Sex Differences in Muscle Wasting

Interactions of Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldichloroethylene (DDE) With Skeletal Muscle Ryanodine Receptor Type 1

Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and detected in tissues of living organisms. Although DDT owes its insecticidal activity to impeding closure of voltage-gated sodium channels, it mediates toxicity in mammals by acting as an endocrine disruptor (ED). Numerous studies demonstrate DDT/DDE to be EDs, but studies examining muscle-specific effects mediated by nonhormonal receptors in mammals are lacking. Therefore, we investigated whether o,p'-DDT, p,p'-DDT, o,p'-DDE, and p,p'-DDE (DDx, collectively) alter the function of ryanodine receptor type 1 (RyR1), a protein critical for skeletal muscle excitation-contraction coupling and muscle health. DDx (0.01-10 µM) elicited concentration-dependent increases in [3H]ryanodine ([3H]Ry) binding to RyR1 with o,p'-DDE showing highest potency and efficacy. DDx also showed sex differences in [3H]Ry-binding efficacy toward RyR1, where [3H]Ry-binding in female muscle preparations was greater than male counterparts. Measurements of Ca2+ transport across sarcoplasmic reticulum (SR) membrane vesicles further confirmed DDx can selectively engage with RyR1 to cause Ca2+ efflux from SR stores. DDx also disrupts RyR1-signaling in HEK293T cells stably expressing RyR1 (HEK-RyR1). Pretreatment with DDx (0.1-10 µM) for 100 s, 12 h, or 24 h significantly sensitized Ca2+-efflux triggered by RyR agonist caffeine in a concentration-dependent manner. o,p'-DDE (24 h; 1 µM) significantly increased Ca2+-transient amplitude from electrically stimulated mouse myotubes compared with control and displayed abnormal fatigability. In conclusion, our study demonstrates DDx can directly interact and modulate RyR1 conformation, thereby altering SR Ca2+-dynamics and sensitize RyR1-expressing cells to RyR1 activators, which may ultimately contribute to long-term impairments in muscle health.

Risk Factors for Muscle Loss in Hemodialysis Patients with High Comorbidity

With expanding kidney transplantation programs, remaining hemodialysis patients are more likely to have a high comorbidity burden and may therefore be more prone to lose muscle mass. Our aim was to analyze risk factors for muscle loss in hemodialysis patients with high comorbidity. Fifty-four chronic hemodialysis patients (Charlson Comorbidity Index 9.0 ± 3.4) were followed for 20 weeks using 4-weekly measurements of lean tissue mass, intracellular water, and body cell mass (proxies for muscle mass), handgrip strength (HGS), and biochemical parameters. Mixed models were used to analyze covariate effects on LTM. LTM (-6.4 kg, interquartile range [IQR] -8.1 to -4.8), HGS (-1.9 kg, IQR -3.1 to -0.7), intracellular water (-2.11 L, IQR -2.9 to -1.4) and body cell mass (-4.30 kg, IQR -5.9 to -2.9) decreased in all patients. Conversely, adipose tissue mass increased (4.5 kg, IQR 2.7 to 6.2), resulting in no significant change in body weight (-0.5 kg, IQR -1.0 to 0.1). Independent risk factors for LTM loss over time were male sex (-0.26 kg/week, 95% CI -0.33 to -0.19), C-reactive protein above median (-0.1 kg/week, 95% CI -0.2 to -0.001), and baseline lean tissue index ³10th percentile (-1.6 kg/week, 95% CI -2.1 to -1.0). Age, dialysis vintage, serum albumin, comorbidity index, and diabetes did not significantly affect LTM loss over time. In this cohort with high comorbidity, we found universal and prominent muscle loss, which was further accelerated by male sex and inflammation. Stable body weight may mask muscle loss because of concurrent fat gain. Our data emphasize the need to assess body composition in all hemodialysis patients and call for studies to analyze whether intervention with nutrition or exercise may curtail muscle loss in the most vulnerable hemodialysis patients.

Low relative skeletal muscle mass predicts incident hypertension in Korean men: a prospective cohort study

OBJECTIVE

Previous cross-sectional studies suggest an association between low muscle mass and hypertension. However, whether low muscle mass predicts the development of hypertension is unknown. The aim of this study is to investigate the relationship between relative muscle mass and incident hypertension in a large prospective cohort of Korean adults.

METHODS

In this prospective cohort study, we analyzed 132 324 participants without hypertension at baseline who underwent two health check-ups in 2012 and 2016 or in 2013 and 2017 with a 4-year interval. The participants were divided according to skeletal muscle mass index quartiles (Q1--Q4) according to their baseline skeletal muscle mass index [skeletal muscle mass index (%) = total skeletal muscle mass (kg)/body weight (kg) × 100). Multivariate logistic regression was used to estimate the odds ratio and 95% confidence interval for the development of hypertension after 4 years.

RESULTS

After 4 years, 7180 (5.43%) participants developed hypertension. The incidence rates of hypertension were 12.11, 8.58, 6.93, and 4.37% in men and 4.02, 2.29, 1.73, and 1.18% in women in Q1, Q2, Q3, and Q4, respectively. The multivariate adjusted odds ratios (95% confidence intervals) for incident hypertension in Q1, Q2, and Q3, in comparison with Q4, were 1.46 (1.3-1.63), 1.31 (1.19-1.46), and 1.26 (1.14-1.40) in men and 0.97 (0.76-1.23), 1.12 (0.90-1.38), and 1.14 (0.92-1.42) in women, respectively.

CONCLUSION

Low relative skeletal muscle mass was independently and significantly associated with the incidence of hypertension only in Korean men. Further research is required to understand the underlying mechanisms of this relationship.

Sex-and race-specific associations of protein intake with change in muscle mass and physical function in older adults: the Health, Aging, and Body Composition (Health ABC) Study

BACKGROUND

Protein intake recommendations advise ≥0.8 g/kg body weight (BW)/d, whereas experts propose a higher intake for older adults (1.0-1.2 g/kg BW/d). It is unknown whether optimal protein intake differs by sex or race.

OBJECTIVES

We examined the shape of sex- and race-specific associations of dietary protein intake with 3- and 6-y changes in appendicular lean mass (aLM) and gait speed and also 6-y incidence of mobility limitation in community-dwelling older men and women.

METHODS

We used data on men (n = 1163) and women (n = 1237) aged 70-81 y of the Health, Aging, and Body Composition Study. Protein intake was assessed using an FFQ (1998-1999). aLM and gait speed were measured at baseline and at 3 and 6 y. Difficulty walking one-quarter mile or climbing stairs was measured every 6 mo over 6 y. Prospective associations were evaluated with linear and Cox regression models, comparing fit of models with and without spline functions. All analyses were stratified by sex and additionally by race.

