BACKGROUND: Individuals with spinal cord injury (SCI) can experience accelerated cognitive aging. Myokines (factors released from muscle cells during contractions), such as brain-derived neurotrophic factor (BDNF), are thought to have beneficial effects on cognition. Neuromuscular electrical stimulation (NMES) was shown to elicit a large release of myokines. However, the effects of NMES on cognitive function have not been studied.
OBJECTIVE: To present the study protocol for a clinical trial evaluating the effects of NMES aimed at improving cognition and BDNF.
METHODS: A replicated randomized three-phases single-case experimental design (SCED) with sequential multiple baseline time series and a single-armed prospective trial will be conducted with 15 adults with chronic SCI (> 12 months after injury) above L1 neurological level undergoing 30-min quadriceps NMES, 3 days per week for 12 weeks.
UNASSIGNED: Primary endpoint is cognitive performance (assessed by a smartphone test) conducted three times per week during the baseline phase with random duration of 3 to 8 weeks, the intervention phase of 12 weeks, and the follow-up phase of 3 weeks after a no measurement rest period of 12 weeks. Secondary endpoints are changes in BDNF levels and cognitive performance measured before the baseline period, before and after intervention and after a 12 weeks follow-up.
CONCLUSIONS: This will be the first study investigating the effects of 12 weeks NMES on both cognition and BDNF levels in individuals with SCI. The SCED results provide information on individual treatment effect courses which may direct future research.
BACKGROUND: ClinicalTrials.gov (NCT05822297, 12/01/2023).

BACKGROUND: The aging brain exhibits a neuroinflammatory state, driven partly by peripheral pro-inflammatory stimuli, that accelerates cognitive deterioration. A growing body of evidence clearly indicates that physical exercise partly alleviates neuroinflammation and positively affects the aging process and cognition. In this randomized controlled trial, we aimed to observe the effect of 12 weeks of resistance training (RT) on peripheral biomarker levels, cognitive function changes and their interrelationship, and explore differences in those exercise-induced changes in older adults with high risk of mild cognitive impairment (MCI) compared to older adults with low risk of MCI.
METHODS: Fifty-two participants (aged 60-85 years old, 28 female) were randomly allocated to a 12 week lower limb RT program consisting of two training sessions per week or waiting list control group. The Montreal Cognitive Assessment (MoCA) was used to stratify participants screened as high (< 26/30) or low risk (≥ 26/30) of MCI. We assessed serum Interleukin 6 (IL-6), Insulin-like Growth Factor-1 (IGF-1), and Kynurenine (KYN) levels. Cognitive measurement consisted of and four subtests of Automated Neuropsychological Assessment Metrics (ANAM), the two-choice reaction time, go/no-go, mathematical processing, and memory search test.
RESULTS: Twelve weeks of RT improved Go/No-go test results in older adults with high MCI risk. RT did not significantly affect blood biomarkers. However, IGF-1 level increases were associated with improvements in response time on the mathematical processing test in the exercise group, and IL-6 level increases were associated with improvements in response time on the memory search test in the total group of participants. Finally, KYN levels significantly differed between older adults with low and high MCI risk but no significant associations with performance were found.
CONCLUSIONS: Our study results suggest a different effect of RT on inhibitory control between older adults with low compared to high MCI risk. IGF-1 may play a role in the mechanism behind the cognitive benefit of RT and KYN may be a surrogate biomarker for neurodegeneration and cognitive decline.

Introduction Irisin, a newly discovered myokine, has been reported for its role in coronary artery disease (CAD), which is a major cause of mortality worldwide. Atherosclerosis is the primary cause of CAD. Irisin has been reported to reduce atherosclerosis by improving endothelial function and inhibiting inflammation via iNOS/NF-κB pathways. We sought to investigate the relationship between serum irisin levels and the severity of CAD that is confirmed with coronary angiography. Methods A comparative cross-sectional study was designed between the Chemical Pathology and Cardiology departments at KEMU/Mayo Hospital in Lahore, Pakistan. Patients were divided into group A with mild CAD (<50% stenosis) and group B with moderate-severe CAD (>50% stenosis). Serum was collected from venous blood, and irisin levels were analyzed by ELISA. Inclusion criteria: patients with stable CAD. Exclusion criteria: History of coronary artery bypass grafting (CABG), acute coronary syndrome (ACS), active or chronic infection, hepatic or renal dysfunction. Results The mean + SD age (years) of patients in group B (57.0±9.5) was significantly higher than group A (50.0±13.7). Irisin levels (μg/ml) were significantly higher in group A (15.3±4.6) than in group B (9.3±2.4). Irisin levels were significantly negatively correlated with the severity of CAD (% stenosis). Conclusion Serum irisin levels are low in patients with moderate to severe CAD, and they are negatively correlated with the severity of CAD (% stenosis).

