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Non-high-density lipoprotein and very-low-density lipoprotein cholesterol and their risk predictive values in coronary heart disease.

To determine if non-high-density lipoprotein (HDL) cholesterol is a more useful predictor of coronary heart disease (CHD) risk than low-density lipoprotein (LDL) cholesterol and if very-low-density lipoprotein (VLDL) cholesterol is an independent predictor of CHD risk, data from the Framingham Heart Study (2,693 men, 3,101 women) were used for this analysis. All subjects were aged > or =30 years and free of CHD at baseline, and incident CHD was the end point (618 men, 372 women). Cox proportional-hazards models were used to assess the risk for CHD (relative risks and 95% confidence intervals) on the basis of the joint distribution of LDL cholesterol and non-HDL cholesterol (in milligrams per deciliter), as well as LDL cholesterol, non-HDL cholesterol, and VLDL cholesterol as continuous variables. After multivariate adjustment, within non-HDL cholesterol level, no association was found between LDL cholesterol and the risk for CHD, whereas within LDL cholesterol levels, a strong positive and graded association between non-HDL cholesterol and risk for CHD was observed. When the analysis was repeated within triglyceride levels (<200 vs > or =200 mg/dl), the risk pattern did not change significantly. Also, VLDL cholesterol was found to be a significant predictor of CHD risk after adjusting for LDL cholesterol at triglyceride levels of > or =200 or <200 mg/dl. In conclusion, these results suggest that non-HDL cholesterol level is a stronger predictor of CHD risk than LDL cholesterol; that is, VLDL cholesterol may play a critical role in the development of CHD.

Adult↗

Effects of heparin-mediated extracorporeal low-density lipoprotein precipitation beyond lowering proatherogenic lipoproteins--reduction of circulating proinflammatory and procoagulatory markers.

In addition to hypercholesterolemia, proinflammatory and prothrombotic markers have been suggested to play an important role in atherogenesis. We examined whether heparin-mediated extracorporeal low-density lipoprotein precipitation (HELP) therapy modulates the circulating levels of proinflammatory and prothrombotic markers. Twenty-two coronary heart disease (CHD) patients undergoing regular HELP-apheresis (18 males, 4 females, mean age 57.3 +/- 10.9 years) were enrolled in this study. A single HELP therapy treatment significantly decreased the circulating levels of high sensitivity C-reactive protein (hs-CRP), soluble vascular adhesion molecule-1 (sVCAM-1), soluble E-selectin, lipopolysaccharide binding protein (LBP), endothelin-1 (ET-1), and monocyte chemoattractant protein-1 (MCP-1) on average by 67, 37, 24, 27, 24, and 15%, respectively. Prothrombotic factors including fibrinogen, tissue factor (TF), soluble CD40 ligand (sCD40L), and homocysteine were decreased by 66, 27, 16, and 22%, respectively. In accordance with previous studies HELP therapy reduced total cholesterol, low density lipoprotein (LDL) cholesterol, and Lp(a) mass by 50, 61, and 62%, respectively. Our data suggest that simultaneous reduction of proinflammatory and prothrombotic factors together with atherogenic lipoproteins by HELP-apheresis may contribute to improvement of endothelial dysfunction and thereby inhibit progression of atherosclerotic lesions and stabilize the existing plaque.

Arteriosclerosis↗

Effect of low-density lipoprotein receptor mutation on lipoproteins and cardiovascular disease risk: a parent-offspring study.

Studies on the clinical consequences of different low-density lipoprotein (LDL) receptor genotypes in adult patients have yielded conflicting results. We hypothesized that children with familial hypercholesterolemia (FH) provide a better model to perform genotype-phenotype analyses than adults. We tested this hypothesis and assessed the effect of LDL receptor genotypes on lipoprotein levels and on parental risk of cardiovascular disease (CVD) in a pediatric FH cohort. We identified 75 different LDL receptor mutations in 645 children with heterozygous FH; in these children, null alleles were clearly associated with more elevated LDL cholesterol levels compared to receptor-defective mutations. Familial factors explained 50.4% of the variation in LDL cholesterol levels of this pediatric cohort compared to only 9.5% in adults. Parental CVD risk was not significantly different between carriers of null alleles and receptor-defective mutations (RR, 1.22; 95% CI, 0.76-1.95; p=0.4). The N543H/2393del9 mutation was associated with a less deteriorated lipid profile and the parents had less often CVD relative to parents with other mutations (RR, 0.39; 95% CI, 0.20-0.78; p=0.008). We could confirm that children with FH provide a better model to perform genotype-phenotype analyses. In particular, children with null alleles had significantly more elevated LDL cholesterol levels than carriers of other alleles but this was not associated with higher risk of CVD in the parents. Nonetheless, a specific LDL receptor mutation was associated with less deteriorated lipoprotein levels and a milder CVD risk.