RESULTS

Mean ± SD protein intake was 0.94 ± 0.36 g/kg adjusted body weight (aBW)/d in men and 0.95 ± 0.36 g/kg aBW/d in women. There were no strong indications of nonlinear associations. In women, higher protein intake was associated with less aLM loss over 3 y (adjusted B per 0.1 g/kg aBW/d: 39.4; 95% CI: 11.6, 67.2), specifically in black women, but not over 6 y or with gait speed decline. In men, protein intake was not associated with changes in aLM and gait speed. Higher protein intake was associated with a lower risk of mobility limitation in men (adjusted HR per 1.0 g/kg aBW/d: 0.55; 95% CI: 0.34, 0.91) and women (adjusted HR: 0.56; 95% CI: 0.33, 0.94), specifically white women.

CONCLUSIONS

Associations between protein intake and physical outcomes may vary by sex and race. Therefore, it is important to consider sex and race in future studies regarding protein needs in older adults.

Sex- and age-specific effects of energy intake and physical activity on sarcopenia

Sarcopenia is a common health issue that is not limited to only elderly patients. However, many studies have reported factors to prevent sarcopenia only in susceptible groups. This study evaluates the relationship of the total energy intake to basal metabolic rate ratio (EI/BMR) and physical activity (PA) with sarcopenia. A second aim was to analyze the interaction between EI/BMR and PA by sex and age. We analyzed 16,313 subjects aged ≥ 19 years who had dual‒energy X-ray absorptiometry data. Sarcopenia was defined as appendicular lean mass/weight (%) that was 1 standard deviation below the sex-specific mean value for a young reference group. Multivariate logistic regression analysis was used to examine the interaction between EI/BMR and PA. In this study, as EI/BMR increased, the risk of sarcopenia decreased, particularly in the older groups. Both high PA and high EI/BMR were independently related to the reduced risk of sarcopenia and showed additive effects on reducing the risk in young male and older groups. However, high PA was associated with an increased risk of sarcopenia in the young female group with low energy intake. Our findings suggest that an adequate balance between energy intake and PA is related to a low risk of sarcopenia, especially in young females.

Sex differences in disease activity and efficacy of treatment in spondyloarthritis: is body composition the cause?

PURPOSE OF REVIEW

The body composition and fat distribution is different between men and women, with different levels of circulating adipokines. These differences become more evident when suffering from an inflammatory disease, such as spondyloarthritris. In this review, we will explore the influence of obesity, body composition and adipokines on the differences in disease activity, progression and response to treatment, between men and women with spondyloarthritis.

RECENT FINDINGS

Obesity, mainly determined by the body fat content, which is higher in women, is related to worse disease activity scores. Men with higher disease activity lose more muscle mass than women. Leptin, which is usually found at higher levels in overweight women, seems to be associated with greater spinal radiographic progression when it rises during the course of the disease. Being a woman and obesity, mainly because of the body fat content, are related to a worse response to TNF-α blockers.

SUMMARY

Overlooking biological sex variation in body composition, circulating adipokines and hormonal levels, and the subsequent differences in clinical presentation, may ultimately hamper clinical treatment.

Phenotypic Variability Among Patients With D4Z4 Reduced Allele Facioscapulohumeral Muscular Dystrophy

IMPORTANCE

Facioscapulohumeral muscular dystrophy (FSHD) is considered an autosomal dominant disorder, associated with the deletion of tandemly arrayed D4Z4 repetitive elements. The extensive use of molecular analysis of the D4Z4 locus for FSHD diagnosis has revealed wide clinical variability, suggesting that subgroups of patients exist among carriers of the D4Z4 reduced allele (DRA).

OBJECTIVE

To investigate the clinical expression of FSHD in the genetic subgroup of carriers of a DRA with 7 to 8 repeat units (RUs).

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cross-sectional study included 422 carriers of DRA with 7 to 8 RUs (187 unrelated probands and 235 relatives) from a consecutive sample of 280 probands and 306 relatives from the Italian National Registry for FSHD collected between 2008 and 2016. Participants were evaluated by the Italian Clinical Network for FSHD, and all clinical and molecular data were collected in the Italian National Registry for FSHD database. Data analysis was conducted from January 2017 to June 2018.

MAIN OUTCOMES AND MEASURES

The phenotypic classification of probands and relatives was obtained by applying the Comprehensive Clinical Evaluation Form which classifies patients in the 4 following categories: (1) participants presenting facial and scapular girdle muscle weakness typical of FSHD (category A, subcategories A1-A3), (2) participants with muscle weakness limited to scapular girdle or facial muscles (category B, subcategories B1 and B2), (3) asymptomatic or healthy participants (category C, subcategories C1 and C2), and (4) participants with myopathic phenotypes presenting clinical features not consistent with FSHD canonical phenotype (category D, subcategories D1 and D2).

RESULTS

A total of 187 probands (mean [SD] age at last neurological examination, 53.5 [15.2] years; 103 [55.1%] men) and 235 relatives (mean [SD] age at last neurologic examination, 45.1 [17.0] years; 104 [44.7%] men) with a DRA with 7 to 8 RUs and a molecular diagnosis of FSHD were evaluated. Of 187 probands, 99 (52.9%; 95% CI, 45.7%-60.1%) displayed the classic FSHD phenotype, whereas 86 (47.1%; 95% CI, 39.8%-54.3%) presented incomplete or atypical phenotypes. Of 235 carrier relatives from 106 unrelated families, 124 (52.8%; 95% CI, 46.4%-59.7%) had no motor impairment, whereas a small number (38 [16.2%; 95% CI, 9.8%-23.1%]) displayed the classic FSHD phenotype, and 73 (31.0%; 95% CI, 24.7%-38.0%) presented with incomplete or atypical phenotypes. In 37 of 106 families (34.9%; 95% CI, 25.9%-44.8%), the proband was the only participant presenting with a myopathic phenotype, while only 20 families (18.9%; 95% CI, 11.9%-27.6%) had a member with autosomal dominant FSHD.

CONCLUSIONS AND RELEVANCE

This study found large phenotypic variability associated with individuals carrying a DRA with 7 to 8 RUs, in contrast to the indication that a positive molecular test is the only determining aspect for FSHD diagnosis. These findings suggest that carriers of a DRA with 7 to 8 RUs constitute a genetic subgroup different from classic FSHD. Based on these results, it is recommended that clinicians use the Comprehensive Clinical Evaluation Form for clinical classification and, whenever possible, study the extended family to provide the most adequate clinical management and genetic counseling.

