Left atrial strain time integral evaluated by two-dimensional speckle tracking predicts left atrial appendage dysfunction in patients with acute ischemic stroke.

Cardioembolic stroke is a serious disease with poor prognosis, whose main embolic source is the left atrial appendage (LAA). Left atrial (LA) strain evaluated by the two-dimensional (2D) speckle tracking technique has been proposed. However, the commonly used peak LA strain reflects only LA reservoir function. The LA strain also includes indicators of the other LA functions, such as booster pump function, which reflects active contraction of the LA. This study aimed to investigate whether a newly developed parameter, the left atrial strain time integral (LASTI), can evaluate LAA dysfunction more accurately in patients with acute stroke. We measured LA strain using a 2D speckle tracking method in 168 patients with acute stroke and 20 age-matched control subjects. LASTI was calculated as the area under the LA strain curve in one cardiac cycle. LAA dysfunction was defined as LAA thrombus and/or severe spontaneous echo contrast by transesophageal echocardiography. LASTI was significantly lower in patients with LAA dysfunction than those without. LASTI was a better correlation with LAA blood flow velocity measured by transesophageal echocardiography than peak LA strain. Multivariate logistic regression analysis showed that LASTI was an independent predictor of LAA dysfunction after adjustment for conventional risk factors. LASTI can be a feasible parameter for predicting LAA dysfunction in patients with acute stroke.

Improved cerebral blood flow and hippocampal blood flow in stroke-free patients after catheter ablation of atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is a risk factor for reduced cerebral blood flow (CBF) and cognitive dysfunction, even in stroke-free patients. We aimed to test the hypothesis that CBF and hippocampal blood flow (HBF), measured with arterial spin labeling magnetic resonance imaging (MRI), improve after catheter ablation of AF to achieve sinus rhythm (SR). METHODS: A total of 84 stroke-free patients (63.1 ± 9.1 years; paroxysmal AF, n = 50; non-paroxysmal AF, n = 34) undergoing AF catheter ablation were included. MRI studies were done before, 3 months, and 12 months after the procedure with CBF and HBF measurements. RESULTS: Baseline CBF and HBF values in 50 paroxysmal AF patients were used as controls. Baseline CBF was higher in patients with paroxysmal AF than with non-paroxysmal AF (100 ± 32% vs. 86 ± 28%, p = .04). Patients with non-paroxysmal AF had increased CBF 3 months after AF ablation (86 ± 28% to 99 ± 34%, p = .03). Differences in CBF and HBF were greater in the group with AF restored to SR (p < .01). Both CBF and HBF levels at 12 months were unchanged from the 3 months level. Successful rhythm control by catheter ablation was an independent predictor of an increase in CBF > 17.5%. The Mini-Mental State Examination score improved after ablation (p = .02). CONCLUSION: SR restoration with catheter ablation was associated with improved CBF and HBF at 3 months, maintenance of blood flow, and improved cognitive function at 12 months.

Association between thrombolysis in myocardial infarction grade and clinical outcome after emergent percutaneous coronary intervention in patients with acute myocardial infarction who have suffered out-of-hospital cardiac arrest: the Yamagata AMI registry.

Despite improvements in the survival rate of acute myocardial infarction (AMI), out-of-hospital cardiac arrest (OHCA) due to AMI is still a devastating condition. Thrombolysis in myocardial infarction (TIMI) grade is used to classify coronary reperfusion after percutaneous coronary intervention (PCI), but it remains unclear whether TIMI grade after emergent PCI is associated with short-term mortality in patients with AMI who have suffered OHCA. We analyzed data collected from 2012 to 2017 and recorded in the Yamagata AMI registry, which is a multicenter surveillance conducted in all institutions in Yamagata prefecture. Among 3332 patients with AMI, 254 had suffered OHCA. There were 564 deaths during the 30 days after the onset of AMI. The survival rate was lower in patients who had suffered OHCA than in those who had not (40% vs. 87%; P < 0.0001). Patients with AMI who had suffered OHCA were divided into three groups based on TIMI grade (TIMI III group, n = 70; TIMI ≤ II group, n = 21; and no coronary angiography [non-CAG] group, n = 163). The survival rates in the TIMI III, TIMI ≤ II, and non-CAG groups were 87%, 38%, and 5%, respectively. Kaplan-Meier analysis demonstrated that the survival rate was highest in the TIMI III group. Multivariate Cox proportional hazard regression analysis demonstrated that TIMI III was closely associated with survival after adjustment for confounding factors. Achieving TIMI grade III during emergent PCI is crucial to improve survival in patients with AMI who have suffered OHCA.

