The sodium-glucose cotransporter 2 inhibitor luseogliflozin can suppress muscle atrophy in Db/Db mice by suppressing the expression of foxo1

Effects of Sodium-Glucose Cotransporter 2 Inhibitors on Transcription Regulation of AgRP and POMC Genes

Sodium-glucose cotransporter 2 (SGLT2) inhibitors regulate plasma glucose levels in patients with type 2 diabetes mellitus (T2DM) by inhibiting renal glucose reabsorption. This study investigated the impact of empagliflozin (EMPA), an SGLT2 inhibitor, on hypothalamic energy regulation. To directly investigate the role of SGLT2 inhibitors in the hypothalamus, we administered EMPA through intracerebroventricular (i.c.v.) injections into the murine ventricles. After dental cementing the i.c.v. cannula onto the skull, the mice were given 5 days to recover before receiving vehicle or EMPA (50 nM/2 μL) injections. In a high-fat diet (HFD)-induced obesity model, we determined the gene expression levels of agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) in the hypothalamus. Additionally, we assessed FoxO1 expression, which regulates AgRP and POMC gene transcription in hypothalamic cell lines. We found that EMPA directly influenced the expression of endogenous mRNA of POMC and AgRP, which are critical for energy homeostasis, and modulated their transcription in high-fat diet-induced obese mice. Additionally, EMPA affected the expression of FoxO1, a key transcriptional regulator of glucose homeostasis, thereby regulating the transcriptional activity of POMC and AgRP. These results indicate that EMPA significantly influences hypothalamic energy homeostasis, highlighting its potential as a regulator in obesity and T2DM management.

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.

Miso, fermented soybean paste, suppresses high-fat/high-sucrose diet-induced muscle atrophy in mice

This study investigated the effects of miso, a traditional fermented soybean food in Japan, on muscle mass atrophy. Eight week old male C57BL/6J mice were fed high fat/high sucrose diet with or without miso for 12 weeks. A miso diet increased soleus muscle weights (p<0.05) and reduced intraperitoneal glucose tolerance and insulin tolerance (p<0.05). The miso diet downregulated the Tnfα and Ccl2 expression, related to inflammation, and Trim63 and Fbxo32 expression, related to muscle atrophy, in the soleus muscle (p<0.05). The miso diet increased short-chain fatty acids levels, including acetic, propanoic, and butanoic acids, in the feces, serum, and soleus muscle (p<0.05). According to the LEfSe analysis, the miso diet increased family Prevotellaceae, family Christensenellaceae, family Dehalobacterium, family Desulfitibacter; family Deferribacteraceae, order Deferribacterales, class Deferribacteres; and family Gemmatimonadaceae, order Gemmatimonadetes, and class Gemmatimonadales, whereas the miso diet decreased family Microbacteriaceae, order Micrococcales, class Actinobacteria, and family Lactobacillaceae. Miso suppressed high fat/high sucrose diet induced impaired glucose tolerance, low muscle strength, and muscle atrophy by improving dysbiosis and increasing short-chain fatty acids production and provides new insights into the preventive effects of fermented foods on sarcopenia.

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.

The role of chicken eggs in modulating sarcopenic obesity and gut microbiota in db/db mice

Background

Sarcopenia obesity, in which loss of muscle mass and fat accumulation occur simultaneously, is the pathological basis of type 2 diabetes mellitus. The usefulness of chicken eggs in sarcopenia prevention has been reported in several previous studies. The purpose of this study was to determine the beneficial effects of chicken eggs in the prevention of sarcopenic obesity in db/db mice.

Methods

We raised 8-week-old db/db male mice, a model of sarcopenia obesity, for 8 weeks and fed them a diet mixed with dried whole eggs. The fecal microbiota transplant (FMT) group was treated with antibiotics for 2 weeks, starting at 6 weeks of age, followed by FMT twice a week until 16 weeks of age.

