Novel aspects of postprandial lipemia in relation to atherosclerosis

Interplay of Postprandial Triglyceride-Rich Lipoprotein Composition and Adipokines in Obese Adolescents

In the context of the alarming rise of infant obesity and its health implications, the present research aims to uncover disruptions in postprandial lipid metabolism and the composition of triglyceride-rich lipoproteins in obese adolescents. A double-blind, controlled clinical trial in the postprandial phase on 23 adolescents aged 12 to 16 years was carried out. Twelve participants were categorized as obese (BMI > 30 kg/m2 and percentile > 95) and 11 as normal-weight (BMI = 20-25 kg/m2, percentile 5-85). Blood samples were collected after a 12-h overnight fast and postprandially after consumption of a standardized breakfast containing olive oil, tomato, bread, orange juice, and skimmed milk. Obese adolescents exhibited elevated triglyceride concentrations in both fasting and postprandial states and higher TG/apo-B48 ratios, indicating larger postprandial triglyceride-rich lipoprotein (TRL) particle size, which suggests impaired clearance. Obese subjects also exhibited higher n-6 PUFA concentrations, potentially linked to increased TRL hydrolysis and the release of pro-inflammatory adipokines. In contrast, TRL from normal-weight individuals showed higher concentrations of oleic acid and DHA (n-3 PUFA), with possible anti-inflammatory effects. The results indicate an interplay involving postprandial TRL metabolism and adipokines within the context of adolescent obesity, pointing to potential cardiovascular implications in the future.

Postprandial Metabolism and Vascular Function: Impact of Aging and Physical Activity Level

The consumption of a high-fat meal can induce postprandial lipemia and endothelial dysfunction. The authors assessed the impact of age and physical activity on metabolic and vascular outcomes following meal consumption in healthy adults. The authors recruited four groups: younger active (age 22.1 ± 1.4 years; n = 9), younger inactive (age 22.6 ± 3.7 years; n = 8), older active (age 68.4 ± 7.7 years; n = 8), and older inactive (age 67.7 ± 7.2 years; n = 7). The metabolic outcomes were measured at the baseline and hourly for 6 hr post high-fat meal consumption (12 kcal/kg; 63% fat). Flow-mediated dilation was measured at the baseline, 2 hr, and 4 hr postmeal. The total area under the curve for triglycerides was significantly lower in the more active groups, but did not differ based on age (younger active = 6.5 ± 1.4 mmol/L × 6 hr, younger inactive = 11.7 ± 4.8, older active = 6.8 ± 2.7, older inactive = 12.1 ± 1.7; p = .0004). After adjusting for artery diameter, flow-mediated dilation differed between groups at the baseline (younger active = 4.8 ± 1.6%, younger inactive = 2.5 ± 0.5, older active = 3.4 ± 0.9, older inactive = 2.2 ± 0.4; p < .001) and decreased significantly across groups 4 hr postmeal (mean difference = 0.82; 95% CI [0.02, 1.6]; p = .04). These findings highlight the beneficial effect of regular physical activity on postprandial lipemia, independent of age.

miRNA/Target Gene Profile of Endothelial Cells Treated with Human Triglyceride-Rich Lipoproteins Obtained after a High-Fat Meal with Extra-Virgin Olive Oil or Sunflower Oil

SCOPE

The effects of triglyceride-rich lipoproteins (TRLs) on the miRNA expression of endothelial cells, which are very involved in atherosclerosis, according to the type of diet are not known.

METHODS AND RESULTS

The differences between the effects of TRLs isolated from blood of subjects after a high-fat meal with extra-virgin olive oil (EVOO) and sunflower oil (SO) on the microRNA-Seq profile related to atherosclerosis in human umbilical vein endothelial cells are analyzed. 28 upregulated microRNAs with EVOO-derived TRLs, which can regulate 22 genes related to atherosclerosis, are found. 21 upregulated microRNAs with SO-derived TRLs, which can regulate 20 genes related to atherosclerosis, are found. These microRNAs are mainly involved in angiogenesis, with a predominance of an anti-angiogenic effect with EVOO-derived TRLs. Other microRNAs upregulated with SO-derived TRLs are involved in cardiovascular diseases. Pathways for the target genes obtained from the upregulated microRNA with EVOO-derived TRLs are involved in lipid metabolism and inflammatory and defense response, while those with SO-derived TRLs are involved in lipid metabolic process.

