Hyperglycemia induces skeletal muscle atrophy via a WWP1/KLF15 axis

Estradiol inhibits endometrial injury by promoting the stability of the KLF15 protein and the recovery of mitochondrial function

BACKGROUND

Endometrial injury (EI) is an important factor leading to infertility, which seriously affects women's fertility and reproductive health. Research indicates that estradiol (E2) therapy can promote the repair of EI, but the specific mechanism of E2 action in EI remains unclear.

METHODS

The research involved creating an EI model for human endometrial epithelial cells (hEECs) using lipopolysaccharide (LPS), and constructing a rat intrauterine adhesion (IUA) model through simulating mechanical injury of human endometrial. Western blot, immunohistochemistry and RT-qPCR were used to detect the expression of key proteins and genes; endometrial damage was detected by HE, TUNEL and Masson staining; mitochondrial function changes were detected by detecting ROS, ATP levels and mitochondrial membrane potential.

RESULTS

Our research revealed a reduced expression of E2 and Krüppel-like factor 15 (KLF15) in IUA rats. Exogenous E2 treatment inhibited EI by activating the expression of KLF15, inhibited the expression of apoptosis-related proteins Bax and cleaved caspase-3, and promoted the expression of Bcl-2 protein. Additionally, our findings revealed that treatment with E2 decreased mitochondrial ROS (mROS) levels, enhanced mitochondrial membrane potential, and promoted ATP production in EI model cells, whereas KLF15 interference weakens the therapeutic effect of E2, suggesting that E2 treatment alleviates EI by promoting the expression of KLF15 and restoring mitochondrial function. In addition, E2 promotes PGC-1α expression by inhibiting WWP1-mediated ubiquitination degradation of KLF15, thereby restoring mitochondrial function and easing the development of EI.

CONCLUSION

Our study reveals that E2 alleviates EI progression by stabilizing KLF15 protein and restoring mitochondrial function, providing potential targets for EI treatment.

Chronic administration of tetrahydrofuran extracts of Cochlospermum vitifolium (Wild) Sprengel in a mouse diabetes model: Hypoglycemic, antioxidant, and genoprotective effects

Diabetes and its complications represent a major global health burden, contributing to rising mortality rates, escalating healthcare costs, and an increasing prevalence worldwide. This has driven renewed interest in traditional medicine as a complementary approach to disease management. Cochlospermum vitifolium (Wild) Sprengel, a medicinal plant traditionally used to treat kidney pain, liver disorders (including hepatitis C and jaundice), and metabolic syndrome, has demonstrated promising antidiabetic potential. Previous studies report hypoglycemic effects in both in vitro and short-term in vivo models. In this study, we evaluated the hypoglycemic activity of tetrahydrofuran (THF) extracts from C. vitifolium heartwood and bark in mice over a six-week period (500 mg/kg dose). The heartwood extract exhibited notable antioxidant activity, scavenging over 50 % of DPPH radicals at 3.2 mg/mL, while the bark extract showed higher potency at 1.5 mg/mL. Both extracts demonstrated genoprotective effects at doses of 250 and 500 mg/kg, mitigating damage from mutagenic agents. Notably, the heartwood extracts significantly reduced blood glucose levels from > 300 mg/dL to < 100 mg/dL, whereas the bark extract had no significant hypoglycemic effect. These findings suggest that C. vitifolium extracts, particularly from the heartwood, may modulate oxidative stress-related pathways implicated in chronic degenerative diseases such as diabetes. Further research is warranted to elucidate the underlying mechanisms and long-term safety profile of these extracts.

Analysis of the mechanism of skeletal muscle atrophy from the pathway of decreased protein synthesis

Skeletal muscle atrophy is associated with denervation, cancer, diabetes, aging, immobilization, and inflammation, which can significantly impair mobility. It is primarily attributable to increased protein catabolism alongside reduced protein synthesis, although the precise mechanisms underlying this process are not yet fully known. Unlike in the pathway driving increased catabolism, fewer studies have explored the mechanism underpinning muscle atrophy under reduced protein synthesis. Therefore, this study aimed to focus on summarizing relevant studies on the reduction of protein synthesis leading to skeletal muscle atrophy, as driven by alterations in pathways such as the insulin-like growth factor-1-phosphatidylinositol 3-kinase-protein kinase B-rapamycin signaling pathway, glycogen synthase kinase-3, glucocorticoids, 5'-adenosine monophosphate-activated protein kinase, branched-chain amino acid sensors, myostatin, long-term proinflammatory factors, oxidative stress and mitochondrial dysfunction, calciumion concentration, activating transcription factor 4, and glycyl-tRNA synthetase alterations. Consolidating these data will provide a foundation and theoretical basis for further investigation into the mechanisms of muscle atrophy from the perspective of reduced protein synthesis pathways.

Biomarkers of Skeletal Muscle Atrophy Based on Atrogenes Evaluation: A Systematic Review and Meta-Analysis Study

Muscle atrophy leads to decreased muscle mass, weakness, inactivity, and increased mortality. E3 ubiquitin ligases, key regulators of protein degradation via the ubiquitin-proteasome system, play a critical role in atrophic mechanisms. This meta-analysis followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, and its objective was to evaluate the association between E3 ligases Muscle Atrophy F-box (MAFbx)/Atrogin-1 (Fbxo32) and Muscle RING-finger protein 1 (MuRF-1) (TRIM63) E3 ligase mRNA levels, reductions in skeletal muscle CSA measures, and atrophy conditions. We examined papers published on PubMed®, Scopus, and Web of Science that studied E3 ligase gene expression signatures for Fbxo32 (MAFbx/Atrogin-1) and Trim63 (MuRF1) in different types of muscle atrophy and hypertrophy murine models. Twenty-nine studies selected by two independent raters were analyzed. Standardized mean differences (SMDs)/effect sizes (ESs) and 95% confidence intervals (CIs) were calculated for the outcomes using fixed-effects models. We found that 6- and 4.8-fold upregulation, respectively, of Fbxo32 and Trim63 was sufficient to reduce the ES to -3.89 (95% CI: -4.45 to -3.32) for the muscle fiber cross-sectional area and the development of skeletal muscle atrophy. I² and Q test statistics did not indicate heterogeneous data. There was a low probability of bias after both the funnel plot and Egger's test analyses. These results were sustained independently of the atrophic model and muscle type. Therefore, the magnitude of the increase in muscle Fbxo32 and Trim63 mRNA is a feasible, reliable molecular marker for skeletal muscle atrophy in mice. The next step for the Ubiquitin-proteasome system (UPS) field involves elucidating the targets of E3 ligases, paving the way for diagnostic and treatment applications in humans.

Nutritional Approach to Diabetic Sarcopenia: A Comprehensive Review

PURPOSE OF THE REVIEW

The aim of this review is to discuss and evaluate diabetic sarcopenia (DS) and its relationship with nutrition by discussing the mechanisms of diabetic sarcopenia in detail and comprehensively reviewing the literature.

RECENT FINDINGS

Type 2 diabetes (T2DM) affects approximately 25% of people aged 50 years and over and indicates a significant the cost of health for the elderly. Nutrition is an important part of these treatment approaches, and in this review, the literature was comprehensively reviewed, focusing on understanding the mechanisms of DS and discussing its relationship with nutrition. A comprehensive search was conducted on Web of Science, Google Scholar, Scopus, Science Direct, and PubMed from inception up to July 2024. The aim of nutritional treatment for DS is to improve muscle mass, muscle strength and physical performance while improving diabetes-related metabolic risk and glucose levels. In this context, it is important to determine energy intake in individuals with DS according to calorie intake exceeding 30 kcal/kg. For these individuals, a protein intake of at least 1-1.2 g/kg/day is recommended, with an emphasis on the number and timing of meals and a nutritional pattern rich in branched chain amino acids (BCAA). In addition, it is important to adopt a diet rich in antioxidants and to choose diet patterns that contain sufficient levels of macro and micronutrients. The Mediterranean diet model can be a good diet option for individuals with DS. Comprehensive studies in this field are needed so that clinicians can make specific dietary recommendations for DS.

High-intensity interval training alleviates STZ-induced muscle atrophy by restoration of nuclear positioning defects in C57BL/6 male mice

We tested the hypothesis that improper myonuclei arrangement and morphology are involved in diabetes-induced myofiber atrophy and whether and how high-intensity interval training (HIIT) affects these impairments in isolated skeletal muscle myofibers. STZ-induced diabetes decreased muscle fiber cross-sectional area (CSA) mediated by reduced myonuclear number, enhanced nuclear apoptotic, and failed nuclear accretion from satellite cells. STZ-induced muscle atrophy was accompanied by improper nuclear positioning (sinus of the maximum diameter angles and distance between adjacent myonuclei) and morphology (maximum diameter, area, and volume of the nuclei), which was mediated by suppressed expression of proteins involved in nuclear positioning including KIF5B, dynein, and Nesprin1. Disturbing nuclear positioning by inhibition of Kinsein1 activity reduced CSA to a greater extent than in diabetes alone, suggesting STZ-induced muscle atrophy is mediated by changes in nuclear positioning. HIIT alleviated the STZ-induced decline in muscle CSA and myonuclei per fiber by restoring myonuclear morphometry impairments and improper nuclear positioning to the normal level. HIIT-induced increase in muscle CSA deterred by inhibition of Kinesin1 activity, suggesting its effect is mediated by proper nuclear positioning. These findings suggest that normal nuclear positioning are required for the changes in fiber size properties associated with HIIT in diabetic skeletal muscle fibers.

