The Effects of Loading Rate and Duration on Mitigation of Osteopenia by Dynamic Muscle Stimulation

Author(s):  
Yi-Xian Qin ◽  
Hoyan Lam ◽  
Murtaza Malbari

Musculoskeletal adaptations to aging and disuse environment have significant physiological effects on skeletal health, i.e., osteopenia and bone loss. Osteoporosis often occurs together with muscle loss. Such musculoskeletal complications cause severe physiologic changes and have been proposed the synergistic effects of muscle function and bone adaptation. The role of mechanobiology in the skeletal tissue may be closely related to load-induced transductive signals, e.g., bone fluid flow, which is proposed to be a critical mediator of bone and muscle adaptation. The skeletal muscle may serve as a muscle pump that may mediate bone mechanotransduction via modulation of intramedullary pressure. Muscular stimulation (MS) is proposed to be used to simultaneously treat both muscle and bone loss. Indeed, our recent data have demonstrated that high frequency, short duration stimulation can inhibit bone loss and muscle atrophy. Although 10 min dynamic loading can effectively attenuate bone loss, it cannot totally recover disuse osteopenia. The optimal parameters required for such treatment are unclear. Studies have separately investigated the optimal signal parameters for bone or muscle. Insertion of recovery periods during high frequency stimulations to extend the loading cycles have shown potential to reduce muscle atrophy by minimizing fatigue and mimicking physiologic contractions, and demonstrated enhancement of bone remodeling. The overall hypothesis for this study is that dynamic MS can enhance anabolic activity in bone, and inhibit bone loss in a functional disuse condition. Combined high frequency and sufficient loading cycle may be able to completely mitigate bone loss induced by disuse osteopenia.

Author(s):  
Adiba Ali ◽  
Yi-Xian Qin

Osteoporosis, induced by aging and long-term disuse, often occurs together with muscle loss. Musculoskeletal disuse causes severe physiologic changes and it has been proposed the synergistic effects of muscle function and bone adaptation. Bone fluid flow has been shown to be induced during mechanical loading, and is proposed to be a critical mediator of bone adaptation. The skeletal muscle may serve as a muscle pump that may mediate bone mechanotransduction via modulation of intramedullary pressure. Thus, muscular stimulation is proposed to be used to simultaneously treat both muscle and bone loss, but the optimal parameters required for such treatment is unclear. Studies have separately investigated the optimal signal parameters for bone or muscle. Insertion of recovery periods during high frequency stimulations have shown potential to reduce muscle atrophy by minimizing fatigue and mimicking physiologic contractions, and demonstrated enhancement of bone remodeling. Our preliminary research has indicated that dynamic muscle contractions within an optimal frequency range can significantly recover disuse induced bone loss. However, the optimal rest periods required to prevent muscle fatigue during stimulations are not clear. The overall objective of this study was to evaluate optimized dynamic muscle stimulations at relatively high frequency, e.g., 20 Hz, and to test the role of varying the rest duration on muscle mass and bone morphology in a functional hind limb disuse mouse model.


Author(s):  
M. Hu ◽  
J. Cheng ◽  
S. Ferreri ◽  
F. Serra-Hsu ◽  
W. Lin ◽  
...  

Bone loss is a critical health problem of astronauts in long-term space missions. A growing number of evidence has pointed out bone fluid flow as a critical regulator in mechanotransductive signaling and bone adaptation. Intramedullary pressure (ImP) is a key mediator for bone fluid flow initiation and it influences the osteogenic signals within the skeleton. The potential ImP-induced bone fluid flow then triggers bone adaptation [1]. Previous in vivo study has demonstrated that ImP induced by oscillatory electrical stimulations can effectively mitigate disuse osteopenia in a frequency-dependent manner in a disuse rat model [2, 3]. In order to develop the translational potentials of ImP, a non-invasive intervention with direct fluid flow coupling is necessary to develop new treatments for microgravity-induced osteopenia/osteoporosis.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Catherine D. Johnson ◽  
Edralin A. Lucas ◽  
Shirin Hooshmand ◽  
Sara Campbell ◽  
Mohammed P. Akhter ◽  
...  

