Effects of ezetimibe/simvastatin on lipoprotein subfractions in patients with primary hypercholesterolemia: an exploratory analysis of archived samples using two commercially available techniques

BACKGROUND: Cholesterol-rich lipoproteins, including low-density lipoprotein cholesterol (LDL-C), intermediate-density lipoprotein cholesterol (IDL-C), and very-low-density lipoprotein cholesterol (VLDL-C), are known to promote atherosclerosis. Ezetimibe/simvastatin (E/S) is an efficacious lipid-lowering treatment that inhibits both the intestinal absorption and biosynthesis of cholesterol. OBJECTIVE: The aim of the current analysis was to compare the effects of ezetimibe and simvastatin monotherapy and E/S treatment on lipoprotein subfractions and LDL particle size in patients with primary hypercholesterolemia. METHODS: This was an exploratory (hypothesis generating) analysis of archived plasma samples drawn from patients in a multicenter, randomized, double-blind, placebo-controlled, parallel-arm study. After a washout and diet/placebo run-in, patients with hypercholesterolemia (LDL-C, > or =145- < or =250 mg/dL; triglycerides, < or =350 mg/dL) were randomized equally to 1 of 10 daily treatments for 12 weeks: E/S (10/10, 10/20, 10/40, or 10/80 mg), simvastatin monotherapy (10, 20, 40, or 80 mg), ezetimibe monotherapy (10 mg), or placebo. A subset of patients had lipid subfraction measurements taken at baseline (week 0) and postrandomization (week 12). Plasma samples were used to quantify cholesterol associated with VLDL subfractions (VLDLI+2 and VLDL3), IDL, and 4 LDL subfractions (LDL1-4) via the Vertical Auto Profile II method. LDL-C particle size was determined using segmented gradient gel electrophoresis. The primary end point was median percent change in subfraction cholesterol for E/S versus ezetimibe or simvastatin monotherapy, pooled across doses. RESULTS: Of the 1528 patients randomized in the original study, 1397 (91%) had lipid subfraction measurements taken. E/S was associated with significant reductions in VLDL-CI+2, VLDL-C3, IDL-C, LDL-C1, LDL-C2, and LDL-C3 versus ezetimibe, simvastatin, and placebo. E/S resulted in near-additive reductions in VLDL-CI+2, VLDL-C3, IDL-C, LDL-C1, LDL-C2, and LDL-C3 versus ezetimibe and simvastatin monotherapy. Of the subfractions examined, with regard to E/S, the greatest reductions were observed in IDL-C and LDL-C1, LDL-C2, and LDL-C3. When compared with placebo, ezetimibe, simvastatin, and E/S did not shift the distribution of LDL particles toward a larger, more buoyant LDL subclass pattern. CONCLUSION: E/S was more effective than ezetimibe and simvastatin monotherapy in reducing atherogenic lipoprotein subfractions in these patients with primary hypercholesterolemia.     

Estimation of VLDL cholesterol in hyperlipidemia

Lipoprotein data from 10947 fasting blood samples drawn between 1968 and 1982 in the Molecular Disease Branch at the National Institutes of Health were used to test the generalizability of estimating very low density lipoprotein cholesterol (VLDL-C) from plasma triglyceride (TG). Patient samples with total cholesterol levels over 500 mg/l and triglyceride values in the 0-100 000 mg/1 range were included in this study. A previously defined linear relationship VLDL-C = 0.20 (TG) was observed in the past by Friedewald and collaborators, allowing estimation of low density lipoprotein cholesterol (LDL-C) without ultracentrifugation for TG values up to 4 000 mg/1. The results from this report extend the use of the Friedewald relationship to higher TG levels, and to various dyslipidemic states. As the VLDL-C estimates become increasingly imprecise for TG values greater than 10 000 mg/l, caution should be exercised using the estimate in the higher TG ranges. Comparisons with an alternative equation VLDL-C = 0.166 (TG) showed equal or improved accuracy with this estimation procedure, particularly at high TG levels.     

