MicroRNA-33 Controls Adaptive Fibrotic Response in the Remodeling Heart by Preserving Lipid Raft Cholesterol.

RATIONALE: Heart failure and atherosclerosis share the underlying mechanisms of chronic inflammation followed by fibrosis. A highly conserved microRNA (miR), miR-33, is considered as a potential therapeutic target for atherosclerosis because it regulates lipid metabolism and inflammation. However, the role of miR-33 in heart failure remains to be elucidated. OBJECTIVE: To clarify the role of miR-33 involved in heart failure. METHODS AND RESULTS: We first investigated the expression levels of miR-33a/b in human cardiac tissue samples with dilated cardiomyopathy. Increased expression of miR-33a was associated with improving hemodynamic parameters. To clarify the role of miR-33 in remodeling hearts, we investigated the responses to pressure overload by transverse aortic constriction in miR-33-deficient (knockout [KO]) mice. When mice were subjected to transverse aortic constriction, miR-33 expression levels were significantly upregulated in wild-type left ventricles. There was no difference in hypertrophic responses between wild-type and miR-33KO hearts, whereas cardiac fibrosis was ameliorated in miR-33KO hearts compared with wild-type hearts. Despite the ameliorated cardiac fibrosis, miR-33KO mice showed impaired systolic function after transverse aortic constriction. We also found that cardiac fibroblasts were mainly responsible for miR-33 expression in the heart. Deficiency of miR-33 impaired cardiac fibroblast proliferation, which was considered to be caused by altered lipid raft cholesterol content. Moreover, cardiac fibroblast-specific miR-33-deficient mice also showed decreased cardiac fibrosis induced by transverse aortic constriction as systemic miR-33KO mice. CONCLUSION: Our results demonstrate that miR-33 is involved in cardiac remodeling, and it preserves lipid raft cholesterol content in fibroblasts and maintains adaptive fibrotic responses in the remodeling heart.

Elevation of Derivatives of Reactive Oxygen Metabolites Elevated in Young "Disaster Responders" in Hypertension due to Great East Japan Earthquake.

There have been very few studies on serum biomarkers associated with hypertension in disaster situations. We assessed biomarkers associated with disaster-related hypertension (DRH) due to the Great East Japan Earthquake of March 2011.We collected blood samples from members of the Japan Self Defense Forces (JSDF) (n = 77) after completing disaster relief operations. We divided them into two groups based on systolic blood pressure. We defined DRH as either systolic blood pressure greater than 140 mmHg or diastolic blood pressure greater than 90 mmHg at the time of completing missions.In subjects with DRH, the mean blood pressure was 143.5 ± 5.0/99.5 ± 2.4 mmHg. Height and body weight measurements were slightly greater in the DRH group but the differences were not significant, and age was significantly higher in the DRH group. There were no differences in serum biochemical tests including metabolic markers, sulfur-containing amino acids, and cytokines. Among nitric oxide-related amino acids, asymmetric dimethylarginine (ADMA) was lower in the DRH group than in the normotension group (0.40 ± 0.02 versus 0.31 ± 0.02 µmol/L P = 0.04). The serum oxidative stress metabolite levels (d-ROMs; indicators of active oxygen metabolite products) were significantly higher in the DRH group (273.6 ± 6.08 versus 313.5 ± 13.7 U.CARR P = 0.016). Using multivariable regression analysis, d-ROMs levels were particularly predictive for DRH.Oxidative stress is associated with DRH in responders to the disaster of the Great East Japan Earthquake.

Rationale and protocol of the LAQUA-HF trial: a factorial randomised controlled trial evaluating the effects of neurohormonal and diuretic agents on health-status reported outcomes in heart failure patients.

