Strategies to control antibiotic resistance: results from a survey in Italian children's hospitals.

BACKGROUND: Antimicrobial stewardship programs and comprehensive infection control programs represent the main strategies to limit the emergence and transmission of multi-drug resistant bacteria in hospital settings. The purpose of this study was to describe strategies implemented in Italian children's hospitals for controlling antibiotic resistance. STUDY DESIGN: Cross sectional multicenter study. METHODS: Four tertiary care Italian children's hospitals were invited to participate in a survey aimed at collecting information on activities implemented as of December 2015 using a self-administered online questionnaire. The questionnaire was divided in three sections focalizing on: i) policies for prevention and control of hospital-acquired infection, ii) prevention and control of multi-drug resistant bacteria, and iii) antibiotic prescribing policies and Antimicrobial stewardship programs. Questionnaires were compiled between May and July 2016. RESULTS: All hospitals had multidisciplinary infection control committee, procedures on hand hygiene, isolation measures, disinfection/sterilization, waste disposal and prevention on infections associated to invasive procedures. All sites screened patients for multi-drug resistant bacteria colonization in selected units, and adopted contact precautions for colonized patients. Screening during hospitalization, or in case of infections in the same ward were not universally implemented. All hospitals had policies on surgical prophylaxis, while policies on medical prophylaxis and treatment of bacterial infections varied among sites. Two sites recommended to review the appropriateness of antibiotic prescribing after 48-72 hours and one recommended de-escalation therapy. CONCLUSIONS: This study highlighted several areas of improvement, such as actions for screening patients in case of occurrence of multi-drug resistant bacteria, antimicrobial stewardship programs and implementation of policies targeting antibiotic prescriptions for therapeutic purposes and medical prophylaxis.

Eighteen-month lamivudine prophylaxis on preventing occult hepatitis B virus infection reactivation in patients with haematological malignancies receiving immunosuppression therapy.

This study evaluated the long-term efficacy and safety of an 18-month lamivudine prophylaxis in 68 HBsAg-negative/anti-HBc-positive patients with oncohaematological disease. All 68 consecutive HBsAg-negative/anti-HBc-positive patients with an oncohaematological disease and naïve for chemotherapy observed from April 2008 to December 2012 at 2 Hematology Units in Naples were treated with lamivudine for 18 months after stopping chemotherapy and monitored for HBsAg at months 1 and 3 during chemotherapy and then every 3 months after its discontinuation. During follow-up, 13 (19.1%) of the 68 patients died of complications related to their oncohaematological disease, and 3 (4%) showed a virological HBV reactivation (retroconversion to HBsAg positivity) 1-7 months after the discontinuation of lamivudine prophylaxis (2 treated for chronic lymphocytic leukaemia and one for Waldenstrom's disease); of these, 2 showed a biochemical reactivation. Comparing the demographic and clinical characteristics of the 3 patients with a virological HBV reactivation to the 65 without, the former were older (median age and range: 67 years [75-78] vs. 61 [24-88]; P = .05) and were less frequently treated for B-cell non-Hodgkin lymphoma (B-NHL) (0 vs. 70.7%, P = .03). In conclusion, a 18 months of lamivudine prophylaxis was effective in preventing HBV reactivation in HBsAg-negative/anti-HBc-positive patients treated for B-NHL. However, in patients with chronic and severe immunodepression, such as those with chronic lymphocytic leukaemia and Waldenstrom's disease, prophylaxis should be continued for an indefinite period.

Sleep-disordered breathing and epicardial adipose tissue in patients with heart failure.

