Plasma fibrinogen level and the risk of major cardiovascular diseases and nonvascular mortality: an individual participant meta-analysis

Fibrinogen and associated risk factors in a high-risk population: urban Indigenous Australians, the DRUID Study

Background

Epidemiological evidence suggests that fibrinogen and CRP are associated with coronary heart disease risk. High CRP in Indigenous Australians has been reported in previous studies including our 'Diabetes and Related diseases in Urban Indigenous population in Darwin region' (DRUID) Study. We studied levels of fibrinogen and its cross-sectional relationship with traditional and non-traditional cardiovascular risk factors in an urban Indigenous Australian cohort.

Methods

Fibrinogen data were available from 287 males and 628 females (aged ≥ 15 years) from the DRUID study. Analysis was performed for associations with the following risk factors: diabetes, HbA1c, age, BMI, waist circumference, waist-hip ratio, total cholesterol, triglyceride, HDL cholesterol, C-reactive protein, homocysteine, blood pressure, heart rate, urine ACR, smoking status, alcohol abstinence.

Results

Fibrinogen generally increased with age in both genders; levels by age group were higher than those previously reported in other populations, including Native Americans. Fibrinogen was higher in those with than without diabetes (4.24 vs 3.56 g/L, p < 0.001). After adjusting for age and sex, the following were significantly associated with fibrinogen: BMI, waist, waist-hip ratio, systolic blood pressure, heart rate, fasting triglycerides, HDL cholesterol, HbA1c, CRP, ACR and alcohol abstinence. On multivariate regression (age and sex-adjusted) CRP and HbA1c were significant independent predictors of fibrinogen, explaining 27% of its variance; CRP alone explained 25% of fibrinogen variance. On factor analysis, both CRP and fibrinogen clustered with obesity in women (this factor explained 20% of variance); but in men, CRP clustered with obesity (factor explained 18% of variance) whilst fibrinogen clustered with HbA1c and urine ACR (factor explained 13% of variance).

Conclusions

Fibrinogen is associated with traditional and non-traditional cardiovascular risk factors in this urban Indigenous cohort and may be a useful biomarker of CVD in this high-risk population. The apparent different associations of fibrinogen with cardiovascular disease risk markers in men and women should be explored further.

Association of genomic loci from a cardiovascular gene SNP array with fibrinogen levels in European Americans and African-Americans from six cohort studies: the Candidate Gene Association Resource (CARe)

Several common genomic loci, involving various immunity- and metabolism-related genes, have been associated with plasma fibrinogen in European Americans (EAs). The genetic determinants of fibrinogen in African Americans (AAs) are poorly characterized. Using a vascular gene-centric array in 23,634 EA and 6657 AA participants from 6 studies comprising the Candidate Gene Association Resource project, we examined the association of 47,539 common and lower frequency variants with fibrinogen concentration. We identified a rare Pro265Leu variant in FGB (rs6054) associated with lower fibrinogen. Common fibrinogen gene single nucleotide polymorphisms (FGB rs1800787 and FGG rs2066861) significantly associated with fibrinogen in EAs were prevalent in AAs and showed consistent associations. Several fibrinogen locus single nucleotide polymorphism associated with lower fibrinogen were exclusive to AAs; these include a newly reported association with FGA rs10050257. For IL6R, IL1RN, and NLRP3 inflammatory gene loci, associations with fibrinogen were concordant between EAs and AAs, but not at other loci (CPS1, PCCB, and SCL22A5-IRF1). The association of FGG rs2066861 with fibrinogen differed according to assay type used to measure fibrinogen. Further characterization of common and lower-frequency genetic variants that contribute to interpopulation differences in fibrinogen phenotype may help refine our understanding of the contribution of hemostasis and inflammation to atherothrombotic risk.

Statistical methods for the time-to-event analysis of individual participant data from multiple epidemiological studies

BACKGROUND

Meta-analysis of individual participant time-to-event data from multiple prospective epidemiological studies enables detailed investigation of exposure-risk relationships, but involves a number of analytical challenges.

METHODS

This article describes statistical approaches adopted in the Emerging Risk Factors Collaboration, in which primary data from more than 1 million participants in more than 100 prospective studies have been collated to enable detailed analyses of various risk markers in relation to incident cardiovascular disease outcomes.

RESULTS

Analyses have been principally based on Cox proportional hazards regression models stratified by sex, undertaken in each study separately. Estimates of exposure-risk relationships, initially unadjusted and then adjusted for several confounders, have been combined over studies using meta-analysis. Methods for assessing the shape of exposure-risk associations and the proportional hazards assumption have been developed. Estimates of interactions have also been combined using meta-analysis, keeping separate within- and between-study information. Regression dilution bias caused by measurement error and within-person variation in exposures and confounders has been addressed through the analysis of repeat measurements to estimate corrected regression coefficients. These methods are exemplified by analysis of plasma fibrinogen and risk of coronary heart disease, and Stata code is made available.

CONCLUSION

Increasing numbers of meta-analyses of individual participant data from observational data are being conducted to enhance the statistical power and detail of epidemiological studies. The statistical methods developed here can be used to address the needs of such analyses.

Fibrinogen and left ventricular myocardial systolic function: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Increasing evidence suggests that elevated plasma fibrinogen is associated with incident heart failure. However, the underlying pathophysiological mechanisms have not been well elucidated.

METHODS

We examined the relationship between plasma fibrinogen level and peak systolic midwall circumferential strain (Ecc) at the base, mid cavity, and apex of the left ventricle measured by magnetic resonance imaging myocardial tagging in 1096 participants without clinical cardiovascular disease enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA).

RESULTS

After adjustment for demographics, established risk factors and body mass index, elevated fibrinogen was independently associated with reductions in absolute Ecc indicative of impaired systolic function in all regions (all P < or = .015). The relationships were consistently significant upon further adjustment for measures of atherosclerosis (all P < .024) and were modestly attenuated with regional heterogeneity after additional adjustment for other inflammatory biomarker and N-terminal pro-brain natriuretic peptide. In this fully-adjusted model, every 1-SD (74 mg/dL) increment in plasma fibrinogen was independently associated with a reduction in left ventricular absolute Ecc of 0.29% (95% CI 0.03%-0.59%, P = .048) at the base, 0.22% (95% CI 0.006%-0.43%, P = .044) at mid cavity, 0.20% (95% CI = -0.035% to 0.43%, P = .097) at the apex, and 0.24% (95% CI = 0.05%-0.43%, P = .015) overall.

CONCLUSIONS

Among asymptomatic individuals without clinical cardiovascular disease, elevated fibrinogen is independently associated with impaired myocardial systolic function. These findings support roles of inflammation, procoagulation, and hyperviscosity underlying hyperfibrinogenemia in the pathogenesis of incipient myocardial dysfunction.

Antihyperlipidemic agents cause a decrease in von Willebrand factor levels in pediatric patients with familial hyperlipidemia

Familial hyperlipidemia is a group of genetic disorders with a predisposition to atherosclerosis. Hyperlipidemia causes increased atherosclerotic events through increased endothelial damage. In this report we aimed to measure the plasma fibrinogen and von Willebrand factor antigen (VWf:Ag) levels in pediatric patients with familial hyperlipidemias and to investigate the effects of serum lipid levels and antihyperlipidemic agents on these parameters. Of the 41 patients analyzed, vWf:Ag level was significantly lower in antihyperlipidemic receivers (132 +/- 51%, 102 +/- 19%; p = 0.010). This finding may indicate that early initiation of antihyperlipidemics in patients with familial hyperlipidemias may decrease the risk of future atherosclerotic events through not only decreasing the serum lipid levels, but also decreasing plasma vWf:Ag levels.

DAMPening inflammation by modulating TLR signalling

Damage-associated molecular patterns (DAMPs) include endogenous intracellular molecules released by activated or necrotic cells and extracellular matrix (ECM) molecules that are upregulated upon injury or degraded following tissue damage. DAMPs are vital danger signals that alert our immune system to tissue damage upon both infectious and sterile insult. DAMP activation of Toll-like receptors (TLRs) induces inflammatory gene expression to mediate tissue repair. However, DAMPs have also been implicated in diseases where excessive inflammation plays a key role in pathogenesis, including rheumatoid arthritis (RA), cancer, and atherosclerosis. TLR activation by DAMPs may initiate positive feedback loops where increasing tissue damage perpetuates pro-inflammatory responses leading to chronic inflammation. Here we explore the current knowledge about distinct signalling cascades resulting from self TLR activation. We also discuss the involvement of endogenous TLR activators in disease and highlight how specifically targeting DAMPs may yield therapies that do not globally suppress the immune system.

