Showing papers in "Journal of Cachexia, Sarcopenia and Muscle in 2018"

Pitfalls in the measurement of muscle mass: a need for a reference standard

Abstract: BACKGROUND: All proposed definitions of sarcopenia include the measurement of muscle mass, but the techniques and threshold values used vary. Indeed, the literature does not establish consensus on the best technique for measuring lean body mass. Thus, the objective measurement of sarcopenia is hampered by limitations intrinsic to assessment tools. The aim of this study was to review the methods to assess muscle mass and to reach consensus on the development of a reference standard. METHODS: Literature reviews were performed by members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis working group on frailty and sarcopenia. Face-to-face meetings were organized for the whole group to make amendments and discuss further recommendations. RESULTS: A wide range of techniques can be used to assess muscle mass. Cost, availability, and ease of use can determine whether the techniques are better suited to clinical practice or are more useful for research. No one technique subserves all requirements but dual energy X-ray absorptiometry could be considered as a reference standard (but not a gold standard) for measuring muscle lean body mass. CONCLUSIONS: Based on the feasibility, accuracy, safety, and low cost, dual energy X-ray absorptiometry can be considered as the reference standard for measuring muscle mass.

Skeletal muscle performance and ageing

Abstract: The world population is ageing rapidly. As society ages, the incidence of physical limitations is dramatically increasing, which reduces the quality of life and increases healthcare expenditures. In western society, ~30% of the population over 55 years is confronted with moderate or severe physical limitations. These physical limitations increase the risk of falls, institutionalization, co-morbidity, and premature death. An important cause of physical limitations is the age-related loss of skeletal muscle mass, also referred to as sarcopenia. Emerging evidence, however, clearly shows that the decline in skeletal muscle mass is not the sole contributor to the decline in physical performance. For instance, the loss of muscle strength is also a strong contributor to reduced physical performance in the elderly. In addition, there is ample data to suggest that motor coordination, excitation-contraction coupling, skeletal integrity, and other factors related to the nervous, muscular, and skeletal systems are critically important for physical performance in the elderly. To better understand the loss of skeletal muscle performance with ageing, we aim to provide a broad overview on the underlying mechanisms associated with elderly skeletal muscle performance. We start with a system level discussion and continue with a discussion on the influence of lifestyle, biological, and psychosocial factors on elderly skeletal muscle performance. Developing a broad understanding of the many factors affecting elderly skeletal muscle performance has major implications for scientists, clinicians, and health professionals who are developing therapeutic interventions aiming to enhance muscle function and/or prevent mobility and physical limitations and, as such, support healthy ageing.

Loss of skeletal muscle during systemic chemotherapy is prognostic of poor survival in patients with foregut cancer.

Abstract: Background Malnutrition, weight loss, and muscle wasting are common in patients with foregut cancers (oesophagus, stomach, pancreas, liver, and bile ducts) and are associated with adverse clinical outcomes. However, little is known about the changes in body composition that occur in these patients during chemotherapy and its impacts clinical outcomes. Patients and methods A prospective study of adult foregut cancer patients undergoing chemotherapy between 2012 and 2016 was conducted. Computed tomography images were evaluated for cross-sectional skeletal muscle area (SMA) and adipose tissue area (ATA) at two time points [interval 118 days (IQR 92-58 days)]. Longitudinal changes in SMA and ATA were examined using paired t-tests. Sarcopenia and low muscle attenuation (MA) were defined using published cut-points. Cox proportional hazards models were used to estimate mortality hazard ratios for key predictors. Results A total of 225 foregut cancer patients were included (67% male, median age 66 years). At baseline, 40% were sarcopenic, 49% had low MA, and 62% had cancer cachexia. Longitudinal analysis (n = 163) revealed significant reductions in SMA [-6.1 cm2 (3.9%)/100 days, P 6.0%/100 days (highest fourth) independently predicted overall survival in patients receiving palliative chemotherapy [hazard ratio: 2.66, (95% CI: 1.42 to 4.97), P = 0.002]. Conclusions Patients with foregut cancers, particularly those treated with neoadjuvant chemotherapy, experience significant losses of muscle during chemotherapy. A high level of SMA loss is prognostic of reduced survival in patients treated with palliative chemotherapy. Multimodal interventions to stabilize or increase muscle mass and influence outcome warrant further investigation.

A newly identified lncRNA MAR1 acts as a miR‐487b sponge to promote skeletal muscle differentiation and regeneration

Abstract: Background Skeletal muscle atrophy induced by either aging (sarcopenia) or mechanical unloading is associated with serious health consequences. Long non-coding RNAs (lncRNAs) are implicated as important regulators in numerous physiological and pathological processes. Methods Microarray analysis was performed to identify the differentially expressed lncRNAs in skeletal muscle between adult and aged mice. The most decreased lncRNA in aged skeletal muscle was identified. The C2C12 mouse myoblast cells were used to assess the biological function of the lncRNA in vitro. The target microRNA of lncRNA and the target protein of microRNA were predicted by bioinformatics analysis and validated in vitro. Furthermore, the biology function of the lncRNA in vivo was investigated by local overexpression or knockdown the lncRNA in skeletal muscle. The therapeutic effect of the lncRNA overexpression in age-related or mechanical unloading-induced muscle atrophy was also evaluated. Results We identified a novel lncRNA (muscle anabolic regulator 1, MAR1) which was highly expressed in mice skeletal muscle and positively correlated with muscle differentiation and growth in vitro and in vivo. We predicted and validated that microRNA-487b (miR-487b) was a direct target of MAR1. We also predicted and validated that Wnt5a, an important regulator during myogenesis, was a target of miR-487b in C2C12 cells. Our findings further demonstrated that enforced MAR1 expression in myoblasts led to derepression of Wnt5a. Moreover, MAR1 promoted skeletal muscle mass/strength and Wnt5a protein level in mice. Enforced MAR1 expression in mice attenuated muscle atrophy induced by either aging or unloading. Conclusions The newly identified lncRNA MAR1 acts as a miR-487b sponge to regulate Wnt5a protein, resulting in promoting muscle differentiation and regeneration. MAR1 could be a novel therapeutic target for treating muscle atrophy induced by either aging or mechanical unloading.