BACKGROUND AND AIMS: Sleep-disordered breathing (SDB) is common in patients with heart failure (HF), contributes to the progression of cardiac disease, and is associated with adverse prognosis. Previous evidence indicates that epicardial adipose tissue (EAT) is independently associated with sleep apnea in obese individuals. We explored the relationship between SDB and EAT in HF patients. METHODS AND RESULTS: EAT thickness was assessed by echocardiography in 66 patients with systolic HF undergoing nocturnal cardiorespiratory monitoring. A significantly higher EAT thickness was found in patients with SDB than in those without SDB (10.7 ± 2.8 mm vs. 8.3 ± 1.8 mm; p = 0.001). Among SDB patients, higher EAT thickness was found in both those with prevalent obstructive sleep apnea (OSA) and those with prevalent central sleep apnea (CSA). Of interest, EAT thickness was significantly higher in CSA than in OSA patients (11.9 ± 2.9 vs. 10.1 ± 2.5 p = 0.022). Circulating plasma norepinephrine levels were higher in CSA than in OSA patients (2.19 ± 1.25 vs. 1.22 ± 0.92 ng/ml, p = 0.019). According to the apnea-hypopnea index (AHI), patients were then stratified in three groups of SDB severity: Group 1, mild SDB; Group 2, moderate SDB; Group 3, severe SDB. EAT thickness progressively and significantly increased from Group 1 to Group 3 (ANOVA p < 0.001). At univariate analysis, only left ventricular ejection fraction and AHI significantly correlated with EAT (p = 0.019 and p < 0.0001, respectively). At multivariate analysis, AHI was the only independent predictor of EAT (ß = 0.552, p < 0.001). CONCLUSIONS: Our results suggest an association between the presence and severity of sleep apneas and cardiac visceral adiposity in HF patients.

Efficacy and safety of glucagon-like peptide-1 agonists on macrovascular and microvascular events in type 2 diabetes mellitus: A meta-analysis.

AIMS: Glucagon-like peptide-1 (GLP-1) agonists improve glycaemic control in type 2 diabetes mellitus (DM). Outcome trials investigating macro and microvascular effects of GLP-1 agonists reported conflicting results. The aim of this study was to assess, in a meta-analysis, the effects of GLP-1 agonists on mortality, major nonfatal cardiovascular (CV) events, renal and retinal events. DATA SYNTHESIS: MEDLINE, Cochrane, ISI Web of Science, SCOPUS and ClinicalTrial.gov databases were searched for articles published until June 2017. Randomized trials enrolling more than 200 patients, comparing GLP-1 versus placebo or active treatments in patients with DM, and assessing outcomes among all-cause death, CV death, MI, stroke, HF, diabetic retinopathy and nephropathy were included. 77 randomized trials enrolling 60,434 patients were included. Compared to control, treatment with GLP-1 significantly reduced the risk of all-cause death (RR: 0.888; CI: 0.804-0.979; p = 0.018) and the risk of CV death (RR: 0.858; CI: 0.757-0.973; p = 0.017). GLP-1 agonists did not affect the risk of MI (RR: 0.917; CI: 0.830-1.014; p = 0.092) as well as the risk of stroke (RR: 0.882; CI: 0.759-1.023; p = 0.097), HF (RR: 0.967; CI: 0.803-1.165; p = 0.725), retinopathy (RR: 1.000; CI: 0.807-1.238; p = 0.997) and nephropathy (RR: 0.866; CI: 0.625-1.199; p = 0.385). CONCLUSIONS: Treatment with GLP-1 agonists in DM patients is associated with a significant reduction of all cause and CV mortality.

Vitamin D deficiency and clinical outcome in patients with chronic heart failure: A review.

AIM: The aim of this review was to summarize evidence on the role of Vitamin D deficiency in heart failure (HF), from pathophysiological mechanisms to clinical effects of Vitamin D supplementation. DATA SYNTHESIS: Chronic HF secondary to left ventricular (LV) systolic dysfunction is a growing health problem, still associated with poor clinical outcome. In recent years, experimental and epidemiological evidence focused on the role of Vitamin D in HF. Cross sectional studies demonstrated that prevalence of HF is increased in patients with Vitamin D deficiency or parathyroid hormone (PTH) plasma level increase, whereas longitudinal studies showed enhanced risk of developing new HF in patients with Vitamin D deficiency. In addition, in patients with established HF, low plasma levels of Vitamin D are associated with worsening clinical outcome. Yet, clinical studies did not definitively demonstrate a benefit of Vitamin D supplementation for preventing HF or ameliorating clinical outcome in patients with established HF. CONCLUSIONS: Despite convincing experimental and epidemiological data, treatment with Vitamin D supplementation did not show clear evidence of benefit for preventing HF or influencing its clinical course. Ongoing clinical studies will hopefully shed lights on the effects of Vitamin D supplementation on clinical endpoints along the spectrum of HF.

FXR activation improves myocardial fatty acid metabolism in a rodent model of obesity-driven cardiotoxicity.

