The relationship between muscle mass and function in cancer cachexia: smoke and mirrors?

Cardiopulmonary exercise testing, computed tomography-derived body composition, systemic inflammation and survival after elective abdominal aortic aneurysm repair: A retrospective cohort study

BACKGROUND

Cardio-pulmonary exercise testing (CPEX) is selectively used before intervention for abdominal aortic aneurysm (AAA). Sarcopenia, a chronic condition defined by reduced skeletal muscle function and volume, can be assessed radiologically by computed tomography (CT)-derived body composition analysis (CT-BC), and is associated with systemic inflammation.

OBJECTIVE

The aim was to describe the association between CT-BC, CPEX, inflammation and survival in patients undergoing elective intervention for AAA.

SETTING

Patients were recruited retrospectively from a single, secondary-care centre-operative database. Cases undergoing elective endovascular aneurysm repair (EVAR) and open surgical repair (OSR) between 31 March 2015 and 25 June 2020 were included.

PATIENTS

There were 176 patients (130 EVAR, 46 OSR) available for analysis in the final study; median (interquartile range [IQR]) follow-up was 60.5 [27] months, and all completed a minimum of 2 years follow-up.

MAIN OUTCOME MEASURES

Preoperative CPEX tests were recorded. CT sarcopenia score [CT-SS, range 0 to 2, calculated based on normal/low SMI (0/1) and normal/low SMD (0/1)] assessed radiological sarcopenia. Preoperative modified Glasgow Prognostic score (mGPS) was used to assess systemic inflammation.

RESULTS

Mean [95% confidence interval (CI) survival in the CT-SS 0 vs. CT-SS 1 vs. CT-SS 2 subgroups was 80.1 (73.6 to 86.6) months vs. 70.3 (63.5 to 77.1) months vs. 63.8 (53.4 to 74.2) months] ( P  = 0.01). CT-SS was not associated with CPEX results ( P  > 0.05). Elevated CT-SS [hazard ratio (HR) 1.83, 95% CI, 1.16 to 2.89, P  < 0.01] was independently associated with increased hazard of long-term mortality; however, CPEX results were not ( P  > 0.05).

CONCLUSION

CPEX test results were not consistently associated with body composition and did not have significant prognostic value in patients undergoing elective treatment for AAA.

Body weight and composition endpoints in cancer cachexia clinical trials: Systematic Review 4 of the cachexia endpoints series

Significant variation exists in the outcomes used in cancer cachexia trials, including measures of body composition, which are often selected as primary or secondary endpoints. To date, there has been no review of the most commonly selected measures or their potential sensitivity to detect changes resulting from the interventions being examined. The aim of this systematic review is to assess the frequency and diversity of body composition measures that have been used in cancer cachexia trials. MEDLINE, Embase and Cochrane Library databases were systematically searched between January 1990 and June 2021. Eligible trials examined adults (≥18 years) who had received an intervention aiming to treat or attenuate the effects of cancer cachexia for >14 days. Trials were also of a prospective controlled design and included body weight or at least one anthropometric, bioelectrical or radiological endpoint pertaining to body composition, irrespective of the modality of intervention (e.g., pharmacological, nutritional, physical exercise and behavioural) or comparator. Trials with a sample size of <40 patients were excluded. Data extraction used Covidence software, and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. This review was prospectively registered (PROSPERO: CRD42022276710). A total of 84 clinical trials, comprising 13 016 patients, were eligible for inclusion. Non-small-cell lung cancer and pancreatic cancer were studied most frequently. The majority of trial interventions were pharmacological (52%) or nutritional (34%) in nature. The most frequently reported endpoints were assessments of body weight (68 trials, n = 11 561) followed by bioimpedance analysis (BIA)-based estimates (23 trials, n = 3140). Sixteen trials (n = 3052) included dual-energy X-ray absorptiometry (DEXA)-based endpoints, and computed tomography (CT) body composition was included in eight trials (n = 841). Discrepancies were evident when comparing the efficacy of interventions using BIA-based estimates of lean tissue mass against radiological assessment modalities. Body weight, BIA and DEXA-based endpoints have been most frequently used in cancer cachexia trials. Although the optimal endpoints cannot be determined from this review, body weight, alongside measurements from radiological body composition analysis, would seem appropriate. The choice of radiological modality is likely to be dependent on the trial setting, population and intervention in question. CT and magnetic resonance imaging, which have the ability to accurately discriminate tissue types, are likely to be more sensitive and provide greater detail. Endpoints are of particular importance when aligned with the intervention's mechanism of action and/or intended patient benefit.

Physical function endpoints in cancer cachexia clinical trials: Systematic Review 1 of the cachexia endpoints series

In cancer cachexia trials, measures of physical function are commonly used as endpoints. For drug trials to obtain regulatory approval, efficacy in physical function endpoints may be needed alongside other measures. However, it is not clear which physical function endpoints should be used. The aim of this systematic review was to assess the frequency and diversity of physical function endpoints in cancer cachexia trials. Following a comprehensive electronic literature search of MEDLINE, Embase and Cochrane (1990-2021), records were retrieved. Eligible trials met the following criteria: adults (≥18 years), controlled design, more than 40 participants, use of a cachexia intervention for more than 14 days and use of a physical function endpoint. Physical function measures were classified as an objective measure (hand grip strength [HGS], stair climb power [SCP], timed up and go [TUG] test, 6-min walking test [6MWT] and short physical performance battery [SPPB]), clinician assessment of function (Karnofsky Performance Status [KPS] or Eastern Cooperative Oncology Group-Performance Status [ECOG-PS]) or patient-reported outcomes (physical function subscale of the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaires [EORTC QLQ-C30 or C15]). Data extraction was performed using Covidence and followed PRISMA guidance (PROSPERO registration: CRD42022276710). A total of 5975 potential studies were examined and 71 were eligible. Pharmacological interventions were assessed in 38 trials (54%). Of these, 11 (29%, n = 1184) examined megestrol and 5 (13%, n = 1928) examined anamorelin; nutritional interventions were assessed in 21 trials (30%); and exercise-based interventions were assessed in 6 trials (8%). The remaining six trials (8%) assessed multimodal interventions. Among the objective measures of physical function (assessed as primary or secondary endpoints), HGS was most commonly examined (33 trials, n = 5081) and demonstrated a statistically significant finding in 12 (36%) trials (n = 2091). The 6MWT was assessed in 12 trials (n = 1074) and was statistically significant in 4 (33%) trials (n = 403), whereas SCP, TUG and SPPB were each assessed in 3 trials. KPS was more commonly assessed than the newer ECOG-PS (16 vs. 9 trials), and patient-reported EORTC QLQ-C30 physical function was reported in 25 trials. HGS is the most commonly used physical function endpoint in cancer cachexia clinical trials. However, heterogeneity in study design, populations, intervention and endpoint selection make it difficult to comment on the optimal endpoint and how to measure this. We offer several recommendations/considerations to improve the design of future clinical trials in cancer cachexia.

