Reduction In apoB Research Articles

Beyond LDL-cholesterol: effects of alirocumab on the human apolipoproteome

Abstract Introduction The PACMAN-AMI (Effects of the PCSK9 Antibody Alirocumab on Coronary Atherosclerosis in Patients With Acute Myocardial Infarction) trial enrolled 300 participants with longitudinal plasma samples available at four time points (enrollment, 24 hours, 4 weeks, 52 weeks), of which 266 completed the 52-week follow-up. Purpose Expanding on a previous investigation employing apolipoprotein proteomics in patients with coronary heart disease, the current study aimed to evaluate the impact of the monoclonal antibody alirocumab on apolipoprotein and proprotein convertase subtilisin/kexin type 9 (PCSK9) levels. Methods A mass spectrometry assay was employed to quantify 15 apolipoproteins. Linear mixed-effects models assessed the impact of timepoints and treatments (alirocumab: n = 131, placebo: n = 135, in addition to statins) on apolipoprotein levels. Results Alirocumab led to a fast rise in PCSK9 levels, with a marked increase [inter-quartile range] of 262% [207%] as early as 24 hours after treatment initiation, followed by more pronounced elevations at 4 weeks and 52 weeks, reaching 1575% [813%] and 1480% [747%], respectively (P < 0.001 for all comparisons). At 52 weeks, the ApoB reduction compared with enrollment was -75% [10%] with alirocumab vs. -43% [19%] with placebo (P < 0.001, between groups), while the change in LDL-C was -88% [9%] with alirocumab vs. -54% [19%] with placebo (P < 0.001). Alongside significantly greater reductions in ApoC2 (P = 0.0041) and ApoC3 (P < 0.001) with alirocumab, ApoE changed by -41.6% [21.1%] with alirocumab compared to -15.4% [24.5%] with placebo (P < 0.001). Overall, there was no impact on Apo(a) levels compared to baseline. Conclusion The rapid increase in PCSK9 levels after 24 hours suggests immediate immunocomplex formation. A compensatory rise in PCSK9 production may contribute to later elevations. Alirocumab not only lowered LDL-C but also achieved a sustained reduction in very low-density lipoprotein-associated apolipoproteins (ApoC2, ApoC3, and ApoE), indicating additional benefits of PCSK9 inhibitors.

Abstract 2048: Pla2g12b Is Critical For Intestinal Lipid Absorption In Mice

We previously showed that Pla2g12bhlb218/hlb218 (Pla2g12bmt/mt) mice injected with viruses expressing mutant PCSK9, fed a western diet had significantly lower plasma lipids and fewer atherosclerotic plaques. Here, we aimed to explain mechanisms for resistance to hyperlipidemia and atherosclerosis in these mice. We performed studies in 3-month-old male and female chow fed Pla2g12bmt/mt and control mice. Dual x-ray absorptiometry did not reveal any significant differences in body weight, fat weight and fat percentage in Pla2g12bmt/mt mice compared to controls. Moreover, there were no significant differences in energy expenditure and food intake between mutant and control mice. However, these mice had significantly lower levels of plasma glucose, insulin, triglyceride, cholesterol, HDL-c, LDL-c, apoB48, and apoB100. In oral fat tolerance test Pla2g12bmt/mt mice showed significant defects in triglyceride absorption. Furthermore, these mice excreted more fecal triglyceride, but not cholesterol. Oil Red O, H & E staining, transmission electron microscopy, and quantifications of lipids in the duodenum indicated accumulation of large lipid droplets and dilated endoplasmic reticulum. These studies suggest that Pla2g12bmt/mt mice have significant defect in intestinal fat absorption. These defects were not due to reductions in apoB and MTP expression. RNA-Seq analysis of duodenal samples revealed upregulation of glycerolipid metabolism, arachidonic acid metabolism, oxidative phosphorylation, and thermogenesis. These pathways were likely upregulated to increase cellular catabolism and oxidation of accumulated lipids. Down upregulated pathways were related to pancreatic secretion, protein digestion and absorption. Despite severe defects in fat absorption, these mice maintain normal growth and physiology. These mice may serve as model to understand metabolism in hypolipidemia disorders associated with significant defects in lipid absorption such as abetalipoproteinemia and hypobetalipoproteinemia.

Lipid-lowering drugs affect lung cancer risk via sphingolipid metabolism: a drug-target Mendelian randomization study.

