Prevention of postmenopausal bone loss by a low-magnitude, high-frequency mechanical stimuli: a clinical trial assessing compliance, efficacy, and safety

Low-intensity vibration restores nuclear YAP levels and acute YAP nuclear shuttling in mesenchymal stem cells subjected to simulated microgravity

Reducing the musculoskeletal deterioration that astronauts experience in microgravity requires countermeasures that can improve the effectiveness of otherwise rigorous and time-expensive exercise regimens in space. The ability of low-intensity vibrations (LIV) to activate force-responsive signaling pathways in cells suggests LIV as a potential countermeasure to improve cell responsiveness to subsequent mechanical challenge. Mechanoresponse of mesenchymal stem cells (MSC), which maintain bone-making osteoblasts, is in part controlled by the "mechanotransducer" protein YAP (Yes-associated protein), which is shuttled into the nucleus in response to cyto-mechanical forces. Here, using YAP nuclear shuttling as a measurement outcome, we tested the effect of 72 h of clinostat-induced simulated microgravity (SMG) and daily LIV application (LIVDT) on the YAP nuclear entry driven by either acute LIV (LIVAT) or Lysophosphohaditic acid (LPA), applied after the 72 h period. We hypothesized that SMG-induced impairment of acute YAP nuclear entry would be alleviated by the daily application of LIVDT. Results showed that while both acute LIVAT and LPA treatments increased nuclear YAP entry by 50 and 87% over the basal levels in SMG-treated MSCs, nuclear YAP levels of all SMG groups were significantly lower than non-SMG controls. LIVDT, applied in parallel to SMG, restored the SMG-driven decrease in basal nuclear YAP to control levels as well as increased the LPA-induced but not LIVAT-induced YAP nuclear entry over SMG only, counterparts. These cell-level observations suggest that daily LIV treatments are a feasible countermeasure for restoring basal nuclear YAP levels and increasing the YAP nuclear shuttling in MSCs under SMG.

Exercise and Diet: Uncovering Prospective Mediators of Skeletal Fragility in Bone and Marrow Adipose Tissue

PURPOSE OF REVIEW

To highlight recent basic, translational, and clinical works demonstrating exercise and diet regulation of marrow adipose tissue (MAT) and bone and how this informs current understanding of the relationship between marrow adiposity and musculoskeletal health.

RECENT FINDINGS

Marrow adipocytes accumulate in the bone in the setting of not only hypercaloric intake (calorie excess; e.g., diet-induced obesity) but also with hypocaloric intake (calorie restriction; e.g., anorexia), despite the fact that these states affect bone differently. With hypercaloric intake, bone quantity is largely unaffected, whereas with hypocaloric intake, bone quantity and quality are greatly diminished. Voluntary running exercise in rodents was found to lower MAT and promote bone in eucaloric and hypercaloric states, while degrading bone in hypocaloric states, suggesting differential modulation of MAT and bone, dependent upon whole-body energy status. Energy status alters bone metabolism and bioenergetics via substrate availability or excess, which plays a key role in the response of bone and MAT to mechanical stimuli. Marrow adipose tissue (MAT) is a fat depot with a potential role in-as well as responsivity to-whole-body energy metabolism. Understanding the localized function of this depot in bone cell bioenergetics and substrate storage, principally in the exercised state, will aid to uncover putative therapeutic targets for skeletal fragility.

Influence of Low-Magnitude High-Frequency Vibration on Bone Cells and Bone Regeneration

Bone is a mechanosensitive tissue for which mechanical stimuli are crucial in maintaining its structure and function. Bone cells react to their biomechanical environment by activating molecular signaling pathways, which regulate their proliferation, differentiation, and matrix production. Bone implants influence the mechanical conditions in the adjacent bone tissue. Optimizing their mechanical properties can support bone regeneration. Furthermore, external biomechanical stimulation can be applied to improve implant osseointegration and accelerate bone regeneration. One promising anabolic therapy is vertical whole-body low-magnitude high-frequency vibration (LMHFV). This form of vibration is currently extensively investigated to serve as an easy-to-apply, cost-effective, and efficient treatment for bone disorders and regeneration. This review aims to provide an overview of LMHFV effects on bone cells in vitro and on implant integration and bone fracture healing in vivo. In particular, we review the current knowledge on cellular signaling pathways which are influenced by LMHFV within bone tissue. Most of the in vitro experiments showed that LMHFV is able to enhance mesenchymal stem cell (MSC) and osteoblast proliferation. Furthermore, osteogenic differentiation of MSCs and osteoblasts was shown to be accelerated by LMHFV, whereas osteoclastogenic differentiation was inhibited. Furthermore, LMHFV increased bone regeneration during osteoporotic fracture healing and osseointegration of orthopedic implants. Important mechanosensitive pathways mediating the effects of LMHFV might be the Wnt/beta-catenin signaling pathway, the estrogen receptor (ER) signaling pathway, and cytoskeletal remodeling.

Sports and Metabolic Bone Disease

Physical activity (PA) increases bone mass and bone strength through different mechanisms and also reduces the risk of falls in the elderly, through proprioception and balance training. The benefits seen in adolescence continue into adulthood. Exercise delays and attenuates the effects of osteoporosis, and particular sports activities may be recommended to improve bone mineral density (BMD) of the spine or regional BMD, improve balance, and prevent falls. Stress injuries related to exercise are more common in osteopenic and osteoporotic individuals.Sports activity may in some cases be detrimental for bone health, with nutrition restriction a frequent cause for negative effects of the practice of PA on bone. The examples are the so-called female athlete triad of menstrual dysfunction resulting in reduced estrogen levels, low energy due to malnutrition, and decreased BMD. A similar triad is described in male athletes. This review analyzes the effects of sport on bone metabolism and in particular its relationship with metabolic bone disease.

[Neuromuscular stimulation in conditions of vibrational physical activity for the prevention of osteoporosis]

The review discusses the modern possibilities of non-drug rehabilitation of patients with osteoporosis. Osteopenia (osteoporosis) and osteoporosis-associated bone fractures are a global public health problem, and an intensive search is undergoing for new methods of treatment, prevention, diagnosis and screening of this disease. Innovative technologies for influencing bone remodeling using vibration training seem to be an effective method that allows you to simultaneously positively affect maintaining bone density, increasing muscle strength and improving coordination, especially in elderly patients. The evolution of study of the effects of intense neuromuscular stimulation under accelerated physical exertion, which began with fundamental work on experimental animals, now includes numerous clinical studies. Vibrational physical activity is one of the methods of biomechanical stimulation, which is considered as an innovative method in the field of rehabilitation and physiotherapy. The physiological basis of this effect is intensive neuromuscular stimulation, which causes a reflex reaction of skeletal muscles. This scientific review describes the results of both monotherapy and combined methods of exposure to vibrational stimulation using modern pharmacotherapy. Attention is focused on the positions of importance in the design of the study and the planning of rehabilitation programs of uniformly accelerated training.

Pain After Whole-Body Vibration Exposure Is Frequency Dependent and Independent of the Resonant Frequency: Lessons From an In Vivo Rat Model

Occupational whole-body vibration (WBV) increases the risk of developing low back and neck pain; yet, there has also been an increased use of therapeutic WBV in recent years. Although the resonant frequency (fr) of the spine decreases as the exposure acceleration increases, effects of varying the vibration profile, including peak-to-peak displacement (sptp), root-mean-squared acceleration (arms), and frequency (f), on pain onset are not known. An established in vivo rat model of WBV was used to characterize the resonance of the spine using sinusoidal sweeps. The relationship between arms and fr was defined and implemented to assess behavioral sensitivity-a proxy for pain. Five groups were subjected to a single 30-min exposure, each with a different vibration profile, and a sham group underwent only anesthesia exposure. The behavioral sensitivity was assessed at baseline and for 7 days following WBV-exposure. Only WBV at 8 Hz induced behavioral sensitivity, and the higher arms exposure at 8 Hz led to a more robust pain response. These results suggest that the development of pain is frequency-dependent, but further research into the mechanisms leading to pain is warranted to fully understand which WBV profiles may be detrimental or beneficial.

The Impact of Different Modes of Exercise Training on Bone Mineral Density in Older Postmenopausal Women: A Systematic Review and Meta-analysis Research

Effectiveness of exercise on bone mass is closely related to the mode of exercise training regimen, as well as the study design. This study aimed to determine the effect of different modes of exercise training on lumbar spine and femoral neck bone mineral density (BMD) in older postmenopausal women (PMW). PubMed, CINAHL, Medline, Google Scholar, and Scopus databases and reference lists of included studies were searched up until March 25, 2019 for randomized controlled trials (RCTs) that evaluated the effectiveness of various modes of exercise training in PMW. Sixteen RCTs with 1624 subjects were included. Our study found no significant change in both lumbar spine and femoral neck BMD following exercise training (MD: 0.01 g/cm2; 95% confidence interval (CI) [- 0.01, 0.02] and MD: 0.00 g/cm2; 95% CI [- 0.01, 0.01], respectively). However, subgroup analysis by type of exercise training revealed that lumbar spine BMD (MD: 0.01; 95% CI [0.00, 0.02]) raised significantly when whole-body vibration (WBV) was employed as intervention compared with RCTs that utilized aerobic (MD: - 0.01; 95% CI [- 0.02, - 0.01]), resistance (MD: 0.01; 95% CI [- 0.04, 0.06]), and combined training (MD: 0.03; 95% CI [- 0.01, 0.08]). On the other hand, lumbar spine BMD (MD: - 0.01; 95% CI [- 0.02, - 0.01]) reduced significantly when aerobic exercise training was used as intervention compared with RCTs that utilized resistance training, combined training, and WBV. By contrast, these analyses did not have significant effect on change in femoral neck BMD. WBV is an effective method to improve lumbar spine BMD in older PMW.