Measuring What Is Meaningful in Cancer Cachexia Clinical Trials: A Path Forward With Digital Measures of Real-World Physical Behavior

PURPOSE

The burden of cancer cachexia on patients' health-related quality of life, specifically their physical functioning, is well documented, but clinical trials thus far have failed to show meaningful improvement in physical functioning. The purpose of this review is to summarize existing methods of assessing physical function in cancer cachexia, outline a path forward for measuring what is meaningful to patients using digital measures derived from digital health technologies (DHTs), and discuss the current landscape of digital measures from the clinical and regulatory standpoint.

DESIGN

For this narrative review, peer-reviewed articles were searched on PubMed, clinical trials records were searched on clinicaltrials.gov, and records of digital measures submitted for regulatory qualification were searched on the US Food and Drug Administration's Drug Development Tool Qualification Program database.

RESULTS

There are gaps in assessing aspects of physical function that matter to patients. Existing assessment methods such as patient-reported outcomes and objective performance outcomes have limitations, including their episodic nature and burden to patients. DHTs such as wearable sensors can capture real-world physical behavior continuously, passively, and remotely, and may provide a more comprehensive picture of patients' everyday functioning. Recent regulatory submissions showcase potential clinical implementation of digital measures in various therapeutic areas.

CONCLUSION

Digital measures of real-world physical behavior present an opportunity to detect and demonstrate improvements in physical functioning in cancer cachexia, but evidence-based development is critical. For their use in clinical and regulatory decision making, studies demonstrating meaningfulness to patients as well as feasibility and validation are necessary.

Longitudinal characterisation of cachexia in patients undergoing surgical resection for cancer

PURPOSE OF REVIEW

The complexity of the cancer cachexia phenotype has undoubtedly hindered researchers' understanding of this devastating syndrome. The presence and magnitude of host-tumour interactions are rarely considered during clinical decision-making within the current staging paradigm. Furthermore, treatment options for those patients who are identified as suffering from cancer cachexia remain extremely limited.

RECENT FINDINGS

Previous attempts to characterise cachexia have largely focussed on individual surrogate disease markers, often studied across a limited timeframe. While the adverse prognostic value of clinical and biochemical features is evident, the relationships between these are less clear. Investigation of patients with earlier-stage disease could allow researchers to identify markers of cachexia that precede the refractory stage of the wasting process. Appreciation of the cachectic phenotype within 'curative' populations may aid our understanding of the syndrome's genesis and provide potential routes for prevention, rather than treatment.

SUMMARY

Holistic, longitudinal characterisation of cancer cachexia, across all at-risk and affected populations, is of vital importance for future research in the field. This paper presents the protocol for an observational study aiming to create a robust and holistic characterisation of surgical patients with, or at risk of, cancer cachexia.

EXT418, a novel long-acting ghrelin, mitigates Lewis lung carcinoma induced cachexia in mice

BACKGROUND

Ghrelin is a potential therapy for cachexia due to its orexigenic properties and anabolic effects on muscle and fat. However, its clinical use is limited by the short half-life of active (acylated) ghrelin (~11 min in humans). EXT418 is a novel long-acting, constitutively active ghrelin analog created by covalently linking it to a vitamin D derivative. Here, we evaluated the effects and mechanisms of action of EXT418 on Lewis lung carcinoma (LLC)-induced cachexia in mice.

METHODS

Male C57BL/6J mice (5- to 7-month-old) were implanted with 1 × 106 heat-killed (HK) or live LLC cells. When the tumour was palpable, mice were injected with vehicle (T + V) or EXT418 daily (T + 418 Daily, 0.25 mg/kg/day) or every other day (T + 418 EOD, 0.5 mg/kg/EOD) for up to 14 days, whereas HK-treated mice were given vehicle (HK + V). Subsets of T + 418 Daily or EOD-treated mice were pair-fed to the T + V group. Body composition and grip strength were evaluated before tumour implantation and at the end of the experiment. Molecular markers were probed in muscles upon termination.

RESULTS

In tumour-bearing mice, administration of EXT418 daily or EOD partially prevented weight loss (T + V vs. T + 418 Daily, P = 0.030; and vs. T + 418 EOD, P = 0.020). Similar effects were observed in whole body fat and lean body mass. Grip strength in tumour-bearing mice was improved by EXT418 daily (P = 0.010) or EOD (P = 0.008) administration compared with vehicle-treated mice. These effects of EXT418 on weight and grip strength were partially independent of food intake. EXT418 daily administration also improved type IIA (P = 0.015), IIB (P = 0.037) and IIX (P = 0.050) fibre cross-sectional area (CSA) in tibialis anterior (TA) and EXT418 EOD improved CSA of IIB fibres in red gastrocnemius (GAS; P = 0.005). In skeletal muscles, tumour-induced increases in atrogenes Fbxo32 and Trim63 were ameliorated by EXT418 treatments (TA and GAS/plantaris, PL), which were independent of food intake. EXT418 administration decreased expression of the mitophagy marker Bnip3 (GAS/PL; P ≤ 0.010). Similar effects of EXT418 EOD were observed in p62 (GAS/PL; P = 0.039). In addition, EXT418 treatments ameliorated the tumour-induced elevation in muscle Il6 transcript levels (TA and GAS/PL), independently of food intake. Il-6 transcript levels in adipose tissue and circulating IL-10 were elevated in response to the tumour but these increases were not significant with EXT418 administration. Tumour mass was not altered by EXT418.

CONCLUSIONS

EXT418 mitigates LLC-induced cachexia by attenuating skeletal muscle inflammation, proteolysis, and mitophagy, without affecting tumour mass and partially independent of food intake.

Clinical usefulness of the Patient-Generated Subjective Global Assessment and modified Glasgow Prognostic Score in decision making concerning the indication of enteral nutritional therapy in patients with incurable cancer receiving palliative care

OBJECTIVES

This study aimed to identify the clinical usefulness of assessing nutritional status using validated tools for the indication of enteral nutrition for patients with incurable cancer in palliative care.

METHODS

In this prospective cohort study, patients were assessed for nutritional risk using the Patient-Generated Subjective Global Assessment and for cancer cachexia (CC) using the modified Glasgow Prognostic Score upon enrollment and after ∼30 d. The outcome was stable or improved Karnofsky Performance Status. Logistic regression models were used, providing the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

A total of 180 patients participated. The only nutritional status parameter that was associated with function was CC. The less severe the CC, the more likely Karnofsky Performance Status was to remain stable or improve over 30 d (non-cachectic: OR = 1.95; 95% CI, 1.01-3.47; malnourished: OR = 1.06; 95% CI, 1.01-1.42). Furthermore, white skin color (OR = 1.79; 95% CI, 1.04-2.47), higher educational level (OR = 1.39; 95% CI, 1.13-2.78), and inadequate calorie intake (OR = 1.96; 95% CI, 1.02-2.81) were also associated with the outcome.