Perfusion Balloon Is Useful for Preventing Obstruction of Left Main Coronary Artery During Transcatheter Aortic Valve Implantation.

The incidence of acute coronary obstruction during transcatheter aortic valve implantation (TAVI) is low (< 1.0%); however, it is associated with high mortality. An 83-year-old female with a history of chest pain and syncope was diagnosed with severe aortic stenosis. Computed tomography showed severely calcified aortic leaflets with a low left coronary ostial height of 7.8 mm, which indicates a high risk of coronary obstruction. TAVI was performed using the right femoral artery approach under general anesthesia. To prevent coronary obstruction and minimize coronary flow obstruction, coronary protection of the left main tract (LMT) via the left radial artery was established with a perfusion balloon. We crossed a 23 mm Sapien 3 transcatheter heart valve and settled it at an appropriate position on the aortic valve. After inflation of the perfusion balloon at the LMT, we started rapid ventricular pacing, and deployed the Sapien 3 using the KBI technique. Hemodynamics were stable and aortography showed excellent coronary flow with no stenosis of the LMT ostium. This strategy may serve as a useful method to prevent coronary obstruction and minimize coronary ischemia.

Left Atrial Filling Time Index (LAFTI) Evaluated by 2D Speckle Tracking Echocardiography Predicts Poor Cardiac Prognosis in Patients with Heart Failure.

Left atrial (LA) dysfunction is known to be a more sensitive prognostic marker than left ventricular (LV) dysfunction in patients with heart failure (HF). Persistent LA overload increases LA stiffness which impairs LA relaxation. The aim of this study was to investigate whether LA filling time is associated with clinical outcomes in patients with HF. Two-dimensional speckle tracking echocardiography (2DSTE) was performed at discharge, to measure LA and LV strain in 179 HF patients admitted to our hospital. The LA filling time index (LAFTI) was defined as the time from onset of the R wave to the peak LA systolic strain divided by the R-R interval. All patients were prospectively followed with cardiac events including cardiac death and rehospitalization for HF. There were 64 cardiac events during a median follow-up period of 451 days. There were no significant differences in heart rate, severity of HF at discharge, etiology of HF, severity of mitral regurgitation, or LV global longitudinal strain between the cardiac event group and no cardiac event group. Patients with cardiac events had significantly higher levels of brain natriuretic peptide (BNP), ratio of the E wave to e' (E/e'), left atrial volume index (LAVI), and lower LAFTI than those without. Kaplan-Meier analysis showed that patients with lower LAFTI were associated with higher cardiac event rates. Multivariate Cox hazard analysis showed that LAFTI was independently associated with the cardiac events after adjustment for confounding factors. In conclusion, LAFTI is a feasible predictor for cardiac events in patients with HF.

Prolonged total atrial conduction time evaluated with tissue Doppler imaging predicts poor cardiac prognosis in patients with heart failure.

Prolonged total atrial conduction time is caused by atrial remodeling. Left atrial remodeling is associated with poor outcome in patients with heart failure (HF). This study aimed to investigate whether prolonged total atrial conduction time predicts poor prognosis in patients with HF. We performed transthoracic echocardiography in 100 patients (65 men; mean age 68 ± 13 years) who were hospitalized for HF. Total atrial conduction time was defined as the duration from P wave onset on electrocardiography to peak A' wave on tissue Doppler imaging (TDI) echocardiography (PA-TDI duration). There were 37 cardiac events (37%) during a median follow-up period of 414 days. The PATDI duration was significantly longer in patients with cardiac events than in those without (150 ± 18 ms vs 133 ± 19 ms; P < 0.05). There were no significant differences in left ventricular end-diastolic dimensions and ejection fractions between patients with and without cardiac events. Patients with HF were divided into 3 groups according to tertiles of the PA-TDI duration. Kaplan-Meier analysis showed that the highest tertile of PA-TDI duration was associated with the greatest risk among patients with HF. Multivariate Cox proportional hazard analysis showed that the PA-TDI duration was an independent predictor of cardiac events, leading to the conclusion that prolonged PA-TDI duration was a feasible predictor of cardiac prognosis in patients with HF.

