Teruyoshi Uetani

Insufficiency of Pro-heparin-binding Epidermal Growth Factor-like Growth Factor Shedding Enhances Hypoxic Cell Death in H9c2 Cardiomyoblasts via the Activation of Caspase-3 and c-Jun N-terminal Kinase

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a cardiogenic and cardiohypertrophic growth factor. ProHB-EGF, a product of the Hb-egf gene and the precursor of HB-EGF, is anchored to the plasma membrane. Its ectodomain region is shed by a disintegrin and metalloproteases (ADAMs) when activated by various stimulations. It has been reported that an uncleavable mutant of Hb-egf, uc-Hb-egf, produces uc-proHB-EGF, which is not cleaved by ADAMs and causes dilation of the heart in knock-in mice. This suggests that the shedding of proHB-EGF is essential for the development and survival of cardiomyocytes: however, the molecular mechanism involved has remained unclear. In this study, we investigated the relationship between uc-proHB-EGF expression and cardiomyocyte survival. Human uc-proHB-EGF was adenovirally introduced into the rat cardiomyoblast cell line H9c2, and the cells were cultured under normoxic and hypoxic conditions. Uc-proHB-EGF-expressing H9c2 cells underwent apoptosis under normoxic conditions, which distinctly increased under hypoxic conditions. Furthermore, we observed an increased Caspase-3 activity, reactive oxygen species accumulation, and an increased c-Jun N-terminal kinase (JNK) activity in the uc-proHB-EGF-expressing H9c2 cells. Treatment of the uc-proHB-EGF transfectants with inhibitors of Caspase-3, reactive oxygen species, and JNK, namely, Z-VAD-fmk, N-acetylcysteine, and SP600125, respectively, significantly reduced hypoxic cell death. These data indicate that insufficiency of proHB-EGF shedding under hypoxic stress leads to cardiomyocyte apoptosis via Caspase-3- and JNK-dependent pathways.

Association Between Genetic Variation in the SCN10A Gene and Cardiac Conduction Abnormalities in Patients With Hypertrophic Cardiomyopathy.

Arrhythmias are associated with reduced quality of life and poor prognosis in patients with hypertrophic cardiomyopathy (HCM). Recent genome-wide association studies revealed that a nonsynonymous single nucleotide polymorphism, rs6795970, in the SCN10A gene was associated with the PR interval. We examined whether the PR prolonging allele (A allele) in the SCN10A gene may be associated with cardiac conduction abnormalities in HCM patients.We genotyped the polymorphism in 149 HCM patients. Conduction abnormalities were defined as first-degree heart block, bundle-branch block, and bifascicular heart block. Patients were divided into two groups: group A consisted of 122 patients (82%) without a conduction abnormality; and group B consisted of 27 patients (18%) with one or more cardiac conduction abnormalities. The frequency distribution of the SCN10A genotypes (G/G, G/A, and A/A) among the patients with HCM was 71%, 26%, and 3%, respectively. A cardiac conduction abnormality was documented in 9% with G/G and 40% with G/A or A/A. There was a significant difference in the genotype distribution between the two groups (P = 0.0002). In the dominant A allele model, there was a significant difference in genotypes between the two groups (P < 0.0001). In addition, the A allele remained significant after adjusting for other covariates in a multivariate model (odds ratio = 6.30 [95% confidence interval: 2.24 to 19.09], P = 0.0005).The rs6795970 in the SCN10A gene, which is reported to carry a high risk of heart block, might be associated with cardiac conduction abnormalities in HCM patients.

Perivascular Adipose Tissue Angiotensin II Type 1 Receptor Promotes Vascular Inflammation and Aneurysm FormationNovelty and Significance

Perivascular adipose tissue exhibits characteristics of active local inflammation, which contributes to the development of atherosclerotic disease as a complication of obesity/metabolic syndrome. However, the precise role of perivascular adipose tissue in the progression of abdominal aortic aneurysm remains unclear. To test the hypothesis that genetic deletion of angiotensin II type 1a (AT1a) receptor in perivascular visceral adipose tissue (VAT) can attenuate aortic aneurysm formation in apolipoprotein E–deficient (ApoE−/−) mice, we performed adipose tissue transplantation experiments by using an angiotensin II–induced aneurysm murine model, in which we transplanted VAT from ApoE−/− or ApoE−/− AT1a−/− donor mice onto the abdominal aorta of ApoE−/− recipient mice. Compared with ApoE−/− VAT transplantation, ApoE−/− AT1a−/− VAT transplantation markedly attenuated aortic aneurysm formation, macrophage infiltration, and gelatinolytic activity in the abdominal aorta. AT1a receptor activation led to the polarization of macrophages in perivascular VAT toward the proinflammatory phenotype. Moreover, osteopontin expression and gelatinolytic activity were considerably lower in ApoE−/− AT1a−/− perivascular VAT than in ApoE−/− perivascular VAT, and angiotensin II–induced osteopontin secretion from adipocytes was eliminated after deletion of AT1a receptor in adipocytes. Notably, induction of macrophage migration by conditioned medium from angiotensin II–stimulated wild-type adipocytes was suppressed by treatment with an osteopontin-neutralizing antibody, and ApoE−/− OPN−/− VAT transplantation more potently attenuated aortic aneurysm formation than ApoE−/− VAT transplantation. Our findings indicate a previously unrecognized effect of AT1a receptor in perivascular VAT on the pathogenesis of abdominal aortic aneurysm.

