Sarcopenia: definition, epidemiology, and pathophysiology

Prognostic value of sarcopenia in patients with colorectal liver metastases undergoing hepatic resection

The prognostic significance of sarcopenia has been widely studied in different cancer patients. This study aimed to analyze the influence of sarcopenia on long-term survival in patients with colorectal liver metastasis (CRLM) undergoing hepatic resection. A retrospective analysis of 182 patients undergoing hepatic resection for CRLM was performed. Sarcopenia was determinedusing the Hounsfield unit average calculation (HUAC), a measure of muscle quality-muscledensity at preoperative abdominal computed tomography scans. Sarcopenia was defined as an HUAC score of less than 22 HU calculated using receiver operating characteristic analysis. The prognostic relevance of clinical variables and overall survival (OS) and recurrence-free survival (RFS) was evaluated. Patients with sarcopenia were older (p < 0.001) and had higher prevalence of diabetics (p = 0.004), higher body mass index (BMI) (p < 0.001) and neutrophil-to-lymphocyte ratio (p = 0.026) compared to those without. Sarcopenia was not significantly associated with OS and RFS. Multivariate Cox’s regression analysis showed that multinodularity (>3) (hazard ratio (HR) 2.736; 95% confidence interval (CI), 1.631–4.589; p < 0.001), high CEA level (≥20 ng/ml) (HR 1.793; 95% CI, 1.092–2.945; p = 0.021) and blood loss (≥300 cc) (HR1.793; 95% CI, 1.084–2.964; p = 0.023) were independent factors associated with OS. In subgroup analyses, sarcopenia was a significant factor of poor OS in the patients with multinodularity by univariate (p = 0.002) and multivariate analyses(HR 3.571; 95% CI, 1.508–8.403; p = 0.004). Multinodularity (>3) (HR 1.750; 95% CI, 1.066–2.872; p = 0.027), high aspartate aminotransferase level (HR 1.024; 95% CI, 1.003–1.046; p = 0.025) and male gender (HR 1.688; 95% CI, 1.036–2.748; p = 0.035) were independent factors of RFS. In conclusion, despite no significance in whole cohort, sarcopenia was predictive of worse OS in patients with multiple CRLM after partial hepatectomy.

Association between sarcopenia and levels of growth hormone and insulin-like growth factor-1 in the elderly

Background

Age-related sarcopenia is a serious global health issue in elderly individuals and for the community as it induces disability and significant economic burden. The purpose of the study is to understand the factors associated with sarcopenia and the role of growth hormone (GH) and insulin-like growth factor (IGF-1) in the occurrence of sarcopenia.

Methods

Elderly patients (n = 3276) were included in this cross-sectional study. Survey and measurement of body composition (bioelectrical impedance), grip strength, and step speed were performed according to the Asian Working Group on Sarcopenia (AWGS) diagnostic criteria. Hematological and hormonal indicators were compared between patients with and without sarcopenia in order to identify the associated factors.

Results

There were significant differences in the demographic parameters between the sarcopenia and non-sarcopenia groups (all P < 0.05). There were significant differences between the two groups regarding the blood levels of GH, IGF-1, testosterone (T), and mechanical growth factor (MGF) (all P < 0.001). Correlation analyses showed that the appendicular skeletal muscle mass (ASMI) was positively associated with gender and BMI, and with GH, T, IGF-1, MGF, BUN, Cr, and Hb levels, but negatively associated with HDL-C (all P < 0.05). Logistic multivariable regression analysis showed that IGF-1, MGF, BMI, and gender were independently associated with appendicular skeletal muscle mass (ASMI) (all P < 0.05).

Conclusions

GH and IGF-1 are associated with sarcopenia in the elderly. IGF-1 and MGF are independently associated with the reduction of skeletal muscle mass, along with BMI and gender.

Sarcopenia in patients with colorectal cancer: A comprehensive review

Colorectal cancer (CRC) is the third most commonly diagnosed cancer globally and the second cancer in terms of mortality. The prevalence of sarcopenia in patients with CRC ranges between 12%-60%. Sarcopenia comes from the Greek "sarx" for flesh, and "penia" for loss. Sarcopenia is considered a phenomenon of the aging process and precedes the onset of frailty (primary sarcopenia), but sarcopenia may also result from pathogenic mechanisms and that disorder is termed secondary sarcopenia. Sarcopenia diagnosis is confirmed by the presence of low muscle quantity or quality. Three parameters need to be measured: muscle strength, muscle quantity and physical performance. The standard method to evaluate muscle mass is by analyzing the tomographic total cross-sectional area of all muscle groups at the level of lumbar 3rd vertebra. Sarcopenia may negatively impact on the postoperative outcomes of patients with colorectal cancer undergoing surgical resection. It has been described an association between sarcopenia and numerous poor short-term CRC outcomes like increased perioperative mortality, postoperative sepsis, prolonged length of stay, increased cost of care and physical disability. Sarcopenia may also negatively impact on overall survival, disease-free survival, recurrence-free survival, and cancer-specific survival in patients with non-metastatic and metastatic colorectal cancer. Furthermore, patients with sarcopenia seem prone to toxic effects during chemotherapy, requiring dose deescalations or treatment delays, which seems to reduce treatment efficacy. A multimodal approach including nutritional support (dietary intake, high energy, high protein, and omega-3 fatty acids), exercise programs and anabolic-orexigenic agents (ghrelin, anamorelin), could contribute to muscle mass preservation. Addition of sarcopenia screening to the established clinical-pathological scores for patients undergoing oncological treatment (chemotherapy, radiotherapy or surgery) seems to be the next step for the best of care of CRC patients.

Phenotypes of Sarcopenic Obesity: Exploring the Effects on Peri-Muscular Fat, the Obesity Paradox, Hormone-Related Responses and the Clinical Implications

Sarcopenic obesity combines the words sarcopenia and obesity. This definition of obesity should be better differentiated between visceral and subcutaneous fat phenotypes. For this reason, this review lays the foundation for defining the subcutaneous and the visceral fat into the context of sarcopenia. Thus, the review aims to explore the missing links on pathogenesis of visceral fat and its relationship on age: defining the peri-muscular fat as a new entity and the subcutaneous fat as a first factor that leads to the obesity paradox. Last but not least, this review underlines and motivates the mechanisms of the hormonal responses and anti-inflammatory adipokines responsible for the clinical implications of sarcopenic visceral obesity, describing factor by factor the multiple axis between the visceral fat-sarcopenia and all mortality outcomes linked to cancer, diabetes, cardiovascular diseases, cirrhosis, polycystic ovary, disability and postoperative complications.

