Sarcopenia and Chronic Complications of Type 2 Diabetes Mellitus

Prevalence and factors associated with sarcopenia among Brazilian older adults: An exploratory network analysis

OBJECTIVES

This study aimed to verify the prevalence of sarcopenia and its associations with sociodemographic, clinical and psychological factors in community-dwelling older adults.

STUDY DESIGN

A randomized cross-sectional study was extracted from a probabilistic cluster conducted on individuals aged 65 years or older residing in the community.

METHODS

Sarcopenia was defined according to the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2). Body composition was assessed using dual-energy X-ray absorptiometry (DXA). Associations were analyzed using networks based on mixed graphical models. Predictability indices of the estimated networks were assessed using the proportion of explained variance for numerical variables and the proportion of correct classification for categorical variables.

RESULTS

The study included 278 participants, with a majority being female (61 %). The prevalence of sarcopenia was 39.57 %. Among those with sarcopenia, 67 % were women and 33 % were men. In the network model, age, race, education, family income, bone mass, depression, cardiovascular disease, diabetes, total cholesterol levels and rheumatism were associated with sarcopenia. The covariates demonstrated a high accuracy (62.9 %) in predicting sarcopenia categories.

CONCLUSION

The prevalence of sarcopenia was high, especially in women. In addition, network analysis proved useful in visualizing complex relationships between sociodemographic and clinical factors with sarcopenia. The results suggest early screening of sarcopenia for appropriate treatment of this common geriatric syndrome in older adults in Brazil.

Diabetes-induced muscle wasting: molecular mechanisms and promising therapeutic targets

Diabetes has become a serious public health crisis, presenting significant challenges to individuals worldwide. As the largest organ in the human body, skeletal muscle is a significant target of this chronic disease, yet muscle wasting as a complication of diabetes is still not fully understood and effective treatment methods have yet to be developed. Here, we discuss the targets involved in inducing muscle wasting under diabetic conditions, both validated targets and emerging targets. Diabetes-induced skeletal muscle wasting is known to involve changes in various signaling molecules and pathways, such as protein degradation pathways, protein synthesis pathways, mitochondrial function, and oxidative stress inflammation. Recent studies have shown that some of these present potential as promising therapeutic targets, including the neuregulin 1/epidermal growth factor receptor family, advanced glycation end-products, irisin, ferroptosis, growth differentiation factor 15 and more. This study's investigation and discussion of such pathways and their potential applications provides a theoretical basis for the development of clinical treatments for diabetes-induced muscle wasting and a foundation for continued focus on this disease.

Systemic impacts of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) on heart, muscle, and kidney related diseases

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disorder worldwide, with an estimated global prevalence of more than 31%. Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is a progressive form of MASLD characterized by hepatic steatosis, inflammation, and fibrosis. This review aims to provide a comprehensive analysis of the extrahepatic manifestations of MASH, focusing on chronic diseases related to the cardiovascular, muscular, and renal systems. A systematic review of published studies and literature was conducted to summarize the findings related to the systemic impacts of MASLD and MASH. The review focused on the association of MASLD and MASH with metabolic comorbidities, cardiovascular mortality, sarcopenia, and chronic kidney disease. Mechanistic insights into the concept of lipotoxic inflammatory "spill over" from the MASH-affected liver were also explored. MASLD and MASH are highly associated (50%-80%) with other metabolic comorbidities such as impaired insulin response, type 2 diabetes, dyslipidemia, hypertriglyceridemia, and hypertension. Furthermore, more than 90% of obese patients with type 2 diabetes have MASH. Data suggest that in middle-aged individuals (especially those aged 45-54), MASLD is an independent risk factor for cardiovascular mortality, sarcopenia, and chronic kidney disease. The concept of lipotoxic inflammatory "spill over" from the MASH-affected liver plays a crucial role in mediating the systemic pathological effects observed. Understanding the multifaceted impact of MASH on the heart, muscle, and kidney is crucial for early detection and risk stratification. This knowledge is also timely for implementing comprehensive disease management strategies addressing multi-organ involvement in MASH pathogenesis.