Effects of whole-body vibration and high impact exercises on the bone metabolism and functional mobility in postmenopausal women

INTRODUCTION

This study determined the effects of whole-body vibration (WBV) and high-impact exercises on postmenopausal women.

MATERIALS AND METHODS

In this randomized controlled 6-month interventional trial, 58 eligible postmenopausal women were assigned to WBV training group, high-impact training group, or control group. Bone mineral density (BMD) of the lumbar spine and femur were measured by dual-energy X-ray absorptiometry. Additionally, the serum osteocalcin (OC) and C-terminal telopeptide of type I collagen levels were also measured. The functional mobility was assessed using the Timed Up and Go (TUG) test, and fall index was measured using static posturography. The health-related quality of life (HRQoL) and depressive symptoms were assessed using the Quality of Life Questionnaire of the European Foundation for Osteoporosis and Beck Depression Inventory, respectively.

RESULTS

The BMD at the femoral neck (p = 0.003) and L₂-L₄ (p = 0.005) regions increased significantly in the WBV group compared to the control group. However, in the high-impact exercise group there were no significant effects on the lumbar spine and femoral neck. The serum OC decreased significantly in the WBV group and increased significantly in both the high-impact exercise and control groups (p < 0.001). The TUG scores decreased significantly in both training groups compared to the control group (p < 0.05). Finally, in both exercise groups, HRQoL and depressive symptoms improved (p < 0.001).

CONCLUSIONS

Our data suggest that the WBV can prevent bone loss in postmenopausal women. These findings also indicate that WBV and high-impact training programs improve functional mobility, HRQoL and depressive symptoms in postmenopausal women.

Vibration and β-hydroxy-β-methylbutyrate treatment suppresses intramuscular fat infiltration and adipogenic differentiation in sarcopenic mice

BACKGROUND

Sarcopenia is an aging-induced deterioration of skeletal muscle mass and function. Low-magnitude high-frequency vibration (LMHFV) was shown to improve muscle functions and β-hydroxy-β-methylbutyrate (HMB) to increase muscle mass and strength. Muscle-derived stem cells (MDSCs) are progenitor cells important for muscle regeneration. We hypothesized that LMHFV and HMB could retard sarcopenia by reducing fat infiltration through inhibiting adipogenesis in MDSCs.

METHODS

Senescence-accelerated mouse P8 male mice were randomized into control (CTL), HMB, LMHFV (VIB), and combined (COM) groups. Interventions started at age of month 7 and assessed at 1, 2, and 3 months post-intervention by densitometry, histology, and functional tests. In vitro, MDSCs isolated from gastrocnemius of senescence-accelerated mouse P8 mice were characterized, randomized into CTL, VIB, HMB, and COM groups, and assessed by oil red O staining, mRNA, and protein expression.

RESULTS

At 2 months post-intervention, percentage lean mass of HMB, VIB, and COM groups were significantly higher than CTL group. Twitch, tetanic, and specific tetanic forces of COM group were higher, while specific twitch force of both VIB and COM groups were higher. Grip strength of HMB, VIB, and COM groups were higher. Histologically, both VIB and COM groups presented lower oil red O area than CTL group. Type I muscle fibre in CTL group was higher than HMB, VIB, and COM groups. MDSC were detected in situ by immunofluorescence stain with stem cell antigen-1 signals confirmed with higher β-catenin expression in the COM group. The observations were also confirmed in vitro, MDSCs in the HMB, VIB, and COM groups presented lower adipogenesis vs. the CTL group. β-Catenin mRNA and protein expressions were lower in the CTL group while their relationship was further validated through β-catenin knock-down approach.

CONCLUSIONS

Our results showed that combined LMHFV and HMB interventions enhanced muscle strength and decreased percentage fat mass and intramuscular fat infiltration as compared with either treatment alone. Additive effect of LMHFV and HMB was demonstrated in β-catenin expression than either treatment in MDSCs and altered cell fate from adipogenesis to myogenesis, leading to inhibition of intramuscular lipid accumulation. Wnt/β-catenin signalling pathway was found to be the predominant regulatory mechanism through which LMHFV and HMB combined treatment suppressed MDSCs adipogenesis.

Effects of Whole-Body Vibration Versus Pilates Exercise on Bone Mineral Density in Postmenopausal Women: A Randomized and Controlled Clinical Trial

BACKGROUND AND PURPOSE

Decreased bone mineral density (BMD) is a common condition in postmenopausal women that can be managed with impact activities. Among the activities studied are the whole-body vibration (WBV) and muscle-strengthening exercises. The purpose of this study was to compare the effects of WBV versus Pilates exercise on BMD in postmenopausal women.

METHODS

In this study, 51 postmenopausal women were randomized into 3 groups: vibration (n = 17), Pilates (n = 17), and control (n = 17). Outcomes were the areal bone mineral density (aBMD) (lumbar spine, femoral neck, total hip, trochanter, intertrochanter, and ward's area) assessed by dual-energy x-ray absorptiometry at baseline and follow-up. The interventions were performed 3 times a week for 6 months, totaling 78 sessions. The analysis was performed with intention-to-treat and covariance analyses adjusted for baseline outcomes.

RESULTS

After 6 months, 96.1% of the participants completed the follow-up. The analyses demonstrated significant mean between-group differences in favor of the interventions: vibration versus control, for the aBMD of the lumbar spine (0.014 g/cm; 95% confidence interval [CI], 0.006-0.022; P = .018, d = 1.21) and trochanter (0.018 g/cm; 95% CI, 0.006-0.030; P = .012, d = 1.03); and Pilates versus control, for the aBMD of the lumbar spine (0.016 g/cm; 95% CI, 0.007-0.025; P = .008, d = 1.15) and trochanter (0.020 g/cm; 95% CI, 0.010-0.031; P = .005, d = 1.28).

CONCLUSION

In postmenopausal women, 3 weekly sessions of WBV or Pilates administered for 6 months provided an equal effect on BMD.

The long-term residual effects of low-magnitude mechanical stimulation therapy on skeletal health

Background

Low-magnitude mechanical stimulation (LMMS) may improve skeletal health. The objective of this research was to investigate the long-term residual effects of LMMS on bone health. 10-week old female mice were given LMMS for 8 weeks; SHAM did not receive LMMS. Some groups remained on study for an additional 8 or 16 weeks post treatment (N = 17).

Results

Epiphyseal trabecular mineralizing surface to bone surface ratio (MS/BS) and bone formation rate (BFR/BS) were significantly greater in the LMMS group compared to the SHAM group at 8 weeks by 92 and 128% respectively. Mineral apposition rate (MAR) was significantly greater in the LMMS group 16 weeks post treatment by 14%.

Metaphyseal trabecular bone mineral density (BMD) increased by 18%, bone volume tissue volume ratio (BV/TV) increased by 37%, and trabecular thickness (Tb.Th.) increased by 10% with LMMS at 8 weeks post treatment. Significant effects 16 weeks post treatment were maintained for BV/TV and Tb.Th. The middle-cortical region bone volume (BV) increased by 4% and cortical thickness increased by 3% with 8-week LMMS.

Conclusions

LMMS improves bone morphological parameters immediately after and in some cases long-term post LMMS. Results from this work will be helpful in developing treatment strategies to increase bone health in younger individuals.

Effects of Whole-Body Vibration Training on the Physical Function of the Frail Elderly: An Open, Randomized Controlled Trial

OBJECTIVE

To investigate the feasibility and benefits of whole-body vibration (WBV) exercise as a safe and effective training tool for countering sarcopenia and age-related declines in mobility and function in the frail elderly.

DESIGN

An open, randomized controlled trial.

SETTING

Residential care facilities.

PARTICIPANTS

Male and female volunteers (N=117; 82.5±7.9y).

INTERVENTIONS

After prescreening for contraindications, participants were randomly allocated to a control, simulated WBV (SIM), or WBV exercise group. All participants received regular care, whereas WBV and SIM participants also underwent thrice-weekly exercise sessions for 16 weeks. Delivered by overload principle, WBV training began with 5 × 1-minute bouts at 6 Hz/2 mm (1:1 min exercise:rest), progressing to 10 × 1 minute at up to 26 Hz/4 mm, maintaining knee flexion. Training for SIM participants mimicked WBV exercise stance and duration only.

MAIN OUTCOME MEASURES

The timed Up and Go, Parallel Walk, and 10-m Timed Walk (10mTW) tests performance were assessed, in addition to the Barthel Index Questionnaire, at baseline, 8, and 16 weeks of exercise, and 3, 6, and 12 months postexercise.

