Effects of strength training on muscle cellular outcomes in prostate cancer patients on androgen deprivation therapy

Molecular mechanisms of cancer cachexia. Role of exercise training

Cancer-associated cachexia represents a multifactorial syndrome mainly characterized by muscle mass loss, which causes both a decrease in quality of life and anti-cancer therapy failure, among other consequences. The definition and diagnostic criteria of cachexia have changed and improved over time, including three different stages (pre-cachexia, cachexia, and refractory cachexia) and objective diagnostic markers. This metabolic wasting syndrome is characterized by a negative protein balance, and anti-cancer drugs like chemotherapy or immunotherapy exacerbate it through relatively unknown mechanisms. Due to its complexity, cachexia management involves a multidisciplinary strategy including not only nutritional and pharmacological interventions. Physical exercise has been proposed as a strategy to counteract the effects of cachexia on skeletal muscle, as it influences the mechanisms involved in the disease such as protein turnover, inflammation, oxidative stress, and mitochondrial dysfunction. This review will summarize the experimental and clinical evidence of the impact of physical exercise on cancer-associated cachexia.

Effects of heavy-load strength training during (neo-)adjuvant chemotherapy on muscle strength, muscle fiber size, myonuclei, and satellite cells in women with breast cancer

To investigate the effects of heavy-load strength training during (neo-)adjuvant chemotherapy in women with breast cancer on muscle strength, body composition, muscle fiber size, satellite cells, and myonuclei. Women with stage I-III breast cancer were randomly assigned to a strength training group (ST, n = 23) performing supervised heavy-load strength training twice a week during chemotherapy, or a usual care control group (CON, n = 17). Muscle strength and body composition were measured and biopsies from m. vastus lateralis collected before the first cycle of chemotherapy (T0) and after chemotherapy and training (T1). Muscle strength increased significantly more in ST than in CON in chest-press (ST: +10 ± 8%, p < .001, CON: -3 ± 5%, p = .023) and leg-press (ST: +11 ± 8%, p < .001, CON: +3 ± 6%, p = .137). Both groups reduced fat-free mass (ST: -4.9 ± 4.0%, p < .001, CON: -5.2 ± 4.9%, p = .004), and increased fat mass (ST: +15.3 ± 16.5%, p < .001, CON: +16.3 ± 19.8%, p = .015) with no significant differences between groups. No significant changes from T0 to T1 and no significant differences between groups were observed in muscle fiber size. For myonuclei per fiber a non-statistically significant increase in CON and a non-statistically significant decrease in ST in type I fibers tended (p = .053) to be different between groups. Satellite cells tended to decrease in ST (type I: -14 ± 36%, p = .097, type II: -9 ± 55%, p = .084), with no changes in CON and no differences between groups. Strength training during chemotherapy improved muscle strength but did not significantly affect body composition, muscle fiber size, numbers of satellite cells, and myonuclei compared to usual care.

The Role of Exercise in Cancer-Related Sarcopenia and Sarcopenic Obesity

One of the most common adverse effects of cancer and its therapeutic strategies is sarcopenia, a condition which is characterised by excess muscle wasting and muscle strength loss due to the disrupted muscle homeostasis. Moreover, cancer-related sarcopenia may be combined with the increased deposition of fat mass, a syndrome called cancer-associated sarcopenic obesity. Both clinical conditions have significant clinical importance and can predict disease progression and survival. A growing body of evidence supports the claim that physical exercise is a safe and effective complementary therapy for oncology patients which can limit the cancer- and its treatment-related muscle catabolism and promote the maintenance of muscle mass. Moreover, even after the onset of sarcopenia, exercise interventions can counterbalance the muscle mass loss and improve the clinical appearance and quality of life of cancer patients. The aim of this narrative review was to describe the various pathophysiological mechanisms, such as protein synthesis, mitochondrial function, inflammatory response, and the hypothalamic-pituitary-adrenal axis, which are regulated by exercise and contribute to the management of sarcopenia and sarcopenic obesity. Moreover, myokines, factors produced by and released from exercising muscles, are being discussed as they appear to play an important role in mediating the beneficial effects of exercise against sarcopenia.

Resistance Exercise Counteracts the Impact of Androgen Deprivation Therapy on Muscle Characteristics in Cancer Patients

CONTEXT

Androgen deprivation therapy (ADT) forms the cornerstone in prostate cancer (PCa) treatment. However, ADT also lowers skeletal muscle mass.

OBJECTIVE

To identify the impact of ADT with and without resistance exercise training on muscle fiber characteristics in PCa patients.

METHODS

Twenty-one PCa patients (72 ± 6 years) starting ADT were included. Tissue samples from the vastus lateralis muscle were assessed at baseline and after 20 weeks of usual care (n = 11) or resistance exercise training (n = 10). Type I and II muscle fiber distribution, fiber size, and myonuclear and capillary contents were determined by immunohistochemistry.

RESULTS

Significant decreases in type I (from 7401 ± 1183 to 6489 ± 1293 μm2, P < .05) and type II (from 6225 ± 1503 to 5014 ± 714 μm2, P < .05) muscle fiber size were observed in the usual care group. In addition, type I and type II individual capillary-to-fiber ratio (C/Fi) declined (-12% ± 12% and -20% ± 21%, respectively, P < .05). In contrast, significant increases in type I (from 6700 ± 1464 to 7772 ± 1319 μm2, P < .05) and type II (from 5248 ± 892 to 6302 ± 1385 μm2, P < .05) muscle fiber size were observed in the training group, accompanied by an increase in type I and type II muscle fiber myonuclear contents (+24% ± 33% and +21% ± 23%, respectively, P < .05) and type I C/Fi (+18% ± 14%, P < .05).

CONCLUSION

The onset of ADT is followed by a decline in both type I and type II muscle fiber size and capillarization in PCa patients. Resistance exercise training offsets the negative impact of ADT and increases type I and II muscle fiber size and type I muscle fiber capillarization in these patients.