Identifying the potential therapeutic effects of miR‑6516 on muscle disuse atrophy

Muscle atrophy is a debilitating condition with various causes; while aging is one of these causes, reduced engagement in routine muscle‑strengthening activities also markedly contributes to muscle loss. Although extensive research has been conducted on microRNAs (miRNAs/miRs) and their associations with muscle atrophy, the roles played by miRNA precursors remain underexplored. The present study detected the upregulation of the miR‑206 precursor in cell‑free (cf)RNA from the plasma of patients at risk of sarcopenia, and in cfRNAs from the muscles of mice subjected to muscle atrophy. Additionally, a decline in the levels of the miR‑6516 precursor was observed in mice with muscle atrophy. The administration of mimic‑miR‑6516 to mice immobilized due to injury inhibited muscle atrophy by targeting and inhibiting cyclin‑dependent kinase inhibitor 1b (Cdkn1b). Based on these results, the miR‑206 precursor appears to be a potential biomarker of muscle atrophy, whereas miR‑6516 shows promise as a therapeutic target to alleviate muscle deterioration in patients with muscle disuse and atrophy.

Unraveling the enigma of sarcopenia and sarcopenic obesity in Indian adults with type 2 diabetes - a comparative cross-sectional study

BACKGROUND

Sarcopenia and sarcopenic obesity are growing concerns associated with increasing diabetes incidence, but data from Indian diabetic cohorts are limited. This study examined the prevalence and clinical factors associated with sarcopenia and sarcopenic obesity.

METHODS

In this cross-sectional study, 750 participants aged 35-70 years were recruited by systematic stratification and a fixed quota sampling technique from medical camps and categorized into diabetic (n = 250), nondiabetic (n = 250), and obese nondiabetic (n = 250) groups. The assessments included questionnaires, muscle mass estimation by bioimpedance analysis, and blood tests. Sarcopenia was defined using the Asian Working Group consensus, and sarcopenic obesity was defined as sarcopenia with a BMI ≥ 25 kg/m2. Logistic regression was used to analyze risk factors.

RESULTS

Sarcopenia affected 60% of diabetic patients, 28% of nondiabetic patients, and 38% of nonobese nondiabetic patients (p < 0.001). The prevalence of sarcopenic obesity was 40%, 11%, and 30%, respectively (p < 0.001). Diabetes was associated with 2.3-fold greater odds (95% CI 1.1-4.7) of sarcopenia and 2.4-fold greater odds (1.1-5.0) of sarcopenic obesity after adjustment. A duration greater than 10 years, uncontrolled diabetes, age greater than 65 years, low physical activity, hypertension, and dyslipidemia also independently increased the odds.

CONCLUSION

Indian adults with type 2 diabetes have a high burden of sarcopenia and sarcopenic obesity. Early optimization of diabetes care and lifestyle changes are vital for preserving muscle health.

Impaired skeletal muscle regeneration in diabetes: From cellular and molecular mechanisms to novel treatments

Diabetes represents a major public health concern with a considerable impact on human life and healthcare expenditures. It is now well established that diabetes is characterized by a severe skeletal muscle pathology that limits functional capacity and quality of life. Increasing evidence indicates that diabetes is also one of the most prevalent disorders characterized by impaired skeletal muscle regeneration, yet underlying mechanisms and therapeutic treatments remain poorly established. In this review, we describe the cellular and molecular alterations currently known to occur during skeletal muscle regeneration in people with diabetes and animal models of diabetes, including its associated comorbidities, e.g., obesity, hyperinsulinemia, and insulin resistance. We describe the role of myogenic and non-myogenic cell types on muscle regeneration in conditions with or without diabetes. Therapies for skeletal muscle regeneration and gaps in our knowledge are also discussed, while proposing future directions for the field.

Breast arterial calcification is associated with sarcopenia in peri- and post-menopausal women

PURPOSE

Breast arterial calcification (BAC) refers to medial calcium deposition in breast arteries and is detectable via mammography. Sarcopenia, which is characterised by low skeletal muscle mass and quality, is associated with several serious clinical conditions, increased morbidity, and mortality. Both BAC and sarcopenia share common pathologic pathways, including ageing, diabetes, and chronic kidney disease. Therefore, this study evaluated the relationship between BAC and sarcopenia as a potential indicator of sarcopenia.

METHODS

This study involved women aged >40. BAC was evaluated using digital mammography and was defined as vascular calcification. Sarcopenia was assessed using abdominal computed tomography. The cross-sectional skeletal mass area was measured at the third lumbar vertebra level. The skeletal mass index was obtained by dividing the skeletal mass area by height in square meters(m2). Sarcopenia was defined as a skeletal mass index of ≤38.5 cm2/m2. A multivariable model was used to evaluate the relationship between BAC and sarcopenia.

