U-shaped association between plasma C-peptide and sarcopenia: A cross-sectional study of elderly Chinese patients with diabetes mellitus

Limited research exists regarding the relationship between fasting plasma C-peptide levels and sarcopenia. As a result, our study aimed to examine this association in elderly Chinese diabetic patients. This cross-sectional study included 288 elderly patients with diabetes mellitus from the Fourth People's Hospital in Guiyang who were enrolled prospectively between March 2020 and February 2023. The independent variable of interest was fasting plasma C-peptide, while the dependent variable was sarcopenia. Data on several covariates, including demographic factors, lifestyle habits, co-morbidities, anthropometric indicators, and laboratory indicators, were also collected. Of the 288 participants, 27.43% (79/288) had sarcopenia. After adjusting for potential confounding variables, we found a U-shaped association between fasting plasma C-peptide levels and sarcopenia, with inflection points identified at approximately 774 pmol/L and 939 mmol/L. Within the range of 50-744 pmol/L, each 100 pmol/L increase in CysC was associated with a 37% decrease in the odds of sarcopenia (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.49 to 0.83; P < 0.001). Additionally, within the range of 939-1694 pmol/L, each 100 pmol/L increase in fasting plasma C-peptide was associated with a 76% increase in the odds of sarcopenia (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.11 to 2.81; P = 0.017). Our study revealed a U-shaped association between fasting plasma C-peptide levels and the likelihood of sarcopenia, with lower risk in the range of 774-939 pmol/L. These findings may assist in the development of more effective prevention and treatment strategies for sarcopenia in elderly diabetic patients.

Lack of association between serum myonectin levels and sarcopenia in older Asian adults

Myonectin is a muscle-secreted factor that helps maintain homeostasis in the body by regulating several functions, including lipid metabolism. Previous studies suggested that myonectin may play a role in muscle health in an autocrine manner, but its impact on human skeletal muscle is still unclear. We aimed to investigate the relationship of serum myonectin levels with sarcopenia and related muscle parameters. We conducted a cross-sectional study of 142 older adults whose muscle mass, grip strength, gait speed, chair stands, and short physical performance battery (SPPB) were evaluated in the geriatric clinic of a tertiary medical center. Sarcopenia was defined based on Asian-specific cutoff values, and circulating myonectin levels were measured using an enzyme immunoassay. Before and after adjusting for age, sex, and body mass index, the serum myonectin level was not significantly different when the patients were stratified by status of sarcopenia, muscle mass, muscle strength, and physical performance. Furthermore, whether given as a continuous variable or divided into quartile groups, the serum myonectin level had no association with the skeletal muscle mass, grip strength, gait speed, chair stand test, or SPPB score. Our findings did not confirm the potential role of myonectin in muscle metabolism observed in experimental research. Thus, serum myonectin levels cannot predict the risk of sarcopenia in older Asian adults.

Metabolomics analysis reveals serum biomarkers in patients with diabetic sarcopenia

INTRODUCTION

Diabetic sarcopenia (DS) is characterized by muscle atrophy, slower nerve conduction, reduced maximum tension generated by skeletal muscle contraction, and slower contraction rate. Hence, DS can cause limb movement degeneration, slow movement, reduced balance, reduced metabolic rate, falls, fractures, etc. Moreover, the relevant early biological metabolites and their pathophysiological mechanism have yet to be characterized.

METHOD

The current cross-sectional study employed serum metabolomics analysis to screen potential noninvasive biomarkers in patients with diabetic sarcopenia. A total of 280 diabetic patients were enrolled in the study (n = 39 sarcopenia [DS], n = 241 without sarcopenia [DM]). Ten patients were randomly selected from both groups. Non-targeted metabolomic analysis was performed by ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

RESULTS

A total of 632 differential metabolites were identified, including 82 that were significantly differentially abundant (P < 0.05, VIP > 1, FC > 1.2 or FC < 0.8). Compared with the DM group, the contents of pentadecanoic acid, 5'-methylthioadenosine (5'-MTA), N,N-dimethylarginine (asymmetric dimethylarginine, ADMA), and glutamine in the DS group were significantly increased, while that of isoxanthohumol was decreased.

DISCUSSION

Based on receiver operating characteristic curve analysis, pentadecanoic acid, 5'-MTA, ADMA, and glutamine may serve as potential biomarkers of DS. Moreover, ATP-binding cassette (ABC) transporters and the mammalian target of the rapamycin signaling pathway were found to potentially have important regulatory roles in the occurrence and development of DS (P < 0.05). Collectively, the differential metabolites identified in this study provide new insights into the underlying pathophysiology of DS and serve as a basis for therapeutic interventions.

Low serum creatinine to cystatin C ratio is independently associated with sarcopenia and high carotid plaque score in patients with type 2 diabetes

BACKGROUND AND AIMS

Low serum creatinine (Cr) to cystatin C (cysC) ratio has been suggested to be associated with low muscle mass and strength and poor prognosis in various chronic disease. We investigated the associations of CCR with sarcopenia and carotid plaque score (PS) in patients with type 2 diabetes mellitus.

METHODS AND RESULTS

A total of 1577 patients with type 2 diabetes were enrolled. High PS was defined as PS ≥ 3. Sarcopenia was assessed by the measurement of appendicular skeletal muscle mass (ASM) and grip strength (GS). Compared to the highest CCR group, the lowest tertile group was older; had higher C-reactive protein levels, CIMT, and PS, but lower cysC-based estimated glomerular filtration rate (cysC-eGFR), ASM/BMI, and GS. Positive correlations between CCR and ASM/BMI (r = 0.239 in men and 0.303 in women, p < 0.001) and GS (r = 0.282 in men and 0.270 in women, p < 0.001) were observed in both genders. Odds ratios and 95% confidence intervals for high PS after adjusting for age and sex were 1.22 (0.92-1.61, p = 0.18) in the middle and 1.74 (1.31-2.30, p < 0.001) in the lowest tertiles, respectively, with those of the lowest tertile remaining significant after further adjusting for multiple confounders.

CONCLUSIONS

Low CCR was independently associated with sarcopenia and high PS in patients with type 2 diabetes mellitus, especially after adjusting for ASM/BMI and GS.

The effect of long-term hypogonadism on body composition and morphometry of aged male Wistar rats

Clinical studies show that hypogonadism in the aging male is associated with obesity and osteoporosis. Experimental studies are mostly conducted on relatively young adult animals and the induced hypogonadism lasts for a relatively short time. The present study aimed to describe the effect of long-term hypogonadism beginning in puberty on body composition, morphometry, and bone mineral density in aged male rats. Morphometric measurements and dual-energy X-ray absorptiometry were conducted at the age of 30 months on control and gonadectomized males. Long-term hypogonadism did not affect body weight, but led to a higher fat mass (by 26 %), lower lean mass (by 44 %), shorter body length (by 9 %), and anogenital distance (by 26 %), as well as to lower tail circumference (by 15 %) in comparison to control males. Lower bone mineral density (by 13 %) and bone mineral content (by 15 %) were observed in gonadectomized males. Results showing sarcopenic obesity and osteoporosis in this model of long-term hypogonadism might mimic the situation in aging males better than the widely used short-term hypogonadism induced in young animals. The morphometric analysis could potentially be a useful tool to study normal weight obesity without the need for specific equipment.

Gonadotropins at Advanced Age - Perhaps They Are Not So Bad? Correlations Between Gonadotropins and Sarcopenia Indicators in Older Adults

Many hormones fluctuate during the aging process. It has been suggested that gonadotropins, which increase with age, contribute to the occurrence of many diseases and syndromes in older life, such as cardiovascular diseases, obesity, frailty syndrome and osteoporosis. This study aims to assess the relationship between circulating gonadotropins and other hormones potentially contributing to age-related functional decline and sarcopenia indicators in 39 male and 61 female community-dwelling seniors, mean age 80 years. According to the definition developed by the second European Working Group on Sarcopenia in Older People (EWGSOP2), the following indicators of the sarcopenia were assessed: bioimpedance-measured body composition, gait speed, handgrip strength, timed up and go test (TUG), chair stand test, Short Physical Performance Battery (SPPB). Blood levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, testosterone, dehydroepiandrosterone sulphate (DHEAS) and cortisol were also measured. In the men, FSH and partially LH correlated positively with muscle mass percentage, gait speed, handgrip strength and SPPB, and negatively with percent body fat. Additionally, testosterone and DHEAS correlated negatively with the percentage of fat mass in men. Whereas in the women, FSH and LH were mainly negatively associated with body mass and adipose tissue measures. Cortisol did not show any relationship with the examined indicators. The study shows that the indicators of sarcopenia are strongly associated with levels of gonadotropins, sex hormones and DHEAS, especially in older men. The obtained results, after being confirmed in a larger group, may modify prevention and treatment strategies of sarcopenia.

Pathogenesis of Musculoskeletal Deficits in Children and Adults with Inflammatory Bowel Disease

Musculoskeletal deficits are among the most commonly reported extra-intestinal manifestations and complications of inflammatory bowel disease (IBD), especially in those with Crohn’s disease. The adverse effects of IBD on bone and muscle are multifactorial, including the direct effects of underlying inflammatory disease processes, nutritional deficits, and therapeutic effects. These factors also indirectly impact bone and muscle by interfering with regulatory pathways. Resultantly, individuals with IBD are at increased risk of osteoporosis and sarcopenia and associated musculoskeletal morbidity. In paediatric IBD, these factors may contribute to suboptimal bone and muscle accrual. This review evaluates the main pathogenic factors associated with musculoskeletal deficits in children and adults with IBD and summarises the current literature and understanding of the musculoskeletal phenotype in these patients.

