The impact of microgravity on bone in humans

Grimm, Daniela; Grosse, Jirka; Wehland, Markus; Mann, Vivek; Reseland, Janne Elin; Sundaresan, Alamelu; Corydon, Thomas J.

doi:10.1016/j.bone.2015.12.057

Cited by 201 publications

(149 citation statements)

References 158 publications

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“…The higher resorption activity leads to a dramatic reduction of bone volume (mainly in cortical bones) allowing osteoclasts to resorb greater amounts of high mineralized bone material and therefore substantially decreasing ρ mat , which is in agreement with the experimental observations from [41]. Hence, all the points on the densities curve trajectory move to the left of the equilibrium case towards zones of less dense tissue (Fig 7B).…”

Section: Resultssupporting

confidence: 89%

Localized tissue mineralization regulated by bone remodelling: A computational approach

et al. 2017

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Bone is a living tissue whose main mechanical function is to provide stiffness, strength and protection to the body. Both stiffness and strength depend on the mineralization of the organic matrix, which is constantly being remodelled by the coordinated action of the bone multicellular units (BMUs). Due to the dynamics of both remodelling and mineralization, each sample of bone is composed of structural units (osteons in cortical and packets in cancellous bone) created at different times, therefore presenting different levels of mineral content. In this work, a computational model is used to understand the feedback between the remodelling and the mineralization processes under different load conditions and bone porosities. This model considers that osteoclasts primarily resorb those parts of bone closer to the surface, which are younger and less mineralized than older inner ones. Under equilibrium loads, results show that bone volumes with both the highest and the lowest levels of porosity (cancellous and cortical respectively) tend to develop higher levels of mineral content compared to volumes with intermediate porosity, thus presenting higher material densities. In good agreement with recent experimental measurements, a boomerang-like pattern emerges when plotting apparent density at the tissue level versus material density at the bone material level. Overload and disuse states are studied too, resulting in a translation of the apparent–material density curve. Numerical results are discussed pointing to potential clinical applications.

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Section: Resultssupporting

confidence: 89%

Localized tissue mineralization regulated by bone remodelling: A computational approach

et al. 2017

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“…Bone loss and cartilage breakdown in microgravity occurs after a long-term spaceflight [7]. Due to the poor regenerative capacity of cartilage tissue, this degradation may disturb the flight crews' mobility and may negatively influence mission activities [8].…”

Section: Introductionmentioning

confidence: 99%

Pathway Analysis Hints Towards Beneficial Effects of Long-Term Vibration on Human Chondrocytes

Lützenberg

Solano

Buken

et al. 2018

Cell Physiol Biochem

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Background/Aims: Spaceflight negatively influences the function of cartilage tissue in vivo. In vitro human chondrocytes exhibit an altered gene expression of inflammation markers after a two-hour exposure to vibration. Little is known about the impact of long-term vibration on chondrocytes. Methods: Human cartilage cells were exposed for up to 24 h (VIB) on a specialised vibration platform (Vibraplex) simulating the vibration profile which occurs during parabolic flights and compared to static control conditions (CON). Afterwards, they were investigated by phase-contrast microscopy, rhodamine phalloidin staining, microarray analysis, qPCR and western blot analysis. Results: Morphological investigations revealed no changes between CON and VIB chondrocytes. F-Actin staining showed no alterations of the cytoskeleton in VIB compared with CON cells. DAPI and TUNEL staining did not identify apoptotic cells. ICAM-1 was elevated and vimentin, beta-tubulin and osteopontin proteins were significantly reduced in VIB compared to CON cells. qPCR of cytoskeletal genes, ITGB1, SOX3, SOX5, SOX9 did not reveal differential regulations. Microarray analysis detected 13 differentially expressed genes, mostly indicating unspecific stimulations. Pathway analyses demonstrated interactions of PSMD4 and CNOT7 with ICAM. Conclusions: Long-term vibration did not damage human chondrocytes in vitro. The reduction of osteopontin protein and the down-regulation of PSMD4 and TBX15 gene expression suggest that in vitro long-term vibration might even positively influence cultured chondrocytes.

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“…In situations of disuse, bone loss will occur quickly because the body no longer needs to metabolically support such a large structure for load bearing ability [22]. A common example is astronauts, who often experience bone loss due to microgravity while in space [23][24][25][26]. In a study of long-duration flights (average duration approximately 6 months), almost all long-duration astronauts experienced at least a 3% bone loss in at least one skeletal site, while 43% showed at least a 10% bone loss in at least one skeletal site [27].…”

Section: Figmentioning

confidence: 99%

Bone Quality and Quantity are Mediated by Mechanical Stimuli

Berman

Wallace

2016

Clinic Rev Bone Miner Metab

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Prevention of fracture through improved bone mechanical strength is of great importance given the large number of bone disease-related fractures each year, the decreased quality of life associated with fractures, and the large anticipated increase in fracture incidence over the upcoming years due to the aging population. Exercise and other forms of mechanical stimulation have been shown to increase bone mass, suggesting improved strength. However, while bone mass is a good indicator of strength, other components (such as bone quality) also contribute to bone mechanical integrity. While increased bone mass has been explored considerably using both exercise and targeted loading models, the role of mechanical stimulation in altering bone quality has been explored to a lesser degree. Understanding how to improve both the quantity and quality of bone is critical to increasing fracture resistance. Herein, we discuss quantity and quality-based improvements that have been observed using both exercise and targeted loading models of bone adaptation.

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The impact of microgravity on bone in humans

Cited by 201 publications

References 158 publications

Localized tissue mineralization regulated by bone remodelling: A computational approach

Localized tissue mineralization regulated by bone remodelling: A computational approach

Pathway Analysis Hints Towards Beneficial Effects of Long-Term Vibration on Human Chondrocytes

Bone Quality and Quantity are Mediated by Mechanical Stimuli

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