Biomedical subjects

Plinio Cirillo

Publications and source records attributed to Plinio Cirillo.

7 recordsLinked to original sources

PubMed2005

C-reactive protein induces tissue factor expression and promotes smooth muscle and endothelial cell proliferation.

OBJECTIVE: Inflammation plays a pivotal role in atherothrombosis. In addition to being a prognostic marker for major cardiovascular events, recent data indicate that C-reactive protein (CRP) might directly promote atherothrombosis by exerting direct effects on vascular cells. The aim of the present study was to determine whether CRP might affect the prothrombotic and proliferative characteristics of endothelial (ECs) and smooth muscle cells (SMCs). METHODS AND RESULTS: Incubation of ECs and SMCs with CRP resulted in a dose-dependent activation of cell proliferation, which was mediated by activation of the p44/42 MAP Kinase (ERK 1/2) pathway. In addition, CRP also induced tissue factor (TF) expression in both cell types in a dose-dependent fashion, exerting its effect at the transcriptional level, as demonstrated by semiquantitative and by real time PCR. Activation of the transcription factor, NF-kappaB, by CRP was demonstrated by EMSA and by suppression of TF expression by the NF-kappaB inhibitor, pyrrolidine-dithio-carbamate ammonium. CONCLUSIONS: These data indicate that CRP exerts direct effects on ECs and SMCs by promoting proliferation and TF expression and support the notion that CRP, besides representing a marker of inflammation, is an effector molecule able to induce a pro-atherothrombotic phenotype in cells of the vessel wall.

Animals↗

PubMed2005

Role of beta2 adrenergic receptors in human atherosclerotic coronary arteries.

BACKGROUND: Adrenergic regulation of coronary vasomotion is balanced between alpha1-adrenergic-mediated (alpha1-AR) constriction and beta2-adrenergic-mediated (beta2-AR) relaxation. This study aimed at assessing the role of beta2-ARs in normal, mildly atherosclerotic, and stenotic human coronary arteries. METHODS AND RESULTS: During intracoronary (IC) infusion of increasing doses of the beta2-AR agonist salbutamol (0.15, 0.3, and 0.6 mug/min) and the endothelial vasodilator acetylcholine (1, 3, and 10 microg/min), we measured (1) changes in lumen diameter (LD) by quantitative coronary angiography in 34 normal, 55 mildly atherosclerotic, and 42 stenotic coronary artery segments and (2) changes in average peak velocity (APV) and coronary blood flow (CBF) with the use of Doppler flow wire in 11 normal, 10 mildly atherosclerotic, and 11 stenotic coronary arteries. In 6 of 11 stenotic coronary arteries, the protocol was repeated after an IC bolus (12 microg/kg) of the alpha-adrenergic blocker phentolamine. In 6 of 11 normal coronary arteries, the protocol was repeated after an IC infusion (60 micromol/min) of N(G)-monomethyl-L-arginine (L-NMMA), a nitric oxide inhibitor. Neither salbutamol IC infusion nor acetylcholine significantly changed heart rate or blood pressure, whereas L-NMMA slightly increased blood pressure. In normal coronary arteries, salbutamol increased LD (LD max %: 11+/-2, P<0.05), APV (APV max %: 53+/-17, P<0.05), and CBF (CBF max %: 57+/-17, P<0.05), whereas L-NMMA caused a blunted APV (APV max %: 27+/-6, P<0.05) and CBF (CBF max %: 29+/-6, P<0.05) response to salbutamol. In mildly atherosclerotic coronary arteries, the salbutamol increase in LD (LD max %: 10+/-2, P<0.05), APV (APV max %: 33+/-12, P<0.05), and CBF (CBF max %: 37+/-12, P<0.05) was preserved. In stenotic coronary arteries, salbutamol induced a paradoxical reduction in LD (LD max %: -6+/-2, P<0.05), APV (APV max %: -15+/-9, P<0.05), and CBF (CBF max %: -15+/-6, P<0.05), which was no longer observed after phentolamine. Acetylcholine increased LD (LD max %: 14+/-3, P<0.05), APV (APV max %: 61+/-20, P<0.05), and CBF (CBF max %: 67+/-19, P<0.05) in normal coronary arteries. In mildly atherosclerotic coronary arteries, acetylcholine induced a significant reduction in LD (LD max %: -15+/-2, P<0.05) and no changes in APV (APV max %: -6+/-13, P=NS) and CBF (CBF max %: -10+/-13, P=NS). In stenotic coronary arteries, acetylcholine significantly reduced LD (LD max %: -15+/-3, P<0.05), APV (APV max %: -15+/-9, P<0.05), and CBF (CBF max %: -15+/-6, P<0.05). CONCLUSIONS: In severely atherosclerotic coronary arteries, beta2-adrenergic vasodilatation is impaired, and this might contribute to alter the vasomotor balance, further precipitating myocardial ischemia during sympathetic activation.

