ApoA-I/A-II-HDL positively associates with apoB-lipoproteins as a potential atherogenic indicator.

BACKGROUND: We recently reported distinct nature of high-density lipoproteins (HDL) subgroup particles with apolipoprotein (apo) A-I but not apoA-II (LpAI) and HDL having both (LpAI:AII) based on the data from 314 Japanese. While plasma HDL level almost exclusively depends on concentration of LpAI having 3 to 4 apoA-I molecules, LpAI:AII appeared with almost constant concentration regardless of plasma HDL levels having stable structure with two apoA-I and one disulfide-dimeric apoA-II molecules (Sci. Rep. 6; 31,532, 2016). The aim of this study is further characterization of LpAI:AII with respect to its role in atherogenesis. METHODS: Association of LpAI, LpAI:AII and other HDL parameters with apoB-lipoprotein parameters was analyzed among the cohort data above. RESULTS: ApoA-I in LpAI negatively correlated with the apoB-lipoprotein parameters such as apoB, triglyceride, nonHDL-cholesterol, and nonHDL-cholesterol + triglyceride, which are apparently reflected in the relations of the total HDL parameters to apoB-lipoproteins. In contrast, apoA-I in LpAI:AII and apoA-II positively correlated to the apoB-lipoprotein parameters even within their small range of variation. These relationships are independent of sex, but may slightly be influenced by the activity-related CETP mutations. CONCLUSIONS: The study suggested that LpAI:AII is an atherogenic indicator rather than antiatherogenic. These sub-fractions of HDL are to be evaluated separately for estimating atherogenic risk of the patients.

Bioinformatic Analysis of Plasma Apolipoproteins A-I and A-II Revealed Unique Features of A-I/A-II HDL Particles in Human Plasma.

Plasma concentration of apoA-I, apoA-II and apoA-II-unassociated apoA-I was analyzed in 314 Japanese subjects (177 males and 137 females), including one (male) homozygote and 37 (20 males and 17 females) heterozygotes of genetic CETP deficiency. ApoA-I unassociated with apoA-II markedly and linearly increased with HDL-cholesterol, while apoA-II increased only very slightly and the ratio of apoA-II-associated apoA-I to apoA-II stayed constant at 2 in molar ratio throughout the increase of HDL-cholesterol, among the wild type and heterozygous CETP deficiency. Thus, overall HDL concentration almost exclusively depends on HDL with apoA-I without apoA-II (LpAI) while concentration of HDL containing apoA-I and apoA-II (LpAI:AII) is constant having a fixed molar ratio of 2 : 1 regardless of total HDL and apoA-I concentration. Distribution of apoA-I between LpAI and LpAI:AII is consistent with a model of statistical partitioning regardless of sex and CETP genotype. The analysis also indicated that LpA-I accommodates on average 4 apoA-I molecules and has a clearance rate indistinguishable from LpAI:AII. Independent evidence indicated LpAI:A-II has a diameter 20% smaller than LpAI, consistent with a model having two apoA-I and one apoA-II. The functional contribution of these particles is to be investigated.

Sequential change in physicochemical properties of LDL during oxidative modification.

Oxidized LDL is thought to be a highly atherogenic lipoprotein. Structural background of this pathogenesis, however, has not yet been well defined. Physicochemical characterization of this lipoprotein is still controversial, which therefore makes it difficult to take a mechanistic approach to its atherogenicity. We thus conducted investigation of time-dependent changes in chemical compositions and alternation of physical properties of LDL in detail during its oxidation induced by human embryonic endothelial cells and copper ions. The oxidation caused hydrolysis of glycerolipids being demonstrated as decrease of triglyceride and choline-phospholipid and increase of lysophosphatidylcholine. Fragmentation of apoB was also induced while over-all protein components stayed with the particles. The density of the particles continuously shifted to higher fractions for all the particles to reach d ≥ 1.044 after 10h incubation. The average diameter of LDL, however, decreased from 28.1 nm to 25.6 nm by 5h and increased to 27.1 nm towards 20 h incubation with the increase of discoid particles. These dynamic changes can be interpreted by losing fatty acyl group from the core lipid components perhaps due to oxidative degradation and by increase of surface lysophosphatidylcholine to cause remodeling of the particles.

Genetic variants of the fatty acid desaturase gene cluster are associated with plasma LDL cholesterol levels in Japanese males.

