Triglycerides: a risk factor for coronary heart disease

Local Condiment, Iru, Obtained from the Fermentation of Parkia biglobosa Seed Substantially Reduced the Serum Cholesterol Level of Wister Rats

Hypercholesterolaemia is one of the risk factors in coronary heart disease. Hence, this research was designed to investigate the effect of iru on cholesterol levels in hypercholesterolaemic rats. The fermented condiment iru was produced naturally and with starter cultures of Lactobacillus plantarum, Bacillus subtilis, and Leuconostoc sp.. The hypercholesterolaemic rats were fed a diet supplemented with iru for 28 days, and total cholesterol, triglyceride (TG), high density lipoproteins (HDL), and low density lipoproteins (LDL) were determined before and after feeding. Cholesterol levels in hypercholesterolaemic rats (100.80 mg/dL) were reduced to 56.99∼80.21 mg/dL after feeding with iru supplementation while rats not placed on the iru diet had cholesterol levels of 119 mg/dL. There were also significant reductions (P<0.05) in serum TG (78.77∼32.57 mg/dL) and LDL (28.43∼6.63 mg/dL) levels in rats fed the iru diet compared with the control (63.36 mg/dL). Higher and significantly different (P<0.05) HDL was found in rats fed with iru fermented with L. plantarum (44.01 mg/dL) while the least was found in the untreated group (28.93 mg/dL). The results from this study suggest that supplementing the diet with iru obtained by the fermentation of Parkia biglobosa seeds may significantly reduce cholesterol level in the blood stream.

Effects of Cabbage-Apple Juice Fermented by Lactobacillus plantarum EM on Lipid Profile Improvement and Obesity Amelioration in Rats

This study aimed to investigate the potential of cabbage-apple juice, fermented by Lactobacillus plantarum EM isolated from kimchi, to protect against obesity and dyslipidemia that are induced by a high-fat diet in a rat model. Male rats were fed a modified AIN-93M high-fat diet (HFD), the same diet supplemented with non-fermented cabbage-apple juice, or the same diet supplemented with fermented cabbage-apple juice for eight weeks. In the HFD-fermented cabbage- apple juice administered groups the following parameters decreased: body weight, liver and white fat pad weights, serum triglyceride (TG), total cholesterol (TC), LDL-cholesterol, insulin, glucose and leptin levels, TG levels, while HDL-C and adiponectin levels in serum increased as compared with the HFD group. The HFD-fed rats that were supplemented with fermented cabbage-apple juice exhibited significantly lower fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and malic enzyme gene expression levels when compared to the exclusively HFD-fed rats. The anti-obesity and hypolipidemic effects were marginally greater in the fermented juice administered group than in the non-fermented juice administered group. These results suggest that cabbage-apple juice-especially fermented cabbage-apple juice-might have beneficial effects on lipid metabolism dysfunction and obesity-related abnormalities. However, further studies are necessary for analyzing the biochemical regulatory mechanisms of fermented juice for obesity amelioration and lipid metabolic homeostasis.

Antiobesity Effects of Extract from Spergularia marina Griseb in Adipocytes and High-Fat Diet-Induced Obese Rats

Obesity has recently risen and become a serious health concern in Korea according to the westernized diet and altered lifestyle. Hence, there is a growing interest in the supplementation of phytochemicals to find a safe and effective functional ingredient to treat obesity. Spergularia marina Griseb (SM) has traditionally been used as a natural herb against chronic diseases in Korea. In this study, we investigated the antiobesity effects of SM in vitro and in vivo. SM ethanol extract (SME) inhibited proliferation and differentiation in murine adipocytes and primary porcine pre-adipocytes in a dose-dependent manner. In the in vivo study, supplementation of SM powder (SMP) remarkably attenuated fat accumulation in HFD-induced obese rats. In addition, SMP supplementation improved lipid profiles in the serum and tissues of high-fat induced obese rats. Collectively, these data indicated that SME exhibited antiobesity effects by modulating adipogenesis and lipolysis. Furthermore, SMP could be developed as an obesity-induced metabolic syndrome treatment.

Impact of serum levels of lipoprotein lipase, hepatic lipase, and endothelial lipase on the progression of coronary artery disease

Purpose

The purpose of this study was to investigate the relationship between serum levels of lipoprotein lipase (LPL), hepatic lipase (HL), and endothelial lipase (EL) and the progression of coronary artery disease (CAD).

Materials and methods

According to the inclusion criteria, exclusion criteria, diagnostic criteria, angiography results, and the random matching scheme, the enrolled patients were divided into the following two groups: the progression-free group (n = 47) and the progression group (n = 15). The baseline characteristics and various biochemical parameters were obtained from the medical records and medical history. Serum LPL, HL, and EL levels were detected by ELISA. The correlation between serum LPL, HL, and EL levels and coronary lesions was statistically analyzed with SPSS software.

Results

Significant differences were observed in serum levels of HL and EL between the progression-free group and the progression group (HL, 75.5 ± 39.2 ng/mL vs. 125.1 ± 42.1 ng/mL, P < 0.05; EL, 139.2 ± 59.6 pg/mL vs. 175.1 ± 40.1 pg/mL, P < 0.05), while the difference in the LPL level was not significant (P > 0.05). Receiver operating characteristic curve (ROC) analysis showed that the area under the curve (AUC) values of LPL, HL, and EL were 0.506 (95% CI: 0.369–0.642, P = 0.9470), 0.792 (95% CI: 0.664–0.888, P < 0.0001), and 0.693 (95% CI: 0.553–0.811, P = 0.0095), respectively. Additionally, logistic regression analysis showed that the serum level of HL was an independent risk factor for coronary artery lesion progression.

Conclusion

Serum levels of EL and HL, but not the serum level of LPL, were positively correlated with the progression of CAD. The serum level of HL was an independent risk factor for the progression of CAD, while the serum level of EL or LPL was not an independent risk factor for the progression of CAD. For the diagnosis of CAD progression, the serum level of HL was better than the serum level of EL or LPL.

Interactions among genes involved in reverse cholesterol transport and in the response to environmental factors in dyslipidemia in subjects from the Xinjiang rural area

Gene-gene and gene-environment interactions may be partially responsible for dyslipidemia, but studies investigating interactions in the reverse cholesterol transport system (RCT) are limited. We explored these interactions in a Xinjiang rural population by genotyping five SNPs using SNPShot technique in APOA1, ABCA1, and LCAT, which are involved in the RCT (690 patients, 743 controls). We conducted unconditional logistical regression analysis to evaluate associations and generalized multifactor dimensionality reduction to evaluate interactions. Results revealed significant differences in rs670 and rs2292318 allele frequencies between cases and controls (P<0.025). rs670 G allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.315, OR 95% CI: 1.067–2.620; P = 0.010). rs2292318 T allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.264, OR 95% CI: 1.037–1.541; P = 0.020). Gene-gene interaction model APOA1rs670-ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166 (P = 0.0107) and gene-environment interaction model ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166-obesity-smoking were optimal dyslipidemia predictors (P = 0.0107) and can interact (4). Differences in A-C-A-C-A and G-G-G-T-G haplotype frequencies were observed (P<0.05). Serum lipid profiles could be partly attributed to RCT gene polymorphisms. Thus, dyslipidemia is influenced by APOA1, ABCA1, LCAT, environmental factors, and their interactions.

