Exercise preserves muscle mass and force in a prostate cancer mouse model

Influence of Amino Acids and Exercise on Muscle Protein Turnover, Particularly in Cancer Cachexia

Cancer cachexia is a multifaceted syndrome that impacts individuals with advanced cancer. It causes numerous pathological changes in cancer patients, such as inflammation and metabolic dysfunction, which further diminish their quality of life. Unfortunately, cancer cachexia also increases the risk of mortality in affected individuals, making it an important area of focus for cancer research and treatment. Several potential nutritional therapies are being tested in preclinical and clinical models for their efficacy in improving muscle metabolism in cancer patients. Despite promising results, no special nutritional therapies have yet been validated in clinical practice. Multiple studies provide evidence of the benefits of increasing muscle protein synthesis through an increased intake of amino acids or protein. There is also increasing evidence that exercise can reduce muscle atrophy by modulating protein synthesis. Therefore, the combination of protein intake and exercise may be more effective in improving cancer cachexia. This review provides an overview of the preclinical and clinical approaches for the use of amino acids with and without exercise therapy to improve muscle metabolism in cachexia.

Pilot Study on the Impact of a Home-Based Exercise Program on Inflammatory Cytokines and Quality of Life in Men with Prostate Cancer Under Active Surveillance

OBJECTIVES

This study aimed to demonstrate potential translation of pre-clinical studies to a home-based exercise intervention in mediating inflammatory cytokine markers and tumor progression in men under active surveillance for prostate cancer.

METHODS

A 2-arm randomized control parallel group design was used. The exercise intervention consisted of 24 weeks of an aerobic and resistance home-based exercise program and results were compared to a waitlist control group. Data were collected at baseline and end of study for eotaxin, interferon-γ (INF-γ), interleukin-12 (IL-12), interleukin-1α (IL-1α), interleukin-5 (IL-5), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and vascular endothelial growth factor (VEGF), distanced walked during a 6-minute walk test (6MWT), body mass index, and health-related quality of life.

RESULTS

Non-significant decreases were observed in all biomarkers, especially VEGF (pre: 125.16 ± 198.66, post: 80.29 ± 124.30, P = .06) and INF-γ (pre: 152.88 ± 312.71, post: 118.93 ± 158.79, P = .08), in the intervention group; only IL- α (pre: 332.15 ± 656.77, post: 255.12 ± 502.09, P = .20) decreased in the control group while all other biomarkers increased from baseline to end of study. A non-significant increase in 6MWT distance was observed in the intervention group, while a decrease was seen in the control group. Significant decreases in physical function, emotional wellbeing, and total composite scale on the FACIT-F were observed in the intervention group, possibly due to the isolation restrictions of COVID-19. Physical function on the SF-36 significantly increased in the control group.

CONCLUSIONS

Future studies with powered samples are needed to confirm the trends observed for inflammatory biomarkers and functional fitness.

Exercise and Creatine Supplementation to Augment the Adaptation of Exercise Training Among Breast Cancer Survivors Completing Chemotherapy: Protocol for an Open-label Randomized Controlled Trial (the THRIVE Study)

BACKGROUND

In breast cancer survivors, chemotherapy-induced muscle loss has been shown to be attenuated with structured resistance exercise. Creatine supplementation can increase bioenergetics in skeletal muscle, which helps to improve overall strength and endurance and reduce muscular fatigue. Therefore, we hypothesize that adding creatinine supplementation to exercise training will accelerate improvements in strength, endurance, and bioenergetics in breast cancer survivors.

OBJECTIVE

The primary objective is to determine the effects of combining creatine supplementation with exercise on modulating strength and physical function in breast cancer survivors by comparing these effects to those of exercise alone. The secondary objectives are to determine if creatine supplementation and exercise can increase the intramuscular storage of creatine and improve body composition by comparing this intervention to exercise alone.