Fatty acid (FA) compositions in tissues are related to metabolic disorders, and consequently the appropriate management of underlying FA compositions in tissues is considered to be important. However, the relationship among the serum lipid profiles, the FA composition of the red blood cell (RBC) membranes and genetic variations in the fatty acid desaturase (FADS) genes in Japanese men is unclear. In this study, the subjects recruited were 137 Japanese men, 40 to 60 y old, who had a regular health checkup. Their serum lipid profile and the relative FA composition of the RBC membranes were measured. They were genotyped for the single nucleotide polymorphisms (SNPs) rs174553, rs174546, rs99780 and rs174583 in FADS gene. Multiple regression analysis was conducted to detect the relationship among hyperlipidemia, the FA composition of the RBC and the FADS genotypes. As a result, the homozygous genotype for the minor alleles in rs174553, rs174546, rs99780 were found to be associated with lower low-density lipoprotein cholesterol (LDL-C) levels and a lower LDL-C/total-cholesterol ratio. The homozygous genotype for the minor alleles reduced the risk of high LDL-C level (R2=0.50, ß=-0.20, p=0.009), whereas, the arachidonic acid (AA) levels in the carriers of the homozygous genotype for the minor alleles tended to be lower compared with the carriers of the major alleles. However, no significant differences were observed in any FA level among the three genotypes for four SNPs. These results indicate that the appropriate management of serum LDL-C levels depending on genetic predisposition in FADS genotypes should be encouraged.

Potential use of cholesterol lipoprotein profile to confirm obesity status in dogs.

A common sign of obesity, in dogs, is hyperlipidemia, which is characterized by hypercholesterolemia and/or hypertriglycemia. Hyperlipidemia can be caused by a quantitative increase in circulating lipoproteins (LP) or by a higher lipid concentration in the various LP classes. In this study, we sought to determine whether aberrations occur with cholesterol lipoprotein profile, especially with sub HDL-cholesterol fraction % in obese dogs. Using clinically healthy and disease free (no overt signs) body condition score classified obese dogs, of all ages, we attempted to determine the influence of age, gender and obesity status on cholesterol lipoprotein profiling. Overall, no aberration in pattern was observed in obese dogs <8 years of age. However, in older obese animals (≥8 years of age), the general aberration pattern to cholesterol lipoprotein observed was that a significant decrease in HDL2 and 3 fraction % occurs with a concomitant increase in either HDL1-Cho or VLDL and LDL -Cho fraction % depending on gender. Linear regression analysis indicated that obesity status appears to significantly affect total cholesterol, HDL2 and 3-Cho, VLDL and LDL-Cho levels (P=0.02, 0.046, and 0.045, respectively), whereas it is borderline with HDL1-Cho (P=0.062). On the other hand, age significantly influenced TG, Total cholesterol, and HDL1-Cho levels (P=0.009, 0.006, and 0.002, respectively), while gender influenced VLDL and LDL-Cho (P=0.024) level. Therefore, aberrations in cholesterol lipoprotein profile pattern might be of potential use to assess and diagnose obesity status, in conjunction with BCS, especially of older overweight animals which might be considered borderline obese.

Association of lifestyle factors, polymorphisms in adiponectin, perilipin and hormone sensitive lipase, and clinical markers in Japanese males.

According to recent genome-wide association studies, a number of single nucleotide polymorphisms is reported to be associated with diseases or several clinical markers. Among them, adiponectin (ADIPOQ) and perilipin (PLIN) polymorphisms are major factors of obesity. However, the association between lifestyle factor, these polymorphisms and obesity-related clinical markers in Japanese is not well researched. Therefore, the aim of present study is to investigate the association between lifestyle factor, polymorphisms of lipid metabolic genes, and clinical markers in 148 middle-aged Japanese males. The study revealed that ADIPOQ 45 T>G and ADIPOQ 276 G>T genotypes were significantly associated with triglyceride, total cholesterol, hemoglobin A1c (HbA1c) in blood and body mass index (BMI). PLIN4 11482 G>A and hormone sensitive lipase (LIPE)-60 C>G genotypes were respectively associated with BMI and serum triglyceride. Not only genetic factors but also lifestyle factors influence several clinical markers. The BMI of subjects who like sweets and have the GG allele in ADIPOQ 276 G>T was higher than that of subjects who don't like sweets. The habit of eating fruits and fish affected low-density lipoprotein-cholesterol of the GT allele and HbA1c of the TT allele in ADIPOQ 276 G>T. Those findings indicate improvement and conservation of lifestyle depending on genetic predisposition in ADIPOQ, PLIN and LIPE should be encouraged.

Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-cholesterol concentrations in humans.

BACKGROUND: Cocoa powder is rich in polyphenols such as catechins and procyanidins and has been shown in various models to inhibit LDL oxidation and atherogenesis. OBJECTIVE: We examined whether long-term intake of cocoa powder alters plasma lipid profiles in normocholesterolemic and mildly hypercholesterolemic human subjects. DESIGN: Twenty-five subjects were randomly assigned to ingest either 12 g sugar/d (control group) or 26 g cocoa powder and 12 g sugar/d (cocoa group) for 12 wk. Blood samples were collected before the study and 12 wk after intake of the test drinks. Plasma lipids, LDL oxidative susceptibility, and urinary oxidative stress markers were measured. RESULTS: At 12 wk, we measured a 9% prolongation from baseline levels in the lag time of LDL oxidation in the cocoa group. This prolongation in the cocoa group was significantly greater than the reduction measured in the control group (-13%). A significantly greater increase in plasma HDL cholesterol (24%) was observed in the cocoa group than in the control group (5%). A negative correlation was observed between plasma concentrations of HDL cholesterol and oxidized LDL. At 12 wk, there was a 24% reduction in dityrosine from baseline concentrations in the cocoa group. This reduction in the cocoa group was significantly greater than the reduction in the control group (-1%). CONCLUSION: It is possible that increases in HDL-cholesterol concentrations may contribute to the suppression of LDL oxidation and that polyphenolic substances derived from cocoa powder may contribute to an elevation in HDL cholesterol.

