Exosomal miR206 Secreted From Growing Muscle Promotes Angiogenic Response in Endothelial Cells.

BACKGROUND: Resistance exercise is beneficial in patients with lower extremity arterial disease. Muscle-derived exosomes contain many types of signaling molecules, including microRNAs (miRNAs). Here, we tested the hypothesis that exosomal miRNAs secreted by growing muscles promote an angiogenic response in endothelial cells (ECs).Methods and Results: Skeletal muscle-specific conditional Akt1 transgenic (Akt1-TG) mice, in which skeletal muscle growth can be induced were used as a model of resistance training. Remarkable skeletal muscle growth was observed in mice 2 weeks after gene activation. The protein amount in exosomes secreted by growing muscles did not differ between Akt1-TG and control mice. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway frequency analysis of 4,665 target genes, identified using an miRNA array miRNAs, revealed a significant increase in Akt and its downstream signaling pathway genes. Among the upregulated miRNAs, miR1, miR133, and miR206 were significantly upregulated in the serum of Akt1-TG mice. miR206 was also increased in insulin-like growth factor (IGF)-1-stimulated hypertrophied myotubes. Exogenous supplementation of exosomal miR206 to human umbilical vein ECs promoted angiogenesis, as assessed using the spheroid assay, and increased the expression of angiogenesis-related transcripts. CONCLUSIONS: Exosomal miR206 is upregulated in the blood of Akt1-TG mice and in IGF-stimulated cultured myotubes. Exogenous supplementation of miR206 promoted an angiogenic response in ECs. Our data suggest that miR206 secreted from growing muscles acts on ECs and promotes angiogenesis.

ß-Blockers are associated with increased B-type natriuretic peptide levels differently in men and women in heart failure with preserved ejection fraction.

ß-Blocker (BB) use is a mainstay for the treatment of heart failure (HF) with reduced ejection fraction (HFrEF), whereas its efficacy for heart failure with preserved ejection fraction (HFpEF) remains controversial. Women outnumber men in HFpEF, whereas men outnumber women in HFrEF. Plasma B-type natriuretic peptide (BNP) is established as a biomarker for HF. We examined whether BB use is associated with plasma BNP levels differently in men and women with HFpEF. The study subjects comprised 721 patients with HFpEF [left ventricular ejection fraction (LVEF) ≥ 50%] (184 men, mean age 78.2 ± 9.2 yr and 537 women, mean age 83.1 ± 8.8 yr), 179 on BB (66 men and 113 women) and 542 no BB (118 men and 424 women), 583 in sinus rhythm (SR) and 138 in atrial fibrillation (AF). A multivariable logistic regression test was used. Plasma BNP levels were higher (P = 0.0005), systolic blood pressure and LVEF lower (P = 0.0003, and P = 0.0059, respectively) on BBs than on no BBs in women, whereas in men, plasma BNP levels, systolic blood pressure, and LVEF were not altered significantly (P = 0.0849, P = 0.9129, and P = 0.4718, respectively) on BBs compared with no BBs in patients with SR. Multivariable logistic regression analysis revealed that BB use and women were a positive and a negative predictor for high BNP levels (P = 0.003 and P = 0.032, respectively) in SR but not in AF. BB use was associated with high-plasma BNP levels and lower LVEF in women but not in men with HFpEF and SR, suggesting that the pathogenesis and treatment of HFpEF may differ in men and women in SR.NEW & NOTEWORTHY Pathogenesis and treatment for heart failure with preserved ejection fraction (HFpEF) may differ in men and women in sinus rhythm (SR).

