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Defects in the synthesis and breakdown of the extracellular matrix (ECM) are now seen as key processes in the development of atherosclerosis and its thrombotic complications. Correlations have been observed between circulating levels of ECM biomarkers and the clinical manifestations of and risk factors for atherosclerosis. Several matrix metalloproteinases (MMPs), endopeptidases that can degrade the ECM, such as MMP-9 and MMP-10, play important roles in the pathophysiology of atherothrombosis and contribute to the expansion of abdominal aortic aneurysms. Moreover, they may also be useful biomarkers of atherosclerotic risk and serve as predictors of coronary and cerebrovascular disease recurrence. Although at present the effect of tissue inhibitors of MMPs (TIMPs) on cardiovascular disease prognosis is still uncertain, the ECM could be a promising therapeutic target in atherothrombotic disease, and several MMP inhibitors are currently undergoing clinical trials.

The recognition that inflammation is a hallmark of atherosclerotic disease and its complications has led to a series of studies reporting high prevalence of atherosclerosis in chronic inflammatory diseases. Indeed, chronic immune diseases, such as systemic lupus erythematosus and rheumatoid arthritis, are associated with proinflammation, accelerated atherosclerosis and increased incidence of cardiovascular disease. Since the susceptibility towards cardiovascular events cannot be explained by classical risk factors, disease-specific pathways have been put forward as additional risk factors, potentially important for future prevention and treatment of atherosclerosis associated with chronic inflammatory diseases.

Objectives: Assessment of vascular risk in asymptomatic patients and the response to medical therapy is a major challenge for prevention of cardiovascular events. Our aim was to identify proteins differentially released by healthy versus atherosclerotic arterial walls, which could be found in plasma and serve as markers of atherosclerosis., Methods and Results: We have analyzed supernatants obtained from cultured human carotid plaques and healthy arteries by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry ProteinChip System. Surface-enhanced laser-desorption/ionization analysis unveiled an 18.4-kDa peak released in lower amount by carotid plaques than normal endarteries. This protein was identified as soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK). To confirm that sTWEAK was the protein of interest, Western blot and enzyme-linked immunosorbent assay were performed. Both techniques confirmed that sTWEAK levels were decreased in carotid plaque supernatants. Subsequent measurement of sTWEAK in plasma showed a reduced concentration in subjects with carotid stenosis (N=30) compared with healthy subjects matched by sex and age (N=28) (P<0.001). Furthermore, in a test population of 106 asymptomatic subjects, we showed that sTWEAK concentrations negatively correlated with the carotid intima-media thickness (r=-0.4; P<0.001), an index of subclinical atherosclerosis., Conclusions: These results suggest that sTWEAK could be a potential biomarker of atherosclerosis.

Objective: Data suggest that matrix metalloproteinase-9 (MMP-9) has a role in atherosclerosis. The phagocytic NADPH oxidase has been also associated with atherosclerosis. This study aimed to investigate the association between phagocytic NADPH oxidase and MMP-9 in human atherosclerosis., Methods and Results: In vitro experiments performed in human monocytes showed that NADPH oxidase activation enhanced MMP-9 secretion and activity, determined by enzyme-linked immunosorbent assay and zymography, respectively. Immunohistochemical study showed that phagocytic NADPH oxidase localized with MMP-9 in endarterectomies from patients with carotid stenosis. In addition, a positive relationship (P<0.001) was found between phagocytic NADPH oxidase-dependent superoxide production determined with lucigenin and plasma MMP-9 levels in 188 asymptomatic subjects free of overt clinical atherosclerosis. In multivariate analysis, this association remained significant after adjustment for cardiovascular risk factors. Interestingly, subjects in the upper quartile of superoxide production exhibited the highest values of MMP-9, oxidized low-density lipoprotein, nitrotyrosine, carotid intima media thickness, and an increased presence of carotid plaques., Conclusions: Enhanced NADPH oxidase-dependent *O2(-) production stimulates MMP-9 in monocytes and this relationship may be relevant in the atherosclerotic process. Moreover, MMP-9 emerges as an important mediator of the phagocytic NADPH oxidase-dependent oxidative stress in atherosclerosis.

The clinical utility of a biomarker depends on its ability to identify high-risk individuals to optimally manage the patient. A new biomarker would be of clinical value if it is accurate and reliable, provides good sensitivity and specificity, and is available for widespread application. Data are accumulating on the potential clinical utility of integrating imaging technologies and circulating biomarkers for the identification of vulnerable (high-risk) cardiovascular patients. A multi-biomarker strategy consisting of markers of inflammation, hemostasis and thrombosis, proteolysis and oxidative stress, combined with new imaging modalities (optical coherence tomography, virtual histology plus IVUS, PET) can increase our ability to identify such thombosis-prone patients. In an ideal scenario, cardiovascular biomarkers and imaging combined will provide a better diagnostic tool to identify high-risk individuals and also more efficient methods for effective therapies to reduce such cardiovascular risk. However, additional studies are required in order to show that this approach can contribute to improved diagnostic and therapeutic of atherosclerotic disease.

