Michael W. Mansfield

Altered Fibrin Clot Structure in the Healthy Relatives of Patients With Premature Coronary Artery Disease

Background—A family history of premature coronary artery disease (CAD) is an independent cardiovascular risk factor. Fibrin clots composed of dense fiber networks are found in young CAD patients and may occur in the relatives of such individuals. Methods and Results—The ex vivo fibrin structure of 100 healthy male relatives of patients with premature CAD and 100 age-matched control subjects was assessed by measurement of permeability (Ks), fiber mass-length ratio (&mgr;), and turbidity (lag phase and maximum absorbency [max &Dgr;Abs]). Scanning electron microscopy was performed on selected samples. Relatives and controls shared similar levels of conventional cardiovascular risk factors. Ks was lower in relatives than in controls, 12.2 (11.1 to 13.3) versus 15.2 (14.0 to 16.5) ×10−9 cm2 (P <0.001), associated with a smaller decrease in &mgr;, 8.5 (7.7 to 9.2) versus 9.7 (8.9 to 10.5) × 1013 Da/cm (P <0.05), respectively. Lag phase was shorter in relatives than in controls, 39 (37 to 41) versus 47 (44 to 50) seconds (P <0.001), and max &Dgr;Abs was higher in relatives, 0.78 (0.74 to 0.82) versus 0.71 (0.67 to 0.74) in controls (P =0.02), which indicates the presence of thicker fibers in relatives. After adjustment for fibrinogen levels, lag phase and Ks remained significantly different between relatives and control subjects. Scanning electron microscopy images confirmed increased fiber diameter in relatives, possibly of reduced density. Factor XIII Val34Leu and fibrinogen A&agr; Thr312Ala and B&bgr; -455 G/A showed no association with clot structure. Conclusions—The male relatives of patients with premature CAD form fibrin clots that begin polymerization more quickly, have thicker fibers, and are less permeable than those of control subjects.

Plasminogen Activator Inhibitor-1 Promoter 4G/5G Genotype and Plasma Levels in Relation to a History of Myocardial Infarction in Patients Characterized by Coronary Angiography

To investigate the relationship between an insertion/deletion (4G/5G) polymorphism in the promoter region of the plasminogen activator inhibitor-1 (PAI-1) gene and the phenotypes of PAI-1 levels, coronary atheroma, and a past history of coronary thrombosis, we studied 453 patients (320 men and 133 women) characterized by coronary angiography. Patients were classified as having normal vessels (n = 125) or single-vessel (n = 92) or multivessel (n = 232) coronary disease on the basis of > or = 50% stenosis. PAI-1 antigen levels were highest in patients with the 4G/4G genotype (22.5 ng/mL), with a stepwise decrease in levels as the number of 4G alleles decreased (21.5 ng/mL for 4G/5G and 15.8 ng/mL for 5G/5G, P = .02) after adjusting for age, sex, triglyceride levels, and body mass index (BMI). The association between triglyceride level and PAI-1 was genotype specific, with a steeper slope in subjects with the 4G/4G genotype (P = .004). A gene-environment interaction between BMI, PAI-1, and genotype was observed, with a steeper association in patients with the 5G/5G genotype (P = .02). The 4G/4G genotype was significantly associated with a history of myocardial infarction (P < .03; odds ratio, 2.0; 95% CI, 1.1 to 3.7). This relationship was stronger in subjects with diseased vessels (P = .006). There was no relationship between either PAI-1 genotype or levels and the presence of atheroma. Our data suggest that PAI-1 promoter polymorphism influences the development of myocardial infarction through its effect on thrombus formation in patients with preexisting coronary atheroma.

