Lipoprotein-associated phospholipase A2 levels, endothelial dysfunction and arterial stiffness in patients with stable coronary artery disease.

BACKGROUND: Lipoprotein-associated Phospholipase A2 (Lp-PLA2), can exert proinflammatory as well as proatherogenic properties on the vascular wall. The current study sought to evaluate the influence of high Lp-PLA2 levels on indices of arterial wall properties in patients with stable coronary artery disease (CAD). METHODS: Three hundred seventy-four consecutive patients with stable CAD (mean age 61 ± 11 years, 89% males) were enrolled in this single-center cross-sectional study. Flow-mediated dilation (FMD) was used to assess endothelial function and augmentation index (AIx) of the central aortic pressure was used to assess reflected waves. ELISA was used to determine Lp-PLA2 serum levels. RESULTS: After dividing the participants in 3 equal groups based on the tertiles of circulating Lp-PLA2 values, no significant differences were demonstrated between those in the 3rd tertile with Lp-PLA2 values > 138 µg/L, in the 2nd tertile with Lp-PLA2 values between 101 and 138 µg/L and in the 1st tertile (Lp-PLA2 values < 101 µg/L) regarding age, male gender, smoking habits, family history of CAD or history of a previous myocardial infarction, diabetes mellitus, arterial hypertension, hyperlipidemia, duration of CAD and treatment with relevant medication. Importantly, subjects with Lp-PLA2 values in the highest tertile, had significantly reduced FMD values compared to the middle and lower tertile (4.43 ± 2.37% vs. 4.61 ± 1.97% vs. 5.20 ± 2.52% respectively, P = 0.03). Patients in the highest tertile of Lp-PLA2 values had significantly higher AIx values (24.65 ± 8.69% vs. 23.33 ± 9.65%, P = 0.03), in comparison to the lowest tertile, with Lp-PLA2 values < 101 µg/L. A linear regression analysis showed that Lp-PLA2 values > 138 µg/L negatively correlated to FMD [b = - 0.45 (95% CI: - 0.79 - -0.11), P = 0.01] and AIx values [b = 1.81 (95% CI: 0.57-3.05), P < 0.001] independently of cofounders like gender, age, diabetes mellitus, arterial hypertension, dyslipidemia, smoking habits, family history of CAD, history of previous myocardial infarction, serum glucose, circulating lipid levels, duration of CAD, antihypertensive medication, antidiabetic drugs, statin therapy and treatment with ß-blockers. CONCLUSIONS: Elevated Lp-PLA2 levels relate to endothelial dysfunction and arterial stiffness in patients with stable CAD independently from classical risk factors for CAD, statin use, antihypertensive treatment, and duration of the disease.

Acute Coronary Syndrome with Non-ruptured Plaques (NONRUPLA): Novel Ideas and Perspectives.

PURPOSE OF REVIEW: In this review article, we focus on the mechanisms and features of acute coronary syndromes (ACS) with no ruptured plaque (NONRUPLA) highlighting the uncertainties over diagnostic evaluation and treatment. RECENT FINDINGS: The most common cause of ACS is obstruction due to atherosclerotic plaque ruptured or erosion. In 14% of patients who present in the Emergency Department as myocardial infarction, the final diagnosis is ACS with NONRUPLA. Although the clinical presentation of NONRUPLA may mimic myocardial infarction, the underlying pathogenesis is different, and it may guide therapeutic approaches and overall prognosis that vary according to etiology. The possible mechanisms of ACS with NONRUPLA are coronary embolism, acute dissection of the aorta or coronary artery, vasospasm, microvascular dysfunction, the imbalance between oxygen demand and supply, coronary trauma and stent complications, direct cellular toxicity and damage, Takotsubo syndrome, and myocardial infarction with non-obstructive coronary arteries (MINOCA).

Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance.

Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.

Prognostic significance of arterial stiffness and osteoprotegerin in patients with stable coronary artery disease.

