Fibrinogen: an important risk factor for atherothrombotic diseases

Antibacterial properties of Allium sativum L. against the most emerging multidrug-resistant bacteria and its synergy with antibiotics

Garlic has long been known as the most effective plant species in treatment of bacterial infections. Considering the vast potential of garlic as a source of antimicrobial drugs, this study is aimed to evaluate the antibacterial activity of Allium sativum extracts and their interactions with selected antibiotics against drug-sensitive and multidrug-resistant isolates of emerging bacterial pathogens that are frequently found in healthcare settings. As shown by the in vitro data obtained in this study, the whole Allium sativum extract inhibited the growth of a broad range of bacteria, including multidrug-resistant strains with bactericidal or bacteriostatic effects. Depending on the organism, the susceptibility to fresh garlic extract was comparable to the conventional antibiotic gentamycin. Since the combinations of fresh garlic extract with gentamycin and ciprofloxacin inhibited both the drug sensitive and MDR bacteria, in most cases showing a synergistic or insignificant relationship, the potential use of such combinations may be beneficial, especially in inhibiting drug-resistant pathogens. The study results indicate the possibility of using garlic as e.g. a supplement used during antibiotic therapy, which may increase the effectiveness of gentamicin and ciprofloxacin.

iTRAQ-Based Quantitative Proteomics Analysis of the Protective Effect of Yinchenwuling Powder on Hyperlipidemic Rats

Yinchenwuling powder (YCL) is an effective traditional Chinese medicine formula to modulate lipid levels. In this study, we established hyperlipidemic rat models and treated them with YCL. The serum concentrations of lipid, malondialdehyde (MDA), endothelin-1 (ET-1), and calcitonin gene-related peptide (CGRP) were measured. Adventitia-free vascular proteins between hyperlipidemic rats and YCL-treated rats were identified using iTRAQ-based quantitative proteomics research approach. Proteins with 1.3-fold difference were analyzed through bioinformatics, and proteomic results were verified by Western blot. The results showed that the serum levels of TC, TG, LDL-C, ET-1, and MDA were significantly decreased, whereas the HDL-C and CGRP levels were significantly increased in the YCL-treated group. Proteomics technology identified 4,382 proteins, and 15 proteins were selected on the basis of their expression levels and bioinformatics. Of these proteins, 2 (Adipoq and Gsta1) were upregulated and 13 (C3, C4, C6, Cfh, Cfp, C8g, C8b, Lgals1, Fndc1, Fgb, Fgg, Kng1, and ApoH) were downregulated in the YCL-treated rats. Their functions were related to immunity, inflammation, coagulation and hemostasis, oxidation and antioxidation, and lipid metabolism and transport. The validated results of ApoH were consistent with the proteomics results. This study enhanced our understanding on the therapeutic effects and mechanism of YCL on hyperlipidemia.

Blood flow in the internal carotid artery with common carotid artery-occluding lesions in Takayasu arteritis

OBJECTIVE

The purpose of this study was to investigate carotid artery hemodynamics and blood flow involving external carotid artery (ECA) and internal carotid artery (ICA) patency in patients with Takayasu arteritis (TA).

METHODS

The common carotid artery (CCA), ECA, ICA, and vertebral artery (VA) were examined in 19 patients with TA involving ECA and ICA patency and in 19 healthy control participants. Bilateral carotid sonographic studies were performed with the use of 5- to 8-MHz linear transducers.

RESULTS

Patency of the ECA and ICA was noted in 14 bilateral, 2 right-sided, and 3 left-sided CCA lesions. Flow in the ECA was retrograde, whereas flow in the ICA was directed cephalad and showed a low-frequency, damped waveform or even a veinlike waveform. The peak systolic velocity (PSV) of the ICA in the patients was significantly lower than that in the control participants (P < .001). A good correlation was observed in the PSV between the ECA and ICA (r = 0.77). The VA displayed normally directed flow, a significantly larger diameter, and a higher flow velocity (P < .001).

CONCLUSIONS

Color duplex sonography can identify special features of TA with CCA-occluding lesions and permit quantification of carotid artery flow velocities and VA diameters both efficiently and practically.

Quality of life of patients with Takayasu's arteritis

OBJECTIVE

Takayasu's arteritis (TA) is a chronic immune vasculitis that causes inflammation of the aorta and its branches and is clinically characterized by exacerbations and remissions. This study examined the quality of life (QoL) of patients with TA using the Medical Outcomes Study Short Form 36 (SF-36) Health Survey, a validated health related QoL questionnaire.