Background: The causal relationship between lipid-lowering drug (LLD) use and lung cancer risk is controversial, and the role of sphingolipid metabolism in this effect remains unclear. Methods: Genome-wide association study data on low-density lipoprotein (LDL), apolipoprotein B (ApoB), and triglycerides (TG) were used to develop genetic instrumental variables (IVs) for LLDs. Two-step Mendelian randomization analyses were performed to examine the causal relationship between LLDs and lung cancer risk. The effects of ceramide, sphingosine-1-phosphate (S1P), and ceramidases on lung cancer risk were explored, and the proportions of the effects of LLDs on lung cancer risk mediated by sphingolipid metabolism were calculated. Results: APOB inhibition decreased the lung cancer risk in ever-smokers via ApoB (odds ratio [OR] 0.81, 95% confidence interval [CI] 0.70-0.92, p = 0.010), LDL (OR 0.82, 95% CI 0.71-0.96, p = 0.040), and TG (OR 0.63, 95% CI 0.46-0.83, p = 0.015) reduction by 1 standard deviation (SD), decreased small-cell lung cancer (SCLC) risk via LDL reduction by 1 SD (OR 0.71, 95% CI 0.56-0.90, p = 0.016), and decreased the plasma ceramide level and increased the neutral ceramidase level. APOC3 inhibition decreased the lung adenocarcinoma (LUAD) risk (OR 0.60, 95% CI 0.43-0.84, p = 0.039) but increased SCLC risk (OR 2.18, 95% CI 1.17-4.09, p = 0.029) via ApoB reduction by 1 SD. HMGCR inhibition increased SCLC risk via ApoB reduction by 1 SD (OR 3.04, 95% CI 1.38-6.70, p = 0.014). The LPL agonist decreased SCLC risk via ApoB (OR 0.20, 95% CI 0.07-0.58, p = 0.012) and TG reduction (OR 0.58, 95% CI 0.43-0.77, p = 0.003) while increased the plasma S1P level. PCSK9 inhibition decreased the ceramide level. Neutral ceramidase mediated 8.1% and 9.5% of the reduced lung cancer risk in ever-smokers via ApoB and TG reduction by APOB inhibition, respectively, and mediated 8.7% of the reduced LUAD risk via ApoB reduction by APOC3 inhibition. Conclusion: We elucidated the intricate interplay between LLDs, sphingolipid metabolites, and lung cancer risk. Associations of APOB, APOC3, and HMGCR inhibition and LPL agonist with distinct lung cancer risks underscore the multifaceted nature of these relationships. The observed mediation effects highlight the considerable influence of neutral ceramidase on the lung cancer risk reduction achieved by APOB and APOC3 inhibition.

Efficacy and Safety of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors as Adjuvant Treatments for Patients with Hypercholesterolemia Treated with Statin: A Systematic Review and Network Meta-analysis.

Background: The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are potent LDL-C lowering agents. However, few head-to-head studies evaluated the efficacy on the lowering in other atherogenic apolipoproteins and safety of PCSK9 inhibitors at different dosages as an add-on statins therapy in hypercholesterolemia patients. Methods: This study is a systematic review and network meta-analysis of randomized control trials to compare the efficacy of lipid reduction and adverse events of PCSK9 inhibitors in statin-treated hypercholesterolemia patients. PubMed, EMBASE, and Cochrane Library databases were searched till April 20, 2021, for randomized controlled trials. Random-effect network meta-analyses were undertaken to compare the differences in the percent reduction in low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (ApoB), and lipoprotein (a) [Lp(a)] levels and the risk of AEs among different PCSK9 inhibitors. Results: A total of 22 articles with 42,786 patients were included. The lipid reductions in LDL-C, ApoB, and Lp(a) with add-on PCSK9 inhibitors vs. placebo in statin-treated patients across all trials were 50–63%, 43–52%, and 23–31%, respectively. Evolocumab 140 mg Q2W was ranked the best among all treatment strategies for lowering LDL-C, ApoB, and Lp(a) levels, and the treatment difference was 68.05% (95% confidence interval (CI), 62.43% to 73.67) in LDL-C reduction, 54.95% (95% CI, 49.55% to 60.35%) in ApoB reduction, and 34.25% (95% CI, 27.59% to 40.91%) in Lp(a) reduction compared with the placebo. No significant risk difference of adverse events between PCSK9 inhibitors and placebo was found. Conclusion: PCSK9 inhibitors showed a significant effect on the reduction in LDL-C, ApoB, and Lp(a) levels in statin-treated patients. Evolocumab 140 mg Q2W showed significantly larger degrees of LDL-C, ApoB, and Lp(a) reduction.

Cholesteryl ester transfer protein inhibitors: from high-density lipoprotein cholesterol to low-density lipoprotein cholesterol lowering agents?

