Keisuke Ohba

A dipeptidyl peptidase-4 inhibitor, des-fluoro-sitagliptin, improves endothelial function and reduces atherosclerotic lesion formation in apolipoprotein E-deficient mice.

OBJECTIVES The aim of this study was to investigate the antiatherogenic effects of the dipeptidyl peptidase-4 inhibitor, des-fluoro-sitagliptin (DFS). BACKGROUND The new class of anti-type 2 diabetes drugs, dipeptidyl peptidase-4 inhibitors, improves glucose metabolism by increasing levels of active glucagon-like peptide (GLP)-1. METHODS Endothelial function was examined by acetylcholine-induced endothelium-dependent vasorelaxation using aortic rings and atherosclerotic lesion development in the entire aorta in apolipoprotein E-deficient mice fed a high-fat diet with or without DFS, and the antiatherogenic effects of DFS were investigated in cultured human macrophages and endothelial cells. Plasma levels of active GLP-1 were measured in patients with or without coronary artery disease. RESULTS DFS significantly improved endothelial dysfunction (89.9 ± 3.9% vs. 79.2 ± 4.3% relaxation at 10(-4) mol/l acetylcholine, p < 0.05) associated with increased endothelial nitric oxide synthase phosphorylation and reduced atherosclerotic lesion area (17.7% [15.6% to 25.8%] vs. 24.6% [19.3% to 34.6%], p < 0.01) compared with vehicle treatment. In cultured human macrophages, DFS significantly increased GLP-1-induced cytosolic levels of cyclic adenosine monophosphate compared with GLP-1 alone, resulted in inhibiting phosphorylation of c-jun N-terminal kinase and extracellular signal-regulated kinase 1/2 and nuclear factor-kappa B p65 nuclear translocation through the cyclic adenosine monophosphate/protein kinase A pathway, and suppressed proinflammatory cytokines (i.e., interleukin-1-beta, interleukin-6, and tumor necrosis factor-alpha) and monocyte chemoattractant protein-1 production in response to lipopolysaccharide. DFS-enhanced GLP-1 activity sustained endothelial nitric oxide synthase phosphorylation and decreased endothelial senescence and apoptosis compared with GLP-1 alone. In the human study, fasting levels of active GLP-1 were significantly lower in patients with coronary artery disease than those without (3.10 pmol/l [2.40 to 3.62 pmol/l] vs. 4.00 pmol/l [3.10 to 5.90 pmol/l], p < 0.001). CONCLUSIONS A DPP-4 inhibitor, DFS, exhibited antiatherogenic effects through augmenting GLP-1 activity in macrophages and endothelium.

Significance of a Multiple Biomarkers Strategy Including Endothelial Dysfunction to Improve Risk Stratification for Cardiovascular Events in Patients at High Risk for Coronary Heart Disease

OBJECTIVES We investigated whether a multiple biomarkers strategy that includes plasma levels of endothelium-derived microparticles (EMP), reflecting endothelial dysfunction, can improve prediction of future cardiovascular events in patients at high risk for coronary heart disease (CHD). BACKGROUND Detailed risk stratification using multiple biomarkers can provide clinical benefits in high-risk patients. Endothelial dysfunction has been described as a predictor of cardiovascular complications. METHODS We measured 3 biomarkers in 488 consecutive patients with various CHD risks: B-type natriuretic peptide (BNP), high-sensitivity C-reactive protein (hsCRP), and EMP. We followed 387 stable patients at high risk for CHD and examined future cardiovascular events. RESULTS During a mean follow-up of 36 months, 55 patients developed cardiovascular events. Multivariate Cox proportional hazards analysis adjusted for established risk factors identified age, BNP, hsCRP, and EMP as significant and independent predictors of future cardiovascular events (age: hazard ratio [HR]: 1.042, 95% confidence interval [CI]: 1.007 to 1.080, p = 0.02; BNP: HR: 1.242, 95% CI: 1.004 to 1.536, p = 0.046; hsCRP: HR: 1.468, 95% CI: 1.150 to 1.875, p = 0.002; EMP: HR: 1.345, 95% CI: 1.094 to 1.652, p = 0.005). The C statistics for cardiovascular events increased when each biomarker or combinations of biomarkers were added to the Framingham risk model (C statistics: Framingham risk model alone 0.636, Framingham risk + BNP 0.695, Framingham risk + hsCRP 0.696, Framingham risk + EMP 0.682, and Framingham risk + BNP + hsCRP + EMP 0.763). CONCLUSIONS The assessment of endothelial dysfunction by plasma levels of EMP can independently predict future cardiovascular events in patients at high risk for CHD. A multiple biomarkers strategy that includes endothelial dysfunction assessed by EMP can identify patients vulnerable to cardiovascular disease. (University Hospital Medical Information Network number: UMIN000000876).