East Asian variant aldehyde dehydrogenase type 2 genotype exacerbates ischemia/reperfusion injury with ST-elevation myocardial infarction in men: possible sex differences.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) detoxifies toxic aldehydes generated during ischemia/reperfusion (I/R) injury in ST-elevation myocardial infarction (STEMI). The deficient variant ALDH2 genotype (ALDH2*2) is prevalent among East Asians. Whether ALDH2*2 exacerbates I/R injury of in patients with STEMI is not known. The study subjects comprised 218 Japanese patients with STEMI (158 men and 60 women, mean age 67.9 ± 11.9) who underwent successful percutaneous coronary intervention. Of these, 120 (55.0%) were the carriers of variant ALDH2*2 and 98 (45.0%) those of wild ALDH2*1/*1 on genotyping. There were no differences in clinical characteristics between the ALDH2*2 and ALDH2*1/*1 group except lower alcohol habit (14.2% vs 46.3%, P < 0.001) in the ALDH2*2 group. The peak plasma levels of creatine phosphokinase myocardial binding (CKMB), a marker of myocardial injury, however, were significantly higher in the patients with ALDH2*2 than in those with ALDH2*1/*1 [a median 275.0 (175.8-407.5) vs 177.5 (126.9-344.3) U/L, P = 0.001] among men but not among women (P = 0.811). There was a significant interaction between men (male sex) and ALDH2*2 for I/R injury (χ2 = 4.425, P = 0.040). The variant ALDH2*2 was associated with more severe I/R injury than the wild ALDH2*1/*1 in STEMI patients in men with possible sex differences.

Sirt7 Deficiency Attenuates Neointimal Formation Following Vascular Injury by Modulating Vascular Smooth Muscle Cell Proliferation.

BACKGROUND: Sirt7 is a recently identified sirtuin and has important roles in various pathological conditions, including cancer progression and metabolic disorders. It has previously been reported that Sirt7 is a key molecule in acute myocardial wound healing and pressure overload-induced cardiac hypertrophy. In this study, the role of Sirt7 in neointimal formation after vascular injury is investigated.Methods and Results:Systemic (Sirt7-/-) and smooth muscle cell-specific Sirt7-deficient mice were subjected to femoral artery wire injury. Primary vascular smooth muscle cells (VSMCs) were isolated from the aorta of wild type (WT) and Sirt7-/-mice and their capacity for cell proliferation and migration was compared. Sirt7 expression was increased in vascular tissue at the sites of injury. Sirt7-/-mice demonstrated significant reduction in neointimal formation compared to WT mice. In vitro, Sirt7 deficiency attenuated the proliferation of serum-induced VSMCs. Serum stimulation-induced upregulation of cyclins and cyclin-dependent-kinase 2 (CDK2) was significantly attenuated in VSMCs of Sirt7-/-compared with WT mice. These changes were accompanied by enhanced expression of the microRNA 290-295 cluster, the translational negative regulator of CDK2, in VSMCs of Sirt7-/-mice. It was confirmed that smooth muscle cell-specific Sirt7-deficient mice showed significant reduction in neointima compared with control mice. CONCLUSIONS: Sirt7 deficiency attenuates neointimal formation after vascular injury. Given the predominant role in vascular neointimal formation, Sirt7 is a potentially suitable target for treatment of vascular diseases.

Akt1-Mediated Muscle Growth Promotes Blood Flow Recovery After Hindlimb Ischemia by Enhancing Heme Oxygenase-1 in Neighboring Cells.

BACKGROUND: Resistance exercise has beneficial effects for patients with peripheral arterial diseases. The hypothesis that muscle growth promotes angiogenesis by interacting with neighboring cells in ischemic lesions was assessed. Methods and Results: Skeletal muscle-specific inducible Akt1 transgenic (Akt1-TG) mice that induce growth of functional skeletal muscles as a model of resistance training were used. Proteomics analysis identified significant upregulation of heme oxigenase-1 (HO-1) in muscle tissue in Akt1-TG mice compared with control mice. Blood flow recovery after hindlimb ischemia was significantly increased in Akt1-TG mice compared with control mice. Enhanced blood flow and capillary density in Akt1-TG mice were completely abolished by the HO-1 inhibitor, Tin-mesoporphyrin. Immunohistochemistry showed that HO-1 expression was not increased in muscle cells, but it was increased in macrophages and endothelial cells. Consistent with these findings, blood flow recovery after hindlimb ischemia was similar between control mice and skeletal muscle-specific HO-1-knockout mice. Adenoviral-mediated overexpression of Akt1 did not increase HO-1 protein expression in C2C12 myotubes; however, the conditioned medium from Akt1-overexpressing C2C12 myotubes increased HO-1 expression in endothelial cells. Cytokine array demonstrated that a panel of cytokine secretion was upregulated in Akt1-overexpressing C2C12 cells, suggesting paracrine interaction between muscle cells and endothelial cells and macrophages. CONCLUSIONS: Akt1-mediated muscle growth improves blood flow recovery after hindlimb ischemia by enhancing HO-1 expression in neighboring cells.

