Gianluca Petrillo

Neopterin: From Forgotten Biomarker to Leading Actor in Cardiovascular Pathophysiology

Inflammation plays a role at all stages of atherosclerosis. Neopterin, a pteridine mainly synthesized by activated macrophages, is a marker of inflammation, immune system activation and an active participant in cardiovascular disease. Measurement of neopterin levels may help follow the evolution of specific inflammatory conditions (e.g. viral infection, renal transplant rejection, systemic inflammatory diseases, nephritic syndrome and autoimmune diseases). Serum levels of neopterin are elevated also in patients with coronary artery disease (CAD) and peripheral artery disease (PAD). Moreover, plasma levels of this molecule might predict adverse cardiovascular events in patients with CAD, acute coronary syndromes or severe PAD. In addition, neopterin levels are related to the development of heart failure. We provide an updated overview on neopterin and, its links with CAD, left ventricular dysfunction, and PAD. We also describe its potential role in cardiac regenerative strategies with using bone marrow cells.

Increased High Mobility Group Box-1 Protein Levels are Associated With Impaired Cardiopulmonary and Echocardiographic Findings After Acute Myocardial Infarction

BACKGROUND Several markers of systemic inflammation seem to play an active role in the pathophysiology of acute coronary syndrome and its evolution. High mobility group box-1 (HMGB-1), a ubiquitous nuclear protein constitutively expressed in quiescent cells, was recently recognized as a newer critical mediator of inflammatory diseases. The present study aimed to evaluate the possible association between HMGB-1 levels and structural and functional indices of cardiovascular performance such as cardiopulmonary and Doppler-echocardiography indices in patients after acute myocardial infarction (MI). METHODS AND RESULTS Fifty-four consecutive patients (mean age 58.3 years, 83% males) recovering from acute MI were included in the study protocol. All patients underwent Doppler-echocardiography, cardiopulmonary exercise, and HMGB-1 assay. HMGB-1 levels in acute MI patients were significantly higher compared with age- and body mass index-matched controls (14.8 +/- 6.8 vs. 2.3 +/- 1.0 ng/mL, P < .0001, respectively). Postinfarction patients showed oxygen consumption at peak exercise (VO(2 peak)) = 14.4 +/- 4.2 mL x kg x min and a slope of increase in ventilation over carbon dioxide output (VE/VCO(2 slope)) = 32.1 +/- 6.2, whereas Doppler-echocardiography values were: left ventricular end-diastolic volume (LVEDV) = 53.4 +/- 8.2 mL/m(2); left ventricular ejection fraction (LVEF) = 41.7 +/- 7.0%. Multiple linear regression analysis (stepwise method) showed that VO(2 peak) (beta = -0.276, P = .012), VE/VCO(2 slope) (beta = 0.244, P = .005), LVEDV (beta = 0.267, P = .018), peak creatine kinase-MB (beta = 0.339, P = .004), peak Troponin I (beta = 0.244, P = .002), and LVEF (beta = -0.312, P = .021) were significantly associated with HMGB-1 levels. CONCLUSIONS The present study demonstrated that in postinfarction patients, HMGB-1 levels were significantly higher compared with controls, and significantly correlated with cardiopulmonary and Doppler-echocardiography parameters.

Effects of exercise training on high-mobility group box-1 levels after acute myocardial infarction.

BACKGROUND High-mobility group box-1 (HMGB1) is a novel predictor of adverse postinfarction clinical outcomes, playing a crucial role in the appropriate postinfarction healing process. METHODS AND RESULTS Seventy-five postinfarction patients were enrolled in a single-center randomized study (clinicaltrial.gov identifier: NCT00755131). Group T patients (training, n = 37) underwent 6-month exercise-based cardiac rehabilitation (CR) program, whereas group C patients (controls, n = 38) were discharged with generic instructions for maintaining physical activity and a correct lifestyle. After 6 months, HMGB1 levels were significantly reduced in the total population (26.1 ± 23.5 vs. 16.2 ± 12.9 ng/mL; P = .0006). After adjusting for several confounders, linear regression analysis showed that the inclusion in the training group (β = -10.54, P = .043) was associated with marked reduction of HMGB1 levels. After 6 months, HMGB1 levels were significantly lower in trained patients compared to controls (11.7 ± 7.0 vs. 20.5 ± 15.6 ng/mL, P = .0027, respectively). In trained patients, decreased HMGB1 levels were significantly associated with the improvement in peak oxygen consumption (β = -3.879, P = .003) and heart rate recovery (β = -2.492, P = .002), and with reduced left ventricular end-diastolic volume (β = 1.412, P = .001) and wall motion score index (β = 1.138, P = .002). CONCLUSIONS The decrease in HMGB1 levels after anterior myocardial infarction was associated with exercise training and with the improvement of cardiopulmonary and autonomic function, and with favorable cardiac remodeling.

