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New Findings What is the central question of this study? Our aim was to examine whether sesamin can prevent a decline in exercise capacity in high-fat diet-induced diabetic mice. Our hypothesis was that maintenance of mitochondrial function and attenuation of oxidative stress in the skeletal muscle would contribute to this result., What is the main finding and its importance? The new findings are that sesamin prevents the diabetes-induced decrease in exercise capacity and impairment of mitochondrial function through the inhibition of NAD(P)H oxidase-dependent oxidative stress in the skeletal muscle. Sesamin may be useful as a novel agent for the treatment of diabetes mellitus., Abstract We previously reported that exercise capacity and skeletal muscle mitochondrial function in diabetic mice were impaired, in association with the activation of NAD(P)H oxidase. It has been reported that sesamin inhibits NAD(P)H oxidase-induced superoxide production. Therefore, we examined whether the antioxidant sesamin could prevent a decline in exercise capacity in mice with high-fat diet (HFD)-induced diabetes. C57BL/6J mice were fed a normal diet (ND) or HFD, then treated or not with sesamin (0.2%) to yield the following four groups: ND, ND+Sesamin, HFD and HFD+Sesamin ( n = 10 each). After 8 weeks, body weight, fat weight, blood glucose, insulin, triglyceride, total cholesterol and fatty acid were significantly increased in HFD compared with ND mice. Sesamin prevented the increases in blood insulin and lipid levels in HFD-fed mice, but did not affect the plasma glucose. Exercise capacity determined by treadmill tests was significantly reduced in HFD mice, but almost completely recovered in HFD+Sesamin mice. Citrate synthase activity was significantly decreased in the skeletal muscle of HFD mice, and these decreases were also inhibited by sesamin. Superoxide anion and NAD(P)H oxidase activity were significantly increased in HFD mice compared with the ND mice and were ameliorated by sesamin. Sesamin prevented the decline in exercise capacity in HFD-induced diabetic mice via maintenance of mitochondrial function, fat oxidation and attenuation of oxidative stress in the skeletal muscle. Our data suggest that sesamin may be useful as a novel agent for the treatment of diabetes mellitus. [ABSTRACT FROM AUTHOR]

Background. Exercise capacity and quality of life are markedly impaired in chronic kidney disease (CKD). Increased plasma uremic toxins such as indoxyl sulfate (IS), which induce oxidative stress, may be involved in this process. An oral adsorbent, AST-120, can reduce circulating IS, however, its effects on skeletal muscle and exercise capacity have not been investigated in CKD. Methods. Subtotal-nephrectomy or sham operation was performed in 8-week-old C57BL/6J mice. They were divided into two groups with or without 8% (w/w) of AST-120 in standard diet for 20 weeks. Sham, Sham + AST-120, CKD and CKD + AST-120 (n = 12, each group) were studied. We also conducted a C2C12 cell culture study to determine the direct effects of IS on oxidative stress. Results. Plasma IS levels were significantly increased in CKD compared with Sham (1.05 ± 0.11 versus 0.21 ± 0.03 mg/dL, P < 0.05), which was significantly ameliorated in CKD + AST- 120 (0.41 ± 0.06 mg/dL). The running distance to exhaustion determined by treadmill tests was significantly reduced in CKD compared with Sham (267 ± 17 versus 427 ± 36 m, P < 0.05), and this reduction was also significantly ameliorated in CKD + AST-120 (407 ± 38 m) without altering skeletal muscle weight. Citrate synthase activity and mitochondrial biogenesis gene were downregulated, and superoxide production was significantly increased in the skeletal muscle from CKD, and these changes were normalized in CKD + AST-120. Incubation of C2C12 cells with IS significantly increased NAD(P)H oxidase activity. Conclusions. The administration of AST-120 improved exercise capacity and mitochondrial biogenesis of skeletal muscle via reducing oxidative stress. AST-120 may be a novel therapeutic agent against exercise intolerance in CKD. [ABSTRACT FROM AUTHOR]

Recent studies suggest improved outcomes and survival in obese heart failure patients (i.e., the obesity paradox), although obesity and heart failure unfavorably alter cardiac function and metabolism. We investigated the effects of weight loss on cardiac function and metabolism in obese heart failure mice. Obesity and heart failure were induced by feeding mice a high-fat (HF) diet (60% kcal from fat) for 4 weeks, following which an abdominal aortic constriction (AAC) was produced. Four weeks post-AAC, mice were switched to a low-fat (LF) diet (12% kcal from fat; HF AAC LF) or maintained on an HF (HF AAC HF) for a further 10 weeks. After 18 weeks, HF AAC LF mice weighed less than HF AAC HF mice. Diastolic function was improved in HF AAC LF mice, while cardiac hypertrophy was decreased and accompanied by decreased SIRT1 expression, increased FOXO1 acetylation, and increased atrogin-1 expression compared with HF AAC HF mice. Insulin-stimulated glucose oxidation was increased in hearts from HF AAC LF mice, compared with HF AAC HF mice. Thus lowering body weight by switching to LF diet in obese mice with heart failure is associated with decreased cardiac hypertrophy and improvements in both cardiac insulin sensitivity and diastolic function, suggesting that weight loss does not negatively impact heart function in the setting of obesity. [ABSTRACT FROM AUTHOR]

Background Brain-derived neurotropic factor (BDNF) is involved in cardiovascular diseases as well as skeletal muscle energy metabolism and depression. We investigated whether serum BDNF level was associated with prognosis in patients with heart failure (HF). Methods and Results We measured the serum BDNF level in 58 patients with HF (59.2 ± 13.7 years old, New York Heart Association functional class I–III) at baseline, and adverse events, including all cardiac deaths and HF rehospitalizations, were recorded during the median follow-up of 20.3 months. In a univariate analysis, serum BDNF levels were significantly associated with peak oxygen capacity (β = 0.547; P = .003), anaerobic threshold (β = 0.929; P = .004), and log minute ventilation/carbon dioxide production slope (β = −10.15; P = .005), but not Patient Health Questionnaire scores (β = −0.099; P = .586). A multivariate analysis demonstrated that serum BDNF level was an independent prognostic factor of adverse events (hazard ratio 0.41, 95% confidence interval 0.20–0.84; P = .003). The receiver operating characteristic curve demonstrated that low levels of BDNF (<17.4 ng/mL) were associated with higher rates of adverse events compared with high levels of BDNF (≥17.4 ng/mL; log rank test: P < .001). Conclusions Decreased serum BDNF levels were significantly associated with adverse outcomes in HF patients, suggesting that these levels can be a useful prognostic biomarker. [ABSTRACT FROM AUTHOR]