Results

Eggs administered to db/db mice showed increased grip strength (p = 0.022) and muscle mass (p = 0.013), decreased visceral fat mass (p = 0.005), and significantly increased physical activity (p < 0.001). The FMT group of egg-fed mice showed a significant improvement in glucose intolerance and sarcopenic obesity. Sequencing of gene expression in the small intestine showed that the gene expression of amino acid transporters such as Slc6a18, Slc6a19, and Slc38a6 was increased in egg-fed mice. 16S rRNA sequencing of the gut microbiota showed an increase in the genus Vampirovibrio in both the egg-fed and FMT groups compared to that in egg-fed mice.

Conclusion

The results of this study indicate that egg consumption not only increases the intake of amino acids and other nutrients but also alters the intestinal microbiota and increases amino acid absorption from the intestinal tract, suggesting that eggs might contribute to the ameliorative mechanism of sarcopenic obesity.

RNA-Seq transcriptomic landscape profiling of spontaneously hypertensive rats treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor

BACKGROUND

Sodium-glucose co-transporter-2 inhibitor (SGLT2i) are antihyperglycemic medications that reduce cardiovascular disease (CVD) and improve chronic kidney disease prognosis in patients with diabetes mellitus. The specific impact of SGLT2i treatment on hypertensive individuals, however, remains to be established. This underscores the need for systematic efforts to profile the molecular landscape associated with SGLT2i administration.

METHODS

We conducted a detailed RNA-sequencing (RNA-Seq)-based exploration of transcriptomic changes in response to empagliflozin in eight different tissues (i.e., atrium, aorta, ventricle, white adipose, brown adipose, kidney, lung, and brain) from a male rat model of spontaneously hypertension. Corresponding computational analyses (i.e., clustering, differentially-expressed genes [DEG], and functional association) were performed to analyze these data. Blood pressure measurements, tissue staining studies and RT-qPCR were performed to validate our in silico findings.

RESULTS

We discovered that empagliflozin exerted potent transcriptomic effects on various tissues, most notably the kidney, white adipose, and lung in spontaneously hypertension rats (SHR). The functional enrichment of DEGs indicated that empagliflozin may regulate blood pressure, blood glucose and lipid homeostasis in SHR. Consistent with our RNA-Seq findings, immunohistochemistry and qPCR analyses revealed decreased renal expression of mitogen-activated protein kinase 10 (MAPK10) and decreased pulmonary expression of the proinflammatory factors Legumain and cathepsin S (CTSS) at 1 month of empagliflozin administration. Notably, immunofluorescence experiments showed increased expression of the AMP-activated protein kinases Prkaa1 and Prkaa2 in white adipose tissue of SHR following empagliflozin therapy. Furthermore, the transcriptomic signatures of the blood pressure-lowing effect by empagliflozin were experimentally validated in SHR.

CONCLUSIONS

This study provided an important resource of the effects of empagliflozin on various tissues of SHRs. We identified tissue-specific and tissue-enriched transcriptomic signatures, and uncovered the beneficial effects of empagliflozin on hypertension, weight gain and inflammatory response in validated experiments.

Exercise mitigates Dapagliflozin-induced skeletal muscle atrophy in STZ-induced diabetic rats

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are commonly used in the management of type 2 diabetes mellitus (T2DM) and have been found to worsen the reduction of skeletal muscle mass in individuals with T2DM. This study aims to examine the potential of exercise in mitigating the skeletal muscle atrophy induced by SGLT2i treatment.

METHODS

A rat model of T2DM (40 male Sprague-Dawley rats; T2DM induced by a combination of high-fat diet and streptozotocin) was used to examine the effects of six-week treatment with Dapagliflozin (DAPA, SGLT2i) in combination with either aerobic exercise (AE) or resistance training (RT) on skeletal muscle. T2DM-eligible rats were randomized into the T2DM control group (CON, n = 6), DAPA treatment group (DAPA, n = 6), DAPA combined with aerobic exercise intervention group (DAPA + AE, n = 6), and DAPA combined with resistance training intervention group (DAPA + RT, n = 6). To assess the morphological changes in skeletal muscle, myosin ATPase and HE staining were performed. mRNA expression levels of Atrogin-1, MuRF1, and Myostatin were determined using quantitative PCR. Furthermore, protein expression levels of AKT, p70S6K, mTOR, FoXO1/3A, NF-κB, and MuRF1 were examined through western blotting.

