Hiroshi Kamihata

Angiotensin II Type 2 Receptor Is Upregulated in Human Heart With Interstitial Fibrosis, and Cardiac Fibroblasts Are the Major Cell Type for Its Expression

The expression pattern of angiotensin (Ang) II type 2 receptor (AT2-R) in the remodeling process of human left ventricles (LVs) remains poorly defined. We analyzed its expression at protein, mRNA, and cellular levels using autopsy, biopsy, or operation LV samples from patients with failing hearts caused by acute (AMI) or old (OMI) myocardial infarction and idiopathic dilated cardiomyopathy (DCM) and also examined functional biochemical responses of failing hearts to Ang II. In autopsy samples from the nonfailing heart group, the ratio of AT1-R and AT2-R was 59% and 41%, respectively. The expression of AT2-R was markedly increased in DCM hearts at protein (3.5-fold) and mRNA (3.1-fold) levels compared with AMI or OMI. AT1-R protein and mRNA levels in AMI hearts showed 1.5- and 2.1-fold increases, respectively, whereas in OMI and DCM hearts, AT1-R expression was significantly downregulated. AT1-R-mediated response in inositol phosphate production was significantly attenuated in LV homogenate from failing hearts compared with nonfailing hearts. AT2-R sites were highly localized in the interstitial region in either nonfailing or failing heart, whereas AT1-R was evenly distributed over myocardium at lower densities. Mitogen-activated protein kinase (MAPK) activation by Ang II was significantly decreased in fibroblast compartment from the failing hearts, and pretreatment with AT2-R antagonist caused an additional significant increase in Ang II-induced MAPK activity (36%). Cardiac hypertrophy suggested by atrial and brain natriuretic peptide levels was comparably increased in OMI and DCM, whereas accumulation of matrix proteins such as collagen type 1 and fibronectin was much more prominent in DCM than in OMI. These findings demonstrate that (1) AT2-R expression is upregulated in failing hearts, and fibroblasts present in the interstitial regions are the major cell type responsible for its expression, (2) AT2-R present in the fibroblasts exerts an inhibitory effect on Ang II-induced mitogen signals, and (3) AT1-R in atrial and LV tissues was downregulated during chronic heart failure, and AT1-R-mediated functional biochemical responsiveness was decreased in the failing hearts. Thus, the expression level of AT2-R is likely determined by the extent of interstitial fibrosis associated with heart failure, and the expression and function of AT1-R and AT2-R are differentially regulated in failing human hearts.

Improvement of Collateral Perfusion and Regional Function by Implantation of Peripheral Blood Mononuclear Cells Into Ischemic Hibernating Myocardium

Objective—This study was performed to evaluate the angiogenic effect of implantation of peripheral blood mononuclear cells (PB-MNCs) compared with bone marrow mononuclear cells (BM-MNCs) into ischemic hibernating myocardium. Methods and Results—A NOGA electromechanical system was used to map the hibernating region and to inject cells. PB-MNCs and BM-MNCs contained similar levels of vascular endothelial growth factor and basic fibroblast growth factor, whereas contents of angiogenic cytokines (interleukin-1&bgr; and tumor necrosis factor-&agr;) were larger in PB-MNCs. Numbers of endothelial progenitors were ≈500-fold higher in BM-MNCs. In BM-MNC–implanted myocardia of pigs, an increase in systolic function (ejection fraction from 33% to 52%) and regional blood flow (2.1-fold) and a reduction of the ischemic area (from 29% to 8%) were observed. PB-MNC implantation reduced the ischemic area (from 31% to 17%), the extent of which was less than that seen with BM-MNCs. In saline-implanted myocardium, the ischemic area expanded (from 28% to 38%), and systolic function deteriorated. Angiography revealed an increase in collateral vessel formation by PB-MNC or BM-MNC implantation. Capillary numbers were increased 2.6- and 1.7-fold by BM-MNC and PB-MNC implantation, respectively. BM-MNCs but not PB-MNCs were incorporated into neocapillaries. Conclusions—Catheter-based implantation of PB-MNCs can effectively improve collateral perfusion and regional function in hibernating ischemic myocardium by its ability to mainly supply angiogenic factors and cytokines.