BACKGROUND: Arterial stiffness and vascular calcification significantly contribute to coronary atherosclerosis progression. The prognostic value of increased arterial stiffness and vascular calcification in subjects with stable coronary artery disease (CAD) after percutaneous coronary intervention(PCI) is currently under question. MATERIALS AND METHODS: We randomly enrolled 262 patients with stable CAD 1 month after successful PCI. Carotid-femoral pulse wave velocity (PWV) was measured as a well-established index of central aortic stiffness. Osteoprotegerin (OPG) plasma levels were measured as a biomarker of vascular calcification. Patients were followed up prospectively up to 52 months. The primary endpoint was the composite of death from cardiovascular causes, myocardial infarction, stroke or hospitalization for cardiovascular causes. RESULTS: During the follow-up period, 48 patients presented the primary composite endpoint. Subjects who presented the primary endpoint, compared to subjects free of cardiovascular events, had significantly increased PWV (9.45 ± 2.19 m/s vs 8.73 ± 2.07 m/s, P = .04) and OPG levels (4.21 ± 2.19 pmol/L vs 3.18 ± 1.74 pmol/L, P = .003). Survival analysis indicated that PWV predicted adverse cardiac events MACE (Hazard ratio = 1.29 95%CI: 1.07-1.57, P = .008) independently from confounders such as age, sex, smoking habits, ejection fraction, extent of coronary artery disease, hypertension and diabetes mellitus. Interestingly, for every increase in pulse wave velocity by 1 m/s, there is an anticipated increase in the risk of major adverse cardiovascular event (MACE) by 29%. CONCLUSIONS: These findings extend the current knowledge concerning the role of arterial stiffness as powerful biomarkers in cardiovascular disease. Measurement of PWV might have a role in ascertaining prognosis and managing treatment in patients with stable CAD after PCI.

Different Prognostic Significance of Cardiac Troponin at Presentation and Peak Cardiac Troponin in Patients with Non-ST Segment Elevation Myocardial Infarction.

OBJECTIVES: Non-ST elevation myocardial infarction (NSTEMI) is one of the most common manifestations of acute coronary syndromes (ACS). We evaluated the prognostic role of cardiac troponin I (cTnI) at presentation and peak cardiac troponin I in patients with NSTEMI. METHODS: We consecutively enrolled 215 subjects presenting with NSTEMI. Subjects were followed up for 1 year. cTnI at presentation and the peak value of cTnI were measured. The primary end point was defined as cardiovascular death, readmission to hospital with heart failure and new ACS. RESULTS: The subjects who presented the primary end point (49 subjects) had significantly increased values of peak cTnI compared to subjects free of cardiovascular events [7.19 (2.97-21.32) vs. 4.09 (1.18-11.85) ng/l; p = 0.002]. Nevertheless, cTnI at presentation did not differ between subjects who presented the primary end point and those free of events (p = 0.39). Multivariate Cox regression analysis after adjustment for confounders revealed by the univariate analysis showed that for an increase in peak cTnI from 1 to 10 ng/l, there is a 60% anticipated increase in the relative risk to present the primary end point (p = 0.04). CONCLUSION: These findings documented the different prognostic significance of cTnI at presentation and peak cTnI in patients presenting with NSTEMI, and highlighted the importance of monitoring the levels of cTnI in this high-risk population.

Expression of Tissue microRNAs in Ascending Aortic Aneurysms and Dissections.

Little is known about the role of serum and tissue mediators in the progression of ascending aortic aneurysms and dissections. We examined how the tissue expression of microRNAs and matrix metalloproteinases (MMPs), as well as the serum levels of osteoprotegerin, adiponectin, and high sensitivity C-reactive protein (hsCRP) are associated with these entities. We enrolled 21 patients with ascending aortic aneurysm, 11 with acute Stanford type A aortic dissection and 18 controls. The serum levels of osteoprotegerin, adiponectin, and hsCRP, as well as the tissue expression of MMPs 2 and 9 and tissue microRNAs 29 and 195 were compared among groups. There was no difference regarding serum osteoprotegerin, adiponectin, and tissue MMP2 and MMP9 levels. hsCRP was higher in the dissection group (P = .03). Tissue expression of microRNA 29 was 2.11-fold higher in the dissection (P = .001) and 2.99-fold higher in the aneurysm group (P < .001), compared with the control group. Tissue expression of microRNA 195 was 2.72-fold higher in the dissection (P < .001) and 2.00-fold lower in the aneurysm group (P = .08), compared with to the control group. These findings support the contribution of microRNAs in the progression of aneurysm formation and dissection, suggesting a role as potential biomarkers and future therapeutic targets.

