Coagulation, fibrinolysis and cardiovascular disease

Development of a Hypercoagulable-Hypofibrinolytic State Early After Spinal Cord Injury

OBJECTIVES

To determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes.

DESIGN

Cross-sectional study.

SETTING

Neurorehabilitation hospital and general community.

PARTICIPANTS

Thirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Circulating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay.

RESULTS

Thirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults.

CONCLUSIONS

Subacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI.

Cardiovascular Risk Stratification Based on Oxidative Stress for Early Detection of Pathology

Aims: Current cardiovascular (CV) risk prediction algorithms are able to quantify the individual risk of CV disease. However, CV risk in young adults is underestimated due to the high dependency of age in biomarker-based algorithms. Because oxidative stress is associated with CV disease, we sought to examine CV risk stratification in young adults based on oxidative stress to approach the discovery of new markers for early detection of pathology. Results: Young adults were stratified into (i) healthy controls, (ii) subjects with CV risk factors, and (iii) patients with a reported CV event. Plasma samples were analyzed using FASILOX, a novel approach to interrogate the dynamic thiol redox proteome. We also analyzed irreversible oxidation by targeted searches using the Uniprot database. Irreversible oxidation of cysteine (Cys) residues was greater in patients with reported CV events than in healthy subjects. These results also indicate that oxidation is progressive. Moreover, we found that glutathione reductase and glutaredoxin 1 proteins are differentially expressed between groups and are proteins involved in antioxidant response, which is in line with the impaired redox homeostasis in CV disease. Innovation: This study, for the first time, describes the oxidative stress (reversible and irreversible Cys oxidation) implication in human plasma according to CV risk stratification. Conclusion: The identification of redox targets and the quantification of protein and oxidative changes might help to better understand the role of oxidative stress in CV disease, and aid stratification for CV events beyond traditional prognostic and diagnostic markers. Antioxid. Redox Signal. 35, 602-617.

Association of electrocardiographic left ventricular hypertrophy with incident cardiovascular disease in Japanese older hypertensive patients

BACKGROUND

Our aim was to assess whether electrocardiographic left ventricular hypertrophy (ECG-LVH) is associated with a higher risk of cardiovascular disease (CVD) events, independent of 24-hour blood pressure (BP) and circulating levels of norepinephrine and hemostatic factors.

METHODS

In 514 older hypertensive patients (mean age 72.3 years; 37% men), we assessed ambulatory BP values, circulating levels of norepinephrine and hemostatic factors (plasma fibrinogen, prothrombin fragment 1+2 (F1+2), von Willebrand factor (vWF), and plasminogen activator inhibitor-1 (PAI-1)), and the presence or absence of ECG-LVH (Sokolow-Lyon voltage ≥ 3.5 mV). The incidence of CVD events (i.e., myocardial infarction and stroke) was prospectively ascertained.

RESULTS

During an average 41 months of follow-up (1,751 person-years), 43 stroke and 3 myocardial infarction events occurred. At baseline, patients with ECG-LVH had higher mean 24-hour BP (148.8/83.8mm Hg vs. 135.7/77.2mm Hg) and circulating norepinephrine levels (404.6 pg/ml vs. 336.3 pg/ml) compared to those without ECG-LVH; the differences remained unchanged after adjustment for age, gender, smoking status, presence of diabetes, and antihypertensive medication uses at follow-up time (all P < 0.01). Cox proportional hazards models suggested that the hazard ratio (HR; 95% confidence interval (CI)) of CVD events for those with ECG-LVH was 4.4 (2.3-8.2), and the association between ECG-LVH and incident CVD events remained significant after adjustment for high 24-hour BP (≥130/80mm Hg), nocturnal SBP, circulating norepinephrine and fibrinogen levels (HRs, 3.5-4.2, all P < 0.001).

