Factors Related to Favorable Outcomes in Older Adults Undergoing Home-Visit Rehabilitation Therapy.

BACKGROUND: Increasing elderly population is a major health concern worldwide, requiring various at-home care services. The aim of home-visit rehabilitation therapy is to support at-home living of the elderly and to promote their participation in social activities. There is a paucity of data about the clinical conditions of this population that can contribute to the achievement of goals in-home visit rehabilitation therapy. AIM: This study aimed to clarify clinical variables that could be related to the achievement of goals in-home visit rehabilitation therapy. METHODS: We collected retrospective clinical data of the older adults who underwent home-visit rehabilitation therapy between July 2006 and June 2021. We searched the clinical variables of home-visit rehabilitation therapy users and their frequency of utilization of home-visit rehabilitation therapy services from the clinical record. The initial and final clinical variables evaluated in this study included the abilities of daily living, degree of being bedridden, dementia rating, and levels of support or long-term care. Those variables were evaluated by rehabilitation therapists and doctors. The users were divided into three groups according to the reason for terminating rehabilitation therapy: goal achievement (achieved group), aggravation of underlying disease (aggravated group), and treatment suspension because of their own/others' wish (suspended group). The clinical parameters concerning the rehabilitation program, care level, and activities of daily living were evaluated among the groups. The clinical parameters concerning the rehabilitation program, care level, and activities of daily living were statistically evaluated among those three groups, using the chi-square test and Kruskal-Wallis test. RESULTS: In the achieved, aggravated, and suspended groups, 45, 190, and 38 users were respectively enrolled. The aggravated group showed significantly higher final care level (p = 0.002), degree of being bedridden (p=0.001), and dementia rating (p = 0.017) and significantly lower Barthel index scores (p < 0.001) and Frenchay Activities Index scores (p = 0.001) than the achieved group. Persons requesting the therapy were significantly older adults themselves in the achieved group (p = 0.018). The therapy was significantly performed more than once per week in the achieved group (p = 0.018). CONCLUSIONS: Older adults undergoing self-motivated home-visit rehabilitation therapy more than once per week may contribute to the achievement of the goal.

Hypoxia suppresses glucose-induced increases in collective cell migration in vascular endothelial cell monolayers.

Blood glucose levels fluctuate during daily life, and the oxygen concentration is low compared to the atmosphere. Vascular endothelial cells (ECs) maintain vascular homeostasis by sensing changes in glucose and oxygen concentrations, resulting in collective migration. However, the behaviors of ECs in response to high-glucose and hypoxic environments and the underlying mechanisms remain unclear. In this study, we investigated the collective migration of ECs simultaneously stimulated by changes in glucose and oxygen concentrations. Cell migration in EC monolayer formed inside the media channels of microfluidic devices was observed while varying the glucose and oxygen concentrations. The cell migration increased with increasing glucose concentration under normoxic condition but decreased under hypoxic condition, even in the presence of high glucose levels. In addition, inhibition of mitochondrial function reduced the cell migration regardless of glucose and oxygen concentrations. Thus, oxygen had a greater impact on cell migration than glucose, and aerobic energy production in mitochondria plays an important mechanistic role. These results provide new insights regarding vascular homeostasis relative to glucose and oxygen concentration changes.

Interstitial-fluid shear stresses induced by vertically oscillating head motion lower blood pressure in hypertensive rats and humans.

The mechanisms by which physical exercise benefits brain functions are not fully understood. Here, we show that vertically oscillating head motions mimicking mechanical accelerations experienced during fast walking, light jogging or treadmill running at a moderate velocity reduce the blood pressure of rats and human adults with hypertension. In hypertensive rats, shear stresses of less than 1 Pa resulting from interstitial-fluid flow induced by such passive head motions reduced the expression of the angiotensin II type-1 receptor in astrocytes in the rostral ventrolateral medulla, and the resulting antihypertensive effects were abrogated by hydrogel introduction that inhibited interstitial-fluid movement in the medulla. Our findings suggest that oscillatory mechanical interventions could be used to elicit antihypertensive effects.

Microfluidic platform for the reproduction of hypoxic vascular microenvironments.