Effects on Bone and Muscle upon Treadmill Interval Training in Hypogonadal Male Rats

Testosterone deficiency in males is linked to various pathological conditions, including muscle and bone loss. This study evaluated the potential of different training modalities to counteract these losses in hypogonadal male rats. A total of 54 male Wistar rats underwent either castration (ORX, n = 18) or sham castration (n = 18), with 18 castrated rats engaging in uphill, level, or downhill interval treadmill training. Analyses were conducted at 4, 8, and 12 weeks postsurgery. Muscle force of the soleus muscle, muscle tissue samples, and bone characteristics were analyzed. No significant differences were observed in cortical bone characteristics. Castrated rats experienced decreased trabecular bone mineral density compared to sham-operated rats. However, 12 weeks of training increased trabecular bone mineral density, with no significant differences among groups. Muscle force measurements revealed decreased tetanic force in castrated rats at week 12, while uphill and downhill interval training restored force to sham group levels and led to muscle hypertrophy compared to ORX animals. Linear regression analyses showed a positive correlation between bone biomechanical characteristics and muscle force. The findings suggest that running exercise can prevent bone loss in osteoporosis, with similar bone restoration effects observed across different training modalities.

Effects of Exercise Training in Patients with Lung Cancer during Chemotherapy Treatment

Background

Cancer is the second greatest cause of death and disability after cardiovascular disease.

Objective

To determine the effects of exercise training in patients with lung cancer during chemotherapy treatment.

Methods

A randomised clinical trial was conducted in Shaukat Khanum Memorial Cancer Hospital and Institute of Radiotherapy and Nuclear Medicine (IRNUM) Peshawar. A total of 40 participants were randomly divided into two groups: i) the Experimental group (EG, n = 20) and ii) Control group (CG, n = 20). Both groups received exercise training for 4 weeks, with five sessions per week. The EG received pulmonary rehabilitation and aerobic training. The CG received only pulmonary rehabilitation. Both groups were evaluated at baseline and after 6 weeks through Mindful Attention Awareness Scale (MAAS) Urdu version, Six Minute Walk Test (6MWT), digital spirometry, Borgs scale, Hospital Anxiety and Depression Scale (HADs) and Visual Analogue Scale (VAS).

Results

Both the EG and CG showed significant improvement in MAAS scores at post-study with a (P < 0.001). The scores of 6MWT were improved significantly in both groups after intervention with a (P = 0.001). The patient's anxiety scores were significantly improved in both groups after intervention with a (P < 0.001), while depression scores were also improved considerably between the two groups at post-level with a (P < 0.001). Regarding spirometry value, both groups showed significant improvement after intervention for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC (P < 0.001). Both groups show significant differences in patient pain intensity and dyspnea at post-level with P < 0.001.

Conclusion

This study concluded that pulmonary rehabilitation along with aerobic training can be more effective than pulmonary rehabilitation alone for patients with lung cancer during chemotherapy treatment.

Effects of Aerobic Exercise on Cardiorespiratory Fitness, Cardiovascular Risk Factors, and Patient-Reported Outcomes in Long-Term Breast Cancer Survivors: Protocol for a Randomized Controlled Trial

BACKGROUND

Anthracycline-based chemotherapy has been mainstay of adjuvant breast cancer therapy for decades. Although effective, anthracyclines place long-term breast cancer survivors at risk of late effects, such as reduced cardiorespiratory fitness and increased risk of cardiovascular disease. Previous research has shown beneficial effects of exercise training on cardiorespiratory fitness, but the effects of exercise on limiting factors for cardiorespiratory fitness, cardiovascular risk factors, and patient-reported outcomes in long-term survivors are less clear. Whether previous exposure to breast cancer therapy modulates the effects of exercise is also unknown.

OBJECTIVE

The primary aim of the CAUSE (Cardiovascular Survivors Exercise) trial is to examine the effect of aerobic exercise on cardiorespiratory fitness in anthracycline-treated long-term breast cancer survivors. Secondary aims are to examine effects of exercise training on limiting factors for cardiorespiratory fitness, cardiovascular risk factors, and patient-reported outcomes, and to compare baseline values and effects of exercise training between similar-aged women with and those without prior breast cancer. A third aim is to examine the 24-month postintervention effects of aerobic exercise on primary and secondary outcomes.

METHODS

The CAUSE trial is a 2-armed randomized controlled trial, where 140 long-term breast cancer survivors, 8-12 years post diagnosis, are assigned to a 5-month nonlinear aerobic exercise program with 3 weekly sessions or to standard care. Seventy similar-aged women with no history of cancer will undergo the same exercise program. Cardiorespiratory fitness measured as peak oxygen consumption (VO2peak), limiting factors for VO2peak (eg, cardiac function, pulmonary function, hemoglobin mass, blood volume, and skeletal muscle characteristics), cardiovascular risk factors (eg, hypertension, diabetes, dyslipidemia, obesity, physical activity level, and smoking status), and patient-reported outcomes (eg, body image, fatigue, mental health, and health-related quality of life) will be assessed at baseline, post intervention, and 24 months post intervention.

RESULTS

A total of 209 patients were included from October 2020 to August 2022, and postintervention assessments were completed in January 2023. The 24-month follow-up will be completed in February 2025.

CONCLUSIONS

The findings from the CAUSE trial will provide novel scientific understanding of the potential benefits of exercise training in long-term breast cancer survivors.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04307407; https://clinicaltrials.gov/ct2/show/NCT04307407.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/45244.

Dose-response relationship of resistance training for muscle morphology and strength in elderly cancer patients: A meta-analysis

Objective

To systematically evaluate the effects of resistance training (RT) on muscle strength and muscle hypertrophy in elderly cancer patients, and to provide dose-response relationships of RT variables that could improve muscle strength and morphology in elderly cancer patients.

Method

The Review Manager 5.3 was applied to analyze the 12 literatures (616 participants) through random or fixed effects model and global effect size to examine upper limb strength, lower extremity strength, and muscle hypertrophy. Sub-group analysis was made on five variables: the total number of repeated training times/week, load intensity, exercise frequency/week, exercise duration and gender. This study also examines the heterogeneity and publication bias.

Results

Twelve literatures (616 participants, 60-80 years) were included in meta-analysis. RT significantly increased the upper limb muscular strength (SMD = 0.51, 95% CI: 0.10-0.93; Z = 2.41; p = 0.02) and lower extremity strength (SMD = 0.48, 95% CI: 0.28-0.67; Z = 4.82; p < 0.00001), but had no significant effect on muscle morphology(SMD = 0.21, 95% CI: 0.01-0.42; Z = 1.88; p = 0.06). In subgroup analysis for lower extremity muscle strength in elderly male cancer patients, it was found that male intensity of 70-90%1RM, volume of 400-500 times per week, frequencies of 3 times per week, and session of 12-24 weeks, revealed the greatest effect. Funnel plot of the three studies shows that the results were reliable, and no publication bias was found.