Are strategies to increase muscle mass and strength as effective in people with type 2 diabetes?

People with type 2 diabetes (T2D) have a 2-3-time higher risk of developing sarcopenia, a musculoskeletal disease marked by a progressive loss of skeletal muscle mass and strength, compared to people without T2D. This narrative review examines the effectiveness of lifestyle interventions in enhancing muscle mass and strength in people with T2D, emphasizing their growing importance with advancements in obesity treatments. PubMed and Google Scholar were utilized to identify the most relevant published studies based on the authors' knowledge. The maintenance of skeletal muscle strength and mass in people with T2D is becoming more prominent due to the advent of weight loss therapies such as low-energy diets, bariatric surgery and pharmacotherapies. Although the weight loss is to be commended, a large proportion (20-50%) of the weight loss comes from lean mass, indicative of a loss in muscle mass. There are currently no pharmacotherapies to increase, or mitigate the loss of, lean mass, with lifestyle strategies prominent in this arena. Resistance exercise is the most effective method to increase muscle mass and strength in people with T2D, but there is some evidence of an anabolic resistance. Aerobic exercise and increased dietary protein intake may result in small increases in muscle mass and strength, with no evidence of an anabolic resistance to these stimuli. Exercise and protein supplementation can increase, or aid in the retention of, muscle strength and mass in individuals with T2D, but further research is needed to explore their benefits in patients undergoing concomitant pharmaceutical and surgical treatments.

Transcriptional regulation of autophagy in skeletal muscle stem cells

Muscle stem cells (MuSCs) are essential for the regenerative capabilities of skeletal muscles. MuSCs are maintained in a quiescent state, but, when activated, can undergo proliferation and differentiation into myocytes, which fuse and mature to generate muscle fibers. The maintenance of MuSC quiescence and MuSC activation are processes that are tightly regulated by autophagy, a conserved degradation system that removes unessential or dysfunctional cellular components via lysosomes. Both the upregulation and downregulation of autophagy have been linked to impaired muscle regeneration, causing myopathies such as cancer cachexia, sarcopenia and Duchenne muscular dystrophy. In this Review, we highlight the importance of autophagy in regulating MuSC activity during muscle regeneration. Additionally, we summarize recent studies that link the transcriptional dysregulation of autophagy to muscle atrophy, emphasizing the dominant roles that transcription factors play in myogenic programs. Deciphering and understanding the roles of these transcription factors in the regulation of autophagy during myogenesis could advance the development of regenerative medicine.

The Stimulator of Interferon Genes Deficiency Attenuates Diabetic Myopathy Through Inhibiting NLRP3-Mediated Pyroptosis

BACKGROUND

Diabetic myopathy is characterized by the loss of skeletal muscle mass and function. NOD-like receptor family pyrin domain containing 3 (NLRP3)-mediated pyroptosis is a type of proinflammatory cell death, which can exacerbate significant muscle cell loss and adverse remodelling. The stimulator of interferon genes (STING) is an essential molecule involved in the regulation of inflammation and immune responses across various diseases. The regulatory mechanism by which STING affects muscle pyroptosis in diabetic myopathy remains unclear.

METHODS

STING-knockout and wild-type (WT) mice underwent intraperitoneal injection of streptozotocin (STZ). STING small interfering RNA (siRNA) was transfected into fully differentiated C2C12 myotubes prior to glucose treatment. Muscle function tests, body composition analysis, transmission electron microscopy, scanning electron microscopy, western blotting, immunofluorescence, immunohistochemistry, histology, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction were performed. Co-immunoprecipitation assays were employed to investigate the interaction between STING and NLRP3.

RESULTS

STING expression was elevated in the gastrocnemius muscle (GM) tissues of WT diabetic mice. STING-deficient diabetic mice exhibited pronounced hyperglycaemia accompanied by hypoinsulinaemia, with no significant difference compared with WT diabetic mice. However, STING-deficient diabetic mice demonstrated a significantly increased body weight and lean mass. A significant decrease in muscle weight, myofibrillar diameter and area, muscle function, and the expression of genes related to muscle atrophy (MuRF1, Atrogin1) were observed in WT diabetic mice, which was mitigated in STING-deficient diabetic mice. STING deficiency reduced the number of GSDMD-N formed pores and pyroptosis-related components (NLRP3, caspase-1, cle-caspase-1, GSDMD, and GSDMD-N) in the GM tissues and was associated with a reduction in inflammatory chemokines. Similar changes were observed in vitro with glucose-induced myotube atrophy and pyroptosis as seen in vivo. Activation of STING by the agonist diABZI exacerbated muscle atrophy and pyroptosis in C2C12 myotubes. Co-localization of STING and NLRP3 was observed, and the interaction between STING and NLRP3 was enhanced in GM tissues from WT diabetic mice. We also found that STING could activate NLRP3 dependent on its channel activity, which can be attenuated by treated with C53 (an inhibitor of STING's ion-channel function).

CONCLUSIONS

In conclusion, our results indicate that STING-induced activation of the NLRP3 inflammasome leads to pyroptosis, resulting in muscle atrophy and dysfunction. These findings not only elucidate the mechanism of STING-induced pyroptosis but also identify STING as a potential therapeutic target for diabetic myopathy.

Therapeutic potential of 4-hexylresorcinol in reducing sarcopenia in diabetic masseter muscle

BACKGROUND

This study aimed to evaluate the effects of 4-hexylresorcinol (4HR), a synthetic compound with antioxidant and stress-modulating properties, on diabetic sarcopenia in the masseter muscle.

METHODS

A controlled, parallel-arm study was conducted using 38 Sprague-Dawley rats divided into diabetic and non-diabetic groups. Diabetes was induced with streptozotocin (STZ), and the groups were further subdivided to receive weekly subcutaneous injections of either 4HR or saline. Muscle volume was assessed using micro-computed tomography (μCT), and glycogen storage and protein expression were analyzed using periodic acid-Schiff (PAS) staining and immunohistochemistry.

RESULTS

μCT analysis revealed that diabetic rats exhibited significantly reduced masseter muscle volume compared to non-diabetic rats. However, 4HR treatment partially mitigated muscle volume loss in diabetic animals. Histological analysis showed higher PAS staining intensity in the diabetic group treated with 4HR compared to the untreated diabetic group, suggesting improved glycogen storage. Immunohistochemistry demonstrated that 4HR treatment significantly increased Glut4 and phosphorylated AMPKα (p-AMPKα) expression in diabetic muscle, indicating enhanced glucose uptake and metabolic activity.

CONCLUSIONS

4HR effectively alleviates diabetes-induced sarcopenia by preserving muscle volume, enhancing glycogen storage, and upregulating Glut4 and p-AMPKα expression. These findings suggest that 4HR holds potential as a therapeutic agent for combating muscle wasting in diabetes.

Type 2 Diabetes Induces Mitochondrial Dysfunction in Zebrafish Skeletal Muscle Leading to Diabetic Myopathy via the miR-139-5p/NAMPT Pathway

Type 2 diabetes mellitus (T2DM) is a common metabolic disease that is frequently accompanied by multiple complications, including diabetic myopathy, a muscle disorder that is mainly manifested as decreased muscle function and reduced muscle mass. Diabetic myopathy is a relatively common complication among patients with diabetes that is mainly attributed to mitochondrial dysfunction. Therefore, we investigated the mechanisms underlying diabetic myopathy development, focusing on the role of microRNAs (miRs). Zebrafish were fed a high-sugar diet for 8 weeks and immersed in a glucose solution to establish a model of T2DM. Notably, the fish exhibited impaired blood glucose homeostasis, increased lipid accumulation in the skeletal muscles, and decreased insulin levels in the skeletal muscle. Additionally, we observed various symptoms of diabetic myopathy, including a decreased cross-sectional area of skeletal muscle fibers, increased skeletal muscle fibrosis, a significant decline in exercise capacity, and a significant decrease in mitochondrial respiratory function. Mechanistically, bioinformatic analysis combined with various molecular analyses showed that the miR-139-5p/NAMPT pathway was involved in long-term high-glucose-induced mitochondrial dysfunction in the skeletal muscle, leading to diabetic myopathy. Conclusively, this study provides a basis for the development of novel strategies for the prevention and treatment of diabetic myopathy.