Diet quality in late midlife is associated with faster walking speed in later life in women, but not men: findings from a prospective British birth cohort

Healthy diet has been linked to better age-related functioning, but evidence on the relationship of diet quality in late midlife and measures of physical capability in later life is limited. Research on potential sex differences in this relationship is scarce. The aim was to investigate the prospective association between overall diet quality, as assessed by the Healthy Eating Index-2015 (HEI-2015) at 60-64 years and measures of walking speed 7 years later, among men and women from the Insight 46, a neuroscience sub-study of the Medical Research Council National Survey of Health and Development. Diet was assessed at 60-64 years using 5-d food diaries, from which total HEI-2015 was calculated. At 69-71 years, walking speed was estimated during four 10-m walks at self-selected pace, using inertial measurement units. Multivariable linear regression models with sex as a modifier, controlling for age, follow-up, lifestyle, health/social variables and physical performance, were used. The final sample consists of 164 women and 167 men (n 331). Women had higher HEI-2015 and slower walking speed than men. A 10-point increase in HEI-2015 was associated with faster walking speed among women (B 0·024, 95 % CI 0·006, 0·043), but not men. The association remained significant in the multivariable model (B 0·021, 95 % CI 0·003, 0·040). In women, higher diet quality in late midlife is associated with faster walking speed. A healthy diet in late midlife is likely to contribute towards better age-related physical capability, and sex differences are likely to affect this relationship.

A preliminary study to identify the likely risk for sarcopenia in older hospitalised patients with cardiovascular disease in Vietnam

OBJECTIVE

To investigate the prevalence of sarcopenia, its associated factors and its impact on readmission in older hospitalised patients with cardiovascular diseases (CVD) in Vietnam.

METHODS

Patients aged ≥60 with CVD were recruited from 12/2018 to 6/2019 at a tertiary hospital in Vietnam. Sarcopenia was defined by the criteria proposed by the Asian Working Group for Sarcopenia (AWGS).

RESULTS

There were 251 participants, with a mean age of 73.7 ± 8.8, 39.4% were female, and 34.3% had sarcopenia. On multivariable logistic regression, heart failure, chronic kidney disease and being currently unmarried were significantly associated with sarcopenia. The incidence of 5-month readmission was 35.7% (50.0% in sarcopenic participants and 27.9% in non-sarcopenic participants, P = .001). Sarcopenia independently increased the risk of readmission (adjusted OR 2.19, 95% CI 1.08-4.42).

CONCLUSION

Sarcopenia was present in one-third of older hospitalised patients with CVD and increased their risk of readmission. This finding suggests the need to raise awareness of sarcopenia among clinicians and older patients in Vietnam.

Fruit and Vegetable Consumption and Sarcopenia among Older Adults in Low- and Middle-Income Countries

Fruit and vegetable consumption may protect against sarcopenia but there are no studies on this topic from low- and middle-income countries (LMICs). Thus, we assessed this association among older adults from six LMICs. Community-based cross-sectional data of the Study on Global Aging and Adult Health were analyzed. Sarcopenia was defined as the presence of low skeletal muscle mass based on indirect population formula, and either slow gait or low handgrip strength. Quintiles of vegetable and fruit consumption were created based on the number of servings consumed on a typical day. Multivariable logistic regression analysis was conducted. The sample consisted of 14,585 individuals aged ≥65 years (mean (SD) age 72.6 (11.4) years; 55% females). Adjusted analyses showed that overall, compared to the lowest quintile (Q1), the highest quintile (Q5) of fruit consumption was associated with a 40% lower odds for sarcopenia (OR = 0.60; 95% CI = 0.42−0.84) but this association was largely driven by the strong association among females (e.g., Q5 vs. Q1 OR = 0.42; 95% CI = 0.24−0.73), with no significant associations found among males. Vegetable consumption was not significantly associated with sarcopenia. Future studies of longitudinal design may shed light on whether increasing fruit consumption among older females in LMICs may reduce risk for sarcopenia.

Weighing the role of skeletal muscle mass and muscle density in cancer patients receiving PD-1/PD-L1 checkpoint inhibitors: a multicenter real-life study

Sarcopenia represents one of the hallmarks of all chronic diseases, including cancer, and was already investigated as a prognostic marker in the pre-immunotherapy era. Sarcopenia can be evaluated using cross-sectional image analysis of CT-scans, at the level of the third lumbar vertebra (L3), to estimate the skeletal muscle index (SMI), a surrogate of skeletal muscle mass, and to evaluate the skeletal muscle density (SMD). We performed a retrospective analysis of consecutive advanced cancer patient treated with PD-1/PD-L1 checkpoint inhibitors. Baseline SMI and SMD were evaluated and optimal cut-offs for survival, according to sex and BMI (+/−25) were computed. The evaluated clinical outcomes were: objective response rate (ORR), immune-related adverse events (irAEs), progression free survival (PFS) and overall survival (OS). From April 2015 to April 2019, 100 consecutive advanced cancer patients were evaluated. 50 (50%) patients had a baseline low SMI, while 51 (51%) had a baseline low SMD according to the established cut offs. We found a significant association between SMI and ECOG-PS (p = 0.0324), while no correlations were found regarding SMD and baseline clinical factors. The median follow-up was 20.3 months. Patients with low SMI had a significantly shorter PFS (HR = 1.66 [95% CI: 1.05–2.61]; p = 0.0291) at univariate analysis, but not at the multivariate analysis. They also had a significantly shorter OS (HR = 2.19 [95% CI: 1.31–3.64]; p = 0.0026). The multivariate analysis confirmed baseline SMI as an independent predictor for OS (HR = 2.19 [1.31–3.67]; p = 0.0027). We did not find significant relationships between baseline SMD and clinical outcomes, nor between ORR, irAEs and baseline SMI (data not shown). Low SMI is associated with shortened survival in advanced cancer patients treated with PD1/PDL1 checkpoint inhibitors. However, the lack of an association between SMI and clinical response suggests that sarcopenia may be generally prognostic in this setting rather than specifically predictive of response to immunotherapy.

Associations between Handgrip Strength with Adverse Cardiometabolic Health among Representative Korean Adults

Reduced muscle mass and strength are notable features of aging. Loss of muscle mass contributes to cardiometabolic health. Although many studies have focused on skeletal muscle mass, it remains unclear whether muscle strength is beneficial for cardiometabolic health. We aimed to investigate the association between handgrip strength and the risk of adverse cardiometabolic health in middle-aged and older adults in the Korean general population. The study participants included 7602 adults from the Korea National Health and Nutritional Examination Survey (KNHANES). The odds ratio for adverse cardiometabolic health significantly and linearly decreased according to the category of handgrip strength adjusted for potential confounding factors (p-Value < 0.05). In the stratified models by sex we also observed significant associations between handgrip strength and cardiometabolic health in men (p-Value < 0.001), but not in women. Our findings suggest that maintaining higher handgrip strength may contribute to improved cardiometabolic health.