RESULTS

High levels of compliance were reported in SIM (89%) and WBV training (93%), with ease of use and no adverse effects. In comparison to baseline levels, WBV training elicited clinically important treatment effects in all parameters compared to SIM and control groups. Treatment effects remained apparent up to 12 months postintervention for Parallel Walk Test and 6 months for 10mTW Test. Functional test performance declined during and postintervention in non-WBV groups.

CONCLUSIONS

Findings indicate that 16 weeks of low-level WBV exercise provides easily accessible, adequate stimulus for the frail elderly to attain improved levels of physical functionality.

A novel device to prevent osteoporosis by promoting bone metabolism using a newly developed double-loading stimulation with vibration and shaking

In Japan, 13 million people have osteoporosis, including approximately 9 hundred thousand people who are bedridden owing to bone fractures from falls. Preventing osteoporosis is considered to be an important and effective way of preventing fall-related fractures. Thus, we developed a novel method of locomotor stimulation and analyzed its effectiveness in mice. Specifically, we created a double-loading device that combines vibration and shaking stimulation. The device was used to continuously stimulate ovariectomy-induced decreased bone density mouse models 30 minutes daily for 10 weeks. We then collected femur samples, created undecalcified tissue slices, calculated parameters using bone histomorphomtry, and conducted comparative testing. BS/TV (bone surface/tissue volume), N.Oc/ES (osteoclast number/eroded surface), Oc.S/ES (osteoclast osteoid surface/eroded surface), Omt (osteoid maturation time), Tb.N (trabecular number), Mlt (mineralization lag time) < (p < 0.01), N.Ob (osteoblast number), N.Ob/TV (osteoblast number/tissue volume), sLS (single labeled suface), N.Mu.Oc/ES (multinucle osteoclast number/eroded surface), and N.Mo.Oc/ES (mononucle osteoclast number/eroded surface) (p < 0.05) were significantly higher in the stimulation group than in the non-stimulation group. In addition, BS/BV (bone surface/bone volume), Tb.Sp (trabecular separation), MAR (mineral apposition rate), Aj.Ar (adjusted apposition rate) (p < 0.01), ES (eroded surface ), ES/BS (eroded surface/bone surface), and BRs.R (bone resorption rate) (p < 0.05) were significantly lower in the stimulation group than in the non-stimulation group. These results suggest that stimulation activated osteoblasts and osteoclasts, thereby leading to highly active bone remodeling. We anticipate that bone mineralization will subsequently occur, suggesting that this stimulation technique is effective in preventing osteoporosis by alleviating sudden bone density loss.

Effects of mechanical vibration on cell morphology, proliferation, apoptosis, and cytokine expression/secretion in osteocyte-like MLO-Y4 cells exposed to high glucose

Diabetic patients exhibit significant bone deterioration. Our recent findings demonstrate that mechanical vibration is capable of resisting diabetic bone loss, whereas the relevant mechanism remains unclear. We herein examined the effects of mechanical vibration on the activities and functions of osteocytes (the most abundant and well-recognized mechanosensitive cells in the bone) exposed to high glucose (HG). The osteocytic MLO-Y4 cells were incubated with 50 mM HG for 24 h, and then stimulated with 1 h/day mechanical vibration (0.5 g, 45 Hz) for 3 days. We found that mechanical vibration significantly increased the proliferation and viability of MLO-Y4 cells under the HG environment via the MTT, BrdU, and Cell Viability Analyzer assays. The apoptosis detection showed that HG-induced apoptosis in MLO-Y4 cells was inhibited by mechanical vibration. Moreover, increased cellular area, microfilament density, and anisotropy in HG-incubated MLO-Y4 cells were observed after mechanical vibration via the F-actin fluorescence staining. The real-time polymerase chain reaction and western blotting results demonstrated that mechanical vibration significantly upregulated the gene and protein expression of Wnt3a, β-catenin, and osteoprotegerin (OPG) and decreased the sclerostin, DKK1, and receptor activator for nuclear factor-κB ligand (RANKL) expression in osteocytes exposed to HG. The enzyme-linked immunosorbent assay assays showed that mechanical vibration promoted the secretion of prostaglandin E₂ and OPG, and inhibited the secretion of tumor necrosis factor-α and RANKL in the supernatant of HG-treated MLO-Y4 cells. Together, this study demonstrates that mechanical vibration improves osteocytic architecture and viability, and regulates cytokine expression and secretion in the HG environment, and implies the potential great contribution of the modulation of osteocytic activities in resisting diabetic osteopenia/osteoporosis by mechanical vibration.

Skeletal response to whole body vibration and dietary calcium and phosphorus in growing pigs

The quality and strength of the skeleton is regulated by mechanical loading and adequate mineral intake of calcium (Ca) and phosphorus (P). Whole body vibration (WBV) has been shown to elicit adaptive responses in the skeleton, such as increased bone mass and strength. This experiment was designed to determine the effects of WBV and dietary Ca and P on bone microarchitecture and turnover. A total of 26 growing pigs were utilized in a 60-d experiment. Pigs were randomly assigned within group to a 2 × 2 factorial design with dietary Ca and P concentration (low and adequate) as well as WBV. The adequate diet was formulated to meet all nutritional needs according to the NRC recommendations for growing pigs. Low Ca, P diets had 0.16% lower Ca and 0.13% lower P than the adequate diet. Pigs receiving WBV were vibrated 30 min/d, 3 d/wk at a magnitude of 1 to 2 mm and a frequency of 50 Hz. On days 0, 30, and 60, digital radiographs were taken to determine bone mineral content by radiographic bone aluminum equivalency (RBAE) and serum was collected to measure biochemical markers of bone formation (osteocalcin, OC) and bone resorption (carboxy-terminal collagen crosslinks, CTX-I). At day 60, pigs were euthanized and the left third metacarpal bone was excised for detailed analysis by microcomputed tomography (microCT) to measure trabecular microarchitecture and cortical bone geometry. Maximum RBAE values for the medial or lateral cortices were not affected (P > 0.05) by WBV. Pigs fed adequate Ca and P tended (P = 0.10) to have increased RBAE max values for the medial and lateral cortices. WBV pigs had significantly decreased serum CTX-1 concentrations (P = 0.044), whereas animals fed a low Ca and P diet had increased (P < 0.05) OC concentrations. In bone, WBV pigs showed a significantly lower trabecular number (P = 0.002) and increased trabecular separation (P = 0.003), whereas cortical bone parameters were not significantly altered by WBV or diet (P > 0.05). In summary, this study confirmed the normal physiological responses of the skeleton to a low Ca, P diet. Interestingly, although the WBV protocol utilized in this study did not elicit any significant osteogenic response, decreases in CTX-1 in response to WBV may have been an early local adaptive bone response. We interpret these data to suggest that the frequency and amplitude of WBV was likely sufficient to elicit a bone remodeling response, but the duration of the study may not have captured the full extent of an entire bone remodeling cycle.

Micro-vibrations at 30 Hz on bone cells cultivated in vitro produce soluble factors for osteoclast inhibition and osteoblast activity

OBJETIVE

It has been claimed that micro-pulse vibration can accelerate the rate of tooth movement during orthodontic treatment; however, the underlying cellular mechanism has yet to be elucidated. The purpose of this study was to understand the mechanisms underlying tooth movement acceleration by measuring alterations in a panel of intercellular signalling molecules and markers of osteoblast/osteoclast function following micro-pulse vibration for 20 min at 30 Hz.

DESIGN

Primary BALB/c mouse calvarial osteoblasts were cultivatedin vitro and subjected to micro-pulse vibration (0.25 N; 30 Hz) with the AcceleDent® Aura appliance for 20 min and assayed for IL-4, IL-13, IL-17, OPG, soluble RANKL and TGF-β protein by ELISA; for PCNA in osteoblasts and caspase 3/7 in osteoclasts by immunohistochemistry; for IL-4, IL-13, and Il-17 in osteoclasts by ELISA; and for cathepsin K by flow cytometry.

RESULTS

After micro-pulse vibration, the murine osteoblast culture supernatant showed increased IL-4, IL-13, IL-17, OPG and TGF-β levels and decreased RANKL levels; PCNA in osteoblasts and caspase 3/7 in osteoclasts were also upregulated. The osteoclast culture supernatant had increased levels of IL-4, IL-13 and IL-17, and cathepsin K was upregulated in the treatment group compared with the control group.

CONCLUSIONS

Micro-pulse vibration promotes the production of soluble factors that inhibit osteoclasts, promote apoptosis and activate osteoblasts in vitro, which could increase bone mineral density. Further studies should be conducted in order to understand the biological mechanism of how micro-vibration might influence tooth movement during orthodontic treatment.