Identification and Assessment of Cardiac Amyloidosis by Myocardial Strain Analysis of Cardiac Magnetic Resonance Imaging.

BACKGROUND: We explored the usefulness of myocardial strain analysis on cardiac magnetic resonance imaging (CMR) scans for the identification of cardiac amyloidosis.Methods and Results:The 61 patients with systemic amyloidosis underwent 3.0-T CMR, including CMR tagging and late-gadolinium enhanced (LGE) imaging. The circumferential strain (CS) of LGE-positive and LGE-negative patients was measured on midventricular short-axis images and compared. Logistic regression modeling of CMR parameters was performed to detect patients with LGE-positive cardiac amyloidosis. Of the 61 patients with systemic amyloidosis 48 were LGE-positive and 13 were LGE-negative. The peak CS was significantly lower in the LGE-positive than in the LGE-negative patients (-9.5±2.3 vs. -13.3±1.4%, P<0.01). The variability in the peak CS time was significantly greater in the LGE-positive than in the LGE-negative patients (46.1±24.5 vs. 21.2±20.1 ms, P<0.01). The peak CS significantly correlated with clinical biomarkers. The sensitivity, specificity, and accuracy of the diagnostic model using CS parameters for the identification of LGE-positive amyloidosis were 93.8%, 76.9%, and 90.2%, respectively. CONCLUSIONS: Myocardial strain analysis by CMR helped detect LGE-positive amyloidosis without the need for contrast medium. The peak CS and variability in the peak CS time may correlate with the severity of cardiac amyloid deposition and may be more sensitive than LGE imaging for the detection of early cardiac disease in patients with amyloidosis.

Reduced trans-mitral A-wave velocity predicts the presence of wild-type transthyretin amyloidosis in elderly patients with left ventricular hypertrophy.

Wild-type transthyretin amyloidosis (ATTRwt) is often overlooked in elderly patients with left ventricular hypertrophy (LVH). Impaired atrial function, in addition to ventricular diastolic dysfunction, is one of the hallmarks of cardiac amyloidosis. Here, we assessed the hypothesis that atrial function evaluated by A-velocity in pulse Doppler echocardiography is useful to differentiate ATTRwt in elderly patients with LVH. We analyzed 133 consecutive patients who underwent tissue biopsy to rule out infiltrative cardiomyopathy in our institute. We excluded patients younger than 50 years, without LVH (LV thickness was less than 12 mm), with other types of cardiac amyloidosis and patients with chronic atrial fibrillation, and analyzed remaining 51 patients (ATTRwt: 16, non-ATTRwt: 35). ATTRwt patients were significantly older and had advanced heart failure compared with non-ATTRwt group. In echocardiography, E/A, E/e', and relative wall thickness was significantly higher in ATTRwt group than non-ATTRwt group. A-velocity was significantly decreased in ATTRWT group compared with non-ATTRwt group (40.8 ± 20.8 vs. 78.7 ± 28.2 cm/s, p = 0.0001). Multivariate logistic analysis using eight forced inclusion models identified trans-mitral Doppler A-wave velocity was more significant factor of cardiac amyloidosis in ATTRwt. In receiver operating characteristic (ROC) analysis, the area under the curve (AUC) for A-wave velocity in discrimination between ATTRwt and non-ATTRwt were 0.86 (CI 0.76-0.96, p < 0.001). The cut-off value was 62.5 cm/s, and it yielded the best combination of sensitivity (69.7%) and specificity (87.5%) for prediction of amyloidosis. We concluded that reduced A-velocity predicts the presence of ATTRwt in elderly patients with LVH in sinus rhythm.

Deterioration of Phosphate Homeostasis Is a Trigger for Cardiac Afterload　- Clinical Importance of Fibroblast Growth Factor 23 for Accelerated Aging.

