Low-carbohydrate diets containing plant-derived fat but not animal-derived fat ameliorate heart failure.

Cardiovascular disease (CVD) is a global health burden in the world. Although low-carbohydrate diets (LCDs) have beneficial effects on CVD risk, their preventive effects remain elusive. We investigated whether LCDs ameliorate heart failure (HF) using a murine model of pressure overload. LCD with plant-derived fat (LCD-P) ameliorated HF progression, whereas LCD with animal-derived fat (LCD-A) aggravated inflammation and cardiac dysfunction. In the hearts of LCD-P-fed mice but not LCD-A, fatty acid oxidation-related genes were highly expressed, and peroxisome proliferator-activated receptor α (PPARα), which regulates lipid metabolism and inflammation, was activated. Loss- and gain-of-function experiments indicated the critical roles of PPARα in preventing HF progression. Stearic acid, which was more abundant in the serum and heart of LCD-P-fed mice, activated PPARα in cultured cardiomyocytes. We highlight the importance of fat sources substituted for reduced carbohydrates in LCDs and suggest that the LCD-P-stearic acid-PPARα pathway as a therapeutic target for HF.

A Cold-Blooded Tiptoer: Nonresolving Cellulitis in an Immunocompromised Patient.

Mycobacterium haemophilum is a nontuberculous mycobacteria (NTM) with a predilection for skin and soft tissue infection (SSTI) in the immunocompromised host. We report a case of disseminated M haemophilum infection initially presenting as a nonresolving subacute cellulitis of bilateral lower extremities. Genetic sequencing was used for final identification, while a commercially available polymerase chain reaction test returned a false-positive result for Mycobacterium intracellulare. Consequently, we highlight the importance of M haemophilum as a major differential diagnosis of SSTI in the immunocompromised host and the need for careful interpretation of rapid diagnostic tests.

Effect of Oral Branched-Chain Amino Acids on Serum Albumin Concentration in Heart Failure Patients with Hypoalbuminemia: Results of a Preliminary Study.

BACKGROUND: We conducted a randomized, controlled trial to determine whether supplementation with oral branched-chain amino acids (BCAAs) improves serum albumin and clinical outcomes in heart failure (HF) patients with hypoalbuminemia. METHODS AND RESULTS: We randomly assigned 18 in-hospital HF patients with serum albumin < 3.5 g/dL to receive oral BCAA granules (LIVACT®) for 28 days during their hospital stay or until discharge (BCAA group; N = 9) or to receive no supplementation (controls; N = 9), in addition to recommended HF therapy. The primary endpoints were changes from baseline in serum albumin and cardiothoracic ratio (CTR). Sixteen patients completed the study. The mean (± standard deviation) period of BCAA supplementation was 18.4 ± 8.4 days. Serum albumin significantly increased in the BCAA group [mean difference vs baseline, 0.44 g/dL; 95% confidence interval (CI) 0.13-0.76; P = 0.014] and did not change in controls (0.18 g/dL; 95% CI - 0.05 to 0.40; P = 0.108). CTR significantly decreased in the BCAA group (- 2.3%; 95% CI - 3.8 to - 0.8; P = 0.014) and did not change in controls (- 1.0%; 95% CI - 2.3 to 0.3; P = 0.111). CONCLUSION: In-hospital HF patients with hypoalbuminemia supplemented with BCAAs showed increased serum albumin and decreased CTR. Clinical trial registration number UMIN000004488 [ http://www.umin.ac.jp/ctr/index.htm ].

Mitochondrial Reactive Oxygen Species in Lipotoxic Hearts Induce Post-Translational Modifications of AKAP121, DRP1, and OPA1 That Promote Mitochondrial Fission.

