Hypertriglyceridemic hyperapoB in type 2 diabetes

OBJECTIVES: Much less attention has been paid to LDL in type 2 diabetes than to VLDL or HDL. In particular, there are few data on apoB levels in these patients. Moreover, most reports have focused on mean lipoprotein levels and consequently there is little information on the frequencies of the various dyslipidemic phenotypes. RESEARCH DESIGN AND METHODS: Plasma and lipoprotein lipids, apoB and apoA1 were measured by standardized methods. LDL particle size was determined by PAGE. The total cohort was divided into phenotypes by two different methods. The first was based on triglycerides (> or = or <1.5 mmol/l) and LDL cholesterol (> or = or <4 mmol/l), whereas the second was based on triglycerides (> or = or <1.5 mmol/l) and apoB (> or = or <120 mg/dl). RESULTS: For the overall cohort, plasma triglycerides were elevated (2.13 +/- 1.6 mmol/l), total and LDL cholesterol were normal (5.34 +/- 1.1 and 3.28 +/- 0.88 mmol/l, respectively), and peak LDL size was reduced (252.9 +/- 5.8 A). HDL cholesterol was between the 25th and 50th percentiles of the general population (1.12 +/- 0.36 mmol/l). The average level of apoB was 114 +/- 29 mg/dl, a value that is between the 50th and 75th percentiles of the general population and is higher than that for LDL cholesterol, which was between the 25th and the 50th percentiles of the population. The results of the phenotyping analysis were as follows. Using the conventional approach, only 23% has abnormal LDL, i.e., an elevated LDL cholesterol level. Using the new approach, almost 40% has an elevated apoB and therefore an elevated LDL particle number. Only 12.8% has combined hyperlipidemia based on the conventional approach, whereas almost one-third had the equivalent, hypertriglyceridemic hyperapoB-based on the new algorithm. The severity of the dyslipoproteinemia in this group was noteworthy. Although the average LDL cholesterol was 3.91 mmol/l, a value just below the 75th percentile of the general population, the average apoB was 145 mg/dl, a value that approximates the 95th percentile of the population. CONCLUSIONS: The dyslipidemic profile of patients with type 2 diabetes is not uniform. A substantial group have normal lipids and normal LDL particle number and size whereas others have markedly abnormal profiles. Diagnosis based on triglycerides and apoB rather than triglycerides and LDL cholesterol revealed that more than one in five had hypertriglyceridemic hyperapoB, which is characterized by hypertriglyceridemia, marked elevation of LDL particle number, small dense LDL, and low HDL, a constellation of abnormalities that is associated with markedly accelerated atherogenesis and therefore justifies intensive medical therapy.     

Controlling cholesterol levels through diet

High blood cholesterol levels are a major risk factor for coronary artery disease. Recent studies have shown that a cholesterol-lowering diet has a principal role in reducing coronary events in humans. A diet low in saturated fat and cholesterol is recommended for patients with a cholesterol level of more than 240 mg/dl or a level of between 200 and 239 mg/dl plus other risk factors. Measurement of low-density lipoprotein and high-density lipoprotein cholesterol levels provides a baseline value by which to gauge progress. Periodic assessment by the physician will give an indication of patient compliance. For patients who do not achieve desired goals within six months, drug therapy may be necessary.     

Comparison of the effects of guanabenz and hydrochlorothiazide on plasma lipids

The effects of hydrochlorothiazide (HCTZ) and guanabenz monotherapy on blood pressure and serum lipoprotein levels were compared in a 14-week, randomized, parallel, double-blind multicenter study of 218 outpatients with mild hypertension. Mean supine blood pressure decreased 13/9 mm Hg in the guanabenz group and 17/11 mm Hg in the HCTZ group, changes that were significantly (p less than 0.01) different from baseline but not significantly different between the two treatment groups. Significant (p less than 0.01) mean decreases in total cholesterol and low-density lipoprotein (LDL) cholesterol levels (of 9 mg/dl and 4 mg/dl from baseline values) occurred during guanabenz treatment; HDL cholesterol levels fell by an average of 4 mg/dl. In the HCTZ group, triglyceride levels were significantly (p less than 0.01) increased by 13 mg/dl, and HDL cholesterol levels fell by 2 mg/dl. The change in LDL cholesterol levels, but not HDL cholesterol levels, was significantly different between guanabenz and HCTZ periods. The results show that guanabez, although providing effective blood pressure control that is comparable to that of HCTZ, has more favorable effects on lipoproteins.     

