Effect of dietary fat saturation on LDL oxidation and monocyte adhesion to human endothelial cells in vitro

Crosstalk between high-density lipoproteins and endothelial cells in health and disease: Insights into sex-dependent modulation

Atherosclerotic cardiovascular disease is the leading cause of death worldwide. Intense research in vascular biology has advanced our knowledge of molecular mechanisms of its onset and progression until complications; however, several aspects of the patho-physiology of atherosclerosis remain to be further elucidated. Endothelial cell homeostasis is fundamental to prevent atherosclerosis as the appearance of endothelial cell dysfunction is considered the first pro-atherosclerotic vascular modification. Physiologically, high density lipoproteins (HDLs) exert protective actions for vessels and in particular for ECs. Indeed, HDLs promote endothelial-dependent vasorelaxation, contribute to the regulation of vascular lipid metabolism, and have immune-modulatory, anti-inflammatory and anti-oxidative properties. Sex- and gender-dependent differences are increasingly recognized as important, although not fully elucidated, factors in cardiovascular health and disease patho-physiology. In this review, we highlight the importance of sex hormones and sex-specific gene expression in the regulation of HDL and EC cross-talk and their contribution to cardiovascular disease.

Nontargeted Metabolomic Profiling of Huo-Tan-Chu-Shi Decoction in the Treatment of Coronary Heart Disease with Phlegm-damp Syndrome

Background

Considered an effective supplementary therapy, traditional Chinese medicine (TCM) has been widely applied in the treatment of coronary heart disease (CHD). In this study, we aim to investigate the effects and mechanisms of Huo-Tan-Chu-Shi decoction (HTCSD, an in-hospital TCM prescription) in the treatment of CHD with the phlegm-damp syndrome in mice by non-targeted metabolomics with liquid chromatography-mass spectrometry (LC-MS)/MS.

Methods

A CHD with phlegm-damp syndrome model was established with ApoE^−/− mice by subcutaneous injection with isoproterenol combined with high temperature, high humidity, and a high-fat diet, and divided into the HTCSD and Tanshi groups. C57BL/6 mice were set as the control group with an ordinary environment and diet. After administration, electrocardiogram (ECG), interventricular septum thickness (IVS) and left ventricular posterior wall thickness (LVPW), serum levels of creatine phosphokinase-Mb (CK-MB), cardiac troponin T (cTnT), lactic dehydrogenase (LDH) and oxidized low-density lipoprotein (oxLDL), and myocardial histopathological changes were recorded to assess myocardial damage. LC-MS/MS was applied to demonstrate the serum metabolic profile and explore potential mechanisms.

Results

The obvious depressions of the ST segment and T wave presented in the ECG of Tanshi mice, while the depressions in ECG of HTCSD mice were significantly reduced. Compared with the control group, IVS, LVPW, and serum levels of CK-MB, cTnT, LDH, and oxLDL increased greatly in the Tanshi group, while these indicators decreased remarkably in the HTCSD group compared with those of the Tanshi group. Histopathology showed severe structural disorder, necrosis, and fibrosis of myocardial cells in Tanshi mice, which were alleviated in HTCSD mice. Metabonomics analysis showed obvious metabolic alterations among the experimental mice and revealed that the relevant metabolic pathways mainly included phospholipid metabolism, necroptosis, and autophagy.

Conclusions

HTCSD has a certain therapeutic effect in mice with CHD with phlegm-damp syndrome via reducing myocardial ischemia, hypertrophy, and fibrosis. The underlying mechanisms involve the regulation of phospholipid metabolism, necroptosis, and autophagy.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

Adipose tissue aging: mechanisms and therapeutic implications

Adipose tissue, which is the crucial energy reservoir and endocrine organ for the maintenance of systemic glucose, lipid, and energy homeostasis, undergoes significant changes during aging. These changes cause physiological declines and age-related disease in the elderly population. Here, we review the age-related changes in adipose tissue at multiple levels and highlight the underlying mechanisms regulating the aging process. We also discuss the pathogenic pathways of age-related fat dysfunctions and their systemic negative consequences, such as dyslipidemia, chronic general inflammation, insulin resistance, and type 2 diabetes (T2D). Age-related changes in adipose tissue involve redistribution of deposits and composition, in parallel with the functional decline of adipocyte progenitors and accumulation of senescent cells. Multiple pathogenic pathways induce defective adipogenesis, inflammation, aberrant adipocytokine production, and insulin resistance, leading to adipose tissue dysfunction. Changes in gene expression and extracellular signaling molecules regulate the aging process of adipose tissue through various pathways. In addition, adipose tissue aging impacts other organs that are infiltrated by lipids, which leads to systemic inflammation, metabolic system disruption, and aging process acceleration. Moreover, studies have indicated that adipose aging is an early onset event in aging and a potential target to extend lifespan. Together, we suggest that adipose tissue plays a key role in the aging process and is a therapeutic target for the treatment of age-related disease, which deserves further study to advance relevant knowledge.

In Vitro Effects of Cetylated Fatty Acids Mixture from Celadrin on Chondrogenesis and Inflammation with Impact on Osteoarthritis

OBJECTIVE

Cetylated fatty acids are a group of naturally occurring fats of plant and/or animal origin. Cetyl myristoleate, in particular, was initially involved in osteoarthritis related research as its therapeutic administration prevented experimentally induced arthritis in Swiss Albino mice. In this context, the aim of our study was to investigate the possible mechanisms of Celadrin cetylated fatty acids action at the cellular level inflammation related pain relief and chondrogenesis.

DESIGN

For this, we tested the effects of the cetylated fatty acids mixture from Celadrin on an in vitro scaffold-free 3-dimensional mesenchymal stem cells culture model of chondrogenesis. Furthermore, we treated stimulated mouse macrophage cells with the cetylated fatty acids mixture to investigate the expression profile of secreted inflammatory cytokines.

RESULTS

The cetylated fatty acids mixture from Celadrin significantly decreased the production of IL-6, MCP-1, and TNF, key regulators of the inflammatory process, in stimulated RAW264.7 mouse macrophage cells. The treatment with cetylated fatty acids mixture initiated and propagated the process of chondrogenesis as demonstrated by the increased expression and deposition of chondrogenic markers by the differentiating mesenchymal cells.

CONCLUSION

The cetylated fatty acids mixture from Celadrin reduces inflammation in vitro by significantly decreasing the expression of IL-6, MCP-1, and TNF in stimulated RAW264.7 mouse macrophage cells. These compounds facilitate the chondrogenic differentiation process of human adipose-derived stem cells by stimulating the expression of chondrogenic markers under chondrogenic induction conditions.

Diet-Modulated Lipoprotein Metabolism and Vascular Inflammation Evaluated by 18F-fluorodeoxyglucose Positron Emission Tomography

Vascular inflammation plays a central role in atherosclerosis, from initiation and progression to acute thrombotic complications. Modified low-density lipoproteins (LDLs) and apoB-containing particles stimulate plaque inflammation by interacting with macrophages. Loss of function of high-density lipoprotein (HDL) for preventing LDL particles from oxidative modification in dyslipidemic states may amplify modified LDL actions, accelerating plaque inflammation. Diets are one of the most important factors that can affect these processes of lipoprotein oxidation and vascular inflammation. Recently, ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has emerged as a reliable noninvasive imaging modality for identifying and quantifying vascular inflammation within atherosclerotic lesions based on the high glycolytic activity of macrophages infiltrating active atherosclerotic plaques. Vascular inflammation evaluated by FDG PET has been positively related to metabolic syndrome components and traditional risk factors of cardiovascular disease, including high-sensitivity C-reactive protein, body mass index, and insulin resistance. A positive association of vascular inflammation with endothelial dysfunction, resistin levels, pericardial adipose tissue, and visceral fat area has also been reported. In contrast, HDL cholesterol and adiponectin have been inversely related to vascular inflammation detected by FDG PET. Because of its reproducibility, serial FDG PET shows potential for tracking the effects of dietary interventions and other systemic and local antiatherosclerotic therapies for plaque inflammation.