Acetylcholine↗

PubMed2004

Tissue factor binding of activated factor VII triggers smooth muscle cell proliferation via extracellular signal-regulated kinase activation.

BACKGROUND: Tissue factor (TF) is the main initiator of coagulation in vivo. Recently, however, a role for TF as a cell receptor involved in signal transduction has been suggested. The aim of the present study was to assess whether activated factor VII (FVIIa) binding to TF could induce smooth muscle cell (SMC) proliferation and to clarify the possible intracellular mechanism(s) responsible for this proliferation. METHODS AND RESULTS: Cell proliferation was induced by FVIIa in a dose-dependent manner, as assessed by [3H]thymidine incorporation and direct cell counting, whereas no response was observed with active site-inhibited FVIIa (FVIIai), which is identical to FVIIa but is devoid of enzymatic activity. Similarly, no proliferation was observed when binding of FVIIa to TF was prevented by the monoclonal anti-TF antibody AP-1. Activation of the p44/42 mitogen-activated protein (MAP) kinase (extracellular signal-regulated kinases 1 and 2 [ERK 1/2]) pathway on binding of FVIIa to TF was demonstrated by transient ERK phosphorylation in Western blots and by suppression of proliferation with the specific MEK (MAP kinase/ERK kinase) inhibitor UO126. ERK phosphorylation was not observed with FVIIai or when cells were pretreated with AP-1. CONCLUSIONS: These data indicate a specific effect by which binding of FVIIa to TF on the surface of SMCs induces proliferation via a coagulation-independent mechanism and possibly indicate a new link between coagulation, inflammation, and atherosclerosis.

Animals↗

PubMed2003

Involvement of tissue factor pathway inhibitor in the coronary circulation of patients with acute coronary syndromes.

BACKGROUND: Tissue factor pathway inhibitor (TFPI) is the endogenous inhibitor of the extrinsic coagulation pathway; however, its involvement during thrombus formation in patients with acute coronary syndromes (ACS) is still unknown. METHODS AND RESULTS: Transcardiac (aorta/coronary sinus) free and total TFPI (free + lipoprotein-bound form) levels, as well as TFPI/factor Xa (FXa) complex levels, were measured in plasma samples obtained from patients with acute myocardial infarction undergoing primary PTCA and patients with unstable angina undergoing urgent PTCA. Patients with stable angina undergoing elective PTCA served as controls. In addition, prothrombin fragment 1+2 and fibrinopeptide A plasma levels were measured. Samples were collected at baseline, after PTCA, and after stent deployment. In patients with ACS, both total and free TFPI plasma levels in the coronary sinus were significantly lower than the corresponding levels measured in the aorta at any time point of the study; conversely, a significant increase in TFPI/FXa complex plasma levels was observed in the coronary sinus as compared with the aorta. In contrast, in patients with stable angina, no differences were observed in TFPI and TFPI/FXa levels at baseline in the coronary sinus as compared with the aorta. CONCLUSIONS: TFPI is involved in the process of thrombus formation in vivo in patients with ACS, which suggests a potential role for TFPI in modulating coronary thrombosis.

Aged↗

PubMed2003

Induction of tissue factor in the arterial wall during recurrent thrombus formation.