Induction of vascular GTP-cyclohydrolase I and endogenous tetrahydrobiopterin synthesis protect against inflammation-induced endothelial dysfunction in human atherosclerosis.

BACKGROUND: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) is essential for maintenance of enzymatic function. We hypothesized that induction of BH4 synthesis might be an endothelial defense mechanism against inflammation in vascular disease states. METHODS AND RESULTS: In Study 1, 20 healthy individuals were randomized to receive Salmonella typhi vaccine (a model of acute inflammation) or placebo in a double-blind study. Vaccination increased circulating BH4 and interleukin 6 and induced endothelial dysfunction (as evaluated by brachial artery flow-mediated dilation) after 8 hours. In Study 2, a functional haplotype (X haplotype) in the GCH1 gene, encoding GTP-cyclohydrolase I, the rate-limiting enzyme in biopterin biosynthesis, was associated with endothelial dysfunction in the presence of high-sensitivity C-reactive protein in 440 coronary artery disease patients. In Study 3, 10 patients with coronary artery disease homozygotes for the GCH1 X haplotype (XX) and 40 without the haplotype (OO) underwent S Typhi vaccination. XX patients were unable to increase plasma BH4 and had a greater reduction of flow-mediated dilation than OO patients. In Study 4, vessel segments from 19 patients undergoing coronary bypass surgery were incubated with or without cytokines (interleukin-6/tumor necrosis factor-α/lipopolysaccharide) for 24 hours. Cytokine stimulation upregulated GCH1 expression, increased vascular BH4, and improved vasorelaxation in response to acetylcholine, which was inhibited by the GTP-cyclohydrolase inhibitor 2,4-diamino-6-hydroxypyrimidine. CONCLUSIONS: The ability to increase vascular GCH1 expression and BH4 synthesis in response to inflammation preserves endothelial function in inflammatory states. These novel findings identify BH4 as a vascular defense mechanism against inflammation-induced endothelial dysfunction.

Coronary versus carotid artery plaques. Similarities and differences regarding biomarkers morphology and prognosis.

Carotid and coronary artery disease are two major atherosclerotic conditions that have shown an increased prevalence in the last three decades that is associated with high morbidity and mortality. Recent data have revealed that the development of the atherosclerotic plaque-the basic entity in both diseases-may share similar characteristics and mechanisms irrespective of the location site. Even though the biology of atherosclerotic process is similar, there are differences in plaque morphology and characteristics. Indeed, plaque erosion, calcified nodules, fibrous cap thickness and macrophage accumulation may be different in the setting of coronary and carotid artery disease. The perivascular adipose tissue surrounding the coronary arteries (but not carotids) could also affect plaque biology. In this review we focus on comparative the characteristics of both types of atherosclerotic plaques and summarize existing knowledge to provide useful conclusions about current and future treatment strategies.

Antiplatelet Therapy in Acute Coronary Syndromes. Evidence Based Medicine.

BACKGROUND: Acute coronary syndromes (ACS) represent the final step in the chronic process of atherothrombotic coronary disease which begins early in life as thickening of intima layer and progresses to fibroatheroma and fibrocalcific lesions with vulnerable characteristics. METHODS: As abrupt occlusion in the settings of ACS happens due to platelet aggregation and mobilization antiplatelet treatment has gained significant interest especially in the settings of primary percutaneous intervention and the aim of this review article is to understand the current evidence justifying the use and combination of different antiplatelet agents. RESULTS: Beyond aspirin, several antiplatelet agents (ADP receptor inhibitors, Glycoprotein IIb/IIIa inhibitors and varopaxar) are used in combination to effectively inhibit platelet activity. However the best choice, initiation, combination and duration of antithrombotic treatment, in order to maximize the effectiveness of therapy and reduce the hazard of bleeding, depends on the clinical setting and patient specific characteristics and is an issue of intense scientific interest. CONCLUSION: Early and potent platelet inhibition with safety reassurance can be achieved by a combination of antiplatelet agents and is essential for the management of ACS. Therefore in this review article we focus on the current evidence regarding rational, safety and effectiveness of current antiplatelet approaches in acute coronary syndromes.