INTRODUCTION: The current guidelines strongly recommend early initiation of multiple classes of cardioprotective drugs for patients with heart failure with reduced ejection fraction to improve prognosis and health status. However, evidence on the optimal sequencing of approved drugs is scarce, highlighting the importance of individualised treatment plans. Registry data indicate that only a portion of these patients can tolerate all four recommended classes, underscoring the need to establish the favoured sequence when using these drugs. Additionally, the choice between long-acting and short-acting loop diuretics in the present era remains uncertain. This is particularly relevant given the frequent use of angiotensin receptor-neprilysin inhibitor and sodium-glucose cotransporter 2 inhibitor, both of which potentiate natriuretic effects. METHODS AND ANALYSIS: In a prospective, randomised, open-label, blinded endpoint method, LAQUA-HF (Long-acting vs short-acting diuretics and neurohormonal Agents on patients' QUAlity-of-life in Heart Failure patients) will be a 2×2 factorial design, with a total of 240 patients randomised to sacubitril/valsartan versus dapagliflozin and torsemide versus furosemide in a 1:1 ratio. Most enrolment sites have participated in an ongoing observational registry for consecutive patients hospitalised for heart failure involved dedicated study coordinators, and used the same framework to enrol patients. The primary endpoint is the change in patients' health status over 6 months, defined by the Kansas City Cardiomyopathy Questionnaire. Additionally, clinical benefit at 6 months defined as a hierarchical composite endpoint will be assessed by the win ratio as the secondary endpoint. ETHICS AND DISSEMINATION: The medical ethics committee Keio University in Japan has approved this trial. All participants provide written informed consent prior to study entry. The results of this trial will be disseminated in one main paper and additional papers on secondary endpoints and subgroup analyses. TRIAL REGISTRATION NUMBER: UMIN000045229.

Causal relation of tricuspid regurgitation for heart failure outcomes: a mediation analysis of echocardiographic predictors.

Aims: Although significant tricuspid regurgitation (TR) is critically associated with heart failure (HF) prognosis, the predictors for large TR impact on HF outcomes remain unknown. This study aimed to identify echocardiographic predictors for a causal relation of TR to HF outcomes. Methods and results: In a retrospective, acute HF cohort of 462 patients, multivariate logistic regression analysis was performed to determine subgroups with strong association of greater-than-moderate TR with HF readmission or cardiovascular death in a year. We then conducted causal mediation analysis according to persistent atrial fibrillation (Af) or mitral regurgitation (MR) to identify the echocardiographic predictors. The association of TR with HF outcomes was prominent in subgroups of females, with Af, the enlarged indexed tricuspid annular diameter (TADi) or right atrial area, or within certain ranges of the left ventricular ejection fraction, indexed right ventricular end-systolic area, or fractional area change (FAC). Causal mediation analysis found that the TR impact was significant in patients with Af. Furthermore, combination of TADi ≥2.1 cm/m2 and FAC ≥30%, which accounted for half of TR patients, predicted a much larger TR impact irrespective of Af and MR. Its prediction ability was superior to that of the modified Model for End-stage Liver Disease score. Conclusion: The causal impact and burden of TR on HF outcomes was significant in patients with Af, and combining TADi ≥2.1 cm/m2 with FAC ≥30% could provide superior echocardiographic prediction of larger TR impact in HF patients.

Combinations of cardiac and non-cardiac predictors for prognoses in patients with acute heart failure.

AIMS: In contemporary heart failure (HF) practice, prognostic value for combinations of cardiac and non-cardiac predictors remains poorly understood. We analysed the combinatorial predictors of outcomes in acute HF patients. METHODS AND RESULTS: This longitudinal cohort study included consecutive patients admitted for acute decompensated HF between April 2015 and March 2018 in an urban hospital. The main outcomes are HF readmission within 6 months after discharge or all-cause death. A total of 451 patients with 662 admissions were enrolled and the data including frailty and echocardiographic parameters were analysed by multivariate and matched cohort analyses. The mean age of the patients was 76.8 years. We constructed a multi-frailty index (MFI) ranging from 0 to 3 points as a composite of non-cardiac comorbidities and biopsychosocial frailty. In matched cohort of patients with ejection fraction ≧50% (HFpEF), MFI ≧1, pulmonary hypertension (PH; peak flow velocity of tricuspid regurgitation ≧2.9 m/s by echocardiography), and pancytopenia at discharge were strong predictors of HF readmission [odds ratios (ORs), 4.33, 2.5, and 2.86; P = 0.02, 0.05, and 0.02, respectively], and MFI ≧2 was the only predictor for all-cause death. For ejection fraction <40%, age, BNP ≧800 pg/mL, increase in estimated glomerular filtration rate during hospitalization, and lymphocytopenia plus anaemia predicted HF readmission (ORs, 1.77, 2.72, 0.73, and 2.89; P = 0.001, 0.05, 0.04, and 0.03, respectively). In contrast, diabetes mellitus was the only specific predictor found in patients over 80 years old. CONCLUSION: These data identified multi-frailty and PH or mild pancytopenia as synergistic predictors of HF readmission in HFpEF patients.

