for the clinical management of AIS. Our randomized controlled trial (RCT) showed anabolic bone effects of whole body vibration (WBV) in AIS girls which was more effective at sufficient serum Vit-D level. With the well-established primary osteoblasts culture, we aimed to investigate the role of Vit-D in modulating the effect of WBV on osteoblasts activity.

Subjects and method: In this in vitro case-control study, primary osteoblasts were isolated from iliac crest bone biopsies harvested from AIS patients (n = 10) and non-AIS control (n = 5) subjects intra-operatively. Osteoblasts were treated with 0, 10 nM and 100nM of 1, 25(OH)2Vit-D3 (Vit-D3) with or without concurrent vibration treatment (0.3g, 35 Hz for 20 minutes daily). Cell metabolic activity was determined by Alamar blue. Gene expression of representative osteogenic markers was detected by qPCR. Mineralization ability was determined by alkaline phosphatase (ALP) staining and Alizarin red staining. Semi-quantitation was done for independent t test analysis.

Results: Despite similar metabolic activity, AIS osteoblasts exhibited lower intrinsic ALP activity and calcium nodules formation. Vit-D treatment did not render additive effect on calcium nodules formation in control group under vibration. On the contrary, 100nM Vit-D positively enhanced the osteogenic effect of vibration in AIS osteoblasts. At transcription level, Vit-D promoted the vibration-induced upregulation of Spp1, Bglap and ALP, but not Col1, in AIS osteoblasts in a concentration-dependent manner. Vit-D co-treatment also promoted the mRNA level of VDR and LRP5 which might partly underlie the positive effect of Vit-D on the anabolic effect of vibration.
Discussion and conclusion: The more sensitive osteogenic response of AIS osteoblasts to concurrent treatment of Vit-D and vibration might be part of the underlying mechanisms of the modulating effect of Vit-D level on anabolic effect of vibration therapy in previous clinical trial. The present study was limited by osteoblasts model which cannot represent the entire mechanosensation system in bone. With a newly established 3D osteocytes model, we are looking at the effects of Vit-D on vibration in AIS primary osteocytes culture.

Funding/support: This study was supported by CUHK Direct Grant (2012.1.034).
All Author(s) ListJ. Zhang, W. Y. W. Lee, H. X. Chen, L. W. H. Cheung, B. K. W. Ng, J. C. Y. Cheng, T. P. Lam
Name of Conference2016 International Combined Meeting of Orthopaedics Research Societies
Start Date of Conference21/09/2016
End Date of Conference25/09/2016
Place of ConferenceXi'an, China
Country/Region of ConferenceChina
Proceedings TitleProceedings of the 2016 International Combined Meeting of Orthopaedic Research Societies
Series TitleProceedings of the 2016 International Combined Meeting of Orthopaedic Research Societies
Year2016
Month10
Volume Number7
PublisherElsevier (Singapore) Pte Ltd.
Place of PublicationInternational
Pages113 - 113
LanguagesEnglish-United Kingdom

Last updated on 2021-27-02 at 23:55