Mechanical Stress Via Muscle Contractile Exercise Suppresses Atrophic Alterations of Bone-microstructure in Immobilized Rat Femurs.

OBJECTIVES: This study aimed to determine whether mechanical stress via muscle contractile exercise with belt electrode-skeletal muscle electrical stimulation (B-SES) device effectively prevents immobilization-induced bone atrophy. METHODS: Wistar rats were randomly divided into the control (CON) group, immobilization (IM) group (immobilized treatment only), HES and LES groups (immobilized treatment and high or low-intensity electrical muscular stimulation through B-SES device). Bilateral femurs were used for X-ray micro-CT and biomechanical tests. RESULTS: The maximum load value was significantly lower in the IM and HES groups than in the CON group and significantly higher in the LES group than in the IM group. The maximum crushing load was significantly lower in the IM, HES, and LES groups than in the CON group, and significantly higher in the HES and LES groups than that in the IM group. In micro-CT, the mechanical stress by B-SES device did not affect degenerative microstructural changes in the cortical bone, but prevented those changes in the cancellous bone. CONCLUSIONS: Applying mechanical stress via B-SES device suppressed the loss of cancellous bone density and degenerative microstructural changes caused by immobilization, which in turn suppressed the reduction of bone strength. From these findings, muscle contractile exercise may be effective in preventing immobilization-induced bone atrophy.

Inhibition of calcium/calmodulin-dependent protein kinase IV in arthritis: dual effect on Th17 cell activation and osteoclastogenesis.

OBJECTIVE: To investigate the role of calcium/calmodulin-dependent protein kinase IV (CaMK4) in the development of joint injury in a mouse model of arthritis and patients with RA. METHODS: Camk4-deficient, Camk4flox/floxLck-Cre, and mice treated with CaMK4 inhibitor KN-93 or KN-93 encapsulated in nanoparticles tagged with CD4 or CD8 antibodies were subjected to collagen-induced arthritis (CIA). Inflammatory cytokine levels, humoral immune response, synovitis, and T-cell activation were recorded. CAMK4 gene expression was measured in CD4+ T cells from healthy participants and patients with active RA. Micro-CT and histology were used to assess joint pathology. CD4+ and CD14+ cells in patients with RA were subjected to Th17 or osteoclast differentiation, respectively. RESULTS: CaMK4-deficient mice subjected to CIA displayed improved clinical scores and decreased numbers of Th17 cells. KN-93 treatment significantly reduced joint destruction by decreasing the production of inflammatory cytokines. Furthermore, Camk4flox/floxLck-Cre mice and mice treated with KN93-loaded CD4 antibody-tagged nanoparticles developed fewer Th17 cells and less severe arthritis. CaMK4 inhibition mitigated IL-17 production by CD4+ cells in patients with RA. The number of in vitro differentiated osteoclasts from CD14+ cells in patients with RA was significantly decreased with CaMK4 inhibitors. CONCLUSION: Using global and CD4-cell-targeted pharmacologic approaches and conditionally deficient mice, we demonstrate that CaMK4 is important in the development of arthritis. Using ex vivo cell cultures from patients with RA, CaMK4 is important for both Th17 generation and osteoclastogenesis. We propose that CaMK4 inhibition represents a new approach to control the development of arthritis.

Preventive Effect of an Intervention Program with Increased Physical Activity on the Development of Musculoskeletal Pain in Community-Dwelling Older Adults: A Randomized Controlled Trial.

OBJECTIVE: To examine whether compared with a program without increased physical activity, an intervention program with increased physical activity can prevent the development of musculoskeletal pain in community-dwelling older adults. DESIGN: Randomized controlled trial. SETTING: Japanese community. SUBJECTS: Seventy-nine older adults without musculoskeletal pain were randomized into two groups: an intervention group (n = 40) that engaged in increased physical activity and an exercise class and a control group (n = 39) that participated only in the exercise class. METHODS: The exercise class consisted of weekly 60-min sessions over 24 weeks. The program to increase physical activity required the participants to record their daily step counts using pedometers. The primary outcome was the development of musculoskeletal pain, and secondary outcomes were physical function, psychological status, cognitive function, and physical activity levels. RESULTS: Twenty-four weeks after the intervention, the intervention group had a significantly lower prevalence of musculoskeletal pain (12.8%) than the control group (32.4%; P = .040). A time-by-group interaction emerged for cognitive function (P = .01) and physical activity levels (P < .001), both of which favored the intervention group. The intervention group also showed greater improvement in psychological status 24 weeks after the intervention than the control group (P = .018). CONCLUSIONS: The intervention program with increased physical activity prevented the development of musculoskeletal pain and improved cognitive function, physical activity levels, and psychological status more effectively than the program without increased physical activity. Our intervention program may be an effective pain prevention approach for older adults. TRIAL REGISTRATION: UMIN000032768; registered on June 1, 2018.