RESULTS

The study involved 240 participants. Of these, 36 (15 %) were patients with BAC and 204 (85 %) were without BAC. Sarcopenia was significantly higher among the patients with BAC than in those without BAC (72.2 % vs 17.2 %, P < 0.001). The multivariable model revealed that BAC and age were independently associated with sarcopenia (odds ratio[OR]: 7.719, 95 % confidence interval[CI]: 3.201-18.614, and P < 0.001 for BAC and OR: 1.039, 95 % CI: 1.007-1.073, P = 0.01 for age).

CONCLUSION

BAC is independently associated with sarcopenia. BAC might be used as an indicator of sarcopenia on screening mammography.

The Difference Between Cystatin C- and Creatinine-Based Estimated Glomerular Filtration Rate and Risk of Diabetic Microvascular Complications Among Adults With Diabetes: A Population-Based Cohort Study

OBJECTIVE

The impact of the difference between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff) on diabetic microvascular complications (DMCs) remains unknown. We investigated the associations of eGFRdiff with overall DMCs and subtypes, including diabetic retinopathy (DR), diabetic kidney disease (DKD), and diabetic neuropathy (DN).

RESEARCH DESIGN AND METHODS

This prospective cohort study included 25,825 participants with diabetes free of DMCs at baseline (2006 to 2010) from the UK Biobank. eGFRdiff was calculated using both absolute difference (eGFRabdiff) and the ratio (eGFRrediff) between cystatin C- and creatinine-based calculations. Incidence of DMCs was ascertained using electronic health records. Cox proportional hazards regression models were used to evaluate the associations of eGFRdiff with overall DMCs and subtypes.

RESULTS

During a median follow-up of 13.6 years, DMCs developed in 5,753 participants, including 2,752 cases of DR, 3,203 of DKD, and 1,149 of DN. Each SD decrease of eGFRabdiff was associated with a 28% higher risk of overall DMCs, 14% higher risk of DR, 56% higher risk of DKD, and 29% higher risk of DN. For each 10% decrease in eGFRrediff, the corresponding hazard ratios (95% CIs) were 1.16 (1.14, 1.18) for overall DMCs, 1.08 (1.05, 1.11) for DR, 1.29 (1.26, 1.33) for DKD, and 1.17 (1.12, 1.22) for DN. The magnitude of associations was not materially altered in any of the sensitivity analyses.

CONCLUSIONS

Large eGFRdiff was independently associated with risk of DMCs and its subtypes. Our findings suggested monitoring eGFRdiff in the diabetes population has potential benefit for identification of high-risk patients.

Impact of sarcopenic obesity on heart failure in people with type 2 diabetes and the role of metabolism and inflammation: A prospective cohort study

AIMS

We aimed to prospectively evaluate the association of sarcopenic obesity (SO) with the incidence risk of heart failure (HF), and the mediating role of metabolomics and inflammation in people with type 2 diabetes (T2D).

METHODS

22,496 participants with T2D from the UK Biobank were included. SO was defined as the combination of obesity (body mass index ≥30 kg/m2) and sarcopenia (grip strength <27 kg in male or <16 kg in female). The incident HF was identified through linked hospital records. Cox proportional hazard regression models were used to estimate the associations. Mediation analysis was conducted to evaluate the mediating effect of the "metabolomic risk score" of HF, which was derived from 168 plasma metabolites through LASSO regression, and five inflammatory markers (e.g., C-reactive protein [CRP] level) on the aforementioned associations.

RESULTS

1946 (8.7 %) participants developed HF during a median follow-up of 12.0 years. Compared to participants with neither obesity nor sarcopenia, those with obesity & non-sarcopenia (hazard ratio [HR]: 1.80, 95 % confidence interval [CI]: 1.62, 2.00), sarcopenia & non-obesity (HR: 1.90, 95 % CI: 1.56, 2.31) and SO (HR: 2.29, 95 % CI: 1.92, 2.73) showed a higher risk of HF. The metabolomic risk score (20.0 %) and CRP (20.4 %) meditated this association.

CONCLUSIONS

SO was associated with an increased risk of HF in people with T2D and metabolomics and inflammation partially mediated this association. Our findings suggest the importance of managing obesity and muscle strength simultaneously in preventing HF among people with T2D and shed light on the underlying mechanisms.