Omega-3 fatty acids supplementation improves endothelial function and arterial stiffness in hypertensive patients with hypertriglyceridemia and high cardiovascular risk

Association between hypertriglyceridemia and cardiovascular (CV) disease is still controversial. The purpose of this study was to compare omega-3 and ciprofibrate effects on the vascular structure and function in low and high CV risk hypertensive patients with hypertriglyceridemia. Twenty-nine adults with triglycerides 150-499 mg/dL were divided into low (<7.5%) and high (≥7.5%) CV risk, randomized to receive omega-3 fatty acids 1800 mg/d or ciprofibrate 100 mg/d for 12 weeks. Treatment was switched after 8-week washout. Clinical evaluation and vascular tests were assessed at baseline and after intervention. Peripheral (131 ± 3 to 125 ± 3 mm Hg, P < .05) and aortic (124 ± 3 to 118 ± 2 mg/dL, P < .05) systolic blood pressure were decreased by ciprofibrate in low-risk patients. In high-risk patients, pulse wave velocity was reduced (10.4 ± 0.4 to 9.4 ± 0.3 m/s, P < .05) and flow-mediated dilation was increased (11.1 ± 1.6 to 13.5 ± 1.2%, P < .05) by omega-3. In conclusion, omega-3 improved arterial stiffness and endothelial function, pointing out the beneficial effect of this therapy on vascular aging, in high-risk patients.

LC/MS-based polar metabolite profiling reveals gender differences in serum from patients with myocardial infarction

Myocardial infarction (MI), a leading cause of death worldwide, results from prolonged myocardial ischemia with necrosis of myocytes due to a blood supply obstruction to an area of the heart. Many studies have reported gender-related differences in the clinical features of MI, but the reasons for these differences remain unclear. In this study, we applied ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) and various statistical methods-such as multivariate, pathway, and correlation analyses-to identify gender-specific metabolic patterns in polar metabolites in serum from healthy individuals and patients with MI. Patients with diagnosed MI (n=68), and age- and body mass index-matched healthy individuals (n=68), were included in this study. The partial least-squares discriminant analysis (PLS-DA) model was generated from metabolic profiling data, and the score plots showed a significant gender-related difference in patients with MI. Many pathways were associated with amino acids and purines; amino acids, acylcarnitines, and purines differed significantly between male and female patients with MI. This approach could be utilized to observe gender-specific metabolic pattern differences between healthy controls and patients with MI.

Association between the MLX interacting protein-like, BUD13 homolog and zinc finger protein 259 gene polymorphisms and serum lipid levels

This study aimed to detect the association between the MLX interacting protein-like (MLXIPL), BUD13 homolog (BUD13) and zinc finger protein 259 (ZNF259) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese Mulao and Han populations. Genotyping of 9 SNPs was performed in 825 Mulao and 781 Han participants. The genotype and allele frequencies of ZNF259 rs2075290 and rs964184, and BUD13 rs10790162 SNPs were different between the Mulao and Han populations (P < 0.001). The SNPs of ZNF259 rs2075290 and BUD13 rs10790162 were associated with serum total cholesterol levels; ZNF259 rs2075290 and rs964184, BUD13 rs10790162, and MLXIPL rs3812316 and rs13235543 were associated with triglyceride (TG); and MLXIPL rs35332062 was associated with apolipoprotein (Apo) A1 in the Mulaos (P < 0.006–0.001). However, in the Hans, the SNPs of ZNF259 rs2075290 and BUD13 rs10790162 were associated with serum TG levels; ZNF259 rs2075290 was associated with low-density lipoprotein cholesterol and the ApoA1/ApoB ratio (P < 0.006–0.001). Significant linkage disequilibria were noted among ZNF259 rs2075290 and rs964184 and BUD13 rs10790162, and between MLXIPL rs3812316 and rs13235543 (r² > 0.05, P < 0.001). The haplotypes of A-C-G-A-C (rs2075290A-rs964184C-rs10790162G-rs17119975A-rs11556024C) and C-C-C-C (rs799161C-rs35332062C-rs3812316C-rs13235543C) accounted for over half of the % haplotype of each ethnic group.

Hypolipidemic activity of a natural mineral water rich in calcium, magnesium, and bicarbonate in hyperlipidemic adults

PURPOSE

This study compared the effects of a mineral water rich in calcium, magnesium, bicarbonate, and sulfate and a marketed mineral water with a composition similar to that of urban water on the lipid profile of dyslipidemic adults.

METHODS

In a randomized controlled trial, 32 adults received one liter of "rich mineral water" daily for one month, and 37 adults drank the same amount of normal mineral water for the same period. Changes in lipid profiles were compared separately in each studied group at the end of one month.

RESULTS

RESULTS showed that mean cholesterol and low density lipoprotein LDL levels were significantly decreased in both studied groups after one month of drinking mineral water (P<0.05); however, no significant differences in high density lipoprotein (HDL) and triglyceride (TG) levels were seen in either group one month after drinking. There were no statistically significant differences between the "rich mineral water" and the normal mineral water groups in any of the above-mentioned lipid levels ( P>0.05).

CONCLUSION

A one-month intake of mineral water rich in calcium, magnesium bicarbonate, and sulfate decreased cholesterol and LDL levels but not TG or HDL levels in dyslipidemic adults.

Fasting remnant lipoproteins can predict postprandial hyperlipidemia

BACKGROUND

Hypertriglyceridemia and postprandial hyperlipidemia is thought to play an important role in atherosclerosis, but to select patients at high-risk for cardiovascular diseases is difficult with triglycerides (TG) alone in these patients.

METHODS

To predict postprandial hyperlipidemia without inconvenient test meal loading, we examined lipid concentrations before and after test meal loading and fasting adiponectin, and investigated which of these other than TG were significant during the fasting period in 45 healthy individuals (men: women, 26:19).

RESULTS

TG, remnant-like particle-cholesterol and -triglyceride (RemL-C, RLP-C, and RLP-TG), and TG/apolipoprotein(apo)B were significantly elevated after loading and fasting values significantly and positively correlated with incremental area under the curve (iAUC) (r=0.80, r=0.79, r=0.63, r=0.58, r=0.54; p<0.0001). Fasting adiponectin positively correlated with fasting high-density lipoprotein-cholesterol (r=0.43, p<0.005) and apoA-I (r=0.34, p<0.05), and negatively correlated with iAUC of TG, RemL-C, RLP-C, RLP-TG, and TG/apoB (r=-0.37, r=-0.41, r=-0.37, r=-0.36, r=-0.37; p<0.05). We constructed the model of multivariable linear regression analysis without fasting TG. In the sex-, BMI-, age-, and waist circumference-adjusted analysis of postprandial TG elevation 2 h after test meal loading in all participants, RemL-C, RLP-C, RLP-TG, and TG/apoB were significant factors, but adiponectin was not.

CONCLUSION

Fasting triglyceride-rich lipoprotein-related values, especially RemL-C, RLP-C, RLP-TG, and TG/apoB are useful predictors of postprandial hyperlipidemia in young healthy individuals. Although fasting adiponectin concentration correlated with the iAUCs for TG, RemL-C, RLP-C, RLP-TG, and TG/apoB, it was not a significant predictor of postprandial hyperlipidemia in multivariable linear regression analysis.