Effects of pindolol on serum lipids, apolipoproteins, and lipoproteins in patients with mild to moderate essential hypertension

The effects of 12 weeks' administration of the beta-blocker pindolol (5 mg twice daily) on serum lipids, apolipoproteins (apo), and lipoproteins were studied in 20 normolipidemic patients with mild to moderate essential hypertension (WHO I-II). Pindolol significantly increased both high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), while very-low-density lipoprotein cholesterol (VLDL-C) was significantly decreased. Apo A-II levels were increased significantly and the apo B/apo A-I ratio, which is one of the atherogenic indexes, was decreased significantly after pindolol therapy. Total cholesterol, HDL subfraction cholesterols, the LDL-C/HDL-C ratio, triglycerides, apo A-I, apo B, apo C-II, apo C-III, and apo E did not change significantly.     

The association between lipid profiles and breast cancer among Taiwanese women.

BACKGROUND: Breast cancer incidence increased seven-fold from 1979 to 2002, and it has become the second most common cancer in Taiwanese women. Although the relationship between high-density lipoprotein cholesterol (HDL-C) and breast cancer has been studied, no consistent association has been explicitly confirmed. The aim of this study was to demonstrate the relationship between breast cancer and lipid profiles in Taiwanese women. METHODS: A total of 150 breast cancer patients before treatment and 71 healthy controls were enrolled. Lipid profiles in fasting serum were measured after participants gave their consent. RESULTS: The breast cancer patients had significantly lower values for HDL-C and apolipoprotein A-I (apoA-I), lower apoA-I/apoB ratios and higher values for very-low-density lipoprotein cholesterol (VLDL-C) than controls. After logistic regression analysis, the breast cancer patients had significantly higher values for VLDL-C and lower values for apoA-I after controlling for HDL-C and the apoA-I/apoB ratio. CONCLUSIONS: Our findings demonstrate that higher VLDL-C and lower apoA-I values were significantly associated with breast cancer, with a greater association between apoA-I values and the development of breast cancer than for HDL-C values.     

Role of lipids, lipoproteins and vitamins in women with breast cancer

OBJECTIVES: Improper balance between the production of reactive oxygen metabolites (ROMs), and antioxidative defense system have been defined as oxidative stress in various pathologic conditions. Lipids, lipoproteins and antioxidative vitamins have been associated with the risk of breast cancer. The present case-control study was conducted to investigate the status of antioxidative vitamins (A, C and E), lipids (total cholesterol; TC and triglycerides; TG), lipoproteins (high-density lipoprotein cholesterol; HDL-C and low-density lipoprotein cholesterol; LDL-C) and retinol-binding protein (RBP) in breast cancer patients. The aim of the study was to find out oxidative stress in breast cancer. DESIGN AND METHODS: Plasma lipids, lipoproteins and vitamins were estimated in 54 untreated breast cancer patients of different clinical stages and in 42 age- and sex-matched controls. RESULTS: Plasma TC (p < 0.05), and LDL-C and TG (p < 0.01) were found to be significantly elevated among breast cancer patients as compared to the controls. On the other hand, plasma HDL-C concentration (p < 0.001) and vitamin C and E (p < 0.01) were observed significantly decreased in breast cancer patients than in the controls. The maximum changes in plasma TC, and vitamin C and E concentrations were observed in breast cancer patients with stage IV when compared with controls. CONCLUSION: The study suggests that higher levels of TC and TG may play important role in carcinogenesis. Furthermore, the elevated plasma LDL-C concentration, which is more susceptible to oxidation, may result in higher lipid peroxidation in breast cancer patients. However, decreased concentrations of HDL-C and vitamin C and E are not likely to be sufficient enough to counter higher ROMs production reported earlier in breast cancer patients that may cause oxidative stress leading to cellular and molecular damage thereby resulting in cell proliferation and malignant conversions.     