New findings What is the central question of this study? Does angiotensin II directly induce skeletal muscle abnormalities?, What is the main finding and its importance? Angiotensin II induces skeletal muscle abnormalities and reduced exercise capacity. Mitochondrial dysfunction and a decreased number of oxidative fibres are manifest early, while muscle atrophy is seen later. Thus, angiotensin II may play an important role in the skeletal muscle abnormalities observed in a wide variety of diseases., Skeletal muscle abnormalities, such as mitochondrial dysfunction, a decreased percentage of oxidative fibres and atrophy, are the main cause of reduced exercise capacity observed in ageing and various diseases, including heart failure. The renin-angiotensin system, particularly angiotensin II (Ang II), is activated in the skeletal muscle in these conditions. Here, we examined whether Ang II could directly induce these skeletal muscle abnormalities and investigated their time course. Angiotensin II (1000 ng kg−1 min−1) or vehicle was administered to male C57BL/6J mice (10-12 weeks of age) via subcutaneously implanted osmotic minipumps for 1 or 4 weeks. Angiotensin II significantly decreased body and hindlimb skeletal muscle weights compared with vehicle at 4 weeks. In parallel, muscle cross-sectional area was also decreased in the skeletal muscle at 4 weeks. Muscle RING finger-1 and atrogin-1 were significantly increased in the skeletal muscle from mice treated with Ang II. In addition, cleaved caspase-3 and terminal deoxynucleotidyl trasferase-mediated dUTP nick-positive nuclei were significantly increased in mice treated with Ang II at 1 and 4 weeks, respectively. Mitochondrial oxidative enzymes, such as citrate synthase, complex I and complex III activities were significantly decreased in the skeletal muscle from mice treated Ang II at 1 and 4 weeks. NAD(P)H oxidase-derived superoxide production was increased. NADH staining revealed that type I fibres were decreased and type IIb fibres increased in mice treated with Ang II at 1 week. The work and running distance evaluated by a treadmill test were significantly decreased in mice treated with Ang II at 4 weeks. Thus, Ang II could directly induce the abnormalities in skeletal muscle function and structure. [ABSTRACT FROM AUTHOR]

Malnutrition is highly prevalent in patients with heart failure (HF), but the precise impact of dietary energy deficiency on HF patients' clinical outcomes is not known. We investigated the associations between inadequate calorie intake and adverse clinical events in 145 stable outpatients with chronic HF who had a history of hospitalization due to worsening HF. To assess the patients' dietary pattern, we used a brief self-administered diet-history questionnaire (BDHQ). Inadequate calorie intake was defined as <60% of the estimated energy requirement. In the total chronic HF cohort, the median calorie intake was 1628 kcal/day. Forty-four patients (30%) were identified as having an inadequate calorie intake. A Kaplan–Meier analysis revealed that the patients with inadequate calorie intake had significantly worse clinical outcomes including all-cause death and HF-related hospitalization during the 1-year follow-up period versus those with adequate calorie intake (20% vs. 5%, p < 0.01). A multivariate logistic regression analysis showed that inadequate calorie intake was an independent predictor of adverse clinical events after adjustment for various factors that may influence patients' calorie intake. Among patients with chronic HF, inadequate calorie intake was associated with an increased risk of all-cause mortality and rehospitalization due to worsening HF. However, our results are preliminary and larger studies with direct measurements of dietary calorie intake and total energy expenditure are needed to clarify the intrinsic nature of this relationship. [ABSTRACT FROM AUTHOR]

Background: Although type 2 diabetes mellitus (T2DM) is one of the most frequent comorbidities in patients with chronic heart failure (CHF), the effects of T2DM on the exercise capacity of CHF patients are fully unknown. Here, we tested the hypothesis that the coexistence of T2DM lowers CHF patients' peak aerobic capacity. Methods: We retrospectively analyzed the cases of 275 Japanese CHF patients with non-reduced ejection fraction (left ventricular ejection fraction [LVEF] ≥ 40%) or reduced EF (LVEF < 40%) who underwent cardiopulmonary exercise testing. We divided them into diabetic and nondiabetic groups in each CHF cohort. Results: The mean peak oxygen uptake (VO2) value was 16.87 mL/kg/min in the non-reduced LVEF cohort and 15.52 mL/kg/min in the reduced LVEF cohort. The peak VO2 was lower in the diabetics versus the nondiabetics in the non-reduced LVEF cohort with the mean difference (95% confidence interval [95% CI]) of − 0.93 (− 1.82 to − 0.04) mL/kg/min and in the reduced LVEF cohort with the mean difference of − 1.05 (− 1.96 to − 0.15) mL/kg/min, after adjustment for age-squared, gender, anemia, renal function, LVEF, and log B-type natriuretic peptide (BNP). The adjusted VO2 at anaerobic threshold (AT), a submaximal aerobic capacity, was also decreased in the diabetic patients with both non-reduced and reduced LVEFs. Intriguingly, the diabetic patients had a lower adjusted peak O2 pulse than the nondiabetic patients in the reduced LVEF cohort, but not in the non-reduced LVEF cohort. A multivariate analysis showed that the presence of T2DM was an independent predictor of lowered peak VO2 in CHF patients with non-reduced LVEF and those with reduced LVEF. Conclusions: T2DM was associated with lowered peak VO2 in CHF patients with non-reduced or reduced LVEF. The presence of T2DM has a negative impact on CHF patients' exercise capacity, and the degree of impact is partly dependent on their LV systolic function. [ABSTRACT FROM AUTHOR]