The atherogenic dyslipidemia ratio [log(TG)/HDL-C] is associated with residual vascular risk, beta-cell function loss and microangiopathy in type 2 diabetes females

Background

Atherogenic dyslipidemia (AD), defined as low HDL-C plus elevated triglycerides (TG), comorbid to T2DM, increases cardiometabolic risk for CAD even when LDL-C is at target. In T2DM males, AD was shown to correlate with β-cell function loss, yet it is not established whether this applies across gender.

Aim

To establish the prevalence and severity of AD in T2DM females, and to determine how it relates to cardiometabolic phenotype, glucose homeostasis, micro- and macrovascular complications, and 10-year absolute CV risk (UKPDS Risk Engine).

Methods

340 T2DM females were ranked according to quintiles (Q) of the continuous variable log(TG)/HDL-C, with AD prevalence defined as HDL-C <50 mg.dL^-1 plus TG ≥150 mg.dL^-1, and β-cell function assessed with HOMA.

Results

AD prevalence was 35%; mean HDL-C and TG were 52 (15) and 160 (105) mg.dL^-1. AD was significantly related to central fat, metabolic syndrome, sedentarity and skeletal sarcopenia, as well as to _hsCRP, fibrinogen, uric acid, cystatin-C, Big ET-1, and 10-year UKPDS CV risk. AD correlated stepwise with lower β-cell function and hyperbolic product, and with accelerated loss of residual insulin secretion, higher HbA_1c and prevalent microangiopathy.

Conclusions

log(TG)/HDL-C is a simple means to grade AD and residual macrovascular risk in T2DM females. This ratio associates with major non-LDL cardiometabolic variables and ranks predicted CAD risk. In addition, log(TG)/HDL-C identifies worsening glucose homeostasis, poorer glycemic control, and prevalent microangiopathy.

Effect of hydroalcoholic extract of Hypericum perforatum on selected traditional and novel biochemical factors of cardiovascular diseases and atherosclerotic lesions in hypercholesterolemic rabbits: A comparison between the extract and lovastatin

Context:

Evidence suggests that diets with high contents of cholesterol will increase serum lipoproteins and apolipoproteins, thereby increase risk of atherosclerosis. According to literature, some plants show hypolipidemic, hypocholestrolemic, and antiatherosclerotic activities.

Aims:

In this study, antiatherosclerotic effect of Hypericum perforatum hydroalcoholic extract on hypercholesterolemic rabbits was compared with that of lovastatin.

Materials and Methods:

Twenty five mature male New Zealand rabbits were randomly divided into five groups of five and were fed for 60 days as follows: Standard diet (GroupI), standard diet and hydroalcoholic extract of Hypericum perforatum (150 mg/kg daily)(GroupII), standard diet, hydroalcoholic extract of Hypericum perforatum (150 mg/ kg daily) and cholesterol (1% of food content) (Group III), standard diet and cholesterol (1% of food content)(GroupIV), and finally standard diet, lovastatin (10 mg/kg), and cholesterol (1% of foodcontent) (GroupV).

Results:

Hypericum perforatum extract significantly decreased the levels of apolipoprotein B(apoB), apolipoprotein B/apolipoprotein A (apoB/apoA), triglyceride, cholesterol, low density lipoprotein cholesterol, oxidized LDL, malondialdehyde, and C-reactive protein (CRP) as well as atherosclerosis index, and increased high density lipoprotein and apoA in rabbits of Group III compared to the rabbits of Group IV. The effect of Hypericum perforatum extract in decreasing the level of some biochemical factors like apoB, apoB/apoA, and CRP was meaningfully more than that of lovastatin. Histopathological findings confirmed that hydroalcoholic extract of Hypericum perforatum restricted the atherosclerotic lesions.

Conclusions:

This study indicates that hydroalcoholic extract of Hypericum perforatum possesses hypolipidemic and anti-atherosclerotic effects and could be beneficial in the management of hyperlipidemia and atherosclerosis.

Reducing vascular events risk in patients with dyslipidaemia: an update for clinicians

Reducing the risk of vascular events in patients with dyslipidaemia requires cardiovascular disease risk stratification and lifestyle/pharmacological intervention on modifiable risk factors. Reduction of low-density lipoprotein cholesterol (LDL-C) with statins is highly effective in reducing cardiovascular disease in patients with and without diabetes, but leaves unaddressed a sizeable residual vascular risk (RvR), which is rarely quantified in routine clinical practice. Such RvR may relate to lack of strict target attainment for all atherogenic variables [LDL-C, non-high-density lipoprotein cholesterol (HDL-C) and/or apolipoprotein B(100)]. Another substantial lipid-related and modifiable RvR component is related to atherogenic dyslipidaemia, especially as global rates of obesity, type 2 diabetes and metabolic syndrome are increasing. Atherogenic dyslipidaemia is associated with insulin-stimulated very-low-density lipoprotein overproduction and reduced reverse cholesterol transport. The hallmark of atherogenic dyslipidaemia is the coexistence of low HDL-C and elevated triglycerides. Therapeutic lifestyle changes and combination lipid-lowering therapy with drugs targeting atherogenic dyslipidaemia (such as fibrates or innovative drugs targeting atherogenic dyslipidaemia and/or apolipoprotein B(100) metabolism) on top of background statins, have a potential to reduce RvR in high-risk groups, as shown in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, in which combination therapy with simvastatin plus fenofibrate decreased macrovascular risk in patients with diabetes and atherogenic dyslipidaemia, and retinopathy risk irrespective of baseline lipids.

Hepatic lipase, high density lipoproteins, and hypertriglyceridemia

Hepatic lipase (HL) is a lipolytic enzyme that contributes to the regulation of plasma triglyceride (TG) levels. Elevated TG levels may increase the risk of developing coronary heart disease, and studies suggest that mutations in the HL gene may be associated with elevated TG levels and increased risk of coronary heart disease. Hepatic lipase facilitates the clearance of TG from the very low density lipoprotein (VLDL) pool, and this function is governed by the composition and quality of high density lipoprotein (HDL) particles. In humans, HL is a liver resident enzyme regulated by factors that release it from the liver and activate it in the bloodstream. HDL regulates the release of HL from the liver and HDL structure controls HL transport and activation in the circulation. Alterations in HDL-apolipoprotein composition can perturb HL function by inhibiting the release and activation of the enzyme. HDL structure may therefore affect plasma TG levels and coronary heart disease risk.

Dyslipidaemia of obesity, metabolic syndrome and type 2 diabetes mellitus: the case for residual risk reduction after statin treatment

Dyslipidaemia is frequently present in obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM). The predominant features of dyslipidaemia in these disorders include increased flux of free fatty acids (FFA), raised triglyceride (TG) and low high density lipoprotein cholesterol (HDL-C) levels, a predominance of small, dense (atherogenic) low density lipoprotein cholesterol (LDL) particles and raised apolipoprotein (apo) B values Posprandial hyperlipidaemia may also be present. Insulin resistance (IR) appears to play an important role in the pathogenesis of dyslipidaemia in obesity, MetS and T2DM. The cornerstone of treatment of this IR-related dyslipidaemia is lifestyle changes and in diabetic patients, tight glycaemic control. In addition to these measures, recent clinical trials showed benefit with statin treatment. Nevertheless, a substantial percentage of patients treated with statins still experience vascular events. This residual vascular risk needs to be addressed. This review summarizes the effects of hypolipidaemic drug combinations (including statins with cholesterol ester protein inhibitors, niacin, fibrates or fish oil, as well as fibrate-ezetimibe combination) on the residual vascular risk in patients with obesity, MetS or T2DM.

