Plasma levels of von willebrand factor, endothelin-1, prostacyclin and thromboxane in children from families with high risk of premature coronary artery disease

Transition in the mechanism of flow-mediated dilation with aging and development of coronary artery disease

In microvessels of patients with coronary artery disease (CAD), flow-mediated dilation (FMD) is largely dependent upon the endothelium-derived hyperpolarizing factor H₂O₂. The goal of this study is to examine the influence of age and presence or absence of disease on the mechanism of FMD. Human coronary or adipose arterioles (~150 µm diameter) were prepared for videomicroscopy. The effect of inhibiting COX [indomethacin (Indo) or NOS (L-NAME), eliminating H₂O₂ (polyethylene glycol-catalase (PEG-CAT)] or targeting a reduction in mitochondrial ROS with scavengers/inhibitors [Vitamin E (_mtVitamin E); phenylboronic acid (_mtPBA)] was determined in children aged 0-18 years; young adults 19-55 years; older adults >55 years without CAD, and similarly aged adults with CAD. Indo eliminated FMD in children and reduced FMD in younger adults. This response was mediated mainly by PGI₂, as the prostacyclin-synthase-inhibitor trans-2-phenyl cyclopropylamine reduced FMD in children and young adults. L-NAME attenuated dilation in children and younger adults and eliminated FMD in older adults without CAD, but had no effect on vessels from those with CAD, where mitochondria-derived H₂O₂ was the primary mediator. The magnitude of dilation was reduced in older compared to younger adults independent of CAD. Exogenous treatment with a sub-dilator dose of NO blocked FMD in vessels from subjects with CAD, while prolonged inhibition of NOS in young adults resulted in a phenotype similar to that observed in disease. The mediator of coronary arteriolar FMD evolves throughout life from prostacyclin in youth, to NO in adulthood. With the onset of CAD, NO-inhibitable release of H₂O₂ emerges as the exclusive mediator of FMD. These findings have implications for use of pharmacological agents, such as nonsteroidal anti-inflammatory agents in children and the role of microvascular endothelium in cardiovascular health.

Diabese youngsters have 3.7 more chances in developing metabolic syndrome compared with the obese

BACKGROUND AND AIMS

Diabesity, the coexistence of diabetes and obesity, is a new health epidemic. The present case-control study aimed in assessing the prevalence of metabolic syndrome (MS) between diabese and obese children and adolescents.

METHODS AND RESULTS

One-hundred and fifty-four obese children and adolescents aged 4-16 yr were recruited and divided in 2 groups: the diabese (no.=85) who were diagnosed with obesity and impaired glucose tolerance (IGT) and the obese (no.=69), who formed the controls group and did not demonstrate IGT. Von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), and uric-acid levels were measured. Being diabese increased the odds ratio (OR) for developing MS (OR: 3.714), demonstrating increased serum triglycerides (TG) (OR: 9.067) and low HDL-cholesterol (HDL-C) (OR: 1.405), developing hypertension (OR: 0.750) and acanthosis nigricans (OR: 2.882). In the total sample, low HDL-C was the most common MS criterion, diagnosed in 68% of the diabese and 62% of the obese subjects. Age and weight-adjustment of the continuous data demonstrated that the diabese subjects had higher fat mass index, blood pressure, and TG levels, however the obese exhibited lower HDLC concentrations. Principal component analysis demonstrated that among the inflammatory biomarkers PAI-1 and vWF contributed to the prevalence of MS.

CONCLUSION

The present study is the first to demonstrate that the diabese youngsters have 3.7 times more chances in developing MS compared with the obese. From the examined atherosclerotic biomarkers, PAI-1 and vWF contributed to the prevalence of the syndrome and both indicate the initiation of endothelial dysfunction.

Relationship between plasma cholesterol, von Willebrand factor concentrations, extent of atherosclerosis and antibody titres to heat shock proteins-60, -65 and -70 in cholesterol-fed rabbits

Epidemiological studies have shown an association between atherosclerosis, Heat shock protein (Hsp) expression, and Hsp antibody titres. We aimed to investigate the time course of appearance of Hsp-60, -65 and -70 antibodies in the cholesterol-fed rabbit and to relate antibody titres to serum concentrations of von Willebrand factor (vWF), a marker of endothelial injury. Rabbits were fed with 0.25-1.0% cholesterol diet for 13 weeks. Plasma levels of anti Hsp-60, -65 and -70 IgG titres, were measured using in-house enzyme-linked immunosorbent assays (ELISAs) together with plasma vWF concentrations. Plasma titres of anti-Hsp-60, -65 and -70 antibodies were all significantly increased by weeks 5, 7 and 9 following commencement of the experimental diet compared with baseline (P < 0.05 for all). In non-cholesterol-fed rabbits, plasma levels of anti-Hsp titres were unchanged over this period. Increased plasma vWF concentrations were also found in the cholesterol-fed rabbits, reaching a maximum at approximately week 8, and falling thereafter. Furthermore, plasma vWF concentrations at 13 weeks correlated strongly with antibody titres to all three Hsps (r = 0.90, P = 0.002; r = 0.80, P = 0.017; r = 0.86, P = 0.006 for Hsp 60, -65 and -70 respectively) and titres were also strongly correlated with final plasma cholesterol concentrations in cholesterol-fed animals (r = 0.95, P = 0.002; r = 0.8, P = 0.001; r = 0.84, P = 0.01 respectively). In cholesterol-fed rabbits, antibody titres to Hsp-60, -65 and -70 appear to rise in association with a marker of endothelial injury, peaking at approximately the same time (8 weeks) after starting a high cholesterol diet.