Direct comparison of prognostic ability of cardiac biomarkers for cardiogenic stroke and clinical outcome in patients with stroke.

Despite many recent advances in medicine, cardiogenic stroke is still a health problem with a high mortality rate. Cardiac biomarkers have been reported to be useful indicators for cardiogenic stroke and subsequent cerebrovascular events. However, there are no data directly comparing the cardiac biomarkers in stroke patients. We measured atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-proBNP), and high-sensitivity troponin T (hsTnT) levels and performed transthoracic and transesophageal echocardiography in 282 stroke patients. There were 108 cases of cardiogenic stroke and 47 cases of major adverse cardiovascular and cerebrovascular events (MACCE) during the follow-up period. Association with left atrial function and left atrial appendage function appeared somewhat stronger for BNP and NT-proBNP than ANP and hsTnT. Multivariate logistic analysis demonstrated that cardiac biomarkers excluding ANP were significantly associated with cardiogenic stroke in stroke patients, multivariate Cox's proportional hazards regression analysis demonstrated that all biomarkers were significantly associated with MACCE after adjustment for confounding risk factors. Receiver operating characteristic curve analysis showed that the C indices of BNP and NT-proBNP for cardiogenic stroke and MACCE were almost equal, but significantly greater than those of ANP and hsTnT. Both BNP and NT-proBNP levels are useful predictors of cardiogenic stroke and subsequent MACCE superior to ANP and hsTnT in stroke patients.

Left atrial remodeling index is a feasible predictor of poor prognosis in patients with acute ischemic stroke.

Left atrial (LA) functional remodeling as well as LA structural remodeling are associated with incident LA appendage (LAA) thrombus formation. This study aimed to elucidate whether combined assessment of LA functional and structural remodeling can predict LAA dysfunction and recurrent cerebrovascular events in patients with acute ischemic stroke. We performed transthoracic and transesophageal echocardiography in 196 patients within 7 days after acute ischemic stroke. Peak systolic LA strain was evaluated using 2D speckle tracking imaging. We defined the ratio of LA peak systolic strain to LA volume index (LAVI) as the LA remodeling index (LARI). All patients were prospectively followed for recurrent cerebrovascular events. We divided patients into four groups according based on the LARI quartile. LAA dysfunction increased with decreasing LARI. In total, 52 recurrent cerebrovascular events were noted during the median follow-up period of 700 days. Patients with recurrent cerebrovascular events had lower LARI than those without recurrent events (0.50 ± 0.45 vs. 1.10 ± 0.95, P < 0.001). Kaplan-Meier analysis showed that patients with lower LARI were more susceptible to recurrent cerebrovascular events than those with higher LARI. Multivariate Cox proportional hazard regression analysis showed that LARI was an independent predictor of recurrent cerebrovascular events after adjustment for confounding factors. Net reclassification index improved with the addition of LARI to basic predictors. LARI is a novel feasible parameter for LAA dysfunction and can predict recurrent cerebrovascular events in patients with acute ischemic stroke.

Increased plasma xanthine oxidoreductase activity deteriorates coronary artery spasm.