It is now widely accepted that atherosclerosis is a complex chronic inflammatory disorder of the arterial tree associated with several risk factors. From the initial phases to eventual rupture of vulnerable atherosclerotic plaques, a low-grade inflammation, also termed microinflammation, appears to play a key pathogenetic role. Systemic inflammatory markers (C reactive protein, cytokines adhesion molecules) also play a role in this process. Experimental and clinical evidence suggests that cyclooxygenase-2 (COX-2), an enzyme which catalyzes the generation of prostaglandins from arachidonic acid, also contributes to lesion formation. Recent reports by our group have demonstrated increased monocyte COX-2 activity and the production of prostaglandin E2 in relation to cardiovascular risk factors and subclinical atherosclerosis in asymptomatic subjects. Our findings support the notion that the COX-2/prostaglandin E2 axis may have a role, raising the question as to whether its selective inhibition might be an attractive therapeutic target in atherosclerosis. COX-2 inhibitors, collectively called "coxibs" (celecoxib, rofecoxib, valdecoxib, lumiracoxib, etc), held a promise as anti-inflammatory drugs without the some of the side effects of aspirin or non steroidal antiinflammatory agents. However, clinical studies raise several clinically relevant questions as to their beneficial role in atherosclerosis prevention, because of increased thrombogenicity and cardiovascular risk, and therefore coxibs should be restricted in atherosclerosis-prone patients.

Objectives: We examined the effect of C-reactive protein (CRP) on matrix metalloproteinase (MMP) and inhibitor expression in endothelial cells and in patients with clinical and subclinical atherosclerosis., Background: In addition to predicting atherosclerotic vascular disease, CRP may directly promote a proinflammatory/proatherosclerotic phenotype., Methods: Human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAECs) were incubated in the presence or absence of CRP (50 mug/ml). Microarray analysis, real-time polymerase chain reaction, immunological and activity assays for MMPs were performed. Specific inhibitors of mitogen-activated protein kinase pathway were used. The MMP-1 and -10 plasma levels were measured in apparently healthy subjects (n = 70). Immunolocalization of CRP, MMP-1, and MMP-10 was performed in human mammary arteries and carotid endarterectomy specimens., Results: C-reactive protein augmented MMP-1 and -10 messenger ribonucleic acid expression in HUVEC (p < 0.05) and HAEC (p < 0.01). C-reactive protein stimulation also increased MMP-1 and -10 protein in conditioned culture medium (p < 0.001), as well as MMP activity (p = 0.001). Specific inhibition of p38 or MEK abolished the CRP induction of the MMP-1, whereas MMP-10 induction blockade required the simultaneous inhibition of p38 and Jun N-terminal kinase pathways. Subjects with CRP values >3 mg/l (n = 37) had increased plasma MMP-1 and -10 (p < 0.05), the association being significant after adjustment for confounding variables (p = 0.04 and p = 0.008, respectively). The MMP-10 levels were elevated in subjects with higher carotid intima-media thickness (p = 0.009). Increased CRP and MMP-10 colocalized in endothelial layer and macrophage-rich areas in advanced atherosclerotic plaques., Conclusions: Increased local and systemic CRP-related MMP activation might provide a link between inflammation and plaque vulnerability.

It is now widely accepted that atherosclerosis is a complex chronic inflammatory disorder of the arterial tree associated with several risk factors. From the initial phases of leukocyte recruitment to eventual rupture of vulnerable atherosclerotic plaques, a low-grade inflammation, also termed microinflammation, appears to play a key pathogenetic role. Experimental and clinical evidence suggests that cyclooxygenase-2 (COX-2), an enzyme which catalyzes the generation of prostaglandins from arachidonic acid, also contributes to lesion formation. COX-2 has been detected in macrophages, smooth muscle cells and endothelial cells in human atherosclerotic lesions. Several studies have also reported the presence of COX-2 in the shoulder region of atherosclerotic plaques, mainly colocalizing with macrophages and MMPs, enzymes that are involved in the destabilization of atherosclerotic plaques, leading to rupture and atherothrombotic syndromes (i.e. acute myocardial infarction). We have recently assessed monocyte COX-2 activity and the production of PGE(2) in a population of apparently healthy subjects free from clinically overt atherosclerosis. We found an association between increased PGE(2) and increasing number of cardiovascular risk factors and carotid intima-media thickness, a noninvasive surrogate marker of atherosclerosis, independently of traditional and non traditional cardiovascular risk factors. Our findings support the notion that the COX-2/PGE(2)axis may have a role in atherosclerosis, and this might be an attractive therapeutic target. COX-2 inhibitors, collectively called coxibs (celecoxib, rofecoxib, valdecoxib, lumiracoxib, etc), held a promise of improved treatment of arthritis without the gastrointestinal side effects associated with aspirin and other nonsteroidal anti-inflammatory drugs. However, clinical studies raise several clinically relevant questions as to their beneficial role in atherosclerosis prevention, because of increased thrombogenicity and cardiovascular risk. Only well designed large scale clinical trials can provide the answer as to the net effect of selective COX-2 inhibition on cardiovascular events before this new class of anti-inflammatory drugs can be incorporated into the armamentarium of atherosclerosis.