Cholesteryl ester transfer protein (CETP) is a liver-synthesized glycoprotein whose main functions are facilitating transfer of both cholesteryl esters from high-density lipoprotein (HDL) particles to apolipoprotein B (apoB)-containing particles as well as transfer of triglycerides from apoB-containing particles to HDL particles. Novel crystallographic data have shown that CETP exchanges lipids in the circulation by a dual molecular mechanism. Recently, it has been suggested that the atherosclerotic cardiovascular disease (ASCVD) benefit from CETP inhibition is the consequence of the achieved low-density lipoprotein cholesterol (LDL-C) and apoB reduction, rather than through the HDL cholesterol (HDL-C) increase. The use of CETP inhibitors is supported by genetic evidence from Mendelian randomization studies, showing that LDL-C lowering by CETP gene variants achieves equal ASCVD risk reduction as LDL-C lowering through gene proxies for statins, ezetimibe, and proprotein convertase subtilisin-kexin Type 9 inhibitors. Although first-generation CETP inhibitors (torcetrapib, dalcetrapib) were mainly raising HDL-C or had off-target effects, next generation CETP inhibitors (anacetrapib, evacetrapib) were also effective in reducing LDL-C and apoB and have been proven safe. Anacetrapib was the first CETP inhibitor to be proven effective in reducing ASCVD risk. In addition, CETP inhibitors have been shown to lower the risk of new-onset diabetes, improve glucose tolerance, and insulin sensitivity. The newest-generation CETP inhibitor obicetrapib, specifically designed to lower LDL-C and apoB, has achieved significant reductions of LDL-C up to 45%. Obicetrapib, about to enter phase III development, could become the first CETP inhibitor as add-on therapy for patients not reaching their guideline LDL-C targets.

Non-invasive skin cholesterol testing: a potential proxy for LDL-C and apoB serum measurements

BackgroundLipid management is the first line of treatment for decreasing the incidence of cardiovascular events in patients with coronary heart disease (CHD), and a variety of indicators are used to evaluate lipid management. This work analyses the differences in LDL-C and apoB for lipid management evaluation, as well as explores the feasibility of skin cholesterol as a marker that can be measured non-invasively for lipid management.MethodsThe prospective study enrolled 121 patients who had been diagnosed with acute coronary syndrome (ACS) at the department of emergency medicine of the First Affiliated Hospital of the USTC from May 2020 to January 2021, and the patients were grouped into Group I (n=53) and Group II (n=68) according to whether they had comorbid hyperlipidemia and/or diabetes mellitus. All patients were administered 10 mg/day of rosuvastatin and observed for 12 weeks. Lipid management was assessed on the basis of LDL-C and apoB, and linear correlation models were employed to assess the relationship between changes in these well accepted markers to that of changes in skin cholesterol.ResultsOut of 121 patients with ACS, 53 patients (43.80 %) had combined hyperlipidemia and/or diabetes mellitus (Group I), while 68 patients (56.20 %) did not (Group II). Cardiovascular events occur at earlier ages in patients with CHD who are comorbid for hyperlipidemia and/or diabetes (P<0.05). LDL-C attainment rate is lower than apoB attainment rate with rosuvastatin therapy (P<0.05), which is mainly attributable to patients with low initial LDL-C. Skin cholesterol reduction correlated with LDL-C reduction. (r=0.501, P<0.001) and apoB reduction (r=0.538, P<0.001). Skin cholesterol reduction continued over all time points measured.ConclusionsExamination of changes in apoB levels give patients with low initial LDL-C more informative data on lipid management than LDL-C readings. In addition, non-invasive skin cholesterol measurements may have the potential to be used independently for lipid management evaluation.

The next generation of triglyceride-lowering drugs: will reducing apolipoprotein C-III or angiopoietin like protein 3 reduce cardiovascular disease?

Apolipoprotein C-III (ApoC-III) and angiopoietin like protein 3 (angptl3) have emerged as key regulators of triglyceride metabolism. Based on Mendelian randomisation studies, novel therapeutic strategies inhibiting these proteins using monoclonal antibodies or gene silencing techniques might reduce residual cardiovascular disease (CVD) risk in dyslipidemic patients. This article aims to review the role of apoC-III and angptl3 in triglyceride metabolism and combine early clinical evidence of CVD reducing potential of these new therapeutic targets. Angptl3 inhibition by mAb or antisense therapy has recently completed phase I and II studies, respectively and demonstrate robust apolipoprotein B (apoB) lowering up to 46%. Volanesorsen is an antisense therapy approved for patients with extremely elevated plasma triglyceride levels in which it showed no consistent apoB reduction. However, the GalNAc-conjugated oligonucleotide showed moderate (up to ∼30%) apoB reduction in a phase 1/2a dose-finding study. Angptl3 and apoC-III are novel targets in lipoprotein metabolism that reduce triglycerides when inhibited. The expected CVD risk reduction may be mediated through reduced triglyceride-rich lipoprotein particle number, reflected by apoB, rather than triglyceride reduction per se. Limited human evidence shows that apoC-III and angptl3 inhibition both potently lower triglycerides, but since angptl3 inhibition reduces apoB more robustly it may be expected to confer more favorable CVD risk reduction.