A 47-year-old man was diagnosed with non-Hodgkin’s lymphoma (NHL) follicular B-cell type (stage IVB). Although partial remission was observed after the administration of several combination chemotherapeutic agents, no more improvement was observed. After we finished the FND (fludarabine, mitoxantrone, dexamethasone) regimen, the patient’s status improved. After the administration of the FND regimen, thrombocytopenia developed, and the platelet count did not recover to previous levels. After rituximab was administered for the treatment of thrombocytopenia, the platelet count recovered. Then we combined fludarabine and rituximab for the treatment of NHL. Although fludarabine was administered, the platelet count did not decrease when combined with rituximab. In the discussion, we analyze the characteristics and the treatment outcome of the thrombocytopenia induced by fludarabine reviewed in the literature. [ABSTRACT FROM AUTHOR]

Systemic oxidative stress plays a key role in the development of chronic heart failure (CHF). We tested the hypothesis that mitochondrial reactive oxygen species (ROS) generation in circulating peripheral blood mononuclear cells (PBMCs) contributes to CHF progression. A total of 31 patients who had a history of hospital admission due to worsening HF were enrolled and grouped as having either mild CHF defined as New York Heart Association (NYHA) functional class I-II or moderate-to-severe CHF defined as NYHA functional class III. ROS levels in PBMC mitochondria were significantly increased in CHF patients with NYHA functional class III compared to those with NYHA functional class I-II, accompanied by impaired mitochondrial respiratory capacity in PBMCs. ROS generation in PBMC mitochondria was positively correlated with urinary 8-hydroxydeoxyguanosine, a systemic oxidative stress marker, in CHF patients. Importantly, mitochondrial ROS generation in PBMCs was directly correlated with plasma levels of B-type natriuretic peptide, a biomarker for severity of HF, and inversely correlated with peak oxygen uptake, a parameter of exercise capacity, in CHF patients. The study showed that ROS generation in PBMC mitochondria was higher in patients with advanced CHF, and it was associated with disease severity and exercise intolerance in CHF patients. [ABSTRACT FROM AUTHOR]

Background: Branched chain amino acids (BCAA) can impair insulin signaling, and cardiac insulin resistance can occur in the failing heart. We, therefore, determined if cardiac BCAA accumulation occurs in patients with dilated cardiomyopathy (DCM), due to an impaired catabolism of BCAA, and if stimulating cardiac BCAA oxidation can improve cardiac function in mice with heart failure. Method: For human cohorts of DCM and control, both male and female patients of ages between 22 and 66 years were recruited with informed consent from University of Alberta hospital. Left ventricular biopsies were obtained at the time of transplantation. Control biopsies were obtained from non-transplanted donor hearts without heart disease history. To determine if stimulating BCAA catabolism could lessen the severity of heart failure, C57BL/6J mice subjected to a transverse aortic constriction (TAC) were treated between 1 to 4-week post-surgery with either vehicle or a stimulator of BCAA oxidation (BT2, 40 mg/kg/day). Result: Echocardiographic data showed a reduction in ejection fraction (54.3 ± 2.3 to 22.3 ± 2.2%) and an enhanced formation of cardiac fibrosis in DCM patients when compared to the control patients. Cardiac BCAA levels were dramatically elevated in left ventricular samples of patients with DCM. Hearts from DCM patients showed a blunted insulin signalling pathway, as indicated by an increase in P-IRS1ser636/639 and its upstream modulator P-p70S6K, but a decrease in its downstream modulators P-AKT ser473 and in P-GSK3β ser9. Cardiac BCAA oxidation in isolated working hearts was significantly enhanced by BT2, compared to vehicle, following either acute or chronic treatment. Treatment of TAC mice with BT2 significantly improved cardiac function in both sham and TAC mice (63.0 ± 1.8 and 56.9 ± 3.8% ejection fraction respectively). Furthermore, P-BCKDH and BCKDK expression was significantly decreased in the BT2 treated groups. Conclusion: We conclude that impaired cardiac BCAA catabolism and insulin signaling occur in human heart failure, while enhancing BCAA oxidation can improve cardiac function in the failing mouse heart. [ABSTRACT FROM AUTHOR]

Epicardial adipose tissue (EAT), a source of adipokines, is metabolically active, but the role of EAT mitochondria in coronary artery disease (CAD) has not been established. We investigated the association between EAT mitochondrial respiratory capacity, adiponectin concentration in the EAT, and coronary atherosclerosis. EAT samples were obtained from 25 patients who underwent elective cardiac surgery. Based on the coronary angiographycal findings, the patients were divided into two groups; coronary artery disease (CAD; n = 14) and non-CAD (n = 11) groups. The mitochondrial respiratory capacities including oxidative phosphorylation (OXPHOS) capacity with non-fatty acid (complex I and complex I + II-linked) substrates and fatty acids in the EAT were significantly lowered in CAD patients. The EAT mitochondrial OXPHOS capacities had a close and inverse correlation with the severity of coronary artery stenosis evaluated by the Gensini score. Intriguingly, the protein level of adiponectin, an anti-atherogenic adipokine, in the EAT was significantly reduced in CAD patients, and it was positively correlated with the mitochondrial OXPHOS capacities in the EAT and inversely correlated with the Gensini score. Our study showed that impaired mitochondrial OXPHOS capacity in the EAT was closely linked to decreased concentration of adiponectin in the EAT and severity of coronary atherosclerosis. [ABSTRACT FROM AUTHOR]