Increased reactive oxygen species (ROS) contributes to the development of endothelial dysfunction, which is involved in coronary artery spasm (CAS). Xanthine oxidoreductase (XOR) plays a pivotal role in producing both uric acid and ROS. However, the association between plasma XOR activity and CAS has not been elucidated. The aim of this study was to investigate whether plasma XOR activity is associated with CAS. We measured XOR activity in 104 patients suspected for CAS, who presented without significant coronary artery stenosis and underwent intracoronary acetylcholine provocation tests. CAS was provoked in 44 patients and they had significantly higher XOR activity as compared with those without CAS. The patients were divided into three groups based on the XOR activity. The prevalence rate of CAS was increased with increasing XOR activity. A multivariate logistic regression analysis showed that the 3rd tertile group exhibited a higher incidence of CAS as compared with the 1st tertile group [odds ratio (OR) 6.9, P = 0.001) and the 2nd tertile group (OR 3.2, P = 0.033) after adjustment for conventional CAS risk factors, respectively. The C index was significantly improved by the addition of XOR activity to the baseline model based on CAS risk factors. Furthermore, the 3rd tertile group had the highest incidence of severe spasm defined as total obstruction, flow-limiting stenosis, diffuse spasm, multivessel spasm, and/or lethal arrhythmia. This is a first report to elucidate the association of plasma XOR activity with CAS. Increased plasma XOR activity is significantly associated with CAS.

Rapid decline in renal function after acute myocardial infarction.

AIM: To investigate the long term effects of cardiac events on renal function, a prospective study of patients with acute myocardial infarction was conducted. METHODS: A total of 137 patients with acute myocardial infarction were followed for 1 year. The change of estimated glomerular filtration rate (eGFR) in cardiac patients was compared with that in background-matched controls, and the factors associated with eGFR changes were analyzed. RESULTS: The eGFR decrease was much larger after myocardial infarction, from 73.7 ± 1.9 ml/min/1.73 m2 (mean ± SEM) at baseline to 64.7 ± 1.7 at 1 year, (p < 0.001), compared with that of controls (from 72.8 ± 1.2 to 72.1 ± 1.3, p = 0.305). Multiple regression analysis showed that eGFR change was associated negatively with age, baseline eGFR, proteinuria, and positively with the administration of angiotensin converting enzyme inhibitors or angiotensin II receptor blockers, but not the severity of cardiac damage and comorbidities. Longitudinal analysis 1 year before and 2 years after myocardial infarction showed that eGFR decrease was larger during baseline and 6 months after the event (-7.0 ± 1.0). CONCLUSIONS: Renal decline was rapid after myocardial infarction and was affected by clinical characteristics of patients. Careful follow-up of renal function is recommended to prevent the progression of renal and cardiac disease.

Anticoagulation therapy for endocardial/epicardial ablation of infarct-related ventricular tachycardia in a patient with antithrombin deficiency.

In patients with a history of antithrombin deficiency, a direct thrombin inhibitor may be considered as an alternative to intraprocedural anticoagulation. A 55-year-old woman with antithrombin deficiency and prior myocardial infarction suffered from electrical storm and appropriate defibrillator shocks. Substrate mapping guided left ventricular endocardial and epicardial ablations were successfully performed. The direct thrombin inhibitor, argatroban, was safely used as intraprocedural anticoagulation therapy with no complications. Learning objective: Optimal anticoagulation during endocardial and epicardial catheter ablation is essential to prevent thromboembolic and bleeding complications. Although patients with infarct-related electrical storm and antithrombin deficiency require unusual attention to anticoagulation, argatroban, a direct thrombin inhibitor, was safely used as intraprocedural anticoagulation therapy during catheter ablations, with no complications.

Prognostic Impact of Renal Dysfunction at 1-Year Follow-Up on Clinical Outcomes After Percutaneous Coronary Intervention.