Novel insights into the complex architecture of osteoporosis molecular genetics

Osteoporosis is a prevalent osteodegenerative disease and silent killer linked to a decrease in bone mass and decline of bone microarchitecture, due to impaired bone matrix mineralization, raising the risk of fracture. Nevertheless, the process of bone matrix mineralization is still an unsolved mystery. Osteoporosis is a polygenic disorder associated with genetic and environmental risk factors; however, the majority of genes associated with osteoporosis remain largely unknown. Several signaling pathways regulate bone mass; therefore, dysregulation of a single signaling pathway leads to metabolic bone disease owing to high or low bone mass. Parathyroid hormone, core-binding factor α-1 (Cbfa1), Wnt/β-catenin, the receptor activator of the nuclear factor kappa-B (NF-κB) ligand (RANKL), myostatin, and osteogenic exercise signaling pathways play pivotal roles in the regulation of bone mass. The myostatin signaling pathway increases bone resorption by activating the RANKL signaling pathway, whereas osteogenic exercise inhibits myostatin and sclerostin while inducing irisin that consequentially activates the Cbfa1 and Wnt/β-catenin bone formation pathways. The aims of this review are to summarize what is known about osteoporosis-related signaling pathways; define the role of these pathways in osteoporosis drug discovery; focus light on the link between bone, muscle, pancreas, and adipose integrative physiology and osteoporosis; and underline the emerging role of osteogenic exercise in the prevention of, and care for, osteoporosis, obesity, and diabetes.

Quantitative ultrasound imaging monitoring progressive disuse osteopenia and mechanical stimulation mitigation in calcaneus region through a 90-day bed rest human study

Background

Osteoporosis parallels aging and functional mechanical unloading (e.g., space flight and bed rest), jeopardizing mineral density, microstructure, and integrity of bone and leading to an increased risk of fracture. A way to combat this deterioration is to harness the sensitivity of bone to mechanical signals.

Objective

This study evaluates the longitudinal effect of a dynamic mechanical loading through the heel on human bone in vivo during 90-day bed rest, monitored by quantitative ultrasound (QUS) imaging and dual-energy X-ray absorptiometry (DXA) in localized regions of interests, i.e., calcaneus.

Methods

A total of 29 bed rest individuals were evaluated (11 control and 18 treatment) with a brief (10-minute) daily low-intensity (0.3g), high-frequency (30Hz) dynamic mechanical stimulation countermeasure through vibrational inhibition bone erosion (VIBE). Both QUS and DXA detected longitudinal bone density and quality changes.

Results

Ultrasound velocity (UV) decreased in the control group and increased in the group treated with low-intensity loading. The UV increased by 1.9% and 1.6% at 60- and 90-day bed rest (p=0.01) in VIBE over control groups. A trend was found in broadband ultrasound attenuation (BUA), with a VIBE benefit of 1.8% at day 60 and 0.5% at day 90 in comparison with control (p=0.5). Bone mineral density (BMD) assessed by DXA decreased -4.50% for control individuals and -2.18% for VIBE individuals, showing a moderate effect of the mechanical intervention (p=0.19). Significant correlations between QUS and DXA were observed, with a combined BUA and UV vs. BMD: r²=0.70.

Conclusion

These results indicated that low-intensity, high-frequency loading has the potential to mitigate regional bone loss induced by long-term bed rest and that QUS imaging may be able to assess the subtle changes in bone alteration.

Translational potential of this article

Quantitative ultrasound has shown the efficacy of noninvasively assessing bone mass and structural properties in cadaver and isolated trabecular bone samples. While its ability in measuring in vivo bone quality and density is still unclear, a scanning confocal ultrasound imaging is developed and can perform an instant assessment for the subtle changes of such bone loss. This ultrasound imaging modality can potentially be used in the clinical assessment of bone mass. Moreover, physical stimulation has shown the ability to prevent bone loss induced by functional disuse and estrogen deficiency in animal models. However, its treatment capability is unclear. This study has shown that low-magnitude mechanical signals, introduced using low-intensity vibration (LIV), can mitigate regional bone loss caused by functional disuse. Thus localized mechanical treatment, and the quantitative ultrasound imaging have shown translational potential to noninvasively attenuate bone loss, and assess bone mass in the clinic, e.g., in an extreme condition such as long-term space mission, and long-term bedrest such as in case of spinal cord injury.

Effect of high-frequency vibration on orthodontic tooth movement and bone density

OBJECTIVES:

Previous reports have shown that high-frequency vibration can increase bone remodeling and accelerate tooth movement. The aim of this study was to evaluate the effects of high-frequency vibration on treatment phase tooth movement, and post-treatment bone density at initiation of retention, with cone-beam computed tomography (CBCT).

MATERIALS AND METHODS:

Thirty patients with initial Class I skeletal relationships, initial minimum-moderate crowding (3–5 mm), treated to completion with clear aligners and adjunctive high-frequency vibration, (HFV group) or no vibration, (Control group) were evaluated. The patients were instructed to change aligners as soon as they become loose. Changes in bone density associated with orthodontic treatment were evaluated using i-CAT cone-beam computed tomography (CBCT) and InVivo Anatomage^® software to quantify density using Hounsfield units (HU) between treated teeth in 10 different regions. HU values were averaged and compared against baseline (T1) and between the groups at initiation of retention (T2).

RESULTS:

The average time for aligner change was 5.2 days in the HFV group, and 8.7 days in the control group (P = 0.0001). There was significant T1 to T2 increase of HU values in the upper arch (P = 0.0001) and the lower arch (P = 0.008) in the HFV group. There was no significant change in average HU values in the upper (P = 0.83) or lower arches (P = 0.33) in the control group. The intergroup comparison revealed a significant difference in the upper, (P = 0.0001) and lower arches (P = 0.007).

CONCLUSION:

High-frequency vibration adjunctive to clear aligners, allowed early aligner changes that led to shorter treatment time in minimum-moderate crowded cases. At initiation of retention, the HFV group demonstrated statistically significant increase as compared with pre-treatment bone density, whereas control subjects showed no significant change from pre-treatment bone density.

Effects of Two Different Neuromuscular Training Protocols on Regional Bone Mass in Postmenopausal Women: A Randomized Controlled Trial

Background: Osteoporosis is a condition associated with a greater incidence of fractures, and one of the main health-related concerns in postmenopausal women. To counteract possible reductions in bone properties, physical exercise has been proposed as an effective strategy. Particularly, training interventions with a high osteogenic potential are recommended. Purpose: To analyze the effect of 24 weeks of whole-body vibration and multi-component training on lumbar spine and femoral neck bone mass, and to determine what type of training produces greater adaptations in postmenopausal women. Methods: A total of 38 women completed the study (Clinical Gov database ID: NCT01966562). Participants were randomly assigned to one of the study groups: whole-body vibration group (WBVG), multi-component training group (MTG), or control group (CG). The experimental groups performed a progressive 24-week training (3 sessions/week) program. Bone mineral density (BMD) and bone mineral content (BMC) at the lumbar spine and femoral neck were assessed by Dual-energy X-ray absorptiometry. Results: Significantly and clinically relevant increases in lumbar spine bone mass (BMD: F = 3.29; p = 0.03; +5.15%; BMC: F = 2.90; p = 0.05; +10.58%) were observed in WBVG. MTG showed clinically important pre-post-changes on lumbar spine BMC (+7.78%), although there was no statistical significance (F = 1.97; p = 0.14). At the femoral neck, no statistically significant increases on bone mass were obtained in either training group. No changes were obtained in any variable in the CG. Additionally, no statistically significant differences were found between groups. Conclusion: The results indicated that 24 weeks of supervised WBV and MT may counteract the rapid loss of bone mass after the cessation of menstruation, thus improving postmenopausal women bone health. However, in the absence of statistically significant differences between groups, it is not possible to determine which training protocol produces greater adaptations. Clinical Trial Registration: www.ClinicalTrialsgov, identifier: NCT01966562.

Nutrient Intake Prior to Exercise Is Necessary for Increased Osteogenic Marker Response in Diabetic Postmenopausal Women

Type 2 diabetes increases bone fracture risk in postmenopausal women. Usual treatment with anti-resorptive bisphosphonate drugs has some undesirable side effects, which justified our interest in the osteogenic potential of nutrition and exercise. Since meal eating reduces bone resorption, downhill locomotion increases mechanical stress, and brief osteogenic responsiveness to mechanical stress is followed by several hours of refractoriness, we designed a study where 40-min of mechanical stress was manipulated by treadmill walking uphill or downhill. Exercise preceded or followed two daily meals by one hour, and the meals and exercise bouts were 7 hours apart. Fifteen subjects each performed two of five trials: No exercise (SED), uphill exercise before (UBM) or after meals (UAM), and downhill exercise before (DBM) or after meals (DAM). Relative to SED trial, osteogenic response, defined as the ratio of osteogenic C-terminal propeptide of type I collagen (CICP) over bone-resorptive C-terminal telopeptide of type-I collagen (CTX) markers, increased in exercise-after-meal trials, but not in exercise-before-meal trials. CICP/CTX response rose significantly after the first exercise-after-meal bout in DAM, and after the second one in UAM, due to a greater CICP rise, and not a decline in CTX. Post-meal exercise, but not the pre-meal exercise, also significantly lowered serum insulin response and homeostatic model (HOMA-IR) assessment of insulin resistance.

