Endothelial function and the regulation of muscle protein anabolism in older adults

Causal Associations with Arterial Stiffness and Sarcopenia: A Mendelian Randomization Analysis

Observational studies and clinical trials indicate a link between arterial stiffness (AS) and sarcopenia (SAR), yet the causal relationship between these remains unclear. The study aims to investigate the causal connection from AS to SAR by Mendelian randomization (MR). We analyzed Genome-Wide Association Studies data for AS indicators: pulse wave arterial stiffness index (PWASI) and pulse wave peak-to-peak time (PPT), and SAR indicators: low hand grip strength (LHGS), usual walking pace (UWP), moderate-to-vigorous physical activity levels (MVPA), and walk or cycle unassisted for 10 minutes. The inverse variance-weighted, MR-Egger, weighted mode, and weighted median were applied to MR. There is a bidirectional causal relationship between the AS and SAR. The PWASI has a causation with UWP (odds ratio [OR] = 0.97, 95% confidence interval [CI] = 0.94-0.99). The PPT has a causal association with MVPA (OR = 1.08, 95% CI = 1.002-1.144) and UWP (OR = 1.05, 95% CI = 1.017-1.096). The LHGS is causally associated with PPT (OR = 0.95, 95% CI = 0.91-0.98) and UWP has a causal association with PWASI (OR = 0.77, 95% CI = 0.65-0.90) and PPT (OR = 1.37, 95% CI = 1.17-1.60). The increased AS could reduce the motor ability slightly and the lower upper and lower limb strength could lead to the higher AS. This bidirectional causal relationship of the two may offer novel perspectives for advancing the understanding of the underlying mechanisms related to AS and muscle pathophysiology.

Association of kidney function with physical performance: the Maastricht study

BACKGROUND

Kidney failure has been associated with decreased physical capacity, although evidence regarding the physical performance of individuals with earlier stages of chronic kidney disease (CKD) remains limited.

METHODS

Cross-sectional data were derived from the prospective, population-based Maastricht Study. Multivariate linear regression models were fitted to assess the association of estimated glomerular filtration rate (eGFR) and albuminuria categories with physical performance test outcomes.

RESULTS

Overall, 7396 participants were included. Compared to eGFR 60-90 ml/min/1.73 m2, values < 60 ml/min/1.73 m2 were associated with significantly shorter 6-min walk distance (β: - 13.04 m, 95% confidence intervals-CI - 19.95; - 6.13), worse timed chair rise stand test time (β: 0.91 s, 95% CI 0.36; 1.47), lower maximal grip (β: - 0.83 kg, 95% CI - 1.50; - 0.15) and elbow flexion (β: - 3.64 Nm, 95% CI - 7.11; - 0.16) strength. Additionally, eGFR > 90 ml/min/1.73 m2 was linked to significantly shorter 6-min walk distance (β: - 6.13 m, 95% CI - 9.44; - 2.82). Urinary albumin excretion > 30 mg/24 h was associated with shorter 6-min walk distance (β: - 12.48 m, 95% CI - 18.28; - 6.68), worse timed chair rise stand test time (β: 0.51 s, 95% CI 0.11; 1.06), lower maximal grip (β: - 1.34 kg, 95% CI - 1.91; - 0.76) and elbow flexion strength (β: - 3.31 Nm, 95% CI - 5.80; - 0.82).

CONCLUSIONS

Reduced eGFR and higher albuminuria levels were associated with worse physical performance, especially shorter 6-min walk distance and lower muscle strength. The relationship between eGFR and physical function was non-linear, with also high eGFR values being associated with worse performance, especially in the six-minute walk test.

Sarcopenia is independently associated with poor preoperative physical fitness in patients undergoing colorectal cancer surgery

BACKGROUND

Accurate preoperative risk assessment for major colorectal cancer (CRC) surgery remains challenging. Body composition (BC) and cardiopulmonary exercise testing (CPET) can be used to evaluate risk. The relationship between BC and CPET in patients undergoing curative CRC surgery is unclear.

METHODS

Consecutive patients undergoing CPET prior to CRC surgery between 2010 and 2020 were identified between two different UK hospitals. Body composition phenotypes such as sarcopenia, myosteatosis, and visceral obesity were defined using widely accepted thresholds using preoperative single axial slice CT image at L3 vertebrae. Relationships between clinicopathological, BC, and CPET variables were investigated using linear regression analysis.

RESULTS

Two hundred eighteen patients with stage I-III CRC were included. The prevalence of sarcopenia, myosteatosis, and visceral obesity was 62%, 33%, and 64%, respectively. The median oxygen uptake at anaerobic threshold (VO2 at AT) was 12.2 mL/kg/min (IQR 10.6-14.2), and oxygen uptake at peak exercise (VO2 peak) was 18.8 mL/kg/min (IQR 15.4-23). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 at AT. While ASA grade (P < 0.001) and BMI (P = 0.007) were negatively associated with VO2 at AT, on multivariate linear regression analysis, these variables remained significant (P < 0.05). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 peak, whereas age (P < 0.001), ASA grade (P < 0.001), BMI (P = 0.003), sarcopenia (P = 0.015), and myosteatosis (P < 0.001) were negatively associated with VO2 peak. On multivariate linear regression analysis age (P < 0.001), ASA grade (P < 0.001), BMI (P < 0.001), and sarcopenia (P = 0.006) were independently and negatively associated with VO2 peak.

CONCLUSIONS

The novel finding that sarcopenia is independently associated with reduced VO2 peak performance in CPET supports the supposition that reduced muscle mass relates to poor physical function in CRC patients. Further work should be undertaken to assess whether sarcopenia diagnosed on CT can act as suitable surrogate for CPET to further enhance personalized risk stratification.

Sarcopenic obesity in older adults: a clinical overview

Sarcopenic obesity is characterized by a concurrent decline in muscle mass and function, along with increased adipose tissue. Sarcopenic obesity is a growing concern in older adults owing to significant health consequences, including implications for mortality, comorbidities and risk of developing geriatric syndromes. A 2022 consensus statement established a new definition and diagnostic criteria for sarcopenic obesity. The pathophysiology of this condition involves a complex interplay between muscle, adipose tissue, hormonal changes, inflammation, oxidative stress and lifestyle factors, among others. Sarcopenic obesity is treated with a range of management approaches, such as lifestyle interventions, exercise, nutrition and medical therapies. Emerging therapies that were developed for treating other conditions may be relevant to sarcopenic obesity, including novel pharmacological agents and personalized approaches such as precision medicine. In this Review, we synthesize the current knowledge of the clinical importance of sarcopenic obesity, its assessment and diagnosis, along with current and emerging management strategies.

