Selective determination of cholesterol in high density lipoprotein subfractions (HDL2 and HDL3) in patients with cerebral and peripheral arteriosclerosis

High-density lipoprotein subclasses and their relationship to cardiovascular disease

OBJECTIVE

To assess the clinical utility of measuring high-density lipoprotein (HDL) subfractions to assess coronary heart disease (CHD) risk.

METHODS

Literature review of 80 published investigations.

RESULTS

Measurements of HDL2b by gradient gel electrophoresis provided more consistent evidence of CHD risk than measurement of HDL2 cholesterol. Five of the seven studies that compared the extent or progression of atherosclerosis with gradient gel electrophoresis estimates of HDL subclasses (71%) assigned statistical significance to HDL2b. Ten of the 11 case-control comparisons (91%) reported lower HDL2b in cases. In contrast, of the 16 association studies relating HDL2 cholesterol and HDL3 cholesterol to extent of disease, five reported no significant relationships with either subfraction, two reported significant relationships with both HDL2 and HDL3 cholesterol, four reported significant relationships with HDL2 but not HDL3 cholesterol, and five reported relationships with HDL3 but not HDL2 cholesterol. Forty-five percent of the case-control comparisons reported that both HDL2 cholesterol and HDL3 cholesterol were significantly lower in cases than controls, 17% failed to find significance for either subfraction, and the remainder reported significantly lower values in cases for HDL2 cholesterol only (26%) or HDL3 cholesterol only (11%). On average, the case-control differences were similar for HDL2 (-0.12 ± 0.01 mmol/L) and HDL3 cholesterol (-0.10 ± 0.02 mmol/L), although relative to controls, the percent reduction was twice as great for HDL2 (-25.7 ± 2.9%) than HDL3 cholesterol (-12.1 ± 1.5%). Eight prospective studies were identified and four reported that both HDL2 and HDL3 predicted lower risk for CHD, one reported reductions in risk for HDL2 but not HDL3 cholesterol, and three reported reductions in risk for HDL3 but not HDL2 cholesterol. None of the prospective studies show that measurements of HDL cholesterol subfractions improve the identification of persons at risk.

CONCLUSIONS

HDL2 and HDL3 cholesterol do not distinguish cardioprotective differences between HDL subclasses. More extensive characterization of HDL particles by one or two dimensional gel electrophoresis, ion mobility, or ultracentrifugation may provide more specific information about CHD risk than the measurement of HDL cholesterol, HDL3 cholesterol, or HDL2 cholesterol.

Effects of transdermal estrogen replacement therapy on plasma levels of nitric oxide and plasma lipids in postmenopausal women

OBJECTIVE

Our purpose was to assess the effects of transdermal estrogen replacement therapy (TERT) on plasma levels of nitric oxide (NO) and plasma lipids in postmenopausal women.

MATERIALS AND METHODS

The study designed as a randomized, double-blind, placebo-controlled trial, involved 43 postmenopausal healthy women who had previously undergone hysterectomy. Women received either transdermal 100 microg 17beta-estradiol (Climara forte TTS) or placebo once a week for 3 months. Plasma levels of NO metabolites, estradiol (E2), total cholesterol (TC), triglicerides (TG), low-density lipoproteins (LDL), high-density lipoproteins (HDL), HDL2 and HDL3 were measured in blood samples of all women which were collected before, after 24 h and after 3 months of therapy.

RESULTS

We found significantly increased NO levels 24 h after therapy in TERT group. Moreover significantly higher NO levels were determined at 3rd month of therapy. Serum HDL and HDL2 levels of ERT group were significantly increased at 3rd month of therapy. Alteration of serum levels of HDL3, LDL and TC were not significantly different in groups. TG levels were significantly decreased in TERT group.

DISCUSSION

NO-related mechanism may help to explain the cardio-protective effect of TERT in the postmenopausal period. TERT seems to have favorable effects on plasma lipids in surgical menopausal women.

Lipids and other risk factors selected by discriminant analysis in symptomatic patients with supra-aortic and peripheral atherosclerosis

BACKGROUND

Different patterns of risk factors might be related to the involvement of specific vascular districts by atherosclerosis. In this sense, many investigations have addressed coronary artery disease, whereas extracoronary atherosclerosis has received less extensive attention.

