application-consistent-massage-like-perturbations-on-mouse-calves

Application of Consistent Massage-Like Perturbations on Mouse Calves and Monitoring the Resulting Intramuscular Pressure Changes

Massage is generally recognized to be beneficial for relieving pain and inflammation. Although previous studies have reported anti-inflammatory effects of ...

application-passive-head-motion-to-generate-defined-accelerations-at

Application of Passive Head Motion to Generate Defined Accelerations at the Heads of Rodents

Exercise is widely recognized as effective for various diseases and physical disorders, including those related to brain dysfunction. However, molecular ...

National Rehabilitation Center for Persons with disabilities

Thermal discomfort among lower-limb prosthesis wearers is prevalent with social and medical consequences.

A pilot study towards long-term thermal comfort research for lower-limb prosthesis wearers.

Physical inactivity gives rise to numerous diseases and organismal dysfunctions, particularly those related to aging. Musculoskeletal disorders including muscle atrophy, which can result from a sedentary lifestyle, aggravate locomotive malfunction and evoke a vicious circle leading to severe functional disruptions of vital organs such as the brain and cardiovascular system. Although the significance of physical activity is evident, molecular mechanisms behind its beneficial effects are poorly understood. Here, we show that massage-like mechanical interventions modulate immobilization-induced pro-inflammatory responses of macrophages  and alleviate muscle atrophy. Local cyclical compression (LCC) on mouse calves, which generates intramuscular pressure waves with amplitude of 50 mmHg, partially restores the myofiber thickness and contracting forces of calf muscles that are decreased by hindlimb immobilization. LCC tempers the increase in the number of cells expressing pro-inflammatory proteins, tumor necrosis factor-α and monocyte chemoattractant protein-1 (MCP-1), including macrophages  The reversing effect of LCC on immobilization-induced thinning of myofibers is almost completely nullified when macrophages recruited from circulating blood are depleted by administration of clodronate liposomes. Furthermore, application of pulsatile fluid shear stress, but not hydrostatic pressure, reduces the expression of MCP-1 in macrophages  Together with the LCC-induced movement of intramuscular interstitial fluid detected by µCT analysis, these results suggest that mechanical modulation of macrophage function is involved in physical inactivity-induced muscle atrophy and inflammation. Our findings uncover the implication of mechanosensory function of macrophages in disuse muscle atrophy, thereby opening a new path to develop a novel therapeutic strategy utilizing mechanical interventions.

Local cyclical compression modulates macrophage function  and alleviates immobilization-induced muscle atrophy.

The shearing force acting upon the contacting surface of the buttocks while seated in a wheelchair has been linked to the development of pressure ulcers. However, the actual causative factors have not been examined in detail. In an attempt to clarify the nature of this problem, we developed a specific measurement system. In preparation for future clinical applications, we conducted preliminary testing in non-disabled individuals. As a result, we were able to discover a number of issues related to this system and our measurement methods. Although we only evaluated a limited number of typical sitting postures, we were able to record the buttocks shearing force reference values for non-disabled individuals. Our results suggest that regardless of posture, a backward-directed shearing force occurs below the ischial tuberosity in non-disabled individuals in seated positions. This force seemed to increase as the individual leaned forward. Meanwhile, tilting the torso to one side seemed to be associated with an increase in the shearing force working in the opposite direction. We hope that these findings can be utilized for reference purposes in future research among non-disabled individuals.

The relationship between torso inclination and the shearing force of the buttocks while seated in a wheelchair: Preliminary research in non-disabled individuals.

Mechanical forces are known to be involved in various biological processes. However, it remains unclear whether brain functions are mechanically regulated under physiological conditions. Here, we demonstrate that treadmill running and passive head motion (PHM), both of which produce mechanical impact on the head, have similar effects on the hallucinogenic 5-hydroxytryptamine (5-HT) receptor subtype 2A (5-HT) signaling in the prefrontal cortex (PFC) of rodents. PHM generates interstitial fluid movement that is estimated to exert shear stress of a few pascals on cells in the PFC. Fluid shear stress of a relevant magnitude on cultured neuronal cells induces ligand-independent internalization of 5-HT receptor, which is observed in mouse PFC neurons after treadmill running or PHM. Furthermore, inhibition of interstitial fluid movement by introducing polyethylene glycol hydrogel eliminates the effect of PHM on 5-HT receptor signaling in the PFC. Our findings indicate that neuronal cell function can be physiologically regulated by mechanical forces in the brain.

ArticleTotal : 2	Year
Publication title Cited by 5	2019
Publication title Cited by 1	2022

Article	Year
A pilot study towards long-term thermal comfort research for lower-limb prosthesis wearers. Prosthetics and orthotics international\| PubMed ID: 30080114	2019
Local cyclical compression modulates macrophage function and alleviates immobilization-induced muscle atrophy. Clinical science (London, England : 1979)\| PubMed ID: 30209036	2018
The relationship between torso inclination and the shearing force of the buttocks while seated in a wheelchair: Preliminary research in non-disabled individuals. Assistive technology : the official journal of RESNA\| PubMed ID: 30500299	2020
Mechanical Regulation Underlies Effects of Exercise on Serotonin-Induced Signaling in the Prefrontal Cortex Neurons. iScience\| PubMed ID: 32062453	2020

Atsushi Takashima

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