Present status of serum lipid levels in Beijing professional populations and its trend of changes over 15 years--a collaborative study of seven research and clinical laboratories in Beijing

BACKGROUND: China's economy has been growing rapidly since 1980, which may have affected blood lipid levels. We carried out a study on serum lipid levels and prevalence of lipid abnormalities in Beijing professional populations in 2001-2002 and assessed the changing trends of lipid levels by comparing the results with that of a similar study in 1984-1986. METHODS: The study population included 31,068 government employees, medical and educational workers and scientific research personnel (male/female 6:4). All participants had physical examination and blood chemistry tests. Lipid parameters analyzed included total cholesterol, low- and high-density lipoprotein (LDL and HDL) cholesterol and triglyceride. RESULTS: Total cholesterol, LDL cholesterol and triglyceride concentrations increased significantly as compared with the 1984-1986 study, but the variations of lipid levels with age and sex remained unchanged. Age-adjusted prevalence of dyslipidemia and its distribution in different sexes and age groups were statistically analyzed. Comparing the results with the data of the US in the 1990s, total cholesterol concentration was lower by 16 mg/dl in men and 18 mg/dl in women, whereas LDL cholesterol concentration was lower by 20 mg/dl in men and 15 mg/dl in women. HDL cholesterol was significantly higher than the US in both genders. CONCLUSIONS: The mean levels of total cholesterol (LDL cholesterol ) increased rapidly in the 1980s, stabilized and descended slightly in 1990s. Coronary lipid risk level in Beijing professional populations is significantly lower than in the US.     

Dyslipidemias among normoglycemic members of familial NIDDM pedigrees.

OBJECTIVE--To examine the hypothesis that hyperinsulinemia among relatives of NIDDM probands will increase the prevalence of DLPs, we measured insulin levels and examined the frequency of DLPs among NIDDM pedigree members. RESEARCH DESIGN AND METHODS--We performed 2-h 75-g OGTTs and measured lipid and insulin levels of 287 family members and 86 spouses from 16 large Utah pedigrees ascertained for greater than or equal to 2 siblings with NIDDM. RESULTS--One-hour insulin levels were higher among 206 family members with NGT than among 65 NGT spouses (483.3 vs. 361.7 pM, P = 0.05). Among the NGT family members, 32% had cholesterol levels at or above the age- and sex-specific 90th percentile level defined by the LRC studies, 33% had HDL levels less than or equal to 10th percentile, and 20% had triglyceride levels greater than or equal to 90th percentile. DLP (any of the three abnormalities) was found among 58% of NGT family members, which was significantly higher than the expected 27% (P less than 0.00001) and the prevalence among spouses of 45% (P less than 0.05). By NCEP criteria for hyperlipidemia, 40% of family members met criteria for diet and/or pharmacological therapy. CONCLUSIONS--Normoglycemic members of NIDDM pedigrees have a high prevalence of DLPs, which approaches the prevalence in patients with NIDDM. Our data suggest that members of NIDDM pedigrees should be screened carefully for lipid abnormalities.     

Effects of a new calcium channel blocker, TA 3090, on serum lipoprotein levels in mild to moderate essential hypertension

The 25 hypertensive patients received 20 to 40 mg of TA 3090 daily for 12 weeks. Blood pressures declined significantly during treatment, from a mean of 162/98 to 145/88 mmHg. There were no significant changes in levels of total or very low-density lipoprotein cholesterol or triglyceride, in levels of low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, HDL2 cholesterol, HDL3 cholesterol, or in levels of apolipoprotein (apo) B, C-II, C-III, or E. Apo A-I and A-II levels increased significantly from 130 and 29.2 mg/dl before treatment to 152 and 31.4 mg/dl at 12 weeks. Mean serum creatinine levels decreased significantly from 0.92 to 0.80 mg/dl. No other drug-related changes in laboratory test results or side effects were noted. It is concluded that TA 3090 is a safe and effective treatment for mild to moderate hypertension.     