Adolescent↗

ApoB-100 carrying lipoprotein, but not apoB-48, is the major subset of proatherogenic remnant-like lipoprotein particles detected in plasma of sudden cardiac death cases.

We have previously reported that plasma levels of remnant-like lipoprotein particles (RLP) significantly increased in sudden cardiac death cases with and without coronary atherosclerosis. In this study we have elucidated the major subset of proatherogenic RLP, containing both apoB-48 and apoB-100-carrying remnants, in plasma of SCD and control death cases. One hundred and sixty seven Japanese cases of sudden cardiac death and 78 cases of control death underwent autopsy within 12h after death were studied. Heart weight was 9.2% higher in SCD cases than controls (P<0.05). Moreover 57.5% or 96/167 of the cases had more than grade (2+) coronary atherosclerosis versus 21.8% or 17 of 78 controls (P<0.01). Approximately 2/3 of the cases had full stomach, reflecting the postprandial state at the time of death. Plasma TC, TG, VLDL-C, LDL-C were significantly elevated (P<0.001) together with RLP-C (P<0.01), RLP-TG (P<0.005) in SCD cases. Plasma RLP-apoB-100 levels were significantly elevated in SCD (P<-0.001), but apoB-48 levels were not. The median ratio of apoB-100/apoB-48 in RLP was 7.1 in SCD. The median RLP-TG/RLP-C ratio was 4.7, which suggested a large VLDL size. When apoB-48 and apoB-100 in RLP were divided into two groups, above and below the median level, respectively, apoB-48 inversely correlated with RLP-C (P<0.05) and RLP-TG (P<0.01), while apoB-100 in RLP positively correlated with RLP-C (P<0.01) in SCD cases. In conclusion, these results indicated that apoB-100 carrying lipoproteins, not apoB-48 carrying lipoproteins, were the major subset of RLP associated with sudden cardiac death in the postprandial state, regardless to the severity of coronary atherosclerosis.

Adult↗

Serum adiponectin is associated with high-density lipoprotein cholesterol, triglycerides, and low-density lipoprotein particle size in young healthy men.

The chromosomal localization of adiponectin has been found to be mapped to human chromosome 1q21.4-1q23, a region that was identified as a susceptibility locus for familial combined hyperlipidemia and polygenic type 2 diabetes. As these 2 disorders are associated with low high-density lipoprotein (HDL)-cholesterol, high triglycerides, and insulin resistance (IR), we examined the relation of serum adiponectin concentrations to serum lipid and lipoprotein profiles as well as IR in young healthy men. Serum adiponectin levels were positively associated with HDL-cholesterol, apolipoprotein (apo) A1, and low-density lipoprotein (LDL) particle size, and negatively associated with triglycerides and apo B. Negative associations were also found between adiponectin and body mass index (BMI), percent body fat, and IR,as determined by homeostasis model assessment (HOMA). However, after adjustment for BMI, no significant associations were found between adiponectin and LDL particle size and apo B. In a multiple regression analysis including all variables that showed significant univariate associations with adiponectin, associations of adiponectin with HDL-cholesterol (beta = 0.079, P =.0009), percent body fat (beta = -0.165, P =.002), and serum leptin (beta = -0.291, P =.01) were statistically significant. HDL-cholesterol (beta = 0.077, P =.001), percent body fat (beta = -0.078, P =.03), and LDL size (beta = 0.092, P =.03) emerged as significant and independent determinants of adiponectin after HOMA IR, fasting glucose, triglycerides, and systolic blood pressure (BP) were taken into account. Together, these variables explained 19% of adiponectin variability in the 2 models. HOMA IR did not emerge as a determinant of adiponectin in both models. These findings suggest that in young healthy men hypoadiponectinemia is more closely related to adiposity and dyslipidemia than IR.