Examining Bone, Muscle and Fat in Middle-Aged Long-Term Endurance Runners: A Cross-Sectional Study

Aerobic exercise training has many known cardiovascular benefits that may promote healthy aging. It is not known if long-term aerobic exercise training is also associated with structural benefits (e.g., lower fat mass, higher areal bone mineral density (BMD) and greater muscle mass). We evaluated these parameters in middle-aged long-term endurance runners compared to sex-, age-, height-, and weight-matched non-running controls. Total and regional lean and fat mass and areal BMD were assessed by dual-energy X-ray absorptiometry. Sagittal magnetic resonance images captured the cross-sectional area and thickness of the lumbar multifidus. Runners (n = 10; all male) had a mean (standard deviation; SD) age of 49 (4) years, height of 178.9 (4.9) cm, weight of 67.8 (5.8) kg, body mass index (BMI) of 21.4 (1.4) kg/m² and had been running 82.6 (27.9) km/week for 23 (13) years. Controls (n = 9) had a mean (SD) age of 51 (5) years, height of 176.0 (5.1) cm, weight of 72.8 (7.1) kg, and BMI of 23.7 (2.1) kg/m². BMI was greater in controls (p = 0.010). When compared to controls on average, runners had a 10 percentage-point greater total body lean mass than controls (p = 0.001) and 14% greater trunk lean mass (p = 0.010), as well as less total body (8.6 kg; p < 0.001), arm (58%; p = 0.002), leg (52%; p < 0.001), trunk (73%; p < 0.001), android (91%; p < 0.001), and gynoid fat mass (64%; p < 0.001). No differences were observed between groups for BMD outcomes or multifidus size. These results underscore the benefits of endurance running to body composition that carry over to middle-age.

The Impact of Sarcopenia on Postoperative Course following Pancreatoduodenectomy: Single-Center Experience of 110 Consecutive Cases

BACKGROUND

Despite that mortality following pancreatoduodenectomy (PD) has gradually dropped during the past few decades, the incidence of postoperative complications remains high, ranging from 30-60%. Many studies have been focused on identification of perioperative risk factors for morbidity, and in recent years, sarcopenia has been pointed out as a valid predictor of postoperative complication.

MATERIALS AND METHODS

Perioperative data from 110 consecutive patients who underwent PD were retrieved, and the presence of sarcopenia was assessed by the measurement of Hounsfield unit average calculation on preoperative CT scans. Postoperative complications were graded according to Clavien-Dindo classification, and the morbidity burden was assessed by comprehensive complication index (CCI) calculation.

RESULTS

Sarcopenia was associated with advanced age (72 vs. 66 years; p = 0.014) and lower preoperative albumin levels (3.5 vs. 3.7 g/dL; p = 0.010); it represented an independent risk factor for clinically relevant complications (relative risk: 1.71; p = 0.015) and was related to a higher rate of Grade C postoperative pancreatic fistula (50.0 vs. 11.4%; p = 0.005) and a higher CCI (47.6 vs. 29.6; p = 0.001).

CONCLUSIONS

Sarcopenia represents a valid indicator of increased morbidity risk and may play a central role in preoperative risk stratification, allowing the selection of patients who may benefit from prehabilitation programs.

Mechanism of increased risk of insulin resistance in aging skeletal muscle

As age increases, the risk of developing type 2 diabetes increases, which is associated with senile skeletal muscle dysfunction. During skeletal muscle aging, mitochondrial dysfunction, intramyocellular lipid accumulation, increased inflammation, oxidative stress, modified activity of insulin sensitivity regulatory enzymes, endoplasmic reticulum stress, decreased autophagy, sarcopenia and over-activated renin-angiotensin system may occur. These changes can impair skeletal muscle insulin sensitivity and increase the risk of insulin resistance and type 2 diabetes during skeletal muscle aging. This review of the mechanism of the increased risk of insulin resistance during skeletal muscle aging will provide a more comprehensive explanation for the increased incidence of type 2 diabetes in elderly individuals, and will also provide a more comprehensive perspective for the prevention and treatment of type 2 diabetes in elderly populations.

Sarcopenic Obesity: Epidemiologic Evidence, Pathophysiology, and Therapeutic Perspectives

PURPOSE OF REVIEW

This review provides a comprehensive update on the definition, assessment, epidemiology, pathophysiology, clinical implications, and therapeutic approach of sarcopenic obesity (SO) and highlights the challenges, limitations, and knowledge gaps in SO research.

RECENT FINDINGS

The confluence of a rapidly aging population with rising obesity rates has led to the phenotype of SO, defined as the concurrent presence of sarcopenia and obesity. Despite efforts, a standardized definition of SO is still lacking. Its prevalence varies widely between studies, depending on population characteristics and different definitions. The major pathogenetic mechanisms include age-related changes in body composition and hormonal milieu, positive energy balance, pro-inflammatory pathways, and insulin resistance. Lifestyle interventions, including caloric restriction and physical activity, are the cornerstones of SO treatment. SO is a multifaceted syndrome with serious clinical implications. The development and implementation of effective prevention and treatment strategies is a top priority based on its dramatically increasing health impact.

Clinical insights into the kynurenine pathway in age-related diseases

Accumulating evidence from diverse experiments, including heterochronic parabiosis-the surgical joining of two animals of different ages-has highlighted the importance of systemic factors in the progressive functional decline of various organs and tissues during aging. The major metabolic pathway of tryptophan, an essential amino acid in humans, is the kynurenine pathway (KP) in which indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) catalyze the conversion of tryptophan into kynurenine. Importantly, circulating kynurenine produced by this enzymatic breakdown, as a primary driver of the aging process, has been linked to higher mortality in humans. This review discusses the potential roles of tryptophan derivatives as biomarkers for the risk of frailty in the elderly, based on human observational studies as well as the KP as a therapeutic target for age-related diseases.

Long-Term Moderate Exercise Combined with Metformin Treatment Induces an Hormetic Response That Prevents Strength and Muscle Mass Loss in Old Female Wistar Rats

Sarcopenia is a syndrome characterized by a progressive and generalized skeletal muscle mass and strength loss, as well as a poor physical performance, which as strongly been associated with aging. Sedentary lifestyle in the elderly contributes to this condition; however, physical activity improves health, reducing morbidity and mortality. Recent studies have shown that metformin (MTF) can also prevent muscle damage promoting muscular performance. To date, there is great controversy if MTF treatment combined with exercise training improves or nullifies the benefits provided by physical activity. This study is aimed at evaluating the effect of long-term moderate exercise combined with MTF treatment on body composition, strength, redox state, and survival rate during the life of female Wistar rats. In this study, rats performed moderate exercise during 20 of their 24 months of life and were treated with MTF for one year or for 6 months, i.e., from 12 to 24 months old and 18 to 24 months old. The body composition (percentage of fat, bone, and lean mass) was determined using a dual-energy X-ray absorption scanner (DXA), and grip strength was determined using a dynamometer. Likewise, medial and tibial nerve somatosensory evoked potentials were evaluated and the redox state was measured by HPLC, calculating the GSH/GSSG ratio in the gastrocnemius muscle. Our results suggest- that the MTF administration, both in the sedentary and the exercise groups, might activate a mechanism that is directly related to the induction of the hormetic response through the redox state modulation. MTF treatment does not eliminate the beneficial effects of exercise throughout life, and although MTF does not increase muscle mass, it increases longevity.

Altered Body Composition of Psoas and Thigh Muscles in Relation to Frailty and Severity of Parkinson's Disease

Background: To investigate the relationship between fat content and the cross-sectional area of psoas and thigh muscles, and clinical severity in patients with Parkinson’s disease. Materials and Methods: Twenty-five patients and 20 age- and sex-matched normal controls were recruited. All subjects underwent MRI study to determine the fat content of the bilateral psoas and thigh muscles. Muscle quality was measured by grasp, walking speed, and cross-sectional area. All patients underwent clinical surveys to evaluate disease severity and frailty, and analyses of the correlations between muscle quality and disease severity were performed. Results: Compared with the controls, patients exhibited higher fatty content in the measured muscles. The higher fat infiltration of measured muscles was significantly correlated with increased disease severity and frailty in patients. The fat fraction of the bilateral medial compartment of the thigh was correlated with the Unified Parkinson Disease Rating Scale-I results and the fat fraction of the bilateral anterior compartment of the thigh was correlated with weakness and exhaustion in patients. Conclusions: Decreased quality in psoas and thigh muscles is prominent in Parkinson’s disease which is further associated with disease severity and frailty. Awareness of the risk of sarcopenia and associated sequelae might improve patient care and outcomes.