Increased expression of apolipoprotein E in transgenic rabbits results in reduced levels of very low density lipoproteins and an accumulation of low density lipoproteins in plasma.

Transgenic rabbits expressing human apo E3 were generated to investigate mechanisms by which apo E modulates plasma lipoprotein metabolism. Compared with nontransgenic littermates expressing approximately 3 mg/dl of endogenous rabbit apo E, male transgenic rabbits expressing approximately 13 mg/dl of human apo E had a 35% decrease in total plasma triglycerides that was due to a reduction in VLDL levels and an absence of large VLDL. With its greater content of apo E, transgenic VLDL had an increased binding affinity for the LDL receptor in vitro, and injected chylomicrons were cleared more rapidly by the liver in transgenic rabbits. In contrast to triglyceride changes, transgenic rabbits had a 70% increase in plasma cholesterol levels due to an accumulation of LDL and apo E-rich HDL. Transgenic and control LDL had the same binding affinity for the LDL receptor. Both transgenic and control rabbits had similar LDL receptor levels, but intravenously injected human LDL were cleared more slowly in transgenic rabbits than in controls. Changes in lipoprotein lipolysis did not contribute to the accumulation of LDL or the reduction in VLDL levels. These observations suggest that the increased content of apo E3 on triglyceride-rich remnant lipoproteins in transgenic rabbits confers a greater affinity for cell surface receptors, thereby increasing remnant clearance from plasma. The apo E-rich large remnants appear to compete more effectively than LDL for receptor-mediated binding and clearance, resulting in delayed clearance and the accumulation of LDL in plasma.     

Simvastatin in the treatment of hypercholesterolemia in elderly patients

Twenty elderly (mean age, 69 years), hypercholesterolemic patients (low-density lipoprotein [LDL] levels greater than or equal to 160 mg/dl) were supplied a lipid-lowering diet for one month and then received 10 mg of simvastatin daily for 12 months. Total cholesterol levels fell significantly, from 304.6 mg/dl at baseline to 277.4 mg/dl after one month on the diet, to 245.9 mg/dl after one month of simvastatin, and to 216.1 mg/dl after two months of simvastatin; total cholesterol levels remained significantly lower (221.6 mg/dl at month 12). LDL levels decreased significantly, from 217.6 mg/dl at baseline to 130.4 mg/dl at month 12. High-density lipoprotein levels increased significantly only at months 2 and 3. Apolipoprotein (apo) A levels increased significantly, from 147.2 mg/dl at baseline to 217.9 mg/dl at month 12. There were no significant changes in triglyceride or apo B levels. No changes in blood pressure, heart rate, or body weight or in results of laboratory tests were noted. Few side effects were reported. It is concluded that simvastatin is safe and effective in the treatment of hypercholesterolemia in elderly patients.     

正常(或低)胆固醇冠心病患者的脂蛋白谱特点

目的研究血清总胆固醇（ＴＣ）正常或低于平均水平的冠心病（ＣＨＤ）患者的脂蛋白谱特点。方法观察诊断明确的男性ＣＨＤ２２５例，以年龄配对、生活水平相似的健康男子２２５例为对照。两组中均排除与脂代谢有关的疾病及用药。对血脂作多指标［１４项，包括载脂蛋白（ａｐｏ）８项］综合分析。结果ＣＨＤ患者中ＴＣ高于５．１７ｍｍｏｌ／Ｌ者１０８例（４８％），低于此水平者１１７例（５２％）。高ＴＣ组的血脂特点以低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）和ａｐｏＢ增高为主，低ＴＣ组（ＴＣ平均４．４１ｍｍｏｌ／Ｌ，相应的对照组为４．８１ｍｍｏｌ／Ｌ）的特点是高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）及其亚类明显偏低，尤以ａｐｏＡＩ低下最明显。多数ＨＤＬ－Ｃ低的病例并无甘油三酯增高，部分病例以低ＨＤＬ（包括ＨＤＬ－Ｃ，ａｐｏＡＩ、ＡＩ）为单一的血脂异常。逐步回归分析优选判断ＣＨＤ的指标，在低ＴＣ组首选是ａｐｏＡＩ，其次为脂蛋白（ａ）；但高ＴＣ组以ａｐｏＢ为首选。结论低ＴＣ组在ＬＤＬ致动脉硬化作用明显减弱的情况下，低ＨＤＬ成为主要的（独立的）脂类危险因素     

Abnormalities in very low, low and high density lipoproteins in hypertriglyceridemia. Reversal toward normal with bezafibrate treatment.