Plasma Level of Mitochondrial Coupling Factor 6 Increases in Patients With Coronary Heart Disease

BACKGROUND

The aim of the present study was to investigate alterations in the plasma level of coupling factor 6 (CF6), a novel endogenous inhibitor of prostacyclin, in patients with coronary heart disease.

METHODS AND RESULTS

In total, 35 patients with coronary heart disease and 20 age-matched healthy subjects were examined. Plasma levels of CF6 and 6-keto-prostaglandin (PG)F(1a) (a stable metabolite of prostacyclin) were measured using radioimmunoassay. The plasma level of CF6 was significantly increased in patients (254.1+/-29.8 pg/ml vs 219.4 +/-36.7 pg/ml in controls, p<0.0001), whereas that of 6-keto-PGF(1a) was significantly decreased (23.4 +/-2.3 pg/ml vs 26.1+/-4.5 pg/ml in controls, p=0.001). Moreover, after percutaneous transluminal coronary angioplasty (PTCA) and stent therapy, the level of CF6 was further increased by 30% to 330.4+/-26.0 pg/ml, and that of 6-keto-PGF (1a) was decreased by 42% to 13.5+/-2.0 pg/ml, compared with baseline (all p<0.01). Univariate analysis showed a significant result that the plasma level of CF6 was inversely correlated with that of 6-keto-PGF(1a) in the patients. The plasma ratio of CF6 to 6-keto-PGF(1a) was 8.4 in the control group and that in patients with coronary heart disease was increased to 24.4 after the therapy from 10.9 before therapy.

CONCLUSIONS

The results suggest that an increased CF6 level may be responsible in part for the decreased prostacyclin level observed in patients with coronary heart disease, in particular after PTCA and stent therapy. As a potential risk factor for coronary heart disease, CF6 might have important clinical significance.

Activity of antioxidant enzymes in children from families at high risk of premature coronary heart disease

A positive family history of coronary heart disease (CHD) is one of the most predictive risk factors of CHD. Many children with increased risk of CHD because of their positive family history of CHD do not present other risk factors, such as altered serum lipid profile. Oxidative stress plays an important part in the pathogenesis of atherosclerosis. Serum antioxidants and intracellular enzymatic antioxidants composed mainly of glutathione peroxidase (GSH-Px), catalase (CAT), superoxide dismutase (SOD) and glutathione reductase counterbalance oxidative stress. Diminished activity of this system may lead to accelerated progression of atherosclerosis. The aim of this study was to assess the activity of CAT, GSH-Px, SOD and glutathione reductase in children with a family history of premature CHD who did not present any other major risk factors of CHD (diabetes, obesity, dyslipidaemia or hypertension). Twenty-two healthy children from high-risk families, selected according to the National Cholesterol Education Program definition, were enrolled in the study. The control group comprised 18 children without a family history of CHD. All the children were healthy and had been screened for hyperlipidaemia, diabetes, hypertension and obesity prior to the study. The erythrocyte activity of CAT, GSH-Px, SOD and glutathione reductase was assessed. Children at high risk of CHD had a statistically significant lower level of GSH-Px and CAT activity than the children in the control group. There were no statistically significant differences in the activity of SOD and glutathione reductase.

Endothelin-1 and vascular tone in subjects with atherogenic risk factors

Endothelin-1 (ET-1) is a potent vasoconstrictor that increases vascular tone in the resistance vessels of subjects with hypertension. It is unclear whether endogenous ET-1 affects resistance-vessel function equally in patients with other cardiovascular risk factors. Vasoconstriction to ET-1 is mediated principally via the endothelin-A (ETA) receptor on vascular smooth muscle cells. Accordingly, we used an ETA-specific antagonist, BQ-123, to test the hypothesis that endogenous ET-1 increases vascular resistance selectively in subjects with hypertension compared with other risk factors. BQ-123 was infused at 100 nmol/min for 80 minutes into the brachial artery of 10 subjects with hypertension (mean+/-SEM arterial pressure, 106+/-5 mm Hg), 12 subjects with hypercholesterolemia (mean+/-SEM total cholesterol, 7.1+/-0.2 mmol/L), 10 active smokers (mean+/-SEM, 42+/-11 pack-years), and 11 healthy, age-matched individuals. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. BQ-123 dilated resistance arterioles in hypertensive subjects, with FBF's increasing by 46+/-7% from baseline (P<0.001). BQ-123 increased FBF to a lesser extent in hypercholesterolemic (24+/-5%, P<0.001) and healthy (20+/-8%, P=0.007) individuals but did not affect FBF significantly in smokers (10+/-8%, P=0.185). The vasodilator response in hypertensive subjects, but not in hypercholesterolemic patients or smokers, was significantly greater than that in healthy individuals (P=0.012). Endogenous ET-1, acting via the ETA receptor, increases resistance-vessel tone in subjects with hypertension more than in subjects with hypercholesterolemia or in smokers. These results indicate that ET-1 contributes more to the pathophysiology of hypertension than of other risk factors in subjects without overt atherosclerosis.