RESULTS

Both the administration of DAPA alone and the combined exercise intervention with DAPA resulted in significant reductions in blood glucose levels and body weight in rats. However, DAPA alone administration led to a decrease in skeletal muscle mass, whereas RT significantly increased skeletal muscle mass and muscle fiber cross-sectional area. The DAPA + RT group exhibited notable increases in both total protein levels and phosphorylation levels of AKT and p70S6K in skeletal muscle. Moreover, the DAPA, DAPA + AE, and DAPA + RT groups demonstrated downregulation of protein expression (FoXO1/3A) and mRNA levels (Atrogin-1, MuRF1, and Myostatin) associated with muscle atrophy.

CONCLUSIONS

Our findings provide support for the notion that dapagliflozin may induce skeletal muscle atrophy through mechanisms unrelated to protein metabolism impairment in skeletal muscle, as it does not hinder protein metabolic pathways while reduces muscle atrophy-related genes. Additionally, our observations reveal that RT proves more effective than AE in enhancing skeletal muscle mass and muscle fiber cross-sectional area in rats with T2DM by stimulating protein anabolism within the skeletal muscle.

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.

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.

Kcnma1 is involved in mitochondrial homeostasis in diabetes-related skeletal muscle atrophy

Uncontrolled diabetes causes a catabolic state with multi-organic complications, of which impairment on skeletal muscle contributes to the damaged mobility. Kcnma1 gene encodes the pore-forming α-subunit of Ca²⁺ - and voltage-gated K⁺ channels of large conductance (BK channels), and loss-of-function mutations in Kcnma1 are in regards to impaired myogenesis. Herein, we observed a time-course reduction of Kcnma1 expression in the tibialis anterior muscles of leptin receptor-deficient (db/db) diabetic mice. To investigate the role of Kcnma1 in diabetic muscle atrophy, muscle-specific knockdown of Kcnma1 was achieved by mice receiving intravenous injection of adeno-associated virus-9 (AAV9)-encoding shRNA against Kcnma1 under the muscle creatine kinase (MCK) promoter. Impairment on muscle mass and myogenesis were observed in m/m mice with AAV9-shKcnma1 intervention, while this impairment was more obvious in diabetic db/db mice. Simultaneously, damaged mitochondrial dynamics and biogenesis showed much severer in db/db mice with AAV9-shKcnma1 intervention. RNA sequencing revealed the large transcriptomic changes resulted by Kcnma1 knockdown, and changes in mitochondrial homeostasis-related genes were validated. Besides, the artificial alteration of Kcnma1 in mouse C2C12 myoblasts was achieved with an adenovirus vector. Consistent results were demonstrated by Kcnma1 knockdown in palmitate-treated cells, whereas opposite results were exhibited by Kcnma1 overexpression. Collectively, we document Kcnma1 as a potential keeper of mitochondrial homeostasis, and the loss of Kcnma1 is a critical event in priming skeletal muscle loss in diabetes.

Empagliflozin Preserves Skeletal Muscle Function in a HFpEF Rat Model

Besides structural alterations in the myocardium, heart failure with preserved ejection fraction (HFpEF) is also associated with molecular and physiological alterations of the peripheral skeletal muscles (SKM) contributing to exercise intolerance often seen in HFpEF patients. Recently, the use of Sodium-Glucose-Transporter 2 inhibitors (SGLT2i) in clinical studies provided evidence for a significant reduction in the combined risk of cardiovascular death or hospitalization for HFpEF. The present study aimed to further elucidate the impact of Empagliflozin (Empa) on: (1) SKM function and metabolism and (2) mitochondrial function in an established HFpEF rat model. At the age of 24 weeks, obese ZSF1 rats were randomized either receiving standard care or Empa in the drinking water. ZSF1 lean animals served as healthy controls. After 8 weeks of treatment, echocardiography and SKM contractility were performed. Mitochondrial function was assessed in saponin skinned fibers and SKM tissue was snap frozen for molecular analyses. HFpEF was evident in the obese animals when compared to lean—increased E/é and preserved left ventricular ejection fraction. Empa treatment significantly improved E/é and resulted in improved SKM contractility with reduced intramuscular lipid content. Better mitochondrial function (mainly in complex IV) with only minor modulation of atrophy-related proteins was seen after Empa treatment. The results clearly documented a beneficial effect of Empa on SKM function in the present HFpEF model. These effects were accompanied by positive effects on mitochondrial function possibly modulating SKM function.