Vibration enhances osteoclastogenesis by inducing RANKL expression via NF-κB signaling in osteocytes

To shorten the duration of orthodontic treatment it is important not only to reduce risks such as dental caries, periodontal disease, and root resorption, but also to decrease pain and discomfort caused by a fixed appliance. Several studies have investigated the effect of vibration applied to fixed appliances to accelerate tooth movement. Although it was reported that vibration accelerates orthodontic tooth movement by enhancing alveolar bone resorption, the underlying cellular and molecular mechanisms remain unclear. In this study, we investigated the effects of vibration on osteoclastogenesis in vitro and in vivo. Vibration applied to pre-osteoclast cell line RAW264.7 cells enhanced cell proliferation but did not affect their differentiation into osteoclasts. Osteocytes in bone are known to be mechanosensitive and to act as receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL). Therefore, in the present study, vibration was applied to cells from the osteocyte-like cell line MLO-Y4. In MLO-Y4 cells, vibration induced phosphorylation of the inhibitor of NF-κB (IκB) and caused nuclear localization of NF-κB p65. Additionally, vibration increased RANKL mRNA expression, but did not affect osteoprotegerin (OPG) mRNA expression in MLO-Y4 cells, thus resulting in an increased RANKL/OPG ratio. Consistent with these findings, vibration applied during experimental tooth movement increased NF-κB activation and RANKL expression in osteocytes on the compression side of alveolar bone in vivo, whereas vibration had no such effects on the tension side. Furthermore, in a co-culture of MLO-Y4 cells and RAW264.7 cells, vibration applied to MLO-Y4 cells enhanced osteoclastogenesis. These findings suggest that vibration could accelerate orthodontic tooth movement by enhancing osteoclastogenesis through increasing the number of pre-osteoclasts and up-regulating RANKL expression in osteocytes on the compression side of alveolar bone via NF-κB activation.

Three-dimensional cell culture can be regulated by vibration: low-frequency vibration increases the size of olfactory ensheathing cell spheroids

Background

Olfactory ensheathing cell (OEC) transplantation is emerging as a promising therapy for spinal cord injuries. However, outcomes are inconsistent, and the method needs improvement. Currently, cells are injected into the injury site as a suspension, and often fail to form a three-dimensional (3D) network crucial for both survival of the transplanted cells, and for regeneration of severed axons. 3D culture systems are therefore likely to improve the method. Of the many 3D culture systems available, the spheroid-producing naked liquid marble (NLM) technique is particularly advantageous compared to other platforms as it rapidly generates cell spheroids which can easily be extracted for further handling. To improve production of the spheroids, we designed and tested a device which allows fine control over vibrational stimuli to liquid marble cell cultures. We applied vibrational frequencies of 20, 60, and 80 Hz with consistent amplitude to NLM containing OECs and assessed the size and number of the 3D cell spheroids generated as well as the migratory capacity of cells cultured in the vibrated spheroids.

Results

Vibrating the NLMs led to fewer and dramatically larger spheroids in comparison to non-vibrated NLMs. Of the frequencies tested, 60 Hz caused over 70-fold increase in spheroid volume. When transferred to a culture plate, the larger spheroids retained their structure after 72 h in culture, and cells that migrated out of the spheroids covered a significantly larger area compared to cells migrating out of spheroids formed at all the other frequencies tested.

Conclusions

We have shown that vibration can be used to regulate the formation of cell spheroids in NLM cultures. The ability to modulate the size of spheroids is useful for a range of 3D cell culture models and for preparing cells for in vivo transplantation.

Lower Body Acceleration and Muscular Responses to Rotational and Vertical Whole-Body Vibration at Different Frequencies and Amplitudes

Aim:

The aim of this study was to characterize acceleration transmission and neuromuscular responses to rotational vibration (RV) and vertical vibration (VV) at different frequencies and amplitudes.

Methods:

Twelve healthy males completed 2 experimental trials (RV vs VV) during which vibration was delivered during either squatting (30°; RV vs VV) or standing (RV only) with 20, 25, and 30 Hz, at 1.5 and 3.0 mm peak-to-peak amplitude. Vibration-induced accelerations were assessed with triaxial accelerometers mounted on the platform and bony landmarks at ankle, knee, and lumbar spine.

Results:

At all frequency/amplitude combinations, accelerations at the ankle were greater during RV (all P < .03) with the greatest difference observed at 30 Hz, 1.5 mm. Transmission of RV was also influenced by body posture (standing vs squatting, P < .03). Irrespective of vibration type, vibration transmission to all skeletal sites was generally greater at higher amplitudes but not at higher frequencies, especially above the ankle joint. Acceleration at the lumbar spine increased with greater vibration amplitude but not frequency and was highest with RV during standing.

Conclusions/Implications:

The transmission of vibration during whole-body vibration (WBV) is dependent on intensity and direction of vibration as well as body posture. For targeted mechanical loading at the lumbar spine, RV of higher amplitude and lower frequency vibration while standing is recommended. These results will assist with the prescription of WBV to achieve desired levels of mechanical loading at specific sites in the human body.

Loading of the hip and knee joints during whole body vibration training

During whole body vibrations, the total contact force in knee and hip joints consists of a static component plus the vibration-induced dynamic component. In two different cohorts, these forces were measured with instrumented joint implants at different vibration frequencies and amplitudes. For three standing positions on two platforms, the dynamic forces were compared to the static forces, and the total forces were related to the peak forces during walking. A biomechanical model served for estimating muscle force increases from contact force increases. The median static forces were 122% to 168% (knee), resp. 93% to 141% (hip), of the body weight. The same accelerations produced higher dynamic forces for alternating than for parallel foot movements. The dynamic forces individually differed much between 5.3% to 27.5% of the static forces in the same positions. On the Powerplate, they were even close to zero in some subjects. The total forces were always below 79% of the forces during walking. The dynamic forces did not rise proportionally to platform accelerations. During stance (Galileo, 25 Hz, 2 mm), the damping of dynamic forces was only 8% between foot and knee but 54% between knee and hip. The estimated rises in muscle forces due to the vibrations were in the same ranges as the contact force increases. These rises were much smaller than the vibration-induced EMG increases, reported for the same platform accelerations. These small muscle force increases, along with the observation that the peak contact and muscle forces during vibrations remained far below those during walking, indicate that dynamic muscle force amplitudes cannot be the reason for positive effects of whole body vibrations on muscles, bone remodelling or arthritic joints. Positive effects of vibrations must be caused by factors other than raised forces amplitudes.

Effect of the application of high-frequency mechanical vibration on tooth length concurrent with orthodontic treatment using clear aligners: A retrospective study

OBJECTIVES:

To evaluate the possible change in teeth lengths as an indicator of orthodontically induced tooth root resorption (OITRR) after high-frequency mechanical vibration (HFV) treatment concurrent with Invisalign Smart Track® aligners as evaluated by cone beam computed tomography (CBCT).

MATERIALS AND METHODS:

The sample, composed of 30 patients with an average age of 26 ± 11 years and Class I malocclusion with an initial anterior crowding ranging from 3 to 5 mm, was divided equally into two groups; Group I received adjunctive high-frequency mechanical vibration (HFV); Group II, the control, did not receive adjunctive mechanical treatment. The maxillary incisor's teeth lengths were measured using Mimics software before (T1) and after (T2) treatment. All data were analyzed using Student's t-test. Reliability testing was completed by randomly selecting 10 patients’ CBCTs, and their teeth lengths were measured twice by the same investigator over a 15-day interval and compared confirming intra-operator accuracy.

RESULTS:

The control group showed a statistically significant decrease in tooth lengths compared to the HFV group which showed nonstatistically significant change of tooth lengths.

CONCLUSION:

Patients treated with HFV showed minimum tooth length changes after treatment, which may indicate that HFV can reduce OITRR with treatment using clear aligners.

Effects of Teriparatide and Vibration on Bone Mass and Bone Strength in People with Bone Loss and Spinal Cord Injury: A Randomized, Controlled Trial

Spinal cord injury (SCI) is associated with marked bone loss and an increased risk of fracture. We randomized 61 individuals with chronic SCI and low bone mass to receive either teriparatide 20 μg/d plus sham vibration 10 min/d (n = 20), placebo plus vibration 10 min/d (n = 20), or teriparatide 20 μg/d plus vibration 10 min/d (n = 21). Patients were evaluated for 12 months; those who completed were given the opportunity to participate in an open-label extension where all participants (n = 25) received teriparatide 20 μg/d for an additional 12 months and had the optional use of vibration (10 min/d). At the end of the initial 12 months, both groups treated with teriparatide demonstrated a significant increase in areal bone mineral density (aBMD) at the spine (4.8% to 5.5%). The increase in spine aBMD was consistent with a marked response in serum markers of bone metabolism (ie, CTX, P1NP, BSAP), but no treatment effect was observed at the hip. A small but significant increase (2.2% to 4.2%) in computed tomography measurements of cortical bone at the knee was observed in all groups after 12 months; however, the magnitude of response was not different amongst treatment groups and improvements to finite element-predicted bone strength were not observed. Teriparatide treatment after the 12-month extension resulted in further increases to spine aBMD (total increase from baseline 7.1% to 14.4%), which was greater in patients initially randomized to teriparatide. Those initially randomized to teriparatide also demonstrated 4.4% to 6.7% improvements in hip aBMD after the 12-month extension, while all groups displayed increases in cortical bone measurements at the knee. To summarize, teriparatide exhibited skeletal activity in individuals with chronic SCI that was not augmented by vibration stimulation. Without additional confirmatory data, the location-specific responses to teriparatide would not be expected to provide clinical benefit in this population. © 2018 American Society for Bone and Mineral Research.

