Abstract
Background
Significantly higher cytotoxic and thrombogenic human electronegative low-density lipoprotein (LDL), or L5, has been found in patients with stable coronary artery disease and acute coronary syndrome. We hypothesized that the statin-benefit groups (SBGs) defined by the new cholesterol guideline were of higher electronegative L5.
Methods
In total, 62 hyperlipidemia patients (mean age 59.4 ± 10.5, M/F 40/22) were retrospectively divided into SBGs (n = 44) and N-SBGs (n = 18). The levels of complete basic lipid panel, biochemical profile and electronegative L5 of each individual were obtained before and after rosuvastatin 10 mg/day for 3 months.
Results
After 3 months’ statin therapy, significant reduction of total cholesterol, LDL-C and triglyceride were demonstrated (all p-values < 0.05), with 38.4% LDL-C reduction. The percentage of L5 was significantly reduced by 40.9% (from 4.4% to 2.6%) after statin therapy (p = 0.001). Regarding absolute L5 concentration, derived from L5% multiplied by LDL-C, there was approximate 63.8% reduction (from 6.3 mg/dL to 2.3 mg/dL) of absolute L5 (p < 0.001) after statin treatment. Notably, while plasma LDL-C levels were similar between SBGs and N-SBGs (152.8 ± 48.6 vs. 146.9 ± 35.0 mg/dL), the SBGs had significantly elevated L5% (5.2 ± 7.4% vs. 2.6 ± 1.9%, p = 0.031) and higher absolute L5 concentration (7.4 ± 10.4 vs. 3.7 ± 3.1 mg/dL, p = 0.036). Linear regression showed the significantly positive correlation between the plasma L5 concentration and the 10-year cardiovascular risk by pooled cohort equation (r = 0.297, p < 0.05).
Conclusions
The four SBGs defined by the 2013 ACC/AHA new cholesterol guideline tend to have increased atherogenic electronegative L5. Statin therapy can effectively reduce the electronegative L5 of these four major SBGs.
Keywords: Cardiovascular risks, Cholesterol guideline, Electronegative LDL, Statin
INTRODUCTION
Statin therapy has been recommended as the main approach for lowering low-density lipoprotein cholesterol (LDL-C) in both primary and secondary prevention for cardiovascular diseases.1-6 Large-scale, randomized clinical trials of statin therapy have proven that the lower the LDL-C, the better the clinical cardiovascular outcomes.7,8 Though the safe threshold of LDL-C levels has not been reliably confirmed, the recent IMPROVE-IT trial indicated that LDL-C can be reduced to 53.2 mg/dL by ezetamibe added onto simvastatin therapy with reduced stroke and heart attacks experienced by patients with acute coronary syndrome after 7-years follow up.9,10 Other than ezetamibe, both fenofibrate and niacin had been reported to have failed to obtain the positive impacts on hard outcomes in patients with dyslipidemia during their representative clinical trials when added on statin.11,12 While the efforts of aggressive lipid lowering remain, new cholesterol guidelines published in 2013 by AHA/ACC in Dallas at first advocated that statin should be prescribed for four statin-benefit groups regardless of their initial LDL-C levels.13 Statin therapy should be aimed to reduce the risk, but not merely the LDL goal of those patients vulnerable to have higher cardiovascular events. The critiques suggested that the LDL target should be pursued instead of “statinized the planet”, while some experts favored this approach and found it is easier for the education of both patients and physicians.14,15
The success of statin therapy for cardiovascular disease management not only came from LDL-lowering, but also from its pleiotropic effects.16,17 Statin can stabilize the vulnerable plaque, and in some reports with high-intensity statin therapy, a slight regression of atherosclerotic plaques can be achieved by coronary intravascular ultrasound study.18,19 However, statin-induced adverse effects, i.e., muscle damage, liver function impairment and new-onset diabetes, might be confronted by patients with high susceptibility.20-22 To select the appropriate candidates for statin therapy, the new AHA/ACC guideline offers better evidence-based practice for clinical physicians to follow.23
In the underlying science, oxidized LDL was previously known to be toxic to endothelial wall and uptake by macrophages as foam cells.24,25 However, most of the experimental oxidized low-density lipoprotein (Ox-LDL) studies were conducted by artificially ox-LDL particles on bench work.26 In recent years, some modified LDL has emerged as lipid markers for evaluating lipid toxicity in atherosclerosis.27 For example, using size-exclusion column technique, small-dense LDL-C is predominantly found in diabetic dyslipidemia patients, while large-buyout LDL-C is normally found in healthy subjects.28 Recently, electronegative LDL by capillary electrophoresis, or by ion-exchange column coupled with fast protein liquid chromatography (FPLC) analysis in the laboratory, can be isolated from human plasma and has been repeatedly approved to be much more atherogenic.29,30
In the study, we aimed to analyze the levels of electronegative LDL isolated from human plasma in patients with hyperlipidemia, and to distinguish the differences between the electronegative LDL levels in patients from four major statin benefit groups (SBG) defined by AHA/ACC new cholesterol guidelines 2013 from the non-statin benefit groups (N-SBG),13 and finally investigate the therapeutic effects of statin (rosuvastatin 10 mg/day) of 3 months on electronegative LDL in SBG versus N-SBG. We hypothesized that these four SBGs were characterized by a higher level of electronegative L5, which makes them suitable candidates to achieve benefit from statin therapy.