AIMS: Renal dysfunction is an independent predictor of adverse outcomes in patients with coronary artery disease (CAD). However, the prognostic impact of mid-term changes in renal dysfunction status remains unclear. This study aimed to investigate the impact of mid-term changes in renal dysfunction status on long-term clinical outcomes in CAD patients who underwent percutaneous coronary intervention (PCI). METHODS: We enrolled 382 consecutive patients with CAD who underwent PCI. Renal dysfunction was defined as a reduced estimated glomerular filtration rate (eGFR) of ＜60 mL/min/1.73m2. Renal dysfunction status was evaluated at baseline and 1-year follow-up after PCI. We divided the study population into three groups: persistent renal dysfunction, new-onset renal dysfunction, and no or improved renal dysfunction at 1-year follow-up as compared with on baseline. The endpoints of this study were composite events, including all-cause death, acute coronary syndrome, target vessel revascularization, and stroke. RESULTS: At baseline, renal dysfunction was observed in 77 patients (20%). At the 1-year follow-up, new-onset renal dysfunction was observed in 46 patients (12%), and 59 patients (15%) had persistent renal dysfunction. Kaplan-Meier analysis revealed a significantly higher event rate in patients with persistent renal dysfunction and new-onset renal dysfunction (log-rank test, P=0.0003). In the multivariate Cox proportional hazards analysis, persistent renal dysfunction and new-onset renal dysfunction were independently associated with composite events after adjusting for confounding factors (adjusted hazard ratios 4.08 and 2.64, 95% confidence intervals 1.72-9.57 and 1.03-6.31, P=0.0016, P=0.0045, respectively). CONCLUSION: Persistent and new-onset renal dysfunction at 1-year follow-up were associated with unfavorable outcomes in patients with CAD who underwent PCI.

A case of a transcatheter valve-in-valve implantation using balloon expandable valve for failed SOLO SMART stentless bioprosthetic valve.

A 74-year-old man who had undergone surgical aortic valve replacement with the SOLO SMART stentless bioprosthetic valve 25 mm (LivaNova PLC, London, UK) and mitral valve replacement with MOSAIC 29 mm (Medtronic, Minneapolis, USA) 4 years previously was diagnosed with congestive heart failure, and transferred to our hospital. Echocardiography revealed severe aortic regurgitation caused by degraded bioprosthetic valve. He required continuous dobutamine administration to maintain hemodynamics. As a result of heart team discussion, we decided to perform transcatheter valve-in-valve implantation (ViV-TAVI) using balloon expandable valve (Sapien 3, Edwards Lifesciences, Irvine, USA). Since SOLO SMART stentless valve was placed to Valsalva sinus at the supra-annular level with continuous sutures, we planned to anchor TAVI valve 4 mm to the left ventricular side from the bottom of the failed stentless valve. Two pigtail catheters were placed at the bottom of the failed stentless valve leaflet to mark the nadir of stentless valve. After ViV-TAVI, the patient no longer required catecholamine administration and was discharged home one month later. This is the first case of ViV-TAVI using balloon expandable valve for failed SOLO SMART stentless bioprosthetic valve in a Japanese patient. Learning objective: Transcatheter valve-in-valve implantation (ViV-TAVI) for stentless valves is known to be technically challenging due to poor fluoroscopic visibility. Because the SOLO SMART stentless bioprosthetic valve is sutured to the wall of the sinus of Valsalva above the annulus, the landing point of transcatheter heart valve is at a native annulus which is lower than the bottom of the SOLO SMART leaflet. We describe the first Japanese case of ViV-TAVI with balloon expandable valve for the SOLO SMART stentless bioprosthetic valve.

Impact of activities of daily living on percutaneous coronary intervention and acute and long-term mortality in patients with acute myocardial infarction: Yamagata AMI registry.

BACKGROUND: A decrease in the activities of daily living (ADL) is an independent risk factor for cardiovascular disease. Although percutaneous coronary intervention (PCI) is known to prevent early mortality in patients with acute myocardial infarction (AMI), the relationship between ADL prior to myocardial infarction (MI), PCI implementation, and mortality in patients with AMI remains unknown. We investigated the impact of prehospital ADL on PCI implementation and on short- and long-term mortality in patients with AMI. METHODS: We investigated the prehospital ADL in 1479 patients with AMI using data from the Yamagata AMI registry (period: 2015-2017). The patients were divided into three groups (preserved ADL, mildly impaired ADL, and severely impaired ADL) and their clinical characteristics were compared. Multivariate regression analysis was performed to elucidate the association of ADL prior to MI with the PCI implementation and mortality in patients with AMI. RESULTS: Patients with impaired ADL were older, more likely to be female, less likely to have undergone PCI, and presented with higher acute mortality compared to those with preserved ADL. The proportion of patients with impaired ADL increased with age. Multivariate regression analysis showed that the lack of PCI implementation and prehospital ADL impairment were independent risk factors for acute death in patients with AMI after adjusting for confounding factors. Furthermore, univariate and multivariate analyses revealed that impaired ADL was associated with the PCI implementation. Cox proportional hazards analysis revealed that prehospital ADL impairment was an independent risk factor for long-term mortality in patients with AMI. CONCLUSIONS: Decreased levels of prehospital ADL were associated with lower PCI implementation and higher mortality in patients-especially older patients-with AMI.