Background: Alterations in cardiac energy metabolism contribute to the development and severity of heart failure (HF). In severe HF, overall mitochondrial oxidative metabolism is significantly decreased resulting in a reduced energy reserve. However, despite the high prevalence of HF with preserved ejection fraction (HFpEF) in our society, it is not clear what changes in cardiac energy metabolism occur in HFpEF, and whether alterations in energy metabolism contribute to the development of contractile dysfunction. Methods: We directly assessed overall energy metabolism during the development of HFpEF in Dahl salt-sensitive rats fed a high salt diet (HSD) for 3, 6 and 9 weeks. Results: Over the course of 9 weeks, the HSD caused a progressive decrease in diastolic function (assessed by echocardiography assessment of E'/A'). This was accompanied by a progressive increase in cardiac glycolysis rates (assessed in isolated working hearts obtained at 3, 6 and 9 weeks of HSD). In contrast, the subsequent oxidation of pyruvate from glycolysis (glucose oxidation) was not altered, resulting in an uncoupling of glucose metabolism and a significant increase in proton production. Increased glucose transporter (GLUT)1 expression accompanied this elevation in glycolysis. Decreases in cardiac fatty acid oxidation and overall adenosine triphosphate (ATP) production rates were not observed in early HF, but both significantly decreased as HF progressed to HF with reduced EF (i.e. 9 weeks of HSD). Conclusions: Overall, we show that increased glycolysis is the earliest energy metabolic change that occurs during HFpEF development. The resultant increased proton production from uncoupling of glycolysis and glucose oxidation may contribute to the development of HFpEF. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Enhanced mitochondrial oxidative metabolism in peripheral blood mononuclear cells is associated with fatty liver in obese young adults." The original article contained errors in Figure 1 and its accompanying legend, specifically regarding complex II and its surroundings. The corrected version of the article is available online. The article discusses the evaluation of mitochondrial respiratory capacity in obese and healthy control subjects using a specific protocol. The correction notice provides a summarized explanation of the respiratory states and substrates used in the study. [Extracted from the article]

Systemic inflammation underlies the association between obesity and nonalcoholic fatty liver disease (NAFLD). Here, we investigated functional changes in leukocytes' mitochondria in obese individuals and their associations with NAFLD. We analyzed 14 obese male Japanese university students whose body mass index was > 30 kg/m2 and 15 healthy age- and sex-matched lean university students as controls. We observed that the mitochondrial oxidative phosphorylation (OXPHOS) capacity with complex I + II-linked substrates in peripheral blood mononuclear cells (PBMCs), which was measured using a high-resolution respirometry, was significantly higher in the obese group versus the controls. The PBMCs' mitochondrial complex IV capacity was also higher in the obese subjects. All of the obese subjects had hepatic steatosis defined by a fatty liver index (FLI) score ≥ 60, and there was a positive correlation between their FLI scores and their PBMCs' mitochondrial OXPHOS capacity. The increased PBMCs' mitochondrial OXPHOS capacity was associated with insulin resistance, systemic inflammation, and higher serum levels of interleukin-6 in the entire series of subjects. Our results suggest that the mitochondrial respiratory capacity is increased in the PBMCs at the early stage of obesity, and the enhanced PBMCs' mitochondrial oxidative metabolism is associated with hepatic steatosis in obese young adults. [ABSTRACT FROM AUTHOR]

Background It has been reported that skeletal muscle mass and strength are decreased in patients with heart failure (HF), and HF is associated with both reduced exercise capacity and adverse clinical outcomes. Myostatin has been known as a negative regulator of muscle growth, follistatin as the myostatin antagonist, maintaining tissue homeostasis. We thus determined serum myostatin levels in HF patients and whether they are associated with skeletal muscle wasting. Methods and results Forty one consecutive HF patients (58 ± 15 years old, New York Heart Association class I–III) and 30 age-matched healthy subjects as controls (53 ± 8 years old) were studied. Serum myostatin levels were significantly lower in HF patients than controls (18.7 ± 7.4 vs. 23.6 ± 5.2 ng/mL, P < 0.001). Circumference of the thickest part of the right thigh was significantly small (468 ± 72 vs. 559 ± 37 mm, P = 0.001) and lower extremity muscular strength was lower in patients with HF (129 ± 55 vs. 219 ± 52 N × m, P < 0.001). Fourteen HF patients (34%) had muscle wasting. By univariate analysis, higher age, higher serum follistatin, and lower serum myostatin were significantly associated with the presence of muscle wasting. By multivariate analysis, serum myostatin levels were independently associated with muscle wasting (OR = 0.77, 95% CI [0.58, 0.93], P = 0.02). Conclusion Serum myostatin levels were significantly decreased in HF patients and associated with lower extremity muscle wasting, suggesting that myostatin may be an important factor for maintaining skeletal muscle mass and strength in HF. [ABSTRACT FROM AUTHOR]

New Findings: What is the central question of this study?We questioned whether an angiotensin‐converting enzyme (ACE) inhibitor prevents skeletal muscle fibrosis in diabetic mice.What is the main finding and its importance?Administration of ACE inhibitor prevents the increase in skeletal muscle fibrosis during the early phase after induction of diabetes by streptozotocin. Our findings might provide a new therapeutic target for skeletal muscle abnormalities in diabetes. Fibrosis is characterized by the excessive production and accumulation of extracellular matrix components, including collagen. Although the extracellular matrix is an essential component of skeletal muscle, fibrosis can have negative effects on muscle function. Skeletal muscle fibrosis was shown to be increased in spontaneously hypertensive rats and to be prevented by an angiotensin‐converting enzyme (ACE) inhibitor, an antihypertensive drug, in dystrophic mice or a mouse model of myocardial infarction. In this study, we therefore analysed whether (1) there is increased skeletal muscle fibrosis in streptozotocin (STZ)‐induced diabetic mice, and (2) a preventive effect on skeletal muscle fibrosis by administration of an ACE inhibitor. Skeletal muscle fibrosis was significantly increased in STZ‐induced diabetic mice compared with control mice from 2 to 14 days post‐STZ. The ACE inhibitor prevented both skeletal muscle fibrosis and the reduction in muscle function in STZ‐treated mice. Our study demonstrated that administration of an ACE inhibitor prevents the increase in skeletal muscle fibrosis during the early phase after onset of diabetes. Our findings might provide a new therapeutic target for skeletal muscle abnormalities in diabetes. Future studies are required to clarify whether skeletal muscle fibrosis is also linked directly to physical activity. [ABSTRACT FROM AUTHOR]