METHODS AND MATERIALS
Study subjects
This study was approved by the institutional review boards of Kaohsiung Medical University Hospital (KMUH) and Kaohsiung Municipal Ta-Tung Hospital (KMTTH). All participants were enrolled and gave written informed consent in accordance with the Declaration of Helsinki between October 2010 and August 2014. By examining the medical history and clinical profiles, a cohort of 62 asymptomatic patients with dyslipidemia without prior statin use was divided into the SBG (n = 44) and N-SBG (n = 18) groups. According to the ACC/AHA 2013 new cholesterol guideline, patients who met the following criteria were considered to be the SBGs: 1) clinical atherosclerotic cardiovascular disease (ASCVD), including cerebrovascular disease, coronary artery disease and/or peripheral arterial disease; 2) type 2 diabetes; (3) primary hypercholesterolemia with LDL-C > 190 mg/dL; and finally, 4) calculated 10-year cardiovascular diseases > 7.5% by pooled cohort equation developed and defined in ACC/AHA new cholesterol guideline. Clinical and medication histories for the 3 months before case enrollment were recorded for each patient. Lipid parameters, including total cholesterol, triglyceride, LDL-C, high-density lipoprotein cholesterol (HDL-C), apo-B, apo-A and high-sensitivity C-reactive protein (hs-CRP) for all study subjects were measured in the Department of Laboratory Medicine at KMUH (accredited by the College of American Pathologists) according to standard operating procedures.
LDL isolation and separation of LDL subfractions
Whole blood samples (20 mL) were freshly collected and anticoagulated with 5 mM ethylenediaminetetraacetic acid (EDTA). LDL (density 5 1.063-1.019) was isolated by sequential potassium bromide density centrifugation and treated with 5 mM EDTA and nitrogen to avoid ex vivo oxidation. LDL was further divided into subfractions L1, L2, L3, L4, and L5 against a graded salt gradient by using anion exchange columns (Uno-Q12; Bio-Rad Laboratories, Inc., Hercules, CA, USA) with the AKTA FPLC (GE Healthcare Life Sciences, Pittsburgh, PA, USA) as previously described. The effluent was monitored at 280 nm and protected from ex vivo oxidation with 5 mM EDTA. The LDL subfractions from patients with STEMI were separately concentrated by using Centriprep Centrifugal Filters (YM-30; EMD Millipore Corp., Billerica, MA, USA) and sterilized by passing through 0.22-mm filters.
Other atherogenic markers and hs-CRP
The detection of apo-B, apo-AI, and hs-CRP were done by the central laboratory in Kaohsiung Medical University hospital and Kaohsiung Municipal Ta-Tung hospital. The absolute levels of apo-B and apo-AI, as well as the ratio of apo-B/apo-AI, served as the atherogenic markers in this study.
Statistic analysis
All data was presented as mean ± standard deviation (SD) or n (%). Baseline characteristics were compared between statin-benefit versus statin non-benefit groups with the Student’s t-test for continuous variables, and Pearson’s chi-square test or Fisher’s exact test was utilized for categorical variables. Linear correlation was conducted for the 10-year cardiovascular risks versus electronegative LDL levels. A p value < 0.05 was considered to be statistically significant. Statistical analysis was performed using SPSS software version 16.0 (SPSS Inc. Chicago, IL, USA).
RESULTS
The mean age of the study patients was 59.4 ± 10.5 years old, and about two-thirds were male. The prevalence of dyslipidemia and hypertension of the study patients by their past medical history were 100% and 67/7%, respectively. Baseline characteristics of a total of 62 patients are summarized in Table 1. Approximately 16.1 % patients are diabetic and 30.6% patients are current cigarette smokers. The average lipid profile was also listed in Table 1, including total cholesterol (T-chol) of these patients of 236.8 ± 37.8 mg/dL, triglyceride was 186.8 ± 171.2 mg/dL, HDL-C was 53.5 ± 17.3 mg/dL, and LDL-C content was 148.6 ± 39.1 mg/dL. Finally, the L5% was 4.4 ± 6.4 and the absolute concentration of plasma L5 was 6.3 ± 9.0 mg/dL. The representative FPLC analysis patterns from a patient with coronary artery disease and for a normal subject were illustrated in Figure 1(A) and (B).