Conclusion

RT had medium effects on improving muscle strength in elderly cancer patients, but it is not effective in improving muscle hypertrophy. In addition, when RT is performed, different training protocols can have an effect on the growth of muscle strength. Therefore, a lower extremity training protocol with a training intensity of 70-90% 1RM, a total of 400-500 repetitions per week, 3 times per week, and an exercise session of 12-24 weeks is most effective in improving lower extremity strength in elderly male cancer patients.

Feasibility of High-Intensity Resistance Training Sessions in Cancer Survivors

ABSTRACT

Schlüter, K, Schneider, J, Rosenberger, F, and Wiskemann, J. Feasibility of high-intensity resistance training sessions in cancer survivors. J Strength Cond Res 36(9): 2643-2652, 2022-Moderate-intensity resistance training (MIRT) is regarded as safe in cancer survivors (CS), but for high-intensity resistance training (HIRT), evidence is lacking. Hence, in the current exploratory analyses, single sessions of HIRT are compared with MIRT regarding safety and feasibility. Twenty-three of 24 included CS (14 breast and 10 prostate CS, 61.6 ± 9.5 years, body mass index 27.0 ± 4.3 kg·m -2 , 6-52 weeks after end of primary therapy) started a 12-week resistance training (RT) with a daily undulating periodization model including HIRT (90% of 1 repetition maximum [1RM]) and MIRT (67% 1RM) sessions. Parameters of safety (adverse events [AEs] and training-related pain), feasibility (physical and mental exhaustion, sensation of effort, enjoyment, and dropout rate), and adherence were assessed. An alpha level of 0.05 was applied for analyses. Nineteen of 23 training starters (83%) completed all sessions. Fourteen minor AEs occurred. A significantly higher increase for physical exhaustion appeared in HIRT ( p < 0.001). For 18% (HIRT) and 19% (MIRT) of the sessions, training-related pain was reported with no significant difference between intensities. In total, 34% of HIRT and 35% of MIRT sessions were perceived as overstraining or partly overstraining with no significant difference between intensities, but enjoyment (median and quartiles on a 1-7 scale) was high for both (HIRT = 5 [5;6] and MIRT = 5 [4,6]). Our analysis indicates that HIRT sessions do not differ from MIRT sessions concerning safety or feasibility, but training-related pain should be monitored. RT protocols incorporating high-intensity training loads can be applied safely in breast and prostate CS.

Muscle-to-tumor crosstalk: The effect of exercise-induced myokine on cancer progression

Physical exercise has gradually become a focus in cancer treatment due to its pronounced role in reducing cancer risk, enhancing therapeutic efficacy, and improving prognosis. In recent decades, skeletal muscles have been considered endocrine organs, exerting their biological functions via the endocrine, autocrine, and paracrine systems by secreting various types of myokines. The amount of myokines secreted varies depending on the intensity, type, and duration of exercise. Recent studies have shown that muscle-derived myokines are highly involved the effects of exercise on cancer. Multiple myokines, such as interleukin-6 (IL-6), oncostatin M (OSM), secreted protein acidic and rich in cysteine (SPARC), and irisin, directly mediate cancer progression by influencing the proliferation, apoptosis, stemness, drug resistance, metabolic reprogramming, and epithelial-mesenchymal transformation (EMT) of cancer cells. In addition, IL-6, interleukin-8 (IL-8), interleukin-15 (IL-15), brain-derived neurotrophic factor (BDNF), and irisin can improve obesity-induced inflammation by stimulating lipolysis of adipose tissues, promoting glucose uptake, and accelerating the browning of white fat. Furthermore, some myokines could regulate the tumor microenvironment, such as angiogenesis and the immune microenvironment. Cancer cachexia occurs in up to 80% of cancer patients and is responsible for 22%-30% of patient deaths. It is characterized by systemic inflammation and decreased muscle mass. Exercise-induced myokine production is important in regulating cancer cachexia. This review summarizes the roles and underlying mechanisms of myokines, such as IL-6, myostatin, IL-15, irisin, fibroblast growth factor 21 (FGF21) and musclin, in cancer cachexia. Through comprehensive analysis, we conclude that myokines are potential targets for inhibiting cancer progression and the associated cachexia.

Exercise Counteracts the Deleterious Effects of Cancer Cachexia

Simple Summary

This review provides an overview of the effects of exercise training on the major mechanisms related to cancer cachexia (CC). The review also discusses how cancer comorbidities can influence the ability of patients/animals with cancer to perform exercise training and what precautions should be taken when they exercise. The contribution of other factors, such as exercise modality and biological sex, to exercise effectiveness in ameliorating CC are also elaborated in the final sections. We provide meticulous evidence for how advantageous exercise training can be in patients/animals with CC at molecular and cellular levels. Finally, we emphasise what factors should be considered to optimise and personalise an exercise training program in CC.

Abstract

Cancer cachexia (CC) is a multifactorial syndrome characterised by unintentional loss of body weight and muscle mass in patients with cancer. The major hallmarks associated with CC development and progression include imbalanced protein turnover, inflammatory signalling, mitochondrial dysfunction and satellite cell dysregulation. So far, there is no effective treatment to counteract muscle wasting in patients with CC. Exercise training has been proposed as a potential therapeutic approach for CC. This review provides an overview of the effects of exercise training in CC-related mechanisms as well as how factors such as cancer comorbidities, exercise modality and biological sex can influence exercise effectiveness in CC. Evidence in mice and humans suggests exercise training combats all of the hallmarks of CC. Several exercise modalities induce beneficial adaptations in patients/animals with CC, but concurrent resistance and endurance training is considered the optimal type of exercise. In the case of cancer patients presenting comorbidities, exercise training should be performed only under specific guidelines and precautions to avoid adverse effects. Observational comparison of studies in CC using different biological sex shows exercise-induced adaptations are similar between male and female patients/animals with cancer, but further studies are needed to confirm this.

Does Androgen Deprivation for Prostate Cancer Affect Normal Adaptation to Resistance Exercise?

