Neuromuscular Electrical Stimulation Induces Skeletal Muscle Fiber Remodeling and Specific Gene Expression Profile in Healthy Elderly

Residual effect of sequential 4-channel neuromuscular electrical stimulation evaluated by high-resolution manometry

BACKGROUND

High-resolution manometry (HRM) can quantify swallowing pathophysiology to evaluate the status of the pharynx. Sequential 4-channel neuromuscular electrical stimulation (NMES) was recently developed based on the normal contractile sequences of swallowing-related muscles. This study aimed to examine the effects of sequential 4-channel NMES for compensatory application during swallowing and to observe the residual effects after the application of NMES using HRM.

RESULTS

Sequential 4-channel NMES significantly improved the HRM parameters, with respect to the maximal pressure and area of the velopharynx (VP), maximal pressure and area of the mesopharynx (MP), and upper esophageal sphincter (UES) activation and nadir duration. Furthermore, the improvement in the pressure and area variables of the VP and MP showed a tendency to maintain even when measured after NMES, but there are no significant differences.

CONCLUSIONS

The present study suggests that the sequential 4-channel NMES application of the suprahyoid and infrahyoid muscles during swallowing improves the pressure, area, and time variables of the oropharynx, as measured by HRM, and it is likely that the effects may persist even after stimulation. Trial Registration Clinicaltrials.gov, registration number: NCT02718963 (initial release: 03/20/2016, actual study completion date: 06/24/2016, last release: 10/20/2020).

Electrical Stimulation for Treatment of Dysphagia Post Head Neck Cancer: A Systematic Review and Meta-Analysis

Introduction  Dysphagia induced by radiotherapy in the head and neck region comprises a challenging scenario and sometimes difficult rehabilitation due to the severity of the adverse effects. Some resources such as electrical stimulation have emerged as an alternative to complement the therapeutic process, but there is still no consensus on its use. Objective  The purpose of the present study was to evaluate, through a meta-analysis, the effect of electrical stimulation on the rehabilitation of dysphagia generated after head and neck cancer treatment. Data Synthesis  Four randomized controlled trials with a total of 146 participants were included. The age of the participants was 58.37 ± 1.8 years old and there was a predominance of males. The time to start the intervention ranged from 50.96 ± 40.12 months after cancer treatment. The intervention showed great heterogeneity regarding the positioning of the electrodes, parameters, duration of the stimulus, number of sessions, and intensity. No difference was identified in the following aspects: oral transit time, hyoid elevation, penetration and/or aspiration after electrostimulation. The quality of the evidence ranged from very low to moderate and high risk of bias. Conclusion In this meta-analysis, we found weak evidence for small and moderate swallowing benefits in patients after radiotherapy for head and neck cancer in short-term clinical trials.

The effect of neuromuscular electrical stimulation applied at different muscle lengths on muscle architecture and sarcomere morphology in rats

Neuromuscular electrical stimulation (NMES) is often used to increase muscle strength and functionality. Muscle architecture is important for the skeletal muscle functionality. The aim of this study was to investigate the effects of NMES applied at different muscle lengths on skeletal muscle architecture. Twenty-four rats were randomly assigned to four groups (two NMES groups and two control groups). NMES was applied on the extensor digitorum longus muscle at long muscle length, which is the longest and stretched position of the muscle at 170° plantar flexion, and at medium muscle length, which is the length of the muscle at 90° plantar flexion. A control group was created for each NMES group. NMES was applied for 8 weeks, 10 min/day, 3 days/week. After 8 weeks, muscle samples were removed at the NMES intervention lengths and examined macroscopically, and microscopically using a transmission electron microscope and streo-microscope. Muscle damage, and architectural properties of the muscle including pennation angle, fibre length, muscle length, muscle mass, physiological cross-sectional area, fibre length/muscle length, sarcomere length, sarcomere number were then evaluated. There was an increase in fibre length and sarcomere number, and a decrease in pennation angle at both lengths. In the long muscle length group, muscle length was increased, but widespread muscle damage was observed. These results suggest that the intervention of NMES at long muscle length can increase the muscle length but also causes muscle damage. In addition, the greater longitudinal increase in muscle length may be a result of the continuous degeneration-regeneration cycle.

