Relationships between muscle mass, intramuscular adipose and fibrous tissues of the quadriceps, and gait independence in chronic stroke survivors: a cross-sectional study

Change in body weight is positively related to the change in muscle mass of the quadriceps in older inpatients with severely low BMI according to the GLIM criteria

BACKGROUND & AIMS

Body weight is one of the essential indicators of nutritional status, and body weight management is vital in nutritional care. In addition, low body mass index (BMI) was included as a phenotypic criterion in the Global Leadership Initiative on Malnutrition (GLIM) criteria. Furthermore, low BMI has been used in grading the severity of malnutrition (moderate or severe malnutrition) in the GLIM criteria. A recent cross-sectional study reported that muscle mass of the quadriceps in older inpatients with severely low BMI is less than those of older inpatients with moderately low BMI and non-low BMI. However, the longitudinal relationship between body weight and muscle mass of the quadriceps in older inpatients in each BMI category according to the GLIM criteria remains unclear. This study aimed to examine the longitudinal relationship between body weight and muscle mass of the quadriceps in older inpatients in each BMI category according to the GLIM criteria.

METHODS

This retrospective cohort study included 179 older inpatients (aged ≥ 70 years) (median [IQR] age: 84.0 [79.0-89.0]). The period of this study was between January 2017 and March 2020. In accordance with the cut-off value of a low BMI for patients aged ≥ 70 years in the Asian population according to the GLIM criteria, the participants were divided into the following three groups: the severely low BMI group (< 17.8 kg/m2) (n = 47), moderately low BMI group (≥ 17.8 to < 20.0 kg/m2) (n = 38), and non-low BMI group (≥ 20.0 kg/m2) (n = 94). The medians (IQR) of the length of hospital stay of the severely low BMI, moderately low BMI, and non-low BMI groups were 71.0 (49.0-98.0) days, 71.0 (50.0-98.0) days, and 50.5 (36.5-103.0) days, respectively. The primary outcome was a change in muscle mass of the quadriceps. The muscle mass of the quadriceps was examined using ultrasound images (i.e., quadriceps thickness). The changes in quadriceps thickness and body weight were calculated by subtracting the quadriceps thickness and body weight at admission from those values at discharge. Multiple linear regression analysis adjusting for confounding factors was used to determine whether the change in body weight was independently and significantly related to the change in quadriceps thickness in the severely low BMI, moderately low BMI, and non-low BMI groups.

RESULTS

The means (SD) of the change in quadriceps thickness of the severely low BMI group, moderately low BMI group, and non-low BMI group were 0.0 ± 0.3 cm, 0.1 ± 0.3 cm, and 0.1 ± 0.5 cm, respectively. The means of the change in body weight in those groups were 0.4 ± 2.8 kg, - 1.1 ± 2.7 kg, and - 1.3 ± 4.3 kg, respectively. In the severely low BMI group, the change in body weight (β = 0.34, p = 0.006) and quadriceps thickness at admission (β = -0.62, p < 0.001) were significantly and independently related to the change in quadriceps thickness (R2 = 0.645, f2 = 1.817, statistical power = 1.000). In the moderately low BMI and non-low BMI groups, there were no factors that were significantly and independently related to the change in quadriceps thickness.

CONCLUSIONS

The results of this study suggest that change in body weight is positively related to the change in muscle mass of the quadriceps in older inpatients with severely low BMI according to the GLIM criteria. These results imply the importance of body weight management for older inpatients with severely low BMI perspective from the muscle mass of the quadriceps.

Relationship of serial muscle ultrasound of rectus femoris and ambulatory recovery in patients with acute incomplete spinal cord injury: A prospective observational study

CONTEXT/OBJECTIVE

To investigate the change in serial muscle ultrasound of rectus femoris of patients with incomplete spinal cord injury (SCI) performed within 2 months after SCI during acute rehabilitation, and the relationship with functional outcomes at 1 year post-injury.

DESIGN

Prospective observational study.

SETTING

Inpatient multi-speciality tertiary rehabilitation center in Singapore.

PARTICIPANTS

Fifty-four patients with incomplete SCI, defined as American Spinal Injury Association Impairment Scale B-D, with SCI above L2, were recruited from March 2020 to June 2021. Serial muscle ultrasound of the rectus femoris thickness and echo intensity were obtained at 1 week post-injury and after 2 months via standardized protocols.

OUTCOME MEASURES

Functional Independence Measure (FIM) motor score, Lower Extremity Motor Score (LEMS), Spinal Cord Independence Measure III (SCIM III) indoor mobility component and Walking Index for Spinal Cord Injury II (WISCI II) were assessed in the first week post-admission and at 1 year.

RESULTS

There was a significant positive correlation between change in rectus femoris muscle thickness over 2 months and FIM motor score (P < 0.001), LEMS (P < 0.001), SCIM III indoor mobility component (P < 0.001) and WISCI II (P < 0.001) at 1 year. For the change in echo intensity over 2 months, there was a significantly negative correlation with FIM motor score (P = 0.002), LEMS (P = 0.002), SCIM III indoor mobility component (P = 0.001) and WISCI II (P = 0.001) at 1 year.

CONCLUSION

The findings suggest that ultrasonographic serial assessment of rectus femoris muscle thickness and echo intensity during rehabilitation may be useful for determining the long-term functional outcomes in patients with incomplete SCI.

The relationship between sarcopenic obesity and changes in quadriceps muscle thickness and echo intensity in patients with stroke

BACKGROUND

Research findings on skeletal muscle degeneration in post-stroke sarcopenic obesity are limited. Thus, this study aimed to investigate the association between post-stroke sarcopenic obesity and quantitative and qualitative changes in skeletal muscles.

METHODS

This was a cross-sectional study conducted on patients with stroke admitted to the convalescent rehabilitation ward. For skeletal muscle assessment, an ultrasound system was used to measure quadriceps muscle thickness and echo intensity (QMT and QEI) on the paretic and non-paretic sides. Sarcopenic obesity was defined as the presence of both sarcopenia and obesity. Multiple regression analysis was performed to determine the relationships between sarcopenic obesity and QMT and QEI.

RESULTS

A total of 130 patients with stroke were included in this study (mean age: 69.4 ± 12.7 years). The prevalence of sarcopenic obesity was 23.1%. The multiple regression analysis showed that sarcopenic obesity was significantly negatively associated with QMT on both the paretic and non-paretic sides (paretic side: β =  -0.28, p < 0.001; non-paretic side: β =  -0.37, p < 0.001) and significantly positively associated with QEI (paretic side β = 0.21, p = 0.034; non-paretic side: β = 0.20, p = 0.029).

CONCLUSIONS

Post-stroke sarcopenic obesity was independently associated with quantitative and qualitative changes in skeletal muscles on both the paretic and non-paretic sides.

Increased intramuscular adipose tissue of the quadriceps at admission is more strongly related to activities of daily living recovery at discharge compared to muscle mass loss in older patients with aspiration pneumonia

BACKGROUND

Recent studies reported that an increase in intramuscular adipose tissue of the quadriceps in older patients negatively affects the recovery of activities of daily living (ADL) more than the loss of muscle mass. However, whether intramuscular adipose tissue of the quadriceps in older patients with aspiration pneumonia is related to ADL recovery remains unclear. This study aimed to determine the relationship between intramuscular adipose tissue of the quadriceps and ADL recovery in older patients with aspiration pneumonia.

METHODS

Thirty-nine older inpatients who were diagnosed with aspiration pneumonia participated in this prospective study. The main outcome of this study was ADL at discharge. ADL were assessed using the Barthel Index (BI). The intramuscular adipose tissue and muscle mass of the quadriceps were evaluated at admission using echo intensity and muscle thickness observed on ultrasound images. A multiple linear regression analysis was performed to confirm whether the quadriceps echo intensity was related to the BI score at discharge, even after adjusting for confounding factors.

RESULTS

The medians [interquartile range] of the BI score at admission and discharge were 15.0 [0.0-35.0] and 20.0 [5.0-55.0], respectively. The BI score at discharge was significantly higher than that at admission (p = 0.002). The quadriceps echo intensity (β =  - 0.374; p = 0.036) and BI score at admission (β = 0.601; p < 0.001) were independently and significantly related to the BI score at discharge (R2 = 0.718; f2 = 2.546; statistical power = 1.000). In contrast, the quadriceps thickness (β =  - 0.216; p = 0.318) was not independently and significantly related to the BI score at discharge.