The effect of low-magnitude, high-frequency vibration on poly(ethylene glycol)-microencapsulated mesenchymal stem cells

Low-magnitude, high-frequency vibration has stimulated osteogenesis in mesenchymal stem cells when these cells were cultured in certain types of three-dimensional environments. However, results of osteogenesis are conflicting with some reports showing no effect of vibration at all. A large number of vibration studies using three-dimensional scaffolds employ scaffolds derived from natural sources. Since these natural sources potentially have inherent biochemical and microarchitectural cues, we explored the effect of low-magnitude, high-frequency vibration at low, medium, and high accelerations when mesenchymal stem cells were encapsulated in poly(ethylene glycol) diacrylate microspheres. Low and medium accelerations enhanced osteogenesis in mesenchymal stem cells while high accelerations inhibited it. These studies demonstrate that the isolated effect of vibration alone induces osteogenesis.

Whole-body vibration training and bone health in postmenopausal women: A systematic review and meta-analysis

BACKGROUND

The aims of the present systematic review and meta-analysis were to evaluate published, randomized controlled trials that investigate the effects on whole-body vibration (WBV) training on total, femoral neck, and lumbar spine bone mineral density (BMD) in postmenopausal women, and identify the potential moderating factors explaining the adaptations to such training.

METHODS

From a search of electronic databases (PubMed, Web of Science, and Cochrane) up until September 2017, a total 10 studies with 14 WBV groups met the inclusion criteria. Three different authors tabulated, independently, the selected indices in identical predetermined forms. The methodological quality of all studies was evaluated according to the modified PEDro scale. For each trial, differences within arms were calculated as mean differences (MDs) and their 95% confidence intervals between pre- and postintervention values. The effects on bone mass between exercise and control groups were also expressed as MDs. Both analyses were performed in the total sample and in a specific class of postmenopausal women younger than 65 years of age (excluding older women).

RESULTS

The BMD of 462 postmenopausal women who performed WBV or control protocol was evaluated. Significant pre-post improvements in BMD of the lumbar spine were identified following WBV protocols (P = .03). Significant differences in femoral neck BMD (P = .03) were also found between intervention and control groups when analyzing studies that included postmenopausal women younger than 65 years.

CONCLUSIONS

WBV is an effective method to improve lumbar spine BMD in postmenopausal and older women and to enhance femoral neck BMD in postmenopausal women younger than 65 years.

Whole body vibration with rest days could improve bone quality of distal femoral metaphysis by regulating trabecular arrangement

Low-magnitude, high-frequency vibration (LMHFV) with rest days (particularly seven rest days) was considerably effective in improving the morphological and mechanical properties of rat proximal femur. However, current knowledge is limited regarding the possible benefit of this mechanical regimen to other bone sites and whether the optimal rest days are the same. This study followed our previous experiment on LMHFV loading with rest days for three-month-old male Wistar rats. The experiment involved seven groups, namely, vibrational loading for X day followed with X day rest (X=1, 3, 5, 7), daily vibrational loading, tail suspension and baseline control. Micro-computed tomography (micro-CT) scanning was used to evaluate the microarchitecture of the distal femoral trabecular bone. Micro-CT image-based microfinite element analysis was performed for each distal femoral metaphysis. LMHFV with rest days substantially changed the trabecular arrangement from remarkably plate-like to rod-like. Vibrational loading with 1 day rest was substantially effective in improving the architecture and apparent- and tissuelevel mechanical properties of the rat distal femoral metaphysis. This study may provide an improved understanding of the sitespecific responses of bone tissue to LMHFV with rest days for a substantially effective therapy of a targeted bone site.

Iliac and mandible osteoblasts exhibit varied responses to LMHF vibration

The facial and long bones have distinct developmental origins, structures, and cellular compositions. This study aimed to compare the in vitro responses of human mandible and long bone osteoblasts to low-magnitude, high-frequency (LMHF) mechanical vibration in terms of expression of mediators of bone remodeling. Osteoblast-like cell cultures were prepared from iliac crest and mandibular bone specimens from three individuals and cultured in osteogenic induction media. Induction of mature osteoblastic phenotypes was confirmed by analysis of DNA content, alkaline phosphatase activity and gene expression every 3 days for 27 days. Based on gene expression, mature osteoblasts formed by day 15 of induction culture. After 15 days of culture in induction media, mature osteoblasts were subjected to vibration (0, 30, or 60 Hz) for 30 min every 24 h. After 48 h, RANKL, OPG, IL-1β, IL-6 and TGF-β gene, and protein expression were determined by real-time PCR analysis of total cellular mRNA and ELISAs of the cell supernatants. Both iliac and mandible osteoblasts responded to LMHF vibration: IL-1β and RANKL mRNA were downregulated and IL-6 mRNA was upregulated. However, TGF- β mRNA was unaltered and OPG mRNA was upregulated in iliac osteoblasts, whereas both TGF-β and OPG mRNA were downregulated in mandible osteoblasts. As a result, LMHF reduced the RANKL/OPG mRNA ratio in iliac osteoblasts but did not alter the RANKL/OPG mRNA ratio in mandible osteoblasts. This study suggests mature iliac osteoblasts exhibit a more potent anti-resorptive response to vibration, while this tendency was not obviously apparent in mature mandible osteoblasts.

Whole Body Vibration Exposure on Markers of Bone Turnover, Body Composition, and Physical Functioning in Breast Cancer Patients Receiving Aromatase Inhibitor Therapy: A Randomized Controlled Trial

Introduction: Women with breast cancer are often prescribed aromatase inhibitors, which can cause rapid loss of bone mass leading to significant potential for morbidity. Vibration training has been shown to be helpful in reducing bone turnover in postmenopausal women without cancer. Aim: To examine the effect of vibration stimulus on markers of bone turnover in breast cancer patients receiving aromatase inhibitors. Methods: Thirty-one breast cancer survivors undergoing treatment with aromatase inhibitors were randomized to vibration stimulus (n = 14) or usual care control (n = 17). Low-frequency and low-magnitude vibration stimulus (27-32 Hz, 0.3g) was delivered in supervised sessions via standing on a vibration platform for 20 minutes, 3 times per week for 12 weeks. The primary outcome was blood markers of bone resorption (serum N-telopeptide X/creatine) and formation (serum type 1 procollagen N-terminal propeptide; P1NP). Other study outcomes body composition as well as measures of physical functioning. Outcomes were compared between groups using analysis of covariance adjusted for baseline values as well as time on aromatase inhibitors. Outcomes: On average, participants were 61.5 years old and overweight (ie, body mass index = 28.5 kg/m²). Following vibration training, there was no significant difference between groups for bone resorption (adjusted group difference 0.5, P = .929) or formation (adjusted group difference 5.3, P = .286). There were also no changes in any measure of physical functioning body composition. Conclusions: Short-term low-magnitude vibration stimulus does not appear to be useful for reducing markers of bone turnover secondary to aromatase inhibitors in breast cancer patients; nor is it useful in improving physical function or symptoms. However, further investigations with larger samples and higher doses of vibration are warranted. Trial Registration: Australian and New Zealand Clinical Trials Registry (ACTRN12611001094965).

A systematic review of the exercise effect on bone health: the importance of assessing mechanical loading in perimenopausal and postmenopausal women

OBJECTIVE

The aims of this systematic review were to determine the general effects of exercise on areal bone mineral density (BMD) in perimenopausal and postmenopausal women, and to provide information on the most suitable bone-loading exercise regimens that may improve bone health in this population group.

METHODS

A computerized, systematic literature search was performed in the electronic databases PubMed, Web of Science, CINAHL, SPORTDiscus, and The Cochrane Library, from January 2005 to November 2015, to identify all randomized controlled trials related to exercise in perimenopausal and postmenopausal women. The initial search identified 915 studies, with a final yield of 10 studies. Only randomized controlled trials that examined the effects of exercise programs longer than 24 weeks in women aged 35 to 70 years were included. The 10 studies quantified at least BMD and described training variables adequately (training period, frequency, volume, intensity).

RESULTS

Ten studies with moderate quality evidence (6.4 ± 1.8 points, range 4-9) were included. Significant changes in lumbar and femoral neck BMD were found mainly with high-impact exercise and whole body vibration interventions.

CONCLUSIONS

While training effects must be interpreted with caution because of the heterogeneity of the protocols and exercises performed, this systematic review confirmed the effectiveness of impact exercises combined with other forms of training (vibration or strength training) to preserve BMD in perimenopausal and postmenopausal women. Despite the results possibly not representing a general dose-response relationship, we highlight the importance of quantifying loading intensity and frequency by means of accelerometry as these parameters are determinants for bone adaptation.