Sarcopenia is characterized by muscle mass and strength loss and reduced physical activity. Branched-chain amino acids (BCAAs) were recently described as an activator of protein synthesis via mammalian target of rapamycin (mTOR) signaling for muscle atrophy. In cardiovascular diseases, excessive activation of the renin-angiotensin system may induce an imbalance of protein synthesis and degradation, and this plays a crucial role in muscle atrophy. We investigated the effects of BCAAs on angiotensin II (Ang II)-induced muscle atrophy in mice. We administered Ang II (1000 ng/kg/min) or vehicle to 10–12-week-old male C57BL/6J mice via subcutaneous osmotic minipumps for 4 weeks with or without BCAA supplementation (3% BCAA in tap water). The skeletal muscle weight/tibial length and cross-sectional area were smaller in the Ang II mice than the vehicle mice; these changes were induced by an imbalance of protein synthesis and degradation signaling such as Akt/mTOR and MuRF-1/Atrogin-1. Compared to the Ang II mice, the mTOR signaling was significantly activated and Ang II-induced muscle atrophy was ameliorated in the Ang II + BCAA mice, and this attenuated the reduction of exercise capacity. Notably, the decrease of muscle weight/tibial length in the fast-twitch dominant muscles (e.g., the extensor digitorum longus) was significantly ameliorated compared to that in the slow-twitch dominant muscles (e.g., soleus). Histologically, the effect of BCAA was larger in fast-twitch than slow-twitch fibers, which may be related to the difference in BCAA catabolism. BCAA supplementation could contribute to the prevention of skeletal muscle atrophy induced by Ang II. Unlabelled Image [ABSTRACT FROM AUTHOR]

Heart failure (HF) occurs frequently among older individuals, and dysfunction of cardiac mitochondria is often observed. We here show the cardiac-specific downregulation of a certain mitochondrial component during the chronological aging of mice, which is detrimental to the heart. MitoNEET is a mitochondrial outer membrane protein, encoded by CDGSH iron sulfur domain 1 (CISD1). Expression of mitoNEET was specifically downregulated in the heart and kidney of chronologically aged mice. Mice with a constitutive cardiac-specific deletion of CISD1 on the C57BL/6J background showed cardiac dysfunction only after 12 months of age and developed HF after 16 months; whereas irregular morphology and higher levels of reactive oxygen species in their cardiac mitochondria were observed at earlier time points. Our results suggest a possible mechanism by which cardiac mitochondria may gradually lose their integrity during natural aging, and shed light on an uncharted molecular basis closely related to age-associated HF. Takaaki Furihata et al. report a new mouse model with heart-specific deletion of the mitochondrial protein, mitoNEET. Their results suggest that loss of mitoNEET expression may contribute to age-associated heart failure in older adults. [ABSTRACT FROM AUTHOR]

Oxidative stress plays a role in the progression of chronic heart failure (CHF). We investigated whether systemic oxidative stress is linked to exercise intolerance and skeletal muscle abnormalities in patients with CHF. We recruited 30 males: 17 CHF patients, 13 healthy controls. All participants underwent blood testing, cardiopulmonary exercise testing, and magnetic resonance spectroscopy (MRS). The serum thiobarbituric acid reactive substances (TBARS; lipid peroxides) were significantly higher (5.1 ± 1.1 vs. 3.4 ± 0.7 μmol/L, p < 0.01) and the serum activities of superoxide dismutase (SOD), an antioxidant, were significantly lower (9.2 ± 7.1 vs. 29.4 ± 9.7 units/L, p < 0.01) in the CHF cohort versus the controls. The oxygen uptake (VO2) at both peak exercise and anaerobic threshold was significantly depressed in the CHF patients; the parameters of aerobic capacity were inversely correlated with serum TBARS and positively correlated with serum SOD activity. The phosphocreatine loss during plantar-flexion exercise and intramyocellular lipid content in the participants' leg muscle measured by 31phosphorus- and 1proton-MRS, respectively, were significantly elevated in the CHF patients, indicating abnormal intramuscular energy metabolism. Notably, the skeletal muscle abnormalities were related to the enhanced systemic oxidative stress. Our analyses revealed that systemic oxidative stress is related to lowered whole-body aerobic capacity and skeletal muscle dysfunction in CHF patients. [ABSTRACT FROM AUTHOR]

Background: Transforming growth factor beta (TGF-β)-Smad2/3 is the major signaling pathway of fibrosis, which is characterized by the excessive production and accumulation of extracellular matrix (ECM) components, including collagen. Although the ECM is an essential component of skeletal muscle, fibrosis may be harmful to muscle function. On the other hand, our previous studies have shown that levels of angiotensin II, which acts upstream of TGF-β-Smad2/3 signaling, is increased in mice with myocardial infarction (MI). In this study, we found higher skeletal muscle fibrosis in MI mice compared with control mice, and we investigated the mechanisms involved therein. Moreover, we administered an inhibitor based on the above mechanism and investigated its preventive effects on skeletal muscle fibrosis. Methods: Male C57BL/6 J mice with MI were created, and sham-operated mice were used as controls. The time course of skeletal muscle fibrosis post-MI was analyzed by picrosirius-red staining (days 1, 3, 7, and 14). Mice were then divided into 3 groups: sham + vehicle (Sham + Veh), MI + Veh, and MI + lisinopril (an angiotensin-converting enzyme [ACE] inhibitor, 20 mg/kg body weight/day in drinking water; MI + Lis). Lis or Veh was administered from immediately after the surgery to 14 days postsurgery. Results: Skeletal muscle fibrosis was significantly increased in MI mice compared with sham mice from 3 to 14 days postsurgery. Although mortality was lower in the MI + Lis mice than the MI + Veh mice, there was no difference in cardiac function between the 2 groups at 14 days. Skeletal muscle fibrosis and hydroxyproline (a key marker of collagen content) were significantly increased in MI + Veh mice compared with the Sham + Veh mice. Consistent with these results, protein expression of TGF-β and phosphorylated Smad2/3 in the skeletal muscle during the early time points after surgery (days 1–7 postsurgery) and blood angiotensin II at 14 days postsurgery was increased in MI mice compared with sham mice. These impairments were improved in MI + Lis mice, without any effects on spontaneous physical activity, muscle strength, muscle weight, and blood pressure. Conclusions: ACE inhibitor administration prevents increased skeletal muscle fibrosis during the early phase after MI. Our findings indicate a new therapeutic target for ameliorating skeletal muscle abnormalities in heart diseases. [ABSTRACT FROM AUTHOR]