Effect of Pravastatin in the Treatment of Patients with Type III Hyperlipoproteinemia

OBJECTIVE: To determine the efficacy and safety of pravastatin in the treatment of subjects with Type III hyperlipoproteinemia. DESIGN: Randomized, double-blind, placebo-controlled, crossover study. SETTING: Four lipid research clinics in the United States. PATIENTS: Twenty subjects between 18 and 70 years old with three diagnostic features of Type III hyperlipoproteinemia: very-low-density lipoprotein cholesterol (VLDL-C)/total plasma triglyceride ratio in excess of 0.30; beta-migrating VLDL pattern on agarose-gel electrophoresis; and the homozygous apolipoprotein E phenotype E(2)/E(2). After 4 weeks of dietary control, the subjects were eligible if their mean plasma total cholesterol level was at least 250 mg/dl and mean plasma trigylceraide level was at least 220 mg/dL. INTERVENTIONS: Subjects were randomly assigned to pravastatin 40 mg hs or placebo hs at the start of the first 6-week double-blind treatment period. After completing this phase, subjects entered a 4-week placebo/drug washout phase before crossing over to the opposite treatment for the second 6-week double-blind treatment period. MEASUREMENTS: Plasma VLDL-C and low density lipoprotein cholesterol (LDL-C) after ultracentrifugation and total triglyceride, cholesterol and high-density lipoprotein cholesterol (HDL-C) after 6 weeks of treatment; adverse clinical events and abnormal laboratory results. RESULTS: After 6 weeks of pravastatin theraphy, plasma levels of VLDL-C and LDL-C decreased 49% and 39%, respectively (p less-than-or-equal 0.01 vs. placebo). Total cholesterol and triglyceride concentrations decreased 36% and 22%, respectively (p less-than-or-equal 0.001 vs. placebo). Levels of HDL-C increased 8% (p less-than-or-equal 0.01 vs. placebo). Pravastatin was tolerated well. One marked laboratory abnormality, an asymptomatic elevation of creatine phosphokinase, resolved upon completing pravastatin treatment. CONCLUSIONS: Pravastatin lowers plasma VLDL-C, LDL-C, total cholesterol, and triglyceride and raises HDL-C in subjects with Type III hyperlipoproteinemia. The safety profile is excellent. Pravastatin reductase inhibitor therapy affords a useful approach to the management of Type III or remnant removal disease.     

Plasma levels of coenzyme Q(10), vitamin E and lipids in uremic patients on conservative therapy and hemodialysis treatment: some possible biochemical and clinical implications

Coenzyme Q(10) (CoQ(10)), vitamin E, total cholesterol, HDL-cholesterol (HDLC) and triglycerides were measured in the plasma of 62 patients with kidney failure, 46 under hemodialysis treatment and 16 under conservative therapy, and 95 controls. The sum of LDL-cholesterol (LDL-C) and VLDL-cholesterol (VLDL-C) was also calculated for each patient. The ratio CoQ(10)/LDL-C+VLDL-C in both conservative therapy and hemodialysis populations was significantly lower (P<0.001) compared with normal controls and remained unchanged after the dialysis treatment. On the contrary the ratio vitamin E/LDL-C+VLDL-C was normal but decreased significantly (P<0.02) after each dialysis. Since coenzyme Q is the main inhibitor of the prooxidant action of vitamin E, it was hypothesized that its decrease in both the populations examined could make the lipoproteins of these patients more vulnerable to a peroxidative attack.     

Niacin as a component of combination therapy for dyslipidemia

Dyslipidemia is one of the most important modifiable risk factors for coronary disease. Despite the availability of highly effective lipid-modifying agents, many patients still do not reach lipid targets established by national guidelines. Niacin has been known to be an effective treatment of dyslipidemia for almost half a century. Niacin substantially increases high-density lipoprotein cholesterol (HDL-C) levels while lowering levels of low-density lipoprotein cholesterol (LDL-C), triglycerides, and lipoprotein(a). In addition, niacin converts small LDL particles into more buoyant, less atherogenic LDL particles. Combined with other agents, niacin offers an important treatment option for patients with dyslipidemia. In particular, niacin complements LDL-C-lowering drugs; it is the most effective agent available for increasing HDL-C levels while lowering levels of LDL-C and triglycerides and improving other lipid risk factors such as lipoprotein(a). Combining niacin with statins or bile acid sequestrant therapy is safe and effective for improving lipid levels and decreasing coronary risk. Differences in niacin formulations dictate tolerability profiles and should be considered when selecting niacin as part of lipid therapy. Furthermore, adverse effects on glucose and insulin sensitivity should be considered when selecting candidates for niacin therapy. Adding niacin to lipid-lowering regimens is a valuable option for physicians treating patients with dyslipidemia and should be considered in appropriate patients.     