Dietary Fats and Oxidative Stress: A Cross-Sectional Study Among Coronary Artery Disease Subjects Consuming Coconut Oil/Sunflower Oil

Coconut oil has been used by the people of Kerala as a cooking medium for several decades. Due to its alleged hypercholesterolemic activity, general population in recent times is shifting to cooking oils rich in polyunsaturated fats, the most popular being sunflower oil. The effect of long-term consumption of sunflower oil on oxidative stress in humans is not well investigated. We studied oxidative stress among coronary artery disease (CAD) patients who were consuming coconut oil or sunflower oil as a part of their routine diet. Men, aged 35-70 years, with established CAD, who presented to the hospital for routine cardiac evaluations, were enrolled in this observational study. Group 1 and 2 consisted of 73 and 80 subjects consuming coconut oil and sunflower oil respectively for over a period of 2 years. Lipid profile and parameters for oxidative stress were evaluated among them. Conventional lipid parameters did not differ significantly between the two groups. Mean vitamin C concentration was significantly reduced for subjects on sunflower oil compared to those consuming coconut oil (P = 0.044). Malondialdehyde was higher for sunflower oil consumers compared to coconut oil consumers (P < 0.0001). Other parameters such as oxidized LDL, GSH, GPx and SOD were not found to be significantly different between the two groups. The results of the present study show that coconut oil did not induce hypercholesterolemia compared to sunflower oil. On the other hand, sunflower oil group had elevated oxidative stress compared to coconut oil group.

The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials

BACKGROUND

A cornerstone of conventional dietary advice is the recommendation to replace saturated fatty acids (SFA) with mostly n-6 polyunsaturated fatty acids (PUFA) to reduce the risk of coronary heart disease (CHD). Many clinical trials aimed to test this advice and have had their results pooled in several meta-analyses. However, earlier meta-analyses did not sufficiently account for major confounding variables that were present in some of those trials. Therefore, the aim of the study was to account for the major confounding variables in the diet heart trials, and emphasise the results from those trials that most accurately test the effect of replacing SFA with mostly n-6 PUFA.

DESIGN

Clinical trials were identified from earlier meta-analyses. Relevant trials were categorised as 'adequately controlled' or 'inadequately controlled' depending on whether there were substantial dietary or non-dietary differences between the experimental and control groups that were not related to SFA or mostly n-6 PUFA intake, then were subject to different subgroup analyses.

RESULTS

When pooling results from only the adequately controlled trials there was no effect for major CHD events (RR = 1.06, CI = 0.86-1.31), total CHD events (RR = 1.02, CI = 0.84-1.23), CHD mortality (RR = 1.13, CI = 0.91-1.40) and total mortality (RR = 1.07, CI = 0.90-1.26). Whereas, the pooled results from all trials, including the inadequately controlled trials, suggested that replacing SFA with mostly n-6 PUFA would significantly reduce the risk of total CHD events (RR = 0.80, CI = 0.65-0.98, P = 0.03), but not major CHD events (RR = 0.87, CI = 0.70-1.07), CHD mortality (RR = 0.90, CI = 0.70-1.17) and total mortality (RR = 1.00, CI = 0.90-1.10).

CONCLUSION

Available evidence from adequately controlled randomised controlled trials suggest replacing SFA with mostly n-6 PUFA is unlikely to reduce CHD events, CHD mortality or total mortality. The suggestion of benefits reported in earlier meta-analyses is due to the inclusion of inadequately controlled trials. These findings have implications for current dietary recommendations.

Endothelial Protective Monocyte Patrolling in Large Arteries Intensified by Western Diet and Atherosclerosis

Supplemental Digital Content is available in the text.

Rationale:

Nonclassical mouse monocyte (CX3CR1^high, Ly-6C^low) patrolling along the vessels of the microcirculation is critical for endothelial homeostasis and inflammation. Because of technical challenges, it is currently not established how patrolling occurs in large arteries.

Objective:

This study was undertaken to elucidate the molecular, migratory, and functional phenotypes of patrolling monocytes in the high shear and pulsatile environment of large arteries in healthy, hyperlipidemic, and atherosclerotic conditions.

Methods and Results:

Applying a new method for stable, long-term 2-photon intravital microscopy of unrestrained large arteries in live CX3CR1-GFP (green fluorescent protein) mice, we show that nonclassical monocytes patrol inside healthy carotid arteries at a velocity of 36 μm/min, 3× faster than in microvessels. The tracks are less straight but lead preferentially downstream. The number of patrolling monocytes is increased 9-fold by feeding wild-type mice a Western diet or by applying topical TLR7/8 (Toll-like receptor) agonists. A similar increase is seen in CX3CR1^+/GFP/apoE^−/− mice on chow diet, with a further 2- to 3-fold increase on Western diet (22-fold over healthy). In plaque conditions, monocytes are readily captured onto the endothelium from free flow. Stable patrolling is unaffected in CX3CR1-deficient mice and involves the contribution of LFA-1 (lymphocyte-associated antigen 1) and α₄ integrins. The endothelial damage in atherosclerotic carotid arteries was assessed by electron microscopy and correlates with the number of intraluminal patrollers. Abolishing patrolling monocytes in Nr4a1^−/− apoE^−/− mice leads to pronounced endothelial apoptosis.

Conclusions:

Arterial patrolling is a prominent new feature of nonclassical monocytes with unique molecular and kinetic properties. It is highly upregulated in hyperlipidemia and atherosclerosis in a CX3CR1-independent fashion and plays a potential role in endothelial protection.

The Effect of Chinese Herbal Medicine Gualouxiebaibanxia Decoction for the Treatment of Angina Pectoris: A Systematic Review

We systematically assess the current clinical evidence of Gualouxiebaibanxia (GLXBBX) decoction for the treatment of angina pectoris (AP). We included RCTs testing GLXBBX against conventional drugs and GLXBBX combined with conventional drugs versus conventional drugs. 19 RCTs involving 1730 patients were finally identified, and the methodological quality was evaluated as generally low. The results of the meta-analysis showed that GLXBBX alone had significant effect on improving angina symptoms (RR: 1.24, 95% CI 1.14 to 1.35; P < 0.00001), ECG (RR: 1.28 [1.13,1.44]; P < 0.0001), and HDL-C (MD: 0.56 [0.54,0.58]; P < 0.00001) compared with anti-arrhythmic drugs. A significant improvement in angina symptoms (RR: 1.17 [1.12,1.22]; P < 0.00001) and ECG (RR = 1.22; 95% CI = [1.14,1.30]; P < 0.00001) was observed for GLXBBX plus conventional drugs when compared with conventional drugs. Eight trials reported adverse events without serious adverse effects. GLXBBX appears to have beneficial effects on improvement of ECG and reduction of angina symptoms in participants with AP. However, the evidence remains weak due to the poor methodological quality of the included studies. More rigorous trials are needed to confirm the results.