The Relationship Between Sarcopenia And Proteinuria, What Do We Know?

Sarcopenia is one of the most common geriatric syndromes in the elderly. It is defined as a decrease in muscle mass and function, and it can lead to physical disability, falls, poor quality of life, impaired immune system, and death. It is known that, the frequency of sarcopenia increases in the kidney patient population compared to healthy individuals. Although it is known that kidney disease can lead to sarcopenia; our knowledge of whether sarcopenia causes kidney disease is limited. Prior studies have suggested that protein energy wasting may be a risk of de novo CKD. Proteinuria is an important manifestation of kidney disease and there is a relationship between sarcopenia and proteinuria in diabetes, geriatric population, kidney transplant, and nephrotic syndrome. Does proteinuria cause sarcopenia or vice versa? Are they both the results of common mechanisms? This issue is not clearly known. In this review, we examined the relationship between sarcopenia and proteinuria in the light of other studies.

Sarcopenia and Cardiovascular Diseases

Sarcopenia is the loss of muscle strength, mass, and function, which is often exacerbated by chronic comorbidities including cardiovascular diseases, chronic kidney disease, and cancer. Sarcopenia is associated with faster progression of cardiovascular diseases and higher risk of mortality, falls, and reduced quality of life, particularly among older adults. Although the pathophysiologic mechanisms are complex, the broad underlying cause of sarcopenia includes an imbalance between anabolic and catabolic muscle homeostasis with or without neuronal degeneration. The intrinsic molecular mechanisms of aging, chronic illness, malnutrition, and immobility are associated with the development of sarcopenia. Screening and testing for sarcopenia may be particularly important among those with chronic disease states. Early recognition of sarcopenia is important because it can provide an opportunity for interventions to reverse or delay the progression of muscle disorder, which may ultimately impact cardiovascular outcomes. Relying on body mass index is not useful for screening because many patients will have sarcopenic obesity, a particularly important phenotype among older cardiac patients. In this review, we aimed to: (1) provide a definition of sarcopenia within the context of muscle wasting disorders; (2) summarize the associations between sarcopenia and different cardiovascular diseases; (3) highlight an approach for a diagnostic evaluation; (4) discuss management strategies for sarcopenia; and (5) outline key gaps in knowledge with implications for the future of the field.

Sarcopenia and cardiovascular disease in patients with and without kidney disease: what do we know?

Cardiovascular disease (CVD) incidence is high in patients with chronic kidney disease (CKD) and is the most frequent cause of mortality in this population. Advanced age, hypertension, uremic toxins, endothelial dysfunction, atherosclerosis, hyperhomocysteinemia, oxidative stress, and inflammation are among the leading causes of increased CVD in advanced stages of CKD. Although defined as a decrease in muscle strength associated with aging, sarcopenia is also prevalent in CKD patients. Sarcopenia causes physical disability, low quality of life, and mortality. Regular exercise and nutritional supplementation may slow the progression of sarcopenia. Recent studies have shown that sarcopenia increases the risk of CVD and mortality in people with or without kidney disease. This review discusses the relationship between sarcopenia and CVD in light of the current literature.

Major dietary patterns in relation to muscle strength status among middle-aged people: A cross-sectional study within the RaNCD cohort

Grip strength in midlife can predict physical disability in senior years. Recent evidence shows the critical role of nutritional status on muscle function. We aimed to elucidate whether adherence to a particular dietary pattern would be associated with abnormal muscle strength among middle-aged people. In this cross-sectional study, a semiquantitative Food Frequency Questionnaire was used to assess the dietary intake of 2781 participants in the Ravansar Non-Communicable Chronic Disease (RaNCD) cohort. Major dietary patterns from 28 main food groups were extracted using principal component analysis. Binary logistic regression was used to determine the association between the tertiles of the major dietary patterns and muscle strength status. Two major dietary patterns were identified: the "mixed dietary pattern" that heavily loaded with fruits, vegetables, nuts, dairies, sweets, legumes, dried fruits, fish, red meat, butter, whole grains, natural juices, poultry, pickles, olive, industrial juice, egg, processed meat, and snacks and "unhealthy dietary pattern" that heavily loaded by fats, sugar, refined grains, soft drink, salt, organ meat, tea, and coffee. Adherence to the mixed dietary pattern (OR = 1.03, 95% CI = 0.8-1.33, P for trend = 0.77) and the unhealthy dietary pattern (OR = 1.01, 95% CI = 0.79-0.13, P for trend = 0.89) did not associate with abnormal muscle strength. This study suggests that the dietary pattern involving the consumption of healthy and unhealthy food does not have an effect on muscle strength in middle-aged adults.

Sarcopenia in the elderly versus microcirculation, inflammation status, and oxidative stress: A cross-sectional study

BACKGROUND

Age-related mechanisms of sarcopenia associated with vascular function have been recently suggested. This study compared and tested associations between muscle mass and strength, microcirculation, inflammatory biomarkers, and oxidative stress in older adults classified as sarcopenic and non-sarcopenic.

METHODS

Thirty-three physically inactive individuals (72±7 yrs) were assigned to age-matched sarcopenic (SG) and non-sarcopenic (NSG) groups. Between-group comparisons were performed for appendicular skeletal mass (ASM), handgrip and isokinetic strength, microvascular function and morphology, C-reactive protein, insulin-like growth factor-1, tumor necrosis factor-alpha, interleukin-6 (IL-6), soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1, endothelin-1, and oxidized low-density lipoprotein.

RESULTS

ASM and knee isokinetic strength were lower in SG than NSG (P <  0.05). No difference between groups was found for outcomes of microvascular function and morphology, but log-transformed IL-6 concentration was twice greater in SG vs. NSG (P = 0.02). Correlations between ASM index, handgrip and knee isokinetic strength vs. markers of microcirculatory function, capillary diameters, vascular reactivity, and endothelial injury were found only in SG.

CONCLUSION

Decreased ASM index and strength have been associated with microcirculatory profile, indicating that microcirculation impairment may be involved somehow in Sarcopenia development. The inflammation status, particularly elevated IL-6, seems to play an important role in this process.