BACKGROUND AND AIMS: Obesity-driven lipotoxicity is a risk factors for cardiovascular disease. The Farnesoid X Receptor (FXR) is a bile acids sensor and member of the nuclear receptor superfamily. Activation of FXR lowers plasma triacylglycerols and glucose levels through a mechanism that involves both the repression of key regulatory genes in the liver and the modulation of insulin sensitivity in peripheral tissues. In the present study we have investigated whether administering obese (fa/fa) Zucker rats, a genetic model of obesity associated with dyslipidemia and insulin resistance, with an FXR ligand protects against lipid-induced cardiomyopathy. METHODS AND RESULTS: FXR is expressed in neonatal cardiomyocytes and the treatment with FXR agonists, chenodeoxycholic acid (CDCA), and GW4064, increased the mRNA expression of FXR and its canonical target gene, the small heterodimer partner (SHP), as well as proliferator-activated receptor alpha PPARα, acyl-CoA oxidase (AOX) and pyruvate dehydrogenase kinase (PDK-4). Feeding obese fa/fa rats with CDCA, 12 weeks, reduced hyperinsulinemia and hyperlipidaemia. The histological-pathological analysis of hearts demonstrated that treatment with the FXR ligand reduced lipid heart content decreased the rate of apoptosis, fibrosis scores and restored heart insulin signalling. Chronic CDCA administration, in the heart, induced PPARα and PPARα-regulated genes involved in ß-oxidation. CONCLUSION: FXR agonism exerts beneficial effects in a genetic model of lipid-induced cardiomyopathy. The striking benefit of this therapy on cardiac function in this model warrants an effort to determine whether a counterpart of this activity translates in human settings.

Changes in serum uric acid levels and cardiovascular events: a meta-analysis.

BACKGROUND AND AIMS: The association between serum uric acid (SUA) levels and cardiovascular (CV) risk or all-cause death has been repeatedly reported. However, it has not been assessed whether reduction of SUA levels is associated with reduced CV risk. The aim of the current study was to evaluate the relationship between changes of SUA levels and CV events as well as all-cause death. METHODS AND RESULTS: Randomised trials reporting SUA at baseline and at the end of follow-up and clinical end-points (all-cause death, myocardial infarction (MI), stroke, heart failure (HF) and CV death) were included in the study. Meta-regression analysis was performed to test the relationship between SUA changes and clinical end-points. Eleven trials enrolling 21,373 participants followed up for 2.02 ± 1.76 years and reporting 4533 events were included. In meta-regression analysis, no relationship between SUA changes from baseline to end of follow-up and the composite outcome including CV death, stroke, MI and HF was found (change in Tau(2) (t) = -0.64; p Tau (p) = 0.541). Similarly, no relationship was found between SUA changes and single components of the composite outcome (MI: t = -0.83; p = 0.493; stroke: t = 0.46; p = 0.667; HF: t = 2.44; p = 0.162; CV death: t = -0.54; p = 0.614) and all-cause death (t = -0.72; p = 0.496). Results were confirmed by sensitivity analysis. No heterogeneity among studies or publication bias was detected. CONCLUSIONS: Changes in SUA levels observed during pharmacologic treatments do not predict the risk of all-cause death or CV events. As SUA levels are associated with increased CV risk, additional studies with direct xanthine-oxidase inhibitors are requested.

Cerebrospinal fluid beta-glucocerebrosidase activity is reduced in Dementia with Lewy Bodies.

The autophagy-lysosomal degradation pathway plays a role in the onset and progression of neurodegenerative diseases. Clinical and genetic studies indicate that mutations of beta-glucocerebrosidase represent genetic risk factors for synucleinopathies, including Parkinson's Disease (PD) and Dementia with Lewy Bodies (DLB). We recently found a decreased activity of lysosomal hydrolases, namely beta-glucocerebrosidase, in cerebrospinal fluid of PD patients. We have thus measured the activity of these enzymes - alpha-mannosidase (EC 3.2.1.24), beta-mannosidase (EC 3.2.1.25), beta-glucocerebrosidase (EC 3.2.1.45), beta-galactosidase (EC 3.2.1.23) and beta-hexosaminidase (EC 3.2.1.52) - in cerebrospinal fluid of patients suffering from DLB, Alzheimer's Disease (AD), Fronto-Temporal Dementia (FTD) and controls. Alpha-mannosidase activity showed a marked decrease across all the pathological groups as compared to controls. Conversely, beta-glucocerebrosidase activity was selectively reduced in DLB, further suggesting that this enzyme might specifically be impaired in synucleinopathies.