METHODS AND RESULTS

Vascular risk factors, with particular attention to lipid parameters (total cholesterol [TC]; triglycerides; high density lipoprotein cholesterol [HDL-C], HDL2 and HDL3 cholesterol [HDL2-C, HDL3-C]), were evaluated by means of univariate and multivariate (discriminant) analysis in a group of 169 patients (128 men and 41 women; mean ages, 58 +/- 7 and 62 +/- 7 years, respectively) with clinically and angiographically demonstrated atherosclerosis of the supra-aortic trunk and/or lower limbs. Patients with coronary artery disease were excluded from this study. The control group consisted of 140 age- and sex-matched individuals. By univariate analysis, smoking was more closely associated with peripheral atherosclerosis, whereas blood pressure was higher in patients with supra-aortic disease. Unrecognized diabetes mellitus was a frequent finding in patients with peripheral disease. The percentage of hyperlipidemias was fourfold higher in patients than in control subjects, with differences consisting of higher triglycerides and lower HDL-C, HDL2-C, and HDL3-C concentrations. By discriminant analysis, high correct classification (CC) rates were achieved in the various patient subgroups on the basis of variables selected from the statistical function. In male patients with peripheral disease, the variables HDL-C, smoking, diastolic blood pressure, uric acid, and glucose, in that order, yielded a CC in 90.4% of the cases; in female patients, smoking, TC/HDL-C, and body mass index gave a CC rate of 95.9%. In men with cerebral disease, the selected variables TC/HDL-C, diastolic blood pressure, and TC yielded a CC of 90.7%; in women, uric acid, TC/HDL-C, and fibrinogen levels produced a CC rate of 89.2%.

CONCLUSIONS

Risk profiles in atherosclerosis of the supra-aortic trunks and lower limbs seem to differ in relation to gender and circulatory district involved. The importance of lipid parameters, in particular HDL-C, HDL2-C, and TC/HDL-C, as extracoronary risk factors is further confirmed.

Lipoprotein abnormalities in patients with extra-coronary arteriosclerosis

Serum levels of lipids, lipoproteins and apolipoproteins A-I and B were evaluated in 102 patients (75 males and 27 females; ages 58 +/- 8 and 61 +/- 7 years (mean +/- SD), respectively) with arteriosclerosis of the lower limbs of supra-aortic trunks. Compared to findings in 64 healthy, age-matched control subjects, male patients in both groups had significantly higher serum triglyceride levels (+42%, P less than 0.05), while female patients with lower limb arteriosclerosis showed significantly increased cholesterol and triglyceride concentrations (+19%, P less than 0.01 and +82%, P less than 0.05, respectively). LDL-triglycerides were also increased in all patients. HDL-cholesterol was significantly decreased in male patients with arteriosclerosis of the lower limbs (-27%, P less than 0.01) and the supra-aortic trunks (-28%, P less than 0.01), and in females of both groups (-26%, P less than 0.01 and -20%, P less than 0.01, respectively); in terms of percent, HDL2-cholesterol was reduced 2-fold compared to HDL3-cholesterol. Patient apolipoprotein A-I and B levels were unchanged. In male and female patients, correlations between triglycerides and HDL-cholesterol as well as HDL2-cholesterol were negative, but not significant; on the other hand, both correlations were negative and significant in male controls, while only the correlation between triglycerides and HDL2-cholesterol was negative and significant in the female controls. Since HDL-cholesterol, and in particular HDL2-cholesterol, concentrations seem closely related to the intravascular catabolism of triglyceride-rich lipoproteins, the absence of a significant correlation between these parameters in the patients suggests a possible alteration in this metabolic process.

Serum lipoprotein pattern variations in dementia and ischemic stroke

Blood levels of triglycerides, total cholesterol, isolated lipoprotein fractions (VLDL-LDL- and HDL-cholesterol) and apoproteins (Apo-A1 and Apo-B) were examined in multi-infarct dementia, senile dementia of the Alzheimer type, ischemic stroke associated with carotid atherosclerosis and in control subjects. Forty patients divided into 10 consecutive patients for each group were studied. Alzheimer patients showed mean total cholesterol and Apo-B values significantly higher than control subjects. Apo-B was significantly higher in stroke patients than in controls. The mean lowest HDL-cholesterol (HDL-c) value was observed in stroke patients. No significant differences in mean HDL-c levels were found between patients with multi-infarct and Alzheimer dementia.

