Seiji Hokimoto

Expression of Angiotensin-Converting Enzyme in Remaining Viable Myocytes of Human Ventricles After Myocardial Infarction

BACKGROUND Local ACE in the heart may be important in the pathophysiological state after myocardial infarction (MI). It is unknown, however, whether ACE is expressed in myocytes of the human heart. METHODS AND RESULTS Using a newly generated polyclonal antibody to a synthetic peptide corresponding to part of the human endothelial ACE sequence, we examined the localization of ACE in left ventricles of patients (n = 10) with MI obtained at left ventricular aneurysmectomy or autopsy and in the hearts of control subjects at autopsy (n = 10). The avidinbiotinylated peroxidase complex method was used for the immunohistochemical staining for ACE. In the left ventricles, positively stained myocytes for ACE were found in 8 of the 10 patients with MI. ACE immunoreactivity was seen in the remaining viable myocytes located near the infarct scar of the aneurysmal left ventricle and in nonmyocytes such as fibroblasts, macrophages, vascular smooth muscle cells, and endothelial cells within the scarred tissue. On the other hand, no immunoreactivity for ACE was detected in the ventricular myocytes of all control hearts obtained at autopsy. CONCLUSIONS We observe immunohistochemical staining for ACE in the left ventricular myocytes of the region adjacent to the infarct scar and in nonmyocytes. These results indicate that ACE is markedly increased on the edge of the infarct scar and suggest that local ACE may be important in the ventricular remodeling after MI.

Effects of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, fluvastatin, on coronary spasm after withdrawal of calcium-channel blockers.

OBJECTIVES The purpose of this study was to determine whether a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) suppresses coronary spasm. BACKGROUND Coronary spasm is associated with endothelial dysfunction. Statins have been shown to improve endothelial function. METHODS This was a prospective, randomized, open-label, end point study. Sixty-four patients who had no significant organic coronary stenosis and in whom coronary spasm was induced by intracoronary injection of acetylcholine (ACh) were randomly assigned to fluvastatin 30 mg/day plus the conventional calcium-channel blocker (CCB) therapy (31 patients, statin group) or the conventional CCB therapy (33 patients, nonstatin group). After 6 months of treatment, the intracoronary injection of ACh was repeated and the coronary spasm was assessed. RESULTS Coronary spasm was suppressed in 16 of the 31 patients (51.5%, p < 0.0001) of the statin group and in 7 of the 33 patients (21.2%, p = 0.0110) of the nonstatin group after 6 months of treatment. Thus, the number of patients with ACh-induced coronary spasm was significantly reduced in the statin group as compared with the nonstatin group (51.6% vs. 21.2%, p = 0.0231) after 6 months of treatment. CONCLUSIONS The addition of fluvastatin 30 mg/day to the conventional CCB therapy for 6 months significantly reduced the number of patients with ACh-induced coronary spasm as compared with the conventional CCB therapy. Thus, a statin (fluvastatin) may possibly be a novel therapeutic drug for coronary spasm.

C/EBP Homologous Protein Deficiency Attenuates Myocardial Reperfusion Injury by Inhibiting Myocardial Apoptosis and Inflammation

Objective—To investigate whether and how the endoplasmic reticulum (ER) stress–induced, CCAAT/enhancer-binding protein-homologous protein (CHOP)-mediated pathway regulates myocardial ischemia/reperfusion injury. Methods and Results—Wild-type and chop-deficient mice underwent 50 minutes of left coronary artery occlusion followed by reperfusion. Expression of chop and spliced x-box binding protein-1 (sxbp1) mRNA was rapidly and significantly increased in reperfused myocardium of wild-type mice. chop-deficient mice exhibited markedly reduced injury size after reperfusion compared with wild-type mice, accompanied by a decreasing number of terminal deoxynucleotidyl transferase dUTP nick-end labeling–positive cardiomyocytes. Interestingly, myocardial inflammation, as assessed by expression of inflammatory cytokines and chemokines and numbers of infiltrated inflammatory cells, was also attenuated in chop-deficient mice. Moreover, expression of interleukin-6 mRNA in response to lipopolysaccharide was enhanced by simultaneous stimulation with thapsigargin, a potent ER stressor, in wild-type cardiomyocytes but not in chop-deficient cardiomyocytes. Finally, we found that superoxide was produced in reperfused myocardium and that intravenous administration of edaravone, a free radical scavenger, immediately before reperfusion significantly suppressed the superoxide overproduction and subsequent expression of sxbp1 and chop mRNA, followed by reduced injury size in wild-type mice. Conclusion—The ER stress–induced, CHOP-mediated pathway, which is activated in part by superoxide overproduction after reperfusion, exacerbates myocardial ischemia/reperfusion injury by inducing cardiomyocyte apoptosis and myocardial inflammation.