Predictive Variables for Mortality After Acute Ischemic Stroke

Background and Purpose— Stroke is a major healthcare issue worldwide with an incidence comparable to coronary events, highlighting the importance of understanding risk factors for stroke and subsequent mortality. Methods— In the present study, we determined long-term (all-cause) mortality in 545 patients with ischemic stroke compared with a cohort of 330 age-matched healthy control subjects followed up for a median of 7.4 years. We assessed the effect of selected demographic, clinical, biochemical, hematologic, and hemostatic factors on mortality in patients with ischemic stroke. Stroke subtype was classified according to the Oxfordshire Community Stroke Project criteria. Patients who died 30 days or less after the acute event (n=32) were excluded from analyses because this outcome is considered to be directly attributable to the acute event. Results— Patients with ischemic stroke were at more than 3-fold increased risk of death compared with the age-matched control cohort. In multivariate analyses, age, stroke subtype, atrial fibrillation, and previous stroke/transient ischemic attack were predictive of mortality in patients with ischemic stroke. Albumin and creatinine and the hemostatic factors von Willebrand factor and &bgr;-thromboglobulin were also predictive of mortality in patients with ischemic stroke after accounting for demographic and clinical variables. Conclusions— The results indicate that subjects with acute ischemic stroke are at increased risk of all-cause mortality. Advancing age, large-vessel stroke, atrial fibrillation, and previous stroke/transient ischemic attack predict mortality; and analysis of albumin, creatinine, von Willebrand factor, and &bgr;-thromboglobulin will aid in the identification of patients at increased risk of death after stroke.

Heritability of features of the insulin resistance syndrome in a community‐based study of healthy families

Aims To investigate genetic and environmental influences on anthropometric, metabolic and fibrinolytic traits of the insulin resistance syndrome (IRS) in a population not characterized by a high degree of insulin resistance.

Circulating Levels of Factor VII, Fibrinogen, and von Willebrand Factor and Features of Insulin Resistance in First-Degree Relatives of Patients With NIDDM

BACKGROUND First-degree relatives of patients with non-insulin-dependent diabetes mellitus (NIDDM) have an increased risk of coronary artery disease partly attributable to clustering of risk factors in association with insulin resistance. Circulating levels of some hemostatic factors predict coronary events, and there is growing evidence that insulin resistance is also associated with abnormalities of coagulation and fibrinolysis. This study examined the hypotheses that elevated levels of factor VII coagulant activity (FVII:C), fibrinogen, and von Willebrand factor (vWF) occur (1) in first-degree relatives of NIDDM patients and (2) in association with recognized features of insulin resistance. METHODS AND RESULTS Fasting blood samples were taken from 132 first-degree relatives of NIDDM patients and 151 age matched control subjects for measurement of FVII:C, fibrinogen, vWF, insulin, total and HDL cholesterol, triglyceride, glucose, and HbAIC. Levels of FVII:C (130% versus 122%, P < .02) and fibrinogen (3.0 versus 2.7 g/L, P = .002) were higher in relatives than in control subjects, and there was no significant difference in levels of vWF (0.98 versus 0.95 IU/mL). There was a graded association with features of insulin resistance, which was strongest for FVII:C, weaker for fibrinogen, and weakest for vWF. CONCLUSIONS FVII:C and fibrinogen levels are increased in relatives of patients with NIDDM. Levels of FVII:C and, to a lesser extent, fibrinogen and vWF cluster with other risk factors associated with insulin resistance. Abnormalities of circulating hemostatic factors, possibly in relation to insulin resistance, may contribute to cardiovascular risk in relatives of patients with NIDDM.

Subunit Antigen and Activity Levels of Blood Coagulation Factor XIII in Healthy Individuals: Relation to Sex, Age, Smoking, and Hypertension