The Degree of Aminoacidemia after Dairy Protein Ingestion Does Not Modulate the Postexercise Anabolic Response in Young Men: A Randomized Controlled Trial

BACKGROUND

Resistance exercise and dietary protein stimulate muscle protein synthesis (MPS). The rate at which proteins are digested and absorbed into circulation alters peak plasma amino acid concentrations and may modulate postexercise MPS. A novel mineral modified milk protein concentrate (mMPC), with identical amino acid composition to standard milk protein concentrate (MPC), was formulated to induce rapid aminoacidemia.

OBJECTIVES

The aim of this study was to determine whether rapid aminoacidemia and greater peak essential amino acid (EAA) concentrations induced by mMPC would stimulate greater postresistance exercise MPS, anabolic signaling, and ribosome biogenesis compared to standard dairy proteins, which induce a small but sustained plasma essential aminoacidemia.

METHODS

Thirty healthy young men (22.5 ± 3.0 y; BMI 23.8 ± 2.7 kg/m2) received primed constant infusions of l-[ring-13C6]-phenylalanine and completed 3 sets of leg presses and leg extensions at 80% of 1 repetition. Afterwards, participants were randomly assigned in a double-blind fashion to consume 25 g mMPC, MPC, or calcium caseinate (CAS). Vastus lateralis biopsies were collected at rest, and 2 and 4 h post exercise.

RESULTS

Plasma EAA concentrations, including leucine, were 19.2-26.6% greater in the mMPC group 45-90 min post ingestion than in MPC and CAS groups (P < 0.001). Myofibrillar fractional synthetic rate from baseline to 4 h was increased by 82.6 ± 64.8%, 137.8 ± 72.1%, and 140.6 ± 52.4% in the MPC, mMPC, and CAS groups, respectively, with no difference between groups (P = 0.548). Phosphorylation of anabolic signaling targets (P70S6KThr389, P70S6KThr421/Ser424, RPS6Ser235/236, RPS6Ser240/244, P90RSKSer380, 4EBP1) were elevated by <3-fold at both 2 and 4 h post exercise in all groups (P < 0.05).

CONCLUSIONS

The amplitude of plasma leucine and EAA concentrations does not modulate the anabolic response to resistance exercise after ingestion of 25 g dairy protein in young men. This trial was registered at http://www.anzctr.org.au/ as ACTRN12617000393358.

Regular Endurance Exercise Promotes Fission, Mitophagy, and Oxidative Phosphorylation in Human Skeletal Muscle Independently of Age

This study investigated whether regular endurance exercise maintains basal mitophagy and mitochondrial function during aging. Mitochondrial proteins and total mRNA were isolated from vastus lateralis biopsies (n = 33) of young sedentary (YS), old sedentary (OS), young active (YA), and old active (OA) men. Markers for mitophagy, fission, fusion, mitogenesis, and mitochondrial metabolism were assessed using qRT-PCR, Western blot, and immunofluorescence staining. Independently of age, fission protein Fis1 was higher in active vs. sedentary subjects (+80%; P < 0.05). Mitophagy protein PARKIN was more elevated in OA than in OS (+145%; P = 0.0026). mRNA expression of Beclin1 and Gabarap, involved in autophagosomes synthesis, were lower in OS compared to YS and OA (P < 0.05). Fusion and oxidative phosphorylation proteins were globally more elevated in the active groups (P < 0.05), while COx activity was only higher in OA than in OS (P = 0.032). Transcriptional regulation of mitogenesis did not vary with age or exercise. In conclusion, physically active lifestyle seems to participate in the maintenance of lifelong mitochondrial quality control by increasing fission and mitophagy.

Resilience among older cardiovascular disease patients with probable sarcopenia

AIM AND OBJECTIVES

The purpose of this study was to investigate the factors associated with resilience among probable sarcopenia older adults with cardiovascular disease.

INTRODUCTION

Resilience has been reported to be positively correlated with the mental health and physical functioning of older adults. Previous research has found that the development of resilience constitutes a form of compensation for loss of physical health. It is important for older adults, especially those with other underlying conditions, such as cardiovascular disease and sarcopenia, to have the ability to overcome adversity during the aging process. Thus, resilience becomes a critical characteristic in achieving a better life.

METHODS

A cross-sectional study design was used. A demographic questionnaire and the Chinese version of the Resilience Scale (CRS) were used to collect data. Multiple logistic regression was used to evaluate the predictors of low resilience.

RESULTS

A total of 267 participants were recruited, including 126 females and 141 males. Of the participants, 56% of their scores indicated low resilience. Income, education level, exercise time, primary caregiver, and having hypertension were the predictors of resilience.

CONCLUSION

The population with sarcopenia is increasing worldwide. Understanding resilience levels among older adults with probable sarcopenia is essential for promoting their mental health. Clinicians can use the results of this study to identify populations at high risk for low resilience and design specific interventions to promote better health outcomes.

Age-Related DNA Methylation Changes: Potential Impact on Skeletal Muscle Aging in Humans

Human aging is accompanied by a decline in muscle mass and muscle function, which is commonly referred to as sarcopenia. Sarcopenia is associated with detrimental clinical outcomes, such as a reduced quality of life, frailty, an increased risk of falls, fractures, hospitalization, and mortality. The exact underlying mechanisms of sarcopenia are poorly delineated and the molecular mechanisms driving the development and progression of this disorder remain to be uncovered. Previous studies have described age-related differences in gene expression, with one study identifying an age-specific expression signature of sarcopenia, but little is known about the influence of epigenetics, and specially of DNA methylation, in its pathogenesis. In this review, we will focus on the available knowledge in literature on the characterization of DNA methylation profiles during skeletal muscle aging and the possible impact of physical activity and nutrition. We will consider the possible use of the recently developed DNA methylation-based biomarkers of aging called epigenetic clocks in the assessment of physical performance in older individuals. Finally, we will discuss limitations and future directions of this field.

Deep learning-based muscle segmentation and quantification at abdominal CT: application to a longitudinal adult screening cohort for sarcopenia assessment

OBJECTIVE

To investigate a fully automated abdominal CT-based muscle tool in a large adult screening population.

METHODS

A fully automated validated muscle segmentation algorithm was applied to 9310 non-contrast CT scans, including a primary screening cohort of 8037 consecutive asymptomatic adults (mean age, 57.1±7.8 years; 3555M/4482F). Sequential follow-up scans were available in a subset of 1171 individuals (mean interval, 5.1 years). Muscle tissue cross-sectional area and attenuation (Hounsfield unit, HU) at the L3 level were assessed, including change over time.