Low‐protein diet for conservative management of chronic kidney disease: a systematic review and meta‐analysis of controlled trials

Abstract: Author(s): Rhee, Connie M; Ahmadi, Seyed-Foad; Kovesdy, Csaba P; Kalantar-Zadeh, Kamyar | Abstract: BackgroundRecent data pose the question whether conservative management of chronic kidney disease (CKD) by means of a low-protein diet can be a safe and effective means to avoid or defer transition to dialysis therapy without causing protein-energy wasting or cachexia. We aimed to systematically review and meta-analyse the controlled clinical trials with adequate participants in each trial, providing rigorous contemporary evidence of the impact of a low-protein diet in the management of uraemia and its complications in patients with CKD.MethodsWe searched MEDLINE (PubMed) and other sources for controlled trials on CKD to compare clinical management of CKD patients under various levels of dietary protein intake or to compare restricted protein intake with other interventions. Studies with similar patients, interventions, and outcomes were included in the meta-analyses.ResultsWe identified 16 controlled trials of low-protein diet in CKD that met the stringent qualification criteria including having 30 or more participants. Compared with diets with protein intake of g0.8ng/kg/day, diets with restricted protein intake (l0.8ng/kg/day) were associated with higher serum bicarbonate levels, lower phosphorus levels, lower azotemia, lower rates of progression to end-stage renal disease, and a trend towards lower rates of all-cause death. In addition, very-low-protein diets (protein intake l0.4ng/kg/day) were associated with greater preservation of kidney function and reduction in the rate of progression to end-stage renal disease. Safety and adherence to a low-protein diet was not inferior to a normal protein diet, and there was no difference in the rate of malnutrition or protein-energy wasting.ConclusionsIn this pooled analysis of moderate-size controlled trials, a low-protein diet appears to enhance the conservative management of non-dialysis-dependent CKD and may be considered as a potential option for CKD patients who wish to avoid or defer dialysis initiation and to slow down the progression of CKD, while the risk of protein-energy wasting and cachexia remains minimal.

Sarcopenia is negatively associated with long-term outcomes in locally advanced rectal cancer.

Abstract: Background The association of sarcopenia and visceral obesity to treatment outcome is not clear for locally advanced rectal cancer. This study evaluates the influence of skeletal muscle and visceral fat on short-term and long-term outcomes in locally advanced rectal cancer patients treated with neoadjuvant chemoradiation therapy followed by curative resection. Methods A total of 188 patients with locally advanced cancer were included between January 2009 and December 2013. Neoadjuvant chemoradiotherapy was followed by curative resection. Sarcopenia and visceral obesity were identified in initial staging CT by measuring the muscle and visceral fat area at the third lumbar vertebra level. Results Among the 188 included patients, 74 (39.4%) patients were sarcopenic and 97 (51.6%) patients were viscerally obese. Sarcopenia and high levels of preoperative carcinoembryonic antigen were significant prognostic factors for overall survival (P = 0.013, 0.014, respectively) in the Cox regression multivariate analysis. Visceral obesity was not associated with overall survival; however, it did tend to shorten disease-free survival (P = 0.079). Conclusions Sarcopenia is negatively associated with overall survival in locally advanced rectal cancer patients who underwent neoadjuvant chemoradiation therapy and curative resection. Visceral obesity tended to shorten disease-free survival. Future studies should be directed to optimize patient conditions according to body composition status.

Systematic review and meta-analysis of cannabinoids in palliative medicine.

Abstract: We provide a systematic review and meta-analysis on the efficacy, tolerability, and safety of cannabinoids in palliative medicine. The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PsycINFO, PubMed, Scopus, and http://clinicaltrials.gov, and a selection of cancer journals were searched up until 15th of March 2017. Of the 108 screened studies, nine studies with a total of 1561 participants were included. Overall, the nine studies were at moderate risk of bias. The quality of evidence comparing cannabinoids with placebo was rated according to Grading of Recommendations Assessment, Development, and Evaluation as low or very low because of indirectness, imprecision, and potential reporting bias. In cancer patients, there were no significant differences between cannabinoids and placebo for improving caloric intake (standardized mean differences [SMD]: 0.2 95% confidence interval [CI]: [-0.66, 1.06] P = 0.65), appetite (SMD: 0.81 95% CI: [-1.14, 2.75]; P = 0.42), nausea/vomiting (SMD: 0.21 [-0.10, 0.52] P = 0.19), >30% decrease in pain (risk differences [RD]: 0.07 95% CI: [-0.01, 0.16]; P = 0.07), or sleep problems (SMD: -0.09 95% CI: [-0.62, 0.43] P = 0.72). In human immunodeficiency virus (HIV) patients, cannabinoids were superior to placebo for weight gain (SMD: 0.57 [0.22; 0.92]; P = 0.001) and appetite (SMD: 0.57 [0.11; 1.03]; P = 0.02) but not for nausea/vomiting (SMD: 0.20 [-0.15, 0.54]; P = 0.26). Regarding side effects in cancer patients, there were no differences between cannabinoids and placebo in symptoms of dizziness (RD: 0.03 [-0.02; 0.08]; P = 0.23) or poor mental health (RD: -0.01 [-0.04; 0.03]; P = 0.69), whereas in HIV patients, there was a significant increase in mental health symptoms (RD: 0.05 [0.00; 0.11]; P = 0.05). Tolerability (measured by the number of withdrawals because of adverse events) did not differ significantly in cancer (RD: 1.15 [0.80; 1.66]; P = 0.46) and HIV patients (RD: 1.87 [0.60; 5.84]; P = 0.28). Safety did not differ in cancer (RD: 1.12 [0.86; 1.46]; P = 0.39) or HIV patients (4.51 [0.54; 37.45]; P = 0.32) although there was large uncertainty about the latter reflected in the width of the CI. In one moderate quality study of 469 cancer patients with cancer-associated anorexia, megestrol was superior to cannabinoids in improving appetite, producing >10% weight gain and tolerability. In another study comparing megestrol to dronabinol in HIV patients, megestrol treatment led to higher weight gain without any differences in tolerability and safety. We found no convincing, unbiased, high quality evidence suggesting that cannabinoids are of value for anorexia or cachexia in cancer or HIV patients.

The evolution of body composition in oncology—epidemiology, clinical trials, and the future of patient care: facts and numbers

Abstract: There is growing interest from the oncology community to understand how body composition measures can be used to improve the delivery of clinical care for the 18.1 million individuals diagnosed with cancer annually. Methods that distinguish muscle from subcutaneous and visceral adipose tissue, such as computed tomography (CT), may offer new insights of important risk factors and improved prognostication of outcomes over alternative measures such as body mass index. In a meta-analysis of 38 studies, low muscle area assessed from clinically acquired CT was observed in 27.7% of patients with cancer and associated with poorer overall survival [hazard ratio: 1.44, 95% CI: 1.32-1.56]. Therapeutic interventions such as lifestyle and pharmacotherapy that modify all aspects of body composition and reduce the incidence of poor clinical outcomes are needed in patients with cancer. In a meta-analysis of six randomized trials, resistance training exercise increased lean body mass assessed from dual-energy X-ray absorptiometry [mean difference (MD): +1.07 kg, 95% CI: 0.76-1.37; P < 0.001] and walking distance [MD: +143 m, 95% CI: 70-216; P < 0.001] compared with usual care control in patients with non-metastatic cancer. In a meta-analysis of five randomized trials, anamorelin (a ghrelin agonist) significantly increased lean body mass [MD: +1.10 kg, 95% CI: 0.35-1.85; P = 0.004] but did not improve handgrip strength [MD: 0.52 kg, 95% CI: -0.09-1.13; P = 0.09] or overall survival compared with placebo [HR: 0.99, 95% CI: 0.85-1.14; P = 0.84] in patients with advanced or metastatic cancer. Early screening to identify individuals with occult muscle loss, combined with multimodal interventions that include lifestyle therapy with resistance exercise training and dietary supplementation combined with pharmacotherapy, may be necessary to provide a sufficient stimulus to prevent or slow the cascade of tissue wasting. Rapid, cost-efficient, and feasible methods to quantify muscle and adipose tissue distribution are needed if body composition assessment is to be integrated into large-scale clinical workflows. Fully automated analysis of body composition from clinically acquired imaging is one example. The study of body composition is one of the most provocative areas in oncology that offers tremendous promise to help patients with cancer live longer and healthier lives.