Single-Cell Transcriptional Profiling Reveals Sex and Age Diversity of Gene Expression in Mouse Endothelial Cells

Although it is well-known that sex and age are important factors regulating endothelial cell (EC) function, the impact of sex and age on the gene expression of ECs has not been systematically analyzed at the single cell level. In this study, we performed an integrated characterization of the EC transcriptome of five major organs (e.g., fat, heart-aorta, lung, limb muscle, and kidney) isolated from male and female C57BL/6 mice at 3 and 18 months of age. A total of 590 and 252 differentially expressed genes (DEGS) were identified between females and males in the 3- and 18-month subgroups, respectively. Within the younger and older group, there were 177 vs. 178 DEGS in fat, 305 vs. 469 DEGS in heart/aorta, 22 vs. 37 DEGS in kidney, 26 vs. 439 DEGS in limb muscle, and 880 vs. 274 DEGS in lung. Interestingly, LARS2, a mitochondrial leucyl tRNA synthase, involved in the translation of mitochondrially encoded genes was differentially expressed in all organs in males compared to females in the 3-month group while S100a8 and S100a9, which are calcium binding proteins that are increased in inflammatory and autoimmune states, were upregulated in all organs in males at 18 months. Importantly, findings from RNAseq were confirmed by qPCR and Western blot. Gene enrichment analysis found genes enriched in protein targeting, catabolism, mitochondrial electron transport, IL 1- and IL 2- signaling, and Wnt signaling in males vs. angiogenesis and chemotaxis in females at 3 months. In contrast, ECs from males and females at 18-months had up-regulation in similar pathways involved in inflammation and apoptosis. Taken together, our findings suggest that gene expression is largely similar between males and females in both age groups. Compared to younger mice, however, older mice have increased expression of genes involved in inflammation in endothelial cells, which may contribute to the development of chronic, non-communicable diseases like atherosclerosis, hypertension, and Alzheimer's disease with age.

Impaired pulse pressure amplification, augmentation index, and arterial stiffness are associated with reduced limb lean mass in overweight and obese postmenopausal women

BACKGROUND

The age-related muscle mass loss has been associated with increased arterial stiffness (brachial-ankle pulse wave velocity, baPWV) and wave reflection (augmentation index, AIx). In healthy individuals, pulse pressure (PP) is lower in the aorta compared to the brachial artery (PP amplification, PPA). Postmenopausal women experience elevated aortic stiffness leading to increased AIx and aortic PP causing reduced PPA, an independent predictor of cardiovascular mortality. It is unknown whether appendicular skeletal muscle index (ASMI), arm (ArmLM) or leg lean mass (LegLM) are negatively associated with PPA. The purpose of this study was to investigate the associations between vascular function (PPA, AIx, and baPWV) and lean mass (ASMI, ArmLM, and LegLM) in postmenopausal women.

METHODS

The study was performed in 93 postmenopausal women (48-71 years; BMI: 30 ± 7 kg/m²). PPA (brachial/aortic PP), aortic AIx, and baPWV were measured. ArmLM and LegLM were measured by dual-energy X-ray absorptiometry. ASMI was calculated as (ArmLM+LegLM)/Ht². Associations between vascular and lean mass measures were analyzed by multiple linear regression.

RESULTS

PPA was associated with ASMI (β = 0.29, p = .016) and LegLM (β = 0.25, p = .028) after adjustment for age, height, systolic pressure, strength, and heart rate. AIx was associated with ASMI (β = -0.27, p = .011), ArmLM (β = -0.25, p = .023), and LegLM (β = -0.22, p = .026), while baPWV was associated with reduced ASMI (β = -0.23, p = .043) and ArmLM (β = -0.23, p = .045), but not with LegLM (β = -0.19, p = .074) after full adjustment.

CONCLUSIONS

Our findings indicate that impaired pulsatile hemodynamics (PPA and AIx) are negatively associated with ASMI and LegLM, while arterial stiffness is negatively associated with ASMI and ArmLM. Thus, vascular dysfunction may be implicated in muscle mass loss in overweight and obese postmenopausal women.

Unraveling the Links Underlying Arterial Stiffness, Bone Demineralization, and Muscle Loss

The effects of elevated arterial stiffness on cardiovascular outcomes are widely studied, whereas the relation to noncardiovascular outcomes relevant to older persons, such as the effect on bones and muscles, is less well established. Arterial stiffness, bone demineralization, and muscle loss are all age-related processes with common risk factors, however, whether these are just parallel age-related alterations or whether these processes share common pathways is not yet understood. In this review, we outline previous literature using different assessments of arterial stiffness in various populations across the world to produce a comprehensive overview. Although there are many studies showing an association between arterial stiffness and loss of bone and muscle, the majority are cross-sectional and there is limited longitudinal evidence to justify causal conclusions. We also give an in-depth review of hypotheses and possible mechanisms which may underlie these associations including hormone dysregulation, impaired glucose metabolism, and inflammation. This narrative review highlights the associations between vessels, bones, and muscles with aging, offering insights into possible shared pathways.

Physical activity and exercise: Strategies to manage frailty

Frailty, a consequence of the interaction of the aging process and certain chronic diseases, compromises functional outcomes in the elderly and substantially increases their risk for developing disabilities and other adverse outcomes. Frailty follows from the combination of several impaired physiological mechanisms affecting multiple organs and systems. And, though frailty and sarcopenia are related, they are two different conditions. Thus, strategies to preserve or improve functional status should consider systemic function in addition to muscle conditioning. Physical activity/exercise is considered one of the main strategies to counteract frailty-related physical impairment in the elderly. Exercise reduces age-related oxidative damage and chronic inflammation, increases autophagy, and improves mitochondrial function, myokine profile, insulin-like growth factor-1 (IGF-1) signaling pathway, and insulin sensitivity. Exercise interventions target resistance (strength and power), aerobic, balance, and flexibility work. Each type improves different aspects of physical functioning, though they could be combined according to need and prescribed as a multicomponent intervention. Therefore, exercise intervention programs should be prescribed based on an individual's physical functioning and adapted to the ensuing response.

L-Citrulline Supports Vascular and Muscular Benefits of Exercise Training in Older Adults

Age-associated reduction in endothelial nitric oxide (NO) synthesis contributes to the development of cardiovascular diseases and sarcopenia. L-Citrulline is a precursor of NO with the ability to improve vascular function and muscle protein synthesis. We hypothesize that vascular and muscular benefits associated with oral L-citrulline supplementation might be augmented by concomitant supplementation with exercise training in older adults.