Effects of bezafibrate on lipoprotein subclasses and inflammatory markers in patients with hypertriglyceridemia--a nuclear magnetic resonance study.

BACKGROUND: Hypertriglyceridemia is often associated with elevated remnants, small dense LDL and decreased HDL-cholesterol (C). The objective of this study was to investigate the efficacy of bezafibrate on lipoprotein subfractions profile and inflammation markers in patients with hypertriglyceridemia. METHODS: Twenty-four hypertriglyceridemic subjects took bezafibrate, 400 mg daily, for 4 weeks. Lipoprotein subclasses were measured by nuclear magnetic resonance (NMR) spectroscopy. Inflammation markers including C-reactive protein (CRP), interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) were also determined. RESULTS: Bezafibrate lowered triglyceride (TG) by 59% and increased HDL-C by 20%. NMR analysis revealed that bezafibrate lowered large TG-rich lipoproteins and IDL by 81% and 46%, respectively. Small LDL was selectively decreased by 53% with increase in large to intermediate LDL, thus altering the LDL distribution towards the larger particles (mean diameter 19.9 to 20.7 nm, p = 0.0001). Small (HDL1) and intermediate (HDL3) HDL significantly increased by 168% and 70%, whereby resulting in a significant reduction of the mean HDL particle size from 9.0 to 8.7 nm (p = 0.026). None of inflammation makers showed significant change by bezafibrate. CONCLUSIONS: Bezafibrate effectively ameliorates atherogenic dyslipidemia by reducing remnants and small LDL as well as by increasing HDL particles in hypertriglyceridemic subjects.

Fenofibrate effectively reduces remnants, and small dense LDL, and increases HDL particle number in hypertriglyceridemic men - a nuclear magnetic resonance study.

Hypertriglyceridemia is often associated with small dense low density lipoprotein (LDL), elevated remnants, and decreased high density lipoprotein (HDL)-cholesterol (C), which comprise the dyslipidemic triad. The objective of this study was to investigate the effect of fenofibrate on the lipoprotein subfraction profile and inflammation markers in hypertriglyceridemic men. Twenty hypertriglyceridemic men were administered fenofibrate, 200 mg daily, for 8 weeks. Lipoprotein subclasses were measured by nuclear magnetic resonance (NMR) spectroscopy. Inflammation markers including C-reactive protein (CRP), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1) were also determined. Fenofibrate lowered triglyceride (TG) by 58% and increased HDL-C by 18%. NMR analysis revealed that very low density lipoprotein (VLDL), particularly large VLDL, intermediate density lipoprotein (IDL), and small LDL, were significantly decreased, and LDL distribution shifted towards the larger particles. HDL distribution was altered; there was an increase in small HDL and a decrease in large HDL, resulting in a significant decrease in HDL particle size, from 9.1 to 8.9 nm, as well as a 27% increase in HDL particle number. Among inflammation markers, CRP was significantly decreased by 42%. In conclusion, fenofibrate effectively improves atherogenic dyslipidemia by reducing remnants and small LDL, as well as by increasing HDL particles. These effects, together with the favorable effect on inflammation, might provide a clinical benefit in hypertriglyceridemic subjects.

Serum fatty acids, lipoprotein (a) and apolipoprotein profiles of middle-aged men and women in South Vietnam.

In Vietnam, increasing fat consumption is a trend recognized recently in urban areas. To obtain a reasonable nutrition status and prevent cardiovascular disease (CVD), it is necessary to obtain information on habitual fat intake and biochemical parameters as risk factors for CVD in Vietnamese populations. Therefore, from the analysis of serum fatty acid composition, fat consumption patterns in Vietnamese populations in South Vietnam, with different incomes, are discussed in this study. In addition, some risk factors for premature CVD, serum lipoprotein (a) and apolipoprotein concentrations are also assessed in these Vietnamese populations. The study was carried out in men and women aged 40-59 in three different districts: urban (n = 100), suburban (n = 98) and rural (n = 98). The results of serum fatty acid composition analysis reflected differences in quality fat intake among the three populations. The urban population was estimated to consume more vegetable oil but less fish than their rural counterparts. Although serum lipoprotein (a) and apolipoprotein B levels were below the ranges associated with atherogenesis, ongoing attention to dietary fat intake for the prevention of CVD in Vietnamese populations is required.