CONCLUSION

EVOO-derived TRLs seem to produce a more atheroprotective profile than SO-derived TRLs. This study provides alternative mechanisms on the protective role of EVOO against the atherogenic process through microRNA regulation in endothelial cells.

Policaptil Gel Retard Intake Reduces Postprandial Triglycerides, Ghrelin and Appetite in Obese Children: A Clinical Trial

The aim of this study is to test the hypothesis that the intake of Policaptil Gel Retard^® (PGR) is able to affect appetite, metabolic and hormonal postprandial profile in obese children. 46 obese children were randomly assigned to treatment with PGR or placebo, in a double blind clinical trial. Two PGR tablets or placebo were given in fasting condition, before the ingestion of a mixed meal (15 kcal/kg lean body mass). Blood samples were taken at baseline and for 4 hours, for measuring blood lipids, glucose, insulin, ghrelin, and glucagon like peptide-1 (GLP-1). Appetite was quantified using a visual analog scale. Children assuming PGR had a significantly lower increase of postprandial triglycerides (area under the curve (AUC): 3021 (2879) vs. 5038 (3738) mg × 240 min/Dl) and appetite (-234 (274) vs. 36 (329)) than children assuming placebo. The AUC of ghrelin was significantly lower after PGR ingestion, than after placebo (-8179 (8073) vs. -2800 (7579) pg × 240 min/mL). Blood glucose, insulin, non-esterified fatty acids (NEFA) and GLP-1 profiles were not significantly different in the two groups. In conclusion, a single intake of two tablets of PGR was associated with a significant reduction of appetite, ghrelin, and triglycerides in the postprandial period in obese children. Further investigation will assess if a chronic intake of PGR may affect body weight and glucose metabolism.

The Postprandial Appearance of Features of Cardiometabolic Risk: Acute Induction and Prevention by Nutrients and Other Dietary Substances

The purpose of this review is to provide an overview of diets, food, and food components that affect postprandial inflammation, endothelial function, and oxidative stress, which are related to cardiometabolic risk. A high-energy meal, rich in saturated fat and sugars, induces the transient appearance of a series of metabolic, signaling and physiological dysregulations or dysfunctions, including oxidative stress, low-grade inflammation, and endothelial dysfunction, which are directly related to the amplitude of postprandial plasma triglycerides and glucose. Low-grade inflammation and endothelial dysfunction are also known to cluster together with insulin resistance, a third risk factor for cardiovascular diseases (CVD) and type-II diabetes, thus making a considerable contribution to cardiometabolic risk. Because of the marked relevance of the postprandial model to nutritional pathophysiology, many studies have investigated whether adding various nutrients and other substances to such a challenge meal might mitigate the onset of these adverse effects. Some foods (e.g., nuts, berries, and citrus), nutrients (e.g., l-arginine), and other substances (various polyphenols) have been widely studied. Reports of favorable effects in the postprandial state have concerned plasma markers for systemic or vascular pro-inflammatory conditions, the activation of inflammatory pathways in plasma monocytes, vascular endothelial function (mostly assessed using physiological criteria), and postprandial oxidative stress. Although the literature is fragmented, this topic warrants further study using multiple endpoints and markers to investigate whether the interesting candidates identified might prevent or limit the postprandial appearance of critical features of cardiometabolic risk.