Leptin induces tissue factor expression in human peripheral blood mononuclear cells: a possible link between obesity and cardiovascular risk?

BACKGROUND: Obesity is a major modifiable risk factor for cardiovascular disease. Leptin, the hormone synthesized and released primarily by adipose tissue and found increased in obese individuals, has been implicated in the regulation of inflammation and arterial and venous thrombosis. OBJECTIVE: To investigate the role of tissue factor (TF), the pivotal agonist of the clotting cascade, as a link between obesity and cardiovascular disease. METHODS AND RESULTS: In 15 obese patients, plasma levels of leptin and TF as well as TF expression in resting and endotoxin-stimulated mononuclear leukocytes (MN) were increased when compared with healthy donors. In a selected sample of obese patients, loss of body weight led to decreased circulating leptin levels, accompanied by a reduction in plasma TF as well as in TF expression, both in resting and endotoxin-stimulated MN. In subsequent in vitro experiments, leptin was incubated with MN from healthy subjects. Leptin induced TF activity and antigen in a dose-dependent fashion, as assessed by clotting assay and ELISA, respectively. Increased migration of c-Rel/p65 into the nucleus, as determined by EMSA, and development of TF mRNA in monocytes, as assessed by RT-PCR, were observed. Experiments with mitogen-activated protein kinase (MAPK) inhibitors, indicated the involvement of p38 and ERK1/2 pathways. CONCLUSIONS: The presence of TF-expressing MN in blood from obese subjects and the in vitro induction of TF by pharmacologic concentrations of leptin in MN from healthy subjects suggest that TF expression by leptin-stimulated monocytes may contribute to the cardiovascular risk associated with obesity.

Persistent platelet activation in patients with type 2 diabetes treated with low doses of aspirin.

BACKGROUND: The percentage of diabetic patients who do not benefit from the protective effect of aspirin is larger than in other populations at cardiovascular risk. OBJECTIVE: We compared the ability of aspirin to suppress TxA2 and platelet activation in vivo, in type-2 diabetics vs. high-risk non-diabetic patients. METHODS: Urinary 11-dehydro-TXB2, plasma sCD40 L, and sP-selectin were measured, together with indices of low-grade inflammation, glycemic control, and lipid profile, in 82 patients with type-2 diabetes and 39 without diabetes, treated with low doses of aspirin. RESULTS: Urinary 11-dehydro-TxB2, plasma sCD40L and sP-selectin were significantly higher in diabetics than in controls: [38.9 (27.8-63.3) vs. 28.5 (22.5-43.9) ng mmol(-1) of creatinine, P = 0.02], [1.06 (0.42-3.06) vs. 0.35 (0.22-0.95) ng mL(-1); P = 0.0001], [37.0 (16.8-85.6) vs. 20.0 (11.2-35.6) ng mL(-1), P = 0.0001], respectively. The proportion of individuals with diabetes increased across quartiles of 11-dehydro-TxB2, sCD40L, and sP-selectin, with the highest quartiles of 11-dehydro-TxB2, sCD40L and sP-selectin, including 66%, 93.3%, and 93.3% of individuals with diabetes. Markers of platelet activation positively correlated with indices of glycemic control but not with markers of low-grade inflammation. CONCLUSIONS: Platelet dysfunction associated with insufficient glycemic control, may mediate persistent platelet activation under aspirin treatment.

Polymorphisms of the interleukin-1beta gene affect the risk of myocardial infarction and ischemic stroke at young age and the response of mononuclear cells to stimulation in vitro.