Hemostatic effects of atorvastatin versus simvastatin

OBJECTIVE: To compare the effects of simvastatin and atorvastatin on hemostatic parameters. METHODS: Sixty-one patients with primary hypercholesterolemia without coronary heart disease were treated with atorvastatin 10-20 mg/d or simvastatin 10-20 mg/d. At baseline, 4, 12, and 24 weeks, lipid levels such as low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), very-low-density lipoprotein cholesterol (VLDL-C), triglycerides (TGs), and hemostatic parameters such as platelet counts, partial thromboplastin time (PTT) prothrombin time (PT), and fibrinogen levels were measured. RESULTS: At 12 weeks, the doses of the statins were increased to 20 mg/d in 10 of 35 (28.5%) patients treated with atorvastatin and 18 of 26 (69.2%) patients treated with simvastatin when the target level of LDL-C (130 mg/dL) was not reached. Mean doses were atorvastatin 12.8 mg/d and simvastatin 16.9 mg/d. After 24 weeks, 5 patients (14.3%) in the atorvastatin group and 4 patients (15.3%) in the simvastatin group had not reached the goal. In patients with diabetes, target level (LDL-C <100 mg/dL) was not reached in 35.7% of patients in the atorvastatin group and 44.4% of patients in the simvastatin group. Both simvastatin and atorvastatin were effective in lowering TC and LDL-C levels (p < 0.001). Atorvastatin lowered TGs significantly (p < 0.01). Neither atorvastatin nor simvastatin significantly reduced VLDL-C levels. HDL-C levels increased with atorvastatin, but there was no significant difference between the 2 groups. Platelet counts decreased with both statins nonsignificantly. Moreover, fibrinogen levels decreased with simvastatin and atorvastatin, but these reductions were significant only for simvastatin (p < 0.05). We detected prolongation of the PT with both drugs (p < 0.05); however, prolongation of the PTT was significant only with simvastatin (p < 0.001). Effectiveness of both statins on lipid and hemostatic parameters was dose related. Adverse effects were seen in 5 patients (14.2%) treated with atorvastatin and 3 patients (11.5%) treated with simvastatin. Elevations in serum transaminase levels >3 times the upper limit of normal and in creatine phosphokinase >5 times the upper limit of normal were not observed in any group. CONCLUSIONS: Atorvastatin was more effective than simvastatin on lipid parameters, although statistically insignificantly, while simvastatin produced more significant changes than atorvastatin on hemostatic parameters. The mean dose of simvastatin was greater than that of atorvastatin. Both statins had increased effects on lipid and hemostatic parameters when doses were increased. Atorvastatin and simvastatin were well tolerated. Different effects of statins on lipid levels and on coagulation parameters should be considered in patients with hypercholesterolemia and tendency to coagulation, especially in preventing thrombotic events. Further studies in larger trials are needed to confirm these observations.     

Lipoprotein cholesterol concentrations in the plasma of human subjects as measured in the fed and fasted states