Impact of CYP2C19 polymorphism on residual platelet reactivity in patients with coronary heart disease during antiplatelet therapy

BACKGROUND AND PURPOSE CYP2C19*2 loss-of-function allele in Caucasians may be associated with wide interindividual variability in platelet response to clopidogrel, and the incidence of gene mutation varies with racial differences, especially between Asians and Caucasians. The aim was to examine the impact of CYP2C19 genotype on the residual platelet reactivity in Japanese patients with coronary heart disease (CHD) during antiplatelet therapy. METHODS AND RESULTS We measured the CYP2C19 genotype and platelet aggregation in 201 patients with stable CHD. Moreover, we examined the relation of CYP2C19 polymorphism to cardiovascular events in 98 patients treated with stent implantation. The distribution of CYP2C19 genotype was 37%, 33%, 11%, 11%, 7%, and 1% in CYP2C19*1/*1, *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3, respectively. Residual platelet reactivity was lower in patients during dual antiplatelet therapy (DAT) than in those with aspirin (3975 ± 1569 aggregation units minute (AU min) vs 5850 ± 938 AU min, p<0.05). In the DAT group, the platelet reactivity decreased significantly in the wild-type homozygotes (CYP2C19*1/*1), subsequently in the *2, or *3 heterozygotes (*1/*2, *1/*3), and was not well inhibited in the *2, and/or *3 homozygotes (*2/*2, *2/*3, *3/*3; 3194 ± 1570 AU min, 4148 ± 1400 AU min, and 5088 ± 1080 AU min, respectively). However, when the duration of DAT was used to divide subjects into 2 groups, <7 days, and >7 days, patients carrying the variant allele showed significantly decreased platelet reactivities at >7 days compared with those at <7 days. Moreover, the incidence of cardiovascular events was higher in patients carrying at least one variant allele than in wild-type homozygotes. CONCLUSIONS CYP2C19 polymorphism may be associated with high residual platelet reactivity and the occurrence of cardiovascular events.

Coronary Vasomotor Response to Intracoronary Acetylcholine Injection, Clinical Features, and Long-term Prognosis in 873 Consecutive Patients With Coronary Spasm: Analysis of a Single-Center Study Over 20 Years

Background The aim of this study was to elucidate the correlation between angiographic coronary vasomotor responses to intracoronary acetylcholine (ACh) injection, clinical features, and long‐term prognosis in patients with vasospastic angina (VSA). Methods and Results This is a retrospective, observational, single‐center study of 1877 consecutive patients who underwent ACh‐provocation test between January 1991 and December 2010. ACh‐provoked coronary spasm was observed in 873 of 1637 patients included in the present analysis. ACh‐positive patients were more likely to be older male smokers with dyslipidemia, to have a family history of ischemic heart disease, and to have a comorbidity of coronary epicardial stenosis than were ACh‐negative patients. ACh‐positive patients were divided into 2 groups: those with focal (total or subtotal obstruction, n=511) and those with diffuse (severe diffuse vasoconstriction, n=362) spasm patterns. Multivariable logistic regression analysis identified female sex and low comorbidity of coronary epicardial stenosis to correlate with the ACh‐provoked diffuse spasm pattern in patients with VSA. Kaplan–Meier survival curve indicated better 5‐year survival rates free from major adverse cardiovascular events in patients with diffuse spasm pattern compared with those with focal spasm pattern (P=0.019). Multivariable Cox hazard regression analysis identified diffuse spasm pattern as a negative predictor of major adverse cardiovascular events in patients with VSA. Conclusions ACh‐induced diffuse coronary spasm was frequently observed in female VSA patients free of severe coronary epicardial stenosis and was associated with better prognosis than focal spasm. These results suggest the need to identify the ACh‐provoked coronary spasm subtypes in patients with VSA.