Comparison of the Efficacy of Rosuvastatin Monotherapy 20 mg with Rosuvastatin 5 mg and Ezetimibe 10 mg Combination Therapy on Lipid Parameters in Patients with Type 2 Diabetes Mellitus

BackgroundThe apolipoprotein B/A1 (apoB/A1) ratio is a stronger predictor of future cardiovascular disease than is the level of conventional lipids. Statin and ezetimibe combination therapy have shown additional cardioprotective effects over statin monotherapy.MethodsThis was a single-center, randomized, open-label, active-controlled study in Korea. A total of 36 patients with type 2 diabetes mellitus were randomized to either rosuvastatin monotherapy (20 mg/day, n=20) or rosuvastatin/ezetimibe (5 mg/10 mg/day, n=16) combination therapy for 6 weeks.ResultsAfter the 6-week treatment, low density lipoprotein cholesterol (LDL-C) and apoB reduction were comparable between the two groups (−94.3±15.4 and −62.0±20.9 mg/dL in the rosuvastatin group, −89.9±22.7 and −66.8±21.6 mg/dL in the rosuvastatin/ezetimibe group, P=0.54 and P=0.86, respectively). In addition, change in apoB/A1 ratio (−0.44±0.16 in the rosuvastatin group and −0.47±0.25 in the rosuvastatin/ezetimibe group, P=0.58) did not differ between the two groups. On the other hand, triglyceride and free fatty acid (FFA) reductions were greater in the rosuvastatin/ezetimibe group than in the rosuvastatin group (−10.5 mg/dL [interquartile range (IQR), −37.5 to 29.5] and 0.0 µEq/L [IQR, −136.8 to 146.0] in the rosuvastatin group, −49.5 mg/dL [IQR, −108.5 to −27.5] and −170.5 µEq/L [IQR, −353.0 to 0.8] in the rosuvastatin/ezetimibe group, P=0.010 and P=0.049, respectively). Both treatments were generally well tolerated, and there were no differences in muscle or liver enzyme elevation.ConclusionA 6-week combination therapy of low-dose rosuvastatin and ezetimibe showed LDL-C, apoB, and apoB/A1 ratio reduction comparable to that of high-dose rosuvastatin monotherapy in patients with type 2 diabetes mellitus. Triglyceride and FFA reductions were greater with the combination therapy than with rosuvastatin monotherapy.

Effect of Ezetimibe Add-On Therapy on Non-HDL-C in Type 2 Diabetes Subjects—A Post-Hoc Analysis of RESEARCH Study

Background: In RESEARCH study, we demonstrated the superiority of ezetimibe add-on therapy over statin-doubling in T2DM.Non-HDL-C is attracting attention as an index including TG rich lipoproteins reflecting insulin resistance in diabetics. Methods: 109 T2DM adults with LDL-C &amp;gt;=120 mg/dL (&amp;gt;=100 mg/dL in secondary preventive) despite statin treatment were randomly assigned to statin doubling group (S) or adding ezetimibe (E) for 12 weeks.As a post-hoc analysis, non-HDL-C change and TG rich lipoproteins were analyzed. Results: The rate of non-HDL-C reduction was significantly greater in E(20.9%) than in S(8.3%). Assuming the non-HDL-C target as &amp;lt;150 mg/dl (&amp;lt;130 mg/dl for secondary preventive), the achievement rate was significantly higher in E(88.7%) than in S(57.1%). The rates of apoB and apoE reduction were significantly larger in E (apoB 14.8% and apoE 7.7%) than in S (apoB 9.0% and apoE 2.9%). By regression analysis, apoE change rate showed correlation with sd-LDL change rate or RLP-C change rate, respectively, with larger correlation and regression coefficient in E. The percentage change in non-HDL-C was correlated with the percentage change in sd-LDL, with larger regression coefficient in E. Analysis was also made for 43 subjects with TG&amp;gt;=150 mg/dl before treatment, and 73 subjects without achievement in the non-HDL-C target before treatment. Non-HDL-C reduction rates were greater in E (21.1% and 25.1%) than in S (8.9% and 8.7%), respectively. Target achievement rates were also significantly larger in E (77.8% and 83.9%) than in S (48.0% and 42.9%). ApoB reduction was 13.2% and 11.6% in S, and 12.5% and 17.1% E, and apoE reduction was 9.4% and 5.4% in S and 13.0% and 9.4% in E, respectively. The correlation of change rates showed almost the same tendency compared to the whole population. Conclusion: Ezetimibe combination therapy effectively reduced non-HDL-C reflecting TG rich lipoproteins, compared with statin-doubling therapy. Disclosure K. Sakamoto: None. M. Kawamura: None. M. Tagami: None. A. Tanaka: Research Support; Self; Daiichi Sankyo Company, Limited. Speaker's Bureau; Self; Merck Sharp &amp; Dohme Corp., Kewpie Corporation. Y. Mori: None. T. Hirano: Speaker's Bureau; Self; Novo Nordisk Inc., AstraZeneca. T. Shiba: Speaker's Bureau; Self; Shionogi &amp; Co., Ltd., Pfizer Inc., Merck Sharp &amp; Dohme Corp., Kowa Company, Ltd., Daiichi Sankyo Company, Limited.