Adiponectin↗

Low-density lipoprotein particle size, triglycerides, and high-density lipoprotein cholesterol as risk factors for coronary heart disease in older Japanese-American men.

Decreased low-density lipoprotein (LDL) particle size is associated with coronary heart disease (CHD) risk among middle-aged Caucasian populations, and has been consistently correlated with increased plasma levels of triglyceride and decreased levels of high-density lipoprotein (HDL) cholesterol. This study examines whether these risk factors predict CHD among older Japanese-American men. With use of the Honolulu Heart Program Lipoprotein Exam 3 (1980 to 1982) as baseline, and 12-year follow-up for CHD events, a nested, case-control study was designed. One hundred forty-five incident CHD cases were identified and matched to 2 controls each. LDL particle diameter (size) was determined by gradient gel electrophoresis. A 10-angstrom (A) decrease in LDL size at baseline was associated with increased risk of incident CHD (relative risk 1.28, 95% confidence interval 1.01 to 1.63). After adjustment for baseline risk factors, the LDL size association was no longer statistically significant (relative risk 1.13, 95% confidence interval 0.86 to 1.49). When principal components analysis was used to define a composite variable for LDL size, triglycerides, and HDL cholesterol, this component predicted CHD independent of smoking, alcohol consumption, physical activity, body mass index, hypertension, diabetes, and beta-blocker use (p <0.01). Therefore, this prospective analysis of data from older, Japanese-American men demonstrated that decreased LDL size is a univariate predictor of incident CHD, and that a composite risk factor of LDL size, triglyceride, and HDL cholesterol was a risk factor for CHD independent of other risk factors.

Aged↗

Relation of lipoprotein(a) as coronary risk factor to type 2 diabetes mellitus and low-density lipoprotein cholesterol in patients > or =65 years of age (The Italian Longitudinal Study on Aging).

High levels of serum lipoprotein(a) [Lp(a)] have been associated with increased risk of coronary artery disease (CAD), but this association apparently is not confirmed in elderly people. We evaluated the interactions of Lp(a) with lipid and nonlipid CAD risk factors in a sample of subjects enrolled in the prevalence survey (1992 to 1993) of the Italian Longitudinal Study on Aging (ILSA). The entire population consisted of 5,632 elderly people, aged 65 to 84 years, randomly selected in 8 Italian municipalities. The present cross-sectional study included 400 free-living elderly subjects (74 +/- 6 years) from the randomized cohort of Casamassima (Bari, Southern Italy) (n = 704). The results showed that in the elderly population, high serum Lp(a) is a CAD risk factor dependent on type 2 diabetes mellitus and elevated low-density lipoprotein (LDL) cholesterol levels. In particular, the combined effect of high Lp(a) (> or =20 mg/dl) and high LDL cholesterol (> or =3.63 mmol/L [> or =140 mg/dl]), increases coronary risk by 2.75 (95% confidence interval 7.70 to 0.99); finally, the effect of Lp(a) > or =20 mg/dl and LDL cholesterol > or =3.63 mmol/L (> or =140 mg/dl), combined with type 2 diabetes mellitus, increases risk of CAD by 6.65 (95% confidence interval 35.40 to 1.25). In the elderly, elevated Lp(a) levels appear not to be an independent predictor of CAD, but this lipoprotein is a risk factor only in subjects with type 2 diabetes mellitus and elevated LDL cholesterol.

Aged↗

Sex and time differences in the associations of non-high-density lipoprotein cholesterol versus other lipid and lipoprotein factors in the prediction of cardiovascular death (The Rancho Bernardo Study).

Non-high-density lipoprotein (HDL) cholesterol (total cholesterol [TC] minus HDL cholesterol) has been suggested as the preferred lipid fraction to predict cardiovascular disease. We compared the ability of lipids, lipoproteins, the ratio of total to HDL cholesterol (TC/HDL), and non-HDL cholesterol to predict fatal coronary heart disease (CHD) and cardiovascular disease in 1,386 women and 1,094 men (mean age 69 years). After 10 years, there were more deaths in men (n = 310) than women (n = 268), but the proportions of deaths attributed to CHD (23% and 25%, respectively) and cardiovascular disease (48% and 47%) were similar. In men, age-adjusted values for non-HDL cholesterol, TC/HDL ratio, and triglycerides each predicted a significantly increased risk of CHD and cardiovascular disease; none of these associations was independent of pack-years of smoking, systolic blood pressure, fasting plasma glucose, body mass index, and physical activity. In women, age-adjusted non-HDL cholesterol levels did not predict CHD or cardiovascular disease events before or after adjusting for these covariates and for estrogen replacement therapy. In women, only the ratio of TC to HDL cholesterol predicted CHD and cardiovascular disease deaths independent of estrogen use and other risk factors. Observed associations were sensitive to time, being evident in women at 3 and 5 years, and lost thereafter, but not apparent before 10 years in men. Thus, non-HDL cholesterol is not superior to individual lipids, lipoproteins, or their ratios in the prediction of cardiovascular death in older adults.