New Findings: What is the central question of this study?We questioned whether the disruption of invariant natural killer T (iNKT) cells exacerbates left ventricular (LV) remodelling and heart failure after transverse aortic constriction in mice.What are the main findings and their importance?Pressure overload induced by transverse aortic constriction increased the infiltration of iNKT cells in mouse hearts. The disruption of iNKT cells exacerbated LV remodelling and hastened the transition from hypertrophy to heart failure, in association with the activation of mitogen‐activated protein kinase signalling. Activation of iNKT cells modulated the immunological balance in this process and played a protective role against LV remodelling and failure. Chronic inflammation is involved in the development of cardiac remodelling and heart failure (HF). Invariant natural killer T (iNKT) cells, a subset of T lymphocytes, have been shown to produce various cytokines and orchestrate tissue inflammation. The pathophysiological role of iNKT cells in HF caused by pressure overload has not been studied. In the present study, we investigated whether the disruption of iNKT cells affected this process in mice. Transverse aortic constriction (TAC) and a sham operation were performed in male C57BL/6J wild‐type (WT) and iNKT cell‐deficient Jα18 knockout (KO) mice. The infiltration of iNKT cells was increased after TAC. The disruption of iNKT cells exacerbated left ventricular (LV) remodelling and hastened the transition to HF after TAC. Histological examinations also revealed that the disruption of iNKT cells induced greater myocyte hypertrophy and a greater increase in interstitial fibrosis after TAC. The expressions of interleukin‐10 and tumour necrosis factor‐α mRNA and their ratio in the LV after TAC were decreased in the KO compared with WT mice, which might indicate that the disruption of iNKT cells leads to an imbalance between T‐helper type 1 and type 2 cytokines. The phosphorylation of extracellular signal‐regulated kinase was significantly increased in the KO mice. The disruption of iNKT cells exacerbated the development of cardiac remodelling and HF after TAC. The activation of iNKT cells might play a protective role against HF caused by pressure overload. Targeting the activation of iNKT cells might thus be a promising candidate as a new therapeutic strategy for HF. [ABSTRACT FROM AUTHOR]

Decreased exercise capacity, which is an independent predictor of the poor prognosis of patients with heart failure (HF), is attributed to markedly impaired skeletal muscle mitochondrial function and fatty acid oxidation. Previous studies reported that the administration of an inhibitor of sodium-glucose cotransporter 2 (SGLT2) increases ketone body production and fat utilization in type 2 diabetic mice. In this study, we investigated the effects of SGLT2 inhibitor administration on exercise endurance and skeletal muscle mitochondrial function with fatty acid oxidation in a murine model of HF after the induction of myocardial infarction (MI). Two weeks post-MI, HF mice were divided into 2 groups, i.e., with or without treatment with the SGLT2 inhibitor empagliflozin (Empa, 300 mg/kg of food). Consistent with previous studies, urinary glucose and blood beta-hydroxybutyrate levels were increased in the HF+Empa mice compared with the sham and HF mice 4 weeks after the start of Empa administration. Exercise endurance capacity was limited in the HF mice but was ameliorated in the HF+Empa mice, without any effects on cardiac function, food intake, spontaneous physical activity, skeletal muscle strength, and skeletal muscle weight. Mitochondrial oxidative phosphorylation capacity with fatty acid substrates was reduced in the skeletal muscle of HF mice, and this decrease was ameliorated in the HF+Empa mice. Our results demonstrate that SGLT2 inhibitors may be novel therapeutics against reduced exercise endurance capacity in HF, by improving mitochondrial fatty acid oxidation in skeletal muscle. [ABSTRACT FROM AUTHOR]

Mitochondrial function is reduced in skeletal muscles of many patients with systemic diseases and it is difficult to deliver medicinal substances to mitochondria in such tissue. In this study, we report on attempts to develop liposome-based carriers for mitochondrial delivery using mouse myoblasts (C2C12) by varying the lipid composition of the carriers. We found that a liposome that contains an optimal lipid modified with the KALA peptide (a cellular uptake and mitochondrial targeting device) was the most effective nanocarrier for achieving mitochondrial delivery in C2C12 cells. We also report on successful mitochondrial transgene expression using the carriers encapsulating a mitochondrial DNA vector as we previously reported. • We succeeded in developing a nano carrier for mitochondrial delivery using myoblasts. • We also report on successful mitochondrial transgene expression using this carrier. • A KALA peptide modification to a liposome was effective for mitochondrial delivery. [ABSTRACT FROM AUTHOR]

Liver stiffness (LS) has been reported to be a marker of liver congestion caused by elevated central venous pressure in heart failure (HF) patients. Recent studies demonstrated that LS could be non-invasively measured by virtual touch quantification (VTQ). However, its prognostic implication in patients with acute decompensated heart failure (ADHF) is unclear. This study sought to determine whether LS measured by VTQ could be a determinant of subsequent adverse events in ADHF patients. We prospectively recruited 70 ADHF patients who underwent LS measurement by VTQ on admission in our university hospital between June 2016 and April 2018. The primary outcome of interest was the composite of all-cause mortality and worsening HF. During a median follow-up period of 272 (interquartile range 122–578) days, there were 26 (37%) events, including 5 (7%) deaths and 21 (30%) cases of worsening HF. The c-index of LS for predicting the composite of adverse events was 0.77 (95% CI 0.66–0.88), and the optimal cut-off value of LS was 1.50 m/s. Adverse events were more frequently observed in patients with high LS (≥ 1.50 m/s) compared to those with low LS (< 1.50 m/s). Multivariable Cox regression analyzes revealed that higher LS was independently associated with increased subsequent risk of adverse events after adjustment for confounders. In conclusion, high admission LS was an independent determinant of worse clinical outcomes in patients with ADHF. This finding suggests that LS on admission is useful for risk stratification of patients with ADHF. [ABSTRACT FROM AUTHOR]