Background: After the discovery of the Klotho gene, phosphate came into focus as a pathogenetic aging agent. Phosphate homeostasis is controlled by phosphate-regulating hormones: fibroblast growth factor 23 (FGF23), vitamin D3, and parathyroid hormone. This study investigated the relationship between the deterioration in phosphate homeostasis and arterial stiffness by measuring serum FGF23 concentrations. Methods and Results: The study subjects comprised 82 hospitalized patients (31 males, 51 females; mean [±SD] age 78.6±10.5 years). All patients underwent chest computed tomography, measurement of central blood pressure (BP), and blood chemistry tests. Arterial calcification and/or stiffness was evaluated using the Agatston calcification score (ACS) and pulse wave velocity (PWV). PWV was significantly correlated with age (t=23.47, P<0.0001), estimated glomerular filtration rate (eGFR; t=-4.40, P<0.0001), and ACS (t=4.36, P<0.0001). Serum FGF23 concentrations were significantly correlated with age (t=2.52, P=0.014), eGFR (t=-3.37, P<0.001), serum inorganic phosphorus concentrations (t=3.49, P<0.001), serum vitamin D3 concentrations (t=-4.57, P<0.001), ACS (t=2.30, P=0.025), augmentation pressure (t=2.48, P=0.015), central systolic BP (t=2.00, P=0.049), plasma B-type natriuretic peptide (BNP) concentrations (t=3.48, P<0.001), and PWV (t=2.99, P=0.004). PWV was positively related to augmentation pressure (t=4.09, P<0.001), central systolic BP (t=3.13, P=0.002), and plasma BNP concentrations (t=3.54, P<0.001). Conclusions: This study shows that the increase in serum FGF23 concentrations reflects deterioration of phosphate homeostasis and is an important predictor for arterial stiffness, which intensifies cardiac afterload.

CORRIGENDUM: Deterioration of Phosphate Homeostasis Is a Trigger for Cardiac Afterload　- Clinical Importance of Fibroblast Growth Factor 23 for Accelerated Aging.

[This corrects the article DOI: 10.1253/circrep.CR-22-0124.].

HE4 Predicts Progressive Fibrosis and Cardiovascular Events in Patients With Dilated Cardiomyopathy.

Background Cardiac fibrosis plays a crucial role in the pathogenesis of dilated cardiomyopathy (DCM). HE4 (human epididymis protein 4) is a secretory protein expressed in activated fibroblasts that exacerbates tissue fibrosis. In the present study, we investigated the clinical utility of HE4 measurement in patients with DCM and its pathophysiological role in preclinical experiments in vivo and in vitro. Methods and Results We measured serum HE4 levels of 87 patients with DCM. Endomyocardial biopsy expressed severe fibrosis only in the high HE4 group (P<0.0001). Echocardiography showed that left ventricular end-diastolic diameter tends to decrease over time (58±7.3 to 51±6.6 mm; P<0.0001) in the low HE4 group (<59.65 pmol/L [median value]). HE4 was significantly associated with risk reduction of mortality and cardiovascular hospitalization in multivariate Cox model. In vivo, HE4 was highly expressed in kidney and lung tissue of mouse, and scarcely expressed in heart. In genetically induced DCM mouse model, HE4 expression increased in kidney but not in heart and lung. In vitro, supernatant from HE4-transfected human embryonic kidney 293T cells enhanced transdifferentiation of rat neonatal fibroblasts and increased expression of fibrosis-related genes, and this was accompanied by the activation of extracellular signal-regulated kinase signaling in cardiac fibroblasts. Treatment with an inhibitor of upstream signal of extracellular signal-regulated kinase or a neutralizing HE4 antibody canceled the profibrotic properties of HE4. Conclusions HE4 functions as a secretory factor, activating cardiac fibroblasts, thereby inducing cardiac interstitial fibrosis. HE4 could be a promising biomarker for assessing ongoing fibrosis and a novel therapeutic target in DCM. Registration URL: https://upload.umin.ac.jp/cgi-open-bin/ctr; Unique identifier: UMIN000043062.

Murine neonatal ketogenesis preserves mitochondrial energetics by preventing protein hyperacetylation.