Table 1. Baseline characteristics of the overall study patients (n = 62).
| Baseline characteristic | |
| Gender (M/F) | 40/22 |
| Age (yr) | 59.4 ± 10.5 |
| Past history | |
| ASCVD | 25.8% (16/62) |
| LDL-C > 190 mg/dL | 1.6% (1/62) |
| Diabetes | 16.1% (10/62) |
| 10-year CV risk* > 7.5% | 27.4% (17/62) |
| Neither of above criteria | 29.0% (18/62) |
| Dyslipidemia | 100.0% (62/62) |
| Hypertension | 67.7% (42/62) |
| Gout | 14.5% (9/62) |
| Smoker | 30.6% (19/62) |
| Lipid profile | |
| T-chol (mg/dL) | 236.8 ± 37.8 |
| Triglyceride (mg/dL) | 186.8 ± 171.2 |
| HDL-C (mg/dL) | 53.5 ± 17.3 |
| LDL-C (mg/dL) | 148.6 ± 39.10 |
| L5% | 4.4 ± 6.4 |
| [L5] (mg/dL) | 6.3 ± 9.0 |
ASCVD, atherosclerotic cardiovascular disease; CV, cardiovascular; F, female; HDL-C, high-density lipoprotein-cholesterol; LDL-C, lower density lipoprotein-cholesterol; M, male; T-chol, total cholesterol; TG, triglycerides.
* By pooled cohort equation from ACC/AHA new cholesterol guideline.
Figure 1.
Representative pictures of electronegative LDL pattern on FPLC analysis in patients in SBG versus N-SBG. L5% and [L5] were both higher in SBG patients than those in N-SBG by using the student’s t-test. N-SBG, non-statin benefit group SBG, statin benefit group.
Statin not only effectively reduces LDL-C but also electronegative LDL
After statin therapy, significant reduction of T-chol, LDL-C and triglyceride, as expected, were demonstrated (all p values < 0.05). LDL-C reduction was estimated to be 38.4% in the study, which is compatible with the previous study report with regard to initial rosuvastatin of 10 mg/day. The laboratory data of patients with hyperlipidemia before and after statin (Rosuvastatin 10 mg/day) of 3 months is summarized in Table 2. The atherosclerosis indexes derived by the ratio of total-cholesterol/HDL-C, LDL-C/HDL-C or non-HDL/HDL were also significantly reduced after the 3-month statin therapy (all p values < 0.001). The percentage of L5 reduced from 4.4% to 2.6% by rosuvastatin of 10 mg/day, which was approximately 40.9% reduction and statistically significant (p value = 0.001). With regard to absolute L5 concentration, derived from L5% multiplied by LDL value, there was approximately 63.8% reduction from 6.3 mg/dL to 2.3 mg/dL of absolute L5 (p < 0.001). For apo-lipoprotein analysis, there was significant 30% decrease of apo-B (p < 0.001) but no influence in apo-A1, which translated to the significant reduction of apo-B/apo-A1 ratio (p < 0.001). Glycemic parameters (fasting sugar and HbA1C), as well as hs-CRP, showed no difference before and after the 3-month statin therapy, unlike the uric acid levels, glutamic pyruvic transaminase (GPT) and estimated glomerular filtration rate (eGFR) that showed a slight decrease.
Table 2. Biochemical profiles changes after statin therapy (rosuvastatin 10 mg/day) of 3 months.
