Clinical presentation and management of stable coronary artery disease: insights from the international prospective CLARIFY registry - results from the Greek national cohort

INTRODUCTION

Coronary artery disease (CAD) is highly prevalent worldwide, yet there is a paucity of data regarding the clinical characteristics and management of outpatients with stable CAD. In this paper, we report the baseline data of the Greek cohort and we compare our national data with the global results of the entire registry, as well as the results from the western European countries.

METHODS

CLARIFY is an international, prospective, observational, longitudinal registry of outpatients with stable CAD, defined as prior myocardial infarction or revascularization procedure, evidence of coronary stenosis >50%, or chest pain associated with proven myocardial ischemia. A total of 33,283 patients from 45 countries in 4 continents were enrolled between November 2009 and July 2010; of these, 14,726 were from western European countries (Austria, Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Netherlands, Portugal, Spain, Switzerland and the United Kingdom) and 559 patients were enrolled in Greece.

RESULTS

Compared to their counterparts in western Europe and the entire cohort, Greeks were younger (p<0.0001, p<0.0001, respectively), more predominantly male (p<0.0039, p<0.0001), with a higher body mass index (p<0.0002, p<0.0001) and a larger waist circumference (p<0.0001, p<0.0001), as well as a higher prevalence of family history of CAD (p<0.0008, 0.0005), hyperlipidemia (p<0.0001, p<0.0001) and smoking (p<0.0001, p<0.0001). Noninvasive testing (p<0.0001, p<0.0001, respectively) and coronary angiography (p<0.0001, 0.0013) along with surgical revascularization (CABG) (p<0.0001, 0.0088) were performed more often in Greece. Antiplatelets, b-blockers and lipid lowering medications were used to an equal extent in Greece as in the other two cohorts.

CONCLUSION

There are substantial differences in demographics, clinical profiles and treatment in patients with stable CAD within the data set, which are also observed for Greek data. Interestingly, these differences are consistent in relation to the global as well as the western European data.

Increased mobilization of mesenchymal stem cells in patients with essential hypertension: the effect of left ventricular hypertrophy

Stem cells have great clinical significance in many cardiovascular diseases. However, there are limited data regarding the involvement of mesenchymal stem cells (MSCs) in the pathophysiology of arterial hypertension. The aim of this study was to investigate the circulation of MSCs in patients with essential hypertension. The authors included 24 patients with untreated essential hypertension and 19 healthy individuals. Using flow cytometry, MSCs in peripheral blood, as a population of CD45-/CD34-/CD90+ cells and also as a population of CD45-/CD34-/CD105+ cells, were measured. The resulting counts were translated into the percentage of MSCs in the total cells. Hypertensive patients were shown to have increased circulating CD45-/CD34-/CD90+ compared with controls (0.0069%±0.012% compared with 0.00085%±0.0015%, respectively; P=.039). No significant difference in circulating CD45-/CD34-/CD105+ cells was found between hypertensive patients' and normotensive patients' peripheral blood (0.018%±0.013% compared with 0.015%±0.014%, respectively; P=.53). Notably, CD45-/CD34-/CD90+ circulating cells were positively correlated with left ventricular mass index (LVMI) (r=0.516, P<.001). Patients with essential hypertension have increased circulating MSCs compared with normotensive patients, and the number of MSCs is correlated with LVMI. These findings contribute to the understanding of the pathophysiology of hypertension and might suggest a future therapeutic target.

Sinus rhythm restoration affects collagen turnover in patients with persistent atrial fibrillation

AIMS

Collagen turnover and atrial fibrosis have been implicated in the generation and perpetuation of atrial fibrillation (AF). We evaluated the importance of serum markers of collagen turnover in predicting the outcome of electrical cardioversion (CV) of persistent AF and the relationship between AF and fibrosis.

METHODS AND RESULTS

Serum C-terminal pro-peptide of collagen type-I (CICP) and C-terminal telopeptide of collagen type-I (CITP) were measured in 164 patients with AF before and 2 months after CV. All the patients were successfully cardioverted to sinus rhythm (SR) although in 38 of them AF recurred. Baseline CICP levels were comparable in patients in SR 60 days after CV and in those who experienced a relapse of AF (85.08 ± 16.99 vs. 87.55 ± 10.43 ng/mL, respectively, P = ns). Baseline CITP levels were significantly higher in patients with AF recurrence compared with those who remained in SR (0.48 ± 0.16 vs. 0.32 ± 0.17 ng/mL, respectively, P < 0.0001). In the 126 patients who maintained the SR, CICP levels were significantly lower at the end of the study as compared with the baseline (63.74 ± 15.92 vs. 85.08 ± 16.99 ng/mL P = 0.003), while there was a mild increase in plasma CITP levels (0.36 ± 0.21 vs. 0.32 ± 0.17 ng/mL, respectively, P = 0.03).