The effects of triglyceridemia on plasma lipoproteins were investigated in 16 hypertriglyceridemic (HTG) subjects (222-2,500 mg/dl) before and after the initiation of bezafibrate therapy. Bezafibrate caused a mean reduction of 56% in plasma triglyceride and increased the levels of lipoprotein and hepatic triglyceride lipases by 260 and 213%, respectively. The natures of very low density lipoprotein (VLDL), isolated at plasma density and of low and high density lipoprotein (LDL and HDL), separated by zonal ultracentrifugation, were determined. HTG-LDL appears as multiple fractions whereas HTG-HDL is seen predominantly as HDL3. HTG-VLDL is relatively poor in apoproteins and triglycerides but enriched in free and esterified cholesterol. HTG-LDL (main fraction) is depleted of free and esterified cholesterol but enriched in apoprotein and triglyceride. It is also denser and smaller than normal. HTG-HDL3 is denser than N-HDL3 and demonstrates compositional abnormalities similar to those of HTG-LDL. With the reduction of the VLDL mass, all abnormalities revert towards normal. This is accompanied by an increase in LDL-apoprotein B and cholesterol levels, which indicates an increased conversion of VLDL to LDL. Significant correlations between plasma triglyceride and the degree of all abnormalities are shown. The data obtained during treatment corroborate these relationships. The observations support the concept that most abnormalities reflect the degree of triglyceridemia. We suggest that plasma core-lipid transfer protein(s) is an effector of the abnormal cholesteryl ester distribution. Its prolonged action on increasingly large and slowly metabolized VLDL populations would entail a correspondingly excessive transfer of cholesteryl ester to VLDL and of triglyceride to LDL and HDL. It is calculated that, in moderate HTG, LDL and HDL contain only 50% of the normal cholesterol load. It is suggested that cholesteryl ester redistribution in HTG might be important in regulating metabolic events.     

Lipoprotein composition and HDL particle size distribution in women with non-insulin-dependent diabetes mellitus and the effects of probucol treatment

To further characterize the spectrum of potentially atherogenic disturbances in lipoprotein composition in non-insulin-dependent diabetes mellitus (NIDDM), we have studied a subset of women with NIDDM before and after treatment with the lipophilic lipid-lowering drug probucol (1 gm day), which we have shown corrects certain compositional abnormalities these women share with subjects who have hypercholesterolemia. Before treatment, the NIDDM group had a somewhat higher plasma triglyceride level (154 +/- 58.3 mg/dl, vs control, 80.0 +/- 21 mg/dl [mean +/- SD]; p less than 0.025) than controls but their cholesterol and high-density lipoprotein cholesterol (HDL-C) levels did not differ from control levels. A number of significant disturbances, however, were present in the surface and core lipid composition of their lipoproteins. Although the cholesterol content of NIDDM low-density lipoprotein (LDL) was similar to that of controls, its content of sphingomyelin and phosphatidylinositol plus phosphatidylserine and sphingomyelin-to-lecithin ratio all were significantly reduced. Moreover, their very-low-density lipoprotein (VLDL) and HDL2 tended to have reduced amounts of free (unesterified) cholesterol (FC) relative to lecithin, and their HDL2 and HDL3 tended to be triglyceride enriched. Probucol therapy resulted in significant decreases in total plasma cholesterol (-15%), FC (-28%), HDL-C (-22%), and triglyceride (-16%) and in apoproteins A-I, B, and E (apo A-I, B, and E), without changing diabetic control (before probucol: hemoglobin A1, cholesterol, 10.7% +/- 2.7%; after probucol: 10.9% +/- 3.0%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Lipid effects of celiprolol, a new cardioselective beta-blocker, versus propranolol