| Parameters | Before | After | Difference | Std Err | *p value |
| Sugar (AC) | 116.2 | 111.5 | -4.7 | 6.1 | 0.444 |
| HbA1c | 6.6 | 6.5 | -0.1 | 0.3 | 0.720 |
| T-chol (mg/dL) | 239.7 | 170.3 | -69.4 | 6.0 | < 0.001 |
| TG (mg/dL) | 185.2 | 148.2 | -37 | 16.2 | 0.026 |
| HDL-C (mg/dL) | 54.4 | 54.0 | -0.4 | 1.4 | 0.762 |
| LDL-C (mg/dL) | 151.9 | 93.6 | -58.3 | 5.5 | < 0.001 |
| TC/HDL | 4.7 | 3.4 | -1.3 | 0.2 | < 0.001 |
| nHDL/HDL | 3.7 | 2.4 | -1.3 | 0.2 | < 0.001 |
| LDL/HDL | 3.0 | 1.9 | -1.1 | 0.1 | < 0.001 |
| Apo-B (mg/dL) | 123.4 | 85.1 | -38.3 | 4.4 | < 0.001 |
| Apo-AI (mg/dL) | 148.2 | 149.9 | 1.6 | 3.2 | 0.612 |
| Apo-B/AI | 0.9 | 0.6 | -0.3 | 0.1 | < 0.001 |
| L5 (%) | 4.4 | 2.6 | -1.9 | 0.6 | 0.003 |
| [L5] (mg/dL) | 6.3 | 2.3 | -4.3 | 1.0 | < 0.001 |
| hs-CRP (mg/dL) | 1.7 | 1.6 | -0.1 | 0.3 | 0.802 |
| GPT (mg/dL) | 38.2 | 34.2 | -4.0 | 2.3 | 0.090 |
| Cr (mg/dL) | 0.9 | 0.9 | 0.0 | 0.0 | 0.150 |
| UA (mg/dL) | 6.4 | 6 | -0.4 | 0.2 | 0.042 |
| eGFR (ml/min) | 90.5 | 88.6 | -1.8 | 1.7 | 0.296 |
r, creatinine; eGFR, estimated glomerular filtration rate; GPT, glutamine pyruvate transaminase; HbA1C, glycated hemoglobin A1C; HDL, high-density lipoprotein; hs-CRP, high-sensitivity C-reactive protein; nHDL, non-high-density lipoprotein-cholesterol; Sugar (AC), fasting glycemic level; TC, totol cholesterol; UA, uric acid; the abbreviations are listed as Table 1.
* Paired t-test.
Statin-benefit groups are characterized by higher electronegative LDL levels
Using the criteria of 4 major statin-benefit groups defined by the ACC/AHA new cholesterol guideline, the cohort of 62 asymptomatic patients with hyperlipidemia was divided into the SBG (n = 44) and N-SBG (n = 18) groups (Table 3). Regarding lipid profiles, there were no differences in total cholesterol, triglyceride, LDL-C, HDL-C and the atherosclerotic indexes (total cholesterol/HDL-C, LDL-C/HDL-C or non-HDL-C/HDL-C) and apo-B levels. Significantly higher glycemic index for both fasting sugar and HbA1C were noted in SBG. Relatively, a lower apo-A1 level was found in patients from the SBG (p < 0.05). Notably while the plasma LDL cholesterol levels did not differ between groups (152.8 ± 48.6 vs. 146.9 ± 35.0 mg/dL), the SBG had significantly higher L5% (5.2 ± 7.4% vs. 2.6 ± 1.9%, p < 0.05) and higher absolute L5 concentration (7.4 ± 10.4 vs. 3.7 ± 3.1 mg/dL, p < 0.05), graphically presented in Figure 1(C) and (D).
Table 3. Comparisons of lipid profiles between statin benefit group (SBG) and N-SBG.
| N-SBG (n = 18) | SBG (n = 44) | p-value | |
| Age | 58.9 ± 7.2 | 59.6 ± 11.6 | 0.761 |
| Gender (male) | 42722 | 28/44 | 0.522 |
| BMI (kg/m2) | 24.5 ± 4.3 | 25.6 ± 5.8 | 0.734 |
| Smoker | 42539 | 13/44 | 0.613 |
| Hypertension | 42692 | 31/44 | 0.823 |
| Gout | 42478 | 5/44 | 0.724 |
| T-chol (mg/dL) | 253.1 ± 43.0 | 230.1 ± 33.7 | 0.028 |
| TG (mg/dL) | 210.3 ± 272.2 | 177.2 ± 109.3 | 0.624 |
| HDL (mg/dL) | 59.8 ± 20.4 | 50.9 ± 15.4 | 0.106 |
| LDL (mg/dL) | 152.8 ± 48.6 | 146.9 ± 35.0 | 0.644 |
| FPLC analysis | |||
| L1 (%) | 59.1 ± 26.6 | 53.8 ± 29.4 | 0.490 |
| L2-4 (%) | 38.3 ± 25.8 | 41.0 ± 26.8 | 0.712 |
| L5 (%) | 2.6 ± 1.9 | 5.2 ± 7.4 | 0.031 |
| [L5] (mg/dL) | 3.7 ± 3.1 | 7.4 ± 10.4 | 0.036 |
The changes of lipid profile after receiving 3-month statin therapy
The changes of lipid profile (mg/dL) were also presented as a graph in Figures 2-4, showing how far the distribution was spread from the average for each individual patient’s ΔCHOL, ΔCHOL (%),ΔHDL-C, ΔHDL-C (%),ΔLDL-C, ΔLDL-C (%),ΔL5% and ΔL5 profile for N-SBG and SBG. There were significantly decrease of L5% and [L5] in SBG receiving 3-month statin therapy (before L5%: 5.2 ± 7.4 vs. after L5%: 2.8 ± 3.6; before [L5]: 7.34 ± 10.4 mg/dL vs. after [L5]: 2.6 ± 2.9 mg/dL) (Figure 2C). In contrast, there was no significant difference of L5% in N-SBG receiving 3-month statin therapy (before L5%: 2.6 ± 1.9 vs. after L5%: 1.9 ± 1.2) (Figure 2). However, because total cholesterol and LDL were also decreased in N-SBG (Figure 3), it turned out that [L5] in N-SBG receiving 3-month statin therapy was also significantly decreased (before [L5]: 3.7 ± 3.1 mg/dL vs. after [L5]: 1.6 ± 1.7 mg/dL) (Figure 2). However, there were no differences in the changes of total cholesterol, HDL-C and LDL-C between N-SBG and SBG (Figure 3). The comparison involving changes of L5% and the changes of absolute L5 concentrations between SBG vs. N-SBG yield statistical significance, showing that statin therapy can effectively reduce the L5% and absolute L5 concentration much more in SBG than in N-SBG (Figure 4).