BACKGROUND

Loss of muscle mass and muscle function is a common side effect from androgen deprivation therapy (ADT) for prostate cancer (PCa). Here, we explored effects of heavy-load resistance training (RT) on lean body mass and muscle strength changes reported in randomized controlled trials (RCTs) among PCa patients on ADT and in healthy elderly men (HEM), by comparison of results in separate meta-analysis.

METHODS

RCTs were identified through databases and reference lists.

RESULTS

Seven RCTs in PCa patients (n = 449), and nine in HEM (n = 305) were included. The effects of RT in lean body mass change were similar among PCa patients (Standardized mean difference (SMD): 0.4, 95% CI: 0.2, 0.7) and HEM (SMD: 0.5, 95% CI: 0.2, 0.7). It is noteworthy that the within group changes showed different patterns in PCa patients (intervention: 0.2 kg; control: -0.6 kg) and HEM (intervention: 1.2 kg; control: 0.2 kg). The effects of RT on change in muscle strength (measured as 1 RM) were similar between PCa patients and HEM, both for lower body- (PCa: SMD: 1.9, 95% CI: 1.2, 2.5; HEM: SMD: 2.2, 95% CI: 1.0, 3.4), and for upper body exercises (PCa: SMD: 2.0, 95% CI: 1.3, 2.7; HEM: SMD: 1.9, 95% CI: 1.3, 2.6).

CONCLUSIONS

The effects of RT on lean body mass and 1 RM were similar in PCa patients on ADT and HEM, but the mechanism for the intervention effect might differ between groups. It seems that RT counteracts loss of lean body mass during ADT in PCa patients, as opposed to increasing lean body mass in HEM.

The effects of resistance training on muscular strength and hypertrophy in elderly cancer patients: A systematic review and meta-analysis

BACKGROUND

One of the most life-threatening comorbidities in elderly cancer patients is cancer cachexia, which is characterized by the ongoing loss of skeletal muscular strength and mass and is also associated with aging. There is a lack of recommendations for optimal resistance training (RT) for those patients. The purpose of this study was to systematically review and quantify the effects of RT on muscular strength and hypertrophy in elderly cancer patients.

METHODS

Five electronic databases were searched (until January 2020) for studies that met the following criteria: (i) cancer patients aged ≥60 years; (ii) structured and supervised RT intervention for ≥6 weeks; and (iii) measured muscular strength and/or hypertrophy.

RESULTS

Thirteen studies (717 participants, average age = 66 years) met the inclusion criteria. RT significantly increased muscular strength (mean effect size = 0.87, 95% confidence interval (95%CI): 0.43-1.32, p < 0.001) and did not significantly induce muscle hypertrophy (mean effect size = 0.09, 95%CI: -0.14 to 0.31, p = 0.45). In subgroup analyses for muscle strength, higher weekly frequency was significantly associated with larger effect size. Egger's test showed no significant publication bias for the 2 outcomes.

CONCLUSION

The results suggest that RT improves muscular strength but does not significantly induce muscle hypertrophy in elderly cancer patients.

Muscle wasting in cancer: opportunities and challenges for exercise in clinical cancer trials

BACKGROUND

Low muscle in cancer is associated with an increase in treatment-related toxicities and is a predictor of cancer-related and all-cause mortality. The mechanisms of cancer-related muscle loss are multifactorial, including anorexia, hypogonadism, anaemia, inflammation, malnutrition, and aberrations in skeletal muscle protein turnover and metabolism.

METHODS

In this narrative review, we summarise relevant literature to (i) review the factors influencing skeletal muscle mass regulation, (ii) provide an overview of how cancer/treatments negatively impact these, (iii) review factors beyond muscle signalling that can impact the ability to participate in and respond to an exercise intervention to counteract muscle loss in cancer, and (iv) provide perspectives on critical areas of future research.

RESULTS

Despite the well-known benefits of exercise, there remains a paucity of clinical evidence supporting the impact of exercise in cancer-related muscle loss. There are numerous challenges to reversing muscle loss with exercise in clinical cancer settings, ranging from the impact of cancer/treatments on the molecular regulation of muscle mass, to clinical challenges in responsiveness to an exercise intervention. For example, tumour-related/treatment-related factors (e.g. nausea, pain, anaemia, and neutropenia), presence of comorbidities (e.g. diabetes, arthritis, and chronic obstructive pulmonary disease), injuries, disease progression and bone metastases, concomitant medications (e.g., metformin), can negatively affect an individual's ability to exercise safely and limit subsequent adaptation.

CONCLUSIONS

This review identifies numerous gaps and oppportunities in the area of low muscle and muscle loss in cancer. Collaborative efforts between preclinical and clinical researchers are imperative to both understanding the mechanisms of atrophy, and develop appropriate therapeutic interventions.

Radiotherapy before or during androgen-deprivation therapy does not blunt the exercise-induced body composition protective effects in prostate cancer patients: A secondary analysis of two randomized controlled trials

BACKGROUND

Androgen deprivation therapy (ADT) contributes to lean mass loss and adiposity increases in prostate cancer patients. Radiotherapy during ADT might act synergistically and further worsen body composition. Previous investigations have shown that resistance training is an effective method of preserving body composition during ADT, however, most have not accounted for direct or indirect effects of other therapies, such as radiotherapy. Therefore, the purpose of this study was to examine training adaptations of the tissue composition in patients receiving radiation therapy (RT) prior or during ADT.

METHODS

Analyses were performed by combining data from two previous trials for a total of 131 prostate cancer patients who underwent a combination of resistance and aerobic exercise training (N = 70, age: 68.9 ± 6.6y, RT-before: 13%, RT-during: 14%) or usual care (N = 61, age: 67.5 ± 7.9y, RT-before: 16%, RT-during: 20%) for 3 months upon ADT onset. Whole-body lean mass (LM), fat percentage and appendicular LM were determined by dual energy x-ray absorptiometry, and lower-leg muscle area and density by peripheral computed tomography at baseline (onset of ADT) and at 3 months post-intervention. Covariates included RT prior and during the intervention, demographic characteristics, physical symptoms, and chronic conditions.

RESULTS

Radiotherapy before or during the intervention did not affect body composition. Only the usual care group experienced a significant decrease in whole-body LM (-994 ± 150 g, P < 0.001) and appendicular LM (-126 ± 19 g, P < 0.001), and an increase in whole-body fat percentage (1% ± 0.1%, P < 0.001). There was no change in lower-leg muscle area or density in either group.

