High-intensity interval training-induced hypertrophy in gastrocnemius muscle via improved IGF-I/Akt/FoxO and myostatin/Smad signaling pathways in rats

Role of nutrition in patients with coexisting chronic obstructive pulmonary disease and sarcopenia

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic diseases in the elderly population and is characterized by persistent respiratory symptoms and airflow obstruction. During COPD progression, a variety of pulmonary and extrapulmonary complications develop, with sarcopenia being one of the most common extrapulmonary complications. Factors that contribute to the pathogenesis of coexisting COPD and sarcopenia include systemic inflammation, hypoxia, hypercapnia, oxidative stress, protein metabolic imbalance, and myocyte mitochondrial dysfunction. These factors, individually or in concert, affect muscle function, resulting in decreased muscle mass and strength. The occurrence of sarcopenia severely affects the quality of life of patients with COPD, resulting in increased readmission rates, longer hospital admission, and higher mortality. In recent years, studies have found that oral supplementation with protein, micronutrients, fat, or a combination of nutritional supplements can improve the muscle strength and physical performance of these patients; some studies have also elucidated the possible underlying mechanisms. This review aimed to elucidate the role of nutrition among patients with coexisting COPD and sarcopenia.

Role of muscle FOXO gene in exercise against the skeletal muscle and cardiac age-related defects and mortality caused by high-salt intake in Drosophila

FOXO has long been associated with aging, exercise, and tissue homeostasis, but it remains unclear what the role is of the muscle FOXO gene in E against high-salt intake(HSI)-induced age-related defects of the skeletal muscle, heart, and mortality. In this research, overexpression and RNAi of the FOXO gene in the skeletal and heart muscle of Drosophila were constructed by building Mhc-GAL4/FOXO-UAS-overexpression and Mhc-GAL4/FOXO-UAS-RNAi system. The skeletal muscle and heart function, the balance of oxidation and antioxidant, and mitochondrial homeostasis were measured. The results showed that exercise reversed the age-related decline in climbing ability and downregulation of muscle FOXO expression induced by HSI. Muscle-specific FOXO-RNAi (FOXO-RNAi) and -overexpression (FOXO-OE) promoted or slowed the age-related decline in climbing ability, heart function, and skeletal muscle and heart structure damage, which was accompanied by the inhibition or activation of FOXO/PGC-1α/SDH and FOXO/SOD pathway activity, and oxidative stress (ROS) increased or decreased in both skeletal muscle and heart. The protective effect of exercise on the skeletal muscle and heart was blocked by FOXO-RNAi in aged HSI flies. FOXO-OE prolonged its lifespan, but it did not resist the HSI-induced lifespan shortening. Exercise did not improve HSI-induced lifespan shortening in FOXO-RNAi flies. Therefore, current results confirmed that the muscle FOXO gene played a vital role in exercise against age-related defects of the skeletal muscle and heart induced by HSI because it determined the activity of muscle FOXO/SOD and FOXO/PGC-1α/SDH pathways. The muscle FOXO gene also played an important role in exercise against HSI-induced mortality in aging flies.

Functional and postoperative outcomes after high-intensity interval training in lung cancer patients: A systematic review and meta-analysis

Objective

The study evaluated the effects of high-intensity interval training (HIIT) on postoperative complications and lung function in patients with lung cancer compared to usual care.

Methods

We searched electronic databases in April 2022, including PubMed, Embase, the Cochrane Library, Web of Science, and the China National Knowledge Infrastructure (CNKI). Two authors independently applied the Cochrane Risk of Bias tool to assess the quality of RCTs. The postoperative complications, length of hospitalization, and cardiopulmonary functions from the studies were pooled for statistical analysis.

Results

A total of 12 randomized controlled trials were eligible for inclusion and were conducted in the meta-analysis. HIIT significantly increased VO_2peak (MD = 2.65; 95% CI = 1.70 to 3.60; I² = 40%; P <0.001) and FEV1 (MD = 0.12; 95% CI = 0.04 to 0.20; I² = 51%; P = 0.003) compared with usual care. A subgroup analysis of studies that applied HIIT perioperatively showed significant improvement of HIIT on FEV1 (MD = 0.14; 95% CI = 0.08 to 0.20; I² = 36%; P <0.0001). HIIT significantly reduced the incidence of postoperative atelectasis in lung cancer patients compared with usual care (RD = -0.16; 95% CI = -0.24 to -0.08; I² = 24%; P <0.0001). There was no statistically significant effect of HIIT on postoperative arrhythmias (RD = -0.05; 95% CI = -0.13 to 0.03; I² = 40%; P = 0.22), length of hospitalization (MD = -1.64; 95% CI = -3.29 to 0.01; P = 0.05), and the six-minute walk test (MD = 19.77; 95% CI = -15.25 to 54.80; P = 0.27) compared to usual care.