Poor performance of psoas muscle index for identification of patients with higher waitlist mortality risk in cirrhosis.

Abstract: Author(s): Ebadi, Maryam; Wang, Connie W; Lai, Jennifer C; Dasarathy, Srinivasan; Kappus, Matthew R; Dunn, Michael A; Carey, Elizabeth J; Montano-Loza, Aldo J; From the Fitness, Life Enhancement, and Exercise in Liver Transplantation (FLEXIT) Consortium | Abstract: BackgroundSarcopenia, characterized by low muscle mass, associates with mortality in patients with cirrhosis. Skeletal muscle area in a single computed tomography image at the level of the third lumbar vertebrate (L3) is a valid representative of whole body muscle mass. Controversy remains regarding applicability of psoas muscle to identify patients at greater risk of mortality. We aimed to determine psoas muscle index (PMI) association with skeletal muscle index (SMI) and to evaluate the capacity of PMI to predict liver transplant waitlist mortality.MethodsWe evaluated listed adult patients with cirrhosis from 2012 to 2013 at four North American liver transplant centres. From L3 computed tomography images within 3 months of listing, we determined SMI and PMI expressed by cm2 /m2 . Low SMI was defined as SMI l39 cm2 /m2 in women and l50 cm2 /m2 in men as published by us earlier. Cut-offs for PMI to predict mortality were established using a receiver-operating characteristic analysis. Mortality predictors were determined using competing-risk analysis with reported results as subdistribution hazard ratios (sHRs).ResultsOf 353 waitlist candidates, 68% were men, mean age 56 ± 9 years, and Model for End-stage Liver Disease of 16 ± 8 points. Low SMI was present more frequently in men than women (51 vs. 36%, P = 0.02). Moderately strong correlation between SMI and PMI was observed (r g 0.7, P l 0.001). Low PMI (males l 5.1 cm2 /m2 ; females l 4.3 cm2 /m2 ) yielded poor and moderate concordance with low SMI in men and women, respectively (Kappa coefficient 0.31 and 0.63). SMI (39 ± 9 vs. 43 ± 7 cm2 /m2 ; P = 0.009) and PMI (4.4 ± 1.3 vs. 5.2 ± 1.1 cm2 /m2 ; P = 0.001) were lower in women who died and/or were delisted (compared with non-deceased patients) whereas men who died and/or were delisted had only lower SMI (47 ± 7 vs. 51 ± 9 cm2 /m2 ; P = 0.003), but not PMI compared with non-deceased patients. In women, both SMI (sHR 0.94, P = 0.048) and PMI (sHR 0.58, P = 0.002) were predictors of mortality, while in men, SMI was significant (sHR 0.95, P = 0.001) and PMI showed a trend to be (sHR 0.85, P = 0.09) associated with mortality. Overall, 104 patients (29%) were misclassified between SMI and PMI categories. Using PMI cut-offs, 66% and 28% of low SMI men and women, who have a higher risk of mortality, were incorrectly classified as low risk.ConclusionsSkeletal muscle index is a more complete and robust measurement than PMI, especially in men with cirrhosis. Low PMI identifies an incomplete subset of patients at increased risk of mortality indicated by low SMI. Given the poor performance of PMI, SMI should not be substituted by PMI.

miRNA-23a/27a attenuates muscle atrophy and renal fibrosis through muscle-kidney crosstalk.

Abstract: Background The treatment of muscle wasting is accompanied by benefits in other organs, possibly resulting from muscle-organ crosstalk. However, how the muscle communicates with these organs is less understood. Two microRNAs (miRs), miR-23a and miR-27a, are located together in a gene cluster and regulate proteins that are involved in the atrophy process. MiR-23a/27a has been shown to reduce muscle wasting and act as an anti-fibrotic agent. We hypothesized that intramuscular injection of miR-23a/27a would counteract both muscle wasting and renal fibrosis lesions in a streptozotocin-induced diabetic model. Methods We generated an adeno-associated virus (AAV) that overexpresses the miR-23a∼27a∼24-2 precursor RNA and injected it into the tibialis anterior muscle of streptozotocin-induced diabetic mice. Muscle cross-section area (immunohistology plus software measurement) and muscle function (grip strength) were used to evaluate muscle atrophy. Fibrosis-related proteins were measured by western blot to monitor renal damage. In some cases, AAV-GFP was used to mimic the miR movement in vivo, allowing us to track organ redistribution by using the Xtreme Imaging System. Results The injection of AAV-miR-23a/27a increased the levels of miR-23a and miR-27a as well as increased phosphorylated Akt, attenuated the levels of FoxO1 and PTEN proteins, and reduced the abundance of TRIM63/MuRF1 and FBXO32/atrogin-1 in skeletal muscles. It also decreased myostatin mRNA and protein levels as well as the levels of phosphorylated pSMAD2/3. Provision of miR-23a/27a attenuates the diabetes-induced reduction of muscle cross-sectional area and muscle function. Curiously, the serum BUN of diabetic animals was reduced in mice undergoing the miR-23a/27a intervention. Renal fibrosis, evaluated by Masson trichromatic staining, was also decreased as were kidney levels of phosphorylated SMAD2/3, alpha smooth muscle actin, fibronectin, and collagen. In diabetic mice injected intramuscularly with AAV-GFP, GFP fluorescence levels in the kidneys showed linear correlation with the levels in injected muscle when examined by linear regression. Following intramuscular injection of AAV-miR-23a∼27a∼24-2, the levels of miR-23a and miR-27a in serum exosomes and kidney were significantly increased compared with samples from control virus-injected mice; however, no viral DNA was detected in the kidney. Conclusions We conclude that overexpression of miR-23a/27a in muscle prevents diabetes-induced muscle cachexia and attenuates renal fibrosis lesions via muscle-kidney crosstalk. Further, this crosstalk involves movement of miR potentially through muscle originated exosomes and serum distribution without movement of AAV. These results could provide new approaches for developing therapeutic strategies for diabetic nephropathy with muscle wasting.