Intracoronary Optical Coherence Tomography-Derived Virtual Fractional Flow Reserve for the Assessment of Coronary Artery Disease

Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Optical coherence tomography (OCT) provides accurate visualization of coronary artery morphology. The aim of this study was to investigate the relation between FFR and OCT-derived FFR. We retrospectively analyzed 31 lesions (25 left anterior descending arteries, 2 left circumflex arteries, and 4 right coronary arteries) in 31 patients with moderate-to-severe coronary stenosis, who underwent OCT and FFR measurements simultaneously. OCT-derived FFR was calculated by the original algorithm, which was calculated using the following equation based on fluid dynamics: ΔP = FV + SV2, where V is the flow velocity, F is the coefficient of pressure loss because of viscous friction (Poiseuille resistance), and S is the coefficient of local pressure loss because of abrupt enhancement (flow separation). Mean values of % diameter stenosis by quantitative coronary angiography and FFR were 55.2 ± 14.0% and 0.70 ± 0.14, respectively. OCT-derived FFR showed a stronger linear correlation with FFR measurements (r = 0.89, p <0.001; root mean square error = 0.062 FFR units) than quantitative coronary angiography % diameter stenosis (r = -0.65, p <0.001), OCT measurements of minimum lumen area (r = 0.68, p <0.001), and % area stenosis (r = -0.70, p <0.001). OCT-derived FFR has the potential to become an alternative method for the assessment of functional myocardial ischemia, and may elucidate the relation between coronary morphology and FFR.

Clinical Significance of Peripheral Endothelial Function for Left Atrial Blood Stagnation in Nonvalvular Atrial Fibrillation Patients With Low-to-Intermediate Stroke Risk

BACKGROUND In patients who have atrial fibrillation (AF) with CHADS2score of 0-1 (categorized as low-to-intermediate risk), there is little information on stratifying the risk of stroke. This study aimed to determine whether impaired endothelial function assessed by reactive hyperemia-peripheral arterial tonometry (RH-PAT) predicted left atrial blood stagnation in these patients. METHODSANDRESULTS We enrolled 81 consecutive patients with nonvalvular AF. The reactive hyperemia index (RHI) was measured using RH-PAT. Transesophageal echocardiography was performed to determine spontaneous echo contrast (SEC) before direct-current cardioversion or radiofrequency catheter ablation. SEC was found in 49 patients (60%). The RHI was significantly lower in patients with than without SEC. Multivariate analysis demonstrated that RHI was one of the independent determinants of SEC (OR per 0.1, 1.26; 95% CI, 1.11-1.49; P=0.002) in all patients. In addition, RHI was a significant determinant of SEC (AUC, 0.73; 95% CI, 0.63-0.89; P=0.0017) in patients with low-to-intermediate risk. At an RHI cut-off <1.62, the sensitivity and specificity for the identification of patients with SEC were 58% and 89%, respectively. CONCLUSIONS Impaired endothelial function assessed by RH-PAT might help to predict the presence of SEC in patients with low-to-intermediate risk of stroke. (Circ J 2016; 80: 2117-2123).