RATIONALE: Cardiac lipotoxicity, characterized by increased uptake, oxidation, and accumulation of lipid intermediates, contributes to cardiac dysfunction in obesity and diabetes mellitus. However, mechanisms linking lipid overload and mitochondrial dysfunction are incompletely understood. OBJECTIVE: To elucidate the mechanisms for mitochondrial adaptations to lipid overload in postnatal hearts in vivo. METHODS AND RESULTS: Using a transgenic mouse model of cardiac lipotoxicity overexpressing ACSL1 (long-chain acyl-CoA synthetase 1) in cardiomyocytes, we show that modestly increased myocardial fatty acid uptake leads to mitochondrial structural remodeling with significant reduction in minimum diameter. This is associated with increased palmitoyl-carnitine oxidation and increased reactive oxygen species (ROS) generation in isolated mitochondria. Mitochondrial morphological changes and elevated ROS generation are also observed in palmitate-treated neonatal rat ventricular cardiomyocytes. Palmitate exposure to neonatal rat ventricular cardiomyocytes initially activates mitochondrial respiration, coupled with increased mitochondrial polarization and ATP synthesis. However, long-term exposure to palmitate (>8 hours) enhances ROS generation, which is accompanied by loss of the mitochondrial reticulum and a pattern suggesting increased mitochondrial fission. Mechanistically, lipid-induced changes in mitochondrial redox status increased mitochondrial fission by increased ubiquitination of AKAP121 (A-kinase anchor protein 121) leading to reduced phosphorylation of DRP1 (dynamin-related protein 1) at Ser637 and altered proteolytic processing of OPA1 (optic atrophy 1). Scavenging mitochondrial ROS restored mitochondrial morphology in vivo and in vitro. CONCLUSIONS: Our results reveal a molecular mechanism by which lipid overload-induced mitochondrial ROS generation causes mitochondrial dysfunction by inducing post-translational modifications of mitochondrial proteins that regulate mitochondrial dynamics. These findings provide a novel mechanism for mitochondrial dysfunction in lipotoxic cardiomyopathy.

Enhanced cardiac Akt/protein kinase B signaling contributes to pathological cardiac hypertrophy in part by impairing mitochondrial function via transcriptional repression of mitochondrion-targeted nuclear genes.

Sustained Akt activation induces cardiac hypertrophy (LVH), which may lead to heart failure. This study tested the hypothesis that Akt activation contributes to mitochondrial dysfunction in pathological LVH. Akt activation induced LVH and progressive repression of mitochondrial fatty acid oxidation (FAO) pathways. Preventing LVH by inhibiting mTOR failed to prevent the decline in mitochondrial function, but glucose utilization was maintained. Akt activation represses expression of mitochondrial regulatory, FAO, and oxidative phosphorylation genes in vivo that correlate with the duration of Akt activation in part by reducing FOXO-mediated transcriptional activation of mitochondrion-targeted nuclear genes in concert with reduced signaling via peroxisome proliferator-activated receptor α (PPARα)/PGC-1α and other transcriptional regulators. In cultured myocytes, Akt activation disrupted mitochondrial bioenergetics, which could be partially reversed by maintaining nuclear FOXO but not by increasing PGC-1α. Thus, although short-term Akt activation may be cardioprotective during ischemia by reducing mitochondrial metabolism and increasing glycolysis, long-term Akt activation in the adult heart contributes to pathological LVH in part by reducing mitochondrial oxidative capacity.

IRF3 regulates cardiac fibrosis but not hypertrophy in mice during angiotensin II-induced hypertension.

