Relationship of angiographically defined coronary artery disease to serum lipoproteins and apolipoproteins in young survivors of myocardial infarction

Placenta growth factor and sFlt-1 as biomarkers in ischemic heart disease and heart failure: a review

Coronary heart disease (CHD) and heart failure (HF) produce significant morbidity/mortality but identifying new biomarkers could help in the management of each. In this article, we summarize the molecular regulation and biomarker potential of PIGF and sFlt-1 in CHD and HF. PlGF is elevated during ischemia and some studies have shown PlGF, sFlt-1 or PlGF:sFlt-1 ratio, when used in combination with standard biomarkers, strengthens predictions of outcomes. sFlt-1 and PlGF are elevated in HF with sFlt-1 as a stronger predictor of outcomes. Although promising, we discuss additional study criteria needed to confirm the clinical usefulness of PlGF or sFlt-1 in the detection and management of CHD or HF.

Increased Risk of the APOB rs11279109 Polymorphism for CHD among the Kuwaiti Population

Background

Coronary heart disease (CHD) is among the leading causes of death in Kuwait. This case-control study investigated the genetic association of APOB rs11279109 with CHD in Kuwaitis.

Methods

The polymorphism was genotyped in 734 Kuwaiti samples by direct amplification. Statistical analysis with genetic modeling was used to assess its association with CHD.

Results

A statistically significant association (P < 0.001) between the rs11279109 DD genotype (OR: 2.43, CI: 1.34–4.41) with CHD was observed. A codominant genetic model revealed a 2.69 risk increase (CI: 1.57–4.61) for the DD genotype (P = 0.009) independent of age, sex, BMI, smoking, hypercholesterolemia, and ethnicity suggesting APOB rs11279109 as an indicator for the increased risk of CHD.

Conclusion

The DD genotype may explain molecular mechanisms that underline increased LDL oxidation leading to arthrosclerosis. The findings emphasize the need to identify genetic markers specific to the CHD patient ethnic group in order to improve prognosis and help in early diagnosis and prevention.

Case control feasibility study assessing the association between severity of coronary artery disease with Glutathione Peroxidase-1 (GPX-1) and GPX-1 polymorphism (Pro198Leu)

Background

Glutathione peroxidase-1 (GPX-1) activity was reported to be useful marker for monitoring cardiovascular disease. However, accurate assessment of coronary artery disease (CAD) using GPX-1 polymorphism is limited for South Asian population. Present study aim to assess GPX-1activity and GPX-1 polymorphismin patients with coronary artery disease (CAD) who were confirmed with coronary angiography findings and in apparently healthy subjects.

Methods

Case control study was carried out with 85 patients (58 males and 27 females) 40–60 years of age confirmed as having CAD on coronary angiography findings and 85 age and sex matched healthy volunteers as controls. Blood samples were analyzed for erythrocyte GPX-1 activity and GPX-1 polymorphism in both groups and the severity of CAD was assessed using coronary angiography scoring system based on vessel, stenosis and extent score.

Results

Coronary angiography scores indicated that erythrocyteGPX-1 cutoff value of 23.9 U/gHb showed a high sensitivity and negative predictive value in ruling out major vessel disease. The GPX-1 Pro198Leu (CT) polymorphism was higher in patients with CAD (25.3 %) when compared to controls (10.7 %). Pro198Leu (CT) genotype showed a 2.84 fold risk for CAD [odds ratio 2.84 (95 % CI 1.15–6.98), p = 0.019].

Conclusion

Coronary angiography findings indicated that individuals possessing Pro198Leu (CT) polymorphism were found to be associated with low erythrocyte GPX-1 activity and increased susceptibility for CAD.

Circulating malondialdehyde-modified LDL-related variables and coronary artery stenosis in asymptomatic patients with type 2 diabetes

AIMS

To elucidate the levels of malondialdehyde-modified LDL (MDA-LDL)-related variables for predicting coronary artery stenosis (CAS) by coronary CT angiography (CCTA) in asymptomatic patients with type 2 diabetes (T2DM).

METHODS

Enrolled were 36 Japanese patients with T2DM who underwent CCTA and in whom MDA-LDL levels were measured. Definition of CAS was luminal narrowing of ≥50%. Trends through tertiles of each MDA-LDL-related variable were analyzed with a general linear model. The ability of each MDA-LDL-related variable to predict CAS was compared to areas under the curve (AUCs) in receiver operating characteristic curve (ROC) analysis.

RESULTS

Seventeen patients had CAS. Each MDA-LDL-related variable was an independent predictor of CAS (P = 0.039 for MDALDL, P = 0.013 for MDA-LDL/LDL-C, P = 0.047 for MDA-LDL/HDL-C, and P = 0.013 for (MDA-LDL/LDL-C)/HDL-C). AUCs of MDA-LDL, MDA-LDL/LDL-C, MDA-LDL/HDL-C, and (MDA-LDL/LDL-C)/HDL-C were 0.675 (95% CI 0.496-0.854), 0.765 (0.602-0.927), 0.752 (0.592-0.913), and 0.799 (0.643-0.955), respectively, for predicting CAS. Trends throughout the tertiles showed significant associations between MDA-LDL/LDL-C, MDA-LDL/HDL-C, or (MDALDL/LDL-C)/HDL-C and CAS (P = 0.003 for MDA-LDL/LDL-C, P = 0.042 for MDA-LDL/HDL-C, and P = 0.001 for (MDA-LDL/LDL-C)/HDL-C).

CONCLUSIONS

Data suggest that measurements of MDA-LDL/LDL-C, MDA-LDL/HDLC, and (MDA-LDL/LDL-C)/HDL-C are useful for predicting CAS.

A new coronary artery disease grading system correlates with numerous routine parameters that were associated with atherosclerosis: a grading system for coronary artery disease severity

Background

Several scoring systems have tried to determine the severity of coronary artery disease (CAD) to investigate the connection between CAD severity and laboratory parameters.

Methods

In total, 189 male (mean age: 61.86±10.77 years) and 75 female CAD patients (mean age: 67.84±7.70 years) were recruited and underwent angiography, which determined stenosis grade, of 17 coronary segments: no points for each nonstenosed segment or only calcified segments, one point for each stenosis from <30% to <50%, two points for each stenosis from 50% to <70%, and three points for each stenosis >70%. The points were added and should represent the severity of patients’ CAD.

Results

The coronary score correlated positively with systolic blood pressure, creatinine, blood urea nitrogen, lipase, glucose, glycated hemoglobin, triglycerides, C-reactive protein, fibrinogen Clauss, and leukocytes, and correlated negatively with Cl⁻, iron, and high-density lipoprotein cholesterol. Stepwise multiple regression analysis with backward elimination revealed diabetes status, sex, and fibrinogen Clauss as significant predictors of coronary score.

Conclusion

The coronary score delivers a quite simple but very precise tool for the quantification of CAD severity. These results show plainly the connection between CAD severity and the lipid, glucose, coagulation, and immunologic status of CAD patients, and substantiate the importance of sufficient treatment in this group of patients – in particular, CAD patients suffering from type 2 diabetes mellitus. The coronary score would offer a suitable tool for the investigation of the connection between CAD and new biomarkers. Further studies are needed to investigate the correlation of the coronary score with outcome parameters (eg, death).

High-density lipoprotein subfractions and carotid plaque: the Northern Manhattan Study

OBJECTIVE

The objective of this cross-sectional analysis was to investigate the relation between two major high-density lipoprotein cholesterol (HDL-C) subfractions (HDL2-C and HDL3-C) and carotid plaque in a population based cohort.

METHODS

We evaluated 988 stroke-free participants (mean age 66 ± 8 years; 40% men; 66% Hispanic and 34% Non-Hispanic) with available data on HDL subfractions using precipitation method and carotid plaque area and thickness assessed by a high-resolution 2D ultrasound. The associations between HDL-C subfractions and plaque measurements were analyzed by quantile regression.