The activins-follistatins-inhibins (AFI) hormonal system is considered to regulate muscle and bone mass. We aimed to evaluate AFI in postmenopausal women with an incident hip fracture.
In this post-hoc analysis of a hospital based case-control study, we evaluated circulating levels of the AFI system in postmenopausal women with a low-energy hip fracture admitted for fixation compared with postmenopausal women with osteoarthritis scheduled for arthroplasty.
Circulating levels of follistatin (p = 0.008), FSTL3 (p = 0.013), activin B and AB (both p < 0.001), as well as activin AB/follistatin and activin AB/FSTL3 ratios (p = 0.008 and p = 0.029, respectively) were higher in patients than controls in unadjusted models. Differences for activins B and AB remained after adjustment for age and BMI (p = 0.006 and p = 0.009, respectively) and for FRAX-based risk for hip fracture (p = 0.008 and p = 0.012, respectively) but were lost when 25OHD was added to the regression models.
Our data indicate no major changes in the AFI system in postmenopausal women at the time of hip fracture compared to postmenopausal women with osteoarthritis except for higher activin B and AB levels, whose significance, however, was lost when 25OHD was added to the adjustment models.
Clinical Trials identifier: NCT04206618.

Electrical muscle stimulation (EMS) is a widely used method in sports and rehabilitation therapies to simulate physical exercise. EMS treatment via skeletal muscle activity improves the cardiovascular functions and the overall physical condition of the patients. However, the cardioprotective effect of EMS has not been proven so far, therefore, the aim of this study was to investigate the potential cardiac conditioning effect of EMS in an animal model. Low-frequency 35-min EMS was applied to the gastrocnemius muscle of male Wistar rats for three consecutive days. Their isolated hearts were then subjected to 30 min global ischemia and 120 min reperfusion. At the end of reperfusion cardiac specific creatine kinase (CK-MB) and lactate dehydrogenase (LDH) enzyme release and myocardial infarct size were determined. Additionally, skeletal muscle-driven myokine expression and release were also assessed. Phosphorylation of cardioprotective signaling pathway members AKT, ERK1/2, and STAT3 proteins were also measured. EMS significantly attenuated cardiac LDH and CK-MB enzyme activities in the coronary effluents at the end of the ex vivo reperfusion. EMS treatment considerably altered the myokine content of the stimulated gastrocnemius muscle without altering circulating myokine levels in the serum. Additionally, phosphorylation of cardiac AKT, ERK1/2, and STAT3 was not significantly different in the two groups. Despite the lack of significant infarct size reduction, the EMS treatment seems to influence the course of cellular damage due to ischemia/reperfusion and favorably modifies skeletal muscle myokine expressions. Our results suggest that EMS may have a protective effect on the myocardium, however, further optimization is required.

The impact of combined aerobic and resistance exercise on Klotho (KL) secretion is unclear. Twelve healthy young men completed two randomized experimental trials: 1) resistance exercise (RE) and 2) resistance exercise with prior aerobic exercise (AE + RE). Following baseline blood pressure assessment and blood collection, the subjects in the RE trial maintained a supine position for 45 min, while the subjects in the AE + RE trial performed 45 min of aerobic exercise. After 45 min of resting or aerobic exercise, all subjects performed resistance exercise. Following resistance exercise, the subjects rested in a supine position for 60 min. Blood pressure assessment and blood collection were repeated. Aerobic and resistance exercise significantly increased serum KL concentrations, respectively (P < 0.05), and no additive effect of aerobic exercise on KL secretion was observed immediately after resistance exercise in the AE + RE trial compared with the RE trial. However, serum KL levels at 30 and 60 min after resistance exercise were significantly higher in the AE + RE trial than in the RE trial. Serum ET-1 concentrations were significantly increased only in the RE trial. In conclusion, combined aerobic and resistance exercise could maintain higher levels of serum KL secretion after exercise compared with resistance exercise only.

Resistance training and protein supplementation are expected to exert the greatest effect in counteracting muscle-wasting conditions. Myokines might play a key role, but this remains to be elucidated. The aim of this study (NCT03815201) was to examine the effects of a resistance training program with post-exercise leucine-enriched protein supplementation on sarcopenia and frailty status and on the plasma myokine concentrations of post-hospitalized older adults. A total of 41 participants were included in this 12-week resistance training intervention and randomized either to the placebo group or the protein group. Sarcopenia, frailty, body composition and blood-based myokines were measured at baseline and after 12 weeks. Both groups improved in terms of physical performance (p < 0.005) and frailty (p < 0.07) following the resistance training intervention, but without any difference between groups. Myokine concentrations did not change after the intervention in either group. Changes in myostatin concentrations were associated with greater improvements in appendicular skeletal muscle mass at the end of the intervention (p < 0.05). In conclusion, the implementation of resistance training programs after hospitalization in older adults should be prioritized to combat sarcopenia and frailty immediately. The results regarding myostatin should be taken as preliminary findings.