Low creatinine levels in diabetes mellitus among older individuals: the Yuport Medical Checkup Center Study

ORIC ID

0000-0002-3401-8191. It is unknown whether the interrelationship between diabetes and muscle loss is affected by ageing. Therefore, the serum creatinine levels, an indicator of muscle mass, were compared between older people with diabetes and those without diabetes, using a cross-sectional dataset from the Yuport Medical Checkup Center Study. We classified 6133 participants without kidney dysfunction into three age-groups: early-elderly (65-69 years), middle-elderly (70-74 years), and late-elderly (≥ 75 years). The association between diabetes and the lowest creatinine level, defined as less than or equal to the 25 percentile of serum creatinine, was evaluated in each age group, by calculating the odds ratio (OR) using logistic regression. Serum creatinine levels increased with ageing in the participants, and these trends were markedly observed in the non-diabetic group. Late-elderly people with diabetes were significantly more likely to have low creatinine levels than those without diabetes, with adjusted ORs 2.50 (95% CI 1.99-4.50) in men and 2.88 (95% CI 1.47-5.64) in women. Ageing modified the effect of their diabetes status towards a lower creatinine level (p for interactions between the diabetic status and age-groups were 0.01 in men and 0.05 in women, respectively). Ageing may thus accelerate the loss of muscle mass in people with diabetes.

Irisin is a predictor of sarcopenic obesity in type 2 diabetes mellitus: A cross-sectional study

We aimed to evaluate sarcopenia and sarcopenic obesity (SO) in patients with type 2 diabetes mellitus (T2DM), possible relationships with serum irisin and myostatin levels, and the effect of glycemic control on SO.Ninety T2DM patients were included in this a cross-sectional study. Sarcopenia was determined by evaluating muscle mass (bioelectrical impedance analysis), muscle strength (HGS), and gait speed (GS). Patients with muscle mass loss with functionally reduced muscle strength and/or performance were considered sarcopenic. In addition, participants were divided into 3 groups according to the FM (fat mass)/FFM (fat-free mass) ratio [group 1:5th-50th percentiles; group 2:50th-95th percentiles and group 3: ≥95 percentiles (sarcopenic obese)]. Irisin, myostatin levels and metabolic parameters were measured in all patients.The prevalence of sarcopenia and SO was 25.6% and 35.6%, respectively. Irisin levels were lower in sarcopenic patients, while glycosylated hemoglobin (A1c), body mass index (BMI), FM, and FM index were higher (P < .05). From group 1 to group 3, BMI, FM, FM index, GS, myostatin, and A1c increased, and muscle mass percentage, HGS, and irisin decreased (P < .05). A positive correlation was found between FM/FFM and myostatin and a negative correlation between FM/FFM and irisin (r = 0.303, P = .004 vs. r = -0.491, P < .001). Irisin remained an important predictor of SO, even after adjusting for confounding variables (OR:1.105; 95% CI:0.965-1.338, P = .002). The optimal cut-off value for irisin to predict SO was 9.49 ng/mL (specificity = 78.1%, sensitivity = 75.8%). In addition, A1c was an independent risk factor for SO development (OR:1.358, P = .055).This study showed that low irisin levels (<9.49ng/mL) and poor glycemic control in T2DM patients were an independent risk factor, especially for SO.

The prognostic value of sarcopenia combined with preoperative fibrinogen-albumin ratio in patients with intrahepatic cholangiocarcinoma after surgery: A multicenter, prospective study

BACKGROUND

To explore the prognostic value of the fibrinogen-albumin ratio (FAR) combined with sarcopenia in intrahepatic cholangiocarcinoma (ICC) patients after surgery and to develop a nomogram for predicting the survival of ICC patients.

MATERIALS AND METHODS

In this prospective cohort study, 116 ICC patients who underwent radical surgery were enrolled as the discovery cohort and another independent cohort of 68 ICC patients was used as the validation cohort. Kaplan-Meier method was used to analyze prognosis. The independent predictor of overall survival (OS) and recurrence-free survival (RFS) was evaluated by univariable and multivariable Cox regression analyses, then developing nomograms. The performance of nomograms was evaluated by concordance index (C-index), calibration curve, receiver operating characteristic curve analysis (ROC), and decision curve analysis (DCA).

RESULTS

Patients with high FAR had lower OS and RFS. FAR and sarcopenia were effective predictors of OS and RFS. Patients with high FAR and sarcopenia had a poorer prognosis than other patients. OS nomogram was constructed based on age, FAR, and sarcopenia. RFS nomogram was constructed based on FAR and sarcopenia. C-index for the nomograms of OS and RFS was 0.713 and 0.686. Calibration curves revealed great consistency between actual survival and nomogram prediction. The area under ROC curve (AUC) for the nomograms of OS and RFS was 0.796 and 0.791 in the discovery cohort, 0.823 and 0.726 in the validation cohort. The clinical value of nomograms was confirmed by the DCA.

CONCLUSIONS

ICC patients with high FAR and sarcopenia had a poor prognosis, the nomograms developed based on these two factors were accurate and clinically useful in ICC patients who underwent radical resection.

Association of mean corpuscular volume with sarcopenia and visceral obesity in individuals without anemia

AIMS/INTRODUCTION

Sarcopenia and visceral obesity are major global public health issues, and higher mean corpuscular volume (MCV) levels are related to adverse outcomes. Nevertheless, no study has determined the association between MCV and body composition. Therefore, we evaluated the association between MCV levels and trunk muscle quality, muscle quantity and visceral fat area.

MATERIALS AND METHODS

In our cross-sectional study, we investigated 702 middle-aged Japanese individuals without anemia and with normal MCV levels who underwent physical checkups. The cross-sectional area of skeletal muscle or visceral fat was analyzed by computed tomography.

RESULTS

In the adjusted model, the MCV was independently associated with the visceral fat area index (β = -0.107, P = 0.0007), total skeletal muscle index (β = 0.053, P = 0.0341) and total skeletal muscle density (β = 0.099, P = 0.0012). MCV as a continuous variable was related to the prevalence of sarcopenia (odds ratios [OR] 0.93, 95% confidence intervals (CI) 0.88-0.98, per 1.0 fL increment; P = 0.0097) and visceral obesity (OR 0.91, 95% CI 0.86-0.97, per 1.0 fL increment; P = 0.0046). The highest MCV quartile was independently associated with the prevalence of sarcopenia (OR 0.48, 95% CI 0.27-0.83; P = 0.0089) and visceral obesity (OR 0.49, 95% CI 0.27-0.88; P = 0.0170), compared with the lowest quartile.

CONCLUSIONS

In individuals without anemia and with normal MCV levels, a lower MCV was associated with unfavorable body composition, including lower muscle quality, lower muscle quantity, sarcopenia and visceral obesity.

Relationship between Serum Alkaline Phosphatase and Low Muscle Mass Index Among Korean Adults: A Nationwide Population-Based Study

Sarcopenia has attracted interest due to its impact on various health problems. Chronic inflammation is an important contributor to sarcopenia. Thus, we aimed to investigate the association between serum alkaline phosphatase (ALP), which is a novel inflammatory marker, and muscle mass. This study included 15,579 adults from the 2008–2011 Korea National Health and Nutrition Survey. Low skeletal muscle mass index (LSMI) was defined as body mass index-adjusted appendicular skeletal muscle mass less than 0.789 for men and 0.512 for women. Multiple logistic regression revealed that the highest ALP tertile was significantly associated with LSMI compared with the lowest ALP tertile in both men [Odds ratio (OR): 1.41; 95% confidence interval (CI): 1.04–1.91] and women (OR: 1.45; 95% CI: 1.00–2.10) after adjusting for other confounders. On the receiver operating characteristic curve analysis, the predictive power was significantly higher for ALP levels than for white blood cell count in women (p < 0.001), whereas the difference was not significant in men (p = 0.515). Our findings suggest the potential use of serum ALP as an inflammatory marker and a predictor of sarcopenia.

Serum creatinine to cystatin C ratio is associated with major adverse cardiovascular events in patients with obstructive coronary artery disease

BACKGROUND & AIMS

Sarcopenia is a clinical syndrome that features muscle atrophy and weakness, and has been associated with cardiovascular events and poor clinical outcomes. Recently, the sarcopenia index (SI) was developed as a simple screening tool based upon the serum creatinine to cystatin C (CysC) ratio. We investigated the association between SI and the prevalence of major adverse cardiovascular events (MACE) in patients with obstructive CAD.

METHODS & RESULTS

Between January 2010 and December 2018, patients with angina pectoris and obstructive CAD requiring coronary artery intervention were enrolled. Serum levels of CysC and other biomarkers were assessed. Patients were divided into two groups according to the SI ([Cr/CysC] x 100). Demographic characteristics and clinical outcomes of the two groups were evaluated. A total of 427 patients (79.6% men, mean age 69.55 ± 12.04 years) were enrolled. Patients with SI < 120 (n = 214, 28%) were older, more likely to be of the female gender, and to have more hypertension and congestive heart failure (all p < 0.05). The prevalence of major adverse cardiovascular events (MACE) composed of myocardial infarction, stroke, and all-cause mortality was higher in patients with lower SI (p = 0.026). After adjusting for potential confounding factors, multivariate Cox regression (hazard ratio 2.08, p = 0.045) and Kaplan-Meier analyses (log-rank p = 0.0371) revealed that lower SI was significantly associated with a higher prevalence of MACE.

CONCLUSIONS

Serum creatinine to cystatin C ratio (SI) may be a useful surrogate marker to predict the future prevalence of MACE in patients with obstructive CAD.

Vitamin D Deficiency in Older Patients-Problems of Sarcopenia, Drug Interactions, Management in Deficiency

Vitamin D deficiency frequently occurs in older people, especially in individuals with comorbidity and polypharmacotherapy. In this group, low vitamin D plasma concentration is related to osteoporosis, osteomalacia, sarcopenia and myalgia. Vitamin D levels in humans is an effect of the joint interaction of all vitamin D metabolic pathways. Therefore, all factors interfering with individual metabolic stages may affect 25-hydroxyvitamin D plasma concentration. The known factors affecting vitamin D metabolism interfere with cytochrome CYP3A4 activity. There is another group of factors that impairs intestinal vitamin D absorption. The phenomenon of drugs and vitamin D interactions is observed first and foremost in patients with comorbidity. This is a typical situation, where the absence of "hard evidence" is not synonymous with the possible lack of adverse effects. Osteoporosis and sarcopenia (generalized and progressive decrease of skeletal muscle mass and strength) are some of the musculoskeletal consequences of hypovitaminosis D. These consequences are related to an increased risk of adverse outcomes, including bone fractures, physical disabilities, and a lower quality of life. This can lead not only to an increased risk of falls and fractures but is also one of the main causes of frailty syndrome in the aging population. Generally, Vitamin D plasma concentration is significantly lower in subjects with osteoporosis and muscle deterioration. In some observational and uncontrolled treatment studies, vitamin D supplementation resulted in a reduction of proximal myopathy and muscle pain. The most conclusive results were found in subjects with severe vitamin D deficiency and in patients avoiding large doses of vitamin D. However, the role of vitamin D in muscle pathologies is not clear and research has provided conflicting results. This is plausibly due to the heterogeneity of the subjects, vitamin D doses and environmental factors. This report presents data on some problems with vitamin D deficiency in the elderly population and the management of vitamin D deficiency D in successful or unsuccessful aging.