Increased angiotensin converting enzyme activity in left ventricular aneurysm of patients after myocardial infarction

OBJECTIVE Angiotensin converting enzyme (ACE) inhibitors have been shown to improve left ventricular dysfunction and survival in patients with chronic myocardial infarction. The aim of this study was to examine the ACE activity in infarcted tissues in such patients in comparison with non-diseased tissues from control subjects obtained at necropsy. METHODS ACE activity was measured in the left ventricles and right atrial auricles of patients (n = 9) with chronic myocardial infarction obtained at left ventricular aneurysmectomy, and in the hearts of control subjects at necropsy (n = 10). RESULTS In non-diseased hearts, the ACE activity was highest in right atria and auricles [2.4(SEM 0.2), 2.2(0.3) nmol.mg-1 protein.min-1, NS, respectively], followed by left atria [1.7(0.2)], left auricles [1.5(0.1)], right ventricles [1.0(0.2)], and left ventricles [0.5(0.1)]. The ACE activity was significantly increased in aneurysmal tissues of patients with chronic myocardial infarction relative to left ventricles of control subjects [4.2(0.4) v 0.5(0.1) nmol.mg-1 protein.min-1, P < 0.01]. There was, however, no difference in the ACE activity of right atrial auricles between patients with chronic myocardial infarction and control subjects [2.8(0.5) v 2.2(0.3), NS]. In patients with chronic myocardial infarction, the ACE activity was higher in left ventricles than in right auricles (P < 0.01). The ACE activities in the infarcted and control ventricles were negatively correlated with the membrane protein content (r = -0.77, P < 0.01). CONCLUSIONS In non-diseased human hearts, the ACE activity is higher in atria than in ventricles and higher in the right than in the left ventricle. Furthermore, the ACE activity in aneurysmal left ventricular tissue after myocardial infarction is higher than in non-diseased left ventricular myocardium. These results suggest that the local ACE in the human heart may play an important role in the pathophysiological state after myocardial infarction.

Microvascular coronary artery spasm presents distinctive clinical features with endothelial dysfunction as nonobstructive coronary artery disease.

Background Angina without significant stenosis, or nonobstructive coronary artery disease, attracts clinical attention. Microvascular coronary artery spasm (microvascular CAS) can cause nonobstructive coronary artery disease. We investigated the clinical features of microvascular CAS and the therapeutic efficacy of calcium channel blockers. Methods and Results Three hundred seventy consecutive, stable patients with suspected angina presenting nonobstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test, with simultaneous measurements of transcardiac lactate production and of changes in the quantitative coronary blood flow. We diagnosed microvascular CAS according to lactate production and a decrease in coronary blood flow without epicardial vasospasm during the acetylcholine provocation test. We prospectively followed up the patients with calcium channel blockers for microvascular coronary artery disease. We identified 50 patients with microvascular CAS who demonstrated significant impairment of the endothelium-dependent vascular response, which was assessed by coronary blood flow during the acetylcholine provocation test. Administration of isosorbide dinitrate normalized the abnormal coronary flow pattern in the patients with microvascular CAS. Multivariate logistic regression analysis indicated that female sex, a lower body mass index, minor–borderline ischemic electrocardiogram findings at rest, limited–baseline diastolic-to-systolic velocity ratio, and attenuated adenosine triphosphate–induced coronary flow reserve were independently correlated with the presence of microvascular CAS. Receiver-operating characteristics curve analysis revealed that the aforementioned 5-variable model showed good correlation with the presence of microvascular CAS (area under the curve: 0.820). No patients with microvascular CAS treated with calcium channel blockers developed cardiovascular events over 47.8±27.5 months. Conclusions Microvascular CAS causes distinctive clinical features and endothelial dysfunction that are important to recognize as nonobstructive coronary artery disease so that optimal care with calcium channel blockers can be provided. Clinical Trial Registration URL: www.umin.ac.jp/ctr. Unique identifier: UMIN000003839.