The formation of a fibrin clot is one of the key events in atherothrombotic vascular diseases, such as myocardial infarction, ischemic stroke and peripheral arterial disease. Fibrin is formed from a circulating precursor, fibrinogen, by the action of thrombin. Both genetic and environmental factors are important determinants of the circulating fibrinogen levels. Epidemiologic studies have demonstrated a role for this hemostatic protein in the prediction of cardiovascular disease. As an acute-phase reactant, fibrinogen is also a marker of inflammation. Likewise, recent studies from our group have shown that increased fibrinogen levels represent a marker of subclinical atherosclerosis, likely to be useful in the identification of asymptomatic subjects at risk for cardiovascular disease.

Arterial thrombosis results from complex gene-gene and gene-environment interactions. While Vichow's triad was traditionally referred to venous thrombosis, the same process has been applied to arterial thrombosis: abnormalities of hemorrheology, abnormal blood constituents and abnormal vessel wall/endothelial dysfunction. Research carried out in the past decade has identified several polymorphisms in genes related to coagulation and fibrinolytic factors, platelet receptors, endothelial dysfunction, homocysteine metabolism, endothelial nitric oxide synthase, abnormal blood flow and oxidative stress. Whereas the individual contribution of each polymorphism to the overall cardiovascular risk seems to be modest, multiple gene-gene and gene-environment interactions appear more relevant in the pathogenesis of arterial thrombosis.

Aims: Cyclooxygenase-2 (COX-2)-mediated prostaglandin production by activated macrophages is associated with inflammation and atherosclerosis. We investigated the relationship between COX-2-mediated prostaglandin-E2 (PGE2) release, cardiovascular risk factors, and carotid atherosclerosis in apparently healthy subjects., Methods and Results: PGE2 release by lipopolysaccharide-stimulated blood monocytes was measured by ELISA in 291 subjects (76.5% men, mean age 58) who underwent global vascular risk assessment and carotid ultrasonography. COX-2 expression (real-time RT-PCR) was analysed in a subgroup of 100 subjects (76% men, mean age 59). Inducible PGE2 production was associated with smoking and diabetes (P<0.05), but not with arterial hypertension, dyslipidaemia, or obesity. Subjects in the highest tertile of PGE2 (>8.1 ng/mL) had significantly higher mean carotid intima-media thickness (IMT) than those in the lowest tertile (P<0.01). No significant differences among tertiles were observed in the levels of inflammatory markers (C-reactive protein, fibrinogen, and von Willebrand factor). The association between PGE2 and carotid IMT remained statistically significant (P=0.012) after adjustment for a number of cardiovascular and inflammatory risk factors. A correlation between COX-2 expression and PGE2 production was observed (P<0.005)., Conclusions: COX-2-mediated PGE2 overproduction by stimulated monocytes might provide a new marker of subclinical atherosclerosis in asymptomatic subjects exposed to cardiovascular risk factors.

Background and Objectives: Fibrinogen has been found to be an independent risk factor for cardiovascular disease. The aim of this study was to validate the measurement of plasma fibrinogen as a marker of subclinical atherosclerosis in a series of asymptomatic subjects (n=519, median age 55.5 years, 80% men)., Design and Methods: All individuals had a complete clinical examination, lipid profile (cholesterol and its high and low density lipoprotein fractions and triglycerides), global vascular risk assessment (PROCAM), and B-mode ultrasonography of the carotid arteries to determine the intima-media thickness (IMT) and the presence of atheroma plaques. C-reactive protein (CRP), and von Willebrand factor (vWF) were also measured in all subjects as markers of inflammation/endothelial damage., Results: In the univariate model, a positive relationship was found between plasma fibrinogen concentration and carotid IMT (p<0.001). Fibrinogen concentration also correlated positively with age (p<0.001), systolic blood pressure (p<0.001), smoking (p<0.05), diabetes (p<0.05), PROCAM (p<0.001), CRP and vWF (p<0.001). In the multivariate analysis, the association of fibrinogen with carotid IMT remained significant (p=0.008) after adjustment for all parameters analyzed., Interpretation and Conclusions: In a population sample of adults without clinically overt atherosclerotic disease, elevated fibrinogen levels was related to carotid IMT independently of a wide range of important confounding variables. Plasma fibrinogen may represent a systemic marker of carotid atherosclerosis.

Background: We examined the influence of the 4G/5G PAI-1 (plasminogen activator inhibitor) genotype on Angiotensin II (Ang II)-induced PAI-1 expression by human endothelial cells (HUVEC) in the presence and absence of AT1-receptor blocker losartan, and screened for this polymorphism in relation to plasma PAI-1 and arterial pressure in apparently healthy subjects., Methods and Results: Genotyped cultured HUVEC were incubated with Ang II (10(-8) M) with or without losartan up to 24 h. PAI-1 mRNA was determined in cell extracts and protein and activity assessed in supernatants and extracellular matrix (ECM). Ang II increased PAI-1 mRNA and activity in a genotype-dependent manner, higher values observed for 4G/4G HUVEC compared with 4G/5G and 5G/5G genotypes (p<0.05). Laser confocal microscopy and Western blot analysis showed increased PAI-1 protein within ECM in Ang II-stimulated cultures. PAI-1 expression and protein secretion induced by Ang II in 4G/4G HUVEC was completely inhibited by preincubation with 0.05 microM losartan (p<0.01), indicating an AT1-mediated effect. In a group of hypertensives homozygous for the 4G allele, PAI-1 antigen was significantly increased (51.0+/-10.1 ng/ml) compared with normotensives (28.3+/-4.0 ng/ml) and hypertensives carrying the 5G allele (p<0.05)., Conclusions: The 4G/5G PAI-1 polymorphism determines the endothelial PAI-1 upregulation by Ang II and the inhibitory response to losartan. Analysis of PAI-1 genotypes may help identifying subgroups of hypertensives at higher cardiovascular risk.

