Decellularized Cortical Bone Scaffold Promotes Organized Neovascularization In Vivo

Abstract Ultrasonic guided waves (UGW), which propagate throughout the whole thickness of cortical bone, are attractive in the early diagnosis of osteoporosis. However, it is challenging due to the impact of soft tissue and the inherent difficulties related to the multiparametric inversion of cortical bone quality factors, such as cortical thickness and bulk wave velocities. Therefore, an UGW based multiple-parameter inversion algorithm is developed to predict strength-related factors in this research. In simulation, a free plate (cortical bone) and a bilayer plate (soft tissue and cortical bone) are used to validate the proposed method. The inverted cortical thickness (CTh), longitudinal velocity (V L ) and transverse velocity (V T ) are in accordance with the true value. Then four bovine cortical bone plates are used in the in vitro experiments. Compared with the reference values, the relative errors for cortical thicknesses are 3.96%, 0.83%, 2.87% and 4.25% respectively. In the in vivo measurements, ultrasonic guided waves are collected from ten volunteers’ tibia. The theoretical dispersion curves depicted by the estimated parameters (V T , V L , CTh) match well with the extracted experimental ones. In comparison to the dual-energy x-ray absorptiometry (DXA), the results show that the estimated transverse velocity and cortical thickness are highly sensitive to the osteoporosis. Therefore, these two parameters (CTh and V T ) of long bones have potential to diagnose bone status in clinical applications.

Download Full-text

In Vivo Assessment of Cortical Bone Fragility

Current Osteoporosis Reports ◽

10.1007/s11914-020-00558-7 ◽

2020 ◽

Vol 18 (1) ◽

pp. 13-22

Author(s):

Lyn Bowman ◽

Anne B. Loucks

Keyword(s):

Cortical Bone ◽

Bone Fragility ◽

In Vivo Assessment

Download Full-text

Cortical bone adaptation to a moderate level of mechanical loading in male Sost deficient mice

Scientific Reports ◽

10.1038/s41598-020-79098-0 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Haisheng Yang ◽

Alexander Büttner ◽

Laia Albiol ◽

Catherine Julien ◽

Tobias Thiele ◽

...

Keyword(s):

Physical Activity ◽

Bone Formation ◽

Bone Mass ◽

Cortical Bone ◽

Bone Adaptation ◽

Moderate Level ◽

Skeletal Maturation ◽

Male Mice ◽

Males And Females

AbstractLoss-of-function mutations in the Sost gene lead to high bone mass phenotypes. Pharmacological inhibition of Sost/sclerostin provides a new drug strategy for treating osteoporosis. Questions remain as to how physical activity may affect bone mass under sclerostin inhibition and if that effect differs between males and females. We previously observed in female Sost knockout (KO) mice an enhanced cortical bone formation response to a moderate level of applied loading (900 με at the tibial midshaft). The purpose of the present study was to examine cortical bone adaptation to the same strain level applied to male Sost KO mice. Strain-matched in vivo compressive loading was applied to the tibiae of 10-, 26- and 52-week-old male Sost KO and littermate control (LC) mice. The effect of tibial loading on bone (re)modeling was measured by microCT, 3D time-lapse in vivo morphometry, 2D histomorphometry and gene expression analyses. As expected, Sost deficiency led to high cortical bone mass in 10- and 26-week-old male mice as a result of increased bone formation. However, the enhanced bone formation associated with Sost deficiency did not appear to diminish with skeletal maturation. An increase in bone resorption was observed with skeletal maturation in male LC and Sost KO mice. Two weeks of in vivo loading (900 με at the tibial midshaft) induced only a mild anabolic response in 10- and 26-week-old male mice, independent of Sost deficiency. A decrease in the Wnt inhibitor Dkk1 expression was observed 3 h after loading in 52-week-old Sost KO and LC mice, and an increase in Lef1 expression was observed 8 h after loading in 10-week-old Sost KO mice. The current results suggest that long-term inhibition of sclerostin in male mice does not influence the adaptive response of cortical bone to moderate levels of loading. In contrast with our previous strain-matched study in females showing enhanced bone responses with Sost ablation, these results in males indicate that the influence of Sost deficiency on the cortical bone formation response to a moderate level of loading differs between males and females. Clinical studies examining antibodies to inhibit sclerostin may need to consider that the efficacy of additional physical activity regimens may be sex dependent.

Download Full-text

Development of a wave front removal algorithm for an ultrasonic axial transmission device used for the in vivo mechanical characterization of cortical bone

Journal of Biomechanics ◽

10.1016/s0021-9290(06)84890-6 ◽

2006 ◽

Vol 39 ◽

pp. S464

Author(s):

M. Sasso ◽

M. Talmant ◽

G. Haïat ◽

P. Laugier ◽

S. Naïli

Keyword(s):

Cortical Bone ◽

Wave Front ◽

Mechanical Characterization ◽

Axial Transmission

Download Full-text

A Review on Recent Advances in the Constitutive Modeling of Bone Tissue

Current Osteoporosis Reports ◽

10.1007/s11914-020-00631-1 ◽

2020 ◽

Vol 18 (6) ◽

pp. 696-704

Author(s):

Dieter H. Pahr ◽

Andreas G. Reisinger

Keyword(s):

Cortical Bone ◽

Constitutive Models ◽

Simulation Models ◽

Material Model ◽

Element Analysis ◽

Physical Mechanisms ◽

Constitutive Material Model ◽

Recent Advances ◽

Osteoporosis Research

Abstract Purpose of Review Image-based finite element analysis (FEA) to predict and understand the biomechanical response has become an essential methodology in musculoskeletal research. An important part of such simulation models is the constitutive material model of which recent advances are summarized in this review. Recent Findings The review shows that existing models from other fields were introduced, such as cohesion zone (cortical bone) or phase-field models (trabecular bone). Some progress has been made in describing cortical bone involving physical mechanisms such as microcracks. Problems with validations at different length scales remain a problem. Summary The improvement of recent constitutive models is partially obscured by uncertainties that affect overall predictions, such as image quality and calibration or boundary conditions. Nevertheless, in vivo CT-based FEA simulations based on a sophisticated constitutive behavior are a very valuable tool for clinical-related osteoporosis research.

Download Full-text