CONCLUSIONS

Increased intramuscular adipose tissue of the quadriceps at admission is more strongly and negatively related to ADL recovery at discharge than the loss of muscle mass among older patients with aspiration pneumonia. Interventions targeting the intramuscular adipose tissue of the quadriceps may improve ADL among these patients.

Optimal resistance exercise training parameters for stroke recovery: A protocol for a systematic review

BACKGROUND

Stroke impacts nearly 14 million people annually. Muscle strength and physical function are often affected by stroke and important determinants of stroke recovery. Resistance exercise training (RT) has been shown to improve muscle strength, but RT prescriptions may be suboptimal for other aspects of stroke recovery. Parameters such as frequency, intensity, type, and duration may influence the effectiveness of RT interventions but have not been systematically evaluated.

OBJECTIVES

1) To determine the effects of RT on stroke recovery, and 2) to examine the influence of RT parameters on intervention effects.

ELIGIBILITY CRITERIA

Randomized controlled trials examining the effects of RT will be eligible for this systematic review if they: 1) included only adults with stroke or transient ischemic attack, 2) compared RT to no exercise or usual care, and 3) did not apply a co-intervention.

STUDY SELECTION

Eight databases (MEDLINE, EMBASE, EMCARE, AMED, PsychINFO, CINAHL, SPORTDiscus, and Web of Science) and 2 clinical trials registries (ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform) will be searched from inception. Two independent pairs of authors will compare titles, abstracts, and full-text reports against the eligibility criteria. Conflicts will be resolved by consensus or third author.

MAIN OUTCOME MEASURES

The construct of interest is stroke recovery. An advisory group of clinicians, researchers, and partners with lived experience of stroke will be consulted to determine specific outcome measures of interest, and to rank their relative importance. We expect to include measures of physical function, strength, cognition, and quality of life. Random-effects meta-analyses will be used to pool results for each outcome across studies, and RT parameters (frequency, intensity, type, and duration) will be used as covariates in meta-regression analyses.

CONCLUSION

The results of this review will inform the optimal RT prescription parameters for promoting stroke recovery.

Increase in protein intake is related to decreasing intramuscular adipose tissue of the quadriceps in older inpatients: A longitudinal study

BACKGROUND & AIM

Several randomized controlled trials indicated that an increase in protein intake decreases intramuscular adipose tissue of the thigh in mobility-limited or pre-frail older persons and stroke patients. However, whether the increase in protein intake in older inpatients is related to decreasing intramuscular adipose tissue remains unclear. The aim of this study was to examine the longitudinal relationship between intramuscular adipose tissue of the quadriceps and protein intake in older inpatients.

METHODS

This longitudinal study included 193 older inpatients (aged ≥65 years) (median [IQR] age: 83.0 [77.0-88.0]). The primary outcomes were changes in intramuscular adipose tissue of the quadriceps and protein intake. Intramuscular adipose tissue and muscle mass of the quadriceps were examined using ultrasound images (i.e., quadriceps echo intensity and thickness). The changes in quadriceps echo intensity and protein intake were calculated by subtracting the quadriceps echo intensity and protein intake at admission from those values at discharge. Multiple linear regression analysis adjusting for confounding factors was used to determine whether the change in protein intake was independently and significantly related to changes in quadriceps echo intensity and thickness.

RESULTS

Quadriceps echo intensity at discharge (81.3 ± 20.6 [a.u.]) was significantly lower than at admission (84.0 ± 20.5 [a.u.]). Protein intake at discharge (1.2 [1.0-1.4] g/kg/day) was significantly higher than at admission (1.2 [0.9-1.4] g/kg/day). Change in protein intake was negatively and significantly related to the change in quadriceps echo intensity. In contrast, change in protein intake was not independently and significantly related to change in quadriceps thickness.

CONCLUSIONS

Our results indicate that an increase in protein intake is related to a decrease in intramuscular adipose tissue of the quadriceps in older inpatients. Nutritional intervention for increasing protein intake in older inpatients may be essential for decreasing intramuscular adipose tissue of the quadriceps.

Relationship between physical activity levels and changes in skeletal muscle characteristics in patients with stroke

PURPOSE

This study aimed to investigate the relationship between physical activity (PA) levels and short-term changes in skeletal muscle characteristics in patients with subacute hemiparetic stroke.

MATERIALS AND METHODS

This prospective observational study included 76 patients with stroke who received inpatient care in a convalescent rehabilitation ward. The PA level was measured as the duration of daily total PA (≥ 1.5 metabolic equivalents) using a triaxial accelerometer for 7 days after admission. The outcomes were changes in the quadriceps muscle quality and quantity on the affected and unaffected sides, as assessed by ultrasonography at admission and 1 month after admission.

RESULTS

Multiple regression analysis indicated that the duration of total PA was significantly associated with a percentage change in quadriceps muscle quality (p = 0.011) and quantity (p = 0.012) on the affected side. However, no significant relationship was observed between the muscle quality and quantity on the unaffected side.

CONCLUSIONS

The results revealed that PA was associated with changes in the quadriceps muscle quality and quantity on the affected side in patients with subacute hemiparetic stroke. These findings highlight the importance of promoting PA in stroke rehabilitation to improve muscle properties and functional outcomes.

Effect of subcutaneous adipose tissue and muscle thicknesses on rectus femoris and vastus intermedius ultrasound echo intensities: a cadaver study

PURPOSE

The purpose of this study was to examine the effect of subcutaneous adipose tissue (SCAT) thickness and rectus femoris (RF) muscle thickness on RF and vastus intermedius (VI) echo intensity using human cadavers.

METHODS

The echo intensity of the RF and VI was measured in 11 legs of seven cadavers under three conditions: intact condition (Model 1), SCAT removed (Model 2), and SCAT and RF removed (Model 3).

RESULTS

RF echo intensity in Model 1 (69.2 ± 20.3 a.u.) was significantly lower than that in Model 2 (83.4 ± 15.9 a.u.) (P = 0.003). VI echo intensity in Models 1 to 3 showed similar results to RF echo intensity (P = 0.003 to 0.001). Regarding the relationship between VI echo intensity and VI muscle thickness, the regression lines shifted upward in a parallel fashion in the order Model 1, Model 2, and Model 3. Multiple regression analysis revealed that the variation in RF echo intensity was explained by RF muscle thickness (P = 0.036) and SCAT thickness (P = 0.001), while the variation in VI echo intensity was explained by RF muscle thickness (P = 0.035).

CONCLUSION

These results suggest that SCAT thickness and RF muscle thickness induce lower RF echo intensity, while RF muscle thickness induces lower VI echo intensity.

Greater intramuscular adipose tissue of the quadriceps in older inpatients at post-acute hospital admission is more strongly related to a low rate of home discharge than a loss of muscle mass

This study aimed to examine the relationships between intramuscular adipose tissue and muscle mass of the quadriceps at post-acute hospital admission and the low rate of home discharge. This prospective study included 389 inpatients aged ≥ 65 years. Patients were divided into two groups according to the destination: home discharge (n = 279) and no-home discharge (n = 110) groups. The primary outcome was hospital discharge destination (home discharge or not). Intramuscular adipose tissue and muscle mass of the quadriceps were assessed at post-acute hospital admission using echo intensity and muscle thickness on ultrasound images, respectively. Logistic regression analysis was used for determining whether quadriceps echo intensity is related to home discharge. Quadriceps echo intensity was significantly and independently associated with home discharge (odds ratio [per 1 SD increase] = 1.43, p = 0.045). Quadriceps thickness was not associated with home discharge (odds ratio [per 1 SD increase] = 1.00, p = 0.998). Our study indicates that greater intramuscular adipose tissue of the quadriceps in older inpatients at post-acute hospital admission is more strongly related to a low rate of home discharge than a loss of muscle mass.

Longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients at different activities of daily living levels

BACKGROUND & AIMS

Whether there is a longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps at different activities of daily living (ADL) levels remains unclear. This study aimed to examine the longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients at different ADL levels.

METHODS

This prospective cohort study was hospital-based and included 198 inpatients aged ≥65 years. Ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were assessed based on muscle thickness and echo intensity, respectively. The changes in quadriceps thickness and echo intensity were calculated by subtracting these baseline values from these values at discharge. ADL were assessed at admission using the Barthel Index (BI). The participants were divided into the low BI (BI score <60) and high BI (BI score ≥60) groups in accordance with the BI score. Multiple regression analysis was performed to examine whether the change in quadriceps echo intensity was independently and significantly related to change in quadriceps thickness, even after adjusting for confounding factors in the total participants and high and low BI groups.

RESULTS

The number of the high and low BI groups were 54 and 144. Change in quadriceps echo intensity was independently and significantly related to changes in quadriceps thickness of the total participants (β = -0.53, p < 0.01) and low BI (β = - 0.51, p < 0.01) and high BI (β = -0.70, p < 0.01) groups.

CONCLUSIONS

The results of this study indicate that there is a longitudinal negative relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients regardless of ADL level. Intramuscular adipose tissue may be an important contributing factor for muscle mass.

Muscular Echo-Intensity of the Quadriceps by Ultrasound Is More Related to Improvement of Gait Independence than Muscle Thickness in Older Inpatients

OBJECTIVES

This study aimed to examine whether the decrease in muscular echo-intensity of the quadriceps by ultrasound in older inpatients is related to the improvement of gait independence than the increase of muscle thickness.

DESIGN

Longitudinal study.

SETTING

Hospital-based study.

PARTICIPANTS

This study included 171 inpatients aged ≥ 65 years (median age: 84.0 [77.0-88.0], 56.1% female). Patients who were able to walk independently at hospital admission were excluded from the study.

MEASUREMENTS

Improvement of gait independence during hospital stay was assessed using the change in Functional Independence Measure (FIM) gait score (i.e., FIM gait score at hospital discharge minus FIM gait score at hospital admission) and FIM gait score at hospital discharge. Muscular echo-intensity and muscle thickness of the quadriceps were assessed at hospital admission and discharge using ultrasound images, respectively. Muscular echo-intensity has been shown to be mainly related to intramuscular adipose tissue. Multiple linear regression analysis was performed to identify the factors independently associated with the change in FIM gait score and FIM gait score at discharge.

RESULTS

Change in quadriceps echo-intensity was independently and significantly associated with the change in FIM gait score (β = -0.22, p = 0.017) and FIM gait score at hospital discharge (β = -0.21, p = 0.017). In contrast, change in quadriceps thickness was not independently and significantly associated with the change in FIM gait score (β = 0.16, p = 0.050) and FIM gait score at hospital discharge (β = 0.15, p = 0.050).

CONCLUSIONS

Our study indicates that a decrease in muscular echo-intensity of the quadriceps by ultrasound is more related to the improvement of gait independence than an increase of muscle thickness in older inpatients. Intervention for intramuscular adipose tissue of the quadriceps may be important for improving gait independence in older inpatients.

The degree of recovery in swallowing ability in older inpatients with aspiration pneumonia is related to intramuscular adipose tissue of the quadriceps than to muscle mass

BACKGROUND & AIM

A recent study reported that the increase in intramuscular adipose tissue of the quadriceps in older inpatients is related to a decreasing degree of recovery in swallowing ability compared to the loss of muscle mass. However, whether the association remains true in case of aspiration pneumonia is unclear. Therefore, this study aimed to examine the relationship between the degree of recovery in swallowing ability and intramuscular adipose tissue in the quadriceps of older inpatients with aspiration pneumonia.

METHODS

This prospective study included 39 older patients with aspiration pneumonia. Swallowing ability was assessed using the Food Intake Level Scale (FILS). The indicators for the degree of recovery in swallowing ability were FILS at discharge and change in FILS. A greater change in FILS indicates a greater improvement in swallowing ability. Intramuscular adipose tissue and muscle mass of the quadriceps were evaluated at admission using echo intensity and muscle thickness on ultrasound images, respectively. Multiple regression analysis was used to determine whether the echo intensity of the quadriceps was independently and significantly related to FILS at discharge and the change in FILS. Independent variables were age, sex, days from disease onset, echo intensity and muscle thickness of the quadriceps, subcutaneous fat thickness of the thigh, FILS at admission, and number of units of rehabilitation therapy.

RESULTS

Echo intensity of the quadriceps (β = -0.363, p = 0.012) and FILS at admission (β = 0.556, p < 0.001) were independently and significantly associated with FILS at discharge (R2 = 0.760, f2 = 3.167, statistical power = 1.000). Similar variables (echo intensity of the quadriceps [β = -0.498, p = 0.012] and FILS at admission [β = -0.635, p < 0.001]) were independently and significantly related to change in FILS (R2 = 0.547, f2 = 1.208, statistical power = 0.998). Quadriceps muscle thickness was not independently and significantly related to FILS at discharge and change in FILS.

CONCLUSION

Our results indicate that intramuscular adipose tissue of the quadriceps in older inpatients with aspiration pneumonia is more strongly related to the degree of recovery in swallowing ability (that is, swallowing ability at discharge and change in swallowing ability) than muscle mass, and patients who have high intramuscular adipose tissue of the quadriceps at admission have a lower degree of recovery in swallowing ability.

Higher malnutrition risk in older inpatients who are referred to the department of rehabilitation is related to increase of intramuscular adipose tissue: A prospective study

BACKGROUND & AIMS

A recent cross-sectional study reported that a higher intramuscular adipose tissue of the quadriceps is related to higher malnutrition risk in older inpatients. However, a longitudinal relationship between them in older inpatients remains unclear. This study aimed to examine the relationship between the malnutrition risk at hospital admission and change in quadriceps intramuscular adipose tissue induced during the hospital stay in older inpatients.

METHODS

The inclusion criteria in this longitudinal study were older patients (aged ≥65 years) who were referred to the department of rehabilitation. Patients who died during a hospital stay, who underwent thigh amputation, and who had a hospital stay of <3 days or a lack of data were excluded from the study. Malnutrition risk at post-acute hospital admission was assessed using Geriatric Nutritional Risk Index (GNRI). Intramuscular adipose tissue and muscle mass of the quadriceps were assessed at hospital admission and discharge using echo intensity and muscle thickness on ultrasound images. The changes in quadriceps echo intensity and thickness were calculated by subtracting these baseline values from these values at discharge. Multiple regression analysis was performed to examine whether GNRI at admission is independently and significantly related to the quadriceps echo intensity and thickness at discharge and changes in quadriceps echo intensity and thickness. The independent variables were GNRI, age, sex, days from onset disease, disease, quadriceps echo intensity or thickness at admission, and change in quadriceps thickness.

RESULTS

This study included 200 inpatients (median [interquartile range] age: 83.0 [77.0-88.0], 57.0% female). GNRI at admission was significantly and independently related to quadriceps echo intensity at discharge (β = -0.136, p = 0.008) and change in quadriceps echo intensity (β = -0.177, p = 0.008). In contrast, GNRI was not significantly and independently related to quadriceps thickness at discharge (β = 0.087, p = 0.158) and change in quadriceps thickness (β = 0.133, p = 0.158).

CONCLUSIONS

Our results suggest that a higher malnutrition risk at post-acute hospital admission in older inpatients is related to an increase of intramuscular adipose tissue of the quadriceps during the hospital stay. Malnutrition risk at hospital admission in older inpatients is considered to be a predictor for an increase of intramuscular adipose tissue of the quadriceps during a hospital stay.