Orange juice modulates proinflammatory cytokines after high-fat saturated meal consumption

We aimed to evaluate the postprandial secretion of inflammatory markers induced by SFA or MUFA high-fat meal consumption and whether orange juice intake could modulate this induction. This study included 55 healthy women (aged 20 to 40 years): 33 participants received an SFA high-fat meal (≈1000 kcal, 37.6% of energy intake (E) from SFA) and 22 participants received an MUFA high-fat meal (≈1000 kcal, 56.3% E from MUFA). Both interventions were accompanied by 500 ml of orange juice (test) or water (control). The plasma concentrations of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α) and CRP were determined before (fasting) and 2, 3 and 5 hours after the test meal intake. The SFA high-fat meal induced a significant increase in AUC values (for TNF-α, IL-12, IL-10, IL-6 and IL-2 adjusted for baseline concentrations) in comparison with MUFA high-fat meal intervention. The results were independent of the drink which accompanied the meal (water or orange juice). Both IL-4 and IL-17A AUC values were significantly increased after an SFA high-fat meal intake, accompanied by water, but not by orange juice. In addition, these values were higher in relation to MUFA high-fat meal interventions. Also, IL-17A significantly increased at 3 h after an SFA high-fat meal intake accompanied by water, but not by orange juice. Overall, our conclusions indicate an anti-inflammatory effect of MUFA compared to SFA high-fat meal intake, while orange juice intake was able to mitigate the subclinical increase of postprandial inflammation, induced by SFA high-fat meal consumption, for a particular biomarker (IL-17A).

The repeatability of the abbreviated (4-h) Oral Fat Tolerance Test and influence of prior acute aerobic exercise

PURPOSE

The Oral Fat Tolerance Test (OFTT) is regarded as a repeatable measure used to assess postprandial triglyceride (TAG) levels, with higher levels observed in cardio-metabolic disorders. Acute aerobic exercise intervention before OFTT reduces the TAG response, but the repeatability of this effect is unknown. The aim of this study was to determine the repeatability of the abbreviated 4-h OFTT with and without immediate prior aerobic exercise.

METHODS

On four separate days, healthy adult male participants underwent two 4-h OFTT (n = 10) and another two 4-h OFTT with 1-h of standardised moderate intensity aerobic exercise performed immediately before meal ingestion (n = 11). The OFTT meal composition included 75.4 g total fat, 21.7 g carbohydrate and 13.7 g protein. Venous blood was sampled at baseline and hourly up to 4 h after the OFTT meal ingestion, and TAG area under the curve (AUC) was calculated.

RESULTS

Nonparametric Bland-Altman analysis of 4-h TAG AUC revealed that 9 of 10 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT. By contrast, two of 11 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT undertaken with 1-h prior aerobic exercise.

CONCLUSIONS

The 4-h OFTT is a repeatable test of postprandial TAG responses in healthy men. However, aerobic exercise performed immediately before OFTT considerably increases the variability of TAG AUC. These findings have implications for interpretation of research studies investigating exercise intervention performed immediately before OFTT. Future studies should also investigate the repeatability of exercise performed 8-24 h before OFTT.

Hypolipidemic effect of mannans from C. albicans serotypes a and B in acute hyperlipidemia in mice

Mannans, which are biological macromolecules of polysaccharide origin and function as immunomodulators, have been shown to stimulate macrophages in vivo by interaction with the mannose receptor. Thus, they can be used to stimulate macrophages in order to effectively remove circulating atherogenic lipoproteins. Our primary aim was to evaluate the hypolipidemic potential of mannans from C. albicans serotype A (mannan A) and serotype B (mannan B) in a murine model of hyperlipidemia. Mannan A and mannan B were shown to significantly (p<0.05) stimulate both the proliferation (p <0.05) and nitric oxide production of murine peritoneal macrophages in vitro. Pre-treatment of CBA/Lac mice with mannan A prior to induction of hyperlipidemia significantly (p<0.001) reduced serum atherogenic LDL-cholesterol, total cholesterol, and triglycerides. Mannan B exhibited a similar, but more potent, hypolipidemic effect. Electron microscopic analysis of liver revealed a significant (p<0.001) decrease in the volume of lipid droplets when hyperlipidemic mice were pretreated by both mannans. In conclusion, our findings would suggest that both polysaccharide-based biological macromolecules evaluated in the present study, specifically, the natural immunomodulators (mannans A and B), appeared to function as effective lipid-lowering macromolecules, which could potentially serve as adjunct therapy to more conventional hypolipidemic medications such as a statin drug.