Elevated plasma fibrinogen caused by inadequate alpha-linolenic acid intake can be reduced by replacing fat with canola-type rapeseed oil

The effects of canola-type rapeseed oil (RSO) on serum lipids, plasma fibrinogen, lipid oxidation and fatty acids were studied in three groups of subjects, two of which had not been consuming fish in their habitual diets. Forty-two volunteers (35 women, 7 men, 16-62 years) replaced fat with RSO for 6 weeks in a parallel design. The average cholesterol and fibrinogen concentrations were 5.0 mmol/l and 2.6 g/l, respectively. The intake of alpha-linolenic acid (alpha-LLA) was doubled. Efficient competitive inhibition by alpha-LLA was seen as a decrease in long-chain (LC) n-6 PUFA at 3 weeks. Elevated fibrinogen (2.6-3.9 g/l) decreased by 0.95 g/l at 6 weeks. Docosahexaenoic acid (22:6n-3) in plasma phospholipids increased at low fibrinogen levels only. The associations and changes in plasma C18 and LC PUFA followed the competitive and metabolic principles of the body, and especially in the case of n-3 PUFA according to the recycling pathway.

Is a low blood level of vitamin B12 a cardiovascular and diabetes risk factor? A systematic review of cohort studies

PURPOSE

To assess the prior hypothesis that low blood vitamin B12, partly through hyperhomocysteinemia and partly through direct effects, increases the risk of cardiovascular diseases and diabetes. As background, we also extracted all-cause mortality from the studies that met our criteria.

METHODS

A systematic review of prospective cohort studies identified through searching six electronic databases, screening of reference lists, and citation search. Included studies reported data on the association between vitamin B12 blood levels, or other appropriate surrogate biological markers e.g. holotranscobalamin or serum/urine methylmalonic acid, and fatal or non-fatal incident diabetes and cardiovascular events.

RESULTS

Seven studies were included. Studies differed regarding the population studied, length of follow-up, study outcomes, and data analysis--a narrative synthesis approach was performed to examine the results. Most studies met few of the quality assessment criteria which were adapted from the Scottish Intercollegiate Guidelines Network (SIGN). Only one high-quality study reported that low B12 increased the risk of incident cerebral ischaemia (RR = 1.76; 95% CI = 1.16-2.68). After controlling for homocysteine, the association persisted although weakened (RR = 1.57; 95% CI = 1.02-2.43), suggesting that the effects of low B12 were only partly mediated by homocysteine. In two studies, higher B12 levels were associated with a greater risk of total mortality (RR = 1.00; 95% CI = 1.00-1.00 and HR = 1.15; 95% CI = 1.08-1.22, respectively) and combined fatal and non-fatal coronary events (RR = 1.00; 95% CI = 1.00-1.00). No association between study outcomes and vitamin B12 levels was found in four other studies.

CONCLUSIONS

Surprisingly, there is only very limited evidence that vitamin B12 deficiency predisposes to the risk of mortality and morbidity from either cardiovascular diseases or diabetes in adults. Current data do not support vitamin B12 supplementation to reduce the risk of cardiovascular diseases or diabetes.

Carotid plaque, stroke pathogenesis, and CRP: treatment of ischemic stroke

Inflammation is receiving increased attention as a cause of atherosclerosis and stroke. Several inflammatory biomarkers, and particularly high-sensitivity C-reactive protein (hsCRP), have been identified as likely predictors of the risk of a future stroke. In clinical settings, it has been consistently observed that higher concentrations of CRP are associated with larger brain infarcts, stroke severity, neurologic disability, and future vascular events. However, there is still controversy over the degree of risk conferred by elevated CRP concentrations. Some studies reported that the predictive value of CRP is moderate compared with classical risk factors and is only weakly related to cardiovascular damage after adjustment for traditional cardiovascular risk factors. CRP like many other hemostatic factors is an acute-phase protein and, therefore, it is not always clear whether its association with cerebrovascular disease reflects its contribution to atherothrombosis, its acute-phase condition, or both. Furthermore, the value of single measurements of CRP in patients with concurrent infection or other inflammatory conditions has not been established and reported data should be interpreted cautiously. Several drugs, especially hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), have been demonstrated to reduce hsCRP levels independently of their effects on plasma cholesterol. Recently, emerging therapies have been aimed at the control of blood pressure and inflammation in stroke patients. Whether a reduction of hsCRP levels could be beneficial to stroke patients remains to be clarified, and it is also unclear whether other drugs may be useful to lower hsCRP levels. More studies are needed before hsCRP becomes a routine part of the evaluation of stroke patients. This should also prompt the search for new agents directly blocking CRP actions.

Objectively measured secondhand smoke exposure and risk of cardiovascular disease: what is the mediating role of inflammatory and hemostatic factors?

OBJECTIVES

The aim of this study was to examine the association between objectively measured secondhand smoke (SHS) exposure and incident cardiovascular disease (CVD) death and assess the extent to which this association can be explained through novel circulating markers of inflammation and hemostasis.

BACKGROUND

Existing evidence suggests there is an association between SHS and CVD risk, although the mechanisms remain poorly understood.

METHODS

In a prospective study of 13,443 participants living in England and Scotland (age 53.5 +/- 12.6 years, 52.3% women), we measured salivary cotinine (an objective marker of SHS exposure) and novel CVD biomarkers (C-reactive protein, fibrinogen) at baseline.

RESULTS

Of the sample, 20.8% had high SHS exposure on the basis of elevated levels of salivary cotinine (range 0.71 to 14.99 ng/ml). During a mean follow-up of 8 years, there were 1,221 all-cause deaths and 364 CVD deaths. High SHS was associated with all-cause (age-adjusted hazard ratio [HR]: 1.25, 95% confidence interval [CI]: 1.02 to 1.53) and CVD death (age-adjusted HR: 1.21, 95% CI: 0.85 to 1.73). High SHS was also associated with elevated CRP, which explained 48% of the association between SHS and CVD death. The excess risk of CVD associated with active smoking was exaggerated in relation to self report (age-adjusted HR: 3.27, 95% CI: 2.48 to 4.31) compared with objective assessment (age-adjusted HR: 2.44, 95% CI: 1.75 to 3.40).

CONCLUSIONS

Among a large representative sample of British adults we observed elevated levels of low-grade inflammation in otherwise healthy participants exposed to high SHS, and this partly explained their elevated risk of CVD death.

Predicting the risk of coronary heart disease. II: the role of novel molecular biomarkers and genetics in estimating risk, and the future of risk prediction

This is the second of two articles reviewing recent findings about the risk of coronary heart disease. This paper is concerned with novel molecular biomarkers, genetic markers of risk and the future of risk prediction.

Systemic inflammation, heart rate variability and air pollution in a cohort of senior adults

OBJECTIVES

Short-term elevation of ambient particulate air pollution has been associated with autonomic dysfunction and increased systemic inflammation, but the interconnections between these pathways are not well understood. We examined the association between inflammation and autonomic dysfunction and effect modification of inflammation on the association between air pollution and heart rate variability (HRV) in elderly subjects.

METHODS

25 elderly subjects in Steubenville, Ohio, were followed up to 24 times with repeated 30-min ECG Holter monitoring (545 observations). C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), soluble inter-cellular adhesion molecule 1 (sICAM-1), and white blood cell and platelet counts were measured in peripheral blood samples collected in the first month of the study. Increased systemic inflammation was defined for subjects within the upper 20% of the distribution for each marker. A central ambient monitoring station provided daily fine particle (PM(2.5)) and sulphate (SO(4)(2-)) data. Linear mixed models were used to identify associations between inflammatory markers and HRV and to assess effect modification of the association between air pollution and HRV due to inflammatory status.

