Regulation of bone mass by mechanical strain magnitude

1985 ◽  
Vol 37 (4) ◽  
pp. 411-417 ◽  
Author(s):  
Clinton T. Rubin ◽  
Lance E. Lanyon
Keyword(s):  
Bone Mass ◽  
Mechanical Strain ◽  
Strain Magnitude

scholarly journals Influence of body weight on bone mass, architecture and turnover

2016 ◽  
Vol 230 (3) ◽  
pp. R115-R130 ◽  
Author(s):  
Urszula T Iwaniec ◽  
Russell T Turner
Keyword(s):  
Body Weight ◽  
Bone Mass ◽  
Adaptive Response ◽  
Regulatory Mechanism ◽  
Mechanical Strain ◽  
Normal Weight ◽  
Adaptive Mechanism ◽  
Mechanical Signaling ◽  
Skeletal Effects ◽  
Surrogate Measures

Weight-dependent loading of the skeleton plays an important role in establishing and maintaining bone mass and strength. This review focuses on mechanical signaling induced by body weight as an essential mechanism for maintaining bone health. In addition, the skeletal effects of deviation from normal weight are discussed. The magnitude of mechanical strain experienced by bone during normal activities is remarkably similar among vertebrates, regardless of size, supporting the existence of a conserved regulatory mechanism, or mechanostat, that senses mechanical strain. The mechanostat functions as an adaptive mechanism to optimize bone mass and architecture based on prevailing mechanical strain. Changes in weight, due to altered mass, weightlessness (spaceflight), and hypergravity (modeled by centrifugation), induce an adaptive skeletal response. However, the precise mechanisms governing the skeletal response are incompletely understood. Furthermore, establishing whether the adaptive response maintains the mechanical competence of the skeleton has proven difficult, necessitating the development of surrogate measures of bone quality. The mechanostat is influenced by regulatory inputs to facilitate non-mechanical functions of the skeleton, such as mineral homeostasis, as well as hormones and energy/nutrient availability that support bone metabolism. Although the skeleton is very capable of adapting to changes in weight, the mechanostat has limits. At the limits, extreme deviations from normal weight and body composition are associated with impaired optimization of bone strength to prevailing body size.

Effects of Mechanical Strain on Osteoblastic Precursor Cells in a Three-Dimensional Scaffold

2007 ◽  
Vol 330-332 ◽  
pp. 1181-1184
Author(s):  
Zhi He Zhao ◽  
Jun Wang ◽  
Yu Bo Fan ◽  
Song Jiao Luo ◽  
Ling Yong Jiang
Keyword(s):  
Collagen Type ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Collagen Type I ◽  
Precursor Cells ◽  
Dynamic Strain ◽  
Type I ◽  
Pcr Assay ◽  
Periodontal Tissues ◽  
Strain Magnitude

It was well recognized that mechanical strain plays a crucial role in periodontal tissues remodeling. The aim of this study was to investigate the effect of mechanical strain on osteoblastic precursor cells in a collagen type I gel scaffold. Rat MSCs were isolated and cultured according to the established method. Cells were induced with osteogenic medium, then seeded in a collagen type I gel and mechanically stretched by application of cyclic biaxial strain 24h later. Strain cycle was set to 1 cycle/min (0.017Hz), and strain magnitude was set to 2%, 5%, 7% elongation. Cells were collected in 0h, 3h, 6h, 9h, 12h, 24h and 48h respectively. ODF and ICAM-1 mRNA were analyzed by RT-PCR assay. The results shown that 2-7% elongation strain, either dynamic or static, inhibited ICAM-1and ODF expression of osteoblastic precursors, and the effects were relative tightly to strain magnitude. The inhibition effects of dynamic strain loading group exceeded the corresponding static strain. This work suggested that appropriate mechanical strech may suppress differentiation of osteoclasts through inhibiting expression of ICAM-1 and ODF. Application of mechanical stress might have a beneficial effect on quantity of generated bone tissue and might be a important factor in tissue engineering of periodontal tissues.

scholarly journals Fibronectin and Cyclic Strain Improve Cardiac Progenitor Cell Regenerative PotentialIn Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Kristin M. French ◽  
Joshua T. Maxwell ◽  
Srishti Bhutani ◽  
Shohini Ghosh-Choudhary ◽  
Marcos J. Fierro ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Mechanical Strain ◽  
Cyclic Strain ◽  
Collagen I ◽  
Vascular Endothelial ◽  
Lower Strain ◽  
Strain Magnitude ◽  
Endothelial Growth Factor