CONCLUSION

We suggest that radiation prior to and during ADT does not interfere with the beneficial effects of exercise training on body composition in men with prostate cancer.

Effects of heavy-load resistance training during (neo-)adjuvant chemotherapy on muscle cellular outcomes in women with breast cancer

INTRODUCTION

(Neo-)adjuvant chemotherapy for breast cancer has a deleterious impact on muscle tissue resulting in reduced cardiorespiratory fitness, skeletal muscle mass and function. Physical exercise during treatment may counteract some of these negative effects. However, the effects of resistance training (RT) alone have never been explored. The present study aims to investigate if heavy-load RT during (neo-)adjuvant chemotherapy counteracts deleterious effects on skeletal muscle in women diagnosed with breast cancer. We hypothesize that (neo-)adjuvant treatment with chemotherapy will reduce muscle fiber size, impair mitochondrial function, and increase indicators of cellular stress and that RT during treatment will counteract these negative effects. We also hypothesize that RT during (neo-)adjuvant chemotherapy will increase muscle and blood levels of potential antitumor myokines and reduce treatment-related side effects on muscle strength and cardiorespiratory fitness.

METHODS

Fifty women recently diagnosed with breast cancer scheduled to start (neo-)adjuvant chemotherapy will be randomized to either randomized to either intervention group or to control group.The intervention group will perform supervised heavy-load RT twice a week over the course of chemotherapy (approximately 16-weeks) whereas the control group will be encouraged to continue with their usual activities. Muscle biopsies from m. vastus lateralis will be collected before the first cycle of chemotherapy (T0), after chemotherapy (T1), and 6 months later (T2) for assessment of muscle cellular outcomes. The primary outcome for this study is muscle fiber size. Secondary outcomes are: regulators of muscle fiber size and function, indicators of cellular stress and mitochondrial function, myokines with potential antitumor effects, muscle strength, and cardiorespiratory fitness.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Regional Ethical Review Board in Uppsala, Sweden (Dnr:2016/230/2). Results will be disseminated through presentations at scientific meetings, publications in peer-reviewed journals, social media, and patient organizations.

TRIAL REGISTRATION NUMBER

NCT04586517.

Effect of Periodized Resistance Training on Skeletal Muscle During Androgen Deprivation Therapy for Prostate Cancer: A Pilot Randomized Trial

PURPOSE

Prostate cancer survivors (PCS) receive androgen deprivation therapy (ADT) as treatment for recurrent cancer, yet ADT is associated with loss of skeletal muscle and physical function. Resistance training can counter both muscle and physical function loss; however, an understanding of the molecular responses of skeletal muscle to resistance training during ADT is still undefined. This sub-analysis of the original randomized, controlled pilot trial investigated effects of 12 weeks of periodized resistance training on mRNA expression of the anabolic genes IGF-1, myogenin, PGC-1α4 and the catabolic genes myostatin and MuRF-1 in skeletal muscle of PCS on ADT. Secondary aims investigated if changes in lean mass and physical function correlated with changes in mRNA expression.

METHODS

PCS on ADT (n = 17) were randomized to 12 weeks of supervised resistance training (EXE, n = 9) or home-based stretching (STRETCH, n = 8) 3 days per week. Outcomes were assessed at baseline and post-intervention. Muscle biopsies were analyzed by RT-PCR for mRNA expression. Body composition was assessed through dual-energy X-ray absorptiometry, and physical function through muscular strength, timed up and go, stair climb, and 400 m walk.

RESULTS

MuRF-1 mRNA expression was significantly greater in EXE compared to STRETCH post-intervention (P = .005). Change in MuRF-1 mRNA expression significantly correlated with improvements in strength and physical function (P < .05), while change in IGF-1 expression correlated with change in lean mass (P = .015).

CONCLUSION

Twelve weeks of resistance training increased mRNA expression of MuRF-1 in skeletal muscle of PCS on ADT. Elevations in resting mRNA expression of IGF-1, myogenin and PGC-1α4, and reduction in mRNA expression of myostatin that are typically expected following resistance training were not observed.

Effects of resistance exercise in prostate cancer patients : A systematic review update as of March 2020

Purpose

The aim of this systematic review is to provide an update on the effects of resistance exercise (RE) in patients with prostate cancer (PCa), with special attention to the effects on sexual health.

Methods

A systematic search of the literature was conducted in March 2020 using the databases PubMed, MEDLINE, EMBASE, SCOPUS and the Cochrane Library. Only randomized, controlled trials published after 31 December 2016 were included in this update. Additionally, articles from current and previous reviews were utilized to provide a brief summary of the effects on sexual health.

Results

A total of 10 articles met the inclusion criteria, of which 5 were identified as independent studies. The remaining five articles presented additional data for studies, which have already been included. The identified studies further strengthened the evidence for positive effects on muscle strength, body composition and physical function. Positive effects on bone mineral density were apparent only when RE was combined with impact training. One article reported an improvement in fatigue and health-related quality of life. Only one study examined the effects of RE in isolation and three articles indicated positive effects of exercise on sexual health.

Conclusion

Recent evidence supports the use of RE in PCa patient rehabilitation as a countermeasure for treatment side effects. Further research is necessary to ascertain the optimal delivery methods and illuminate the effects on health-related quality of life (HRQOL), fatigue and sexual health.

The effectiveness of lifestyle interventions to reduce side effects of androgen deprivation therapy for men with prostate cancer: a systematic review

PURPOSE

The aim of this review is to systematically review randomized controlled trials on lifestyle interventions on PCa patients undergoing androgen deprivation therapy.

METHODS

A literature search was conducted using the electronic databases Medline and PubMed. To be eligible, studies had to be randomized controlled trials (RCTs) that focused on side effects of ADT and lifestyle interventions to reduce side effects for men undergoing ADT with PCa. Lifestyle interventions were defined as interventions that included any dietary or behavioral components.

RESULTS

Twenty-nine trials were included. Most of them focused on exercise interventions, while some investigated the effect of dietary or behavioral interventions. The effect of different lifestyle influencing modalities aimed to improve on the adverse effects of ADT varied greatly.

CONCLUSIONS

It is not possible to draw one conclusion on the effect of exercise-based interventions, but noted on several adverse effects of ADT improvement. Further studies are necessary to develop personalized lifestyle interventions in order to mitigate the adverse effects.