RESULTS

A 5.8 mg/l elevation in CRP was associated with decreases of between -8% and -33% for time and frequency domain HRV outcomes. A 5.1 microg/m(3) increase in SO(4)(2-) on the day before the health assessment was associated with a decrease of -6.7% in the SD of normal RR intervals (SDNN) (95% CI -11.8% to -1.3%) in subjects with elevated CRP, but not in subjects with lower CRP (p value interaction=0.04), with similar findings for PM(2.5).

CONCLUSIONS

Increased systemic inflammation is associated with autonomic dysfunction in the elderly. Air pollution effects on reduced SDNN are stronger in subjects with elevated systemic inflammation.

Circulating levels of coagulation and inflammation markers and cancer risks: individual participant analysis of data from three long-term cohorts

BACKGROUND

Basic and clinical research support the hypothesis that activation of the coagulation and inflammation pathways may affect cancer onset, but there is limited epidemiological data to support this.

METHODS

We examined a large range of haemostatic and inflammation markers, including fibrinogen, in 19 303 male participants from three English cohorts followed for up to 30 years. After excluding the first 3 years of follow-up, 2908 incident cancers were accrued. Competing risk models were fitted to estimate rate ratios (RRs) for cancer incidence, adjusting for age and other confounders.

RESULTS

Baseline white blood cell (WBC) count and circulating levels of fibrinogen, C-reactive protein (CRP), factor VII antigen (VIIa) and prothrombin fragment F1.2 were positively associated with risk of smoking-related cancers, particularly lung cancer. The magnitude of these associations was highest for persistently raised fibrinogen levels. There was, however, substantial confounding by smoking with risk being fully (WBC, CRP and VIIa) or partially (fibrinogen) removed after adjustment. The pooled RRs (95% confidence interval) per one standard deviation increase in fibrinogen levels before and after adjustment for smoking habits were 1.23 (1.12, 1.36) and 1.12 (1.05, 1.20), respectively. The fibrinogen associations were present only among current smokers at entry. The effect of smoking on smoking-related cancers was partly mediated by fibrinogen levels.

CONCLUSIONS

Our results are consistent with elevated circulating levels of fibrinogen and F1.2 being predictors of risk of smoking-related cancers. Further research is necessary to clarify whether elevated levels of fibrinogen and F1.2 are causally relevant or simply correlates of the smoking-cancer association.

Leukocyte counts, myeloperoxidase, and pregnancy-associated plasma protein a as biomarkers for cardiovascular disease: towards a multi-biomarker approach

We evaluated leukocyte counts and levels of CRP, fibrinogen, MPO, and PAPP-A in patients with stable and unstable angina pectoris, acute myocardial infarction, and healthy controls. All biomarkers were analyzed again after 6 months. Leukocyte counts and concentrations of fibrinogen, CRP, MPO, and PAPP-A were significantly increased in patients with acute myocardial infarction. Leukocyte counts and concentrations of MPO were significantly increased in patients with unstable angina pectoris compared with controls. After 6 months, leukocyte counts and MPO concentrations were still increased in patients with acute myocardial infarction when compared to controls. Discriminant analysis showed that leukocyte counts, MPO, and PAPP-A concentrations classified study group designation for acute coronary events correctly in 83% of the cases. In conclusion, combined assessment of leukocyte counts, MPO, and PAPP-A was able to correctly classify acute coronary events, suggesting that this could be a promising panel for a multibiomarker approach to assess cardiovascular risk.

Emerging applications of nanomedicine for the diagnosis and treatment of cardiovascular diseases

Nanomedicine is an emerging field that utilizes nanotechnology concepts for advanced therapy and diagnostics. This convergent discipline merges research areas such as chemistry, biology, physics, mathematics and engineering. It therefore bridges the gap between molecular and cellular interactions, and has the potential to revolutionize medicine. This review presents recent developments in nanomedicine research poised to have an important impact on the treatment of cardiovascular disease. This will occur through improvement of the diagnosis and therapy of cardiovascular disorders as atherosclerosis, restenosis and myocardial infarction. Specifically, we discuss the use of nanoparticles for molecular imaging and advanced therapeutics, specially designed drug eluting stents and in vivo/ex vivo early detection techniques.

The Lp-PLA2 Studies Collaboration. Lipoprotein-associated phospholipase A(2) and risk of coronary disease, stroke, and mortality: collaborative analysis of 32 prospective studies

BACKGROUND

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), an inflammatory enzyme expressed in atherosclerotic plaques, is a therapeutic target being assessed in trials of vascular disease prevention. We investigated associations of circulating Lp-PLA(2) mass and activity with risk of coronary heart disease, stroke, and mortality under different circumstances.

METHODS

With use of individual records from 79 036 participants in 32 prospective studies (yielding 17 722 incident fatal or non-fatal outcomes during 474 976 person-years at risk), we did a meta-analysis of within-study regressions to calculate risk ratios (RRs) per 1 SD higher value of Lp-PLA(2) or other risk factor. The primary outcome was coronary heart disease.

FINDINGS

Lp-PLA(2) activity and mass were associated with each other (r=0.51, 95% CI 0.47-0.56) and proatherogenic lipids. We noted roughly log-linear associations of Lp-PLA(2) activity and mass with risk of coronary heart disease and vascular death. RRs, adjusted for conventional risk factors, were: 1.10 (95% CI 1.05-1.16) with Lp-PLA(2) activity and 1.11 (1.07-1.16) with Lp-PLA(2) mass for coronary heart disease; 1.08 (0.97-1.20) and 1.14 (1.02-1.27) for ischaemic stroke; 1.16 (1.09-1.24) and 1.13 (1.05-1.22) for vascular mortality; and 1.10 (1.04-1.17) and 1.10 (1.03-1.18) for non-vascular mortality, respectively. RRs with Lp-PLA(2) did not differ significantly in people with and without initial stable vascular disease, apart from for vascular death with Lp-PLA(2) mass. Adjusted RRs for coronary heart disease were 1.10 (1.02-1.18) with non-HDL cholesterol and 1.10 (1.00-1.21) with systolic blood pressure.

INTERPRETATION

Lp-PLA(2) activity and mass each show continuous associations with risk of coronary heart disease, similar in magnitude to that with non-HDL cholesterol or systolic blood pressure in this population. Associations of Lp-PLA(2) mass and activity are not exclusive to vascular outcomes, and the vascular associations depend at least partly on lipids.

FUNDING

UK Medical Research Council, GlaxoSmithKline, and British Heart Foundation.

Gamma' fibrinogen: evaluation of a new assay for study of associations with cardiovascular disease

BACKGROUND

Studies of disease associations with gamma' fibrinogen, a newly emerging risk factor for cardiovascular disease, have been hampered by the lack of a standardized and well-characterized assay.

METHODS

We developed an immunometric technique to measure gamma' fibrinogen concentrations in plasma and studied the clinical utility of this test in samples from healthy individuals enrolled in the Framingham Offspring Study and in a separate case/control study of coronary artery disease (CAD). Monoclonal antibody 2.G2.H9, specific for the unique carboxyl terminal peptide of the fibrinogen gamma' chain, was used as capture antibody. Sheep antihuman fibrinogen/horseradish peroxidase conjugate was used for detection, with 3,3',5,5'-tetramethylbenzidine as substrate. We evaluated the linearity, imprecision, analytical specificity, and lower limit of quantification of the assay. We determined the reference interval for gamma' fibrinogen in healthy individuals from the Framingham Offspring Study (n = 2879) and quantified associations between gamma' fibrinogen and cardiovascular disease risk factors. The sensitivity and specificity of gamma' fibrinogen in evaluating CAD patients (n = 133) was determined with ROC curve analysis.

RESULTS

The gamma' fibrinogen ELISA had within-run CVs of 13.4% at 0.127 g/L and 4.8% at 0.416 g/L. The limit of quantification at an imprecision of 20% was 0.10 g/L. The reference interval for healthy individuals was 0.088-0.551 g/L. ROC curve analysis of results from patients with CAD yielded an area under the curve of 0.76, with a diagnostic accuracy of 0.78 at a decision threshold of 0.30 g/L.

CONCLUSIONS

gamma' Fibrinogen shows excellent utility for cardiovascular risk analysis.