Vascular endothelial cells (ECs) respond to mechanical stimuli caused by blood flow to maintain vascular homeostasis. Although the oxygen level in vascular microenvironment is lower than the atmospheric one, the cellular dynamics of ECs under hypoxic and flow exposure are not fully understood. Here, we describe a microfluidic platform for the reproduction hypoxic vascular microenvironments. Simultaneous application of hypoxic stress and fluid shear stress to the cultured cells was achieved by integrating a microfluidic device and a flow channel that adjusted the initial oxygen concentration in a cell culture medium. An EC monolayer was then formed on the media channel in the device, and the ECs were observed after exposure to hypoxic and flow conditions. The migration velocity of the ECs immediately increased after flow exposure, especially in the direction opposite to the flow direction, and gradually decreased, resulting in the lowest value under the hypoxic and flow exposure condition. The ECs after 6-h simultaneous exposure to hypoxic stress and fluid shear stress were generally aligned and elongated in the flow direction, with enhanced VE-cadherin expression and actin filament assembly. Thus, the developed microfluidic platform is useful for investigating the dynamics of ECs in vascular microenvironments.

Stiffness of primordial germ cells is required for their extravasation in avian embryos.

Unlike mammals, primordial germ cells (PGCs) in avian early embryos exploit blood circulation to translocate to the somatic gonadal primordium, but how circulating PGCs undergo extravasation remains elusive. We demonstrate with single-cell level live-imaging analyses that the PGCs are arrested at a specific site in the capillary plexus, which is predominantly governed by occlusion at a narrow path in the vasculature. The occlusion is enabled by a heightened stiffness of the PGCs mediated by actin polymerization. Following the occlusion, PGCs reset their stiffness to soften in order to squeeze through the endothelial lining as they transmigrate. Our discovery also provides a model for the understanding of metastasizing cancer extravasation occurring mainly by occlusion.

Potential generation of nano-sized mist by passing a solution through dielectric barrier discharge.

Plasma medicine, a therapeutic technology that uses atmospheric-pressure plasma, is attracting much attention as an innovative tool for the medical field. Most of the plasma biomedical tools use direct effects, such as heat, optical stimulation, and reactive chemical species, on the lesion. Nanoparticulation techniques using indirect action by plasma, i.e., generation of electric fields, have the potential to be applied to promote transdermal absorption, where drugs pass through the barrier function of skin and penetrate into internal tissues. Here, we show a method to directly generate the nano-sized mist by passing a solution through the dielectric barrier discharge. This method enables us to produce the mist potentially in the nanometer size range for both water-based and oil-based solutions. Ease of mist generation was influenced by the plasma-induced changes in physical and chemical characteristics, including electrical conductivity, viscosity, and chemical species. We anticipate the developed method for nano-sized mist generation to provide a technique in the applications of the transdermal absorption system, including those related to pharmaceuticals and cosmetics.

P21-activated kinase regulates oxygen-dependent migration of vascular endothelial cells in monolayers.

The collective migration of vascular endothelial cells plays important roles in homeostasis and angiogenesis. Oxygen concentration in vivo, which is lower than in the atmosphere and changes due to diseases, is a key factor affecting the cellular dynamics of vascular endothelial cells. We previously reported that hypoxic conditions promote the internalization of vascular endothelial (VE)-cadherin, a specific cell-cell adhesion molecule, and increase the velocity of the collective migration of vascular endothelial cells. However, the mechanism through which cells regulate collective migration as affected by oxygen tension is not fully understood. Here, we investigated oxygen-dependent collective migration, focusing on intracellular protein p21-activated kinase (PAK) and hypoxia-inducing factor (HIF)-1α. A monolayer of human umbilical vein vascular endothelial cells (HUVECs) was formed in a microfluidic device with controllability of oxygen tension. The HUVECs were then exposed to various oxygen conditions in a range from 0.8% to 21% O2, with or without PAK inhibition or chemical stabilization of HIF-1α. Collective cell migration was measured by particle image velocimetry with time-lapse phase-contrast microscopic images. Localizations of VE-cadherin and HIF-1α were quantified by immunofluorescent staining. The collective migration of HUVECs varied in an oxygen-dependent fashion; the migration speed was increased by hypoxic exposure down to 1% O2, while it decreased under an extremely low oxygen tension of less than 1% O2. PAK inhibition suppressed the hypoxia-induced increase of the migration speed by preventing VE-cadherin internalization into HUVECs. A decrease in the migration speed was also obtained by chemical stabilization of HIF-1α, suggesting that excessive accumulation of HIF-1α diminishes collective cell migration. These results indicate that the oxygen-dependent variation of the migration speed of vascular endothelial cells is mediated by the regulation of VE-cadherin through the PAK pathway, as well as other mechanisms via HIF-1α, especially under extreme hypoxic conditions.