Serum and urine metabolomics study reveals a distinct diagnostic model for cancer cachexia

Abstract: Background Cachexia is a multifactorial metabolic syndrome with high morbidity and mortality in patients with advanced cancer. The diagnosis of cancer cachexia depends on objective measures of clinical symptoms and a history of weight loss, which lag behind disease progression and have limited utility for the early diagnosis of cancer cachexia. In this study, we performed a nuclear magnetic resonance‐based metabolomics analysis to reveal the metabolic profile of cancer cachexia and establish a diagnostic model.

Sarcopenia as a comorbidity-independent predictor of survival following radical cystectomy for bladder cancer.

Abstract: Background A multicentre study was conducted to investigate the impact of sarcopenia as an independent predictor of oncological outcome after radical cystectomy for bladder cancer. Methods In total, 500 patients with available digital computed tomography scans of the abdomen obtained within 90 days before surgery were identified. The lumbar skeletal muscle index was measured using pre-operative computed tomography. Cancer-specific survival (CSS) and overall survival (OS) were estimated using Kaplan-Meier curves. Predictors of CSS and OS were analysed by univariable and multivariable Cox regression models. Results Based on skeletal muscle index, 189 patients (37.8%) were classified as sarcopenic. Patients with sarcopenia were older compared with their counterparts (P = 0.002), but both groups were comparable regarding to gender, comorbidity, tumor, node, metastasis (TNM) stage, and type of urinary diversion (all P > 0.05). In total, 234 (46.8%) patients died, and of these, 145 (29.0%) died because of urothelial carcinoma of the bladder. Sarcopenic patients had significantly worse 5 year OS (38.3% vs. 50.5%; P = 0.002) and 5 year CSS (49.5% vs. 62.3%; P = 0.016) rates compared with patients without sarcopenia. Moreover, sarcopenia was associated independently with both increased all-cause mortality (hazard ratio, 1.43; 95% confidence interval 1.09-1.87; P = 0.01) and increased cancer-specific mortality (hazard ratio, 1.42; 95% confidence interval, 1.00-2.02; P = 0.048). Our results are limited by the lack of prospective frailty assessment. Conclusions Sarcopenia has been shown to be an independent predictor for OS and CSS in a large multicentre study with patients undergoing radical cystectomy for bladder cancer.

Impact of sarcopenia on prognostic value of cirrhosis: going beyond the hepatic venous pressure gradient and MELD score

Abstract: Background Sarcopenia has been reported as a prognostic factor. We evaluated the impact of sarcopenia to the conventional prognostic factors [Model for End‐Stage Liver Disease (MELD) score, Child–Turcotte–Pugh (CTP) score, hepatic venous pressure gradient (HVPG)] in cirrhosis.

Preoperative sarcopenia and post-operative accelerated muscle loss negatively impact survival after resection of pancreatic cancer.

Abstract: Background Sarcopenia and post-operative accelerated muscle loss leading to cachexia are commonly observed in patients with pancreatic cancer. This study aimed to assess the influence of body compositions and post-operative muscle change on survival of patients with surgically treated pancreatic cancer. Methods We analysed data of patients diagnosed with pancreatic adenocarcinoma who underwent surgery from 2008 to 2015. Skeletal muscle areas, muscle attenuation, and visceral and subcutaneous adipose tissue areas were measured from two sets of computed tomography images at L3 vertebral levels. In addition, muscle change was calculated from images obtained before and after cancer resection. We set our own cut-off values of various body compositions based on sex-specific tertiles. Results A total of 180 patients were analysed. Patients with perioperative sarcopenia (n = 60) showed poorer overall survival than those without perioperative sarcopenia (P = 0.031). Fifty (28.6%) patients with accelerated muscle loss after surgery (>10%/60 days) had poorer survival compared with the others (P = 0.029). Sarcopenia (hazard ratio, 1.79: 95% confidence interval, 1.20-2.65] and post-operative muscle change (%/60 days) (hazard ratio, 0.94: 95% confidence interval, 0.92-0.96) were identified as significant predictors of survival on multivariable analyses. Conclusions Preoperative sarcopenia identified on CT scan was associated with poor overall survival in patients with pancreatic cancer following surgery. Accelerated muscle loss after surgery also negatively impacted survival in pancreatic cancer patients.

Three cachexia phenotypes and the impact of fat-only loss on survival in FOLFIRINOX therapy for pancreatic cancer.

Abstract: Author(s): Kays, Joshua K; Shahda, Safi; Stanley, Melissa; Bell, Teresa M; O'Neill, Bert H; Kohli, Marc D; Couch, Marion E; Koniaris, Leonidas G; Zimmers, Teresa A | Abstract: BackgroundBy the traditional definition of unintended weight loss, cachexia develops in ~80% of patients with pancreatic ductal adenocarcinoma (PDAC). Here, we measure the longitudinal body composition changes in patients with advanced PDAC undergoing 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin therapy.MethodsWe performed a retrospective review of 53 patients with advanced PDAC on 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin as first line therapy at Indiana University Hospital from July 2010 to August 2015. Demographic, clinical, and survival data were collected. Body composition measurement by computed tomography (CT), trend, univariate, and multivariate analysis were performed.ResultsAmong all patients, three cachexia phenotypes were identified. The majority of patients, 64%, had Muscle and Fat Wasting (MFW), while 17% had Fat-Only Wasting (FW) and 19% had No Wasting (NW). NW had significantly improved overall median survival (OMS) of 22.6 months vs. 13.0 months for FW and 12.2 months for MFW (P = 0.02). FW (HR = 5.2; 95% confidence interval = 1.5-17.3) and MFW (HR = 1.8; 95% confidence interval = 1.1-2.9) were associated with an increased risk of mortality compared with NW. OMS and risk of mortality did not differ between FW and MFW. Progression of disease, sarcopenic obesity at diagnosis, and primary tail tumours were also associated with decreased OMS. On multivariate analysis, cachexia phenotype and chemotherapy response were independently associated with survival. Notably, CT-based body composition analysis detected tissue loss of g5% in 81% of patients, while the traditional definition of g5% body weight loss identified 56.6%.ConclusionsDistinct cachexia phenotypes were observed in this homogeneous population of patients with equivalent stage, diagnosis, and first-line treatment. This suggests cellular, molecular, or genetic heterogeneity of host or tumour. Survival among patients with FW was as poor as for MFW, indicating adipose tissue plays a crucial role in cachexia and PDAC mortality. Adipose tissue should be studied for its mechanistic contributions to cachexia.

Circulating myomiRs: a new class of biomarkers to monitor skeletal muscle in physiology and medicine.

Abstract: MicroRNAs (miRNA) are small non-coding RNAs that target mRNAs and are consequently involved in the post-transcriptional regulation of gene expression. Some miRNAs are ubiquitously expressed in tissue, while others are tissue-specific or tissue-enriched. miRNAs can be released by cells and are found in various biofluids, including serum and plasma. Thus, measuring miRNAs in the circulation may provide information on the originating tissue or cells. MyomiRs are described as striated muscle-specific or muscle-enriched miRNAs. Their circulating levels can be measured and have been proposed to be new biomarkers of physiological and pathological muscle processes. The aims of this review are to summarize the current knowledge of circulating myomiRs, to identify the types of information they can provide about skeletal muscle, and to determine how to apply that information in the fields of research and medicine.