RESULTS

Mean values were significantly higher in males for both muscle area (190.6±33.6 vs 133.3±24.1 cm², p<0.001) and density (34.3±11.1 HU vs 27.3±11.7 HU, p<0.001). Age-related losses were observed, with mean muscle area reduction of -1.5 cm²/year and attenuation reduction of -1.5 HU/year. Overall age-related muscle density (attenuation) loss was steeper than for muscle area for both sexes up to the age of 70 years. Between ages 50 and 70, relative muscle attenuation decreased significantly more in females (-30.6% vs -18.0%, p<0.001), whereas relative rates of muscle area loss were similar (-8%). Between ages 70 and 90, males lost more density (-22.4% vs -7.5%) and area (-13.4% vs -6.9%, p<0.001). Of the 1171 patients with longitudinal follow-up, 1013 (86.5%) showed a decrease in muscle attenuation, 739 (63.1%) showed a decrease in area, and 1119 (95.6%) showed a decrease in at least one of these measures.

CONCLUSION

This fully automated CT muscle tool allows for both individualized and population-based assessment. Such data could be automatically derived at abdominal CT regardless of study indication, allowing for opportunistic sarcopenia detection.

ADVANCES IN KNOWLEDGE

This fully automated tool can be applied to routine abdominal CT scans for prospective or retrospective opportunistic sarcopenia assessment, regardless of the original clinical indication. Mean values were significantly higher in males for both muscle area and muscle density. Overall age-related muscle density (attenuation) loss was steeper than for muscle area for both sexes, and therefore may be a more valuable predictor of adverse outcomes.

Sarcopenia and its association with falls and fractures in older adults: A systematic review and meta-analysis

Sarcopenia is a potentially modifiable risk factor for falls and fractures in older adults, but the strength of the association between sarcopenia, falls, and fractures is unclear. This study aims to systematically assess the literature and perform a meta-analysis of the association between sarcopenia with falls and fractures among older adults. A literature search was performed using MEDLINE, EMBASE, Cochrane, and CINAHL from inception to May 2018. Inclusion criteria were the following: published in English, mean/median age ≥ 65 years, sarcopenia diagnosis (based on definitions used by the original studies' authors), falls and/or fractures outcomes, and any study population. Pooled analyses were conducted of the associations of sarcopenia with falls and fractures, expressed in odds ratios (OR) and 95% confidence intervals (CIs). Subgroup analyses were performed by study design, population, sex, sarcopenia definition, continent, and study quality. Heterogeneity was assessed using the I² statistics. The search identified 2771 studies. Thirty-six studies (52 838 individuals, 48.8% females, and mean age of the study populations ranging from 65.0 to 86.7 years) were included in the systematic review. Four studies reported on both falls and fractures. Ten out of 22 studies reported a significantly higher risk of falls in sarcopenic compared with non-sarcopenic individuals; 11 out of 19 studies showed a significant positive association with fractures. Thirty-three studies (45 926 individuals) were included in the meta-analysis. Sarcopenic individuals had a significant higher risk of falls (cross-sectional studies: OR 1.60; 95% CI 1.37-1.86, P < 0.001, I²  = 34%; prospective studies: OR 1.89; 95% CI 1.33-2.68, P < 0.001, I²  = 37%) and fractures (cross-sectional studies: OR 1.84; 95% CI 1.30-2.62, P = 0.001, I²  = 91%; prospective studies: OR 1.71; 95% CI 1.44-2.03, P = 0.011, I²  = 0%) compared with non-sarcopenic individuals. This was independent of study design, population, sex, sarcopenia definition, continent, and study quality. The positive association between sarcopenia with falls and fractures in older adults strengthens the need to invest in sarcopenia prevention and interventions to evaluate its effect on falls and fractures.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Elderly

The Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Elderly was elaborated by nutritionists, nutrologists and hematologists physicians from 15 Brazilians reference centers in hematopoietic stem cell transplantation, in order to emphasize the importancy of nutritional status and the body composition during the treatment, as well as the main characteristics related to patient's nutritional assessment. Establishing the consensus, we intended to improve and standardize the nutritional therapy during the hematopoietic stem cell transplantation. The Consensus was approved by the Brazilian Society of Bone Marrow Transplantation.

Overweight in the Elderly Induces a Switch in Energy Metabolism that Undermines Muscle Integrity

Aging is characterized by a progressive loss of skeletal muscle mass and function (sarcopenia). Obesity exacerbates age-related decline and lead to frailty. Skeletal muscle fat infiltration increases with aging and seems to be crucial for the progression of sarcopenia. Additionally, skeletal muscle plasticity modulates metabolic adaptation to different pathophysiological situations. Thus, cellular bioenergetics and mitochondrial profile were studied in the skeletal muscle of overweight aged people without reaching obesity to prevent this extreme situation. Overweight aged muscle lacked ATP production, as indicated by defects in the phosphagen system, glycolysis and especially mostly by oxidative phosphorylation metabolic pathway. Overweight subjects exhibited an inhibition of mitophagy that was linked to an increase in mitochondrial biogenesis that underlies the accumulation of dysfunctional mitochondria and encourages the onset of sarcopenia. As a strategy to maintain cellular homeostasis, overweight subjects experienced a metabolic switch from oxidative to lactic acid fermentation metabolism, which allows continued ATP production under mitochondrial dysfunction, but without reaching physiological aged basal levels. This ATP depletion induced early signs of impaired contractile function and a decline in skeletal muscle structural integrity, evidenced by lower levels of filamin C. Our findings reveal the main effector pathways at an early stage of obesity and highlight the importance of mitochondrial metabolism in overweight and obese individuals. Exploiting mitochondrial profiles for therapeutic purposes in humans is an ambitious strategy for treating muscle impairment diseases.

Moderate-intensity aerobic exercise improves skeletal muscle quality in older adults

Sarcopenia, age-associated involuntary loss of muscle and strength, can progress to clinically relevant functional decline. Resistance exercise attenuates muscle and strength loss but may not be feasible for some older adults. Aerobic exercise training (AET) improves cardiopulmonary health; however, effects on protein turnover, muscle mass, and strength are less clear. We aimed to determine whether AET improves basal myofibrillar protein synthesis (MPS) and capillarization, promoting hypertrophy and strength. We hypothesized that AET improves strength with increased MPS and capillarization. Older adults were randomized to non-exercise (NON; n = 11, 71.4 ± 4.18 years) or exercise (EX; n = 12, 73.7 ± 4.05 years). EX completed 24 weeks of AET (walking 3×/week, 45 minutes, 70% heart rate reserve); NON remained sedentary. A stable isotope tracer was infused. MPS and capillarization were analyzed from vastus lateralis muscle biopsies. Strength was measured via isokinetic dynamometry. Lean mass was determined with dual-energy X-ray absorptiometry. Basal MPS increased in EX (+50.7%, P = 0.01) along with capillary density (+66.4%, P = 0.03), peak oxygen consumption (+15.8%, P = 0.01), quadriceps strength (+15.1%, P = 0.01), and muscle quality (peak torque divided by leg lean mass, +15.5%, P = 0.01). Lean mass did not change (P > 0.05). AET increases muscle protein turnover and capillarization in older adults, improving muscle quality.

