Vibration therapy: clinical applications in bone

The Clinical Utility of Whole Body Vibration: A Review of the Different Types and Dosing for Application in Metabolic Diseases

Whole body vibration (WBV) is an innovative exercise mimetic that utilizes a vibrating platform to transmit mechanical vibrations throughout the body. WBV has been a popular area of research in recent years due to its potential physiological and therapeutic benefits in both health and disease. The utility of WBV is rooted in the various parameters (i.e., frequency, amplitude, duration) that affect the overall dose of vibration delivered to the body. Each type of WBV, coupled with these aforementioned parameters, should be considered when evaluating the use of WBV in the clinical setting. Thus, the purpose of this review is to provide an overview of recent literature detailing the different types of WBV, the various parameters that contribute to WBV efficacy, and the evidence of WBV in metabolic disease. A systematic search was conducted using Medline, Embase, Cochrane, CINAHL, and PubMed. All types of study designs were considered, with exclusions made for animal studies, duplicates, and study protocols without data. Thirty-four studies were included. In conclusion, as a modern exercise mimetic with therapeutic potential for metabolic diseases, understanding the interplay between the types and dosing of WBV is critical for determining its utility and efficacy. Further studies are certainly needed to elucidate the full therapeutic potential of WBV in metabolic diseases.

Effects of device-performed and manual hip traction and vibration therapy in older adults with symptomatic hip osteoarthritis: A randomized single-blind controlled trial

BACKGROUND

Traction-and-vibration-therapy (TVT) relieves pain in participants with hip osteoarthritis. Hip TVT is usually performed manually by the physiotherapist.

OBJECTIVE

A medical device was developed to perform hip-TVT in order to investigate effects on hip disability, pain intensity, recovery of balance and functional mobility in older adults with hip osteoarthritis and also to reduce physiotherapists' workload and help standardize treatment of hip TVT.

METHODS

In a block-randomized 3-month controlled trial involving 28 older adult participants with symptomatic primary hip osteoarthritis (SPHOA), one group (n= 10) received device-performed TVT, one (n= 10) manual TVT, and one (n= 8) sham/placebo therapy. Hip disability (Harris Hip Score), pain intensity (visual-analog-scale), recovery of balance and gait (Functional Gait Assessment) and functional mobility (Timed-Up-and-Go-test) were assessed at baseline, after 3 weeks without intervention, and after 3-month intervention.

RESULTS

The Device TVT and Manual TVT groups exhibited superior outcomes compared to the Placebo group in terms of hip disability (p= 0.005 and p< 0.001, respectively), pain intensity (p= 0.002 and p< 0.001, respectively), and functional mobility (TUG) (p= 0.012 and p= 0.011, respectively). Furthermore, the recovery of balance and gait (FGA) showed a significant improvement in the Device TVT group when compared to the Placebo group (p= 0.043). The effect sizes ranged from 0.17 to 0.51, indicating moderate to large effects.

CONCLUSION

Device-performed-TVT is comparable to manual hip-TVT for reducing pain and improving mobility in older adults with SPHOA, and may be beneficial in terms of reducing physiotherapists' workload and better therapy standardization.

Alterations of Body Composition, Blood Morphology and Fibrinogen Concentration after Vibration Therapy in Older Adult Women: A Randomized Controlled Trial

Vibrotherapy is one of the methods of physical therapy. Vibration, like various forms of physical activity, affects metabolic processes and health. The aim of this study was to assess the influence of thirty vibration sessions on body composition, hematologic and rheological indexes of blood, and protein and fibrinogen concentration in elderly women's blood. The study included 69 women, aged 60-70 years (mean age 64.6 ± 2.9), who were randomly and parallel assigned into: the vibrotherapy group 1 (G1) that took part in vibrotherapy on the Knees module, the vibrotherapy group 2 (G2) that took part in vibrotherapy on the Metabolism module, and the control group (CG) without interventions. In all patients, the following assessments were performed twice-baseline and after thirty vibrotherapy sessions: an assessment of body composition, a complete blood count with a hematology analyzer and erythrocyte aggregation by a laser-optical rotational red cell analyzer; total plasma protein and fibrinogen concentrations were established, respectively, by biuret and spectrophotometric methods. Intergroup (between groups) and intragroup (within each group) changes were statistically evaluated. After applying thirty vibration sessions, a decrease in body composition parameters (BM, body mass G1, p < 0.05; G2, p < 0.001 and FFM, fat free mass G1, p < 0.05; G2, p < 0.05) was confirmed in both intervention groups and BMI, body mass index in G2 (p < 0.05). It was found that, in G2, changes in erythrocyte aggregation indexes (T ½, half time kinetics of aggregation, p < 0.05 and AI, aggregation index, p < 0.05) and decrease of fibrinogen concentration (p < 0.05) took place. A series of thirty vibration sessions did not cause significant alterations in blood morphological parameters; therefore, vibrotherapy did not disturb hematological balance. Vibration sessions had a positive effect on BM, BMI, AG and fibrinogen concentration in the studied women, indicating the usefulness of this form of activation in older adults. Due to a decrease in FFM observed in the study, vibrotherapy should be employed in conjunction with physical exercise and other forms of physical activity in the group of older adults.

Vibrational Force on Accelerating Orthodontic Tooth Movement: A Systematic Review and Meta-Analysis

This study aimed to systematically gather and analyze the current level of evidence for the effectiveness of the vibrational force in accelerating orthodontic tooth movement (OTM). This systematic review was conducted using three electronic databases: Scopus, PubMed, and Google Scholar until March 2022. The search was done through the following journals: European Journal of Orthodontics, American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, Progress in Orthodontics, and Seminars in Orthodontics. Human or animal studies that have evaluated the effect of vibrational force on the rate of OTM were selected. A meta-analysis was performed for the rate of canine movement per month. Database research, elimination of duplicate studies, data extraction, and risk of bias assessment were performed by authors independently and in duplication. A fixed and random-effect meta-analysis was performed to evaluate the effect of vibrational forces. A total of 19 studies (6 animal and 13 human studies) that met the inclusion criteria were included. Meta-analysis was performed based on four human clinical trials. Three out of four studies showed no significant difference in the rate of canine movement between vibrational force and control groups. The limitation of this study was the small sample size and significant heterogeneity among the studies. Although vibrational forces have been shown to accelerate OTM in experimental studies, the results are inconsistent in clinical studies. The inability to apply desired peak load to the targeted teeth may be the main factor in inconsistent clinical outcomes.

The myosin and RhoGAP MYO9B influences osteocyte dendrite growth and responses to mechanical stimuli

Introduction: Myosin IXB (MYO9B) is an unconventional myosin with RhoGAP activity and thus is a regulator of actin cytoskeletal organization. MYO9B was previously shown to be necessary for skeletal growth and health and to play a role in actin-based functions of both osteoblasts and osteoclasts. However, its role in responses to mechanical stimulation of bone cells has not yet been described. Therefore, experiments were undertaken to determine the role of MYO9B in bone cell responses to mechanical stress both in vitro and in vivo. Methods: MYO9B expression was knocked down in osteoblast and osteocyte cell lines using RNA interference and the resulting cells were subjected to mechanical stresses including cyclic tensile strain, fluid shear stress, and plating on different substrates (no substrate vs. monomeric or polymerized collagen type I). Osteocytic cells were also subjected to MYO9B regulation through Slit-Robo signaling. Further, wild-type or Myo9b -/- mice were subjected to a regimen of whole-body vibration (WBV) and changes in bone quality were assessed by micro-CT. Results: Unlike control cells, MYO9B-deficient osteoblastic cells subjected to uniaxial cyclic tensile strain were unable to orient their actin stress fibers perpendicular to the strain. Osteocytic cells in which MYO9B was knocked down exhibited elongated dendrites but were unable to respond normally to treatments that increase dendrite length such as fluid shear stress and Slit-Robo signaling. Osteocytic responses to mechanical stimuli were also found to be dependent on the polymerization state of collagen type I substrates. Wild-type mice responded to WBV with increased bone tissue mineral density values while Myo9b -/- mice responded with bone loss. Discussion: These results demonstrate that MYO9B plays a key role in mechanical stress-induced responses of bone cells in vitro and in vivo.