Figure 2.
Graphical comparison of L5% and [L5] of N-SBG and SBG before and after 3 month statin therapy. Each dot represents an individual patient. Abbreviations are in Figure 1.
Figure 4.
Multi-level analysis between N-SBG and SBG for changes in L5% and absolute [[L5] levels for statin treatment of 3 months. Abbreviations are in Figure 1.
Figure 3.
The changes of lipid profile (mg/dL) after receiving 3-month statin therapy was illustrated. Each symbol representing each of the patients that were selected for the study against the average distribution between patients. The graph specifically presents the collected data from the ΔCHOL, ΔCHOL (%), ΔHDL, ΔHDL (%), ΔLDL and ΔLDL (%). CHOL, total cholesterol; HDL, high-density lipoprotein; LDL, low-density lipoprotein; The triangle (delta), the absolute changes; %, the percentage of changes.
Correlation between 10-year cardiovascular risks versus electronegative LDL
One of the SBGs was those with 10-year cardiovascular risk > 7.5% by pool-cohort equation developed and published in the ACC/AHA new cholesterol guideline. The calculator can be downloaded using the link on the AHA website. The linear correlation between electronegative LDL and 10-year cardiovascular risk is illustrated in Figure 5. Excluding those patients with clinical ASCVD (n = 16), linear regression of the rest cohort (n = 46) showed a significantly positive correlation between the plasma L5 concentration and the 10-year cardiovascular risk scored by the pooled cohort equation (r = 0.297, p < 0.05). After 3-month statin therapy, the risk of SBG can be reduced from 20.2 ± 10.9% to 16.3 ± 10.6% in the study (p < 0.0001) (Figure 6), whereas the risk of N-SBG was not significantly reduced (from 4.0 ± 2.2% to 3.3 ± 2.0%; p = 0.145).
Figure 5.
Pearson correlation between plasma L5 concentration and 10-year cardiovascular risk calculated by pooled-cohort equation advocated by the 2013 ACC/AHA new cholesterol guideline showed a positive correlation between the plasma L5 concentration and the 10-year cardiovascular risk scored by the pooled cohort equation. By definition, pool-cohort equation is only for those without clinical ASCVD to calculate the 10-year cardiovascular risks (n = 46).
Figure 6.
Multilevel analysis for 10-year cardiovascular risk for SBG versus N-SBG before and after statin therapy of 3-months. Reduction of 10-year cardiovascular risks by pooled cohort equation after receiving 3-month statin (rosuvastatin 10 mg/day) therapy (n = 46). Abbreviations are in Figure 1.
DISCUSSION
The major findings in this current study showed that atherogenic electronegative LDL, or L5, is much higher in hyperlipidemia patients of SBG, and statin can effectively reduce, while not totally eradicate, the proportion of electronegative LDL. Moreover, the N-SBG had the same levels of LDL-C but less electronegative LDL; therefore, statin therapy might be unnecessary or should be avoided in this group with regard to possible statin-related adverse effects.20-22 Finally, the 10-year cardiovascular risk by pooled cohort equations is closely associated with the electronegative LDL levels.31,32 The results offered the therapeutic rationale of statin use for those 4 major statin-benefit groups defined by ACC/AHA 2013 new cholesterol guideline.13
After the release of ACC/AHA new cholesterol guideline, the practice of lipid management gradually evolved from the LDL target-oriented approach to the outcome-orientated one.33 For patients with documented clinical atherosclerotic cardiovascular diseases (ASCVD), high-intensity statin should be initiated regardless of their LDL-C.34 Such an approach is reasonable because for these patients, statin therapy is for secondary prevention, and the previous report on electronegative LDL showed that L5 concentration is much higher for patients with myocardial infarction and stable coronary artery disease, compared to normal subjects. For patients with type 2 diabetes, who were previously considered as the CVD equivalent, they merit moderate to high-intensity statin therapy for better cardiovascular outcomes. The diabetic dyslipidemia is one of the important issues currently under investigation. The role of electronegative LDL in patients with diabetes or pre-diabetes and metabolic syndrome, along with micro- and macro-vascular abnormalities stems from the diffuse and systemic atherosclerotic changes are currently of substantial research interest. Statin should be prescribed to patients with primary dyslipidemia of high LDL-C > 190 mg/dL, likely because the absolute toxic electronegative LDL might be high even if the L5% is just modestly above the normal range. Finally, the results support the proposition that electronegative LDL is closely associated with 10-year cardiovascular risks; whether the cut-off values of 7.5% coincide with the safe range of electronegative LDL concentration requires further verification (Figure 5).