Utility of ultrasound as a promising diagnostic tool for stroke-related sarcopenia: A retrospective pilot study

Stroke patients undergo extensive changes in muscle mass which lead to stroke-related sarcopenia. Stroke-related sarcopenia has a significant impact on the functional outcome of stroke survivors. So, it is important to measure muscle mass in stroke patients. This study aimed to examine the correlation between ultrasonographic quadriceps muscle thickness (QMT) and dual-energy X-ray absorptiometry (DXA) derived appendicular lean mass (ALM) in patients with acute hemiplegic stroke. Twenty five participants were included (13 men and 12 women) in this study, who were diagnosed with stroke within 1 month. For both paretic and non-paretic legs, QMT was measured by an ultrasound and ALM was obtained by performing DXA scan. We analyzed the difference and the correlation between ultrasonographic QMT and DXA-derived lean body mass of both paretic and non-paretic legs. Stroke patients were divided into 2 groups according to the paretic knee extensor power. Ultrasonographic QMT, DXA scan findings, and functional parameters were compared. There was a significant correlation between QMT and ALM index, and between QMT and site-specific lean mass (SSLM) of both the legs for both the sexes (P < .05). In multivariate linear regression model, we made adjustments for the confounding factors of age, sex, body mass index (BMI) and paretic knee extensor power. We observed a positive relationship between QMT and ALM index (P < .05), and between QMT and SSLM of both the legs (P < .05). The % QMT showed higher difference than % SSLM between paretic and non-paretic legs (10.25% vs 4.58%). The QMT measurements of ultrasound show a great relationship with DXA scan findings. Ultrasound better reflects the change of muscle mass between paretic and non-paretic legs than DXA scan at an acute phase of stroke. Ultrasound could be a useful tool to evaluate stroke-related sarcopenia.

Nutritional and swallowing statuses but not intramuscular adipose tissue and muscle mass are related to activities of daily living in older inpatients who are judged as severely low body mass index in the Global Leadership Initiative on Malnutrition criteria

BACKGROUND & AIMS

Which factors are related to activities of daily living (ADL) in older inpatients who are judged as the severely low body mass index (BMI) in the Global Leadership Initiative on Malnutrition (GLIM) criteria is unclear. This study aimed to examine the related factors to ADL in older inpatients who are judged as severely low BMI in the GLIM criteria.

METHODS

This cross-sectional study included 377 inpatients aged ≥70 years. We divided the participants into the following three groups: the severely low BMI group (<17.8 kg/m²) (n = 106), moderately low BMI group (≥17.8 to < 20.0 kg/m²) (n = 87), and normal BMI group (≥20.0 kg/m²) (n = 184). ADL were assessed using the motor-Functional Independence Measure (FIM). Multiple regression analyses were used to identify the factors independently associated with the motor-FIM score in each group.

RESULTS

The Food Intake Level Scale (FILS) and Geriatric Nutritional Risk Index (GNRI) were significantly related to the motor-FIM score of the severely low BMI group. The FILS, GNRI, updated Charlson comorbidity index (UCCI), and quadriceps echo intensity were significantly related to the motor-FIM score of the moderately low BMI group. The FILS, GNRI, UCCI, quadriceps thickness, and subcutaneous fat thickness of the thigh were significantly related to the motor-FIM score of the normal BMI group.

CONCLUSIONS

Our findings indicate that nutritional and swallowing statuses but not intramuscular adipose tissue and muscle mass are related to ADL in older inpatients who are judged as severely low BMI in the GLIM criteria. Intervention for nutritional and swallowing statuses may be prioritized over an exercise intervention to improve ADL of older inpatients who are judged as severely low BMI.

Relationship between muscle mass and fraction of intramuscular adipose tissue of the quadriceps in older inpatients

BACKGROUND

In 2021, the International Society of Physical and Rehabilitation Medicine (ISPRM) special interest group on sarcopenia included the quadriceps thickness assessed with ultrasound image as an indicator of muscle mass in the diagnosis criteria of sarcopenia. If quadriceps echo intensity of older inpatients is to be a strong predictor of quadriceps thickness, muscle quality of the quadriceps may be estimated by the muscle mass when diagnosing sarcopenia using the criteria of ISPRM.

OBJECTIVE

This study aimed to examine the association between muscle mass and fraction of intramuscular adipose tissue of the quadriceps in older inpatients.

METHODS

This cross-sectional study included 399 inpatients aged ≥ 65 years. Primary outcomes were muscle mass and fraction of intramuscular adipose tissue of the quadriceps. Images were acquired using a B-mode ultrasound. Muscle mass and fraction of intramuscular adipose tissue of the quadriceps were assessed based on the muscle thickness and echo intensity, respectively. A multiple regression analysis (forced entry method) was performed to confirm whether quadriceps echo intensity was related to quadriceps thickness even after adjusting for other factors.

RESULTS

In the multiple regression analyses for both male and female models, quadriceps echo intensity (male: β = - 0.537, p < 0.001; female: β = - 0.438, p < 0.001), Geriatric Nutritional Risk Index (male: β = 0.236, p < 0.001; female: β = 0.213, p < 0.001), and subcutaneous fat thickness of the thigh (male: β = 0.197, p < 0.001; female: β = 0.248, p < 0.001) were independently and significantly associated with quadriceps thickness.

CONCLUSIONS

Our results show that there is a negative and significant association between muscle mass and fraction of intramuscular adipose tissue in older inpatients. Muscle quality of the quadriceps in older inpatients may be estimated to some extent by the muscle mass.

Changes in Muscle Thickness and Echo Intensity in Chronic Stroke Survivors: A 2-Year Longitudinal Study

Background and Purpose

The objective of this study was to identify 2-year longitudinal changes in the muscle thickness (MT) and echo intensity (EI) of the abdominal, thigh, and lower limb muscles in chronic stroke survivors.

Methods

This study included 15 chronic stroke survivors aged 74.1±9.9 years. The MT, EI, and subcutaneous fat thickness values of the following muscles on the paretic and nonparetic sides were assessed on transverse ultrasound images: rectus abdominis, external oblique, internal oblique, transversus abdominis, rectus femoris (RF), vastus intermedius, vastus lateralis (VL), vastus medialis, tibialis anterior, gastrocnemius, and soleus. The ultrasound measurements were performed both at baseline and 2 years later.

Results

After 2 years, the VL on the paretic side showed a significant decrease in MT (p=0.031) and increase in EI (p=0.002), whereas the RF on the nonparetic side showed a significant decrease in EI (p=0.046). Correlation coefficient analyses showed that changes in MT (r=0.668, p=0.012) and EI (r=0.597, p=0.018) of the VL on the paretic side were significantly associated with a change in the body mass index.

Conclusions

The findings of this longitudinal study suggest that the VL on the paretic side is subject to deteriorations in muscle quantity and quality, and conversely that the RF on the nonparetic side shows an improvement in muscle quality after 2 years in chronic stroke survivors.

Muscle Electrical Impedance Properties and Activation Alteration After Functional Electrical Stimulation-Assisted Cycling Training for Chronic Stroke Survivors: A Longitudinal Pilot Study

Electrical impedance myography (EIM) is a sensitive assessment for neuromuscular diseases to detect muscle inherent properties, whereas surface electromyography (sEMG) is a common technique for monitoring muscle activation. However, the application of EIM in detecting training effects on stroke survivors is relatively few. This study aimed to evaluate the muscle inherent properties and muscle activation alteration after functional electrical stimulation (FES)-assisted cycling training to chronic stroke survivors. Fifteen people with chronic stroke were recruited for 20 sessions of FES-assisted cycling training (40 min/session, 3–5 sessions/week). The periodically stimulated and assessed muscle groups were quadriceps (QC), tibialis anterior (TA), hamstrings (HS), and medial head of gastrocnemius (MG) on the paretic lower extremity. EIM parameters [resistance (R), reactance (X), phase angle (θ), and anisotropy ratio (AR)], clinical scales (Fugl-Meyer Lower Extremity (FMA-LE), Berg Balance Scale (BBS), and 6-min walking test (6MWT)] and sEMG parameters [including root-mean square (RMS) and co-contraction index (CI) value] were collected and computed before and after the training. Linear correlation analysis was conducted between EIM and clinical scales as well as between sEMG and clinical scales. The results showed that motor function of the lower extremity, balance, and walking performance of subjects improved after the training. After training, θ value of TA (P = 0.014) and MG (P = 0.017) significantly increased, and AR of X (P = 0.004) value and AR of θ value (P = 0.041) significantly increased on TA. The RMS value of TA decreased (P = 0.022) and a significant reduction of CI was revealed on TA/MG muscle pair (P < 0.001). Significant correlation was found between EIM and clinical assessments (AR of X value of TA and FMA-LE: r = 0.54, P = 0.046; X value of TA and BBS score: 0.628, P = 0.016), and between sEMG and clinical scores (RMS of TA and BBS score: r = −0.582, P = 0.029). This study demonstrated that FES-assisted cycling training improved lower limb function by developing coordinated muscle activation and facilitating an orderly myofiber arrangement. The current study also indicated that EIM can jointly evaluate lower extremity function alteration with sEMG after rehabilitation training.