The proprotein convertase subtilisin/kexin type 9 gene E670G polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

Background

Proprotein convertase subtilisin-like kexin type 9 (PCSK9) plays a key role in regulating plasma low-density lipoprotein cholesterol (LDL-C) levels. However, the association of E670G (rs505151) polymorphism in the PCSK9 gene and serum lipid levels is inconsistent in several previous studies. The present study was undertaken to detect the association of PCSK9 E670G polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations.

Methods

A total of 649 subjects of Bai Ku Yao and 646 participants of Han were randomly selected from our previous samples. Genotypes of the PCSK9 E670G polymorphism were determined via polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing.

Results

Serum levels of total cholesterol, high-density lipoprotein cholesterol (HDL-C), LDL-C, and apolipoprotein (Apo) AI were lower in Bai Ku Yao than in Han (P < 0.01 for all). The frequency of G allele was 2.00% in Bai Ku Yao and 4.80% in Han (P < 0.01). There was significant difference in the genotypic and allelic frequencies between Bai Ku Yao and Han (P < 0.01); between normal LDL-C (≤ 3.20 mmol/L) and high LDL-C subgroups (> 3.20 mmol/L, P < 0.01) in Bai Ku Yao; and between normal HDL-C (≥ 0.91 mmol/L) and low HDL-C (< 0.91 mmol/L, P < 0.05), between normal ApoAI (≥ 1.00 g/L) and low ApoAI (< 1.00 g/L, P < 0.05), or between normal ApoAI/ApoB ratio (≥ 1.00) and low ApoAI/ApoB ratio (< 1.00, P < 0.01) subgroups in Han. The G allele carriers in Han had higher serum HDL-C levels and the ratio of ApoAI to ApoB than the G allele noncarriers. The G allele carriers in Han had higher serum HDL-C and ApoAI levels than the G allele noncarriers in males (P < 0.05 for each), whereas the G allele carriers had lower serum ApoB levels and higher the ratio of ApoAI to ApoB than the G allele noncarriers in females (P < 0.05 for all). Serum HDL-C and ApoAI levels in Han were correlated with genotypes (P < 0.05) in males, and serum ApoB levels and the ratio of ApoAI to ApoB were associated with genotypes (P < 0.05) in females.

Conclusions

The PCSK9 E670G polymorphism is mainly associated with some serum lipid parameters in the Han population. The G allele carriers had higher serum HDL-C and ApoAI levels in males, and lower serum ApoB levels and higher the ApoAI/ApoB ratio in females than the G allele noncarriers.

log(TG)/HDL-C is related to both residual cardiometabolic risk and β-cell function loss in type 2 diabetes males

Background

T2DM is associated with atherogenic dyslipidemia (AD), defined as decreased HDL-C plus raised triglycerides (TG). AD confers increased risk for CAD, even when LDL-C is at target. AD is rarely assessed due to lack of screening methods consensus.

Aim

To establish the prevalence and severity of AD from log(TG)/HDL-C in T2DM males, and to determine how it relates to cardiometabolic phenotype, glucose homeostasis, micro- and macrovascular complications, and 10-year UKPDS CV risk.

Methods

585 T2DM males divided according to quintiles (Q) of log(TG)/HDL-C. AD prevalence defined as HDL-C <40 mg.dL^-1 plus TG ≥150 mg.dL^-1. β-cell function assessed with HOMA.

Results

Mean HDL-C and TG were 44 (13) and 204 (155) mg.dL^-1. AD prevalence was 35%. AD correlated with lower β-cell function, with accelerated loss of insulin secretion, and with poorer HbA_1c levels. AD was related to a high prevalence of CAD, and also to 10-year absolute CAD risk.

Conclusions

log(TG)/HDL-C is a simple means to estimate AD and the residual CV risk it confers in T2DM. AD closely associates with major cardiometabolic and glucose homeostasis determinants and poorer metabolic control. The ratio also relates to macroangiopathy prevalence and ranks future CAD risk, and is well-suited to capture non-LDL-related macrovascular residual risk and major glycemic determinants.

Different effects of 26-week dietary intake of rapeseed oil and soybean oil on plasma lipid levels, glucose-6-phosphate dehydrogenase activity and cyclooxygenase-2 expression in spontaneously hypertensive rats

We intended to determine whether or not dietary canola oil (CO) elevates plasma lipids and oxidative stress, since both of these are, possibly, related to the CO-induced life shortening through exacerbation of hypertension-associated vascular lesions found in stroke-prone spontaneously hypertensive rats (SHRSP). Spontaneously hypertensive rats (SHR) were used in this study to avoid a potential bias in the results due to the irregular death by stroke seen in SHRSP. SHR were fed for 26 weeks on a chow containing either, 10 wt/wt% of CO or soybean oil (SO), i.e., the control. Elevated plasma lipids and glucose-6-phosphate dehydrogenase (G6PD) activation in the liver and erythrocyte were found in SHR fed CO compared to that fed SO, while anti-oxidative enzymes other than G6PD were not activated. The CO diet brought about significant vascular lesions in the kidney, in which abundant cyclooxygenase-2 (COX-2) positive foci were immunochemically located in the juxtaglomerular apparatus. These results suggest that dietary CO induces a hyperlipidemic condition, in which G6PD may serve as an NADPH provider, and aggravates genetic diseases in SHR (also, probably, in SHRSP). The increased COX-2 expression indicates a role of renin-angiotensin-aldosterone system activation in the increased vascular lesions, whereas the effects of oxidative stress remain unclear.

Effect of hydroalcoholic extracts of Nasturtium officinale leaves on lipid profile in high-fat diet rats

AIM OF THE STUDY

Nasturtium officinale R. Br. (Brassicaceae) is used as a home remedy in Iran as a cardioprotective agent without any scientific background. In this investigation an attempt was made to study the effect of Nasturtium officinale hydroalcoholic extract (NOE) on serum lipid profile which is closely associated with many cardiovascular diseases.

MATERIALS AND METHODS

Accordingly, serum total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were among the parameters investigated. We also evaluated the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels as a measure of hepatic cell damages.

RESULTS

Intragastric administration of NOE (500 mg/kg body weight per day) to groups of hypercholesterolaemic rats for 10 days lowered their serum TC, TG and LDL-C by 34.2, 30.1, and 52.9%, respectively, while raised the serum HDL-C level by 27.0% after 10 days of treatments. Treatment with NOE reduced serum ALT and AST levels compared to high-fat diet groups.

CONCLUSIONS

Based on these data, it is concluded that the NOE has definite cardioprotective potential and these results constitute a valid scientific basis for consuming Nasturtium officinale for medicinal application.

Contribution of tomato phenolics to antioxidation and down-regulation of blood lipids

This study was performed to understand the characteristics and biological activities of phenolics in tomatoes and to examine the effect of tomato on the regulation of blood lipids. Tomatoes of both big and small sizes were used fresh, after blanching, or after blanching and heating. Moreover, a human clinical trial was conducted to examine plasma antioxidation, status of blood lipids, and phenolic responses after ingestion of fresh tomato, tomato juice, and a lycopene drink. The contents of tomato phenolics were increased by 34% for small tomato and by 23% for big tomato after treatment by blanching and heating at 100 degrees C for 30 min. Tomato phenolics showed fair antioxidant activity (57-71%) and also synergistically promoted the antioxidation (81-100%) of tomato carotenoids. In the human clinical study, total antioxidant capacity and phenolic contents in plasma were increased after administration of fresh tomato and tomato juice, but no significant difference was found for lycopene drink consumption. Triglyceride levels and low-density lipoprotein cholesterol were decreased after administration of fresh tomato and tomato juice, and high-density lipoprotein cholesterol was increased.