CONCLUSION

Atrial fibrillation can result in alterations in atrial structure and architecture that make the atrial myocardium more susceptible to the maintenance of the arrhythmia. Sinus rhythm restoration could affect the fibrotic process occurring or exacerbating during AF course.

Biochemical characterisation of Troponin C mutations causing hypertrophic and dilated cardiomyopathies

Cardiac muscle contraction occurs through an interaction of the myosin head with the actin filaments, a process which is regulated by the troponin complex together with tropomyosin and is Ca(2+) dependent. Mutations in genes encoding sarcomeric proteins are a common cause of familial hypertrophic and dilated cardiomyopathies. The scope of this review is to gather information from studies regarding the in vitro characterisation of six HCM and six DCM mutations on the cardiac TnC gene and to suggest, if possible, how they may lead to dysfunction. Since TnC is the subunit responsible for Ca(2+) binding, mutations in the TnC could possibly have a strong impact on Ca(2+) binding affinities. Furthermore, the interactions of mutant TnCs with their binding partners could be altered. From the characterisation studies available to date, we can conclude that the HCM mutations on TnC increase significantly the Ca(2+) sensitivity of force development or of ATPase activity, producing large pCa shifts in comparison to WT TnC. In contrast, the DCM mutations on TnC have a tendency to decrease the Ca(2+) sensitivity of force development or of ATPase activity in comparison to WT TnC. Furthermore, the DCM mutants of TnC are not responsive to the TnI phosphorylation signal resulting in filaments that preserve their Ca(2+) sensitivity in contrast to WT filaments that experience a decrease in Ca(2+) sensitivity upon TnI phosphorylation.

MicroRNA-9 and microRNA-126 expression levels in patients with essential hypertension: potential markers of target-organ damage

MicroRNAs (miRs), as essential gene expression regulators, modulate cardiovascular development and disease and thus they are emerging as potential biomarkers and therapeutic targets in cardiovascular disease, including hypertension. We assessed the expression levels of the microRNAs miR-9 and miR-126 in 60 patients with untreated essential hypertension and 29 healthy individuals. All patients underwent two-dimensional echocardiography and 24-hour ambulatory blood pressure monitoring. MicroRNA expression levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed significantly lower miR-9 (9.69 ± 1.56 vs 41.08 ± 6.06; P < .001) and miR-126 (3.88 ± 0.47 vs 8.96 ± 1.69; P < .001) expression levels compared with healthy controls. In hypertensive patients, miR-9 expression levels showed a significant positive correlation (r = 0.437; P < .001) with left ventricular mass index. Furthermore, both miR-9 (r = 0.312; P = .015) and miR-126 (r = 0.441; P < .001) expression levels in hypertensive patients showed significant positive correlations with the 24-hour mean pulse pressure. Our data reveal that miR-9 and miR-126 are closely related to essential hypertension in humans, as they show a distinct expression profile in hypertensive patients relative to healthy individuals, and they are associated with clinical prognostic indices of hypertensive target-organ damage in hypertensive patients. Thus, they may possibly represent potential biomarkers and candidate therapeutic targets in essential hypertension.

Circulating endothelial progenitor cells in hypertensive patients with increased arterial stiffness

The potential association between arterial stiffening and circulating endothelial progenitor cells (EPCs) in patients with essential hypertension was investigated. Pulse wave velocity (PWV) was used to evaluate arterial stiffness in 24 patients with essential hypertension and 19 healthy controls. Blood samples were taken and immunostained with antibodies against the cell surface markers CD34, CD45, and CD133. Using flow cytometry, EPCs as a population of CD45-/CD34+/CD133+ cells were measured. Hypertensive patients were not found to have higher levels of circulating CD45-/CD34+/CD133+ compared with the control group (0.0026%±0.0031% vs 0.0023%±0.0023%, respectively; P=.7). Correlation analysis revealed a strong association between the number of CD45-/CD34+/CD133+ cells and PWV (r=0.58, P<.001), indicating that hypertensive patients with increased PWV have a greater percentage of CD45-/CD34+/CD133+ cells. Data showed a correlation between the number of circulating CD45-/CD34+/CD133+ cells and arterial stiffness, suggesting that those cells might have a role in arterial remodeling.

Early cardiac gene transcript levels in peripheral blood mononuclear cells reflect severity in stable coronary artery disease

INTRODUCTION

The early cardiac marker genes myocardin, GATA4 and Nkx2.5, play a role in both embryonic cardiovascular development and adult cardiovascular disease. We evaluated transcript levels of myocardin, GATA4 and Nkx2.5 in peripheral blood mononuclear cells (PBMCs) in patients with stable coronary artery disease (CAD) and we examined the relationship between these levels and the severity of the disease, estimated by the number of stenotic vessels involved.