Effects of simulated microgravity and vibration on osteoblast and osteoclast activity in cultured zebrafish scales

Zebrafish cultured scales have been used effectively to study cellular and molecular responses of bone cells. In order to expose zebrafish scales to simulated microgravity (SMG) and/or vibration, we first determined via apoptosis staining whether cells of the scale survive in culture for two days and hence, we restricted our analyses to two-day durations. Next, we measured the effects of SMG and vibration on cell death, osteoclast tartrate-resistant acid phosphatase, and osteoblast alkaline phosphatase activity and on the number of Runx2a positive cells. We found that during the SMG treatment, osteoclast tartrate-resistant acid phosphatase activity increased on average, while the number of Runx2a positive cells decreased significantly. In contrast, SMG exposure caused a decrease in osteoblast activity. The vibration treatment showed an increase, on average, in the osteoblast alkaline phosphatase activity. This study demonstrates the effect of SMG and vibration on zebrafish scales and the effects of SMG on bone cells. We also show that zebrafish scales can be used to examine the effects of SMG on bone maintenance.

Cost-effectiveness analysis of sarcopenia management interventions in Iran

OBJECTIVES

Identification the optimal management intervention of sarcopenia is a concern of health systems. We aimed to analyze the cost-effectiveness of sarcopenia management strategies in Iran.

METHODS

We constructed a lifetime Markov model based on natural history. The strategies comparedincluded exercise training, nutritional supplements, whole body vibration (WBV), and various exercise interventions and nutritional supplement combinations. A total of 7 strategies was evaluated in addition to the non-intervention strategy. Parameter values were extracted from primary data and the literature, and the costs and Quality-adjusted life years (QALYs) were calculated for each strategy. Deterministic and probabilistic sensitivity analysis, including the expected value of perfect information (EVPI), was also performed to determine the robustness of the model. Analyses were performed using the 2020 version of TreeAge Pro software.

RESULTS

All seven strategies increased lifetime effectiveness (QALYs). The protein and Vitamin D₃ (P + D) strategy had the highest effectiveness values among all strategies. After removing the dominated strategies, the estimated ICER for the P + D compared to Vitamin D₃ alone (D) strategy was calculated as $131,229. Considering the cost-effectiveness threshold ($25,249), base-case results indicated that the D strategy was the most cost-effective strategy in this evaluation. Sensitivity analysis of model parameters also demonstrated the robustness of results. Also, EVPI was estimated at $273.

CONCLUSIONS

Study results, as the first economic evaluation of sarcopenia management interventions, showed that despite the higher effectiveness of D + P, the D strategy was the most cost-effective. Completing clinical evidence of various intervention options can lead to more accurate results in the future.

Activation function 2 (AF2) domain of estrogen receptor-α regulates mechanotransduction during bone fracture healing in estrogen-competent mice

External mechanostimulation applied by whole-body low-magnitude high-frequency vibration (LMHFV) was demonstrated to cause no or negative effects on fracture healing in estrogen-competent rodents, while in ovariectomized (OVX), estrogen-deficient rodents bone formation after fracture was improved. Using mice with an osteoblast-specific deletion of the estrogen receptor α (ERα), we demonstrated that ERα signaling in osteoblasts is required for both the anabolic and catabolic effects of LMHFV during bone fracture healing in OVX and non-OVX mice, respectively. Because the vibration effects mediated by ERα were strictly dependent on the estrogen status, we hypothesized different roles of ligand-dependent and -independent ERα signaling. To investigate this assumption in the present study, we used mice with a deletion of the C-terminal activation function (AF) domain-2 of the ERα receptor, which mediated ligand-dependent ERα signaling (ERαAF-2⁰). OVX and non-OVX ERαAF-2⁰ animals were subjected to femur osteotomy followed by vibration treatment. We revealed that estrogen-competent mice lacking the AF-2 domain were protected from LMHFV-induced impaired bone regeneration, while the anabolic effects of vibration in OVX mice were not affected by the AF-2 knockout. RNA sequencing further showed that genes involved in Hippo/Yap1-Taz and Wnt signaling were significantly downregulated upon LMHFV in the presence of estrogen in vitro. In conclusion, we demonstrated that the AF-2 domain is crucial for the negative effects of vibration during bone fracture healing in estrogen-competent mice suggesting that the osteoanabolic effects of vibration are rather mediated by ligand-independent ERα signaling.

Is it time for doctors to Rx vibrators? A systematic review of pelvic floor outcomes

Introduction

Vibrators and similar devices are an underutilized treatment modality in pelvic and sexual medicine, likely because of the limited knowledge on the health benefits of their use.

Objectives

The aim of this study was to review available data regarding the effect of vibrator use on sexual function, pelvic floor function, and chronic unexplained vulvar pain.

Methods

We performed a systematic literature review of PubMed, Embase, and MEDLINE from inception to March 2021 per the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses). The search was based on the following keywords: sex toy woman, pelvic vibrator, sexual stimulation vibrator, vaginal vibrator, vibrator pelvic floor, vibrator incontinence, and vulvar pain vibrator. An overall 586 articles were identified. Studies that met inclusion criteria were reviewed: original research, sample of women, vibrator use, and application to the pelvic/genital area. Exclusion criteria included case reports, unrelated content, vibrator not applied to the pelvic/genital area, male participants, or conditions of interest not addressed. A total of 17 original studies met the criteria and were reviewed in depth.

Results

After review of the literature and identification of articles appropriate for the study, there were 8 studies surrounding sexual function, 8 on pelvic floor function (muscle strength/urinary incontinence), and 1 on vulvar pain. Among the identified studies, vibrators were considered an accepted modality to enhance a woman’s sexual experience, improve pelvic floor muscle function, and facilitate treatment of vulvar pain.

Conclusions

Vibrators are not well studied, and given the promising benefits demonstrated in the articles identified, future research efforts should be directed toward investigating their utility. Considering the potential pelvic health benefits of vibrators, their recommendation to women could be included in our pelvic floor disorder treatment armamentarium.

The skeleton in a physical world

All organisms exist within a physical space and respond to physical forces as part of daily life. In higher organisms, the skeleton is critical for locomotion in the physical environment, providing a carapace upon which the animal can move to accomplish functions necessary for living. As such, the skeleton has responded evolutionarily, and does in real-time, to physical stresses placed on it to ensure that its structure supports its function in the sea, in the air, and on dry land. In this article, we consider how those cells responsible for remodeling skeletal structure respond to mechanical force including load magnitude, frequency, and cyclicity, and how force rearranges cellular structure in turn. The effects of these forces to balance the mesenchymal stem cell supply of bone-forming osteoblasts and energy storing adipocytes are addressed. That this phenotypic switching is achieved at the level of both gene transactivation and alteration of structural epigenetic controls of gene expression is considered. Finally, as clinicians, we consider this information as it applies to a prescriptive for intelligent exercise.