Thermally processed rice starch impacts glucose homeostasis in mice to different degrees via disturbing gut microbial structure and intestinal barrier function

Long-term intake of thermally processed starch-based foods may impact glucose homeostasis, but the consistency of the effects of various thermal treatments and the reasons are not clear. In this study, thermal treatments, especially boiling, damaged the crystal structure and inter-molecular hydrogen bonds of starch-based blends, thus decreasing the structural order and stability. These thermally treated starch-based blends increased the appetite of mice, promoted food digestion, and enhanced postprandial glucose response. Normal C57BL/6J mice were treated with boiled, baked, and fried starch-based diets for ten weeks. Compared to the baked and fried starch-based diets, the boiled starch-based diet significantly (p < 0.05) elevated random blood glucose levels and disrupted insulin homeostasis, primarily due to the remarkable decrease in gut microbial diversity. Both baked and fried starch-based diets resulted in relatively high intestinal epithelial permeability (plasma lipopolysaccharide increased by 28.67 % and 21.85 %, respectively). They adversely affected islet β-cell function and evoked glucose metabolism disorder. Overall, results demonstrate a clear connection among the thermal processing of starch-based diets, disruption of intestinal homeostasis, and adverse glucose metabolism. This study lays a theoretical foundation for the formulation of food processing strategies to mitigate the adverse effects of thermally treated food on glucose homeostasis.

Effects of Type II Diabetes on upper extremity muscle characteristics in older adults

With one in every four older adults living with T2D and one in every two older adults meeting the criteria for prediabetes, neuromuscular changes due to T2D are likely to impact functional activities in this population. Limited work in evaluating motor unit number and size across muscles in the upper extremity in persons with Type II Diabetes (T2D) exists, mostly due to the traditional belief bias that the upper extremity is relatively spared in T2D as compared to the lower extremities. The purpose of the current study was to evaluate motor unit number and size (using electrophysiological motor unit number index (MUNIX) and motor unit size index (MUSIX)) across the upper extremity in older adults with T2D (n = 13) as compared to healthy age- and sex-matched controls (n = 12). Persons with T2D presented with more motor units and larger motor unit sizes (p < 0.05) as compared to age- and sex-matched control participants. These changes were not dependent upon muscle location within a limb, indicating systemic neuromuscular changes associated with T2D. These group effects were clarified when health state covariates (e.g., blood pressure) were accounted for. Findings are consistent with emerging data that show altered neuromuscular characteristics with health state considerations in persons with T2D.

Primary Roles of Branched Chain Amino Acids (BCAAs) and Their Metabolism in Physiology and Metabolic Disorders

Leucine, isoleucine, and valine are collectively known as branched chain amino acids (BCAAs) and are often discussed in the same physiological and pathological situations. The two consecutive initial reactions of BCAA catabolism are catalyzed by the common enzymes referred to as branched chain aminotransferase (BCAT) and branched chain α-keto acid dehydrogenase (BCKDH). BCAT transfers the amino group of BCAAs to 2-ketoglutarate, which results in corresponding branched chain 2-keto acids (BCKAs) and glutamate. BCKDH performs an oxidative decarboxylation of BCKAs, which produces their coenzyme A-conjugates and NADH. BCAT2 in skeletal muscle dominantly catalyzes the transamination of BCAAs. Low BCAT activity in the liver reduces the metabolization of BCAAs, but the abundant presence of BCKDH promotes the metabolism of muscle-derived BCKAs, which leads to the production of glucose and ketone bodies. While mutations in the genes responsible for BCAA catabolism are involved in rare inherited disorders, an aberrant regulation of their enzymatic activities is associated with major metabolic disorders such as diabetes, cardiovascular disease, and cancer. Therefore, an understanding of the regulatory process of metabolic enzymes, as well as the functions of the BCAAs and their metabolites, make a significant contribution to our health.

Skeletal Muscle Mass Loss and Physical Function in Young to Middle-Aged Adult Patients With Diabetes: Cross-Sectional Observational Study

BACKGROUND

Recently, it has been reported that older adults with type 2 diabetes mellitus (T2DM) have lower skeletal muscle mass than healthy individuals. Although skeletal muscle mass in older adults with diabetes is occasionally reported, similar reports on young to middle-aged adults are limited.

OBJECTIVE

This study aims to assess the prevalence of skeletal muscle loss in young to middle-aged adults with diabetes, examine the relationship between skeletal muscle loss and physical function in these patients, and examine whether there are differences in these characteristics between men and women.

METHODS

This cross-sectional, observational study included patients younger than 65 years with T2DM who were admitted to our hospital between 2014 and 2022 for educational admission for glycemic control and requested rehabilitation by the Department of Metabolic Medicine. The control group consisted of patients who received rehabilitation during their hospitalization at our hospital and did not have diabetes. The main parameters included skeletal muscle mass, muscle strength, physical function, and activities of daily living.

RESULTS

The prevalence of skeletal muscle mass loss in this study was 18.2% (10/55) in men and 7.7% (4/52) in women. The skeletal muscle mass index (SMI) was 7.7 (SD 0.8) and 8.4 (SD 0.5) for men in the T2DM and control groups, respectively, and 7.0 (SD 0.9) and 6.8 (SD 0.7) for women in the T2DM and control groups, respectively. Therefore, compared with the nondiabetes group, a significant difference was observed in men but not in women (men: P<.001, women: P=.35). Nonetheless, the diabetes group exhibited significantly lower physical functions, such as a walking speed of 1.3 (SD 0.2) m/s and 1.2 (SD 0.43) m/s for men and women in the T2DM group and 1.6 (SD 0.2) m/s and 1.5 (SD 0.1) m/s for men and women in the control group, respectively (men: P<.001, women: P<.001). One-leg standing time was measured as 30.7 (SD 26.9) seconds and 29.4 (SD 25.5) seconds for men and women in the T2DM group, compared with 100.5 (SD 30.6) seconds and 82.5 (SD 39.8) seconds for men and women in the control group, respectively, with the T2DM group's times being significantly lower (men: P<.001, women: P<.001). Univariate logistic regression analysis showed that SMI was significantly associated with age, BMI, and peripheral neuropathy (all P≤.002). Multiple logistic regression analysis showed that BMI exhibited the strongest association (odds ratio 1.15, 95% CI 1.07-1.23; P<.001), and peripheral neuropathy was also significantly associated with SMI (P=.009).

CONCLUSIONS

Patients with diabetes, even those who are not older adults, face an elevated rate of skeletal muscle mass loss, muscle weakness, and a decline in physical function; moreover, they are susceptible to dynapenia and presarcopenia. Therefore, early intervention focusing on muscle evaluation and exercise is crucial.

Urinary titin as an early biomarker of skeletal muscle proteolysis and atrophy in various catabolic conditions

Skeletal muscle atrophy impairs quality of life and increases the risk of disease, but current methods for assessment of muscle mass have several limitations. We here investigated the urinary concentration of a fragment of the muscle protein titin as a potential biomarker for the early detection of skeletal muscle atrophy. Four mouse models with different atrophy pathways were studied: those of cardiotoxin-induced acute muscle injury, cast-induced muscle immobilization, lipopolysaccharide-induced sepsis, and streptozotocin-induced diabetes. In all four models, urinary titin levels increased early, concurrent with or preceding upregulation of the atrophy-related genes for atrogin-1 and MuRF-1. The increase in the urinary titin concentration was thus associated with initial muscle damage and the onset of proteolysis, rather than with late-stage muscle wasting. Our findings suggest that urinary titin is a promising biomarker for detection of the onset of skeletal muscle catabolism and prediction of the subsequent development of atrophy in different catabolic states. Noninvasive measurement of urinary titin may therefore allow the earlier detection of skeletal muscle proteolysis compared with conventional techniques.

Deciphering the mechanisms and effects of hyperglycemia on skeletal muscle atrophy

Hyperglycemia, a hallmark of diabetes mellitus, significantly contributes to skeletal muscle atrophy, characterized by progressive muscle mass and strength loss. This review summarizes the mechanisms of hyperglycemia-induced muscle atrophy, examines clinical evidence, and discusses preventive and therapeutic strategies. A systematic search of electronic databases, including PubMed, Scopus, and Web of Science, was conducted to identify relevant papers on hyperglycemic skeletal muscle atrophy. Key mechanisms include insulin resistance, chronic inflammation, oxidative stress, and mitochondrial dysfunction. Crucial molecular pathways involved are Phosphoinositide 3-kinase/Protein kinase B signaling, Forkhead box O transcription factors, the ubiquitin-proteasome system, and myostatin-mediated degradation. Hyperglycemia disrupts normal glucose and lipid metabolism, exacerbating muscle protein degradation and impairing synthesis. Clinical studies support the association between hyperglycemia and muscle atrophy, emphasizing the need for early diagnosis and intervention. Biomarkers, imaging techniques, and functional tests are vital for detecting and monitoring muscle atrophy in hyperglycemic patients. Management strategies focus on glycemic control, pharmacological interventions targeting specific molecular pathways, nutritional support, and tailored exercise regimens. Despite these advances, research gaps remain in understanding the long-term impact of hyperglycemia on muscle health and identifying novel therapeutic targets. The review aims to provide a comprehensive understanding of the mechanisms, clinical implications, and potential therapeutic strategies for addressing hyperglycemia-induced skeletal muscle atrophy.