TIMI frame count immediately after primary coronary angioplasty as a predictor of functional recovery in patients with TIMI 3 reperfused acute myocardial infarction

OBJECTIVES The purpose of this study was to evaluate whether higher coronary blood flow, estimated by the corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (CTFC), is related to better functional and clinical outcome after successful percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI). BACKGROUND Experimental studies have found that functional recovery of the infarcted myocardium was associated with increased blood flow (reactive hyperemia) to the infarcted bed shortly after reperfusion. METHODS We measured CTFC immediately after successful (TIMI 3) primary PTCA in 104 consecutive patients with their first AMI. Wall motion score index (WMSI) and the presence of pericardial effusion were assessed by two-dimensional echocardiography before and one month after PTCA. RESULTS The patients were divided into two groups according to mean CTFC for corresponding coronary artery of the control group: TIMI 3 slow group (45 patients, 40 > CTFC > or = 23) and TIMI 3 fast group (59 patients, CTFC < 23). There were no significant differences in the baseline characteristics and WMSI before reperfusion between the two groups. Improvement of WMSI in the TIMI 3 fast group was significantly greater than that of the TIMI 3 slow group (1.33 +/- 0.52 vs. 0.60 +/- 0.34, p < 0.001). Pericardial effusion and intractable heart failure were observed more frequently in the TIMI 3 slow group than in the TIMI 3 fast group (27 vs. 10%; p < 0.05, 36 vs. 17%; p < 0.05). Corrected TIMI frame count, assessed as a continuous variable, had a significant correlation with the change in WMSI (r = 0.60, p < 0.001) after adjusting for age, gender, history of hypertension, history of diabetes, elapsed time to PTCA, collateral grade, presence of antegrade flow before PTCA and number of diseased vessels. CONCLUSIONS Lower CTFC of the infarct-related artery immediately after PTCA was associated with greater functional recovery; and hence, CTFC can predict clinical and functional outcome in patients with successful PTCA.

Contrast-Induced Nephropathy in Patients Undergoing Emergency Percutaneous Coronary Intervention for Acute Coronary Syndrome

Contrast-induced nephropathy (CIN) is associated with significantly increased morbidity and mortality after coronary angiography and percutaneous coronary intervention (PCI). The aim of the present study was to assess the clinical features and in-hospital outcomes of CIN after emergency PCI. The serum creatinine (SCr) concentration was measured from days 0 to 30 in 338 consecutive patients with acute coronary syndrome undergoing emergency PCI. CIN was defined as an increase in SCr of >25% or >0.5 mg/dl within 2 days after PCI. Overall, 94 patients (28%) developed CIN. The mean SCr on admission was not significantly different between patients with CIN and those without CIN. The CIN group had significantly greater SCr at days 1, 2, and 30 than did the no CIN group. Multivariate analysis showed female gender (odds ratio [OR] 2.38, 95% confidence interval [CI] 1.12 to 5.07, p = 0.025), a culprit lesion in the left anterior descending artery (OR 2.37, 95% CI 1.31 to 4.27, p = 0.0042), contrast agent volume >200 ml (OR 3.60, 95% CI 1.96 to 6.62, p <0.001) and end-diastolic pulmonary arterial pressure >15 mm Hg (OR 2.03, 95% CI 1.02 to 4.04, p <0.01) to all correlate independently with CIN. The in-hospital mortality rate was greater in the CIN group than in the no CIN group (9.6% vs 3.3%, respectively; p = 0.025). In conclusion, CIN is a frequent complication of emergency PCI for acute coronary syndrome and is associated with a greater mortality rate and persistent renal dysfunction.