Effects of low-level laser therapy on inflammatory symptoms in an arthritis rat model.

[Purpose] This study evaluated the effect of low-level laser therapy on inflammatory signs in an arthritis rat model as a foundation for elucidating the mechanism of the anti-inflammatory effect. [Materials and Methods] Eigteen Wistar rats were divided into three groups: group I (arthritis without low-level laser therapy), group II (arthritis with low-level laser therapy), and the control group (sham arthritis control). Arthritis was induced in the right knee by injecting a mixture of kaolin and carrageenan. Low-level laser therapy was continued for seven days after the onset of arthritis by 60 times of repeated irradiation for 10 seconds in the right knee joint area. The joint transverse diameter, pressure pain threshold in the affected knee joint, and mechanical paw withdrawal threshold at the distant site were evaluated the day before the injection and one, three, and seven days after the injection. Pathological changes were observed. [Results] Group II showed better improvement in swelling and pain in the affected knee joint and secondary hyperalgesia at the distance site when compared to group I. In group II, there was only mild infiltration of synovial cells, and the progression of arthritis was suppressed compared with that of group I. [Conclusion] Low-level laser therapy can mitigate swelling and inflammatory pain in the affected knee joint and prevent secondary hyperalgesia.

Myonuclear apoptosis via cleaved caspase-3 upregulation is related to macrophage accumulation underlying immobilization-induced muscle fibrosis.

INTRODUCTION/AIMS: Although macrophage accumulation plays a key role in the development of immobilization-induced muscle fibrosis, the underlying mechanisms remain unclear. Therefore, we focused on the alterations of myonuclear apoptosis via cleaved caspase-3, and investigated whether these changes may be related to macrophage accumulation. METHODS: Eight-week-old Wistar rats were divided into immobilization and control groups, and the soleus muscles were selected for analysis. RESULTS: The mRNA and protein expression of collagen and the number of CD11b-positive cells were significantly higher in the immobilized rats than in the control rats at 1 and 2 weeks. TdT-mediated dUTP nick end-labeling (TUNEL)-positive myonuclei counts in 1- and 2-week control rats were 0.2 ± 0.1 and 0.2 ± 0.5, whereas they were 1.0 ± 0.6 and 1.1 ± 0.5 in 1- and 2-week immobilized rats. The cleaved caspase-3 protein expressions in 1- and 2-week control rats were 0.2 ± 0.1 and 0.2 ± 0.1, whereas they were 0.5 ± 0.1 and 0.4 ± 0.2 in 1- and 2-week immobilized rats. TUNEL-positive myonuclei counts and cleaved caspase-3 protein expression were significantly higher in immobilized rats than in control rats at 1 and 2 weeks. The numbers of myonuclei in 1- and 2-week control rats were 2.8 ± 0.1 and 2.6 ± 0.4, whereas they were 2.2 ± 0.4 and 2.2 ± 0.2 in 1- and 2-week immobilized rats. The numbers of myonuclei were significantly lower in immobilized than in control rats at both time-points. DISCUSSION: Myonuclear apoptosis via the upregulation of cleaved caspase-3 might induce macrophage accumulation. These alterations are related to immobilization-induced muscle fibrosis.

Mechanisms underlying immobilization-induced muscle pain in rats.