A Novel Truncating LMNA Mutation in Patients with Cardiac Conduction Disorders and Dilated Cardiomyopathy

The cardiac phenotype of laminopathies is characterized by cardiac conduction disorders (CCDs) and dilated cardiomyopathy (DCM). Although laminopathies have been considered monogenic, they exhibit a remarkable degree of clinical variability. This case series aimed to detect the causal mutation and to investigate the causes of clinical variability in a Japanese family with inherited CCD and DCM.Of the five family members investigated, four had either CCD/DCM or CCD alone, while one subject had no cardiovascular disease and acted as a normal control. We performed targeted resequencing of 174 inherited cardiovascular disease-associated genes in this family and pathological mutations were confirmed using Sanger sequencing. The degree of clinical severity and variability were also evaluated using long-term medical records. We discovered a novel heterozygous truncating lamin A/C (LMNA) mutation (c.774delG) in all four subjects with CCD. Because this mutation was predicted to cause a frameshift mutation and premature termination (p.Gln258HisfsTer222) in LMNA, we believe that this LMNA mutation was the causal mutation in this family with CCD and laminopathies. In addition, gender-specific intra-familiar clinical variability was observed in this Japanese family where affected males exhibited an earlier onset of CCD and more severe DCM compared to affected females. Using targeted resequencing, we discovered a novel truncating LMNA mutation associated with CCD and DCM in this family characterized by gender differences in clinical severity in LMNA carriers. Our results suggest that in patients with laminopathy, clinical severity may be the result of multiple factors.

Estimation of myocardial flow reserve utilizing an ultrafast cardiac SPECT: Comparison with coronary angiography, fractional flow reserve, and the SYNTAX score

BACKGROUND Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). METHODS We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99mTc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFRi) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. RESULTS The global MFRi was 1.46 (1.16-1.76), 1.33 (1.12-1.54), and 1.18 (1.01-1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFRi was lower than that in 0-VD (1.63 [1.22-2.04], P<0.0001) and 1-VD (P=0.003). Multivariate logistic regression analysis for 3-VD showed significant associations with smoking history (odds ratio [OR]: 4.4 [0.4-8.4]), left ventricular ejection fraction (OR: 61.6 [57.5-66.0]), and global MFRi (OR: 119.6 [111.5-127.7], P=0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFRi (r=0.62, P=0.008), and the SYNTAX score correlated negatively with global MFRi (r=0.567, P=0.0003). CONCLUSION We developed and validated a clinically available method for MFR quantification by dynamic 99mTc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD.

Cardiac magnetic resonance imaging for assessment of steroid therapy in a patient with cardiac sarcoidosis and a magnetic resonance-conditional pacemaker

Cardiacmagnetic resonance imaging for assessment of steroid therapy in a patient with cardiac sarcoidosis and a magnetic resonance-conditional pacemaker Tamami Kono ⁎, Akiyoshi Ogimoto , Makoto Saito , Kaori Fujimoto , Akira Fujii , Teruyoshi Uetani , Takayuki Nagai , Kazuhisa Nishimura , Katsuji Inoue , Jun Suzuki , Takafumi Okura , Tomoyuki Kido , Masao Miyagawa , Teruhito Mochizuki , Jitsuo Higaki a

Late iodine enhancement computed tomography with image subtraction for assessment of myocardial infarction

AbstractObjectiveTo evaluate the feasibility of image subtraction in late iodine enhancement CT (LIE-CT) for assessment of myocardial infarction (MI).MethodsA comprehensive cardiac CT protocol and late gadolinium enhancement MRI (LGE-MRI) was used to assess coronary artery disease in 27 patients. LIE-CT was performed after stress CT perfusion (CTP) and CT angiography. Subtraction LIE-CT was created by subtracting the mask volume of the left ventricle (LV) cavity from the original LIE-CT using CTP dataset. The %MI volume was quantified as the ratio of LIE to entire LV volume, and transmural extent (TME) of LIE was classified as 0%, 1–24%, 25–49%, 50–74% or 75–100%. These results were compared with LGE-MRI using the Spearman rank test, Bland-Altman method and chi-square test.ResultsOne hundred twenty-five (29%) of 432 segments were positive on LGE-MRI. Correlation coefficients for original and subtraction LIE-CT to LGE-MRI were 0.79 and 0.85 for %MI volume. Concordances of the 5-point grading scale between original and subtraction LIE-CT with LGE-MRI were 75% and 84% for TME; concordance was significantly improved using the subtraction technique (p <0.05).ConclusionSubtraction LIE-CT allowed more accurate assessment of MI extent than the original LIE-CT.Key Points• Subtraction LIE-CT allows for accurate assessment of the extent of myocardial infarction. • Subtraction LIE-CT shows a close correlation with LGE-MRI in %MI volume. • Subtraction LIE-CT has significantly higher concordance with TME assessment than original LIE-CT.

Incremental value of left atrial active function measured by speckle tracking echocardiography in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) impairs left ventricular (LV) diastolic function leading to left atrial (LA) dilatation. Because Doppler echocardiography cannot accurately assess LV diastolic function in hearts with heterogeneous hypertrophy, assessment of LA function might be useful for risk stratification of patients with HCM. This study aimed to elucidate the impact of LA function on outcome in patients with patients.