Estrogen receptor α- (ERα), but not ERβ-signaling, is crucially involved in mechanostimulation of bone fracture healing by whole-body vibration

Mechanostimulation by low-magnitude high frequency vibration (LMHFV) has been shown to provoke anabolic effects on the intact skeleton in both mice and humans. However, experimental studies revealed that, during bone fracture healing, the effect of whole-body vibration is profoundly influenced by the estrogen status. LMHFV significantly improved fracture healing in ovariectomized (OVX) mice being estrogen deficient, whereas bone regeneration was significantly reduced in non-OVX, estrogen-competent mice. Furthermore, estrogen receptors α (ERα) and β (ERβ) were differentially expressed in the fracture callus after whole-body vibration, depending on the estrogen status. Based on these data, we hypothesized that ERs may mediate vibration-induced effects on fracture healing. To prove this hypothesis, we investigated the effects of LMHFV on bone healing in mice lacking ERα or ERβ. To study the influence of the ER ligand estrogen, both non-OVX and OVX mice were used. All mice received a femur osteotomy stabilized by an external fixator. Half of the mice were sham-operated or subjected to OVX 4 weeks before osteotomy. Half of each group received LMHFV with 0.3 g and 45 Hz for 20 min per day, 5 days per week. After 21 days, fracture healing was evaluated by biomechanical testing, μCT analysis, histomorphometry and immunohistochemistry. Absence of ERα or ERβ did not affect fracture healing in sham-treated mice. Wildtype (WT) and ERβ-knockout mice similarly displayed impaired bone regeneration after OVX, whereas ERα-knockout mice did not. Confirming previous data, in WT mice, LMHFV negatively affected bone repair in non-OVX mice, whereas OVX-induced compromised healing was significantly improved by vibration. In contrast, vibrated ERα-knockout mice did not display significant differences in fracture healing compared to non-vibrated animals, both in non-OVX and OVX mice. Fracture healing in ERβ-knockout mice was similarly affected by LMHFV as in WT mice. These results suggest that ERα-signaling may be crucial for vibration-induced effects on fracture healing, whereas ERβ-signaling may play a minor role.

Effect of supplemental vibration on orthodontic treatment with aligners: A randomized trial

INTRODUCTION

Supplemental vibration has been reported to accelerate orthodontic tooth movement and reduce discomfort. Our purpose was to investigate the effects of AcceleDent on Invisalign treatment. This randomized clinical trial was carried out in 2 orthodontic private practices with a 1:1 allocation ratio.

METHODS

Adult patients who were beginning their orthodontic treatment were randomly allocated to either an active (A) or a sham (B) AcceleDent Aura device (OrthoAccel Technologies, Inc. Houston, TX). All patients were placed on a 1-week aligner change regimen, and fit was evaluated every 3 weeks. The outcomes were the ability to complete the initial set of aligners and the incisor irregularity measurements for those who completed their regimen of aligners. In addition, aligner compliance, pain levels, and oral health-related quality of life data were gathered from questionnaires. The subjects, investigators, and assessors were all blinded to the treatment arms.

RESULTS

Twenty-seven subjects were randomized into 2 groups (A and B), 1 subject discontinued treatment, and 13 subjects were analyzed in each group. The Fisher exact test showed no significant difference in completion rates between the 2 groups (group A, 77%; group B, 85%; P = 1). Independent-sample t tests showed no significant difference between the final irregularity index or change in irregularity index between the 2 groups. Compliance was similar in both groups. The Wilcoxon rank sum test showed minimal differences in pain levels. Quality of life responses were similar in both groups. No serious harm was observed.

CONCLUSIONS

We found no evidence that the AcceleDent Aura device impacts the ability to complete a series of aligners with a 1-week change regimen or the final alignment achieved in adult patients. It also had no significant effect on the reduction of orthodontic pain or oral health-related quality of life parameters when used with Invisalign.

Effect of high-frequency loading and parathyroid hormone administration on peri-implant bone healing and osseointegration

The objective of this study is to examine the effect of low-magnitude, high-frequency (LMHF) loading, and anti-osteoporosis medications such as parathyroid hormone (PTH) and bisphosphonates on peri-implant bone healing in an osteoporosis model, and to assess their combined effects on these processes. Thirteen-week-old ovariectomized rats (n = 44) were divided into three groups: PTH, alendronate, and saline. After 3 weeks of drug administration, titanium implants were inserted into the tibiae. Each group was subdivided into two groups: with or without LMHF loading via whole-body vibration (50 Hz at 0.5 g, 15 min per day, 5 days per week). Rats were killed 4 weeks following implantation. Removal torque test, micro-CT analyses (relative gray (RG) value, water = 0, and implant = 100), and histomorphometric analyses (bone-to-implant contact (BIC) and peri-implant bone formation (bone volume/tissue volume (BV/TV))) were performed. Removal torque values and BIC were significantly differed by loading and drug administration (ANOVA). Post hoc analysis showed that PTH-treated groups were significantly higher than the other drug-treated groups. BV/TV was significantly enhanced by PTH administration. In cortical bone, RG values were significantly increased by loading. In trabecular bone, however, RG values were significantly increased by PTH administration. These findings suggest that LMHF loading and PTH can act locally and additively on the bone healing process, improving the condition of implant osseointegration.

Whole-body vibration and administration of a hormone used to treat osteoporosis can enhance bone healing at the site of a titanium implant. Toru Ogawa of Tohoku University Graduate School of Dentistry in Sendai, Japan, and colleagues gave anti-osteoporosis medications, either parathyroid hormone or the bisphosphonate drug alendronate, to female rat models of osteoporosis. After three weeks of drug administration or a saline control, the researchers inserted titanium implants into the rats’ leg bones. Half the rats were then exposed to whole-body vibration, which applies low-magnitude, high-frequency mechanical forces. A multitude of tests showed that parathyroid hormone improved bone healing at the implant more than alendronate or saline did. The vibrational stimulus further increased the healing. The findings suggest that these treatments could aid in oral bone healing for patients receiving dental implants.

Low-Intensity Vibration Improves Muscle Healing in a Mouse Model of Laceration Injury

Recovery from traumatic muscle injuries is typically prolonged and incomplete, leading to impaired muscle and joint function. We sought to determine whether mechanical stimulation via whole-body low-intensity vibration (LIV) could (1) improve muscle regeneration and (2) reduce muscle fibrosis following traumatic injury. C57BL/6J mice were subjected to a laceration of the gastrocnemius muscle and were treated with LIV (0.2 g at 90 Hz or 0.4 g at 45 Hz for 30 min/day) or non-LIV sham treatment (controls) for seven or 14 days. Muscle regeneration and fibrosis were assessed in hematoxylin and eosin or Masson's trichrome stained muscle cryosections, respectively. Compared to non-LIV control mice, the myofiber cross-sectional area was larger in mice treated with each LIV protocol after 14 days of treatment. Minimum fiber diameter was also larger in mice treated with LIV of 90 Hz/0.2 g after 14 days of treatment. There was also a trend toward a reduction in collagen deposition after 14 days of treatment with 45 Hz/0.4 g (p = 0.059). These findings suggest that LIV may improve muscle healing by enhancing myofiber growth and reducing fibrosis. The LIV-induced improvements in muscle healing suggest that LIV may represent a novel therapeutic approach for improving the healing of traumatic muscle injuries.

Vibration loading promotes osteogenic differentiation of bone marrow-derived mesenchymal stem cells via p38 MAPK signaling pathway

Low magnitude high frequency vibration (LMHFV) exhibits effectively anabolic effects on the bone tissue, and can promote osteogenic differentiation of mesenchymal stem cells (MSCs) in vitro. The role of p38 MAPK signaling in LMHFV-induced osteogenesis remains unclear. In this current study, LMHFV loading was applied to BMSCs in vitro, and cell proliferation, alkaline phosphatase (ALP), matrix mineralization, as well as osteogenic genes expression were assayed. The mechanism of mechanical signal transduction was analysed using PCR array, qRT-PCR and Western blot. LMHFV increased cell proliferation in the growth medium, while inhibited proliferation in the osteogenic medium. ALP activity, matrix mineralization and osteogenic genes expression of Runx2, Col-I, ALP, OPN and OC were increased by LMHFV. p38 and MKK6 genes expression, and p38 phosphorylation were promoted in LMHFV-induced osteogenesis. Inhibition of p38 MAPK with SB203580 and targeted p38 siRNA blunted the increased ALP activity and osteogenic genes expression by LMHFV. These findings suggest that LMHFV promotes osteogenic differentiation of BMSCs, and p38 MAPK signaling shows an important function in LMHFV-induced osteogenesis.