OBJECTIVE: To investigate the role of interleukin-1beta (IL-1beta) gene polymorphisms as a link between inflammation, coagulation, and risk of ischemic vascular disease at young age. METHODS AND RESULTS: A total of 406 patients with myocardial infarction (MI) at young age, frequency-matched for age, sex, and recruitment center, with 419 healthy population-based controls and 134 patients with ischemic stroke at young age, matched by age and sex, with 134 healthy population-based controls, were studied. Subjects carrying the TT genotype of the -511C/T IL-1beta polymorphism showed a decreased risk of MI (odds ratio [OR], 0.36; 95% CI, 0.20 to 0.64) and stroke (OR, 0.32; 95% CI, 0.13 to 0.81) after adjustment for conventional risk factors. In both studies, the T allele showed a codominant effect (P=0.0020 in MI; P=0.021 in stroke). Mononuclear cells from volunteers carrying the T allele showed a decreased release of IL-1beta and a decreased expression of tissue factor after stimulation with lipopolysaccharide compared with CC homozygotes. The presence of a monoclonal antibody against IL-1beta during cell stimulation resulted in a marked reduction of tissue factor activity expression. CONCLUSIONS: -511C/T IL-1beta gene polymorphism affects the risk of MI and ischemic stroke at young age and the response of mononuclear cells to inflammatory stimulation.

Roflumilast inhibits leukocyte-platelet interactions and prevents the prothrombotic functions of polymorphonuclear leukocytes and monocytes.

UNLABELLED: ESSENTIALS: Thrombosis is a major comorbidity in patients with chronic obstructive pulmonary disease (COPD). Roflumilast is a selective phosphodiesterase type-4 (PDE4) inhibitor approved for treatment of severe COPD. PDE4 blockade by roflumilast inhibits prothrombotic functions of neutrophils and monocytes. PDE4 inhibitors may reduce thrombotic risk in COPD as well as in other vascular diseases. BACKGROUND: Roflumilast, an oral selective phosphodiesterase type 4 inhibitor, is approved for the treatment of severe chronic obstructive pulmonary disease (COPD). A recent meta-analysis of trials on COPD revealed that treatment with roflumilast was associated with a significant reduction in the rate of major cardiovascular events. The mechanisms of this effect remain unknown. OBJECTIVES: We tested the hypothesis that roflumilast N-oxide (RNO), the active metabolite of roflumilast, curbs the molecular mechanisms required for leukocyte-platelet (PLT) interactions and prevents the prothrombotic functions of polymorphonuclear leukocytes (PMNs) and monocytes (MNs). METHODS: Using well-characterized in vitro models, we analysed the effects of RNO on: (i) PMN adhesiveness; (ii) the release of neutrophil extracellular traps (NETs); and (iii) tissue factor expression in MNs. Key biochemical events underlying the inhibitory effects of RNO were defined. RESULTS AND CONCLUSIONS: In PMNs, RNO prevented phosphoinositide 3-kinase (PI3K)-dependent phosphorylation of Akt on Ser473, and Src family kinase (SFK)-mediated Pyk2 phosphorylation on Tyr579-580, while inducing protein kinase A-mediated phosphorylation of C-terminal Src kinase, the major negative regulator of SFKs. Modulation of these signaling pathways by RNO resulted in a significant impairment of PMN adhesion to activated PLTs or human umbilical vein endothelial cells, mainly mediated by inhibition of the adhesive function of Mac-1. Moreover RNO curbed SFK/PI3K-mediated NET release by PMNs adherent on fibrinogen-coated surfaces. In MNs interacting with activated PLTs, RNO curbed PI3K-mediated expression of tissue factor. The efficacy of RNO was significantly potentiated by formoterol, a long acting ß-adrenergic receptor agonist. This study reveals novel antithrombotic activities by which roflumilast may exert protective effects against cardiovascular comorbodities in COPD.

Inhibitors of acyl CoA:cholesterol acyltransferase.

Conformational restriction of previously disclosed acyclic (diphenylethyl)diphenylacetamides led to the discovery of several potent inhibitors of acyl CoA:cholesterol acyltransferase (ACAT). cis-[2-(4-Hydroxyphenyl)-1-indanyl]diphenylacetamide (4a) was the most potent ACAT inhibitor identified (IC50 = 0.04 microM in an in vitro rat hepatic microsomal ACAT assay, ED50 = 0.72 mg/kg/day in cholesterol-fed hamster.

Effect of lipid-lowering treatment on factor VII profile in hyperlipidemic patients.