A Case of Acromegaly With Progressed Diabetic Retinopathy and Sarcopenia Diagnosed Following the Onset of Severe Hypoglycemia

Acromegaly is a rare disorder characterized by excessive production of growth hormone (GH) from a pituitary tumor, typically leading to elevated glucose levels due to increased insulin resistance; hypoglycemia is rare. However, the long-term effect of excess GH on the peripheral organs is still unclear. Here we present a 69-year-old man evaluated for the cause of a hypoglycemic episode. He was underweight (body mass index: 17.3 kg/m2) with sarcopenia, which potentially contributed to his hypoglycemia. Notably, he exhibited progressed proliferative diabetic retinopathy compared to other microvascular complications, leading to further endocrinological investigation. As a result, he was diagnosed with acromegaly showing elevated GH and insulin-like growth factor-1 (IGF-1) with a pituitary tumor. Opting against transsphenoidal surgery (TSS), the patient was treated with a somatostatin analog (SSA), achieving normalized IGF-1 levels with a monthly 120 mg lanreotide injection. In this case, acromegaly could lead to sarcopenia from GH-derived gluconeogenesis in the peripheral organs such as the reduction of muscle leading to reduced glucose reserves. Acromegaly in the elderly may present atypicality. Clinicians should be vigilant for unique manifestations such as advanced diabetic retinopathy, even in elderly patients with hypoglycemia.

Diabetes Mellitus Should Be Considered While Analysing Sarcopenia-Related Biomarkers

Sarcopenia is a chronic, progressive skeletal muscle disease characterised by low muscle strength and quantity or quality, leading to low physical performance. Patients with type 2 diabetes mellitus (T2DM) are more at risk of sarcopenia than euglycemic individuals. Because of several shared pathways between the two diseases, sarcopenia is also a risk factor for developing T2DM in older patients. Various biomarkers are under investigation as potentially valuable for sarcopenia diagnosis and treatment monitoring. Biomarkers related to sarcopenia can be divided into markers evaluating musculoskeletal status (biomarkers specific to muscle mass, markers of the neuromuscular junction, or myokines) and markers assuming causal factors (adipokines, hormones, and inflammatory markers). This paper reviews the current knowledge about how diabetes and T2DM complications affect potential sarcopenia biomarker concentrations. This review includes markers recently proposed by the expert group of the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) as those that may currently be useful in phase II and III clinical trials of sarcopenia: myostatin (MSTN); follistatin (FST); irisin; brain-derived neurotrophic factor (BDNF); procollagen type III N-terminal peptide (PIIINP; P3NP); sarcopenia index (serum creatinine to serum cystatin C ratio); adiponectin; leptin; insulin-like growth factor-1 (IGF-1); dehydroepiandrosterone sulphate (DHEAS); C-reactive protein (CRP); interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). A better understanding of factors influencing these biomarkers' levels, including diabetes and diabetic complications, may lead to designing future studies and implementing results in clinical practice.

Concordance between muscle mass assessed by bioelectrical impedance analysis and by muscle ultrasound: a cross-sectional study in a cohort of patients on chronic hemodialysis

BACKGROUND

Sarcopenia is a common problem in hemodialysis (HD) patients, and it is diagnosed by low muscle mass, strength and/or low physical performance. Muscle ultrasound (US) is a non-invasive portable tool that might be used for assessment of muscle mass. The aim of the current study was to investigate the concordance between muscle US and bioelectrical impedance analysis (BIA) in diagnosis of sarcopenia in HD patients.

METHODS

This cross-sectional study included 41 HD patients. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People (EWGSOP). The skeletal mass index was measured by BIA and the muscle strength was measured by handgrip strength. Muscle US was used to measure cross-sectional area (CSA) and thickness of quadriceps and biceps muscles.

RESULTS

The current study included 41 patients on HD (25 males), with a mean (SD) age of 44.18 (13.11) years and a median HD duration of 48 months. Sarcopenia was diagnosed in 58.5% of the patients. Patients with sarcopenia had significantly lower quadriceps muscle CSA than those without sarcopenia. The optimal cut-offs of quadriceps muscle CSA for both males and females for the diagnosis of sarcopenia were 2.96 and 2.92 cm2, respectively.

CONCLUSION

Sarcopenia is prevalent among Egyptian HD patients. US on quadriceps muscle CSA could be used for diagnosis of sarcopenia in these patients.