Cancer Cachexia and Related Metabolic Dysfunction

Cancer cachexia is a complex multifactorial syndrome marked by a continuous depletion of skeletal muscle mass associated, in some cases, with a reduction in fat mass. It is irreversible by nutritional support alone and affects up to 74% of patients with cancer-dependent on the underlying type of cancer-and is associated with physical function impairment, reduced response to cancer-related therapy, and higher mortality. Organs, like muscle, adipose tissue, and liver, play an important role in the progression of cancer cachexia by exacerbating the pro- and anti-inflammatory response initially activated by the tumor and the immune system of the host. Moreover, this metabolic dysfunction is produced by alterations in glucose, lipids, and protein metabolism that, when maintained chronically, may lead to the loss of skeletal muscle and adipose tissue. Although a couple of drugs have yielded positive results in increasing lean body mass with limited impact on physical function, a single therapy has not lead to effective treatment of this condition. Therefore, a multimodal intervention, including pharmacological agents, nutritional support, and physical exercise, may be a reasonable approach for future studies to better understand and prevent the wasting of body compartments in patients with cancer cachexia.

The Adverse Effects of Androgen Deprivation Therapy in Prostate Cancer and the Benefits and Potential Anti-oncogenic Mechanisms of Progressive Resistance Training

Prostate cancer has the second highest incidence of all cancers amongst men worldwide. Androgen deprivation therapy (ADT) remains a common form of treatment. However, in reducing serum testosterone to castrate levels and rendering men hypogonadal, ADT contributes to a myriad of adverse effects which can affect prostate cancer prognosis. Physical activity is currently recommended as synergistic medicine in prostate cancer patients to alleviate the adverse effects of treatment. Progressive resistance training (PRT) is an anabolic exercise modality which may be of benefit in prostate cancer patients given its potency in maintaining and positively adapting skeletal muscle. However, currently, there is a scarcity of RCTs which have evaluated the use of isolated PRT in counteracting the adverse effects of prostate cancer treatment. Moreover, although physical activity in general has been found to reduce relapse rates and improve survival in prostate cancer, the precise anti-oncogenic effects of specific exercise modalities, including PRT, have not been fully established. Thus, the overall objective of this article is to provide a rationale for the in-depth investigation of PRT and its biological effects in men with prostate cancer on ADT. This will be achieved by (1) summarising the metabolic effects of ADT in patients with prostate cancer and its effect on prostate cancer progression and prognosis, (2) reviewing the existing evidence regarding the metabolic benefits of PRT in this cohort, (3) exploring the possible oncological pathways by which PRT can affect prostate cancer prognosis and progression and (4) outlining avenues for future research.

Growth Hormone(s), Testosterone, Insulin-Like Growth Factors, and Cortisol: Roles and Integration for Cellular Development and Growth With Exercise

Hormones are largely responsible for the integrated communication of several physiological systems responsible for modulating cellular growth and development. Although the specific hormonal influence must be considered within the context of the entire endocrine system and its relationship with other physiological systems, three key hormones are considered the "anabolic giants" in cellular growth and repair: testosterone, the growth hormone superfamily, and the insulin-like growth factor (IGF) superfamily. In addition to these anabolic hormones, glucocorticoids, mainly cortisol must also be considered because of their profound opposing influence on human skeletal muscle anabolism in many instances. This review presents emerging research on: (1) Testosterone signaling pathways, responses, and adaptations to resistance training; (2) Growth hormone: presents new complexity with exercise stress; (3) Current perspectives on IGF-I and physiological adaptations and complexity these hormones as related to training; and (4) Glucocorticoid roles in integrated communication for anabolic/catabolic signaling. Specifically, the review describes (1) Testosterone as the primary anabolic hormone, with an anabolic influence largely dictated primarily by genomic and possible non-genomic signaling, satellite cell activation, interaction with other anabolic signaling pathways, upregulation or downregulation of the androgen receptor, and potential roles in co-activators and transcriptional activity; (2) Differential influences of growth hormones depending on the "type" of the hormone being assayed and the magnitude of the physiological stress; (3) The exquisite regulation of IGF-1 by a family of binding proteins (IGFBPs 1-6), which can either stimulate or inhibit biological action depending on binding; and (4) Circadian patterning and newly discovered variants of glucocorticoid isoforms largely dictating glucocorticoid sensitivity and catabolic, muscle sparing, or pathological influence. The downstream integrated anabolic and catabolic mechanisms of these hormones not only affect the ability of skeletal muscle to generate force; they also have implications for pharmaceutical treatments, aging, and prevalent chronic conditions such as metabolic syndrome, insulin resistance, and hypertension. Thus, advances in our understanding of hormones that impact anabolic: catabolic processes have relevance for athletes and the general population, alike.

FATIGUE AND MUSCLE FUNCTION IN PROSTATE CANCER SURVIVORS RECEIVING DIFFERENT TREATMENT REGIMENS

ABSTRACT Introduction Prostate cancer is the most prevalent neoplastic disease in men. After diagnosis, different treatment regimens are proposed based on the stage of the cancer. These treatments affect physical and muscle function, quality of life, and prognosis differently. Objectives To assess fatigue, muscle strength, muscle thickness, and muscle quality in prostate cancer survivors undergoing androgen deprivation therapy (ADT). Methods Ten ADT patients, eight non-ADT patients and 18 healthy control subjects were enrolled in this study. Perceived fatigue was assessed through the 20-item Multidimensional Fatigue Inventory. Muscle thickness and quality (e.g., echo intensity) were assessed through B-mode ultrasound. Muscle strength and work capacity were assessed using an isokinetic dynamometer. The groups were compared with one-way ANOVA and Bonferroni adjustment. Results Muscle thickness, peak torque, and work capacity were lower in ADT than in the control group (CON) (p = 0.021; p = 0.005; p <0.001, respectively). ADT showed greater echo intensity than CON (p = 0.005) and N-ADT (p = 0.046). There were no differences between N-ADT and CON in terms of muscle thickness, peak torque, work capacity, and echo intensity (p >0.05). General fatigue was greater in both ADT (p = 0.030) and N-ADT (p = 0.047) compared to CON. Physical fatigue was greater in ADT than CON (p = 0.006). Conclusion ADT patients showed lower levels of muscle function and greater levels of perceived fatigue than healthy control subjects. It appears that muscle function remains lower in ADT patients, even several years after treatment initiation, although this does not apply to non-ADT patients. Level of evidence II; Diagnostic Studies - Investigating a Diagnostic Test.