Factor (F) XIII covalently cross-links and stabilizes the fibrin-clot. Recent evidence suggests a role for FXIII in atherothrombotic diseases, but no information is available regarding the association of FXIII with common risk factors. The aim of this study was to investigate the relationship of FXIII with age, sex, smoking, and hypertension. Plasma levels of FXIII A-subunit antigen, FXIII B-subunit antigen, and FXIII cross-linking activity were measured in 612 healthy individuals (250 men and 362 women). FXIII A- and B-subunit levels were correlated significantly with age in both men (r=0.21, P=0.001, and r=0.17, P=0.008, respectively) and women (r=0.20, P<0.0005, and r=0.13, P=0.011, respectively). FXIII B-subunit levels and activity were correlated significantly with FXIII A-subunit levels (r=0.60, P<0.0005, and r=0.14, P<0.0005, respectively) and fibrinogen (r=0.26, P<0.0005, and r=0.14, P=0.001, respectively). Women had higher levels of FXIII A-subunit (111.8% versus 105.2%, P<0.01) and B-subunit (109.5% versus 103.8%, P<0.01) than did men. FXIII A-subunit was significantly increased in smokers (117.0% versus 104.6%, P<0.0005) and in subjects with hypertension (114.9% versus 107.8%, P<0.05). In a multiple regression model, FXIII A-subunit was significantly increased by female sex (+6.4%, P<0.007), smoking (+12.3%, P<0.0005), and increasing age (+3.7% per 10 years, P<0.0005). FXIII B-subunit was significantly related to female sex and fibrinogen, and FXIII activity was significantly related to fibrinogen levels. In conclusion, the FXIII A-subunit level increases significantly with female sex, age, and smoking, whereas FXIII B-subunit and FXIII activity are associated with FXIII A-subunit level and fibrinogen. Although evidence for a causal relationship between FXIII A-subunit and vascular disease is not available, these results might suggest a role for elevated FXIII A-subunit levels in the pathogenesis of vascular disease.

Soluble vascular cell adhesion molecule-1 and E-selectin levels in relation to vascular risk factors and to E-selectin genotype in the first degree relatives of NIDDM patients and in NIDDM patients

Summary To investigate the metabolic and genetic associations of levels of soluble adhesion molecules, plasma levels of soluble E-selectin and vascular cell adhesion molecule-1 were measured in 60 non-insulin-dependent diabetes mellitus (NIDDM) patients, 60 first-degree relatives of NIDDM patients and 60 control subjects, none of whom displayed clinical features of vascular disease. In addition, E-selectin A561C genotype, coding for a serine to arginine change, was determined. E-selectin levels were elevated in the patient group; 57 [52–63] (mean [95 % confidence intervals]) ng/ml, compared with both relatives; 44 [39–50] ng/ml p = 0.001 and controls 39.5 [36–43] ng/ml p = 0.0001. E-selectin levels correlated with triglycerides, tissue-plasminogen activator and plasminogen activator inhibitor-1 activity in all groups. Levels of E-selectin were related to E-selectin genotype, being higher in subjects possessing the arginine allele (51.4 vs 44.5 ng/ml p < 0.05). E-selectin levels were higher in males than females in controls (female 35 [32–39] vs male 45 [40–51] ng/ml p = 0.004), and NIDDM relatives (female 38 [33–44] vs male 52 [45–61] ng/ml p = 0.004) but not in NIDDM patients where levels were similar (female 58 [49–69] vs male 56 [50–62] ng/ml, ns). There was no difference in soluble vascular cell adhesion molecule-1 levels between the three groups (control 640 [598–686] ng/ml, NIDDM relatives 634 [593–678] ng/ml and NIDDM patients 664 [608–725] ng/ml). In controls and patients vascular cell adhesion molecule-1 levels correlated with von Willebrand factor (vWF). The results indicate that levels of E-selectin relate to vascular risk factors in control subjects, NIDDM relatives and NIDDM patients. [Diabetologia (1998) 41: 460–466]

β-fibrinogen gene −455 G/A Polymorphism and Fibrinogen Levels: Risk factors for coronary artery disease in subjects with NIDDM

OBJECTIVE To investigate the association of a G/A polymorphism at position −455 of the β-fibrinogen gene and fibrinogen levels in the development of coronary artery disease (CAD) in subjects with NIDDM. RESEARCH DESIGN AND METHODS In 187 Caucasian subjects with NIDDM, presence of CAD was taken as a clinical history of angina, myocardial infarction, coronary angioplasty, or coronary artery bypass grafting, confirmed from medical case notes. RESULTS Fibrinogen levels were significantly higher in subjects with CAD (n = 38, 3.41 [3.12–3.73] g/l) than those without (n = 149, 2.99 [2.87–3.11] g/l, P = 0.004 [geometric mean, 95% CI]). Comparing the genotype frequencies by X2 testing, there was a significant difference between subjects with CAD (GG = 0.84, GA + AA = 0.16) and those without (GG = 0.64, GA + AA = 0.36, P = 0.02). In a logistic regression model, including age, BMI, cholesterol, sex, smoking, triglycerides, and plasminogen activator inhibitor antigen as covariates, genotype and fibrinogen levels were significantly associated with CAD. The odds ratio for having CAD in individuals homozygous for the G allele compared with those possessing the A allele was 1.77 (1.08−2.90), P = 0.03; and for an increase of 1 g/l in fibrinogen levels was 1.60 (1.00–2.60), P = 0.05. CONCLUSIONS These data suggest a relationship between the −455 G/A β-fibrinogen gene polymorphism and the development of CAD in subjects with NIDDM. This relationship was not associated with variations in fibrinogen levels, suggesting that this polymorphism may be in linkage with a polymorphism within the coding region of the β-fibrinogen gene, which results in an alteration in the stability of the fibrin clot.

