Protein kinases are involved in the cardioprotective effects activated by platelet glycoprotein IIb/IIIa inhibitor tirofiban at reperfusion in rats in vivo

The thrombolytic effect of platelet glycoprotein IIb/IIIa inhibitors (GP IIb/IIIa inhibitors) in myocardial infarction has been well established. Nevertheless, data on the mechanism of the cardioprotective effect of GP IIb/IIIa inhibitors in ischemic-reperfusion injury (IR) are lacking. Sprague-Dawley rats received 120 min of coronary ischemia and 180 min of reperfusion. A GP IIb/IIIa inhibitor was given via continuous intravenous infusion at a rate of 2 μg/kg/min 30 min prior to reperfusion with/without inhibitors of PKCε (chelerythrine), PI3 kinase and Akt (wortmannin), p38 MAPK (SB203582), p42/44 MAPK (PD98059) and ERK1/2 (u0126) 15 min prior to the GP IIb/IIIa inhibitor. Protein isolation and analysis were performed by Western blot analysis. The cardioprotective effects were measured as the ratio of myocardial necrotic area to the area at risk (AAR) and the apoptotic index (AI) calculated as the percentage of myocytes positive for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling of all myocytes stained by 4', 6-diamidino-2-phenylindole. The GP IIb/IIIa inhibitor reduced the ratio of myocardial necrotic area to AAR and AI, and also exerted an immediate cardioprotective effect by activating multiple signaling pathways including phosphorylation and activation of PKCε, PI3 kinase, Akt, p38 MAPK, p42/44 MAPK and ERK1/2. However, there were no significant increases in the phosphorylation of Raf and MEK1/2. We concluded that the GP IIb/IIIa inhibitor reduced the extent of cardiac IR and significantly ameliorate the apoptosis of myocytes in the rats. In addition, the cardioprotective effect was mediated through the activation of multiple signal transduction pathways.

Optimal Duration of Coronary Ligation and Reperfusion for Reperfusion Injury Study in a Rat Model

BACKGROUND

Reperfusion injury (RI) has an important impact on the clinical prognosis for patients with acute myocardial injury who had their coronary blood flow reestablished. However, no studies to date have investigated the timeframe of coronary occlusion and reperfusion effects on RI.

METHODS

A total of 100 rats were divided into 4 groups based on the coronary ligation period: 30, 60, 120, and 180 min, and each group was further divided into 5 subgroups with different reperfusion periods: 0, 30, 60, 120, and 180 min. R0 was the baseline of each subgroup. All animals received the same protocols for designed ligation and reperfusion periods. Evans blue and 2,3,5-triphenyltetrazolium chloride were used to distinguish different myocardial injury areas: area at risk (AAR) and myocardial necrosis. The differences of the ratios of the necrotic area to AAR between each subgroup and baseline were further averaged to calculate an overall value of each heart.

RESULTS

The relative RI percentages showed significant differences (0.8 ± 2.3%, 4.9 ± 3.3%, 10.8 ± 3.1%, and 20.3 ± 3.6% respectively, p < 0.001) at different time points of reperfusion but not at different time points of ligation (p = 0.593). The effects of different time courses in RI showed that the L120R180 group (43.4 ± 2.3%) had the highest RI difference with the baseline group.

CONCLUSIONS

Maximal RI occurred at the timeframe of L120R180 in our animal model. This result may be utilized to assess the substantial benefits of RI therapies in an experimental rat model setting.

Gout, not hyperuricemia alone, impairs left ventricular diastolic function

Introduction

Gout is a common metabolic disorder characterized by hyperuricemia and chronic inflammation. Previous studies show that hyperuricemia accelerates the occurrence and worsening of cardiovascular disease due to LV remodeling. However, it is still unclear whether hyperuricemia is the sole contributor to organic heart remodeling in patients with gout. In addition, there is a paucity of data regarding the association between LV diastolic function and gout. The objective of this study was to investigate the effects of gout on LV diastolic function.

Methods

A total of 173 patients were divided into tertiles based on the following serum uric acid (UA) levels: 1) serum UA ≤ 6.5 mg/dL (n = 54), 2) serum UA >6.5 to ≤8.5 mg/dL (n = 59), and 3) serum UA > 8.5 mg/dL (n = 60).Patients underwent a comprehensive Doppler-echocardiography examination to evaluate LV volume, systolic and diastolic function, and left atrial (LA) volume.