Digital assessment of endothelial function and ischemic heart disease in women.

OBJECTIVES We investigated the utility of digital reactive hyperemia peripheral arterial tonometry (RH-PAT) in predicting ischemic heart disease (IHD), including obstructive coronary artery disease (CAD) and nonobstructive coronary artery disease (NOCAD), in women. BACKGROUND IHD is the leading cause of mortality, and its pathogenesis is diverse in women. Fingertip RH-PAT is a new device that provides noninvasive, automatic, and quantitative evaluation of endothelial dysfunction. METHODS RH-PAT was measured using Endo-PAT2000 (Itamar Medical, Caesarea, Israel) before cardiac catheterization in 140 stable women scheduled for hospitalization to examine chest pain. NOCAD was diagnosed by angiography with measurement of coronary blood flow and cardiac lactate production during intracoronary acetylcholine provocation test and cardiac scintigraphy with stress tests. RESULTS Sixty-eight women (49%) had obstructive CAD and 42 women (30%) had NOCAD. RH-PAT indexes were significantly attenuated in both obstructive CAD and NOCAD as compared with non-IHD (n = 30) (obstructive CAD: median 1.57, interquartile range [IQR] 1.42 to 1.76; NOCAD: median 1.58, IQR 1.41 to 1.78; non-IHD: median 2.15, IQR 1.85 to 2.48, p < 0.001). By multivariate logistic regression analysis, only RH-PAT index was significantly associated with IHD, including obstructive CAD and NOCAD (odds ratio 0.51; 95% confidence interval: 0.38 to 0.68; p < 0.001). In receiver-operating characteristic analysis, RH-PAT index was a significant predictor of IHD (area under the curve 0.86; p < 0.001). Furthermore, only RH-PAT was useful for the prediction of NOCAD after excluding obstructive CAD (area under the curve 0.85; p < 0.001; RH-PAT index of <1.82 had 81% sensitivity and 80% specificity). CONCLUSIONS RH-PAT indexes were significantly attenuated in women with IHD. Digital RH-PAT can predict patients with IHD, especially NOCAD before angiography. RH-PAT is potentially useful for identifying high-risk women for IHD. (Endothelial Dysfunction and Coronary Artery Spasm; NCT00619294).

Pentraxin 3 Is a New Inflammatory Marker Correlated With Left Ventricular Diastolic Dysfunction and Heart Failure With Normal Ejection Fraction