Physical activity unveils the relationship between mitochondrial energetics, muscle quality, and physical function in older adults

Abstract: Background The concept of mitochondrial dysfunction in ageing muscle is highly controversial. In addition, emerging evidence suggests that reduced muscle oxidative capacity and efficiency underlie the aetiology of mobility loss in older adults. Here, we hypothesized that studying well-phenotyped older cohorts across a wide range of physical activity would unveil a range of mitochondrial function in skeletal muscle and in turn allow us to more clearly examine the impact of age per se on mitochondrial energetics. This also enabled us to more clearly define the relationships between mitochondrial energetics and muscle lipid content with clinically relevant assessments of muscle and physical function. Methods Thirty-nine volunteers were recruited to the following study groups: young active (YA, n = 2 women/8 men, age = 31.2 ± 5.4 years), older active (OA, n = 2 women/8 men, age = 67.5 ± 2.7 years), and older sedentary (OS, n = 8 women/11 men, age = 70.7 ± 4.7 years). Participants completed a graded exercise test to determine fitness (VO2 peak), a submaximal exercise test to determine exercise efficiency, and daily physical activity was recorded using a tri-axial armband accelerometer. Mitochondrial energetics were determined by (i) 31 P magnetic resonance spectroscopy and (ii) respirometry of fibre bundles from vastus lateralis biopsies. Quadriceps function was assessed by isokinetic dynamometry and physical function by the short physical performance battery and stair climb test. Results Daily physical activity energy expenditure was significantly lower in OS, compared with YA and OA groups. Despite fitness being higher in YA compared with OA and OS, mitochondrial respiration, maximum mitochondrial capacity, Maximal ATP production/Oxygen consumption (P/O) ratio, and exercise efficiency were similar in YA and OA groups and were significantly lower in OS. P/O ratio was correlated with exercise efficiency. Time to complete the stair climb and repeated chair stand tests were significantly greater for OS. Interestingly, maximum mitochondrial capacity was related to muscle contractile performance and physical function. Conclusions Older adults who maintain a high amount of physical activity have better mitochondrial capacity, similar to highly active younger adults, and this is related to their better muscle quality, exercise efficiency, and physical performance. This suggests that mitochondria could be an important therapeutic target for sedentary ageing associated conditions including sarcopenia, dynapenia, and loss of physical function.

The deterioration of muscle mass and radiodensity is prognostic of poor survival in stage I–III colorectal cancer: a population‐based cohort study (C‐SCANS)

Abstract: BACKGROUND Muscle abnormalities such as low muscle mass and low muscle radiodensity are well known risk factors for unfavourable cancer prognosis. However, little is known in regard to the degree and impact of longitudinal changes in muscle mass and radiodensity within the context of cancer. Here, we explore the relationship between muscle wasting and mortality in a large population-based study of patients with non-metastatic colorectal cancer (CRC). METHODS A total of 1924 patients with stage I-III CRC who underwent surgical resection in the Kaiser Permanente Northern California Health System were included. Muscle mass and radiodensity were quantified using computed tomography images obtained at diagnosis and after approximately 14 months. Cox proportional-hazards models were used to estimate hazard ratios for all-cause mortality. RESULTS The hazard ratio for all-cause mortality among patients with the largest deterioration in muscle mass (≥2 SD; ≥11.4% loss from baseline), as compared with those who remained stable (±1 SD; 0.0 ± 5.7%) was 2.15 [95% confidence interval (CI): 1.59-2.92; P < 0.001]. The hazard ratio for all-cause mortality among patients who experienced the largest deterioration in muscle radiodensity (≥2 SD; ≥20.2% loss from baseline), as compared with those who remained stable (±1 SD; 0.0 ± 10.1%) was 1.61 (95% CI: 1.20-2.15; P = 0.002). CONCLUSIONS In patients with stage I-III CRC, muscle wasting is a risk factor for mortality, independent of change in body mass and other body composition parameters.

Computed tomography diagnosed cachexia and sarcopenia in 725 oncology patients: is nutritional screening capturing hidden malnutrition?

Abstract: BACKGROUND Nutrition screening on admission to hospital is mandated in many countries, but to date, there is no consensus on which tool is optimal in the oncology setting. Wasting conditions such as cancer cachexia (CC) and sarcopenia are common in cancer patients and negatively impact on outcomes; however, they are often masked by excessive adiposity. This study aimed to inform the application of screening in cancer populations by investigating whether commonly used nutritional screening tools are adequately capturing nutritionally vulnerable patients, including those with abnormal body composition phenotypes (CC, sarcopenia, and myosteatosis). METHODS A prospective study of ambulatory oncology outpatients presenting for chemotherapy was performed. A detailed survey incorporating clinical, nutritional, biochemical, and quality of life data was administered. Participants were screened for malnutrition using the Malnutrition Universal Screening Tool (MUST), Malnutrition Screening Tool (MST), and the Nutritional Risk Index (NRI). Computed tomography (CT) assessment of body composition was performed to diagnose CC, sarcopenia, and myosteatosis according to consensus criteria. RESULTS A total of 725 patients (60% male, median age 64 years) with solid tumours participated (45% metastatic disease). The majority were overweight/obese (57%). However, 67% were losing weight, and CT analysis revealed CC in 42%, sarcopenia in 41%, and myosteatosis in 46%. Among patients with CT-identified CC, the MUST, MST, and NRI tools categorized 27%, 35%, and 7% of them as 'low nutritional risk', respectively. The percentage of patients with CT-identified sarcopenia and myosteatosis that were categorised as 'low nutritional risk' by MUST, MST and NRI were 55%, 61%, and 14% and 52%, 50%, and 11%, respectively. Among these tools, the NRI was most sensitive, with scores <97.5 detecting 85.8%, 88.6%, and 92.9% of sarcopenia, myosteatosis, and CC cases, respectively. Using multivariate Cox proportional hazards models, NRI score < 97.5 predicted greater mortality risk (hazard ratio 1.8, confidence interval: 1.2-2.8, P = 0.007). CONCLUSIONS High numbers of nutritionally vulnerable patients, with demonstrated abnormal body composition phenotypes on CT analysis, were misclassified by MUST and MST. Caution should be exercised when categorizing the nutritional risk of oncology patients using these tools. NRI detected the majority of abnormal body composition phenotypes and independently predicted survival. Of the tools examined, the NRI yielded the most valuable information from screening and demonstrated usefulness as an initial nutritional risk grading system in ambulatory oncology patients.

Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature.