Clinical Trail Registration: The study was registered on the Clinical Trial Registry (trial registration number: NCT 03208439, https://clinicaltrials.gov/ct2/show/NCT03208439).

Higher Body Mass Index in Hospitalized Older Patients Is Related to Higher Muscle Quality

OBJECTIVES

This study aimed to examine the relationship between muscle mass, intramuscular adipose tissue, and body mass index (BMI) in older inpatients.

DESIGN

Cross-sectional study.

SETTING

Hospital-based study.

PARTICIPANTS

This study included 413 inpatients aged ≥ 65 years (186 men and 227 women).

MEASUREMENTS

Muscle mass and intramuscular adipose tissue of the quadriceps were assessed by measuring the muscle thickness and echo intensity on ultrasound images. To examine the relationship between quadriceps thickness and echo intensity and BMI in total participants and each sex, the Kendall rank correlation coefficient was used. Multiple regression analysis was performed to examine whether BMI was independently and significantly related to the quadriceps thickness and echo intensity, even after adjusting for other variables for total participants and each sex. The independent variables in multiple regression analyses were BMI, age, disease, days from onset disease.

RESULTS

The results of the correlation analyses showed that BMI was significantly related to the quadriceps thickness (total participants, τ = 0.431; men, τ = 0.491; women, τ = 0.388) and echo intensity (total participants, τ = -0.239; men, τ = -0.318; women, τ = -0.188). In the multiple regression analysis, BMI was independently and significantly associated with the quadriceps thickness (total participants, β = 0.535; men, β = 0.548; women, β = 0.519) and echo intensity (total participants, β = -0.287; men, β = -0.398; women, β = -0.210).

CONCLUSION

This study indicated that older inpatients with a higher BMI have greater muscle mass and less intramuscular adipose tissue of the quadriceps. These results suggested that a higher BMI in older inpatients is related to higher quadriceps muscle quality.

Longitudinal relationship between intramuscular adipose tissue of the quadriceps and activities of daily living in older inpatients

BACKGROUND

The longitudinal relationship between intramuscular adipose tissue of the quadriceps and activities of daily living (ADL) in older inpatients remains unclear. This study aimed to examine whether decrease of intramuscular adipose tissue of the quadriceps in older inpatients is related to the recovery of ADL than increase of muscle mass.

METHODS

This longitudinal study included 202 inpatients aged ≥65 years [median age: 83.0 (77.0-88.0), 56.4% female]. Recovery of ADL during hospital stay was assessed using the change in Barthel index (BI) score (i.e. BI score at discharge minus BI score at admission) and BI score at discharge. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed using echo intensity and muscle thickness on ultrasound images, respectively. Higher echo intensity indicates greater intramuscular adipose tissue. Multiple regression analysis was performed to identify the factors independently associated with the change in BI score and BI score at discharge. Changes in quadriceps echo intensity and thickness and subcutaneous fat thickness of the thigh, quadriceps echo intensity and thickness, and subcutaneous fat thickness of the thigh at admission, age, sex, days from onset disease, BI score at admission, and disease were set as independent variables.

RESULTS

The means of the change in quadriceps echo intensity and thickness were -2.3 ± 15.7 and 0.1 ± 0.4 cm, respectively. The median of the change in BI score was 15.0 (0.0-30.0). The quadriceps echo intensity at discharge was significantly lower than at admission (P = 0.043). The quadriceps thickness (P = 0.004) and BI score at discharge (P < 0.001) were significantly higher than those at admission. Change in quadriceps echo intensity was independently and significantly associated with the change in BI score (β = -0.25, P = 0.006) and BI score at discharge (β = -0.18, P = 0.006). In contrast, change in quadriceps thickness was not independently and significantly associated with the change in BI score (β = 0.09, P = 0.244) and BI score at discharge (β = 0.06, P = 0.244).

CONCLUSIONS

Our study indicates that a decrease of intramuscular adipose tissue of the quadriceps is related to the recovery of ADL than an increase of muscle mass in older inpatients. Intramuscular adipose tissue of the quadriceps in older inpatients is considered to be a predictor for the recovery of ADL, and intervening for intramuscular adipose tissue may be important for improving ADL in older inpatients.

Physique, range of motion, and gross muscle strength in hemiplegic para swimmers: a cross-sectional case series

[Purpose] The physical functions related to swimming should be evaluated to enhance competitive performance and prevent sports injuries. This study aimed to determine the physique, range of motion, and gross muscle strength of the limbs among hemiplegic para swimmers. [Participants and Methods] Three male para swimmers with hemiplegia and five male para swimmers with impaired vision were included in the study. The limb circumference, range of motion, quadriceps flexibility, and gross muscle strength were evaluated. The hemiplegic swimmers and swimmers with impaired vision were compared using an unpaired t-test. [Results] The maximum values of the upper and forearm circumferences; the range of motion for shoulder flexion, external rotation, ankle dorsiflexion on the paretic side; and the single-leg sit-to-stand test of the dominant limb were significantly lower in hemiplegic swimmers than in swimmers with impaired vision. [Conclusion] Hemiplegic swimmers had decreased upper limb circumferences on the paretic limb; the range of motion for shoulder flexion, external rotation, and ankle dorsiflexion on the paretic limb; and muscle strength on the dominant lower limb.

The Effect of Repetitive Transcranial Magnetic Stimulation on Lower-Limb Motor Ability in Stroke Patients: A Systematic Review

Repetitive transcranial magnetic stimulation (rTMS) is fundamental in inducing neuroplastic changes and promoting brain function restoration. Nevertheless, evidence based on the systematic assessment of the implication of rTMS in stroke patients is inadequate. This study aimed to evaluate the value of rTMS in the treatment of lower-limb motor dysfunction in stroke patients via gait characteristics. The electronic literature search was performed in ScienceDirect, Google Scholar, and PubMed databases using "repetitive transcranial magnetic stimulation," "gait," and "stroke" between 2000 and 2020. By screening all the identified studies, a total of 10 studies covering 257 stroke patients were included by matching the inclusion criteria, involving both rTMS with high (≥5 Hz) and low frequency (<5 Hz). Despite the limited study number and relatively high risk of bias, the results of this review primarily confirmed the enhancing effects of rTMS on the lower-limb motor ability (e.g., gait and balance) of stroke patients. In addition, 15- to 20-min course of rTMS for 2 to 3 weeks was found to be the most common setting, and 1 Hz and 10 Hz were the most commonly used low and high frequencies, respectively. These results might have significant clinical applications for patients with weakened lower-limb mobility after a stroke. Nevertheless, more rigorous studies in this field are much warranted. Systematic Review Registration:https://inplasy.com/, identifier INPLASY202180079.

Intramuscular adipose tissue in the quadriceps is more strongly related to recovery of activities of daily living than muscle mass in older inpatients

BACKGROUND

The relationship between intramuscular adipose tissue at admission and recovery of activities of daily living (ADL) remains unclear. This study aimed to examine the relationship between intramuscular adipose tissue in the quadriceps at admission and recovery of ADL in older inpatients.

METHODS

This prospective study included 404 inpatients aged ≥65 years (54.7% female). Recovery of ADL during hospital stay was assessed using the Barthel Index (BI) score at discharge, BI score change, and BI efficiency. Higher BI at discharge, BI score change, and BI efficiency indicate more improvement in ADL. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed using echo intensity and muscle thickness on ultrasound images, respectively. Multiple regression analysis was performed to identify factors independently associated with BI score at discharge, BI score change, and BI efficiency. The independent variables were BI score at admission, echo intensity and muscle thickness of the quadriceps, age, sex, number of medications, C-reactive protein concentration, updated Charlson Comorbidity Index score, Food Intake Level Scale, Geriatric Nutritional Risk Index score, days from onset disease, length of hospital stay, number of units of rehabilitation therapy, and subcutaneous fat thickness of the thigh.