[Correlation between sarcopenia and albuminuria in patients with type 2 diabetes]

OBJECTIVE

To investigate the correlation between sarcopenia and albuminuria in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 360 T2DM patients (including 206 male and 154 female patients) hospitalized in our hospital between January, 2015 and December, 2018 were enrolled. According to their medical history and laboratory test results, the patients were divided into albuminuria group (n=122) and non-albuminuria group (n=238). The clinical and anthropological data were collected and skeletal muscle index (SMI), appendage lean mass, muscle index, total body fat, bone mineral capacity and bone mineral density were measured using dual-energy X-ray absorptiometry. Logistic regression was used to analyze the correlation of these body composition parameters with albuminuria or chronic kidney disease (CKD) in the diabetic patients.

RESULTS

The disease course of T2DM, history of hypertension, age, systolic blood pressure, low density lipoprotein cholesterol, triglyceride, uric acid, waistline, Urinary albumin creatinine ratio, serum creatinine, and glomerular filtration rate differed significantly between the diabetic patients with albuminuria and those without albuminuria (P < 0.05). The prevalence rate of sarcopenia was significantly higher in patients with albuminuria (31.4% vs 13.1%, P < 0.01). Compared with those without albuminuria, the patients with albuminuria had significantly decreased SMI (t=-2.304, P=0.021) and body mass index (Z=- 5.534, P < 0.01) and significantly increased total body fat (Z=- 2.838, P=0.005). Multivariate logistic regression analysis showed that after adjustment for age, gender, total body fat, smoking history, drinking history, duration of diabetes, HbA1c, history of hypertension, systolic blood pressure, low density lipoprotein cholesterol, body mass index, and triglyceride, the patients with a decreased SMI had a significantly increased risk of albuminuria (P=0.011 and 0.010), but SMI was not correlated with the risk of CKD in patients with T2DM (P > 0.05).

CONCLUSIONS

Sarcopenia is probably an independent risk factor for albuminuria in patients with T2DM.

Insulin-Like Growth Factor-1 (IGF-1) and Reduced Tongue Pressure in Relation to Atherosclerosis Among Community-Dwelling Elderly Japanese Men: A Cross-Sectional Study

Even though higher serum insulin-like growth factor-1 (IGF-1) levels have a positive effect on preventing reduction in muscle strength, a U-shaped association between IGF-1 and mortality has been reported. Since a recent experimental study revealed that IGF-1 is associated with atherosclerotic lesion formation, the inflammatory status of atherosclerosis could act as a confounding factor on the association between IGF-1 levels and reduced muscle strength. This study aimed to clarify the atherosclerosis-specific association between IGF-1 levels and reduced muscle strength. We conducted a cross-sectional study of 410 elderly men aged 60-89 years. Since a reduction in maximum voluntary tongue pressure against the palate (MTP) is reportedly associated with sarcopenia, we evaluated muscle strength by using MTP and defined reduced MTP as the lowest tertiles of the study population. Among study population, 295 showed no atherosclerosis (carotid intima-media thickness < 1.1 mm). Even though a significant inverse association between IGF-1 and reduced MTP was observed for subjects without atherosclerosis, no such association was detected for subjects with atherosclerosis. The known cardiovascular risk-factor adjusted odds ratio (OR) of a one-standard deviation (SD) increment (28.1 ng/mL) of IGF-1 for reduced MTP was 0.69 (0.51, 0.95) for subjects without atherosclerosis and 1.93 (1.05, 3.52) for subjects with atherosclerosis. IGF-1 was found to be inversely associated with a reduced MTP among elderly men without atherosclerosis but not among those with atherosclerosis. Atherosclerosis can thus act as a powerful confounding factor on the association between IGF-1 levels and a reduced MTP.

Metabolic and Nutritional Characteristics in Middle-Aged and Elderly Sarcopenia Patients with Type 2 Diabetes

Sarcopenia is considered to be a new complication of type 2 diabetes (T2DM) leading to increased risk of adverse outcome. We performed a survey to evaluate glucose metabolism and nutritional status in sarcopenia patients with T2DM. Diabetic participants aged ≥50 years were grouped into a probable sarcopenia group with low muscle strength (n = 405) and a nonsarcopenia group with normal muscle strength (n = 720) according to the revised recommendations from EWGSOP2 (2018). Compared to the controls, the probable sarcopenia participants were older and had lower waist-to-hip ratio and BMI, longer diabetes duration, higher fasting plasma glucose level and glycosylated hemoglobin (HbA1c), decreased estimated glomerular filtration rate and lower bone mineral content, lower fatless upper arm circumference, lower appendicular skeletal muscle mass index (ASMI), and muscle quality in both genders. Multivariable logistic regression analysis showed increased age, male, low BMI, and increased HbA1c, combined with diabetic nephropathy and decreased serum albumin levels, were risk factors associated with low muscle strength in diabetes patients. In conclusion, diabetic patients with sarcopenia had worse glucose metabolism and nutritional status, decreased renal function and reduced muscle quality ,and muscle mass with a greater likelihood of osteoporosis, who need an overall health management to improve outcomes. This clinical trial registration is registered with the Chinese Clinical Trial Registry, ChiCTR-EOC-15006901.

Targeted Metabolomics Shows Low Plasma Lysophosphatidylcholine 18:2 Predicts Greater Decline of Gait Speed in Older Adults: The Baltimore Longitudinal Study of Aging

Background

Gait speed is an important measure of lower extremity physical performance in older adults and is predictive of disability and mortality. The biological pathways involved in the decline of lower extremity physical performance are not well understood. We used a targeted metabolomics approach to identify plasma metabolites predictive of change in gait speed over time.

Methods

Gait speed was measured at baseline and over median follow-up of 50.5 months in 504 adults, aged ≥50 years, who had two or more study visits in the Baltimore Longitudinal Study of Aging (BLSA). Plasma metabolites were measured using targeted mass spectrometry (AbsoluteIDQ p180 Kit, Biocrates).

Results

Of 148 plasma metabolites (amino acids, biogenic amines, hexoses, glycerophospholipids) measured, eight were significantly associated with gait speed at baseline, independent of age and sex: hexoses (r = -0.148, p < .001), [sphingomyelin (SM) 16:1 (r = -0.091, p = .0009), SM 18:0 (r = -0.085, p = .002), SM 18:1 (r = -0.128, p < .0001], phosphatidylcholine aa 32:3 (r = -0.088, p = .001), lysophosphatidylcholine (LPC) 17:0 (r = 0.083, p = .003), LPC 18:1 (r = 0.089, p = .001), and LPC 18:2 (r = 0.104, p < .0001). Adjusting for baseline age, sex, and chronic diseases, baseline plasma LPC 18:2 was an independent predictor of the rate of change of gait speed over subsequent follow-up (p = .003). No other plasma metabolites were significantly associated longitudinal changes of gait speed over time.