Hydrostatic pressure promotes endothelial tube formation through aquaporin 1 and Ras-ERK signaling.

Vascular tubulogenesis is tightly linked with physiological and pathological events in the living body. Endothelial cells (ECs), which are constantly exposed to hemodynamic forces, play a key role in tubulogenesis. Hydrostatic pressure in particular has been shown to elicit biophysical and biochemical responses leading to EC-mediated tubulogenesis. However, the relationship between tubulogenesis and hydrostatic pressure remains to be elucidated. Here, we propose a specific mechanism through which hydrostatic pressure promotes tubulogenesis. We show that pressure exposure transiently activates the Ras/extracellular signal-regulated kinase (ERK) pathway in ECs, inducing endothelial tubulogenic responses. Water efflux through aquaporin 1 and activation of protein kinase C via specific G protein-coupled receptors are essential to the pressure-induced transient activation of the Ras/ERK pathway. Our approach could provide a basis for elucidating the mechanopathology of tubulogenesis-related diseases and the development of mechanotherapies for improving human health.

Microfluidic platform for three-dimensional cell culture under spatiotemporal heterogeneity of oxygen tension.

Cells in a tumor microenvironment are exposed to spatial and temporal variations in oxygen tension due to hyperproliferation and immature vascularization. Such spatiotemporal oxygen heterogeneity affects the behavior of cancer cells, leading to cancer growth and metastasis, and thus, it is essential to clarify the cellular responses of cancer cells to oxygen tension. Herein, we describe a new double-layer microfluidic device allowing the control of oxygen tension and the behavior of cancer cells under spatiotemporal oxygen heterogeneity. Two parallel gas channels were located above the media and gel channels to enhance gas exchange, and a gas-impermeable polycarbonate film was embedded in the device to prevent the diffusion of atmospheric oxygen. Variations in oxygen tension in the device with the experimental parameters and design variables were investigated computationally and validated by using oxygen-sensitive nanoparticles. The present device can generate a uniform hypoxic condition at oxygen levels down to 0.3% O2, as well as a linear oxygen gradient from 3% O2 to 17% O2 across the gel channel within 15 min. Moreover, human breast cancer cells suspended in type I collagen gel were introduced in the gel channel to observe their response under controlled oxygen tension. Hypoxic exposure activated the proliferation and motility of the cells, which showed a local maximum increase at 5% O2. Under the oxygen gradient condition, the increase in the cell number was relatively high in the central mild hypoxia region. These findings demonstrate the utility of the present device to study cellular responses in an oxygen-controlled microenvironment.

Mechanical Regulation Underlies Effects of Exercise on Serotonin-Induced Signaling in the Prefrontal Cortex Neurons.

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-HT2A) 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-HT2A 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-HT2A receptor signaling in the PFC. Our findings indicate that neuronal cell function can be physiologically regulated by mechanical forces in the brain.

CNC-Milled Superhydrophobic Macroporous Monoliths for 3D Cell Culture.

High-strength macroporous monoliths can be obtained by the simple mixing of boehmite nanofiber aqueous acetate dispersions with methyltrimethoxysilane. On the boehmite nanofiber-polymethylsilsesquioxane monoliths, we can fabricate structures smaller than a millimeter in size by computer numerical control (CNC) milling, resulting in a machined surface that is superhydrophobic and biocompatible. Using this strategy, we fabricated a superhydrophobic multiwell plate that holds water droplets to produce 3D cell culture environments for various cell types. We expect these superhydrophobic monoliths to have future applications in 3D tissue construction.

Migration of vascular endothelial cells in monolayers under hypoxic exposure.