Clinical and biological characterization of skeletal muscle tissue biopsies of surgical cancer patients

BACKGROUND

Researchers increasingly use intraoperative muscle biopsy to investigate mechanisms of skeletal muscle atrophy in patients with cancer. Muscles have been assessed for morphological, cellular, and biochemical features. The aim of this study was to conduct a state-of-the-science review of this literature and, secondly, to evaluate clinical and biological variation in biopsies of rectus abdominis (RA) muscle from a cohort of patients with malignancies.

METHODS

Literature was searched for reports on muscle biopsies from patients with a cancer diagnosis. Quality of reports and risk of bias were assessed. Data abstracted included patient characteristics and diagnoses, sample size, tissue collection and biobanking procedures, and results. A cohort of cancer patients (n = 190, 88% gastrointestinal malignancies), who underwent open abdominal surgery as part of their clinical care, consented to RA biopsy from the site of incision. Computed tomography (CT) scans were used to quantify total abdominal muscle and RA cross-sectional areas and radiodensity. Biopsies were assessed for muscle fibre area (μm² ), fibre types, myosin heavy chain isoforms, and expression of genes selected for their involvement in catabolic pathways of muscle.

RESULTS

Muscle biopsy occurred in 59 studies (total N = 1585 participants). RA was biopsied intraoperatively in 40 studies (67%), followed by quadriceps (26%; percutaneous biopsy) and other muscles (7%). Cancer site and stage, % of male participants, and age were highly variable between studies. Details regarding patient medical history and biopsy procedures were frequently absent. Lack of description of the population(s) sampled and low sample size contributed to low quality and risk of bias. Weight-losing cases were compared with weight stable cancer or healthy controls without considering a measure of muscle mass in 21 out of 44 studies. In the cohort of patients providing biopsy for this study, 78% of patients had preoperative CT scans and a high proportion (64%) met published criteria for sarcopenia. Fibre type distribution in RA was type I (46% ± 13), hybrid type I/IIA (1% ± 1), type IIA (36% ± 10), hybrid type IIA/D (15% ± 14), and type IID (2% ± 5). Sexual dimorphism was prominent in RA CT cross-sectional area, mean fibre cross-sectional area, and in expression of genes associated with muscle growth, apoptosis, and inflammation (P < 0.05). Medical history revealed multiple co-morbid conditions and medications.

CONCLUSIONS

Continued collaboration between researchers and cancer surgeons enables a more complete understanding of mechanisms of cancer-associated muscle atrophy. Standardization of biobanking practices, tissue manipulation, patient characterization, and classification will enhance the consistency, reliability, and comparability of future studies.

Exercise Training in Cancer Control and Treatment

Exercise training is playing an increasing role in cancer care, as accumulating evidence demonstrates that exercise may prevent cancer, control disease progression, interact with anti-cancer therapies, and improve physical functioning and psychosocial outcomes. In this overview article, we present the current state of the field of exercise oncology, which currently comprises of nearly 700 unique exercise intervention trials with more than 50,000 cancer patients. First, we summarize the range of these interventions with regard to diagnoses, clinical setting, timing, and type of intervention. Next, we provide a detailed discussion of the 292 trials, which have delivered structured exercise programs, outlining the impact of exercise training on cancer-specific, physiological, and psychosocial outcomes in the light of the challenges and physiological limitations cancer patients may experience. In summary, the safety and feasibility of exercise training is firmly established across the cancer continuum, and a wide range of beneficial effects on psychosocial and physiological outcomes are well documented. Many of these beneficial effects are linked to the general health-promoting properties of exercise. However, it is becoming increasing evident that exercise training can have direct effects on cancer and its treatment. This calls for future exercise oncology initiatives, which aim to target cancer-specific outcomes, and which are integrated into the concurrent cancer trajectory. Here, the field must bridge extensive knowledge of integrative exercise physiology with clinical oncology and cancer biology to provide a basis of individualized targeted approaches, which may place exercise training as an integrated component of standard cancer care. © 2019 American Physiological Society. Compr Physiol 9:165-205, 2019.

Exercise training during chemotherapy preserves skeletal muscle fiber area, capillarization, and mitochondrial content in patients with breast cancer

Exercise has been suggested to ameliorate the detrimental effects of chemotherapy on skeletal muscle. The aim of this study was to compare the effects of different exercise regimens with usual care on skeletal muscle morphology and mitochondrial markers in patients being treated with chemotherapy for breast cancer. Specifically, we compared moderate-intensity aerobic training combined with high-intensity interval training (AT-HIIT) and resistance training combined with high-intensity interval training (RT-HIIT) with usual care (UC). Resting skeletal muscle biopsies were obtained pre- and postintervention from 23 randomly selected women from the OptiTrain breast cancer trial who underwent RT-HIIT, AT-HIIT, or UC for 16 wk. Over the intervention, citrate synthase activity, muscle fiber cross-sectional area, capillaries per fiber, and myosin heavy chain isoform type I were reduced in UC, whereas RT-HIIT and AT-HIIT were able to counteract these declines. AT-HIIT promoted up-regulation of the electron transport chain protein levels vs. UC. RT-HIIT favored satellite cell count vs. UC and AT-HIIT. There was a significant association between change in citrate synthase activity and self-reported fatigue. AT-HIIT and RT-HIIT maintained or improved markers of skeletal muscle function compared with the declines found in the UC group, indicating a sustained trainability in addition to the preservation of skeletal muscle structural and metabolic characteristics during chemotherapy. These findings highlight the importance of supervised exercise programs for patients with breast cancer during chemotherapy.-Mijwel, S., Cardinale, D. A., Norrbom, J., Chapman, M., Ivarsson, N., Wengström, Y., Sundberg, C. J., Rundqvist, H. Exercise training during chemotherapy preserves skeletal muscle fiber area, capillarization, and mitochondrial content in patients with breast cancer.

Molecular Mechanisms Linking Exercise to Cancer Prevention and Treatment

The benefits of exercise training for cancer patients are becoming increasingly evident. Physical exercise has been shown to reduce cancer incidence and inhibit tumor growth. Here we provide the status of the current molecular understanding of the effect of exercise on cancer. We propose that exercise has a role in controlling cancer progression through a direct effect on tumor-intrinsic factors, interplay with whole-body exercise effects, alleviation of cancer-related adverse events, and improvement of anti-cancer treatment efficacy. These findings have wide-ranging societal implications, as this understanding may lead to changes in cancer treatment strategies.