Differences in frailty in older men and women

Frailty describes an individual's vulnerability to adverse health outcomes and is a useful construct that assists health professionals to understand the heterogeneity of the ageing population. While the pathophysiological pathways that lead to frailty are not well defined, an individual's sex appears to be a key factor influencing the ageing trajectory. Compared with age-matched men, women tend to have poorer health status (ie, they are more frail) but longer life expectancy (ie, they are more resilient). It seems likely that a combination of biological, behavioural and social factors underpin this male-female health-survival paradox. Randomised controlled trial data for frailty interventions in older adults are emerging, with multicomponent programs incorporating exercise and nutrition-based strategies showing promise. Pharmaceutical and other innovative therapeutic strategies for frailty are highly anticipated. Sex differences in the effectiveness of frailty interventions have not been addressed in the research literature to date. In the future, successful interventions may target many (if not all) biopsychosocial domains, with careful consideration of issues relevant to each sex.

Sleep duration and sarcopenia risk: a systematic review and dose-response meta-analysis

PURPOSE

Present systematic literature review and dose-response meta-analysis were carried out to evaluate the association between sleep duration and sarcopenia risk.

METHODS

Related studies were found by searching ISI Web of science databases, Scopus, and PubMed, up to May, 2019. Data were available from four studies. A total odds ratio of 17551 participants in these studies was pooled for the current study.

RESULTS

Pooled outcomes from random effects model demonstrated that lowest category of sleep duration (under 6 h) versus reference category (6-8 h) was significantly related with increased risk of sarcopenia (OR: 1.71 95% CI, 1.11, 2.64). Pooled OR also indicated that highest category (more than 8 h) of sleep duration versus reference category (6-8 h) was significantly associated with increased risk of sarcopenia (OR: 1.52 95% CI, 1.23, 1.88). Moreover, subgroup analysis by sex showed that women were affected by both short and long sleep while men were only affected by long sleep duration. The nonlinear dose-response meta-analysis revealed a U-shaped association between sleep duration and the risk of sarcopenia, with a nadir at 8 h per day. The linear dose-response meta-analysis illustrated that the risk of sarcopenia did not change significantly nor for a 0.5-h increment neither for 1-h increment in sleep duration per day.

CONCLUSION

The outcomes from this meta-analysis indicate that the public should be made aware of the negative consequences of long and short sleep for sarcopenia especially among women. Further studies should now be undertaken to establish possible links between risk of sarcopenia and sleep duration.

Body Composition and Biochemical Markers of Nutrition in Non-dialysis-Dependent Chronic Kidney Disease Patients

The aim of this study was to examine the body composition in stages 3b to 5 of chronic kidney disease. There were 149 patients included in the study, with the mean age of 65.5 ± 16.5 years, body mass index (BMI) of 29.4 ± 5.6 kg/m², and estimated glomerular filtration rate (eGFR) of 23.2 ± 9.3/min/1.73m². They remained with dialysis. Body composition was measured using bioimpedance spectroscopy, and handgrip strength was measured with a hydraulic dynamometer. The main biochemical markers assessed consisted of serum protein, albumin, prealbumin, high-sensitivity C-reactive protein (hsCRP), and interleukin (IL)-6 content. We found that 39% of patients were overweight and 41% were obese. Obesity was more prevalent in stage 3b of chronic kidney disease than in stages 4-5 in women and in patients older than 60 years of age. Thirty-eight percent of the study population were sarcopenic, of whom 20% presented a sarcopenic obesity phenotype. There were significant associations between lean tissue index (LTI) and serum prealbumin content and handgrip strength. Fat tissue index (FTI) was associated and hsCRP, serum protein, body mass index (BMI), waist-hip ratio, and waist-to-height ratio. There were inverse associations between FTI-LTI and LTI-age. We conclude that the prevalence of obesity in non-dialysis-dependent patients with chronic kidney disease is higher than that in the general population. Earlier stages of chronic kidney disease are associated with a higher prevalence of obesity.

A sex-specific evaluation of predicted lean and fat mass composition and cardiovascular disease onset and progression: A combined analysis of the ATTICA and GREECS prospective epidemiological studies

OBJECTIVES

To evaluate the association of predicted lean and fat mass on 10-year first and recurrent CVD incidence separately for men and women.

METHODS

Two prospective studies, ATTICA (2002-2012, n=3042 subjects free-of-CVD, n=1514 men (46±13 years) and n=1528 women (45±14 years)) and GREECS (2004-2014, n=2172 subjects with acute coronary syndrome (ACS), n=1649 men (65±13 years) and n=523 women (62±11 years)) were used. Lean mass index (LMI) and fat mass index (FMI) were created through total body lean and fat mass (indirectly calculated through population formulas based on body weight, height and waist circumference) divided by height squared. Follow-up was performed in n=2020 of ATTICA (n=317 first CVD events) and in n=2172 patients of GREECS (n=811 recurrent CVD events).

RESULTS

In ATTICA study, CVD rate from 1st to 3rd FMI tertile was 9.4%, 16.1% and 19.9% while in GREECS 36.2%, 37.0%, 38.3%. The LMI-related rates were 17.1%, 15.0% and 11.9% vs. 38.8%, 35.8% and 36.7%. Multiadjusted analysis revealed U-shape trend between LMI and CVD recurrence with 2nd LMI tertile having the best prognosis; this observation was more evident in women. In apparently healthy subjects, LMI-cardioprotective association was revealed only in 3rd tertile (HR=0.91 95%CI (0.74, 0.95)); this was more evident in men. The FMI aggravating association (3rd tertile) was retained significant only in healthy women and ACS men.

CONCLUSION

This work expands previous findings regarding body composition and cardiac health, implying that the association of lean and fat mass on long-term CVD incidence varies according to sex and prevention stage.

Sex Differences in Nonalcoholic Fatty Liver Disease: State of the Art and Identification of Research Gaps

Despite tremendous research advancements in nonalcoholic fatty liver disease (NAFLD), our understanding of sex differences in NAFLD remains insufficient. This review summarizes the current knowledge on sex differences in NAFLD, identifies gaps, and discusses important considerations for future research. The prevalence and severity of NAFLD are higher in men than in women during the reproductive age. However, after menopause, NAFLD occurs at a higher rate in women, suggesting that estrogen is protective. Sex differences also exist for the major risk factors of NAFLD. In general, animal models of NAFLD recapitulate the sex differences observed in patients, with more severe steatosis and steatohepatitis, more proinflammatory/profibrotic cytokines, and a higher incidence of hepatic tumors in male than female subjects. Based on computer modeling, female and male livers are metabolically distinct with unique regulators modulating sex-specific metabolic outcomes. Analysis of the literature reveals that most published clinical and epidemiological studies fail to examine sex differences appropriately. Considering the paucity of data on sex differences and the knowledge that regulators of pathways relevant to current therapeutic targets for NAFLD differ by sex, clinical trials should be designed to test drug efficacy and safety according to sex, age, reproductive stage (i.e., menopause), and synthetic hormone use. Conclusion: Sex differences do exist in the prevalence, risk factors, fibrosis, and clinical outcomes of NAFLD, suggesting that, while not yet incorporated, sex will probably be considered in future practice guidelines; adequate consideration of sex differences, sex hormones/menopausal status, age, and other reproductive information in clinical investigation and gene association studies of NAFLD are needed to fill current gaps and implement precision medicine for patients with NAFLD.