Safety and effectiveness of neuromuscular electrical stimulation in cardiac surgery: A systematic review

BACKGROUND

Lack of mobilization and prolonged stay in the intensive care unit (ICU) are major factors resulting in the development of ICU-acquired muscle weakness (ICUAW). ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery, and may be a risk factor for prolonged duration of mechanical ventilation, associated with a higher risk of readmission and higher mortality. Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay. Neuromuscular electrical stimulation (NMES) is an alternative modality of exercise in patients with muscle weakness. A major advantage of NMES is that it can be applied even in sedated patients in the ICU, a fact that might enhance early mobilization in these patients.

AIM

To evaluate safety, feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.

METHODS

We performed a search on Pubmed, Physiotherapy Evidence Database (PEDro), Embase and CINAHL databases, selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials (RCTs) that included implementation of NMES in patients before after cardiac surgery. RCTs were assessed for methodological rigor and risk of bias via the PEDro. The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.

RESULTS

Ten studies were included in our systematic review, resulting in 703 participants. Almost half of them performed NMES and the other half were included in the control group, treated with usual care. Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery. Functional capacity was assessed in 8 studies via 6MWT or other indices, and improved only in 1 study before and in 1 after cardiac surgery. Nine studies explored the effects of NMES on muscle strength and function and, most of them, found increase of muscle strength and improvement in muscle function after NMES. NMES was safe in all studies without any significant complication.

CONCLUSION

NMES is safe, feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery, but has no significant effect on functional capacity.

Kinematic mechanism of the rehabilitative effect of 4-channel NMES: post-hoc analysis of a prospective randomized controlled study

The sequential 4-channel neuromuscular electrical stimulation (NMES), based on the normal contractile sequences of swallowing-related muscles, is a new rehabilitative treatment. The objective of this study was to explore the mechanism of the rehabilitative effect of the 4-channel NMES using kinematic analysis of videofluoroscopic swallowing study (VFSS) data. For this post-hoc analysis, we included a subset of participants from the prospective randomized controlled study on the clinical effectiveness of the sequential 4-channel NMES compared with that of the conventional 2-channel NMES. Seventeen subjects (11 and six in the 4- and 2-channel NMES groups, respectively) were eligible for the kinematic analysis of VFSS data. The hyoid bone movement was analyzed by evaluating the distance and time parameters with four peak points (A, B, C, D). The 4-channel NMES group showed significant improvement in vertical distances (A-C), horizontal distance (A-B, A-C), time interval (A-B-C) and total time, compared with their pretreatment data. The 2-channel NMES group showed significant improvements in time interval (A-B); however, the Euclidean distance (A-D) and mean velocity of the Euclidean distance (A-C) were significantly decreased. When the two groups were directly compared, the 4-channel group showed significantly greater improvement in horizontal distance (A-B), Euclidean distance (A-D), time interval (A-B-C), and mean velocity the Euclidean distance (A-D). The results in this study suggest that the sequential 4-channel NMES might lead to the physiologic circular movement of the hyoid bone during swallowing, and therefore be an effective treatment for dysphagia.Trial registration: Clinicaltrials.gov, registration number: NCT03670498.

A single session of EMS training induces long-lasting changes in circulating muscle but not cardiovascular miRNA levels: a randomized crossover study