Ketone bodies are generated in the liver and allow for the maintenance of systemic caloric and energy homeostasis during fasting and caloric restriction. It has previously been demonstrated that neonatal ketogenesis is activated independently of starvation. However, the role of ketogenesis during the perinatal period remains unclear. Here, we show that neonatal ketogenesis plays a protective role in mitochondrial function. We generated a mouse model of insufficient ketogenesis by disrupting the rate-limiting hydroxymethylglutaryl-CoA synthase 2 enzyme gene (Hmgcs2). Hmgcs2 knockout (KO) neonates develop microvesicular steatosis within a few days of birth. Electron microscopic analysis and metabolite profiling indicate a restricted energy production capacity and accumulation of acetyl-CoA in Hmgcs2 KO mice. Furthermore, acetylome analysis of Hmgcs2 KO cells revealed enhanced acetylation of mitochondrial proteins. These findings suggest that neonatal ketogenesis protects the energy-producing capacity of mitochondria by preventing the hyperacetylation of mitochondrial proteins.

Cardiomyocyte Sirt (Sirtuin) 7 Ameliorates Stress-Induced Cardiac Hypertrophy by Interacting With and Deacetylating GATA4.

Sirt (Sirtuin) 7, the most recently identified mammalian sirtuin, has been shown to contribute to appropriate wound healing processes after acute cardiovascular insult. However, its role in the development of cardiac remodeling after pressure overload is unclear. Cardiomyocyte-specific Sirt7-knockout and control mice were subjected to pressure overload induced by transverse aortic constriction. Cardiac hypertrophy and functions were then examined in these mice. Sirt7 protein expression was increased in myocardial tissue after pressure overload. Transverse aortic constriction-induced increases in heart weight/tibial length were significantly augmented in cardiomyocyte-specific Sirt7-knockout mice compared with those of control mice. Histological analysis showed that the cardiomyocyte cross-sectional area and fibrosis area were significantly larger in cardiomyocyte-specific Sirt7-deficient mice. Cardiac contractile functions were markedly decreased in cardiomyocyte-specific Sirt7-deficient mice. Mechanistically, we found that Sirt7 interacted directly with GATA4 and that the exacerbation of phenylephrine-induced cardiac hypertrophy by Sirt7 knockdown was decreased by GATA4 knockdown. Sirt7 deacetylated GATA4 in cardiomyocytes and regulated its transcriptional activity. Interestingly, we demonstrated that treatment with nicotinamide mononucleotide, a known key NAD+ intermediate, ameliorated agonist-induced cardiac hypertrophies in a Sirt7-dependent manner in vitro. Sirt7 deficiency in cardiomyocytes promotes cardiomyocyte hypertrophy in response to pressure overload. Sirt7 exerts its antihypertrophic effect by interacting with and promoting deacetylation of GATA4.

Non-invasive testing for sarcopenia predicts future cardiovascular events in patients with chronic kidney disease.

BACKGROUND: Sarcopenia is frequently observed and associated with poor outcomes in patients with chronic kidney disease (CKD). A simple screening test for sarcopenia using age, grip strength, and calf circumference was recently developed. However, the clinical utility of this sarcopenia score in patients with CKD remains unclear. METHODS AND RESULTS: We calculated the sarcopenia score of 265 patients with CKD and followed the patients for cardiovascular events. The endpoint of this study was the composite of cardiovascular hospitalization and total mortality. We divided all participants into high (n = 166) and low (n = 99) sarcopenia score groups using a simple scoring system. Patients in the high sarcopenia score group showed significantly higher plasma B-type natriuretic peptide (BNP) levels than those in the low sarcopenia score group (median: 103.1, interquartile range: 46.3-310.0 vs. 46.7, 18.0-91.8 pg/mL; p < 0.0001). The Kaplan-Meier curve revealed that the risk of cardiovascular events was significantly greater in the high sarcopenia score group (log-rank test: p < 0.0001), even after potential confounding factors were corrected using propensity score matching. Multivariate Cox hazard analysis identified a high sarcopenia score (hazard ratio: 3.04, 95% confidence interval: 1.45-6.38, p = 0.003) as an independent predictor of the primary endpoints. Furthermore, the combination of a high sarcopenia score and high BNP level identified patients with a significantly higher probability of future events (p < 0.0001). CONCLUSIONS: This study demonstrates that this simple screening score for sarcopenia could be a useful tool for estimating the future adverse event risk in patients with CKD.