Hyperlipidemia affects multiscale structure and strength of murine femur |
| |
Authors: | Maria-Grazia Ascenzi Andre Lutz Xia Du Laureen Klimecky Neal Kawas Talia Hourany Joelle Jahng Jesse Chin Yin Tintut Udo Nackenhors Joyce Keyak |
| |
Institution: | 1. Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA;2. Continental Tire Company, Hannover, Germany;3. Ostesys, 115 rue Claude Chappe, 29280 Plouzané, France;4. Department of Molecular Oncology, John Wayne Cancer Institute, Santa Monica, CA 90404, USA;5. Department of Medicine, University of California, Los Angeles, CA 90095, USA;6. Institute of Mechanics and Computational Mechanics, Leibniz University Hannover, 30167 Hannover, Germany;g Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697, USA |
| |
Abstract: | To improve bone strength prediction beyond limitations of assessment founded solely on the bone mineral component, we investigated the effect of hyperlipidemia, present in more than 40% of osteoporotic patients, on multiscale structure of murine bone. Our overarching purpose is to estimate bone strength accurately, to facilitate mitigating fracture morbidity and mortality in patients. Because (i) orientation of collagen type I affects, independently of degree of mineralization, cortical bone?s micro-structural strength; and, (ii) hyperlipidemia affects collagen orientation and μCT volumetric tissue mineral density (vTMD) in murine cortical bone, we have constructed the first multiscale finite element (mFE), mouse-specific femoral model to study the effect of collagen orientation and vTMD on strength in Ldlr−/−, a mouse model of hyperlipidemia, and its control wild type, on either high fat diet or normal diet. Each µCT scan-based mFE model included either element-specific elastic orthotropic properties calculated from collagen orientation and vTMD (collagen-density model) by experimentally validated formulation, or usual element-specific elastic isotropic material properties dependent on vTMD-only (density-only model). We found that collagen orientation, assessed by circularly polarized light and confocal microscopies, and vTMD, differed among groups and that microindentation results strongly correlate with elastic modulus of collagen-density models (r2=0.85, p=10−5). Collagen-density models yielded (1) larger strains, and therefore lower strength, in simulations of 3-point bending and physiological loading; and (2) higher correlation between mFE-predicted strength and 3-point bending experimental strength, than density-only models. This novel method supports ongoing translational research to achieve the as yet elusive goal of accurate bone strength prediction. |
| |
Keywords: | Collagen type I Mouse bone High fat diet Hyperlipidemia Multiscale finite element |
本文献已被 ScienceDirect 等数据库收录! |
|