C-reactive protein and venous thromboembolism. A prospective investigation in the ARIC cohort

The role of inflammation in the causation of venous thromboembolism (VTE) is uncertain. In 10,505 participants of the Atherosclerosis Risk in Communities (ARIC) Study, we assessed the association of the systemic inflammation marker, elevated C-reactive protein (CRP), with incidence of VTE (n=221) over a median of 8.3 years of follow-up. Adjusted for age, race, and sex, the hazard ratios of VTE across quintiles of CRP were 1.0, 1.61, 1.16, 1.56, and 2.31 (p for trend p<0.0007). For CRP above the upper 10 percentile (> or = 8.55 mg/L), compared with the lowest 90% of CRP values, the hazard ratio of VTE was 2.07 (95% CI 1.47, 2.94). Further adjustment for baseline hormone replacement therapy, diabetes, and body mass index attenuated the hazard ratios only slightly. For example, the adjusted hazard ratio of VTE was 1.76 (95% CI 1.23, 2.52) for CRP above versus below the 90(th) percentile. In conclusion, this prospective, population-based study suggests elevated CRP is independently associated with increased risk of VTE.

[Depression and cardiovascular disease--is there an association?]

BACKGROUND

Depression is associated with an increased risk of cardiovascular events. This review presents data from recent cohort- and interventional studies, and possible pathogenetic mechanisms.

MATERIAL AND METHODS

The article is based on literature from the period 1998 - 2008 identified through a non-systematic search in Medline.

RESULTS

Epidemiological studies of patients (outside of hospitals) with clinical depression suggest they have an increased risk of cardiovascular events. Possible mechanisms responsible for this increased cardiovascular risk are: an increased prevalence of unhealthy lifestyle factors, systemic inflammation, endocrine or autonomic dysfunction, increased platelet reactivity or endothelial dysfunction. Treatment with antidepressive drugs has not reduced the risk of cardiovascular events.

INTERPRETATION

Clinicians should be aware of the influence of depression on cardiovascular risk.

Income, education, and inflammation: differential associations in a national probability sample (The MIDUS study)

OBJECTIVE

To examine the associations between income and education and three markers of inflammation: interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen. Socioeconomic status is inversely linked with health outcomes, but the biological processes by which social position "gets under the skin" to affect health are poorly understood.

METHOD

Cross-sectional analyses involved participants (n = 704) from the second wave of the national population-based Survey of Midlife Development in the United States (MIDUS). Data on pretax household-adjusted income and educational attainment were collected by questionnaire and telephone interview, respectively. Detailed medical history interviews, inventories of medication, and fasting blood samples for assessment of inflammatory proteins were obtained during an overnight clinic stay.

RESULTS

All three inflammatory proteins were inversely associated with both income and education in bivariate analyses. However, multivariate regression models, adjusting for potential confounds, showed that only low income predicted higher levels of inflammatory proteins. Moreover, inclusion of IL-6 in the regression models for CRP and fibrinogen eliminated the associations with income.

CONCLUSION

These results suggest that income explains the association between education and peripheral inflammation. In short, the reason that higher education is linked to reduced peripheral inflammation is because it reduces the risk for low income status, which is what is directly associated with reduced peripheral inflammation. The findings also suggest that the links between income and both CRP and fibrinogen are mediated by IL-6. These observations help to sharpen our understanding of the relationship between social position and biological markers of illness in the United States.

Association of novel genetic Loci with circulating fibrinogen levels: a genome-wide association study in 6 population-based cohorts

BACKGROUND

Fibrinogen is both central to blood coagulation and an acute-phase reactant. We aimed to identify common variants influencing circulation fibrinogen levels.

METHODS AND RESULTS

We conducted a genome-wide association analysis on 6 population-based studies, the Rotterdam Study, the Framingham Heart Study, the Cardiovascular Health Study, the Atherosclerosis Risk in Communities Study, the Monitoring of Trends and Determinants in Cardiovascular Disease/KORA Augsburg Study, and the British 1958 Birth Cohort Study, including 22 096 participants of European ancestry. Four loci were marked by 1 or more single-nucleotide polymorphisms that demonstrated genome-wide significance (P<5.0 x 10(-8)). These included a single-nucleotide polymorphism located in the fibrinogen beta chain (FGB) gene and 3 single-nucleotide polymorphisms representing newly identified loci. The high-signal single-nucleotide polymorphisms were rs1800789 in exon 7 of FGB (P=1.8 x 10(-30)), rs2522056 downstream from the interferon regulatory factor 1 (IRF1) gene (P=1.3 x 10(-15)), rs511154 within intron 1 of the propionyl coenzyme A carboxylase (PCCB) gene (P=5.9 x 10(-10)), and rs1539019 on the NLR family pyrin domain containing 3 isoforms (NLRP3) gene (P=1.04 x 10(-8)).

CONCLUSIONS

Our findings highlight biological pathways that may be important in regulation of inflammation underlying cardiovascular disease.

Longitudinal assessment of fibrinogen in relation to subclinical cardiovascular disease: the CARDIA study

OBJECTIVE

To examine the strength of the associations of fibrinogen with subclinical atherosclerosis in healthy persons.

METHODS

A population-based, prospective, observational study of black and white men and women (Coronary Artery Risk Development in Young Adults [CARDIA]). Fibrinogen levels were measured at year 7 (ages 25-37, n = 2969), and again at year 20 (ages 38-50, n = 2832). Measures of subclinical atherosclerosis (coronary artery calcification [CAC] and carotid intimal-medial thickness [CIMT]) were recorded at year 20.

RESULTS

Over the 13-year study interval (1992-1993 to 2005-2006), fibrinogen rose from a mean of 3.32 to 4.05 g L(-1). After adjusting for age, gender and race, fibrinogen was positively associated with greater incidence of CAC and increased CIMT cross-sectionally as well as after 13 years of follow-up (all P-trend < 0.001). After further adjustment for field center, BMI, smoking, education, systolic blood pressure, diabetes, antihypertensive medication use, total and HDL cholesterol, and CRP, significant positive relationships between fibrinogen and incidence of CAC remained for the total cohort longitudinally (P-trend = 0.037), but not cross-sectionally (P-trend = 0.147).

CONCLUSION

This 13-year study demonstrates that higher levels of fibrinogen during young adulthood are positively associated with incidence of CAC and increased CIMT in middle-age, but the strength of the association declines with increasing age.

Whole and refined grain intakes are related to inflammatory protein concentrations in human plasma

Inflammation may play a role in the pathogenesis of cardiovascular disease and type 2 diabetes, and it has been suggested that the protective effects of whole-grain consumption could be mediated by an effect on inflammation, although few studies have examined the relationships between grain intakes and inflammatory protein concentrations. Our objectives in this study were to examine the associations of whole grain and refined grain intake with plasminogen activator inhibitor type 1 (PAI-1), C-reactive protein (CRP), and fibrinogen plasma concentrations. Cross-sectional data from the Insulin Resistance Atherosclerosis Study were used to perform multiple regression analyses using dietary information on whole and refined grain intakes from a FFQ and clinical measures of plasma inflammatory protein concentrations in participants free of type 2 diabetes. After adjustment for demographic, lifestyle, and dietary variables, whole-grain intake was inversely related to log PAI-1 (beta = -0.102; SEM = 0.038; P = 0.0077) and log CRP (beta = -0.102; SEM = 0.048; P = 0.0340). Adding insulin sensitivity, waist circumference, and 2-h postload glucose to the model attenuated both associations to nonsignificance. Refined grain was positively related to log PAI-1 in the multivariate model (beta = 0.076; SEM = 0.034; P = 0.0251) and the relationship remained unchanged by additional adjustment for metabolic variables. Fibrinogen concentrations were not related to whole or refined grain intake. In summary, whole grain intake was inversely related to PAI-1 and CRP plasma concentrations, but these relationships were attenuated by the addition of metabolic variables to the model. Refined grain intake was positively independently related to plasma PAI-1 concentrations.

Carbohydrate recognition by boronolectins, small molecules, and lectins

Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents. However, this potential is far from being realized. One key issue is the difficulty in the development of "binders" capable of specific recognition of carbohydrates of biological relevance. This review discusses systematically the general approaches that are available in developing carbohydrate sensors and "binders/receptors," and their applications. The focus is on discoveries during the last 5 years.