Metal allergic reaction in chronic refractory in-stent restenosis

OBJECTIVES This study examined the relationship between chronic refractory (CR) in-stent restenosis (ISR) and metal allergic reaction. BACKGROUND Although drug-eluting stent reduced the restenotic event compared with bare-metal stent, the mechanism of neointimal proliferation is not clear yet; however, bare-metal stent still remains as one of the choices. METHODS Of 128 bare-metal stent implanted patients who experienced target lesion revascularization at least once, 60 patients with the second ISR (study group) and 68 patients without the second ISR (control group) were compared in terms of result from the skin patch test for metal allergic reaction. RESULTS Nickel was dominant among components of 316L stainless steel. The nickel-positive was observed in 19% (24/128) of all patients. Of 24 nickel-positive, 18 (30%) was in the study group, whereas 6 (9%) was in the control group (P=.02). According to multivariate analysis, the most significant predictor for CR-ISR was reference vessel diameter (P=.0010) followed by nickel-positive (P=.0033) and hyperlipidemia (P=.0305). The nickel-positive showed the highest odds ratio of 5.41 adjusted with confounder variables. CONCLUSION This study with the second ISR showed that nickel was a major factor for CR-ISR. Further improvement of biocompatible material is required for coronary stents and strut-coating materials even in the drug-eluting stent era.

Impact of CYP2C19 polymorphism and proton pump inhibitors on platelet reactivity to clopidogrel and clinical outcomes following stent implantation.

BACKGROUND The response to clopidogrel, and some kind of the drug interaction are multifactorial. METHODS AND RESULTS We enrolled 174 consecutive patients and determined CYP2C19 genotypes, measured platelet aggregation, and assessed the relationship between CYP2C19 genotype and platelet reactivity 24hours after clopidogrel administration, and the risk of cardiovascular events over 18months follow-up. A sub analysis examined the impact of rabeprazole, a proton pump inhibitor (PPI) less affected by CYP2C19. The CYP2C19 genotype was extensive metabolizer (EM) in 36%, intermediate metabolizer (IM) in 45%, and poor metabolizer (PM) in 19%. Platelet reactivity was significantly lower in the EM group than in the IM and PM groups (EM, IM, PM: 3560±1404, 4203±1302, 5084±1007AU•min, P<0.05). The cardiovascular event rate was higher in the IM and PM groups than in the EM group (12.7% and 12.5% vs 1.6%; Hazard ratio for IM 10.6, P=0.029; for PM 11.3, P=0.040). No differences were seen between patients taking (N=50) and not taking (N=124) rabeprazole in residual platelet aggregation (4407±1360 vs 4048±1394, AU•min, P=0.2782), or in cardiovascular events (10.0% vs 8.1%, HR 0.97, P=0.97). CONCLUSIONS CYP2C19 genotype is associated with an increased risk of cardiovascular events following stent implantation in Japanese patients.

Growth differentiation factor-15 is a useful prognostic marker in patients with heart failure with preserved ejection fraction.

BACKGROUND Circulating growth differentiation factor 15 (GDF-15) levels correlate with heart mass and fibrosis; however, little is known about its value in predicting the prognosis of patients with heart failure with preserved ejection fraction (HFpEF). METHODS We measured serum GDF-15 levels in 149 consecutive patients with left ventricular diastolic dysfunction (LVDD) and normal LV ejection fraction (>50%) and followed them for cardiovascular events. LVDD was defined according to the European Society of Cardiology guidelines. RESULTS The New York Heart Association functional class and circulating B-type natriuretic peptide (BNP) levels were significantly higher in the high-GDF-15 group (n = 75; greater than or equal to the median value [3694 pg/mL]) than in the low-GDF-15 group (n = 74). Patients were divided into HFpEF and LVDD groups according to the presence or absence of HF. Serum GDF-15 levels were significantly higher in the HFpEF group (n = 73) than in the LVDD group (n = 76) (median, 4215 [interquartile range, 3382-5287] vs 3091 [interquartile range, 2487-4217 pg/mL]; P < 0.0001). Kaplan-Meier curve analysis showed a significantly higher probability of cardiovascular events in the high-GDF-15 group than in the low-GDF-15 group for data of all patients (log-rank test P = 0.006) and data of patients in the HFpEF group only (P = 0.014). Multivariate Cox hazard analysis identified age (hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.87-0.98; P = 0.008), atrial fibrillation (HR, 7.95; 95% CI, 1.98-31.85, P = 0.003), lnBNP (HR, 3.37; 95% CI, 1.73-6.55; P < 0.0001), and GDF-15 (ln[GDF-15]) (HR, 4.74; 95% CI, 1.26-17.88, P = 0.022) as independent predictors of primary end points. CONCLUSIONS GDF-15 is a potentially useful prognostic biomarker in patients with HFpEF.