METHODS

We aim to test our hypothesis by conducting an open-label randomized controlled trial of 30 breast cancer survivors who have completed chemotherapy within 6 months of enrollment. Eligible participants will be equally randomized (1:1) to either a creatine and exercise group or an exercise-only group for this 12-week intervention. Individuals who are randomized to receive creatine will be initially dosed at 20 g per day for 7 days to boost the availability of creatine systemically. Thereafter, the dose will be reduced to 5 g per day for maintenance throughout the duration of the 12-week protocol. All participants will engage in 3 center-based exercise sessions, which will involve completing 3 sets of 8 to 12 repetitions on chest press, leg press, seated row, shoulder press, leg extension, and leg curl machines. The primary outcomes will include changes in strength, body composition, and physical function in breast cancer survivors. The secondary outcomes will be intramuscular concentrations of creatine and adenosine triphosphate in the vastus lateralis, midthigh cross-sectional area, and quality of life.

RESULTS

As of October 2021, a total of 9 patients have been enrolled into the study. No unexpected adverse events have been reported.

CONCLUSIONS

Creatine is being studied as a potential agent for improving strength, endurance, and bioenergetics in breast cancer survivors following chemotherapy. The findings from our trial may have future implications for supporting breast cancer survivors in reversing the muscle loss experienced during chemotherapy and improving their physical function and quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04207359; https://clinicaltrials.gov/ct2/show/NCT04207359.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/26827.

The ERG1A K+ Channel Is More Abundant in Rectus abdominis Muscle from Cancer Patients Than that from Healthy Humans

BACKGROUND

The potassium channel encoded by the ether-a-gogo-related gene 1A (erg1a) has been detected in the atrophying skeletal muscle of mice experiencing either muscle disuse or cancer cachexia and further evidenced to contribute to muscle deterioration by enhancing ubiquitin proteolysis; however, to our knowledge, ERG1A has not been reported in human skeletal muscle.

METHODS AND RESULTS

Here, using immunohistochemistry, we detect ERG1A immunofluorescence in human Rectus abdominis skeletal muscle sarcolemma. Further, using single point brightness data, we report the detection of ERG1A immunofluorescence at low levels in the Rectus abdominis muscle sarcolemma of young adult humans and show that it trends toward greater levels (10.6%) in healthy aged adults. Interestingly, we detect ERG1A immunofluorescence at a statistically greater level (53.6%; p < 0.05) in the skeletal muscle of older cancer patients than in age-matched healthy adults. Importantly, using immunoblot, we reveal that lower mass ERG1A protein is 61.5% (p < 0.05) more abundant in the skeletal muscle of cachectic older adults than in healthy age-matched controls. Additionally, we report that the ERG1A protein is detected in a cultured human rhabdomyosarcoma line that may be a good in vitro model for the study of ERG1A in muscle.

CONCLUSIONS

The data demonstrate that ERG1A is detected more abundantly in the atrophied skeletal muscle of cancer patients, suggesting it may be related to muscle loss in humans as it has been shown to be in mice experiencing muscle atrophy as a result of malignant tumors.

Skeletal Muscle-Adipose Tissue-Tumor Axis: Molecular Mechanisms Linking Exercise Training in Prostate Cancer

Increased visceral adiposity may influence the development of prostate cancer (PCa) aggressive tumors and cancer mortality. White adipose tissue (WAT), usually referred to as periprostatic adipose tissue (PPAT), surrounds the prostatic gland and has emerged as a potential mediator of the tumor microenvironment. Exercise training (ET) induces several adaptations in both skeletal muscle and WAT. Some of these effects are mediated by ET-induced synthesis and secretion of several proteins, known as myo- and adipokines. Together, myokines and adipokines may act in an endocrine-like manner to favor communication between skeletal muscle and WAT, as they may work together to improve whole-body metabolic health. This crosstalk may constitute a potential mechanism by which ET exerts its beneficial role in the prevention and treatment of PCa-related disorders; however, this has not yet been explored. Therefore, we reviewed the current evidence on the effects of skeletal muscle–WAT–tumor crosstalk in PCa, and the potential mediators of this process to provide a better understanding of underlying ET-related mechanisms in cancer.