Disentangling Associations Between Serum Muscle Biomarkers and Sarcopenia in the Presence of Pain and Inflammation Among Patients With Osteoarthritis: The SPSS-OK Study

BACKGROUND/OBJECTIVE

Reduction of muscle markers, such as creatine phosphokinase (CK), in rheumatic diseases and its association with reduced muscle mass may be of clinical importance in osteoarthritis (OA). Considering the complexity of secondary sarcopenia, clarifying the association between muscle markers and sarcopenia and disentangling the involvement of OA-related conditions are of clinical importance. We investigated the association between serum muscle biomarkers and sarcopenia among patients with OA, considering the presence of pain and inflammation.

METHODS

Overall, 1425 patients with knee and hip OA scheduled for joint replacement surgery were included in a single-center cross-sectional study from Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study. Primary outcome was sarcopenia defined by 2 criteria (the Asian Working Group for Sarcopenia and the European Working Group on Sarcopenia in Older People). Pain and inflammation were measured using the numeric rating scale and serum C-reactive protein (CRP) levels, respectively. Associations between the biomarkers (serum CK, aspartate aminotransferase, alanine aminotransferase) and sarcopenia were examined using logistic regression models.

RESULTS

Sarcopenia by the Asian Working Group for Sarcopenia criteria was present in 4.0% of patients. In adjusted analyses, sarcopenia was negatively associated with higher serum CK levels, but not with serum aspartate aminotransferase or alanine aminotransferase levels independent of pain score and serum CRP. Neither pain score nor serum CRP level was associated with sarcopenia. Similar results were found when the European Working Group on Sarcopenia in Older People criteria were used.

CONCLUSIONS

Serum CK was associated with sarcopenia, suggesting the potential usefulness for sarcopenia detection regardless of pain or inflammation in OA.

The Relationship between Sarcopenia and Vitamin D Levels in Adults of Different Ethnicities: Findings from the West China Health and Aging Trend Study

OBJECTIVES

Sarcopenia is a condition associated with progressive loss of skeletal muscle mass and function resulting in substantial negative health outcomes and disability in older adults. It is thus important that sarcopenia-related risk factors be explored. The present study was based upon the Asian Working Group on Sarcopenia 2019 (AWGS2019) criteria to assess whether vitamin D levels are a risk factor associated with sarcopenia in various ethnic groups in western China.

DESIGN

Cross-sectional study.

SETTING

Communities in Yunnan, Guizhou, Sichuan, and Xinjiang provinces.

PARTICIPANTS

We included 4236 individuals that were 50 years of age or older from the West China Health and Aging Trend (WCHAT) study.

MEASUREMENTS

An InBody 770 instrument was used for bioimpedance-based analyses of muscle mass, while a digital grip strength dynamometer was used for handgrip strength-based measurements of muscle strength. Physical performance was assessed based upon gait speed over 4 m. Other secondary variables were additionally analyzed as potentially relevant risk factors.

RESULTS

Sarcopenia affected an estimated 22.45% of studied individuals who were 50 years of age or older, with respective prevalence rates in the < 60, 60-64, 65-79, and ≥80 age groups of 11.78%,19.44%, 32.65%, and 67.97%. Rates in males and females were 26.66% and 20.05%, respectively. In males, a significant difference in vitamin D levels was detected when comparing individuals with and without sarcopenia, although no such relationship was detected in females. Following adjustment for confounding variables, binary logistic regression analyses revealed that inadequate vitamin D was able to independently predict sarcopenia risk only in males (OR=1.875,95%CI: 1.109-3.169, P=0.019).

CONCLUSIONS

Among middle-aged and older adults of multiple ethnicities in western China, we found that inadequate vitamin D was an independent predictor of sarcopenia risk specifically in males.

Muscle mass and plasma myostatin after exercise training: a substudy of Renal Exercise (RENEXC)-a randomized controlled trial

BACKGROUND

Sarcopenia increases as renal function declines and is associated with higher morbidity and mortality. Myostatin is a negative regulator of muscle growth. Its expression in response to exercise is unclear. In this prespecified substudy of the Renal Exercise (RENEXC) trial, we investigated the effects of 12 months of exercise training on sarcopenia, muscle mass and plasma myostatin and the relationships between physical performance, muscle mass and plasma myostatin.

METHODS

A total of 151 non-dialysis-dependent patients (average measured glomerular filtration rate 23 ± 8 mL/min/1.73 m2), irrespective of age or comorbidity, were randomly assigned to either strength or balance in combination with endurance training. Body composition was measured with dual-energy X-ray absorptiometry. Plasma myostatin was analysed using enzyme-linked immunosorbent assay kits.

RESULTS

After 12 months, the prevalence of sarcopenia was unchanged, leg and whole-body lean mass increased significantly in the balance group and was unchanged in the strength group. Whole fat mass decreased significantly in both groups. There were no significant between-group differences in sarcopenia or body composition. Plasma myostatin levels increased significantly in both groups, with a significant difference in favour of the strength group. Plasma myostatin was significantly positively related to muscle mass and physical performance at baseline, but these relationships were attenuated after 12 months.

CONCLUSIONS

Exercise training seems to be effective in preventing sarcopenia and maintaining muscle mass in non-dialysis-dependent patients with chronic kidney disease (CKD). However, the role of plasma myostatin on muscle mass and physical performance in patients with CKD warrants further study.

Distinct determinants of muscle wasting in nonobese heart failure patients with and without type 2 diabetes mellitus

BACKGROUND

Muscle wasting, that is, reduction in muscle mass, is frequently observed in patients with chronic heart failure (CHF) and diabetes mellitus (DM).

METHODS

We retrospectively examined 185 patients with CHF (median age of 71 years [interquartile range, 61-78 years]; 64% male) who received a dual-energy X-ray absorptiometry scan for assessment of appendicular skeletal muscle mass index (ASMI).

RESULTS

Seventy patients with CHF (38%) had DM. Patients with DM had higher prevalences of ischemic heart disease and hypertension, lower levels of estimated glomerular filtration rate (eGFR) and ASMI, and higher levels of plasma renin activity (PRA) than did patients without DM. In simple regression analyses, ASMI was positively correlated with the Mini Nutritional Assessment Short Form (MNA-SF) score and levels of hemoglobin, eGFR, and fasting plasma insulin and was negatively correlated with levels of N-terminal pro B-type natriuretic peptide, PRA, and cortisol. In multiple linear regression analyses, age, MNA-SF score, DM, fasting plasma insulin level, and PRA were independently associated with ASMI. When multiple linear regression analyses were separately performed in a non-DM group and a DM group, MNA-SF score and fasting plasma insulin level were independent variables for ASMI in both groups. PRA was independently associated with ASMI in the DM group but not in the non-DM group, whereas cortisol concentration was independently associated with ASMI only in the non-DM group.

CONCLUSIONS

In addition to malnutrition and reduction in plasma insulin, renin-angiotensin system activation may be responsible for the development of muscle wasting in CHF patients with DM.

Diagnostic Performance of Clinical Laboratory Indicators With Sarcopenia: Results From the West China Health and Aging Trend Study

BACKGROUND

Sarcopenia is an age-related and skeletal muscle disorder involving the loss of muscle mass or strength, and physiological function. Although the diagnostic indicators used in the different guidelines are for muscle mass, strength and physical performance, there are currently no uniform diagnostic criteria. Therefore, we aimed to explore the relationship between a series of biomarkers with sarcopenia in southwest China.

METHODS

We included 4302 patients from West China Health and Aging Trend (WCHAT) study. Sarcopenia was defined according to the Asian Working Group for Sarcopenia: 2019 Consensus Update on Sarcopenia Diagnosis and Treatment. Thyroxine、albumin、total protein、prealbumin、albumin to globulin ratio (A/G)、25(OH)VD、fasting insulin、adrenal cortisol、triglyceride、high-density lipoprotein、hemoglobin and aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT) were measured. The receiver operating characteristic curves (ROC) were established to describe the predictive value for sarcopenia and we also used multivariate logistic regression analysis to identify risk factors of the disease.

RESULTS

In terms of protein state, patients with sarcopenia had lower value in total protein, albumin, prealbumin, A/G than the control (P<0.001). Patients had lower value in triglyceride but higher value in high-density lipoprotein compared with the healthy in the indicators of lipid metabolism (P<0.001). In the aspect of hormone state, patients had lower free triiodothyronine, fasting insulin but higher free tetraiodothyronine and adrenal cortisol than the healthy (P<0.001). The fasting insulin level (AUC=0.686) and the AST/ALT ratio (AUC=0.682) were the best predictors of sarcopenia among biomarkers. The diagnostic performance of fasting insulin combined with the AST/ALT ratio (AUC=0.720) is equal to multiple indicators (AUC=0.742).

CONCLUSION

The fasting insulin combined with the AST/ALT ratio exhibits good diagnostic performance for sarcopenia.

The Role of Baseline Sarcopenia Index in Predicting Chemotherapy-Induced Undesirable Effects and Mortality in Older People with Stage III or IV Non-Small Cell Lung Cancer

OBJECTIVES

To assess the predictability value of Sarcopenia index( (SI, serum creatinine value/cystatin C value×100) in determining potential chemotherapy-induced undesirable reactions and eventual death of older patients diagnosed with stage III or IV of non-small cell lung cancer (NSCLC).

METHODS

General information was retrieved from health records and mortality data was obtained by phone interview. Serum Cr and CysC levels were measured before chemotherapy. The endpoints recorded were chemotherapy-induced undesirable reactions and mortality from any causes. Logit regression analysis was employed for the analysis of correlation between the SI and short-term adverse reactions to chemotherapy. Cox regression analysis was employed to analyze correlation between the SI and mortality.