Gut Microbiota Changes by an SGLT2 Inhibitor, Luseogliflozin, Alters Metabolites Compared with Those in a Low Carbohydrate Diet in db/db Mice

In recent years, sarcopenic obesity has been considered central pathological factors in diabetes. This study aimed to compare the effect of luseogliflozin, a sodium-glucose co-transporter-2 inhibitor (SGLT2i), on sarcopenic obesity in comparison to that of a low-carbohydrate diet (LCD). Twenty-week-old male db/db mice were fed a normal diet (Ctrl), LCD, and normal diet with 0.01% w/w luseogliflozin (SGLT2i) for eight weeks. Skeletal muscle mass and grip strength decreased in the LCD group mice compared to those in the control group, while they increased in the SGLT2i group mice. The amino acid content in the liver, skeletal muscle, and serum were lower in the LCD group than those in the Ctrl group but increased in the SGLT2i group mice. Short-chain fatty acids in rectal feces were lower in the LCD group mice than those in the Ctrl group, whereas they were higher in the SGLT2i group mice. The abundance of Gammaproteobacteria, Enterobacteriaceae, Escherichia, Enterobacterales, and Bacteroides caccae species increased in the LCD group compared to the other two groups, whereas the abundance of Syntrophothermus lipocalidus, Syntrophomonadaceae family, Parabacteroidesdistasonis distasonis, and the genus Anaerotignum increased in the SGLT2i group. Luseogliflozin could prevent sarcopenic obesity by improving amino acid metabolism.

Could SGLT2 Inhibitors Improve Exercise Intolerance in Chronic Heart Failure?

Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed.

Relationship Between Dietary Omega-3 and Omega-6 Polyunsaturated Fatty Acids Level and Sarcopenia. A Meta-Analysis of Observational Studies

Objective: This study investigates the relationship between dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) levels and sarcopenia.

Methods: A comprehensive literature search in the databases of PubMed, Web of Science, and Embase (up to July 2021) were conducted to identify the observational studies on the relationship between dietary omega-3 and omega-6 PUFAs level and sarcopenia. The pooled odds ratio (OR) of sarcopenia for the highest vs. lowest dietary omega-3 and omega-6 PUFAs level and the standard mean difference (SMD) of dietary omega-3 and omega-6 PUFAs levels for sarcopenia vs. control subjects were calculated.

Results: A total of six studies were identified in this meta-analysis. The overall multi-variable adjusted OR showed that dietary omega-3 PUFAs level was inversely associated with sarcopenia (OR = 0.41, 95% CI: 0.26–0.65; P = 0.0001). Moreover, the overall combined SMD showed that the dietary omega-3 PUFAs level in sarcopenia was lower than that in control subjects (SMD = −0.19, 95% CI: −0.32 to −0.07; P = 0.002). With regard to dietary omega-6 PUFAs level, the overall multi-variable adjusted OR suggested no significant relationship between dietary omega-6 PUFAs level and sarcopenia (OR = 0.64, 95% CI: 0.33–1.24; P = 0.19). However, the overall combined SMD showed that the dietary omega-6 PUFAs level in sarcopenia was slightly lower than that in control subjects (SMD = −0.15, 95% CI: −0.27 to −0.02; P = 0.02).

Conclusion: Our results suggested that the dietary omega-3 PUFAs level was inversely associated with sarcopenia. However, current evidence is still insufficient to demonstrate the definite relationship between dietary omega-6 PUFAs levels and sarcopenia. More well-designed prospective cohort studies with the dietary omega-3/omega-6 PUFAs ratio are still needed.