RESULTS

Plaque was present in 56% of the study population. Among those with plaque, the mean ± SD plaque area was 19.40 ± 20.46 mm² and thickness 2.30 ± 4.45 mm. The mean ± SD total HDL-C was 46 ± 14 mg/dl, HDL2-C 14 ± 8 mg/dl, and HDL3-C 32 ± 8 mg/dl. After adjusting for demographics and vascular risk factors, there was an inverse association between HDL3-C and plaque area (per mg/dl: beta = -0.26 at the 75th percentile, p = 0.001 and beta = -0.32 at the 90th percentile, p = 0.02). A positive association was observed between HDL2-C and plaque thickness (per mg/dl; beta = 0.02 at the 90% percentile, p = 0.003). HDL-C was associated with plaque area (per mg/dl: beta = -0.18 at the 90th percentile, p = 0.01), but only among Hispanics.

CONCLUSION

In our cohort we observed an inverse association between HDL3-C and plaque area and a positive association between HDL2-C and plaque thickness. HDL-C subfractions may have different contributions to the risk of vascular disease. More studies are needed to fully elucidate HDL-C anti-atherosclerotic functions in order to improve HDL-based treatments in prevention of vascular disease and stroke.

Statin use for nonrheumatic calcific aortic valve stenosis: a review with meta-analysis

AIMS

To synthesize by meta-analysis the findings of recent experimental studies focusing on possible therapeutic effectiveness of statins for nonrheumatic calcific aortic stenosis.

METHODS

Observational studies and randomized controlled trials (RCTs) were selected from the Pubmed database to evaluate the hemodynamic progression of aortic stenosis in statin-treated patients compared with controls (i.e. patients with aortic stenosis taking placebo or no treatment). The endpoints were the annualized changes in one or more of the following ultrasonographic measurements: peak aortic valve jet velocity, peak aortic valve pressure gradient, mean aortic valve pressure gradient aortic valve area (AVA). For estimating the overall effect of statin therapy on each of the above-mentioned continuous variables across the considered studies, we used the weighted mean difference (WMD) as effect size measure. In addition, we calculated the odds of aortic valve replacement surgery and cardiovascular death in both statin-treated patients and controls for subsequently estimating the appropriate odds ratios.

RESULTS

Nine studies were selected. A lower annualized increase in peak aortic valve jet velocity was found in statin-treated patients compared with controls (overall WMD: -0.09 m/s per year, 95% CI -0.16, -0.01 P = 0.018). Similarly, a smaller annualized increase in peak aortic valve pressure gradient was found in the statin group (overall WMD: -2.04 mmHg/year 95% CI: -3.56, -0.52, P = 0.0085). However, the overall effects in statin-treated patients on both annualized increases in mean aortic valve pressure gradient and decreases in AVA were not significantly different from those found in controls. Moreover, there was no significant difference in cardiovascular outcomes in the statin groups compared with placebo groups in each of the three analyzed RCTs and overall.

CONCLUSION

Significant benefit of statin therapy in retarding hemodynamic deterioration was identified by favorable effects concerning annualized changes in peak aortic valve jet velocity and peak aortic valve pressure gradient; on the contrary, in statin-treated patients with aortic stenosis, no significant improvement was found for annualized changes in mean aortic valve pressure gradient and AVA and clinical outcomes.

Atherogenic low density lipoprotein phenotype in long-term survivors of childhood acute lymphoblastic leukemia

Survivors of childhood acute lymphoblastic leukemia (ALL) have an increased risk of cardiovascular disease. Small density lipoproteins are atherogenic but have not been studied in this population. We conducted a cross-sectional analysis of 110 ALL survivors (mean age, 24.3 years) to determine prevalence of small dense LDL (pattern B) phenotype in ALL survivors and identify associated factors. Lipid subfractions were measured using Vertical Auto Profile-II. Participants with greater than 50% of LDL-cholesterol (LDL-c) in small dense LDL fractions (LDL(3+4)) were classified as LDL pattern B. Visceral and subcutaneous adipose tissue (VAT, SAT) volumes were also measured by computed tomography. While the mean LDL-c level of ALL survivors was 108.7 ± 26.8 mg/dl, 36% (40/110) of survivors had atherogenic LDL pattern B. This pattern was more common in males (26/47; 55%) than in females (14/63; 22%, P = 0.001) and more common in survivors treated with cranial radiotherapy (15/33; 45%) than in those who were treated with chemotherapy alone (25/77; 33%; P = 0.04, adjusted for age, gender, history of hypertension, and smoking history). VAT was associated with atherogenic lipids: LDL pattern B and LDL(3+4) levels. This association was independent of other measures of body fat. We conclude that a substantial proportion of ALL survivors had an atherogenic LDL phenotype despite normal mean LDL-c levels. An atherogenic LDL phenotype may contribute to the increase in cardiovascular mortality and morbidity in this population.

A higher burden of small low-density lipoprotein particles is associated with profound changes in the free androgen index in male adolescents

From a young age, males are at higher cardiovascular risk than females. Dyslipidemia, including a higher burden related to small low-density lipoproteins (LDL), plays an important role in precipitating atherosclerosis in both males and females. We investigated sex differences in atherogenic lipoprotein burden and the independent predictors of LDL particle size in children and adolescents. We measured the concentrations of total testosterone, sex hormone-binding globulin, estradiol, total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, and LDL particle size in 135 children and adolescents (67 boys, 68 girls). The free androgen index was significantly and negatively correlated with LDL particle size (r = -0.273, P = 0.026) in boys, but estrogen and LDL particle size were not related. In a stepwise multiple regression analysis adjusted for body mass index, age, and homeostasis model assessment for insulin resistance, free androgen index was still an independent predictor of LDL particle size in boys (R(2) = 0.075, P = 0.026). The prominent decrease in LDL particle size along with increased testosterone concentrations in males might explain why they are more likely to display atherogenic dyslipidemia from adolescence.

Association of epicardial adipose tissue with coronary atherosclerosis is region-specific and independent of conventional risk factors and intra-abdominal adiposity

OBJECTIVE

To elucidate which measurement of epicardial adipose tissue (EAT) best reflects its atherogenic risk, we examined the associations between different EAT measurements and various atherosclerotic parameters of the entire coronary tree and individual coronary arteries.

METHODS

This study included 224 consecutive patients underwent multidetector computed tomography before diagnostic coronary angiography. Regional thickness, cross-sectional areas, and total volume of EAT were measured. Four atherosclerotic parameters, including severity score, extent score, calcium volume score, and number of coronary arteries with ≥50% luminal stenosis, of the entire coronary tree and individual coronary arteries were assessed.

RESULTS

Both total EAT volume and thickness of EAT in the left atrioventricular groove were unanimously associated with the presence of coronary atherosclerosis dichotomously defined by the 4 scoring systems. However, only EAT thickness in the left atrioventricular groove, but not total EAT volume, was significantly associated with all 4 parameters of coronary atherosclerosis in a dose-dependent manner, even after adjustments for conventional risk factors, body-mass index, waist circumference, C-reactive protein, and intra-abdominal visceral fat area. Using the receiver-operating-characteristic analysis, 12.2mm was the optimal cutoff point for left atrioventricular groove thickness to predict the presence of significant coronary stenosis (≥50% diameter stenosis). Among the three coronary arteries, left atrioventricular groove thickness was most strongly correlated with ≥50% diameter stenosis in the embedded left circumflex artery by multivariate regression model.

CONCLUSIONS

Thickness of EAT in the left atrioventricular groove provides a more accurate assessment of its atherogenic risk and is therefore a better coronary risk factor than total EAT volume.