Pro-atherothrombotic effects of leptin in human coronary endothelial cells

Adipocytes are nowadays recognised as cells able to produce and secrete a large variety of active substances termed adipokines, which exert direct effects on vascular cells. Among these adipokines, leptin has been proposed to play a role in the pathophysiology of acute coronary syndromes, as well as in increasing cardiovascular risk. At the moment, however, the mechanisms linking leptin to cardiovascular disease are not completely understood. This study investigates the effects of leptin, in a concentration range usually observed in the plasma of patients with increased cardiovascular risk or measurable in patients with acute coronary syndromes, on tissue factor (TF) and cellular adhesion molecules (CAMs) expression in human coronary endothelial cells (HCAECs). We demonstrate that leptin induces transcription of mRNA for TF and CAMs by real-time PCR. In addition, we show that this adipokine promotes surface expression of TF and CAMs that are functionally active since we observed increased procoagulant activity and leukocyte adhesion on cell surface. Leptin effects appear modulated by eNOS-production of oxygen free radicals through the activation of the transcription factor, nuclear factor(NF)-kappaB, since L-NAME, Superoxide Dismutase and NF-kappaB inhibitors suppressed CAMs and TF expression. Data of the present study, although in vitro , indicate that leptin may exert direct effects on human coronary endothelial cells by promoting CAMs and TF expression and support the hypothesis that this adipokines, besides being involved in the pathophysiology of obesity, might play a relevant role as an active mediator linking obesity to cardiovascular disease.

C-reactive protein induces expression of matrix metalloproteinase-9: A possible link between inflammation and plaque rupture

BACKGROUND Matrix metalloproteases (MMPs) have been implicated in the pathogenesis of acute coronary syndromes (ACS). However, little is known about the mechanisms responsible for MMP expression in ACS. C-reactive protein (CRP) not only is an independent risk factor for cardiovascular events, but also may exert direct pro-atherosclerotic effects. Therefore, we aimed at determining whether CRP might induce MMP-9 in two different experimental conditions: 1) smooth muscle cells (SMCs) in vitro, and 2) patients with ACS. METHODS AND RESULTS Effects of increasing concentrations of CRP on MMP-9 expression were evaluated in vitro in human SMCs. TIMP-1 protein expression, the selective inhibitor of MMP-9, was also evaluated. CRP dose-dependently induced MMP-9 expression in SMCs by promoting MMP-mRNA transcription, as well as MMP-9 secretion. In contrast, no differences were found for TIMP-1 protein expression. In vivo, MMP-9 and CRP levels were measured in blood samples obtained from the aorta (Ao) and the coronary sinus (Cs) of patients with normal coronary arteries (controls, n=21), stable angina (n=24), and ACS (n=30). Both MMP-9 and CRP plasma levels were significantly increased across the coronary circulation only in patients with ACS. Interestingly, a significant correlation between MMP-9 and CRP plasma levels was found. CONCLUSIONS CRP induced MMP-9 expression and activity in human SMCs in culture; patients presenting with ACS have increased transcoronary plasma levels of MMP-9 and CRP with a significant correlation between these two markers. This may explain the heightened risk of coronary events in subjects with elevated levels of CRP.

Human urotensin II induces tissue factor and cellular adhesion molecules expression in human coronary endothelial cells: an emerging role for urotensin II in cardiovascular disease

Summary.  Background: Human urotensin II is an 11‐aminoacid peptide with a controversial role in the human cardiovascular system. Indeed, urotensin effects on vascular reactivity and in heart failure are well documented, while its potential role in the pathophysiology of athero‐thrombosis is still unknown. This study investigates the effects of urotensin on tissue factor (TF) and VCAM‐1/ICAM‐1 expression in human coronary endothelial cells (HCAECs). Methods and results: Urotensin induced TF‐mRNA transcription as demonstrated by real time PCR and expression of TF that was functionally active as demonstrated by procoagulant activity assay. In addition, urotensin induced expression of VCAM‐1 and ICAM‐1 as demonstrated by FACS analysis. VCAM‐1 and ICAM‐1 were functionally active because they increased leukocyte adhesivity to HCAECs. Urotensin‐induced expression of TF and of VCAM‐1/ICAM‐1 was mediated through the Rho A‐activation of the transcription factor, NF‐κB, as demonstrated by EMSA. Indeed, lovastatin, an HMG‐CoA reductase inhibitor, by modulating the Rho activation, and NF‐κB inhibitors, suppressed the urotensin effects on TF and CAMs. Conclusions: Data of the present study, although in vitro, describe the close relationship existing between urotensin II and athero‐thrombosis, providing for the first time support for the view that this peptide might have not only vasoactive functions but it might be an effector molecule able to induce a pro‐atherothrombotic phenotype in cells of the coronary circulation. Although future studies are required to clarify whether these mechanisms are also important in the clinical setting, this report supports an emerging new role for urotensin II in the pathogenesis and progression of cardiovascular disease.