IL-33 and ST2 comprise a critical biomechanically induced and cardioprotective signaling system.

ST2 is an IL-1 receptor family member with transmembrane (ST2L) and soluble (sST2) isoforms. sST2 is a mechanically induced cardiomyocyte protein, and serum sST2 levels predict outcome in patients with acute myocardial infarction or chronic heart failure. Recently, IL-33 was identified as a functional ligand of ST2L, allowing exploration of the role of ST2 in myocardium. We found that IL-33 was a biomechanically induced protein predominantly synthesized by cardiac fibroblasts. IL-33 markedly antagonized angiotensin II- and phenylephrine-induced cardiomyocyte hypertrophy. Although IL-33 activated NF-kappaB, it inhibited angiotensin II- and phenylephrine-induced phosphorylation of inhibitor of NF-kappa B alpha (I kappa B alpha) and NF-kappaB nuclear binding activity. sST2 blocked antihypertrophic effects of IL-33, indicating that sST2 functions in myocardium as a soluble decoy receptor. Following pressure overload by transverse aortic constriction (TAC), ST2(-/-) mice had more left ventricular hypertrophy, more chamber dilation, reduced fractional shortening, more fibrosis, and impaired survival compared with WT littermates. Furthermore, recombinant IL-33 treatment reduced hypertrophy and fibrosis and improved survival after TAC in WT mice, but not in ST2(-/-) littermates. Thus, IL-33/ST2 signaling is a mechanically activated, cardioprotective fibroblast-cardiomyocyte paracrine system, which we believe to be novel. IL-33 may have therapeutic potential for beneficially regulating the myocardial response to overload.

Molecular mechanisms underlying the onset of degenerative aortic valve disease.

Morbidity from degenerative aortic valve disease is increasing worldwide, concomitant with the ageing of the general population and the habitual consumption of diets high in calories and cholesterol. Immunohistologic studies have suggested that the molecular mechanism occurring in the degenerate aortic valve resembles that of atherosclerosis, prompting the testing of HMG CoA reductase inhibitors (statins) for the prevention of progression of native and bioprosthetic aortic valve degeneration. However, the effects of these therapies remain controversial. Although the molecular mechanisms underlying the onset of aortic valve degeneration are largely unknown, research in this area is advancing rapidly. The signaling components involved in embryonic valvulogenesis, such as Wnt, TGF-beta(1), BMP, and Notch, are also involved in the onset of aortic valve degeneration. Furthermore, investigations into extracellular matrix remodeling, angiogenesis, and osteogenesis in the aortic valve have been reported. Having noted avascularity of normal cardiac valves, we recently identified chondromodulin-I (chm-I) as a crucial anti-angiogenic factor. The expression of chm-I is restricted to cardiac valves from late embryogenesis to adulthood in the mouse, rat, and human. In human degenerate atherosclerotic valves, the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases and angiogenesis is observed in the area of chm-I downregulation. Gene targeting of chm-I resulted in VEGF expression, angiogenesis, and calcification in the aortic valves of aged mice, and aortic stenosis is detected by echocardiography, indicating that chm-I is a crucial factor for maintaining normal cardiac valvular function by preventing angiogenesis. The present review focuses on the animal models of aortic valve degeneration and recent studies on the molecular mechanisms underlying the onset of degenerative aortic valve disease.

Local tenomodulin absence, angiogenesis, and matrix metalloproteinase activation are associated with the rupture of the chordae tendineae cordis.