METHODS

Ninety-eight patients with stable CAD (age 66 ± 9 years) who underwent coronary angiography participated in the study; 66 healthy individuals (age 58 ± 13 years) were also included for comparison. Gene transcript levels were determined by quantitative real-time reverse transcription polymerase chain reaction.

RESULTS

Patients with 3-vessel CAD had elevated transcript levels of myocardin (median difference 2.7, p=0.001, 95% confidence interval, CI: 1-5.8), GATA4 (median difference 0.3, p=0.015, 95% CI: 0.1-1.9) and Nkx2.5 (median difference 16.1, p<0.001, 95% CI: 4.5-23) compared to healthy controls. Patients with 3-vessel CAD also showed elevated transcript levels of myocardin (median difference 2.3, p=0.001, 95% CI: 0.49-5.5) and Nkx2.5 (median difference 11.8, p<0.001, 95% CI: 1.5-21.5) compared to patients with 1-vessel CAD.

CONCLUSIONS

Early cardiac marker gene transcript levels are significantly higher in the PBMCs of patients with severe stable CAD than in those of healthy controls, and show alterations in their expression profile according to the disease severity status. Our results indicate for the first time that changes in the early cardiac gene expression in the peripheral blood of stable CAD patients, possibly as a result of alterations in circulating cardiovascular progenitor cells that express these genes, may reflect the level of disease severity.

Differential gene expression of bradykinin receptors 1 and 2 in peripheral monocytes from patients with essential hypertension

Bradykinin participates in various hypertensive processes, exerted via its type 1 and type 2 receptors (BKR1 and BKR2). The aim of the study was to investigate BKR1 and BK2R gene expression in peripheral monocytes in patients with essential hypertension compared with healthy individuals. Seventeen hypertensive patients (9 males, age 56 ± 7 years) and 12 healthy individuals (7 males, age 55 ± 6) participated. Mononuclear cells isolated using anti-CD14+ antibodies and mRNAs of BKR1 and BKR2 were estimated by real-time quantitative reverse transcription-PCR. Both BKR1 and BKR2 showed significantly upregulated gene expression in the group of hypertensive patients. Specifically, BKR1 gene expression was 142.1 ± 42.2 in hypertensives versus 20.2 ± 8 in controls (P = 0.024) and BKR2 was 1222.2 ± 361.6 in hypertensives versus 259.5 ± 99.1 in controls (P = 0.038). Antihypertensive treatment resulted in a decrease in BKR1 (from 142.1 ± 42.2 to 55.2 ± 17.1, P = 0.065) and in BKR2 (from 1222.2 ± 361.6 to 256.8 ± 81.8, P = 0.014) gene expression. BKR1 and BKR2 gene expression on peripheral monocytes is upregulated in essential hypertension. This may lead to functional changes in monocytes and contribute to the development of target organ damage in hypertensive patients.

Differential expression of vascular smooth muscle-modulating microRNAs in human peripheral blood mononuclear cells: novel targets in essential hypertension

Vascular smooth muscle cell (VSMC) phenotypic plasticity has a critical role in the pathophysiology of arterial remodeling in essential hypertension. MicroRNAs are emerging as potential biomarkers and therapeutic targets in cardiovascular disease. We assessed the expression levels of the microRNAs miR-143, miR-145, miR-21, miR-133 and miR-1, which are implicated in VSMC phenotypic modulation, in 60 patients with essential hypertension and 29 healthy individuals. All patients underwent 24-h ambulatory blood pressure (BP) monitoring. MicroRNA levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed lower miR-143 (2.20±0.25 versus 4.19±0.57, P<0.001), miR-145 (13.51±1.73 versus 22.38±3.31, P=0.010) and miR-133 (8.15±1.32 versus 37.03±8.18, P<0.001) and higher miR-21 (3.08±0.32 versus 2.06±0.31, P=0.048) and miR-1 (33.94±5.19 versus 12.35±2.13 P=0.006) expression levels compared with controls. In hypertensive patients, we observed correlations of miR-143 (r = -0.380, P=0.003), miR-145 (r=-0.405, P=0.001), miR-21 (r=-0.486, P<0.001) and miR-133 (r=0.479, P<0.001) expression levels with 24-h diastolic BP. Furthermore, we observed correlations of miR-21 (r=-0.291, P=0.024), miR-1 (r=-0.312, P=0.015) and miR-133 (r=0.310, P=0.016) levels with the dipping status. Associations of miR-143 (r=-0.292, P=0.025), miR-145 (r=-0.399, P=0.002), miR-21 (r=-0.343, P=0.008) and miR-133 (r=0.370, P=0.004) levels with 24-h mean pulse pressure were also found. Our data provide important evidence that VSMC-modulating microRNAs are closely related to essential hypertension in humans and they may represent potential therapeutic targets in essential hypertension.