Contractile regulation of the glucocorticoid-sensitive transcriptome in young and aged skeletal muscle

Elevated glucocorticoids alter the skeletal muscle transcriptome to induce a myopathy characterized by muscle atrophy, muscle weakness, and decreased metabolic function. These effects are more likely to occur and be more severe in aged muscles. Resistance exercise can blunt the development of glucocorticoid myopathy in young muscle, but the potential to oppose the signals initiating myopathy in aged muscle is unknown. To answer this, young (4-mo-old) and aged (24-to 25-mo-old) male C57BL/6 mice were randomized to receive either an intraperitoneal (IP) injection of dexamethasone (DEX; 2 mg/kg) or saline as a control. Two hours postinjections, the tibialis anterior (TA) muscles of mice were subjected to unilateral high-force contractions. Muscles were harvested 4 h later. The glucocorticoid- and contraction-sensitive genes were determined by RNA sequencing. The number of glucocorticoid-sensitive genes was similar between young and aged muscle. Contractions opposed changes to more glucocorticoid-sensitive genes in aged muscle, with this outcome primarily occurring when hormone levels were elevated. Glucocorticoid-sensitive gene programs opposed by contractions were primarily related to metabolism in young mice and muscle size regulation and inflammation in aged mice. In silico analysis implied peroxisome proliferator-activated receptor gamma-1 (PPARG) contributed to the contraction-induced opposition of glucocorticoid-sensitive genes in aged muscle. Increasing PPARG expression in the TA of aged mice using adeno-associated virus serotype 9 partially counteracted the glucocorticoid-induced reduction in runt-related transcription factor 1 (Runx1) mRNA content, recapitulating the effects observed by contractions. Overall, these data contribute to our understanding of the contractile regulation of the glucocorticoid transcriptome in aged skeletal muscle.NEW & NOTEWORTHY We establish the extent to which muscle contractions oppose changes to the glucocorticoid-sensitive transcriptome in both young and aged muscle. We also identify peroxisome proliferator-activated receptor gamma (PPARG) as a transcription factor likely contributing to contraction-induced opposition to the glucocorticoid transcriptome in aged muscle. Overall, these data contribute to our understanding of the contractile regulation of the glucocorticoid transcriptome.

The role of amino acids in skeletal muscle health and sarcopenia: A narrative review

The skeletal muscle is the largest organ present inside the body and is responsible for mechanical activities like maintaining posture, movement, respiratory function, and support for the health and functioning of other systems of the body. Skeletal muscle atrophy is a condition associated with a reduction in muscle size, strength, and activity, which leads to an increased dependency on movement, an increased risk of falls, and a reduced quality of life. Various conditions like osteoarthritis, osteoporosis, and fractures are directly associated with an increased muscle atrophy. Additionally, numerous risk factors, like aging, malnutrition, physical inactivity, and certain disease conditions, through distinct pathways negatively affect skeletal muscle health and lead to muscle atrophy. Among the various determinants of the overall muscle health, the rate of muscle protein synthesis and degradation is an important parameter that eventually alters the fate of overall muscle health. In conditions of excessive skeletal muscle atrophy, including sarcopenia, the rate of muscle protein degradation usually exceeds the rate of protein synthesis. The availability of amino acids in the systemic circulation is a crucial step for muscle protein synthesis. The current review aimed to consolidate the existing evidence of amino acids, highlight their mechanisms of action, and assess their roles and effectiveness in enhancing skeletal muscle health.

Downregulation of Krüppel-like factor 15 expression delays endochondral bone ossification during fracture healing

OBJECTIVE

The role of Krüppel-like zinc finger transcription factor 15 (KLF15) in endochondral ossification during fracture healing remains unexplored. In this study, we aimed to elucidate the impact of KLF15 in a mouse model of tibial transverse fracture.

METHODS

We created tamoxifen-inducible, cartilage-specific KLF15 knockout mice (KLF15 KO). KLF15 fl/fl Col2-CreERT mice from the same litters as the KLF15 KO mice, but not treated with 4-hydroxytamoxifen, were used as controls (CT). At 10 weeks, male KLF15 KO and CT mice underwent tibial fracture followed by intramedullary nailing. Both groups were administered tamoxifen at days 0, 3, and 7 after surgery. The tibiae were harvested on post-surgery days 7, 10, and 14 for radiological assessment using micro-computed tomography. Histological staining (Safranin-O) and immunohistochemistry for KLF15, SOX9, Indian hedgehog (IHH), RUNX2, and Osterix were performed. Additionally, cartilage from mouse fetus was cultured for qRT-PCR and western blot analyses of KLF15, SOX9, IHH, Col2, RUNX2, Osterix, TGF-β, SMAD3, and phosphor-SMAD3.

RESULTS

The radiological assessment revealed that immature callus formation was delayed in KLF15 KO, compared with that in CT, peaking on day 14 compared with that on day 10 in CT. KLF15 KO mice exhibited delayed fracture healing and reduced Safranin-O staining at days 7 and 10 post-surgery. The ratio of cells positive for KLF15 and SOX9 was significantly lower in KLF15 KO than in CT, whereas the ratios for IHH, RUNX2, and Osterix showed no significant difference. RT-PCR revealed reduced expression of KLF15, SOX9, and COL2, with no significant changes in IHH, Osterix, RUNX2, TGF-β, and SMAD3. Western blot analysis indicated decreased SMAD3 phosphorylation in KLF15 KO mice.

CONCLUSION

KLF15 regulates SOX9 via the TGF-β-SMAD3-SOX9 pathway, independent of IHH, in endochondral ossification. The KLF15 deficiency decreases SOX9 expression through reduced SMAD3 phosphorylation, subsequently delaying fracture healing.

The role of ubiquitination in health and disease

Ubiquitination is an enzymatic process characterized by the covalent attachment of ubiquitin to target proteins, thereby modulating their degradation, transportation, and signal transduction. By precisely regulating protein quality and quantity, ubiquitination is essential for maintaining protein homeostasis, DNA repair, cell cycle regulation, and immune responses. Nevertheless, the diversity of ubiquitin enzymes and their extensive involvement in numerous biological processes contribute to the complexity and variety of diseases resulting from their dysregulation. The ubiquitination process relies on a sophisticated enzymatic system, ubiquitin domains, and ubiquitin receptors, which collectively impart versatility to the ubiquitination pathway. The widespread presence of ubiquitin highlights its potential to induce pathological conditions. Ubiquitinated proteins are predominantly degraded through the proteasomal system, which also plays a key role in regulating protein localization and transport, as well as involvement in inflammatory pathways. This review systematically delineates the roles of ubiquitination in maintaining protein homeostasis, DNA repair, genomic stability, cell cycle regulation, cellular proliferation, and immune and inflammatory responses. Furthermore, the mechanisms by which ubiquitination is implicated in various pathologies, alongside current modulators of ubiquitination are discussed. Enhancing our comprehension of ubiquitination aims to provide novel insights into diseases involving ubiquitination and to propose innovative therapeutic strategies for clinical conditions.

Efficacy of a Benincasa hispida powdered drink in improving metabolic control in patients with type 2 diabetes: A placebo-controlled study

Objectives

There is emerging evidence of the benefits of Benincasa hispida in improving metabolic profiles in people with diabetes. This study was conducted to analyze the effect of B. hispida aqueous extract on the metabolic control of patients with type 2 diabetes in Malaysia.

Methods

A powdered drink formulated with 2.5 g of B. hispida extract was prepared as a test food. An intervention study was conducted with 50 participants randomly assigned to an intervention or a control group. Anthropometric, biochemical, and clinical variables were assessed at baseline and week 12 after intervention. Paired T-tests were applied to compare the mean differences between the baseline and post-intervention for each variable.

Results

The intervention group presented a significant reduction in diastolic blood pressure (Δ -7.0 mmHg, 95% confidence interval [CI]: -11.4, -2.5). Mean fasting plasma glucose (Δ -0.8 mmol/L, 95% CI: -1.8, 0.2) showed a greater reduction in the intervention group compared to the control group (Δ -0.4 mmol/L, 95% CI: -1.2, 0.4). Mean lean body mass showed a favorable trend of increment at week 6 (Δ 0.05 kg, 95% CI: -0.40, 0.49) and week 12 (Δ 0.16 kg, 95% CI: -0.33, 0.64) as compared to baseline in the intervention group but not in the control group which manifested decreasing lean body mass.

Conclusion

The use of B. hispida extract may potentially improve blood pressure and glycemic control in patients with type 2 diabetes and it may be an attractive candidate for the development of functional food products.

Exendin-4, a glucagon-like peptide-1 receptor agonist, alleviates muscular dysfunction and wasting in a streptozotocin-induced diabetic mouse model compared to metformin

Diabetic muscular atrophy is becoming a fast-growing problem worldwide, including sarcopenia, which is associated with substantial mortality and morbidity risk. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been marketed and suggested to exert protective effects on not only glycemic control but also diabetic complications in diabetic patients. In this study, we investigated the therapeutic use of GLP-1RAs exendin-4, compared to antidiabetic drug metformin, for the intervention of muscular dysfunction during diabetic conditions using a streptozotocin (STZ)-induced diabetic mouse model. The results showed that both exendin-4 and metformin could effectively alleviate hyperglycemia in diabetic mice, and also counteract diabetes-induced muscle weight loss, weaker grip, and changes in muscle fiber cross-sectional area distribution. Unexpectedly, exendin-4, but not metformin, enhanced the increased kidney weight and histological change in diabetic mice. Taken together, these findings suggest that both exendin-4 and metformin could effectively improve the diabetic hyperglycemia and muscular dysfunction; but exendin-4 may aggravate the nephropathy in STZ-induced diabetic mice.