The metabolic effects of celiprolol, a new beta-adrenoceptor blocking agent with intrinsic sympathomimetic activity and alpha 2-blocking properties, were evaluated in a series of patients with hypertension, both with and without hyperlipidemia. Propranolol was tested as the reference drug in a randomized double-blind trial. Of the 35 patients of both sexes who completed the study, 17 were hyperlipidemic (low-density lipoprotein cholesterol greater than or equal to 170 mg/dl) and 18 were normolipidemic. Both drugs exerted a similar hypotensive effect after gradual dose adjustment; however, propranolol reduced heart rate to a higher extent (-20.5%) than celiprolol (-7.7%). Propranolol determined a significant rise of total and very low-density lipoprotein (VLDL) associated triglyceridemia, whereas high-density lipoprotein cholesterol (HDL cholesterol) levels and the total cholesterol/HDL cholesterol ratios were significantly depressed, particularly in hyperlipidemic patients. Celiprolol, in contrast, slightly decreased triglyceridemia (significantly in the hyperlipidemic group at week 12) and caused a 5% increase of the HDL cholesterol levels. The total cholesterol/HDL cholesterol ratio was reduced by celiprolol at week 16 in both hyperlipidemic and normolipidemic patients. The effects of the two beta-adrenoceptor blockers on HDL cholesterol and triglyceride levels differed significantly after 12 and 16 weeks of treatment, which confirm the divergent metabolic effects of the two agents.     

Effects of gamma-oryzanol on serum lipids and apolipoproteins in dyslipidemic schizophrenics receiving major tranquilizers

The subjects were 20 chronic schizophrenic patients with dyslipidemia (total cholesterol levels greater than or equal to 220 mg/dl, triglycerides greater than or equal to 150 mg/dl, or high-density lipoprotein cholesterol less than or equal to 40 mg/dl) who had been receiving neuroleptics for a mean of ten years. Each patient was given 100 mg of gamma-oryzanol three times daily for 16 weeks. Total cholesterol and low-density lipoprotein cholesterol levels, respectively, decreased significantly, from 204 and 124 mg/dl at baseline to 176 and 101 mg/dl at week 12. High-density lipoprotein cholesterol levels were 36.1 mg/dl at baseline and 35.9 mg/dl at week 12. Apolipoprotein (apo) B levels decreased significantly from 116 mg/dl to 101 mg/dl at week 16; apo A-II levels increased significantly from 31.7 mg/dl to 34.7 mg/dl; and the apo B/apo A-I ratio declined significantly from 0.99 to 0.84. No treatment side effects were recorded. It is concluded that gamma-oryzanol is safe and effective in the treatment of dyslipidemia.     

Atorvastatin and micronized fenofibrate alone and in combination in type 2 diabetes with combined hyperlipidemia

OBJECTIVE: This study evaluated the effect of a atorvastatin-fenofibrate combination on lipid profile, in comparison to each drug alone, in patients with type 2 diabetes and combined hyperlipidemia (CHL). RESEARCH DESIGN AND METHODS: A total of 120 consecutive patients, who were free of coronary artery disease (CAD) at entry, were studied for a period of 24 weeks. These patients were randomly assigned to atorvastatin (20 mg/day, n = 40), micronized fenofibrate (200 mg/day, n = 40), or a combination of both (atorvastatin 20 mg/day plus fenofibrate 200 mg/day, n = 40). The effect of treatment on LDL cholesterol, triglycerides (TGs), HDL cholesterol, apolipoprotein A-I and B, lipoprotein(a), and plasma fibrinogen (PF) was recorded. Moreover, the percentage of patients that reached the American Diabetes Association treatment goals and the estimated CAD risk status were calculated. RESULTS: No patient was withdrawn from the study because of side effects. The atorvastatin-fenofibrate combination reduced total cholesterol by 37%, LDL cholesterol by 46%, TGs by 50%, and PF by 20%, whereas it increased HDL cholesterol by 22% (P < 0.0001 for all). These changes were significantly better than those of both monotherapies. Of the patients on drug combination, 97.5% reached the LDL cholesterol treatment goal of <100 mg/dl, 100% reached the desirable TG levels of <200 mg/dl, and 60% reached the optimal HDL cholesterol levels of >45 mg/dl. These rates were significantly higher than those of both monotherapies. Combined treatment reduced the 10-year probability for myocardial infarction from 21.6 to 4.2%. CONCLUSIONS: The atorvastatin-fenofibrate combination has a highly beneficial effect on all lipid parameters and PF in patients with type 2 diabetes and CHL. It improved patients' CAD risk status significantly more than each drug alone.     