Effect of Whole-Body Vibration on Serum Levels of Brain Derived Neurotrophic Factor and Cortisol in Young, Healthy Women

Vibration exercises on a platform (whole-body vibration, WBV), widely used in rehabilitation, sports medicine, and fitness, is an alternative to strength effort. The presented study assessed the effect of a 12-week cycle of vibration training on the serum concentrations of brain-derived neurotrophic factor (BDNF) and cortisol in young women (trial ID: ACTRN 12621000114842). Volunteers were assigned to three groups: performing exercises on a vibrating platform (n = 17), performing identical exercises without a platform (n = 12), and passive control group (n = 17). The concentration of BDNF and cortisol was assessed four times: before the first training session, 5 min after it, also before, and 5 min after the last training session. There were no statistically significant changes in the groups or among groups for both substances. WBV in the presented form did not increase the secretion of BDNF and is not a stressful stimulus.

A Proposal for a Novel Formulation Based on the Hyperbolic Cattaneo’s Equation to Describe the Mechano-Transduction Process Occurring in Bone Remodeling

In this paper, we propose a model for the mechanical stimulus involved in the process of bone remodeling together with its evolution over time. Accumulated evidence suggests that bone remodeling could be interpreted as a feedback control process in which the mechanical state of the bone tissue is monitored, then appropriate signals are derived from the daily mechanical usage of the bone, these signals are transmitted into the surrounding region, and then they are detected by other agents whose purpose is to adapt the bone mass to the mechanical requirements of the environment. Therefore, we employ the diffusion equation for mass transport which is improved with Cattaneo’s correction to model the stimulus. This last improvement considers the effects of relaxation and non-locality, which we believe play essential roles in signaling messengers transport phenomena and are essential to match the evidence that suggests time-dependent excitations provide a more significant response at specific frequencies. To illustrate this particular behavior, numerical simulations have been performed in a 2D framework. The results fit the central aspect addressed, related to the dependency of the time of the adaptive process of bone, suggesting that our model is promising and deserves further investigation, both theoretical and experimental.

The Mechanosensory Role of Osteocytes and Implications for Bone Health and Disease States

Bone homeostasis is a dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. This process is primarily controlled by the most abundant and mechanosensitive bone cells, osteocytes, that reside individually, within chambers of porous hydroxyapatite bone matrix. Recent studies have unveiled additional functional roles for osteocytes in directly contributing to local matrix regulation as well as systemic roles through endocrine functions by communicating with distant organs such as the kidney. Osteocyte function is governed largely by both biochemical signaling and the mechanical stimuli exerted on bone. Mechanical stimulation is required to maintain bone health whilst aging and reduced level of loading are known to result in bone loss. To date, both in vivo and in vitro approaches have been established to answer important questions such as the effect of mechanical stimuli, the mechanosensors involved, and the mechanosensitive signaling pathways in osteocytes. However, our understanding of osteocyte mechanotransduction has been limited due to the technical challenges of working with these cells since they are individually embedded within the hard hydroxyapatite bone matrix. This review highlights the current knowledge of the osteocyte functional role in maintaining bone health and the key regulatory pathways of these mechanosensitive cells. Finally, we elaborate on the current therapeutic opportunities offered by existing treatments and the potential for targeting osteocyte-directed signaling.

The effect of low-intensity whole-body vibration with or without high-intensity resistance and impact training on risk factors for proximal femur fragility fracture in postmenopausal women with low bone mass: study protocol for the VIBMOR randomized controlled trial

BACKGROUND

The prevailing medical opinion is that medication is the primary (some might argue, only) effective intervention for osteoporosis. It is nevertheless recognized that osteoporosis medications are not universally effective, tolerated, or acceptable to patients. Mechanical loading, such as vibration and exercise, can also be osteogenic but the degree, relative efficacy, and combined effect is unknown. The purpose of the VIBMOR trial is to determine the efficacy of low-intensity whole-body vibration (LIV), bone-targeted, high-intensity resistance and impact training (HiRIT), or the combination of LIV and HiRIT on risk factors for hip fracture in postmenopausal women with osteopenia and osteoporosis.

METHODS

Postmenopausal women with low areal bone mineral density (aBMD) at the proximal femur and/or lumbar spine, with or without a history of fragility fracture, and either on or off osteoporosis medications will be recruited. Eligible participants will be randomly allocated to one of four trial arms for 9 months: LIV, HiRIT, LIV + HiRIT, or control (low-intensity, home-based exercise). Allocation will be block-randomized, stratified by use of osteoporosis medications. Testing will be performed at three time points: baseline (T0), post-intervention (T1; 9 months), and 1 year thereafter (T2; 21 months) to examine detraining effects. The primary outcome measure will be total hip aBMD determined by dual-energy X-ray absorptiometry (DXA). Secondary outcomes will include aBMD at other regions, anthropometrics, and other indices of bone strength, body composition, physical function, kyphosis, muscle strength and power, balance, falls, and intervention compliance. Exploratory outcomes include bone turnover markers, pelvic floor health, quality of life, physical activity enjoyment, adverse events, and fracture. An economic evaluation will also be conducted.

DISCUSSION

No previous studies have compared the effect of LIV alone or in combination with bone-targeted HiRIT (with or without osteoporosis medications) on risk factors for hip fracture in postmenopausal women with low bone mass. Should either, both, or combined mechanical interventions be safe and efficacious, alternative therapeutic avenues will be available to individuals at elevated risk of fragility fracture who are unresponsive to or unwilling or unable to take osteoporosis medications.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (www. anzctr.org.au ) (Trial number ANZCTR12615000848505, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id = 368962 ); date of registration 14/08/2015 (prospectively registered). Universal Trial Number: U1111-1172-3652.

Estrogen Receptor α Signaling in Osteoblasts is Required for Mechanotransduction in Bone Fracture Healing

Biomechanical stimulation by whole-body low-magnitude high-frequency vibration (LMHFV) has demonstrated to provoke anabolic effects on bone metabolism in both non-osteoporotic and osteoporotic animals and humans. However, preclinical studies reported that vibration improved fracture healing and bone formation in osteoporotic, ovariectomized (OVX) mice representing an estrogen-deficient hormonal status, but impaired bone regeneration in skeletally healthy non-OVX mice. These effects were abolished in general estrogen receptor α (ERα)-knockout (KO) mice. However, it remains to be elucidated which cell types in the fracture callus are targeted by LMHFV during bone healing. To answer this question, we generated osteoblast lineage-specific ERα-KO mice that were subjected to ovariectomy, femur osteotomy and subsequent vibration. We found that the ERα specifically on osteoblastic lineage cells facilitated the vibration-induced effects on fracture healing, because in osteoblast lineage-specific ERα-KO (ERαfl/fl; Runx2Cre) mice the negative effects in non-OVX mice were abolished, whereas the positive effects of vibration in OVX mice were reversed. To gain greater mechanistic insights, the influence of vibration on murine and human osteogenic cells was investigated in vitro by whole genome array analysis and qPCR. The results suggested that particularly canonical WNT and Cox2/PGE2 signaling is involved in the mechanotransduction of LMHFV under estrogen-deficient conditions. In conclusion, our study demonstrates a critical role of the osteoblast lineage-specific ERα in LMHFV-induced effects on fracture healing and provides further insights into the molecular mechanism behind these effects.

Immediate Effects of Whole-Body Vibration Associated with Squatting Exercises on Hemodynamic Parameters in Sarcopenic Older People: A Randomized Controlled Trial

Whole-body vibration (WBV) exercises have recently been introduced as a nonpharmacological therapeutic strategy for sarcopenic older people. The present study aimed to evaluate the effect of WBV exercise on hemodynamic parameters in sarcopenic older people. Forty older people, divided into groups of nonsarcopenic (NSG = 20) and sarcopenic (SG = 20), participated in the study and were cross randomized into two interventions of eight sets of 40 s each, these being squatting with WBV and squatting without WBV. Heart rate (HR), peak heart rate (peak HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), double product (DP), mean arterial pressure (MAP), and subjective perception of effort (SPE), were assessed at baseline, during, and after a single WBV session. The HR, peak HR, and DP variables were similar at baseline between groups. WBV exercise increased all the hemodynamic parameters both during and immediately after the intervention, in both groups (SG and NSG). The MAP values were similar at baseline between groups; however, in the NSG there was a significant increase during and immediately after the squatting with WBV intervention (p < 0.05). The HR behavior, in both groups, showed that there was an increase in HR after the first set of exercises with vibration and this increase was maintained until the final set. The absence of adverse effects of WBV exercise on the cardiovascular system and fatigue suggests this exercise modality is adequate and safe for sarcopenic older people.