Haemorheological predictors of cognitive decline: the Edinburgh Artery Study

INTRODUCTION

vascular risk factors and diseases can negatively impact cognitive function. Determinants of blood flow are implicated in thrombogenesis and ischaemic events, yet little is known about their relationship with cognition.

METHODS

blood rheology data were collected in 1987/88, and cognitive testing was performed in 1998/99 when the mean (+ or - standard deviation) age of the study sample was 73.1 years (+ or - 5.0). Follow-up assessment was performed 4 years later. Information was collected on verbal declarative memory, non-verbal reasoning, verbal fluency, information processing speed and a general cognitive factor representing the variance common to the individual test scores.

RESULTS

after controlling for age, sex and cognitive performance in 1998/99, blood viscosity (BV) (P < 0.05) and fibrinogen (P < 0.05) predicted decline in non-verbal reasoning over 4 years. When estimated from pre-morbid level, decline in general cognition (P < 0.05), non-verbal reasoning (P < 0.05) and information processing speed (P < 0.01) was associated with BV levels. Haematocrit (HCT) had similar effects (P < 0.01 to P < 0.001). All associations persisted after control for multiple confounders. When examined together, HCT but not BV independently predicted cognitive decline.

CONCLUSIONS

blood rheology is independently related to cognitive decline in older people. The value of strategies aimed at preserving cognition through influencing blood rheology needs investigation.

Fibrinogen beta variants confer protection against coronary artery disease in a Greek case-control study

Background

Although plasma fibrinogen levels are related to cardiovascular risk, data regarding the role of fibrinogen genetic variation in myocardial infarction (MI) or coronary artery disease (CAD) etiology remain inconsistent. The purpose of the present study was to investigate the effect of fibrinogen A (FGA), fibrinogen B (FGB) and fibrinogen G (FGG) gene SNPs and haplotypes on susceptibility to CAD in a homogeneous Greek population.

Methods

We genotyped for rs2070022, rs2070016, rs2070006 in FGA gene, the rs7673587, rs1800789, rs1800790, rs1800788, rs1800787, rs4681 and rs4220 in FGB gene and for the rs1118823, rs1800792 and rs2066865 SNPs in FGG gene applying an arrayed primer extension-based genotyping method (APEX-2) in a sample of CAD patients (n = 305) and controls (n = 305). Logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), before and after adjustment for potential confounders.

Results

None of the FGA and FGG SNPs and FGA, FGB, FGG and FGA-FGG haplotypes was associated with disease occurrence after adjustment. Nevertheless, rs1800787 and rs1800789 SNPs in FGB gene seem to decrease the risk of CAD, even after adjustment for potential confounders (OR = 0.42, 95%CI: 0.19-0.90, p = 0.026 and OR = 0.44, 95%CI:0.21-0.94, p = 0.039, respectively).

Conclusions

FGA and FGG SNPs as well as FGA, FGB, FGG and FGA-FGG haplotypes do not seem to be important contributors to CAD occurrence in our sample. On the contrary, FGB rs1800787 and rs1800789 SNPs seem to confer protection to disease onset lowering the risk by about 50% in homozygotes for the minor alleles.

C-reactive protein concentration and risk of coronary heart disease, stroke, and mortality: an individual participant meta-analysis

BACKGROUND

Associations of C-reactive protein (CRP) concentration with risk of major diseases can best be assessed by long-term prospective follow-up of large numbers of people. We assessed the associations of CRP concentration with risk of vascular and non-vascular outcomes under different circumstances.

METHODS

We meta-analysed individual records of 160 309 people without a history of vascular disease (ie, 1.31 million person-years at risk, 27 769 fatal or non-fatal disease outcomes) from 54 long-term prospective studies. Within-study regression analyses were adjusted for within-person variation in risk factor levels.

RESULTS

Log(e) CRP concentration was linearly associated with several conventional risk factors and inflammatory markers, and nearly log-linearly with the risk of ischaemic vascular disease and non-vascular mortality. Risk ratios (RRs) for coronary heart disease per 1-SD higher log(e) CRP concentration (three-fold higher) were 1.63 (95% CI 1.51-1.76) when initially adjusted for age and sex only, and 1.37 (1.27-1.48) when adjusted further for conventional risk factors; 1.44 (1.32-1.57) and 1.27 (1.15-1.40) for ischaemic stroke; 1.71 (1.53-1.91) and 1.55 (1.37-1.76) for vascular mortality; and 1.55 (1.41-1.69) and 1.54 (1.40-1.68) for non-vascular mortality. RRs were largely unchanged after exclusion of smokers or initial follow-up. After further adjustment for fibrinogen, the corresponding RRs were 1.23 (1.07-1.42) for coronary heart disease; 1.32 (1.18-1.49) for ischaemic stroke; 1.34 (1.18-1.52) for vascular mortality; and 1.34 (1.20-1.50) for non-vascular mortality.

INTERPRETATION

CRP concentration has continuous associations with the risk of coronary heart disease, ischaemic stroke, vascular mortality, and death from several cancers and lung disease that are each of broadly similar size. The relevance of CRP to such a range of disorders is unclear. Associations with ischaemic vascular disease depend considerably on conventional risk factors and other markers of inflammation.

FUNDING

British Heart Foundation, UK Medical Research Council, BUPA Foundation, and GlaxoSmithKline.

Mechanisms of fibrinogen-induced microvascular dysfunction during cardiovascular disease

Fibrinogen (Fg) is a high molecular weight plasma adhesion protein and a biomarker of inflammation. Many cardiovascular and cerebrovascular disorders are accompanied by increased blood content of Fg. Increased levels of Fg result in changes in blood rheological properties such as increases in plasma viscosity, erythrocyte aggregation, platelet thrombogenesis, alterations in vascular reactivity and compromises in endothelial layer integrity. These alterations exacerbate the complications in peripheral blood circulation during cardiovascular diseases such as hypertension, diabetes and stroke. In addition to affecting blood viscosity by altering plasma viscosity and erythrocyte aggregation, growing experimental evidence suggests that Fg alters vascular reactivity and impairs endothelial cell layer integrity by binding to its endothelial cell membrane receptors and activating signalling mechanisms. The purpose of this review is to discuss experimental data, which demonstrate the effects of Fg causing vascular dysfunction and to offer possible mechanisms for these effects, which could exacerbate microcirculatory complications during cardiovascular diseases accompanied by increased Fg content.

Interaction between fibrinogen and IL-6 genetic variants and associations with cardiovascular disease risk in the Cardiovascular Health Study

The inflammatory cytokine interleukin-6 (IL-6) is a main regulator of fibrinogen synthesis, though its interaction with fibrinogen genes (FGA, FGB, FGG) and subsequent impact on cardiovascular disease (CVD) risk is not well-studied. We investigated joint associations of fibrinogen and IL6 tagSNPs with fibrinogen concentrations, carotid intima-media thickness, and myocardial infarction or ischemic stroke in 3900 European-American Cardiovascular Health Study participants. To identify combinations of genetic main effects and interactions associated with outcomes, we used logic regression. We also evaluated whether the relationship between fibrinogen SNPs and fibrinogen level varied by IL-6 level using linear regression models with multiplicative interaction terms. Combinations of fibrinogen and IL6 SNPs were significantly associated with fibrinogen level (p < 0.005), but not with other outcomes. Fibrinogen levels were higher in individuals having FGB1437 (rs1800790) and lacking FGA6534 (rs6050) minor alleles; these SNPs interacted with IL6 rs1800796 to influence fibrinogen level. Marginally significant (p= 0.03) interactions between IL-6 level and FGA and FGG promoter SNPs associated with fibrinogen levels were detected. We identified potential gene-gene interactions influencing fibrinogen levels. Although IL-6 responsive binding sites are present in fibrinogen gene promoter regions, we did not find strong evidence of interaction between fibrinogen SNPs and IL6 SNPs or levels influencing CVD.