Metabolic and Molecular Basis of Sarcopenia: Implications in the Management of Urothelial Carcinoma

Sarcopenia, which represents the degenerative and systemic loss of skeletal muscle mass, is a multifactorial syndrome caused by various clinical conditions. Sarcopenia reflects not only frailty and poor general health status, but also the possible presence of advanced or progressive cancer or cancer cachexia. Therefore, sarcopenia affects the management of cancer-bearing patients, including those with urothelial carcinoma. Recently, growing evidence has shown that sarcopenia is significantly associated with higher rates of treatment-related complications and worse prognosis in patients with urothelial carcinoma, including muscle-invasive bladder cancer, upper tract urothelial carcinoma, and advanced urothelial carcinoma. Moreover, several studies reported that a post-therapeutic increase in skeletal muscle mass predicts favorable prognosis in urothelial carcinoma patients. To further explore the role of sarcopenia in the management of urothelial carcinoma patients, comprehensive understanding of its pathophysiology is vital. In this article, we reviewed the metabolic and molecular basis of cancer cachexia and sarcopenia. From this viewpoint, we discussed the possible mechanism of changes in skeletal muscle mass during the course of treatment.

Mechanisms Underlying Metabolic Syndrome-Related Sarcopenia and Possible Therapeutic Measures

Although there are several reviews that report the interrelationship between sarcopenia and obesity and insulin resistance, the relation between sarcopenia and the other signs that compose the metabolic syndrome (MetS) has not been extensively revised. Here, we review the mechanisms underlying MetS-related sarcopenia and discuss the possible therapeutic measures proposed. A vicious cycle between the loss of muscle and the accumulation of intramuscular fat might be associated with MetS via a complex interplay of factors including nutritional intake, physical activity, body fat, oxidative stress, proinflammatory cytokines, insulin resistance, hormonal changes, and mitochondrial dysfunction. The enormous differences in lipid storage capacities between the two genders and elevated amounts of endogenous fat having lipotoxic effects that lead to the loss of muscle mass are discussed. The important repercussions of MetS-related sarcopenia on other illnesses that lead to increased disability, morbidity, and mortality are also addressed. Additional research is needed to better understand the pathophysiology of MetS-related sarcopenia and its consequences. Although there is currently no consensus on the treatment, lifestyle changes including diet and power exercise seem to be the best options.

Parkin overexpression protects from ageing-related loss of muscle mass and strength

KEY POINTS

Recent evidence suggests that impaired mitophagy, a process in charge of removing damaged/dysfunctional mitochondria and in part regulated by Parkin, could contribute to the ageing-related loss of muscle mass and function. In the present study, we show that Parkin overexpression attenuates ageing-related loss of muscle mass and strength and unexpectedly causes hypertrophy in adult skeletal muscles. We also show that Parkin overexpression leads to increases in mitochondrial content and enzymatic activities. Finally, our results show that Parkin overexpression protects from ageing-related increases in markers of oxidative stress, fibrosis and apoptosis. Our findings place Parkin as a potential therapeutic target to attenuate sarcopenia and improve skeletal muscle health and performance.

ABSTRACT

The ageing-related loss of muscle mass and strength, a process called sarcopenia, is one of the most deleterious hallmarks of ageing. Solid experimental evidence indicates that mitochondrial dysfunctions accumulate with ageing and are critical in the sarcopenic process. Recent findings suggest that mitophagy, the process in charge of the removal of damaged/dysfunctional mitochondria, is altered in aged muscle. Impaired mitophagy represents an attractive mechanism that could contribute to the accumulation of mitochondrial dysfunctions and sarcopenia. To test this hypothesis, we investigated the impact of Parkin overexpression in skeletal muscles of young and old mice. Parkin was overexpressed for 4 months in muscles of young (3 months) and late middle-aged (18 months) mice using i.m. injections of adeno-associated viruses. We show that Parkin overexpression increased muscle mass, fibre size and mitochondrial enzyme activities in both young and old muscles. In old mice, Parkin overexpression increased muscle strength, peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) and mitochondrial density. Parkin overexpression also attenuated the ageing-related increase in 4-hydroxynonenal content (a marker of oxidative stress) and type I collagen content (a marker of fibrosis), as well as the number of terminal deoxynucleotidyl transferase dUTP nick-end labelling-positive myonuclei (a marker of apoptosis). Overall, our results indicate that Parkin overexpression attenuates sarcopenia and unexpectedly causes hypertrophy in adult muscles. They also show that Parkin overexpression leads to increases in mitochondrial content and enzymatic activities. Finally, our results show that Parkin overexpression protects against oxidative stress, fibrosis and apoptosis. These findings highlight that Parkin may be an attractive therapeutic target with respect to attenuating sarcopenia and improving skeletal muscle health and performance.

Changes in Redox Signaling in the Skeletal Muscle with Aging

Reduction in muscle strength with aging is due to both loss of muscle mass (quantity) and intrinsic force production (quality). Along with decreased functional capacity of the muscle, age-related muscle loss is associated with corresponding comorbidities and healthcare costs. Mitochondrial dysfunction and increased oxidative stress are the central driving forces for age-related skeletal muscle abnormalities. The increased oxidative stress in the aged muscle can lead to altered excitation-contraction coupling and calcium homeostasis. Furthermore, apoptosis-mediated fiber loss, atrophy of the remaining fibers, dysfunction of the satellite cells (muscle stem cells), and concomitant impaired muscle regeneration are also the consequences of increased oxidative stress, leading to a decrease in muscle mass, strength, and function of the aged muscle. Here we summarize the possible effects of oxidative stress in the aged muscle and the benefits of physical activity and antioxidant therapy.

Application of current sarcopenia definitions in spinal cord injury

OBJECTIVE

Little is known about how appropriate the working definitions of sarcopenia are in subjects with spinal cord injury (SCI). This study aimed to evaluate the application of current sarcopenia definitions in SCI.

METHODS

We compared 31 complete SCI men with 33 able-bodied age matched subjects. All were examined by whole body DXA (Norland XR 36, USA) regarding muscle and fat mass and by peripheral quantitative computed tomography (pQCT XCT-3000, Germany) in 66% of tibia's length (muscle cross sectional area, (CSA) in mm²). Low muscle mass was defined by skeletal muscle index, (SMI= appendicular lean mass (aLM)/height² in Kg/m²) and by the residual method: relative aLM, 20^th percentile of the distribution of residuals as the cutoff point, (RASM), respectively. CSA is a surrogate for force.

RESULTS

We found lower values on RASM (p<0.001), and SMI (p<0.001) compared to controls in SCI and difference in the rate of sarcopenia according to sarcopenia definitions. CSA was significantly decreased in SCI (p<0.001) and correlation with duration of paralysis was weak.

CONCLUSION

Current functional definitions of sarcopenia classify different individuals as sarcopenic. Sarcopenia was more prevalent in SCI. The sensitivity and specificity of using these measurements in SCI remain unclear.

Effect of loop diuretics on skeletal muscle depletion in patients with liver cirrhosis

AIM

Sarcopenia, the loss of skeletal muscle mass, impairs prognosis of patients with liver cirrhosis. The aim of this study was to investigate the effect of loop diuretics, which are frequently used to treat hepatic edema/ascites, on skeletal muscle depletion and the prognosis in patients with liver cirrhosis.

METHODS

This retrospective study evaluated 226 patients with liver cirrhosis. The skeletal muscle cross-sectional area at the level of the third lumbar vertebra was measured using computed tomography. The relative change in skeletal muscle area per year (ΔSMA) was calculated, and the association between ΔSMA and therapeutic dosage of loop diuretics was examined.