Loss-of-function mutations in Zn-finger DNA-binding domain of HNF4A cause aberrant transcriptional regulation in liver cancer.

Hepatocyte nuclear factors (HNF) are transcription factors that crucially regulate cell-specific gene expression in many tissues, including the liver. Of these factors, HNF4A acts both as a master regulator of liver organogenesis and a tumor suppressor in the liver. In our whole genome sequencing analysis, we found seven somatic mutations (three Zn-finger mutations, three deletion mutants, and one intron mutation) of HNF4A in liver cancers. Interestingly, three out of seven mutations were clustered in its Zn-finger DNA-binding domain; G79 and F83 are positioned in the DNA recognition helix and the sidechain of M125 is sticking into the core of domain. These mutations are likely to affect DNA interaction from a structural point of view. We then generated these mutants and performed in-vitro promoter assays as well as DNA binding assays. These three mutations reduced HNF4 transcriptional activity at promoter sites of HNF4A-target genes. Expectedly, this decrease in transcriptional activity was associated with a change in DNA binding. RNA-Seq analysis observed a strong correlation between HNF4A expression and expression of its target genes, ApoB and HNF1A, in liver cancers. Since knockdown of HNF4A caused a reduction in ApoB and HNF1A expression, possibly loss of HNF4 reduces the expression of these genes and subsequently tumor growth is triggered. Therefore, we propose that HNF4A mutations G79C, F83C, and M125I are functional mutations found in liver cancers and that loss of HNF4A function, through its mutation, leads to a reduction in HNF1A and ApoB gene expression with a concomitant increased risk of liver tumorigenesis.

Short-term isocaloric fructose restriction lowers apoC-III levels and yields less atherogenic lipoprotein profiles in children with obesity and metabolic syndrome

Background and aimsDietary fructose may play a role in the pathogenesis of metabolic syndrome (MetS). In a recently published study of obese children with MetS, we showed that isocaloric fructose restriction reduced fasting triglyceride (TG) and LDL-cholesterol (LDL-C). In these ancillary analyses, we tested the hypothesis that these effects were also accompanied by improved quantitative and qualitative changes in LDL and HDL subclasses and their apolipoproteins; as well as change in VLDL, particularly apoC-III. MethodsObese children with MetS (n = 37) consumed a diet that matched self-reported macronutrient composition for nine days, with the exception that dietary fructose was reduced from 11.7 ± 4.0% to 3.8 ± 0.5% of daily calories and substituted with glucose (in starch). Participants underwent fasting biochemical analyses on Days 0 and 10. HDL and LDL subclasses were analyzed using the Lipoprint HDL and LDL subfraction analysis systems from Quantimetrix. ResultsSignificant reductions in apoB (78 ± 24 vs. 66 ± 24 mg/dl) apoC-III (8.7 ± 3.5 vs. 6.5 ± 2.6 mg/dl) and apoE (4.6 ± 2.3 vs. 3.6 ± 1.1 mg/dl), all p < 0.001) were observed. LDL size increased by 0.87 Å (p = 0.008). Small dense LDL was present in 25% of our cohort and decreased by 68% (p = 0.04). Small HDL decreased by 2.7% (p < 0.001) and large HDL increased by 2.4% (p = 0.04). The TG/HDL-C ratio decreased from 3.1 ± 2.5 to 2.4 ± 1.4 (p = 0.02). These changes in fasting lipid profiles correlated with changes in insulin sensitivity. ConclusionsIsocaloric fructose restriction for 9 days improved lipoprotein markers of CVD risk in children with obesity and MetS. The most dramatic reduction was seen for apoC-III, which has been associated with atherogenic hypertriglyceridemia.