CONCLUSIONS

Using the modified Glasgow Prognostic Score to identify the existence and severity of CC, which is associated with function, has the potential to help clinical decision making concerning the indication of enteral nutrition in patients with incurable cancer receiving palliative care.

Imaging Techniques to Determine Degree of Sarcopenia and Systemic Inflammation in Advanced Renal Cell Carcinoma

PURPOSE OF REVIEW

The purpose of this review is to provide an up-to-date understanding regarding the literature on sarcopenia and inflammation as prognostic factors in the context of renal cell carcinoma (RCC).

RECENT FINDINGS

Sarcopenia is increasingly recognized as a prognostic factor in RCC. Emerging literature suggests monitoring quantity of muscle on successive imaging and examining muscle density may be additionally informative. Inflammation has prognostic ability in RCC and is also considered a key contributor to development and progression of both RCC and sarcopenia. Recent studies suggest these two prognostic factors together may provide additional prognostic ability when used in combination. Ongoing developments include quality control regarding sarcopenia research and imaging, improving understanding of muscle loss mechanisms, and enhancing clinical incorporation of sarcopenia via improving imaging analysis practicality (i.e., artificial intelligence) and feasible biomarkers. Sarcopenia and systemic inflammation are complementary prognostic factors for adverse outcomes in patients with RCC. Further study on high-quality sarcopenia assessment standardization and expedited sarcopenia assessment is desired for eventual routine clinical incorporation of these prognostic factors.

Muscle abnormalities in patients with liver cirrhosis and its effect on muscle function

OBJECTIVES

The progression of chronic liver disease is associated with metabolic alterations that compromise the patient's body composition and physical function. Muscle wasting often occurs with pathologic fat accumulation in the muscle (myosteatosis). Unfavorable changes in body composition frequently arise in conjunction with a decrease in muscle strength. These conditions are associated with worse prognoses. The aim of this study was to explore the associations between computed tomography (CT)-derived measures of muscle mass and muscle radiodensity (myosteatosis) and its correlation with muscle strength in patients with advanced chronic liver disease.

METHODS

This cross-sectional study was conducted between July 2016 and July 2017. CT images at the third lumbar vertebra level (L3) were analyzed, and skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD) were defined. Handgrip strength (HGS) was assessed by dynamometry. Correlations between CT-assessed body composition and HGS were tested. Multivariable linear regression was used to determine the factors associated with HGS.

RESULTS

We evaluated 118 patients with cirrhosis, of whom 64.4% were men. Of those evaluated, the mean age was 57.5 ± 8.5 y. Both SMI and SMD showed a positive correlation with muscle strength (r = 0.46 and 0.25, respectively); and age and Model for End-Stage Liver Disease (MELD)score showed the highest negative correlations (r = -0.37 and -0.34, respectively). In multivariable analyses, the presence of comorbidities (≥1), MELD score, and SMI were significantly associated with HGS.

CONCLUSIONS

Low muscle mass and clinical characteristics of disease severity may adversely affect muscle strength in patients with liver cirrhosis.

UBR2 targets myosin heavy chain IIb and IIx for degradation: Molecular mechanism essential for cancer-induced muscle wasting

Cancer cachexia is a lethal metabolic syndrome featuring muscle wasting with preferential loss of fast-twitching muscle mass through an undefined mechanism. Here, we show that cancer induces muscle wasting by selectively degrading myosin heavy chain (MHC) subtypes IIb and IIx through E3 ligase UBR2-mediated ubiquitylation. Induction of MHC loss and atrophy in C2C12 myotubes and mouse tibialis anterior (TA) by murine cancer cells required UBR2 up-regulation by cancer. Genetic gain or loss of UBR2 function inversely altered MHC level and muscle mass in TA of tumor-free mice. UBR2 selectively interacted with and ubiquitylated MHC-IIb and MHC-IIx through its substrate recognition and catalytic domain, respectively, in C2C12 myotubes. Elevation of UBR2 in muscle of tumor-bearing or free mice caused loss of MHC-IIb and MHC-IIx but not MHC-I and MHC-IIa or other myofibrillar proteins, including α-actin, troponin, tropomyosin, and tropomodulin. Muscle-specific knockout of UBR2 spared KPC tumor-bearing mice from losing MHC-IIb and MHC-IIx, fast-twitching muscle mass, cross-sectional area, and contractile force. The rectus abdominis (RA) muscle of patients with cachexia-prone cancers displayed a selective reduction of MHC-IIx in correlation with higher UBR2 levels. These data suggest that UBR2 is a regulator of MHC-IIb/IIx essential for cancer-induced muscle wasting, and that therapeutic interventions can be designed by blocking UBR2 up-regulation by cancer.

Effects of specialised nutritional interventions in patients with incurable cancer: a systematic review

Objective

To evaluate current evidence of the effect of specialised nutritional interventions on nutritional status, survival, quality of life and measures of functionality in patients with incurable cancer.

Methods

Systematic literature review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using PubMed/MEDLINE, EMBASE, Scopus, LILACS and Cochrane Library databases. Clinical studies that evaluated different specialised nutritional interventions, such as nutritional counselling, oral nutritional supplementation (ONS), enteral nutrition (EN) and parenteral nutrition (PN), were eligible. Only studies classified as being of high methodological quality (ie, low or moderate risk of bias) were included.

Results

A total of 22 studies reporting on 2448 patients were deemed eligible. Five types of specialised nutrition were observed: mixed (multimodal nature, ie, dietary counseling, ONS, physical activity and/or drugs) (n=12), ONS (n=5), PN (n=3), EN (n=1) and multidisciplinary team counselling (n=1). Benefits of any kind from the interventions were reported in 14 (63.6%) studies, mainly resulting from mixed intervention. Nutritional status improved in 12 (60.0%) of 20 studies and quality of life improved in eight (50.0%) of 16 studies. Few studies have evaluated the influence of nutritional interventions on survival and measure of functionality, and have not shown improvement in these outcomes.

Conclusion

Despite the limited evidence, specialised nutritional interventions can yield positive effects for patients with incurable cancer, mainly in their nutritional status and quality of life.

Therapeutic effects of androgens for cachexia

Cachexia is a complex wasting syndrome, accompanying a variety of end-stage chronic diseases, such as cancer, heart failure and human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS). It significantly affects patients' quality of life and survival. Multiple therapeutic approaches have been studied over time. However, despite promising results, no drug has been approved to date. In this review, we examine and discuss the available data on the therapeutic effects of androgens and selective androgen receptor modulators (SARMs) for cachexia.