Hypolipidemic Effects of Biopolymers Extracted from Culture Broth, Mycelia, and Fruiting Bodies of Auricularia auricula-judae in Dietary-induced Hyperlipidemic Rats

Hypolipidemic effect of biopolymers extracted from culture broth (CP), mycelia (MP), and fruiting bodies (FP) of Auricularia auricula-judae was investigated in dietary-induced hyperlipidemic rats. The experimental animals were administrated (100 mg/kg body weight) with different biopolymers, daily for 4 weeks. Hypolipidemic effects were achieved in all the experimental groups, however, FP was proved to be the most potent one. The administration of the FP reduced the plasma triglyceride, total cholesterol, low-density lipoprotein cholesterol, and atherogenic index by 24.3, 28.5, 36.4, and 40.9%, respectively, while increased the high-density lipoprotein cholesterol level (9.0%), when compared to the saline (control) administered group.

Increase of neuronal histamine in obese rats is associated with decreases in body weight and plasma triglycerides

OBJECTIVE

The purpose of the present study was to examine the metabolic effects of a specific histamine H(3) receptor antagonist, the cinnamic amide NNC 0038-0000-1202 (NNC 38-1202).

RESEARCH METHODS AND PROCEDURES

Effects of NNC 38-1202 on paraventricular levels of histamine and acute effects on food intake were followed in normal rats, whereas effects on body weight homeostasis and lipid metabolism were studied in a rat model of diet-induced obesity (DIO).

RESULTS

NNC 38-1202, administered as single oral doses of 15 and 30 mg/kg, significantly (p < 0.01) increased paraventricular histamine by 339 +/- 54% and 403 +/- 105%, respectively, compared with basal levels. The same doses produced significant (p < 0.01) reductions in food intake. In DIO rats receiving NNC 38-1202 in a daily dose of 5 mg/kg for 22 days, a decrease in food intake was associated with a significant (p < 0.001) net loss of body weight (-11.0 +/- 4.8 grams), compared with rats receiving vehicle, which gained 13.6 +/- 3.0 grams. Also, NNC 38-1202 significantly (p < 0.05) reduced plasma triglycerides by approximately 42%, in parallel with increases in plasma free fatty acids and beta-hydroxybutyrate levels. Despite reductions in food intake and body weight following administration of NNC 38-1202, no sign of a decrease in energy expenditure was observed, and whole-body lipid oxidation was significantly (p < 0.05) increased in the period after dosing.

DISCUSSION

The present study suggests that antagonistic targeting of the histamine H(3) receptor decreases food intake, body weight, and plasma TG levels and, thus, represents an interesting approach to treatment of obesity and associated hyperlipidemia.

Effects of atorvastatin and apoA-I/phosphatidylcholine discs on triglyceride-rich lipoprotein subfractions as characterized by capillary isotachophoresis

BACKGROUND

The present study examined the effects of atorvastatin and the in vitro effect of apolipoprotein (apo) A-I/phosphatidylcholine (POPC) discs on charge-based triglyceride-rich lipoprotein (TRL) subfractions in a patient with type III hyperlipoproteinemia (HLP) and the apoE2/2 phenotype.

METHODS

Charge-based lipoprotein subfractions were characterized by capillary isotachophoresis (cITP). cITP analysis was performed using plasma that had been prestained with a lipophilic dye on a Beckman P/ACE MDQ system.

RESULTS

Treatment with atorvastatin for 4 weeks markedly decreased the slow (s)-migrating TRL subfraction and both fast- and slow-migrating low-density lipoprotein (LDL) subfractions, but did not affect the fast (f)-migrating TRL subfraction in this patient. ApoA-I/POPC discs consisted of two major charge-based subfractions that had the mobility of cITP fTRL and sTRL. Incubation of plasma from this patient in the presence of apoA-I/POPC discs caused not only a reduction in cITP fast- and intermediate-migrating HDL and an increase in cITP sHDL but also a reduction in fTRL and sTRL and an increase in sLDL.

CONCLUSION

Atorvastatin and apoA-I/POPC discs decreased cITP TRL subfractions in a complementary manner, suggesting that the combination of apoA-I/POPC discs and atorvastatin could be a promising therapeutic approach for hypertriglyceridemia.

Consistent Effects of Genes Involved in Reverse Cholesterol Transport on Plasma Lipid and Apolipoprotein Levels in CARDIA Participants

OBJECTIVE

To identify common variations in genes in the reverse cholesterol transport pathway with nongender-specific influence on plasma lipid and apolipoprotein levels.

METHODS AND RESULTS

An average of 5 single nucleotide polymorphisms (SNPs) were genotyped within each of 45 genomic regions (54 genes) in blacks (1131 females and 812 males) and whites (1102 females and 954 males) from the Coronary Artery Risk Development in Young Adults (CARDIA) study. SNPs and gene-based 3-SNP haplotypes were evaluated for their ability to predict variation in plasma apolipoproteins (apo) A-I and apoB, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides (TG). We identified 14 SNPs in 6 candidate gene regions that explained statistically significant variation in the same trait in both genders of at least one race and with evidence of consistent genotype mean trend across gender within race. Haplotype analyses identified 9 candidate gene regions that explained statistically significant variation in one or both races.

CONCLUSIONS

Four gene regions, ABCA1, APOA1/C3/A4/A5, APOE/C1/C4/C2, and CETP, explained plasma lipoprotein variation most consistently across strata. Other gene regions that influence plasma lipid and apolipoprotein levels within race include CYP7A1, LPL, PPARA, SOAT1, and SREBF2.

Differential effects of apolipoprotein E isoforms on lipolysis of very low-density lipoprotein triglycerides

Apolipoprotein (apo) E plays a key role in lipoprotein metabolism and has been proposed to modulate triglyceride (TG) lipolysis. However, no systematic investigation on lipolysis using all 3 isoforms of apoE has been performed. To clarify the role of common human apoE isoforms in the lipolysis of very low-density lipoprotein (VLDL) TGs, we overexpressed human apoE isoforms in apoE and low-density lipoprotein receptor-deficient mice using adenoviral-mediated gene transfer and used VLDL particles obtained from these mice for in vitro lipolysis assay. Overexpression of apoE, regardless of its isoforms, increased the TG content of VLDL in mice in vivo. In vitro analysis of the effect of apoE on lipolysis revealed that irrespective of its isoforms, apoE did inhibit TG lipolysis at every concentration of apoE examined, and this inhibitory effect became more pronounced as the apoE content of VLDL increased. No difference was observed in TG lipolysis activity among isoforms at low apoE/TG ratio; however, intermediate ratios of apoE/TG, which reflect physiologic VLDL apoE/TG ratios, demonstrated a significantly greater level of lipolysis inhibition in apoE2, but less so in apoE4 compared with other isoforms. This differential effect by apoE isoforms on lipolysis was attenuated at higher apoE/TG ratios; nevertheless, apoE2 still inhibited lipolysis significantly more than did apoE4. Enrichment of VLDL with apoE decreased both the apoC contents and apoC-II/C-III ratios of VLDL, contributing, at least in part, to the inhibitory function of apoE on lipolysis. The present study clarifies the differential lipolysis-modulating effect of apoE isoforms, which would help explain the difference in pre- and postprandial TG levels among humans carrying different apoE isoforms.