Effects of Nitric Oxide Synthase 3 Gene Polymorphisms on Cardiovascular Events in a General Japanese Population　- The Yamagata (Takahata) Study.

Background: Single nucleotide polymorphisms (SNPs) in nitric oxide synthase 3 (NOS3) are associated with cardiovascular risk factors. However, it is not clear whether the NOS3 SNP is a genetic risk factor for cardiovascular diseases. Methods and Results: This prospective cohort study included 2,726 subjects aged ≥40 years who participated in a community-based health checkup. We genotyped 639 SNPs, including 2 NOS3 SNPs (rs1799983 and rs1808593). All subjects were monitored prospectively over a median follow-up period of 16.0 years, with the endpoint being cardiovascular events, including cardiovascular death and/or non-fatal myocardial infarction. Kaplan-Meier analysis demonstrated that both rs1799983 GT/TT and rs1808593 GG carriers had a higher risk of the endpoint than non-carriers. Univariate and multivariate Cox proportional hazard regression analyses revealed that both rs1799983 GT/TT and rs1808593 GG were independently associated with cardiovascular events after adjusting for confounding risk factors. The net reclassification index and integrated discrimination index were significantly improved by the addition of NOS3 SNPs as cardiovascular risk factors. Conclusions: NOS3 gene polymorphisms could be genetic risk factors for cardiovascular events in the general Japanese population, and could be used to facilitate the early identification of individuals at high risk of cardiovascular events.

Ivabradine as an Adjuvant Agent for Severe Heart Failure Occurring in the Early Phase after Allogeneic Hematopoietic Cell Transplantation.

Cardiotoxicity is a critical complication of allogeneic hematopoietic cell transplantation (allo-HCT). In particular, management of severe cardiotoxicity occurring in the early phases of allo-HCT is challenging. We encountered a case of severe cardiotoxicity resulting from AHF six days after allo-HCT, which resisted catecholamines and diuretics. The patient was treated with anthracycline-containing regimens and underwent myeloablative conditioning, including high-dose cyclophosphamide. As invasive circulatory assisting devices were contraindicated because of his immunocompromised status and bleeding tendency, we successfully treated the patient with ivabradine-containing medications. Ivabradine may therefore be considered an alternative drug for the treatment of severe cardiotoxicity induced by cytotoxic agents.

Unmet needs for emergency care and prevention of prehospital death in acute myocardial infarction.

INTRODUCTION: Percutaneous coronary intervention (PCI) has successfully reduced the mortality of patients with acute myocardial infarction (AMI). However, patients with out-of-hospital cardiac arrest have high mortality, which is difficult to control by hospital staff. In this study, we investigated the prevalence of prehospital death (PHD) in patients with AMI. Furthermore, we investigated the risk factors associated with 30-day mortality in patients with AMI who survived PHD. METHODS: We investigated the prevalence of PHD using data from the Yamagata AMI registry and from death certification of the entire Yamagata Prefecture in Japan between 2010 and 2015. Furthermore, we investigated the risk factors for 30-day mortality in patients who survived PHD, using data from the Yamagata AMI registry from 1993 to 2015. AMI was identified by the International Classification of Diseases, 10th revision code I21. RESULTS: Out of the 6984 patients with AMI, 3771 patients had PHD. Patients with PHD were older and more likely to be women than those without PHD. More PHD occurred in winter and spring than in summer or autumn. Multivariate regression analysis showed that age, female sex, and winter onset were independently associated with PHD. We also investigated the risk factors associated with 30-day mortality in 9675 patients who survived PHD. The rate of PCI was remarkably lower in patients with acute death than in those without acute death. Multivariate regression analysis showed that age, anterior infarction, estimated glomerular filtration rate, Killip class, and PCI were independently associated with 30-day mortality after adjusting for confounding factors. CONCLUSION: Approximately half of the patients with AMI died before they could reach the destination hospital. Although emergency PCI is the most important factor in reducing 30-day mortality in patients with AMI, attempts to reduce patient delay and system delay are possibly needed to further reduce PHD.