Abstract: In individuals with cerebral palsy (CP), smaller muscle and atrophy are present at young age. Many people with CP also experience a decline in gross motor function as they age, which might be explained by the loss of muscle mass. The clinical observation of muscle wasting has prompted a comparison with sarcopenia in older adults, and the term accelerated musculoskeletal ageing is often used to describe the hallmark phenotype of CP through the lifespan. However, there has been very little research emphasis on the natural history of ageing with CP and even less with respect to the determinants or prevention of muscle loss with CP. Considering the burgeoning interest in the science of muscle preservation, this paper aims to (i) describe the characteristics of accelerated musculoskeletal ageing in people with CP, (ii) describe the pathophysiology of sarcopenia and parallels with CP, and (iii) discuss possible therapeutic approaches, based on established approaches for sarcopenia.

LY2495655, an antimyostatin antibody, in pancreatic cancer: a randomized, phase 2 trial.

Abstract: BACKGROUND Cachexia is a formidable clinical challenge in pancreatic cancer. We assessed LY2495655 (antimyostatin antibody) plus standard-of-care chemotherapy in pancreatic cancer using cachexia status as a stratifier. METHODS In this randomized, phase 2 trial, patients with stage II-IV pancreatic cancer were randomized to 300 mg LY2495655, 100 mg LY2495655, or placebo, plus physician-choice chemotherapy from a prespecified list of standard-of-care regimens for first and later lines of care. Investigational treatment was continued during second-line treatment. The primary endpoint was overall survival. RESULTS Overall, 125 patients were randomized. In August 2014, 300 mg LY2495655 was terminated due to imbalance in death rates between the treatment arms; in January 2015, 100 mg LY2495655 treatment was terminated due to futility. LY2495655 did not improve overall survival: the hazard ratio was 1.70 (90% confidence interval, 1.1-2.7) for 300 mg vs. placebo and 1.3 (0.82-2.1) for 100 mg vs. placebo (recommended doses). Progression-free survival results were consistent with the overall survival results. A numerically higher hazard ratio was observed in patients with weight loss (WL) of ≥5% (cachexia) than with <5% WL within 6 months before randomization. Subgroup analyses for patients stratified by WL in the 6 months preceding enrollment suggested that functional responses to LY2495655 (either dose) may have been superior in patients with <5% WL vs. patients with ≥5% WL. Among possibly drug-related adverse events, fatigue, diarrhoea, and anorexia were more common in LY2495655-treated than in placebo-treated patients. CONCLUSIONS In the intention-to-treat analysis, LY2495655 did not confer clinical benefit in pancreatic cancer. Our data highlight the importance of assessing survival when investigating therapeutic management of cachexia and support the use of WL as a stratifier (independent of performance status).

Protein imbalance in the development of skeletal muscle wasting in tumour‐bearing mice

Abstract: Background Cancer cachexia occurs in approximately 80% of cancer patients and is a key contributor to cancer-related death. The mechanisms controlling development of tumour-induced muscle wasting are not fully elucidated. Specifically, the progression and development of cancer cachexia are underexplored. Therefore, we examined skeletal muscle protein turnover throughout the development of cancer cachexia in tumour-bearing mice. Methods Lewis lung carcinoma (LLC) was injected into the hind flank of C57BL6/J mice at 8 weeks age with tumour allowed to develop for 1, 2, 3, or 4 weeks and compared with PBS injected control. Muscle size was measured by cross-sectional area analysis of haematoxylin and eosin stained tibialis anterior muscle. 2 H2 O was used to assess protein synthesis throughout the development of cancer cachexia. Immunoblot and RT-qPCR were used to measure regulators of protein turnover. TUNEL staining was utilized to measure apoptotic nuclei. LLC conditioned media (LCM) treatment of C2C12 myotubes was used to analyse cancer cachexia in vitro. Results Muscle cross-sectional area decreased ~40% 4 weeks following tumour implantation. Myogenic signalling was suppressed in tumour-bearing mice as soon as 1 week following tumour implantation, including lower mRNA contents of Pax7, MyoD, CyclinD1, and Myogenin, when compared with control animals. AchRδ and AchRe mRNA contents were down-regulated by ~50% 3 weeks following tumour implantation. Mixed fractional synthesis rate protein synthesis was ~40% lower in 4 week tumour-bearing mice when compared with PBS controls. Protein ubiquitination was elevated by ~50% 4 weeks after tumour implantation. Moreover, there was an increase in autophagy machinery after 4 weeks of tumour growth. Finally, ERK and p38 MAPK phosphorylations were fourfold and threefold greater than control muscle 4 weeks following tumour implantation, respectively. Inhibition of p38 MAPK, but not ERK MAPK, in vitro partially rescued LCM-induced loss of myotube diameter. Conclusions Our findings work towards understanding the pathophysiological signalling in skeletal muscle in the initial development of cancer cachexia. Shortly following the onset of the tumour-bearing state alterations in myogenic regulatory factors are apparent, suggesting early onset alterations in the capacity for myogenic induction. Cancer cachexia presents with a combination of a loss of protein synthesis and increased markers of protein breakdown, specifically in the ubiquitin-proteasome system. Also, p38 MAPK may be a potential therapeutic target to combat cancer cachexia via a p38-FOX01-atrogene-ubiquitin-proteasome mechanism.

Prevalence of rheumatoid cachexia in rheumatoid arthritis: a systematic review and meta-analysis.

Abstract: Background Low muscle mass occurs in patients with rheumatoid arthritis without weight loss; this condition is referred as rheumatoid cachexia. The aim of the current study was to perform a systematic review with meta-analysis to determine the rheumatoid cachexia prevalence. Methods A systematic review with meta-analysis of observational studies published in English, between 1994 and 2016, was conducted using MEDLINE (via PubMed) and other relevant sources. Search strategies were based on pre-defined keywords and medical subject headings. The methodological quality of included studies was assessed using the Newcastle-Ottawa Scale. Meta-analysis was used to estimate the prevalence, and because studies reported different methods and criteria to estimate body composition and prevalence of rheumatoid cachexia, subgroup analyses were performed. Meta-regression adjusted for the 28-joint disease activity score and disease duration (years) was performed (significance level at P ≤ 0.05). Results Of 136 full articles (one duplicate publication) screened for inclusion in the study, eight were included. The estimated overall prevalence of rheumatoid cachexia was 19% [95% confidence interval (CI) 07-33%]. This prevalence was 29% (95% CI 15-46%) when body composition was measured by dual-energy X-ray absorptiometry. When the diagnostic criteria were fat-free mass index below the 10th percentile and fat mass index above the 25th percentile, rheumatoid cachexia prevalence was 32% (95% CI 14-52%). The 28-joint disease activity score and disease duration had no influence on the estimated prevalence of rheumatoid cachexia (P > 0.05). Most studies were rated as having moderate methodological quality. Conclusions Meta-analysis showed a prevalence of rheumatoid cachexia of 15-32%, according to different criteria, demonstrating that this condition is a frequent comorbidity of rheumatoid arthritis. To better understand its clinical impact, more studies using standardized definitions and prospective evaluations are urgently needed.

Growth of ovarian cancer xenografts causes loss of muscle and bone mass: a new model for the study of cancer cachexia.