RESULTS

In this study, 664 NSCLC patients were enrolled. Among them, 83.13% were diagnosed with adenocarcinoma lung cancer and 16.87% with squamous cell carcinoma lung cancer. As of March 1, 2019, 486 patients died, including 361(74.28%) males and 125 (25.72%) females. After the first course of chemotherapy, the proportion of short-term adverse reactions, including bone marrow suppression, digestive reactions, all infection, liver function impairment, and other adverse reactions (non-infectious fever or rashes) was 16%, 4.7%, 7.4, %, 6.6%, and 2.11%, respectively. After adjusting for confounding factors, there was no association between the SI and adverse reactions. We found that high SI was independently associated with a lower risk of mortality after adjusting for confounding factors in females (HR=0.593,95% CI: 0.382-0.92; p=0.02). There was no marked association existed between the SI and mortality in males.

CONCLUSION

Among patients with stage III or IV non-small cell lung cancer, the SI is associated with mortality in females, but not in males.

Sex-Specific Differences in the Effect of Free Testosterone on Sarcopenia Components in Older Adults

OBJECTIVE

The association of free testosterone (FT) with sarcopenia and its components is well known in men but incompletely understood in women. We examined the association of baseline FT with the prevalence and incidence of sarcopenia and its components in community-dwelling older adults.

DESIGN

Cross-sectional and longitudinal analysis from the prospective population-based Korean Frailty and Aging Cohort Study.

METHODS

A total of 1,879 community-dwelling older adults aged 70-84 years were enrolled for cross-sectional analysis and 1,583 subjects who participated in the 2-year follow-up survey were included for longitudinal analysis. Baseline FT levels was measured by radioimmunoassay. Skeletal muscle mass, handgrip strength, and physical performance tests were measured at baseline and after 2-year follow-up. Sarcopenia was defined by the diagnostic criteria of the Asian Working Group for Sarcopenia (AWGS).

RESULTS

Continuous FT levels was positively associated with the prevalence of sarcopenia in men (odds ratio [OR]=0.95; 95% confidence interval [CI]=0.89-1.00)] and women (OR=0.64, 95% CI=0.42-0.99) after adjusting for multiple confounders. In prospective analysis, low FT levels was associated with a decrease in handgrip strength in women (β=-0.61; p=0.010) and a reduction in Timed "Up and Go" (TUG) test (β=0.53; p=0.008) in men after 2 years. No significant correlations were found between FT levels and the incidence of sarcopenia.

CONCLUSIONS

Low levels of FT may be a significant determinant of decreases in muscle strength in women and declines in physical performance in men after 2 years. Low FT do not predict loss of muscle mass in both men and women.

Adiponectin and Sarcopenia: A Systematic Review With Meta-Analysis

BACKGROUND

Sarcopenia is a progressive loss of skeletal muscle mass whose pathophysiology has been proposed to possibly involve mechanisms of altered inflammatory status and endocrine function. Adiponectin has been shown to modulate inflammatory status and muscle metabolism. However, the possible association between adiponectin levels and sarcopenia is poorly understood. In order to fill this gap, in the present manuscript we aimed to summarize the current evidence with a systematic review and a meta-analysis of studies reporting serum adiponectin levels in patients with sarcopenia compared to non-sarcopenic controls.

METHODS

An electronic search through Medline/PubMed, Cochrane Library, and Science Direct was performed till March 1, 2020. From the included papers, meta-analysis of cross-sectional studies comparing serum levels of adiponectin between patients with sarcopenia and controls was performed.

RESULTS

Out of 1,370 initial studies, seven studies were meta-analyzed. Sarcopenic participants had significantly higher levels of adiponectin Hedges' g with 95% confidence interval (CI): 1.20 (0.19-2.22), p = 0.02 than controls. Subgroup analysis, performed in Asian population and focused on identification of the condition based on AWGS criteria, reported higher adiponectin levels in sarcopenic population (2.1 (0.17-4.03), p = 0.03 and I2 = 98.98%. Meta-regression analysis revealed female gender to significantly influence the results as demonstrated by beta = 0.14 (95% CI (0.010-0.280), p = 0.040).

CONCLUSIONS

Our meta-analysis found evidence that sarcopenia is associated with higher adiponectin levels. However, caution is warranted on the interpretation of these findings, and future longitudinal research is required to disentangle and better understand the topic.

Effect of Thyroid-Stimulating Hormone Suppression on Muscle Function After Total Thyroidectomy in Patients With Thyroid Cancer

CONTEXT

Thyroid-stimulating hormone (TSH) suppression is recommended to reduce tumor recurrence following surgery for differentiated thyroid cancer (DTC). However, prolonged subclinical hyperthyroidism caused by levothyroxine treatment has deleterious effects on various organs.

OBJECTIVE

To evaluate the relationships of TSH concentration with muscle mass, muscle strength, and physical performance related to sarcopenia in patients with DTC undergoing TSH suppression following surgery.

METHODS

We studied 134 patients of >60 years who were undergoing TSH suppression therapy following surgery for DTC. We evaluated muscle mass and muscle function-related parameters and diagnosed sarcopenia using the threshold for Asian people.

RESULTS

The participants were 68.3 ± 7.2 years old and 36/134 (26.9%) were diagnosed with sarcopenia. They were allocated to high-TSH and low-TSH groups using a threshold concentration of 0.40 μU/mL, and grip strength was significantly lower in the low-TSH group. The data were further analyzed according to age and sex, and in the low-TSH group, male participants and those of <70 years were found to have significantly lower grip strength.

CONCLUSIONS

Low-TSH concentrations is associated with low grip strength, and this is most pronounced in individuals of <70 years of age. Therefore, muscle function should be considered an adverse effect of TSH suppression in patients with DTC who undergo TSH suppression therapy, especially in men of <70 years.

The Association Between Diabetes Mellitus and Risk of Sarcopenia: Accumulated Evidences From Observational Studies

AIM

We performed a meta-analysis of observational studies to evaluate the association between the presence of sarcopenia and HbA1c, prediabetes, diabetes and diabetic complications.

METHOD

The PubMed, Embase, Cochrane and Web of Science databases were searched from inception to May 2021. We included full-text English language articles that reported the prevalence of sarcopenia in patients with and without diabetes. Quality assessment was performed according to the Newcastle- Ottawa scale for observational studies.

RESULTS

Sixteen studies were included in the meta-analysis. Three studies showed that high HbA1c levels lead to loss of muscle mass, and one study involving prediabetes showed that people with prediabetes had lower muscle mass, strength, and performance than non-diabetic population. Seven studies showed that people with diabetes had a higher risk of sarcopenia than those without diabetes (combined OR: 2.09, 95% CI:1.62-2.70). The remaining five studies suggested that diabetic complications increased the risk of sarcopenia (combined OR: 2.09,95% CI:1.62-2.70).

CONCLUSION

High HbA1c levels, prediabetes, diabetes and diabetes complications were associated with an increased risk of sarcopenia. Therapeutic strategies addressed to avoid the conversion of IGT to diabetes and to optimize glycemic control are warranted to prevent or arrest sarcopenia in the diabetic population.

Biomarkers of Physical Frailty and Sarcopenia: Coming up to the Place?

Physical frailty and sarcopenia (PF&S) recapitulates all the hallmarks of aging and has become a focus in geroscience. Factors spanning muscle-specific processes (e.g., mitochondrial dysfunction in skeletal myocytes) to systemic changes (e.g., inflammation and amino acid dysmetabolism) have been pinpointed as possible contributors to PF&S pathophysiology. However, the search for PF&S biomarkers allowing the early identification and tracking of the condition over time is ongoing. This is mainly due to the phenotypic heterogeneity of PF&S, its unclear pathophysiology, and the frequent superimposition of other age-related conditions. Hence, presently, the identification of PF&S relies upon clinical, functional, and imaging parameters. The adoption of multi-marker approaches (combined with multivariate modeling) has shown great potential for addressing the complexity of PF&S pathophysiology and identifying candidate biological markers. Well-designed longitudinal studies are necessary for the incorporation of reliable biomarkers into clinical practice and for unveiling novel targets that are amenable to interventions.

Creatinine/(cystatin C × body weight) ratio is associated with skeletal muscle mass index

We have previously reported that the creatinine (Cre) to cystatin C (CysC) ratio is associated with height-adjusted skeletal muscle mass index (SMI). However, weight-adjusted SMI is reported to be a more useful marker of insulin sensitivity than height-adjusted SMI. Thus, we hypothesized that the creatinine to (cystatin C × body weight [BW]) relationship (Cre/[CysC × BW]) might be associated with weight-adjusted SMI. In this cross-sectional study of 169 males and 132 females, a body composition analyzer was used and the weight-adjusted SMI was calculated as (absolute muscle mass [kg]/BW [kg]) × 100. The cut-off of low muscle mass was defined as weight-adjusted SMI <37.0% for males and <28.0% for females. The Cre/(CysC × BW) was correlated with weight-adjusted SMI in both males (r = 0.484, p < 0.001) and females (r = 0.538, p < 0.001). In addition, Cre/(CysC × BW) was associated with weight-adjusted SMI in both males (standardized β = 0.493, p < 0.001) and females (standardized β = 0.570, p < 0.001) after adjusting for covariates. According to the receiver operator characteristic (ROC) curve analysis, the optimal cut-off point of Cre/(CysC × BW) for low muscle mass was 0.0145 (area under the ROC curve [AUC] 0.756 [95% confidence interval {95% CI} 0.644-0.842], sensitivity = 0.96, specificity = 0.47, p < 0.001) in males and 0.0090 (AUC 0.976 [95% CI 0.894-0.995], sensitivity = 1.00, specificity = 0.93, p < 0.001) in females. There is a correlation between Cre/(CysC × BW) and weight-adjusted SMI. The Cre/(CysC × BW) could be a practical screening marker for low muscle mass.

Prehabilitation: metabolic considerations

PURPOSE OF REVIEW

The major components of ERAS attenuate the inflammatory response and modulate metabolism in direction of sparing body protein and preserving function. However, these perioperative interventions might have limited effectiveness on postoperative outcomes if preoperative risk factors are not addressed and optimized.