Aged↗

Mechanized lipoprotein(a) assay as a marker for coronary artery disease illustrates the usefulness of high lipoprotein(a) levels.

Only a few simple lipoprotein(a) [Lp(a)] assays are available in kit form for use in clinical laboratories. The present study compares the analytical and clinical performance of a mechanized immunonephelometric method to enzyme-linked immunosorbent assay. Clinical performance was evaluated by measuring lipoprotein markers in 191 patients, with the extent of stenosis defined by angiography. Analytically, both methods showed little or no correlation with cholesterol, high density lipoprotein cholesterol, elevated triglycerides, apo A-I and apo B, while they showed good agreement with one another (r = 0.88). The methods showed comparable well known differences between black and white persons. Logistic regression indicated that Lp(a) was a weak but independent marker for coronary artery disease (CAD). Receiver operator characteristic curve analysis showed an association with CAD only at higher Lp(a) concentrations. We conclude that Lp(a) at higher concentrations may be a contributory marker for CAD and that mechanized nephelometric assays for it can be used in the clinical laboratory.

Adult↗

Kinetics of triglyceride rich lipoproteins: chylomicrons and very low density lipoproteins.

Lipoprotein dynamics are complex during the postprandial state. A significant rise in chylomicron concentration is associated with increased competition for LPL with VLDL particles. This results in an increased concentration of large VLDL. The concentration of small VLDL is reduced as a result of diminished conversion of large to small VLDL. Such changes, induced in the postprandial state, complicate the application and development of models that describe lipoprotein particle kinetics. The development of models that integrate chylomicron and VLDL particle information, rather than surrogate markers, together with data including other variables will provide insight into the complexity of lipoprotein metabolism in the postprandial state.

Animals↗

Lipoprotein lipase gene mutations, plasma lipid levels, progression/regression of coronary atherosclerosis, response to therapy, and future clinical events. Lipoproteins and Coronary Atherosclerosis Study.

Mutations in human lipoprotein lipase (LPL) gene are potential risk factors for susceptibility to coronary artery disease (CAD). The objectives of this study were to determine the influence LPL mutations Asn291Ser and Ser447Ter on plasma lipid levels, regression and progression of CAD, clinical events rate, and response to fluvastatin therapy in the Lipoprotein and Coronary Atherosclerosis Study (LCAS) population. LCAS is a double blind, randomized, placebo-controlled study designed to test the influence of fluvastatin on progression or regression of CAD. The Asn291Ser and Ser447Ter genotypes were determined by polymerase chain reaction (PCR) and restriction enzyme digestion. Fasting plasma lipid profiles were measured and quantitative coronary angiography was performed at baseline and 2.5 years following randomization. Fatal and non-fatal cardiovascular events during the follow-up period were recorded. A total of 4% (14/363) and 18% (62/352) of the subjects had the Asn291Ser and Ser447Ter mutations, respectively. Overall, there was no statistically association between the Asn291Ser and Ser447Ter mutations and the baseline or final mean plasma levels of lipids, number of coronary lesions, total occlusions, the mean minimal lumen diameter (MLD) stenoses and the clinical events rate. However, patients with the Ser447Ter variant had a slightly higher baseline high density lipoprotein-cholesterol (HDL-C) level (46.2 +/- 12 vs 43.2 +/- 11, P = 0.057), less increase in plasma HDL levels in response to fluvastatin therapy (3 vs 11%, P = 0.056) and a higher cardiovascular events rate (23 vs 13%, P = 0.056). Thus, the Ser447Ter variant had a modest influence on plasma HDL levels and the rate of cardiovascular events. These changes were of borderline statistical significance. Neither the Ser447Ter nor the Asn291Ser mutation had a major impact on susceptibility to CAD, progression or regression of CAD, clinical events rate or response to fluvastatin therapy in LCAS population.