From alga to omega; have we reached peak (fish) oil?

SummaryWhile the Inuit diet was highly cardio-protective and consuming oily fish within a Western diet is to a lesser degree, the case for purified fish oil supplements is less convincing. Purification of fish oil removes lipophilic polyphenols which likely contribute to the health benefits of oily fish; leaving the ω3 highly unsaturated fatty acids exposed and prone to conferring oxidative and inflammatory stress. The authors believe that due to such issues as dietary shift, it may now be inadvisable to prescribe or sell purified ω3 highly unsaturated fatty acids supplements, unless the appropriate co-factors are included.

Atherogenesis: hyperhomocysteinemia interactions with LDL, macrophage function, paraoxonase 1, and exercise

Despite great strides in understanding the atherogenesis process, the mechanisms are not entirely known. In addition to diet, cigarette smoking, genetic predisposition, and hypertension, hyperhomocysteinemia (HHcy), an accumulation of the noncoding sulfur-containing amino acid homocysteine (Hcy), is a significant contributor to atherogenesis. Although exercise decreases HHcy and increases longevity, the complete mechanism is unclear. In light of recent evidence, in this review, we focus on the effects of HHcy on macrophage function, differentiation, and polarization. Though there is need for further evidence, it is most likely that HHcy-mediated alterations in macrophage function are important contributors to atherogenesis, and HHcy-countering strategies, such as nutrition and exercise, should be included in the combinatorial regimens for effective prevention and regression of atherosclerotic plaques. Therefore, we also included a discussion on the effects of exercise on the HHcy-mediated atherogenic process.

A systematic review of high-oleic vegetable oil substitutions for other fats and oils on cardiovascular disease risk factors: implications for novel high-oleic soybean oils

High-oleic acid soybean oil (H-OSBO) is a trait-enhanced vegetable oil containing >70% oleic acid. Developed as an alternative for trans-FA (TFA)-containing vegetable oils, H-OSBO is predicted to replace large amounts of soybean oil in the US diet. However, there is little evidence concerning the effects of H-OSBO on coronary heart disease (CHD)(6) risk factors and CHD risk. We examined and quantified the effects of substituting high-oleic acid (HO) oils for fats and oils rich in saturated FAs (SFAs), TFAs, or n-6 (ω-6) polyunsaturated FAs (PUFAs) on blood lipids in controlled clinical trials. Searches of online databases through June 2014 were used to select studies that defined subject characteristics; described control and intervention diets; substituted HO oils compositionally similar to H-OSBO (i.e., ≥70% oleic acid) for equivalent amounts of oils high in SFAs, TFAs, or n-6 PUFAs for ≥3 wk; and reported changes in blood lipids. Studies that replaced saturated fats or oils with HO oils showed significant reductions in total cholesterol (TC), LDL cholesterol, and apolipoprotein B (apoB) (P < 0.05; mean percentage of change: -8.0%, -10.9%, -7.9%, respectively), whereas most showed no changes in HDL cholesterol, triglycerides (TGs), the ratio of TC to HDL cholesterol (TC:HDL cholesterol), and apolipoprotein A-1 (apoA-1). Replacing TFA-containing oil sources with HO oils showed significant reductions in TC, LDL cholesterol, apoB, TGs, TC:HDL cholesterol and increased HDL cholesterol and apoA-1 (mean percentage of change: -5.7%, -9.2%, -7.3%, -11.7%, -12.1%, 5.6%, 3.7%, respectively; P < 0.05). In most studies that replaced oils high in n-6 PUFAs with equivalent amounts of HO oils, TC, LDL cholesterol, TGs, HDL cholesterol, apoA-1, and TC:HDL cholesterol did not change. These findings suggest that replacing fats and oils high in SFAs or TFAs with either H-OSBO or oils high in n-6 PUFAs would have favorable and comparable effects on plasma lipid risk factors and overall CHD risk.

Alteration in metabolic signature and lipid metabolism in patients with angina pectoris and myocardial infarction

Lipid metabolites are indispensable regulators of physiological and pathological processes, including atherosclerosis and coronary artery disease (CAD). However, the complex changes in lipid metabolites and metabolism that occur in patients with these conditions are incompletely understood. We performed lipid profiling to identify alterations in lipid metabolism in patients with angina and myocardial infarction (MI). Global lipid profiling was applied to serum samples from patients with CAD (angina and MI) and age-, sex-, and body mass index-matched healthy subjects using ultra-performance liquid chromatography/quadruple time-of-flight mass spectrometry and multivariate statistical analysis. A multivariate analysis showed a clear separation between the patients with CAD and normal controls. Lysophosphatidylcholine (lysoPC) and lysophosphatidylethanolamine (lysoPE) species containing unsaturated fatty acids and free fatty acids were associated with an increased risk of CAD, whereas species of lysoPC and lyso-alkyl PC containing saturated fatty acids were associated with a decreased risk. Additionally, PC species containing palmitic acid, diacylglycerol, sphingomyelin, and ceramide were associated with an increased risk of MI, whereas PE-plasmalogen and phosphatidylinositol species were associated with a decreased risk. In MI patients, we found strong positive correlation between lipid metabolites related to the sphingolipid pathway, sphingomyelin, and ceramide and acute inflammatory markers (high-sensitivity C-reactive protein). The results of this study demonstrate altered signatures in lipid metabolism in patients with angina or MI. Lipidomic profiling could provide the information to identity the specific lipid metabolites under the presence of disturbed metabolic pathways in patients with CAD.

Oxidized low-density lipoprotein contributes to atherogenesis via co-activation of macrophages and mast cells

Oxidized low-density lipoprotein (OxLDL) is a risk factor for atherosclerosis, due to its role in endothelial dysfunction and foam cell formation. Tissue-resident cells such as macrophages and mast cells release inflammatory mediators upon activation that in turn cause endothelial activation and monocyte adhesion. Two of these mediators are tumor necrosis factor (TNF)-α, produced by macrophages, and histamine, produced by mast cells. Static and microfluidic flow experiments were conducted to determine the number of adherent monocytes on vascular endothelium activated by supernatants of oxLDL-treated macrophages and mast cells or directly by oxLDL. The expression of adhesion molecules on activated endothelial cells and the concentration of TNF-α and histamine in the supernatants were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. A low dose of oxLDL (8 μg/ml), below the threshold for the clinical presentation of coronary artery disease, was sufficient to activate both macrophages and mast cells and synergistically increase monocyte-endothelium adhesion via released TNF-α and histamine. The direct exposure of endothelial cells to a much higher dose of oxLDL (80 μg/ml) had less effect on monocyte adhesion than the indirect activation via oxLDL-treated macrophages and mast cells. The results of this work indicate that the co-activation of macrophages and mast cells by oxLDL is an important mechanism for the endothelial dysfunction and atherogenesis. The observed synergistic effect suggests that both macrophages and mast cells play a significant role in early stages of atherosclerosis. Allergic patients with a lipid-rich diet may be at high risk for cardiovascular events due to high concentration of low-density lipoprotein and histamine in arterial vessel walls.