METHODS

Questionnaires that included the SF-36 and demographic related variables were mailed to 392 patients enrolled in the Takayasu's Arteritis Research Association. Raw SF-36 scores, as well as Physical Health Summary (PHS) and Mental Health Summary (MHS) scores, were calculated according to standard protocols. Data were analyzed for predictors of superior QoL using univariate and stepwise logistic regression analysis. SF-36 scores were also compared with those of other chronic diseases associated with peripheral vascular disease (PVD) published in the literature. Results are reported as mean +/- standard error of the mean.

RESULTS

A total of 158 patients (144 women, 14 men) with average age of 42.2 +/- 1.1 years responded to the questionnaire. Mean onset of symptoms occurred at 30.5 +/- 1.2 years, with a mean age at diagnosis of 34.7 +/- 1.2, and a median of four doctors were seen before diagnosis. The group underwent 299 TA-related surgical procedures (1.9 +/- 0.3), including coronary (38%), carotid (35%), upper extremity (30%), and lower extremity (26%) revascularization. PHS and MHS summary scores (39.2 +/- 1.0 and 44.5 +/- 1.0, respectively) were worse than mean scores for an age-matched healthy population as well as nationally reported scores for diabetes mellitus, hypertension, and coronary artery disease (all P < .0001). Multivariate predictors of better physical QoL were younger age (P = .003) and remission of the disease (P = .0002). The use of immunomodulating medications was associated with inferior physical QoL (P = .02). The sole predictor of better mental QoL was remission of disease (P = .002).

CONCLUSION

TA is a rare disease with profound consequences on QoL. Scores for physical and mental health are worse compared with many other chronic diseases associated with PVD. Superior physical QoL is seen in younger patients, whereas inferior physical QoL is encountered in those who take immunomodulating medications. Because the only factor to influence positively both physical and mental QoL is disease remission, every effort should be directed to attenuate disease activity.

Japanese collaborative study for fibrinogen assay: variability of the fibrinogen assay between different laboratories does not improve when a common calibrator is used

Several national and local external quality assurance schemes have been developed to improve the plasma fibrinogen assay in Japan over the past 30 years. Now most commercial calibrant plasma may be calibrated against an International Standard preparation, in order to achieve agreement of results obtained by different laboratories. However, we have never achieved satisfactory results, according to an external quality control survey regarding the fibrinogen assay. Therefore, we distributed two kinds of fibrinogen standards to be used as common calibrators, along with three plasma samples, among 183 general laboratories in Japan. The results of this collaborative study showed that the assigned value for the commercially available calibrators remained problematic. Furthermore, it was concluded that the between-laboratory variability could not be improved beyond a certain degree of standardization, even if a common calibrator was used for the Clauss-derived assay carried out by an automatic coagulometer.

Age-dependent relation of serum sialic acid concentration to aortic pulse wave velocity in type 2 diabetes

OBJECTIVE

The purpose of this study was to determine whether age affects the significance of serum sialic acid concentration as a marker of atherosclerosis in patients with diabetes.

METHODS

In this cross-sectional study, we investigated the relationship of serum sialic acid concentration to aortic pulse wave velocity (a-PWV) and the effects of age on this relationship in patients with type 2 diabetes.

RESULTS

In the elderly (70 years or over) diabetic patients, a-PWV showed a significant positive correlation with serum sialic acid. This relationship was also significant after adjustment for age, duration of diabetes, body mass index, systolic blood pressure, LDL cholesterol, HDL cholesterol and fibrinogen levels. In elderly diabetic patients, a-PWV also showed a significant positive correlation with age and duration of diabetes and a significant negative correlation with serum HDL cholesterol level. On the other hand, in the younger (31-60 years) diabetic patients, there was no significant correlation between serum sialic acid level and a-PWV, while a-PWV showed significant positive correlations with age, duration of diabetes and plasma fibrinogen level.

CONCLUSIONS

Serum sialic acid level reflects atherosclerosis in elderly diabetic patients but not in younger diabetic patients. This may explain recent controversial findings regarding the relationship between serum sialic acid level and incidence of coronary heart disease in diabetes.

Secondary prevention with folic acid: effects on clinical outcomes

OBJECTIVES

We sought to conduct a randomized trial with folic acid 0.5 mg/day in a patient population with stable coronary artery disease (CAD).

BACKGROUND

Folic acid has favorable effects on vascular endothelium and lowers plasma homocysteine levels. In addition, homocysteine appears to be an independent risk factor for atherosclerotic disease. However, the value of folic acid in secondary prevention had seldom been tested.

METHODS

In this open-label study, 593 patients were included; 300 were randomized to folic acid and 293 served as controls. Mean follow-up time was 24 months. At baseline all patients had been on statin therapy for a mean of 3.2 years.