Results

LV diastolic parameters, including diastolic peak early transmitral flow velocity (E), late transmitral flow velocity (A), E/A, peak early diastolic mitral annular velocity (Em), late diastolic annular velocity (Am), Em/Am, E/Em, maximal LA volume index (LAVi) and prevalence of moderate to severe LV diastolic dysfunction were not significantly different between the three groups. Among the population being studied, 108 individuals received a gout diagnosis. Gout patients had greater LV end-systolic dimensions (27.08 ± 4.38 mm, p = 0.006), higher LV mass index (107.18 ± 29.51 g/m², p < 0.001), higher E/Em (10.07 ± 2.91, p = 0.008), and larger maximal LAVi (16.96 ± 7.39 mL/m², p < 0.001) than patients without gout. The prevalence of moderate to severe LV diastolic dysfunction was higher in patients with gout (23 %, p = 0.02).

Conclusions

Gout, not hyperuricemia alone, is associated with LV diastolic dysfunction and LA volume enlargement.

Coronary artery phenotypes in subjects with negative myocardial perfusion imaging and typical angina pectoris

INTRODUCTION

Limited data are available on coronary lesion morphology for patients with false-negative radionuclide findings together with typical angina symptoms.

METHODS

The study group consisted of 25 subjects with a negative pharmacological thallium (Tl)-201 single-photon emission computed tomography perfusion imaging study but typical angina symptoms and coronary artery disease (CAD) confirmed by coronary angiography. The control group included 690 subjects with a positive pharmacological Tl-201 single-photon emission computed tomography study and CAD.

RESULTS

The study group showed a significantly older and higher female ratio than the control group. Significant differences were found between the 2 groups in the presence of current smoking status and hypertension. A noticeably higher percentage of positive metabolic syndrome ratio, number of metabolic syndrome components, high waist-to-hip ratio percentage and high waist circumference percentage in the study group. The study group was noticeably lower in mean numbers of culprit vessel involvement and mean lesion numbers than the control group. There were more individuals with type A classification and a lower proportion of complex stenoses--which contain type B2 and C lesions--in the study group than in the control group. The study group had significantly fewer calcified stenoses and complex morphology stenoses--the latter of which include lesion morphologies with chronic total occlusion, diffuse and calcification--than the control group.

CONCLUSIONS

For the high probability of CAD lesions that requires interventional therapy, patients with negative myocardial scintigraphy but typical angina symptoms would be beneficial to intensive medical treatment and coronary study.

Scrutiny of cardiovascular risk factors by assessing arterial stiffness in erectile dysfunction patients

PURPOSE

Erectile dysfunction (ED) is an early sign of vascular dysfunction. Studies have reported a correlation between arterial stiffness and cardiovascular events. The objective of this study was to evaluate the association among different criteria for assessing arterial stiffness and cardiovascular risk factors in ED patients.

METHODS

Assessment of pulse wave velocity (PWV), pulse pressure (PP), ratio of mitral inflow velocity to early diastolic velocity in the annulus derived by tissue Doppler imaging (E/Et), and intima-medial thickness (IMT) were performed in 200 ED patients.

RESULTS

Linear statistical analysis of the coronary artery disease risk factors revealed that PWV, PP and E/Et were positively correlated with age, duration of diabetes mellitus (DM), and systolic and diastolic blood pressures. PWV and E/Et were positively correlated with waist circumference and number of metabolic syndrome (MS) components. For category-wise analysis, the PWV, PP and E/Et were higher in patients with DM, hypertension and MS. Multiple regression analysis showed that the independent determinants for PWV comprised age, DM, hypertension, and MS; for PP comprised age, hypertension, and MS; for E/Et comprised age and MS; and for IMT comprised only DM.

CONCLUSIONS

Thus, PWV, PP and E/Et may be employed as markers to identify ED patients with potential cardiovascular risk factors, including MS and obesity.

Role of ankle-brachial pressure index as a predictor of coronary artery disease severity in patients with diabetes mellitus

BACKGROUND

Previous studies have reported a close correlation between low ankle-brachial pressure index (ABPI) and various cardiovascular risk factors. However, despite the well-established potential hazards of consequent coronary artery disease (CAD), no data exist on the relationship between ABPI and the severity of CAD, particularly in patients with diabetes mellitus (DM).

METHODS

A total of 840 patients ranging from 35 to 87 years of age (mean [+/- SD] 63.9+/-10.2 years) with suspected CAD in a clinical practice were enrolled. All patients underwent ABPI measurements and coronary angiography. Patients were divided into four groups according to the results of ABPI measurements and the presence or absence of DM: group A had an ABPI value of at least 0.9 but no DM (A-/D-); group B had an ABPI value of at least 0.9 and DM (A-/D+); group C had an ABPI of less than 0.9 but no DM (A+/D-); and group D had an ABPI value of less than 0.9 and DM (A+/D+).