OBJECTIVES This study investigated the clinical significance of plasma pentraxin 3 (PTX3) levels in patients with heart failure with normal ejection fraction (HFNEF) and whether PTX3 is produced from coronary circulation. BACKGROUND Pentraxin 3 is a novel inflammatory marker and a member of pentraxin superfamily including C-reactive protein (CRP). The relationship between inflammatory markers and HFNEF remains unclear. METHODS We measured peripheral blood levels of PTX3, high-sensitivity CRP, tumor necrosis factor-alpha, and interleukin-6 in 323 patients comprising 82 HFNEF, 70 heart failure (HF) with reduced EF, and 171 non-HF patients. Levels of PTX3 were also measured at the aortic root and the coronary sinus in 75 patients. RESULTS The levels of PTX3, tumor necrosis factor-alpha, and interleukin-6, but not high-sensitivity CRP, were significantly higher in HFNEF patients than in non-HF patients. Multivariate logistic regression analysis identified only high levels of PTX3 as the independent inflammatory marker correlated with the presence of HFNEF in patients with normal left ventricular (LV) EF (odds ratio [OR]: 1.49, 95% confidence interval [CI]: 1.11 to 1.98, p < 0.01) and with the presence of left ventricular diastolic dysfunction (LVDD) in non-HF patients (OR: 1.23, 95% CI: 1.02 to 1.50, p < 0.05). Levels of PTX3 at the coronary sinus were significantly higher than at the aortic root in HFNEF patients (p < 0.05) and in non-HF patients with LVDD (p < 0.01), but not different in non-HF patients without LVDD (p = 0.33). CONCLUSIONS Pentraxin 3 is significantly elevated in HFNEF patients and produced in the coronary circulation in patients with LVDD. Pentraxin 3, but not high-sensitivity CRP, is an independent inflammatory marker correlated with the presence of LVDD and HFNEF. (The Clinical Significance of Plasma Pentraxin 3 levels for Patients with Diastolic Heart Failure; UMIN000002170).

Peripheral Endothelial Function and Cardiovascular Events in High-Risk Patients

Background Endothelial dysfunction is a key component of vascular vulnerability. Reactive hyperemia index (RHI), as assessed by the peripheral arterial tonometry, can noninvasively evaluate endothelial function. This study was designed to determine the additional prognostic value of endothelial function to the Synergy Between PCI With Taxus and Cardiac Surgery Score (SYNTAXsc) and the Framingham Risk Score (FRS) in predicting cardiovascular events in high‐risk patients. Methods and Results We undertook a two‐center prospective study in 528 stable patients at high‐risk for cardiovascular events from the years 2006–2011. The RHI was measured before coronary angiography and coronary complexity was assessed by SYNTAXsc. After optimal therapies including coronary revascularization, there was follow‐up with patients until August 2012. Cardiovascular events consist of cardiovascular death, myocardial infarction, unstable angina, ischemic stroke, coronary revascularization, heart failure‐induced hospitalization, aortic disease, and peripheral arterial disease. During 1468 person‐years of follow‐up, 105 patients developed cardiovascular events. Multivariate Cox proportional hazards analysis identified B‐type natriuretic peptide (BNP), SYNTAXsc, and RHI as independent cardiovascular event predictors (hazard ratio [95% confidence interval]: natural logarithm of BNP per 0.1: 1.019 [1.002 to 1.037]; P=0.023, SYNTAXsc per tertile: 2.426 [1.825 to 3.225]; P<0.0001, RHI per 0.1: 0.761 [0.673 to 0.859]; P<0.0001). When RHI was added to the FRS, BNP, and SYNTAXsc, net reclassification index was significantly improved (27.5%; P<0.0001), with a significant increase in the C‐statistic (from 0.728 [0.679 to 0.778] to 0.766 [0.726 to 0.806]; P=0.031). Conclusions Advanced endothelial dysfunction significantly correlated with near future cardiovascular events in high‐risk patients. This physiological vascular measurement improved risk discrimination when added to the FRS, BNP, and SYNTAXsc. Clinical Trial Registration URL: clinicaltrials.gov (http://www.clinicaltrials.gov). Unique identifier: NCT00737945.