RESULTS

In patients treated with folic acid, plasma homocysteine levels decreased by 18%, from 12.0 +/- 4.8 to 9.4 +/- 3.5 micromol/l, whereas these levels remained unaffected in the control group (p < 0.001 between groups). The primary end point (all-cause mortality and a composite of vascular events) was encountered in 31 (10.3%) patients in the folic acid group and in 28 (9.6%) patients in the control group (relative risk 1.05; 95% confidence interval: 0.63 to 1.75). In a multifactorial survival model with adjustments for clinical factors, the most predictive laboratory parameters were, in order of significance, levels of creatinine clearance, plasma fibrinogen, and homocysteine.

CONCLUSIONS

Within two years, folic acid does not seem to reduce clinical end points in patients with stable coronary artery disease (CAD) while on statin treatment. Homocysteine might therefore merely be a modifiable marker of disease. Thus, low-dose folic acid supplementation should be treated with reservation, until more trial outcomes become available.

Plasma fibrinogen as a predictor of total and cause-specific mortality in elderly Japanese-American men

The relation between plasma fibrinogen and total and cause-specific mortality was investigated in a cohort of 3571 Japanese-American men aged 71 to 93 years during a median follow-up of 4.4 years. There were a total of 728 deaths, of which 37% were accounted for by cardiovascular disease and 27% by cancer. The age-adjusted relative risk (RR) for total mortality in the top quintile of fibrinogen (>3.51 g/L) compared with the bottom quintile (<2.57 g/L) was 4.3 (P<0.0001) in the first year of follow-up. RR was reduced to 1.7 in the second year but remained significantly and slightly increased in subsequent years. After adjustment for age and confounding risk factors, the RRs (and 95% confidence intervals) associated with a 1-SD increment of fibrinogen (0.64 g/L) for all-cause, cardiovascular disease, cancer, and other-cause mortality were 1.3 (1.2 to 1.4), 1.2 (1.1 to 1.4), 1.3 (1.2 to 1.5), and 1.3 (1.2 to 1.5), respectively. Preexisting diseases did not influence the significant association of fibrinogen with mortality. There was a significant interaction of fibrinogen with white blood cell count but not with cigarette smoking. We conclude that plasma fibrinogen is an independent risk factor for mortality from a broad spectrum of diseases in elderly men and that this universal effect of fibrinogen on mortality may be mediated partly through inflammation.

Elevation of fibrinogen and thrombin-antithrombin III complex levels of type 2 diabetes mellitus patients with retinopathy and nephropathy

Diabetes is associated with a hypercoagulable state. Blood hypercoagulability may accelerate atherosclerosis and the diabetic microvascular complications. Thrombin-antithrombin III complex (TAT) and fibrinogen levels are parameters of coagulation and fibrinolysis. In the present study, we examined the risk factors for the diabetic microangiopathy including TAT and fibrinogen levels. To investigate the relationship between the clinical parameters and microangiopathy in type 2 diabetic patients, the clinical parameters of subjects with microangiopathy were compared with those of subjects without microangiopathy. The clinical parameters were as follows: age at examination, duration of diabetes, fasting plasma glucose (FPG) level, HbA(1C) level, insulin level, TAT level, fibrinogen level, lipoprotein (a) (Lp(a)) level, total cholesterol level, triglyceride level, HDL cholesterol level and existence of hypertension. The plasma TAT and fibrinogen levels were significantly higher in patients with retinopathy or nephropathy than in patients without these complications. Moreover, fibrinogen levels of patients with microalbuminuria or background retinopathy were significantly higher than those of patients with normoalbuminuria or no retinopathy. The duration of diabetes was significantly longer in patients with any microangiopathy than in patients without it. Multiple regression analyses showed that duration and fibrinogen level were independent factors associated with the existence of retinopathy or nephropathy. Our data show that the disorder of coagulation and fibrinolysis is significantly associated with diabetic retinopathy and nephropathy and exists at the early stage of microangiopathy.