Abstract The mitochondrial calcium uniporter (MCU) relays cytosolic Ca2+ transients to the mitochondria. We examined whether energy metabolism was compromised in hearts from mice with a cardiac-specific deficiency of MCU subjected to an isoproterenol (ISO) challenge. Surprisingly, isolated working hearts from cardiac MCU-deficient mice showed higher cardiac work, both in the presence or absence of ISO. These hearts were not energy-starved, with ISO inducing a similar increase in glucose oxidation rates compared to control hearts, but a greater increase in fatty acid oxidation rates. This correlated with lower levels of the fatty acid oxidation inhibitor malonyl CoA, and to an increased stimulatory acetylation of its degrading enzyme malonyl CoA decarboxylase and of the fatty acid β-oxidation enzyme β-hydroxyacyl CoA dehydrogenase. We conclude that impaired mitochondrial Ca2+ uptake does not compromise cardiac energetics due to a compensatory stimulation of fatty acid oxidation that provides a higher energy reserve during acute adrenergic stress. Highlights • The MCU is dispensable for baseline and isoproterenol-stimulated cardiac function. • MCU deletion does not compromise cardiac energetics. • Impaired MCU function increases the acetylation of key metabolic enzymes. • Deletion of MCU enhances fatty acid oxidation under increased cardiac workload. [ABSTRACT FROM AUTHOR]

We have reported that exercise capacity is reduced in high fat diet (HFD)-induced diabetic mice, and that this reduction is associated with impaired mitochondrial function in skeletal muscle (SKM). However, it remains to be clarified whether the treatment of diabetes ameliorates the reduced exercise capacity. Therefore, we examined whether an insulin-sensitizing drug, pioglitazone, could improve exercise capacity in HFD mice. C57BL/6J mice were fed a normal diet (ND) or HFD, then treated with or without pioglitazone (3 mg/kg/day) to yield the following 4 groups: ND+vehicle, ND+pioglitazone, HFD+vehicle, and HFD+pioglitazone ( n =10 each). After 8 weeks, body weight, plasma glucose, and insulin in the HFD+vehicle were significantly increased compared to the ND+vehicle group. Pioglitazone normalized the insulin levels in HFD-fed mice, but did not affect the body weight or plasma glucose. Exercise capacity determined by treadmill tests was significantly reduced in the HFD+vehicle, and this reduction was almost completely ameliorated in HFD+pioglitazone mice. ADP-dependent mitochondrial respiration, complex I and III activities, and citrate synthase activity were significantly decreased in the SKM of the HFD+vehicle animals, and these decreases were also attenuated by pioglitazone. NAD(P)H oxidase activity was significantly increased in the HFD+vehicle compared with the ND+vehicle, and this increase was ameliorated in HFD+pioglitazone mice. Pioglitazone improved the exercise capacity in diabetic mice, which was due to the improvement in mitochondrial function and attenuation of oxidative stress in the SKM. Our data suggest that pioglitazone may be useful as an agent for the treatment of diabetes mellitus. [ABSTRACT FROM AUTHOR]

Invariant natural killer T (iNKT) cells orchestrate tissue inflammation via regulating various cytokine productions. However the role of iNKT cells has not been determined in myocardial ischemia/reperfusion (I/R) injury. The purpose of this study was to examine whether the activation of iNKT cells by α-galactosylceramide (α-GC), which specifically activates iNKT cells, could affect myocardial I/R injury. I/R or sham operation was performed in male C57BL/6J mice. I/R mice received the injection of either αGC (I/R+αGC, n=48) or vehicle (I/R+vehicle, n=49) 30min before reperfusion. After 24h, infarct size/area at risk was smaller in I/R+αGC than in I/R+vehicle (37.8±2.7% vs. 47.1±2.5%, P <0.05), with no significant changes in area at risk. The numbers of infiltrating myeloperoxidase- and CD3-positive cells were lower in I/R+αGC. Apoptosis evaluated by TUNEL staining and caspase-3 protein was also attenuated in I/R+αGC. Myocardial gene expression of tumor necrosis factor-α and interleukin (IL)-1β in I/R+αGC was lower to 46% and 80% of that in I/R+vehicle, respectively, whereas IL-10, IL-4, and interferon (IFN)-γ were higher in I/R+αGC than I/R+vehicle by 2.0, 4.1, and 9.6 folds, respectively. The administration of anti-IL-10 receptor antibody into I/R+αGC abolished the protective effects of αGC on I/R injury (infarct size/area at risk: 53.1±5.2% vs. 37.4±3.5%, P <0.05). In contrast, anti-IL-4 and anti-IFN-γ antibodies did not exert such effects. In conclusion, activated iNKT cells by αGC play a protective role against myocardial I/R injury through the enhanced expression of IL-10. Therapies designed to activate iNKT cells might be beneficial to protect the heart from I/R injury. [ABSTRACT FROM AUTHOR]