Prospective studies on the relationship between high-density lipoprotein cholesterol and cardiovascular risk: a systematic review

Epidemiological studies have extensively evaluated the association between high-density lipoprotein cholesterol (HDL-C) and cardiovascular disease (CVD) risk. The objective of this systematic review was to enumerate the number of original prospective studies that showed a significant association between HDL-C and CVD risk and provided evidence of the consistency of this association across other lipid risk factors. A systematic MEDLINE literature search identified 53 prospective cohort and five nested case-control studies that provided multivariate assessments of the association between HDL-C and CVD risk. Among these 58 prospective studies, 31 studies found a significant inverse association between HDL-C and CVD risk for all CVD outcomes and subpopulations studied, whereas 17 studies found a significant association for some CVD outcomes and/or subpopulations assessed. The ratio of studies that found a significant association out of the total studies identified was similar across all CVD outcomes, although there was less evidence for stroke and atherosclerotic outcomes. Only seven studies tested for the consistency of this association across other lipid risk factors, of which six studies suggested that the association was consistent across other lipid levels. In conclusion, the association between HDL-C and CVD risk is significant and strong, although further evidence may be needed to establish whether this association is consistent across other lipid risk factors. Furthermore, uncertainties remain regarding the mechanism in which HDL-C exerts its effects, suggesting a need for further research focused on new methods for reliable measurement.

Lipids, lipid modifying agents and cardiovascular risk: a review of the evidence

It is well-established that serum total-cholesterol, LDL-cholesterol, low HDL-cholesterol and calculated indices such as total cholesterol:HDL-cholesterol ratio or less commonly used indices such as non-HDL cholesterol are strongly predictive of cardiovascular events. Serum triglycerides, by contrast, are only modestly associated with coronary heart disease (CHD) in multivariate analysis and incorporation of triglycerides into prediction algorithms is therefore unlikely to improve their prediction capability. Meta-analysis of studies including > 90,000 subjects has provided robust evidence that statins reduce important clinical end-points. These included a 12% fall in all-cause mortality, 19% fall in CHD mortality and 23% fall in CHD mortality or myocardial infarction. Furthermore there are high quality data showing additional benefit of intensive statin therapy over standard statin therapy for secondary prevention of cardiovascular disease. However, meta-analysis of 10 fibrate trials has shown inconsistent evidence of vascular benefit and non-cardiovascular mortality has been slightly but consistently elevated in most fibrate trials and in meta-analysis. The general use of fibrates for cardiovascular risk reduction can therefore not be supported at present. Other second line agents such as bile acid sequestrants, nicotinic acid and omega-3 fatty acid supplements have been evaluated in a few randomized controlled studies in which cardiovascular benefit has been found but clearly further data are required to properly establish their use in clinical practice. Ongoing studies such as ACCORD, IMPROVE-IT, ASCEND, ORIGIN and HPS2-THRIVE should assist in answering outstanding questions over the next 5 years.

Determining the relationship between metabolic syndrome score and angiographic severity of coronary artery disease

BACKGROUND

Cardiovascular disease is leading cause of mortality and morbidity in developed and developing countries. Metabolic syndrome (MS) is a risk factor for coronary artery disease (CAD). The effect of MS on angiographic severity of CAD is not well defined. The aim of this study was to examine the effect of MS on angiographic severity of CAD by using Gensini score.

METHODS

The total number of 1003 patients who underwent elective coronary angiography in catheter laboratory were included in the study. MS score based on National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria which ranged between zero and five were calculated for each subject. Gensini scores were determined by examining coronary angiograms of the patients.

RESULTS

The study population consisted of 634 (63%) male, and 369 (37%) female subjects. The mean age was 59 +/- 11. MS based on NCEP ATP III was present in 246 (25%) patients. CAD was present in 691 patients (69%). The median of Gensini score was five (0-192) in the total sample, 18 (1-192) in the patients with CAD and 25 (0-192) in the patients with MS. A positive correlation was found between MS score and Gensini score (r = 0.402, p < 0.001).

CONCLUSIONS

In this study, it was determined that as the severity of MS increases, the angiographic severity of CAD increases as well. Besides, the most important factor on Gensini score was diabetes mellitus in male and hypertension in female subjects.

Renal dysfunction is the most important predictor of the extent and severity of coronary artery disease in patients with diabetes mellitus

OBJECTIVES

Diabetic patients tend to have more extensive and diffuse coronary artery disease (CAD) that may contribute to the less favorable outcomes in them. The aim of this study was to elucidate the predictors of the angiographic severity and extent of CAD in patients with diabetes.

METHODS

A total of 203 diabetic patients (116 men; mean age, 61.9+/-10.8) who were referred for a first coronary angiogram were included. The extent and severity of CAD was assessed in several ways. The first was a simple classification in one-vessel, two-vessel, and three-vessel disease scoring system. The total numbers of segments with > or = 20 and > or = 50% stenosis were calculated as CASS 20 and CASS 50 scores, respectively. Hamsten and Gensini scores were also calculated.

RESULTS

Of the 203 patients included in the study, 175 (86.2%) had CAD. Multivariate ordinal logistic regression analysis showed that age (Wald 5.741, P=0.017), glomerular filtration rate (Wald 5.032, P=0.025), previous myocardial infarction (Wald 10.955, P=0.001), and family history of CAD (Wald 7.236, P=0.007) were independent predictors of the severity of CAD, as assessed by the clinical zero-vessel to three-vessel disease scoring system. On stepwise multiple linear regression analysis, glomerular filtration rate was an independent predictor of the CASS 20 (r=-0.221, P=0.004), CASS 50 (r=-0.239, P=0.005), Gensini (r=-0.328, P<0.001), and Hamsten (r=-0.320, P<0.001) scores. Previous myocardial infarction was an independent predictor of the CASS 50 (r=0.355, P<0.001), Gensini (r=0.350, P<0.001), and Hamsten (0.256, P<0.001) scores. Age and sex were independent predictors for the CASS 50 (r=0.174, P=0.039; r=0.172, P=0.016, respectively) and Hamsten (r=0.212, P=0.011; r=0.244, P=0.001, respectively) scores.

CONCLUSION

Renal function is one of the most important factors associated with the extent and severity of coronary atherosclerosis, whereas classical coronary risk factors and the degree of metabolic control were not associated with the severity of coronary atherosclerosis in diabetic patients.

Dietary phytosterols reduce probucol-induced atherogenesis in apo E-KO mice

We have previously shown strong pro-atherogenic effects of probucol in apolipoprotein E-knockout (apo E-KO) mice. The aims of the present study were to investigate whether (a) dietary phytosterols reduce probucol-induced atherogenesis and (b) beneficial interactions exist between these agents. Male apo E-KO mice fed with an atherogenic diet supplemented with phytosterols or probucol or their combination for 14 weeks. Single therapy with either phytosterols or probucol resulted in a 25% reduction in plasma total cholesterol (TC) concentrations as compared to the control group. The effects of the combination therapy were more profound (60% reduction). While phytosterols reduced atherogenesis by 60%, probucol caused an increase of 150% in atherogenesis. Addition of phytosterols to probucol substantially reduced pro-atherogenic effects of probucol. This was associated with improved high density lipoprotein (HDL) concentrations. The ratio of TC to HDL cholesterol was markedly reduced in the combination therapy group as compared to the probucol-treated group. A strong positive association between the ratio of TC to HDL cholesterol and the extent of atherosclerotic lesions was observed. The coronary arteries of the probucol-treated group showed various stages of atherogenesis from infiltration of monocytes into intima to complete occlusion of the vessel by atheromatous lesions. Such pathological findings were not observed in the combination therapy group. Approximately 40% of the mice in the probucol-treated group and 10% of the animals in the combination therapy group developed skin lesions. Further studies warrant the investigation of the underlying mechanisms of the observed beneficial interactions between dietary phytosterols and probucol.