Prediction of incident stroke events based on retinal vessel caliber: a systematic review and individual-participant meta-analysis

The caliber of the retinal vessels has been shown to be associated with stroke events. However, the consistency and magnitude of association, and the changes in predicted risk independent of traditional risk factors, are unclear. To determine the association between retinal vessel caliber and the risk of stroke events, the investigators combined individual data from 20,798 people, who were free of stroke at baseline, in 6 cohort studies identified from a search of the Medline (National Library of Medicine, Bethesda, Maryland) and EMBASE (Elsevier B.V., Amsterdam, the Netherlands) databases. During follow-up of 5-12 years, 945 (4.5%) incident stroke events were recorded. Wider retinal venular caliber predicted stroke (pooled hazard ratio = 1.15, 95% confidence interval: 1.05, 1.25 per 20-micron increase in caliber), but the caliber of retinal arterioles was not associated with stroke (pooled hazard ratio = 1.00, 95% confidence interval: 0.92, 1.08). There was weak evidence of heterogeneity in the hazard ratio for retinal venular caliber, which may be attributable to differences in follow-up strategies across studies. Inclusion of retinal venular caliber in prediction models containing traditional stroke risk factors reassigned 10.1% of people at intermediate risk into different, mostly lower, risk categories.

Fibrin clot properties in acute ischemic stroke: relation to neurological deficit

INTRODUCTION

Hypercoagulable state occurs in patients with acute vascular events. We wondered whether clot structure/function is altered in acute ischemic stroke (AIS), like in acute myocardial infarction.

PATIENTS AND METHODS

In 45 consecutive patients with AIS (24M, 21F), aged 67.4+/-10.9 years, and 45 healthy controls matched for age and sex, we investigated plasma fibrin clot structure/function by permeation, turbidity, and efficiency of fibrinolysis.

RESULTS

Compared to controls, AIS patients produced clots that had 30.5% less porous network (p<0.0001), were less susceptible to fibrinolysis (10.8% longer lysis time, p=0.001), were 20.5% more compact (p<0.0001), had 17.1% higher clot mass (p<0.0001), and showed increased (by 10.2%) overall fiber thickness (p<0.0001) with 8% shorter lag phase of fibrin formation (p=0.0002). Maximum rate of D-dimer release from clots was similar. Multiple regression analyses for all subjects (n=90) showed that being a stroke patient (p<0.0001), fibrinogen (p<0.0001) and lipoprotein(a) (p=0.0075) were independent predictors of clot permeability (model R2 0.79). Only fibrinogen (p<0.0001) and lipoprotein(a) (p=0.0026) predicted lysis time. All other fibrin parameters were predicted only by being a stroke patient. Clot compaction was associated with neurological deficit on admission (r=-0.81; p<0.0001) and at discharge (r=-0.69; p<0.0001). Patients with 0 or 1 point in the modified Rankin scale (n=19) had 13.3% higher clot permeability compared to the remainder (p=0.02).

CONCLUSIONS

This study is the first to show that AIS is associated with unfavorably altered fibrin clot properties that might correlate with neurological deficit.

Mendelian randomization in nutritional epidemiology

Nutritional epidemiology aims to identify dietary and lifestyle causes for human diseases. Causality inference in nutritional epidemiology is largely based on evidence from studies of observational design, and may be distorted by unmeasured or residual confounding and reverse causation. Mendelian randomization is a recently developed methodology that combines genetic and classical epidemiological analysis to infer causality for environmental exposures, based on the principle of Mendel's law of independent assortment. Mendelian randomization uses genetic variants as proxies for environmental exposures of interest. Associations derived from Mendelian randomization analysis are less likely to be affected by confounding and reverse causation. During the past 5 years, a body of studies examined the causal effects of diet/lifestyle factors and biomarkers on a variety of diseases. The Mendelian randomization approach also holds considerable promise in the study of intrauterine influences on offspring health outcomes. However, the application of Mendelian randomization in nutritional epidemiology has some limitations.

Feeding acutely stimulates fibrinogen synthesis in healthy young and elderly adults

Fibrinogen is a positive acute-phase protein and its hepatic synthesis is enhanced following inflammation and injury. However, it is not clear whether fibrinogen synthesis is also responsive to oral nutrients and whether the response to a meal may be affected by age. Our aim in this study was to investigate the acute effect of oral feeding on fibrinogen synthesis in both young and elderly men and women. Fibrinogen synthesis was determined in 3 separate occasions from the incorporation of l[(2)H(5)]phenylalanine (43 mg/kg body weight) in 8 young (21-35 y) and 8 elderly (>60 y) participants following the ingestion of water (control), a complete liquid meal (15% protein, 30% fat, and 55% carbohydrate), or only the protein component of the meal. The ingestion of the complete meal enhanced fibrinogen fractional synthesis rates (FSR) by 17 +/- 6% in the young and by 38 +/- 10% in the elderly participants compared with the water meal (P < 0.02). A comparable stimulation of FSR occurred with only the protein component of the meal in both young (29 +/- 7%) and elderly participants (41 +/- 9%) compared with the water meal (P < 0.005). Similar results were obtained when fibrinogen synthesis was expressed as absolute synthesis rates (i.e. mg.kg(-1).d(-1)). The results demonstrate that fibrinogen synthesis is acutely stimulated after ingestion of a meal and that this effect can be reproduced by the protein component of the meal alone, both in young and elderly adults.

Inflammation induces fibrinogen nitration in experimental human endotoxemia

Elevated plasma fibrinogen is a prothrombotic risk factor for cardiovascular disease (CVD). Recent small studies report that fibrinogen oxidative modifications, specifically tyrosine residue nitration, can occur in inflammatory states and may modify fibrinogen function. HDL cholesterol is inversely related to CVD and suggested to reduce the oxidation of LDL cholesterol, but whether these antioxidant functions extend to fibrinogen modifications is unknown. We used a recently validated ELISA to quantify nitrated fibrinogen during experimental human endotoxemia (N=23) and in a cohort of healthy adults (N=361) who were characterized for inflammatory and HDL parameters as well as subclinical atherosclerosis measures, carotid artery intima-medial thickness (IMT) and coronary artery calcification (CAC). Fibrinogen nitration increased following endotoxemia and directly correlated with accelerated ex vivo plasma clotting velocity. In the observational cohort, nitrated fibrinogen was associated with levels of CRP and serum amyloid A. Nitrated fibrinogen levels were not lower with increasing HDL cholesterol and did not associate with IMT and CAC. In humans, fibrinogen nitration was induced during inflammation and was correlated with markers of inflammation and clotting function but not HDL cholesterol or subclinical atherosclerosis in our modest sample. Inflammation-induced fibrinogen nitration may be a risk factor for promoting CVD events.

Hemostasis, inflammation, and fatal and nonfatal coronary heart disease: long-term follow-up of the atherosclerosis risk in communities (ARIC) cohort

OBJECTIVE

This study examines the hypothesis that chronic inflammation is associated with a higher risk of cardiac death compared to the risk of nonfatal myocardial infarction.

METHODS AND RESULTS

Cardiac death and nonfatal MI events were identified in the ARIC cohort during follow-up from 1987 through 2001. Markers of inflammation and hemostasis were determined at baseline using standardized procedures. Cox proportional hazard regression and polytomous logistic regression were used to estimate associations. We observed a positive gradient in incidence of sudden cardiac death (SCD), nonsudden cardiac death (NSCD), and nonfatal MI in association with decreasing levels of albumin and increasing levels of white blood cell count and of markers of hemostasis (fibrinogen, von Willebrand factor, factor VIIIc). Associations for von Willebrand factor were stronger for fatal relative to nonfatal events (3rd versus 1st tertile hazard ratios: SCD 3.11 [95% CI 2.10, 4.59], NSCD 2.12 [95% CI 1.28, 3.49], nonfatal MI 1.42 [95% CI 1.19, 1.70]). For factor VIIIc those associations were strongest for sudden cardiac death: SCD 3.16 (95% CI 2.18, 4.58), NSCD 1.44 (95% CI 0.93, 2.24), nonfatal MI 1.54 (95% CI 1.29, 1.84). Gradients of association for fibrinogen and white blood cell count, examined over tertiles of distribution and per one SD increase, were similar for the 3 end points. All associations were independent of smoking status.

CONCLUSIONS

von Willebrand factor and factor VIIIc are associated with an increased risk of cardiac death as compared to the risk of nonfatal MI.