Individual variation in susceptibility to extracranial carotid atherosclerosis

Risk factors for coronary disease were assessed and noninvasive methods were used to quantitate the extent of extracranial carotid atherosclerosis in 382 patients free of cerebrovascular symptoms. The ages of the participants ranged from 27 to 80 years. There were 183 men and 199 women, 30 black and 352 white persons. All patients had heart disease symptoms and were hospitalized for coronary angiography. Correlation of risk factors with extent of extracranial carotid atherosclerosis in this series of patients undergoing coronary angiography uncovered individual variability in relationships between risk factors and carotid atherosclerosis that depended on coronary status. Risk factors for carotid atherosclerosis in patients with and without coronary disease differed. Age and hypertension were independently related to carotid atherosclerosis in patients with, as well as those without, coronary disease. However, other risk factors were related to carotid atherosclerosis in only one group or the other. Risk factors correlated strongly with carotid atherosclerosis in patients with coronary disease (r2 = 0.41) but poorly in those with no coronary disease (r2 = 0.21). Certain risk factors (age, pack years of smoking, left ventricular hypertrophy) related differently to the extent of carotid atherosclerosis in patients with, than in those without, coronary disease. Clarification of the role of coronary status in the carotid atherosclerosis response to risk factors may partly explain the results of certain population-based studies that have related race, gender, and other risk factors to carotid atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between blood lipids, lipoproteins, and cerebrovascular atherosclerosis. A review

Although blood lipids and lipoproteins are strongly related to coronary atherosclerosis, their association with cerebrovascular atherosclerosis is less clear. A review of more than 20 publications in which a relation was sought between plasma lipid and lipoprotein concentrations and cerebrovascular atherosclerosis leads to the general conclusion that such a relation exists and that it is stronger in older than in younger individuals. A relation was found between blood lipids and/or lipoproteins and the extent and/or severity of cerebrovascular atherosclerosis in all but three of 26 reviewed studies. However, the specific nature of the relation is obscure because the various studies cannot easily be compared with one another. Interstudy variations in lipoprotein fraction analyzed, methodology for the analysis of lipids and lipoproteins, arterial segment examined, population sampled, control selection in case-control studies, statistical analytic approach taken, and methodology for the assessment of arterial disease preclude pooled analyses. There is a clear need for further evaluation of this relation using standardized and up-to-date methodologies both for analyses of lipids and lipoproteins and for assessment of cerebrovascular disease in symptom-free volunteers as well as in symptomatic patients.

Risk factors for extracranial carotid artery atherosclerosis

We related risk factors, cardiovascular symptoms, and coronary status to the extent of extracranial carotid atherosclerosis as measured by B-mode ultrasonography in 376 volunteers hospitalized for elective coronary angiography. In a first analysis, we correlated risk factors and cardiovascular symptoms with carotid atherosclerosis. Univariate analysis showed that relations between many continuous risk factors and carotid atherosclerosis were graded and consistent for men and women. Multivariate analysis identified 6 significant variables (age, hypertension, pack-years smoked, and inversely, plasma concentrations of high density lipoprotein cholesterol and uric acid, and Framingham Type A score) that together accounted for 35% of the variability in extent of carotid atherosclerosis. In a second multivariate analysis, addition of coronary status (presence or absence of coronary stenosis as evaluated by coronary angiography) to the roster of candidate independent variables produced a new equation that accounted for an additional 5% of the variability in carotid atherosclerosis extent. Although much of the variability in extent of carotid atherosclerosis remains unexplained, these data define an association between coronary and carotid atherosclerosis that depends partly on shared exposure of both arteries to the same risk factors. They are also consistent with the concept that as yet undiscovered risk factors and/or genetic (e.g., arterial wall) factors common to both arterial beds also contribute to the relation between coronary and carotid atherosclerosis in human beings.