Electronegative LDL in this study was isolated from human plasma, which directly reflects the toxic component of a patient’s lipid profile. This might represent the concept of “vulnerable” blood that Prof. Eugene Brauwald predicted some ten years ago for continued future advancement in cardiology. Oxidized LDL in a bench experiment can probably exert considerably higher toxicity than electronegative LDL that was isolated from human plasma; however, it was artificially made and not clinically relevant. The parallel of electronegative LDL and statin-benefit concept reinforces the idea that electronegative LDL might be the cumulative effect reflected by the atherosclerotic burden of the entire vascular bed. Statin therapy in the study (by using rosuvastatin 10 mg/day of 3 months) not only reduces 38.4% LDL-C, but also effectively eliminates absolute toxic L5 levels up to 63.8%, which coincides with the previous concept that statin benefit is beyond LDL-C lowering and their pleiotropic effects are appraised. On the contrary, the statin dose in the study might still decrease for patients that need higher-intensive statin therapy to eliminate their residual risks. Much attention for residual risk after powerful LDL-C lowering after statin use has been focused on the enhancement of HDL-C, but currently those large trials evaluating HDL-C enhancing agents appear less than promising. Since electronegative LDL reflects the atherogenic bloods for patients with dyslipidemia, using a higher dose of potent stain or developing another therapeutic approach to eradicate electronegative LDL might clear the residual risk theoretically.
Study limitations
Some limitations to our study should be mentioned. First, most of the study patients with dyslipidemia were enrolled before the new ACC/AHA guideline was released, and the practice of statin prescription was based on the national reimbursement regulation that might be different from other regions. Secondly, only rosuvastatin 10 mg/day for 3 months was chosen for the evaluation of statin effect on electronegative LDL. The effects of other statin, for instance atorvastatin or ezetimibe plus simvastatin, might be different and merit further investigation. Finally, the sample size of the study might be relatively small, though statistical significance was achieved. A larger patient population with a cohort follow-up should be conducted to prove the essential roles of electronegative LDL behind the patients from the statin-benefit groups.
CONCLUSIONS
The four SBGs defined by the 2013 ACC/AHA new cholesterol guideline represent a cohort of high cardiovascular risk and are characterized by increased atherogenic electronegative LDL. However, our study suggests that statin therapy can reduce the electronegative LDL of these 4 major SBGs.
Acknowledgments
The authors abundantly appreciate the bonus grant from Taiwan Society of Cardiology (TSOC) to support the poster abstract of this manuscript presented at the American Heart Association (AHA) scientific sessions 2014 held in Chicago, IL, USA. The work described in this study was also supported in part by grants from MOST-103-2314-B-037-070, KMU-TP103D04, KMTTH-101-005, KMTTH-103-023, KMU-D002-005, the American Diabetes Association (1-04-RA-13), the National Institutes of Health, Heart, Lung, and Blood Institute (HL-63364). The laboratory data of patients with hyperlipidemia before and after statin (rosuvastatin 10 mg/day) of 3 months is summarized in Table 2. Merck/Schering-Plough Pharmaceuticals (research grant), the Mao-Kuei Lin Research Fund of Chicony Electronics, the Stroke Biosignature Program Grant of Academia Sinica in Taiwan (BM1030 10096), Taiwan Ministry of Health and Welfare Clinical Trial and Research Center of Excellence (MOHW104-TDU-B-212-113002).