Electromyostimulation (EMS) is used to maintain or build skeletal muscle and to increase cardiopulmonary fitness. Only limited data on the molecular mechanisms induced by EMS are available and effects on circulating microRNAs (c-miRNAs) have not been reported. This study aimed to evaluate whether EMS induces long-term changes in muscle- and cardiovascular-specific c-miRNA levels. Twelve healthy participants (33.0 ± 12.0 yr, 7 women) performed a 20-min whole body EMS training and a time- and intensity-matched whole body circuit training (CT) in random order. Blood samples were drawn pre-/posttraining and at 1.5, 3, 24, 48, and 72 h to determine creatine kinase (CK) and miRNA-21-5p, -126-3p, -133a-3p, -146a-5p, -206-3p, -222-3p, and -499a-5p levels. Muscular exertion was determined using an isometric strength test, and muscle soreness/pain was assessed by questionnaire. EMS participants reported higher muscle soreness 48 and 72 h postexercise and mean CK levels after EMS increased compared with CT at 48 and 72 h (time × group P ≤ 0.01). The EMS session induced a significant elevation of myomiR-206 and -133a levels starting at 1.5 and 3 h after exercise. Both miRNAs remained elevated for 72 h with significant differences between 24 and 72 h (time × group P ≤ 0.0254). EMS did not induce changes in cardiovascular miRNAs and no elevation in any miRNA was detected following CT. Time-course analysis of muscle damage marker CK and c-miR-133a and -206 levels did not suggest a common scheme (P ≥ 0.277). We conclude that a single EMS session induces specific long-lasting changes of miR-206 and miR-133 involved in muscle proliferation and differentiation. A single EMS session does not affect primary cardiovascular miRNA-21-5p, -126-3p, -146a-5p, and -222-3p levels.NEW & NOTEWORTHY Our study describes the long-term effects of electromyostimulation (EMS) on circulating miRNA levels. The observed increase of functional myomiR-206 and -133a levels over 72 h suggests long-lasting effects on muscle proliferation and differentiation, whereas cardiovascular miRNAs appear unaffected. Our findings suggest that circulating miRNAs provide useful insight into muscle regeneration processes after EMS and may thus be used to optimize EMS training effects.

Effect of Neuromuscular Electrical Stimulation Training on Control of Involuntary Muscular Torque and Stimulation Intensity in Older Adults

The purpose of this study was to examine the effects of a 4-week neuromuscular electrical stimulation (NMES) training regimen on involuntary torque output and electrical stimulation intensity in older adults. Twelve older adults (ages: 68.4 ± 6.5 years; men: n = 6, women: n = 6; weight: 158.6 ± 27.3 lbs; height: 65.2 ± 2.1 in) received submaximal intensity NMES to the quadriceps for 4 weeks to determine training-related changes in stimulation intensity and involuntary control of muscular torque during the NMES protocol. Two-way repeated measures ANOVAs were used to compare torque parameters and stimulation intensity between days and across protocol time bins. After training, stimulation intensity and torque increased over the course of the NMES protocol, while torque decreased during the protocol pre-training. These results suggest that muscular endurance of involuntary muscle contraction is increased with NMES training, and that stimulation intensity should be increased throughout the course of training to augment muscular torque output.

Prehabilitation in Cardiovascular Surgery: The Effect of Neuromuscular Electrical Stimulation (Randomized Clinical Trial)

OBJECTIVE

We aimed to determine the effects of prehabilitation with neuromuscular electrical stimulation (NMES) on muscle status and exercise capacity in patients before cardiac surgery.

METHODS

Preoperative elective cardiac surgery patients were randomly assigned to the NMES group or control group. Intervention in the NMES group was 7-10 sessions, whereas the control group carried out breathing exercises and an educational program. The outcome measures included a six-minute walk test (6MWT) and a muscle status assessment (knee extensor strength (KES), knee flexor strength (KFS), and handgrip strength (HS)) after the course of prehabilitation.

RESULTS

A total of 122 patients (NMES, n = 62; control, n = 60) completed the study. During the NMES course, no complications occurred. After the course prehabilitation KES, KFS, and 6MWT distance were significantly increased (all p < 0.001) in the NMES group compared to the control. There was no significant difference in HS before surgery.

CONCLUSIONS

A short-term NMES course before cardiac surgery is feasible, safe, and effective to improve preoperative functional capacity (six-minute walk distance) and the strength of stimulated muscles.

Basic mechanisms of peripheral nerve injury and treatment via electrical stimulation