Low muscle mass, low muscle function, and sarcopenia in the urban and rural elderly

Health outcomes of the elderly vary between rural and urban areas. Sarcopenia is diagnosed as loss of muscle strength or impaired physical performance, namely "low muscle function" and low muscle mass. Outcomes of low muscle mass and low muscle function are not equal. This study aimed to investigate the prevalence of low muscle mass, low muscle function, and sarcopenia in rural and urban populations and to determine whether regional differences were associated with each of these components. Participants aged ≥ 69 years (n = 2354) were recruited from three urban districts and one rural district in Korea. Low muscle mass was defined by appendicular lean mass using bioelectrical impedance analysis. Low muscle function was defined by handgrip strength and 5-chair stand test. Sarcopenia was defined as low muscle mass plus low muscle function. The prevalence of low muscle function (53.7% vs. 72.8%), and sarcopenia (16.3% vs. 24.4%) were higher in the rural elderly population. Rural residence was associated with low muscle function (OR 1.63; 95% CI 1.13-2.37, P = 0.009), but not with low muscle mass (OR 0.58; 95% CI 0.22-1.54, P = 0.271) or with sarcopenia (OR 1.13; 95% CI 0.63-2.00, P = 0.683). Interventions to detect and improve low muscle function in rural elderly population are needed.

REVOLUTION (Routine EValuatiOn of people LivIng with caNcer)-Protocol for a prospective characterisation study of patients with incurable cancer

Introduction

There is a pressing need for a holistic characterisation of people with incurable cancer. In this group, where quality of life and improvement of symptoms are therapeutic priorities, the physical and biochemical manifestations of cancer are often studied separately, giving an incomplete picture. In order to improve care, spur therapeutic innovation, provide meaningful endpoints for trials and set priorities for future research, work must be done to explore how the tumour influences the clinical phenotype. Characterisation of the host-tumour interaction may also provide information regarding prognosis, allowing appropriate planning of investigations, treatment and referral to palliative medicine services.

Methods

Routine EValuatiOn of people LivIng with caNcer (REVOLUTION) is a prospective observational study that aims to characterise people with incurable cancer around five key areas, namely body composition, physical activity, systemic inflammatory response, symptoms, and quality of life by developing a bio-repository. Participants will initially be recruited from a single centre in the UK and will have assessments of body composition (bio-impedance analysis [BIA] and computed tomography [CT]), assessment of physical activity using a physical activity monitor, measurement of simple markers of inflammation and plasma cytokine proteins and three symptom and quality of life questionnaires.

Discussion

This study aims to create a comprehensive biochemical and clinical characterisation of people with incurable cancer. Data in this study can be used to give a better understanding of the ‘symptom phenotype’ and quality of life determinants, development of a profile of the systemic inflammatory response and a detailed characterisation of body composition.

Muscle weakness as an additional criterion for grading sarcopenia-related prognosis in patients with cancer

Background

Low muscle strength has been pointed out as a key characteristic of sarcopenia, but the prognostic significance of muscle function next to reduced skeletal muscle mass (SMM) in patients with cancer has been scantily investigated.

Methods

Data on muscle strength by handgrip (HG) dynamometry and total‐body SMM estimated by bioelectrical impedance analysis (BIA) of Italian and German patients with cancer observed prospectively until death or censoring were analysed (N = 1076). Patients were stratified in four risk categories based on low HG (<10th percentiles of age and gender‐specific normative values) and low total‐body SMM according to SMM index cutoffs (<10.75 and <6.75 kg/m² in men and women, respectively).

Results

During a median follow‐up of 58 months [25th–75th percentile, 37–60], 566 patients had died. Patients presenting low HG in combination or not with low SMM were characterised by shorter median survival (12.7 vs. 27.2 months, respectively; p < 0.001) compared to those with low SMM/normal HG and normal SMM/normal HG (>60 months for both). After adjusting for sex, age, body mass index and percentage of weight loss, disease's stage, performance status and type of cancer, compared to reference category (normal HG and SMM; N = 210) the hazard ratios were: low SMM/normal HG (N = 342), 0.83 [95% confidence interval, CI, 0.67–1.02] (p = 0.073); normal SMM/low HG (N = 158), 1.19 [95% CI, 1.07–1.32] (p = 0.002); low SMM/low HG (N = 366), 1.39 [95% CI, 1.27–1.53] (p < 0.001).

Conclusions

Muscle weakness was found to be a more powerful predictor of survival than BIA‐estimated SMM and should be considered as an additional key feature of sarcopenia in patients with cancer.

Low muscle strength has been pointed out as a key characteristic of sarcopenia, but the prognostic significance of muscle function next to reduced skeletal muscle mass (SMM) in patients with cancer has been scantily investigated. Muscle weakness was found to be a more powerful predictor of survival than SMM and should be considered as additional key feature of sarcopenia in patients with cancer.

The Therapeutic Intervention of Sex Steroid Hormones for Sarcopenia

Sarcopenia, characterized by the excessive loss of skeletal muscle mass, strength, and function, is associated with the overall poor muscle performance status of the elderly, and occurs more frequently in those with chronic diseases. The causes of sarcopenia are multifactorial due to the inherent relationship between muscles and molecular mechanisms, such as mitochondrial function, inflammatory pathways, and circulating hormones. Age-related changes in sex steroid hormone concentrations, including testosterone, estrogen, progesterone, and their precursors and derivatives, are an important aspect of the pathogenesis of sarcopenia. In this review, we provide an understanding of the treatment of sarcopenia through the regulation of sex steroid hormones. The potential benefits and future research emphasis of each sex steroid hormone therapeutic intervention (testosterone, SARMs, estrogen, SERMs, DHEA, and progesterone) for sarcopenia are discussed. Enhanced understanding of the role of sex steroid hormones in the treatment for sarcopenia could lead to the development of hormone therapeutic approaches in combination with specific exercise and nutrition regimens.

Growth hormone secretagogue receptor-1a mediates ghrelin's effects on attenuating tumour-induced loss of muscle strength but not muscle mass

BACKGROUND

Ghrelin may ameliorate cancer cachexia (CC) by preventing anorexia, muscle, and fat loss. However, the mechanisms mediating these effects are not fully understood. This study characterizes the pathways involved in muscle mass and strength loss in the Lewis lung carcinoma (LLC)-induced cachexia model, and the effects of ghrelin in mice with or without its only known receptor: the growth hormone secretagogue receptor-1a ((GHSR-1a), Ghsr+/+ and Ghsr-/- ).