Celecoxib ameliorates diabetic sarcopenia by inhibiting inflammation, stress response, mitochondrial dysfunction, and subsequent activation of the protein degradation systems

Aim: Diabetic sarcopenia leads to disability and seriously affects the quality of life. Currently, there are no effective therapeutic strategies for diabetic sarcopenia. Our previous studies have shown that inflammation plays a critical role in skeletal muscle atrophy. Interestingly, the connection between chronic inflammation and diabetic complications has been revealed. However, the effects of non-steroidal anti-inflammatory drug celecoxib on diabetic sarcopenia remains unclear. Materials and Methods: The streptozotocin (streptozotocin)-induced diabetic sarcopenia model was established. Rotarod test and grip strength test were used to assess skeletal muscle function. Hematoxylin and eosin and immunofluorescence staining were performed to evaluate inflammatory infiltration and the morphology of motor endplates in skeletal muscles. Succinate dehydrogenase (SDH) staining was used to determine the number of succinate dehydrogenase-positive muscle fibers. Dihydroethidium staining was performed to assess the levels of reactive oxygen species (ROS). Western blot was used to measure the levels of proteins involved in inflammation, oxidative stress, endoplasmic reticulum stress, ubiquitination, and autophagic-lysosomal pathway. Transmission electron microscopy was used to evaluate mitophagy. Results: Celecoxib significantly ameliorated skeletal muscle atrophy, improving skeletal muscle function and preserving motor endplates in diabetic mice. Celecoxib also decreased infiltration of inflammatory cell, reduced the levels of IL-6 and TNF-α, and suppressed the activation of NF-κB, Stat3, and NLRP3 inflammasome pathways in diabetic skeletal muscles. Celecoxib decreased reactive oxygen species levels, downregulated the levels of Nox2 and Nox4, upregulated the levels of GPX1 and Nrf2, and further suppressed endoplasmic reticulum stress by inhibiting the activation of the Perk-EIF-2α-ATF4-Chop in diabetic skeletal muscles. Celecoxib also inhibited the levels of Foxo3a, Fbx32 and MuRF1 in the ubiquitin-proteasome system, as well as the levels of BNIP3, Beclin1, ATG7, and LC3Ⅱ in the autophagic-lysosomal system, and celecoxib protected mitochondria and promoted mitochondrial biogenesis by elevating the levels of SIRT1 and PGC1-α, increased the number of SDH-positive fibers in diabetic skeletal muscles. Conclusion: Celecoxib improved diabetic sarcopenia by inhibiting inflammation, oxidative stress, endoplasmic reticulum stress, and protecting mitochondria, and subsequently suppressing proteolytic systems. Our study provides evidences for the molecular mechanism and treatment of diabetic sarcopenia, and broaden the way for the new use of celecoxib in diabetic sarcopenia.

The Vicious Cycle of Type 2 Diabetes Mellitus and Skeletal Muscle Atrophy: Clinical, Biochemical, and Nutritional Bases

Today, type 2 diabetes mellitus (T2DM) and skeletal muscle atrophy (SMA) have become increasingly common occurrences. Whether the onset of T2DM increases the risk of SMA or vice versa has long been under investigation. Both conditions are associated with negative changes in skeletal muscle health, which can, in turn, lead to impaired physical function, a lowered quality of life, and an increased risk of mortality. Poor nutrition can exacerbate both T2DM and SMA. T2DM and SMA are linked by a vicious cycle of events that reinforce and worsen each other. Muscle insulin resistance appears to be the pathophysiological link between T2DM and SMA. To explore this association, our review (i) compiles evidence on the clinical association between T2DM and SMA, (ii) reviews mechanisms underlying biochemical changes in the muscles of people with or at risk of T2DM and SMA, and (iii) examines how nutritional therapy and increased physical activity as muscle-targeted treatments benefit this population. Based on the evidence, we conclude that effective treatment of patients with T2DM-SMA depends on the restoration and maintenance of muscle mass. We thus propose that regular intake of key functional nutrients, along with guidance for physical activity, can help maintain euglycemia and improve muscle status in all patients with T2DM and SMA.