Dietary bioactive components that play a role in improving skeletal health have received considerable attention in complementary and alternative medicine practices as a result of their increased efficacy to combat chronic diseases. The objectives of this study were to evaluate the additive or synergistic effects of dried plum and fructooligosaccharides (FOS) and to determine whether dried plum and FOS or their combination in a soy protein-based diet can restore bone mass in ovarian hormone deficient rats. For this purpose, 72 3-month-old female Sprague-Dawley rats were divided into six groups (n= 12) and either ovariectomized (Ovx, five groups) or sham-operated (sham, one group). The rats were maintained on a semipurified standard diet for 45 days after surgery to establish bone loss. Thereafter, the rats were placed on one of the following dietary treatments for 60 days: casein-based diet (Sham and Ovx), soy-based diet (Ovx + soy) or soy-based diet with dried plum (Ovx + soy + plum), FOS (Ovx + soy + FOS) and combination of dried plum and FOS (Ovx + soy + plum + FOS). Soy protein in combination with the test compounds significantly improved whole-body bone mineral density (BMD). All test compounds in combination with soy protein significantly increased femoral BMD but the combination of soy protein, dried plum and FOS had the most pronounced effect in increasing lumbar BMD. Similarly, all of the test compounds increased ultimate load, indicating improved biomechanical properties. The positive effects of these test compounds on bone may be due to their ability to modulate bone resorption and formation, as shown by suppressed urinary deoxypyridinoline excretion and enhanced alkaline phosphatase activity.


Author(s):  
Y. X. Qin ◽  
M. Hu ◽  
F. Serra-Hsu ◽  
J. Cheng ◽  
S. Ferreri ◽  
...  

Osteoporosis gives rise to fragile bones that have higher fracture risks due to diminished bone mass and altered bone microarchitecture [1]. Mechanical loading mediated bone adaptation has demonstrated promising potentials as a non-pharmacological alteration for both osteogenic response and attenuation of osteopenia [2]. Intramedullary pressure (ImP) has been proposed as a key factor for fluid flow initiation and mechanotransductive signal inductions in bone. It is also suggested that integration of strain signals over time allows low-level mechanical strain in the skeleton to trigger osteogenic activities. The potential bone fluid flow induced by strain and ImP mediates adaptive responses in the skeleton [3]. Previous in vivo studies using oscillatory electrical stimulations showed that dynamic muscle contractions can generate ImP and bone strain to mitigate disuse osteopenia in a frequency-dependent manner. To apply ImP alteration as a means for bone fluid flow regulation, it may be necessary to develop a new method that could couple external loading with internal bone fluid flow. In order to further study the direct effect of ImP on bone adaptation, it was hypothesized that external dynamic hydraulic stimulation (DHS) can generate ImP with minimal strain in a frequency-dependent manner. The aim of this study was to evaluate the immediate effects on local and distant ImP and bone strain induced by a novel, non-invasive dynamic external pressure stimulus in response to a range of loading frequencies.


Thrita ◽  
2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Atefeh Rauofi ◽  
Sirous Farsi ◽  
Seyed Ali Hosseini