Conclusions

Low plasma LPC 18:2, which has previously been shown to predict impaired glucose tolerance, insulin resistance, type 2 diabetes, coronary artery disease, and memory impairment, is an independent predictor of decline in gait speed in older adults.

PREDICTORS OF WEIGHT LOSS IN PATIENTS WITH CHRONIC HEART FAILURE AND REDUSED LEFT VENTRICULAR EJECTION FRACTION

Chronic heart failure (CHF) is a heterogeneous syndrome with a poor prognosis. Aim of the work – to define predictors of body weight (BW) loss in patients with CHF and a reduced left ventricular ejection fraction (LVEF). Materials and methods. 120 patients with stable CHF and LVEF ≤35 %, II-IV NYHA class were examined. Patients were divided into two groups according to the value of BW loss for 6 months: the first group - loss of BW <6 %, the second - ≥ 6 %. Results. Out of the 120 patients who were studied, a BW loss of ≥ 6 % occurred in 59 (49.2 %) patients. According to the results of binary logistic regression, predictors of BW loss of ≥6 % in patients with CHF and LVEF ≤ 35 % were: age, coronary heart disease, anaemia, and the number of hospitalizations over the last year. People with poorer quality of life, bigger number of points on the Beck depression scale and DEFS, with lower levels of physical activity and worse endothelium-dependent vasodilator response; higher sizes of the right atrium, right ventricle, and pulmonary artery systolic pressure, E / E '. Higher levels of C-reactive protein (CRP), uric acid are associated with a risk of losing BW≥6 %. Conclusions. Weight loss ≥ 6 % is observed in 49.2 % of patients with CHF and LVEF≤35 %. According to multivariate analysis, independent predictors of BW loss of ≥6 % in patients with CHF and LVEF≤35 % are age, CRP level, III-IV NYHA class, lower cholesterol levels, as well as lower rates of flow-dependent vasodilator response and hip circumference.

Low skeletal muscle capillarization limits muscle adaptation to resistance exercise training in older adults

OBJECTIVES

Adequate muscle perfusion supports the transport of nutrients, oxygen and hormones into muscle fibers. Aging is associated with a substantial decrease in skeletal muscle capillarization, fiber size and oxidative capacity, which may be improved with regular physical activity. The aim of this study was to investigate the relationship between muscle capillarization and indices of muscle hypertrophy (i.e. lean mass; fiber cross sectional area (CSA)) in older adults before and after 12 weeks of progressive resistance exercise training (RET).

DESIGN

Interventional study SETTING AND PARTICIPANTS: 19 subjects (10 male and 9 female; 71.1 ± 4.3 years; 27.6 ± 3.2 BMI) were enrolled in the study and performed a whole body RET program for 12 weeks. Subjects where then retrospectively divided into a LOW or HIGH group, based on their pre-RET capillary-to-fiber perimeter exchange index (CFPE). Physical activity level, indices of capillarization (capillaries-to-fiber ratio, C:Fi; CFPE index and capillary-to-fiber interface, LC-PF index), muscle hypertrophy, muscle protein turnover and mitochondrial function were assessed before and after RET.

RESULTS

Basal capillarization (C:Fi; CFPE and LP-CF index) correlates with daily physical activity level (C:Fi, r = 0.57, p = 0.019; CFPE index, r = 0.55, p = 0.024; LC-PF index, r = 0.56, p = 0.022) and CFPE and LC-PF indices were also positively associated with oxidative capacity (respectively r = 0.45, p = 0.06; r = 0.67, p = 0.004). Following RET, subjects in the HIGH group underwent hypertrophy with significant improvements in muscle protein synthesis and muscle fiber CSA (p < 0.05). However, RET did not promote muscle hypertrophy in the LOW group, but RET significantly increased muscle capillary density (p < 0.05).

CONCLUSION/IMPLICATIONS

Muscle fiber capillarization before starting an exercise training program may be predictive of the muscle hypertrophic response to RET in older adults. Increases in muscle fiber size following RET appear to be blunted when muscle capillarization is low, suggesting that an adequate initial capillarization is critical to achieve a meaningful degree of muscle adaptation to RET.

Chronic exposure to fungicide propamocarb induces bile acid metabolic disorder and increases trimethylamine in C57BL/6J mice

Propamocarb (PM) is a widely used fungicide that affects lipid biosynthesis in fungi. In this study, we explored the effects of PM on mouse metabolism and gut microbiota-related pathways by exposing C57BL/6J mice to 1, 3, and 10 mg/L PM through drinking water for a duration of 10 weeks. We found that hepatic bile acids (BAs) were considerably increased in the PM-treated group. The transcription of genes related to BA synthesis and transportation were also markedly altered in the liver and the ileum; accordingly, serous BA profiles were changed. BAs are tightly associated with energy metabolism and the gut microbiota; as expected, we observed that hepatic glycolysis; β-oxidation; fatty acid transportation, release and synthesis; and triacylglycerol synthesis and transportation were significantly altered at the transcriptional level. Gut microbial community structures were significantly changed both in cecal contents and feces. Using Linear discriminant analysis Effect Size (LEfSe), we found that Chloroflexi, Bacteroidetes and Actinobacteria phyla; Prevotellaceae, Odoribacteraceae and Porphyromonadaceae families; and Butyricimonas, Oscillospira, Parabacteroides, Prevotella and Dorea genera enriched in PM-treated mice. Fecal metabolites involved in energy metabolism were likewise altered. In addition, the atherosclerosis-promoting molecule trimethylamine was significantly increased in feces, which induced a disturbance in the cardiac NO/NOS pathway and an increase in NF-κB transcriptional levels. Our findings indicated that chronic PM exposure induced disorders in enterohepatic metabolism and had potential to increase the risk of cardiovascular disease.