CONCLUSIONS

In older hypertensive patients, ECG-LVH was associated with a higher risk of CVD events, independent of ambulatory BP parameters and circulating norepinephrine and fibrinogen levels.

Plasma hemostatic factors and endothelial markers in four racial/ethnic groups: the MESA study

BACKGROUND

Hemostatic factors and endothelial markers may play some role in racial/ethnic differences in cardiovascular disease (CVD) rates. However, little information exists on hemostatic factors and endothelial markers across racial/ethnic groups.

OBJECTIVES

To describe, in four American racial/ethnic groups (Caucasian, Black, Hispanic, and Chinese), mean levels of selected hemostatic factors and endothelial markers.

PATIENTS AND METHODS

Multi-ethnic Study of Atherosclerosis baseline data were used (participant age: 45-84 years). Sex-specific analysis of covariance models, and t-tests for pairwise comparisons, were used to compare means of factors and markers. Adjustments were made for demographics and traditional CVD risk factors. Differences were significant at P < 0.05.

RESULTS

Blacks had the highest levels of factor VIII, D-Dimer, plasmin-antiplasmin (PAP), and von Willebrand factor, among the highest levels of fibrinogen and E-selectin (women only), but among the lowest levels of intercellular adhesion molecule 1 (ICAM-1), and, in men, the lowest levels of plasminogen activator inhibitor-1 (PAI-1). Whites and Hispanics tended to have intermediate levels of factors and markers, although they had the highest levels of ICAM-1, and Hispanics had the highest mean levels of fibrinogen and E-selectin (women only). Chinese participants had among the highest levels of PAI-1, but the lowest, or among the lowest, of all other factors and markers. No soluble thrombomodulin differences were observed.

CONCLUSIONS

In this large cohort, hemostatic factor and endothelial marker mean levels varied by race/ethnicity, even after adjustment for traditional CVD risk factors.

Lowering of blood pressure leads to decreased circulating interleukin-6 in hypertensive subjects

Interleukin-6 (IL-6), the major proinflammatory cytokine, has been described to be associated with the hypertensive and atherosclerotic states. We aimed to explore whether the concentration of circulating IL-6 and adhesion molecules could be modified by decreasing blood pressure in hypertensive subjects. A total of 30 subjects (18 men), aged 34-48 years, were enrolled in this study, 17 hypertensive never-treated patients (HTA) and 13 normotensive subjects (C). HTA subjects were treated with irbesartan, 150-300 mg/day for 3 months, and serum IL-6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, sP-selectin, sE-selectin and monocyte chemoattractant protein-1 were measured at 0 and 12 weeks. The two study groups were similar in age, body mass index (BMI) and gender. At baseline, circulating IL-6 levels, but not adhesion molecules, were significantly associated with systolic blood pressure (r=0.41; P=0.03) and BMI (r=0.53; P=0.005). Systolic and diastolic blood pressure decreased significantly (P<0.01) in parallel to serum IL-6 levels (from 3.72+/-0.82 to 3.23+/-0.19 pg/ml, P=0.02) reaching a similar concentration to normotensive patients (3.33+/-0.3 pg/ml) after treatment with irbesartan. No significant changes were observed in any other of the tested parameters. In conclusion, the treatment of high blood pressure lowers circulating IL-6 in young hypertensive patients.

Insulin resistance and chronic cardiovascular inflammatory syndrome

Insulin resistance is increasingly recognized as a chronic, low-level, inflammatory state. Hyperinsulinemia and insulin action were initially proposed as the common preceding factors of hypertension, low high-density lipoprotein cholesterol, hypertriglyceridemia, abdominal obesity, and altered glucose tolerance, linking all these abnormalities to the development of coronary heart disease. The similarities of insulin resistance with another inflammatory state, atherosclerosis, have been described only in the last few decades. Atherosclerosis and insulin resistance share similar pathophysiological mechanisms, mainly due to the actions of the two major proinflammatory cytokines, TNF-alpha and IL-6. Genetic predisposition to increased transcription rates of these cytokines is associated with metabolic derangement and simultaneously with coronary heart disease. Dysregulation of the inflammatory axis predicts the development of insulin resistance and type 2 diabetes mellitus. The knowledge of how interactions between metabolic and inflammatory pathways occur will be useful in future therapeutic strategies. The effective administration of antiinflammatory agents in the treatment of insulin resistance and atherosclerosis is only the beginning of a promising approach in the management of these syndromes.