Background and Purpose: Thrombin, a central enzyme in the clotting cascade, plays a role not only in thrombosis but also in the progression of atherosclerosis. We studied the relationship between prothrombin fragment 1+2 (F1+2), a specific marker of thrombin generation in vivo, and carotid intima-media thickness (IMT), an index of subclinical atherosclerosis., Methods: We examined 181 asymptomatic middle-aged subjects (mean age 55.6 years, 76.7% men) free of overt clinical atherosclerotic disease. F1+2 was measured by enzyme-linked immunosorbent assay and IMT by duplex ultrasonography of carotid artery. Multiple linear regression analysis was used to assess the relationship between the 2 parameters., Results: Compared with individuals in the lowest tertile of F1+2, those in the upper tertile (>0.55 nmol/L) showed significantly higher IMT (P<0.01). In correlation analysis, a positive relationship was found between plasma F1+2 and carotid IMT. F1+2 also correlated positively with cholesterol (P<0.008) and low-density lipoprotein cholesterol (P<0.005), but not with blood pressure or body mass index. In the multivariate analysis, the association of F1+2 with carotid IMT remained significant (P<0.001) after adjustment for age, sex, body mass index, systolic blood pressure, cholesterol, diabetes, and smoking., Conclusions: In a population sample of adults without clinically overt atherosclerotic disease, the plasma levels of F1+2 were significantly associated with carotid IMT, suggesting a relationship between thrombin generation and the development atherosclerosis.

As it is well-known, a thrombus evolving into a disrupted/eroded atherosclerotic plaque causes most acute coronary syndromes. Plaque stabilization via reduction of the lipid core and/or thickening of the fibrous cap is one of the possible mechanisms accounted for the clinical benefits displayed by different anti-atherosclerotic strategies. The concept of plaque stabilization was developed to explain how lipid-lowering agents could decrease adverse coronary events without substantial modifications of the atherosclerotic lesion. A number of imaging modalities (vascular ultrasound, MRI, and coronary computed tomography) are used for non-invasive assessment of atherosclerosis; most of them can identify luminal stenosis, wall thickness and plaque volume and composition, and can even characterize the rupture-prone vulnerable plaques. Several classes of drugs, including statins, ACE inhibitors, -blockers, and antithrombotics, are able to reduce the plaque burden and the incidence of cardiovascular events; this may be attibutable, at least in part, to plaque-stabilizing effects and the improvement of endothelial dysfunction.

Objectives: We have investigated whether the A1166C polymorphism of the angiotensin II type 1 (AT1) receptor gene modulates the effects of angiotensin II on collagen type I turnover and myocardial stiffness in hypertension., Methods: We studied 255 hypertensive patients before and after 1 year of treatment with either losartan (n = 185) or atenolol (n = 70). Serum concentrations of the carboxy-terminal propeptide of procollagen type I (PIP) and the carboxy-terminal telopeptide of collagen type I (CITP), markers of extracellular collagen type I synthesis and degradation, respectively, were measured by specific radioimmunoassays. Left ventricular chamber stiffness (KLV), was determined from the deceleration time of the early mitral filling wave, as measured by Doppler echocardiography. Hypertensives were genotyped by polymerase chain reaction and divided in two subgroups: AA (n = 126) and AC/CC (n = 129)., Results: Baseline PIP and KLV were increased (P < 0.01) in AA hypertensives compared with AC/CC hypertensives. No changes in baseline CITP were observed between the two subgroups of hypertensives. Confounding factors were similar between the two subgroups of hypertensives. Administration of losartan was associated with reduction (P < 0.01) in PIP and KLV in AA hypertensives but not in AC/CC hypertensives. Treatment with atenolol did not change PIP and KLV in either subgroup of hypertensives. No changes in CITP were observed with the two treatments., Conclusion: These findings suggest that the A1166C polymorphism of the AT1 receptor gene is associated with collagen type I synthesis and myocardial stiffness in patients with hypertensive heart disease.