Cardiac progenitor cells (CPCs) have rapidly advanced to clinical trials, yet little is known regarding their interaction with the microenvironment. Signaling cues present in the microenvironment change with development and disease. This work aims to assess the influence of two distinct signaling moieties on CPCs: cyclic biaxial strain and extracellular matrix. We evaluate four endpoints for improving CPC therapy: paracrine signaling, proliferation, connexin43 expression, and alignment. Vascular endothelial growth factor A (about 900 pg/mL) was secreted by CPCs cultured on fibronectin and collagen I. The application of mechanical strain increased vascular endothelial growth factor A secretion 2–4-fold for CPCs cultured on poly-L-lysine, laminin, or a naturally derived cardiac extracellular matrix. CPC proliferation was at least 25% higher on fibronectin than that on other matrices, especially for lower strain magnitudes. At 5% strain, connexin43 expression was highest on fibronectin. With increasing strain magnitude, connexin43 expression decreased by as much as 60% in CPCs cultured on collagen I and a naturally derived cardiac extracellular matrix. Cyclic mechanical strain induced the strongest CPC alignment when cultured on fibronectin or collagen I. This study demonstrates that culturing CPCs on fibronectin with 5% strain magnitude is optimal for their vascular endothelial growth factor A secretion, proliferation, connexin43 expression, and alignment.

scholarly journals Do mechanical strain magnitude and rate drive bone adaptation in adult women? A 12-month prospective randomized trial

2018 ◽  
Author(s):  
Karen L. Troy ◽  
Megan E. Mancuso ◽  
Joshua E. Johnson ◽  
Zheyang Wu ◽  
Thomas J. Schnitzer ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Healthy Adult ◽  
High Strain ◽  
Mechanical Strain ◽  
Bone Adaptation ◽  
Adult Women ◽  
Loading Dose ◽  
Osteoporosis Prevention ◽  
Strain Magnitude

AbstractAlthough there is strong evidence that certain activities can increase bone density and structure in some individuals, it is unclear what specific mechanical factors govern the response. This is important because understanding the effect of mechanical signals on bone could contribute to more effective osteoporosis prevention methods and efficient clinical trial design. The degree to which strain rate and magnitude govern bone adaptation in humans has never been prospectively tested. Here, we studied the effects of a voluntary upper extremity compressive loading task in healthy adult women during a twelve month prospective period. One hundred and two women age 21-40 participated in one of two experiments. (1): low (n=21) and high (n=24) strain magnitude. (2): low (n=21) and high (n=20) strain rate. Control: (n=16): no intervention. Strains were assigned using subject-specific finite element models. Load cycles were recorded digitally. The primary outcome was change in ultradistal integral bone mineral content (iBMC), assessed with QCT. Interim timepoints and secondary outcomes were assessed with high resolution pQCT (HRpQCT). Sixty-six subjects completed the intervention, and interim data were analyzed for 77 subjects. Both the low and high strain rate groups had significant 12-month increases to ultradistal iBMC (change in control: -1.3±2.7%, low strain rate: 2.7±2.1%, high strain rate: 3.4±2.2%), total iBMC, and other measures. “Loading dose” was positively related to 12-month change in ultradistal iBMC, and interim changes to total BMD, cortical thickness and inner trabecular BMD. Subjects who gained the most bone completed, on average, 130 loading bouts of (mean strain) 550 με at 1805 με/s. Those with the greatest gains had the highest loading dose. We conclude that signals related to strain magnitude, rate, and number of loading bouts contribute to bone adaptation in healthy adult women, but only explain a small amount of variance in bone changes.

Mechanotransduction in bone: osteoblasts are more responsive to fluid forces than mechanical strain

1997 ◽  
Vol 273 (3) ◽  
pp. C810-C815 ◽  
Author(s):  
I. Owan ◽  
D. B. Burr ◽  
C. H. Turner ◽  
J. Qiu ◽  
Y. Tu ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Type I Collagen ◽  
Bone Matrix ◽  
Mechanical Strain ◽  
Extracellular Fluid ◽  
Mechanical Stretch ◽  
Type I ◽  
Physiological Strain ◽  
Fluid Forces ◽  
Strain Magnitude

Mechanical force applied to bone produces two localized mechanical signals on the cell: deformation of the extracellular matrix (substrate strain) and extracellular fluid flow. To study the effects of these stimuli on osteoblasts, MC3T3-E1 cells were grown on type I collagen-coated plastic plates and subjected to four-point bending. This technique produces uniform levels of physiological strain and fluid forces on the cells. Each of these parameters can be varied independently. Osteopontin (OPN) mRNA expression was used to assess the anabolic response of MC3T3-E1 cells. When fluid forces were low, neither strain magnitude nor strain rate was correlated with OPN expression. However, higher-magnitude fluid forces significantly increased OPN message levels independently of the strain magnitude or rate. These data indicate that fluid forces, and not mechanical stretch, influence OPN expression in osteoblasts and suggest that fluid forces induced by extracellular fluid flow within the bone matrix may play an important role in bone formation in response to mechanical loading.

Does short-term administration of glucagon-like peptide type 2 affect bone mass and markers of bone remodeling in short bowel patients?

2001 ◽  
Vol 120 (5) ◽  
pp. A314-A314
Author(s):  
K HADERSLEV ◽  
P JEPPESEN ◽  
B HARTMANN ◽  
J THULESEN ◽  
J GRAFF ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Remodeling ◽  
Short Term ◽  
Short Bowel ◽  
Term Administration ◽  
Glucagon Like Peptide
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