Plasma matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-2, and CD40 ligand levels in patients with stable coronary artery disease

Endogenous matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), are important mediators of extracellular matrix remodeling, which is integral to plaque progression in coronary artery disease. In addition, high levels of the soluble fragment of CD40 ligand (sCD40L) have previously been associated with adverse cardiovascular outcomes. We hypothesized that circulating levels of MMP-9, TIMP-1, TIMP-2, and sCD40L were abnormal in patients who had stable coronary artery disease, and these levels were compared with those in matched controls. We also hypothesized correlations of MMPs, TIMPs, and sCD40L to each other and to high-sensitivity C-reactive protein (a proinflammatory marker), white blood cell count, severity of coronary artery disease (based on angiographic measurements of atherosclerotic burden), and coronary collateralization. We studied 204 adult patients who attended our unit for outpatient diagnostic cardiac catheterization for the investigation of suspected coronary artery disease. Coronary angiograms were scored for atheroma burden and stenosis by 2 independent observers. Circulating levels of MMP-9, TIMP-1, TIMP-2, and sCD40L were measured by enzyme-linked immunosorbent assay. Plasma levels of MMP-9 (p = 0.0099), TIMP-2 (p = 0.0019), and sCD40L (p <0.001), but not TIMP-1 (p = 0.463) were high in patients compared with healthy controls. In patients who had coronary artery disease, MMP-9 and high-sensitivity C-reactive protein levels were significantly higher in women than in men. Only MMP-9 correlated modestly with total white blood cell count (Spearman's correlation, r = 0.274, p = 0.002). Logistic regression of cardiovascular risk factors showed that only white blood cell count was independently associated with MMP-9 (p = 0.02). After standardizing for atheroma and stenosis scores, there were no statistically significant differences in our research indexes in patients who had angiographic collaterals compared with those who did not. In conclusion, stable coronary artery disease is associated with abnormal circulating levels of MMP-9, TIMP-2, and sCD40L, which do not appear to related to each other or to severity of coronary artery disease or collateralization. The gender difference in high-sensitivity C-reactive protein and MMP-9 levels may provide insight into the pathophysiology of coronary artery disease in men and women, and further studies are warranted to explore this potential link.

Hemodynamic, hemostatic, and endothelial reactions to psychological and physical stress in coronary artery disease patients

Episodes of psychological and physical stress may elicit thrombotic cardiac events, such as myocardial infarction. These events are triggered when there are concurrent hemodynamic, hemostatic, and endothelial abnormalities. Hemodynamic, hemostatic, and endothelial reactions of 72 (15 women, 57 men) coronary artery disease patients to psychological and physical stress were examined. Blood pressure, electrocardiography, and impedance cardiography were recorded during rest, mental arithmetic, and exercise. Blood was collected, via catheter, at rest and after each task. Mental arithmetic elicited increases in blood pressure, heart rate, cardiac output, and cardiac contractility, but no consistent changes in hemostatic and endothelial markers. In contrast, exercise, in addition to increasing blood pressure, heart rate, cardiac output, cardiac contractility, and lowering peripheral resistance, elicited increases in plasma viscosity, hematocrit, platelets, and tissue plasminogen activator together with a decrease in plasminogen activator inhibitor. This pattern of hemodynamic, hemostatic, and endothelial reactions suggests that acute psychological and physical stress influence the thrombotic system differently in these high risk patients. Future research is needed to investigate how these stress responses are prospectively related to acute cardiac events.

Dietary cholesterol does not increase biomarkers for chronic disease in a pediatric population from northern Mexico

BACKGROUND

An increased incidence of coronary artery disease (CAD) is prevalent in northern Mexico. Effects of specific dietary components on risk factors for CAD have not been evaluated in children.

OBJECTIVE

The purpose was to evaluate the effects of dietary cholesterol provided by whole eggs on the lipoprotein profile, LDL size, and phenotype in children from this region.

DESIGN

Children (29 girls and 25 boys aged 8-12 y) were randomly assigned to either 2 eggs/d (EGG period; 518 additional mg cholesterol) or the equivalent amount of egg whites (SUB period; 0 additional mg cholesterol) for 30 d. After a 3-wk washout period, the children were assigned to the alternate treatment.

RESULTS

Subjects were classified as hyporesponders (no increase or </=0.05 mmol/L increase in plasma cholesterol for 100 mg additional cholesterol) or hyperresponders (>/=0.06 mmol/L increase). During the EGG period, the hyperresponders (n = 18) had an elevation in both LDL cholesterol (from 1.54 +/- 0.38 to 1.93 +/- 0.36 mmol/L) and HDL cholesterol (from 1.23 +/- 0.26 to 1.35 +/- 0.29 mmol/L) with no changes in LDL:HDL. In contrast, hyporesponders (n = 36) had no significant alterations in plasma LDL or HDL cholesterol. All subjects had an increase in LDL peak diameter during the EGG period (P < 0.01) and a decrease (P < 0.01) in the smaller LDL subfractions. In addition, 5 of the children having LDL phenotype B (15%) shifted from this high-risk pattern to pattern A after the EGG treatment.

CONCLUSIONS

Intake of 2 eggs/d results in the maintenance of LDL:HDL and in the generation of a less atherogenic LDL in this population of Mexican children.

Comparison of the extent and severity of coronary artery disease in patients with acute myocardial infarction with and without microalbuminuria

The extent and severity of coronary atherosclerosis were compared between 43 microalbuminuric and 87 normoalbuminuric nondiabetic patients with acute myocardial infarction. Patients with microalbuminuria had significantly greater scores of the severity (Gensini score) and extent (Hamsten score) of coronary artery disease (p <0.001).

High intake of cholesterol results in less atherogenic low-density lipoprotein particles in men and women independent of response classification

The influence of a high-cholesterol diet on the atherogenicity of the low-density lipoprotein (LDL) particle was examined by measuring LDL peak diameter and composition, LDL susceptibility to oxidation, and the distribution of cholesterol between LDL subclasses. The crossover intervention randomly assigned 27 premenopausal women and 25 men (18 to 50 years) to an egg (640 mg/d additional dietary cholesterol) or placebo (0 mg/d additional dietary cholesterol) diet for 30 days, followed by a 3-week washout period. Subjects were classified as either hyperresponders (>2.5 mg/dL increase in plasma cholesterol for each 100 mg additional dietary cholesterol consumed) or hyporesponders to dietary cholesterol. Sex was found to have a significant effect on 3 of the parameters examined. LDL peak diameter was significantly larger (P <.005) in females (26.78 +/- 0.59 nm, n = 27) as compared with males (26.52 +/- 0.49 nm, n = 25), regardless of response to dietary cholesterol. The LDL particles of the male participants also had a higher number of triglyceride (TG) and cholesteryl ester (CE) molecules (P <.01); however, cholesterol ester transfer protein (CETP) activity was higher in females (P <.05). Response classification also revealed significant differences in the determination of LDL subclasses. Independent of sex, the LDL-1 particle (P <.05), which is considered to be less atherogenic, was predominant in hyperresponders and this finding was associated with increased cholesterol intake (interactive effect, P <.001). In addition, CETP and lecithin: cholesterol acyltransferase (LCAT) activities were higher in hyperresponders during the egg period (interactive effect, P <.05). Sex, response to cholesterol intake, and diet were not found to affect the susceptibility of LDL to oxidation (P > 0.5). Because LDL peak diameter was not decreased and the larger LDL-1 subclass was greater in hyperresponders following egg intake, these data indicate that the consumption of a high-cholesterol diet does not negatively influence the atherogenicity of the LDL particle.

Apolipoprotein B and apolipoprotein A-I: risk indicators of coronary heart disease and targets for lipid-modifying therapy

Although LDL cholesterol (LDL-C) is associated with an increased risk of coronary heart disease, other lipoproteins and their constituents, apolipoproteins, may play an important role in atherosclerosis. Elevated levels of apolipoprotein (apo) B, a constituent of atherogenic lipoproteins, and reduced levels of apo A-I, a component of anti-atherogenic HDL, are associated with increased cardiac events. Apo B, apo A-I and the apo B/apo A-I ratio have been reported as better predictors of cardiovascular events than LDL-C and they even retain their predictive power in patients receiving lipid-modifying therapy. Measurement of these apolipoproteins could improve cardiovascular risk prediction.