HMG-CoA reductase inhibitors reduce nicotine-induced expression of cellular adhesion molecules in cultured human coronary endothelial cells.

Background: Smoking predisposes to the development of atherosclerosis and of its complications. The mechanisms responsible for these effects are not completely understood. We have investigated whether nicotine might promote a proatherosclerotic state in human coronary endothelial cells (HCAECs), studying the role of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in preventing these phenomena. Methods and Results: Real-time PCR showed that nicotine induced a dose-dependent increase in mRNA levels for vascular cellular adhesion molecule-1 (VCAM-1)/intercellular adhesion molecule-1 (ICAM-1). Fluorescent-activated cell sorting analysis showed that nicotine induced expression of functionally active VCAM-1/ICAM-1, since they increased leukocyte adherence to HCAECs. Oxygen free radicals, Rho A and nuclear factor ĸB (NF-ĸB) play a pivotal role in modulating these effects. Indeed, nicotine caused oxygen free radical production as well as activation of Rho A and NF-ĸB pathways, evaluated by malondialdehyde levels, pulldown assay and by electrophoretic mobility shift assay, respectively. Superoxide dimutase, Rho A (Y-27639) and NF-ĸB inhibitors (pyrrolidine dithiocarbamate ammonium, Bay 11-7082) suppressed nicotine effects on CAM expression. HMG-CoA reductase inhibitors prevented these nicotine-mediated effects by inhibiting free radical generation and by modulating activation of Rho A and NF-ĸB pathways. Conclusions: Nicotine promotes CAM expression on HCAECs, shifting them toward a proatherosclerotic state. These effects might explain, at least in part, the deleterious cardiovascular consequences of cigarette smoking. HMG-CoA reductase inhibitors play an important role in preventing these phenomena.

Successful use of the Cardiva Boomerang™ vascular closure device to close a brachial artery puncture site after emergency PTCA

Brachial artery access is a good alternative for performing percutaneous transluminal angioplasty when femoral access is contraindicated or not feasible. Although several closure devices are available for femoral access, haemostasis for brachial artery access is still achieved by manual compression with several potential complications, such as bleeding, pseudo-aneurysm formation, especially in patients in which heparin is administered, or thrombotic vessel occlusion. This first-in-human report describes the off-label brachial use of the Cardiva Boomerang™, a novel vascular closure device, which provides haemostasis using a temporary intravascular tampon, thus permitting the easier physiological closure of the puncture site without any important complications.

Transcoronary Th-17 lymphocytes and acute coronary syndromes: new evidence from the crime scene?

During the last two decades, a new perspective on atherosclerosis has prevailed based on accumulating evidence on the role of inflammatory and immune-competent cells, such as monocytes and T-lymphocytes, in contributing to the development of this disease. It is now generally accepted that a specific T-cell response is crucial in determining not only the development and growth of the atherosclerotic lesion, but also its fate toward a stable or an unstable pattern of evolution (i.e., rupture or ulceration), eventually leading to the clinical occurrence of acute coronary syndromes (ACS) [1]. In this respect, a complex interplay between T-cell subsets seems to regulate the fate of atherosclerotic lesions [2]. The adaptive effector CD4+ T helper (Th)-mediated immune response can be very heterogeneous, because of the existence of distinct cell subsets characterized by different profiles of cytokine production. Two polarized types of Th effectors, type 1 (Th-1) and type 2 (Th-2), were initially identified in bothmice and humans. Th-1 cells produce large amounts of interferon (IFN)-γ, while Th-2 cells are characterized by the production of IL-4, IL-5, and IL-13, but not IFN-γ. Our group has previously shown that Th-1 cells, by producing large amounts of γ-IFN, may contribute to

Tissue Factor/Factor FVII Complex Inhibitors in Cardiovascular Disease. Are Things Going Well?

Blood coagulation is a complex biological mechanism aimed to avoid bleeding in which a highly regulated and coordinated interplay of specific proteins and cellular components respond quickly to a vascular injury. However, when this mechanisms occurs in the coronary circulation, it has not a “protective” effect, but rather, it plays a pivotal role in determining acute coronary syndromes. Coagulation recognizes Tissue Factor (TF), the main physiological initiator of the extrinsic coagulation pathway, as its starter. Since TF:VIIa complex is the critical point of the blood coagulation cascade, it is a pharmacological attractive issue for the development of agents with anti thrombotic properties that can exert their activity by inhibiting complex formation and/or its catalytic activity. In fact, it is intuitive that an antithrombotic agent able to inhibit this initial step of the coagulation pathway has several theoretical, extremely important, advantages if compared with drugs active downstream the coagulation pathway, such as FXa or thrombin. The present report gives a brief overview of TF pathophysiology, highlighting the most recent advances in the field of inhibitors of the complex TF/VIIa potentially useful in cardiovascular disease.