Mechanobiology-based physical therapy and rehabilitation after orthobiologic interventions: a narrative review

PURPOSE

This review aims to summarize the evidence for the role of mechanotherapies and rehabilitation in supporting the synergy between regeneration and repair after an orthobiologic intervention.

METHODS

A selective literature search was performed using Web of Science, OVID, and PubMed to review research articles that discuss the effects of combining mechanotherapy with various forms of regenerative medicine.

RESULTS

Various mechanotherapies can encourage the healing process for patients at different stages. Taping, bracing, cold water immersion, and extracorporeal shockwave therapy can be used throughout the duration of acute inflammatory response. The regulation of angiogenesis can be sustained with blood flow restriction and resistance training, whereas heat therapy and tissue loading during exercise are recommended in the remodeling phase.

CONCLUSION

Combining mechanotherapy with various forms of regenerative medicine has shown promise for improving treatment outcomes. However, further studies that reveal a greater volume of evidence are needed to support clinical decisions.

The Osteogenic Differentiation of Human Dental Pulp Stem Cells through G0/G1 Arrest and the p-ERK/Runx-2 Pathway by Sonic Vibration

Mechanical/physical stimulations modulate tissue metabolism, and this process involves multiple cellular mechanisms, including the secretion of growth factors and the activation of mechano-physically sensitive kinases. Cells and tissue can be modulated through specific vibration-induced changes in cell activity, which depend on the vibration frequency and occur via differential gene expression. However, there are few reports about the effects of medium-magnitude (1.12 g) sonic vibration on the osteogenic differentiation of human dental pulp stem cells (HDPSCs). In this study, we investigated whether medium-magnitude (1.12 g) sonic vibration with a frequency of 30, 45, or 100 Hz could affect the osteogenic differentiation of HDPSCs. Their cell morphology changed to a cuboidal shape at 45 Hz and 100 Hz, but the cells in the other groups were elongated. FACS analysis showed decreased CD 73, CD 90, and CD 105 expression at 45 Hz and 100 Hz. Additionally, the proportions of cells in the G0/G1 phase in the control, 30 Hz, 45 Hz, and 100 Hz groups after vibration were 60.7%, 65.9%, 68.3%, and 66.7%, respectively. The mRNA levels of osteogenic-specific markers, including osteonectin, osteocalcin, BMP-2, ALP, and Runx-2, increased at 45 and 100 Hz, and the ALP and calcium content was elevated in the vibration groups compared with those in the control. Additionally, the western blotting results showed that p-ERK, BSP, osteoprotegerin, and osteonectin proteins were upregulated at 45 Hz compared with the other groups. The vibration groups showed higher ALP and calcium content than the control. Vibration, especially at 100 Hz, increased the number of calcified nodes relative to the control group, as evidenced by von Kossa staining. Immunohistochemical staining demonstrated that type I and III collagen, osteonectin, and osteopontin were upregulated at 45 Hz and 100 Hz. These results suggest that medium magnitude vibration at 45 Hz induces the G0/G1 arrest of HDPSCs through the p-ERK/Runx-2 pathway and can serve as a potent stimulator of differentiation and extracellular matrix production.

Suppression of cancer-associated bone loss through dynamic mechanical loading

Patients afflicted with or being treated for cancer constitute a distinct and alarming subpopulation who exhibit elevated fracture risk and heightened susceptibility to developing secondary osteoporosis. Cancer cells uncouple the regulatory processes central for the adequate regulation of musculoskeletal tissue. Systemically taxing treatments to target tumors or disrupt the molecular elements driving tumor growth place considerable strain on recovery efforts. Skeletal tissue is inherently sensitive to mechanical forces, therefore attention to exercise and mechanical loading as non-pharmacological means to preserve bone during treatment and in post-treatment rehabilitative efforts have been topics of recent focus. This review discusses the dysregulation that cancers and the ensuing metabolic dysfunction that confer adverse effects on musculoskeletal tissues. Additionally, we describe foundational mechanotransduction pathways and the mechanisms by which they influence both musculoskeletal and cancerous cells. Functional and biological implications of mechanical loading at the tissue and cellular levels will be discussed, highlighting the current understanding in the field. Herein, in vitro, translational, and clinical data are summarized to consider the positive impact of exercise and low magnitude mechanical loading on tumor-bearing skeletal tissue.

Mechanical suppression of breast cancer cell invasion and paracrine signaling to osteoclasts requires nucleo-cytoskeletal connectivity

Exercise benefits the musculoskeletal system and reduces the effects of cancer. The effects of exercise are multifactorial, where metabolic changes and tissue adaptation influence outcomes. Mechanical signals, a principal component of exercise, are anabolic to the musculoskeletal system and restrict cancer progression. We examined the mechanisms through which cancer cells sense and respond to low-magnitude mechanical signals introduced in the form of vibration. Low-magnitude, high-frequency vibration was applied to human breast cancer cells in the form of low-intensity vibration (LIV). LIV decreased matrix invasion and impaired secretion of osteolytic factors PTHLH, IL-11, and RANKL. Furthermore, paracrine signals from mechanically stimulated cancer cells, reduced osteoclast differentiation and resorptive capacity. Disconnecting the nucleus by knockdown of SUN1 and SUN2 impaired LIV-mediated suppression of invasion and osteolytic factor secretion. LIV increased cell stiffness; an effect dependent on the LINC complex. These data show that mechanical vibration reduces the metastatic potential of human breast cancer cells, where the nucleus serves as a mechanosensory apparatus to alter cell structure and intercellular signaling.

Effects of vibration therapy on muscle mass, muscle strength and physical function in older adults with sarcopenia: a systematic review and meta-analysis

Background

Sarcopenia, a progressive loss of muscle mass and function with advancing age, is a prevalent condition among older adults. As most older people are too frail to do intensive exercise and vibration therapy has low risk and ease of participation, it may be more readily accepted by elderly individuals. However, it remains unclear whether vibration therapy would be effective among older adults with sarcopenia. This systematic review and meta-analysis examined the effect of vibration therapy including local vibration therapy and whole-body vibration therapy, for enhancing muscle mass, muscle strength and physical function in older people with sarcopenia.

Methods

A systematic literature search was conducted in March 2019 in the following 5 electronic databases: PubMed, CINAHL, Embase, PEDro, and the Cochrane Central Register of Controlled Trials, with no restriction of language or the year of publication. Randomized controlled trials and quasi-experimental studies examining effects of vibration therapy on muscle mass, muscle strength or physical function in older adults with sarcopenia were included in this systematic review. Two reviewers independently assessed the methodological quality of the selected studies.

Results

Of the 1972 identified studies, seven publications from six studies involving 223 participants were included in this systematic review. Five of them conducted whole-body vibration therapy, while two conducted local vibration therapy. A meta-analysis of randomized controlled studies indicated that muscle strength significantly increased after whole-body vibration therapy (SMD 0.69, 95% CI 0.28 to 1.11, I² = 0%, P = 0.001) and local vibration therapy (SMD 3.78, 95% CI 2.29 to 5.28, P < 0.001). Physical performance measured by the sit-to-stand test and the timed-up-and-go test were significantly improved after the intervention (SMD -0.79, 95% CI − 1.21 to − 0.37, I² = 0%, P < 0.001) and SMD -0.83, 95% CI − 1.56 to − 0.11, I² = 64%, P = 0.02, respectively).