Angiogenesis, thrombogenesis, endothelial dysfunction and angiographic severity of coronary artery disease

BACKGROUND

Thrombogenesis, angiogenesis, and endothelial damage/dysfunction are components in the pathogenesis of atherosclerosis.

OBJECTIVE

To investigate the relation of these variables to atherosclerotic disease severity and the possible interrelations between the three.

METHODS

111 patients attending for coronary angiography were studied (85 male, 26 female; mean (SD) age, 61.6 (10.0) years). Plasma concentrations of von Willebrand factor (vWf, a marker of endothelial damage/dysfunction), vascular endothelial growth factor (VEGF, associated with angiogenesis), soluble VEGF receptor Flt-1 (sFlt-1), and tissue factor (TF, a key component of coagulation) were measured by an enzyme linked immunosorbent assay. Following angiography, disease severity was assessed by the number of coronary vessels diseased (> 50% stenosis) and by a coronary atheroma score.

RESULTS

All indices were raised in the patients compared with 34 healthy controls except sFlt-1, which was lower in the patients. No significant correlations were found between the coronary atheroma score and values of vWf (Spearman correlations: r = 0.21, p = 0.83), VEGF (r = 0.11, p = 0.27), or TF (r = -0.04, p = 0.68). However, there was an inverse correlation between plasma sFlt-1 and coronary atheroma score (r = -0.19, p = 0.049). The number of vessels diseased had no relation to any marker. Correlations were found between TF and VEGF (r = 0.25, p = 0.008) and between TF and sFlt-1 (r = 0.42, p < 0.001) in the patients.

CONCLUSIONS

Despite evidence of abnormal angiogenesis (VEGF and sFlt-1), thrombogenesis (TF), and endothelial damage/dysfunction (vWf) in the patients with coronary artery disease, there was no correlation between VEGF, sFlt-1, vWf, or TF and angiographically defined disease severity.

Measurement of cholesterol of major serum lipoprotein classes by anion-exchange HPLC with perchlorate ion-containing eluent

We have developed a high-performance liquid chromatography (HPLC) method for measurement of cholesterol in the major classes of serum lipoproteins, i.e., HDL, LDL, IDL, VLDL, and chylomicrons. Lipoproteins in serum were separated on a column containing diethylaminoethyl-ligand nonporous polymer-based gel by elution with a step gradient of sodium perchlorate concentration, and detected by post-column reaction with a reagent containing cholesterol esterase and cholesterol oxidase. The within-day assay and between-day assay coefficients of variation for cholesterol concentration in lipoproteins were in the ranges of 0.9-6.4% and 1.1-11.9%, respectively. The correlation coefficients between the values of HDL, LDL, IDL, VLDL, and chylomicron cholesterol measured by the HPLC method and those estimated by an ultracentrifugation method were 0.892, 0.921, 0.840, 0.930, and 0.873, respectively. Values of remnant-like particle cholesterol measured by an immunoseparation technique (Japan Immunoresearch Laboratories, Japan) were significantly correlated with VLDL and chylomicron cholesterol values measured by the HPLC method (r = 0.883 and r = 0.729, respectively). This rapid and accurate HPLC method was successfully applied to the analysis of plasma lipoproteins of patients with hyperlipidemia.

Association of cholesterol levels, hydroxymethylglutaryl coenzyme-A reductase inhibitor treatment, and progression of aortic stenosis in the community

OBJECTIVES

This study was designed to analyze the association among cholesterol levels, lipid-lowering treatment, and progression of aortic stenosis (AS) in the community.

BACKGROUND

Aortic stenosis is a progressive disease for which there is no known medical treatment to prevent or slow progression. Despite plausible pathologic mechanisms linking hypercholesterolemia to AS progression, clinical studies have been inconsistent and affected by referral bias, and the role of lipid-lowering therapy is uncertain.

METHODS

We determined the association between blood cholesterol levels and progression of native AS (assessed by Doppler echocardiography at baseline and at least six months later; mean interval, 3.7 +/- 2.3 years) in a community-based study of 156 patients (age 77 +/- 12 years; 90 men). Thirty-eight patients received statin treatment during follow-up.

RESULTS

In untreated subjects, mean gradient increased from 22 +/- 12 mm Hg to 39 +/- 19 mm Hg, and aortic valve area (AVA) decreased from 1.20 +/- 0.35 cm(2) to 0.91 +/- 0.33 cm(2) (both p < 0.001). The annualized change in AVA was -0.09 +/- 0.17 cm(2)/year (-7% +/- 13%/year). Neither total cholesterol (r = -0.01, p = 0.92) nor low-density lipoprotein cholesterol (r = 0.01; p = 0.88) showed a significant correlation to AS progression. Nevertheless, progression of AS was slower in patients receiving statins compared with untreated patients (decrease in AVA -3 +/- 10% vs. -7 +/- 13% per year, respectively; p = 0.04), even when adjusted for age, gender, cholesterol, and baseline valve area (p = 0.04). The association of statin treatment with slower progression was confirmed when analysis was restricted to patients coming for a systematic follow-up (p=0.02). The odds ratio of AS progression with statin treatment was 0.46 (95% confidence interval, 0.21 to 0.96).

CONCLUSIONS

In the community, progression of AS shows no trend of association with cholesterol levels. Statin treatment, however, is associated with slower progression, suggesting that the effects of statin treatment on progression of AS should be pursued with appropriate clinical trials.

A single daily dose of soybean phytosterols in ground beef decreases serum total cholesterol and LDL cholesterol in young, mildly hypercholesterolemic men

BACKGROUND

Consumption of phytosterol-supplemented margarine lowers total plasma cholesterol (TC) and LDL-cholesterol concentrations in older middle-aged hypercholesterolemic individuals. The effects of incorporating phytosterols into lower-fat foods on the plasma lipids of young men at increased risk of developing cardiovascular disease have not been studied.

OBJECTIVE

We tested the hypothesis that a single daily dose of soybean phytosterols added to ground beef will lower plasma TC and LDL-cholesterol concentrations in mildly hypercholesterolemic young men.

DESIGN

In a triple-blind, 4-wk study, 34 male college students with elevated plasma TC (5.85 +/- 0.70 mmol/L), LDL cholesterol (4.02 +/- 0.60 mmol/L), and TC:HDL cholesterol (5.5 +/- 1.2) were randomly assigned to the control (ground beef alone) or treatment (ground beef with 2.7 g of phytosterols) group. The phytosterol mixture was two-thirds esterified and one-third nonesterified and consisted of beta-sitosterol (48%), campesterol (27%), and stigmasterol (21%).

RESULTS

Consumption of phytosterol-supplemented ground beef lowered plasma TC and LDL-cholesterol concentrations and TC:HDL cholesterol from baseline by 9.3%, 14.6%, and 9.1%, respectively (P < 0.001). The LDL particle size did not change, suggesting that the decrease was primarily of particle number. The decreases were similar in subjects with (n = 8) and without (n = 9) a family history of premature cardiovascular disease. No significant changes were found in the control group.

CONCLUSION

Phytosterol-supplemented ground beef effectively lowers plasma TC and LDL cholesterol and has the potential to become a functional food to help reduce the risk of cardiovascular disease.

Apolipoprotein E4 polymorphism as risk factor for coronary heart disease among Indian subjects

Apolipoprotein E genotypes and lipid and lipoprotein levels were determined in hypercholesterolemic and angiographically vertified CHD subjects and compared against 90 normolipidemic controls. The ε4 allele was significantly prevalent in the hypercholesterolemic and CHD subjects. Significant increase in total cholesterol levels in apo ε4 containing subjects were observed in the hypercholesterolemic and CHD group. The study suggests that the ε4 allele by influencing the lipid levels could act as a risk factor for CHD.