Adult↗

Quantification of lipoprotein(a) and apolipoprotein(a) in plasma and lipoprotein fractions in the hypertriglyceridemic state.

Lipoprotein(a) [Lp(a)] is a risk factor for coronary heart disease (CHD) in particular in association with high low density lipoprotein (LDL) cholesterol concentrations. Hypertriglyceridemia on the other hand has been found to be associated with low Lp(a) values. This observation could be confirmed in 851 patients of the outpatient lipid clinic. Lp(a) median levels were 2.7-fold higher in patients with triglycerides below 200 mg/dl as compared with patients expressing triglyceride levels above 200 mg/dl (19 vs 7 mg/dl, P < 0.0001). In contrast to these data apolipoprotein(a) [apo(a)] has been detected in triglyceride-rich lipoproteins (TRL). To find out whether the presence of apo(a) in TRL is determined by the concentration of these particles, apo(a) concentrations were measured in TRL in fasting plasma of ten hypertriglyceridemic patients and ten normal controls with Lp(a) serum levels above 25 mg/dl. The apo(a) concentration in TRL did not show statistically significant differences between controls and patients (2.0+/-0.9 vs 1.8+/-1.6 mg/dl). In the second part of the study apo(a) levels in TRL were measured before and after fat feeding in eight healthy volunteers. Again no significant differences were observed in the apo(a) concentrations of the d < 1.006 a ml fraction before and after fat feeding (1.03+/-1.06 vs 0.81+/-0.63 mg/dl). In summary, this study fails to show an association of apo(a) with TRL for different states of hypertriglyceridemia. This negative finding is shown for constant particle numbers but might not be true if the particle number in TRL increases.

Apolipoproteins A↗

Family history of early cardiovascular disease in children with moderate to severe hypercholesterolemia: relationship to lipoprotein (a) and low-density lipoprotein cholesterol levels.

Lipoprotein (a) (Lp(a)) is an established cardiovascular risk factor in adults. We sought to evaluate whether raised Lp(a) levels were predictive of a family history of early cardiovascular disease (CVD) in children already at increased risk for premature atherosclerosis because of elevated low-density lipoprotein (LDL) cholesterol levels. Lp(a) and serum lipid levels were measured in 69 children and offspring with established moderate to severe hypercholesterolemia (serum cholesterol > 170 mg/dL) who were aged 10.7 +/- 4.3 years (range 1.5 to 21 years) and had been referred to a pediatric lipid center. The children represented families with a positive (n = 27) or negative (n = 42) history for premature CVD (<55 years of age in parent or grandparent). In all children, Lp(a) levels ranged from 1 to 140 mg/dL, with a median of 29 mg/dL. Mean total cholesterol, LDL cholesterol, and high-density lipoprotein (HDL) cholesterol levels were 234 mg/dL, 166 mg/dL, and 45 mg/dL, respectively. There was no difference in median Lp(a) levels between the children with a positive family history and those with a negative family history (29.9 mg/dL vs 29.0 mg/dL, respectively). In contrast, children with a positive family history showed significantly higher LDL cholesterol levels (186 +/- 61 mg/dL vs 153 +/- 52 mg/dL, P = .02). Thus, in this group of hypercholesterolemic children, LDL cholesterol but not Lp(a) levels were associated with a family history of premature CVD. Further studies are needed to identify additional specific risk factors associated with the development of CVD in this population.

Adolescent↗

The effect of growth hormone on low-density lipoprotein cholesterol and lipoprotein (a) levels in familial hypercholesterolemia.