Extracellular lipidome change by an SGLT2 inhibitor, luseogliflozin, contributes to prevent skeletal muscle atrophy in db/db mice

BACKGROUND

Diabetes mellitus increases the excretion of urinary glucose from the renal glomeruli due to elevated blood glucose levels. In the renal tubules, SGLT2 is expressed and reabsorbs the excreted urinary glucose. In the pathogenesis of diabetes mellitus, glucose reabsorption by SGLT2 is increased, and SGLT2 inhibitors improve hyperglycaemia by inhibiting this reabsorption. When urinary glucose excretion is enhanced, glucose supply to skeletal muscle may be insufficient and muscle protein catabolism may be accelerated. On the other hand, SGLT2 inhibitors not only ameliorate hyperglycaemia but also improve fatty acid metabolism in muscle, which may prevent muscle atrophy.

METHODS

Eight-week-old male db/m mice or db/db mice were fed a standard diet with or without the SGLT2i luseogliflozin (0.01% w/w in chow) for 8 weeks. Mice were sacrificed at 16 weeks of age, and skeletal muscle and serum lipidomes, as well as skeletal muscle transcriptome, were analysed.

RESULTS

Administration of SGLT2i led to not only decreased visceral fat accumulation (P = 0.004) but also increased soleus muscle weight (P = 0.010) and grip strength (P = 0.0001). The levels of saturated fatty acids, especially palmitic acid, decreased in both muscles (P = 0.017) and sera (P = 0.041) upon administration of SGLT2i, while the content of monosaturated fatty acids, especially oleic acid, increased in both muscle (P < 0.0001) and sera (P = 0.009). Finally, the accumulation of transcripts associated with fatty acid metabolism, such as Scd1, Fasn, and Elovl6, and of muscle atrophy-associated transcripts, such as Foxo1, Mstn, Trim63, and Fbxo32, decreased following SGLT2i administration.

CONCLUSIONS

Intramuscular fatty acid metabolism and gene expression were influenced by the extracellular lipidome, which was modified by SGLT2i. Hence, secondary effects, other than the hypoglycaemic effects of SGLT2i, might lead to the alleviation of sarcopenia.

Effects of anti-diabetic drugs on sarcopenia: Best treatment options for elderly patients with type 2 diabetes mellitus and sarcopenia

Human life expectancy increases as society becomes more developed. This increased life expectancy poses challenges associated with the rapid aging of the population. Sarcopenia, an age-related disease, has become a worldwide health issue. Patients with sarcopenia experience decreases in muscle mass and function, becoming frail and eventually bedridden. Type 2 diabetes mellitus (T2DM) is also a major health issue; the incidence of T2DM increases with aging. T2DM is associated with reduced muscle strength and poor muscle quality and may contribute to acceleration of the aging process, augmenting age-related sarcopenia. Recent studies indicate that elderly patients with diabetes are at an increased risk for sarcopenia. Therefore, these older diabetic patients with sarcopenia need specific anti-diabetic therapies targeting not only glycemic control but also sarcopenia, with the goal of preventing sarcopenia in pre-sarcopenic patients. Presently, various types of hypoglycemic drugs are available, but which hypoglycemic drugs are better suited for geriatric T2DM patients with sarcopenia remains undetermined. In this review, we discuss the association between diabetes and sarcopenia in geriatric patients, and how anti-diabetic drugs may influence sarcopenia outcomes. This review will guide clinical workers in the selection of drugs best suited for this patient population.

Sarcopenia Is Associated With a Risk of Mortality in People With Type 2 Diabetes Mellitus

BACKGROUND

Sarcopenia has reportedly been associated with increased risk of mortality in general populations. However, few studies have investigated the association between sarcopenia and mortality in older people with type 2 diabetes mellitus (T2D). This study aimed to investigate the effect of sarcopenia on incident all-cause mortality in older people with T2D.

METHODS

Low muscle strength were set at handgrip strength <28 kg for men and <18 kg for women, and low skeletal muscle mass index (SMI), evaluated using the impedance body composition analyzer, were set at SMI <7.0 kg/m² for men and <5.7 kg/m² for women. People who had both low muscle strength and low SMI were diagnosed with sarcopenia. Due to a low incidence of all-cause mortality, the propensity score was used. The propensity score was evaluated using multivariable logistic regression models with the following parameters: age, sex, duration of diabetes, history of heart disease, history of cancer, smoking, exercise, alcohol, sodium-glucose cotransporter-2 inhibitor, glucagon-like peptide-1 receptor agonist, insulin, corticosteroid, hypertension, body mass index, glycosylated hemoglobin A1c, triglycerides, and creatinine, and the C-statistic was 0.89.