Conclusion

Vibration therapy could be a prospective strategy for improving muscle strength and physical performance in older adults with sarcopenia. However, due to the limited number of the included studies, caution is needed when interpreting these results. More well-designed, large sample size studies should be conducted to further explore and validate the benefits of vibration therapy for this population.

Histological and Radiological Evaluation of Low-Intensity Pulsed Ultrasound Versus Whole Body Vibration on Healing of Mandibular Bone Defects in Rats

Background and Objectives: Mechanical stimulation can improve the structural properties of the fracture site and induce the differentiation of different cell types for bone regeneration. This study aimed to compare the effect of low-intensity pulsed ultrasound stimulation (LIPUS) versus whole body vibration (WBV) on healing of mandibular bone defects. Materials and Methods: A mandibular defect was created in 66 rats. The rats were randomly divided into two groups of rats. Each group was subdivided randomly by three groups (n = 11) as follows: (I) control group, (II) treatment with LIPUS, and (III) treatment with WBV. The radiographic changes in bone density, the ratio of lamellar bone to the entire bone volume, the ratio of the newly formed bone to the connective tissue and inflammation grade were evaluated after 1 and 2 months. Results: LIPUS significantly increased the radiographic bone density change compared to the control group at the first and second month postoperatively (p < 0.01). WBV only significantly increased the bone density compared to the control group at the second month after the surgery (p < 0.01). Conclusions: Application of LIPUS and WBV may enhance the regeneration of mandibular bone defects in rats. Although LIPUS and WBV are effective in mandibular bone healing, the effects of LIPUS are faster and greater than WBV.

Recent Advances in Mechanically Loaded Human Mesenchymal Stem Cells for Bone Tissue Engineering

Large bone defects are a major health concern worldwide. The conventional bone repair techniques (e.g., bone-grafting and Masquelet techniques) have numerous drawbacks, which negatively impact their therapeutic outcomes. Therefore, there is a demand to develop an alternative bone repair approach that can address the existing drawbacks. Bone tissue engineering involving the utilization of human mesenchymal stem cells (hMSCs) has recently emerged as a key strategy for the regeneration of damaged bone tissues. However, the use of tissue-engineered bone graft for the clinical treatment of bone defects remains challenging. While the role of mechanical loading in creating a bone graft has been well explored, the effects of mechanical loading factors (e.g., loading types and regime) on clinical outcomes are poorly understood. This review summarizes the effects of mechanical loading on hMSCs for bone tissue engineering applications. First, we discuss the key assays for assessing the quality of tissue-engineered bone grafts, including specific staining, as well as gene and protein expression of osteogenic markers. Recent studies of the impact of mechanical loading on hMSCs, including compression, perfusion, vibration and stretching, along with the potential mechanotransduction signalling pathways, are subsequently reviewed. Lastly, we discuss the challenges and prospects of bone tissue engineering applications.

Low magnitude high frequency vibrations expedite the osteogenesis of bone marrow stem cells on paper based 3D scaffolds

Anabolic effects of low magnitude high frequency (LMHF) vibrations on bone tissue were consistently shown in the literature in vivo, however in vitro efforts to elucidate underlying mechanisms are generally limited to 2D cell culture studies. Three dimensional cell culture platforms better mimic the natural microenvironment and biological processes usually differ in 3D compared to 2D culture. In this study, we used laboratory grade filter paper as a scaffold material for studying the effects of LHMF vibrations on osteogenesis of bone marrow mesenchymal stem cells in a 3D system. LMHF vibrations were applied 15 min/day at 0.1 g acceleration and 90 Hz frequency for 21 days to residing cells under quiescent and osteogenic conditions. mRNA expression analysis was performed for alkaline phosphatase (ALP) and osteocalcin (OCN) genes, Alizarin red S staining was performed for mineral nodule formation and infrared spectroscopy was performed for determination of extracellular matrix composition. The highest osteocalcin expression, mineral nodule formation and the phosphate bands arising from the inorganic phase was observed for the cells incubated in osteogenic induction medium with vibration. Our results showed that filter paper can be used as a model scaffold system for studying the effects of mechanical loads on cells, and LMHF vibrations induced the osteogenic differentiation of stem cells.

Wireless Power Transfer Techniques for Implantable Medical Devices: A Review

Wireless power transfer (WPT) systems have become increasingly suitable solutions for the electrical powering of advanced multifunctional micro-electronic devices such as those found in current biomedical implants. The design and implementation of high power transfer efficiency WPT systems are, however, challenging. The size of the WPT system, the separation distance between the outside environment and location of the implanted medical device inside the body, the operating frequency and tissue safety due to power dissipation are key parameters to consider in the design of WPT systems. This article provides a systematic review of the wide range of WPT systems that have been investigated over the last two decades to improve overall system performance. The various strategies implemented to transfer wireless power in implantable medical devices (IMDs) were reviewed, which includes capacitive coupling, inductive coupling, magnetic resonance coupling and, more recently, acoustic and optical powering methods. The strengths and limitations of all these techniques are benchmarked against each other and particular emphasis is placed on comparing the implanted receiver size, the WPT distance, power transfer efficiency and tissue safety presented by the resulting systems. Necessary improvements and trends of each WPT techniques are also indicated per specific IMD.

The Effects of Vibration and Pressure Treatments in the Early Postoperative Period of Rhinoplasty

BACKGROUND

The early postoperative period can be distressing for the patients undergoing rhinoplasty since edema and ecchymosis are common complications.

OBJECTIVES

To analyze the effects of the vibration and pressure treatments in the early postoperative period of rhinoplasty.

METHODS

Sixty patients, who had undergone rhinoplasty, were randomized into 3 groups: group 1 (control group, n = 20) received classic nasal casting, group 2 (n = 20) received nasal cast with an elastic bandage to hold it on the face, and group 3 (n = 20) received vibration treatment in addition to that in group 2 following the rhinoplasty. They were evaluated preoperatively and postoperatively at 3 and 7 days in a prospective study. The postoperative edema and ecchymosis were scored by 2 independent surgeons. The postoperative pain was measured using the visual analog scale, and the necessity of anti-inflammatory medication (and the dose needed) and the cast comfort was questioned. The sebaceous activity of the nose skin was examined. A preoperative and postoperative seventh day sonographic study was performed to evaluate the tissue edema objectively.

RESULTS

The pressure treatment decreased the edema and ecchymosis significantly compared with the control group. The vibration treatment minimized edema, ecchymosis, sebaceous activity of the nose skin, pain score, and the need for anti-inflammatory medication, and increased the cast comfort significantly compared with the other groups (P < 0.0001).

CONCLUSIONS

Rapid regression of edema and ecchymosis may be achieved using the vibrating nasal cast technique that may minimize patient discomfort, pain, and sebaceous activity following rhinoplasty.