METHODS

Five to 7-month-old male C57BL/6J Ghsr+/+ and Ghsr-/- mice were inoculated with 1 × 106 heat-killed (HK) or live LLC cells (tumour implantation, TI). When tumours were palpable (7 days after TI), tumour-bearing mice were injected with vehicle (T + V) or ghrelin twice/day for 14 days (T + G, 0.8 mg/kg), while HK-treated mice were given vehicle (HK + V). Body weight and grip strength were evaluated before TI and at termination (21 days after TI). Hindlimb muscles were collected for analysis.

RESULTS

Less pronounced body weight (BW) loss (87.70 ± 0.98% vs. 83.92 ± 1.23%, percentage of baseline BW in tumour-bearing Ghsr+/+ vs. Ghsr-/- , P = 0.008), and lower upregulation of ubiquitin-proteasome system (UPS, MuRF1/Trim63, 5.71 ± 1.53-fold vs. 9.22 ± 1.94-fold-change from Ghsr+/+ HK + V in tumour-bearing Ghsr+/+ vs. Ghsr-/- , P = 0.036) and autophagy markers (Becn1, Atg5, Atg7, tumour-bearing Ghsr+/+  < Ghsr-/- , all P < 0.02) were found in T + V Ghsr+/+ vs. Ghsr-/- mice. Ghrelin attenuated LLC-induced UPS marker upregulation in both genotypes, [Trim63 was decreased from 5.71 ± 1.53-fold to 1.96 ± 0.47-fold in Ghsr+/+ (T + V vs. T + G: P = 0.032) and 9.22 ± 1.94-fold to 4.72 ± 1.06-fold in Ghsr-/- (T + V vs. T + G: P = 0.008)]. Only in Ghsr+/+ mice ghrelin ameliorated LLC-induced grip strength loss [improved from 89.24 ± 3.48% to 97.80 ± 2.31% of baseline (T + V vs. T + G: P = 0.042)], mitophagy markers [Bnip3 was decreased from 2.28 ± 0.56 to 1.38 ± 0.14-fold (T + V vs. T + G: P ≤ 0.05)], and impaired mitochondrial respiration [State 3u improved from 698.23 ± 73.96 to 934.37 ± 95.21 pmol/min (T + V vs. T + G: P ≤ 0.05)], whereas these markers were not improved by ghrelin Ghsr-/- . Compared with Ghsr+/+ , Ghsr-/- tumour-bearing mice also showed decreased response to ghrelin in BW [T + G-treated Ghsr+/+ vs. Ghsr -/- : 91.75 ± 1.05% vs. 86.18 ± 1.13% of baseline BW, P < 0.001)], gastrocnemius (T + G-treated Ghsr+/+ vs. Ghsr-/- : 96.9 ± 2.08% vs. 88.15 ± 1.78% of Ghsr+/+ HK + V, P < 0.001) and quadriceps muscle mass (T + G-treated Ghsr+/+ vs. Ghsr-/- : 96.12 ± 2.31% vs. 88.36 ± 1.94% of Ghsr+/+ HK + V, P = 0.01), and gastrocnemius type IIA (T + G-treated Ghsr+/+ vs. Ghsr-/- : 1250.49 ± 31.72 vs. 1017.62 ± 70.99 μm2 , P = 0.027) and IIB fibre cross-sectional area (T + G-treated Ghsr+/+ vs. Ghsr-/- : 2496.48 ± 116.88 vs. 2183.04 ± 103.43 μm2 , P = 0.024).

CONCLUSIONS

Growth hormone secretagogue receptor-1a mediates ghrelin's effects on attenuating LLC-induced weakness but not muscle mass loss by modulating the autophagy-lysosome pathway, mitophagy, and mitochondrial respiration.

Imaging modalities for diagnosis and monitoring of cancer cachexia

Cachexia, a multifactorial wasting syndrome, is highly prevalent among advanced-stage cancer patients. Unlike weight loss in healthy humans, the progressive loss of body weight in cancer cachexia primarily implicates lean body mass, caused by an aberrant metabolism and systemic inflammation. This may lead to disease aggravation, poorer quality of life, and increased mortality. Timely detection is, therefore, crucial, as is the careful monitoring of cancer progression, in an effort to improve management, facilitate individual treatment and minimize disease complications. A detailed analysis of body composition and tissue changes using imaging modalities—that is, computed tomography, magnetic resonance imaging, (¹⁸F) fluoro-2-deoxy-d-glucose (¹⁸FDG) PET and dual-energy X-ray absorptiometry—shows great premise for charting the course of cachexia. Quantitative and qualitative changes to adipose tissue, organs, and muscle compartments, particularly of the trunk and extremities, could present important biomarkers for phenotyping cachexia and determining its onset in patients. In this review, we present and compare the imaging techniques that have been used in the setting of cancer cachexia. Their individual limitations, drawbacks in the face of clinical routine care, and relevance in oncology are also discussed.

Body composition, physical function and quality of life in healthy men and across different stages of prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) for prostate cancer (PC) has detrimental effects on physical function and quality of life (QoL), but the addition of androgen receptor signalling inhibitors (ARSI) on these outcomes is unclear.

PURPOSE

To compare body composition, physical function, and QoL across progressive stages of PC and non-cancer controls (CON).

METHODS

In men with hormone sensitive PC (HSPC, n = 43) or metastatic castration-resistant PC (mCRPC, n = 22) or CON (n = 37), relative and absolute lean and fat mass, physical function (6 m walk, chair stands, timed up and go [TUG], stair climb), and QoL were determined.

RESULTS

Relative body composition differed amongst all groups, along with ~39% greater absolute fat mass in mCRPC vs. CON. TUG and chair stands were ~71% and ~33% slower in mCRPC compared to both CON and HSPC, whereas stair climb was ~29% and 6 m walk was ~18% slower in mCRPC vs. CON. Relative body composition was correlated with physical function (r = 0.259-0.385). Clinically relevant differences for mCRPC were observed for overall QoL and several subscales vs. CON, although body composition and physical function did not influence QoL.

CONCLUSIONS

PC progression is associated with deteriorations in body composition and physical function. As ADT length was similar between groups, ARSI use for mCRPC likely contributed in part to these changes. Given the difficulties of improving lean mass during ADT, interventions that reduce adiposity may lessen the side effects of hormone therapy.

The Effect of Wheel Exercise on Functional Indices of Cachexia in Tumor-bearing Mice

INTRODUCTION

Cancer-related fatigue and muscle wasting have received significant attention over the last few decades with the goal of establishing interventions that can improve cancer patient life quality and survival. Increased physical activity has shown to reduce cancer-associated fatigue and has been proposed as a promising therapeutic to attenuate cancer-induced wasting. However, significant gaps remain in our understanding of how physical activity affects the compositional and functional changes that initiate muscle wasting. The purpose of the current study was to determine the effect of wheel exercise on body composition and functional indices of cancer cachexia before the development of significant wasting.