Lipoprotein cholesterol concentrations in plasma are routinely estimated by using the Friedewald formula, whereby very-low-density lipoprotein cholesterol (VLDL-C) is estimated to be one-fifth the plasma triglyceride concentration. Ordinarily, this formula is applied only to plasma sampled from patients in the fasted state. To determine whether lipoprotein cholesterol measurements are altered substantially in plasma sampled from nonfasting subjects, we obtained postprandial blood samples from 22 healthy subjects (nine men, 13 women, ages 22-79 years) fed a fat-rich meal (1 g fat per kilogram body wt.). The plasma triglyceride concentration increased postprandially in all subjects (233 +/- 16% of baseline at 3 h). The mean cholesterol concentration in plasma was essentially unchanged. High-density lipoprotein cholesterol (HDL-C) was significantly decreased (94 +/- 2% at 3 h, P less than 0.001). VLDL-C and low-density lipoprotein cholesterol (LDL-C), estimated by the Friedewald formula, were compared with measurements obtained by modified Lipid Research Clinics (LRC) methodology. As measured by either method, VLDL-C increased and LDL-C decreased significantly after the fat-rich meal. These postprandial changes were significantly greater (P less than 0.01) when estimated by the Friedewald formula than by LRC methodology. We conclude that (a) lipoprotein cholesterol concentrations measured in the fed subject differ significantly from those measured in the fasted subject, and (b) plasma must be obtained after at least a 12-h fast if an individual's risk of coronary heart disease is to be accurately assessed.     

Validation of the Friedewald formula for the determination of low-density lipoprotein cholesterol compared with beta-quantification in a large population

Lipoprotein data from 9477 subjects, covering a wide range of total plasma cholesterol levels, were used to examine the validity of the Friedewald formula for estimating plasma concentrations of low-density lipoprotein cholesterol (LDL-C) using high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations. Values of LDL-C obtained from the Friedewald formula were compared with values of LDL-C derived from preparative ultracentrifugation used as a reference method. We found that the bias associated with the Friedewald formula was not related to plasma LDL-C levels and was smaller than −4.0% even for plasma LDL-C values <3.0 mmol/l. Moreover, in the subgroup of individuals with plasma TG levels ≤4.5 mmol/l, the Friedewald formula underestimated LDL-C levels with a bias between −3.1% and −1.9% according to TG quartiles. Interestingly, the Friedewald formula showed no significant bias in patients with plasma TG levels between 4.51 and 8.82 mmol/l, suggesting that the calculated LDL-C are reliable and could be clinically useful in patients with plasma TG levels higher than 4.5 mmol/l which is the reference cut-point value used by most clinical laboratories. Finally, multiple regression analyses showed that the very low-density lipoprotein cholesterol (VLDL-C)/TG ratio represented nearly 63% (P < 0.0001) of the variance of the bias associated with the Friedewald formula. We concluded that the Friedewald formula may be reliable at low LDL-C levels and at TG levels up to 9 mmol/l but may be used with caution when the VLDL-C/TG ratio is high as observed in patients with type III dysbetalipoproteinemia.     

Efficacy and Tolerability of Low-dose Simvastatin and Niacin, Alone and in Combination, in Patients With Combined Hyperlipidemia: A Prospective Trial

BACKGROUND: Combination lipid-lowering therapy may be desirable in patients with elevated low-density lipoprotein cholesterol, high triglycerides, and low high-density lipoprotein cholesterol. This study was conducted to determine the lipid-lowering efficacy of the combination of low-dose simvastatin and niacin in patients with combined hyperlipidemia and low high-density lipoprotein cholesterol. METHODS AND RESULTS: In this multicenter, prospective, randomized trial, 180 patients with hypercholesterolemia and hypertriglyceridemia and/or low high-density lipoprotein cholesterol were randomized to combination simvastatin (10 mg/day) and niacin (0.75 g/day) or to either drug alone for 9 weeks. The dose of niacin was doubled (from 0.75 g/day to 1.5 g/day) in both the combination and niacin arms for the remaining 8 weeks. The combination of simvastatin, 10 mg/day, and niacin, 1.5 g/day, reduced total, low-density lipoprotein, and very low-density lipoprotein cholesterol and triglycerides by 24%, 29%, 45%, and 31%, respectively, while increasing high-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol-lowering effect of simvastatin; however, the combination was more effective than either monotherapy at raising high-density lipoprotein cholesterol and lowering very low-density lipoprotein cholesterol (P <.05). More patients discontinued treatment because of an adverse event in the niacin (P <.03) and combination groups (P =.06) than the simvastatin group. CONCLUSIONS: Treatment of patients with combined hyperlipidemia and/or low high-density lipoprotein with combination low-dose simvastatin and niacin resulted in large reductions in total, low-density lipoprotein, and very low-density lipoprotein cholesterol and increases in HDL cholesterol. Although the combination was well tolerated in the current trial, its safety needs to be evaluated in larger trials of longer duration.     