Severe elevations of low-density lipoprotein (LDL) cholesterol are not always normalized with conventional drugs. Growth hormone decreases LDL cholesterol levels, in part by augmenting liver LDL receptor activity. This increase may be on the order of magnitude of the increase induced by statins. We investigated the effect of growth hormone in familial hypercholesterolemia (FH) in a randomized, double-blind, placebo-controlled study. Thirty-one men with FH aged 20 to 48 years, of whom 81% had a known LDL receptor gene mutation, discontinued all lipid-lowering drugs 6 weeks before the study. Dietary stabilization continued for 5 more weeks, followed by single-blind placebo injections for 1 week. Thereafter, 16 subjects were allocated to recombinant growth hormone 0.05 IU/kg/d and 15 to placebo injected subcutaneously for 12 weeks. Baseline lipid levels were similar in both groups. One subject in the growth hormone group withdrew after 8 weeks due to shoulder pain. Mean compliance among the rest of the subjects was 98%. The mean change in LDL cholesterol was -0.46 mmol/L (95% confidence interval [CI], -1.00 to 0.09 mmol/L) in the growth hormone group versus 0.08 mmol/L (95% CI, -0.55 to 0.71 mmol/L) in the placebo group (difference not significant). No changes occurred in the levels of other lipids, lipoprotein particles, or apolipoproteins, with the exception of lipoprotein(a) [Lp(a)]. The median changes in Lp(a) were 33% (interquartile range, 2% to 53%) and -15% (interquartile range, -22% to 18%) in the growth hormone and placebo groups, respectively (P = .02). We conclude that the effect of growth hormone on LDL cholesterol levels in FH is less than expected, based on its LDL-catabolic effects, and is counteracted by profound increases in Lp(a) levels, resulting in unchanged levels of apolipoprotein B. Thus, growth hormone is probably not useful as adjunctive therapy in FH.

Adult↗

Decrease in plasma low-density lipoprotein cholesterol, apolipoprotein B, cholesteryl ester transfer protein, and oxidized low-density lipoprotein by plant stanol ester-containing spread: a randomized, placebo-controlled trial.

OBJECTIVE: The ester of plant stanols significantly reduces plasma levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in Western people. Effects of plant stanol ester-containing spread on plasma levels of TC, LDL-C, and apolipoprotein B (apoB) were studied in a randomized, placebo-controlled trial in Japanese subjects whose diet is low in fat and cholesterol. The effects of plant stanol ester on plasma levels of arteriosclerosis-promoting factors, namely remnants of triacylglycerol (TG)-rich lipoproteins, cholesteryl ester transfer protein (CETP), and oxidized LDL (Ox-LDL), were also studied. The assessment of safety was also made. METHODS: One hundred and five healthy volunteers were assigned randomly to one of three groups: placebo spread (n = 35), 2 g/d of plant stanol (3.4 g of stanol ester; n = 34), and 3 g/d of plant stanol (5.1 g of stanol ester; n = 36). Plasma levels of lipids were measured at start of the study, at 2 and 4 wk (end of trial), and at 8 wk (+4 wk). Plasma apoproteins, cholesterol in remnant-like particles which are equivalent to remnants of TG-rich lipoproteins (RLP-C), CETP mass, and Ox-LDL were measured at the beginning and the end of the trial. Plasma levels of plant steroids and fat-soluble vitamins were also measured for the assessment of safety. RESULTS: Background and dietary composition did not differ among groups. Plasma levels of TC, LDL-C, apoB, apoE, CETP mass, and Ox-LDL were reduced significantly by 6.5%, 9.6%, 8.3%, 4.5%, 6.1%, and 20%, respectively, in the 2 g/d plant stanol group. Plasma levels of TC, LDL-C, apoB, CETP mass, and Ox-LDL were decreased significantly by 5.5%, 7.3%, 5.6%, 3.3%, and 19%, respectively, in the 3 g/d plant stanol group. Plasma levels of plant stanols, plant sterols, retinol, beta-carotene, and alpha-tocopherol did not change in any group, but levels of campestanol increased and alpha-tocopherol decreased slightly in the sitostanol groups. CONCLUSION: Plasma levels of TC and LDL-C were significantly reduced by the plant stanol ester-containing spread. The smaller reduction than in Western studies and the lack of dose dependency in this study might be due to the different basal diets. We concluded that plant stanol ester-containing spread is efficacious in reducing plasma LDL-C, apoB, CETP, and Ox-LDL and that 2 g/d plant stanol is adequate for Japanese people. No significant side effects were observed in any group.

Apolipoproteins B↗

Physical activity modulates the effect of a lipoprotein lipase mutation (D9N) on plasma lipids and lipoproteins.