INTRODUCTION: We investigated the mechanisms underlying immobilization-induced muscle pain in rats. METHODS: In rat skeletal muscle, pressure pain threshold (PPT) of the gastrocnemius muscle was measured, and nerve growth factor (NGF) level, peripheral nerve fiber density, macrophage number, and interleukin-1ß (IL-1ß) mRNA expression were examined. An NGF receptor inhibitor was injected intramuscularly to assess the relationship between PPT and NGF levels. RESULTS: Immobilization resulted in a decrease in PPT and increases in NGF level, C-fiber density, M1 macrophage number, and IL-1ß mRNA expression. Injection of NGF receptor inhibitor reversed the decrease in PPT. DISCUSSION: NGF upregulation may be a major contributor to immobilization-induced muscle pain. The increases in C-fiber density, M1 macrophage number, and IL-1ß mRNA expression may be related to immobilization-induced muscle pain.

Factors associated with muscle function in patients with hematologic malignancies undergoing chemotherapy.

PURPOSE: Muscle dysfunction such as loss of muscle mass and decreased muscle strength is often observed in patients with hematologic malignancies. However, specific factors associated with muscle function have not been identified. The purpose of this study was to identify significant factors affecting muscle function in patients with hematologic malignancies. METHODS: This was a cross-sectional, observational study. Eighty-eight inpatients with hematologic malignancies undergoing chemotherapy were recruited. Participants were evaluated for muscle thickness and isometric knee extensor strength as indicators of muscle function, physical activity, physical symptoms, psychological distress, and self-efficacy at the start date of rehabilitation. Multiple regression analysis with muscle function as the dependent variable and clinical information and other evaluation items as explanatory variables was performed. RESULTS: Lymphocyte count, the geriatric nutritional risk index, and physical activity were significant factors associated with muscle thickness, while physical activity and self-efficacy were significant factors associated with isometric knee extensor strength. CONCLUSIONS: Nutritional status, physical activity, and self-efficacy were significant factors associated with muscle function in patients with hematologic malignancies. Rehabilitation intervention focusing on improving physical activity and nutritional status should be considered necessary for enhancing muscle function in patients with hematologic malignancies.

Characteristics of muscle function and the effect of cachexia in patients with haematological malignancy.

OBJECTIVE: In this study, we investigated the muscle function of patients with haematological malignancy and healthy controls and examined the effect of cachexia on muscle function. METHODS: Seventy-one patients with haematological malignancy, hospitalised for chemotherapy, and 71 healthy controls underwent examination of skeletal muscle mass (SMM; total body and upper and lower limbs), handgrip strength and isometric knee extensor strength. Patients with haematological malignancy were divided into three groups based on Glasgow Prognostic Score: non-cachexia (n = 31), pre-cachexia (n = 23) and cachexia (n = 17) groups. The evaluation items were compared among the groups. RESULTS: Patients with haematological malignancy had lower SMM of the total body and lower limbs, handgrip strength and isometric knee extensor strength than healthy controls. There was no significant difference in SMM of the upper limbs among the groups. When classifying patients with haematological malignancy according to GPS, there was no significant difference among the three groups for any of the evaluation items. CONCLUSIONS: In patients with haematological malignancy, although significant muscle wasting and weakness were observed in the lower limbs, the effect of cachexia was minimal. The reduction in muscle function involved disuse syndrome, which accompanied a decline in physical activity.

Relationship between extensibility and collagen expression in immobilized rat skeletal muscle.

INTRODUCTION: This study investigated longitudinal changes in muscle extension and collagen expression in an immobilized rat soleus muscle, and assessed the relationship between both elements. METHODS: Soleus muscles of the control and immobilization groups (1, 2, 4, 8, and 12 weeks) were used for analysis of muscle extensibility and collagen expression. RESULTS: The slope value/physiological cross-sectional area (PCSA; a parameter for muscle extensibility) and hydroxyproline (a parameter for collagen expression) were significantly higher in the immobilization group than in the control group for all experimental time points. In the immobilization group, both factors were significantly higher at 4, 8, and 12 weeks than at 1 and 2 weeks after immobilization. A significant positive correlation was observed between the slope value/PCSA and hydroxyproline expression. DISCUSSION: The present study indicated that a decrease in muscle extensibility depended on collagen overexpression in immobilized rat soleus muscles. Muscle Nerve 57: 672-678, 2018.

Low-intensity exercise therapy with high frequency improves physical function and mental and physical symptoms in patients with haematological malignancies undergoing chemotherapy.