RECENT FINDINGS

The preoperative metabolic perturbations characterized by insulin resistance and sarcopenia might predispose patients to a higher degree of postoperative catabolism. High-risk populations for such metabolic disturbances include elderly and frail patients, and patients with metabolic syndrome. Research on the effect of prehabilitation on perioperative metabolism is limited, but recent findings suggest that interventions designed to improve insulin sensitivity prior to surgery might represent a promising therapeutic target to minimize surgical complications.

SUMMARY

The present paper will discuss the metabolic implications of modulating preoperative risk factors with elements of multimodal prehabilitation, such as exercise training and nutrition.

Expression Patterns of Muscle-Specific miR-133b and miR-206 Correlate with Nutritional Status and Sarcopenia

Sarcopenia and malnutrition are commonly occurring conditions in the elderly that frequently coexist, leading to substantial effects on morbidity/mortality. Evidence established muscle-specific microRNAs (miRNAs) or myomiRs as essential regulators of skeletal muscle processes, from myogenesis to muscle homeostasis. This study aimed to evaluate the association between myomiRs and sarcopenia and explore the potential of nutrition in mediating this association. qPCR was employed to characterize the myomiR-1, -133a/b, -206, -208b, and -499 expression profiles of 109 non-sarcopenic and 109 sarcopenic subjects. In our sample, the proportion malnourished or at-risk subjects was higher in sarcopenia (p < 0.001). Among the detected myomiRs (miR-133a/b and miR-206), lower levels of miR-133b was significantly associated with the presence of sarcopenia (p = 0.006); however, this relationship was not independent from nutritional status in multivariate analysis, suggesting a mediating effect of nutrition on the relationship between miR-133b and sarcopenia. Correlation analyses showed that lower miR-133b levels were associated with poor nutritional status (Mini Nutritional Assessment Long Form (MNA-LF) score, p = 0.005); furthermore, correlations with albumin, ferritin, and iron were found. Similar results were obtained for miR-206. Statistically more significant correlations were observed in subjects with sarcopenia. In conclusion, our findings highlight a nutrient-miR-133b/miR-206 pathway having a potential role in the age-related muscle decline.

The Effects of Concurrent Training Order on Satellite Cell-Related Markers, Body Composition, Muscular and Cardiorespiratory Fitness in Older Men with Sarcopenia

OBJECTIVES

Concurrent Training (CT) is described as a combination of resistance training (RT) and endurance training (ET) in a periodized program to maximize all aspects of physical performance. To date, effects of CT order on muscular and cardiorespiratory fitness adaptations are controversial. Owing to the age-related decrement in satellite cells (SC) which are critical for fiber repair, conservation, muscle hypertrophy as well as cardiorespiratory fitness, the present study examined the response of SC related markers to CT order in older sarcopenic men.

PARTICIPANTS

Thirty older men (age= 64.3 ± 3.5 years) were randomly assigned into one of 3 groups, ET followed by RT (E+R; n=10), RT followed by ET (R+E; n= 10) or a control (C; n=10).

INTERVENTION

The training protocol consisted of 3 exercise sessions per week for 8 weeks. Blood samples were obtained at baseline and 48 hours after the final training session.

RESULTS

Weight, skeletal muscle mass, lower and upper body power, maximal oxygen consumption (VO2max), Paired Box 7 (Pax7), and Myogenic factor 5 (Myf5) significantly increased, while were percent body fat significantly decreased following E+R and R+E compared to C. Importantly, the improvement in skeletal muscle mass, lower and upper body power, Myf5 and Pax7 in the E+R was significantly greater than the R+E group. Myogenin (Myog) and Paired Box 3 (Pax3) significantly increased (P < 0.01) in both training groups compared to no changes in C.

CONCLUSION

An 8-week CT intervention improves SC related markers, body composition and enhances power and VO2max in older sarcopenic participants, regardless of the order of RT and ET. However, performing ET before RT may be more effective at enhancing skeletal muscle mass, Myf5 and Pax7, in addition to both lower and upper body power. While both CT programs produced notable physiological and performance benefits, performing ET before RT during CT may provide the greatest therapeutic benefits for aging individuals.

Multiplex Analysis of Circulating Hormone Levels in Rat Models of Age-Related Diseases

This chapter describes the application of multiplex immunoassay of hormones which are known to be present at different levels during aging and may therefore be precipitous in age-related diseases. As an example, we have analyzed serum from 12-week-old rats using multiplexes for the hormones insulin, leptin, growth hormone, corticosterone, and testosterone, which have been implicated in sarcopenia. The same technique can be used in the investigation of other sarcopenia biomarkers as well as in other disease cases involving both clinical and preclinical biomarker studies.

Changes and Risk Factors of Skeletal Muscle Mass and Strength in Patients with Type 2 Diabetes over 60 Years Old: A Cross-Sectional Study from China

OBJECTIVE

The accelerate loss of skeletal muscle mass, strength, and function, named sarcopenia, is a progressive and generalised skeletal muscle disorder, and it is always associated with increased outcomes including falls, frailty, and disability. Diabetes mellitus is associated with significant muscle and physical complications. We aimed at clarifying the changes and risk factors of skeletal muscle mass and strength in elderly with type 2 diabetes.

METHODS

The study consisted of patients with type 2 diabetes (n = 120) and an older general population (n = 126). The skeletal muscle mass and muscle strength, as well as the serum levels of chronic inflammation, oxidative stress, homocysteine, and insulin-like factor-1 were assessed, and the correlation and regression analysis were conducted to evaluate outcomes.

RESULTS

T2DM patients exhibited lower muscle strength compared with the non-T2DM subjects (P < 0.01). Among T2DM patients, serum IGF-1 levels were positively correlated with muscle strength (r = 0.255, P < 0.01) and muscle mass (r = 0.209, P < 0.05), levels of 8-OHdG were inversely correlated with muscle strength (r = -0.252, P < 0.01), and there was a negative association between HCY and muscle mass (r = -0.185, P < 0.05). Muscle mass and strength of patients with higher education level were significantly higher than those with lower education level (P < 0.05), in male patients, muscle mass and muscle strength were significantly lower in smokers (P < 0.01), and muscle mass was lower in chronic drinkers (P < 0.05).

CONCLUSIONS

These findings suggest that diabetic patients may be more susceptible to sarcopenia at an older age. And it also provides evidences that among elderly with diabetes mellitus, oxidative damage and HCY as well as IGF-1 are important predictors of age-dependent sarcopenia.

Prevalence of obesity and obesity-associated muscle wasting in patients on peritoneal dialysis

BACKGROUND AND AIMS

A progressive decrease in muscle mass until full-blown sarcopenia may occur in patients on peritoneal dialysis (PD) and worsen their life quality and expectancy. Here we investigate the prevalence of obesity and obesity-associated muscle wasting in PD patients.

PATIENTS AND METHODS

The study design was observational, cross sectional. Body composition was assessed with BIA and BIVA in 88 PD patients (53.4 ± 13.1 years; 67% male). Patients with obesity and/or with reduced muscle mass were identified using FMI and SM/BW cutoff values, respectively. Inflammatory status was assessed by measuring CRP and fibrinogen blood levels.

RESULTS

A total of 44.3% of the patients showed a reduced muscle mass (37.5% moderate and 6.8% severe). The prevalence of obesity was 6.1%, 81.8%, and 100% in patients with normal, moderately, and severely reduced muscle mass, respectively (p < 0.05). Of the total, 15.2% of the patients with normal muscle mass, 18.4% of those with moderately reduced muscle mass, and 66.7% of those with severely reduced muscle mass had diabetes. The prevalence of severe muscle mass loss was higher in those with diabetes than in those without diabetes (22.2% vs. 2.8%, p < 0.05). Patients with obesity-associated muscle wasting showed higher fibrinogen (613.9 ± 155.1 vs. 512.9 ± 159.5 mg/dL, p < 0.05) and CPR (1.4 ± 1.3 vs. 0.6 ± 0.8 mg/dL, p < 0.05) blood concentrations than those with normal body composition.

CONCLUSION

Obesity and diabetes were strongly associated with muscle mass loss in our PD patients. It remains to be established whether prevention of obesity with nutritional interventions can halt the occurrence of muscle mass loss in patients on PD.

Differentially methylated gene patterns between age-matched sarcopenic and non-sarcopenic women

BACKGROUND

Sarcopenia is characterized by progressive decreases in muscle mass, muscle strength, and muscle function with ageing. Although many studies have investigated the mechanisms of sarcopenia, its connection with epigenetic factors, such as DNA methylation, still remains poorly understood. The aim of this study was to explore sarcopenia-related DNA methylation differences in blood samples between age-matched sarcopenic and non-sarcopenic older women.

METHODS

A sarcopenic group (n = 24) was identified and selected from a set of 247 older Caucasian women (aged 65-80 years) based on cut-off points of skeletal muscle index at 6.75 kg/m² and grip strength at 26 kg (the lower quintile of grip strength in the set). A non-sarcopenic group (n = 24) was created with a similar age distribution as that of the sarcopenic group. DNA methylation patterns of whole blood samples from both groups were analysed using Infinium MethylationEPIC BeadChip arrays. Differentially methylated cytosin-phosphate-guanine sites (dmCpGs) were identified at a P value threshold of 0.01 by comparing methylation levels between the sarcopenic and non-sarcopenic groups at each CpG site. dmCpG-related genes were annotated based on Homo sapiens hg19 genome build. The functions of these genes were further examined by GO and KEGG pathway enrichment analysis.

RESULTS

The global methylation level of all analysed CpG sites (n = 788 074) showed no significant difference between the sarcopenic and non-sarcopenic groups (0.812), while the average methylation level of dmCpGs (n = 6258) was significantly lower in the sarcopenic group (0.004). The sarcopenic group had significantly higher methylation levels in TSS200 (the region from transcription start site to 200 nucleotides upstream of the site) and lower methylation levels in gene body and 3'UTR regions. In respect of CpG regions, CpG islands in promoters and some intragenic regions showed greater levels of methylation in the sarcopenic group. dmCpG-related KEGG pathways were mainly associated with muscle function, actin cytoskeleton regulation, and energy metabolism. Seven genes (HSPB1, PBX4, CNKSR3, ORMDL3, MIR10A, ZNF619, and CRADD) were found with the same methylation direction as previous studies of blood sample methylation during ageing. Fifty-four genes were shared with previous studies of resistance training.