Ageing, adipose tissue, fatty acids and inflammation

A common feature of ageing is the alteration in tissue distribution and composition, with a shift in fat away from lower body and subcutaneous depots to visceral and ectopic sites. Redistribution of adipose tissue towards an ectopic site can have dramatic effects on metabolic function. In skeletal muscle, increased ectopic adiposity is linked to insulin resistance through lipid mediators such as ceramide or DAG, inhibiting the insulin receptor signalling pathway. Additionally, the risk of developing cardiovascular disease is increased with elevated visceral adipose distribution. In ageing, adipose tissue becomes dysfunctional, with the pathway of differentiation of preadipocytes to mature adipocytes becoming impaired; this results in dysfunctional adipocytes less able to store fat and subsequent fat redistribution to ectopic sites. Low grade systemic inflammation is commonly observed in ageing, and may drive the adipose tissue dysfunction, as proinflammatory cytokines are capable of inhibiting adipocyte differentiation. Beyond increased ectopic adiposity, the effect of impaired adipose tissue function is an elevation in systemic free fatty acids (FFA), a common feature of many metabolic disorders. Saturated fatty acids can be regarded as the most detrimental of FFA, being capable of inducing insulin resistance and inflammation through lipid mediators such as ceramide, which can increase risk of developing atherosclerosis. Elevated FFA, in particular saturated fatty acids, maybe a driving factor for both the increased insulin resistance, cardiovascular disease risk and inflammation in older adults.

Fasting whole blood fatty acid profile and risk of type 2 diabetes in adults: a nested case control study

Objective

to determine the association of fasting whole blood fatty acid concentrations with incidence of type 2 diabetes in adults.

Methods

A nested case-control study of 187 subjects from a cohort of men and women aged 55–85 years from the Hunter Region, New South Wales, Australia. Fasting whole blood fatty acids were measured using gas chromatography and incidence of type 2 diabetes was ascertained by self-reported questionnaire at the study follow-up.

Results

After adjustment for potential confounding variables, positive associations with type 2 diabetes were seen for dihomo-gamma-linolenic acid (DGLA) (OR = 1.04, 95% CI:1.01–1.07, P = 0.01); arachidonic acid (ARA) (OR = 1.01, 95% CI:1.00–1.01, P = 0.002); alpha-linolenic acid (ALA) (OR = 1.10, 95% CI: 1.03–1.18, P = 0.01); eicosapentaenoic acid (EPA) (OR = 1.05, 95% CI:1.02–1.08, P = 0.001); and docosahexaenoic acid (DHA) (OR = 1.03, 95% CI:1.02–1.05, P<0.0001). Lignoceric acid is significantly associated with lower type 2 diabetes risk (OR = 0.95, 95% CI: 0.92–0.99, P = 0.01).

Conclusion

These data suggest that higher fasting whole blood concentrations of omega-6 polyunsaturated fatty acids (n-6PUFA) (ARA and DGLA) as well as omega-3 polyunsaturated fatty acid (n-3PUFA) (ALA, EPA, and DHA) are associated with an increased risk of diabetes, whereas increased fasting whole blood concentrations of lignoceric acid is inversely associated with diabetes risk.

The single-nucleotide polymorphism (GPX4c718t) in the glutathione peroxidase 4 gene influences endothelial cell function: interaction with selenium and fatty acids

SCOPE

Selenium (Se) is incorporated into selenoproteins as selenocysteine, which requires structures in the 3'-untranslated region (3'-UTR) of selenoprotein mRNAs. The functional consequences of a single nucleotide polymorphism (SNP) within the 3'-UTR of the selenoprotein GPX4 gene (GPX4c718t) was assessed in human umbilical vein endothelial cells (HUVECs) and monocytes from human volunteers.

METHODS AND RESULTS

HUVEC and monocytes homozygous for the T- or C-variant of the GPX4c718t SNP were assessed for monocyte-endothelial cell adhesion, expression of VCAM-1 and sensitivity to oxidative challenge. Interaction of the SNP with Se and different PUFA and effects on selenoprotein expression were also investigated. HUVEC and monocytes homozygous for the T-variant showed elevated adhesion levels compared to cells of the C-variant. This effect was modified by Se and PUFA. HUVEC homozygous for the T-variant showed elevated levels of VCAM-1 protein in the presence of arachidonic acid, were more sensitive to oxidative challenge and showed Se-dependant changes in lipid peroxide levels and expression of additional selenoproteins.

CONCLUSION

These findings demonstrate functional effects of the GPX4c718t SNP in endothelial cells and may suggest that individuals with the TT genotype have impaired endothelial function and are at greater risk of vascular disease compared to individuals with the CC genotype.

Coronary heart disease prevention: nutrients, foods, and dietary patterns

Diet is a key modifiable risk factor in the prevention and risk reduction of coronary heart disease (CHD). Results from the Seven Countries Study in the early 1970s spurred an interest in the role of single nutrients such as total fat in CHD risk. With accumulating evidence, we have moved away from a focus on total fat to the importance of considering the quality of fat. Recent meta-analyses of intervention studies confirm the beneficial effects of replacing saturated fat with polyunsaturated fatty acids on CHD risk. Scientific evidence for a detrimental role of trans fat intake from industrial sources on CHD risk has led to important policy changes including listing trans fatty acid content on the "Nutrition Facts" panel and banning the use of trans fatty acids in food service establishments in some cities. The effects of such policy changes on changes in CHD incidence are yet to be evaluated. There has been a surging interest in the protective effects of vitamin D in primary prevention. Yet, its associations with secondary events have been mixed and intervention studies are needed to clarify its role in CHD prevention. Epidemiological and clinical trial evidence surrounding the benefit of B vitamins and antioxidants such as carotenoids, vitamin E, and vitamin C, have been contradictory. While pharmacological supplementation of these vitamins in populations with existing CHD has been ineffective and, in some cases, even detrimental, data repeatedly show that consumption of a healthy dietary pattern has considerable cardioprotective effects for primary prevention. Results from these studies and the general ineffectiveness of nutrient-based interventions have shifted interest to the role of foods in CHD risk reduction. The strongest and most consistent protective associations are seen with fruit and vegetables, fish, and whole grains. Epidemiological and clinical trial data also show risk reduction with moderate alcohol consumption. In the past decade, there has been a paradigm shift in nutritional epidemiology to examine associations between dietary patterns and health. Several epidemiological studies show that people following the Mediterranean style diet or the Dietary Approaches to Stop Hypertension (DASH) diet have lower risk of CHD and lower likelihood of developing hypertension. Studies using empirical or data driven dietary patterns have frequently identified two patterns - "Healthy or Prudent" and "Western". In general, the "Healthy", compared to the "Western" pattern has been associated with more favorable biological profiles, slower progression of atherosclerosis, and reduced incidence. Evidence on changes in dietary patterns and changes in CHD risk is still emerging. With the emergence of the concept of personalized nutrition, studies are increasingly considering the role of genetic factors in the modulation of the association between nutrients and CHD. More studies of genetic variation and dietary patterns in relation to CHD are needed.

[Inflammation and C-reactive protein in cardiovascular disease]

BACKGROUND

This article reviews the role of inflammation in development of atherosclerosis and associated complications and discusses use of the inflammatory marker - high-sensitivity C-reactive protein (hs-CRP) - in risk stratification.

MATERIAL AND METHODS

The article is based on selected publications retrieved from a non-systematic search of PubMed and the authors' experience within the field.

RESULTS

Both chronic inflammatory disease and acute infections are associated with an increased risk of cardiovascular events. Influenza vaccination reduces the risk of coronary ischaemic events in patients with coronary artery disease, but the effect on cardiovascular mortality is not documented. Hs-CRP is an independent predictor of cardiovascular events in populations with and without established cardiovascular disease. Treatment with Rosuvastatin led to decreased hs-CRP-levels and a reduced risk for cardiovascular events in subjects without known cardiovascular disease, with normal serum cholesterol and hs-CRP-levels above 2 mg/l.