Abstract: BACKGROUND Cachexia frequently occurs in women with advanced ovarian cancer (OC), along with enhanced inflammation. Despite being responsible for one third of all cancer deaths, cachexia is generally under-studied in OC due to a limited number of pre-clinical animal models. We aimed to address this gap by characterizing the cachectic phenotype in a mouse model of OC. METHODS Nod SCID gamma mice (n = 6-10) were injected intraperitoneally with 1 × 107 ES-2 human OC cells to mimic disseminated abdominal disease. Muscle size and strength, as well as bone morphometry, were assessed. Tumour-derived effects on muscle fibres were investigated in C2C12 myotube cultures. IL-6 levels were detected in serum and ascites from tumour hosts, as well as in tumour sections. RESULTS In about 2 weeks, ES-2 cells developed abdominal tumours infiltrating omentum, mesentery, and adjacent organs. The ES-2 tumours caused severe cachexia with marked loss of body weight (-12%, P < 0.01) and ascites accumulation in the peritoneal cavity (4.7 ± 1.5 mL). Skeletal muscles appeared markedly smaller in the tumour-bearing mice (approximately -35%, P < 0.001). Muscle loss was accompanied by fibre atrophy, consistent with reduced muscle cross-sectional area (-34%, P < 0.01) and muscle weakness (-50%, P < 0.001). Body composition assessment by dual-energy X-ray absorptiometry revealed decreased bone mineral density (-8%, P < 0.01) and bone mineral content (-19%, P < 0.01), also consistent with reduced trabecular bone in both femurs and vertebrae, as suggested by micro-CT imaging of bone morphometry. In the ES-2 mouse model, cachexia was also associated with high tumour-derived IL-6 levels in plasma and ascites (26.3 and 279.6 pg/mL, respectively) and with elevated phospho-STAT3 (+274%, P < 0.001), reduced phospho-AKT (-44%, P < 0.001) and decreased mitochondrial proteins, as well as with increased protein ubiquitination (+42%, P < 0.001) and expression of ubiquitin ligases in the skeletal muscle of tumour hosts. Similarly, ES-2 conditioned medium directly induced fibre atrophy in C2C12 mouse myotubes (-16%, P < 0.001), consistent with elevated phospho-STAT3 (+1.4-fold, P < 0.001) and altered mitochondrial homoeostasis and metabolism, while inhibition of the IL-6/STAT3 signalling by means of INCB018424 was sufficient to restore the myotubes size. CONCLUSIONS Our results suggest that the development of ES-2 OC promotes muscle atrophy in both in vivo and in vitro conditions, accompanied by loss of bone mass, enhanced muscle protein catabolism, abnormal mitochondrial homoeostasis, and elevated IL-6 levels. Therefore, this represents an appropriate model for the study of OC cachexia. Our model will aid in identifying molecular mediators that could be effectively targeted in order to improve muscle wasting associated with OC.

Iron deficiency as energetic insult to skeletal muscle in chronic diseases.

Abstract: Specific skeletal myopathy constitutes a common feature of heart failure, chronic obstructive pulmonary disease, and type 2 diabetes mellitus, where it can be characterized by the loss of skeletal muscle oxidative capacity. There is evidence from in vitro and animal studies that iron deficiency affects skeletal muscle functioning mainly in the context of its energetics by limiting oxidative metabolism in favour of glycolysis and by alterations in both carbohydrate and fat catabolic processing. In this review, we depict the possible molecular pathomechanisms of skeletal muscle energetic impairment and postulate iron deficiency as an important factor causally linked to loss of muscle oxidative capacity that contributes to skeletal myopathy seen in patients with heart failure, chronic obstructive pulmonary disease, and type 2 diabetes mellitus.

RAGE in the pathophysiology of skeletal muscle.

Abstract: Emerging evidence suggests that the signalling of the Receptor for Advanced Glycation End products (RAGE) is critical for skeletal muscle physiology controlling both the activity of muscle precursors during skeletal muscle development and the correct time of muscle regeneration after acute injury. On the other hand, the aberrant re-expression/activity of RAGE in adult skeletal muscle is a hallmark of muscle wasting that occurs in response to ageing, genetic disorders, inflammatory conditions, cancer, and metabolic alterations. In this review, we discuss the mechanisms of action and the ligands of RAGE involved in myoblast differentiation, muscle regeneration, and muscle pathological conditions. We highlight potential therapeutic strategies for targeting RAGE to improve skeletal muscle function.

Introducing the 'Drucebo' effect in statin therapy: a systematic review of studies comparing reported rates of statin-associated muscle symptoms, under blinded and open-label conditions

Abstract: Background: The ‘placebo effect’ and ‘nocebo effect’ are phenomena whereby beneficial (placebo) or adverse (nocebo) effects result from the expectation that an inert substance will relieve or cause a particular symptom. These terms are often inappropriately applied to effects experienced on drug therapy. Quantifying the magnitude of placebo and nocebo effects in clinical trials is problematic because it requires a ‘no treatment’ arm. To overcome the difficulties associated with measuring the nocebo effect, and the fact that its definition refers to inert compounds, rather than drugs, we introduce the concept of ‘drucebo’ (a combination of DRUg and plaCEBO or noCEBO) to relate to beneficial or adverse effects of a drug, which result from expectation and are not pharmacologically caused by the drug. As an initial application of the concept, we have estimated the contribution of the drucebo effect to statin discontinuation and statin‐induced muscle symptoms by performing a systematic review of randomized controlled trial of statin therapy. Methods: This preferred reporting items for systematic reviews and meta‐analysis‐compliant systematic review was prospectively registered in PROSPERO (CRD42017082700). We searched PubMed and Cochrane Central from inception until 3 January 2018 using a search strategy designed to detect studies including the concepts (Statins AND Placebo AND muscle pain). We included studies that allowed us to quantify the drucebo effect for adverse muscle symptoms of statins by (i) comparing reported rates of muscle symptoms in blinded and unblinded phases of randomized controlled trials and (ii) comparing rates of muscle symptoms at baseline and during blinded therapy in trials that included patients with objectively confirmed statin intolerance at baseline. Extraction was performed by two researchers with disagreements settled by a third reviewer. Results: Five studies allowed the estimation of the drucebo effect. All trials demonstrated an excess of side effects under open‐label conditions. The contribution of the drucebo effect to statin‐associated muscle pain ranged between 38% and 78%. The heterogeneity of study methods, outcomes, and reporting did not allow for quantitative synthesis (meta‐analysis) of the results. Conclusions: The drucebo effect may be useful in evaluating the safety and efficacy of medicines. Diagnosis of the drucebo effect in patients presenting with statin intolerance will allow restoration of life‐prolonging lipid‐lowering therapy. Our study was limited by heterogeneity of included studies and lack of access to individual patient data. Further studies are necessary to better understand risk factors for and clinical management of the drucebo effect.