Searching for a mitochondrial root to the decline in muscle function with ageing

Sarcopenia, the age-related loss of muscle mass and strength, is linked to a range of adverse outcomes, such as impaired physical performance, cognitive function, and mortality. Preventing sarcopenia may reduce the burden of functional decline with aging and its impact on physiological and economic well-being in older adults. Mitochondria in muscle cells lose their intrinsic efficiency and capacity to produce energy during aging, and it has been hypothesized that such a decline is the main driver of sarcopenia. Oxidative phosphorylation becomes impaired with aging, affecting muscle performance, and contributing to an age-associated decline in mobility. However, it is unclear whether this deterioration is due to a reduced mitochondria population, decreased mitochondrial energetic efficiency, or a reduced capacity to dynamically transport oxygen and nutrients into the mitochondria, and addressing these questions is an active area of research. Further research in humans will require use of new "omics" technologies, progress in neuroimaging techniques that permit energy production assessment, and visualization of molecules critical for energetic metabolism, as well as proxy biomarkers of muscle perfusion.

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.

Sex Differences in the Associations between L-Arginine Pathway Metabolites, Skeletal Muscle Mass and Function, and their Responses to Resistance Exercise, in Old Age

OBJECTIVES

The current study was designed to explore the associations between L-arginine metabolites and muscle mass and function in old age, which are largely unknown.

DESIGN

The study used a randomised, double-blind, placebo-controlled design.

SETTING

The study was carried out in a laboratory setting.

PARTICIPANTS

50 healthy older adults [median age 70 years (IQR 67-73); 27 males].

INTERVENTION

Participants undertook an 18-week resistance exercise program, and a nutritional intervention (fish oil vs. placebo).

MEASUREMENTS

Serum homoarginine, ornithine, citrulline, asymmetric dimethylarginine (ADMA), NG-monomethyl-L-arginine (L-NMMA), and symmetric dimethylarginine (SDMA), maximal voluntary contraction (MVC) and isokinetic torque of the knee extensors at 30° s-1 (MIT), muscle cross sectional area (MCSA) and quality (MQ) were measured at baseline and after the intervention.

RESULTS

No significant exercise-induced changes were observed in metabolite concentrations. There were significant sex differences in the associations between metabolites and muscle parameters. After adjusting for age, glomerular filtration rate and fish oil intervention, citrulline (P=0.002) and ornithine (P=0.022) were negatively associated with MCSA at baseline in males but not females. However, baseline citrulline was negatively correlated with exercise-induced changes in MVC (P=0.043) and MQ (P=0.026) amongst females. Furthermore, amongst males, baseline homoarginine was positively associated with exercise-induced changes in MVC (P=0.026), ADMA was negatively associated with changes in MIT (P=0.026), L-NMMA (p=0.048) and ornithine (P<0.001) were both positively associated with changes in MCSA, and ornithine was negatively associated with changes in MQ (P=0.039).

CONCLUSION

Therefore, barring citrulline, there are significant sex differences in the associations between L-arginine metabolites and muscle mass and function in healthy older adults. These metabolites might enhance sarcopenia risk stratification, and the success of exercise programs, in old age.

Pre-sarcopenia is associated with renal hyperfiltration independent of obesity or insulin resistance: Nationwide Surveys (KNHANES 2008-2011)

Renal hyperfiltration is closely linked to cardiometabolic disorders, and it may increase the mortality risk of the general population. Despite the well-established association between cardiometabolic diseases and sarcopenia, the relationship between renal hyperfiltration and sarcopenia has not yet been assessed.This population-based, cross-sectional study used a nationally representative sample of 13,800 adults from the 2008 to 2011 Korea National Health and Nutrition Examination Survey. Renal hyperfiltration was defined as the age- and sex-specific glomerular filtration rate above the 90th percentile in subjects with normal kidney function (>60 mL/min/1.73 m). Appendicular skeletal muscle (ASM), measured by dual-energy x-ray absorptiometry, was used to assess pre-sarcopenia, which the international consensus defines as both ASM per se and ASM that was adjusted for the body mass index and the height.A total of 1402 (10.2%) participants were classified as having renal hyperfiltration. The prevalence of pre-sarcopenia ranged from 11.6% to 33.0%, by definition. Individuals with pre-sarcopenia had higher risks of renal hyperfiltration compared to those without pre-sarcopenia (10.9% vs 17.4%, P < .001; odds ratio [OR] = 1.71, 95% confidential interval [CI] = 1.48-1.99, P < .001). Multiple logistic regression analyses also demonstrated this independent association between pre-sarcopenia and renal hyperfiltration, following adjustment for confounding factors such as insulin resistance and obesity (OR = 1.84, 95% CI = 1.57-2.15, P < .001).In the general population of healthy individuals, pre-sarcopenia might be associated with renal hyperfiltration independent of obesity or insulin resistance.

Treatment of Obesity: Weight Loss and Bariatric Surgery

This review focuses on the mechanisms underlying, and indications for, bariatric surgery in the reduction of cardiovascular disease (CVD), as well as other expected benefits of this intervention. The fundamental basis for bariatric surgery for the purpose of accomplishing weight loss is the determination that severe obesity is a disease associated with multiple adverse effects on health, which can be reversed or improved by successful weight loss in patients who have been unable to sustain weight loss by nonsurgical means. An explanation of possible indications for weight loss surgery as well as specific bariatric surgical procedures is presented, along with review of the safety literature of such procedures. Procedures that are less invasive or those that involve less gastrointestinal rearrangement accomplish considerably less weight loss but have substantially lower perioperative and longer-term risk. The ultimate benefit of weight reduction relates to the reduction of the comorbidities, quality of life, and all-cause mortality. With weight loss being the underlying justification for bariatric surgery in ameliorating CVD risk, current evidence-based research is discussed concerning body fat distribution, dyslipidemia, hypertension, diabetes mellitus, inflammation, obstructive sleep apnea, and others. The rationale for bariatric surgery reducing CVD events is discussed and juxtaposed with impacts on all-cause mortalities. Given the improvement of established obesity-related CVD risk factors after weight loss, it is reasonable to expect a reduction of CVD events and related mortality after weight loss in populations with obesity. The quality of the current evidence is reviewed, and future research opportunities and summaries are stated.