Preventing cardiovascular heart disease: Promising nutraceutical and non-nutraceutical treatments for cholesterol management

Hypercholesterolemia is one of the major risk factors for the development of cardiovascular disease. Atherosclerosis resulting from hypercholesterolemia causes many serious cardiovascular diseases. Statins are generally accepted as a treatment of choice for lowering low-density lipoprotein (LDL) cholesterol, which reduces coronary heart disease morbidity and mortality. Since statin use can be associated with muscle problems and other adverse symptoms, non-adherence and discontinuation of statin therapy often leads to inadequate control of plasma cholesterol levels and increased cardiovascular risk. Moreover, there is compelling evidence on the presence of still considerable residual cardiovascular risk in statin-treated patients. Ezetimibe improves cholesterol-lowering efficacy and provides mild additional cardiovascular protection when combined with statin treatment. Despite a favorable safety profile compared to statins, ezetimibe-induced cholesterol-lowering is modest when used alone. Hence, there is a critical need to identity additional effective hypolipidemic agents that can be used either in combination with statins, or alone, if statins are not tolerated. Thus, hypolipidemic agents such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, apolipoprotein B-100 antisense oligonucleotides, cholesteryl ester transfer protein (CETP) inhibitors, and microsomal triglyceride transfer protein (MTTP) inhibitors, as well as yeast polysaccharides (beta-glucans and mannans) and compounds derived from natural sources (nutraceuticals) such as glucomannans, plant sterols, berberine, and red yeast rice are being used. In this review, we will discuss hypercholesterolemia, its impact on the development of cardiovascular disease (CVD), and the use of yeast polysaccharides, various nutraceuticals, and several therapeutic agents not derived from 'natural' sources, to treat hypercholesterolemia.

Vascular Disease Is Associated With the Expression of Genes for Intestinal Cholesterol Transport and Metabolism

CONTEXT

Intestinal cholesterol metabolism is important in influencing postprandial lipoprotein concentrations, and might be important in the development of vascular disease.

OBJECTIVE

This study evaluated associations between expression of intestinal cholesterol metabolism genes, postprandial lipid metabolism, and endothelial function/early vascular disease in human subjects.

DESIGN/PATIENTS

One hundred patients undergoing routine oesophago-gastro-duodenoscopy were recruited. mRNA levels of Nieman-Pick C1-like 1 protein (NPC1L1), ABC-G5, ABC-G8, ABC-A1, microsomal tissue transport protein (MTTP), and sterol-regulatory element-binding protein (SREBP)-2 were measured in duodenal biopsies using quantitative reverse transcription polymerase chain reaction. Postprandially, serum lipid and glycemic profiles were measured, endothelial function was assessed using fasting, and postprandial flow-mediated dilatation (FMD) and carotid intima-media thickness (IMT). Subjects were divided into those above and below the median value of relative expression of each gene, and results were compared between the groups.

RESULTS

There were no between-group differences in demographic variables or classical cardiovascular risks. For all genes, the postprandial triglyceride incremental area under the curve was greater (P < 0.05) in the group with greater expression. Postprandial apolipoprotein B48 (ApoB48) levels were greater (P < 0.05) in groups with greater expression of NPC1L1, ABC-G8, and SREBP-2. For all genes, postprandial but not fasting FMD was lower (P < 0.01) in the group with greater expression. Triglyceride and ApoB48 levels correlated significantly with postprandial FMD. Carotid artery IMT was greater (P < 0.05) in groups with greater expression of MTTP, ABC-A1, and SREBP-2.

CONCLUSION

Intestinal cholesterol metabolism gene expression is significantly associated with postprandial increment in triglycerides, intestinal ApoB48, and reduced postprandial FMD. Some genes were also associated with increased IMT. These findings suggest a role of intestinal cholesterol metabolism in development of early vascular disease.

A comparative study of the hypolipidaemic effects of a new polysaccharide, mannan Candida albicans serotype A, and atorvastatin in mice with poloxamer 407-induced hyperlipidaemia

Objectives

We evaluated the hypolipidaemic effect of mannan Candida albicans serotype A, relative to atorvastatin, in a mouse model of hyperlipidaemia.