This study aimed to investigate the effects of low-intensity exercise therapy (LIET) on the physical and mental symptoms and functions in patients with haematological malignancies undergoing chemotherapy. Forty-four patients hospitalised for chemotherapy performed LIET. The exercise intensity of LIET was defined as achieving <40% of the predicted maximum heart rate calculated using the Karvonen formula. LIET consisted of aerobic and resistance training, which was carried out on weekdays. The intervention was omitted in the case of poor general health status and strong patient refusal. Muscular and physical function, activities of daily living (ADLs), psychological distress and quality of life (QOL) were evaluated upon initiation of rehabilitation and at discharge. Participants were divided into high- and low-frequency groups according to their LIET frequency. Two-way repeated-measures analysis of variance was used for statistical analysis. In the high-frequency group, muscle function was maintained, while physical function, ADLs, psychological distress and QOL were significantly improved. However, in the low-frequency group, muscle function of the lower limb was significantly reduced and no other improvement was observed. Low-intensity exercise therapy could be a potential treatment strategy for patients with haematological malignancies undergoing chemotherapy who are unable to perform mid- or high-intensity exercise.

Anatomical study of the articular branches innervated the hip and knee joint with reference to mechanism of referral pain in hip joint disease patients.

INTRODUCTION: Referred pain in the anterior knee joint is the most common symptom in hip disease patients. The development of referred pain is considered to be related to dichotomizing peripheral sensory fibers. However, no gross anatomical findings identify any dichotomizing fibers innervating both the hip and knee joints. We dissected the femoral and obturator nerves in human cadavers to investigate the distribution of the articular branches in the hip and knee joints. Fourteen embalmed left lower limbs from 14 Japanese adult cadavers (five from females, nine from males, average age 73.8 ± 14.1 years) were observed macroscopically. The articular branches of the femoral and obturator nerves were dissected at the anterior margin of the groin toward the thigh region. After dissections of the articular nerves of the hip joints, the femoral and obturator nerves were exposed from proximally to distally to identify the articular nerves of the knee joints. The branching pattern of the articular branches in the hip and knee joints was recorded. In six of 14 limbs (42.9%), the femoral nerve supplied articular branches to the anteromedial aspect of both the hip and knee joints. These articular branches were derived from the same bundle of femoral nerve. These gross anatomical findings suggested that dichotomizing peripheral sensory fibers innervate the hip and knee joints and these could relate to the referred pain confirmed in the anterior knee joints of patients with hip disease. Clin. Anat. 31:705-709, 2018. © 2018 Wiley Periodicals, Inc.

Cyclic muscle twitch contraction inhibits immobilization-induced muscle contracture and fibrosis in rats.

We investigated the effects of cyclic muscle twitch contraction caused by neuromuscular electrical stimulation (NMES) on immobilization-induced muscle contracture and fibrosis in rats. Twenty-nine rats were divided into control, immobilization, and immobilization with muscle contraction groups. The ankle joints of the immobilization and muscle contraction rats were fixed in full plantar flexion with a plaster cast for 4 weeks. In the muscle contraction group, cyclic muscle twitch contraction of the soleus muscle was induced using a commercial device (1 Hz, 4 ± 2 mA, 60 min/day, 5 times/week) with the ankle joint immobilized. The dorsiflexion range of ankle joint motion in the muscle contraction group was significantly greater than that in the immobilization group. The expressions of fibrosis-related genes (i.e., hypoxia inducible factor-1α, transforming growth factor-ß1, α-smooth muscle actin, and types I and III collagen) were significantly decreased in the muscle contraction group compared to the immobilization group. The fluorescence intensities of type I and type III collagen in the perimysium and endomysium in the muscle contraction group were significantly decreased compared to the immobilization group. These results suggest that cyclic muscle twitch contraction induced by NMES might alleviate skeletal muscle fibrosis, reducing immobilization-induced muscle contracture.

Development and progression of immobilization-induced skin fibrosis through overexpression of transforming growth factor-ß1 and hypoxic conditions in a rat knee joint contracture model.