Acute modification in plasma lipid levels in ultramarathon runners

ABSTRACTWe aimed to evaluate the effects of a 24-h ultramarathon, an aerobic test of high physical load, on lipid profile and apolipoproteins B (ApoB) and A1 (ApoA1) levels, minimally modified low-density lipoprotein (LDL), and oxidised LDL. Prospective evaluation of 16 male athletes who participated in an ultramarathon run, where the objective was to run the greatest distance possible in 24 h. Fourteen participants completed the run. The mean distance achieved was 133.1 km (maximum of 169.6 km). There was a trend in reduction of triglycerides and total cholesterol (P = 0.06 and 0.05, respectively), without significant modifications in high-density lipoprotein, LDL and ApoA1 levels (P = 0.16; 0.55 and 0.67). There was a marked reduction in ApoB levels (P < 0.001), correlated directly to the distance covered (Pearson R = 0.68). Accordingly, an increase in the LDL/ApoB ratio was observed. The stress of this physical activity was not associated to an increase in minimally modified LDL or oxidised LDL. Lipid profile levels were not acutely altered by prolonged physical activity. Similarly, there was no evidence of greater oxidation of LDL over a 24-h period of physical activity. The reduction in ApoB was directly proportional to the distance covered, suggesting an acute positive change in phenotype of LDL molecules.

Dabigatran etexilate and reduction in serum apolipoprotein B

ObjectiveCarboxylesterases, which convert dabigatran etexilate to its active form, dabigatran, have also been shown to influence lipoprotein metabolism, although any pleotropic effects of the drug based on this possible mechanism...

Association between LDL-C, Non HDL-C, and Apolipoprotein B Levels with Coronary Plaque Regression.

BackgroundPrevious reports have inferred a linear relationship between LDL-C and changes in coronary plaque volume (CPV) measured by intravascular ultrasound. However, these publications included a small number of studies and did not explore other lipid markers.ObjectiveTo assess the association between changes in lipid markers and regression of CPV using published data.MethodsWe collected data from the control, placebo and intervention arms in studies that compared the effect of lipidlowering treatments on CPV, and from the placebo and control arms in studies that tested drugs that did not affect lipids. Baseline and final measurements of plaque volume, expressed in mm3, were extracted and the percentage changes after the interventions were calculated. Performing three linear regression analyses, we assessed the relationship between percentage and absolute changes in lipid markers and percentage variations in CPV.ResultsTwenty-seven studies were selected. Correlations between percentage changes in LDL-C, non-HDL-C, and apolipoprotein B (ApoB) and percentage changes in CPV were moderate (r = 0.48, r = 0.47, and r = 0.44, respectively). Correlations between absolute differences in LDL-C, non‑HDL-C, and ApoB with percentage differences in CPV were stronger (r = 0.57, r = 0.52, and r = 0.79). The linear regression model showed a statistically significant association between a reduction in lipid markers and regression of plaque volume.ConclusionA significant association between changes in different atherogenic particles and regression of CPV was observed. The absolute reduction in ApoB showed the strongest correlation with coronary plaque regression.

Relations of change in plasma levels of LDL-C, non-HDL-C and apoB with risk reduction from statin therapy: a meta-analysis of randomized trials.

BackgroundIdentifying the best markers to judge the adequacy of lipid‐lowering treatment is increasingly important for coronary heart disease (CHD) prevention given that several novel, potent lipid‐lowering therapies are in development. Reductions in LDL‐C, non‐HDL‐C, or apoB can all be used but which most closely relates to benefit, as defined by the reduction in events on statin treatment, is not established.Methods and ResultsWe performed a random‐effects frequentist and Bayesian meta‐analysis of 7 placebo‐controlled statin trials in which LDL‐C, non‐HDL‐C, and apoB values were available at baseline and at 1‐year follow‐up. Summary level data for change in LDL‐C, non‐HDL‐C, and apoB were related to the relative risk reduction from statin therapy in each trial. In frequentist meta‐analyses, the mean CHD risk reduction (95% CI) per standard deviation decrease in each marker across these 7 trials were 20.1% (15.6%, 24.3%) for LDL‐C; 20.0% (15.2%, 24.7%) for non‐HDL‐C; and 24.4% (19.2%, 29.2%) for apoB. Compared within each trial, risk reduction per change in apoB averaged 21.6% (12.0%, 31.2%) greater than changes in LDL‐C (P<0.001) and 24.3% (22.4%, 26.2%) greater than changes in non‐HDL‐C (P<0.001). Similarly, in Bayesian meta‐analyses using various prior distributions, Bayes factors (BFs) favored reduction in apoB as more closely related to risk reduction from statins compared with LDL‐C or non‐HDL‐C (BFs ranging from 484 to 2380).ConclusionsUsing both a frequentist and Bayesian approach, relative risk reduction across 7 major placebo‐controlled statin trials was more closely related to reductions in apoB than to reductions in either non‐HDL‐C or LDL‐C.