LEVEL OF EVIDENCE: 1

Vibration of osteoblastic cells using a novel motion-control platform does not acutely alter cytosolic calcium, but desensitizes subsequent responses to extracellular ATP

Low-magnitude high-frequency mechanical vibration induces biological responses in many tissues. Like many cell types, osteoblasts respond rapidly to certain forms of mechanostimulation, such as fluid shear, with transient elevation in the concentration of cytosolic free calcium ([Ca²⁺ ]_i ). However, it is not known whether vibration of osteoblastic cells also induces acute elevation in [Ca²⁺ ]_i . To address this question, we built a platform for vibrating live cells that is compatible with microscopy and microspectrofluorometry, enabling us to observe immediate responses of cells to low-magnitude high-frequency vibrations. The horizontal vibration system was mounted on an inverted microscope, and its mechanical performance was evaluated using optical tracking and accelerometry. The platform was driven by a sinusoidal signal at 20-500 Hz, producing peak accelerations from 0.1 to 1 g. Accelerometer-derived displacements matched those observed optically within 10%. We then used this system to investigate the effect of acceleration on [Ca²⁺ ]_i in rodent osteoblastic cells. Cells were loaded with fura-2, and [Ca²⁺ ]_i was monitored using microspectrofluorometry and fluorescence ratio imaging. No acute changes in [Ca²⁺ ]_i or cell morphology were detected in response to vibration over the range of frequencies and accelerations studied. However, vibration did attenuate Ca²⁺ transients generated subsequently by extracellular ATP, which activates P2 purinoceptors and has been implicated in mechanical signaling in bone. In summary, we developed and validated a motion-control system capable of precisely delivering vibrations to live cells during real-time microscopy. Vibration did not elicit acute elevation of [Ca²⁺ ]_i , but did desensitize responses to later stimulation with ATP.

Effectiveness and importance of powered tooth brushes in tooth movement

Introduction:

Effectiveness of vibratory stimulus from a commonly available battery-powered tooth brush in accelerating orthodontic tooth movement was tested by a randomized controlled split-mouth study.

Materials and Methods:

Twenty-three subjects with bimaxillary protrusion, requiring extraction of all first premolars and requiring maximum anchorage, were chosen. After initial leveling and aligning, miniscrews were placed between the first molar and the second premolar in the maxillary right and left quadrants and loaded with 150-g nickel–titanium closed-coil springs for individual canine retraction. Additional 5 min of vibratory stimulus thrice daily was applied on the experimental side. The mean treatment duration was 3 months.

Results:

There was no significant difference of means of the canine distal movement between the experimental and the control sides (P = 0.70).

Conclusion:

Application of vibratory stimulus with powered tooth brush during canine retraction was not seen to have an acceleratory effect on orthodontic tooth movement.

Assessment of acute bone loading in humans using [18F]NaF PET/MRI

PURPOSE

The acute effect of loading on bone tissue and physiology can offer important information with regard to joint function in diseases such as osteoarthritis. Imaging studies using [¹⁸F]-sodium fluoride ([¹⁸F]NaF) have found changes in tracer kinetics in animals after subjecting bones to strain, indicating an acute physiological response. The aim of this study is to measure acute changes in NaF uptake in human bone due to exercise-induced loading.

METHODS

Twelve healthy subjects underwent two consecutive 50-min [¹⁸F]NaF PET/MRI examinations of the knees, one baseline followed by one post-exercise scan. Quantification of tracer kinetics was performed using an image-derived input function from the popliteal artery. For both scans, kinetic parameters of K_i^NLR, K₁, k₂, k₃, and blood volume were mapped parametrically using nonlinear regression with the Hawkins model. The kinetic parameters along with mean SUV and SUV_max were compared between the pre- and post-exercise examinations. Differences in response to exercise were analysed between bone tissue types (subchondral, cortical, and trabecular bone) and between regional subsections of knee subchondral bone.

RESULTS

Exercise induced a significant (p < <0.001) increase in [¹⁸F]NaF uptake in all bone tissues in both knees, with mean SUV increases ranging from 47% in trabecular bone tissue to 131% in subchondral bone tissue. Kinetic parameters involving vascularization (K₁ and blood volume) increased, whereas the NaF extraction fraction [k₃/(k₂ + k₃)] was reduced.

CONCLUSIONS

Bone loading induces an acute response in bone physiology as quantified by [¹⁸F]NaF PET kinetics. Dynamic imaging after bone loading using [¹⁸F]NaF PET is a promising diagnostic tool in bone physiology and imaging of biomechanics.

An experimental evaluation of fracture movement in two alternative tibial fracture fixation models using a vibrating platform

Several studies have investigated the effect of low-magnitude-high-frequency vibration on the outcome of fracture healing in animal models. The aim of this study was to quantify and compare the micromovement at the fracture gap in a tibial fracture fixed with an external fixator in both a surrogate model of a tibial fracture and a cadaver human leg under static loading, both subjected to vibration. The constructs were loaded under static axial loads of 50, 100, 150 and 200 N and then subjected to vibration at each load using a commercial vibration platform, using a DVRT sensor to quantify static and dynamic fracture movement. The overall stiffness of the cadaver leg was significantly higher than the surrogate model under static loading. This resulted in a significantly higher fracture movement in the surrogate model. Under vibration, the fracture movements induced at the fracture gap in the surrogate model and the cadaver leg were 0.024 ± 0.009 mm and 0.016 ± 0.002 mm, respectively, at 200 N loading. Soft tissues can alter the overall stiffness and fracture movement recorded in biomechanical studies investigating the effect of various devices or therapies. While the relative comparison between the devices or therapies may remain valid, absolute magnitude of recordings measured externally must be interpreted with caution.

Hand-arm vibration syndrome

Use of vibrating tools often leads to development of hand-arm vibration syndrome. It manifests with vascular symptoms, neurologic (carpal tunnel syndrome) and musculoskeletal symptoms (impaired grip strength, osteoarthritis, bone necrosis). Kienböck's disease is osteonecrosis of the lunate. A 61-year-old construction worker was referred to a rheumatologist because of suspected arthritis. On examination tenderness and swelling of the dorsal aspect of the right wrist were recorded without features of inflammation. The patient reported paresthesia in the right hand when working with a pneumatic drill. He reported no morning stiffness or Raynaud's phenomenon. He had undergone surgery because of right carpal tunnel syndrome two years earlier. Rheumatoid factor was negative, CRP 0.2 mg/l, uric acid 4.7 mg/dl. In magnetic resonance avascular necrosis of the lunate was diagnosed and scaphoid fracture. Kienböck's disease was diagnosed. Non-steroidal anti-inflammatory drugs were used. The patient did not give consent for surgery.

Bone changes after short-term whole body vibration are confined to cancellous bone

OBJECTIVE

This study assessed femur properties in 80 adult female rats exposed to a range of whole body vibration amplitudes at 45 Hz over five weeks. Our hypothesis was that an optimal amplitude for whole body vibration would be apparent and would result in increased bone strength.

METHODS

Animals were treated in five amplitude groups (0 g, 0.15 g, 0.3 g, 0.6 g, and 1.2 g peak), for 15 minutes per day, five days per week, for five weeks. Femur strength was assessed via: (1) three-point bending of the shaft, (2) cantilever bending of the neck, and (3) indentation of distal cancellous bone. Femoral bone mineral density, plasma prostaglandin E2 (PGE₂) concentrations, cartilage thickness, and histopathologic properties were measured.

RESULTS

Vibration doubled (P=0.039) cancellous bone stiffness in the 0.6 g and 1.2 g groups and induced a 74% increase in PGE2 concentrations (P=0.007). However, femoral densitometry and strength of the neck and shaft were unchanged and the cancellous bone indentation strength did not differ statistically (P=0.084). Cartilage thickness of vibrated groups at the medial condyle did not increase significantly (P=0.142) and the histopathologic grade did not change. There was no definitive optimal vibration amplitude.

CONCLUSION

The benefits of vibration therapy over five weeks were confined to cancellous bone.