Methods

Mannan serotype A was investigated in vitro and in vivo to determine its effects on macrophage proliferation, nitric oxide (NO) production by cultured macrophages, serum and liver lipids, changes in liver morphology and serum chitotriosidase activity and its expression in the liver.

Key findings

Mannan serotype A stimulates the macrophage proliferation and NO production in murine peritoneal macrophages in vitro. The activity of serum chitotriosidase (an enzyme released from the activated macrophages) was found to be significantly increased in P-407-induced hyperlipidaemic mice pretreated with low-dose mannan compared with mice administered P-407 only. Mannan treatment in mice was shown to significantly increase the chitotriosidase expression in the liver of both non-hyperlipidaemic and P-407-induced hyperlipidaemic mice. Lastly, mice pretreated with mannan before the induction of hyperlipidaemia with P-407 showed a significant reduction in the serum concentration of atherogenic LDL cholesterol, total cholesterol, triglycerides and liver triglycerides.

Conclusions

It is suggested that mannan serotype A, like β-glucan, may represent another hypolipidaemic agent, which could potentially be used as an adjunctive therapy with conventional antihyperlipidaemic drugs (statins and fibrates) in humans.

Nutrigenomics, the Microbiome, and Gene-Environment Interactions: New Directions in Cardiovascular Disease Research, Prevention, and Treatment: A Scientific Statement From the American Heart Association

Cardiometabolic diseases are the leading cause of death worldwide and are strongly linked to both genetic and nutritional factors. The field of nutrigenomics encompasses multiple approaches aimed at understanding the effects of diet on health or disease development, including nutrigenetic studies investigating the relationship between genetic variants and diet in modulating cardiometabolic risk, as well as the effects of dietary components on multiple "omic" measures, including transcriptomics, metabolomics, proteomics, lipidomics, epigenetic modifications, and the microbiome. Here, we describe the current state of the field of nutrigenomics with respect to cardiometabolic disease research and outline a direction for the integration of multiple omics techniques in future nutrigenomic studies aimed at understanding mechanisms and developing new therapeutic options for cardiometabolic disease treatment and prevention.

Casein Compared with Whey Proteins Affects the Organization of Dietary Fat during Digestion and Attenuates the Postprandial Triglyceride Response to a Mixed High-Fat Meal in Healthy, Overweight Men

BACKGROUND

Postprandial lipemia is a risk factor for cardiovascular disease. The potential impacts of the type/nature of dietary protein on postprandial lipemia and associated dysregulations have been insufficiently investigated.

OBJECTIVE

We investigated the postprandial effect of including in a high-fat meal some milk protein fractions that markedly differ in their physicochemical properties and composition [either casein (CAS), whey protein (WHE), or α-lactalbumin-enriched whey protein (LAC)].

METHODS

The protein fractions were incorporated as 15% energy in a high-fat meal in a 3-period, crossover postprandial study of 10 healthy overweight men with an elevated waist circumference (>94 cm). We measured postprandial changes in plasma lipids, amino acids, glucose, and oxidative stress markers, vascular function (using pulse contour analysis), and low-grade inflammation (using plasma markers). We also characterized in vitro the meal structures, including the size of the fat globule, and possible changes during digestion.

RESULTS

The type of protein did not affect postprandial plasma glucose, amino acids, insulin, or nonesterified fatty acids, but, compared with WHE and LAC, which did not differ, CAS markedly reduced postprandial triglycerides (TGs), achieving a 22 ± 10% reduction in the 6-h area under the curve (P < 0.05). Similar trends were shown for plasma chylomicrons [apolipoprotein (apo)B-48; P < 0.05]. However, there were no significant differences between the meals regarding postprandial oxidative stress (plasma hydroperoxides and malondialdehyde), endothelial dysfunction (salbutamol-induced changes in pulse contour analysis), or low-grade inflammation. In vitro studies showed that when the pH of the meal decreased to stomach pH values, the reduction in the solubility of casein resulted in a phase separation between fat and protein, whereas the proteins in the other meals remained suspended with fat globules.