Gender-Specific Associations between Low Skeletal Muscle Mass and Albuminuria in the Middle-Aged and Elderly Population

Objective This study assessed gender-specific associations between low muscle mass (LMM) and albuminuria. Methods Data from the Korea National Health and Nutrition Examination Survey 2011 were employed. The study consisted of 1,087 subjects (≥50 years old). Skeletal muscle index (SMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Mild LMM and severe LMM were defined as SMI that were 1-2 and >2 standard deviations below the sex-specific mean appendicular skeletal muscle mass of young adults, respectively. Increased albuminuria was defined as albumin-to-creatinine ratio ≥30mg/g Results Men with mild and severe LMM were significantly more likely to have increased albuminuria (15.2% and 45.45%, respectively) than men with normal SMI (9.86%, P<0.0001), but not women. Severe LMM associated independently with increased albuminuria in men (OR=7.661, 95% CI=2.72-21.579) but not women. Severe LMM was an independent predictor of increased albuminuria in hypertensive males (OR=11.449, 95% CI=3.037-43.156), non-diabetic males (OR=8.782, 95% CI=3.046-25.322), and males without metabolic syndrome (MetS) (OR=8.183, 95% CI=1.539-43.156). This was not observed in males without hypertension, males with diabetes or MetS, and all female subgroups. Conclusion Severe LMM associated with increased albuminuria in men, especially those with hypertension and without diabetes or MetS.

Frailty and sarcopenia as the basis for the phenotypic manifestation of chronic diseases in older adults

Frailty is a functional status that precedes disability and is characterized by decreased functional reserve and increased vulnerability. In addition to disability, the frailty phenotype predicts falls, institutionalization, hospitalization and mortality. Frailty is the consequence of the interaction between the aging process and some chronic diseases and conditions that compromise functional systems and finally produce sarcopenia. Many of the clinical manifestations of frailty are explained by sarcopenia which is closely related to poor physical performance. Reduced regenerative capacity, malperfusion, oxidative stress, mitochondrial dysfunction and inflammation compose the sarcopenic skeletal muscle alterations associated to the frailty phenotype. Inflammation appears as a common determinant for chronic diseases, sarcopenia and frailty. The strategies to prevent the frailty phenotype include an adequate amount of physical activity and exercise as well as pharmacological interventions such as myostatin inhibitors and specific androgen receptor modulators. Cell response to stress pathways such as Nrf2, sirtuins and klotho could be considered as future therapeutic interventions for the management of frailty phenotype and aging-related chronic diseases.

Sarcopenia Is Associated With Lower Skeletal Muscle Capillarization and Exercise Capacity in Older Adults

BACKGROUND

Skeletal muscle capillary rarefaction limits the transcapillary transport of nutrients and oxygen to muscle and may contribute to sarcopenia and functional impairment in older adults. We tested the hypothesis that skeletal muscle capillarization and exercise capacity (VO2max) are lower in sarcopenic than in nonsarcopenic older adults and that the degree of sarcopenia is related to lower skeletal muscle capillarization.

METHODS

Body composition, VO2max, and vastus lateralis capillarization were determined in 76 middle-aged and older men and women (age = 61±1 years, body mass index [BMI] = 30.7±0.5kg/m(2) [mean ± SEM]). Participants were classified as sarcopenic if appendicular lean mass divided by BMI (ALMBMI) was less than 0.789 for men or less than 0.512 for women.

RESULTS

Sarcopenic subjects (ALMBMI = 0.65±0.04, n = 16) had 20% lower capillary-to-fiber ratio, as well as 13% and 15% lower VO2max expressed as mL/kg/min or L/min, respectively, compared with sex-, race-, and age-matched participants without sarcopenia (ALMBMI = 0.81±0.05, n = 16; p < .05). In all 76 subjects, ALMBMI, thigh muscle cross-sectional area, and VO2max correlated directly with capillarization (r = .30-.37, p ≤ .05), after accounting for age, sex, and race.

CONCLUSIONS

These findings suggest that low skeletal muscle capillarization is one factor that may contribute to sarcopenia and reduced exercise capacity in older adults by limiting diffusion of substrates, oxygen, hormones, and nutrients. Strategies to prevent the aging-related decline in skeletal muscle capillarization may help to prevent or slow the progression of sarcopenia and its associated functional declines in generally healthy older adults.

Relationship Between Sarcopenia and Albuminuria: The 2011 Korea National Health and Nutrition Examination Survey

Studies have shown that albuminuria, obesity, and sarcopenia may share pathophysiological processes related to cardiovascular disease risk. Their direct relationships, however, have not been examined. This study investigated the association between albuminuria and sarcopenia in a representative fraction of the Korean population.Of the 10,589 people who participated in the 2011 Korea National Health and Nutrition Examination Survey, 2158 participants aged over 19 years had been tested for albumin-to-creatinine ratio and for body composition data using dual-energy x-ray absorptiometry. Albuminuria was defined as an albumin-to-creatinine ratio ≥30 mg/g. Sarcopenia was defined as a skeletal muscle index (SMI) (SMI (%) = total appendicular skeletal muscle mass [kg]/weight [kg] × 100) of less than 1 standard deviation (SD) (grade 1) or 2 SD (grade 2) below the sex-specific mean for a younger reference group.The prevalence of albuminuria was higher in those with grade 2 sarcopenia than in those with a normal SMI or grade 1 sarcopenia (33.3% versus 8.4% and 8.9%; P < 0.001). Conversely, grade 2 sarcopenia was also more prevalent in participants with albuminuria than in those with the upper tertile of normoalbuminuria. In addition, multiple logistic regression analysis showed the odds ratio for albuminuria risk in the grade 2 sarcopenia group was 2.93 (95% confidence interval [CI], 1.46-5.88), compared with normal SMI after adjusting for potential confounding factors, including the presence of obesity, diabetes, and hypertension. Moreover, individuals with albuminuria had an odds ratio of 3.39 (95% [confidence interval], 1.38-8.37) for grade 2 sarcopenia compared with those in the lowest tertile of normoalbuminuria.This is the first study to demonstrate that individuals with sarcopenia exhibited increased risk of albuminuria and vice versa.

Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial

Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (P<0·01) levels for FFM, BM, IQS and SMC with significantly lower (P<0·01) levels for FM. The effect was significantly more pronounced in subjects receiving collagen peptides: FFM (TG +4·2 (sd 2·31) kg/PG +2·9 (sd 1·84) kg; P<0·05); IQS (TG +16·5 (sd 12·9) Nm/PG +7·3 (sd 13·2) Nm; P<0·05); and FM (TG -5·4 (sd 3·17) kg/PG -3·5 (sd 2·16) kg; P<0·05). Our data demonstrate that compared with placebo, collagen peptide supplementation in combination with resistance training further improved body composition by increasing FFM, muscle strength and the loss in FM.