Gene polymorphisms in the Quebec population: a risk to develop hypertriglyceridemia

In Eastern Québec, two major lipoprotein lipase (LPL) gene mutations, P207L and G188E, lead to complete LPL deficiency in homozygote subjects and contribute to elevated predisposition to hypertriglyceridemia in heterozygotes. First, we determined the allele frequencies of LPL (D9N, G188E, P207L, D250N, N291S, and S447X), APOE (C112R and C158R), PPARalpha (L162V), and PPARgamma2 (P12A) single nucleotide polymorphisms (SNPs) in a random-based cohort of the metropolitan Québec city area. Second, we compared the LPL X447 allele frequencies observed in the random cohort and in a cohort of LPL P207L deficient patients. In the random cohort, the LPL N9 rare allele exhibited a higher prevalence than previously expected (p=0.0001). The LPL X447 allele frequency was lower in the patient cohort (Freq: 4.4%) than in the random cohort (Freq: 11.2%) (p=0.0001). These results reveal the importance of genetic screening for LPL gene mutations D9N and S447X in a population at risk to develop hypertriglyceridemia.

Impact of native VLDL on tissue factor pathway inhibitor in endothelial cells and interactions between TFPI and lipoprotein lipase

Tissue factor pathway inhibitor (TFPI) is a potent inhibitor of tissue factor (TF)-induced blood coagulation. A positive association between very low density lipoproteins (VLDLs) and TFPI has been reported in vivo. In contrast, one in vitro study indicates that TFPI may enhance lipoprotein lipase (LPL) activity, thereby increasing triglyceride hydrolysis. The current study was conducted to investigate how native VLDL influenced the synthesis and release of TFPI in endothelial cells, and how TFPI affected the LPL-induced hydrolysis of VLDL in vitro and at the endothelial surface. A spontaneously transformed immortal endothelial cell line (ECV304) and primary coronary artery cells (CoEc) were used, and VLDL was isolated from healthy volunteers by density gradient ultracentrifugation. Sequential free fatty acid (FFA) measurements were used to evaluate the kinetics of the LPL-induced hydrolysis. The levels of TFPI mRNAs in the stimulated cells were determined by quantitative real-time reverse transcription-ploymerase chain reaction (qPCR) using the ABI PRISM 7700 Sequence Detection System. Stimulation of ECV304 cells for 24 hours with native VLDL (0-100 microg/mL) caused a dose-dependent increase of TFPI in the medium (6.7-23.8 ng/10(6) cells, P < 0.001), without affecting the cellular content of TFPI. The expression of TFPI mRNA was significantly upregulated after 10 minutes of stimulation with n-VLDL. Both recombinant TFPI (r-TFPI) and LPL showed a dose-dependent binding to ECV 304 cells without saturation, and no competitive binding interactions between LPL and TFPI were observed at the endothelial surface. The addition of increasing concentrations of r-TFPI to ECV 304 cells, preincubated with LPL, did not affect the hydrolysis of VLDL triglycerides. The maximal reaction velocity (V(max)) of LPL-induced hydrolysis of n-VLDL was not affected by the addition of increasing concentrations of r-TFPI to the reaction mixture in vitro. The current experimental study indicates an upregulation of TFPI synthesis and release by VLDL. LPL-induced hydrolysis of VLDL in vitro was not influenced by TFPI neither in suspension nor at the endothelial surface.

A brief history of lipid and lipoprotein measurements and their contribution to clinical chemistry

The study of modern lipid chemistry began in the 17th and 18th centuries with early observations by Robert Boyle, Poulletier de la Salle, Antoine François de Fourcroy and others. The 19th century chemist, Chevreul, identified several fatty acids, suggested the name 'cholesterine' for the fatty substance in gallstones, coined the word 'glycerine', and showed that fats were comprised of glycerol and fatty acids. The 20th century brought many advances in the understanding of lipoprotein structure and function, and explored relationships between lipoproteins and disease states. The development of the ultracentrifuge and other lipoprotein separation techniques, and reagents for accurate, standardized quantitative measurement have steadily increased our understanding of the important role of lipoprotein metabolism in both healthy and disease states.

Characterization of hypertriglyceridemia-induced erectile dysfunction

OBJECTIVES

To characterize the effects of experimental hypertriglyceridemia on erectile function.

METHODS

The daily water intake of 40 sexually mature male rats (groups II to V) was supplemented for 12 weeks with 10% fructose solution to induce hypertriglyceridemia. In addition, animals from three groups (III, IV, and V) were given through daily oral gavage metformin (group III), fenofibrate (group IV), and fish oil (group V) to estimate their therapeutic effects on fructose-induced metabolic alterations. Another group (I) of 10 rats served as controls. At 12 weeks, changes in sexual behavior and cavernous pressure response to nerve stimulation were correlated with serum triglyceride levels and response to preventive measures.

RESULTS

After administration of 10% fructose, triglyceride levels increased fourfold to 1.79 +/- 0.31 mmol/L (mean +/- standard deviation) (group II). Coinciding with this elevation was a significant impairment of the copulatory pattern, with prolongation of mount (3.70 +/- 3.44 minutes), intromission (7.09 +/- 4.49 minutes), and ejaculatory latencies and reduced intracavernous pressure (27.56 +/- 2.04 mm Hg) response to nerve electrical stimulation. Whereas similar significant impairment was seen in group III, the other two groups (IV and V) showed beneficial effects of triglyceride reduction on these parameters.

CONCLUSIONS

Our results provide the first evidence for an impact of triglycerides on erectile function. This detrimental effect is likely to be due to functional vascular and neuronal deficits related to hypertriglyceridemia.

Effects of the insoluble fiber derived from Passiflora edulis seed on plasma and hepatic lipids and fecal output

The influence of the insoluble fiber-rich fraction (FRF) prepared from defatted Passiflora edulis seed, a potential fiber source, on plasma and hepatic lipids and fecal output were investigated in hamsters fed a hypercholesterolemic diet containing 5% insoluble FRF. The results showed that the consumption of insoluble FRF diet relative to cellulose diet could effectively (P < 0.05) decrease the levels of serum triglyceride, serum total cholesterol, and liver cholesterol, and increase (P < 0.05) the levels of total lipids, cholesterol, and bile acids in feces. The consumption of insoluble FRF also increased (P < 0.05) the fecal bulk and moisture. The marked cholesterol- and lipid-lowering effects of insoluble FRF might be partly attributed to its ability to enhance the excretion of lipids and bile acids via feces. Our results suggested that insoluble FRF could be a potential hypocholesterolemic ingredient for fiber-rich functional foods, but some further researches in humans may be needed to confirm its benefits.