PURPOSE: The purpose of this study was to investigate the pathology and mechanism of immobilization-induced skin fibrosis in a rat joint contracture model. METHODS: Rats were randomly divided into control and immobilization groups. In the immobilization groups, knee joints of the rats were immobilized for 1, 2, and 4 weeks. After each immobilization, skin was dissected. To assess fibrosis in the skin, the thickness and area of adipocytes and connective tissue fibers were measured. Myofibroblasts were analyzed by immunohistochemistry by using anti-α-SMA as a marker. Gene expression levels of type I and III collagen, TGF-ß1, and HIF-1α were measured by using RT-PCR. RESULTS: One week after immobilization, there was a marked increase in the area of connective tissue fibers in the immobilization group. Type I and type III collagen were significantly increased with prolonged immobilization. Higher numbers of α-SMA-positive cells were noted in the immobilized group at 2 and 4 weeks after immobilization. The expression level of TGF-ß1 mRNA in the immobilization group increased after one week of immobilization. In contrast, the expression level of HIF1-α mRNA increased after 2 weeks of immobilization, and a greater increase was seen at 4 weeks after immobilization. CONCLUSIONS: These results suggest that immobilization induces skin fibrosis with accumulation of types I and III collagen. These fibrotic changes may be evoked by upregulation of TGF-ß1 after one week of immobilization. Additionally, upregulation of HIF-1α may relate to skin fibrosis by accelerating the differentiation of fibroblasts to myofibroblasts starting at 2 weeks after immobilization.

Effects of a resistance training program performed with an interocclusal splint for community-dwelling older adults: a randomized controlled trial.

[Purpose] To examine whether resistance training for elderly community-dwellers performed with an interocclusal splint resulted in greater lower extremity muscle strength and better balance than resistance training performed without an interocclusal splint. [Subjects and Methods] Eighty-eight elderly persons using Japanese community day centers were randomly divided into two groups: an intervention group (n=45), which performed resistance training with an interocclusal splint; and a control group (n=43), which performed resistance training without an interocclusal splint. The resistance training program comprised a 40-min session performed twice a week for 12 weeks. Outcome measures were the chair stand test (CST), timed up and go test (TUG), and one-leg standing test (OLST). Assessments were conducted before the intervention and every 2 weeks after the start of the intervention. [Results] There was a significant group × time interaction for the OLST, with the intervention group showing significant improvement from 8 to 12 weeks compared to the control group. For the CST and TUG, no significant differences were found between the two groups throughout the 12 weeks. [Conclusion] Resistance training with an interocclusal splint improved the balance ability of elderly community-dwellers more effectively than resistance training without an interocclusal splint.

Haploinsufficiency of interferon regulatory factor 4 strongly protects against autoimmune diabetes in NOD mice.

AIMS/HYPOTHESIS: Interferon regulatory factor (IRF)4 plays a critical role in lymphoid development and the regulation of immune responses. Genetic deletion of IRF4 has been shown to suppress autoimmune disease in several mouse models, but its role in autoimmune diabetes in NOD mice remains unknown. METHODS: To address the role of IRF4 in the pathogenesis of autoimmune diabetes in NOD mice, we generated IRF4-knockout NOD mice and investigated the impact of the genetic deletion of IRF4 on diabetes, insulitis and insulin autoantibody; the effector function of T cells in vivo and in vitro; and the proportion of dendritic cell subsets. RESULTS: Heterozygous IRF4-deficient NOD mice maintained the number and phenotype of T cells at levels similar to NOD mice. However, diabetes and autoantibody production were completely suppressed in both heterozygous and homozygous IRF4-deficient NOD mice. The level of insulitis was strongly suppressed in both heterozygous and homozygous IRF4-deficient mice, with minimal insulitis observed in heterozygous mice. An adoptive transfer study revealed that IRF4 deficiency conferred disease resistance in a gene-dose-dependent manner in recipient NOD/severe combined immunodeficiency mice. Furthermore, the proportion of migratory dendritic cells in lymph nodes was reduced in heterozygous and homozygous IRF4-deficient NOD mice in an IRF4 dose-dependent manner. These results suggest that the levels of IRF4 in T cells and dendritic cells are important for the pathogenesis of diabetes in NOD mice. CONCLUSIONS/INTERPRETATION: Haploinsufficiency of IRF4 halted disease development in NOD mice. Our findings suggest that an IRF4-targeted strategy might be useful for modulating autoimmunity in type 1 diabetes.

Upregulation of interleukin-1ß/transforming growth factor-ß1 and hypoxia relate to molecular mechanisms underlying immobilization-induced muscle contracture.