METHODS

Thirteen-week-old male Apc (MIN) and C57BL/6 (B6) mice were given free wheel access (W) or a locked wheel (Sed) for 5 wk.

RESULTS

Wheel activity was reduced in the MIN compared with B6; however, wheel access increased complex II expression in isolated skeletal muscle mitochondria regardless of genotype. Wheel access had no effect on tumor burden or plasma interleukin-6 in the MIN. MIN-W increased body weight and lean mass compared with MIN-Sed, and there was a direct correlation between wheel distance and lean mass change. MIN-W increased grip strength and treadmill time to fatigue compared with MIN-Sed. Within MIN-W mice, skeletal muscle fatigability was only improved in high runners (>60 min·d).

CONCLUSIONS

Our results suggest that there were therapeutic benefits of increased activity related to body composition, behavior, and whole-body function that were not dependent on exercise duration; however, there was an exercise threshold needed to improve skeletal muscle fatigability in tumor-bearing mice. Interestingly, wheel access was able to improve compositional and functional outcomes without mitigating tumor number or size.

The prognostic impact of BIA-derived fat-free mass index in patients with cancer

BACKGROUND & AIMS

Reduced muscle mass represents one of the top ranked phenotypic criteria for malnutrition proposed by the Global Leadership Initiative on Malnutrition. Although height-indexed fat-free mass (FFMI) thresholds have been proposed as useful surrogate measures of reduced muscle mass, the independent prognostic value of BIA-derived FFMI by bioelectric impedance analysis (BIA) in patients with cancer still needs to be fully explored.

METHODS

Data on body mass index (BMI), 6-month percentage of weight loss (%WL), FFMI by BIA and quality of life (QoL by EORTC Quality of Life Questionnaire [EORTC QLQ-C30]) of Italian and German patients observed prospectively until death or censoring were used (N = 1217). Patients were stratified in 5 risk categories according to a robustly validated scoring system based on BMI and %WL. Low FFMI was defined as follows: men, <17 kg/m²; women, <15 kg/m².

RESULTS

Reduced FFMI was found in 234 patients (19.2%). After a median follow-up of 57 months [25th-75th, 31-60], 620 patients (50.9%) had died. The study detected differences in survival between patients presenting with and without reduced FFMI (14.0 months vs. 45.1 months; P < 0.001). The fully-adjusted hazard ratio of mortality for low FFMI was 1.46 [95%CI, 1.18-1.81] (P < 0.001). Low FFMI was also independently associated with reduced QoL: fully-adjusted odds ratio, 1.50 [95%CI, 1.00-2.25] (P = 0.050).

CONCLUSIONS

Reduced FFMI by BIA independently predicted survival and was associated with impaired QoL. Altered body composition should always be considered in all patients with cancer as additional phenotypic criterion of poor prognosis and BIA offers the possibility of multiple, noninvasive bedside assessments.

Power Comparisons and Clinical Meaning of Outcome Measures in Assessing Treatment Effect in Cancer Cachexia: Secondary Analysis From a Randomized Pilot Multimodal Intervention Trial

Background: New clinical trials in cancer cachexia are essential, and outcome measures with high responsiveness to detect meaningful changes are crucial. This secondary analysis from a multimodal intervention trial estimates sensitivity to change and between treatment effect sizes (ESs) of outcome measures associated with body composition, physical function, metabolism, and trial intervention.

Methods: The study was a multicenter, open-label, randomized pilot study investigating the feasibility of a 6-week multimodal intervention [exercise, non-steroidal anti-inflammatory drugs, and oral nutritional supplements containing polyunsaturated fatty acids (n−3 PUFAs)] vs. standard cancer care in non-operable non-small-cell lung cancer and advanced pancreatic cancer. Body composition measures from computerized tomography scans and circulating biomarkers were analyzed.

Results: Forty-six patients were randomized, and the analysis included 22 and 18 patients in the treatment and control groups, respectively. The between-group ESs were high for body weight (ES = 1.2, p < 0.001), small for body composition and physical function [handgrip strength (HGS)] measures (ES < 0.25), moderate to high for n-3 PUFAs and 25-hydroxyvitamin D (25-OH vitamin D) (ES range 0.64–1.37, p < 0.05 for all), and moderate for serum C-reactive protein (ES = 0.53, p = 0.12). Analysis within the multimodal treatment group showed high sensitivity to change for adiponectin (ES = 0.86, p = 0.001) and n-3 PUFAs (ES > 0.8, p < 0.05 for all) and moderate for 25-OH vitamin D (ES = 0.49, p = 0.03). In the control group, a moderate sensitivity to change for body weight (ES = −0.84, p = 0.002) and muscle mass (ES = −0.67, p = 0.016) and a high sensitivity to change for plasma levels of 25-OH vitamin D (ES = −0.88, p = 0.002) were found.

Conclusion: Demonstrating high sensitivity to change and between treatment ES and body composition measures, body weight still stands out as a clinical and relevant outcome measure in cancer cachexia. Body composition and physical function measures clearly are important to address but demand large sample sizes to detect treatment group differences.

Trial registration:ClinicalTrials.gov identifier: NCT01419145.

Computed tomography-derived body composition analysis in patients with advanced cancer: clinical utility and future research

PURPOSE OF REVIEW

With weight loss increasingly occurring against a background of obesity across a variety of advanced cancers, there has been increasing interest in computed tomography (CT)-derived body composition analysis. Various imaging software packages and thresholds are commonly in use in CT-derived body composition analysis. This review discusses the current research in field of body composition with emphasis on the information required for such measurements to be taken into routine clinical practice.

RECENT FINDINGS

CT is widely used for tumour staging in patients with cancer. Over the last decade, this imaging modality has been exploited to make measurements of body composition. Using a common landmark (L3) several different thresholds have been developed to stratify adipose and muscle tissue areas according to age, sex and BMI and their relationship with survival. A significant relationship between CT-derived body composition and clinical outcomes has been shown in different tumour types and geographical locations. However, there is considerable variation with methods, thresholds and muscle groups used for analysis. Therefore, there would appear to be a need to develop reliable methodology and population-specific reference ranges to guide clinical interpretation and enable routine clinical use.

SUMMARY

There has been an explosion of clinical research interest in CT-derived body composition analysis. Such body composition analysis provides important host phenotype information which has prognostic value. For CT-derived body composition to be fit for use in routine clinical practice, there is need for universally accepted terminology, software, muscle group selection, prognostic thresholds to standardize such body composition analysis.