The Effects of Sodium-Glucose Cotransporter 2 Inhibitors on Body Composition in Type 2 Diabetes Mellitus: A Narrative Review

Body composition is related to cardiometabolic disorders and is a major driver of the growing incidence of type 2 diabetes mellitus (T2DM). Altered fat distribution and decreased muscle mass are related to dysglycemia and impose adverse health-related outcomes in people with T2DM. Hence, improving body composition and maintaining muscle mass is crucial in T2DM. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are novel glucose-lowering medications gaining popularity because of their cardiorenal-protective effects and weight-lowering characteristics. However, reports on myopathy secondary to SGLT2 inhibitor treatment raised a safety concern. The importance of maintaining muscle mass in people with T2DM necessitates further investigation to explore the impact of novel medications on body composition. In this review, we discussed current evidence on the impact of SGLT2 inhibitors on body composition in people with T2DM.

A Narrative Literature Review on the Role of Exercise Training in Managing Type 1 and Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia associated with impaired carbohydrate, lipid, and protein metabolism, with concomitant absence of insulin secretion or reduced sensitivity to its metabolic effects. Patients with diabetes mellitus have a 30% more risk of developing heart failure and cardiovascular disease compared to healthy people. Heart and cardiovascular problems are the first cause of death worldwide and the main complications which lead to high healthcare costs. Such complications can be delayed or avoided by taking prescribed medications in conjunction with a healthy lifestyle (i.e., diet and physical activity). The American College of Sports Medicine and the American Diabetes Association recommend that diabetic people reduce total sedentary time by incorporating physical activity into their weekly routine. This narrative literature review aims to summarize and present the main guidelines, pre-exercise cardiovascular screening recommendations, and considerations for patients with diabetes and comorbidities who are planning to participate in physical activity programs.

Sarcopenia in a type 2 diabetic state: Reviewing literature on the pathological consequences of oxidative stress and inflammation beyond the neutralizing effect of intracellular antioxidants

Sarcopenia remains one of the major pathological features of type 2 diabetes (T2D), especially in older individuals. This condition describes gradual loss of muscle mass, strength, and function that reduces the overall vitality and fitness, leading to increased hospitalizations and even fatalities to those affected. Preclinical evidence indicates that dysregulated mitochondrial dynamics, together with impaired activity of the NADPH oxidase system, are the major sources of oxidative stress that drive skeletal muscle damage in T2D. While patients with T2D also display relatively higher levels of circulating inflammatory markers in the serum, including high sensitivity-C-reactive protein, interleukin-6, and tumor necrosis factor-α that are independently linked with the deterioration of muscle function and sarcopenia in T2D. In fact, beyond reporting on the pathological consequences of both oxidative stress and inflammation, the current review highlights the importance of strengthening intracellular antioxidant systems to preserve muscle mass, strength, and function in individuals with T2D.

Aerobic Exercise Ameliorates Muscle Atrophy Induced by Methylglyoxal via Increasing Gastrocnemius and Extensor Digitorum Longus Muscle Sensitivity

Muscle atrophy is characterized by the loss of muscle function. Many efforts are being made to prevent muscle atrophy, and exercise is an important alternative. Methylglyoxal is a well-known causative agent of metabolic diseases and diabetic complications. This study aimed to evaluate whether methylglyoxal induces muscle atrophy and to evaluate the ameliorative effect of moderate-intensity aerobic exercise in a methylglyoxal-induced muscle atrophy animal model. Each mouse was randomly divided into three groups: control, methylglyoxal-treated, and methylglyoxal-treated within aerobic exercise. In the exercise group, each mouse was trained on a treadmill for 2 weeks. On the last day, all groups were evaluated for several atrophic behaviors and skeletal muscles, including the soleus, plantaris, gastrocnemius, and extensor digitorum longus were analyzed. In the exercise group, muscle mass was restored, causing in attenuation of muscle atrophy. The gastrocnemius and extensor digitorum longus muscles showed improved fiber cross-sectional area and reduced myofibrils. Further, they produced regulated atrophy-related proteins (i.e., muscle atrophy F-box, muscle RING-finger protein-1, and myosin heavy chain), indicating that aerobic exercise stimulated their muscle sensitivity to reverse skeletal muscle atrophy. In conclusion, shortness of the gastrocnemius caused by methylglyoxal may induce the dynamic imbalance of skeletal muscle atrophy, thus methylglyoxal may be a key target for treating skeletal muscle atrophy. To this end, aerobic exercise may be a powerful tool for regulating methylglyoxal-induced skeletal muscle atrophy.