INTERPRETATION

Individuals with chronic inflammatory disease and those with high risk and acute infection are at risk for cardiovascular events and should be evaluated for primary prevention. In patient groups at moderate risk for cardiovascular disease, hs-CRP can be a valuable supplement to established factors for risk stratification. Despite numerous studies confirming hs-CRP's role as an independent risk marker, hs-CRP has not found its place in international guidelines. This should be reconsidered on the background of new study results.

Genes, diet and type 2 diabetes mellitus: a review

Diabetes mellitus is widely recognized as one of the leading causes of death and disability. While insulin insensitivity is an early phenomenon partly related to obesity, pancreatic beta-cell function declines gradually over time even before the onset of clinical hyperglycemia. Several mechanisms have been proposed to be responsible for insulin resistance, including increased non-esterified fatty acids, inflammatory cytokines, adipokines, and mitochondrial dysfunction, as well as glucotoxicity, lipotoxicity, and amyloid formation for beta-cell dysfunction. Moreover, the disease has a strong genetic component, although only a handful of genes have been identified so far. Diabetic management includes diet, exercise and combinations of antihyperglycemic drug treatment with lipid-lowering, antihypertensive, and antiplatelet therapy. Since many persons with type 2 diabetes are insulin resistant and overweight, nutrition therapy often begins with lifestyle strategies to reduce energy intake and increase energy expenditure through physical activity. These strategies should be implemented as soon as diabetes or impaired glucose homoeostasis (pre-diabetes) is diagnosed.

Eicosapentaenoic acid and docosahexaenoic acid from fish oils: differential associations with lipid responses

Fish-oil supplementation can reduce circulating triacylglycerol (TG) levels and cardiovascular risk. This study aimed to assess independent associations between changes in platelet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and fasting and postprandial (PP) lipoprotein concentrations and LDL oxidation status, following fish-oil intervention. Fifty-five mildly hypertriacylglycerolaemic (TG 1·5–4·0 mmol/l) men completed a double-blind placebo controlled cross over study, where individuals consumed 6 g fish oil (3 g EPA+DHA) or 6 g olive oil (placebo)/d for two 6-week intervention periods, with a 12-week wash-out period in between. Fish-oil intervention resulted in a significant increase in the platelet phospholipid EPA (+491 %,P<0·001) and DHA (+44 %,P<0·001) content and a significant decrease in the arachidonic acid (-10 %,P<0·001) and γ-linolenic acid (-24 %,P<0·001) levels. A 30 % increase inex vivoLDL oxidation (P<0·001) was observed. In addition, fish oil resulted in a significant decrease in fasting and PP TG levels (P<0·001), PP non-esterified fatty acid (NEFA) levels, and in the percentage LDL as LDL-3 (P=0·040), and an increase in LDL-cholesterol (P=0·027). In multivariate analysis, changes in platelet phospholipid DHA emerged as being independently associated with the rise in LDL-cholesterol, accounting for 16 % of the variability in this outcome measure (P=0·030). In contrast, increases in platelet EPA were independently associated with the reductions in fasting (P=0·046) and PP TG (P=0·023), and PP NEFA (P=0·015), explaining 15–20 % and 25 % of the variability in response respectively. Increases in platelet EPA+DHA were independently and positively associated with the increase in LDL oxidation (P=0·011). EPA and DHA may have differential effects on plasma lipids in mildly hypertriacylglycerolaemic men.

The Mediterranean and CHO diets decrease VCAM-1 and E-selectin expression induced by modified low-density lipoprotein in HUVECs

BACKGROUND AND AIM

The oxidative modifications of low-density lipoprotein (LDL) are crucial for the atherosclerosis process. The aim of this study was to determine if the minimally modified LDL, obtained after the ingestion of three different diets, produce differential effects on the vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression in human umbilical endothelial cells (HUVECs).

METHODS AND RESULTS

Twenty healthy young males were exposed to three dietary periods. Each period lasted four weeks. During the first period, all subjects consumed a saturated fat (SFA) enriched diet (38% fat, 20% SFA). The second and third dietary periods were administered following a randomized crossover design: a low fat high carbohydrates diet (CHO diet) and a Mediterranean diet. LDL particles, isolated during each dietary period, were oxidized by exposure to UV light and incubated for 48 h with HUVEC. Thereafter, 100 U/mL of TNF-alpha was added and incubation continued for 6 h. Cellular ELISA determined adhesion molecules expression. Lag time, propagation rate and total amounts of formed conjugated dienes were calculated in LDL incubated with 10mumol/L Cu(2+). When compared to the SFA diet, LDL isolated from the Mediterranean and CHO diets induced a lower expression of VCAM-1 and E-selectin in HUVECS (P<0.007). There were no differences between both lipid lowering diets. However, lag time of LDL from the Mediterranean diet was higher than with the CHO diet (P<0.042). This parameter was inversely correlated with E-selectin expression (r=-0.497; P<0.04).

CONCLUSION

Our results suggest that both the Mediterranean and CHO diets may decrease the pro-inflammatory environment induced by modified LDL in endothelial cells.

Fatty acids and atherosclerotic risk

Most research concerning the effects of dietary fatty acids on atherosclerotic risk has focused on their effects on lipid and lipoprotein metabolism. However, it is known that fatty acids also influence a number of other relevant mechanisms involved in atherosclerosis such as lipid peroxidation, inflammation and haemostasis. The most favourable distribution of cholesterol over the various lipoproteins is achieved when saturated and trans fatty acids are replaced by a mixture of cis-unsaturated fatty acids. Furthermore, fatty acids from fish oil lower triacylglycerol concentrations. Effects on other atherosclerotic risk markers are less evident. Monounsaturated fatty acids maybe preferable above other fatty acids with respect to low-density lipoprotein oxidation as measured by indirect in vitro assays. The relevance of these assays for the in vivo situation is, however, limited. With respect to inflammation, mainly the effects of n-3 polyunsaturated fatty acids from fish oil have been studied, but results were inconsistent. Also results from studies evaluating the effects of fatty acids on haemostatic risk markers were inconsistent, which may be partly related to the use of different analytical methods. The most consistent finding however is the potential beneficial effect of moderate intakes of fish oil on platelet aggregation. Furthermore, reducing total fat intake rather than changing the fatty acid composition of the diet may beneficially affect the coagulation system. In conclusion, while beneficial effects on atherosclerotic risk are mainly ascribed to cis-unsaturated fatty acids, it remains debateable whether trans and saturated fatty acids in the diet have to be replaced by cis-unsaturated fatty acids or by carbohydrates. To answer this question adequately more validated methods are needed that reflect in vivo lipid peroxidation, inflammation and haemostasis.

A Mediterranean dietary style influences TNF-alpha and VCAM-1 coronary blood levels in unstable angina patients

BACKGROUND

A Mediterranean dietary pattern has been associated with a reduced risk of coronary heart disease, as well as a reduction of oxidative stress, but studies indicating possible interactions between food intake and inflammatory mediators production at specific sites are lacking.

AIM OF THE STUDY

To assess the relationship between Mediterranean diet consumption and inflammatory related molecules production in coronary vessels.

METHODS

A previously reported Mediterranean-diet score was computed summing-up the quintiles of eight dietary components from a validated food frequency questionnaire in 24 patients with unstable angina. Tumor necrosis factor (TNF-alpha) and vascular cell adhesion molecule (VCAM-1) concentrations were measured in coronary sinus blood.