Low-intensity vibration increases cartilage thickness in obese mice

Obesity is associated with an elevated risk of osteoarthritis (OA). We examined here whether high fat diet administered in young mice, compromised the attainment of articular cartilage thickness. Further, we sought to determine if low-intensity vibration (LIV) could protect the retention of articular cartilage in a mouse model of diet-induced obesity. Five-week-old, male, C57BL/6 mice were separated into three groups (n = 10): Regular diet (RD), High fat diet (HF), and HF + LIV (HFv; 90 Hz, 0.2g, 30 min/d, 5 d/w) administered for 6 weeks. Additionally, an extended HF diet study was run for 6 months (LIV at 15 m/d). Articular cartilage and subchondral bone morphology, and sulfated GAG content were quantified using contrast agent enhanced μCT and histology. Gene expression within femoral condyles was quantified using real-time polymerase chain reaction. Contrary to our hypothesis, HF cartilage thickness was not statistically different from RD. However, LIV increased cartilage thickness compared to HF, and the elevated thickness was maintained when diet and LIV were extended into adulthood. RT-PCR analysis showed a reduction of aggrecan expression with high fat diet, while application of LIV reduced the expression of degradative MMP-13. Further, long-term HF diet resulted in subchondral bone thickening, compared to RD, providing early evidence of OA pathology-LIV suppressed the thickening, such that levels were not significantly different from RD. These data suggest that dynamic loading, via LIV, protected the retention of cartilage thickness, potentially resulting in joint surfaces better suited to endure the risks of elevated loading that parallel obesity. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:751-759, 2018.

Efficacy of mechano-acoustic vibration on strength, pain, and function in poststroke rehabilitation: a pilot study

BACKGROUND

Vibration therapy may be used to help cortical reorganization after stroke as it can cause different adaptive metabolic and mechanical effects.

OBJECTIVE

This study examined whether the application of mechano-acoustic vibration on upper limb muscles could induce changes in range of motion (ROM), function, pain, and grip strength in individuals with chronic stroke.

METHODS

Out of 52 individuals post stroke with upper limb spasticity who were eligible,16 received mechano-acoustic vibration therapy (ViSS device) 3 times weekly for 12 sessions. The frequency of vibration was set to 300 Hz for 30 minutes. The treated muscles were the extensor carpi radialis longus and brevis and triceps brachii during voluntary contraction. All participants were evaluated in both upper limbs before (T0) and at the end (T1) of treatment with a dynamometer (hand grip strength), Modified Ashworth Scale, QuickDASH, FIM score, Fugl-Meyer scale, Verbal Numerical Rating Scale of pain, and Jebsen-Taylor Hand Function Test.

RESULTS

After 4 weeks, hand grip power had improved and pain and spasticity had decreased. Improvements were recorded for all parameters and were considered statistically significant.

CONCLUSIONS

Application of vibratory stimuli to a muscle can increase the motor-evoked potential recorded from the muscle, suggesting an enhancement of corticospinal excitability. Low amplitude, high-frequency vibration treatment (300 Hz) can significantly decrease tone and pain and improve strength in upper limb of hemiplegic individuals, when applied for 30 minutes, 3 times a week over 4 weeks.

Strain and Vibration in Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiating into any mesenchymal tissue, including bone, cartilage, muscle, and fat. MSC differentiation can be influenced by a variety of stimuli, including environmental and mechanical stimulation, scaffold physical properties, or applied loads. Numerous studies have evaluated the effects of vibration or cyclic tensile strain on MSCs towards developing a mechanically based method of differentiation, but there is no consensus between studies and each investigation uses different culture conditions, which also influence MSC fate. Here we present an overview of the response of MSCs to vibration and cyclic tension, focusing on the effect of various culture conditions and strain or vibration parameters. Our review reveals that scaffold type (e.g., natural versus synthetic; 2D versus 3D) can influence cell response to vibration and strain to the same degree as loading parameters. Hence, in the efforts to use mechanical loading as a reliable method to differentiate cells, scaffold selection is as important as method of loading.

Low-1 level mechanical vibration improves bone microstructure, tissue mechanical properties and porous titanium implant osseointegration by promoting anabolic response in type 1 diabetic rabbits

Type 1 diabetes mellitus (T1DM) is associated with reduced bone mass, increased fracture risk, and impaired bone defect regeneration potential. These skeletal complications are becoming important clinical challenges due to the rapidly increasing T1DM population, which necessitates developing effective treatment for T1DM-associated osteopenia/osteoporosis and bone trauma. This study aims to investigate the effects of whole-body vibration (WBV), an easy and non-invasive biophysical method, on bone microstructure, tissue-level mechanical properties and porous titanium (pTi) osseointegration in alloxan-diabetic rabbits. Six non-diabetic and twelve alloxan-treated diabetic rabbits were equally assigned to the Control, DM, and DM with WBV stimulation (WBV) groups. A cylindrical drill-hole defect was established on the left femoral lateral condyle of all rabbits and filled with a novel non-toxic Ti2448 pTi. Rabbits in the WBV group were exposed to 1h/day WBV (0.3g, 30Hz) for 8weeks. After sacrifice, the left femoral condyles were harvested for histological, histomorphometric and nanoindentation analyses. The femoral sample with 2-cm height above the defect was used for qRT-PCR analysis. The right distal femora were scanned with μCT. We found that all alloxan-treated rabbits exhibited hyperglycemia throughout the experimental period. WBV inhibited the deterioration of cancellous and cortical bone architecture and tissue-level mechanical properties via μCT, histological and nanoindentation examinations. T1DM-induced reduction of bone formation was inhibited by WBV, as evidenced by elevated serum OCN and increased mineral apposition rate (MAR), whereas no alteration was observed in bone resorption marker TRACP5b. WBV also stimulated more adequate ingrowths of mineralized bone tissue into pTi pore spaces, and improved peri-implant bone tissue-level mechanical properties and MAR in T1DM bone defects. WBV mitigated the reductions in femoral BMP2, OCN, Wnt3a, Lrp6, and β-catenin and inhibited Sost mRNA expression but did not alter RANKL or RANK gene expression in T1DM rabbits. Our findings demonstrated that WBV improved bone architecture, tissue-level mechanical properties, and pTi osseointegration by promoting canonical Wnt signaling-mediated skeletal anabolic response. This study not only advances our understanding of T1DM skeletal sensitivity in response to external mechanical cues but also offers new treatment alternatives for T1DM-associated osteopenia/osteoporosis and osseous defects in an economic and highly efficient manner.

Effect of combined treatment with focused mechano-acoustic vibration and pharmacological therapy on bone mineral density and muscle strength in post-menopausal women

Introduction

Osteoporosis is a systemic disease of the skeleton characterized by a reduction in bone mass and alterations in microarchitecture accompanied by increase in fracture risk, with a relevant decline in quality of life and important social, economic, and health implications, representing one of the most common causes of disability and a major financial item of health cost in many Countries. The best therapy for osteoporosis is prevention, consisting in measures to avoid or slow the onset of the disease. Treatment includes measures aimed at osteoporotic individuals, with or without previous fractures and a high risk of a first or additional fracture.

Method

We enrolled thirty post-menopausal osteoporotic women, allocated in the first group underwent a 6-month personalized drug therapy and focused mechanoacoustic vibration (2 sessions per week, each lasting 15 minutes); women allocated in the second group underwent only 6-month personalized drug therapy. Patients were evaluated performing dual-energy X-ray absorptiometry (DXA) and isokinetic machine evaluation, and administration of Tinetti scale and ECOS-16 questionnaire.

Result

Show improvement of bone mineral density (BMD) and T-score at the lumbar spine and femoral neck, handgrip strength and isokinetic strength of the knee estensors, balance and gait, and quality of life.

Conclusion

Hence, the combined treatment with focused mechano-acoustic vibration and pharmacological therapy has a beneficial effect on BMD and T-score as well as on the muscle strength and quality of life of osteoporotic subjects.

Bone mineral density in children with acute lymphoblastic leukemia

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) can develop reduced bone mineral density (BMD). However, data from patients who received treatment on a frontline regimen without cranial irradiation are limited, and no genome-wide analysis has been reported.

METHODS

Lumbar BMD was evaluated by quantitative computed tomography at diagnosis, after 120 weeks of continuation therapy, and after 2 years off therapy in pediatric patients with ALL (ages 2-18 years at diagnosis) who were treated on the St. Jude Total XV Protocol. Clinical, pharmacokinetic, and genetic risk factors associated with decreased BMD Z-scores were evaluated.

RESULTS

The median BMD Z-score in 363 patients was 0.06 at diagnosis, declined to -1.08 at week 120, but partly recovered to -0.72 after 2 years off therapy; BMD in patients with low BMD Z-scores at diagnosis remained low after therapy. Older age (≥10 years vs 2-9.9 years at diagnosis; P < .001), a higher BMD Z-score at diagnosis (P = .001), and a greater area under the plasma drug concentration-time curve for dexamethasone in weeks 7 and 8 of continuation therapy (P = .001) were associated with a greater decrease in BMD Z-score from diagnosis to week 120. Single-nucleotide polymorphisms in 2 genes important in osteogenesis and bone mineralization (COL11A1 [reference single-nucleotide polymorphism rs2622849]; P = 2.39 × 10^-7 ] and NELL1 [rs11025915]; P = 4.07 × 10^-6 ]) were associated with a decreased BMD Z-score. NELL1 (P = .003) also was associated with a greater dexamethasone area under the plasma drug concentration-time curve.

CONCLUSIONS

BMD Z-scores decreased during therapy, especially in patients who had clinical, pharmacokinetic, and genetic risk factors. Early recognition of BMD changes and strategies to optimize bone health are essential. Cancer 2018;124:1025-35. © 2017 American Cancer Society.