Previous studies on the mechanisms of peripheral nerve injury (PNI) have mainly focused on the pathophysiological changes within a single injury site. However, recent studies have indicated that within the central nervous system, PNI can lead to changes in both injury sites and target organs at the cellular and molecular levels. Therefore, the basic mechanisms of PNI have not been comprehensively understood. Although electrical stimulation was found to promote axonal regeneration and functional rehabilitation after PNI, as well as to alleviate neuropathic pain, the specific mechanisms of successful PNI treatment are unclear. We summarize and discuss the basic mechanisms of PNI and of treatment via electrical stimulation. After PNI, activity in the central nervous system (spinal cord) is altered, which can limit regeneration of the damaged nerve. For example, cell apoptosis and synaptic stripping in the anterior horn of the spinal cord can reduce the speed of nerve regeneration. The pathological changes in the posterior horn of the spinal cord can modulate sensory abnormalities after PNI. This can be observed in cases of ectopic discharge of the dorsal root ganglion leading to increased pain signal transmission. The injured site of the peripheral nerve is also an important factor affecting post-PNI repair. After PNI, the proximal end of the injured site sends out axial buds to innervate both the skin and muscle at the injury site. A slow speed of axon regeneration leads to low nerve regeneration. Therefore, it can take a long time for the proximal nerve to reinnervate the skin and muscle at the injured site. From the perspective of target organs, long-term denervation can cause atrophy of the corresponding skeletal muscle, which leads to abnormal sensory perception and hyperalgesia, and finally, the loss of target organ function. The mechanisms underlying the use of electrical stimulation to treat PNI include the inhibition of synaptic stripping, addressing the excessive excitability of the dorsal root ganglion, alleviating neuropathic pain, improving neurological function, and accelerating nerve regeneration. Electrical stimulation of target organs can reduce the atrophy of denervated skeletal muscle and promote the recovery of sensory function. Findings from the included studies confirm that after PNI, a series of physiological and pathological changes occur in the spinal cord, injury site, and target organs, leading to dysfunction. Electrical stimulation may address the pathophysiological changes mentioned above, thus promoting nerve regeneration and ameliorating dysfunction.

Neuromuscular electrical stimulation in the intensive care unit prevents muscle atrophy in critically ill older patients: A retrospective cohort study

Critically ill patients in the intensive care unit (ICU) develop muscle atrophy and decreased physical function. Though neuromuscular electrical stimulation (NMES) therapy has been shown to be effective in preventing this, but its effect on older patients is unknown. To examine the course of critically ill older patients treated with NMES in the ICU and to define the impact of its use. A retrospective cohort study was conducted using older ICU patients (≥65 years) categorized into a control group (n = 20) and an NMES group (n = 22). For subgroup analysis, each group was further classified into pre-old age (65-74 years) and old age (≥75 years). The control group showed significant decrease in muscle thickness during ICU and hospital stay. The NMES group showed lower reduction in muscle thickness and showed decrease in muscle echo intensity during hospital stay, compared to the control group. NMES inhibited decrease in muscle thickness in the pre-old age group versus the old age group. The decreasing effect of NMES on echo intensity during hospital stay manifested only in the pre-old age group. We did not find much difference in physical functioning between the NMES and control groups. Lower limb muscle atrophy reduces in critically ill older patients (≥65 years) with NMES and is pronounced in patients aged < 75 years. The impact of NMES on the physical functioning of older patients in ICU needs to be further investigated.

Effects of Focused Vibrations on Human Satellite Cells

Skeletal muscle consists of long plurinucleate and contractile structures, able to regenerate and repair tissue damage by their resident stem cells: satellite cells (SCs). Reduced skeletal muscle regeneration and progressive atrophy are typical features of sarcopenia, which has important health care implications for humans. Sarcopenia treatment is usually based on physical exercise and nutritional plans, possibly associated with rehabilitation programs, such as vibratory stimulation. Vibrations stimulate muscles and can increase postural stability, balance, and walking in aged and sarcopenic patients. However, the possible direct effect of vibration on SCs is still unclear. Here, we show the effects of focused vibrations administered at increasing time intervals on SCs, isolated from young and aged subjects and cultured in vitro. After stimulations, we found in both young and aged subjects a reduced percentage of apoptotic cells, increased cell size and percentage of aligned cells, mitotic events, and activated cells. We also found an increased number of cells only in young samples. Our results highlight for the first time the presence of direct effects of mechanical vibrations on human SCs. These effects seem to be age-dependent, consisting of a proliferative response of cells derived from young subjects vs. a differentiative response of cells from aged subjects.

Neuromuscular or Sensory Electrical Stimulation for Reconditioning Motor Output and Postural Balance in Older Subjects?