OBJECTIVE: Tissue factor (TF) is normally expressed at low levels in the media of blood vessels, but it is readily induced after vessel injury. It is not known whether vascular damage per se or thrombus formation is responsible for this phenomenon. METHODS AND RESULTS: Cyclic flow variations (CFVs), attributable to recurrent thrombus formation, were induced in stenotic rabbit carotid arteries with endothelial injury. CFVs were observed for 30 minutes and 2, 4, and 8 hours in different groups of animals. Another group of rabbits pretreated with hirudin before inducing arterial damage to inhibit thrombus formation was observed for 8 hours. Arterial sections were immunostained for TF. Undamaged arteries served as controls. In additional rabbits, in situ hybridization experiments were performed. No TF expression was observed in the media of control vessels, whereas a progressive increase in TF mRNA and protein expression was observed in carotid arteries as CFVs progressed. No increase in TF expression was observed in animals pretreated with hirudin. In vitro experiments demonstrated that TF mRNA is induced in smooth muscle cells stimulated with activated platelets as well as with some platelet-derived mediators. CONCLUSIONS: This phenomenon may contribute to sustain intravascular thrombus formation after the initial thrombogenic stimulus.

Animals↗

PubMed2003

Activated platelets stimulate tissue factor expression in smooth muscle cells.

UNLABELLED: Tissue factor (TF)-induced activation of the coagulation plays a key role in the pathophysiology of acute coronary syndromes. Because TF represents the initial trigger of the coagulation cascade, its expression in the arterial wall is tightly regulated. OBJECTIVE: To determine whether and which soluble mediators released during platelet activation may upregulate TF expression in smooth muscle cells (SMCs). METHODS AND RESULTS: Rabbit SMCs were challenged with collagen-activated platelets and their effects on TF mRNA transcription and protein expression were evaluated at different time points (30 min, 1, 2, 4, 8, 12 and 24 h) by RT-PCR, immunofluorescence and a two-stage colorimetric assay. A progressive increase in TF mRNA, peaking at 2 h, was evident in SMCs stimulated with activated platelets with respect to baseline. The increase in TF mRNA expression was associated with a parallel increase in TF protein, as demonstrated by immunofluorescence and by colorimetric assay. In a different set of experiments, selected platelet-derived soluble mediators were shown to induce TF mRNA expression. CONCLUSIONS: Activated platelets upregulate TF, via release of several soluble mediators, in a cell population widely expressed in the vessel wall and in atherosclerotic plaques, such as SMCs. This phenomenon might play an important role in sustaining thrombus formation in vivo.

Animals↗

PubMedDate not supplied

Estimation of coronary flow reserve by Tc-99m sestamibi imaging in patients with coronary artery disease: comparison with the results of intracoronary Doppler technique.

BACKGROUND: This study compared coronary flow reserve (CFR) estimated by technetium 99m sestamibi imaging with the results obtained with intracoronary Doppler in patients with coronary artery disease. Intraobserver and interobserver reproducibility of the radionuclide-estimated CFR was also assessed. METHODS AND RESULTS: Fourteen consecutive patients (mean age, 54 +/- 7 years) with documented coronary artery disease in whom percutaneous coronary intervention was planned underwent dipyridamole (0.74 mg/kg) sestamibi imaging and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the pulmonary artery and myocardial counts from single photon emission computed tomography images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. In the study vessels, CFR was 1.36 +/- 0.43 as estimated by sestamibi and 1.39 +/- 0.42 by intracoronary Doppler ( P = .69). A significant relationship between CFR estimated by sestamibi and CFR obtained by intracoronary Doppler was observed ( r = 0.85, P < .001). On Bland-Altman analysis, the mean difference between CFR by sestamibi and by Doppler was 0.03 and the intraclass correlation coefficients for intraobserver and interobserver reproducibility were high (all P < .001) for both global and regional CFR. CONCLUSIONS: This study demonstrates a good agreement between CFR estimated by sestamibi imaging and by intracoronary Doppler results and a lack of intraobserver and interobserver variability of this noninvasive approach.

Algorithms↗