Background: Proteolytic imbalance might determine arterial remodeling and plaque destabilization in atherosclerotic vessels. The aim of this study was to examine differences in the patterns of metalloproteinases (MMPs) and MMP inhibitor (TIMP-1) expression in advanced human atheromas, both in relation to the plaque features and the vascular bed involved., Methods and Results: Immunohistochemistry for MMP-1, -3, -9 and TIMP-1 as well as the collagen content were measured in vascular sections from patients undergoing peripheral revascularization (carotid n=11, femoral n=23) and aorto-coronary bypass surgery (mammary arteries n=20, as controls). Increased expression of all MMPs was detected in atherosclerotic as compared with control sections (P<0.01). Aneurysmal plaques showed a significant increase of MMP-1 and-3 and a reduction in total collagen (P<0.05) in relation to occlusive lesions. Calcification areas in atherosclerotic plaques were consistently associated with increased TIMP-1 expression (P<0.01). Finally, MMP-9 expression was higher in occlusive lesions from carotid than femoral arteries (P<0.01)., Conclusions: Aneurysm lesions expressed higher MMP-1 and-3 expression than occlusive plaques, and MMP-9 was mainly detected in carotid as compared with femoral arteries. TIMP-1 was associated with arterial calcification. These differences in the MMPs/TIMP-1 expression might determine the evolution of advanced atherosclerotic plaques and contribute to its vulnerability.

To evaluate the efficacy and safety of conversion from cyclosporine to tacrolimus, we analyzed 55 kidney transplant patients who were converted due to cosmetic reasons in 42 patients, acute rejection in 2 patients, and other causes in 11 patients. At the doses and levels used, the development of diabetes mellitus was minimized. Disappearance of cosmetic side-effects and improvement of cardiovascular risk factors, together with conservation of renal function, encourage us to use tacrolimus as an efficacious and safe immunosuppressive therapy.

The p22(phox) subunit is an essential protein in the activation of NAD(P)H oxidase. Here we report the preliminary characterisation of the human p22(phox) gene promoter. The p22(phox) promoter contains TATA and CCAC boxes and Sp1, gamma-interferon and nuclear factor kappaB sites. We screened for mutations in the p22(phox) promoter and identified a new polymorphism, localised at position -930 from the ATG codon, which was associated with hypertension. Mutagenesis experiments showed that the G allele had higher promoter activity than the A allele. These results suggest that the -930(A/G) polymorphism in the p22(phox) promoter may be a novel genetic marker associated with hypertension.

Degradation of extracellular matrix, particularly interstitial collagen, promotes plaque instability and contributes to restenosis after vascular injury. We have explored the effects of vitamins C and E on the collagen content and metalloproteinase-1 (MMP-1) expression after angioplasty in hypercholesterolemic pigs. Iliac angioplasty was performed on 18 minipigs divided into three diet groups: a normal-cholesterol (NC), a high-cholesterol (HC) and a high-cholesterol plus vitamins C+E (HCV). Four weeks later, after sacrifice, the vascular collagen content and MMP-1 protein expression, along with the plasma caseinolytic activity and lipid peroxidation, were measured. MMP-1 was also determined in arterial rings stimulated with native low-density lipoproteins (LDL) isolated from experimental groups. Cholesterol-rich diet augmented plasma lipid peroxidation (P<0.05), reduced the collagen content and increased vascular MMP-1 expression after injury (P<0.05). Enhanced caseinolytic activity (identified as MMP-1) was also observed in HC plasma samples and in supernatants from arterial rings incubated with HC-LDL. Vitamins C and E markedly increased neointimal collagen content (P<0.01), reduced the hypercholesterolemia-induced changes in vascular MMP-1 (P<0.05) and diminished plasma and ex vivo caseinolytic activity. Vitamins C and E may help stabilize atherosclerotic plaque after angioplasty and favor vascular remodeling by increasing collagen content and reducing vascular MMP-1 expression in porcine hypercholesterolemia.

In this work we study the effect of several covariates on a censored response variable with unknown probability distribution. A semiparametric model is proposed to consider situations where the functional form of the effect of one or more covariates is unknown, as is the case in the application presented in this work. We provide its estimation procedure and, in addition, a bootstrap technique to make inference on the parameters. A simulation study has been carried out to show the good performance of the proposed estimation process and to analyse the effect of the censorship. Finally, we present the results when the methodology is applied to AIDS diagnosed patients.

Background: Fibrinogen has been found to be an independent risk factor for cardiovascular disease. Both genetic and environmental factors contribute to its variability in plasma. However, whether the relation between fibrinogen and carotid intima-media thickness (IMT) is independent of those factors has not been established. Therefore, the aim of this study was to investigate the relations of plasma fibrinogens and the -455 G/A Bbeta-fibrinogen polymorphism with the carotid IMT in a series of asymptomatic subjects., Methods: Markers of inflammation, C-reactive protein (CRP) and leukocytes, and endothelial perturbation (von Willebrand factor, vWF) were measured in 135 subjects. All individuals underwent a complete clinical examination and lipid measurements (cholesterol and its fractions HDL and LDL and triglycerides). The carotid IMT was measured by B-mode ultrasound in the common carotid artery., Results: Patients in the highest fibrinogen tertile had a significantly higher BMI (p < 0.01), LDL-cholesterol (p < 0.01), leukocyte count, CRP and vWF (p < 0.001). In the univariate model a strong positive relationship was found between plasma fibrinogen and carotid IMT (p < 0.01). Fibrinogen also correlated positively with age, BMI, arterial systolic pressure, cholesterol, cholesterol-LDL, smoking, CRP and vWF (p < 0.01). In the multivariate analysis, the association of fibrinogen with carotid IMT remained significant (p < 0.01) after adjustment for all the parameters analyzed., Conclusion: In a population sample of adults without clinically overt atherosclerotic disease, elevated fibrinogen was related to carotid IMT independent of a wide range of important confounding variables., (Copyright 2003 S. Karger AG, Basel)