Rare LPL gene variants attenuate triglyceride reduction and HDL cholesterol increase in response to fenofibric acid therapy in individuals with mixed dyslipidemia

ObjectiveIndividuals with mixed dyslipidemia have elevated triglycerides (TG), low high-density lipoprotein cholesterol (HDL-C), and increased risk for coronary disease. Fibrate therapy is commonly used to lower TG and increase HDL-C. Common genetic variants are known to affect the response to fibrate therapy. We sought to identify rare genetic variants (frequency ≤ 1%) in genes involved in TG and HDL-C metabolism that affect the response to fenofibric acid (FA) therapy. MethodsFour genes with a major role in HDL-C and TG metabolism APOA1, APOC2, APOC-III and LPL were sequenced in 2385 participants with mixed dyslipidemia in a randomized, double-blind, active-controlled study comparing therapy with FA alone, in combination with statins, or statin alone. Rare variants collapsing or SKAT methods were used for the analysis. ResultsSynonymous rare variants in the LPL gene were significantly associated with absolute HDL-C change (P = 9 × 10−4) and TG percent change (P = 6.76 × 10−4) in those treated with FA only. Participants with these rare variants had a 2 mg/dL increase in HDL-C and 39 mg/dL decrease in TG as compared to 6.2 mg/dL increase in HDL-C and 100 mg/dL decrease in TG in those without these variants. Rare variants in the APOC-III gene were associated with a modest 3 mg/dL less reduction in APOB (P = 8.72 × 10−4) in those receiving FA and statin. ConclusionIn individuals with mixed dyslipidemia rare synonymous variants within LPL gene were associated with attenuated response to FA therapy while APOCIII rare variants were associated with a modest effect on APOB response to FA-statin therapy. These results should be replicated in a similar clinical trial for further confirmation.

Interaction between SNPs in the RXRA and near ANGPTL3 gene region inhibits apoB reduction after statin-fenofibric acid therapy in individuals with mixed dyslipidemia

The mixed dyslipidemia phenotype is characterized by elevated triglycerides (TG), low HDL cholesterol (HDL-C), increased ApoB levels, and premature coronary atherosclerosis. Fibrate-statin combination therapy reduces ApoB levels and coronary events in the mixed dyslipidemia population. We sought to identify gene-gene interactions that affect ApoB response to statin-fenofibric acid therapy in the mixed dyslipidemia population. Using a predefined subset of single-nucleotide polymorphisms (SNPs) that were previously associated with TG, VLDL, or HDL-C, we applied gene-gene interaction testing in a randomized, double-blind, clinical trial examining the response to fenofibric acid (FNA) and its combination with statin in 1,865 individuals with mixed dyslipidemia. Of 11,783 possible SNP pairs examined, we detected a single significant interaction between rs12130333, located within the ANGPTL3 gene region, and rs4240705, within the RXRA gene, on ApoB reduction after statin-FNA therapy (P = 4.0 × 10(-6)). ApoB response to therapy gradually reduced with the increasing number of T alleles in the rs12130333 but only in the presence of the GG genotype of rs4240705. Individuals doubly homozygous for the minor alleles at rs12130333 and rs4240705 showed a paradoxical increase of 1.8% in ApoB levels after FNA-statin combination therapy. No gene-gene interaction was identified other than an interaction between SNPs in the ANGPTL3 and RXRA regions, which results in the inhibition of ApoB reduction in response to statin-FNA therapy. Further study is required to examine the clinical applicability of this genetic interaction and its effect on coronary events.