RESULTS

The therapeutic dosage of loop diuretics was inversely correlated with ΔSMA by simple (r = -0.27, P < 0.0001) and multiple regression analyses (t = -3.07, P = 0.002). During a median follow-up period of 49 months, 82 patients died. Overall survival rates were lower in patients treated with loop diuretics at >20 mg than in those who received ≤20 mg (median, 66 vs. 97 months; P = 0.002). Multivariate analysis revealed that loop diuretics of >20 mg (hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.03-3.24; P = 0.039) and ΔSMA of ≤-3.1% (HR, 3.87; 95% CI, 2.32-6.60; P < 0.0001) were independently associated with mortality.

CONCLUSIONS

A higher dose of loop diuretic use was associated with more rapid skeletal muscle depletion and poor survival in patients with liver cirrhosis, independent of the severity of liver disease.

5-Hydroxy-7-methoxyflavone derivatives from Kaempferia parviflora induce skeletal muscle hypertrophy

Skeletal muscle plays a critical role in locomotion and energy metabolism. Maintenance or enhancement of skeletal muscle mass contributes to the improvement of mobility and prevents the development of metabolic diseases. The extracts from Kaempferia parviflora rhizomes contain at least ten methoxyflavone derivatives that exhibit enhancing effects on ATP production and glucose uptake in skeletal muscle cells. In the present study, we investigated the effects of ten K. parviflora-derived methoxyflavone derivatives (six 5,7-dimethoxyflavone (DMF) derivatives and four 5-hydroxy-7-methoxyflavone (HMF) derivatives) on skeletal muscle hypertrophy. Murine C2C12 myotubes and senescence-accelerated mouse-prone 1 (SAMP1) mice treated with methoxyflavones were used as experimental models to determine the effects of HMF derivatives on myotube diameter and size and muscle mass. The four HMF derivatives, but not the six DMF derivatives, increased myotube diameter. The 5-hydroxyflavone, 7-methoxyflavone, and 5,7-dihydroxyflavone had no influence on myotube size, a result that differed from HMF. Dietary administration of the mixture composed of the four HMF derivatives resulted in increase in the soleus muscle size and mass in SAMP1 mice. HMF derivatives also promoted protein synthesis in myotubes, and treatment with the intracellular Ca2+ chelator BAPTA-AM, which depletes intracellular Ca2+ levels, inhibited this promotion. Furthermore, BAPTA-AM inhibited HMF-promoted protein synthesis even when myotubes were incubated in Ca2+-free medium. These results indicate that HMF derivatives induce myotube hypertrophy and that both the 5-hydroxyl group and the 7-methoxy group in the flavones are necessary for myotube hypertrophy. Furthermore, these results suggest that HMF-induced protein synthesis requires intracellular Ca2+, but not extracellular Ca2+.

Association of hyperuricemia with disease severity in chronic hepatitis C patients

BACKGROUND/AIMS

Hepatitis C virus (HCV) infection is associated with extrahepatic manifestations such as metabolic abnormalities. The association between chronic hepatitis C (CHC) and uric acid levels has rarely been investigated. We aimed to evaluate the levels of serum uric acid in CHC patients.

METHODS

Three hundred and seventy-three histologically confirmed CHC patients who were scheduled to receive antiviral therapy were consecutively enrolled, and 746 age- and sex-matched uninfected controls were included for comparison. Hyperuricemia was defined as a uric acid level > 7 mg/dL in men and > 6.0 mg/dL in women.

RESULTS

Hyperuricemia was identified in 15.8% of the CHC patients. The uric acid levels did not differ between the CHC patients and the controls (5.54 ± 1.20 mg/dL vs. 5.45 ± 1.45 mg/dL, P = 0.3). Among the 373 CHC patients, the factors associated with hyperuricemia included body mass index (BMI) (OR/CI: 1.13/1.04-1.21, P = 0.003) and estimated glomerular filtration rate (eGFR) (OR/CI: 0.98/0.97-1.00, P = 0.02). Logistic regression analysis revealed that the factors associated with hyperuricemia in male patients included BMI (OR/CI: 1.12/1.05-1.30, P = 0.006) and advanced fibrosis (F3-4) (OR/CI: 0.27/0.09-0.83, P = 0.02), whereas the factors associated with hyperuricemia in female patients included eGFR (OR/CI: 0.97/0.95-0.99, P = 0.02) and diabetes (OR/CI: 3.03/1.11-8.25, P = 0.03). There was a significant decreasing trend of serum uric acid levels with the progression of fibrotic stages among male patients (6.21 ± 1.03 mg/dL 5.82 ± 1.16 mg/dL and 5.44 ± 1.28 mg/dL in stages F0-2, F3, and F4, respectively, trend P = 0.01).

CONCLUSIONS

Hyperuricemia was inversely associated with liver disease severity in CHC male patients.

Nutritional support in chronic liver disease and cirrhotics

The liver is a major organ and an essential component in maintaining an appropriate nutritional status in healthy individuals through metabolism of protein, carbohydrates, and fat. In individuals with chronic liver disease (CLD), along with a number of other essential functions that the liver serves, its role in nutrition maintenance is severely impaired. Common causes of CLD include hepatitis C, alcoholic liver disease, and non-alcoholic liver disease. Amongst this population, the most common manifestation of impaired nutritional maintenance is protein-calorie malnutrition. Aside from inherent abnormalities in metabolism, such as malabsorption and maldigestion, CLD can be associated with anorexia as well as increased metabolic requirements, all of which contribute to a state of malnutrition. Given the systemic implications and impact on prognosis of malnutrition, proper nutritional assessment is essential and can be achieved through a thorough history and physical, as well as biochemical investigations and anthropometry as needed. Following an appropriate assessment of a patient’s nutritional status, an approach to management can be decided upon and is based on the extent of malnutrition which directly reflects the severity of disease. Management options can be grossly separated into enteral and parenteral nutrition. The former is usually sufficient in the form of oral supplements in less severe cases of malnutrition, but as the CLD worsens, parenteral nutrition becomes necessary. With appropriate assessment and early intervention, many of the complications of CLD can be avoided, and ultimately better outcomes can be achieved.

Dietary Protein Sources and Muscle Mass over the Life Course: The Lifelines Cohort Study

The influence of dietary protein intake on muscle mass in adults remains unclear. Our objective was to investigate the association between protein intake and muscle mass in 31,278 men and 45,355 women from the Lifelines Cohort. Protein intake was estimated by food frequency questionnaire and muscle mass was estimated from 24 h urinary creatinine excretion. The age range was 18⁻91 years and mean total protein intake was 1.0 ± 0.3 g/kg/day. Across increasing quartiles of total protein intake, animal protein intake, and fish/meat/egg protein intake, creatinine excretion significantly increased in both men (+4% for total and +6% for fish/meat/egg protein intake, p < 0.001) and women (+3% for total and +6% for fish/meat/egg protein intake, p < 0.001). The associations were not systematically stronger or weaker with increasing age, but associations were strongest for young men (26⁻45 years) and older women (>75 years). The association between total protein intake and muscle mass was dependent on physical activity in women (p interaction < 0.001). This study suggests that total protein intake, animal protein intake, and in particular fish/meat/egg protein intake may be important for building and preserving muscle mass. Dietary protein sources should be further studied for their potential to build and preserve muscle mass.