The increase in nitric oxide (NO) production in lipopolysaccharide (LPS)-induced sepsis is thought to contribute to the development of shock. However, NO could also play an antithrombotic role. Little is known about the modulating effect of NO on the endothelial overexpression and production of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) occurring in endotoxemia. We analyzed the effect of N(G)-nitro-L-arginine-methyl-ester (L-NAME), an inhibitor of NO synthases, and S-nitroso-N-acetyl-D,L-penicillamine (SNAP), a NO donor, on the expression and synthesis of TF and PAI-1 by LPS-challenged human umbilical vein endothelial cells (HUVEC): L-NAME enhanced the increase in TF mRNA and antigen levels (P <0.05) observed in LPS-treated HUVEC; SNAP down-regulated the LPS-induced TF increment (p <0.05). However, no effects of NO on regulation of the LPS-dependent increase in PAI-1 could be seen. Thus, NO could play an antithrombotic role in sepsis by down-regulating the endothelial overexpression and production of TF.

This paper describes a method proposed for a censored linear regression model that can be used in the context of survival analysis. The method has the important characteristic of allowing estimation and inference without knowing the distribution of the duration variable. Moreover, it does not need the assumption of proportional hazards. Therefore, it can be an interesting alternative to the Cox proportional hazards models when this assumption does not hold. In addition, implementation and interpretation of the results is simple. In order to analyse the performance of this methodology, we apply it to two real examples and we carry out a simulation study. We present its results together with those obtained with the traditional Cox model and AFT parametric models. The new proposal seems to lead to more precise results., (Copyright 2002 John Wiley & Sons, Ltd.)

Objective: The format of inpatient morning reports and ward rounds is infrequently applied in ambulatory medical education. Published reports, however, suggest that this format provides for learner-centered, case-based discussions rather than topic-based lectures in the ambulatory setting.(1) We developed an ambulatory morning report with the specific objective of enhancing evidence-based medical inquiry among our pediatrics housestaff., Description: We developed a pediatric encounter form (PEF) by adapting and modifying an instrument described by Paccione et al.(2) The PEF was to be used by residents to document pertinent information and unanswered questions about patients seen during each ambulatory clinic session. Prompts were provided for documenting the patient's primary complaints, the patient's disposition, and questions that the resident needed answered. The PEF was piloted among a group of residents and faculty. The final version incorporated both resident and faculty input. Each resident was asked to complete a PEF for a maximum of two patients per clinic session. We did not direct residents as to what types of questions to formulate. All completed forms were maintained in a central folder. Next, we instituted a one-hour "Ambulatory Rounds" seminar once a week at lunch-time. During these seminars, faculty selected PEF cases from the previous week for discussion. Residents presented the cases and discussed the reasons behind the formulation of their questions. Faculty facilitated and guided residents toward resources for answering their questions. Faculty also helped residents to reformulate their questions to reflect an evidence-based medicine approach. At the end of each seminar, residents elected to research specific questions and present brief reports at the next seminar. To test the hypothesis that residents will formulate a higher proportion of evidence-based medicine (EBM) questions over time, we collected and analyzed 445 questions asked by 12 residents between July 2000 and August 2001. We categorized questions into EBM and non-EBM questions based on faculty assessment. We performed a trend analysis using chi-square to compare questions from July 2000 (as reference value) with the six-month periods of August 2000 to January 2001 and February to August 2001. By the end of the observation period, the proportion of EBM questions had significantly increased from 13% in July 2000 to 28% in the first six-month period and 59% in the second six-month period (p < 0.001)., Discussion: We describe a new application of outpatient morning reports. This format has been very well received. Housestaff gave the ambulatory rounds an average rating of 4.3 (out of 5) on a Likert scale. Our experience suggests that this format not only provides a forum for case-based learning but can be successfully used to enhance the principles of evidence-based medicine among residents.