RESULTS

The medians (inter-quartile range) of the BI score at discharge, BI score change, and BI efficiency were 60.0 (35.0-80.0), 10.0 (0.0-25.0), and 0.11 (0.00-0.37), respectively. The median (inter-quartile range) of the length of hospital stay (days) and days from onset disease were 58.0 (39.0-92.0) and 79.0 (49.0-112.0), respectively. Quadriceps echo intensity was independently and significantly associated with the BI score at discharge (β = -0.13, P < 0.01), BI score change (β = -0.23, P < 0.01), and BI efficiency (β = -0.21, P < 0.01). Quadriceps thickness was not independently and significantly associated with the BI score at discharge (β = -0.02, P = 0.68), BI score change (β = -0.02, P = 0.79), and BI efficiency (β = 0.03, P = 0.67).

CONCLUSIONS

Our study indicates that greater intramuscular adipose tissue in the quadriceps at admission is more strongly related to worse recovery of ADL than less muscle mass in older inpatients. Greater intramuscular adipose tissue in the quadriceps in older inpatients is considered to be a predictor of worse recovery of ADL, and intervening for greater intramuscular adipose tissue may be important for improving ADL in older inpatients.

Intramuscular adipose tissue of the quadriceps is more strongly related to recovery of swallowing ability than is muscle mass in older inpatients: A prospective study

OBJECTIVES

This study aimed to examine whether intramuscular adipose tissue of the quadriceps at admission is related to the recovery of swallowing ability during a hospital stay in older inpatients.

METHODS

This prospective study included 344 inpatients ages ≥ 65 y. Those who had stroke that was the obvious cause of dysphagia were excluded. Recovery of swallowing ability was assessed using Food Intake Level Scale (FILS) score at discharge and FILS change. Ultrasound images were acquired at admission. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed based on echo intensity and muscle thickness, respectively. Multiple regression analysis was performed to examine whether quadriceps echo intensity is independently associated with FILS score at discharge and FILS change. The independent variables were quadriceps echo intensity and thickness, subcutaneous fat thickness of the thigh, Barthel Index score at admission, age, sex, number of medications, C-reactive protein, updated Charlson Comorbidity Index, FILS score at admission, Geriatric Nutritional Risk Index, days from disease onset, length of hospital stay, and units of rehabilitation therapy.

RESULTS

Quadriceps echo intensity was independently and significantly associated with FILS score at discharge (β = -0.15, P < 0.01) and FILS change (β = -0.19, P < 0.01). Quadriceps thickness was not independently and significantly associated with FILS score at discharge or FILS change.

CONCLUSIONS

The present study revealed that intramuscular adipose tissue of the quadriceps in older inpatients is more strongly related to recovery of swallowing ability than is muscle mass.

Greater Quadriceps Muscle Mass at Post-Acute Care Admission is Associated with Better Swallowing Ability at Discharge among Adults with Stroke

OBJECTIVES

This study aimed to examine the relationship between muscle mass and intramuscular adipose tissue of the quadriceps at post-acute care admission and recovery of swallowing ability in patients with stroke.

DESIGN

Prospective study.

SETTING AND PARTICIPANTS

This study was hospital-based and included 62 inpatients with stroke.

METHODS

The primary outcome was swallowing ability at discharge. The swallowing ability was assessed using the Food Intake Level Scale (FILS). The FILS change was calculated by subtracting FILS at admission from FILS at discharge. Ultrasound images were acquired at admission using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were assessed based on muscle thickness and echo intensity, respectively. The mean muscle thickness and echo intensity of the right and left quadriceps were used in the analysis. A multiple regression analysis was performed to identify the factors independently associated with the FILS at discharge and FILS change. The independent variables were the muscle thickness and echo intensity of the quadriceps, FILS at admission, age, sex, body mass index, days from stroke onset, C-reactive protein, updated Charlson comorbidity index, number of medications, unit number of rehabilitation therapy, and Barthel Index score at admission.

RESULTS

Muscle thickness of the quadriceps was significantly and independently associated with FILS at discharge (β = 0.27) and FILS change (β = 0.40). Echo intensity of the quadriceps was not significantly and independently associated with FILS at discharge (β = 0.22) and FILS change (β = 0.31).

CONCLUSIONS AND IMPLICATIONS

Our results indicated that greater quadriceps muscle mass at post-acute care admission was associated with better swallowing ability at discharge in patients with stroke. Assessing muscle mass of the quadriceps at admission is important for predicting recovery of swallowing ability and interventions for quadriceps muscle mass may be effective for improving swallowing ability of patients with stroke.

Increased intramuscular adipose tissue of the quadriceps is related to decreased activities of daily living in patients who have had a stroke

OBJECTIVE

This study examined the relationships between intramuscular adipose tissue of the quadriceps on the paretic and non-paretic sides at admission and activities of daily living (ADL) at discharge in patients who had a stroke.

METHODS

This prospective cohort study included 44 stroke inpatients. ADL were assessed at discharge using the Barthel index (BI) score. Ultrasound images were acquired at admission using B-mode ultrasound imaging. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed based on echo intensity and muscle thickness, respectively. Relationships between BI score at discharge and quadriceps echo intensity or thickness on the paretic and non-paretic sides were assessed using partial correlation coefficients. Age, sex, days from onset of stroke, Fugl-Meyer assessment lower extremity score, and subcutaneous fat thickness of the thigh were used as the control variables in the partial correlation analysis.

RESULTS

BI score at discharge was significantly related to quadriceps echo intensity on the paretic (partial correlation coefficient = -0.377, P = 0.018) and non-paretic (partial correlation coefficient = -0.364, P = 0.023) sides. By contrast, quadriceps thickness on the paretic (partial correlation coefficient = 0.284, P = 0.075) and non-paretic (partial correlation coefficient = 0.278, P = 0.083) sides were not significantly related to BI score at discharge.

CONCLUSIONS

The present study revealed the negative relationship between intramuscular adipose tissue of the quadriceps on the paretic and non-paretic sides at admission and ADL at discharge. Assessments and interventions of intramuscular adipose tissue in the quadriceps may be essential for predicting and improving ADL of patients who have had a stroke.

Application of ultrasound for muscle assessment in sarcopenia: 2020 SARCUS update

PURPOSE

In 2018, the SARCUS working group published a first article on the standardization of the use of ultrasound to assess muscle. Recommendations were made for patient positioning, system settings and components to be measured. Also, shortcomings in knowledge were mentioned. An important issue that still required standardization was the definition of anatomical landmarks for many muscles.

METHODS

A systematic search was performed in Medline, SCOPUS and Web of Sciences looking for all articles describing the use of ultrasound in the assessment of muscle not described in the first recommendations, published from 01/01/2018 until 31/01/2020. All relevant terms used for older people, ultrasound and muscles were used.

RESULTS

For 39 muscles, different approaches for ultrasound assessment were found that likely impact the values measured. Standardized anatomical landmarks and measuring points were proposed for all muscles/muscle groups. Besides the five already known muscle parameters (muscle thickness, cross-section area, pennation angle, fascicle length and echo-intensity), four new parameters are discussed (muscle volume, stiffness, contraction potential and microcirculation). The former SARCUS article recommendations are updated with this new information that includes new muscle groups.

CONCLUSIONS

The emerging field of ultrasound assessment of muscle mass only highlights the need for a standardization of measurement technique. In this article, guidelines are updated and broadened to provide standardization instructions for a large number of muscles.

Muscle and tendon properties of the spastic lower leg after stroke defined by ultrasonography: a systematic review

INTRODUCTION

Peripheral muscle and tendon changes after stroke can influence the functional outcome of patients. The aim of this systematic review was to summarize the evidence of ultrasonographic changes in morphological muscle and tendon properties of the spastic hemiparetic lower leg in patients with first ever stroke.