Determinants of the severity and extent of coronary artery disease in patients with type-2 diabetes and in nondiabetic subjects

BACKGROUND

Factors predicting the anatomic distribution and the severity and extent of coronary atherosclerosis in patients with clinically manifest coronary artery disease (CAD) for type-2 diabetic patients could be different than those for nondiabetic patients.

OBJECTIVE

To study the determinants of severity and extent of CAD in consecutive patients with type 2 diabetes mellitus, compared with those for matched nondiabetic patients, undergoing clinically indicated coronary angiography.

METHODS

Coronary angiograms of 48 men and seven women with type-2 diabetes and an equal number of nondiabetic subjects were analyzed quantitatively. Scores reflecting severity and extent of CAD were compared with potential risk factors using univariate correlation analyses and multivariate regression models.

RESULTS

For the diabetics, a global coronary atheroma burden index was independently and directly related to age (P = 0.022) and to level of intermediate-density lipoprotein cholesterol (P = 0.055), and inversely to level of particles of a subtype of high-density lipoprotein (P = 0.022). Several angiographic indexes were related to the duration of diabetes and control of glycemia. For the nondiabetic group, global atheroma burden was independently related to age (P = 0.028), a history of hypertension (P = 0.028), and concentration of low-density lipoprotein (P = 0.013), and inversely to level of apolipoprotein A-I (P = 0.008). The duration of coronary disease and a history of smoking were also predictive of severe coronary atherosclerosis among nondiabetic patients.

CONCLUSIONS

Classical risk factors are strong predictors of the severity and extent of coronary atherosclerosis in nondiabetic patients, but the most important determinants for type-2 diabetic patients are levels of triglyceride-rich lipoproteins and apolipoprotein A-I-containing particles of high-density lipoprotein, and factors directly related to diabetes.

Evidence that triglycerides are an independent coronary heart disease risk factor

In the past, the relation between hypertriglyceridemia and coronary heart disease (CHD) has been uncertain. However, a recent multivariate analysis of 8-year follow-up data from the large-scale Prospective Cardiovascular Münster study found hypertriglyceridemia to be an independent risk factor for major coronary events after controlling for low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol. Hypertriglyceridemia combined with elevated LDL cholesterol and high LDL:HDL cholesterol ratio (>5) increased the CHD event risk by approximately sixfold. Similarly, a large meta-analysis of 17 prospective trials reported hypertriglyceridemia to be an independent risk factor for cardiovascular disease. In this study, an 88 mg/dl (1.0 mmol/L) increase in plasma triglyceride levels significantly increased the relative risk of cardiovascular disease by approximately 30% in men and 75% in women; the corresponding rates were somewhat lower (14% and 37%) but still statistically significant after adjustment for HDL cholesterol level. These data and observations from patients in the Helsinki Heart Study and the Stockholm Ischemic Heart study, that the greatest coronary benefit during lipid-lowering drug therapy occurred among hypertriglyceridemic patients, argue strongly for an independent role for hypertriglyceridemia in CHD risk. In the recent Veterans Affairs Cooperative Studies Program High-Density Lipoprotein Cholesterol Intervention Trial, the use of gemfibrozil to raise HDL cholesterol levels and lower levels of triglycerides without lowering LDL cholesterol levels reduced coronary events in men with established CHD, whereas preliminary results from the Bezafibrate Infarction Prevention Trial indicate a reduction in coronary end points in patients with elevated baseline triglyceride levels. To achieve the greatest possible reduction in CHD risk, antihyperlipidemic treatment strategies should also be aimed at reducing elevated triglycerides.

Focus on HDL: a new treatment paradigm for athero-thrombotic vascular disease

Atherosclerotic vascular disease is the leading cause of mortality and morbidity in much of the Western world. Although advances in lifestyle and risk factor modification, pharmacotherapy, endovascular interventions and surgery have considerably improved clinical outcome, 40 - 50% of adverse cardiovascular events continue to occur despite current strategies. A number of new targets for therapeutic exploitation are currently being investigated that include, among others, apolipoprotein A-I, the major structural component of high density lipoprotein (HDL) particle. The strong negative relationship between HDL-cholesterol levels and coronary heart disease in epidemiological studies, as well as data from experimental models suggest that HDL-based therapies could be an important new paradigm for prevention, treatment and reversal of atherosclerotic vascular disease.

Preventing, stopping, or reversing coronary artery disease--triglyceride-rich lipoproteins and associated lipoprotein and metabolic abnormalities: the need for recognition and treatment

A substantial number of treated patients with or at high risk for coronary artery disease continue to have fatal and nonfatal coronary artery events in spite of significant reduction of elevated levels of low-density lipoprotein cholesterol. Other lipoprotein abnormalities besides an elevated level of low-density lipoprotein cholesterol contribute to risk of coronary artery disease and coronary artery events, and the predominant abnormalities that appear to explain much of this continued risk are an elevated serum triglyceride level and a low level of high-density lipoprotein cholesterol. Most patients with coronary artery disease have a mixed dyslipidemia with hypertriglyceridemia, which is associated and metabolically intertwined with other atherogenic risk factors, including the presence of triglyceride-rich lipoprotein remnants, low levels of high-density lipoprotein cholesterol, small, dense, low-density lipoprotein particles, postprandial hyperlipidemia, and a prothrombotic state. Aggressive treatment of these patients needs to focus on these other lipoprotein abnormalities as much as on low-density lipoprotein cholesterol. Combination drug therapy will usually be required. Reliable assessment of risk of coronary artery disease from lipoprotein measurements and response to therapy requires inclusion of all atherogenic lipoproteins in laboratory measurements and treatment protocols. At present this may be best accomplished by use of non-high-density lipoprotein cholesterol (total cholesterol minus high-density lipoprotein cholesterol) calculated from standard laboratory lipoprotein values. Ultimately, a more comprehensive assessment of coronary artery disease risk and appropriate therapy may include measurement of lipoprotein subclass distribution including determination of low-density lipoprotein particle concentration and sizes of the various lipoprotein particles.

Cholesteryl ester enrichment of plasma low-density lipoproteins in hamsters fed cereal-based diets containing cholesterol

Male Syrian hamsters were fed 0.02, 0.03, or 0.05% cholesterol to test the hypothesis that moderate cholesterol intake increases the cholesteryl ester content of the plasma low-density lipoproteins (LDL). Dietary cholesterol levels of 0.02%-0.05% were chosen to reflect typical human intakes of cholesterol. Hamsters were fed ad libitum a cereal-based diet (modified NIH-07 open formula) for 15 weeks. Increasing dietary cholesterol from 0.02% to 0.05% resulted in significantly increased plasma LDL and high-density lipoprotein cholesterol concentration, increased liver cholesterol concentration, and increased total aorta cholesterol content. The cholesteryl ester content of plasma LDL was determined as the molar ratio of cholesteryl ester to apolipoprotein B and to surface lipid (i.e., phospholipid + free cholesterol). Increasing dietary cholesterol from 0.02% to 0.05% resulted in significantly increased cholesteryl ester content of LDL particles. Furthermore, cholesteryl ester content of LDL was directly associated with increased total aorta cholesterol, whereas a linear relationship between plasma LDL cholesterol concentration and aorta cholesterol was not observed. Thus, the data suggest that LDL cholesteryl ester content may be an important atherogenic feature of plasma LDL.