Regulation of the production and catabolism of plasma low density lipoproteins in hypertriglyceridemic subjects. Effect of weight loss.

In subjects with hypertriglyceridemia, plasma concentrations of low density lipoprotein (LDL) cholesterol are often normal or reduced. Perturbations that alter plasma very low density lipoprotein (VLDL) concentrations are associated with opposite changes in plasma LDL levels. To determine the mechanisms regulating plasma LDL levels, we used 131I-VLDL and 125I-LDL to measure the fractional catabolic rates (FCR), production rates (PR), and rates of interconversion of apoprotein B (apo B) in VLDL, intermediate density lipoprotein, and LDL in six hypertriglyceridemic subjects pre- and post-weight reduction. [2-3H]glycerol was used to quantitate VLDL triglyceride PR. All data are presented as mean +/- SD. Percent ideal body weight fell from 132 +/- 17.9 to 119 +/- 15.9% in the group, P less than 0.05. After weight loss, plasma VLDL triglyceride (486.0 +/- 364.1 vs. 191.3 +/- 65.4 mg/dl, P less than 0.05) and VLDL apo B (32.2 +/- 12.0 vs. 14.8 +/- 6.8 mg/dl, P less than 0.05) concentrations were reduced. VLDL triglyceride PR also fell after weight reduction (56.6 +/- 39.0 vs. 28.6 +/- 23.1 mg/kg per h, P less than 0.05), as did VLDL apo B PR (47.9 +/- 41.4 vs. 19.0 +/- 14.1 mg/kg per d, P less than 0.05). Pre-weight loss, plasma LDL cholesterol and apo B levels were low-normal or reduced (64.0 +/- 12.6 and 58.4 +/- 11.9 mg/dl, respectively) despite normal or elevated LDL apo B PR (17.4 +/- 7.2 mg/kg per d). The reduced cholesterol and apo B levels were associated with increased FCRs (0.68 +/- 0.29 d-1) and reduced cholesterol/protein ratios (1.01 +/- 0.18) in LDL. The plasma levels of LDL cholesterol and apo B rose after weight reduction (84.8 +/- 24.9, P less than 0.05; and 69.5 +/- 14.3 mg/dl, P less than 0.05, respectively, vs. base line). These increased concentrations resulted from a combination of events. First, the FCR for LDL apo B fell in five of six subjects with a significant reduction for the group as a whole (0.48 +/- 0.11 d-1, P less than 0.05 vs. base line). Second, the cholesterol/protein ratio increased in all six subjects with a significantly greater mean after weight loss (1.25 +/- 0.27, P less than 0.05 vs. base line). In contrast, the LDL apo B PR fell or was essentially unchanged in the six subjects after weight loss (mean, 14.4 +/- 2.8 mg/kg per d; NS vs. pre-weight loss). The changes in LDL catabolism and composition were associated with changes in the source of LDL apo B. Pre-weight loss, 73.3% of LDL was derived from VLDL, while 26.7% was directly secreted into plasma. Post-weight reduction, VLDL-derived LDL fell to 46.8% of total, while direct secretion accounted for 53.2% of LDL production. These changes were significant; P < 0.95. Thus, all subjects had direct secretion of LDL apo B and the magnitude of this source of VLDL triglyceride secretion. These results indicate that the regulation of plasma LDL levels in hypertriglyceridemic subjects is quite complex and that the rise in LDL levels after weight loss results from reduction in the fractional catabolism of this lipoprotein. The fall in the FCR is associated with changes in the source of LDL and in its composition.     