RESULTS

Both biomarkers showed an inverse association with the Mediterraneandiet score. The association between VCAM-1 and the Mediterranean-diet score had an adjusted beta coefficient of -35.1 ng/ml (95% coefficient interval, CI: -63.5 to -6.7). The adjusted beta coefficient using TNF-alpha as the dependent variable was -41.6 pg/ml (95 % CI: -76.2 to -7.1). The consumption of olive oil as a single item showed a significant inverse association, and a Mediterranean-diet score excluding olive oil was also inversely associated with TNF-alpha and VCAM-1 serum levels in coronary venous blood.

CONCLUSIONS

Adherence to a Mediterranean dietary pattern may protect against coronary artery wall production of inflammatory mediators. This finding could provide a novel mechanistic explanation for the recognized lower coronary risk associated with a Mediterranean diet.

Decreased aortic early atherosclerosis and associated risk factors in hypercholesterolemic hamsters fed a high- or mid-oleic acid oil compared to a high-linoleic acid oil

Currently, diets higher in polyunsaturated fat are believed to lower blood cholesterol concentrations, and thus reduce atherosclerosis, greater than diets containing high amounts of saturated or possibly even monounsaturated fat. The present study was designed to investigate the effect of diets containing mid- or high-linoleic oil versus the typical high-linoleic sunflower oil on LDL oxidation and the development of early atherosclerosis in a hypercholesterolemic hamster model. Animals were fed a hypercholesterolemic diet containing 10% mid-oleic sunflower oil, high-oleic olive oil, or high-linoleic sunflower oil (wt/wt) plus 0.4% cholesterol (wt/wt) for 10 weeks. After 10 weeks of dietary treatment, only the animals fed the mid-oleic sunflower oil had significant reductions in plasma LDL-C levels (-17%) compared to the high-linoleic sunflower oil group. The high-oleic olive oil-fed hamsters had significantly higher plasma triglyceride levels (+41%) compared to the high-linoleic sunflower oil-fed hamsters. The tocopherol levels in plasma LDL were significantly higher in hamsters fed the mid-oleic sunflower oil (+77%) compared to hamsters fed either the high-linoleic sunflower or high-oleic olive oil. Measurements of LDL oxidation parameters, indicated that hamsters fed the mid-oleic sunflower oil and high-oleic olive oil diets had significantly longer lag phase (+66% and +145%, respectively) and significantly lower propagation rates (-26% and -44%, respectively) and conjugated dienes formed (-17% and -25%, respectively) compared to the hamsters fed the high-linoleic sunflower oil. Relative to the high-linoleic sunflower oil, aortic cholesterol ester was reduced by -14% and -34% in the mid-oleic sunflower oil and high-oleic olive oil groups, respectively, with the latter reaching statistical significance. Although there were no significant associations between plasma lipids and lipoprotein cholesterol with aortic total cholesterol and cholesterol esters for any of the groups, the lag phase of conjugated diene formation was inversely associated with both aortic total and esterified cholesterol in the high-oleic olive oil-fed hamsters (r = -0.69, P < 0.05). The present study suggests that mid-oleic sunflower oil reduces risk factors such as lipoprotein cholesterol and oxidative stress associated with early atherosclerosis greater than the typical high-linoleic sunflower oil in hypercholesterolemic hamsters. The high-oleic olive oil not only significantly reduced oxidative stress but also reduced aortic cholesterol ester, a hallmark of early aortic atherosclerosis greater than the typical high-linoleic sunflower oil.

Experimental and interventional dietary study in humans on the role of HDL fatty acid composition in PGI2 release and Cox-2 expression by VSMC

BACKGROUND

High-density lipoproteins (HDLs) induce prostacyclin (PGI2) release in vascular smooth muscle cells (VSMCs) by up-regulation of cyclooxygenase-2 (Cox-2). Our goal was to analyze the role of human HDL lipid moiety on Cox-2-dependent PGI2 synthesis in human VSMCs and to assess the impact that the intake of diets with different fatty acid composition exert on HDL-induced PGI2 release.

MATERIALS AND METHODS

Human VSMCs were treated with HDL or fatty acids in the presence or absence of different cell signalling inhibitors and PGI2 (by enzyme immunoassay) and Cox-2 protein levels (by Western blot) were analyzed. High-density lipoproteins were obtained from a plasma pool or from plasma of 12 volunteers subjected to a longitudinal dietary interventional study of three consecutive diets periods enriched in monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids n-6 (PUFA n-6) or n-3 (PUFA n-3).

RESULTS

High-density lipoprotein delipidation attenuated the effect of HDL on both PGI2 synthesis and Cox-2 up-regulation, while arachidonic acid (AA) but not other fatty acids mimicked the effects of HDL. Arachidonic acid induced PGI2 synthesis and Cox-2 expression through similar mechanisms to those activated by HDL [pertussis toxin-sensitive G proteins, p42/44 mitogen-activated protein kinase (MAPK), p38MAPK, and c-Jun N-terminal kinase-1 (JNK-1) pathways]. Finally, we observed that HDL from the PUFA n-3 dietary period induced lower PGI2 release than that from the PUFA n-6 period (64% vs. 100%).

CONCLUSIONS

Our results suggest that lipid moiety modulates HDL-induced PGI2 release/Cox-2 up-regulation in human VSMCs, and that changes in fatty acids as accomplished with the diet can modulate vascular PGI2 homeostasis.

Dietary cis-monounsaturated fatty acids and metabolic control in type 2 diabetes

Whether low-fat, high-carbohydrate (CHO) diets or moderately high-fat, high-monounsaturated fatty acid (MUFA) diets are preferable for the treatment and prevention of diabetes has been a matter of debate. High-fat diets based on MUFA-rich oils or whole foods have been compared with high-CHO diets for effects on several cardiovascular risk outcomes in diabetic subjects. Early studies using metabolic diets with wide differences in total fat content (15-25% of energy) generally found a beneficial effect of MUFA diets on glycemic control and serum lipids. Recent studies using prescribed diets with a difference of </= 15% of energy in total fat between low-fat and high-MUFA diets show similar effects on glycemic profiles but still favor MUFA diets for effects on triacylglycerols and HDL cholesterol. It is unclear whether postprandial fat clearance is impaired by CHO diets and improved by MUFA diets, independent of effects on fasting triacylglycerol concentrations. Unless one diet contains abundant antioxidants, the 2 dietary approaches appear to have similar effects on LDL oxidation. Low-fat diets, however, are associated with atherogenic, dense LDL particles, while normal, buoyant LDL predominate with high-fat diets irrespective of fatty acid composition. Limited experimental evidence suggests that MUFA diets favorably influence blood pressure, coagulation, endothelial activation, inflammation, and thermogenic capacity. Energy-controlled high-MUFA diets do not promote weight gain and are more acceptable than low-fat diets for weight loss in obese subjects. Thus, there is good scientific support for MUFA diets as an alternative to low-fat diets for medical nutrition therapy in diabetes.