RESULTS

In this prospective cohort study, 396 people with an average age and duration of diabetes of 71.3 (6.3) years and 16.3 (11.3) years, respectively, were included. Of those included, 14.6% had sarcopenia. During the average 40.5 (16.5) months of follow-up, 13 people (6 out of the 338 without sarcopenia and 7 out of the 58 with sarcopenia) died. Incident rate were 5.1/1000 person years of follow-up in people without sarcopenia and 41.3/1000 person years of follow-up in people with sarcopenia. According to Cox regression analysis, sarcopenia was associated with all-cause mortality (adjusted hazard ratio: 6.12, 95% confidence interval: 1.52-24.7, p = 0.011).

CONCLUSION

Sarcopenia is associated with incident all-cause mortality in older outpatients with T2D.

ALDH2 mutation promotes skeletal muscle atrophy in mice via accumulation of oxidative stress

Muscle atrophy is promoted by various factors including aging, immobilization, unloading and use of drugs such as steroids. However, genetic risk factors for muscle atrophy are less well known. Here, we show that a missense SNP in the ALDH2 gene, rs671 (ALDH2*2), a dominant negative mutation, promotes significant muscle atrophy in the ALDH2*2 mouse model, accompanied by decreased expression of anabolic and catabolic muscle factors and acquisition of a low turnover state. We also demonstrate that expression of LC3, which is require for auto-phagosome formation during autophagy, increases in ALDH2*2 mouse muscles. We show that 4-hydroxynonenal (4HNE), a peroxidated lipid-protein and oxidant, accumulates in ALDH2*2 mouse muscles. We have shown that the rs671 mutation is associated with increased serum levels of acetaldehyde, an alcohol metabolite. We show that expression of the atrogenes Atrogin1 and MuRF1 significantly increased in myogenic cells following acetaldehyde treatment, an outcome significantly inhibited in vitro by Trolox C, an anti-oxidant. Muscle atrophy in ALDH2*2 mice was also significantly rescued by dietary administration of the anti-oxidant vitamin E, which blocked 4HNE accumulation in muscle. Taken together, our data indicate that rs671 is a genetic risk factor for muscle atrophy, but that such atrophy can be rescued by vitamin E treatment.

Comparison of dapagliflozin and teneligliptin in nonalcoholic fatty liver disease patients without type 2 diabetes mellitus: a prospective randomized study

There are no reports regarding the efficacy of sodium-glucose cotransporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase 4 inhibitor (DPP4i) administrations in nonalcoholic fatty liver disease (NAFLD) patients without type 2 diabetes mellitus. The purpose of this study was to evaluate the efficacy of those drugs in such patients. NAFLD patients without type 2 diabetes mellitus were enrolled in this single center double-blind randomized prospective study, and allocated to receive either dapagliflozin (SGLT2i) or teneligliptin (DPP4i) for 12 weeks. Laboratory variables and body compositions were assessed at the baseline and end of treatment. The primary endpoint was alanine aminotransferase (ALT) reduction level at the end of treatment. Twenty-two eligible patients (dapagliflozin group, n = 12; teneligliptin group, n = 10) were analyzed. In both groups, the serum concentration of ALT was significantly decreased after treatment (p<0.05). Multiple regression analysis results showed that decreased body weight of patients with dapagliflozin administration was significantly related to changes in total body water and body fat mass. Administration of dapagliflozin or teneligliptin decreased the serum concentration of ALT in NAFLD patients without type 2 diabetes mellitus. With dapagliflozin, body weight decreased, which was related to changes in total body water and body fat mass (UMIN000027304).