CONCLUSIONS

Our results improve understanding of epigenetic mechanisms of sarcopenia by identifying sarcopenia-related DNA methylation differences in blood samples of older women. These methylation differences suggest underlying alterations of gene expression and pathway function, which can partially explain sarcopenia-related muscular changes.

Vitamin D in Relation to Incident Sarcopenia and Changes in Muscle Parameters Among Older Adults: The KORA-Age Study

Effects of low serum 25OHD on age-related changes in muscle mass and function remain unclear. Our aims were to explore associations of baseline 25OHD levels with prevalent and incident sarcopenia and changes in muscle parameters, and to examine the role of parathyroid hormone (PTH) therein. Cross-sectional (n = 975) and prospective analyses (n = 702) of older adults aged 65-93 years participating in the KORA-Age study. Sarcopenia was defined using the 2010 European Working Group on Sarcopenia in Older People (EWGSOP) criteria as low muscle mass combined with low grip strength or low physical performance. Associations with baseline 25OHD were examined in multiple regression analyses. Low vitamin D status was linked to increased odds of prevalent sarcopenia. Over three years, low baseline 25OHD < 25 vs. ≥ 50 nmol/L were associated with greater loss of muscle mass and increased time for the Timed Up and Go test. The risk for developing incident sarcopenia was not significantly elevated in individuals with low baseline 25OHD but when including death as combined outcome alongside incident sarcopenia, there was a strong positive association in multivariable analysis [OR (95% CI) 3.19 (1.54-6.57) for 25OHD < 25 vs. ≥ 50 nmol/L]. There was no evidence for a PTH-mediating effect. Low baseline 25OHD levels were associated with unfavorable changes in muscle mass and physical performance, but not with incident sarcopenia. Future randomized trials are needed to assess causality and to address the issue of competing risks such as mortality in older cohorts.

Circulating miR-203 derived from metastatic tissues promotes myopenia in colorectal cancer patients

BACKGROUND

Sarcopenia frequently occurs in metastatic cancer patients. Emerging evidence has revealed that various secretory products from metastatic tumours can influence host organs and promote sarcopenia in patients with malignancies. Furthermore, the biological functions of microRNAs in cell-to-cell communication by incorporating into neighbouring or distal cells, which have been gradually elucidated in various diseases, including sarcopenia, have been elucidated.

METHODS

We evaluated psoas muscle mass index (PMI) and intramuscular adipose tissue content (IMAC) using pre-operative computed tomography imaging in 183 colorectal cancer (CRC) patients. miR-203 expression levels in CRC tissues and pre-operative serum were evaluated using quantitative polymerase chain reaction. Functional analysis of miR-203 overexpression was investigated in human skeletal muscle cells (SkMCs), and cells were analysed for proliferation and apoptosis. Expressions of several putative miR-203 target genes (CASP3, CASP10, BIRC5, BMI1, BIRC2, and BIRC3) in SKMCs were validated.

RESULTS

A total of 183 patients (108 men and 75 women) were included. The median age of enrolled patients at diagnosis was 68.0 years (range 35-89 years). High IMAC status significantly correlated with female gender (P = 0.004) and older age (P = 0.0003); however, no other clinicopathological factors correlated with IMAC status in CRC patients. In contrast, decreased PMI significantly correlated with female gender (P = 0.006) and all well-established disease development factors, including advanced T stage (P = 0.035), presence of venous invasion (P = 0.034), lymphovascular invasion (P = 0.012), lymph node (P = 0.001), distant metastasis (P = 0.002), and advanced Union for International Cancer Control tumour-node-metastasis stage classification (P = 0.0004). Although both high IMAC status and low PMI status significantly correlated with poor overall survival (IMAC: P = 0.0002; PMI: P < 0.0001; log-rank test) and disease-free survival (IMAC: P = 0.0003; PMI: P = 0.0002; log-rank test), multivariate Cox's regression analysis revealed that low PMI was an independent prognostic factor for both overall survival (hazard ratio: 4.69, 95% confidence interval (CI): 2.19-10, P = 0.0001) and disease-free survival (hazard ratio: 2.33, 95% CI: 1.14-4.77, P = 0.021) in CRC patients. Serum miR-203 expression negatively correlated with pre-operative PMI level (P = 0.0001, ρ = -0.25), and multivariate logistic regression analysis revealed that elevated serum miR-203 was an independent risk factor for myopenia (low PMI) in CRC patients (odds ratio: 5.16, 95% CI: 1.8-14.8, P = 0.002). Overexpression of miR-203 inhibited cell proliferation and induced apoptosis via down-regulation of BIRC5 (survivin) expression in human SkMC line.

CONCLUSIONS

Assessment of serum miR-203 expression could be used for risk assessment of myopenia, and miR-203 might be a novel therapeutic target for inhibition of myopenia in CRC.

The novel myokine irisin: clinical implications and potential role as a biomarker for sarcopenia in postmenopausal women

PURPOSE

To clarify the association of circulating irisin with muscle, liver and bone, and to evaluate irisin as a biomarker for sarcopenia in postmenopausal women.

METHODS

Quadriceps cross-sectional area (QcCSA), bone mineral density (BMD), liver attenuation (measured in Hounsfield units (HU)) were assessed using quantitative computed tomography in 153 postmenopausal women, mean age of 72.20 ± 5.96 years. Muscle strength and physical performance were evaluated by handgrip test and short physical performance battery, respectively. Serum irisin was measured by an enzyme-linked immunosorbent assay kit. In addition, 147 young women were recruited as a reference group to define cut-off values for sarcopenia.

RESULTS

Circulating irisin was positively correlated with QcCSA/body weight (BW) and liver HU even after adjusting for multiple covariates, and the serum level was significantly lower in the sarcopenia group (QcCSA/BW<-2SD of the mean values for young women) than in the presarcopenia (-2SD≤QcCSA/BW<-1SD) or control groups (1SD≤QcCSA/BW<2SD). Logistic regression models showed that the relationship between circulating irisin and prevalence of sarcopenia remained significant after adjusting for confounding factors (per 1.0 ng/mL decrease of irisin, odds-ratio = 1.95, 95% confidence interval 1.33-2.87, p-value = 0.001).

CONCLUSIONS

In postmenopausal women, serum irisin may be used as a biomarker for sarcopenia, and we showed the potential for the development of irisin-based early screening and staging tool for sarcopenia.

High brain natriuretic peptide is associated with sarcopenia in patients with type 2 diabetes: a cross-sectional study of KAMOGAWA-DM cohort study

Association between heart failure and sarcopenia has been reported, however, the association between sarcopenia and brain natriuretic peptide (BNP) is unclear. Thus, we investigated the association between sarcopenia and BNP in type 2 diabetic patients without heart failure. In this cross-sectional study, skeletal muscle mass index (SMI, kg/m²) was calculated as appendicular muscle mass, measured by bioimpedance analyzer, by the square of the height. Sarcopenia was defined as having both handgrip strength of <26 kg for men and <18 kg for women, and SMI of <7.0 kg/m² for men and <5.7 kg/m² for women. To investigate the impact of BNP levels on the presence of sarcopenia, propensity-score matching analysis was used to remove the bias of confounding variables, including age, sex, duration of diabetes, body mass index, exercise, systolic blood pressure, smoking status, hemoglobin A1c, creatinine, energy and protein intake. The area under the curve (AUC) of BNP levels for the presence of sarcopenia was calculated by the receiver operating characteristic curve (ROC). Among 433 patients (236 men and 65.4 (11.1) years), 32 patients (7.4%) were diagnosed as sarcopenia. In the propensity-matched 58 patients, BNP levels (Δ10 pg/mL incremental) were associated with the presence of sarcopenia by logistic regression analysis, (odds ratio: 1.56, 95% confidence interval: 1.14-2.13, p = 0.002). The optimal cut-off point of BNP levels for sarcopenia is 27.3 pg/mL (AUC 0.777, 95%CI, 0.691-0.863, sensitivity = 0.813, specificity = 0.736, p < 0.001). In conclusion, BNP levels were associated with sarcopenia in type 2 diabetic patients without heart failure.

Plasma Transthyretin as A Biomarker of Sarcopenia in Elderly Subjects

Skeletal muscle (SM) mass, the chief component of the structural compartment belonging to lean body mass (LBM), undergoes sarcopenia with increasing age. Decreased SM in elderly persons is a naturally occurring process that may be accelerated by acute or chronic nutritional deficiencies and/or inflammatory disorders, declining processes associated with harmful complications. A recently published position paper by European experts has provided an overall survey on the definition and diagnosis of sarcopenia in elderly persons. The present review describes the additional contributory role played by the noninvasive transthyretin (TTR) micromethod. The body mass index (BMI) formula is currently used in clinical studies as a criterion of good health to detect, prevent, and follow up on the downward trend of muscle mass. The recent upsurge of sarcopenic obesity with its multiple subclasses has led to a confused stratification of SM and fat stores, prompting workers to eliminate BMI from screening programs. As a result, investigators are now focusing on indices of protein status that participate in SM growth, maturation, and catabolism that might serve to identify sarcopenia trajectories. Plasma TTR is clearly superior to all other hepatic biomarkers, showing the same evolutionary patterns as those displayed in health and disease by both visceral and structural LBM compartments. As a result, this TTR parameter maintains positive correlations with muscle mass downsizing in elderly persons. The liver synthesis of TTR is downregulated in protein-depleted states and suppressed in cytokine-induced inflammatory disorders. TTR integrates the centrally-mediated regulatory mechanisms governing the balance between protein accretion and protein breakdown, emerging as the ultimate indicator of LBM resources. This review proposes the adoption of a gray zone defined by cut-off values ranging from 200 mg/L to 100 mg/L between which TTR plasma values may fluctuate and predict either the best or the worst outcome. The best outcome occurs when appropriate dietary, medicinal and surgical decisions are undertaken, resuming TTR synthesis which manifests rising trends towards pre-stress levels. The worst occurs when all therapeutic means fail to succeed, leading inevitably to complete exhaustion of LBM and SM metabolic resources with an ensuing fatal outcome. Some patients may remain unresponsive in the middle of the gray area, combining steady clinical states with persistent stagnant TTR values. Using the serial measurement of plasma TTR values, these last patients should be treated with the most aggressive and appropriate therapeutic strategies to ensure the best outcome.