REFERENCES
- 1.Stone NJ, Robinson JG, Lichtenstein AH, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129:S1–S45. doi: 10.1161/01.cir.0000437738.63853.7a. [DOI] [PubMed] [Google Scholar]
- 2.Smith SC, Jr., Grundy SM. 2013 ACC/AHA guideline recommends fixed-dose strategies instead of targeted goals to lower blood cholesterol. J Am Coll Cardiol. 2014;64:601–612. doi: 10.1016/j.jacc.2014.06.1159. [DOI] [PubMed] [Google Scholar]
- 3.Group AS, Ginsberg HN, Elam MB, et al. Effects of combination lipid therapy in type 2 diabetes mellitus. N Engl J Med. 2010;362:1563–1574. doi: 10.1056/NEJMoa1001282. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Kjekshus J, Apetrei E, Barrios V, et al. Rosuvastatin in older patients with systolic heart failure. N Engl J Med. 2007;357:2248–2261. doi: 10.1056/NEJMoa0706201. [DOI] [PubMed] [Google Scholar]
- 5.Fellstrom BC, Jardine AG, Schmieder RE, et al. Rosuvastatin and cardiovascular events in patients undergoing hemodialysis. N Engl J Med. 2009;360:1395–1407. doi: 10.1056/NEJMoa0810177. [DOI] [PubMed] [Google Scholar]
- 6.Ridker PM, Danielson E, Fonseca FA, et al. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein. N Engl J Med. 2008;359:2195–2207. doi: 10.1056/NEJMoa0807646. [DOI] [PubMed] [Google Scholar]
- 7.Yogo M, Sasaki M, Ayaori M, et al. Intensive lipid lowering therapy with titrated rosuvastatin yields greater atherosclerotic aortic plaque regression: serial magnetic resonance imaging observations from RAPID study. Atherosclerosis. 2014;232:31–39. doi: 10.1016/j.atherosclerosis.2013.10.007. [DOI] [PubMed] [Google Scholar]
- 8.Ramjee V, Eapen DJ, Sperling LS. Optimal lipid targets for the new era of cardiovascular prevention. Ann N Y Acad Sci. 2012;1254:106–114. doi: 10.1111/j.1749-6632.2012.06478.x. [DOI] [PubMed] [Google Scholar]
- 9.Masuda J, Tanigawa T, Yamada T, et al. Effect of combination therapy of ezetimibe and rosuvastatin on regression of coronary atherosclerosis in patients with coronary artery disease. Int Heart J. 2015;56:278–285. doi: 10.1536/ihj.14-311. [DOI] [PubMed] [Google Scholar]
- 10.Choi YH, Kim Y, Hyeon CW, et al. Influence of previous statin therapy on cholesterol-lowering effect of ezetimibe. Korean Circ J. 2014;44:227–232. doi: 10.4070/kcj.2014.44.4.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Khera AV, Qamar A, Reilly MP, et al. Effects of niacin, statin, and fenofibrate on circulating proprotein convertase subtilisin/kexin type 9 levels in patients with dyslipidemia. Am J Cardiol. 2015;115:178–182. doi: 10.1016/j.amjcard.2014.10.018. [DOI] [PubMed] [Google Scholar]
- 12.Franceschini G, Favari E, Calabresi L, et al. Differential effects of fenofibrate and extended-release niacin on high-density lipoprotein particle size distribution and cholesterol efflux capacity in dyslipidemic patients. J Clin Lipidol. 2013;7:414–422. doi: 10.1016/j.jacl.2013.06.007. [DOI] [PubMed] [Google Scholar]
- 13.Diaz Rodriguez A. Guidelines for the management of dyslipidemia. Semergen. 2014;40 Suppl 4:19–25. doi: 10.1016/S1138-3593(14)74393-X. [DOI] [PubMed] [Google Scholar]
- 14.Cherubini A, Palomba A, Morosin M, et al. Achieving optimal cholesterol levels in patients with chronic ischemic heart disease: from guidelines to the real world. G Ital Cardiol (Rome) 2015;16:240–249. doi: 10.1714/1848.20190. [DOI] [PubMed] [Google Scholar]
- 15.Duschek N, Stojakovic T, Ghai S, et al. Ratio of apolipoprotein A-II/B improves risk prediction of postoperative survival after carotid endarterectomy. Stroke. 2015;46:1700–1703. doi: 10.1161/STROKEAHA.115.009663. [DOI] [PubMed] [Google Scholar]
- 16.Profumo E, Buttari B, Saso L, Rigano R. Pleiotropic effects of statins in atherosclerotic disease: focus on the antioxidant activity of atorvastatin. Curr Top Med Chem. 2014;14:2542–2551. doi: 10.2174/1568026614666141203130324. [DOI] [PubMed] [Google Scholar]
- 17.Kotyla PJ. Pleiotropic activity of 3-hydroxy-3-methyl-glutharyl-coenzyme a inhibitors (statins). Therapeutic potential in connective tissue diseases. Ann Acad Med Stetin. 2014;60:39–45. [PubMed] [Google Scholar]
- 18.Takayama T, Hiro T, Ueda Y, et al. Plaque stabilization by intensive LDL-cholesterol lowering therapy with atorvastatin is delayed in type 2 diabetic patients with coronary artery disease-serial angioscopic and intravascular ultrasound analysis. J Cardiol. 2013;61:381–386. doi: 10.1016/j.jjcc.2013.01.010. [DOI] [PubMed] [Google Scholar]