Apolipoprotein E polymorphism in cerebrovascular disease

Objectives– The aim of this study was to investigate the relationship between the apo E genotype with acute cerebral infarction and primary intracerebral haemorrhage and to examine the relationship of the apo E genotype with mortality following acute stroke. Materials and methods– We studied 592 cases of acute stroke and 289 healthy control subjects clinically free of cerebrovascular disease. Pathological type of stroke was determined by cranial computed tomography and the subtype of cerebral infarction classified according to the Oxfordshire Community Stroke Project Classification (OCSP). Apo E genotype was determined using polymerase chain reaction. Results– There was no difference in apo E genotype frequency between cases and controls (ξ2=3.58, 5 d.f., P=0.60). Apo E genotypes were not related to the pathological type of stroke (cerebral infarction, CI, n=532 and primary intracranial haemorrhage, PICH, n=60, (ξ2=3.738, 4 d.f., P=0.44) nor with the Oxfordshire Community Stroke Project Classification subtypes of cerebral infarction, lacunar infarction, LACI (n=169), total anterior circulation infarction, TACI (n=117), partial anterior circulation infarction, PACI (n=173), posterior circulation infarction, POCS (n=54) and including those cerebral infarcts which could not be classified (n=19), ξ2=31.1, 20 d.f., P=0.153). At the time of the analysis, 243 cases (41.0%) had died. The median follow‐up (including death) was 851 days. There was no relationship between time to death and apo E genotype in cases of either CI or PICH. Conclusion– In this population, there was no relationship between the apolipoprotein E polymorphism and the pathogenesis of cerebral infarction or primary intracerebral haemorrhage. Apo E genotype was not related to all‐cause mortality following stroke.

Soluble P‐selectin levels, P‐selectin polymorphisms and cardiovascular disease

Summary.  P‐selectin is a member of the selectin family of cell adhesion molecules which are important in the transient attachment of leukocytes to endothelial cells and platelets. A number of polymorphisms in the gene encoding P‐selectin have been identified. Objectives were to investigate the relationship of soluble P (sP)‐selectin with P‐selectin gene polymorphisms and coronary artery disease (CAD). Two hundred and forty‐nine patients, with extent of CAD characterized by ≥50% stenosis in one or more coronary arteries, and 252 healthy controls were studied. Soluble P‐selectin was significantly higher in the patients than controls after adjustment for age, sex and smoking [patients 49.8 (47.5–52.1) ng mL−1; controls 46.7 (44.5–49.1) ng mL−1, P = 0.03). There was no association of sP‐selectin with myocardial infarction (MI) or presence of ≥50% stenosis. The −1817 T/C, −1969 G/A and −2123 C/G (but not the Thr715Pro) polymorphisms were in strong linkage disequilibrium. The Thr715Pro polymorphism was significantly associated with sP‐selectin even after adjustment for covariates [TT 48.9 (46.9–50.0) ng mL−1; TP + PP 40.7 (38.1–43.6) ng mL−1, P < 0.0001]. A significant interaction of Thr715Pro and smoking status was identified in the determination of sP‐selectin levels. There was no significant association of genotype at any of the polymorphism in relation to MI or stenosis. The Thr715Pro polymorphisms is associated with plasma sP‐selectin. This association is modulated by smoking, although the underlying mechanism remains unclear.