The hypoxic microenvironment existing in vivo is known to significantly affect cell morphology and dynamics, and cell group behaviour. Collective migration of vascular endothelial cells is essential for vasculogenesis and angiogenesis, and for maintenance of monolayer integrity. Although hypoxic stress increases vascular endothelial permeability, the changes in collective migration and intracellular junction morphology of vascular endothelial cells remain poorly understood. This study reveals the migration of confluent vascular endothelial cells and changes in their adherens junction, as reflected by changes in the vascular endothelial (VE)-cadherin distribution, under hypoxic exposure. Vascular endothelial monolayers of human umbilical vein endothelial cells (HUVECs) were formed in microfluidic devices with controllability of oxygen tension. The oxygen tension was set to either normoxia (21% O2) or hypoxia (<3% O2) by supplying gas mixtures into separate gas channels. The migration velocity of HUVECs was measured using particle image velocimetry with a time series of phase-contrast microscopic images of the vascular endothelial monolayers. Hypoxia inducible factor-1α (HIF-1α) and VE-cadherin in HUVECs were observed after exposure to normoxic or hypoxic conditions using immunofluorescence staining and quantitative confocal image analysis. Changes in the migration speed of HUVECs were observed in as little as one hour after exposure to hypoxic condition, showing that the migration speed was increased 1.4-fold under hypoxia compared to that under normoxia. Nuclear translocation of HIF-1α peaked after the hypoxic gas mixture was supplied for 2 h. VE-cadherin expression was also found to be reduced. When ethanol was added to the cell culture medium, cell migration increased. By contrast, by strengthening VE-cadherin junctions with forskolin, cell migration decreased gradually in spite the effect of ethanol to stimulate migration. These results indicate that the increase of cell migration by hypoxic exposure was attributable to loosening of intercellular junction resulting from the decrease of VE-cadherin expression.

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 massage on skeletal muscles, the molecular mechanisms behind are poorly understood. We have recently developed a simple device to apply local cyclical compression (LCC), which can generate intramuscular pressure waves with varying amplitudes. Using this device, we have demonstrated that LCC modulates inflammatory responses of macrophages in situ and alleviates immobilization-induced muscle atrophy. Here, we describe protocols for the optimization and application of LCC as a massage-like intervention against immobilization-induced inflammation and atrophy of skeletal muscles of mouse hindlimbs. The protocol that we have developed can be useful for investigating the mechanism underlying beneficial effects of physical exercise and massage. Our experimental system provides a prototype of the analytical approach to elucidate the mechanical regulation of muscle homeostasis, although further development needs to be made for more comprehensive studies.

Early-Stage Dynamics in Vascular Endothelial Cells Exposed to Hydrostatic Pressure.

Blood pressure is an important factor both in maintaining body homeostasis and in its disruption. Vascular endothelial cells (ECs) are exposed to varying degrees of blood pressure and therefore play an important role in these physiological and pathological events. However, the effect of blood pressure on EC functions remains to be elucidated. In particular, we do not know how ECs sense and respond to changes in hydrostatic pressure even though the hydrostatic pressure is known to affect the EC functions. Here, we hypothesized that the cellular responses, leading to the reported pressure effects, occur at an early stage of pressure exposure and observed the early-stage dynamics in ECs to elucidate mechanisms through which ECs sense and respond to hydrostatic pressure. We found that exposure to hydrostatic pressure causes an early actomyosin-mediated contraction of ECs without a change in cell morphology. This response could be caused by water efflux from the ECs following exposure to hydrostatic pressure. Although only a limited study, these findings do explain a part of the mechanism through which ECs sense and respond to hydrostatic pressure.

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

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 in situ 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 in situ 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 in vitro 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.

Fluid shear stress combined with shear stress spatial gradients regulates vascular endothelial morphology.

High shear stress (SS) causes local changes around arterial bifurcations, which are common sites for cerebral aneurysms. High SS and SS spatial gradient (SSG) are thought to play important roles in the pathology of cerebral aneurysms. However, whether SS and SSG independently affect the function and morphology of vascular endothelial cells (ECs) exposed to fluid flow remains unclear. This study evaluated the morphology of ECs exposed to various SS and SSG combinations. Confluent ECs were exposed to a SS of 2-60 Pa and a uniform SSG of 0, 5, 10, or 15 Pa mm-1 for 24 h. Although ECs exposed to lower levels of SS/SSG were not oriented or elongated in the direction of flow, they began to exhibit orientation, elongation, and development of actin stress fibers under the conditions of SS with a SSG when the SS exceeded a threshold value depending on the magnitude of SSG. Using a simplified computational model, we found that the presence of a SSG affects the strain field in ECs, resulting in a morphological response. SS combined with a SSG can alter the localization of SS mechano-sensing proteins along the strain field as a result of shear flow. Our results suggest that the magnitude of the relationship between SS and SSG plays an important role in regulating morphological changes in ECs in response to fluid flow by regulating EC polarity.