Effect of cyclical forces on orthodontic tooth movement, from animals to humans

Vibration as a non-invasive method is currently available for clinical use with the potential to accelerate the rate of tooth movement in orthodontics. The aim of this review was to evaluate the basic science and clinical literature on the effects of vibration on the axial and appendicular skeleton including the craniofacial bone. Vibration as a dynamic load consisting of high oscillatory forces of low magnitude has shown osteogenic and anti-catabolic effects on bone. These effects have been observed in the craniofacial skeleton including the alveolar bone as increases in sutural width and alveolar bone formation. Animal studies have shown conflicting results on vibration when superposed to orthodontic tooth movement. The effects range from increasing to decreasing the rate of tooth movement. Clinical studies in accelerating the rate of tooth movement have similar findings observed in animal studies. High-frequency oscillatory forces of low magnitude are able to affect bone formation and remodelling. These effects of vibration are primarily anabolic and anti-catabolic in bone, including the craniofacial skeleton and alveolar bone. The effect of vibration on accelerating the rate of orthodontic tooth movement is contradictory. Higher levels of evidence studies have not been able to show an acceleratory effect.

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).

Bone Remodeling under Vibration: A Computational Model of Bone Remodeling Incorporating the Modal Behavior of Bone

Developing precise computational models of bone remodeling can lead to more successful types of orthopedic treatments and deeper understanding of the phenomenon. Empirical evidence has shown that bone adaptation to mechanical loading is frequency dependent and the modal behavior of bone under vibration can play a significant role in remodeling process, particularly in the resonance region. The objective of this study is to develop a bone remodeling algorithm that takes into account the effects of bone vibrational behavior. An extended/modified model is presented based on conventional FE remodeling models. Frequency domain analysis is used to introduce appropriate correction coefficients to incorporate the effect of bone's frequency response into the model. The method is implemented on a bovine bone with known modal/vibration characteristics. The rate and locations of new bone formation depend on the loading frequency and are consistently correlated with the bone modal behavior. The proposed method can successfully integrate the bone vibration conditions and characteristics with the remodeling process. The results obtained support experimental observations in the literature.

Vibration in mice: A review of comparative effects and use in translational research

Sound pressure waves surround individuals in everyday life and are perceived by animals and humans primarily through sound or vibration. When sound pressure waves traverse through a solid medium, vibration will result. Vibration has long been considered an unwanted variable in animal research and may confound scientific endeavors using animals. Understanding the characteristics of vibration is required to determine whether effects in animals are likely to be therapeutic or result in adverse biological effects. The eighth edition of the "Guide for the Care and Use of Laboratory Animals" highlights the importance of considering vibration and its effects on animals in the research setting, but knowledge of the level of vibration for eliciting these effects was unknown. The literature provides information regarding therapeutic use of vibration in humans, but the range of conditions to be of therapeutic benefit is varied and without clarity. Understanding the characteristics of vibration (eg, frequency and magnitude) necessary to cause various effects will ultimately assist in the evaluation of this environmental factor and its role on a number of potential therapeutic regimens for use in humans. This paper will review the principles of vibration, sources within a research setting, comparative physiological effects in various species, and the relative potential use of vibration in the mouse as a translational research model.

Effect of localised vibration on muscle strength in healthy adults: a systematic review

OBJECTIVE

To investigate the effects of local vibration on muscle strength in healthy adults.

DATA SOURCES

The electronic databases PubMed, CINAHL, Scopus and Web of Science were searched using a combination of the following keywords: vibration, vibration therapy, power, maximal voluntary contraction, performance, rate of force development and vibratory exercise. In addition, the Medical Subject Headings 'vibration', 'strength' and 'exercise' were used. The bibliographical search was limited to articles published in English.

STUDY SELECTION

Trials that evaluated the effect of localised vibration on muscle strength in healthy humans were included.

DATA EXTRACTION

Two independent evaluators verified the quality of the selected studies using the PEDro Scale and the Cochrane Collaboration's tool for assessing the risk of bias. Muscle strength was calculated for each intervention.

RESULTS

In total, 29 full-text studies were assessed for eligibility. Eighteen studies did not match the inclusion criteria, and were excluded. The 11 studies included in this review had an average PEDro score of 5.36/10. Most of the studies reported significant improvements in muscle strength after the application of local vibration. There was considerable variation in the vibration training parameters and target muscle location.

CONCLUSIONS

The use of local vibration on the target muscle can enhance muscle strength in healthy adults. Further well-designed controlled studies are required to confirm the effect of local vibration training on muscle strength.

Presenting a Method to Improve Bone Quality Through Stimulation of Osteoporotic Mesenchymal Stem Cells by Low-Level Laser Therapy

OBJECTIVE

This review aims to present a method to improve bone quality through stimulation of osteoporotic mesenchymal stem cells (MSCs) by low-level laser therapy (LLLT).

BACKGROUND

Osteoporosis (OP) is characterized by decreased bone mass and bone strength, which results in an increased incidence of bone fractures. These fractures often lead to additional disability and mortality. Osteoporotic MSCs have reduced osteogenic differentiation when cultured in their standard differentiation media. LLLT has a biostimulatory effect on fibroblasts and osteoblasts. MSCs have the ability to generate cells of connective tissue lineages, which includes the bones. Recently, transplantation of in vitro cultured bone marrow (BM) MSCs into sites at risk for development of osteoporotic bone has resulted in improved bone structure.

METHODS

Comprehensive research was performed using PubMed, and biostimulatory effect of LLLT on bony cells and MSCs were studied.

RESULTS

LLLT can stimulate growth, proliferation, and differentiation of SCs in vitro and in vivo. This ability of LLLT is an essential prerequisite for performing experiments related to disease control in humans. Thus, laser-treated osteoporotic autologous BMMSCs may represent a promising therapeutic method to protect the bones in patients with OP and prevent fractures in these patients. Therefore, researchers hypothesize that transplantation of in vitro laser-treated autologous cultured osteoporotic BMMSCs that have the appropriate osteogenic phenotype into sites at risk for development of osteoporotic bone may result in improved bone structure. In this respect, investigators have successfully used LLLT to restore autologous osteoporotic MSCs in vitro. Subsequently, these cells have been differentiated into osteoblast cell lines with the use of laser treatment after which they were transplanted into osteoporotic animal models.

CONCLUSIONS

This technique might improve bone quality and structure. However, additional research must be undertaken to understand the underlying mechanisms of this treatment, validate its effectiveness, and assess the feasibility for clinical application of LLLT to treat MSCs in regeneration of osteoporotic bone.

Vibratory stimulation enhances thyroid epithelial cell function

The tissues of the body are routinely subjected to various forms of mechanical vibration, the frequency, amplitude, and duration of which can contribute both positively and negatively to human health. The vocal cords, which are in close proximity to the thyroid, may also supply the thyroid with important mechanical signals that modulate hormone production via mechanical vibrations from phonation. In order to explore the possibility that vibrational stimulation from vocalization can enhance thyroid epithelial cell function, FRTL-5 rat thyroid cells were subjected to either chemical stimulation with thyroid stimulating hormone (TSH), mechanical stimulation with physiological vibrations, or a combination of the two, all in a well-characterized, torsional rheometer-bioreactor. The FRTL-5 cells responded to mechanical stimulation with significantly (p<0.05) increased metabolic activity, significantly (p<0.05) increased ROS production, and increased gene expression of thyroglobulin and sodium-iodide symporter compared to un-stimulated controls, and showed an equivalent or greater response than TSH only stimulated cells. Furthermore, the combination of TSH and oscillatory motion produced a greater response than mechanical or chemical stimulation alone. Taken together, these results suggest that mechanical vibrations could provide stimulatory cues that help maintain thyroid function.

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Thyroid epithelial cells responded to mechanical vibrations similar to those from vocalization.

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This response was equivalent or greater compared to chemical stimulation.

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The combination of mechanical and chemical stimulation was synergistic.

•

It may be possible to influence thyroid function with mechanical vibrations.