HDL and clinical and biochemical correlates in Italian non-smoker women.

High-density lipoprotein (HDL)-cholesterol levels, inversely related to the risk of myocardial infarction, are determined by genetic and environmental factors. The aim of this study was to evaluate the prevalence of low and high HDL plasma levels and the influence of environmental factors and lipid profile in an Italian non-smoker female population. HDL, apolipoprotein A-I, apolipoproteins, lipids and estrogen plasma levels were measured in a population of 1471 women with a mean age of 45 +/- 14 years. HDL values < or = 35 mg/dl were noted in 11.2% of the subjects, showing 2.4% coronary heart disease (CHD) prevalence. The 90th percentile was characterized by HDL levels > or = 66 mg/dl and the absence of coronary atherosclerosis. Total cholesterol, apolipoprotein B and triglycerides (r = -0.31, p < 0.0001) were the main determinants of HDL levels; apolipoprotein E, estrogen use, body mass index (BMI), alcohol consumption and age showed a weaker correlation. Apolipoprotein A-I concentration was influenced more notably by estrogen use, total cholesterol and apolipoprotein E; levels of triglycerides, apolipoprotein B, BMI, age and alcohol consumption are less important. The parameters considered here, taken together, explain HDL and apolipoprotein A-I variability of approximately 31% and 24%, respectively. A surprisingly high prevalence of very low (< or = 35 mg/dl) and high (> or = 66 mg/dl) HDL levels in Italian women further confirms the importance of studies on the HDL distribution in different population groups.     

Comparison of ultracentrifugation and a precipitation method for high-density lipoprotein cholesterol quantitation in insulin-dependent diabetic patients

We compared sodium phosphotungstic acid and magnesium chloride precipitation method for high-density lipoprotein (HDL) cholesterol quantitation with the ultracentrifugation method in 64 insulin-dependent diabetic patients with plasma triglyceride less than 3 mmol/l. The cholesterol content of HDL after precipitation of very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) was 86% +/- 3% of the cholesterol content of HDL (q greater than 1.063) determined after ultracentrifugation at q = 1.063 (1.33 +/- 0.05 mmol/l vs 1.55 +/- 0.06 mmol/l; p less than 0.001). HDL cholesterol determined after precipitation closely correlated to HDL cholesterol determined after ultracentrifugation (r = 0.97; p less than 0.001). The absolute difference between the HDL cholesterol values obtained by the two methods was correlated to HDL cholesterol (ultracentrifugation) (r = 0.75; p less than 0.001), but it was not correlated to VLDL cholesterol, LDL cholesterol, triglyceride, HbA1c, blood glucose or serum albumin. LDL cholesterol calculated by use of Friedewald's formula was 108% +/- 4% of the cholesterol content of LDL (q = 1.019 to 1.063), determined after ultracentrifugation, but the calculated and the ultracentrifugally determined LDL cholesterol values were closely correlated (r = 0.98; p less than 0.001). These results suggest that during sodium phosphotungstic acid and magnesium chloride precipitation of plasma from diabetic patients, a constant fraction of HDL cholesterol is co-precipitated, resulting in a systematic difference in HDL cholesterol quantitation when compared with the ultracentrifugation method.     

Efficacy and tolerability of lovastatin in elderly hypercholesterolemic patients.

In a previously published multicenter study (Kannel and associates, 1990), the effects of six months' treatment with lovastatin were evaluated in patients with hypercholesterolemia. In the present report the results from the 144 elderly patients (aged 65 to 83 years) are presented and compared with those from the 343 patients aged less than 65 years. The initial dose of lovastatin was 20 mg daily and could be increased to a maximum of 80 mg/day. After one month of treatment, in both the elderly and younger patients, levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, very-low-density lipoprotein cholesterol, and triglycerides, and the total cholesterol: high-density lipoprotein (HDL) cholesterol and LDL:HDL [corrected] cholesterol ratios were significantly lower and high-density lipoprotein cholesterol levels were significantly higher. These improvements in the lipid profile were maintained for six months in both patient groups. LDL cholesterol goals of less than 130 mg/dl in patients with coronary heart disease (CHD) or two CHD risk factors and less than 160 mg/dl among the other patients were achieved by 53% of the elderly patients and 40% of the younger patients at one month (P less than 0.01) and by 62% and 47% at six months (P less than 0.01). By the end of the study, the mean daily dose of lovastatin was 35.4 mg for the elderly and 38.4 mg for the younger patients. The drug was generally well tolerated by all patients. The results indicate that both elderly and younger hypercholesterolemic patients respond well to treatment with lovastatin.     