Impact of Sarcopenia as a Prognostic Biomarker of Bladder Cancer

Sarcopenia, the degenerative and systemic loss of skeletal muscle mass, indicates patient frailty and impaired physical function. Sarcopenia can be caused by multiple factors, including advanced age, lack of exercise, poor nutritional status, inflammatory diseases, endocrine diseases, and malignancies. In patients with cancer cachexia, anorexia, poor nutrition and systemic inflammation make the metabolic state more catabolic, resulting in sarcopenia. Thus, sarcopenia is considered as one of manifestations of cancer cachexia. Recently, growing evidence has indicated the importance of sarcopenia in the management of patients with various cancers. Sarcopenia is associated with not only higher rates of treatment-related complications but also worse prognosis in cancer-bearing patients. In this article, we summarized metabolic backgrounds of cancer cachexia and sarcopenia and definitions of sarcopenia based on computed tomography (CT) images. We conducted a systematic literature review regarding the significance of sarcopenia as a prognostic biomarker of bladder cancer. We also reviewed recent studies focusing on the prognostic role of changes in skeletal muscle mass during the course of treatment in bladder cancer patients. Lastly, we discussed the impact of nutritional support, medication, and exercise on sarcopenia in cancer-bearing patients.

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.

Whey protein supplementation for the preservation of mass and muscular strength of patients with heart failure: study protocol for a randomized controlled trial

Background

Heart failure (HF) is an important public health problem, considered a new epidemic with high morbidity and mortality. The progression of HF often determines weight reduction, muscle mass loss, and reduced physical ability. Whey protein supplementation may increase the effects of exercise on strength and muscle mass, in addition to promoting improved endothelial function, body composition and quality of life. However, studies are needed to evaluate its benefits in patients with HF.

Methods/design

This is a double-blind, randomized, placebo-controlled clinical trial in which patients with HF will be randomly allocated to two groups to receive supplementation with whey protein or placebo, associated with supervised exercise, for 12 weeks. The frequency of exercise will be three times a week. The study variables will be evaluated at baseline and 12 weeks. The main outcome will be maintenance of muscle mass and strength. Microvascular reactivity, quality of life, and inflammatory parameters will be evaluated as secondary outcomes.

Discussion

HF is associated with severe loss of muscle mass and strength, directly contributing to exercise intolerance and inability to maintain daily life activities, becoming a strong predictor of reduced quality of life and mortality. The results of this study will add to the evidence base for providing new dietary recommendations.

Trial registration

ClinicalTrials.gov, ID: NCT03142399. Registered on 29 May 2016. Effect of Whey Protein’ Supplementation and Exercise in Patients with Heart Failure (PROT-HF).

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2811-4) contains supplementary material, which is available to authorized users.

Heritability of muscle mass in Korean parent-offspring pairs in the Fifth Korean National Health and Nutrition Examination Survey (KNHANES V)

OBJECTIVES

Decreased muscle mass is known to be associated with several serious medical conditions. We analyzed the Fifth Korean National Health and Nutrition Examination Survey (KNHANES V, 2010-2011) to estimate the heritability of muscle mass in Korean parent-offspring pairs.

STUDY DESIGN

Cross-sectional.

MAIN OUTCOME MEASURES

A total of 1233 parents (average age 57.67 ± 8.50 years) and 917 offspring (average age 29.10 ± 7.57 years) from 743 families were included in the analysis. Muscle mass was estimated based on three different indices: appendicular skeletal muscle mass (ASM) measured with a dual-energy X-ray absorptiometry (DXA), weight-adjusted ASM (SMI), and height-adjusted ASM (RASM). The heritability was estimated by employing the maximum-likelihood variance components implemented in Sequential Oligogenic Linkage Analysis Routines (SOLAR). The best-fitting model was determined out of four polygenic models. Pearson's partial correlation coefficient was also calculated using the muscle mass indices to further study the association between father or mother and son or daughter pairs.

RESULTS

The heritability estimates of the muscle mass indices ranged from 55% to 80% (all p < 0.01). The correlation coefficient of father and offspring ranged from 0.11 to 0.40, while that of mother and offspring ranged from 0.23 to 0.43 (all p < 0.01).

CONCLUSIONS

The heritability estimates of muscle mass in Koreans are large and significant, suggesting that parental muscle mass is an important predictor of the offspring's muscle mass. The result implies that there may be a genetic factor partly determining muscle mass.

Fabrication of Micromolded Gelatin Hydrogels for Long-Term Culture of Aligned Skeletal Myotubes

Cultured skeletal myotubes are a powerful in vitro system for identifying mechanisms of skeletal muscle development and disease. However, skeletal myotubes routinely delaminate from conventional culture substrates after approximately 1 week, which significantly hampers their utility for in vitro disease modeling and drug screening. To address this problem, we fabricated micromolded gelatin hydrogels as culture substrates that are more biomimetic than conventional substrates. On micromolded gelatin hydrogels, C2C12 skeletal myoblasts align and differentiate into skeletal myotubes that are stable in culture for multiple weeks. With this protocol, we detail three key steps: (1) Fabrication of micromolded gelatin hydrogels; (2) Culture of mouse C2C12 myoblasts and differentiation into myotubes; and (3) Quantification of myotube morphology. These substrates have many applications for skeletal muscle disease modeling and drug screening over longer time scales.

Sarcopenia: assessment of disease burden and strategies to improve outcomes

Life expectancy is increasing worldwide, with a resultant increase in the elderly population. Aging is characterized by the progressive loss of skeletal muscle mass and strength - a phenomenon called sarcopenia. Sarcopenia has a complex multifactorial pathogenesis, which involves not only age-related changes in neuromuscular function, muscle protein turnover, and hormone levels and sensitivity, but also a chronic pro-inflammatory state, oxidative stress, and behavioral factors - in particular, nutritional status and degree of physical activity. According to the operational definition by the European Working Group on Sarcopenia in Older People (EWGSOP), the diagnosis of sarcopenia requires the presence of both low muscle mass and low muscle function, which can be defined by low muscle strength or low physical performance. Moreover, biomarkers of sarcopenia have been identified for its early detection and for a detailed identification of the main pathophysiological mechanisms involved in its development. Because sarcopenia is associated with important adverse health outcomes, such as frailty, hospitalization, and mortality, several therapeutic strategies have been identified that involve exercise training, nutritional supplementation, hormonal therapies, and novel strategies and are still under investigation. At the present time, only physical exercise has showed a positive effect in managing and preventing sarcopenia and its adverse health outcomes. Thus, further well-designed and well-conducted studies on sarcopenia are needed.

Effects of Low Muscle Mass on Albuminuria and Chronic Kidney Disease in Patients With Type 2 Diabetes: The Korean Sarcopenic Obesity Study (KSOS)

Background

Previous studies have shown that chronic kidney disease (CKD) is associated with accelerated loss of skeletal muscle in patients on dialysis. However, the relationships of sarcopenia with albuminuria and early-stage CKD in patients with type 2 diabetes have not been examined.

Methods

We analyzed diabetic subgroup data from 409 patients with type 2 diabetes from the Korean Sarcopenic Obesity Study (KSOS). Sarcopenia was defined as a skeletal muscle mass index (SMI; SMI [%] = total skeletal muscle mass [kg]/weight [kg] × 100) less than 2 SD below the sex-specific mean for a younger reference group. The estimated glomerular filtration rates and urinary albumin-to-creatinine ratios were used to assess renal function and albuminuria.