CONCLUSION

In healthy overweight men, casein has specific physical interactions with fat that affect postprandial TGs, leading to the formation of fewer chylomicrons or an increase in chylomicron clearance. This trial was registered at clinicaltrials.gov as NCT00931151.

High fat challenges with different fatty acids affect distinct atherogenic gene expression pathways in immune cells from lean and obese subjects

SCOPE

Early perturbations in vascular health can be detected by imposing subjects to a high fat (HF) challenge and measure response capacity. Subtle responses can be determined by assessment of whole-genome transcriptional changes. We aimed to magnify differences in health by comparing gene-expression changes in peripheral blood mononuclear cells toward a high MUFA or saturated fatty acids (SFA) challenge between subjects with different cardiovascular disease risk profiles and to identify fatty acid specific gene-expression pathways.

METHODS AND RESULTS

In a cross-over study, 17 lean and 15 obese men (50-70 years) received two 95 g fat shakes, high in SFAs or MUFAs. Peripheral blood mononuclear cell gene-expression profiles were assessed fasted and 4-h postprandially. Comparisons were made between groups and shakes. During fasting, 294 genes were significantly differently expressed between lean and obese. The challenge increased differences to 607 genes after SFA and 2516 genes after MUFA. In both groups, SFA decreased expression of cholesterol biosynthesis and uptake genes and increased cholesterol efflux genes. MUFA increased inflammatory genes and PPAR-α targets involved in β-oxidation.

CONCLUSION

Based upon gene-expression changes, we conclude that an HF challenge magnifies differences in health, especially after MUFA. Our findings also demonstrate how SFAs and MUFAs exert distinct effects on lipid handling pathways in immune cells.

Proteome from patients with metabolic syndrome is regulated by quantity and quality of dietary lipids

BACKGROUND

Metabolic syndrome is a multi-component disorder associated to a high risk of cardiovascular disease. Its etiology is the result of a complex interaction between genetic and environmental factors, including dietary habits. We aimed to identify the target proteins modulated by the long-term consumption of four diets differing in the quality and quantity of lipids in the whole proteome of peripheral blood mononuclear cells (PBMC).

RESULTS

A randomized, controlled trial conducted within the LIPGENE study assigned 24 MetS patients for 12 weeks each to 1 of 4 diets: a) high-saturated fatty acid (HSFA), b) high-monounsaturated fatty acid (HMUFA), c) low-fat, high-complex carbohydrate diets supplemented with placebo (LFHCC) and d) low-fat, high-complex carbohydrate diets supplemented with long chain (LC) n-3 polyunsaturated fatty acids (PUFA) (LFHCC n-3). We analyzed the changes induced in the proteome of both nuclear and cytoplasmic fractions of PBMC using 2-D proteomic analysis. Sixty-seven proteins were differentially expressed after the long-term consumption of the four diets. The HSFA diet induced the expression of proteins responding to oxidative stress, degradation of ubiquitinated proteins and DNA repair. However, HMUFA, LFHCC and LFHCC n-3 diets down-regulated pro-inflammatory and oxidative stress-related proteins and DNA repairing proteins.

CONCLUSION

The long-term consumption of HSFA, compared to HMUFA, LFHCC and LFHCC n-3, seems to increase the cardiovascular disease (CVD) risk factors associated with metabolic syndrome, such as inflammation and oxidative stress, and seem lead to DNA damage as a consequence of high oxidative stress.

Apolipoprotein E genotype has a modest impact on the postprandial plasma response to meals of varying fat composition in healthy men in a randomized controlled trial

BACKGROUND

Apolioprotein E (APOE) genotype is reported to influence a person's fasting lipid profile and potentially the response to dietary fat manipulation. The impact of APOE genotype on the responsiveness to meals of varying fat composition is unknown.

OBJECTIVE

We examined the effect of meals containing 50 g of fat rich in saturated fatty acids (SFAs), unsaturated fatty acids (UNSATs), or SFAs with fish oil (SFA-FO) on postprandial lipemia.