OBJECTIVE: Exercise is effective for the prevention of liver cancer. Exercise exerts biological effects through the regulation of microRNAs (miRNAs) and cytokines/myokines. We aimed to investigate the effects of low-intensity resistance exercise on serum miRNA and cytokine/myokine expressions in subjects with no exercise habits.
METHODS: We enrolled seven male subjects with no exercise habits in this prospective before-after study. All subjects performed a low-intensity resistance exercise program (three metabolic equivalents, approximately 20 min/session). Serum miRNA expressions were evaluated using microarrays. We performed Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of differentially expressed miRNAs before and after exercise. Serum cytokine/myokine expressions were evaluated using a multiplex panel.
RESULTS: All subjects completed the exercise program with no adverse events. In the microarray analysis, seven miRNAs showed a significant change between before and after exercise. Of these, microRNA (miR)-630 and miR-5703 showed a >1.5-fold increase (miR-630: 40.7 vs. 69.3 signal intensity, p = 0.0133; miR-5703: 30.7 vs. 55.9 signal intensity, p = 0.0051). KEGG pathway enrichment analysis showed that miR-630- and miR-5703-related genes were enriched in 37 and 5 pathways, including transforming growth factor-beta and Wnt signaling pathways, respectively. In the multiplex analysis, 12 cytokines/myokines showed significant alteration after exercise compared to before exercise. Of these, fractalkine/CX3CL1 showed the most significant up-regulation by exercise (94.5 vs. 109.1 pg/ml, p = 0.0017).
CONCLUSIONS: A low-intensity resistance exercise program was associated with upregulation of serum miR-630, miR-5703, and fractalkine/CX3CL1 expressions in subjects with no exercise habits. Thus, even low-intensity exercise may alter miRNA and cytokine/myokine expressions in humans.

Insulin resistance is associated with the progression of nonalcoholic fatty liver disease (NAFLD). Insulin resistance is regulated by various cytokines, including interleukin-6 (IL-6), a proinflammatory myokine, and selenoprotein P (SeP), a liver-derived secretory hepatokine. High levels of IL-6 and/or SeP have been shown to contribute to insulin resistance, and exercise is a first-line therapy for NAFLD. We have developed a hybrid training system (HTS): a neuromuscular electrical stimulation device to enhance exercise results. We aimed to investigate the effects of HTS on insulin resistance as well as serum IL-6 and SeP in patients with NAFLD. This is a randomized, single-blind (assessor), controlled trial. Subjects with NAFLD walked on a treadmill with or without HTS (9 subjects each) for 30 minutes three times a week for six weeks (HTS vs. control group; median age 45 vs. 45; male/female 5/4 vs. 6/3). We examined subjects before the first session and at the end of the final session. Serum SeP levels were measured by ELISA which measures the fragment of SeP. In the HTS group, HOMA-IR values were significantly reduced compared to the control group (Δ-0.71 vs. Δ0.05; P < 0.05). IL-6 and SeP levels in serum were also significantly reduced compared to that of the control group (IL-6; Δ-0.6 vs. Δ0.29 pg/mL; P < 0.05, SeP; Δ-1288.5 vs. Δ-435.4 ng/mL; P < 0.05, respectively). In conclusion, we propose that HTS improves insulin resistance by reducing serum IL-6 and SeP levels in patients with NAFLD.

We investigated the effect of chitinase-3-like protein 1 (CHI3L1) on glucose metabolism and its underlying mechanisms in skeletal muscle cells, and evaluated whether the observed effects are relevant in humans. CHI3L1 was associated with increased glucose uptake in skeletal muscles in an AMP-activated protein kinase (AMPK)-dependent manner, and with increased intracellular calcium levels via PAR2. The improvement in glucose metabolism observed in an intraperitoneal glucose tolerance test on male C57BL/6J mice supported this association. Inhibition of the CaMKK was associated with suppression of CHI3L1-mediated glucose uptake. Additionally, CHI3L1 was found to influence glucose uptake through the PI3K/AKT pathway. Results suggested that CHI3L1 stimulated the phosphorylation of AS160 and p38 MAPK downstream of AMPK and AKT, and the resultant GLUT4 translocation. In primary myoblast cells, stimulation of AMPK and AKT was observed in response to CHI3L1, underscoring the biological relevance of CHI3L1. CHI3L1 levels were elevated in cells under conditions that mimic exercise in vitro and in exercised mice in vivo, indicating that CHI3L1 is secreted during muscle contraction. Finally, similar associations between CHI3L1 and metabolic parameters were observed in humans alongside genotype associations between CHI3L1 and diabetes at the population level. CHI3L1 may be a potential therapeutic target for the treatment of diabetes.