Objectives: Recent epidemiologic studies have shown that obesity is associated with elevated blood concentrations of prothrombotic-proinflammatory factors and markers of endothelial dysfunction such as fibrinogen, C-reactive protein (CRP), von Willebrand factor (vWF), and homocysteine. We have assessed whether these markers are associated with percentage of body fat (BF), insulin sensitivity as well as with leptin concentrations., Design and Methods: Twenty-five men aged 49.6 +/- 12.7 yr (mean +/- SD) underwent whole-body air displacement plethysmography (Bod-Pod(R)) for estimating BF. Blood analyses for leptin and several other metabolic and cardiovascular markers were carried out., Results: Obese subjects had higher levels as compared to controls of BF (37.5 +/- 5.1 vs. 26.0 +/- 6.6, p < 0.01), fibrinogen (3.30 +/- 0.43 vs. 2.67 +/- 0.11, p < 0.01), vWF (136.4 +/- 50.4% vs. 81.6 +/- 12.6%, p < 0.05), and leptin (17.6 +/- 8.7 vs. 6.2 +/- 3.3, p < 0.01), lower concentrations of HDL-cholesterol (1.09 +/- 0.20 vs. 1.51 +/- 0.10, p < 0.001) and lower QUICKI (1/[log(Ins(0)) + log(Glu(0))]) (0.31 +/- 0.03 vs. 0.34 +/- 0.02, p < 0.05). No significant changes were observed in CRP (5.7 +/- 3.4 vs. 3.8 +/- 1.6, p = 0.327) and homocysteine (9.4 +/- 4.2 vs. 8.3 +/- 0.9, p = 0.749). A positive correlation was observed between BF and fibrinogen (r = 0.67, p = 0.0003). Plasma leptin concentrations were correlated with fibrinogen (r = 0.71, p = 0.0001) and CRP (r = 0.43, p = 0.044). After adjustment for BF leptin emerged as a significant predictor of fibrinogen (beta = 0.47, p = 0.023; R(2) = 0.59, p < 0.001). QUICKI was positively correlated with HDL-cholesterol (r = 0.59, p = 0.010) and negatively with fibrinogen (r = -0.53, p = 0.025), CRP (r = -0.52, p = 0.028) and vWF (r = -0.56, p = 0.013)., Conclusions: Increased BF and impaired insulin sensitivity are associated with increased concentrations of cardiovascular risk factors. Leptin seems to be involved in this elevation and emerges as a predictor of circulating fibrinogen concentrations.

The plasma fibrinolytic/proteolytic balance was assessed in 60 stable angina patients who underwent control coronary catheterization and the results were correlated with angiographic findings and control samples (n = 20). The concentrations of t-PA, PAI-1, collagenase (MMP-1), tissue inhibitor of MMP (TIMP-1), plasmin-antiplasmin (PAP) complexes and alpha2-macroglobulin (alpha2-M) were measured in plasma samples. The results showed a significant increase of PAP (p <0.001) and a reduction of alpha2-M (p <0.001) in the group of patients when compared to controls, indicating a degree of fibrinolysis/proteolysis activation. There was no correlation between the different parameters analyzed and the extent of angiographically proven atherosclerosis (one or more stenotic vessels), while the t-PA levels were significantly elevated (p <0.03) in patients with coronary stenosis > or =75% or occlusion. We conclude that there is a disturbance of the plasma fibrinolysis/proteolysis in patients with stable angina not related to the extent of atherosclerosis. The t-PA levels may be a good marker for coronary occlusion in these patients.

Background: The plasminogen activator inhibitor-1 (PAI-1), which modulates fibrinolysis and cell migration, may influence proteolysis and neointimal formation in the arterial wall contributing to restenosis after vascular injury. Antioxidants have been proposed as inhibiting multiple proatherogenic events. We explore the effect of vitamins C and E on PAI-1 expression in an experimental model of angioplasty in hypercholesterolemic pigs., Methods and Results: A total of 44 Yucatan minipigs were divided into three diet groups: a normal-cholesterol (NC), a high-cholesterol (HC), and a high-cholesterol plus vitamins C+E (HCV) group. Balloon injury was induced in the right internal iliac artery 4 weeks after initiation of either dietary regimen, and plasma and tissue samples were taken at different time periods to measure PAI-1 activity and vascular inhibitor expression. The cholesterol-rich diet induced an increased in vascular PAI-1 expression in the intima, media and adventitia which was markedly reduced in the HCV group. After injury, severe structural changes were observed in NC and HC animals associated with increased systemic PAI-1 activity (P<0.001) and local PAI-1 expression being more intense in HC group. Vitamins C and E significantly reduced plasma PAI-1 activity (P=0.018) and attenuated the inhibitor expression as compared with HC., Conclusions: This experimental study in a porcine model of hypercholesterolemia demonstrates that vitamins C and E reduce local and systemic PAI-1 induced after angioplasty as well as the hypercholesterolemia-induced vascular PAI-1.

Heparin and other antithrombotic drugs besides their anticoagulant action could have a profibrinolytic effect. We have analyzed the effect of unfractionated heparin (UFH) and hirudin on PAI-1 gene expression in human umbilical vein endothelial cells (HUVEC). Cells were stimulated with UFH (1 and 10 IU/ml) and hirudin (20 and 100 TIU/ml). Samples were obtained before and 2, 6, and 24 hours after stimulation. mRNA analysis was conducted by reverse transcription followed by polymerase chain reaction, and PAI-1 antigen was determined by ELISA. Addition of UFH (10 IU/ml) to HUVEC resulted in a decrease of PAI-1 mRNA at 6 hours (40% reduction) and 24 hours (60% reduction) and PAI-1 antigen. Hirudin, however, did not modify significantly the PAI-1 mRNA nor the inhibitor secretion. The addition of UFH (10 or 100 IU/ml) to endotoxin-stimulated HUVEC also reduced the increased PAI-1 mRNA and antigen secretion (45%), whereas no effect could be observed with hirudin. Our results suggest that UFH, but not hirudin, by reducing the endothelial expression of PAI-1 might have a profibrinolytic effect.