Epidemiologic aspects of lipid abnormalities

Existing cholesterol guidelines aimed at preventing cardiovascular disease emphasize the role of total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol in lipid management decisions, with a subsidiary role for high-density lipoprotein (HDL) cholesterol in guiding treatment and little role for triglycerides. In this article, epidemiologic evidence is reviewed relating to the independent value of lipid factors in prediction of cardiovascular disease risk, including TC, LDL cholesterol, HDL cholesterol, very-low-density lipoprotein (VLDL) cholesterol and triglycerides, LDL particle size ("pattern B"), and the TC/HDL-cholesterol ratio. Several observations are highlighted. Triglycerides appear to be an independent risk factor in specific populations. Postprandial triglycerides may be superior to fasting triglycerides as a predictor of risk. LDL particle size does not have independent predictive value after adjustment for triglycerides. Particular emphasis is placed on the observation that the single most predictive lipid factor is the TC/HDL-cholesterol ratio, which implicitly incorporates information on both LDL and triglycerides in the numerator. This is the best predictor both of outcome and of treatment benefit, and its predictive value appears to be maintained into older age. It is concluded that increasing emphasis should be placed on the TC/HDL cholesterol ratio in epidemiologic analyses and in monitoring patients on therapy for dyslipidemia.

Control of lipid disorders in patients with atherosclerotic vascular disease

The primary dyslipidemias are associated with an increased incidence of atherosclerotic vascular disease in coronary, cerebral, and peripheral vessels. If nonpharmacologic therapy, such as dietary changes and aerobic exercise, fails to achieve the therapeutic goal levels for serum low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides suggested by the National Cholesterol Education Program Adult Treatment Panel, pharmacologic intervention is indicated. The choice of the class of lipid-lowering drug(s) for initial therapy and subsequent therapy depends on the nature of the dyslipidemia, e.g., hypercholesterolemia, hypertriglyceridemia, suppressed HDL cholesterol levels, or combinations of these disturbances in lipid metabolism. Appropriate therapy with the highly efficacious agents currently available significantly reduces the associated morbidity and mortality related to atherosclerosis. The clinical applications of these classes of agents are discussed here.

Low plasma ascorbic acid independently predicts the presence of an unstable coronary syndrome

OBJECTIVES

This study sought to investigate the relations between plasma antioxidant status, extent of atherosclerosis and activity of coronary artery disease.

BACKGROUND

Previous studies indicate that increased antioxidant intake is associated with decreased coronary disease risk, but the underlying mechanisms remain controversial.

METHODS

Plasma samples were obtained from 149 patients undergoing cardiac catheterization (65 with stable angina, 84 with unstable angina or a myocardial infarction within 2 weeks). Twelve plasma antioxidant/oxidant markers were measured and correlated with the extent of atherosclerosis and the presence of an unstable coronary syndrome.

RESULTS

By multiple linear regression analysis, age (p < 0.001), diabetes mellitus (p < 0.001), male gender (p < 0.001) and hypercholesterolemia (p = 0.02) were independent predictors of the extent of atherosclerosis. No antioxidant/oxidant marker correlated with the extent of atherosclerosis. However, lower plasma ascorbic acid concentration predicted the presence of an unstable coronary syndrome by multiple logistic regression (odds ratio [OR] 0.59, 95% confidence interval [CI] 0.40 to 0.89, p = 0.01). The severity of atherosclerosis also predicted the presence of an unstable coronary syndrome (OR 1.7, 95% CI 1.14 to 2.47, p = 0.008) when all patients were considered. When only patients with significant coronary disease were considered (at least one stenosis >50%), ascorbic acid concentration (OR 0.56, 95% CI 0.37 to 0.85, p = 0.008) and total plasma thiols (OR 0.52, 95% CI 0.34 to 0.80, p = 0.004) predicted the presence of an unstable coronary syndrome, whereas the extent of atherosclerosis did not.

CONCLUSIONS

These data are consistent with the hypothesis that the beneficial effects of antioxidants in coronary artery disease may result, in part, by an influence on lesion activity rather than a reduction in the overall extent of fixed disease.

L-2-Oxothiazolidine-4-carboxylic acid reverses endothelial dysfunction in patients with coronary artery disease

The effective action of endothelium-derived nitric oxide (EDNO) is impaired in patients with atherosclerosis. This impairment has been attributed in part to increased vascular oxidative stress. EDNO action is improved by administration of ascorbic acid, a water-soluble antioxidant. Ascorbic acid is a potent free-radical scavenger in plasma, and also regulates intracellular redox state in part by sparing cellular glutathione. We specifically investigated the role of intracellular redox state in EDNO action by examining the effect of L-2-oxo-4-thiazolidine carboxylate (OTC) on EDNO-dependent, flow-mediated dilation in a randomized double-blind placebo-controlled study of patients with angiographically proven coronary artery disease. OTC augments intracellular glutathione by providing substrate cysteine for glutathione synthesis. Brachial artery flow-mediated dilation was examined with high-resolution ultrasound before and after oral administration of 4.5 g of OTC or placebo in 48 subjects with angiographically documented coronary artery disease. Placebo treatment produced no change in flow-mediated dilation (7.0+/-3.9% vs. 7.2+/-3.7%), whereas OTC treatment was associated with a significant improvement in flow-mediated dilation (6.6+/-4.4% vs. 11.0+/-6.3%; P = 0.005). OTC had no effect on arterial dilation to nitroglycerin, systemic blood pressure, heart rate, or reactive hyperemia. These data suggest that augmenting cellular glutathione levels improves EDNO action in human atherosclerosis. Cellular redox state may be an important regulator of EDNO action, and is a potential target for therapy in patients with coronary artery disease.

Relationship between fat distribution and lipid and apolipoprotein profiles in young teenagers

The influence of obesity and fat distribution on serum levels of lipoprotein and apolipoprotein was investigated in 294 Japanese junior high school children (12-13 years of age). Serum levels of low-density lipoprotein cholesterol (LDLC) (P = 0.013), triglycerides (TG) (P = 0.0006), and apolipoprotein B (apoB) (P = 0.003), and the apoB/A-I ratio (P = 0.005) were significantly higher and serum levels of high-density lipoprotein cholesterol (HDLC) (P = 0.00003) and apoA-1(P = 0.003) were significantly lower in obese boys than in non-obese boys. The serum levels of TG (P = 0.013) and the apoB/A-I ratio (P = 0.011) were significantly higher and the serum levels of HDLC (P = 0.004) was significantly lower in obese girls than in non-obese girls. The LDLC/apoB ratio was lower in obese girls than in non-obese girls (P = 0.03). Obesity (> or = 20% of ideal weight) was strongly correlated with the serum levels of lipids and apolipoproteins in boys; this relationship was less clear in girls. The degree of obesity and the body mass index (BMI) were more strongly correlated with serum levels of lipids and apolipoproteins in boys than in girls. In boys, atherogenic lipoproteins and apolipoproteins, such as LDLC and apoB, showed a stronger correlation with the thickness of the triceps skinfold, while in girls the anti-atherogenic lipoproteins and apolipoproteins, such as HDLC and apoA-I, showed a stronger correlation with both the triceps and the subscapular skinfold thicknesses. In girls the relationships between the BMI and the degree of obesity and the thickness of the subscapular skinfold (S) thickness were similar to the relationships between those parameters and the triceps skinfold (T) thickness. In boys, these parameters showed a stronger correlation with the subscapular skinfold thickness than with the triceps skinfold thickness. The correlation coefficients for the relationships between skinfold thickness and lipid and apolipoprotein levels were similar to the coefficients for the relationships between skinfold thicknesses and the severity of obesity and the BMI. The distribution of central-type fat accumulation, which is indicated by the thickness of the subscapular skinfold, the S/T ratio and S-T value, was inversely correlated with the HDLC level in both boys and girls. The degree of obesity was strongly correlated with the atherogenic lipoprotein profile in boys, in part because the subscapular skinfold thickness was strongly correlated with the degree of obesity and the BMI. In girls, the correlations between indices of central-type obesity and atherogenic lipid and apolipoprotein profiles were stronger than in boys. These data suggest that childhood obesity may be an early cardiovascular risk factor.