Randomized study exploring the combination of radiotherapy with two types of acupuncture treatment (ROSETTA): study protocol for a randomized controlled trial

Background

Adverse effects such as fatigue, pain, erythema, nausea and vomiting are commonly known in patients undergoing irradiation (RT) alone or in combination with chemotherapy (RCHT). Patients suffering from these symptoms are limited in their daily life and their quality of life (QOL) is often reduced. As addressed in several trials, acupuncture can cause amelioration of these specific disorders. Especially for pain symptoms, several groups have shown efficacy of acupuncture. To what extent the difference between traditional acupuncture (verum acupuncture) and false acupuncture (sham acupuncture) is in reducing side effects and improvement of QOL is not clear.

Methods/design

ROSETTA is a prospective randomized phase II trial (version 1.0) to examine the efficacy of traditional acupuncture in patients with RT-related side effects. In the experimental (verum) arm (n = 37) an experienced acupuncture-trained person will treat dedicated acupuncture points. In the control (sham) arm (n = 37) sham acupuncture will be performed to provide a blinded comparison of results.

Discussion

This is the first randomized prospective trial to evaluate the effect of traditional acupuncture on RT-related side effects such as fatigue and QOL.

Trial registration

ClinicalTrials.gov, NCT02674646. Registered on 8 December 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2139-5) contains supplementary material, which is available to authorized users.

Effects of resistance exercise in prostate cancer patients: a meta-analysis

PURPOSE

The aim of the present meta-analysis was to quantify effects of resistance exercise (RE) on physical performance and function, body composition, health-related quality of life (HRQoL), and fatigue in patients with prostate cancer.

METHODS

Trial data were obtained from the databases PubMed, MEDLINE, EMBASE, SCOPUS, and the Cochrane Library as of inception to 31st of December 2016. Thirty-two trials with 1199 patients were included. Results that were measured by using the same assessment method in five or more of the original studies were pooled in a meta-analysis.

RESULTS

Pooled studies showed significant improvements of muscular strength in the upper and lower body (95% CI [2.52, 7.97] kg; p < 0.001 and 95% CI [10.51, 45.88] kg; p = 0.008, respectively) after RE. Furthermore, significant improvements were seen for body composition (body fat percentage 95% CI [-0.79, -0.53] %; p < 0.001; lean body mass 95% CI [0.15, 1.84] %; p = 0.028; trunk fat mass 95% CI [-0.73, -0.08] kg; p = 0.024). Additionally, the improvement of the 400-m walk time was significant (95% CI [-21.55, -14.65] s; p < 0.001). Concerning fatigue and HRQoL, there were not sufficient data for analysis.

CONCLUSIONS

RE seems to be a promising approach in order to counteract loss of muscle mass, muscle strength, and physical performance in patients suffering from prostate cancer and its treatment-related side effects. RE should play part in interdisciplinary cancer rehabilitation and care of this patient group. Nevertheless, further research should investigate RE further to determine which protocols are the most pragmatic, yet yielding best patient outcomes.

Lean body mass, muscle fibre size and muscle function in cancer patients during chemotherapy and 10 weeks exercise

Background: Chemotherapy can reduce muscle mass in cancer patients but the potential of exercise to ameliorate this are understudied, particularly at the myocellular level. The primary purpose was to investigate changes in lean body mass (LBM) and secondly single fibre cross-sectional area (CSA) in cancer patients during chemotherapy and in combination with 10 weeks of exercise. Methods: In a single-arm trial, patients adhered to chemotherapy for at least 4 weeks (control period) before 10 weeks of exercise adjunct to chemotherapy (exercise period). LBM (Dual Energy X-ray Absorptiometry) and single fibre CSA (muscle biopsies) were assessed at baseline, pre- and post-exercise.  Muscle strength, functional performance and aerobic capacity were also assessed. Results: Ten patients were included, however only six patients completed the protocol. LBM changed over time (p=0.013), but no significant changes were observed between specific time points. Numerically, LBM decreased by 0.3 kg (p=0.41, 95% CI: -1.1;0.5) from 41.3-41.0 kg, during the control period and increased by 0.7 kg (p=0.16, 95% CI: -0.6;2.0) from 40.4-41.1 kg during exercise. Muscle fibre CSA did not change significantly over time (p=0.13), but decreased numerically in the control period by 703 μm2 (p=0.20, 95% CI: -1877; 470) and increased by 846 μm2 (trend, p=0.08, 95% CI: -162; 1854) following exercise. Muscle strength and functional performance were unchanged during the control period but improved post-exercise. Conclusions:  Despite non-significant changes in muscle mass (due to small sample size), this study adds novel information on LBM and myocellular changes in cancer patients during chemotherapy and concurrent exercise.

The effect of strength training on muscle cellular stress in prostate cancer patients on ADT

BACKGROUND

Androgen deprivation therapy (ADT) for prostate cancer (PCa) is associated with several side effects, including loss of muscle mass. Muscle atrophy is associated with reduced mitochondrial function and increased muscle cellular stress that may be counteracted by strength training. Thus, the aim of this study was to investigate the effect of strength training on mitochondrial proteins and indicators of muscle cellular stress in PCa patients on ADT.

METHODS

Men diagnosed with locally advanced PCa receiving ADT were randomised to a strength training group (STG) (n=16) or a control group (CG) (n=15) for 16 weeks. Muscle biopsies were collected pre- and post-intervention from the vastus lateralis muscle, and analysed for mitochondrial proteins (citrate synthase, cytochrome c oxidase subunit IV (COXIV), HSP60) and indicators of muscle cellular stress (heat shock protein (HSP) 70, alpha B-crystallin, HSP27, free ubiquitin, and total ubiquitinated proteins) using Western blot and ELISA.

RESULTS

No significant intervention effects were observed in any of the mitochondrial proteins or indicators of muscle cellular stress. However, within-group analysis revealed that the level of HSP70 was reduced in the STG and a tendency towards a reduction in citrate synthase levels was observed in the CG. Levels of total ubiquitinated proteins were unchanged in both groups.

CONCLUSION

Although reduced HSP70 levels indicated reduced muscle cellular stress in the STG, the lack of an intervention effect precluded any clear conclusions.