Bone and muscle specific circulating microRNAs in postmenopausal women based on osteoporosis and sarcopenia status

MicroRNAs (miRNAs) are short, non-coding RNA molecules that fine tune posttranscriptional protein expression. Aging is accompanied by progressive declines in muscle mass and strength, and in bone mineral density (BMD). Although miRNAs in pathology have been extensively studied, the role of circulating miRNAs (c-miRNAs) in osteoporosis and sarcopenia has to date not been well understood. The purpose of this study was to examine the difference in bone and muscle specific c-miRNAs in postmenopausal women based on their bone and muscle status, and to determine the associations between these specific c-miRNAs and muscle and bone variables. Seventy-five postmenopausal women aged 60 to 85 years old participated in this study. Body composition and BMD, functional performance tests (grip strength, gait speed, and countermovement jumps) were assessed. Levels of c-miRNAs (miR-1-3p, -21-5p, -23a-3p, -24-3p, -100-5p, -125b-5p, -133a-3p, -206) and bone turnover markers were analyzed. Statistically, there were no significant differences in specific c-miRNAs based on sarcopenia and osteoporosis status. However, fold changes of miR-21-5p (FC = 2.59) and -23a-3p (FC = 2.09) indicated upregulation and miR-125b-5p (FC = 0.46) indicated downregulation in the osteoporotic group compared to the non-osteoporotic group. The relative expression level of miR-125b-5p was significantly positively correlated with age (p < 0.05). The relative expression level of miR-21-5p was significantly negatively correlated with trochanter BMC (p < 0.05). Furthermore, the relative expression level of miR-23a-3p was significantly positively correlated with TRAP5b levels (p < 0.05). Although no statistical differences were found in target c-miRNAs based on muscle and bone status, our results indicate that there are biological differential expressions in some c-miRNAs between osteoporotic and non-osteoporotic individuals. Other circulating miRNAs need to be studied in the future.

Lack of Association Between Vitamin D and Hand Grip Strength in Asians: A Nationwide Population-Based Study

Despite the beneficial role and plausible mechanism of vitamin D on skeletal muscle in animal studies, its association in humans remains a controversial issue due to inconsistent clinical results, especially in older Asians. This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys, which enrolled 354 men aged ≥ 50 years and 328 postmenopausal women. Hand grip strength (HGS) was measured using a digital grip strength dynamometer. Low muscle strength was defined based on Korean-specific cut-off point of HGS. Serum 25-hydroxyvitamin D [25(OH)D] levels were 19.4 ± 6.7 and 17.1 ± 7.2 ng/mL in men and women, respectively. Among covariates including age, body mass index, lifestyle factors, and protein intake, age was inversely associated with HGS in both men and women, and protein intake (g/day) was positively associated with HGS only in men. However, the independent correlation between serum 25(OH)D and HGS was not observed, regardless of gender. When subjects were divided into three groups [deficient (25(OH)D < 20 ng/mL; 63.8%), insufficient (20 ≤ 25(OH)D < 30 ng/mL; 30.0%), or sufficient (25(OH)D ≥ 30 ng/mL; 6.2%)], there was no significant difference in HGS among these groups in both men and women. Consistently, serum 25(OH)D was not significantly different between subjects with and without low muscle strength, and there was no independent association of serum 25(OH)D with the risk of low muscle strength in both genders. These findings provide clinical evidence that protective role of vitamin D on human muscle metabolism may not be evident at least in older Asians.

The Association between Sarcopenia and Prealbumin Levels among Elderly Chinese Inpatients

OBJECTIVES

The goal of the present study was to assess the relationship between sarcopenia and prealbumin levels among hospitalized patients ages 60 and older.

DESIGN

Cross-sectional study.

SETTING

The geriatric wards in Guizhou Provincial People's Hospital, Guiyang. Guizhou, China.

MEASUREMENTS

Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) criteria, which consist of three components: low muscle mass, assessed based on an index of appendicular skeletal mass/height2 <7.0kg/m2 for men and <5.4kg/m2 for women; low muscle strength, defined as handgrip strength <26kg for men and <18kg for women; and low physical performance, defined as gait speed <0.8m/s. Using these criteria, sarcopenia was defined as presence of low muscle mass in addition to low muscle strength and/or low physical performance. Prealbumin levels and other variables were considered as being independent variables in an effort to evaluate any potential associations between these factors and sarcopenia status using non-adjusted and multivariate-adjusted regression models.

RESULTS

The overall prevalence of sarcopenia was 60.17%, affecting 65 (70.65%) men and 6 (23.08%) women in the present study. Age, body mass index (BMI), and prealbumin levels were each independently associated with sarcopenia (p<0.05). In a multivariate model, after adjusting for all potential covariates, prealbumin levels remained significantly associated with sarcopenia incidence, with an inflection point of 265.9mg/L. The effect sizes and the confidence intervals on the left and right sides of this inflection point were 0.94 (0.90 to 0.99) and 1.07 (0.93 to 1.23), respectively.

CONCLUSION

Among older Chinese inpatients in the present study, prealbumin levels were negatively correlated with sarcopenia incidence, when prealbumin levels were below 265.9mg/L.

Serum Myostatin and IGF-1 as Gender-Specific Biomarkers of Frailty and Low Muscle Mass in Community-Dwelling Older Adults

OBJECTIVES

(i) To investigate serum myostatin (absolute and normalized for total body lean mass (TBLM)) and IGF-1 as biomarkers of frailty and low relative appendicular skeletal muscle mass (RASM) in older adults, and; (ii) to examine gender differences in the association of serum myostatin and IGF-1 levels with frailty and low RASM.

DESIGN

Cross-sectional study.

SETTING

The "Longitudinal Assessment of Biomarkers for characterization of early Sarcopenia and predicting frailty and functional decline in community-dwelling Asian older adults Study" (GERI-LABS) study in Singapore.

PARTICIPANTS

200 subjects aged 50 years and older residing in the community.

MEASUREMENTS

Frailty was assessed using the modified Fried criteria. Low RASM was defined using cutoffs for height-adjusted appendicular skeletal muscle mass measured by dual-energy X-ray absorptiometry as recommended by the Asian Working Group for Sarcopenia. Comorbidities, cognitive and functional performance, physical activity and nutritional status were assessed. Blood samples collected included serum myostatin, insulin-like growth factor 1 (IGF-1) and markers of inflammation (total white cell count, CRP, IL-6 and TNFaR1). Subjects were classified into 4 groups: Frail/Prefrail with low RASM (Frail/Low RASM), Frail/Prefrail with normal RASM (Frail/Normal RASM), Robust with low RASM (Robust/Low RASM) and Robust with normal RASM (Robust/Normal RASM).

RESULTS

63 (32%) subjects were classified as Frail/Low RASM, 53 (27%) Frail/Normal RASM, 28 (14%) Robust/Low RASM and 56 (28%) Robust/Normal RASM respectively. Frail/Low RASM subjects were older and had lower BMI compared to Frail/Normal RASM and robust subjects. Mean (SE) normalized myostatin levels were higher in Frail/Low RASM compared to Frail/Normal RASM subjects (1.0 (0.04) versus 0.84 (0.05) ng/ml/kg, P=0.01). Median (IQR) IGF-1 level was lower amongst Frail/Low RASM subjects compared to Frail/Normal RASM subjects (102.3, (77.7, 102.5) vs 119.7 (82.7, 146.0) ng/ml, P=0.046). No differences in myostatin or IGF-1 were observed among robust individuals with or without low muscle mass. In adjusted multinomial logistic regression models with Robust/Normal RASM as the reference group, myostatin (P=0.05) and IGF-1 (P=0.043) were associated with Frail/Low RASM status in the whole cohort. When stratified by gender, myostatin was significantly associated with Frail/Low RASM status in men only (P=0.03). In women, serum IGF-1 was associated with Frail/Low RASM status (P=0.046), but not myostatin (P=0.53).

CONCLUSION

Serum myostatin, normalized for TBLM in men and IGF-1 in women are potential biomarkers for frail individuals with low RASM, and may identify a target group for intervention.

Is Iron Accumulation a Possible Risk Factor for Sarcopenia?

Sarcopenia has a high incidence among the elderly, with significant negative effects on the quality of life. The pathogenesis of sarcopenia is complex, and many factors are involved in its development and progression. Sarcopenia might be associated with iron accumulation given that (1) age-related iron accumulation was found in the skeletal muscle, (2) excess iron could cause skeletal muscle damage or atrophy, and (3) patients with sarcopenia showed higher levels of serum ferritin. Understanding the etiology and pathogenesis of sarcopenia would help to develop new treatment and preventive methods, thereby improving the quality of life of the elderly patients.

A Distinct Pattern of Circulating Amino Acids Characterizes Older Persons with Physical Frailty and Sarcopenia: Results from the BIOSPHERE Study

Physical frailty and sarcopenia (PF&S) are hallmarks of aging that share a common pathogenic background. Perturbations in protein/amino acid metabolism may play a role in the development of PF&S. In this initial report, 68 community-dwellers aged 70 years and older, 38 with PF&S and 30 non-sarcopenic, non-frail controls (nonPF&S), were enrolled as part as the "BIOmarkers associated with Sarcopenia and Physical frailty in EldeRly pErsons" (BIOSPHERE) study. A panel of 37 serum amino acids and derivatives was assayed by UPLC-MS. Partial Least Squares⁻Discriminant Analysis (PLS-DA) was used to characterize the amino acid profile of PF&S. The optimal complexity of the PLS-DA model was found to be three latent variables. The proportion of correct classification was 76.6 ± 3.9% (75.1 ± 4.6% for enrollees with PF&S; 78.5 ± 6.0% for nonPF&S). Older adults with PF&S were characterized by higher levels of asparagine, aspartic acid, citrulline, ethanolamine, glutamic acid, sarcosine, and taurine. The profile of nonPF&S participants was defined by higher concentrations of α-aminobutyric acid and methionine. Distinct profiles of circulating amino acids and derivatives characterize older people with PF&S. The dissection of these patterns may provide novel insights into the role played by protein/amino acid perturbations in the disabling cascade and possible new targets for interventions.