RESULTS

Age was significantly higher in the A+ (groups C and D) than the A- patients (groups A and B). Moreover, men predominated in all four groups. Comparisons of sex distribution among the four groups revealed that group D had the highest percentage of women, while group A had the lowest. Total cholesterol level did not differ among the four groups, although group D tended to have the highest result. Patients in group D had the highest percentages of hypertension, hypercholesterol, hypertriglyceride, low high-density lipoprotein cholesterol and high low-density lipoprotein cholesterol among the four groups. Group D exhibited the highest triglyceride and uric acid levels, the lowest high-density lipoprotein cholesterol level, and the highest metabolic syndrome criteria number and percentage of metabolic syndrome. Furthermore, group D had the highest mean lesion numbers, mean numbers of target vessel involvement, stenoses with type C classification and complex morphology lesions (chronic total occlusion, diffuse or calcified lesions) among the four groups. There were still significant differences in lesion numbers (P<0.001) and numbers of target vessel involvement (P<0.001) for ABPI predicting CAD severity after controlling for the effects of DM and age. The sensitivity, specificity, positive predictive value and negative predictive value of using an ABPI of less than 0.9 to predict CAD differed significantly between patients with and without DM.

CONCLUSIONS

ABPI is a useful noninvasive tool for predicting CAD severity, even in patients with DM.

Ankle-arm index is a useful test for clinical practice in outpatients with suspected coronary artery disease

BACKGROUND

Although a low ankle-arm index (AAI) has been reported to be associated with increased risk of cardiovascular mortality in several populations, no data exist concerning the impact of AAI for outpatients with suspected coronary artery disease (CAD) in the clinical setting.

METHODS AND RESULTS

The present study enrolled 840 outpatients (age range 35-87 years, mean age 63.9+/-10.2) with suspected CAD. All patients underwent AAI measurements and coronary angiography, and based on the AAI values, they were divided into group A (AAI <0.9; n=191; CAD positive, 181) and group B (AAI >or=0.9; n=649; CAD positive, 509). Metabolic syndrome (MS), obesity, and level of the inflammatory biomarker high sensitive C-reactive protein (hsCRP) were compared between the 2 groups. The sensitivity, specificity, positive and negative predictive values in predicting CAD with an AAI value <0.9 in all patients were 26.2%, 93.3%, 94.8% and 21.6%, respectively. The patients in group A was significantly older and there was a higher female-to-male ratio than in group B. The presence of hypertension and diabetes mellitus, current smoking status, and levels of low density lipoprotein (LDL)-cholesterol level, uric acid and hsCRP differed significantly between the 2 groups. Group A had a higher percentage of high LDL-cholesterol level, high waist-to-hip ratio and more positive cases of MS than group B. Multivariate logistical regression analysis showed that AAI was related to MS, high levels of hsCRP (>3 mg/L) and uric acid (>7 mg/dl) with odds ratios of 1.769, 3.907 and 2.580, respectively.

CONCLUSIONS

The AAI test is an effective tool in predicting CAD in outpatients in clinical practise.

Ankle-arm index as a predictor of lesion morphology and risk classification for coronary artery disease undergoing angioplasty

BACKGROUND

Low ankle-arm systolic blood pressure index is strongly correlated with various cardiovascular risk factors. However, although the potential hazards of resulting coronary artery disease (CAD) are well established, no data is available regarding how ankle-arm index (AAI) and CAD severity are related.

METHODS

This study enrolled 477 patients and all patients underwent coronary angiography and AAI measurements. Based on AAI values, patients were divided into study (AAI value of <0.9, 126 patients) and control groups (AAI value of >or=0.9, 351 patients).

RESULTS

Among baseline characteristics, the study group showed a significantly older and higher female ratio than the control group. The presence of hypertension, diabetes mellitus (DM), current smoking status and LDL-cholesterol level differed significantly between these two groups. Mean number of lesions and target vessel involvement were significant different between the study and control group (2.6+/-1.1 vs. 1.9+/-1.0, p<0.0001; 2.0+/-0.8 vs. 1.6+/-0.7, p<0.0001). Percentages of lesion sites on ostial and proximal portions were markedly high in the study group than in the control group. Significant differences also emerged in the complex stenotic lesions (B2 or C) and lesion morphology (calcified, chronic total occlusion, irregular, bifurcation and diffuse) of these two groups. Multivariate logistic regression analysis, showed that AAI is a statistically significant independent predictor for lesion site, complex stenotic lesions and lesion morphology with Odds ratios (ORs) of, respectively, 1.728, 2.880 and 2.71.

CONCLUSIONS

The AAI is a useful non-invasive tool for the prediction of CAD severity.