Effects of dietary cholesterol and fatty acids on plasma lipoproteins.

The effects of dietary cholesterol and fatty acids on low density and high density lipoproteins (LDL and HDL) were studied in 20 young men. After 2-3 wk of evaluations on ad lib. diets, basal diets, which consisted of 15% protein, 45% carbohydrates, 40% fat, and 300 mg/day of cholesterol, were given for 4-5 wk (Basal). The ratio of dietary polyunsaturated to saturated fatty acids (P/S) for different groups of subjects were 0.25, 0.4, 0.8, or 2.5. 750 and 1,500 mg/d of cholesterol were added to the basal diets as 3 and 6 eggs, respectively. Total cholesterol and LDL cholesterol were lower in all subjects on the basal diets than on the ad lib. diets. Addition of 750 mg cholesterol to the diet with P/S = 0.25-0.4 raised LDL cholesterol by 16 +/- 14 mg/dl to 115% of basal diet values (n = 11, P less than 0.01); 1,500 mg increased LDL cholesterol by 25 +/- 19 mg/dl to 125% (n = 9, P less than 0.01). On the diet with P/S = 0.8, 750 mg produced insignificant increases in LDL cholesterol, but 1,500 mg produced increases of 17 +/- 22 mg/dl to 115% of basal (n = 6, P less than 0.02). On the P/S = 2.5 diet, neither 750 nor 1,500 mg produced significant changes. Thus, both the cholesterol contents and P/S ratios of diets were important in determining LDL levels. The lipid and apoprotein compositions, flotation rates, molecular weights, and binding by cellular receptors of LDL were virtually unchanged by the addition of cholesterol to the diets high in saturated fat. These diets, therefore, caused an increase in the number of LDL particles of virtually unchanged physical and biological properties. On the diet with low P/S ratio, HDL2 rose, whereas this effect was absent on diets with high P/S ratios. The response of LDL to dietary manipulations is consonant with epidemiologic data relating diets high in cholesterol and saturated fat to atherogenesis. The response of HDL2, however, is opposite to that of its putative role as a negative risk factor. Further work is needed to clarify this interesting paradox.     

Estimating low-density lipoprotein cholesterol by the Friedewald equation is adequate for classifying patients on the basis of nationally recommended cutpoints

We compared low-density lipoprotein cholesterol (LDL) values obtained by the Friedewald formula--i.e., total cholesterol minus high-density lipoprotein (HDL) cholesterol minus very-low-density lipoprotein (VLDL) cholesterol (estimated as triglyceride divided by 5)--with those obtained by lipoprotein fractionation, using 4736 specimens. When triglycerides were less than 2.0 g/L, greater than 90% of estimated LDL cholesterol values were acceptable, within +/- 10% of measured values. At triglyceride concentrations of 2.0-4.0 g/L and 4.0-6.0 g/L, only 72% and 39%, respectively, of the estimates were acceptable. LDL values derived from an alternative formula, estimating VLDL as triglycerides divided by 6, were even less accurate. Nevertheless, the use of estimated LDL for risk classification based on the National Cholesterol Education Program Adult Treatment Panel cutpoints of 1.30 and 1.60 g/L was considered acceptable. At triglyceride concentrations less than or equal to 5.0 g/L, 88% of classifications based on estimated LDL (using triglycerides divided by 5) were concordant with those by measured LDL. Eleven percent of classifications were shifted across one cutpoint, evenly distributed between high and low. Fewer than 1% of classifications, all with Type III hyperlipoproteinemia, were misclassified two cutpoints high. Refinements in the estimation model did not substantially improve LDL estimation or concordance of risk classification.