The degree of unsaturation of dietary fatty acids and the development of atherosclerosis (review)

Atherosclerosis is the principal contributor to the pathogenesis of myocardial and cerebral infarction, gangrene and loss of function in the extremities. It results from an excessive inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall. Atherosclerotic lesions develop fundamentally in three stages: dysfunction of the vascular endothelium, fatty streak formation and fibrous cap formation. Each stage is regulated by the action of vasoactive molecules, growth factors and cytokines. This multifactorial etiology can be modulated through the diet. The degree of unsaturation of dietary fatty acids affects lipoprotein composition as well as the expression of adhesion molecules and other pro-inflammatory factors, and the thrombogenicity associated with atherosclerosis development. Thus, the preventive effects of a monounsaturated-fatty acid-rich diet on atherosclerosis may be explained by the enhancement of high-density lipoprotein-cholesterol levels and the impairment of low-density lipoprotein-cholesterol levels, the low-density lipoprotein susceptibility to oxidation, cellular oxidative stress, thrombogenicity and atheroma plaque formation. On the other hand, the increase of high-density lipoprotein cholesterol levels and the reduction of thrombogenicity, atheroma plaque formation and vascular smooth muscle cell proliferation may account for the beneficial effects of polyunsaturated fatty acid on the prevention of atherosclerosis. Thus, the advantages of the Mediterranean diet rich in olive oil and fish on atherosclerosis may be due to the modulation of the cellular oxidative stress/antioxidant status, the modification of lipoproteins and the down-regulation of inflammatory mediators.

Protective effect of dietary monounsaturated fat on arteriosclerosis: beyond cholesterol

The consumption of diets enriched in monounsaturated fat has been related to a lower rate of coronary heart disease. It is well known that this dietary model decreases LDL-cholesterol plasma levels when replacing a saturated fat enriched diet. For this reason, a high monounsaturated fat diet is now being advocated to prevent cardiovascular disease, especially in Mediterranean countries. However, some expert panels-the Joint Task Force of European and other Societies on Coronary Prevention and the International Task Force for Prevention of Coronary Heart Disease-recommend replacing dietary saturated fat by complex carbohydrates, limiting the intake of total fat to <30% of the energy and monounsaturated fat to no more than 10-15% of total calories, reaching a similar effect on LDL-cholesterol plasma levels to a high monounsaturated fat diet. The most appropriate nutritional model to prevent arteriosclerosis should be supported by research into other biological effects of both diets. Therefore, it is interesting to review the non-lipid effect of monounsaturated fat, starting with its influence on other cardiovascular risk factors, such as carbohydrate metabolism and blood pressure. Moreover, substantial evidence of the effect of dietary monounsaturated fat on a wide range of healthy benefits beyond cholesterol, which have been investigated in recent years, such as lipoprotein oxidation, coagulation, fibrinolysis and endothelium, will be discussed. Furthermore, many observational epidemiological studies suggest that a high intake of monounsaturated fat is associated with reduced coronary risk and this will be analyzed in accordance with the clinical evidence to discuss the best dietary model to prevent coronary artery disease.

Changes in LDL particle composition after the consumption of meals containing different amounts and types of fat

BACKGROUND

Remodeling of lipoprotein particles in the postprandial period is considered to be an important source of atherogenic particles, but acute changes occurring after meals have been little studied.

OBJECTIVE

We sought to characterize changes in LDL particle composition occurring after a single meal, with particular reference to potential lipid exchange with particles carrying dietary fatty acids.

DESIGN

In a balanced design, 8 healthy subjects ingested isoenergetic meals of different fat content: low-fat, rich in saturated fatty acids (SFAs), and rich in polyunsaturated fatty acids (PUFAs). We investigated changes in LDL composition 4 and 6 h after meal ingestion.

RESULTS

The LDL triacylglycerol-to-protein ratio closely mirrored the plasma triacylglycerol concentrations after each of the meals, and there was a strong association between these variables in both the fasting and postprandial states (P < 0.001). A postprandial increase in LDL triacylglycerol was associated with a decrease in LDL cholesterol. There were no effects of the ingestion of a single meal on the LDL density profiles for protein or for any of the lipid components. The fatty acid composition of total LDL lipids changed in the postprandial period, with an enrichment in PUFA after the PUFA-rich meal and in SFA after the SFA-rich meal.

CONCLUSIONS

The changes observed in LDL composition after single meals are in accord with the proposition that there is neutral lipid exchange in the postprandial period, with triacylglycerol enrichment of LDL particles at the expense of cholesteryl esters. The change in the fatty acid composition of LDL particles implies significant lipid exchange with particles containing dietary fat.

Decreased aortic early atherosclerosis in hypercholesterolemic hamsters fed oleic acid-rich TriSun oil compared to linoleic acid-rich sunflower oil

Previous studies have demonstrated that low density lipoprotein (LDL) enriched in polyunsaturated fatty acids (PUFA) are more susceptible to oxidation (ex vivo) than those containing monounsaturated fatty acids (MUFA). To test whether this observation was associated with various parameters considered to be related with the development of early aortic atherosclerosis, hamsters were fed commercial hypercholesterolemic diets (HCD) containing either the PUFA, sunflower oil (SF) or the MUFA, TriSun oil (TS) at 10% with 0.4% cholesterol (wt/wt). LDL isolated from hamsters fed TS had significantly longer lag phase (30%, P < 0.05), a decreased propagation phase (-62%, P < 0.005), and fewer conjugated dienes formed (-37%, P < 0.007) compared to hamsters fed SF. Aortic vasomotor function, measured as degree of aortic relaxation, was significantly greater in the TS vs SF-fed hamsters whether acetylcholine or the calcium ionophore A23187 was used as the endothelium-dependent agonist. As a group, the SF-fed hamsters had significantly more early atherosclerosis than hamsters fed TS (46%, P < 0.006). When animals across the two diets were pair-matched by plasma LDL-C levels, there was an 82% greater mean difference (P < 0.002) in early atherosclerosis in the SF versus the TS-fed hamsters. While there were no significant associations with plasma lipids and lipoprotein cholesterol, early atherosclerosis was significantly correlated with lag phase (r = -0.67, p < 0.02), rate of LDL conjugated diene formation (r = 0.74, p < 0.006) and maximum dienes formed (r = 0.67, p < 0.02). Compared to TS-fed animals, aortic sections from hamsters fed the SF-containing diet revealed that the cytoplasm of numerous foam cells in the subendothelial space reacted positively with the monoclonal anti-bodies MDA-2 and NA59 antibody, epitopes found on oxidized forms of LDL. The present study suggests that compared to TS, hamsters fed the SF-diet demonstrated enhanced LDL oxidative susceptibility, reduced aortic relaxation, greater early aortic atherosclerosis and accumulation of epitopes found on oxidized forms of LDL.

Hypoglycemic, hypolipidemic and antioxidant properties of combination ofCurcumin fromCurcuma longa, Linn, and partially purified product fromAbroma augusta, Linn. in streptozotocin induced diabetes

Dietary spice components ofCurcuma longa andAbroma augusta have been screened for their protective effect against reactive oxygen species induced lipid peroxidation. They have been found to be efficient antioxidant when administered in combination. The purpose of the study was to investigate the effect of oral administration (300mg/Kg) of the aqueous extract of turmeric whose active ingredient isCurcumin andAbromine powder as a hypoglycemic agent mixed with diet. The effect of this aqueous extract on blood glucose, lipid peroxidation (LPO) and the antioxidant defense system in rat tissues like liver, lung, kidney and brain was studied for 8 weeks in streptozotocin induced diabetic rats. The administration of an aqueous extract of turmeric and abromine powder resulted in a significant reduction in blood glucose and an increase in total haemoglobin. The aqueous extract also resulted in decreased free radical formation in the tissues studied.The decrease in thiobarbituric acid reactive substances (TBARS) and increase in reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) clearly showed the antioxidant property of the mixture. It is suggested that these changes initially counteract the oxidative stress in diabetes however, a gradual decrease in the antioxidative process may be one of the factors which results in chronic diabetes. These results indicate that the mixture of the two plants have shown antidiabetic activity and also reduced oxidative stress in diabetes. A combination ofAbroma augusta and Curcuma longa also restored the other general parameters in diabetic animals. The results were statistically analyzed and indicated that combination of herbal extracts showed better efficacy as compared to individual herbal plant extracts used.

