Attenuation of atherogenic apo B-48-dependent hyperlipidemia and high density lipoprotein remodeling induced by vitamin C and E combination and their beneficial effect on lethal ischemic heart disease in mice

BACKGROUND AND AIMS: Atherosclerotic cardiovascular disease is highly prevalent and its underlying pathogenesis involves dyslipidemia including pro-atherogenic high density lipoprotein (HDL) remodeling. Vitamins C and E have been proposed as atheroprotective agents for cardiovascular disease management. However, their effects and benefits on high density lipoprotein function and remodeling are unknown. In this study, we evaluated the role of vitamin C and E on non HDL lipoproteins as well as HDL function and remodeling, along with their effects on inflammation/ oxidation biomarkers and atherosclerosis in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice. METHODS AND RESULTS: Mice were pre-treated for 5 weeks before and during atherogenic diet feeding with vitamin C and E added to water and diet, respectively. Compared to a control group, combined vitamin C and E administration reduced serum total cholesterol and triglyceride levels by decreasing apo B-48-containing lipoproteins, remodeled HDL particles by reducing phospholipid as well as increasing PON1 and apo D content, and diminished PLTP activity and levels. Vitamin supplementation improved HDL antioxidant function and lowered serum TNF-α levels. Vitamin C and E combination attenuated atherogenesis and increased lifespan in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice. CONCLUSIONS: Vitamin C and E administration showed significant lipid metabolism regulating effects, including HDL remodeling and decreased levels of apoB-containing lipoproteins, in mice. In addition, this vitamin supplementation generated a cardioprotective effect in a murine model of severe and lethal atherosclerotic ischemic heart disease.

Korean pine nut oil replacement decreases intestinal lipid uptake while improves hepatic lipid metabolism in mice

BACKGROUND/OBJECTIVES: Consumption of pine nut oil (PNO) was shown to reduce weight gain and attenuate hepatic steatosis in mice fed a high-fat diet (HFD). The aim of this study was to examine the effects of PNO on both intestinal and hepatic lipid metabolism in mice fed control or HFD. MATERIALS/METHODS: Five-week-old C57BL/6 mice were fed control diets containing 10% energy fat from either Soybean Oil (SBO) or PNO, or HFD containing 15% energy fat from lard and 30% energy fat from SBO or PNO for 12 weeks. Expression of genes related to intestinal fatty acid (FA) uptake and channeling (Cd36, Fatp4, Acsl5, Acbp), intestinal chylomicron synthesis (Mtp, ApoB48, ApoA4), hepatic lipid uptake and channeling (Lrp1, Fatp5, Acsl1, Acbp), hepatic triacylglycerol (TAG) lipolysis and FA oxidation (Atgl, Cpt1a, Acadl, Ehhadh, Acaa1), as well as very low-density lipoprotein (VLDL) assembly (ApoB100) were determined by real-time PCR. RESULTS: In intestine, significantly lower Cd36 mRNA expression (P < 0.05) and a tendency of lower ApoA4 mRNA levels (P = 0.07) was observed in PNO-fed mice, indicating that PNO consumption may decrease intestinal FA uptake and chylomicron assembly. PNO consumption tended to result in higher hepatic mRNA levels of Atgl (P = 0.08) and Cpt1a (P = 0.05). Significantly higher hepatic mRNA levels of Acadl and ApoB100 were detected in mice fed PNO diet (P < 0.05). These results suggest that PNO could increase hepatic TAG metabolism; mitochondrial fatty acid oxidation and VLDL assembly. CONCLUSIONS: PNO replacement in the diet might function in prevention of excessive lipid uptake by intestine and improve hepatic lipid metabolism in both control diet and HFD fed mice.

Effect of Pitavastatin Treatment on ApoB-48 and Lp-PLA2 in Patients with Metabolic Syndrome: Substudy of PROspective Comparative Clinical Study Evaluating the Efficacy and Safety of PITavastatin in Patients with Metabolic Syndrome

BACKGROUND: Apolipoprotein (Apo) B-48 is an intestinally derived lipoprotein that is expected to be a marker for cardiovascular disease (CVD). Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a vascular-specific inflammatory marker and important risk predictor of CVD. The aim of this study was to explore the effect of pitavastatin treatment and life style modification (LSM) on ApoB-48 and Lp-PLA2 levels in metabolic syndrome (MS) patients at relatively low risk for CVD, as a sub-analysis of a previous multi-center prospective study. METHODS: We enrolled 75 patients with MS from the PROPIT study and randomized them into two treatment groups: 2 mg pitavastatin daily+intensive LSM or intensive LSM only. We measured the change of lipid profiles, ApoB-48 and Lp-PLA2 for 48 weeks. RESULTS: Total cholesterol, low density lipoprotein cholesterol, non-high density lipoprotein cholesterol, and ApoB-100/A1 ratio were significantly improved in the pitavastatin+LSM group compared to the LSM only group (P≤0.001). Pitavastatin+LSM did not change the level of ApoB-48 in subjects overall, but the level of ApoB-48 was significantly lower in the higher mean baseline value group of ApoB-48. The change in Lp-PLA2 was not significant after intervention in either group after treatment with pitavastatin for 1 year. CONCLUSION: Pitavastatin treatment and LSM significantly improved lipid profiles, ApoB-100/A1 ratio, and reduced ApoB-48 levels in the higher mean baseline value group of ApoB-48, but did not significantly alter the Lp-PLA2 levels.