Results

The prevalence of sarcopenia was significantly increased in the albuminuria group compared with the normo-albuminuria group (26.7% vs 12.6%, p = .001), as well as in CKD 3 group compared with the CKD 1-2 group (46.7% vs 15.1%, p = .005). After adjusting for age, SMI was negatively correlated with urinary albumin-to-creatinine ratios and positively correlated with aspartate aminotransferase, alanine aminotransferase, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels. Multiple logistic regression analysis revealed that the odds ratio for albuminuria association was 3.02 (95% CI 1.37-6.67) in the lowest tertile of SMI compared with the highest tertile after adjusting for various confounding factors.

Conclusions

Sarcopenia is more prevalent in individuals with albuminuria than in those without albuminuria. Furthermore, increased albuminuria is independently associated with low muscle mass in patients with type 2 diabetes.

Pathophysiological analyses of skeletal muscle in obese type 2 diabetes SDT fatty rats

Sarcopenia is the age-related decrease of muscle mass and function. Diabetes and obesity are known to be risk factors that exacerbate sarcopenia, but the underlying mechanism of diabetes-related sarcopenia is still unknown. Obese type 2 diabetes SDT fatty rats show early onset of severe diabetes and there have been no reports on the characteristics of their skeletal muscle. Therefore, pathophysiological analyses were performed for the skeletal muscle in these rats. Diabetic male SDT fatty rats were sacrificed at 8, 16, 24, 32 and 40 weeks of age. Age-matched Sprague Dawley (SD) rats were used as the normal control. In addition to biological blood parameters, the soleus and the extensor digitorum longus muscles were examined for muscle weight, histopathology, and protein synthesis and degradation. Muscle grip strength was also examined. These results revealed that the muscle weights of the SDT fatty rats were significantly decreased from 16 weeks of age. The mean cross-sectional area of muscle fibers in the SDT fatty rats decreased from 24 weeks of age. Increased intramyocellular lipid accumulation, identified by immunohistochemistry for adipophilin and TEM, was observed in the SDT fatty rats from 8 weeks of age. Plasma insulin-like growth factor (IGF)-1 levels and muscle strength in the SDT fatty rats decreased at 24 weeks of age and thereafter. These pathophysiological findings have been reported both in sarcopenia in aged humans and in patients with diabetes. In conclusion, the SDT fatty rat was considered to be a useful model for analysis of diabetes-related sarcopenia.

Nutritional management of older adults with gastrointestinal cancers: An International Society of Geriatric Oncology (SIOG) review paper

Malnutrition is one of the most common physical manifestations of gastrointestinal (GI) cancers and is often under-diagnosed and under-treated. Like cancers, malnutrition occurs more commonly in older adults, with potential negative consequences to quality of life, functional status, tolerance to treatment, and prognosis. Nutritional assessment and management require a proactive and systematic, multi-disciplinary approach. Early assessment, detection, and prompt intervention of cancer-associated malnutrition and cachexia are equally essential to achieve better quality nutritional care for older oncology patients. This article aims to provide an overview of the evidence associated with poor nutrition and outcomes in older adults with GI cancers, and recommends a management approach from a geriatric oncologist's perspective.

Sarcopenia: a chronic complication of type 2 diabetes mellitus

BACKGROUND

Diabetics are at increased risk for impaired mobility and strength, frequently related to the disease control. Sarcopenia is the reduction of muscle mass associated with the decrease in muscle strength and/or performance, resulting in worse morbidity in chronic diseases.

METHODS

The objectives of this paper was to assess the prevalence of sarcopenia in patients with type 2 diabetes mellitus (T2DM) and determine its association with diabetes characteristics, progression, and complications, as well as changes in bone mineral density. The sample consisted of patients with T2DM followed at the outpatient clinics of the Serviço de Endocrinologia e Metabologia do Hospital de Clínicas da Universidade Federal do Paraná, from March to August 2016. Participants were men and women above 18 years with T2DM diagnosed at least 1 year earlier. Individuals with chronic diseases, users of any drug that modifies body composition, patients with body mass index (BMI) > 35 or < 18 kg/m², and users of illicit drugs or hormonal or nutritional supplementation were excluded. The selected patients answered questionnaires about demographics, eating habits, and disease characteristics, and performed a bone densitometry exam in a dual energy absorptiometry (total body; spine and femur (total and neck)), a handgrip test by manual dynamometer, and an evaluation of the abdominal circumference (AC). The medical records were reviewed seeking diabetes data and laboratory test results. Patients were matched for sex, age, and race with healthy controls [Control Group (CG)]. The diagnosis of sarcopenia was conducted according to the criteria of the Foundation for National Institute of Health.

RESULTS

The final sample consisted of 83 patients in the DG and 83 in the CG. The DG had higher BMI, WC, past history of fractures and lower calcium and healthy diet intake (p < 0.005), compared to the CG. The DG presented a higher frequency of abnormal BMD (osteopenia in 45 (53%), and osteoporosis in 14 (19%)) and comorbidities than the CG (p < 0.005). Pre-sarcopenia was not different between groups, but muscle weakness was present in 25 diabetics (18 women) and only in 5 controls (4 men) (p = 0.00036). Sarcopenia was diagnosed in 13 (16.2%) patients in the DG and 2 (2.4%) in the CG (p = 0.01168). Pre-sarcopenia and sarcopenia were associated with altered BMD (p < 0.005), with no association with diabetes duration or control. Body mass index and osteoporosis increased the likelihood to have sarcopenia, but hypertension and healthy diet decreased it.

CONCLUSION

The DG had altered BMD associated with worse glycemic control, and a higher prevalence of sarcopenia, suggesting the need to look for their presence in diabetics.

Depression and Handgrip Strength Among U.S. Adults Aged 60 Years and Older from NHANES 2011-2014

OBJECTIVES

Sarcopenia is a gradual loss of muscle mass and strength that occurs with aging. This muscle deterioration is linked to increased morbidity, disability, and other adverse outcomes. Although reduced handgrip strength can be considered a marker of sarcopenia and other aging-related decline in the elderly, there is limited research on this physical health problem in at-risk groups with common biopsychosocial conditions such as depression. Our primary objective was to ascertain level of combined handgrip strength and its relationship with depression among adults aged 60 years and older.

DESIGN

Unadjusted and adjusted linear regression models were conducted with a cross-sectional survey dataset.

SETTING

Secondary dataset from the 2011-2014 National Health and Nutrition Examination Survey (NHANES).

PARTICIPANTS

Community-dwelling, non-institutionalized adults ≥60 years old (n=3,421).

MEASUREMENTS

The predictor variables included a positive screen for clinically relevant depression (referent=PHQ-9 score <10). The criterion variable of combined handgrip strength (kg) was determined using a dynamometer.

RESULTS

Mean age and BMI were 69.9 years (51.5% female) and 28.8 kg/m2, respectively. Mean combined handgrip strength in the overall cohort was 73.5 and 46.6 kg in males and females, respectively. Three hundred thirty-six (9.8%) reported symptoms of depression. In unadjusted and fully adjusted models, depression was significantly associated with reduced handgrip strength (B = -0.26±0.79 and B = -0.19±0.08, respectively; p<0.001).

CONCLUSION

Our findings demonstrate handgrip strength has a significant inverse association with depression. Future longitudinal studies should investigate the causal processes and potential moderators and mediators of the relationships between depression and reduced handgrip strength. This information may further encourage the use of depression and handgrip strength assessments and aid in the monitoring and implementation of health care services that address both physical and mental health limitations among older adult populations.