Differential response to targeted acupuncture by gender in patients with gastrointestinal cancer cachexia: secondary analysis of a randomized controlled trial

BACKGROUND

Cancer cachexia (CC) is a significant contributor to mortality and morbidity in patients with gastrointestinal (GI) cancer. Treatment options to prevent or halt the progression of CC are limited. Targeted acupuncture (TA) was used in GI patients with CC to evaluate for a potential gender effect.

PATIENTS AND METHODS

Participants (n = 30) were recruited from two outpatient clinics in the northern central part of Florida. All participants were diagnosed with CC and GI cancers. A randomized, single-blind, placebo-controlled clinical trial was used to compare TA to non-targeted acupuncture (NTA) over the course of 8 weeks. Primary endpoints were weight and body composition changes measured by bioelectrical impedance analysis (BIA) and biomarker analysis (tumor necrosis factor (TNF)-α and leptin). Herein, gender differences across and within TA and NTA groups were examined as a secondary analysis.

RESULTS

A significant (p = 0.026) interaction between weight and gender was noted, which manifested in a non-significant increase in the male intervention (MI) group, while TNF-α levels significantly increased by gender (p = 0.028) and group (p = 0.006) over the course of the study. All other groups either lost or did not change weight. The extracellular-to-intracellular water (ECW/ICW) ratio was significantly elevated for the TA group (p = 0.02) and for males (p = 0.009) at completion of the study. TNF-α and leptin levels were positively correlated within the MI group at the end of the study.

CONCLUSION

A decrease in leptin in the MI group corresponded to higher appetite and weight gain. The elevated ECW/ICW ratio indicates an inflammatory response in the MI group. This gender-specific response may be based on hormone-specific regulation of food intake. Further studies with larger sample sizes are required to support the results.

Skeletal Muscle Atrophy Was Alleviated by Salidroside Through Suppressing Oxidative Stress and Inflammation During Denervation

Skeletal muscle atrophy is a common and debilitating condition that lacks an effective therapy. Oxidative stress and inflammation are two main molecular mechanisms involved in muscle atrophy. In the current study, we want to explore whether and how salidroside, with antioxidant and anti-inflammatory properties, protects against skeletal muscle atrophy induced by denervation. First, oxidative stress and inflammatory response were examined during myotube atrophy induced by nutrition deprivation. The results demonstrated that oxidative stress and inflammatory response were induced in cultured myotubes suffered from nutrition deprivation, and salidroside not only inhibited oxidative stress and inflammatory response but also attenuated nutrition deprivation-induced myotube atrophy, as evidenced by an increased myotube diameter. The antioxidant, anti-inflammatory, and antiatrophic properties of salidroside in cultured myotubes were confirmed in denervated mouse models. The mice treated with salidroside showed less oxidative stress and less inflammatory cytokines, as well as higher skeletal muscle wet weight ratio and larger average cross sectional areas of myofibers compared with those treated with saline only during denervation-induced skeletal muscle atrophy. Moreover, salidroside treatment of denervated mice resulted in an inhibition of the activation of mitophagy in skeletal muscle. Furthermore, salidroside reduced the expression of atrophic genes, including MuRF1 and MAFbx, autophagy genes, including PINK1, BNIP3, LC3B, ATG7, and Beclin1, and transcription factor forkhead box O3 A (Foxo3A), and improved the expression of myosin heavy chain and transcriptional factor phosphorylated Foxo3A. Taken together, these results suggested that salidroside alleviated denervation-induced muscle atrophy by suppressing oxidative stress and inflammation.

Muscle metabolism and atrophy: let's talk about sex

Skeletal muscle health is a strong predictor of overall health and longevity. Pathologies affecting skeletal muscle such as cancer cachexia, intensive care unit treatment, muscular dystrophies, and others are associated with decreased quality of life and increased mortality. Recent research has begun to determine that these muscular pathologies appear to present and develop differently between males and females. However, to our knowledge, there has yet to be a comprehensive review on musculoskeletal differences between males and females and how these differences may contribute to sex differences in muscle pathologies. Herein, we present a review of the current literature on muscle phenotype and physiology between males and females and how these differences may contribute to differential responses to atrophic stimuli. In general, females appear to be more susceptible to disuse induced muscle wasting, yet protected from inflammation induced (such as cancer cachexia) muscle wasting compared to males. These differences may be due in part to differences in muscle protein turnover, satellite cell content and proliferation, hormonal interactions, and mitochondrial differences between males and females. However, more works specifically examining muscle pathologies in females are necessary to more fully understand the inherent sex-based differences in muscle pathologies between the sexes and how they may correspond to different clinical treatments.

Cancer-driven changes link T cell frequency to muscle strength in people with cancer: a pilot study

BACKGROUND

Tumour growth can promote the loss of muscle mass and function. This is particularly disturbing because overall survival is significantly reduced in people with weaker and smaller skeletal muscle. The risk of cancer is also greater in people who are immune deficient. Muscle wasting in mice with cancer can be inhibited by infusion of CD4⁺ precursor T cells that restore balanced ratios of naïve, memory, and regulatory T cells. These data are consistent with the hypothesis that stronger anti-cancer T cell immunity leads to improved muscle mass and function. As a first step to testing this hypothesis, we determined whether levels of circulating T cell subsets correlate with levels of muscle strength in people with cancer.

METHODS

The frequency of circulating CD4⁺ and CD8⁺ naïve, memory, and regulatory T cell subsets was quantified in 11 men with gastrointestinal cancer (aged 59.3 ± 10.1 years) and nine men without cancer (aged 60 ± 13 years), using flow cytometry. T cell marker expression was determined using real-time PCR and western blot analyses in whole blood and peripheral blood mononuclear cells. Handgrip strength, one-repetition maximum chest press, and knee extension tests were used to determine muscle strength. Performance was determined using a stair climb test. Body composition was determined using dual-energy X-ray absorptiometry scan. The Karnofsky and ECOG scales were used to assess functional impairment. Correlations between frequencies of cell subsets with strength, performance, and body composition were determined using regression analyses.

RESULTS

Our data show significant correlations between (i) higher frequencies of CD8⁺ naïve (P = 0.02) and effector memory (P = 0.003) T cells and lower frequencies of CD8⁺ central memory T cells (P = 0.002) with stronger handgrip strength, (ii) lower frequency of regulatory cells with greater lean mass index (P = 0.04), (iii) lower frequency of CD8⁺ T cells that express CD95 with greater stair climb power (P = 0.003), (iv) higher frequency of T cells that co-express CD197 and CD45RA and greater one-repetition maximum knee extension strength (P = 0.008), and (iv) higher expression of CD4 in whole blood with greater functional impairment (P = 0.004) in people with cancer.