The Impact of Immune Cells on the Skeletal Muscle Microenvironment During Cancer Cachexia

Progressive weight loss combined with skeletal muscle atrophy, termed cachexia, is a common comorbidity associated with cancer that results in adverse consequences for the patient related to decreased chemotherapy responsiveness and increased mortality. Cachexia's complexity has provided a barrier for developing successful therapies to prevent or treat the condition, since a large number of systemic disruptions that can regulate muscle mass are often present. Furthermore, considerable effort has focused on investigating how tumor derived factors and inflammatory mediators directly signal skeletal muscle to disrupt protein turnover regulation. Currently, there is developing appreciation for understanding how cancer alters skeletal muscle's complex microenvironment and the tightly regulated interactions between multiple cell types. Skeletal muscle microenvironment interactions have established functions in muscle response to regeneration from injury, growth, aging, overload-induced hypertrophy, and exercise. This review explores the growing body of evidence for immune cell modulation of the skeletal muscle microenvironment during cancer-induced muscle wasting. Emphasis is placed on the regulatory network that integrates physiological responses between immune cells with other muscle cell types including satellite cells, fibroblast cells, and endothelial cells to regulate myofiber size and plasticity. The overall goal of this review is to provide an understanding of how different cell types that constitute the muscle microenvironment and their signaling mediators contribute to cancer and chemotherapy-induced muscle wasting.

The relationship between computed tomography derived skeletal muscle index, psoas muscle index and clinical outcomes in patients with operable colorectal cancer

BACKGROUND

Computed tomography-based measures of body composition are emerging as important prognostic factors for patients with colorectal cancer (CRC). The aim of this study was to examine the relationship between total skeletal muscle index (SMI), psoas muscle index (PMI) and clinical outcomes in patients with operable CRC.

METHODS

A retrospective cohort study of prospectively maintained database at Glasgow Royal Infirmary. CT image at L3 was carried out to assess total skeletal and psoas muscle areas and these were normalized for height squared to calculate SMI and PMI respectively. Patients were classified into high and low groups using calculated optimal thresholds and their relationship to clinical outcomes was studied using logistic regression analysis.

RESULTS

Of the 1002 patients included, 55% were male, 50% had low SMI and 42% had low PMI. A moderate correlation was found between total skeletal muscle and psoas areas (r_s = 0.70, p < 0.001). On univariate analysis, low SMI was associated with length of hospital stay (OR, 1.47; 95% CI, 1.15-1.89, p = 0.002) and overall survival (HR, 2.29; 95% CI, 1.47-3.58, p < 0.001). On multivariate analysis, low SMI was independently associated with length of hospital stay (HR 1.32; 95% CI, 1.02-1.70, p < 0.05). On univariate analysis, low PMI was associated with length of hospital stay (OR, 1.34; 95% CI, 1.04-1.73, p < 0.05) and overall survival (OR, 1.43; 95% CI, 1.10-1.86 p < 0.01). On multivariate analysis, low PMI was not independently significant.

CONCLUSION

The present study shows that though both total skeletal muscle index and psoas muscle index were directly associated and had prognostic value, total skeletal muscle index had independent prognostic value in patients with operable CRC.

The Relationship between ECOG-PS, mGPS, BMI/WL Grade and Body Composition and Physical Function in Patients with Advanced Cancer

Cancer remains one of the leading causes of mortality worldwide and the associated reduction in physical function has a marked impact on both quality of life and survival. The aim of the present study was to examine the relationship between Eastern Cooperative Oncology Group-Performance status (ECOG-PS), modified Glasgow Prognostic Score (mGPS), Body Mass Index/ Weight Loss grade (BMI/WL grade), and Computerised Tomography (CT)-derived body composition measurement and physical function in patients with advanced cancer. Nine sites contributed prospective data on patient demographics, ECOG-PS, mGPS, physical function tests, and CT-derived body composition. Categorical variables were analysed using χ² test for linear-by-linear association, or χ² test for 2-by-2 tables. Associations were analysed using binary logistic regression. A total of 523 cancer patients (266 males, 257 females) were included in the final analysis and most had metastatic disease (83.2%). The median overall survival was 5.6 months. On multivariate binary logistic regression analysis, a high ECOG-PS remained independently associated with a low skeletal muscle index (p < 0.001), low skeletal muscle density (p < 0.05), and timed up and go test failure (p < 0.001). A high mGPS remained independently associated with a low skeletal muscle density (p < 0.05) and hand grip strength test failure (p < 0.01). A high BMI/WL grade remained independently associated with a low subcutaneous fat index (p < 0.05), low visceral obesity (p < 0.01), and low skeletal muscle density (p < 0.05). In conclusion, a high ECOG-PS and a high mGPS as outlined in the ECOG-PS/mGPS framework were consistently associated with poorer body composition and physical function in patients with advanced cancer.

Selective androgen receptor modulators: the future of androgen therapy?

Selective androgen receptor modulators (SARMs) are small molecule drugs that function as either androgen receptor (AR) agonists or antagonists. Variability in AR regulatory proteins in target tissues permits SARMs to selectively elicit anabolic benefits while eschewing the pitfalls of traditional androgen therapy. SARMs have few side effects and excellent oral and transdermal bioavailability and may, therefore, represent viable alternatives to current androgen therapies. SARMs have been studied as possible therapies for many conditions, including osteoporosis, Alzheimer’s disease, breast cancer, stress urinary incontinence (SUI), prostate cancer (PCa), benign prostatic hyperplasia (BPH), male contraception, hypogonadism, Duchenne muscular dystrophy (DMD), and sarcopenia/muscle wasting/cancer cachexia. While there are no indications for SARMs currently approved by the Food and Drug Administration (FDA), many potential applications are still being explored, and results are promising. In this review, we examine the literature assessing the use of SARMS for a number of indications.

Deterioration in Muscle Mass and Physical Function Differs According to Weight Loss History in Cancer Cachexia

Background: Muscle mass and physical function (PF) are common co-primary endpoints in cancer cachexia trials, but there is a lack of data on how these outcomes interact over time. The aim of this secondary analysis of data from a trial investigating multimodal intervention for cancer cachexia (ClinicalTrials.gov: NCT01419145) is to explore whether changes in muscle mass and PF are associated with weight loss and cachexia status at baseline. Methods: Secondary analysis was conducted using data from a phase II randomized controlled trial including 46 patients with stage III–IV non-small cell lung cancer (n = 26) or inoperable pancreatic cancer (n = 20) due to commence chemotherapy. Cachexia status at baseline was classified according to international consensus. Muscle mass (assessed using computed tomography (CT)) and PF outcomes, i.e., Karnofsky performance status (KPS), self-reported PF (self-PF), handgrip strength (HGS), 6-minute walk test (6MWT), and physical activity (PA), were measured at baseline and after six weeks. Results: When compared according to cachexia status at baseline, patients with no/pre-cachexia had a mean loss of muscle mass (−5.3 cm², p = 0.020) but no statistically significant change in PF outcomes. Patients with cachexia also lost muscle mass but to a lesser extent (−2.8 cm², p = 0.146), but demonstrated a statistically significant decline in PF; KPS (−3.8 points, p = 0.030), self-PF (−8.8 points, p = 0.027), and HGS (−2.7 kg, p = 0.026). Conclusions: Weight loss history and cachexia status at baseline are of importance if one aims to detect changes in PF outcomes in cancer cachexia trials. To improve the use of co-primary endpoints that include PF in future trials, outcomes that have the potential to detect change relative to weight loss should be investigated further.