Background and Objective: Vascular fibrinolysis, a major natural defense mechanism against thrombosis, is a highly regulated process. The aim of this study was to evaluate the effect of endotoxin, tumor necrosis factor-alpha (TNFalpha) and interleukin-1alpha (IL-1alpha), on the fibrinolytic potential of cultured human umbilical vein endothelial cells (HUVEC)., Design and Methods: Samples of stimulated conditioned media were collected over a period of 24 hours to determine: plasminogen activator (PA) and plasminogen activator inhibitor (PAI) activity, PAI-1 mRNA, tissue-type plasminogen activator (t-PA) antigen and urokinase-type plasminogen activator (u-PA) antigen., Results: Similar changes were observed after endotoxin and cytokine stimulation: there was a significant increase of PAI activity (p<0.01), starting at 6 hours, which remained 24 hours after stimulation. PAI-1 mRNA also showed an important rise with these agents, although cytokines induced an earlier and more intense inhibitor response (up to 6-fold increase). PA activity increased significantly at 6 hours (p<0.01) to drop at 24 hours and was mainly related to the presence of u-PA., Interpretation and Conclusions: We conclude that endotoxin,+TNFalpha and IL-1alpha induce profound alterations in the fibrinolytic potential of HUVEC, characterized by an initial rise of activators (u-PA) followed by a strong increase of PAI-1. These changes may be of pathophysiologic significance for thrombosis and inflammatory reactions.

We evaluated the effect of r-hirudin and/or tissue-plasminogen activator (t-PA) in a model of DIC in rabbits induced by i.v. infusion of 100 micrograms/kg/h/6 h endotoxin. Rabbits were treated with saline (endotoxin control group), r-hirudin at 0.3 mg/kg/h/6 h, t-PA at 0.3 mg/kg for 90 min and r-hirudin plus t-PA at the doses described above. The best results were achieved when r-hirudin and t-PA were infused together. This treatment reduced the consumption of platelets and protein C and attenuated the increase of PAI-1 more efficiently than r-hirudin or t-PA alone. r-Hirudin plus t-PA also resulted in the lowest formation of fibrin deposits in the kidneys. Finally, mortality at 24 h dropped from 70% in the endotoxin control group to 40%, 10% and 0% in the t-PA, r-hirudin and r-hirudin plus t-PA groups respectively. None of the t-PA-infused rabbits which had died by 24 h showed macroscopic signs of haemorrhage. r-Hirudin alone was better than t-PA alone, as was shown by fibrin deposits and mortality. We conclude that r-hirudin and t-PA given simultaneously were more efficient than either given alone in this model of DIC. Effective thrombin inhibition, which could influence other pathophysiological mechanisms apart from coagulation, together with the improvement in fibrinolysis, would explain these results.

The effect of low molecular weight heparin (LMWH) with or without antithrombin III (AT III) has been studied in a rabbit model of disseminated intravascular coagulation (DIC) induced by continuous infusion of 100 microg/kg/hr of Escherichia coli endotoxin for 6 hr. LMWH (5 and 10 IU/kg/hr/6 hr), alone or in combination with AT III (20 U/kg/hr/6 hr), or saline were administered simultaneously with endotoxin. Hemostatic markers at 0, 2, and 6 hr as well as kidney fibrin deposits and the mortality rate at 24 hr were determined. Rabbits receiving only endotoxin showed an impairment in hemostasis, as well as high kidney fibrin deposits and a high mortality rate. LMWH alone did not exert any effect. The simultaneous infusion of LMWH and AT III exerted a beneficial effect on the hemostatic markers and reduced the kidney fibrin deposits as well as the mortality rate in a LMWH dose-dependent manner. Fibrinogen and protein C consumption were significantly higher and renal fibrin deposits more intense in the rabbits that had died in the first 24 hr. There was also a significant positive correlation between kidney fibrin deposits and platelets, fibrinogen, and protein C consumption, taking the whole rabbit population. It is concluded that the simultaneous infusion of LMWH and AT III is useful in this DIC model and would make it possible to reduce significantly the AT III doses used when AT III is given alone.

Purpose: Development of monoclonal antibodies capable of inhibiting the specific binding of t-PA to fibrin., Material and Methods: After immunization of Balb/c mice with recombinant t-PA (rt-PA) we selected the monoclonal antibody MA3B5 by its ability to inhibit the binding of t-PA to fibrin, and the MA2C1 devoid of this property. The influence of such antibodies was evaluated on fibrin plates, amidolytic assays and clot lysis assays. Furthermore, their interference with the activator bound to fibrin was assayed with a spectrophotometric solid phase assay (SOFIA)., Results: The results showed that MA3B5 totally inhibited the t-PA induced fibrinolytic activity on fibrin plates, reduced amidolytic activity by 86.5% and inhibited the clot lysis induced by t-PA in a dynamic system. In contrast, the MA2C1 showed no inhibition. By assessing the binding of t-PA to fibrin with the SOFIA assay we could demonstrate that only the MA3B5 reduced significantly (up to 90% with 100 micrograms/mL of antibody) the amount of t-PA bound to fibrin surface., Conclusion: We have purified and characterized a monoclonal antibody which specifically blocks the fibrin binding site of t-PA.