Fibrinogen induces alterations of endothelial cell tight junction proteins

We previously showed that an elevated content of fibrinogen (Fg) increased formation of filamentous actin and enhanced endothelial layer permeability. In the present work we tested the hypothesis that Fg binding to endothelial cells (ECs) alters expression of actin-associated endothelial tight junction proteins (TJP). Rat cardiac microvascular ECs were grown in gold plated chambers of an electrical cell-substrate impedance system, 8-well chambered, or in 12-well plates. Confluent ECs were treated with Fg (2 or 4 mg/ml), Fg (4 mg/ml) with mitogen-activated protein kinase (MEK) kinase inhibitors (PD98059 or U0126), Fg (4 mg/ml) with anti-ICAM-1 antibody or BQ788 (endothelin type B receptor blocker), endothelin-1, endothelin-1 with BQ788, or medium alone for 24 h. Fg induced a dose-dependent decrease in EC junction integrity as determined by transendothelial electrical resistance (TEER). Western blot analysis and RT-PCR data showed that the higher dose of Fg decreased the contents of TJPs, occludin, zona occluden-1 (ZO-1), and zona occluden-2 (ZO-2) in ECs. Fg-induced decreases in contents of the TJPs were blocked by PD98059, U0126, or anti-ICAM-1 antibody. While BQ788 inhibited endothelin-1-induced decrease in TEER, it did not affect Fg-induced decrease in TEER. These data suggest that Fg increases EC layer permeability via the MEK kinase signaling pathway by affecting occludin, ZO-1, and ZO-2, TJPs, which are bound to actin filaments. Therefore, increased binding of Fg to its major EC receptor, ICAM-1, during cardiovascular diseases may increase microvascular permeability by altering the content and possibly subcellular localization of endothelial TJPs.

Circulating inflammatory and hemostatic biomarkers are associated with risk of myocardial infarction and coronary death, but not angina pectoris, in older men

AIMS

The extent to which hemostatic and inflammatory biomarkers are related to angina pectoris as compared with myocardial infarction (MI) remains uncertain. We examined the relationship between a wide range of inflammatory and hemostatic biomarkers, including markers of activated coagulation, fibrinolysis and endothelial dysfunction and viscosity, with incident myocardial infarction (MI) or coronary heart disease (CHD) death and incident angina pectoris uncomplicated by MI or CHD death in older men.

METHODS

A prospective study of 3217 men aged 60-79 years with no baseline CHD (angina or MI) and who were not on warfarin, followed up for 7 years during which there were 198 MI/CHD death cases and 220 incident uncomplicated angina cases.

RESULTS

Inflammatory biomarkers [C-reactive protein (CRP), interleukin-6, fibrinogen], plasma viscosity and hemostatic biomarkers [von Willebrand factor (VWF) and fibrin D-dimer] were associated with a significant increased risk of MI/CHD death but not with uncomplicated angina even after adjustment for age and conventional risk factors. Adjustment for CRP attenuated the relationships between VWF, fibrin D-dimer and plasma viscosity with MI/CHD death. Comparisons of differing associations with risk of MI/CHD deaths and uncomplicated angina were significant for the inflammatory markers (P < 0.05) and marginally significant for fibrin D-dimer (P = 0.05). In contrast, established risk factors including blood pressure and high-density lipoprotein (HDL)-cholesterol were associated with both MI/CHD death and uncomplicated angina.

CONCLUSION

Circulating biomarkers of inflammation and hemostasis are associated with incident MI/CHD death but not incident angina uncomplicated by MI or CHD death in older men.

Short-term effects of air pollution: a panel study of blood markers in patients with chronic pulmonary disease

Background

Growing evidence indicates that ambient air pollution is associated with exacerbation of chronic diseases like chronic pulmonary disease. A prospective panel study was conducted to investigate short-term changes of blood markers of inflammation and coagulation in response to daily changes in air pollution in Erfurt, Germany. 12 clinical visits were scheduled and blood parameters were measured in 38 male patients with chronic pulmonary disease during winter 2001/2002. Additive mixed models with random patient intercept were applied, adjusting for trend, weekday, and meteorological parameters. Hourly data on ultrafine particles (UFP, 0.01-0.1 μm), accumulation mode particles (ACP, 0.1-1.0 μm), PM₁₀ (particulate matter <10 μm in diameter), elemental (EC) and organic carbon (OC), gaseous pollutants (nitrogen monoxide [NO], nitrogen dioxide [NO₂], carbon monoxide [CO], and sulphur dioxide [SO₂]) were collected at a central monitoring site and meteorological data were received from an official network. For each person and visit the individual 24-hour average of pollutants immediately preceding the blood withdrawal (lag 0) up to day 5 (lag1-4) and 5-day running means were calculated.

Results

Increased levels of fibrinogen were observed for an increase in one interquartile range of UFP, PM₁₀, EC, OC, CO, and NO revealing the strongest effect for lag 3. E-selectin increased in association with ACP and PM₁₀ with a delay of one day. The ACP effect was also seen with the 5-day-mean. The pattern found for D-dimer was inconsistent. Prothrombin fragment 1+2 decreased with lag 4 consistently for all particulate pollutants. Von Willebrand factor antigen (vWF) showed a consistent decrease in association with almost all air pollutants with all lags except for lag 0. No associations were found for C-reactive protein, soluble intercellular adhesion molecule 1, serum amyloid A and factor VII.

Conclusion

These results suggest that elevated concentrations of air pollution are associated with changes in some blood markers of inflammation and coagulation in patients with chronic pulmonary disease. The clinical implications of these findings need further investigation.

Nighttime vagal cardiac control and plasma fibrinogen levels in a population of working men and women

BACKGROUND

Elevated plasma fibrinogen levels have prospectively been associated with an increased risk of coronary artery disease in different populations. Plasma fibrinogen is a measure of systemic inflammation crucially involved in atherosclerosis. The vagus nerve curtails inflammation via a cholinergic antiinflammatory pathway. We hypothesized that lower vagal control of the heart relates to higher plasma fibrinogen levels.

METHODS

Study participants were 559 employees (age 17-63 years; 89% men) of an airplane manufacturing plant in southern Germany. All subjects underwent medical examination, blood sampling, and 24-hour ambulatory heart rate recording while kept on their work routine. The root mean square of successive differences in RR intervals during the night period (nighttime RMSSD) was computed as the heart rate variability index of vagal function.

RESULTS

After controlling for demographic, lifestyle, and medical factors, nighttime RMSSD explained 1.7% (P = 0.001), 0.8% (P = 0.033), and 7.8% (P = 0.007), respectively, of the variance in fibrinogen levels in all subjects, men, and women. Nighttime RMSSD and fibrinogen levels were stronger correlated in women than in men. In all workers, men, and women, respectively, there was a mean +/- SEM increase of 0.41 +/- 0.13 mg/dL, 0.28 +/- 0.13 mg/dL, and 1.16 +/- 0.41 mg/dL fibrinogen for each millisecond decrease in nighttime RMSSD.

CONCLUSIONS

Reduced vagal outflow to the heart correlated with elevated plasma fibrinogen levels independent of the established cardiovascular risk factors. This relationship seemed comparably stronger in women than men. Such an autonomic mechanism might contribute to the atherosclerotic process and its thrombotic complications.

Emerging Risk Factors Collaboration, Erqou S, Kaptoge S, Perry PL, Di Angelantonio E, Thompson A, White IR, Marcovina SM, Collins R, Thompson SG, Danesh J. Lipoprotein(a) concentration and the risk of coronary heart disease, stroke, and nonvascular mortality

CONTEXT

Circulating concentration of lipoprotein(a) (Lp[a]), a large glycoprotein attached to a low-density lipoprotein-like particle, may be associated with risk of coronary heart disease (CHD) and stroke.

OBJECTIVE

To assess the relationship of Lp(a) concentration with risk of major vascular and nonvascular outcomes.

STUDY SELECTION

Long-term prospective studies that recorded Lp(a) concentration and subsequent major vascular morbidity and/or cause-specific mortality published between January 1970 and March 2009 were identified through electronic searches of MEDLINE and other databases, manual searches of reference lists, and discussion with collaborators.