Increased level of oxidized LDL-dependent monocyte-derived microparticles in acute coronary syndrome

We measured and compared the levels of plasma soluble (s) P-selectin, sCD40L, platelet-derived microparticles (PDMP), monocyte-derived microparticles (MDMP), and anti-oxidized LDL antibody, to obtain a better understanding of their potential contribution to vascular complications in acute coronary syndrome (ACS). The concentrations of sP-selectin, sCD40L, PDMP, and MDMP in ACS patients were significantly higher than those in normal controls and patients with stable angina. When levels of these markers were compared with differences in concentration of anti-oxidized LDL antibody, all markers were significantly higher in ACS patients with a high level of anti-oxidized LDL antibody. Next, a monocytic cell line (THP-1) was incubated with high shear stress-induced platelet aggregates and PDMP. After incubation,THP-1 cells generated tissue factor-expressing MDMPs. This finding was particularly significant in the presence of oxidized LDL. These findings suggest that elevated levels of MDMPs may be a sign of atherosclerotic development in ACS patients, particularly those who exhibit anti-oxidized LDL antibodies.

Urinary liver-type fatty acid-binding protein level as a predictive biomarker of contrast-induced acute kidney injury.

Eur J Clin Invest 2012; 42 (5): 557–563

Prevention of contrast-induced nephropathy by chronic pravastatin treatment in patients with cardiovascular disease and renal insufficiency

BACKGROUND Contrast-induced nephropathy (CIN) is known to increase morbidity and mortality of cardiovascular disease. Recent studies have shown statins prevented CIN after contrast media exposure, but optimal statin type and dosage are still unknown. PURPOSE The aims of the present study were to evaluate whether chronic pravastatin treatment before scheduled coronary angiography or percutaneous coronary intervention could reduce the incidence of CIN and to elucidate the factors related to CIN in patients with renal insufficiency. METHODS We studied 431 consecutive patients with renal insufficiency. One hundred ninety-four patients were receiving pravastatin treatment as standard chronic treatment of hypercholesterolemia. Serum creatinine levels were measured at baseline (pre-procedure) and within 48 h after contrast media exposure (peak post-procedure). CIN was defined as an increase in the serum creatinine values of > or = 25% or > or = 0.5 mg/dl after contrast media exposure. Logistic regression analysis was performed to evaluate the important factors related to CIN using four variables: age, pravastatin, pre-procedure serum creatinine, and contrast volume. RESULTS CIN was observed in 36 patients (8.4%). Patients without pravastatin (p<0.01), high level pre-procedure serum creatinine (p<0.01), and high contrast volume (p=0.034) had a significantly higher incidence of CIN. Logistic regression analysis revealed that pravastatin treatment (chi(2)=6.549, p=0.011, odds ratio=0.34), pre-procedure serum creatinine (chi(2)=6.294, p=0.009, odds ratio=2.78), and contrast volume (chi(2)=4.484, p=0.034, odds ratio=1.01) were independently related to the decreased risk of CIN. CONCLUSIONS Chronic pravastatin treatment before contrast media exposure was important for preventing CIN in patients with renal insufficiency. Also, reducing the dose of contrast media was important for preventing CIN in patients with high-baseline serum creatinine levels.

A new protocol using sodium bicarbonate for the prevention of contrast-induced nephropathy in patients undergoing coronary angiography.

Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality rates. Although a previous study reported that pretreatment with sodium bicarbonate is more effective than sodium chloride for prophylaxis of CIN, this has not been a universal finding. We performed a prospective randomized trial to investigate whether CIN can be avoided using sodium bicarbonate. In total 155 patients with a glomerular filtration rate (GFR) <60 ml/min/1.73 m(2) who were undergoing coronary angiography were enrolled. We assigned patients to sodium chloride plus sodium bicarbonate (bicarbonate group, n = 78) or sodium chloride alone (chloride group, n = 77). Infusion of sodium bicarbonate at 1 ml/kg/hour continued from 3 hours before to 6 hours after coronary angiography. CIN was defined as a 25% increase in serum creatinine from baseline value or an absolute increase of ≥0.5 mg/dl, which appeared within 2 days of contrast. Baseline GFR was not significantly different between the 2 groups. Patients in the bicarbonate group had a higher GFR than those in the chloride group on day 2 (45.8 ± 13.4 vs 40.9 ± 14.6 ml/min/1.73 m(2), p = 0.031) and at 1 month (49.5 ± 14.7 vs 43.7 ± 15.5 ml/min/1.73 m(2), p = 0.019). CIN occurred in 10 patients (13%) in the chloride group but in only 2 patients (2.6%) in the bicarbonate group (p = 0.012). Sodium chloride plus sodium bicarbonate is more effective than sodium chloride alone for prophylaxis of CIN and can lead to retention of better long-term renal function.