Reduction of stearoyl-CoA desaturase (SCD) contributes muscle atrophy through the excess endoplasmic reticulum stress in chronic kidney disease

Skeletal muscle atrophy is associated with mortality and poor prognosis in patients with chronic kidney disease (CKD). However, underlying mechanism by which CKD causes muscle atrophy has not been completely understood. The quality of lipids (lipoquality), which is defined as the functional features of diverse lipid species, has recently been recognized as the pathology of various diseases. In this study, we investigated the roles of the stearoyl-CoA desaturase (SCD), which catalyzes the conversion of saturated fatty acids into monounsaturated fatty acids, in skeletal muscle on muscle atrophy in CKD model animals. In comparison to control rats, CKD rats decreased the SCD activity and its gene expression in atrophic gastrocnemius muscle. Next, oleic acid blocked the reduction of the thickness of C2C12 myotubes and the increase of the endoplasmic reticulum stress induced by SCD inhibitor. Furthermore, endoplasmic reticulum stress inhibitor ameliorated CKD-induced muscle atrophy (the weakness of grip strength and the decrease of muscle fiber size of gastrocnemius muscle) in mice and the reduction of the thickness of C2C12 myotubes by SCD inhibitor. These results suggest that the repression of SCD activity causes muscle atrophy through excessive endoplasmic reticulum stress in CKD.

Reduced dietary omega-3 fatty acids intake is associated with sarcopenia in elderly patients with type 2 diabetes: a cross-sectional study of KAMOGAWA-DM cohort study

Omega-3 fatty acids intake is important to maintain muscle mass. However, the relationship between omega-3 fatty acids intake and sarcopenia in elderly patients with type 2 diabetes has been unclear. We used the brief-type self-administered diet history questionnaire for the assessment of habitual food and nutrient intake. Body composition of patients was evaluated using bioimpedance analysis. To investigate the effect of energy intake on the presence of sarcopenia, we performed logistic regression analyses. Among the patients, 45 patients (13.2%) were diagnosed as sarcopenia. Patients with sarcopenia were aged [74.2 (5.7) vs 71.4 (5.9) years, p = 0.003] and lower body mass index [21.2 (3.5) vs 24.3 (4.6) kg/m², p<0.001] than those without. In addition, omega-3 fatty acids intake of patients with sarcopenia was lower than that without [2.6 (1.0) vs 3.0 (1.2) kcal/day, p = 0.046]. Omega-3 fatty acids intake was negatively associated with the presence of sarcopenia (odds ratio: 0.29, 95% confidence interval: 0.14-0.60, p<0.001) after adjusting for age, sex, exercise, smoking status, diabetes duration, hemoglobin A1c, energy intake, protein intake, fat intake and omega-3 fatty acids intake. Omega-3 fatty acids intake was negatively associated with the presence of sarcopenia in elderly patients with type 2 diabetes.

Japanese radio calisthenics prevents the reduction of skeletal muscle mass volume in people with type 2 diabetes

OBJECTIVE

Reduction of muscle mass and strength is an important treatment target for patients with type 2 diabetes. Recent studies have reported that high-intensity resistance training improves physical function; however, all patients found it difficult to perform high-intensity resistance training. Radio calisthenics, considered as therapeutic exercises to promote health in Japan, are simple exercises that can be performed regardless of age and help move the muscles and joints of the whole body effectively according to the rhythm of radio. We investigated the efficacy of radio calisthenics for muscle mass in patients with type 2 diabetes in this retrospective cohort study.

RESEARCH DESIGN AND METHODS

A total of 42 hospitalized patients with type 2 diabetes were recruited. The skeletal muscle mass index (SMI, kg/m²) was calculated as appendicular muscle mass (kg) divided by height squared (m²). We defined the change of SMI as the difference of SMI between the beginning and end of hospitalization.

RESULTS

Among 42 patients, 15 (11 men and 4 women) performed radio calisthenics. Body weights of both radio calisthenics exercisers and non-exercisers decreased during hospitalization. The change of SMI was significantly lesser in radio calisthenics exercisers than in non-exercisers (7.1±1.4 to 7.1±1.3, -0.01±0.09 vs 6.8±1.1 to 6.5±1.2, -0.27±0.06 kg/m², p=0.016). The proportion of decreased SMI was 85.2% (23/27 patients) in non-radio calisthenics exercisers, whereas that in radio calisthenics exercisers was 46.7% (7/15 patients).

CONCLUSIONS

Radio calisthenics prevent the reduction of skeletal muscle mass. Thus, radio calisthenics can be considered effective for patients with type 2 diabetes.