A link has been suggested between blood lipids and hemostatic activation. Factor VII (FVII) is a coagulation factor which plays a pivotal role in fibrin generation and thrombus formation. Clinical trials have demonstrated that inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase greatly reduce cardiovascular events in patients with and without coronary artery disease but few data, at this time, are available on the effects of lipid-lowering treatment on factor VII levels. We studied thirty-six IIA and IIB type hyperlipidemic patients who, after a preliminary period of lipid-lowering diet, added atorvastatin (20 mg/daily) or continued dietary treatment alone until they achieved LDL-C recommended levels (<4 mmol/L). Four to six weeks of lipid lowering treatment with diet plus atorvastatin, produced a significant reduction in FVII coagulant activity (FVIIc) and antigen (FVIIAg). No significant changes were observed in activated FVII (FVIIa). The lipid-lowering treatment with diet alone induced an improved lipid pattern, but no significant changes in FVII profile. Our study suggests a significant effect of lipid-lowering treatment on FVII levels. A possibile nonlipid mechanism that modifies FVII pathway may be suggested.

Neutrophil derived cathepsin G induces potentially thrombogenic changes in human endothelial cells: a scanning electron microscopy study in static and dynamic conditions.

Activated neutrophils may promote thrombus formation by releasing proteases which may activate platelets, impair the fibrinolytic balance and injure the endothelial monolayer. We have investigated the morphological correlates of damage induced by activated neutrophils on the vascular wall, in particular the vascular injury induced by released cathepsin G in both static and dynamic conditions. Human umbilical vein endothelial cells were studied both in a cell culture system and in a model of perfused umbilical veins. At scanning electron microscopy, progressive alterations of the cell monolayer resulted in cell contraction, disruption of the intercellular contacts, formation of gaps and cell detachment. Contraction was associated with shape change of the endothelial cells, that appeared star-like, while the underlying extracellular matrix, a potentially thrombogenic surface, was exposed. Comparable cellular response was observed in an "in vivo" model of perfused rat arterial segment. Interestingly, cathepsin G was active at lower concentrations in perfused vessels than in culture systems. Restoration of blood flow in the arterial segment previously damaged by cathepsin G caused adhesion and spreading of platelets on the surface of the exposed extracellular matrix. The subsequent deposition of a fibrin network among adherent platelets, could be at least partially ascribed to the inhibition by cathepsin G of the vascular fibrinolytic potential. This study supports the suggestion that the release of cathepsin G by activated neutrophils, f.i. during inflammation, may contribute to thrombus formation by inducing extensive vascular damage.

4G/5G promoter PAI-1 gene polymorphism is associated with plasmatic PAI-1 activity in Italians: a model of gene-environment interaction.

The PAI-1 gene promoter 4G/5G polymorphism was found to be associated with plasma PAI-1 activity in Northern and Central Europe populations, but no data are available on the association between this polymorphism and PAI-1 levels in Southern Europe countries (such as Italy) where the incidence of ischemic disorders is lower. This study shows that among populations with different incidence of atherothrombotic disorders the 4G/5G PAI-1 gene promoter polymorphism has the same importance in the regulation of plasma PAI-1 activity. Moreover, we have analysed some gene-environmental interactions: the correlation between PAI-1 and cholesterol in non dyslipidemic subjects and the correlation between PAI-1 activity and tryglicerides in dyslipidemic subjects differed according to the 4G/5G genotype class. Thus, our findings suggest that, among subjects with or without metabolic disorders such as dyslipidemia, completely different gene-environment interactions may occur.

Genetic modulation of coagulation factor VII plasma levels: contribution of different polymorphisms and gender-related effects.

We studied the relationships among different polymorphisms of FVII gene in determining FVII levels, in a sample of 335 male and female Italian volunteers. The hypervariable region 4 (HVR4), the promoter decanucleotide insertion (-323 0/10 bp) and the R353Q polymorphisms of FVII gene were evaluated. The association of HVR4 or -323 0/10 bp polymorphism with plasma FVII levels differed between gender (Interaction term: p = 0.02 and p = 0.03, respectively), showing stronger effect in males than in females. In males, the R353Q and the HVR4 polymorphisms showed an incremental influence on FVII variance (F = 8.9, p <0.001 and F = 4.4, p = 0.01, respectively). Moreover, the effects of Q and 10 bp alleles on the reduction of FVII activity levels were significantly potentiated by the presence of H7 allele of HVR4 (Interaction term p = 0.03 for R353Q*HVR4 and p = 0.03 for -323 0/10 bp*HVR4). In conclusion, the effect of FVII polymorphisms on FVII levels was gender dependent and derived from a complex interaction among them. The HVR4 polymorphism seems to add an independent, albeit small, contribution to the regulation of FVII plasma levels.