HECT (Homologous to the E6-AP Carboxyl Terminus)-Type Ubiquitin E3 Ligase ITCH Attenuates Cardiac Hypertrophy by Suppressing the Wnt/ß-Catenin Signaling Pathway.

The HECT (homologous to the E6-AP carboxyl terminus)-type ubiquitin E3 ligase ITCH is an enzyme that plays an important role in ubiquitin-proteasomal protein degradation. Disheveled proteins (Dvl1 [disheveled protein 1], Dvl2, and Dvl3) are the main components of the Wnt/ß-catenin signaling pathway, which is involved in cardiac hypertrophy. The aim of this study was to examine the role of ITCH during development of cardiac hypertrophy. Thoracic transverse aortic constriction (TAC) was performed in transgenic mice with cardiac-specific overexpression of ITCH (ITCH-Tg) and wild-type mice. Cardiac hypertrophy after TAC was attenuated in ITCH-Tg mice, and the survival rate was higher for ITCH-Tg mice than for wild-type mice. Protein interaction between ITCH and Dvls was confirmed with immunoprecipitation in vivo and in vitro. Expression of key molecules of the Wnt/ß-catenin signaling pathway (Dvl1, Dvl2, GSK3ß [glycogen synthase kinase 3ß], and ß-catenin) was inhibited in ITCH-Tg mice compared with wild-type mice. Notably, the ubiquitination level of Dvl proteins increased in ITCH-Tg mice. Protein and mRNA expression levels of ITCH increased in response to Wnt3a stimulation in neonatal rat cardiomyocytes. Knockdown of ITCH using small-interfering RNA increased cardiomyocyte size and augmented protein expression levels of Dvl proteins, phospho-GSK3ß, and ß-catenin after Wnt3a stimulation in cardiomyocytes. Conversely, overexpression of ITCH attenuated cardiomyocyte hypertrophy and decreased protein expression levels of Dvl proteins, phospho-GSK3ß and ß-catenin. In conclusion, ITCH targets Dvl proteins for ubiquitin-proteasome degradation in cardiomyocytes and attenuates cardiac hypertrophy by suppressing the Wnt/ß-catenin signaling pathway.

The association between microRNA-21 and hypertension-induced cardiac remodeling.

Hypertension is a major public health problem among the aging population worldwide. It causes cardiac remodeling, including hypertrophy and interstitial fibrosis, which leads to development of hypertensive heart disease (HHD). Although microRNA-21 (miR-21) is associated with fibrogenesis in multiple organs, its contribution to cardiac remodeling in hypertension is poorly understood. Circulating miR-21 level was higher in patients with HHD than that in the control subjects. It also positively correlated with serum myocardial fibrotic markers. MiR-21 expression levels were significantly upregulated in the mice hearts after angiotensin II (Ang II) infusion or transverse aortic constriction (TAC) compared with control mice. Expression level of programmed cell death 4 (PDCD4), a main target of miR-21, was significantly decreased in Ang II infused mice and TAC mice compared with control mice. Expression levels of transcriptional activator protein 1 (AP-1) and transforming growth factor-ß1 (TGF-ß1), which were downstream targets of PDCD4, were increased in Ang II infused mice and TAC mice compared with control mice. In vitro, mirVana-miR-21-specific inhibitor attenuated Ang II-induced PDCD4 downregulation and contributed to subsequent deactivation of AP-1/TGF-ß1 signaling pathway in neonatal rat cardiomyocytes. Thus, suppression of miR-21 prevents hypertrophic stimulation-induced cardiac remodeling by regulating PDCD4, AP-1, and TGF-ß1 signaling pathway.