Short‐term disuse promotes fatty acid infiltration into skeletal muscle

Abstract: Background Many physiological and/or pathological conditions lead to muscle deconditioning, a well-described phenomenon characterized by a loss of strength and muscle power mainly due to the loss of muscle mass. Fatty infiltrations, or intermuscular adipose tissue (IMAT), are currently well-recognized components of muscle deconditioning. Despite the fact that IMAT is present in healthy human skeletal muscle, its increase and accumulation are linked to muscle dysfunction. Although IMAT development has been largely attributable to inactivity, the precise mechanisms of its establishment are still poorly understood. Because the sedentary lifestyle that accompanies age-related sarcopenia may favour IMAT development, deciphering the early processes of muscle disuse is of great importance before implementing strategies to limit IMAT deposition. Methods In our study, we took advantage of the dry immersion (DI) model of severe muscle inactivity to induce rapid muscle deconditioning during a short period. During the DI, healthy adult men (n = 12; age: 32 ± 5) remained strictly immersed, in a supine position, in a controlled thermo-neutral water bath. Skeletal muscle biopsies were obtained from the vastus lateralis before and after 3 days of DI. Results We showed that DI for only 3 days was able to decrease myofiber cross-sectional areas (-10.6%). Moreover, protein expression levels of two key markers commonly used to assess IMAT, perilipin, and fatty acid binding protein 4, were upregulated. We also observed an increase in the C/EBPα and PPARγ protein expression levels, indicating an increase in late adipogenic processes leading to IMAT development. While many stem cells in the muscle environment can adopt the capacity to differentiate into adipocytes, fibro-adipogenic progenitors (FAPs) represent the population that appears to play a major role in IMAT development. In our study, we showed an increase in the protein expression of PDGFRα, the specific cell surface marker of FAPs, in response to 3 days of DI. It is well recognized that an unfavourable muscle environment drives FAPs to ectopic adiposity and/or fibrosis. Conclusions This study is the first to emphasize that during a short period of severe inactivity, muscle deconditioning is associated with IMAT development. Our study also reveals that FAPs could be the main resident muscle stem cell population implicated in ectopic adiposity development in human skeletal muscle.

Aspiration pneumonia induces muscle atrophy in the respiratory, skeletal, and swallowing systems.

Abstract: Background Repetition of the onset of aspiration pneumonia in aged patients is common and causes chronic inflammation. The inflammation induces proinflammatory cytokine production and atrophy in the muscles. The proinflammatory cytokines induce muscle proteolysis by activating calpains and caspase-3, followed by further degradation by the ubiquitin-proteasome system. Autophagy is another pathway of muscle atrophy. However, little is known about the relationship between aspiration pneumonia and muscle. For swallowing muscles, it is not clear whether they produce cytokines. The main objective of this study was to determine whether aspiration pneumonia induces muscle atrophy in the respiratory (the diaphragm), skeletal (the tibialis anterior, TA), and swallowing (the tongue) systems, and their possible mechanisms. Methods We employed a mouse aspiration pneumonia model and computed tomography (CT) scans of aged pneumonia patients. To induce aspiration pneumonia, mice were inoculated with low dose pepsin and lipopolysaccharide solution intra-nasally 5 days a week. The diaphragm, TA, and tongue were isolated, and total RNA, proteins, and frozen sections were stored. Quantitative real-time polymerase chain reaction determined the expression levels of proinflammatory cytokines, muscle E3 ubiquitin ligases, and autophagy related genes. Western blot analysis determined the activation of the muscle proteolysis pathway. Frozen sections determined the presence of muscle atrophy. CT scans were used to evaluate the muscle atrophy in aged aspiration pneumonia patients. Results The aspiration challenge enhanced the expression levels of proinflammatory cytokines in the diaphragm, TA, and tongue. Among muscle proteolysis pathways, the aspiration challenge activated caspase-3 in all the three muscles examined, whereas calpains were activated in the diaphragm and the TA but not in the tongue. Activation of the ubiquitin-proteasome system was detected in all the three muscles examined. The aspiration challenge activated autophagy in the TA and the tongue, whereas weak or little activation was detected in the diaphragm. The aspiration challenge resulted in a greater proportion of smaller myofibers than in controls in the diaphragm, TA, and tongue, suggesting muscle atrophy. CT scans clearly showed that aspiration pneumonia was followed by muscle atrophy in aged patients. Conclusions Aspiration pneumonia induced muscle atrophy in the respiratory, skeletal, and swallowing systems in a preclinical animal model and in human patients. Diaphragmatic atrophy may weaken the force of cough to expectorate sputum or mis-swallowed contents. Skeletal muscle atrophy may cause secondary sarcopenia. The atrophy of swallowing muscles may weaken the swallowing function. Thus, muscle atrophy could become a new therapeutic target of aspiration pneumonia.

Healthy community-living older men differ from women in associations between myostatin levels and skeletal muscle mass.

Abstract: BACKGROUND Myostatin is a negative regulator of muscle growth but the relationship between serum myostatin levels and muscle mass is unclear. This study investigated the association between serum myostatin levels and skeletal muscle mass among healthy older community residents in Taiwan, to evaluate the potential of serum myostatin as a biomarker for diagnosing sarcopenia and/or evaluating the effect of its treatment. METHODS Study data were excerpted from a random subsample of the I-Lan Longitudinal Aging Study population. Serum myostatin levels were determined and categorized into tertiles (low, medium, high). Relative appendicular skeletal muscle mass (RASM) was calculated as appendicular lean body mass by dual-energy X-ray absorptiometry divided by height squared (kg/m2 ). Low muscle mass was defined as recommended by the Asian Working Group for Sarcopenia. RESULTS The analytic study sample comprised 463 adults (mean age: 69.1 years; 49.5% men). Compared with subjects with normal RASM, those with lower RASM were older and frailer, with significantly higher prevalence of malnutrition, lower serum dehydroepiandrosterone (DHEA) levels, and were more likely to have low serum myostatin status. Multivariable logistic regression analysis showed that male sex (OR 3.60, 95% CI 1.30-9.92), malnutrition (OR 4.39, 95% CI 1.56-12.36), DHEA (OR 0.99, 95% CI 0.99-1.00), and low myostatin (OR 3.23, 95% CI 1.49-7.01) were all independent risk factors for low RASM (all P < 0.05). In men, DHEA (OR 0.99, 95% CI 0.98-1.00) and low myostatin (OR 4.89, 95% CI 1.79-13.37) were significantly associated with low RASM (both P < 0.05); however, only malnutrition was associated with low RASM in women (OR 13.59, 95% CI 2.22-83.25, P < 0.05). CONCLUSIONS Among healthy community-living older adults, low serum myostatin levels were associated with low skeletal muscle mass in men, but not in women. Our results do not support using serum myostatin levels to diagnose sarcopenia, or to monitor how it responds to treatments. Further research is needed to understand why men apparently differ from women in the interrelationship between their myostatin levels and muscle mass.