BACKGROUND: Rupture of the chordae tendineae cordis (CTC) is a well-known cause of mitral regurgitation. Despite its importance, the mechanisms by which the CTC is protected and the cause of its rupture remain unknown. CTC is an avascular tissue. We investigated the molecular mechanisms underlying the avascularity of CTC and the correlation between avascularity and CTC rupture. METHODS AND RESULTS: We found that tenomodulin, which is a recently isolated antiangiogenic factor, was expressed abundantly in the elastin-rich subendothelial outer layer of normal rodent, porcine, canine, and human CTC. Conditioned medium from cultured CTC interstitial cells strongly inhibited tube formation and mobilization of endothelial cells; these effects were partially inhibited by small-interfering RNA against tenomodulin. The immunohistochemical analysis was performed on 12 normal and 16 ruptured CTC obtained from the autopsy or surgical specimen. Interestingly, tenomodulin was locally absent in the ruptured areas of CTC, where abnormal vessel formation, strong expression of vascular endothelial growth factor-A and matrix metalloproteinases, and infiltration of inflammatory cells were observed, but not in the normal or nonruptured area. In anesthetized open-chest dogs, the tenomodulin layer of tricuspid CTC was surgically filed, and immunohistological analysis was performed after several months. This intervention gradually caused angiogenesis and expression of vascular endothelial growth factor-A and matrix metalloproteinases in the core collagen layer in a time-dependent manner. CONCLUSIONS: These findings provide evidence that tenomodulin is expressed universally in normal CTC in a concentric pattern and that local absence of tenomodulin, angiogenesis, and matrix metalloproteinase activation are associated with CTC rupture.

Common marmoset embryonic stem cell can differentiate into cardiomyocytes.

Common marmoset monkeys have recently attracted much attention as a primate research model, and are preferred to rhesus and cynomolgus monkeys due to their small bodies, easy handling and efficient breeding. We recently reported the establishment of common marmoset embryonic stem cell (CMESC) lines that could differentiate into three germ layers. Here, we report that our CMESC can also differentiate into cardiomyocytes and investigated their characteristics. After induction, FOG-2 was expressed, followed by GATA4 and Tbx20, then Nkx2.5 and Tbx5. Spontaneous beating could be detected at days 12-15. Immunofluorescent staining and ultrastructural analyses revealed that they possessed characteristics typical of functional cardiomyocytes. They showed sinus node-like action potentials, and the beating rate was augmented by isoproterenol stimulation. The BrdU incorporation assay revealed that CMESC-derived cardiomyocytes retained a high proliferative potential for up to 24 weeks. We believe that CMESC-derived cardiomyocytes will advance preclinical studies in cardiovascular regenerative medicine.

MicroRNA 33 Regulates the Population of Peripheral Inflammatory Ly6Chigh Monocytes through Dual Pathways.

MicroRNA 33 (miR-33) targets ATP-binding cassette transporter A1 (ABCA1), and its deficiency increases serum high-density lipoprotein (HDL)-cholesterol (HDL-C) and ameliorates atherosclerosis. Although we previously reported that miR-33 deficiency increased peripheral Ly6Chigh monocytes on an ApoE-deficient background, the effect of miR-33 on the monocyte population has not been fully elucidated, especially in a wild-type (WT) background. We found that Ly6Chigh monocytes in miR-33-/- mice were decreased in peripheral blood and increased in bone marrow (BM). Expansion of myeloid progenitors and decreased apoptosis in Lin- Sca1+ c-Kit+ (LSK) cells were observed in miR-33-/- mice. A BM transplantation study and competitive repopulation assay revealed that hematopoietic miR-33 deficiency caused myeloid expansion and increased peripheral Ly6Chigh monocytes and that nonhematopoietic miR-33 deficiency caused reduced peripheral Ly6Chigh monocytes. Expression of high-mobility group AT-hook 2 (HMGA2) targeted by miR-33 increased in miR-33-deficient LSK cells, and its knockdown abolished the reduction of apoptosis. Transduction of human apolipoprotein A1 and ABCA1 in WT mouse liver increased HDL-C and reduced peripheral Ly6Chigh monocytes. These data indicate that miR-33 deficiency affects distribution of inflammatory monocytes through dual pathways. One pathway involves the enhancement of Hmga2 expression in hematopoietic stem cells to increase Ly6Chigh monocytes, and the other involves the elevation of HDL-C to decrease peripheral Ly6Chigh monocytes.

Hepatokine α1-Microglobulin Signaling Exacerbates Inflammation and Disturbs Fibrotic Repair in Mouse Myocardial Infarction.