EVIDENCE ACQUISITION

A systematic search was conducted through PubMed, Embase, Scopus, Cinahl, Cochrane Library, and manual searches from inception until May 1, 2020. Observational case control or cohort studies were included. Risk of bias was evaluated by using the Newcastle-Ottawa Quality Assessment Scale. Outcome parameters of interest included muscle thickness, muscle and tendon length, fascicle length, pennation angle and echo-intensity.

EVIDENCE SYNTHESIS

Nine studies investigated outcome parameters beyond one-month after stroke. We are unable to make a comprehensive statement. Nevertheless, there are some arguments for reduced muscle thickness and reduced fascicle length of the hemiplegic, spastic leg.

CONCLUSIONS

Despite the fact that objective assessment by ultrasonography holds promise for diagnosis and follow-up of spastic hemiparesis after stroke, more evidence is needed to determine how changes in morphological muscle and tendon properties are related to muscle weakness, severity of spasticity and compensation strategies such as disuse or overuse in longitudinal studies starting early after stroke.

Global DNA methylation pattern involved in the modulation of differentiation potential of adipogenic and myogenic precursors in skeletal muscle of pigs

Background

Skeletal muscle is a complex and heterogeneous tissue accounting for approximately 40% of body weight. Excessive ectopic lipid accumulation in the muscle fascicle would undermine the integrity of skeletal muscle in humans but endow muscle with marbling-related characteristics in farm animals. Therefore, the balance of myogenesis and adipogenesis is of great significance for skeletal muscle homeostasis. Significant DNA methylation occurs during myogenesis and adipogenesis; however, DNA methylation pattern of myogenic and adipogenic precursors derived from skeletal muscle remains unknown yet.

Methods

In this study, reduced representation bisulfite sequencing was performed to analyze genome-wide DNA methylation of adipogenic and myogenic precursors derived from the skeletal muscle of neonatal pigs. Integrated analysis of DNA methylation and transcription profiles was further conducted. Based on the results of pathway enrichment analysis, myogenic precursors were transfected with CACNA2D2-overexpression plasmids to explore the function of CACNA2D2 in myogenic differentiation.

Results

As a result, 11,361 differentially methylated regions mainly located in intergenic region and introns were identified. Furthermore, 153 genes with different DNA methylation and gene expression level between adipogenic and myogenic precursors were characterized. Subsequently, pathway enrichment analysis revealed that DNA methylation programing was involved in the regulation of adipogenic and myogenic differentiation potential through mediating the crosstalk among pathways including focal adhesion, regulation of actin cytoskeleton, MAPK signaling pathway, and calcium signaling pathway. In particular, we characterized a new role of CACNA2D2 in inhibiting myogenic differentiation by suppressing JNK/MAPK signaling pathway.

Conclusions

This study depicted a comprehensive landmark of DNA methylome of skeletal muscle-derived myogenic and adipogenic precursors, highlighted the critical role of CACNA2D2 in regulating myogenic differentiation, and illustrated the possible regulatory ways of DNA methylation on cell fate commitment and skeletal muscle homeostasis.

Supplementary information

The online version contains supplementary material available at 10.1186/s13287-020-02053-3.

Relationship Between Aging and Intramuscular Adipose Tissue in Older Inpatients

OBJECTIVE

Although older inpatients are known to develop various conditions, whether aging affects intramuscular adipose tissue in older inpatients remains unclear. In particular, an increase in intramuscular adipose tissue in persons aged ≥85 years has previously not been revealed in either older inpatients or community-dwelling older individuals. This study therefore aimed to examine whether aging affects intramuscular adipose tissue in older inpatients.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

This study was clinical-based and included 404 inpatients aged ≥65 years.

METHODS

We divided the participants into the following age groups: 65-74 years (n = 63), 75-84 years (n = 171), and ≥85 years (n = 170). B-mode ultrasound imaging was performed, and the intramuscular adipose tissue of the quadriceps was assessed based on echo intensity. One-way analysis of variance and analysis of covariance were used to compare the echo intensity of the quadriceps between the 65-74-year, 75-84-year, and ≥85-year groups.

RESULTS

The median (25th-75th percentile) ages of the 65-74-year group, 75-84-year group, and ≥85-year group were 70.0 (68.0-73.0), 80.0 (77.0-82.0), and 89.0 (87.0-91.0), respectively. In the one-way analysis of variance, the quadriceps echo intensity of the ≥85-year group was significantly higher than that of the 65-74-year and 75-84-year groups. In addition, the ≥85-year group had significantly higher quadriceps echo intensity than the 65-74-year group, even after adjusting for other confounding factors.

CONCLUSIONS AND IMPLICATIONS

The current study revealed that intramuscular adipose tissue in older inpatients increases with age, and the levels of intramuscular adipose tissue of older inpatients aged ≥85 years is higher than those of older inpatients aged 65-74 years.

Using GLIM criteria, cutoff value for low BMI in Asian populations discriminates high or low muscle mass: A cross-sectional study

OBJECTIVES

The aim of this study was to examine whether differences in muscle mass and intramuscular adipose tissue are present between patients with a moderately and severely low body mass index (BMI) as discriminated by the cutoff value for a low BMI among patients ≥70 y of age in Asian populations according to the Global Leadership Initiative on Malnutrition (GLIM) criteria.

METHODS

This cross-sectional study included 345 inpatients ≥70 y of age. The participants were placed into one of the following three groups: severely low BMI (<17.8 kg/m²; n = 96), moderately low BMI (≥17.8 to <20 kg/m²; n = 81), and normal BMI (≥20 kg/m²; n = 168). Ultrasound images were obtained with B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were assessed based on the muscle thickness and echo intensity, respectively. Analysis of covariance was used to examine the differences in the quadriceps thickness and echo intensity among the three groups.

RESULTS

The quadriceps thickness and echo intensity in the severely low, moderately low, and normal BMI groups were 0.9 ± 0.3, 1.1 ± 0.4, and 1.4 ± 0.5 cm and 93.3 ± 20.8, 91.3 ± 19.3, 80.1 ± 21.6, respectively. The quadriceps thickness in the severely low BMI group was statistically significantly lower than that in the moderately low BMI (P < 0.001) and normal BMI (P < 0.001) groups, and the quadriceps thickness in the moderately low BMI group was also statistically significantly lower than that in the normal BMI group (P < 0.001). The quadriceps echo intensity showed no significant differences among the three groups.

CONCLUSIONS

The cutoff value for a low BMI discriminates high or low muscle mass. Results of this study supported the validity of 17.8 kg/m² as the cutoff value for a low BMI with which to grade the severity of malnutrition in Asian populations ≥70 y of age according to the GLIM criteria from the perspective of muscle mass.

Intramuscular Fat in the Medial Gastrocnemius Muscle of People Who Have Had a Stroke

Objective: To compare intramuscular fat fraction in people who have ankle contractures following stroke with the intramuscular fat fraction in control participants.

Design: mDixon MRI images were used to quantify intramuscular fat fractions in the medial gastrocnemius muscles of people who had experienced a hemiparetic stroke (n = 14, mean age 60 ± 13 years) and control participants (n = 18, mean age 66 ± 12 years).

Results: Intramuscular fat fractions were similar in the paretic and non-paretic sides of stroke patients (mean on paretic side 14.5%, non-paretic side 12.8%, difference 1.6%, 95% confidence interval −0.7 to 4.1%). The intramuscular fat fraction on the paretic side was higher than in the control group (mean intramuscular fat fraction in control muscles 7.6%; difference 7.8%, 95% confidence interval 4.6–10.9%). The difference between intramuscular fat fractions in non-paretic and control legs increased with age. Body mass index was similar in stroke patients and controls. There was no association between medial gastrocnemius intramuscular fat fraction and dorsiflexion range.

Conclusion: Muscles of stroke patients had elevated intramuscular fat fractions compared to muscles from control participants which were not explained by differences in body mass index. There is no clear relationship between intramuscular fat in the medial gastrocnemius muscle and dorsiflexion range of motion.

Quadriceps Thickness and Echo Intensity Predict Gait Independence in Individuals with Severe and Mild Hemiparetic Stroke

INTRODUCTION

Smaller muscle size and higher adipose tissue ratio of the quadriceps femoris are often observed after stroke. However, it is unclear whether muscle size and the intramuscular fat ratio of the quadriceps measured with ultrasonography (US) reflect gait independence in individuals with mild or severe hemiparetic stroke.