CONCLUSIONS

We have identified significant correlations between levels of T cell populations and muscle strength, performance, and body composition in people with cancer. These data justify a follow-up study with a larger cohort to test the validity of the findings.

Skeletal muscle mass in acute coronary syndrome prognosis: Gender-based analysis from Hellenic Heart Failure cohort

BACKGROUND AND AIMS

Predictive and prognostic ability of muscle mass in CVD settings is increasingly discussed. The gender-specific effect of skeletal muscle mass index (SMI) on 10-year recurrent fatal/non fatal cardiovascular disease (CVD) event of acute coronary syndrome (ACS) patients was evaluated.

METHODS AND RESULTS

In 2006-2009, n = 1000 consecutive patients (n = 222 women), hospitalized at the First Cardiology Clinic of Athens with ACS diagnosis and with symptoms and left ventricular function indicative of heart failure were selected. SMI was created to reflect skeletal muscle mass through appendicular skeletal muscle mass (indirectly calculated through population formulas) divided by body mass index (BMI). In the 10-year follow-up (2016), 55% of ACS patients experienced recurrent fatal/non fatal CVD events (53% in women vs.62% in men, p = 0.04). Patients in the 2nd SMI tertile (mostly overweight) had 10% lower risk for CVD recurrence (women:men rate ratio = 0.87) over their counterparts in the 1st (mostly normalweight) and 3rd tertile (mostly obese). Multivariate analysis revealed that ACS patients in the 2nd SMI tertile presented 46% and 85% lower CVD event risk over their counterparts in the 1st tertile (Hazard Ratio (HR) = 0.54, 95% Confidence Interval (95% CI) 0.30, 0.96, p = 0.002) and 3rd tertile (HR = 1.85, 95%CI 1.05, 2.94, p = 0.03). Gender-based analysis revealed that this trend remained significant only in women. Inflammatory markers had strong confounding effect.

CONCLUSION

A U-shape association between SMI and 10-year CVD event especially in women was highlighted. This work reveals gender-specific remarks for "obesity-lean paradox" in secondary prevention, implying that high muscle mass accompanied by obesity and excess adiposity may not guarantee better prognosis.

Prevention and Treatment of Sarcopenic Obesity in Women

Sarcopenic obesity (SO) is referred to as the combination of obesity with low skeletal muscle mass and function. However, its definition and diagnosis is debated. SO represents a sizable risk factor for the development of disability, possibly with a worse prognosis in women. The present narrative review summarizes the current evidence on pharmacological, nutrition and exercise strategies on the prevention and/or treatment of SO in middle-aged and older-aged women. A literature search was carried out in Medline and Google Scholar between 29th January and 14th March 2019. Only controlled intervention studies on mid-age and older women whose focus was on the prevention and/or treatment of sarcopenia associated with obesity were included. Resistance training (RT) appears effective in the prevention of all components of SO in women, resulting in significant improvements in muscular mass, strength, and functional capacity plus loss of fat mass, especially when coupled with hypocaloric diets containing at least 0.8 g/kg body weight protein. Correction of vitamin D deficit has a favorable effect on muscle mass. Treatment of SO already established is yet unsatisfactory, although intense and prolonged RT, diets with higher (1.2 g/kg body weight) protein content, and soy isoflavones all look promising. However, further confirmatory research and trials combining different approaches are required.

Aging of the musculoskeletal system: How the loss of estrogen impacts muscle strength

Skeletal muscle weakness occurs with aging and in females this is compounded by the loss of estrogen with ovarian failure. Estrogen deficiency mediates decrements in muscle strength from both inadequate preservation of skeletal muscle mass and decrements in the quality of the remaining skeletal muscle. Processes and components of skeletal muscle that are affected by estrogens are beginning to be identified. This review focuses on mechanisms that contribute to the loss of muscle force generation when estrogen is low in females, and conversely the maintenance of strength by estrogen. Evidence is accumulating that estrogen deficiency induces apoptosis in skeletal muscle contributing to loss of mass and thus strength. Estrogen sensitive processes that affect quality, i.e., force generating capacity of muscle, include myosin phosphorylation and satellite cell function. Further detailing these mechanisms and identifying additional mechanisms that underlie estrogenic effects on skeletal muscle is important foundation for the design of therapeutic strategies to minimize skeletal muscle pathologies, such as sarcopenia and dynapenia.

Association between Sarcopenia and Depression in Patients with Chronic Liver Diseases

Association between sarcopenia, as evaluated by grip strength (GS) and skeletal muscle mass (SMM), and depression, as evaluated by Beck Depression Inventory-2nd edition (BDI-II) in chronic liver diseases (CLDs, n = 414, average age = 61.5 years), was investigated. Study subjects were classified into four groups: Group A (n = 60), lower GS and lower SMM (sarcopenia); group B (n = 44), lower GS and higher SMM; group C (n = 100), higher GS and lower SMM; group D (n = 210), higher GS and higher SMM. Factors associated with BDI-II score ≥11 were examined. BDI-II score 0–10 (normal) was found in 284 (68.6%), 11–16 (minimal) in 76 (18.4%), 17–20 (mild) in 24 (5.8%), 21–30 (moderate) in 15 (3.6%), and ≥31 (severe) in 15 (3.6%). The average ± standard deviation BDI-II score in liver cirrhosis (LC) patients (10.2 ± 9.6, n = 152) was significantly higher than that in non-LC patients (7.4 ± 7.2, n = 262) (p = 0.0058). Univariate analysis identified three factors to be significantly associated with BDI-I score ≥11: Our classification (groups of A, B, C, and D) (p = 0.0259), serum albumin (p = 0.0445), and the presence of LC (p = 0.0157). Multivariate analysis revealed that only group A (p = 0.0074, group D as a reference) was significant. In conclusion, sarcopenia can be an independent predictor for depression in CLDs.

Factors Contributing to Cancer-Related Muscle Wasting During First-Line Systemic Treatment for Metastatic Colorectal Cancer

Background

Increasing evidence indicates that loss of muscle mass is associated with adverse outcomes in metastatic colorectal cancer. Here, we investigate which demographic, lifestyle- (smoking), tumor-, and treatment-related factors are associated with muscle loss in patients with metastatic colorectal cancer during first-line palliative systemic treatment.

Methods

Data from 300 patients with computed tomography scans both at start and after six initial cycles of capecitabine plus oxaliplatin and bevacizumab was used (CAIRO3). From computed tomography, muscle mass normalized for stature (skeletal muscle index [SMI]) was calculated. A priori-selected variables were tested using multivariable linear regression models (P values ≤.05). Two models were developed: Model 1 contained variables measured at start and Model 2 contained variables assessed after initial therapy.