Endothelial monolayer permeability under controlled oxygen tension.

Endothelial permeability has been extensively investigated in the context of pathologies such as cancer and also in studies of drug delivery from the circulation. Hypoxia is a critical regulator of endothelial cell (EC) behavior and affects the barrier function of endothelial linings, yet its role has been little studied. This paper reveals the effect of hypoxia on the permeability of an EC monolayer by cellular experiments using a microfluidic device and a conventional cell culture dish. Human umbilical vein endothelial cells (HUVECs) were seeded into one microfluidic channel, creating an EC monolayer on each vertical surface of a collagen gel confined to a central chamber. Oxygen tension was regulated to produce normoxic (21% O2) or hypoxic (3% O2) conditions by the supply of gas mixtures of oxygen, carbon dioxide, and nitrogen at predefined ratios into channels fabricated into the device. Permeability of the EC monolayer quantified by analyzing diffusion of fluorescence-labelled dextrans into the collagen gel increases with barrier function loss by 6 hour hypoxic exposure, showing 11-fold and 4-fold increases for 70 kDa and 10 kDa dextrans, respectively, on average. Consistent with this, subsequent immunofluorescent staining and separate western blot analysis of HUVECs on a culture dish demonstrate loose cell-cell adhesion resulting from internalization of VE-cadherin under hypoxia. Thus, hypoxic stress increases endothelial permeability by altering cell-cell junction integrity.

Proliferation-Related Activity in Endothelial Cells Is Enhanced by Micropower Plasma.

Nonthermal plasma has received a lot of attention as a medical treatment technique in recent years. It can easily create various reactive chemical species (ROS) and is harmless to living body. Although plasma at gas-liquid interface has a potential for a biomedical application, the interactions between the gas-liquid plasma and living cells remain unclear. Here, we show characteristics of a micropower plasma with 0.018 W of the power input, generated at gas-liquid interface. We also provide the evidence of plasma-induced enhancement in proliferation activity of endothelial cells. The plasma produced H2O2, HNO2, and HNO3 in phosphate buffered saline containing Mg++ and Ca++ (PBS(+)), and their concentration increased linearly during 600-second discharge. The value of pH in PBS(+) against the plasma discharge time was stable at about 7.0. Temperature in PBS(+) rose monotonically, and its rise was up to 0.8°C at the bottom of a cell-cultured dish by the plasma discharge for 600 s. Short-time treatment of the plasma enhanced proliferation activity of endothelial cells. In contrast, the treatment of H2O2 does not enhance the cell proliferation. Thus, the ROS production and the nuclear factor-kappa B (NF-κB) activation due to the plasma treatment might be related to enhancement of the cell proliferation. Our results may potentially provide the basis for developing the biomedical applications using the gas-liquid plasma.

Haemodynamically dependent valvulogenesis of zebrafish heart is mediated by flow-dependent expression of miR-21.

Heartbeat is required for normal development of the heart, and perturbation of intracardiac flow leads to morphological defects resembling congenital heart diseases. These observations implicate intracardiac haemodynamics in cardiogenesis, but the signalling cascades connecting physical forces, gene expression and morphogenesis are largely unknown. Here we use a zebrafish model to show that the microRNA, miR-21, is crucial for regulation of heart valve formation. Expression of miR-21 is rapidly switched on and off by blood flow. Vasoconstriction and increasing shear stress induce ectopic expression of miR-21 in the head vasculature and heart. Flow-dependent expression of mir-21 governs valvulogenesis by regulating the expression of the same targets as mouse/human miR-21 (sprouty, pdcd4, ptenb) and induces cell proliferation in the valve-forming endocardium at constrictions in the heart tube where shear stress is highest. We conclude that miR-21 is a central component of a flow-controlled mechanotransduction system in a physicogenetic regulatory loop.