Conclusion

HIIT may enhance VO_2peak and FEV1 in lung cancer patients and reduce the incidence of postoperative atelectasis. However, HIIT may not reduce the incidence of postoperative arrhythmia, shorten the length of hospitalization, or improve the exercise performance of patients with lung cancer.

Systematic review registration

PROSPERO, CRD42022335441.

The effect of high-intensity interval training (HIIT) on protein expression in Flexor Hallucis Longus (FHL) and soleus (SOL) in rats with type 2 diabetes

Purpose

In people with diabetes, one of the problems for patients is muscle wasting and inhibition of the protein synthesis pathway. This study aimed to evaluate the effects of HIIT on protein expression in two skeletal muscles, flexor hallucis longus (FHL) and soleus (SOL) in rats with type 2 diabetes mellitus (T2DM).

Materials and methods

Diabetes initially was induced by streptozotocin (STZ) and nicotinamide. Rats with type 2 diabetes were randomly and equally divided into control (n = 6) and HIIT groups (n = 6). After 8 weeks of training, the content of total and phosphorylated proteins of serine/threonine-protein kinases (AKT1), mammalian target of rapamycin (mTOR), P70 ribosomal protein S6 kinase 1 (P70S6K1), and 4E (eIF4E)-binding protein 1 (4E-BP1) in FHL and SOL muscles were measured by Western blotting. While body weight and blood glucose were also controlled.

Results

In the HIIT training group, compared to the control group, a significant increase in the content of AKT1 (0.003) and mTOR (0.001) proteins was observed in the FHL muscle. Also, after 8 weeks of HIIT training, protein 4E-BP1 (0.001) was increased in SOL muscle. However, there was no significant change in other proteins in FHL and SOL muscle.

Conclusions

In rats with type 2 diabetes appear to HIIT leading to more protein expression of fast-twitch muscles than slow-twitch muscles. thus likely HIIT exercises can be an important approach to increase protein synthesis and prevent muscle atrophy in people with type 2 diabetes.

Time-Dependent Cortical Plasticity during Moderate-Intensity Continuous Training Versus High-Intensity Interval Training in Rats

The temporal pattern of cortical plasticity induced by high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) is required to clarify their relative benefits to prevent neurological disorders. The purpose of this study is to define the time-dependent effects of work-matched HIIT and MICT on cortical plasticity, endurance, and sensorimotor performances over an 8-week training period in healthy rats. Adult healthy rats performed incremental exercise tests and sensorimotor tests before and at 2, 4, and 8 weeks of training. In parallel, cortical markers related to neurotrophic, angiogenic, and metabolic activities were assessed. Results indicate that HIIT induced an early and superior endurance improvement compared to MICT. We found significant enhancement of speed associated with lactate threshold (SLT) and maximal speed (Smax) in HIIT animals. MICT promoted an early increase in brain-derived neurotrophic factor and angiogenic/metabolic markers but showed less influence at 8 weeks. HIIT upregulated the insulin-like growth factor-1 (IGF-1) as well as neurotrophic, metabolic/angiogenic markers at 2 and 8 weeks and downregulated the neuronal K-Cl cotransporter KCC2 that regulates GABAA-mediated transmission. HIIT and MICT are effective in a time-dependent manner suggesting a complementary effect that might be useful in physical exercise guidelines for maintaining brain health.

Beta-hydroxy-beta-methylbutyrate associated with low-intensity exercise training improves skeletal muscle regeneration through the IGF-Akt pathway

The effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation associated with exercise training at different intensities and frequencies on skeletal muscle regeneration of muscle-injured rats was investigated. Male Wistar rats were divided into sedentary and trained groups. The sedentary groups were subdivided into non-injured (SED-Ct), non-injured supplemented with HMB (SED-Ct-HMB), injured (SED), and injured with HMB (SED-HMB), and the trained groups were injured, supplemented with HMB, and then divided into training three times a week without load (HT3) or with load (HT3L) and training five times a week without load (HT5) and with load (HT5L). The rats received a daily dose of HMB associated with 60 min of swimming with or without 5% body mass load for 14 days. On the 15th day, cryoinjury was performed in the right tibialis anterior muscle (TA), and 48 h later, supplementation and training continued for 15 days. After the last session, the TA was dissected and a cross-sectional area (CSA) of muscle fibers was used to determine the percentage of CSA fibers and connective tissue (%CT), as well as the total and phosphorylated protein contents. SED-HMB showed increased CSA and decreased %CT and TGF-β when compared to SED. HT3 showed increased CSA and reduced %CT accompanied by increased IGF-1/Akt, myogenin, and MuRF1, and decreased TGF-β. The CSA of HT5L also increased, but at the cost of a higher %CT compared to the other groups. Our results demonstrated that HMB associated with training without load and with lower frequency per week may be a valuable strategy for skeletal muscle regeneration.

Effect of the order of concurrent training combined with resistance and high-intensity interval exercise on mTOR signaling and glycolytic metabolism in mouse skeletal muscle

Athletes train to improve strength and endurance to demonstrate maximum performance during competitions. Training methods vary but most focus on strength, endurance, or both. Concurrent training is a combination of two different modes of training. In this study, we combined resistance exercise (RE) and high-intensity interval exercise (HIIE) to investigate the influence of the order of the concurrent training on signal molecules on hypertrophy and glycolysis in the skeletal muscle. The phosphorylation levels of mechanistic target of rapamycin (mTOR) signals, p70 S6 kinase (p70S6 K), ribosomal protein S6 (S6), and glycogen synthase kinase beta (GSK-3β) were significantly increased in the HIIE first group compared with the control group. The combined training course did not affect the glycogen content and expression levels of proteins concerning glycolytic and metabolic capacity, suggesting that a combination of HIIE and RE on the same day, with HIIE prior to RE, improves hypertrophy response and glycolysis enhancement.

Linalool Prevents Cisplatin Induced Muscle Atrophy by Regulating IGF-1/Akt/FoxO Pathway

Skeletal muscle atrophy is an important feature of cancer cachexia, which can be induced by chemotherapy, and affects the survival and quality of life of cancer patients seriously. No specific drugs for cancer cachexia have been applied in clinical practice. This study explored the therapeutic effect of linalool (LIN) on cisplatin (DDP) induced skeletal muscle atrophy. In vivo, LIN can improve skeletal muscle weight loss, anorexia, muscle strength decline and other cachexia symptoms caused by cisplatin treatment in a Lewis lung cancer tumor bearing mouse model, and cause no adverse effects on the anti-tumour effect. LIN treatment decreased the expression of muscle RING-finger protein-1 (MuRF1) and Atrogin1(MAFbx) in muscle, and the activation of insulin-like growth factor-1 (IGF-1)/protein kinase B (Akt)/forkhead box O (FoxO) pathway was observed. In vitro, LIN alleviated DDP induced C2C12 myotube atrophy, and IGF-1 receptor inhibitor Picropodophyllin (PIC), which had no adverse effect on C2C12 myotube cells, could reverse the protective effect of LIN. These results indicate that LIN down-regulates the expression of Atrogin1 and MuRF1 through the IGF-1/Akt/FoxO pathway, alleviating DDP-induced muscle atrophy and improving cachexia symptoms. LIN has the potential to be developed as a drug against cancer cachexia.

Delivery of muscle-derived exosomal miRNAs induced by HIIT improves insulin sensitivity through down-regulation of hepatic FoxO1 in mice

Implementation of regular physical activity helps in the maintenance of a healthy metabolic profile both in humans and mice through molecular mechanisms not yet completely defined. Here, we show that high-intensity interval training (HIIT) modifies the microRNA (miRNA) profile of circulating exosomes in mice, including significant increases in miR-133a and miR-133b Importantly, treatment of sedentary mice with exosomes isolated from the plasma of trained mice improves glucose tolerance, insulin sensitivity, and decreases plasma levels of triglycerides. Moreover, exosomes isolated from the muscle of trained mice display similar changes in miRNA content, and their administration to sedentary mice reproduces the improvement of glucose tolerance. Exosomal miRNAs up-regulated by HIIT target insulin-regulated transcription factor forkhead box O1 (FoxO1) and, accordingly, expression of FoxO1 is decreased in the liver of trained and exosome-treated mice. Treatment with exosomes transfected with a miR-133b mimic or with a specific siRNA targeting FoxO1 recapitulates the metabolic effects observed in trained mice. Overall, our data suggest that circulating exosomes released by the muscle carry a specific miRNA signature that is modified by exercise and induce expression changes in the liver that impact whole-body metabolic profile.