Percutaneous electrical stimulation is used for reconditioning functional capabilities in older subjects. However, its optimal application depends on the specific physiological needs of the individual. Depending on whether his/her needs are related to motor function or sensory and central functions, the relevant modality of electrical stimulation differs significantly. In fact, there are two main modalities of electrical stimulation, that is, neuromuscular electrical stimulation (NMES) and sensory electrical stimulation (SES). NMES involves high-intensity currents (above the motor threshold) and provokes involuntary visible direct muscle contractions. With chronic application, the induced adaptations occur mainly at the neuromuscular function level and thus enhance muscle strength/power and motor output. SES involves low-intensity currents (below, at or only just above the sensory threshold), does not induce any visible muscle contraction and provides only sensory information. With chronic application, the induced adaptations occur at the level of potentiation and transmission of proprioceptive afferents and thus facilitate sensorimotor activity (movement and balance). Overall, SES is interesting for the improvement/maintenance of sensorimotor capabilities in non-frail older subjects while NMES is relevant to develop muscle strength/power and thus reduce the risk of falls due to a lack of muscle strength/power in frail older subjects.

NMES superimposed on movement is equally effective as heavy slow resistance training in patellar tendinopathy

OBJECTIVE

This study aimed at investigating the effectiveness of an 8-week training protocol, based on neuromuscular electrical stimulation of the quadriceps, which was superimposed onto voluntary exercise (NMES+), in comparison to a traditional heavy slow resistance training (HSRT), in individuals with patellar tendinopathy.

METHODS

Thirty-two physically active participants, aged: 33.6±10.2 years, were divided into two groups: NMES+ or HSRT. Maximal voluntary isometric contraction (MVIC) of knee extensor and flexor muscles, power during a countermovement jump (CMJ), and VISA-p questionnaire scores were recorded at the start(T0), 2-weeks(T1), 4-weeks(T2), 6-weeks(T3), 8-weeks(T4) and 4-months post-training (T5). Knee pain and rate of perceived exertion (RPE) were recorded at each training session with a 0-10 scale.

RESULTS

Knee pain was significantly lower in NMES+ compared to HSRT during all training sessions. No significant between-group differences were found for VISA-p scores and forces recorded during MVICs at T0,T1,T2,T3,T4 and T5. A significant increase of VISA-p and peak forces during MVIC was recorded across-time in both groups. No significant between-group or across-time differences were found for RPE and CMJ parameters.

CONCLUSIONS

NMES+ and HSRT were equally effective in decreasing tendinopathy symptoms and increasing strength, with NMES+ having the advantage to be a pain-free resistance training modality.

Sarcopenia as a comorbidity of cardiovascular disease

Sarcopenia, the lowered skeletal muscle mass, weakened skeletal muscle strength, and reduced physical performance with aging, is a component of frailty and high-risk factor for falls, resulting in an increase in mortality. In cardiovascular disease (CVD) patients, systemic inflammation, oxidative stress, overactivation of ubiquitin-proteasome system, endothelial dysfunction, lowering muscle blood flow, impaired glucose tolerance, hormonal changes, and physical inactivity possibly contribute to CVD-related sarcopenia. Prevalence of sarcopenia and osteosarcopenia, which is osteopenia and sarcopenia coexisting together, seems to be higher in CVD patients than in community-dwelling adults, suggesting the necessity of early diagnosis and prevention of CVD-related sarcopenia. Atrial stiffness, coronary artery calcification score, and serum vitamin D levels may be of help as the biomarkers to suspect sarcopenia, and renin-angiotensin-aldosterone system inhibitors may play a role in the medical prevention and treatment of CVD-related sarcopenia. There are few reports to convince the efficacies of dietary and antioxidant supplementation on sarcopenia at present, whereas aerobic and resistance training exercises have been recognized as an effective strategy to prevent and treat sarcopenia.