Urinary excretion of biopyrrins, oxidative metabolites of bilirubin, increases after spasm provocation tests in patients with coronary spastic angina.

BACKGROUND Bilirubin apparently functions as an antioxidant in vivo by reacting with reactive oxygen species, and, as a result, becomes oxidized. The urinary excretion of oxidative metabolites of bilirubin, biopyrrins, could be a biological marker for in vivo production of reactive oxygen species. The purpose of this study was to examine the extent of oxidative stress in patients with possible ischemic heart diseases (n=44) by measuring urinary biopyrrins by enzyme-linked immunosorbent assay before and after the spasm provocation test (SPT). METHODS Spot urine samples were collected five times; 1 day before, in the morning just before, immediately after, 6 h after, and 1 day after the SPT. Nineteen patients were positive to SPT judged from the specific changes in electrocardiogram for myocardial ischemia following intracoronary injections of ergonovine. RESULTS The baseline data such as age, sex, number of risk factors and concentrations of serum bilirubin, and the measured hemodynamic parameters of heart rate, blood pressure, left ventricular end-diastolic pressure and left ventricular ejection fraction were not different between the positive and negative groups. The baseline concentrations of biopyrrins during the control period were not significantly different between the two groups. However, they increased significantly after the SPT, thereby the magnitude of increases immediately after and 6 h after the SPT were significantly (P<0.001 and P<0.01, respectively) greater in the positive group than in the negative. CONCLUSION The present findings strongly suggest that coronary arterial occlusion augments production of biopyrrins, which indicates exposure to oxidative stress in patients with ischemic heart diseases.

Association of Platelet-Derived Microparticles With C-C Chemokines on Vascular Complication in Patients With Acute Myocardial Infarction

The levels of platelet-derived microparticles (PDMPs), platelet activation markers (P-selectin, CD63, and PAC-1 on activated platelets), and C-C chemokines (monocyte chemotactic peptide [MCP]-1 and regulated on activation normally T-cell expressed and secreted [RANTES] were measured and compared in patients with acute myocardial infarction (AMI) or stable pectoris angina. These substances are thought to participate in the development of complications in patients with AMI. The percentage binding of anti-P-selectin, CD63, and PAC-1 antibody to platelets, and the levels of PDMPs (per 104 platelets) were higher in the patients with AMI than in those with stable pectoris angina (P-selectin, 23.1% 2.1% vs. 10.3% 1.2%, p<0.001; CD63, 24.6% 3.3% vs. 11.2% 3.1%, p<0.01; PAC-1, 14.1% 1.7% vs. 9.3% 2.1%, p<0.05; PDMPs, 613 71 vs. 413 55, p<0.01). There were no differences in platelet levels of GPIIb/IIIa and GPIb between groups. Levels of MCP-1 and RANTES were higher in the patients with AMI than in patients with stable pectoris angina (MCP-1, 430 3 vs. 265 23, p<0.01; RANTES, 175 32 vs. 8829, p<0.001). The effects of percutaneous transluminal coronary angioplasty (PTCA) on the levels of these agents in patients with AMI were studied. Platelet activation markers were significantly decreased in patients with AMI after PTCA. RANTES level was also significantly decreased after treatment, but MCP-1 level was not changed. In addition, this tendency was clearer in STENT patients. These findings suggest that in patients with AMI PTCA, particularly STENT, may prevent the development of complications in which activated platelet and RANTES participate.