A genome wide quantitative trait linkage analysis for serum lipids in type 2 diabetes in an African population

Lipid abnormalities are strongly linked with coronary heart disease and are common in type 2 diabetes. However, little is known about the genetic determinants of serum lipids in African populations. An autosomal genome scan was performed for linkage to five plasma lipid phenotypes (total cholesterol, triglycerides (TG), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C) and VLDL-cholesterol (VLDL-C)) in the Africa-America Diabetes Mellitus (AADM) study. Two hundred and ninety-five affected sibling pairs with type 2 diabetes mellitus enrolled from Ghana and Nigeria were genotyped for 390 microsatellite markers with an average inter-marker distance of 9cM. Multipoint variance components linkage analysis showed that HDL-C had a LOD score of 4.34 near marker D7S3061 and 3.00 near marker D7S513. Some clustering of linkage evidence to several lipid phenotypes was observed on chromosomes 5 (LDL-C, total cholesterol, VLDL-C), chromosome 7 (HDL-C, TG) and chromosome 19 (total cholesterol, LDL-C, TG). Principal component analysis of the five phenotypes yielded two factors, one (TG, HDL-C and VLDL) of which was linked to QTLs on chromosomes 2, 5 and 7, while the other (total cholesterol and LDL-C) was linked to a different set of QTLs on chromosomes 2, 5 and 18. Several of these regions have been reported to be linked to lipids in other studies. Follow up investigations are warranted in view of the central role serum lipids play in the aetiopathogenesis of cardiovascular disease.

Acute Effect of High-Fat Meal on Endothelial Function in Moderately Dyslipidemic Subjects

OBJECTIVE

Hypercholesterolemia markedly impairs endothelial function. Whether this is the case for hypertriglyceridemia is less clear, however, and limited evidence exists on the effect of an acute increase in triglyceridemia caused by a high-fat meal.

METHODS AND RESULTS

In 16 normotensive subjects with an untreated mild hypertriglyceridemia and dyslipidemia and in 7 normal controls, we measured radial artery diameter and blood flow by an echo-tracking device (NIUS02). Data were obtained at baseline, at the release of a 4-minute ischemia of the hand, which causes an increase in arterial diameter dependent on nitric oxide (NO) secretion, and at the release of a 12-minute exclusion of the arm by an arm cuff to obtain a larger increase in arterial diameter mainly of nonendothelial nature. Measurements were performed before and 6 hours after a high-fat meal (680 kcal/m(2) body surface; 82% lipids). In mild dyslipidemic hypertriglyceridemic subjects, the high-fat meal did not alter baseline blood pressure (beat-to-beat finger measurement), heart rate, radial artery diameter, and blood flow. It also did not alter the increase in blood flow induced by the 4-minute ischemia (+42.7+/-10.4 and +43.7+/-10.4 mL/min), whereas it markedly attenuated the concomitant increase in arterial diameter (+0.31+/-0.06 versus 0.13+/-0.06 mm; P<0.05). The alteration of the diameter response did not correlate with changes in total cholesterol, but it showed a significant correlation with the increase in serum triglycerides induced by high-fat meal (r=0.49, P<0.05). This attenuation was not seen in control subjects and in subjects in whom measurements were repeated after a 6-hour observation period. It was also not paralleled by an alteration of the endothelially independent response to a 12-minute ischemia whose larger effects on arterial diameter and blood flow were similar before and after the high-fat meal.

CONCLUSIONS

Endothelial function is markedly impaired by a high-fat meal that causes an acute hypertriglyceridemia. This impairment is evident in dyslipidemic patients with baseline hypertriglyceridemia but not in normotriglyceridemic controls. An oral fat load was administered to 55 HIV-positive and 10 HIV-negative individuals. Postprandial clearance of triglyceride-rich lipoproteins was delayed in HIV-positive individuals. Compared with HIV-positive subjects not on PIs, those taking PIs do not have increased postprandial triglyceride-rich lipoproteins but do have increased postprandial intermediate-density and low-density lipoproteins. Hypercholesterolemia impairs endothelial function, whereas the effect of hypertriglyceridemia is less clear. In normotensive subjects with an untreated hypertriglyceridemia and hypercholesterolemia, we measured endothelial function before and 6 hours after a high-fat meal. The results demonstrate that in moderately dyslipidemic patients, endothelial function is impaired by acute hypertriglyceridemia.

Population prevalence of APOE, APOC3 and PPAR-α mutations associated to hypertriglyceridemia in French Canadians

Hypertriglyceridemia (HTG) is known as a common metabolic disorder associated with increased production, decrease catabolism and/or decreased hepatic uptake of triglyceride (TG)-rich particles. We assessed, in the Quebec City population, the allele frequency and haplotype distributions of mutations in genes related to HTG, such as the apolipoprotein E (APOE) (C112R and C158R), the apolipoprotein CIII (APOC3) (C-482T and C3238G) and the peroxisome proliferator-activated receptor alpha (PPARalpha) (L162V) genes. A total of 938 anonymous unlinked newborns from the metropolitan Quebec City area have been genotyped. Allele frequencies observed in the Quebec City population differed from known frequencies determined in other Caucasian populations. The co-transmitted allele distribution between the two-marker genotypes APOE/APOC3(C3238G) and APOC3(C-482T)/PPARalpha(L162V) presented a weak deviation from the assumption of genetic independence. Also, we observed a non-independent distribution of the T-482/G3238 allele combinations within the APOC3 gene, suggesting strong linkage disequilibrium between the C-482T and C3238G polymorphisms. Moreover, comparisons of allele frequencies observed in the population of Québec City to those obtained in other Caucasian populations suggested that the population of Québec City may be at a lower risk of developing HTG due to APOE, APOC3 and PPARalpha genetic variants. However, the strong linkage disequilibrium and the two-marker genotype distributions observed in the APOC3 gene suggest that these two variants may functionally interact in the Québec City population.

Storage of human plasma samples leads to alterations in the lipoprotein distribution of apoC-III and apoE

The effect of frozen storage on lipoprotein distribution of apolipoprotein C-III (apoC-III) and apoE was investigated by measuring apoC-III and apoE by ELISA in HDL and apoB-containing lipoproteins of human plasma samples (n = 16) before and after 2 weeks of frozen storage (-20 degrees C). HDLs were separated by heparin-manganese precipitation (HMP) or by fast-protein liquid chromatography (FPLC). Total plasma apoC-III and apoE levels were not affected by frozen storage. HDL-HMP apoC-III and apoE levels were significantly higher in frozen versus fresh samples: 7.7 +/- 0.7 versus 6.7 +/- 0.7 mg/dl (P < 0.05) and 2.0 +/- 0.1 versus 1.2 +/- 0.1 mg/dl (P < 0.001), respectively. HDL-FPLC apoC-III and apoE, but not triglyceride (TG) or cholesterol, levels were also higher in frozen samples: 12.0 +/- 1.2 versus 7.5 +/- 0.6 mg/dl (P < 0.001) and 2.7 +/- 0.2 versus 1.6 +/- 0.2 mg/dl (P < 0.001), respectively. Frozen storage led to a decrease in apoC-III (-17 +/- 9%) and apoE (-19 +/- 9%) in triglyceride-rich lipoprotein. Redistribution of apoC-III and apoE was most evident in samples with high TG levels. HDL apoC-III and apoE levels were also significantly higher when measured in plasma stored at -80 degrees C. Our results demonstrate that lipoprotein distribution of apoC-III and apoE is affected by storage of human plasma, suggesting that analysis of frozen plasma should be avoided in studies relating lipoprotein levels of apoC-III and/or apoE to the incidence of coronary artery disease.