Results

In Model 1, loss of SMI was statistically significantly associated with a higher initial SMI (−0.32%, 95% confidence interval [CI] = −0.45% to −0.19% per unit increase in initial SMI), smoking status (−2.74%, 95% CI = −5.29% to −0.19% for smokers), and interval of metastases (−3.02%, 95% CI = −5.50% to −0.53%) for metachronous vs synchronous metastases), and primary tumor resection was statistically significantly associated with a gain in SMI (2.17%, 95% CI = 0.13% to 4.21% for resection vs no resection). In Model 2, loss of SMI was statistically significantly associated with response to capecitabine plus oxaliplatin and bevacizumab (−2.48%, 95% CI = −4.33% to −0.62% for stable disease vs partial/complete response).

Conclusions

Our results highlight, given the association of sarcopenia and survival, that patients with higher SMI should not be ignored. In addition, smoking is a potentially modifiable factor associated with muscle loss. The association between smoking and muscle loss might relate to worse clinical outcomes in smokers with metastatic colorectal cancer.

Dietary Patterns, Skeletal Muscle Health, and Sarcopenia in Older Adults

In recent decades, the significance of diet and dietary patterns (DPs) for skeletal muscle health has been gaining attention in ageing and nutritional research. Sarcopenia, a muscle disease characterised by low muscle strength, mass, and function is associated with an increased risk of functional decline, frailty, hospitalization, and death. The prevalence of sarcopenia increases with age and leads to high personal, social, and economic costs. Finding adequate nutritional measures to maintain muscle health, preserve function, and independence for the growing population of older adults would have important scientific and societal implications. Two main approaches have been employed to study the role of diet/DPs as a modifiable lifestyle factor in sarcopenia. An a priori or hypothesis-driven approach examines the adherence to pre-defined dietary indices such as the Mediterranean diet (MED) and Healthy Eating Index (HEI)—measures of diet quality—in relation to muscle health outcomes. A posteriori or data-driven approaches have used statistical tools—dimension reduction methods or clustering—to study DP-muscle health relationships. Both approaches recognise the importance of the whole diet and potential cumulative, synergistic, and antagonistic effects of foods and nutrients on ageing muscle. In this review, we have aimed to (i) summarise nutritional epidemiology evidence from four recent systematic reviews with updates from new primary studies about the role of DPs in muscle health, sarcopenia, and its components; (ii) hypothesise about the potential mechanisms of ‘myoprotective’ diets, with the MED as an example, and (iii) discuss the challenges facing nutritional epidemiology to produce the higher level evidence needed to understand the relationships between whole diets and healthy muscle ageing.

Differences in Respiratory Muscle Strength Measures in Well-Nourished and Malnourished Hospitalized Patients

BACKGROUND

Objective indicators of nutritional status are essential for accurate identification of malnutrition. Previous research has indicated an association between measures of respiratory muscle strength (RMS) and nutritional status. Measurement of RMS-including maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP)-may provide evidence to support the assessment of nutritional status in hospitalized patients.

OBJECTIVE

The purpose of this study was to determine whether there was a difference in MIP, MEP, and SNIP between well-nourished and malnourished hospitalized patients.

DESIGN

A cross-sectional study was conducted.

PARTICIPANTS/SETTING

Patients were screened for eligibility criteria on admission by means of electronic medical records in general medical or surgical units at a tertiary care hospital in Chicago, IL, from January 2016 to January 2017. A total of 140 patients were included for analysis.

MAIN OUTCOMES MEASURED

The primary outcome was detection of differences in measures of RMS between malnourished and well-nourished hospitalized patients. Nutritional status was assessed using subjective global assessment and Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition (Academy/ASPEN) criteria recommended to identify malnutrition. The MIP, MEP, and SNIP measures were obtained and reported as absolute values (expressed in centimeters of water) and percent of predicted values.

STATISTICAL ANALYSIS

Independent t tests or Mann-Whitney U tests were used to determine differences in RMS measures between patients assessed as well nourished and those assessed as malnourished, depending on normality.

RESULTS

Compared with well-nourished patients, malnourished patients identified by subjective global assessment criteria had significantly lower absolute SNIP (73.7±28.7 vs 59.5±27.1 cm H₂O, P=0.004) and percent of predicted SNIP (78.6%±26.3% vs 64.8%± 30.0% predicted, P=0.006). Similarly, compared with well-nourished patients when Academy/ASPEN guidelines were used, malnourished individuals had significantly lower absolute SNIP (76.5±28.6 vs 58.3±26.3 cm H₂O, P<0.001), percent of predicted SNIP (81.4%±26.4% vs 63.5%±28.7% predicted, P<0.001), absolute MIP (83.5±34.6 vs 71.1±33.6 cm H₂O, P=0.05), and absolute MEP (108.7±36.6 vs 94.2±39.9 cm H₂O, P=0.04).

CONCLUSION

Differences in RMS between well-nourished and malnourished patients were observed when SNIP measures were used. However, there were no differences in MIP and MEP measures. Further research is needed to build on the findings from this study.

Effect of Sarcopenia on Sleep Disturbance in Patients with Chronic Liver Diseases

We sought to investigate the influence of sarcopenia as defined by muscle strength and skeletal muscle mass (SMM) on sleep disturbance as evaluated by the Japanese version of Pittsburgh Sleep Quality Index (PSQI-J) in chronic liver diseases (CLDs) (n = 419). Muscle strength and muscle mass were determined by grip strength (GS) and SMM using bioimpedance analysis. Patients were classified into four types: type A (n = 61); decreased GS and decreased SMM; type B (n = 45); decreased GS and non-decreased SMM; type C (n = 102); non-decreased GS and decreased SMM; and type D (n = 211); non-decreased GS and non-decreased SMM. Factors associated with PSQI-J score 6 or more were examined. PSQI-J score 0–5 (normal) was found in 253 (60.4%); 6–8 (mild) in 97 (23.2%); 9–11 (moderate) in 45 (10.7%) and 12 or more (severe) in 24 (5.7%). Univariate analysis identified three factors to be significantly associated with PSQI-J score 6 or more: presence of liver cirrhosis (LC) (P = 0.0132); our classification of type A; B; C and D (P < 0.0001) and serum albumin level (P = 0.0041). Multivariate analysis showed that type A (P = 0.0021) and type B (P = 0.0220) were significant independent factors. In conclusion, sarcopenia in CLDs appears to be closely associated with sleep disturbance mainly due to muscle strength decline.

Human Breast Cancer Xenograft Model Implicates Peroxisome Proliferator-activated Receptor Signaling as Driver of Cancer-induced Muscle Fatigue

PURPOSE

This study tested the hypothesis that a patient-derived orthotopic xenograft (PDOX) model would recapitulate the common clinical phenomenon of breast cancer-induced skeletal muscle (SkM) fatigue in the absence of muscle wasting. This study additionally sought to identify drivers of this condition to facilitate the development of therapeutic agents for patients with breast cancer experiencing muscle fatigue.