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.

Exploring mechanisms of insulin action and strategies to treat diabetes

Insulin is a hormone that positively regulates anabolism and cell growth, whereas diabetes mellitus is a disease characterized by hyperglycemia associated with impaired insulin action. My colleagues and I have elucidated multifaceted insulin action in various tissues mainly by means of model mice. In the liver, insulin regulates endoplasmic reticulum (ER) stress response during feeding, whereas ER stress 'response failure' contributes to the development of steatohepatitis comorbid with diabetes. Not only the liver but also the proximal tubules of the kidney are important in the regulation of gluconeogenesis, and we revealed that insulin suppresses gluconeogenesis in accordance with absorbed glucose in the latter tissue. In skeletal muscle, another important insulin-targeted tissue, impaired insulin/IGF-1 signaling leads not only to sarcopenia, an aging-related disease of skeletal muscle, but also to osteopenia and shorter longevity. Aging is regulated by adipokines as well, and it should be considered that aging could be accelerated by 'imbalanced adipokines' in patients with a genetic background of progeria. Moreover, we reported the effects of intensive multifactorial intervention on diabetic vascular complications and mortality in patients with type 2 diabetes in a large-scale clinical trial, the J-DOIT3, and the results of subsequent sub-analyses of renal events and fracture events. Various approaches of research enable us of endocrinologists to elucidate the physiology of hormone signaling, the mechanisms underlying the development of endocrine diseases, and the appropriate treatment measures. These approaches also raise fundamental questions, but addressing them in an appropriate manner will surely contribute to the further development of endocrinology.

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.

The Impact of Ulmus macrocarpa Extracts on a Model of Sarcopenia-Induced C57BL/6 Mice

Aging leads to tissue and cellular changes, often driven by oxidative stress and inflammation, which contribute to age-related diseases. Our research focuses on harnessing the potent anti-inflammatory and antioxidant properties of Korean Ulmus macrocarpa Hance, a traditional herbal remedy, to address muscle loss and atrophy. We evaluated the effects of Ulmus extract on various parameters in a muscle atrophy model, including weight, exercise performance, grip strength, body composition, muscle mass, and fiber characteristics. Additionally, we conducted Western blot and RT-PCR analyses to examine muscle protein regulation, apoptosis factors, inflammation, and antioxidants. In a dexamethasone-induced muscle atrophy model, Ulmus extract administration promoted genes related to muscle formation while reducing those associated with muscle atrophy. It also mitigated inflammation and boosted muscle antioxidants, indicating a potential improvement in muscle atrophy. These findings highlight the promise of Ulmus extract for developing pharmaceuticals and supplements to combat muscle loss and atrophy, paving the way for clinical applications.

Associations between fasting glucose rate-of-change and the missense variant, rs373863828, in an adult Samoan cohort

BACKGROUND

The A allele of rs373863828 in CREB3 regulatory factor is associated with high Body Mass Index, but lower odds of type 2 diabetes. These associations have been replicated elsewhere, but to date all studies have been cross-sectional. Our aims were (1) to describe the development of type 2 diabetes and change in fasting glucose between 2010 and 2018 among a longitudinal cohort of adult Samoans without type 2 diabetes or who were not using diabetes medications at baseline, and (2) to examine associations between fasting glucose rate-of-change (mmol/L per year) and the A allele of rs373863828.

METHODS

We describe and test differences in fasting glucose, the development of type 2 diabetes, body mass index, age, smoking status, physical activity, urbanicity of residence, and household asset scores between 2010 and 2018 among a cohort of n = 401 adult Samoans, selected to have a ~2:2:1 ratio of GG:AG: AA rs373863828 genotypes. Multivariate linear regression was used to test whether fasting glucose rate-of-change was associated with rs373863828 genotype, and other baseline variables.

RESULTS

By 2018, fasting glucose and BMI significantly increased among all genotype groups, and a substantial portion of the sample developed type 2 diabetes mellitus. The A allele was associated with a lower fasting glucose rate-of-change (β = -0.05 mmol/L/year per allele, p = 0.058 among women; β = -0.004 mmol/L/year per allele, p = 0.863 among men), after accounting for baseline variables. Mean fasting glucose and mean BMI increased over an eight-year period and a substantial number of individuals developed type 2 diabetes by 2018. However, fasting glucose rate-of-change, and type 2 diabetes development was lower among females with AG and AA genotypes.

CONCLUSIONS

Further research is needed to understand the effect of the A allele on fasting glucose and type 2 diabetes development. Based on our observations that other risk factors increased over time, we advocate for the continued promotion for diabetes prevention and treatment programming, and the reduction of modifiable risk factors, in this setting.

Association of short-term changes in HbA1c with body composition and the importance of muscle maintenance in patients with Type 2 diabetes

AIMS

This study aimed to investigate the relationship between changes in glucose metabolism and body composition in patients with diabetes.

METHODS

We included 380 patients with type 2 diabetes, who underwent bioelectrical impedance analysis, in this longitudinal study. Changes in HbA1c (ΔHbA1c) levels and body composition indices were compared between baseline and 6 months. A multivariate analysis was performed to examine the relationship between ΔHbA1c and changes in body composition.

RESULTS

HbA1c levels were significantly decreased at 6 months (P < 0.01), but there was no significant change in BMI. A linear multiple regression analysis showed that ΔHbA1c was negatively correlated with changes in muscle mass (β = -0.18; P = 0.047) and bone mineral content (β = -0.28; P < 0.001), but there was no significant association between ΔHbA1c levels and a change in body fat percentage.

CONCLUSIONS

This study shows a limited association between short-term changes in glucose metabolism and changes in body composition in patients with type 2 diabetes. Therefore, interventions aimed at reducing adiposity may not affect glucose metabolism in the short term, while interventions focused on maintaining or enhancing muscle mass and bone mineral content may play an important role in diabetes management.

Unlocking the Potential of Obestatin: A Novel Peptide Intervention for Skeletal Muscle Regeneration and Prevention of Atrophy

Obestatin is derived from the same gene as that of ghrelin and their functions were perceived to be antagonistic. Recent developments have shown that although they are known to have contradictory functions, effect of obestatin on skeletal muscle regeneration is similar to that of ghrelin. Obestatin works through a receptor called GPR39, a ghrelin and motilin family receptor and transduces signals in skeletal muscle similar to that of ghrelin. Not only there is a similarity in the receptor family, but also obestatin targets similar proteins and transcription factors as that of ghrelin (for example, FoxO family members) for salvaging skeletal muscle atrophy. Moreover, like ghrelin, obestatin also works by inducing the transcription of Pax7 which is required for muscle stem cell mobilisation. Hence, there are quite some evidences which points to the fact that obestatin can be purposed as a peptide intervention to prevent skeletal muscle wasting and induce myogenesis. This review elaborates these aspects of obestatin which can be further exploited and addressed to bring obestatin as a clinical intervention towards preventing skeletal muscle atrophy and sarcopenia.

How Gender-Targeted Body Image Concerns Influence People's Sugar-Sweetened Beverages Consumption

As excessive sugar intake can result in obesity, type 2 diabetes, cardiovascular disease, and even cancer, this study aims to help people reduce sugar-sweetened beverages (SSBs) intake by exploring how gender-differed body image concerns influence people's attitude and intention of SSBs consumption. A 2 (Participants' gender: Male vs. Female) × 2 (Image gender: Male vs. Female) × 2 (Body image concern: Gaining weight vs. Losing muscle mass) online experiment was conducted to examine how the gender-differed body image concerns influence people's perception of SSBs. The findings showed that gender-differed body image concerns exerted a significant influence across genders. Muscle mass loss-related information is more effective in generating negative attitude toward SSBs from males. Female image-related physical appearance change is more effective in generating negative attitude toward SSBs from females. This study also contributes to targeted communication by revealing that the quality-oriented targeted information outperformed the traditional quantity-oriented targeted information. Furthermore, this study complements EPPM by discovering the underlying mechanisms of female-targeted body image concern, such as perceived severity and response efficacy.

Mechanism of muscle atrophy in a normal-weight rat model of type 2 diabetes established by using a soft-pellet diet

Dietary factors such as food texture affect feeding behavior and energy metabolism, potentially causing obesity and type 2 diabetes. We previously found that rats fed soft pellets (SPs) were neither hyperphagic nor overweight but demonstrated glucose intolerance, insulin resistance, and hyperplasia of pancreatic β-cells. In the present study, we investigated the mechanism of muscle atrophy in rats that had been fed SPs on a 3-h time-restricted feeding schedule for 24 weeks. As expected, the SP rats were normal weight; however, they developed insulin resistance, glucose intolerance, and fat accumulation. In addition, skeletal muscles of SP rats were histologically atrophic and demonstrated disrupted insulin signaling. Furthermore, we learned that the muscle atrophy of the SP rats developed via the IL-6-STAT3-SOCS3 and ubiquitin-proteasome pathways. Our data show that the dietary habit of consuming soft foods can lead to not only glucose intolerance or insulin resistance but also muscle atrophy.