Effects of CYP2C19 Polymorphism on Endothelial Function, Arterial Stiffness and Inflammation in Coronary Artery Disease Patients Under Clopidogrel Treatment.

BACKGROUND: Clopidogrel's ability to inhibit platelet function determined its clinical usefulness. The role of CYP2C19*2 genotype on antiplatelet treatment is recently under question. Arterial wall properties and inflammation are key players in atherosclerosis development. Hence, we evaluated the impact of CYP2C19*2 genetic polymorphism on endothelial function, arterial stiffness and inflammation in coronary artery disease (CAD) patients receiving clopidogrel treatment. METHODS AND RESULTS: In this study we enrolled 408 consecutive patients with stable CAD under dual antiplatelet therapy (clopidogrel 75mg/day, aspirin 100mg/day), 30 days after percutaneous coronary intervention. Measurement of flow-mediated dilation (FMD) of the brachial artery was used to evaluate endothelial function. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) was measured to estimate arterial stiffness. Real time polymerase chain reaction was used for the genotyping of CYP2C19*2. Levels of tumor necrosis factor alpha (TNF-a) and interleukin 6 (IL-6) were measured with ELISA. We found no difference in basic clinical and demographic characteristics nor in FMD, PWV, AIx and inflammatory status (p=NS for all) between CYP2C19 homozygotes for the wild type; carriers of reduced function allele and homozygotes for the reduced function allele. CONCLUSION: CYP2C19*2 loss of action polymorphism causes no impact on vascular function and inflammatory status in stable CAD patients receiving clopidogrel treatment.

Role of depression in heart failure--choosing the right antidepressive treatment.

Major depression is a common feature of heart failure patients and possibly stems from their common biochemical background. Depression and heart failure co-morbidity has several clinical implications on the prognosis of these patients. Furthermore antidepressive drugs have known cardiovascular side effects, while their safety and efficacy in heart failure has not been fully elucidated yet. The right choice of antidepressive treatment in heart failure constitutes an issue of high importance as it can affect the clinical outcome of these patients. In this article we highlight the role of major depression in heart failure and demonstrate their common biochemical background. Moreover we review the acquired so far knowledge on the use of the various categories of antidepressants in heart failure by reference to the existing clinical studies on antidepressants efficacy and safety in heart failure. Even though certain conclusions cannot be drawn yet, evidence suggests that the use of selective serotonin reuptake inhibitors may have a beneficial effect on clinical outcome of heart failure patients.

Novel therapeutic strategies targeting vascular redox in human atherosclerosis.

It is now widely accepted that redox signaling is a key feature in vascular homeostasis. Reactive oxygen species are generated by a wide range of enzymatic systems located in both vascular endothelium and vascular wall. Further, to their role as cytotoxic molecules produced by immune system, free radicals play critical signaling roles in the vascular wall. By regulating several redox-sensitive transcription pathways, free radicals play a key role in the synthesis of inflammatory mediators in both vascular endothelium and vascular wall, with important role in the overall vascular dysfunction. The well-established role of redox state in vascular disease mandates that development of newer therapeutic strategies should be able to alter redox-sensitive intracellular signaling events. Widely used cardiovascular agents like statins or angiotensin receptor blockers have well documented beneficial effects on vascular redox state, reflected also in clinical outcome improvement. Newer promising strategies along with recent patented inventions may also include thiazolidinediones, folates, tetrahydrobiopterin, cyclopentone prostaglandins and aldose reductase inhibitors with well known effects on vascular redox, but with still unclear results on clinical outcome. Better understanding of redox-sensitive intracellular signaling pathways could indicate the critical steps to intervene with newer agents to reverse vascular dysfunction, inhibiting atherosclerosis progression and potentially improve clinical outcome.