An open-label comparison of the effects of simvastatin and niacin alone and combined on the lipid profile and lipoprotein (a) level in an Indian population with dyslipidemia

Abstract

Background:

Patients with dyslipidemia often require the use of >1 lipid-altering agent to achieve the target levels recommended by the National Cholesterol Education Program Adult Treatment Panel III.

Objective:

The aim of this study was to compare the effects of simvastatin and niacin alone and combined on the lipid profile and lipoprotein (a) (Lp[a]) level in an Indian population with dyslipidemia.

Methods:

This 12-week, open-label, nonrandomized study was conducted at the Departments of Pharmacology and Medicine, Government Medical College, Amritsar (Punjab), India. Patients aged 30 to 70 years with dyslipidemia were eligible. Patients were assigned to 1 of 3 treatment groups. Group 1 received simvastatin 20 mg/d for 12 weeks. Group 2 received niacin at doses of 375 mg/d for 1 week, 500 mg/d for 1 week, and 500 mg BID for 10 weeks. Group 3 received simvastatin 10 mg/d plus niacin (375 mg for 1 week and 500 mg for 11 weeks). The lipid profile (low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], total cholesterol [TC], and triglycerides [TG]) and Lp(a) were measured before the start of therapy and at 6 and 12 weeks of treatment. Percentage changes from baseline were calculated. Adverse effects (AEs) were recorded at weeks 6 and 12 and through spontaneous reporting.

Results:

Ninety patients were enrolled (50 men, 40 women; 30 patients per treatment group). In group 1, the mean (SD) percentage decrease in LDL-C level at 12 weeks was 42.79% (16.29%) (P < 0.05), but no significant change was seen in group 2 or 3. The mean (SD) percentage increases in HDL-C level were 18.43% (13.28%) and 20.82% (17.57%) in groups 2 and 3, respectively (both, P < 0.05), but no significant change was seen in group 1. TC levels decreased by a mean (SD) of 32.97% (13.66%) in group 1 (P < 0.05), but no significant change was seen in group 2 or 3. TG and Lp(a) levels did not change significantly in any of the 3 treatment groups. Flushing, myalgia, and dyspepsia were the most common AEs in patients receiving niacin.

Conclusions:

In this study in Indian patients with dyslipidemia, simvastatin-niacin combination therapy was associated with greater changes in lipid profile compared with either agent used alone. Niacin was also associated with greater changes in Lp(a) levels. AEs were less prevalent with combination therapy than with niacin alone.Key words: dyslipidemia, simvastatin, niacin, combination therapy     

Combination treatment with atorvastatin plus niacin provides effective control of complex dyslipidemias: a literature review

Patients with dyslipidemia receive a cardiovascular benefit from lowering low-density lipoprotein cholesterol (LDL-C). Atorvastatin is currently one of the most effective approved medications for lowering LDL-C, and has been shown to significantly reduce cardiovascular risk in many patient groups. However, even with substantial lowering of LDL-C with atorvastatin, patients still have a residual risk for coronary heart disease. Elevated triglyceride levels and low high-density lipoprotein cholesterol (HDL-C) levels may contribute to this risk. Approved medications targeting these secondary lipid parameters include fibrates, omega-3 fatty acids, and niacin. Among these medications, niacin provides the optimal increase in HDL-C levels and has efficacy similar to the other medications in lowering triglyceride levels. However, there are challenges to adherence with niacin treatment. The most common challenge during niacin treatment is flushing, although it typically decreases with ongoing use and can be ameliorated by pretreatment with aspirin and counseling by the prescriber. A combination of atorvastatin and niacin may provide more complete normalization of the lipid profile and increased cardiovascular benefits. A literature review of the PubMed and Embase databases was conducted for clinical studies that reported on the lipid-modifying efficacy of the atorvastatin plus niacin combination. Identified studies involved patients at risk for coronary heart disease and patients with established coronary heart disease. Overall, the studies were small but indicated that atorvastatin in combination with niacin was efficacious in normalizing lipid parameters. Larger lipid studies as well as studies evaluating cardiovascular outcomes during atorvastatin plus niacin treatment are warranted.     