Hypertension is a typical modern lifestyle-related disease that is closely associated with the development of cardiovascular disorders. Elevation of angiotensin II (ANG II) is one of several critical factors for hypertension and heart failure; however, the mechanisms underlying the ANG II-mediated pathogenesis are still poorly understood. Here, we show that ANG II-mediated cardiac fibrosis, but not hypertrophy, is regulated by interferon regulatory factor 3 (IRF3), which until now has been exclusively studied in the innate immune system. In a ANG II-infusion mouse model (3.0 mg/kg/d), we compared IRF3-deficient mice (Irf3(-/-)/Bcl2l12(-/-)) with matched wild-type (WT) controls. The development of cardiac fibrosis [3.95 ± 0.62% (WT) vs. 1.41 ± 0.46% (Irf3(-/-)/Bcl2l12(-/-)); P<0.01] and accompanied reduction in left ventricle end-diastolic dimension [2.89 ± 0.10 mm (WT) vs. 3.51 ± 0.15 mm (Irf3(-/-)/Bcl2l12(-/-)); P=0.012] are strongly suppressed in Irf3(-/-)/Bcl2l12(-/-) mice, whereas hypertrophy still develops. Further, we provide evidence for the activation of IRF3 by ANG II signaling in mouse cardiac fibroblasts. Unlike the activation of IRF3 by innate immune receptors, IRF3 activation by ANG II is unique in that it is activated through the canonical ERK signaling pathway. Thus, our present study reveals a hitherto unrecognized function of IRF3 in cardiac remodeling, providing new insight into the progression of hypertension-induced cardiac pathogenesis.

Restraint stress induces connexin-43 translocation via α-adrenoceptors in rat heart.

BACKGROUND: Immobilization (IMO) confers emotional stress in animals and humans. It was recently reported that IMO in rats induced translocation of connexin-43 (Cx43) to gap junctions (GJs) and attenuated arrhythmogenesis with GJ inhibition, and Cx43 translocation in the ischemic heart was also shown. Few reports show the contribution of adrenoceptors to Cx43 upregulation in cardiomyocytes, but the involvement of adrenoceptors and ischemia in Cx43 translocation in IMO remains elusive. METHODS AND RESULTS: Male Sprague-Dawley rats underwent IMO and the ventricular distribution of Cx43 was examined by western blotting. IMO induced translocation of Cx43 to the GJ-enriched membrane fraction, with a peak at 60min. The IMO-induced Cx43 translocation was inhibited by pretreatment with the α(1)-adrenoceptor blockers, prazosin (1mg/kg, PO) and bunazosin (4mg/kg, PO), but not with either the ß(1)-blocker, metoprolol (10mg/kg, IP), or the ß(1+2)-blocker, propranolol (1mg/kg, PO). The translocation was inhibited by the nitric oxide, donor isosorbide dinitrate (100µg·kg(-1)·min(-1), IV), possibly through sympathetic inhibition. Hypoxia inducible factor-1α was not redistributed by IMO. The ß-blockers, but not the α-blockers, inhibited the premature ventricular contractions (PVCs) induced by IMO. CONCLUSIONS: Translocation of Cx43 to the GJ-enriched fraction occurs via the α(1)-adrenoceptor pathway, independently of ischemia. The ß-adrenoceptor pathway contributes to the inducing of PVCs in IMO.

Connexin-43 redistribution and gap junction activation during forced restraint protects against sudden arrhythmic death in rats.

BACKGROUND: Connexin-43 (Cx43) expression is reduced or redistributed in heart disease. Restraint or other emotional stressors might cause sudden death in persons with such diseases, but the mechanism of death and its connection to Cx43 during restraint remain unknown. Whether Cx43 distribution or gap junction (GJ) function during restraint is involved in sudden arrhythmic death in rats is addressed in this study. METHODS AND RESULTS: Male Sprague-Dawley rats underwent immobilization (IMO), and individual electrocardiographic responses were monitored by telemetry. Heart sections were used to examine ventricular Cx43 distribution, and GJ intercellular communication (GJIC) activity was assessed using a dye-transfer assay. IMO induced the translocation of Cx43 into to the GJ-rich fraction, with a peak at 60 min. During IMO, Cx43 immunofluorescence was enhanced at intercalated discs, in association with GJIC activation, and premature ventricular contractions (PVCs) increased. In the presence of the GJ inhibitor, carbenoxolone (0.25 mg.kg(-1).h(-1)), IMO induced lethal ventricular tachycardia or fibrillation in 21.7% of rats, in association with QRS prolongation and increased PVCs. CONCLUSIONS: IMO causes Cx43 translocation to intercalated discs, thereby reducing vulnerability to lethal arrhythmias via enhancing GJ coupling.