OBJECTIVE

The present study was performed to examine the relationships of gait independence with muscle thickness (MT) and echo intensity (EI) of the quadriceps femoris in individuals with hemiparesis after stroke.

METHODS

We examined 43 individuals with hemiparetic stroke. We assessed functional independence measure (FIM) gait scores and measured thickness and EI of the quadriceps using US. The relationships of FIM gait scores with MT and EI were examined using Spearman's correlation coefficients in mild (n = 21) and severe (n = 22) hemiparetic stroke groups.

RESULTS

In the mild hemiparetic group, FIM gait scores were correlated with paretic limb MT (rho = 0.60, p < 0.01) and EI (rho = -0.57, p < 0.01). In the severe hemiparetic group, FIM gait scores were correlated with paretic limb MT (rho = 0.67, p < 0.01) and EI (rho = -0.43, p < 0.05), as well as non-paretic limb MT (rho = 0.86, p < 0.01) and EI (rho = -0.56, p < 0.01).

CONCLUSIONS

Quadriceps thickness and EI were associated with the degree of gait independence. Atrophy and increased intramuscular fat of the quadriceps may be limiting factors for achieving gait independence.

Limited fascicle shortening and fascicle rotation may be associated with impaired voluntary force-generating capacity in pennate muscles of chronic stroke survivors

BACKGROUND

Muscle weakness is one of the most common motor impairments after stroke. A variety of progressive muscular changes are reported in chronic stroke survivors, and it is now feasible to consider these changes as an added source of weakness. However, the net contributions of such muscular changes towards muscle weakness have not been fully quantified.

METHODS

Accordingly, this study aims: (1) to compare muscle architecture of the human medial gastrocnemius between paretic and non-paretic sides in seven chronic hemispheric stroke survivors under passive conditions; (2) to characterize fascicle behavior (i.e., fascicle shortening and fascicle rotation) of the muscle during voluntary isometric contractions; and (3) to assess potential associations between muscle architectural parameters and muscle weakness. Muscle architecture of the medial gastrocnemius (including fascicle length, fascicle pennation angle, and muscle thickness) was characterized using B-mode ultrasonography, and fascicle behavior was then quantified as a function of isometric plantarflexion torque normalized to body mass.

FINDINGS

Our experimental results showed that under passive conditions, there was a significant difference in fascicle length and muscle thickness between paretic and non-paretic muscles, but no difference in resting fascicle pennation angle. However, during isometric contraction, both fascicle shortening and fascicle rotation on the paretic side were significantly decreased, compared to the non-paretic side. Moreover, the relative (i.e., paretic/non-paretic) fascicle rotation-shortening ratio (i.e., fascicle rotation per fascicle shortening) was strongly correlated with the relative maximum voluntary isometric plantarflexion torque.

INTERPRETATION

This association implies that such fascicle changes could impair the force-generating capacity of the muscle in chronic stroke survivors.

Long-term use of implanted peroneal functional electrical stimulation for stroke-affected gait: the effects on muscle and motor nerve

BACKGROUND

Peripheral changes to muscle and motor nerves occur following stroke, which may further impair functional capacity. We investigated whether a year-long use of an implanted peroneal FES system reverses stroke-related changes in muscles and motor nerves in people with foot drop in the chronic phase after supratentorial stroke.

METHODS

Thirteen persons with a chronic stroke (mean age 56.1 years, median Fugl-Meyer Assessment leg score 71%) were included and received an implanted peroneal FES system (ActiGait®). Quantitative muscle ultrasound (QMUS) images were obtained bilaterally from three leg muscles (i.e. tibialis anterior, rectus femoris, gastrocnemius). Echogenicity (muscle ultrasound gray value) and muscle thickness were assessed over a one-year follow-up and compared to age-, sex-, height- and weight-corrected reference values. Compound motor action potentials (CMAPs) and motor evoked potentials (MEPs) were obtained from the tibialis anterior muscle. Generalized estimated equation modeling was used to assess changes in QMUS, CMAPs and MEPs outcomes over the follow-up period.

RESULTS

Echogenicity of the tibialis anterior decreased significantly during the follow-up on the paretic side. Z-scores changed from 0.88 at baseline to - 0.15 after 52 weeks. This was accompanied by a significant increase in muscle thickness on the paretic side, where z-scores changed from - 0.32 at baseline to 0.48 after 52 weeks. Echogenicity of the rectus femoris normalized on both the paretic and non-paretic side (z-scores changed from - 1.09 and - 1.51 to 0.14 and - 0.49, respectively). Amplitudes of CMAP and MEP (normalized to CMAP) were reduced during follow-up, particularly on the paretic side (ΔCMAP = 20% and ΔMEP = 14%).

CONCLUSIONS

We show that the structural changes to muscles following stroke are reversible with FES and that these changes might not be limited to electrically stimulated muscles. No evidence for improvement of the motor nerves was found.

Low body mass index negatively affects muscle mass and intramuscular fat of chronic stroke survivors

Objective

Relationship between secondary changes in skeletal muscle and body weight in chronic stroke survivors has not yet been carefully examined. The objective of this study was to clarify the relationships between muscle mass, intramuscular fat, and body weight in chronic stroke survivors.

Methods

Seventy-two chronic stroke survivors participated in this study. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Quadriceps muscle mass and intramuscular fat were assessed based on muscle thickness and echo intensity, respectively. We used a stepwise multiple regression analysis to identify the factors that were independently associated with the body mass index. We entered quadriceps thickness and echo intensity of the paretic and non-paretic sides into another stepwise multiple regression model to avoid multicollinearity. Age, sex, type of stroke, time since stroke, thigh length, number of medications, and an updated Charlson comorbidity index were included as the independent variables.

Results

The quadriceps thickness and echo intensity of the paretic and non-paretic sides were significantly independently associated with the body mass index: quadriceps thickness of the paretic side, β = 0.52; quadriceps thickness of the non-paretic side, β = 0.55; quadriceps echo intensity of the paretic side, β = −0.35; quadriceps echo intensity of the non-paretic side, β = −0.27).

Conclusions

Our results suggest that low body mass index is associated with loss of muscle mass and increased intramuscular fat on both the paretic and non-paretic sides of chronic stroke survivors. Further studies examining whether appropriate weight management, along with targeted rehabilitation programs aimed at increasing muscle mass and decreasing intramuscular fat, achieves good outcomes in chronic stroke survivors are warranted.

Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors: A cross-sectional study

Objective

Improving muscle mass and intramuscular fat in the mid-thigh increases the muscle strength of the paretic and non-paretic limbs in ambulatory chronic stroke survivors. There is a remarkable decrease in muscle mass and muscle strength and an increase in intramuscular fat in the quadriceps of both limbs of non-ambulatory compared with ambulatory survivors. Therefore, given that paretic lower extremity function does not recover sufficiently in the chronic phase, it may be helpful to improve muscle mass and intramuscular fat to increase muscle strength in the quadriceps of non-ambulatory chronic stroke survivors. However, these relationships remain unclear. The purpose of this study was to clarify the relationships between muscle strength, muscle mass, and intramuscular fat of the quadriceps in non-ambulatory chronic stroke survivors.

Methods

Study design: A cross-sectional study.

Participants: Fifty non-ambulatory chronic stroke survivors.

Main outcome measures: Quadriceps muscle strength was measured using a handheld dynamometer. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular fat of the quadriceps were assessed based on muscle thickness and echo intensity, respectively.

Data analysis: Stepwise multiple regression analyses were used to identify the factors independently associated with the quadriceps muscle strength of the paretic and non-paretic limbs. To avoid multicollinearity, muscle thickness and echo intensity were entered into separate multiple regression models. Muscle thickness or echo intensity of the paretic or non-paretic limbs and other confounding factors were set as the independent variables.

Results

Muscle thickness was positively related and echo intensity was negatively related to the quadriceps muscle strength of the paretic and non-paretic limbs.

Conclusions

Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors. Increasing muscle mass and decreasing intramuscular fat of the quadriceps of both limbs may improve muscle strength.