Component analysis of HPLC profiles of unique lipoprotein subclass cholesterols for detection of coronary artery disease

BACKGROUND: Patients with coronary artery disease (CAD) are known to have several lipoprotein abnormalities. We examined plasma cholesterol concentrations of major lipoproteins and their subclasses, using a gel permeation HPLC, to establish an association between a lipoprotein subclass pattern and the presence of CAD. METHODS: We performed a simple and fully automated HPLC, followed by mathematical treatment on chromatograms, for measuring cholesterol concentrations of major lipoproteins and their subclasses in 62 male patients (45 with CAD and 17 controls without CAD) who underwent cardiac catheterization. RESULTS: For major lipoprotein classes, the patient group had a significantly (P<0.05) higher LDL-cholesterol (LDL-C) and lower HDL-cholesterol (HDL-C), but no difference in VLDL-cholesterol (VLDL-C) concentrations. For lipoprotein subclasses, the patient group had a significantly higher small VLDL-C (mean particle diameter of 31.3 nm, P<0.001), small LDL-C (23.0 nm, P<0.05), and very small LDL-C (16.7-20.7 nm, P<0.001), but a significantly lower large HDL-C (12.1 nm, P<0.001) concentrations. Combined variables of "small VLDL-C+small LDL-C+very small LDL-C-large HDL-C" differentiated the patient from the control group more clearly than single-subclass measurements or calculated traditional lipid markers. CONCLUSIONS: These results suggest the usefulness of multiple and simultaneous subclass analysis of proatherogenic and antiatherogenic lipoproteins and indicate that HPLC and its component analysis can be used for easy detection and evaluation of abnormal distribution of lipoprotein subclasses associated with CAD.     

Effect of lovastatin on serum lipids in patients with nonfamilial primary hypercholesterolemia

The effect of lovastatin on serum lipids and its tolerability in patients with non-familial primary hypercholesterolemia (type II-A and type II-B) during a six-month period were evaluated in this open-label study. Thirty-eight patients were enrolled in the study; tolerability was assessed in all 38 patients. Thirty patients completed the study, and the effect of lovastatin on serum lipids in these patients was assessed. Some patients had been treated for hypercholesterolemia with long-term dietary and other non-pharmacologic means before entry into the study. All patients were unresponsive to a six-week program of intensive dietary therapy and other nonpharmacologic treatment to lower their blood cholesterol levels before receiving lovastatin. While maintaining intensive dietary therapy, administration of lovastatin was instituted at a dosage of 20 mg/day, which was increased by 20-mg increments monthly, as necessary, to a maximum of 80 mg/day. In an effort to achieve goal levels of low-density lipoprotein cholesterol (LDL-C), ten patients received a daily dosage of 20 mg, 12 patients received 40 mg, seven patients 60 mg, and one patient 80 mg. Twenty-nine of the 30 patients achieved significant lowering of serum levels of total cholesterol (TC), LDL-C, and apolipoprotein (apo) B-I; this was demonstrated after the first month of therapy with lovastatin and was maintained throughout the six-month treatment period. One patient failed to demonstrate lowering of these serum lipids, despite receiving the maximum recommended dosage of lovastatin of 80 mg/day. Comparative measurements of serum lipids during dietary therapy alone and after six months of diet plus lovastatin therapy were as follows: TC, 289 +/- 5 versus 216 +/- 9 mg/dl (P less than 0.0005); LDL-C, 206 +/- 4 versus 141 +/- 5 mg/dl (P less than 0.0005); and apo B-I, 112 +/- 3 versus 89 +/- 2 mg/dl (P less than 0.0005). Serum levels of very-low-density lipoprotein cholesterol (VLDL-C) and triglycerides decreased slightly during lovastatin therapy, but the changes were not statistically significant. There were slight but statistically insignificant increases in serum levels of high-density lipoprotein cholesterol (HDL-C), apo A-I, and apo A-II.(ABSTRACT TRUNCATED AT 400 WORDS)     