Background: Reduced physical activity can cause obesity and metabolic syndrome, leading to fibrosis in cardiac muscles and premature cardiac aging. Physical activity, along with herbal supplements, can have a synergistic effect on preventing cardiac muscle proteolysis. Objectives: In this study, the effects of curcumin and resistance training were assessed on cardiac muscle atrophy in obese rats. Methods: Twenty-four male Sprague rats were categorized into four groups, including the placebo, resistance training, curcumin, and resistance training + curcumin. Resistance training was performed three times a week with three sets in each session, repeated five times for eight weeks. During this time, 150 mg/kg curcumin was administered through gavage. Twenty-four hours after finishing resistance training, surgery was performed on the cardiac muscle, and gene expressions of PGC1-α, FOXO1, Murf-1, Atrogin, Collagen1, and Collagen 3 were assessed with real-time PCR. Results: The expression of PGC1-α and FOXO1 genes in both resistance training and resistance training+curcumin groups significantly increased and decreased, respectively, compared to the control group (P = 0.001). The MuRF1 expression in the curcumin+resistance training group decreased significantly (P = 0.013) compared to the placebo and curcumin groups. The expression of collagen type 1 and type 2 in all the three treatment groups had significant decreases compared to the placebo group (P < 0.05). Conclusions: Considering the results of this study, resistance training and curcumin supplement each alone can prevent cardiac muscle atrophy. However, the simultaneous use of curcumin supplement and resistance training can lead to synergistic effects.


2008 ◽  
Vol 26 (27) ◽  
pp. 4426-4434 ◽  
Author(s):  
Susan L. Greenspan ◽  
Joel B. Nelson ◽  
Donald L. Trump ◽  
Julie M. Wagner ◽  
Megan E. Miller ◽  
...  

Purpose Androgen-deprivation therapy (ADT) for prostate cancer is associated with bone loss and osteoporotic fractures. Our objective was to examine changes in bone density and turnover with sustained, discontinued, or delayed oral bisphosphonate therapy in men receiving ADT. Patients and Methods A total of 112 men with nonmetastatic prostate cancer receiving ADT were randomly assigned to alendronate 70 mg once weekly or placebo in a double-blind, partial-crossover trial with a second random assignment at year 2 for those who initially received active therapy. Outcomes included bone mineral density and bone turnover markers. Results Men initially randomly assigned to alendronate and randomly reassigned at year 2 to continue had additional bone density gains at the spine (mean, 2.3% ± 0.7) and hip (mean, 1.3% ± 0.5%; both P < .01); those randomly assigned to placebo in year 2 maintained density at the spine and hip but lost (mean, −1.9% ± 0.6%; P < .01) at the forearm. Patients randomly assigned to begin alendronate in year 2 experienced improvements in bone mass at the spine and hip, but experienced less of an increase compared with those who initiated alendronate at baseline. Men receiving alendronate for 2 years experienced a mean 6.7% (± 1.2%) increase at the spine and a 3.2% (± 1.5%) at the hip (both P < .05). Bone turnover remained suppressed. Conclusion Among men with nonmetastatic prostate cancer receiving ADT, once-weekly alendronate improves bone density and decreases turnover. A second year of alendronate provides additional skeletal benefit, whereas discontinuation results in bone loss and increased bone turnover. Delay in bisphosphonate therapy appears detrimental to bone health.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Yi-Xian Qin ◽  
Minyi Hu

While mechanotransductive signal is proven essential for tissue regeneration, it is critical to determine specific cellular responses to such mechanical signals and the underlying mechanism. Dynamic fluid flow induced by mechanical loading has been shown to have the potential to regulate bone adaptation and mitigate bone loss. Mechanotransduction pathways are of great interests in elucidating how mechanical signals produce such observed effects, including reduced bone loss, increased bone formation, and osteogenic cell differentiation. The objective of this review is to develop a molecular understanding of the mechanotransduction processes in tissue regeneration, which may provide new insights into bone physiology. We discussed the potential for mechanical loading to induce dynamic bone fluid flow, regulation of bone adaptation, and optimization of stimulation parameters in various loading regimens. The potential for mechanical loading to regulate microcirculation is also discussed. Particularly, attention is allotted to the potential cellular and molecular pathways in response to loading, including osteocytes associated with Wnt signaling, elevation of marrow stem cells, and suppression of adipotic cells, as well as the roles of LRP5 and microRNA. These data and discussions highlight the complex yet highly coordinated process of mechanotransduction in bone tissue regeneration.


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