Emerging Treatment Options For Cancer-Associated Cachexia: A Literature Review

Cachexia is a disease that has been recognized since antiquity; however, research in this area has recently increased. Promising new agents, including anamorelin hydrochloride, have been tested in large randomized controlled studies, and multidrug as well as multimodal approaches have been proposed as having the potential to improve outcomes in patients with cancer cachexia. However, standard treatment remains elusive. This review summarizes the current literature on treatment of cancer-associated cachexia, showing that there are challenges associated with conducting clinical trials in such patients. First, poor recruitment, retention, and compliance among cachectic patients cause research delays. Second, the lack of consensus regarding clinically meaningful endpoints impedes standardization of study designs and results. Further consideration is needed to identify the most suitable study design and endpoints, which can lead to the development of pharmacological and nonpharmacological interventions that improve patients’ prognosis and outcomes.

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A multicenter, open-label, single-arm study of anamorelin (ONO-7643) in advanced gastrointestinal cancer patients with cancer cachexia

Background

Cancer cachexia is characterized by weight loss and is associated with increased morbidity and mortality in patients with cancer. Anamorelin (ONO‐7643; ANAM) is a novel and selective ghrelin receptor agonist that improves appetite, lean body mass (LBM), body weight, and anorexia.

Methods

This multicenter, open‐label, single‐arm study investigated the efficacy and safety of 100 mg anamorelin in 50 Japanese patients with advanced and unresectable gastrointestinal (colorectal, gastric, or pancreatic) cancer. ANAM was administered once daily over 12 weeks. The primary endpoint was the proportion of patients that maintained or gained LBM over the course of the study. Secondary endpoints included changes in LBM, body weight, quality of life (QoL), and nutritional status biomarkers.

Results

The proportion of patients who responded to treatment was 63.3% (95% CI, 48.3%‐76.6%), with a least square mean ± SE change in LBM and body weight from baseline of 1.89 ± 0.36 kg and 1.41 ± 0.61 kg, respectively. Appetite‐related questions on the QoL questionnaire showed that ANAM improved appetite. Adverse events occurred in 79.6% of patients, and the most common treatment‐related adverse events were increased γ‐glutamyl transpeptidase (8.2%), diabetes mellitus (6.1%), hyperglycemia (6.1%), and prolonged QRS complex (6.1%).

Conclusions

ANAM improved anorexia and patients' nutritional status, resulting in rapid increases in LBM and body weight in patients with advanced gastrointestinal cancer who had cancer cachexia. ANAM treatment was well tolerated over 12 weeks. ANAM is a potential clinically beneficial pharmacotherapeutic option for patients with advanced gastrointestinal cancer who have cancer cachexia.

The receipt of 100 mg anamorelin increases lean body mass and improves symptoms of anorexia and nutritional status in patients with advanced gastrointestinal cancer who have cancer cachexia. Anamorelin is well tolerated in these patients.

Novel molecular targets of muscle wasting in cancer patients

PURPOSE OF REVIEW

Cancer-associated muscle wasting affects many patients and leads to reduced patient function, decreased quality of life and poor responses to surgical and oncological treatments. Despite advancements in the understanding of its pathophysiology, no current treatment or accepted strategy for successful management exists. In this review, we provide an update on potential novel therapeutic targets in cancer cachexia.

RECENT FINDINGS

Recent research has focused on molecular mechanisms underlying cancer-associated muscle wasting, allowing identification of potential therapeutic targets and the development of several promising drugs. However, due to the multifactorial and patient-specific pathogenesis of cachexia, the demonstration of a measurable and meaningful clinical effect in randomized controlled trials has proven difficult. Potential novel targets such as circulating macrophage inhibitory cytokine 1/growth differentiation factor 15 and ZRT/IRT-like protein 14 have shown relevance in animal models, but their therapeutic manipulation has yet to be translated to patients. Increasing evidence has suggested that a single therapy may not be successful and a targeted, multimodal approach is required.

SUMMARY

The management of cancer-associated muscle wasting is complex. Future clinical trials should focus on early multimodal therapeutic interventions involving targeted therapies, with careful deliberation of chosen nutritional and functional outcomes.

The regulation of skeletal muscle fatigability and mitochondrial function by chronically elevated interleukin-6

NEW FINDINGS

What is the central question of this study? Interleukin-6 has been associated with muscle mass and metabolism in both physiological and pathological conditions. A causal role for interleukin-6 in the induction of fatigue and disruption of mitochondrial function has not been determined. What is the main finding and its importance? We demonstrate that chronically elevated interleukin-6 increased skeletal muscle fatigability and disrupted mitochondrial content and function independent of changes in fibre type and mass.

ABSTRACT

Interleukin-6 (IL-6) can initiate intracellular signalling in skeletal muscle by binding to the IL-6-receptor and interacting with the transmembrane gp130 protein. Circulating IL-6 has established effects on skeletal muscle mass and metabolism in both physiological and pathological conditions. However, the effects of circulating IL-6 on skeletal muscle function are not well understood. The purpose of this study was to determine whether chronically elevated systemic IL-6 was sufficient to disrupt skeletal muscle force, fatigue and mitochondrial function. Additionally, we examined the role of muscle gp130 signalling during overexpression of IL-6. Systemic IL-6 overexpression for 2 weeks was achieved by electroporation of an IL-6 overexpression plasmid or empty vector into the quadriceps of either C57BL/6 (WT) or skeletal muscle gp130 knockout (KO) male mice. Tibialis anterior muscle in situ functional properties and mitochondrial respiration were determined. Interleukin-6 accelerated in situ skeletal muscle fatigue in the WT, with a 18.5% reduction in force within 90 s of repeated submaximal contractions and a 7% reduction in maximal tetanic force after 5 min. There was no difference between fatigue in the KO and KO+IL-6. Interleukin-6 reduced WT muscle mitochondrial respiratory control ratio by 36% and cytochrome c oxidase activity by 42%. Interleukin-6 had no effect on either KO respiratory control ratio or cytochrome c oxidase activity. Interleukin-6 also had no effect on body weight, muscle mass or tetanic force in either genotype. These results provide evidence that 2 weeks of elevated systemic IL-6 is sufficient to increase skeletal muscle fatigability and decrease muscle mitochondrial content and function, and these effects require muscle gp130 signalling.