Clinical Impact of Non-High Density Lipoprotein-Cholesterol and Apolipoprotein B on Clinical Outcomes in Metabolic Syndrome Patients With Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Background and ObjectivesNon-high density lipoprotein-cholesterol (non-HDL-C) and apolipoprotein B (ApoB) are markers of atherosclerotic risk and predictors of cardiovascular events. The aim of this study was to evaluate clinical impact of non-HDL-C and ApoB on clinical outcomes in metabolic syndrome (MS) patients with acute myocardial infarction (AMI) undergoing percuatneous coronary intervetion.Subjects and MethodsWe analyzed 470 MS patients (64.4±12.0 years, 53.6% male) with AMI who were followed-up for 12-month after percutaneous coronary intervention (PCI) from December 2005 to January 2008 in a single center. These patients were divided into 2 groups based on median values of non-HDL-C and ApoB. We studied their baseline and follow-up relation with 12-month clinical outcomes, all-cause death and major adverse cardiac events (MACE).ResultsMean values of baseline non-HDL-C and ApoB were 141.2±43.1 mg/dL and 99.3±29.0 mg/dL respectively. During 12-month follow-up 32 MACE (6.8%) and 12 deaths (2.5%) occurred. We observed significant correlation between non-HDL-C and ApoB. Twelve-month MACE and all-cause death after PCI showed no significant relation as non-HDL-C or ApoB levels increased. Follow-up patients (n=306, rate 65%) also did not show significant relation with clinical outcomes. Twelve-month MACE decreased as non-HDL-C and ApoB reduction rates increased.ConclusionThere was no significant association between higher non-HDL-C or ApoB and 12-month clinical outcomes in MS patients with AMI undergoing PCI. ApoB was found to be a better predictor of 12-month MACE than non-HDL-C based on their reduction rates.

Efficacy of apolipoprotein B synthesis inhibition in subjects with mild-to-moderate hyperlipidaemia

Mipomersen, an apolipoprotein (apo) B synthesis inhibitor, has been shown to produce potent reductions in apoB and LDL-cholesterol levels in animal models as well as healthy human volunteers. A randomized, double-blind, placebo-controlled, dose-escalation study was designed to evaluate the efficacy and safety of mipomersen monotherapy with or without dose loading in subjects with mild-to-moderate hyperlipidaemia. Fifty subjects with LDL-cholesterol levels between 119 and 266 mg/dL were enrolled into five cohorts at a 4:1 randomization ratio of active to placebo. Two 13-week dose regimens were evaluated at doses ranging from 50 to 400 mg/week. Mipomersen produced dose-dependent reductions in all apoB containing lipoproteins. In the 200 and 300 mg/week dose cohorts, mean reductions from baseline in LDL cholesterol were -45 ± 10% (P= 0.000) and -61 ± 8% (P= 0.000), corresponding to a -46 ± 11% (P= 0.000) and -61 ± 7% (P= 0.000) decrease in apoB levels. Triglyceride levels were also lowered with median reductions up to 53% (P= 0.021). The most common adverse events were injection site reactions. Seven of 40 subjects (18%) showed consecutive transaminase elevations >3× upper limit of normal. Five of these subjects received 400 mg/week, four of whom had apoB levels below the limit of detection. As a consequence, the 400 mg/week cohort was discontinued. Mipomersen administered as monotherapy in subjects with mild-to-moderate hyperlipidaemia produced potent reductions in all apoB-containing lipoproteins. Higher doses were associated with hepatic transaminase increases.

Major role of apolipoprotein B in cycloheximide‐induced acute hepatic steatosis in mice

Hepatic steatosis accompanied by impaired protein synthesis is often observed in hepatic dysfunction. To assess whether protein synthesis inhibition directly induces hepatic steatosis, we investigated the molecular mechanisms of cycloheximide (CHX)-induced fatty liver mice. C57/BL6CR mice were i.p. administrated CHX (20 mg/kg) three times every 4 h to induce hepatic steatosis. Hepatic lipid secretion, fatty acid oxidation, hepatic lipogenesis and hepatic lipid uptake were evaluated. Twenty-four hours after the first CHX injection, hepatic lipid levels increased in CHX-treated mice to 1.8-fold of that in controls but returned to normal within 48 h. The hepatic triglyceride (TG) secretion rate decreased significantly to 22% of controls, and the apolipoprotein B (apoB) protein level, but not microsomal TG transfer protein, decreased in CHX-treated mice. The apob gene expression was not significantly different between controls and CHX-treated mice. On the other hand, plasma free fatty acid and lipogenic protein levels did not increase and plasma β-hydroxybutyrate level remained stable, suggesting that the coordinated balance between fatty acid oxidation, hepatic lipid uptake and lipogenesis was not disrupted in this model. Cellular lipid accumulation and decreased cellular and secreted apoB were also observed in CHX-treated HepG2 cells. Knockdown of apoB in HepG2 cells also resulted in the cellular TG accumulation. We demonstrated that decreased hepatic lipid secretion due to acute apoB reduction is involved in the pathogenesis of CHX-induced liver steatosis.