Evidence for a role of tumor necrosis factor alpha in disturbances of triglyceride and glucose metabolism predisposing to coronary heart disease

Elevated plasma levels of triglyceride-rich lipoproteins, a decreased high-density lipoprotein (HDL) cholesterol concentration, hyperinsulinemia, and impaired fibrinolytic function frequently aggregate in patients with premature coronary heart disease (CHD). Experimental studies suggest that the cytokine tumor necrosis factor alpha (TNFalpha) produced by adipocytes plays a part in the regulation of triglyceride and glucose metabolism. The present study examined whether TNFalpha is implicated in these metabolic and fibrinolytic disturbances in young postinfarction patients. TNFalpha levels were determined in two groups of young (age <45 years) male postinfarction patients (n = 92 and 60) and in matched, population-based control subjects (n = 63). Plasma TNFalpha was higher in patients than in controls (4.1 +/- 1.6 v2.5 +/- 0.4 pg/mL, P < .0001). In hyperlipidemic patients, TNFalpha levels correlated significantly with the concentrations of very-low-density lipoprotein (VLDL) triglyceride and cholesterol and negatively with HDL cholesterol. Treatment with bezafibrate decreased VLDL triglycerides and increased HDL cholesterol, but did not affect TNFalpha levels. The TNFalpha concentration also correlated significantly with fasting glucose and proinsulin concentrations, as well as glucose and proinsulin levels after glucose ingestion. In contrast, no relations were found with the insulin level or degree of insulin resistance. The present results provide clinical evidence for a basic role of TNFalpha in hypertriglyceridemia, glucose intolerance, and the etiology of premature CHD.

Fractional esterification rate of cholesterol in high density lipoprotein (HDL) can predict the particle size of low density lipoprotein and HDL in patients with coronary heart disease

Fractional esterification rate of cholesterol in high density lipoprotein (HDL) (FER[HDL]) can predict the size distribution and physicochemical characteristics of HDL in plasma. In the present study, we investigated the correlation of FER(HDL) with the particle size of low density lipoprotein (LDL) (LDL-size) in 111 patients (81 males and 30 females) with coronary heart disease (CHD). The correlations of FER(HDL) and LDL-size with conventional lipid and lipoprotein parameters were also studied. FER(HDL) was closely associated with LDL-size (males: r = -0.618, females: r = -0.629, P < 0.001). Plasma levels of TG, HDL-cholesterol (HDL-C), HDL2-cholesterol (HDL2-C) and apo B were also associated with LDL-size in male CHD patients (r = -0.534, 0.314, 0.358, and -0.482, P < 0.01 or 0.001), while plasma levels of TG and apo B were associated with LDL-size in female patients (r = -0.350 and -0.348, P < 0.05). In a stepwise multiple regression analysis, FER(HDL) alone accounted for 38 and 40% of the variability in LDL-size in male and female CHD patients, respectively. Other parameters accounted for an additional 6-10%. With respect to the relation between FER(HDL) and HDL subfractions, FER(HDL) related only to HDL2-C (males: r = -0.640, females: r = -0.652, P < 0.001). This result suggests that FER(HDL) is better able to predict the presence (or absence) of large HDL, rather than that of small HDL. All these data taken together, suggest that FER(HDL) is a useful tool to predict the particle size of both LDL and HDL, even in CHD patients.

Characteristics of coronary artery disease and lipoprotein abnormalities in patients with heterozygous familial hypercholesterolemia associated with diabetes mellitus or impaired glucose tolerance

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of serum low density lipoprotein (LDL) cholesterol and premature coronary atherosclerosis. In order to elucidate the influence of abnormal glucose metabolism on the development of coronary artery disease (CAD) in FH patients, we examined the prevalence of CAD and characteristics of lipoprotein abnormalities in patients with heterozygous FH who were accompanied by diabetes mellitus (DM) or impaired glucose tolerance (IGT). The subjects of the present study were 150 patients with heterozygous FH, all over 40 years of age. Oral glucose tolerance tests demonstrated that 15 patients had DM and 27 had IGT. The combination of DM or IGT with FH was associated with a further increase in the prevalence of CAD (DM:IGT:normal glucose tolerance (N), 87:59:43%). Furthermore, the prevalence of the stenoses in the distal coronary arteries was significantly higher in the DM group than in the N group, while there was no significant difference in the prevalence of proximal and middle lesions. Serum triglyceride levels were significantly higher in the DM and IGT groups than in the N group (P < 0.01, DM versus N group; P < 0.01, IGT versus N group), while total cholesterol levels were not significantly different. When lipoproteins were analyzed by polyacrylamide gel electrophoresis, the frequency of midband appearance, which implies an increase in remnant lipoproteins, was significantly higher in the DM and IGT groups than in the N group (DM:IGT:N, 87:72:29%, P < 0.01, DM versus N group; P < 0.01, IGT versus N group). Ultracentrifugation analysis of lipoproteins revealed that intermediate density lipoprotein cholesterol was increased in DM and IGT groups compared with the N group. These data suggest that abnormal glucose metabolism may accelerate the development of CAD in FH patients due to an increase in atherogenic remnant lipoproteins in addition to high concentration of LDL. Special attention should be paid in the treatment of FH patients with impaired glucose metabolism, to avoid the advancement of coronary atherosclerosis.

Association of lipoprotein cholesterol and triglycerides with the severity of coronary artery disease in men and women

The differences between the lipid profiles of male and female patients and the effect of plasma lipids on the extent of coronary artery disease were evaluated in 122 angiographically assessed coronary artery disease patients (95 males and 27 females) and 60 controls. Both male and female patients had lower HDL-cholesterol and higher total cholesterol, LDL-cholesterol, triglyceride, VLDL-cholesterol and VLDL-triglyceride concentrations than the controls. The VLDL lipid values did not differ significantly between the male patients with different extent of CAD, whereas the VLDL lipid values of female patients tended to increase with an increasing severity of CAD. High Lp(a) (> or = 35 mg/dl) values were more prevalent in patients with > 50% coronary stenosis compared to patients with < 50% stenosis and the controls (29%, 17% and 12%, respectively). The apolipoprotein E phenotypes and epsilon allele frequencies were similar in the patients and the controls. Low HDL-cholesterol and high LDL-cholesterol are CAD risk factors for both sexes. For women, elevated VLDL-triglycerides seem to be an additional risk factor for CAD.

Serum and bile lipid levels in patients with and without gallstones

The aim of the present study was to investigate predisposing factors that lead to the formation of gallstones. In a group of 70 patients (51 with gallstones and 19 without, 20 possible risk factors were studied: percent of ideal body weight, the presence of superoxide dismutase in erythrocytes and in serum, lipid peroxide in serum, total serum cholesterol (Ch), high-density lipoprotein (HDL)-cholesterol (Ch), low-density lipoprotein (LDL)-Ch, very low-density lipoprotein (VLDL)-Ch, serum triglyceride (TG), HDL-TG, LDL-TG, VLDL-TG, serum bile acids (lithocholic acid, deoxycholic acid, chenodeoxy cholic acid, ursodeoxy-cholic acid, and cholic acid) and serum apolipoproteins (apo A-1, apo B-100, and apo A-1/apo B-100). Levels of apo B-100 and serum insulin in patients with gallstones were strikingly higher, and superoxide dismutase in erythrocytes was significantly lower than in individuals with no gallstones. Apo A-1 and HDL-Ch were also higher and LDL-Ch was lower in the gallstone group, albeit non-significantly so (P > 0.05) by t-test. However, Apo A-1, HDL-Ch, and LDL-Ch showed remarkably good discriminatory power in stepwise discriminant analysis of the 20 factors. Bile lipid composition was also measured and the cholesterol saturation index was calculated, but no significant differences were seen between the two groups. The results demonstrate that serum lipid patterns differ to some extent in patients with and without gallstones. Lipid derangement may contribute to the development of gallstone disease.