The wonder exerkines-novel insights: a critical state-of-the-art review

Several benefits can be acquired through physical exercise. Different classes of biomolecules are responsible for the cross-talk between distant organs. The secretome of skeletal muscles, and more widely the field of organokines, is ever-expanding. “Exerkine” has emerged as the umbrella term covering any humoral factors secreted into circulation by tissues in response to exercise. This review aims at describing the most interesting exerkines discovered in the last 3 years, which are paving the way for both physiological novel insights and potential medical strategies. The five exerkines identified all play a significant role in the healthy effect of exercise. Specifically: miR-1192, released by muscles and myocardium into circulation, by modulating cardioprotective effect in trained mice; miR-342-5p, located into exosomes from vascular endothelial cells, also a cardioprotective miRNA in trained young humans; apelin, released by muscles into circulation, involved in anti-inflammatory pathways and muscle regenerative capacity in rats; GDF-15, released into circulation from yet unknown source, whose effects can be observed on multiple organs in young men after a single bout of exercise; oxytocin, released by myoblasts and myotubes, with autocrine and paracrine functions in myotubes. The systemic transport by vesicles and the crosstalk between distant organs deserve a deep investigation. Sources, targets, transport mechanisms, biological roles, population samples, frequency, intensity, time and type of exercise should be considered for the characterization of existing and novel exerkines. The “exercise is medicine” framework should include exerkines in favor of novel insights for public health.

Molecular and neural adaptations to neuromuscular electrical stimulation; Implications for ageing muscle

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Muscle atrophy and functional declines observed with advancing age can be minimized via various NMES protocols.

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Animal models have shown that NMES induces motor axon regeneration and promotes axonal outgrowth and fibre reinnervation.

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The activation of BDNF-trkB contributes to promotion of nerve growth and survival and mediates neuroplasticity.

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NMES is able to regulate muscle protein homeostasis and elevate oxidative enzyme activity.

One of the most notable effects of ageing is an accelerated decline of skeletal muscle mass and function, resulting in various undesirable outcomes such as falls, frailty, and all-cause mortality. The loss of muscle mass directly leads to functional deficits and can be explained by the combined effects of individual fibre atrophy and fibre loss. The gradual degradation of fibre atrophy is attributed to impaired muscle protein homeostasis, while muscle fibre loss is a result of denervation and motor unit (MU) remodelling. Neuromuscular electrical stimulation (NMES), a substitute for voluntary contractions, has been applied to reduce muscle mass and functional declines. However, the measurement of the effectiveness of NMES in terms of its mechanism of action on the peripheral motor nervous system and neuromuscular junction, and multiple molecular adaptations at the single fibre level is not well described. NMES mediates neuroplasticity and upregulates a number of neurotropic factors, manifested by increased axonal sprouting and newly formed neuromuscular junctions. Repeated involuntary contractions increase the activity levels of oxidative enzymes, increase fibre capillarisation and can influence fibre type conversion. Additionally, following NMES muscle protein synthesis is increased as well as functional capacity. This review will detail the neural, molecular, metabolic and functional adaptations to NMES in human and animal studies.

Neuromuscular electrical stimulation in early rehabilitation of patients with postoperative complications after cardiovascular surgery: A randomized controlled trial

BACKGROUND

To evaluate the effectiveness of neuromuscular electrical stimulation (NMES) in early rehabilitation of patients with postoperative complications after cardiovascular surgery.

METHODS

37 patients (25 men and 12 women) aged 45 to 70 years with postoperative complications after cardiovascular surgery were included in the study. Eighteen patients underwent NMES daily since postoperative day 3 until discharge in addition to standard rehabilitation program (NMES group), and 19 patients underwent standard rehabilitation program only (non-NMES group). The primary outcome was the knee extensors strength at discharge in NMES group and in control. Secondary outcomes were the handgrip strength, knee flexor strength, and cross-sectional area (CSA) of the quadriceps femoris in groups at discharge.

RESULTS

Baseline characteristics were not different between the groups. Knee extensors strength at discharge was significantly higher in the NMES group (28.1 [23.8; 36.2] kg on the right and 27.45 [22.3; 33.1] kg on the left) than in the non-NMES group (22.3 [20.1; 27.1] and 22.5 [20.1; 25.9] kg, respectively; P < .001). Handgrip strength, knee flexor strength, quadriceps CSA, and 6 minute walk distance at discharge in the groups had no significant difference.

CONCLUSIONS

This pilot study shows a beneficial effect of NMES on muscle strength in patients with complications after cardiovascular surgery. The use of NMES showed no effect on strength of non-stimulated muscle, quadriceps CSA, and distance of 6-minute walk test at discharge.Further blind randomized controlled trials should be performed with emphasis on the effectiveness of NEMS in increasing muscle strength and structure in these patients.