Chronic Intake of Sucrose Accelerates Sarcopenia in Older Male Rats through Alterations in Insulin Sensitivity and Muscle Protein Synthesis

BACKGROUND

Today, high chronic intake of added sugars is frequent, which leads to inflammation, oxidative stress, and insulin resistance. These 3 factors could reduce meal-induced stimulation of muscle protein synthesis and thus aggravate the age-related loss of muscle mass (sarcopenia).

OBJECTIVES

Our aims were to determine if added sugars could accelerate sarcopenia and to assess the capacity of antioxidants and anti-inflammatory agents to prevent this.

METHODS

For 5 mo, 16-mo-old male rats were starch fed (13% sucrose and 49% wheat starch diet) or sucrose fed (62% sucrose and 0% wheat starch diet) with or without rutin (5 g/kg diet), vitamin E (4 times), vitamin A (2 times), vitamin D (5 times), selenium (10 times), and zinc (+44%) (R) supplementation. We measured the evolution of body composition and inflammation, plasma insulin-like growth factor 1 (IGF-I) concentration and total antioxidant status, insulin sensitivity (oral-glucose-tolerance test), muscle weight, superoxide dismutase activity, glutathione concentration, and in vivo protein synthesis rates.

RESULTS

Sucrose-fed rats lost significantly more lean body mass (-8.1% vs. -5.4%, respectively) and retained more fat mass (+0.2% vs. -33%, respectively) than starch-fed rats. Final muscle mass was 11% higher in starch-fed rats than in sucrose-fed rats. Sucrose had little effect on inflammation, oxidative stress, and plasma IGF-I concentration but reduced the insulin sensitivity index (divided by 2). Meal-induced stimulation of muscle protein synthesis was significantly lower in sucrose-fed rats (+7.3%) than in starch-fed rats (+22%). R supplementation slightly but significantly reduced oxidative stress and increased muscle protein concentration (+4%) but did not restore postprandial stimulation of muscle protein synthesis.

CONCLUSIONS

High chronic sucrose intake accelerates sarcopenia in older male rats through an alteration of postprandial stimulation of muscle protein synthesis. This effect could be explained by a decrease of insulin sensitivity rather than by changes in plasma IGF-I, inflammation, and/or oxidative stress.

You're only as old as your arteries: translational strategies for preserving vascular endothelial function with aging

Endothelial dysfunction develops with age and increases the risk of age-associated vascular disorders. Nitric oxide insufficiency, oxidative stress, and chronic low-grade inflammation, induced by upregulation of adverse cellular signaling processes and imbalances in stress resistance pathways, mediate endothelial dysfunction with aging. Healthy lifestyle behaviors preserve endothelial function with aging by inhibiting these mechanisms, and novel nutraceutical compounds that favorably modulate these pathways hold promise as a complementary approach for preserving endothelial health.

Aerobic exercise and other healthy lifestyle factors that influence vascular aging

Cardiovascular diseases (CVDs) remain the leading cause of death in the United States and other modern societies. Advancing age is the major risk factor for CVD, primarily due to stiffening of the large elastic arteries and the development of vascular endothelial dysfunction. In contrast, regular aerobic exercise protects against the development of large elastic artery stiffness and vascular endothelial dysfunction with advancing age. Moreover, aerobic exercise interventions reduce arterial stiffness and restore vascular endothelial function in previously sedentary middle-aged/older adults. Aerobic exercise exerts its beneficial effects on arterial function by modulating structural proteins, reducing oxidative stress and inflammation, and restoring nitric oxide bioavailability. Aerobic exercise may also promote "resistance" against factors that reduce vascular function and increase CVD risk with age. Preventing excessive increases in abdominal adiposity, following healthy dietary practices, maintaining a low CVD risk factor profile, and, possibly, selective use of pharmaceuticals and nutraceuticals also play a major role in preserving vascular function with aging.

Low muscle mass in older men: the role of lifestyle, diet and cardiovascular risk factors

OBJECTIVE

To explore associations between low muscle mass and a wide range of lifestyle, dietary and cardiovascular risk factors in older men including metabolic risk factors, markers of inflammation, endothelial dysfunction and coagulation.

DESIGN

Cross-sectional study.

SETTING

British Regional Heart Study.

PARTICIPANTS

4252 men aged 60-79 years.

MEASUREMENTS

PARTICIPANTS attended a physical examination in 1998-2000, and completed a general questionnaire and a food frequency questionnaire. Low muscle mass was assessed by two measures: midarm muscle circumference (MAMC) and fat-free mass index (FFMI). Associations between risk factors and low muscle mass were analysed using logistic regression.

RESULTS

Physical inactivity, insulin resistance, C-reactive protein, von Willebrand factor and fibrinogen were associated with significantly increased odds of low MAMC and FFMI after adjustment for body mass index, lifestyle characteristics and morbidity. Those with higher percent energy intake from carbohydrates showed decreased odds of low MAMC (OR: 0.73, 95% CI: 0.55-0.96) and FFMI (OR: 0.76, 95% CI: 0.58-0.99). Other dietary variables, smoking, alcohol intake, D-dimer, interleukin 6 and homocysteine showed no important associations with MAMC and FFMI.

CONCLUSION

Increasing physical activity, consuming a diet with a high proportion of energy from carbohydrates, and taking steps to prevent insulin resistance and reduce inflammation and endothelial dysfunction may help to reduce the risk of low muscle mass in older men.

Sarcopenic obesity and endocrinal adaptation with age

In normal aging, changes in the body composition occur that result in a shift toward decreased muscle mass and increased fat mass. The loss of muscle mass that occurs with aging is termed sarcopenia and is an important cause of frailty, disability, and loss of independence in older adults. Age-related changes in the body composition as well as the increased prevalence of obesity determine a combination of excess weight and reduced muscle mass or strength, recently defined as sarcopenic obesity. Weight gain increases total/abdominal fat, which, in turn, elicits inflammation and fatty infiltration in muscle. Sarcopenic obesity appears to be linked with the upregulation of TNF-α, interleukin (IL)-6, leptin, and myostatin and the downregulation of adiponectin and IL-15. Multiple combined exercise and mild caloric restriction markedly attenuate the symptoms of sarcopenic obesity. Intriguingly, the inhibition of myostatin induced by gene manipulation or neutralizing antibody ameliorates sarcopenic obesity via increased skeletal muscle mass and improved glucose homeostasis. In this review, we describe the possible influence of endocrinal changes with age on sarcopenic obesity.