The impact of lipid-metabolizing genetic polymorphisms on body mass index and their interactions with soybean food intake: a study in a Chinese population / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To evaluate the association of known polymorphisms in the lipid metabolic pathway with body mass index (BMI), and estimate their interactions with soybean food intake.</p><p><b>METHODS</b>A community-based cross-sectional survey was conducted in a Chinese Han population. BMI, soybean food intake, and single nucleotide polymorphisms of rs599839, rs3846662, rs3846663, rs12916, rs174547, rs174570, rs4938303, and rs1558861 were measured in 944 subjects. A multivariate logistic regression was used to analyze the association of the studied polymorphisms with BMIs. The expectation-maximization algorithm was employed to evaluate the extent of linkage disequilibrium between pairwise polymorphisms. The gene-environment interaction was assessed in the general multifactor dimensionality reduction model.</p><p><b>RESULTS</b>The polymorphisms of rs3846662 and rs3846663 were associated with 10% highest BMIs when comparing to the 10% lowest values both in individuals and haplotype-based association tests. Although no statistically significant gene-environment interactions were found, people with the haplotype composed of C allele in rs3846662 and T allele in rs3846663 and low frequency of soybean intake had significantly higher risk to overweight and obesity as compared with those with the haplotype consisting of T allele in rs3846662 and C allele in rs3846663 and highly frequent soybean food intake, with an odds ratio of 1.64 (95% confidence interval: 1.15-2.34, P<0.01) after adjusting for the common confounders.</p><p><b>CONCLUSION</b>Our study has suggested that rs3846662 and rs3846663 may be the potential candidate polymorphisms for obesity, and their effect on the pathogenesis could be mediated by the frequency of soybean food intake.</p>

Investigation of the assembly of chylomicrons in hamster enterocytes using pluronic-L81 acid as a probe

A major function of the enterocytes is absorption, processing, and export of dietary lipids into the lymphatic system. Pluronic L-81 is a non-ionic hydrophobic surfactant, which specifically inhibits lipid absorption in the intestine when administered in vivo. This compound is therefore an attractive probe to perturb and investigate the molecular and intracellular events in chylomicron assembly in the enterocytes. In the present study pluronic acid was administered to hamsters followed by isolation of the enterocytes and cell fractionation to investigate the effect of pluronic acid on intracellular events in lipid absorption. Four types of diet were administered to hamsters for three weeks; low-fat chow, high-fat chow and each diet with or without added pluronic acid. Sub-cellular fractions of freshly isolated enterocytes were prepared. Consistent with morphological observation, the high fat diet resulted in a three-fold increase in the triacylglycerol [TAG] content of the enterocytes and addition of pluronic acid to either the low fat or the high fat diets resulted in a ten-fold increase in cellular TAG levels. Determination of the mass of TAG and the time course of incorporation of 3H-triolein, administered by gavage, showed that the increased TAG was recovered in the microsomal [endoplasmic reticulum] fraction and the cytosol. In microsomes, increased TAG was recovered mainly in the membrane although there was a significant amount in the microsomal luminal contents. Pluronic acid therefore acts at the level of the endoplasmic reticulum and inhibits the assembly of apo-B48 with chylomicron TAG. The excess TAG is transferred to cytosolic stores

Effect of Omega-3 Fatty Acids on Low Density Lipoprotein Subfraction, Adiponectin and Apolipoprotein B in Type 2 Diabetic Patients

BACKGROUND: Omega-3 fatty acids derived from fish oil have been reported to exert a beneficial effect on reducing cardiovascular disease. Reports about their mechanism have generated several interesting findings, including a change in small dense low density lipoprotein (sdLDL) cholesterol proportion, adiponectin, and apolipoprotein B (apoB), in addition to changes in the lipid profile. The principal objective of our study was to evaluate the effects of omega-3 fatty acids on plasma sdLDL, adiponectin, apoB100, and B48 in type 2 diabetic patients with hypertriglyceridemia. METHODS: We randomized 28 type 2 diabetic patients in a placebo-controlled, double-blind trial to receive either omega-3 fatty acids or placebo, both administered at a dose of 4 g daily for 12 weeks. LDL subfractions prior to and after treatment were separated via low-speed ultracentrifugation and analyzed via immunoelectrophoresis. Adiponectin, apoB100, and B48 levels were measured using an ELISA kit. RESULTS: sdLDL proportions were reduced in the omega-3 fatty acids group by 11% after 12 weeks of treatment (n = 17, P = 0.001), and were reduced by 4% in the control group (n = 11, P = 0.096). The patients receiving the omega-3 fatty acids evidenced a significant reduction in the levels of triglyceride (P = 0.001), apoB100, and B48 after 12 weeks (P = 0.038 and P = 0.009, respectively) relative to the baseline. Omega-3 fatty acids supplementation increased fasting blood glucose (P = 0.011), but the levels of HbA1c in each group did not change to a statistically significance degree. The adiponectin value was not reduced in the omega-3 fatty acids group (P = 0.133); by way of contrast, the placebo group evidenced a significant reduction in adiponectin value after 12 weeks (P = 0.002). CONCLUSION: Omega-3 fatty acid treatment proved effective in the reduction of atherogenic sdLDL and apoB in type 2 diabetic patients (Clinical trials reg. no. NCT 00758927, clinicaltrials.gov).