Hyperbaric Oxygen Treatment Following Mid-Cervical Spinal Cord Injury Preserves Diaphragm Muscle Function

Oxidative damage to the diaphragm as a result of cervical spinal cord injury (SCI) promotes muscle atrophy and weakness. Respiratory insufficiency is the leading cause of morbidity and mortality in cervical spinal cord injury (SCI) patients, emphasizing the need for strategies to maintain diaphragm function. Hyperbaric oxygen (HBO) increases the amount of oxygen dissolved into the blood, elevating the delivery of oxygen to skeletal muscle and reactive oxygen species (ROS) generation. It is proposed that enhanced ROS production due to HBO treatment stimulates adaptations to diaphragm oxidative capacity, resulting in overall reductions in oxidative stress and inflammation. Therefore, we tested the hypothesis that exposure to HBO therapy acutely following SCI would reduce oxidative damage to the diaphragm muscle, preserving muscle fiber size and contractility. Our results demonstrated that lateral contusion injury at C3/4 results in a significant reduction in diaphragm muscle-specific force production and fiber cross-sectional area, which was associated with augmented mitochondrial hydrogen peroxide emission and a reduced mitochondrial respiratory control ratio. In contrast, rats that underwent SCI followed by HBO exposure consisting of 1 h of 100% oxygen at 3 atmospheres absolute (ATA) delivered for 10 consecutive days demonstrated an improvement in diaphragm-specific force production, and an attenuation of fiber atrophy, mitochondrial dysfunction and ROS production. These beneficial adaptations in the diaphragm were related to HBO-induced increases in antioxidant capacity and a reduction in atrogene expression. These findings suggest that HBO therapy may be an effective adjunctive therapy to promote respiratory health following cervical SCI.

Muscle Hypertrophy and Architectural Changes in Response to Eight-Week Neuromuscular Electrical Stimulation Training in Healthy Older People

Loss of muscle mass of the lower limbs and of the spine extensors markedly impairs locomotor ability and spine stability in old age. In this study, we investigated whether 8 w of neuromuscular electrical stimulation (NMES) improves size and architecture of the lumbar multifidus (LM) and vastus lateralis (VL) along with locomotor ability in healthy older individuals. Eight volunteers (aged 65 ≥ years) performed NMES 3 times/week. Eight sex- and age-matched individuals served as controls. Functional tests (Timed Up and Go test (TUG) and Five Times Sit-to-Stand Test (FTSST)), VL muscle architecture (muscle thickness (MT), pennation angle (PA), and fiber length (FL)), along with VL cross-sectional area (CSA) and both sides of LM were measured before and after by ultrasound. By the end of the training period, MT and CSA of VL increased by 8.6% and 11.4%, respectively. No significant increases were observed in FL and PA. LM CSA increased by 5.6% (left) and 7.1% (right). Interestingly, all VL architectural parameters significantly decreased in the control group. The combined NMES had a large significant effect on TUG (r = 0.50, p = 0.046). These results extend previous findings on the hypertrophic effects of NMES training, suggesting to be a useful mean for combating age-related sarcopenia.

Dynamin-related protein-1 promotes lung cancer A549 cells apoptosis through the F-actin/bax signaling pathway

Dynamin-related protein-1 (Drp1) has been found to be associated with cell death. The role of Drp1 in A549 cells death has not been explored. In this study, adenovirus-mediated Drp1 overexpression was used to investigate the influence of Drp1 on A549 cell viability with a focus on F-actin and Bax. Cell viability, protein expression, oxygen consumption, energy metabolism, and growth rate were measured through ELISA, qPCR, western blots and pathway analysis. Our results indicated that Drp1 overexpression promoted A549 cell death through apoptosis. Mechanistically, cytoskeletal F-actin was impaired and Bax expression was elevated in response to Drp1 overexpression. Besides, energy metabolism was reduced and oxygen consumption was interrupted. Therefore, our results demonstrated that A549 cell viability, apoptosis and growth were regulated by the Drp1/F-actin/Bax signaling pathways. These data explain a new role played by Drp1 in regulating cell viability and also provide a potential target to affect the progression of lung cancer through induction of cell death.