Association of pericardial fat accumulation rather than abdominal obesity with coronary atherosclerotic plaque formation in patients with suspected coronary artery disease

OBJECTIVES The purpose of this study was to examine the association of pericardial fat with the presence of coronary plaques. BACKGROUND Waist circumference, reflecting abdominal obesity, is a risk factor of metabolic syndrome and coronary artery disease (CAD). Adipose tissue secretes many factors implicated in atherogenesis, however, the role of pericardial fat (ectopic visceral fat around coronary arteries) in the pathogenesis of CAD is not clear. METHODS We measured total pericardial fat volume (PFV) and determined presence and characteristics of coronary plaques using 64-slice computed tomography in 171 consecutive patients suspected of CAD (101 men; mean age, 66+/-11 years, +/-SD). RESULTS PFV correlated with age (p<0.05), body mass index (p<0.05), waist circumference (p<0.01), and high-density lipoprotein cholesterol (p<0.01) by multivariate regression analysis. PFV was significantly larger in patients with coronary plaques, even nonstenotic or noncalcified ones, than those without plaques (any plaques, n=123; 201+/-71cm(3), nonstenotic plaques, n=51; 192+/-63, noncalcified plaques, n=32; 196+/-56 vs. no plaque, n=48; 144+/-45, p<0.001, respectively). Multivariate backward logistic regression analysis demonstrated that PFV, but not waist circumference, significantly associated with the presence of any coronary plaques (odds ratio [OR]; 2.876, 95% confidence interval [95% CI]; 1.614-5.125, p<0.001), nonstenotic plaques confirmed by coronary angiography (OR; 3.423, 95% CI; 1.764-6.642, p<0.001), and noncalcified plaques (OR; 3.316, 95% CI; 1.435-7.661, p<0.01). CONCLUSIONS PFV correlated significantly with the presence of nonstenotic and noncalcified coronary plaques assessed by multislice computed tomography. Pericardial fat is more highly associated with early development of CAD than simple anthropometric measures of abdominal obesity.

Prognostic value of endothelial microparticles in patients with heart failure

Heart failure (HF) is associated with endothelial dysfunction. Endothelium‐derived microparticles (EMPs) are a novel quantitative plasma marker of endothelial dysfunction. We investigated whether plasma levels of EMPs can predict future cardiovascular events in patients with HF.

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.

Pericardial fat inflammation correlates with coronary artery disease

OBJECTIVES We sought to assess the association between inflammation in pericardial fat (PF) and coronary artery disease (CAD) by pathological examination and clinical evaluation with cardiac computed tomography (CT). BACKGROUND Inflammation of adipose tissue is involved in cardio-metabolic disorders and shows high density in CT. METHODS We quantified, by immunohistochemical means, the PF inflammation in 39 autopsy cases by counting leukocyte common antigen (LCA)-positive cells. We then measured the CT density of PF in 39 patients with acute coronary syndromes and 69 patients suspected of CAD. RESULTS Pericoronary PF had significantly more LCA-positive cells in CAD autopsy cases (n=21) than non-CAD cases (n=18) (44 ± 21 vs. 24 ± 22 cells/mm(2), p=0.006). The CT density of PF around culprit lesions was significantly higher than non-culprit lesions in patients with acute coronary syndromes (-72 ± 11 vs. -82 ± 14 HU, p=0.002), which may reflect PF inflammation. Among patients suspected of CAD, the pericardial CT density gradient (PDG; difference in CT density between pericoronary PF and PF apart from coronary arteries) was significantly greater in CAD patients (n=30) than non-CAD patients (n=39) (22 ± 16 vs. 16 ± 10 HU, p=0.046). Multiple logistic regression analysis demonstrated that the PF inflammation index (PFI; PDG × PF volume, which could be the integrated index of inflammatory activity and abundance of PF) was significantly associated with the presence of CAD (odds ratio [95% confidence interval]; 1.234 [1.012-1.503] per 1000 HU cm(3), p=0.037) independent of other metabolic risk factors such as hypertension, dyslipidemia, and diabetes. CONCLUSIONS Active inflammation in PF correlates with CAD. PF inflammation may be involved in pathogenesis of CAD.

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.