Soy protein enhances the cholesterol-lowering effect of plant sterol esters in cholesterol-fed hamsters

This study aimed to investigate whether the combination of plant sterol esters (PSE) with soy protein or soy isoflavones may have extra cholesterol-lowering effects. Male hamsters (n=20/group) were fed diets containing (g/100 g diet) (A) 20 casein (control), (B) 0.24 PSE, (C) 20 intact soy protein (replacing casein), (D) 0.02 soy isoflavones, (E) 0.24 PSE plus 20 soy protein (replacing casein), or (F) 0.24 PSE plus 0.02 soy isoflavones, for 5 wk. All diets contained 0.08 g cholesterol/100 g diet. Compared with the control diet, the PSE and soy protein diets significantly lowered the plasma total cholesterol concentration by 13% (P<0.05) and 9% (P<0.05), respectively, whereas the isoflavone diet (D) had no effect. The combination of PSE and soy protein (diet E) decreased plasma total cholesterol by 26% (P<0.05). The decrease in plasma cholesterol concentration was mainly in the non-HDL fraction. In addition, the combination of PSE and soy protein significantly decreased plasma triacylglycerol concentration (37%, P<0.05) and reduced cholesterol accumulation in the liver. The abundance of hepatic LDL-receptors was not influenced by any of the test diets. PSE selectively increased fecal excretion of neutral sterols by 190% (P<0.05), whereas soy protein increased fecal excretion of neutral sterols and bile acids by 66% (P<0.05) and 130% (P<0.05), respectively. The combination of PSE and soy protein increased the fecal excretion of neutral sterols and bile acids compared with PSE and soy protein alone. In conclusion, the combination of PSE and soy protein more dramatically lowers plasma lipids than the individual ingredients.

Appropriateness of cholesterol and triglycerides reporting checked by External Quality Assessment programs

BACKGROUND

The recommendations of the Second Joint Task Force of European and Other Societies on Coronary Prevention and the third Adult Treatment Panel report (ATPIII) released by the National Cholesterol Education Program are based on accumulating evidence concerning the contribution of lipoproteins and other risk factors in the development of coronary heart disease (CHD). The laboratories play an important role in the successful adoption of these guidelines.

METHODS

In External Quality Assessment (EQA) programs managed by the Center of Biomedical Research, results and respective reference intervals (RI) are sent as laboratory's medical form. We assessed how well the 200 participants to EQA scheme 2002 for clinical biochemistry reported total cholesterol (TC) and triglycerides (TGs) results according to either European or National Cholesterol Education Program (NCEP) guidelines.

RESULTS

Only 18% of laboratories reported total cholesterol concentrations correctly in terms of desirable, borderline-high, and high risk for the CHD development, 12% reported a single desirable value (180, 190, or 200 mg/dl), and 70% reported the RI (85 laboratories in the whole interval, 34 are the only upper reference limit and 15 are the desirable value in addition to RI). The upper reference limit was 200 mg/dl in 65% of cases, but 32% of laboratories presented higher limits, reaching values as high as 250-260 mg/dl. Only the 3.7% of laboratories reported triglyceride concentrations in terms of risk-oriented ranges for the CHD development, 6.8% the single desirable value, and 89.5% the RI.

CONCLUSION

Our study demonstrates that the current practice of reporting results for cholesterol and triglycerides does not follow the guidelines, and appropriate changes are required to be made.

Dietary sodium chloride restriction enhances aortic wall lipid storage and raises plasma lipid concentration in LDL receptor knockout mice

This study aimed at measuring the influence of a low salt diet on the development of experimental atherosclerosis in moderately hyperlipidemic mice. Experiments were carried out on LDL receptor (LDLR) knockout (KO) mice, or apolipoprotein E (apoE) KO mice on a low sodium chloride diet (LSD) as compared with a normal salt diet (NSD). On LSD, the rise of the plasma concentrations of TG and nonesterified fatty acid (NEFA) was, respectively, 19% and 34% in LDLR KO mice, and 21% and 35% in apoE KO mice, and that of plasma cholesterol was limited to the LDLR KO group alone (15%). Probably due to the apoE KO severe hypercholesterolemia, the arterial inner-wall fat storage was not influenced by the diet salt content and was far more abundant in the apoE KO than in the LDLR KO mice. However, in the less severe hypercholesterolemia of the LDLR KO mice, lipid deposits on the LSD were greater than on the NSD. Arterial fat storage correlated with NEFA concentrations in the LDLR KO mice alone (n = 14, P = 0.0065). Thus, dietary sodium chloride restriction enhances aortic wall lipid storage in moderately hyperlipidemic mice.

The renin-angiotensin system is involved in the production of plasminogen activator inhibitor type 1 by cultured endothelial cells in response to chylomicron remnants

Triglyceride-rich lipoproteins have been suggested to promote atherosclerosis. Plasminogen activator inhibitor type 1 (PAI-1) plays an important role in the events of cardiovascular pathophysiology. The renin-angiotensin system influences various vascular functions, including PAI-1 production. We examined whether or not chylomicron remnants increased PAI-1 mRNA and protein production in endothelial cells and whether or not an inhibition of the renin-angiotensin system interfered with this effect. Chylomicron remnants were isolated from functionally hepatectomized rats injected with chylomicrons. Human umbilical vein endothelial cell cultures (HUVECs) were incubated with chylomicron remnants with or without an angiotensin-converting enzyme inhibitor (temocaprilat), an angiotensin II receptor type 1 antagonist (RNH-6270), or an angiotensin II receptor type 2 antagonist (PD123319). Chylomicron remnants increased PAI-1 secretion in HUVECs (0.5 microg/ml; 128.3 +/- 6.1%, the mean +/- SEM) as well as angiotensin II (10 nmol/l; 130.7 +/- 9.5%) in 18 h, as compared with the controls, as well as stimulated PAI-1 mRNA expression to a maximum level at 4 h. Temocaprilat and RNH-6270, but not PD123319, attenuated all of these effects. Chylomicron remnants enhanced nuclear extract binding to a very low-density lipoprotein response element in the PAI-1 promoter region and activated nuclear factor-kappaB. Extracellular signal-regulated kinase (ERK 1/2) was phosphorylated in response to chylomicron remnants. These effects were inhibited by temocaprilat or RNH-6270. In conclusion, chylomicron remnants increased protein secretion and mRNA expression of PAI-1 in HUVECs. Inhibition of the renin-angiotensin system reduced this stimulation.

Identification of Rev-erbalpha as a physiological repressor of apoC-III gene transcription

Elevated serum levels of triglyceride-rich remnant lipoproteins (TRL) are a major risk factor predisposing a subject to atherosclerosis. Apolipoprotein C-III (apoC-III) is a major constituent of TRL that impedes triglyceride hydrolysis and remnant clearance and, as such, may exert pro-atherogenic activities. In the present study, transient cotransfection experiments in rat hepatocytes in primary culture and rabbit kidney RK13 cells demonstrated that overexpression of Rev-erbalpha specifically decreases basal and HNF-4 stimulated human apoC-III promoter activity. A Rev-erbalpha response element was mapped by promoter deletion, mutation analysis, and gel-shift experiments to a AGGTCA half-site located at position -23/-18 (downstream of the TATA box) in the apoC-III promoter. Finally, Rev-erbalpha-deficient mice displayed elevated serum and liver mRNA levels of apoC-III together with increased serum VLDL triglycerides. Taken together, our data identify Rev-erbalpha as a regulator of apoC-III gene expression, providing a novel, physiological role for this nuclear receptor in the regulation of lipid metabolism.