Clinical applications of vibration therapy in orthopaedic practice

BACKGROUND

Vibration therapy (VT) has been proposed as an option to improve physical performance and reduce the negative effects of ageing on bone, muscles and tendons. Several discrepancies exist on the type of applications, frequency and magnitude. These differences reflex on the contradictory clinical results in literature. Aim of the present study is to carry on an exhaustive review to focus on technical options on the market, clinical applications in orthopaedic practice and expected outcomes.

METHODS

a literature review using the key words "vibration therapy" and "whole-body vibration" and "orthopaedics" was performed. After checking the available abstracts 71 full text articles were evaluated.

RESULTS

fifty-one articles focused on the effects of VT on muscles and tendons reporting ways of action and clinical outcomes. In a similar way 20 studies focused on the influence of VT on bone tissue with regard on ways of action and clinical trials.

CONCLUSIONS

VT provides anabolic mechanical signals to bone and musculo-tendinous system. The best effects seem to be achieved with devices that deliver low-intensity stimuli at high frequencies providing linear horizontal displacement.

Understanding Mechanobiology: Physical Therapists as a Force in Mechanotherapy and Musculoskeletal Regenerative Rehabilitation

Achieving functional restoration of diseased or injured tissues is the ultimate goal of both regenerative medicine approaches and physical therapy interventions. Proper integration and healing of the surrogate cells, tissues, or organs introduced using regenerative medicine techniques are often dependent on the co-introduction of therapeutic physical stimuli. Thus, regenerative rehabilitation represents a collaborative approach whereby rehabilitation specialists, basic scientists, physicians, and surgeons work closely to enhance tissue restoration by creating tailored rehabilitation treatments. One of the primary treatment regimens that physical therapists use to promote tissue healing is the introduction of mechanical forces, or mechanotherapies. These mechanotherapies in regenerative rehabilitation activate specific biological responses in musculoskeletal tissues to enhance the integration, healing, and restorative capacity of implanted cells, tissues, or synthetic scaffolds. To become future leaders in the field of regenerative rehabilitation, physical therapists must understand the principles of mechanobiology and how mechanotherapies augment tissue responses. This perspective article provides an overview of mechanotherapy and discusses how mechanical signals are transmitted at the tissue, cellular, and molecular levels. The synergistic effects of physical interventions and pharmacological agents also are discussed. The goals are to highlight the critical importance of mechanical signals on biological tissue healing and to emphasize the need for collaboration within the field of regenerative rehabilitation. As this field continues to emerge, physical therapists are poised to provide a critical contribution by integrating mechanotherapies with regenerative medicine to restore musculoskeletal function.

Effect of Low-Magnitude, High-Frequency Vibration Treatment on Retardation of Sarcopenia: Senescence-Accelerated Mouse-P8 Model

Sarcopenia-related falls and fall-related injuries in community-dwelling elderly people garnered more and more interest in recent years. Low-magnitude high-frequency vibration (LMHFV) was proven beneficial to musculoskeletal system and recommended for sarcopenia treatment. This study aimed to evaluate the effects of LMHFV on the sarcopenic animals and explore the mechanism of the stimulatory effects. Senescence-accelerated mouse P8 (SAMP8) mice at month 6 were randomized into control (Ctrl) and vibration (Vib) groups and the mice in the Vib group were given LMHFV (0.3 g, 20 min/day, 5 days/week) treatment. At months 0, 1, 2, 3, and 4 post-treatment, muscle mass, structure, and function were assessed. The potential proliferation capacity of the muscle was also evaluated by investigating satellite cells (SCs) pool and serum myostatin expression. At late stage, the mice in the Vib group showed higher muscle strength (month 4, p = 0.028). Generally, contractibility was significantly improved by LMHFV (contraction time [CT], p = 0.000; half-relaxation time [RT50], p = 0.000). Enlarged cross-sectional area of fiber type IIA was observed in the Vib group when compared with Ctrl group (p = 0.000). No significant difference of muscle mass was observed. The promotive effect of LMHFV on myoregeneration was reflected by suppressed SC pool reduction (month 3, p = 0.000; month 4, p = 0.000) and low myostatin expression (p = 0.052). LMHFV significantly improved the structural and functional outcomes of the skeletal muscle, hence retarding the progress of sarcopenia in SAMP8. It would be a good recommendation for prevention of the diseases related to skeletal muscle atrophy.

Osteocyte specific responses to soluble and mechanical stimuli in a stem cell derived culture model

Studying osteocyte behavior in culture has proven difficult because these embedded cells require spatially coordinated interactions with the matrix and surrounding cells to achieve the osteocyte phenotype. Using an easily attainable source of bone marrow mesenchymal stem cells, we generated cells with the osteocyte phenotype within two weeks. These "stem cell derived-osteocytes" (SCD-O) displayed stellate morphology and lacunocanalicular ultrastructure. Osteocytic genes Sost, Dmp1, E11, and Fgf23 were maximally expressed at 15 days and responded to PTH and 1,25(OH)2D3. Production of sclerostin mRNA and protein, within 15 days of culture makes the SCD-O model ideal for elucidating regulatory mechanisms. We found sclerostin to be regulated by mechanical factors, where low intensity vibration significantly reduced Sost expression. Additionally, this model recapitulates sclerostin production in response to osteoactive hormones, as PTH or LIV repressed secretion of sclerostin, significantly impacting Wnt-mediated Axin2 expression, via β-catenin signaling. In summary, SCD-O cells produce abundant matrix, rapidly attain the osteocyte phenotype, and secrete functional factors including sclerostin under non-immortalized conditions. This culture model enables ex vivo observations of osteocyte behavior while preserving an organ-like environment. Furthermore, as marrow-derived mesenchymal stem cells can be obtained from transgenic animals; our model enables study of genetic control of osteocyte behaviors.

Low-Magnitude, High-Frequency Vibration Fails to Accelerate Ligament Healing but Stimulates Collagen Synthesis in the Achilles Tendon

Background:

Low-magnitude, high-frequency vibration accelerates fracture and wound healing and prevents disuse atrophy in musculoskeletal tissues.

Purpose:

To investigate the role of low-magnitude, high-frequency vibration as a treatment to accelerate healing of an acute ligament injury and to examine gene expression in the intact Achilles tendon of the injured limb after low-magnitude, high-frequency vibration.

Study Design:

Controlled laboratory study.

Methods:

Complete surgical transection of the medial collateral ligament (MCL) was performed in 32 Sprague-Dawley rats, divided into control and low-magnitude, high-frequency vibration groups. Low-magnitude, high-frequency vibration started on postoperative day 2, and rats received vibration for 30 minutes a day for 12 days. All rats were sacrificed 2 weeks after the operation, and their intact and injured MCLs were biomechanically tested or used for histological analysis. Intact Achilles tendons from the injured limb were evaluated for differences in gene expression.

Results:

Mechanical testing revealed no differences in the ultimate tensile load or the structural stiffness between the control and vibration groups for either the injured or intact MCL. Vibration exposure increased gene expression of collagen 1 alpha (3-fold), interleukin 6 (7-fold), cyclooxygenase 2 (5-fold), and bone morphogenetic protein 12 (4-fold) in the intact Achilles tendon when compared with control tendons (P < .05).

Conclusion:

While no differences were observed in the mechanical or histological properties of the fully transected MCL after low-magnitude, high-frequency vibration treatment, significant enhancements in gene expression were observed in the intact Achilles tendon. These included collagen, several inflammatory cytokines, and growth factors critical for tendons.

Clinical Relevance:

As low-magnitude, high-frequency vibration had no negative effects on ligament healing, vibration therapy may be a useful tool to accelerate healing of other tissues (bone) in multitrauma injuries without inhibiting ligament healing. Additionally, the enhanced gene expression in response to low-magnitude, high-frequency vibration in the intact Achilles tendon suggests the need to further study its potential to accelerate tendon healing in partial injury or repair models.