EXPERIMENTAL DESIGN

Eight female BC-PDOX-bearing mice were produced via transplantation of tumor tissue from 8 female patients with breast cancer. Individual hind limb muscles from BC-PDOX mice were isolated at euthanasia for RNA-sequencing, gene and protein analyses, and an ex vivo muscle contraction protocol to quantify tumor-induced aberrations in SkM function. Differentially expressed genes (DEG) in the BC-PDOX mice relative to control mice were identified using DESeq2, and multiple bioinformatics platforms were employed to contextualize the DEGs.

RESULTS

We found that SkM from BC-PDOX-bearing mice showed greater fatigability than control mice, despite no differences in absolute muscle mass. PPAR, mTOR, IL6, IL1, and several other signaling pathways were implicated in the transcriptional changes observed in the BC-PDOX SkM. Moreover, 3 independent in silico analyses identified PPAR signaling as highly dysregulated in the SkM of both BC-PDOX-bearing mice and human patients with early-stage nonmetastatic breast cancer.

CONCLUSIONS

Collectively, these data demonstrate that the BC-PDOX model recapitulates the expected breast cancer-induced SkM fatigue and further identify aberrant PPAR signaling as an integral factor in the pathology of this condition.

Health-Related Quality of Life in Chronic Liver Diseases: A Strong Impact of Hand Grip Strength

We sought to examine the influence of hand grip strength (HGS) and skeletal muscle mass (SMM) on the health-related quality of life (H-QOL) as evaluated by the 36-Item Short-Form Health Survey (SF-36) questionnaire in chronic liver diseases (CLDs, 198 men and 191 women). Decreased HGS was defined as HGS <26 kg for men and <18 kg for women. Decreased SMM was defined as SMM index <7.0 kg/m² for men and <5.7 kg/m² for women, using bioimpedance analysis. SF-36 scores were compared between groups stratified by HGS or SMM. Between-group differences (decreased HGS vs. non-decreased HGS) in the items of physical functioning (PF), role physical (RP), bodily pain, vitality (VT), social functioning (SF), role emotional (RE), and physical component summary score (PCS) reached significance, while between-group differences (decreased SMM vs. non-decreased SMM) in the items of PF, SF and RE were significant. Multivariate analyses revealed that HGS was significantly linked to PF (p = 0.0031), RP (p = 0.0185), and PCS (p = 0.0421) in males, and PF (p = 0.0034), VT (p = 0.0150), RE (p = 0.0422), and PCS (p = 0.0191) in females. HGS had a strong influence especially in the physiological domains in SF-36 in CLDs.

Understanding sex differences in the regulation of cancer-induced muscle wasting

PURPOSE OF REVIEW

We highlight evidence for sexual dimorphism in preclinical and clinical studies investigating the cause and treatment of cancer cachexia.

RECENT FINDINGS

Cancer cachexia is unintended bodyweight loss occurring with cancer, and skeletal muscle wasting is a critical predictor of negative outcomes in the cancer patient. Skeletal muscle exhibits sexual dimorphism in fiber type, function, and regeneration capacity. Sex differences have been implicated in skeletal muscle metabolism, mitochondrial function, immune response to injury, and myogenic stem cell regulation. All of these processes have the potential to be involved in cancer-induced muscle wasting. Unfortunately, the vast majority of published studies examining cancer cachexia in preclinical models or cancer patients either have not accounted for sex in their design or have exclusively studied males. Preclinical studies have established that ovarian function and estradiol can affect skeletal muscle function, metabolism and mass; ovarian function has also been implicated in the sensitivity of circulating inflammatory cytokines and the progression of cachexia.

SUMMARY

Females and males have unique characteristics that effect skeletal muscle's microenvironment and intrinsic signaling. These differences provide a strong rationale for distinct causes for cancer cachexia development and treatment in males and females.

Muscle and Bone Health in Postmenopausal Women: Role of Protein and Vitamin D Supplementation Combined with Exercise Training

Menopause is an age-dependent physiological condition associated with a natural decline in oestrogen levels, which causes a progressive decrease of muscle mass and strength and bone density. Sarcopenia and osteoporosis often coexist in elderly people, with a prevalence of the latter in elderly women. The profound interaction between muscle and bone induces a negative resonance between the two tissues affected by these disorders worsening the quality of life in the postmenopausal period. It has been estimated that at least 1 in 3 women over age 50 will experience osteoporotic fractures, often requiring hospitalisation and long-term care, causing a large financial burden to health insurance systems. Hormonal replacement therapy is effective in osteoporosis prevention, but concerns have been raised with regard to its safety. On the whole, the increase in life expectancy for postmenopausal women along with the need to improve their quality of life makes it necessary to develop specific and safe therapeutic strategies, alternative to hormonal replacement therapy, targeting both sarcopenia and osteoporosis progression. This review will examine the rationale and the effects of dietary protein, vitamin D and calcium supplementation combined with a specifically-designed exercise training prescription as a strategy to counteract these postmenopausal-associated disorders.

Chemotherapy-induced muscle wasting: an update

The majority of cancers are associated to cachexia, a severe form of weight loss mostly accounted for by skeletal muscle wasting. Cancer patients are often treated with chemotherapy, whose side effects are at times neglected or underestimated. Paradoxically, chemotherapy itself can induce muscle wasting with severe, cancer-independent effects on muscle homeostasis. Since muscle wasting is a primary marker of poor prognosis for cancer patients and negatively affects their quality of life, the systemic consequences of chemotherapy in this context must be fully characterized and taken into account. Ten years ago a precursor study in an animal cancer model was published in the European Journal of Translation Myology (back then, Basic and Applied Myology), highlighting that the side effects of chemotherapy include muscle wasting, possibly mediated by NF-κB activation. This paper, entitled «Chemotherapy-induced muscle wasting: association with NF-κB and cancer cachexia», is now being reprinted for the inaugural issue of the «Ejtm Seminal Paper Series». In this short review we discuss those results in the light of the most recent advances in the study of chemotherapy-induced muscle wasting.

Muscle Atrophy in Chronic Kidney Disease

The renal damage and loss of kidney function that characterize chronic kidney disease (CKD) cause several complex systemic alterations that affect muscular homeostasis, leading to loss of muscle mass and, ultimately, to muscle atrophy. CKD-induced muscle atrophy is highly prevalent and, in association with common CKD comorbidities, is responsible for the reduction of physical capacity, functional independence, and an increase in the number of hospitalizations and mortality rates. Thus, this chapter summarizes current knowledge about the complex interactions between CKD factors and the pathophysiological mechanisms that induce muscle atrophy that, despite growing interest, are not yet fully understood. The current treatments of CKD-induced muscle atrophy are multidisciplinary, including correction of metabolic acidosis, nutritional supplementation, reducing insulin resistance, administration of androgenic steroids, resisted and aerobic exercise, neuromuscular electrical stimulation, and inspiratory muscle training. However, further studies are still needed to strengthen the comprehension of CKD-induced muscle atrophy and the better treatment strategies.