Tat-CIAPIN1 Prevents Pancreatic β-Cell Death in hIAPP-Induced RINm5F Cells and T2DM Animal Model

It is well known that the cytokine-induced apoptosis inhibitor 1 (CIAPIN1) protein plays an important role in biological progresses as an anti-apoptotic protein. Human islet amyloid peptide (hIAPP), known as amylin, is caused to pancreatic β-cell death in type 2 diabetes mellitus (T2DM). However, the function of CIAPIN1 protein on T2DM is not yet well studied. Therefore, we investigated the effects of CIAPIN1 protein on a hIAPP-induced RINm5F cell and T2DM animal model induced by a high-fat diet (HFD) and streptozotocin (STZ). The Tat-CIAPIN1 protein reduced the activation of mitogen-activated protein kinase (MAPK) and regulated the apoptosis-related protein expression levels including COX-2, iNOS, Bcl-2, Bax, and Caspase-3 in hIAPP-induced RINm5F cells. In a T2DM mice model, the Tat-CIAPIN1 protein ameliorated the pathological changes of pancreatic β-cells and reduced the fasting blood glucose, body weight and hemoglobin Alc (HbAlc) levels. In conclusion, the Tat-CIAPIN1 protein showed protective effects against T2DM by protection of β-cells via inhibition of hIAPP toxicity and by regulation of a MAPK signal pathway, suggesting CIAPIN1 protein can be a therapeutic protein drug candidate by beneficial regulation of T2DM.

Oxidative stress: roles in skeletal muscle atrophy

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.

Clinically Meaningful Fatigue and Depression Are Associated with Sarcopenia in Patients with Non-Alcoholic Fatty Liver Disease

BACKGROUND

Sarcopenia is thought to be related to an increased risk of non-alcoholic steatohepatitis and advanced liver fibrosis. Our cross-sectional single-center study was designed to analyze the prevalence of sarcopenia in patients with NAFLD and possible influencing factors.

METHODS

A survey on the presence of sarcopenia, fatigue, anxiety, and depression, along with a quality-of-life (QoL) assessment, was forwarded by email to 189 outpatients. Demographics, anthropometric and clinical data (laboratory test results and abdomen complete ultrasound protocol), performed within 2-4 weeks prior to the enrollment, were obtained.

RESULTS

Sarcopenia (defined as SARC-F score ≥ 4) was identified in 17 (15.7%) patients, all of them (100%) females, with median age (interquartile range) 56 (51-64) years. These patients had a poorer metabolic state (greater values of waist and hip circumferences, body mass index, and HOMA-IR) and significantly poorer QoL, specifically, regarding the physical component of health, compared with NAFLD patients without sarcopenia. Multivariate analysis showed that depression (OR = 1.25, 95% CI: 1.02-1.53, p = 0.035) and clinically meaningful fatigue (OR = 1.14, 95% CI: 1.04-1.26, p = 0.008) were the factors independently associated with sarcopenia in patients with NAFLD.

CONCLUSION

Sarcopenia is associated with depression and fatigue rather than with the severity of liver disease alone and may negatively affect QoL in patients with NAFLD.

Leucine and Glutamic Acid as a Biomarker of Sarcopenic Risk in Japanese People with Type 2 Diabetes

This study aimed to identify the serum metabolites associated with sarcopenic risk in Japanese patients with type 2 diabetes, determine the effect of dietary protein intake on the serum metabolic profile, and examine its association with sarcopenia. Ninety-nine Japanese patients with type 2 diabetes were included, and sarcopenic risk was defined as low muscle mass or strength. Seventeen serum metabolites were quantified after gas chromatography-mass spectrometry analysis. The relationship between dietary protein intake and the metabolites concerning sarcopenia was analyzed, and the factors affecting sarcopenic risk were clarified. Twenty-seven patients were classified as being at risk of sarcopenia, the same as the general risk, which was associated with older age, a longer duration of the disease, and a lower body mass index. Low levels of leucine and glutamic acid were significantly associated with low muscle strength (p = 0.002 and p < 0.001, respectively), and leucine was also associated with muscle mass (p = 0.001). Lower levels of glutamic acid had higher odds of sarcopenic risk after being adjusted for age and HbA1c (adjusted OR 4.27, 95% CI 1.07-17.11, p = 0.041), but not for leucine. Leucine and glutamic acid can serve as useful biomarkers for sarcopenia, highlighting potential targets for its prevention.