Acute cardiac rupture and adverse left ventricular (LV) remodeling causing heart failure are serious complications of acute myocardial infarction (MI). While cardio-hepatic interactions have been recognized, their role in MI remains unknown. We treated cultured cardiomyocytes with conditioned media from various cell types and analyzed the media by mass spectrometry to identify α1-microglobulin (AM) as an Akt-activating hepatokine. In mouse MI model, AM protein transiently distributed in the infarct and border zones during the acute phase, reflecting infiltration of AM-bound macrophages. AM stimulation activated Akt, NFκB, and ERK signaling and enhanced inflammation as well as macrophage migration and polarization, while inhibited fibrogenesis-related mRNA expression in cultured macrophages and cardiac fibroblasts. Intramyocardial AM administration exacerbated macrophage infiltration, inflammation, and matrix metalloproteinase 9 mRNA expression in the infarct and border zones, whereas disturbed fibrotic repair, then provoked acute cardiac rupture in MI. Shotgun proteomics and lipid pull-down analysis found that AM partly binds to phosphatidic acid (PA) for its signaling and function. Furthermore, systemic delivery of a selective inhibitor of diacylglycerol kinase α-mediated PA synthesis notably reduced macrophage infiltration, inflammation, matrix metalloproteinase activity, and adverse LV remodeling in MI. Therefore, targeting AM signaling could be a novel pharmacological option to mitigate adverse LV remodeling in MI.

Application of mesenchymal stem cell-derived cardiomyocytes as bio-pacemakers: current status and problems to be solved.

Bone marrow mesenchymal stem cells (CMG cells) are multipotent and can be induced by 5-azacytidine to differentiate into cardiomyocytes. We characterized the electrophysiological properties of these cardiomyocytes and investigated their potential for use as transplantable bio-pacemakers. After differentiation, action potentials in spontaneously beating cardiomyocytes were initially sinus node-like, but subsequently became ventricular cardiomyocyte-like. RT-PCR established that ion channels mediating I(K1) and I(Kr) were expressed before differentiation. After differentiation, ion channels underlying ICa,L and If were expressed first, followed by ion channels mediating I(to) and I(K,ATP). Differentiated CMG cells expressed beta-adrenergic receptors and increased their beat rate in response to isoproterenol. CMG cardiomyocytes were purified using GFP fluorescence and transplanted into the free walls of the left ventricles of mice. The transplanted cardiomyocytes survived and connected to surrounding recipient cardiomyocytes via intercalated discs. Although further innovation is required, the present findings provide evidence of the potential for bone marrow-derived cardiomyocytes to be used as bio-pacemakers.

[Role of anti-angiogenic factor chondromodulin-I for maintaining cardiac valvular function].

Cardiac valves are recognized as avascular tissue as well as cartilage and eye. We recently identified chondromodulin-I as crucial anti-angiogenic factor for maintaining cardiac valvular function. chondromodulin-I was first detected at developmental stage E9.5 in outflow tract, valvular primordium, and left ventricle, but was restricted to cardiac valves from late embryogenesis to adult. In ApoE(-/-) mice and human valvular heart diseases such as atherosclerosis, rheumatic heart diseases, and infective endocarditis, vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP) expression and neovascularization were observed in the area of down-regulation of chondromodulin-I. Conditioned medium from cultured-valvular interstitial cells strongly inhibited tube formation and migration of endothelial cells, and these effects were partially blocked by chondromodulin-I siRNA in vitro. Gene targeting of chondromodulin-I caused VEGF expression, neovascularization, lipid deposition, and calcification in cardiac valves of aged mice. Echocardiography showed aortic valve thickening and turbulent flow suggesting early stage of aortic stenosis. These findings provide evidence that chondromodulin-I is a crucial factor for maintaining normal cardiac valvular function by preventing angiogenesis that may lead to valvular heart diseases.

Prevention of neointimal formation using miRNA-126-containing nanoparticle-conjugated stents in a rabbit model.