Association between serum lipids and breast cancer risk in premenopausal women: systematic review and meta-analysis

ObjectiveAssociations between serum lipids and their individual components with premenopausal breast cancer risk are unclear. This meta-analysis summarized the literature on serum lipids and premenopausal breast cancer risk to elucidate their relationship.MethodsEligible studies were identified by searching the PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases until 31 December 2020. Standardized mean difference (SMD) scores with 95% confidence intervals (95%CIs) were used to assess the impact of serum lipids on premenopausal breast cancer risk. The I² statistic was calculated to measure the percentage of heterogeneity, and Egger’s test was performed to measure publication bias.ResultsThirteen studies were included. The SMD scores of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) were 12.90 (95%CI: 7.19–18.61) and 31.43 (95%CI: 8.72–54.15), respectively. The SMD scores of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were not significantly different between the groups. The included studies were highly heterogeneous. There were no publication biases found in TC, LDL-C, or HDL-C analyses, whereas publication bias was present in the TG analysis.ConclusionsTG and LDL-C were higher in premenopausal breast cancer patients than in women without breast cancer. However, no significant differences were found in TC or HDL-C levels.     

血清脂质、脂蛋白胆固醇和载脂蛋白在冠心病中的临床意义

目的研究冠心病患者的血清脂质、脂蛋白胆固醇和载脂蛋白的变化、辨别力和诊断价值。方法测定64例冠心病(CHD)患者和60例正常人的血脂、脂蛋白胆固醇和载脂蛋白,并比较计算其辨别力和诊断价值。结果和结论冠心病患者的TC(女)、TG、LDL-C、ApoB、LDL-C/HDL-C和ApoB/ApoAI明显高于正常人(P<0.05),HDL2-C、HDL3-C、HDL-C、ApoAI和HDL-C/TC明显低于正常人(P<0.05)。由HDL-C、TC和TG血脂三项可代替HDL-C、LDL-C、VLDL-C、TC和TG血脂五项,对冠心病的诊断目前有应用价值,若加上HDL2-C和HDL3-C或ApoAI和ApoB,则对冠心病的诊断更有意义。     

Statins for treatment of dyslipidemia in chronic kidney disease.

Dyslipidemia is a potent cardiovascular (CV) risk factor in the general population. Elevated low-density lipoprotein cholesterol (LDL-C) and/or low high-density lipoprotein (HDL-C) are well-established CV risk factors, but more precise determinants of risk include increased apoprotein B (ApoB), lipoprotein(a) [Lp(a)], intermediate and very low-density lipoprotein (IDL-C, VLDL-C; "remnant particles"), and small dense LDL particles. Lipoprotein metabolism is altered in association with declining glomerular filtration rate such that patients with non dialysis-dependent chronic kidney disease (CKD) have lower levels of HDL-C, higher triglyceride, ApoB, remnant IDL-C, remnant VLDL-C, and Lp(a), and a greater proportion of oxidized LDL-C. Similar abnormalities are prevalent in hemodialysis (HD) patients, who often manifest proatherogenic changes in LDL-C in the absence of increased levels. Patients treated with peritoneal dialysis (PD) have a similar but more severe dyslipidemia compared to HD patients due to stimulation of hepatic lipoprotein synthesis by glucose absorption from dialysate, increased insulin levels, and selective protein loss in the dialysate analogous to the nephrotic syndrome. In the dialysis-dependent CKD population, total cholesterol is directly associated with increased mortality after controlling for the presence of malnutrition-inflammation. Treatment with statins reduces CV mortality in the general population by approximately one third, irrespective of baseline LDL-C or prior CV events. Statins have similar, if not greater, efficacy in altering the lipid profile in patients with dialysis-dependent CKD (HD and PD) compared to those with normal renal function, and are well tolerated in CKD patients at moderate doses (相似文献