Sodium-glucose cotransporter 2 inhibitors influence skeletal muscle pathology in patients with heart failure and reduced ejection fraction

AIMS

Patients with heart failure and reduced ejection fraction (HFrEF) exhibit skeletal muscle pathology, which contributes to symptoms and decreased quality of life. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve clinical outcomes in HFrEF but their mechanism of action remains poorly understood. We aimed, therefore, to determine whether SGLT2i influence skeletal muscle pathology in patients with HFrEF.

METHODS AND RESULTS

Muscle biopsies from 28 male patients with HFrEF (New York Heart association class I-III) treated with SGLT2i (>12 months) or without SGLT2i were compared. Comprehensive analyses of muscle structure (immunohistochemistry), transcriptome (RNA sequencing), and metabolome (liquid chromatography-mass spectrometry) were performed, and serum inflammatory profiling (ELISA). Experiments in mice (n = 16) treated with SGLT2i were also performed. Myofiber atrophy was ~20% less in patients taking SGLT2i (p = 0.07). Transcriptomics and follow-up measures identified a unique signature in patients taking SGLT2i related to beneficial effects on atrophy, metabolism, and inflammation. Metabolomics identified influenced tryptophan metabolism in patients taking SGLT2i: kynurenic acid was 24% higher and kynurenine was 32% lower (p < 0.001). Serum profiling identified that SGLT2i treatment was associated with lower (p < 0.05) pro-inflammatory cytokines by 26-64% alongside downstream muscle interleukin (IL)-6-JAK/STAT3 signalling (p = 008 and 0.09). Serum IL-6 and muscle kynurenine were correlated (R = 0.65; p < 0.05). Muscle pathology was lower in mice treated with SGLT2i indicative of a conserved mammalian response to treatment.

CONCLUSIONS

Treatment with SGLT2i influenced skeletal muscle pathology in patients with HFrEF and was associated with anti-atrophic, anti-inflammatory, and pro-metabolic effects. These changes may be regulated via IL-6-kynurenine signalling. Together, clinical improvements following SGLT2i treatment in patients with HFrEF may be partly explained by their positive effects on skeletal muscle pathology.

Exploring Possible Links: Thigh Muscle Mass, Apolipoproteins, and Glucose Metabolism in Peripheral Artery Disease-Insights from a Pilot Sub-Study following Endovascular Treatment

Peripheral artery disease (PAD) compromises walking and physical activity, which results in further loss of skeletal muscle. The cross-sectional area of the thigh muscle has been shown to be correlated with systemic skeletal muscle volume. In our previous pilot study, we observed an increase in thigh muscle mass following endovascular treatment (EVT) in patients with proximal vascular lesions affecting the aortoiliac and femoropopliteal arteries. Considering the potential interactions between skeletal muscle, lipid profile, and glucose metabolism, we aimed to investigate the relationship between thigh muscle mass and apolipoproteins as well as glucose metabolism in PAD patients undergoing EVT. This study is a prespecified sub-study conducted as part of a pilot study. We prospectively enrolled 22 symptomatic patients with peripheral artery disease (PAD) and above-the-knee lesions, specifically involving the blood vessels supplying the thigh muscle. The mid-thigh muscle area was measured with computed tomography before and 6 months after undergoing EVT. Concurrently, we measured levels of apolipoproteins A1 (Apo A1) and B (Apo B), fasting blood glucose, 2 h post-load blood glucose (using a 75 g oral glucose tolerance test), and glycated hemoglobin A1c (HbA1c). Changes in thigh muscle area (delta muscle area: 2.5 ± 8.1 cm2) did not show significant correlations with changes in Apo A1, Apo B, fasting glucose, 2 h post-oral glucose tolerance test blood glucose, HbA1c, or Rutherford classification. However, among patients who experienced an increase in thigh muscle area following EVT (delta muscle area: 8.41 ± 5.93 cm2), there was a significant increase in Apo A1 (pre: 121.8 ± 15.1 mg/dL, 6 months: 136.5 ± 19.5 mg/dL, p < 0.001), while Apo B remained unchanged (pre: 76.4 ± 19.2 mg/dL, 6 months: 80.5 ± 4.9 mg/dL). Additionally, post-oral glucose tolerance test 2 h blood glucose levels showed a decrease (pre: 189.7 ± 67.5 mg/dL, 6 months: 170.6 ± 69.7 mg/dL, p = 0.075). Patients who exhibited an increase in thigh muscle area demonstrated more favorable metabolic changes compared to those with a decrease in thigh muscle area (delta muscle area: -4.67 ± 2.41 cm2). This pilot sub-study provides insights into the effects of EVT on thigh muscle, apolipoproteins, and glucose metabolism in patients with PAD and above-the-knee lesions. Further studies are warranted to validate these findings and establish their clinical significance. The trial was registered on the University Hospital Medical Information Network Clinical Trials Registry (UMIN000047534).

Breaking Down Cachexia: A Narrative Review on the Prevalence of Cachexia in Cancer Patients and Its Associated Risk Factors

Cachexia is an irreversible condition that involves a significant loss of body weight, muscle mass, and adipose tissue. It is a complex condition that involves a variety of metabolic, hormonal, and immune-related factors, with the precise mechanisms not yet fully understood. In this review, the prevalence of cachexia in different types of cancer as well as the potential risk factors was evaluated from literature retrieved from databases such as ScienceDirect, PubMed and Scopus. Potential risk factors evaluated here include tumor-related factors such as location, and stage of the cancer, as well as patient-related factors such as age, gender, and comorbidities. Several findings were observed where cachexia is more prevalent in male cancer patients than females, with higher incidences of weight loss and poorer outcomes. This may be due to the different muscle compositions between gender. Additionally, cachexia is more prevalent at the later stages, which may be brought about by the late-stage diagnosis of certain cancers. The anatomical location of certain cancers such as the pancreas and stomach may play a significant factor in their high prevalence of cachexia. These are sites of the synthesis of digestive enzymes and hormones regulating appetite. Cachexia is an issue faced by cancer patients which could affect their recovery. However, it is poorly understood, which limit therapeutic options. Hence, understanding this disease from different perspectives (clinical and pre-clinical), and bridging those findings could further improve our comprehension and consequently improve therapeutic options.

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

Co-Delivery of Bioengineered Exosomes and Oxygen for Treating Critical Limb Ischemia in Diabetic Mice

Diabetic patients with critical limb ischemia face a high rate of limb amputation. Regeneration of the vasculature and skeletal muscles can salvage diseased limbs. Therapy using stem cell-derived exosomes that contain multiple proangiogenic and promyogenic factors represents a promising strategy. Yet the therapeutic efficacy is not optimal because exosomes alone cannot efficiently rescue and recruit endothelial and skeletal muscle cells and restore their functions under hyperglycemic and ischemic conditions. To address these limitations, we fabricated ischemic-limb-targeting stem cell-derived exosomes and oxygen-releasing nanoparticles and codelivered them in order to recruit endothelial and skeletal muscle cells, improve cell survival under ischemia before vasculature is established, and restore cell morphogenic function under high glucose and ischemic conditions. The exosomes and oxygen-releasing nanoparticles, delivered by intravenous injection, specifically accumulated in the ischemic limbs. Following 4 weeks of delivery, the exosomes and released oxygen synergistically stimulated angiogenesis and muscle regeneration without inducing substantial inflammation and reactive oxygen species overproduction. Our work demonstrates that codelivery of exosomes and oxygen is a promising treatment solution for saving diabetic ischemic limbs.

WWP1 E3 ligase at the crossroads of health and disease

The E3 ubiquitin ligase WWP1 (WW Domain-containing E3 Ubiquitin Protein Ligase 1) is a member of the HECT (Homologous to the E6-associated protein Carboxyl Terminus) E3 ligase family. It is conserved across several species and plays crucial roles in various physiological processes, including development, cell growth and proliferation, apoptosis, and differentiation. It exerts its functions through ubiquitination or protein-protein interaction with PPXY-containing proteins. WWP1 plays a role in several human diseases, including cardiac conditions, neurodevelopmental, age-associated osteogenic disorders, infectious diseases, and cancers. In solid tumors, WWP1 plays a dual role as both an oncogene and a tumor suppressor, whereas in hematological malignancies such as AML, it is identified as a dedicated oncogene. Importantly, WWP1 inhibition using small molecule inhibitors such as Indole-3-Carbinol (I3C) and Bortezomib or siRNAs leads to significant suppression of cancer growth and healing of bone fractures, suggesting that WWP1 might serve as a potential therapeutic target for several diseases. In this review, we discuss the evolutionary perspective, structure, and functions of WWP1 and its multilevel regulation by various regulators. We also examine its emerging roles in cancer progression and its therapeutic potential. Finally, we highlight WWP1's role in normal physiology, contribution to pathological conditions, and therapeutic potential for cancer and other diseases.