We investigated interactions between a mutation (D9N) in the lipoprotein lipase (LPL) gene and physical activity, as well as other lifestyle factors, on lipid traits in a population-based sample of Dutch men and women (n = 379). We used questionnaire information to classify physical activity, alcohol consumption, and smoking habits, while overweight was defined as a body mass index (BMI) > 25 kg/m2. Non-fasting blood samples were used for the determination of lipid traits and the D9N genotype. Fifteen subjects (4%) carried the mutation. They presented with higher levels of total cholesterol, apolipoprotein (apo) B and triglycerides compared to non-carriers. While no interactions with overweight, alcohol consumption, and smoking were found, a strong interaction between the D9N mutation and physical activity became apparent. Physically inactive D9N carriers (n = 5) had considerably higher total cholesterol (+2 mmol/l, p < or = 0.0001) and apo B levels (+63 mg/dl, p < or = 0.0001) compared to non-carriers of this mutation, whereas their high-density lipoprotein (HDL)-cholesterol concentrations were lower (-0.22 mmol/l, p < 0.05). This was not the case for physically active D9N carriers (n = 10). In conclusion, a common variant of the LPL gene (D9N) adversely affects plasma lipid and lipoprotein profiles. However, the unfavorable consequences may be counteracted by physical activity.

Adult↗

Effects of oleic acid on the biosynthesis of lipoprotein apoproteins and distribution into the very-low-density lipoprotein by the isolated perfused rat liver.

The effects of oleic acid on the biosynthesis and secretion of VLDL (very-low-density-lipoprotein) apoproteins and lipids were investigated in isolated perfused rat liver. Protein synthesis was measured by the incorporation of L-[4,5-3H]leucine into the VLDL apoproteins (d less than 1.006) and into apolipoproteins of the whole perfusate (d less than 1.21). Oleate did not affect incorporation of [3H]leucine into total-perfusate or hepatic protein. The infusion of oleate, however, increased the mass and radioactivity of the VLDL apoprotein in proportion to the concentration of oleate infused. Uptake of oleate was similar with livers from fed or fasted animals. Fasting itself (24 h) decreased the net secretion and incorporation of [3H]leucine into total VLDL apoprotein and decreased the output of VLDL protein by the liver. A linear relationship existed between the output of VLDL triacylglycerol (mumol/h per g of liver) and secretion and/or synthesis of VLDL protein. Net output of VLDL cholesterol and phospholipid also increased linearly with VLDL-triacylglycerol output. Oleate stimulated incorporation of [3H]leucine into VLDL apo (apolipoprotein) E and apo C by livers from fed animals, and into VLDL apo Bh, B1, E and C by livers from fasted rats. The incorporation of [3H]leucine into individual apolipoproteins of the total perfusate lipoprotein (d less than 1.210 ultracentrifugal fraction) was not changed significantly by oleate during perfusion of livers from fed rats, suggesting that the synthesis de novo of each apolipoprotein was not stimulated by oleate. This is in contrast with that observed with livers from fasted rats, in which the synthesis of the total-perfusate lipoprotein (d less than 1.210 fraction) apo B, E and C was apparently stimulated by oleate. The observations with livers from fed rats suggest redistribution of radioactive apolipoproteins to the VLDL during or after the process of secretion, rather than an increase of apoprotein synthesis de novo. It appears, however, that the biosynthesis of apo B1, Bh, E and C was stimulated by oleic acid in livers from fasted rats. Since the incorporations of [3H]leucine into the VLDL and total-perfusate apolipoproteins were increased in fasted-rat liver when the fatty acid was infused, part of the apparent stimulated synthesis of the VLDL apoprotein may be in response to the increased formation and secretion of VLDL lipid.

Animals↗

Is vitellogenin an ancestor of apolipoprotein B-100 of human low-density lipoprotein and human lipoprotein lipase?

Vitellogenin, an ancient animal protein, is the major yolk protein of eggs, where it is used as a food source during embryogenesis. Here it is shown that vitellogenins, including those from the invertebrates Caenorhabditis elegans and Drosophila melanogaster, contain domains that are homologous with parts of apolipoprotein B-100 (apoB-100) of human low-density lipoprotein and human lipoprotein lipase. As vitellogenins are likely to have been used by invertebrates during embryogenesis well before the circulation of lipids appeared in vertebrates, it is suggested that copies of a precursor gene, serving a function similar to vitellogenin, were modified to code for part of apoB-100 and lipoprotein lipase in vertebrates. In addition to providing a link between invertebrates and vertebrates for proteins involved in lipid transport, these homologies suggest new functions for vitellogenin other than being a yolk food for the developing embryo.

Amino Acid Sequence↗