Autopsy report on central pontine myelinolysis triggered by vomiting associated with digoxin intoxication.

An 87-year-old male, prescribed digoxin and furosemide for congestive heart failure and Alzheimer disease, had dehydration and anemia due to poor food intake and hemorrhagic cystitis. Repeated vomiting due to an upper respiratory infection caused disturbance of consciousness and hypotension. The patient was admitted to hospital and diagnosed with digoxin intoxication and hypernatremia. The serum sodium (Na(+)) level was corrected, but the patient died 4 days after admission following uncontrollable seizure. A histologic examination after an autopsy revealed characteristic findings of central pontine myelinolysis (CPM). This is the first autopsy report on CPM triggered by vomiting in association with digoxin administration.

Kruppel-like factor 5 causes cartilage degradation through transactivation of matrix metalloproteinase 9.

Although degradation of cartilage matrix has been suggested to be a rate-limiting step for endochondral ossification during skeletal development, little is known about the transcriptional regulation. This study investigated the involvement of KLF5 (Krüppel-like factor 5), an Sp/KLF family member, in the skeletal development. KLF5 was expressed in chondrocytes and osteoblasts but not in osteoclasts. The heterozygous deficient (KLF5+/-) mice exhibited skeletal growth retardation in the perinatal period. Although chondrocyte proliferation and differentiation were normal, cartilage matrix degradation was impaired in KLF5+/- mice, causing delay in replacement of cartilage with bone at the primary ossification center in the embryonic limbs and elongation of hypertrophic chondrocyte layer in the neonatal growth plates. Microarray analyses identified MMP9 (matrix metalloproteinase 9) as a transcriptional target, since it was strongly up-regulated by adenoviral transfection of KLF5 in chondrogenic cell line OUMS27. The KLF5 overexpression caused gelatin degradation by stimulating promoter activity of MMP9 without affecting chondrocyte differentiation or vascular endothelial growth factor expression in the culture of chondrogenic cells; however, in osteoclast precursors, it affected neither MMP9 expression nor osteoclastic differentiation. KLF5 dysfunction by genetic heterodeficiency or RNA interference was confirmed to cause reduction of MMP9 expression in cultured chondrogenic cells. MMP9 expression was decreased in the limbs of KLF5+/- embryos, which was correlated with suppression of matrix degradation, calcification, and vascularization. We conclude that KLF5 causes cartilage matrix degradation through transcriptional induction of MMP9, providing the first evidence that transcriptional regulation of a proteinase contributes to endochondral ossification and skeletal development.

DeltaEF1 mediates TGF-beta signaling in vascular smooth muscle cell differentiation.

Alteration in the differentiated state of smooth muscle cells (SMCs) is known to be integral to vascular development and the pathogenesis of vascular disease. However, it is still largely unknown how environmental cues translate into transcriptional control of SMC genes. We found that deltaEF1 is upregulated during SMC differentiation and selectively transactivates the promoters of SMC differentiation marker genes, SM alpha-actin and SM myosin heavy chain (SM-MHC). DeltaEF1 physically interacts with SRF and Smad3, resulting in a synergistic activation of SM alpha-actin promoter. Chromatin immunoprecipitation assays and knockdown experiments showed that deltaEF1 is involved in the control of the SMC differentiation programs induced by TGF-beta signaling. Overexpression of deltaEF1 inhibited neointima formation and promoted SMC differentiation, whereas heterozygous deltaEF1 knockout mice exhibited exaggerated neointima formation. It thus appears deltaEF1 mediates SMC differentiation via interaction with SRF and Smad3 during development and in vascular disease.

Krüppel-like transcription factor KLF5 is a key regulator of adipocyte differentiation.