Ultrasonographic Features of Muscular Weakness and Muscle Wasting in Critically Ill Patients

Muscle wasting begins as soon as in the first week of one's ICU stay and patients with multi-organ failure lose more muscle mass and suffer worse functional impairment as a consequence. Muscle wasting and weakness are mainly characterized by a generalized, bilateral lower limb weakness. However, the impairment of the respiratory and/or oropharyngeal muscles can also be observed with important consequences for one's ability to swallow and cough. Muscle wasting represents the result of the disequilibrium between breakdown and synthesis, with increased protein degradation relative to protein synthesis. It is worth noting that the resulting functional disability can last up to 5 years after discharge, and it has been estimated that up to 50% of patients are not able to return to work during the first year after ICU discharge. In recent years, ultrasound has played an increasing role in the evaluation of muscle. Indeed, ultrasound allows an objective evaluation of the cross-sectional area, the thickness of the muscle, and the echogenicity of the muscle. Furthermore, ultrasound can also estimate the thickening fraction of muscle. The objective of this review is to analyze the current understanding of the pathophysiology of acute skeletal muscle wasting and to describe the ultrasonographic features of normal muscle and muscle weakness.

Sodium-glucose co-transporter 2 inhibitors and Sarcopenia: A controversy that must be solved

Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest anti-hyperglycemic drugs. They reduce blood glucose levels by inhibiting renal glucose reabsorption in the early proximal convoluted tubule. Various randomized trials showed that SGLT2i have cardio-protective and reno-protective action. SGLT2i also affect body composition. They usually decrease body fat percentage, visceral and subcutaneous adipose tissue. However, regarding the muscle mass, there are conflicting findings some studies showing detrimental effects and others showed neutral or beneficial effects. This issue is extremely important not only because of the wide use of SGLT2i around globe; but also skeletal muscle mass consumes large amounts of calories during exercise and is an important determinant of resting metabolic rate and skeletal muscle loss hinders energy consumption leading to obesity. In this systematic review, we extensively reviewed the experimental and clinical studies regarding the impact of SGLT2i on muscle mass and related metabolic alterations. Importantly, studies are heterogeneous and there is unmet need to highlight the alterations in muscle during SGLT2i use.

Coordinated Regulation of Myonuclear DNA Methylation, mRNA, and miRNA Levels Associates With the Metabolic Response to Rapid Synergist Ablation-Induced Skeletal Muscle Hypertrophy in Female Mice

The central dogma of molecular biology dictates the general flow of molecular information from DNA that leads to a functional cellular outcome. In skeletal muscle fibers, the extent to which global myonuclear transcriptional alterations, accounting for epigenetic and post-transcriptional influences, contribute to an adaptive stress response is not clearly defined. In this investigation, we leveraged an integrated analysis of the myonucleus-specific DNA methylome and transcriptome, as well as myonuclear small RNA profiling to molecularly define the early phase of skeletal muscle fiber hypertrophy. The analysis of myonucleus-specific mature microRNA and other small RNA species provides new directions for exploring muscle adaptation and complemented the methylation and transcriptional information. Our integrated multi-omics interrogation revealed a coordinated myonuclear molecular landscape during muscle loading that coincides with an acute and rapid reduction of oxidative metabolism. This response may favor a biosynthesis-oriented metabolic program that supports rapid hypertrophic growth.

Salbutamol ameliorates skeletal muscle wasting and inflammatory markers in streptozotocin (STZ)-induced diabetic rats

Diabetes accelerates muscle atrophy, leading to the deterioration of skeletal muscles. This study aimed to assess the potential of the β2-adrenoceptor agonist, salbutamol (SLB), to alleviate muscle atrophy in streptozotocin (STZ)-induced diabetic rats. Male Sprague Dawley rats were randomized into four groups (n=6): control, SLB, STZ (55 mg/kg, single i.p.), and STZ + SLB (6 mg/kg, orally for 4 weeks). After the final SLB dose, animals underwent tests to evaluate muscle strength and coordination, including forelimb grip strength, wire-hanging, actophotometer, rotarod, and footprint assessments. Rats were then sacrificed, and serum and gastrocnemius (GN) muscles were collected for further analysis. Serum evaluations included proinflammatory markers (tumor necrosis factor α, interleukin-1β, interleukin-6), muscle markers (creatine kinase, myostatin), testosterone, and lipidemic markers. Muscle oxidative stress (malonaldehyde, protein carbonyl), antioxidants (glutathione, catalase, superoxide dismutase), and histology were also performed. Additionally, 1H nuclear magnetic resonance serum profiling was conducted. SLB notably enhanced muscle grip strength, coordination, and antioxidant levels, while reduced proinflammatory markers and oxidative stress in STZ-induced diabetic rats. Reduced serum muscle biomarkers, increased testosterone, restored lipidemic levels, and improved muscle cellular architecture indicated SLB's positive effect on muscle condition in diabetic rats. Metabolomics profiling revealed that the STZ group significantly increased the phenylalanine-to-tyrosine ratio (PTR), lactate-to-pyruvate ratio (LPR), acetate, succinate, isobutyrate, and histidine. SLB administration restored these perturbed serum metabolites in the STZ-induced diabetic group. In conclusion, salbutamol significantly protected against skeletal muscle wasting in STZ-induced diabetic rats.

Muscle Atrophy in CKD: A Historical Perspective of Advancements in Its Understanding

OBJECTIVE

This perspective reviews the seminal clinical and experimental observations that led to today's current mechanistic model of muscle protein loss (wasting) in patients with chronic kidney disease (CKD).

RESULTS AND CONCLUSION

Early International Society of Renal Nutrition and Metabolism (ISRNM) meetings facilitated discussions and hypotheses about the causes of muscle wasting in CKD. It became widely recognized that wasting is common and correlated with increased risks of mortality and morbidity. Although anorexia and dietary restrictions contribute to muscle loss, several features of CKD-associated wasting cannot be explained by malnutrition alone. The protein catabolism-inducing actions of metabolic acidosis, inflammation, insulin resistance, endocrine disorders and uremic toxins were progressively identified. Continued research to understand the interactions of inflammation, anabolic resistance, mitochondrial dysfunction, exercise, and nutrition on muscle protein turnover in patients with CKD will hopefully accelerate discoveries and treatments to ameliorate muscle wasting as well as the progression of CKD.

Association Between Autoimmune Diseases and Sarcopenia: A Two-Sample Mendelian Randomization Study

Purpose

Observational studies have reported that autoimmune diseases are closely related to sarcopenia, but the causalities of autoimmune diseases with sarcopenia have not been established. We conducted this Mendelian randomization (MR) study to reveal the causal associations of overall autoimmune disease and five common autoimmune diseases with sarcopenia-related traits.

Methods

The publicly available summary-level data of autoimmune diseases and three sarcopenia-related traits were used for analysis. The causal effects of autoimmune diseases on sarcopenia-related traits were first identified in discovery samples using the inverse-variance-weighted method as the primary method, and the robustness of results was examined by additional sensitivity analyses. Replication MR analyses were then conducted using replication samples of five autoimmune diseases. Finally, the possibility of reverse causation was assessed by reverse MR analyses.

Results

In both the discovery and replication samples, we identified potential causal effects of rheumatoid arthritis (RA) on appendicular lean mass (ALM) and low grip strength (OR = 0.979, 95% CI: 0.964-0.995 for ALM; OR = 1.042, 95% CI: 1.013-1.072 for low grip strength), but not on walking pace. We also found that inflammatory bowel disease (IBD) and type 1 diabetes (T1D) were only causally negatively associated with ALM in the discovery stage (OR = 0.986, 95% CI: 0.974-0.999 for IBD; OR = 0.987, 95% CI: 0.975-0.999 for T1D), whereas systemic lupus erythematosus, multiple sclerosis, and overall autoimmune disease were not associated with any of the three sarcopenia-related traits. Additionally, reverse MR analysis only found an association between walking pace and overall autoimmune disease, but this association did not remain in the weighted-median method.

Conclusion

This study demonstrates that RA is causally associated with low grip strength and reduced ALM, and that IBD and T1D may be causally negatively related to ALM.