DATA EXTRACTION

Individual records were provided for each of 126,634 participants in 36 prospective studies. During 1.3 million person-years of follow-up, 22,076 first-ever fatal or nonfatal vascular disease outcomes or nonvascular deaths were recorded, including 9336 CHD outcomes, 1903 ischemic strokes, 338 hemorrhagic strokes, 751 unclassified strokes, 1091 other vascular deaths, 8114 nonvascular deaths, and 242 deaths of unknown cause. Within-study regression analyses were adjusted for within-person variation and combined using meta-analysis. Analyses excluded participants with known preexisting CHD or stroke at baseline.

DATA SYNTHESIS

Lipoprotein(a) concentration was weakly correlated with several conventional vascular risk factors and it was highly consistent within individuals over several years. Associations of Lp(a) with CHD risk were broadly continuous in shape. In the 24 cohort studies, the rates of CHD in the top and bottom thirds of baseline Lp(a) distributions, respectively, were 5.6 (95% confidence interval [CI], 5.4-5.9) per 1000 person-years and 4.4 (95% CI, 4.2-4.6) per 1000 person-years. The risk ratio for CHD, adjusted for age and sex only, was 1.16 (95% CI, 1.11-1.22) per 3.5-fold higher usual Lp(a) concentration (ie, per 1 SD), and it was 1.13 (95% CI, 1.09-1.18) following further adjustment for lipids and other conventional risk factors. The corresponding adjusted risk ratios were 1.10 (95% CI, 1.02-1.18) for ischemic stroke, 1.01 (95% CI, 0.98-1.05) for the aggregate of nonvascular mortality, 1.00 (95% CI, 0.97-1.04) for cancer deaths, and 1.00 (95% CI, 0.95-1.06) for nonvascular deaths other than cancer.

CONCLUSION

Under a wide range of circumstances, there are continuous, independent, and modest associations of Lp(a) concentration with risk of CHD and stroke that appear exclusive to vascular outcomes.

Prognostic value of multiple biomarkers in American Indians free of clinically overt cardiovascular disease (from the Strong Heart Study)

Several biomarkers have been documented, singly or jointly, to improve risk prediction, but the extent to which they improve prediction-model performance in populations with high prevalences of obesity and diabetes has not been specifically examined. The aim of this study was to evaluate the ability of various biomarkers to improve prediction-model performance for death and major cardiovascular disease (CVD) events in a high-risk population. The relations of 6 biomarkers with outcomes were examined in 823 American Indians free of prevalent CVD or renal insufficiency, as were their contributions to risk prediction. In single-marker models adjusting for standard clinical and laboratory risk factors, 4 of 6 biomarkers significantly predicted mortality and major CVD events. In multimarker models, these 4 biomarkers-urinary albumin/creatinine ratio (UACR), glycosylated hemoglobin, B-type natriuretic peptide, and fibrinogen-significantly predicted mortality, while 2-UACR and fibrinogen-significantly predicted CVD. On the basis of its robust association in participants with diabetes, UACR was the strongest predictor of mortality and CVD, individually improving model discrimination or classification in the entire cohort. Singly, all remaining biomarkers also improved risk classification for mortality and enhanced average sensitivity for mortality and CVD. The addition of > or =1 biomarker to the single marker UACR further improved discrimination or average sensitivity for these outcomes. In conclusion, biomarkers derived from diabetic cohorts, and novel biomarkers evaluated primarily in lower risk populations, improve risk prediction in cohorts with prevalent obesity and diabetes. Risk stratification of these populations with multimarker models could enhance selection for aggressive medical or surgical approaches to prevention.

Biomarkers of premature atherosclerosis

C-reactive protein (CRP) is an acute phase protein and a biochemical marker with important prognostic value for cardiovascular events. Interleukins IL-1 and IL-6 are implicated in the pathogenesis of atherosclerosis and are associated with CRP. Apolipoproteins ApoA-I and ApoB are the main lipid metabolic markers implicated in the development and progression of atherosclerosis. Fibrinogen has also been proposed to be a major independent risk factor for cardiovascular events. Because premature atherosclerosis precedes the development of cardiovascular disease, identification of the associated biomarkers is of great importance. However, further studies will be needed to determine whether or not these markers are useful predictors of future cardiovascular events. Here, we review the roles of specific biomarkers that have been implicated in premature atherosclerosis.

Diabetes mellitus and cerebrovascular disease: which are the actual data?

Cerebrovascular disease (CeVD) represents a major cause of morbidity and mortality worldwide. Diabetes mellitus (DM) represents an independent risk factor for CeVD. The aim of the present review is to describe the epidemiology of CeVD in patients with DM and to explain how DM and diabetic autonomic neuropathy can increase the risk of CeVD. The prevention and management of CeVD in the diabetic population are also analyzed.

Changes in inflammatory biomarkers across weight classes in a representative US population: a link between obesity and inflammation

BACKGROUND

Obesity has been linked with a chronic state of inflammation which may be involved in the development of metabolic syndrome, cardiovascular disease, non-alcoholic steatohepatitis, and even cancer. The objective of this study was to examine the association between obesity class and levels of inflammatory biomarkers from men and women who participated in the 1999-2004 National Health and Nutrition Examination Survey (NHANES).

METHODS

Serum concentrations of C-reactive protein (CRP) and fibrinogen were measured among US participants of the 1999-2004 NHANES. We examined biomarker levels across different weight classes with normal weight, overweight, and obesity classes 1, 2, and 3 were defined as BMI of < 25.0, 25.0-29.9, 30.0-34.9, 35.0-39.9, and > or = 40.0, respectively.

RESULTS

With CRP levels for normal weight individuals as a reference, CRP levels nearly doubled with each increase in weight class: +0.11 mg/dl (95% CI, 0.06-0.16) for overweight, +0.21 mg/dl (95% CI, 0.16-0.27) for obesity class 1, +0.43 mg/dl (95% CI, 0.26-0.61) for obesity class 2, and +0.73 mg/dl (95% CI, 0.55-0.90) for obesity class 3. With normal weight individuals as a reference, fibrinogen levels increase with increasing weight class and were highest for obesity class 3 individuals, +93.5 mg/dl (95% CI, 72.9-114.1). Individuals with hypertension or diabetes have higher levels of CRP and fibrinogen levels compared to individuals without hypertension or diabetes, even when stratified according to BMI.

CONCLUSIONS

There is a direct association between increasing obesity class and the presence of obesity-related comorbidities such as diabetes and hypertension with high levels of inflammatory biomarkers.

Are markers of inflammation more strongly associated with risk for fatal than for nonfatal vascular events?

BACKGROUND

Circulating inflammatory markers may more strongly relate to risk of fatal versus nonfatal cardiovascular disease (CVD) events, but robust prospective evidence is lacking. We tested whether interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen more strongly associate with fatal compared to nonfatal myocardial infarction (MI) and stroke.

METHODS AND FINDINGS

In the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), baseline inflammatory markers in up to 5,680 men and women aged 70-82 y were related to risk for endpoints; nonfatal CVD (i.e., nonfatal MI and nonfatal stroke [n = 672]), fatal CVD (n = 190), death from other CV causes (n = 38), and non-CVD mortality (n = 300), over 3.2-y follow-up. Elevations in baseline IL-6 levels were significantly (p = 0.0009; competing risks model analysis) more strongly associated with fatal CVD (hazard ratio [HR] for 1 log unit increase in IL-6 1.75, 95% confidence interval [CI] 1.44-2.12) than with risk of nonfatal CVD (1.17, 95% CI 1.04-1.31), in analyses adjusted for treatment allocation. The findings were consistent in a fully adjusted model. These broad trends were similar for CRP and, to a lesser extent, for fibrinogen. The results were also similar in placebo and statin recipients (i.e., no interaction). The C-statistic for fatal CVD using traditional risk factors was significantly (+0.017; p<0.0001) improved by inclusion of IL-6 but not so for nonfatal CVD events (p = 0.20).

CONCLUSIONS

In PROSPER, inflammatory markers, in particular IL-6 and CRP, are more strongly associated with risk of fatal vascular events than nonfatal vascular events. These novel observations may have important implications for better understanding aetiology of CVD mortality, and have potential clinical relevance.