Definition of Sarcopenia in Chronic Liver Disease

Sarcopenia, which is characterized by decline in muscle mass, muscle strength, and physical performance, is common in patients with chronic liver disease (CLD) and is associated with poor clinical outcomes. Several consensus definitions for community-dwelling elderly people have been proposed, and these recommend the use of various tools and tests to assess muscle properties and performance. These measurement tools have also been applied in patients with CLD and have been useful for predicting prognosis. However, sarcopenia and its diagnostic criteria specific to patients with CLD have not yet been clearly defined. In addition, fluid retention and body composition should be considered when sarcopenia is assessed in patients with CLD. This review aims to introduce definitions of sarcopenia and diagnostic tools used in patients with CLD.

A Pound of Flesh: What Cachexia Is and What It Is Not

Body weight loss, mostly due to the wasting of skeletal muscle and adipose tissue, is the hallmark of the so-called cachexia syndrome. Cachexia is associated with several acute and chronic disease states such as cancer, chronic obstructive pulmonary disease (COPD), heart and kidney failure, and acquired and autoimmune diseases and also pharmacological treatments such as chemotherapy. The clinical relevance of cachexia and its impact on patients’ quality of life has been neglected for decades. Only recently did the international community agree upon a definition of the term cachexia, and we are still awaiting the standardization of markers and tests for the diagnosis and staging of cancer-related cachexia. In this review, we discuss cachexia, considering the evolving use of the term for diagnostic purposes and the implications it has for clinical biomarkers, to provide a comprehensive overview of its biology and clinical management. Advances and tools developed so far for the in vitro testing of cachexia and drug screening will be described. We will also evaluate the nomenclature of different forms of muscle wasting and degeneration and discuss features that distinguish cachexia from other forms of muscle wasting in the context of different conditions.

Exercise as a therapy for cancer-induced muscle wasting

Cancer cachexia is a progressive disorder characterized by body weight, fat, and muscle loss. Cachexia induces metabolic disruptions that can be analogous and distinct from those observed in cancer, obscuring both diagnosis and treatment options. Inflammation, hypogonadism, and physical inactivity are widely investigated as systemic mediators of cancer-induced muscle wasting. At the cellular level, dysregulation of protein turnover and energy metabolism can negatively impact muscle mass and function. Exercise is well known for its anti-inflammatory effects and potent stimulation of anabolic signaling. Emerging evidence suggests the potential for exercise to rescue muscle's sensitivity to anabolic stimuli, reduce wasting through protein synthesis modulation, myokine release, and subsequent downregulation of proteolytic factors. To date, there is no recommendation for exercise in the management of cachexia. Given its complex nature, a multimodal approach incorporating exercise offers promising potential for cancer cachexia treatment. This review's primary objective is to summarize the growing body of research examining exercise regulation of cancer cachexia. Furthermore, we will provide evidence for exercise interactions with established systemic and cellular regulators of cancer-induced muscle wasting.

Nutraceuticals and Exercise against Muscle Wasting during Cancer Cachexia

Cancer cachexia (CC) is a debilitating multifactorial syndrome, involving progressive deterioration and functional impairment of skeletal muscles. It affects about 80% of patients with advanced cancer and causes premature death. No causal therapy is available against CC. In the last few decades, our understanding of the mechanisms contributing to muscle wasting during cancer has markedly increased. Both inflammation and oxidative stress (OS) alter anabolic and catabolic signaling pathways mostly culminating with muscle depletion. Several preclinical studies have emphasized the beneficial roles of several classes of nutraceuticals and modes of physical exercise, but their efficacy in CC patients remains scant. The route of nutraceutical administration is critical to increase its bioavailability and achieve the desired anti-cachexia effects. Accumulating evidence suggests that a single therapy may not be enough, and a bimodal intervention (nutraceuticals plus exercise) may be a more effective treatment for CC. This review focuses on the current state of the field on the role of inflammation and OS in the pathogenesis of muscle atrophy during CC, and how nutraceuticals and physical activity may act synergistically to limit muscle wasting and dysfunction.