Sarcopenic obesity associated with high-sensitivity C-reactive protein in age and sex comparison: a two-center study in South Korea

OBJECTIVES

To evaluate the association between high-sensitivity C-reactive protein (hs-CRP) and sarcopenic obesity, and to determine age or sex differences underlying the relationship between hs-CRP and sarcopenic obesity.

DESIGN

Observational study.

PARTICIPANTS

The study included 237 838 participants whose body composition and hs-CRP were analysed at the two health promotion centres in South Korea. Participants were divided into four groups based on body composition: normal, obesity only, sarcopenia only and sarcopenic obesity.

PRIMARY MEASURES

The levels of hs-CRP and proportion of participants with high (≥1.0 mg/L) hs-CRP. Sarcopenic obesity was defined as subjects fulfilling the criteria for sarcopenia (below 2 SD of mean of Skeletal Muscle Mass Index for young adults) and obesity (waist circumference ≥90 cm for men and ≥85 cm for women).

RESULTS

The level of hs-CRP was highest in the sarcopenic obesity group. Following adjustment for various confounders including age, sex, comorbidities, metabolic, health-related behaviour and demographic factors, the adjusted ORs (95% CI) for subjects with high hs-CRP associated with obesity, sarcopenia and sarcopenic obesity compared with normal group (reference) were 1.17 (1.05 to 1.31), 2.23 (1.21 to 4.07) and 3.23 (2.71 to 3.83), respectively. In age subgroup analyses, multivariate logistic regression analysis revealed that the association of high hs-CRP with sarcopenic obesity was stronger in younger (<60 years) participants than in older (≥60 years) participants (p for interaction <0.001). In subgroup analyses for sex, the association of high hs-CRP with sarcopenic obesity was higher in female participants than in males (p for interaction <0.001).

CONCLUSIONS

This study demonstrated that high level of hs-CRP was independently associated with sarcopenic obesity in Korean population. We found for the first time that there was a strong association between increased hs-CRP and sarcopenic obesity in female and younger (<60 years) subjects.

The relationship between serum IGF-1, handgrip strength, physical performance and falls in elderly men and women

OBJECTIVE

Human aging is accompanied by a decrease in growth hormone secretion and serum insulin-like growth factor (IGF)-1 levels. Also, loss of muscle mass and strength and impairment of physical performance, ending in a state of frailty, are seen in elderly. We aimed to investigate whether handgrip strength, physical performance and recurrent falls are related to serum IGF-1 levels in community-dwelling elderly.

DESIGN

Observational cohort study (cross-sectional and prospective).

METHODS

We studied the association between IGF-1 and handgrip strength, physical performance and falls in participants of the Longitudinal Aging Study Amsterdam. A total of 1292 participants were included (633 men, 659 women). Serum IGF-1 levels were divided into quartiles (IGF-1-Q1 to IGF-1-Q4). Data on falls were collected prospectively for a period of 3 years. All analyses were stratified for age and physical activity and adjusted for relevant confounders.

RESULTS

Men with a low physical activity score in IGF-1-Q1 and IGF-1-Q2 of the younger age group had a lower handgrip strength compared to IGF-1-Q4. In younger more active males in IGF-1-Q2 physical performance was worse. Recurrent fallers were less prevalent in older, low active males with low IGF-1 levels. In females, recurrent fallers were more prevalent in older, more active females in IGF-1-Q2. IGF-1 quartile may predict changes in handgrip strength and physical performance in men and women.

CONCLUSIONS

Our results indicate that lower IGF-1 levels are associated with lower handgrip strength and worse physical performance, but less recurrent fallers especially in men. Associations were often more robust in IGF-1-Q2. Future studies on this topic are desirable.

Decreased the creatinine to cystatin C ratio is a surrogate marker of sarcopenia in patients with type 2 diabetes

AIMS

Sarcopenia has recently been shown to affect quality of life and mortality in patients with diabetes. However, early detection requires an expensive equipment. We hypothesized that the ratio of the creatinine/cystatin (Cre/CysC) could be used as a marker for sarcopenia.

METHODS

We investigated the association between the Cre/CysC ratio and sarcopenia in a cross-sectional study of patients with type 2 diabetes. Skeletal muscle mass (SMM) was estimated by bioelectrical impedance. The skeletal muscle index (SMI) was defined as the appendicular SMM divided by the square of the height. Sarcopenia was defined with SMI and a grip strength.

RESULTS

We identified 285 patients with type 2 diabetes, of whom 25 (8.8%) had sarcopenia. The Cre/CysC ratio was associated with an increased risk of sarcopenia [odds ratio per 0.01 increment, 1.05; 95% confidence interval (CI), 1.01-1.09] after adjusting for covariates. Receiver operating characteristic curve analysis indicated that the optimal the Cre/CysC ratio cut-off point for identifying sarcopenia was 0.9, with an area under the curve, sensitivity, and specificity of 0.683 (95% CI, 0.573-0.793), 0.80, and 0.48, respectively.

CONCLUSIONS

We recommend the Cre/CysC ratio as a practical screening marker for sarcopenia in patients with type 2 diabetes.

Oxidative stress is increased in sarcopenia and associated with cardiovascular disease risk in sarcopenic obesity

OBJECTIVES

To define whether circulating markers of oxidative stress correlate with sarcopenia in terms of glutathione balance and oxidative protein damage, and whether these biomarkers are associated with risk of cardiovascular disease (CVD).

STUDY DESIGN

Population-based cross-sectional study. 115 out of 347 elderly subjects were classified as non-sarcopenic non-obese (NS-NO), sarcopenic non-obese (S-NO), non-sarcopenic obese (NS-O), and sarcopenic obese (S-O).

MAIN OUTCOME MEASUREMENTS

Sarcopenia was defined as a relative skeletal muscle mass index (RASM) <7.25kg/m² for men or <5.67kg/m² for women, while obesity was diagnosed in those presenting with% fat >27 for men or >38 for women. The CVD risk was estimated by the carotid intima-media thickness (IMT) and the Framingham score. Blood reduced glutathione (GSH), oxidized glutathione (GSSG), plasma malondialdehyde-(MDA) and 4-hydroxy-2,3-nonenal-(HNE) protein adducts were analyzed.

RESULTS

Significantly greater blood GSSG/GSH ratio and plasma MDA/HNE protein adducts were observed in sarcopenic than in non-sarcopenic patients. A logistic regression model showed a close relationship between serum HNE and MDA adducts and sarcopenia (OR=1.133, 95% CI 1.057-1.215, and OR=1.592, 95% CI 1.015-1.991, respectively). Linear and logistic regression analysis evidenced strong associations between the IMT or the Framingham CVD risk category and blood GSSG/GSH or serum HNE protein adducts in the S-O group.

CONCLUSION

Circulating markers of oxidative stress are increased in sarcopenia and related to CVD risk in sarcopenic obesity, suggesting that redox balance analysis would be a useful part of a multidimensional evaluation in aging. Further research is encouraged to support interventional strategies to correct redox imbalance, which might contribute to the prevention or at least limitation of sarcopenia and its co-morbidities.

Nutrition in the Very Old

The population of older adults aged 85 years and over (the very old) is growing rapidly in many societies because of increases in life expectancy and reduced mortality at older ages. In 2016, 27.3 million very old adults were living in the European Union, and in the UK, 2.4% of the population (1.6 million) were aged 85 and over. Very old age is associated with increased risks of malnutrition, multimorbidity, and disability. Diet (nutrition) is a modifiable risk factor for multiple age-related conditions, including sarcopenia and functional decline. Dietary characteristics and nutrient intakes of the very old have been investigated in several European studies of ageing to better understand their nutritional requirements, which may differ from those in the young-old. However, there is a major gap in regard to evidence for the role of dietary patterns, protein, vitamin D and other nutrients for the maintenance of physical and cognitive functioning in later life. The Newcastle 85+ Study, UK and the Life and Living in Advanced Age, New Zealand are unique studies involving single birth cohorts which aim to assess health trajectories in very old adults and their biological, social and environmental influences, including nutrition. In this review, we have updated the latest findings in nutritional epidemiology with results from these studies, concentrating on the diet-physical functioning relationship.

Metabolic phenotyping using kinetic measurements in young and older healthy adults

BACKGROUND

The aging process is often associated with the presence of sarcopenia. Although changes in the plasma concentration of several amino acids have been observed in older adults, it remains unclear whether these changes are related to disturbances in whole body production and/or interconversions.

METHODS

We studied 10 healthy young (~22.7y) and 17 older adults (~64.8y) by administering a mixture of stable amino acid tracers in a pulse and in a primed constant infusion. We calculated whole body production (WBP) and metabolite to metabolite interconversions. In addition, we measured body composition, muscle function, and provided questionnaires to assess daily dietary intake, physical activity, mood (anxiety, depression) and markers of cognitive function. Plasma enrichments and metabolite concentrations were measured by GC- and LC-MS/MS and statistics were performed by student t-test.

RESULTS

Older adults had a 11% higher body mass index (p=0.04) and 27% reduced peak leg extension force (p=0.02) than the younger group, but comparable values for muscle mass, mood and cognitive function. Although small differences in several plasma amino acid concentrations were observed, we found older adults had about 40% higher values of WBP for glutamine (221±27 vs. 305±21μmol/kgffm/h, p=0.03) and tau-methylhistidine (0.15±0.01 vs. 0.21±0.02μmol/kgffm/h, p=0.04), 26% lower WBP value for arginine (59±4 vs. 44±4μmol/kgffm/h, p=0.02) and a reduction in WBP (50%; 1.23±0.15 vs. 0.69±0.06μmol/kgffm/h, p=0.001) and concentration (25%; 3.5±0.3μmol/l vs. 2.6±0.2μmol/l, p=0.01) for β-Hydroxy β-Methylbutyrate. No differences were observed in protein catabolism. Clearance of arginine was decreased (27%, p=0.03) and clearance of glutamine (58%, p=0.01), leucine (67%, p=0.001) and KIC (76%, p=0.004) were increased in older adults.

CONCLUSIONS

Specific differences exist between young and older adults in amino acid metabolism.