INTRODUCTION: In this study we investigated the molecular mechanism underlying muscle contracture in rats. METHODS: The rats were divided into immobilization and control groups, and soleus muscles of the right and left sides were selected for analyses. RESULTS: The levels of CD11b and α-SMA protein, IL-1ß, and TGF-ß1 mRNA, and type I and III collagen protein and mRNA were significantly greater in the immobilization group than in the control group at all time-points. HIF-1α mRNA levels were significantly higher in the immobilization group at 4 weeks. Moreover, HIF-1α, α-SMA, and type I collagen levels were significantly higher at 4 weeks than at 1 and 2 weeks in the immobilization group. CONCLUSIONS: In the early stages of immobilization, upregulation of IL-1ß/TGF-ß1 via macrophages may promote fibroblast differentiation that could affect muscle contracture. The soleus muscle became hypoxic in the later stages of immobilization, suggesting that hypoxia influences the progression of muscle contracture.

Effectiveness of a balance-training program provided by qualified care workers for community-based older adults: A preliminary study.

The purpose of this study was to determine the effectiveness of a balance-training program provided by qualified care workers (QCWs) to community-based older adults attending day centers. Weekly balance training was conducted by QCWs working at day centers over a 6-month period. Fall risk factors, fear of falling, and physical function were compared between balance-training (n = 22) and control (n = 23) groups at baseline and after 6 months of intervention. Physical function assessments included the following: one-leg standing test, chair-standing test (CST), timed up-and-go test (TUGT), and a lower-extremity muscle strength test (LEST). Participants who underwent balance training significantly improved in the CST and LEST, and had reduced fear and risk of falling compared with the control group (p < 0.05). In the balance-training group, the TUGT was significantly better at 6 months than at baseline (p < 0.05). A balance-training program for community-dwelling older adults can be effectively implemented by QCWs.

Investigation and macroscopic anatomical study of referred pain in patients with hip disease.

[Purpose] The aim of this study was to examine the incidence and patterns of referred pain in patients with hip disease, as well as the nerve distribution in the hip and knee joints of 2 cadavers. [Subjects and Methods] A total of 113 patients with hip joint disease were included in the investigation. The incidence of regional pain and referred pain patterns were evaluated before and after arthroplasty. Two cadavers were macroscopically observed to verify the nerve innervation of the hip and knee joints. [Results] Anterior knee pain was observed preoperatively in 13.3% (in resting) and 33.6% (in motion) of the patients, which was comparable with the incidence of greater trochanter pain. In addition, the preoperative incidence rates of knee pain in resting and motion markedly decreased postoperatively. Of note is the remarkable incidence of pain radiating to the ventral lower limb. An anteromedial innervation was determined in the cadavers by the articular branches of the obturator and femoral nerve, which supply small branches to the knee joints. [Conclusion] Our results suggest that the distribution of the incidence of pain among the patients with hip disease is diverse owing to the sensory distribution of the femoral and obturator nerves.

Effects of Isometric Quadriceps Muscle Exercise with Visual and Auditory Feedback at 1 Year after Total Knee Arthroplasty.

OBJECTIVE: To examine the effect of isometric quadriceps exercises with visual and auditory feedback after total knee arthroplasty (TKA). METHODS: The sample included 41 patients from our previous study who could be followed up for 1 year after TKA. Patients in the intervention group performed isometric quadriceps exercises with visual and auditory feedback using the quadriceps training machine from the 2nd to the 14th day after TKA, whereas those in the control group underwent standard postoperative rehabilitation (without visual or auditory feedback during isometric quadriceps exercises) in the hospital. Patients were evaluated for pain intensity, timed up and go test (TUG) score, 10-m gait speed, 6-minute walking distance (6MWD), and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score 1 year after TKA. Additionally, exercise habits and responses to the International Physical Activity Questionnaire (IPAQ) were investigated. RESULTS: Pain intensity was significantly lower in the intervention group than in the control group. Greater improvements in the TUG test scores, 10-m gait speed, 6MWD, and WOMAC scores were observed in the intervention group. Walking activity, as recorded by the IPAQ, and the proportion of patients with exercise habits were significantly higher in the intervention group than in the control group. CONCLUSIONS: These results suggest that performing isometric quadriceps exercise with visual and auditory feedback using the quadriceps training machine has good effects, such as pain reduction, physical function improvement, exercise tolerance, and increased physical activity at 1 year after TKA.