A TGF-β/KLF10 signaling axis regulates atrophy-associated genes to induce muscle wasting in pancreatic cancer

Cancer cachexia, and its associated complications, represent a large and currently untreatable roadblock to effective cancer management. Many potential therapies have been proposed and tested-including appetite stimulants, targeted cytokine blockers, and nutritional supplementation-yet highly effective therapies are lacking. Innovative approaches to treating cancer cachexia are needed. Members of the Kruppel-like factor (KLF) family play wide-ranging and important roles in the development, maintenance, and metabolism of skeletal muscle. Within the KLF family, we identified KLF10 upregulation in a multitude of wasting contexts-including in pancreatic, lung, and colon cancer mouse models as well as in human patients. We subsequently interrogated loss-of-function of KLF10 as a potential strategy to mitigate cancer associated muscle wasting. In vivo studies leveraging orthotopic implantation of pancreas cancer cells into wild-type and KLF10 KO mice revealed significant preservation of lean mass and robust suppression of pro-atrophy muscle-specific ubiquitin ligases Trim63 and Fbxo32, as well as other factors implicated in atrophy, calcium signaling, and autophagy. Bioinformatics analyses identified Transforming growth factor beta (TGF-β), a known inducer of KLF10 and cachexia promoting factor, as a key upstream regulator of KLF10. We provide direct in vivo evidence that KLF10 KO mice are resistant to the atrophic effects of TGF-β. ChIP-based binding studies demonstrated direct binding to Trim63, a known wasting-associated atrogene. Taken together, we report a critical role for the TGF-β/KLF10 axis in the etiology of pancreatic cancer-associated muscle wasting and highlight the utility of targeting KLF10 as a strategy to prevent muscle wasting and limit cancer-associated cachexia.

Predictive value of glycemic gap and stress glycemia ratio among critically ill patients with acute kidney injury: a retrospective analysis of the MIMIC-III database

BACKGROUND AND AIMS

Acute hyperglycemia has been identified as a risk factor for acute kidney injury occurrence and mortality in various diseases. The aim of the current study was to investigate the relationship between stress-induced hyperglycemia and adverse outcomes in critically ill patients with AKI.

METHODS

We extracted clinical data from Multiparameter Intelligent Monitoring in Intensive Care III version 1.4. Blood glucose and glycosylated hemoglobin during the first 24 h of ICU admission were used to calculate glycemic gap and stress hyperglycemia ratio (SHR). The outcomes included ICU mortality and need for renal replacement therapy. The association of the glycemic gap and SHR with outcomes were determined via logistic regression model and receiver-operating curves. The subgroup analysis of patients with and without diabetes was performed separately.

RESULTS

Higher glycemic gap and SHR were observed in patients who had increased need of RRT, higher mortality rates and longer ICU stay. Multivariate analysis demonstrated that higher glycemic gap (OR 1.01, 95%CI 1.00-1.02, P = 0.015), as well as SHR (OR 1.32; 95%CI 1.07-1.64, P = 0.009), were independently associated with ICU mortality after adjusting for potential covariates. In subgroup analysis, the association of glycemic gap and SHR were only significant in the non-diabetic population as for the outcome of ICU mortality (OR 2.25, 95%CI 1.64-3.08, P < 0.001 and OR 1.99; 95%CI 1.46-2.72, P < 0.001, respectively).

CONCLUSIONS

The glycemic gap and SHR might serve as a potential prognostic indicator of ICU mortality in critically ill patients with AKI, especially in the non-diabetic population.

Relationship between frailty and methotrexate discontinuation due to adverse events in rheumatoid arthritis patients

INTRODUCTION

Methotrexate (MTX) is an anchor drug in the treatment of rheumatoid arthritis (RA). Frailty is the intermediate condition between being healthy and disabled, and can lead to negative health outcomes. Adverse events (AEs) due to RA drugs are expected to be higher in frail patients. The present study aimed to investigate the relationship between frailty and MTX discontinuation due to AEs in RA patients.

METHODS

Of 538 RA patients who visited us between June and August 2020 as part of the retrospective T-FLAG study, 323 used MTX. After 2 years of follow-up, we investigated AEs leading to MTX discontinuation. Frailty was defined as a Kihon Checklist (KCL) score ≥ 8. Cox proportional hazards regression analysis was performed to identify factors associated with MTX discontinuation due to AEs.

RESULTS

Of the 323 RA patients (251 women, 77.7%) who used MTX, 24 (7.4%) discontinued MTX due to AEs during the 2-year follow-up period. Mean ages in the MTX continuation/discontinuation groups were 64.5 ± 13.9/68.5 ± 11.7 years (p = 0.169), Clinical Disease Activity Index was 5.6 ± 7.3/6.2 ± 6.0 (p = 0.695); KCL was 5.9 ± 4.1/9.0 ± 4.9 points (p < 0.001); and the proportion of frailty was 31.8%/58.3% (p = 0.012). MTX discontinuation due to AEs was significantly associated with frailty (hazard ratio 2.34, 95% confidence interval 1.02-5.37) even after adjusting for age and diabetes mellitus. AEs included liver dysfunction (25.0%), pneumonia (20.8%), and renal dysfunction (12.5%).

CONCLUSIONS

Because frailty is a significant factor contributing to MTX discontinuation due to AEs, the latter should be carefully monitored in frail RA patients who use MTX. Key Points • Of the 323 rheumatoid arthritis (RA) patients (251 women, 77.7%) who used methotrexate (MTX), 24 (7.4%) discontinued MTX due to adverse events (AEs) during the 2-year follow-up period. • MTX discontinuation due to AEs was significantly associated with frailty (hazard ratio 2.34, 95% confidence interval 1.02-5.37) even after adjusting for age and diabetes mellitus, and neither the MTX dose, folic acid supplementation, nor GC co-therapy were factors in MTX discontinuation. • Frailty is a predominant factor in MTX discontinuation among established, long-term pretreated RA patients, and the occurrence of AEs due to MTX should be carefully monitored when frail RA patients use MTX.

Diet, exercise, and pharmacotherapy for sarcopenia in people with diabetes

Diabetes prevalence is increasing rapidly in older people, and sarcopenia is prevalent as a novel complication, particularly in patients with type 2 diabetes mellitus (T2DM). Therefore, sarcopenia prevention and treatment in these people is necessary. Diabetes accelerates sarcopenia through several mechanisms, such as hyperglycemia, chronic inflammation and oxidative stress. The effects of diet, exercise, and pharmacotherapy on sarcopenia in patients with T2DM need to be considered. In diet, low intake of energy, protein, vitamin D, and ω-3 fatty acid are associated with sarcopenia risk. In exercises, although intervention studies in people, especially older and non-obese patients with diabetes, are few, accumulating evidence shows the usefulness of exercise, particularly resistance exercise for muscle mass and strength, and aerobic exercise for physical performance in sarcopenia. In pharmacotherapy, certain classes of anti-diabetes compounds have possibility of preventing sarcopenia. However, much data on diet, exercise, and pharmacotherapy were obtained in obese and non-elderly patients with T2DM, demanding actual clinical data on non-obese and older patients with diabetes.

Integration of nutrigenomics, melatonin, serotonin and inflammatory cytokines in the pathophysiology of pregnancy-specific urinary incontinence in women with gestational diabetes mellitus

Gestational diabetes mellitus is an important public health problem and has been associated with the development of pregnancy-specific urinary incontinence. The interaction is related to hyperglycemia, and inflammatory and hormonal patterns, which favor functional alterations in different organs and systems. Several genes associated with human diseases have been identified and partially characterized. Most of these genes are known to cause monogenic diseases. However, about 3 % of diseases do not fit the monogenic theory due to the complex interactions between multiple genes and environmental factors, as in chronic metabolic diseases such as diabetes. The nutritional, immunological, and hormonal patterns associated with changes in maternal metabolism may influence and contribute to greater susceptibility to urinary tract disorders. However, early systematic reviews have not yielded consistent findings for these associations. This literature review summarizes important new findings from integrating nutrigenomics, hormones, and cytokines in women with Gestational diabetes mellitus and pregnancy-specific urinary incontinence. Changes in maternal metabolism due to hyperglycemia can generate an inflammatory environment with increased inflammatory cytokines. This environment modulated by inflammation can alter tryptophan uptake through food and thus influence the production of serotonin and melatonin. As these hormones seem to have protective effects against smooth muscle dysfunction and to restore the impaired contractility of the detrusor muscle, it is assumed that these changes may favor the onset of urinary incontinence specific to pregnancy.

Effects of luseogliflozin treatment on hyperglycemia-induced muscle atrophy in rats

Diabetes mellitus is recognized as a risk factor for sarcopenia. Luseogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, reduces inflammation and oxidative stress by improving hyperglycemia, subsequently improving hepatosteatosis or kidney dysfunction. However, the effects of SGLT2 inhibitor on the regulation of skeletal muscle mass or function in hyperglycemia are still unknown. In this study, we investigated the effects of luseogliflozin-mediated attenuation of hyperglycemia on the prevention of muscle atrophy. Twenty-four male Sprague-Dawley rats were randomly divided into four groups: control, control with SGLT2 inhibitor treatment, hyperglycemia, and hyperglycemia with SGLT2 inhibitor treatment. The hyperglycemic rodent model was established using a single injection of streptozotocin, a compound with preferential toxicity toward pancreatic beta cells. Muscle atrophy in streptozotocin-induced hyperglycemic model rats was inhibited by the suppression of hyperglycemia using luseogliflozin, which consequently suppressed hyperglycemia-mediated increase in the levels of advanced glycation end products (AGEs) and activated the protein degradation pathway in muscle cells. Treatment with luseogliflozin can restore the hyperglycemia-induced loss in the muscle mass to some degree partly through the inhibition of AGEs-induced or homeostatic disruption of mitochondria-induced activation of muscle degradation.