Inhibition of rat lipoprotein oxidation after tetradecylthioacetic acid feeding

We have previously shown that tetradecylthioacetic acid (TTA), a sulfur containing saturated fatty acid analogue, inhibits the oxidative modification of human low-density lipoprotein (LDL) in vitro. The oxidative modification of LDL is believed to be a crucial step in the progression of atherosclerosis. In the present study, we investigated the effect of TTA oral administration on the susceptibility of rat lipoprotein to undergo oxidative modification ex vivo. Lipoprotein resistance to copper-induced oxidation was highly improved after TTA administration to rats. Conjugated dienes produced after 150 min of lipoprotein oxidation were dramatically lowered in the TTA treated rats compared to controls. Malondialdehyde and lipid peroxides production by oxidation was highly limited. These effects were independent of any Vitamin E effects. More than 50% relative reduction in polyunsaturated fatty acids of the n-3 family, and more than 30% relative increase in 18:1n-9 fatty acid in the triacylglycerol (TAG)-rich lipoprotein were observed. TAG-rich lipoprotein lipids of TTA fed rats were decreased with more than 50% reduction in TAG. The data reported in this paper indicate a potent in vivo antioxidant capability of TTA that beside its hypolipidemic effect might be of importance in relation to the development of atherosclerosis.

Fatty acid saturation of the diet and plasma lipid concentrations, lipoprotein particle concentrations, and cholesterol efflux capacity

BACKGROUND

The fatty acid content and saturation degree of the diet can modulate HDL composition and cholesterol efflux.

OBJECTIVE

We studied the modifications in plasma lipoprotein particles and serum capacity to stimulate cholesterol efflux induced by different fatty acids.

DESIGN

Seventeen women and 24 men followed in the same sequence 4 diets containing 35% of total energy as fat. The saturated fat diet contained 17% palm oil; the monounsaturated fat diet, 20.9% olive oil; the n-6 polyunsaturated fat diet, 12.5% sunflower oil; and the n-3 polyunsaturated fat diet, sunflower oil supplemented with 4-4.5 g fish oil/d. Each phase lasted 4-5 wk.

RESULTS

In both sexes, apolipoprotein (apo) A-I concentrations were significantly lower with unsaturated fat diets than with the saturated fat diet, but concentrations of lipoproteins containing only apo A-I (Lp A-I) were lower only in the men. Concentrations of lipoproteins containing both apo A-I and apo A-II (Lp A-I:A-II) were lower with both polyunsaturated fat diets in the women but significantly higher in the men. Lp E concentrations were significantly higher with the 2 polyunsaturated fat diets. Lp E non-B particle concentrations were not modified in the men but were significantly higher in the women in both polyunsaturated fat phases. Lp C-III concentrations were higher with the saturated fat diet only in the men. The serum samples taken after the n-3 polyunsaturated fat phase were the most efficient for extracting cellular cholesterol in both sexes.

CONCLUSIONS

The monounsaturated and polyunsaturated fat diets were healthier, producing a better lipid profile. The n-3 polyunsaturated fat diet increased the capacity of serum to promote the efflux of cholesterol from cells in culture.

Effects of dietary fatty acids on the composition and oxidizability of low-density lipoprotein

OBJECTIVE

The objective of this study was to compare the effects of dietary monounsaturated fatty acids (MUFA), n-6 and n-3 polyunsaturated fatty acids (PUFA) on LDL composition and oxidizability.

DESIGN, SETTING AND SUBJECTS

Sixty-nine healthy young volunteers, students at a nearby college, were included. Six subjects withdrew because of intercurrent illness and five withdrew because they were unable to comply with the dietary regimen.

INTERVENTIONS

The participants received a 2-week wash-in diet rich in saturated fatty acids (SFA) followed by diets rich in refined olive oil, rapeseed oil or sunflower oil for 4 weeks. Intakes of vitamin E and other antioxidants did not differ significantly between the diets.

RESULTS

At the end of the study, LDL oxidizability was lowest in the olive oil group (lag time: 72.6 min), intermediate in the rapeseed oil group (68.2 min) and highest in the sunflower oil group (60.4 min, P<0.05 for comparison of all three groups). Despite wide variations in SFA intake, the SFA content of LDL was not statistically different between the four diets (25.8-28.5% of LDL fatty acids). By contrast, the PUFA (43.5%-60.5% of LDL fatty acids) and MUFA content of LDL (13.7-29.1% of LDL fatty acids) showed a wider variability dependent on diet.

CONCLUSIONS

Enrichment of LDL with MUFA reduces LDL susceptibility to oxidation. As seen on the rapeseed oil diet this effect is independent of a displacement of higher unsaturated fatty acids from LDL. Evidence from this diet also suggests that highly unsaturated n-3 fatty acids in moderate amounts do not increase LDL oxidizability when provided in the context of a diet rich in MUFA.

Low fat and high monounsaturated fat diets decrease human low density lipoprotein oxidative susceptibility in vitro

Oxidative modification of low density lipoprotein (LDL) is thought to play an important role in the development of atherosclerosis. Some studies have found that LDL enriched in monounsaturated fatty acids (MUFA) are less susceptible to oxidation than LDL enriched in polyunsaturated fatty acids (PUFA). A high MUFA diet is an alternative to a lower-fat blood cholesterol-lowering diet. Less is known about the effects of high MUFA versus lower-fat blood cholesterol-lowering diets on LDL oxidative susceptibility. The present study was designed to evaluate the effects of men and women consuming diets high in MUFA (peanuts plus peanut butter, peanut oil and olive oil) on LDL oxidative susceptibility, and to compare these effects with those of a Step II blood cholesterol-lowering diet. A randomized, double-blind, five-period crossover design (n = 20) was used to study the effects of the following diets on LDL-oxidation: average American [35% fat, 15% saturated fatty acids (SFA)], Step II (25% fat, 7% SFA), olive oil (35% fat, 7% SFA), peanut oil (35% fat, 7% SFA) and peanuts plus peanut butter (35% fat, 8% SFA). The average American diet resulted in the shortest lag time (57 +/- 6 min) for LDL oxidized ex vivo, whereas the Step II, olive oil and peanuts plus peanut butter diets resulted in a lag time of 66 +/- 6 min (P < or = 0.1). The slower rate of oxidation [nmol dienes/(min x mg LDL protein)] observed when subjects consumed the olive oil diet (24 +/- 2) versus the average American (28 +/- 2), peanut oil (28 +/- 2) and peanuts plus peanut butter diets (29 +/- 2; P < or = 0.05) was associated with a lower LDL PUFA content. The results of this study suggest that lower-fat and higher-fat blood cholesterol-lowering diets high in MUFA have similar effects on LDL oxidative resistance. In addition, our results suggest that different high MUFA sources varying in the ratio of MUFA to PUFA can be incorporated into a high MUFA diet without increasing the susceptibility of LDL to oxidation.