BACKGROUND: Despite recent progress with drug-eluting stents, restenosis and thrombosis after endovascular intervention are still major limitations in the treatment of cardiovascular diseases. These problems are possibly caused by inappropriate inhibition of neointimal formation and retardation of re-endothelialization on the surface of the stents. miR-126 has been shown to have the potential to enhance vascular endothelial cell proliferation. METHODS AND RESULTS: We designed and constructed a 27-nt double strand RNA (dsRNA) conjugated to cholesterol, which has high membrane permeability, and formed mature miR-126 after transfection. For site-specific induction of miR-126, we utilized poly (DL-lactide-co-glycolide) nanoparticles (NPs). miR-126-dsRNA-containing NPs (miR-126 NPs) significantly reduced the protein expression of a previously identified miR-126 target, SPRED1, in human umbilical vascular endothelial cells (HUVECs), and miR-126 NPs enhanced the proliferation and migration of HUVECs. On the other hand, miR-126 NPs reduced the proliferation and migration of vascular smooth muscle cells, via the suppression of IRS-1. Finally, we developed a stent system that eluted miR-126. This delivery system exhibited significant inhibition of neointimal formation in a rabbit model of restenosis. CONCLUSIONS: miR-126 NP-conjugated stents significantly inhibited the development of neointimal hyperplasia in rabbits. The present study may indicate the possibility of a novel therapeutic option to prevent restenosis after angioplasty.

Dynamic changes of serum microRNA-122-5p through therapeutic courses indicates amelioration of acute liver injury accompanied by acute cardiac decompensation.

AIMS: Recent studies have shown that serum microRNA (miR) abundance is informative for the diagnosis or prognosis of heart failure. However, the dynamics and kinetics of miRs in acute heart failure are largely unknown. Serial measurement and analysis of serum miRs changes in individuals along their therapeutic course could reduce inter-individual variation and should detect potentially important serum miRs related to disease mechanisms. Based on this concept, we profiled serum miR signatures of blood samples that were obtained sequentially on the day of admission and on hospital Day 7. METHODS AND RESULTS: This prospective, observational study included 42 consecutive acute heart failure patients (74 ± 1 years old, 24 male). From admission to Day 7, most of the patients showed clinical improvement. In such a cohort, we detected several fluctuations of serum miRs by two distinct screening methods (quantitative PCR and high-throughput sequencing). One of these fluctuating serum miRs, miR-122-5p, decreased significantly from Day 1 to Day 7 [median arbitrary unit (1st:3rd quantile value); 4.62 [2.39:12.3] to 3.07 [1.67:5.39], P = 0.007]. This fluctuation was significantly correlated with changes in serum liver function markers (estimated coefficient and 95% confidence interval; vs change in aspartate aminotransferase 1.69, 0.890-2.484, P < 0.001 and r = 0.560, vs change in alanine aminotransferase 1.09, 0.406-1.771, P = 0.007 and r = 0.428). CONCLUSIONS: The serum miR signature of patients with acute heart failure might indicate the severity of the disease or patients' response to therapeutic intervention. Notably, serum miR-122-5p levels reflect liver damage in this condition.

Injectable self-assembling peptide nanofibers create intramyocardial microenvironments for endothelial cells.

BACKGROUND: Promoting survival of transplanted cells or endogenous precursors is an important goal. We hypothesized that a novel approach to promote vascularization would be to create injectable microenvironments within the myocardium that recruit endothelial cells and promote their survival and organization. METHODS AND RESULTS: In this study we demonstrate that self-assembling peptides can be injected and that the resulting nanofiber microenvironments are readily detectable within the myocardium. Furthermore, the self-assembling peptide nanofiber microenvironments recruit progenitor cells that express endothelial markers, as determined by staining with isolectin and for the endothelial-specific protein platelet-endothelial cell adhesion molecule-1. Vascular smooth muscle cells are recruited to the microenvironment and appear to form functional vascular structures. After the endothelial cell population, cells that express alpha-sarcomeric actin and the transcription factor Nkx2.5 infiltrate the peptide microenvironment. When exogenous donor green fluorescent protein-positive neonatal cardiomyocytes were injected with the self-assembling peptides, transplanted cardiomyocytes in the peptide microenvironment survived and also augmented endogenous cell recruitment. CONCLUSIONS: These experiments demonstrate that self-assembling peptides can create nanofiber microenvironments in the myocardium and that these microenvironments promote vascular cell recruitment. Because these peptide nanofibers may be modified in a variety of ways, this approach may enable injectable tissue regeneration strategies.