- 19.Athyros VG, Katsiki N, Karagiannis A, Mikhailidis DP. High-intensity statin therapy and regression of coronary atherosclerosis in patients with diabetes mellitus. J Diabetes Complications. 2015;29:142–145. doi: 10.1016/j.jdiacomp.2014.10.004. [DOI] [PubMed] [Google Scholar]
- 20.Pirillo A, Catapano AL. Statin intolerance: diagnosis and remedies. Curr Cardiol Rep. 2015;17:582. doi: 10.1007/s11886-015-0582-z. [DOI] [PubMed] [Google Scholar]
- 21.Bjornsson ES. Drug-induced liver injury: an overview over the most critical compounds. Arch Toxicol. 2015;89:327–334. doi: 10.1007/s00204-015-1456-2. [DOI] [PubMed] [Google Scholar]
- 22.Banach M, Rizzo M, Toth PP, et al. Statin intolerance - an attempt at a unified definition. Position paper from an International Lipid Expert Panel. Arch Med Sci. 2015;11:1–21. doi: 10.5114/aoms.2015.49807. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Kinikini D, Sarfati MR, Mueller MT, et al. Meeting AHA/ACC secondary prevention goals in a vascular surgery practice: an opportunity we cannot afford to miss. J Vasc Surg. 2006;43:781–787. doi: 10.1016/j.jvs.2005.12.002. [DOI] [PubMed] [Google Scholar]
- 24.Kuliczkowska-Plaksej J, Bednarek-Tupikowska G, Plaksej R, Filus A. Scavenger receptor CD36: its expression, regulation, and role in the pathogenesis of atherosclerosis. Part I. Postepy Hig Med Dosw (Online) 2006;60:142–151. [PubMed] [Google Scholar]
- 25.Stemmer U, Dunai ZA, Koller D, et al. Toxicity of oxidized phospholipids in cultured macrophages. Lipids Health Dis. 2012;11:110. doi: 10.1186/1476-511X-11-110. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Torzewski M, Klouche M, Hock J, et al. Immunohistochemical demonstration of enzymatically modified human LDL and its colocalization with the terminal complement complex in the early atherosclerotic lesion. Arterioscler Thromb Vasc Biol. 1998;18:369–378. doi: 10.1161/01.atv.18.3.369. [DOI] [PubMed] [Google Scholar]
- 27.Puri R, Nissen SE. The complementary roles of imaging and ‘omics’ for future anti-atherosclerotic drug development. Curr Pharm Des. 2013;19:5963–5971. doi: 10.2174/13816128113199990365. [DOI] [PubMed] [Google Scholar]
- 28.Torimoto K, Okada Y, Mori H, et al. Efficacy of combination of ezetimibe 10 mg and rosuvastatin 2.5 mg versus rosuvastatin 5 mg monotherapy for hypercholesterolemia in patients with type 2 diabetes. Lipids Health Dis. 2013;12:137. doi: 10.1186/1476-511X-12-137. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Greco G, Balogh G, Brunelli R, et al. Generation in human plasma of misfolded, aggregation-prone electronegative low density lipoprotein. Biophysical Journal. 2009;97:628–635. doi: 10.1016/j.bpj.2009.05.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Chu CS, Wang YC, Lu LS, et al. Electronegative low-density lipoprotein increases C-reactive protein expression in vascular endothelial cells through the LOX-1 receptor. PloS One. 2013;8:e70533. doi: 10.1371/journal.pone.0070533. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Schiros CG, Denney TS, Jr., Gupta H, et al. Interaction analysis of the new pooled cohort equations for 10-year atherosclerotic cardiovascular disease risk estimation: a simulation analysis. BMJ Open. 2015;5:e006468. doi: 10.1136/bmjopen-2014-006468. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Karmali KN, Goff DC, Jr., Ning H, et al. A systematic examination of the 2013 ACC/AHA pooled cohort risk assessment tool for atherosclerotic cardiovascular disease. J Am Coll Cardiol. 2014;64:959–968. doi: 10.1016/j.jacc.2014.06.1186. [DOI] [PubMed] [Google Scholar]
- 33.Gencer B, Auer R, Nanchen D, et al. Expected impact of applying new 2013 AHA/ACC cholesterol guidelines criteria on the recommended lipid target achievement after acute coronary syndromes. Atherosclerosis. 2015;239:118–124. doi: 10.1016/j.atherosclerosis.2014.12.049. [DOI] [PubMed] [Google Scholar]
- 34.Stegman B, Puri R, Cho L, et al. High-intensity statin therapy alters the natural history of diabetic coronary atherosclerosis: insights from SATURN. Diabetes Care. 2014;37:3114–3120. doi: 10.2337/dc14-1121. [DOI] [PubMed] [Google Scholar]