Krüppel-like factor 5 (KLF5) is a zinc-finger transcription factor known to play a pivotal role in the pathogenesis of cardiovascular disease. Here, we show that neonatal heterozygous KLF5 knockout mice exhibit a marked deficiency in white adipose tissue development, suggesting that KLF5 is also required for adipogenesis. In 3T3-L1 preadipocytes, KLF5 expression was induced at an early stage of differentiation, and this was followed by expression of PPARgamma2. Constitutive overexpression of dominant-negative KLF5 inhibited adipocyte differentiation, whereas overexpression of wild-type KLF5 induced differentiation even without hormonal stimulation. Moreover, embryonic fibroblasts obtained from KLF5+/- mice showed much attenuated adipocyte differentiation, confirming the key role played by KLF5 in adipocyte differentiation. KLF5 expression is induced by C/EBPbeta and delta. KLF5, in turn, acts in concert with C/EBPbeta/delta to activate the PPARgamma2 promoter. This study establishes KLF5 as a key component of the transcription factor network controlling adipocyte differentiation.

A common Ile 823 Met variant of ATP-binding cassette transporter A1 gene (ABCA1) alters high density lipoprotein cholesterol level in Japanese population.

Recently, variants in ATP-binding cassette transporter A1 (ABCA1) were demonstrated to be associated with increased level of high density lipoprotein cholesterol (HDL-C) and decreased risk of coronary artery disease (CAD) in Caucasians. However, this is not universally applicable due to the ethnic or environmental differences. In this context, to clarify the effect of ABCA1 in Japanese, we evaluated the phenotypic effects of I/M 823 and R/K 219 variants on the plasma level of HDL-C in 410 patients recruited in our hospital. Subjects with M 823 allele had significantly higher level of HDL-C than those without M823 allele (49.0+/-15.1 vs. 44.9+/-11.5 mg/dl, respectively, P<0.05). This statistical significance did not change even after multiple regression analysis. In contrast, there was no difference in HDL-C level among the genotypes in R/K 219 polymorphism. Further, in our study population an inverse relationship was shown to exist between HDL-C level and incidence of CAD. However, no positive association was observed between those variants and susceptibility to CAD. In this study, we provide evidence that I/M 823 variant, not R/K 219 variant, in ABCA1 is one of the determinants of HDL-C level, suggesting the importance of this gene on lipid metabolism in Japanese.

[Assessment of coronary calcification by computed tomography inclusive of 3DCT].

Coronary artheroclerosis in diabetes patients can be divided into 2 phases, one is seen in the early phase of diabetes or insulin resistance syndrome as unstable plaque with lipid-rich core, thinner fibrous caps and small dose or a lack of calcification and the other in the late or advanced stage of diabetes is hard and stable plaque with much fibrous protein and calcification which extends from truncal to peripheral areas. In diabetic patients in the late stage, coronary accidents occur as the chronic multiple vessel diseases with a lot of calcification, while in the early stage of diabetes vasospastic angina and acute coronary syndrome with less calcification tends to occur. We can find out the coronary calcification by EBCT or 3DCT easily which is characteristic in patients of diabetes complicated with coronary artery disease and in the early stage the stenosis of left truncal artery or large vessels of LAD can be detectable by 3DCT.

Effects of carvedilol on plasma levels of interleukin-6 and tumor necrosis factor-alpha in nine patients with dilated cardiomyopathy.

OBJECTIVES: Whether beta-blocker therapy changes the circulating levels of cytokines as congestive heart failure improves remains uncertain. METHODS: Nine patients with idiopathic dilated cardiomyopathy, who had previously received conventional treatment and were classified as New York Heart Association (NYHA) functional class II, received carvedilol by stepwise dose increase up to 20 mg daily, and the plasma interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels were measured. RESULTS: IL-6 was significantly reduced from 0.80 +/- 0.49 pg/ml before therapy to 0.21 +/- 0.08 pg/ml after carvedilol was increased to 20 mg daily (p < 0.05). Moreover, IL-6 level had already decreased significantly compared to the baseline when the dose of carvedilol had reached 10 mg daily (0.28 +/- 0.12 pg/ml, p < 0.05). TNF-alpha levels did not change significantly. CONCLUSIONS: These results demonstrate that IL-6 concentration is significantly decreased by beta-blocker therapy. The efficacy for heart failure may be related to the change of IL-6 concentration.