The molecular genetics of cardiovascular disease: clinical implications

Coronary heart disease (CHD) is one of the main leading causes of death worldwide. CHD is a complex condition resulting from numerous gene-gene and gene-environment interactions. A large number of candidate genes exist. We review the evidence for the role of apolipoprotein E, lipoprotein lipase and interleukin-6 in CHD and their interaction with smoking (an environmental risk). The main objective of genetic research into CHD is to provide a complete risk assessment, complementing the well-studied traditional clinical and biochemical risk factors. Unravelling the role that functional gene polymorphisms play in determining risk, and in determining the levels of intermediate phenotypes is crucial to our understanding of the key metabolic pathways and physiology not only in the diseased, but also in the disease-free state. The identification of new molecules (implicated in the relevant metabolic pathways) may subsequently lead to potential targets for therapeutic intervention. Improving our molecular understanding may also lead to the development of improved diagnostics. Sequencing of the entire genome is now a reality. Advances in technology, such as the development of "gene chips" may allow us to study 100 000 genes at a time on a single chip. Such advances will amplify the power available to us in the realms of research into genetic physiology and interaction with environmental stimuli. The insights that these novel approaches may yield are eagerly awaited.

The -174 G/C polymorphism of the interleukin-6 gene promoter and essential hypertension in an elderly Italian population

Several studies have proposed a relationship between blood pressure and inflammation. Interleukin-6 (IL-6) is a multifunctional cytokine involved in inflammation and tissue injury and potentially influencing blood pressure. Recently, a common polymorphism of the IL-6 gene, associated with differences in the transcription rate of the protein, has been described. The aim of this study was to investigate a possible association between genetic variations of the -174GC polymorphism of the IL-6 gene promoter and hypertension in humans. IL-6 gene promoter polymorphism was evaluated by polymerase chain reaction followed by restriction enzyme analysis in 210 elderly Italian patients affected by essential hypertension (EH) and 177 age- and sex-matched controls. The distribution of IL-6 genotypes was 85 GG, 88 GC, 37 CC in the hypertensive patients and 65 GG, 73 GC, 39 CC in the control subjects. In this elderly cohort, no statistically significant association was found between the two groups (P = 0.45 for GG homozygous, P = 0.89 for GC heterozygous and P = 0.27 for CC homozygous). In conclusion the -174 GC polymorphism of the IL-6 gene promoter is not a marker for EH in this sample of elderly Italians.

Fats, lipids and blood coagulation

Saturated and n-3 fatty acids, postprandial lipaemia, and the combined effects of fatty acids and lipid-lowering drugs have been of principal interest in recent studies in the field of dietary fats, lipids and haemostasis. The sex-specific effect of individual saturated fatty acids on coagulation factor VII activity has been discovered, and the significant effect of factor VII R353Q polymorphism on the postprandial response has also been found. An increased intake of n-3 fatty acids or fat reduction when combined with intensive lifestyle interventions may lead to reduced thrombotic potential in type 2 diabetic patients and obese individuals. Furthermore, positive effects on haemostasis by combined treatment with long-chain n-3 fatty acids and simvastatin indicate that n-3 fatty acids may be of some relevance with lipid-lowering drugs. The possible unfavourable effect of n-3 fatty acids on plasminogen activator inhibitor-1 activity is still a matter of dispute, but recent studies suggest that n-3 fatty acids, including alpha-linolenic acid, may have antithrombotic effects by enhancing protein C activity.