Resistance of gammaA/gamma' fibrin clots to fibrinolysis

Elevated plasma fibrinogen levels are a major risk factor for thrombosis. This report shows two mechanisms by which fibrinogen can affect the fibrinolysis rate in vitro and thus may lead to thrombosis. First, the lysis rate of fibrin decreases as the initial concentration of fibrinogen increases. Second, a minor variant form of fibrinogen decreases the rate of fibrinolysis. This variant, gammaA/gamma' fibrinogen, has one altered gamma chain and is known to bind to factor XIII zymogen. In a fibrinolysis assay containing purified thrombin, fibrinogen, tissue-type plasminogen activator, and plasminogen, clots from gammaA/gammaA and gammaA/gamma' fibrinogen lysed at similar rates. However, when factor XIII was added, slower lysis was seen in gammaA/gamma' fibrin clots when compared with gammaA/gammaA fibrin clots. A D-dimer agglutination assay showed that the gammaA/gamma' clots were more highly cross-linked than the gammaA/gammaA clots. The lysis rates of gammaA/gamma' clots were similar to gammaA/gammaA clots in the presence of N-ethylmaleimide, a specific inhibitor of factor XIIIa. The gammaA/gamma' fibrin clots made in the presence of factor XIII showed increased proteolytic resistance to both plasmin and trypsin. Clots made from afibrinogenemic plasma reconstituted with gammaA/gamma' fibrinogen also showed significant resistance to lysis compared with gammaA/gammaA fibrinogen. These data demonstrate gammaA/gamma' fibrin is resistant to fibrinolysis, possibly as a result of concentrating factor XIII on the clot. The total fibrinogen concentration and the amount of gammaA/gamma' fibrinogen increase clot stability in vitro and thus may contribute independently to the risk of thrombosis in humans.

Thrombogenic and fibrinolytic factors and cardiovascular risk in non-insulin-dependent diabetes mellitus

Disturbances of the haemostatic system may favour the development of vascular damage and the final occlusion events in the progress of coronary heart disease (CHD). It has been shown recently in epidemiological studies, that increased concentration of several factors, mainly fibrinogen, factor VII, von Willebrand factor (vWF), and the fibrinolytic variables plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA), can be considered as risk factors for CHD. As morbidity and mortality through coronary atherosclerosis are higher in type 2 diabetic patients than in nondiabetic subjects and as insulin resistance represents a situation which favours the development of atherothrombosis, evaluation of the haemostatic factors which are recognized as risk factors may be interesting to consider in these situations. In fact, it has been shown that the fibrinolytic parameters PAI-1 and t-PA antigen are strongly related to the metabolic disorder of insulin resistance, whereas the link with fibrinogen, factor VII, and vWF remains weak. Many cross-sectional studies conducted in different populations have shown that PAI-1 and t-PA antigen (which represents t-PA/PAI-1 complexes) are strongly correlated with insulin, triglyceride, high-density lipoprotein (HDL) cholesterol, body mass index, walst-to-hip ratio and blood pressure, and that the improvement of insulin resistance improves in parallel the metabolic abnormalities and the concentration of the fibrinolytic parameters. Attempts at explaining the elevated PAI-1 and t-PA antigen levels in the insulin resistance syndrome have involved many clinical and in vitro studies, in which the role of insulin, insulin propeptides, very-low-density lipoprotein (VLDL) triglyceride, insulin resistance per se, glucose, and adipose tissue have successively been analysed and the main results of these studies are presented in this review. Due to recent experimental data from animal models of thrombosis, a pathogenic role of decreased fibrinolytic activity or increased PAI-1 levels can be proposed and could play a role in the development of vascular disease in subjects with Type 2 diabetes or insulin resistance.

High mortality from unidentified CVD in IDDM: time to start screening?

Mortality in insulin-dependent diabetes is markedly increased compared to the general population. Although strong associations have been found between renal disease and the risk of cardiovascular disease (CVD) the interaction between these two factors is not well understood. This study, which addresses risk factors for mortality in IDDM with a particular focus on the renal-CVD link, is based on the prospective Epidemiology of Diabetes Complications study. Thirty-seven (mean age 36 years, mean duration of IDDM 28 years at baseline) of the 658 IDDM individuals (mean age 28 years, mean duration of IDDM 20 years at baseline) have died in the first 4 years of follow up. A nested case-control study was performed, matching on sex and duration of diabetes. Twenty-two (59%) of the deaths were attributed to coronary heart disease, with an additional 16% attributed to diabetic coma. Only nine (41%) of the 22 individuals who died from cardiovascular disease had clinical evidence of coronary heart disease when seen for their last biennial exam. However, 54% of those who died of CVD without prior evidence did have evidence of lower extremity arterial disease. A strong link with renal disease was confirmed, with 81% of those with a coronary artery disease death having renal disease. Multivariate analyses suggest that smoking history, triglycerides and total platelet count are independent predictors of mortality, while LDL cholesterol best predicted CVD mortality. These results suggest a need for more intensive screening for cardiovascular disease, and correction of cardiovascular risk factors, in order to reduce the increased rate of mortality in this population. Efforts to prevent or delay the onset of renal disease may also be of benefit.