Objectives: Sarcopenia and malnutrition often occur simultaneously in adults with cardiovascular diseases. Our objective was to determine the associations of preoperative sarcopenia and malnutrition with major adverse cardiac and cerebral events (MACCE) after cardiac surgery., Methods: We retrospectively analysed 154 consecutive patients who underwent elective cardiac surgery between January 2015 and June 2018 at two institutions in Japan. Sarcopenia and nutritional status were preoperatively assessed by bilateral psoas muscle volume index (PMVI) using CT scans and the prognostic nutritional index (PNI), respectively., Results: The median age in the total cohort was 69 years, and 43% were women. Within 30 days after surgery, 20 patients developed in-hospital MACCE and seven patients died of any cause. Low PMVI (<72.25 cm3/m2) and low PNI (<48.15) were each independent predictors of postoperative MACCE occurrence with odds ratios (95% confidence interval) of 3.58 (1.22-10.53) and 3.73 (1.25-11.09) when adjusted for age and sex, and 3.25 (1.07-9.87) and 3.27 (1.08-9.89) when adjusted for preoperative left ventricular ejection fraction, angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker, and anticoagulant. In addition, the combination of low PMVI and low PNI conferred the highest risk of in-hospital MACCE among the four groups (i.e. the low PMVI, low PNI, low PMVI + low PNI and neither low PMVI nor low PNI groups)., Conclusions: Preoperative low PMVI and low PNI were respectively associated with 30-day in-hospital MACCE occurrence after cardiac surgery. Notably, coexistence of these reductions further enhanced the risk of postoperative MACCE., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Hyperuricemia is an independent predictor of mortality in patients with chronic heart failure (CHF). To determine whether febuxostat, a urate-lowering agent, may improve clinical outcomes in CHF patients, we conducted a multicenter, prospective, randomized, open-label, blinded endpoint study with a treatment period of 24 weeks. We randomly assigned Japanese outpatients diagnosed with both CHF with reduced left ventricular ejection fraction (LVEF < 40%) and asymptomatic hyperuricemia (serum uric acid [UA] levels > 7.0 mg/dl and < 10.0 mg/dl) to either a febuxostat group (n = 51) or a control group (n = 50). The primary efficacy endpoint was the change in log-transformed plasma B-type natriuretic peptide (BNP) levels from baseline to week 24 (or at discontinuation). The secondary efficacy endpoints were the changes in LV systolic or diastolic function evaluated by echocardiography, New York Heart Association (NYHA) class, hemoglobin, and estimated glomerular filtration rate from baseline to week 24, and the change in log-transformed plasma BNP levels or serum UA levels from baseline to weeks 4, 8, 12, 16 and 20 (BNP) or weeks 4, 8, 12, 16, 20 and 24 (serum UA). The primary safety endpoints were occurrence of all-cause death or major cardiovascular events. The mean age of participants was 70 years; 14% were female. The febuxostat group and the control group did not differ with respect to the primary efficacy endpoint (p = 0.13), although the decrease in log-transformed plasma BNP levels from baseline to each of weeks 4, 8, 12, 16 and 20 was greater in the febuxostat group. There were no significant differences between the two groups in the primary safety endpoints or the secondary efficacy endpoints except reduced serum UA levels in the febuxostat group. Febuxostat did not reduce plasma BNP levels at week 24 in patients with CHF, but it appeared safe with no increase in major cardiovascular events and all-cause or cardiovascular mortality., (© 2024. Springer Nature Japan KK, part of Springer Nature.)

Aims: We evaluated a self-care intervention with a novel mobile application (app) in chronic heart failure (HF) patients. To facilitate patient-centred care in HF management, we developed a self-care support mobile app to boost HF patients' optimal self-care., Methods and Results: We conducted a multicentre, randomized, controlled study evaluating the feasibility of the self-care support mobile app designed for use by HF patients. The app consists of a self-monitoring assistant, education, and automated alerts of possible worsening HF. The intervention group received a tablet personal computer (PC) with the self-care support app installed, and the control group received a HF diary. All patients performed self-monitoring at home for 2 months. Their self-care behaviours were evaluated by the European Heart Failure Self-Care Behaviour Scale. We enrolled 24 outpatients with chronic HF (ages 31-78 years; 6 women, 18 men) who had a history of HF hospitalization. During the 2 month study period, the intervention group ( n = 13) showed excellent adherence to the self-monitoring of each vital sign, with a median [interquartile range (IQR)] ratio of self-monitoring adherence for blood pressure, body weight, and body temperature at 100% (92-100%) and for oxygen saturation at 100% (91-100%). At 2 months, the intervention group's self-care behaviour score was significantly improved compared with the control group ( n = 11) [median (IQR): 16 (16-22) vs. 28 (20-36), P = 0.02], but the HF Knowledge Scale, the General Self-Efficacy Scale, and the Short Form-8 Health Survey scores did not differ between the groups., Conclusion: The novel mobile app for HF is feasible., Competing Interests: Conflicts of interest: T.Y. has received a consulting fee from Ambi Inc. M.O. and M.Y. are employees of Hitachi, Ltd. I.Y. has received speaker fees from Chugai Pharmaceutical Co., AstraZeneca, and Nippon Shinyaku Co. H.T. has received personal fees from MSD, Astellas, Pfizer, Bristol–Myers Squibb, Otsuka Pharmaceutical, Daiichi Sankyo, Mitsubishi Tanabe Pharma, Nippon Boehringer Ingelheim, Takeda Pharmaceutical, Bayer Yakuhin, Novartis Pharma, Kowa Pharmaceutical, Teijin Pharma, Medical Review Co., and the Japanese Journal of Clinical Medicine; non-financial support from Actelion Pharmaceuticals, Japan Tobacco Inc., Mitsubishi Tanabe Pharma, Nippon Boehringer Ingelheim, Daiichi Sankyo, IQVIA Services Japan, and Omron Healthcare Co.; and grants from Astellas, Novartis Pharma, Daiichi Sankyo, Takeda Pharmaceutical, Mitsubishi Tanabe Pharma, Teijin Pharma, and MSD outside the submitted work. The other authors declare no conflicts of interest relevant to the study. Hitachi, Ltd., had no role in the data collection, analysis, or interpretation of the data., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Heart failure (HF) is a leading cause of death and repeated hospitalizations and often involves cardiac mitochondrial dysfunction. However, the underlying mechanisms largely remain elusive. Here, using a mouse model in which myocardial infarction (MI) was induced by coronary artery ligation, we show the metabolic basis of mitochondrial dysfunction in chronic HF. Four weeks after ligation, MI mice showed a significant decrease in myocardial succinyl-CoA levels, and this decrease impaired the mitochondrial oxidative phosphorylation (OXPHOS) capacity. Heme synthesis and ketolysis, and protein levels of several enzymes consuming succinyl-CoA in these events, were increased in MI mice, while enzymes synthesizing succinyl-CoA from α-ketoglutarate and glutamate were also increased. Furthermore, the ADP-specific subunit of succinyl-CoA synthase was reduced, while its GDP-specific subunit was almost unchanged. Administration of 5-aminolevulinic acid, an intermediate in the pathway from succinyl-CoA to heme synthesis, appreciably restored succinyl-CoA levels and OXPHOS capacity and prevented HF progression in MI mice. Previous reports also suggested the presence of succinyl-CoA metabolism abnormalities in cardiac muscles of HF patients. Our results identified that changes in succinyl-CoA usage in different metabolisms of the mitochondrial energy production system is characteristic to chronic HF, and although similar alterations are known to occur in healthy conditions, such as during strenuous exercise, they may often occur irreversibly in chronic HF leading to a decrease in succinyl-CoA. Consequently, nutritional interventions compensating the succinyl-CoA consumption are expected to be promising strategies to treat HF.