Experimental arterial thrombosis in genetically or diet induced hyperlipidemia in rats--role of vitamin K-dependent clotting factors and prevention by low-intensity oral anticoagulation.

To investigate the relationship among lipids, coagulation and thrombosis in the absence of atherosclerosis, spontaneous or dietary-induced hyperlipidemic (FHL) rats were studied. FHL showed higher levels of coagulation factors VII, IX, X, VIII and XII and a shortening of the occlusion time (OT) of an artificial arterial prosthesis as compared with normolipidemic (FNL) animals. Damage of abdominal aorta of FHL was followed by increased fibrin deposition in the vascular intima as compared to FNL. After 5 months of cholesterol-rich diet FNL showed increased cholesterol, triglycerides and factor II, VII, IX, X, XII levels. A significant shortening of the OT and increased fibrin deposition was also observed. Two-month diet withdrawal restored the initial condition. Warfarin treatment, at a dose decreasing vitamin K-dependent factor to levels found in FNL, prolonged the OT and reduced fibrin deposition, without modifying F XII or changing lipid profile. An increase in the activated form of F VII was observed. In contrast, no difference was found in F VII clearance. High lipid levels favour the process of thrombus formation by increasing the activation of vitamin K-dependent coagulation factors. Low-dose warfarin treatment reverts the prothrombotic effect of hyperlipidemia.

Effect of aspirin on the fibrinolytic response in perfused rat hindquarters.

The role of aspirin on tissue plasminogen activator (t-PA) release was studied in rats after experimental venous occlusion. For this purpose, we developed a new experimental model which combines a vascular perfusion system (isolated rat hindquarters) with vascular stimulation, namely the application of venous stasis. Application of venous stasis for 30 min induced the release of t-PA from the vascular endothelium into the perfusate (from 0.19 +/- 0.05 to 0.39 +/- 0.05 UI/ml), reaching a peak 90 s after reperfusion. Aspirin administered to rats 60 min before the experiments (100 mg/kg i.v.), or dissolved in Tyrode solution (100 microM), suppressed 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) synthesis (0.38 +/- 0.09 in control and < 0.01 and 0.15 +/- 0.09 ng/ml, respectively, in aspirin-treated groups) but did not prevent the increase in fibrinolytic activity after venous occlusion (from 0.20 +/- 0.04 to 0.38 +/- 0.06 and from 0.07 +/- 0.03 to 0.27 +/- 0.03 IU/ml, respectively, in the aspirin-treated group). Our results suggest that the increase in fibrinolytic activity after experimental venous occlusion in isolated rat hindlegs is modulated by mechanism(s) other than the cyclooxygenase pathway in the vascular wall.

The decanucleotide insertion/deletion polymorphism in the promoter region of the coagulation factor VII gene and the risk of familial myocardial infarction.

Recently, an association has been found between factor VII polymorphisms and the risk of familial myocardial infarction. To obtain a thorough evaluation of the influence of factor VII gene on the risk of myocardial infarction, we extended our analysis to the role of a decanucleotide insertion/deletion functional polymorphism (-323 0/10-bp) in the promoter region of factor VII and to possible interactions with the HVR4 intron polymorphism. We performed a case-control study of 176 patients with myocardial infarction, over 45 years, who had a familial history of arterial thrombosis and 227 control subjects without a personal or family history of cardiovascular disease. The frequency of the rare allele of 10 bp was lower in cases (0.14 95% CI, 0.10-0.17) than in controls (0.19 95% CI, 0.16-0.23; chi(2)=4.7, p=0.03). Allowing for Hardy-Weinberg equilibrium in controls and testing for association under restricted maximisation, there was a significant difference in genotype frequency between cases and controls (p=0.02). Carriers of the 10-bp allele had an odds ratio for myocardial infarction of 0.65 (95% CI, 0.37-1.12), in multivariate logistic regression analysis. Combination analysis of -323 0/10-bp and HVR4 polymorphisms shows half reduction in the risk of myocardial infarction in comparison with the reference group for all the other groups, suggesting that there was no additivity between the effect of the 10-bp and the H7 alleles. Our findings suggest that the promoter polymorphism of factor VII gene may influence the risk of familial myocardial infarction.