METHOD

A randomized, controlled, test meal study was performed in men recruited according to the APOE genotype (n = 10 APOE3/3, n = 11 APOE3/E4).

RESULTS

For the serum apoE response (meal × genotype interaction P = 0.038), concentrations were on average 8% lower after the UNSAT than the SFA-FO meal in APOE4 carriers (P = 0.015) only. In the genotype groups combined, there was a delay in the time to reach maximum triacylglycerol (TG) concentration (mean ± SEM: 313 ± 25 vs. 266 ± 27 min) and higher maximum nonesterified fatty acid (0.73 ± 0.05 vs. 0.60 ± 0.03 mmol/L) and glucose (7.92 ± 0.22 vs. 7.25 ± 0.22 mmol/L) concentrations after the SFA than the UNSAT meal, respectively (P ≤ 0.05). In the Svedberg flotation rate 60-400 TG-rich lipoprotein fraction, meal × genotype interactions were observed for incremental area under the curve (IAUC) for the TG (P = 0.038) and apoE (P = 0.016) responses with a 58% lower apoE IAUC after the UNSAT than the SFA meal (P = 0.017) in the E4 carriers.

CONCLUSIONS

Our data indicate that APOE genotype had a modest impact on the postprandial response to meals of varying fat composition in normolipidemic men. The physiologic importance of greater apoE concentrations after the SFA-rich meals in APOE4 carriers may reflect an impact on TG-rich lipoprotein clearance from the circulation. This trial was registered at clinicaltrials.gov as NCT01522482.

Hypertriglyceridemia influences the degree of postprandial lipemic response in patients with metabolic syndrome and coronary artery disease: from the CORDIOPREV study

Objective

To determine whether metabolic syndrome traits influence the postprandial lipemia response of coronary patients, and whether this influence depends on the number of MetS criteria.

Materials and Methods

1002 coronary artery disease patients from the CORDIOPREV study were submitted to an oral fat load test meal with 0.7 g fat/kg body weight (12% saturated fatty acids, 10% polyunsaturated fatty acids, 43% monounsaturated fatty acids), 10% protein and 25% carbohydrates. Serial blood test analyzing lipid fractions were drawn at 0, 1, 2, 3 and 4 hours during the postprandial state. Total and incremental area under the curves of the different postprandial parameters were calculated following the trapezoid rule to assess the magnitude of change during the postprandial state

Results

Postprandial lipemia response was directly related to the presence of metabolic syndrome. We found a positive association between the number of metabolic syndrome criteria and the response of postprandial plasma triglycerides (p<0.001), area under the curve of triglycerides (p<0.001) and incremental area under the curve of triglycerides (p<0.001). However, the influence of them on postprandial triglycerides remained statistically significant only in those patients without basal hypertriglyceridemia. Interestingly, in stepwise multiple linear regression analysis with the AUC of triglycerides as the dependent variable, only fasting triglycerides, fasting glucose and waist circumference appeared as significant independent (P<0.05) contributors. The multiple lineal regression (R) was 0.77, and fasting triglycerides showed the greatest effect on AUC of triglycerides with a standardized coefficient of 0.75.

Conclusions

Fasting triglycerides are the major contributors to the postprandial triglycerides levels. MetS influences the postprandial response of lipids in patients with coronary heart disease, particularly in non-hypertriglyceridemic patients.

Taste hedonics influence the disposition of fat by modulating gastric emptying in rats

We investigated how preferred and nonpreferred tastes influence the disposition of fat. Adult male Sprague Dawley rats were infused with 5 ml of 20% intralipid through an intragastric catheter and with 0.3 ml of a taste solution through an intraoral catheter. At 120 min postinfusion, plasma concentrations of fat fuels (triglycerides and non-esterified fatty acids) were either unchanged or slightly higher after rats tasted a preferred sweet taste solution (0.125% saccharin +3% glucose) than after they tasted water. They were markedly lower after rats tasted a non-preferred solution–either a bitter solution (0.15% quinine hydrochloride) or a sweet solution that had previously been the conditioned stimulus for lithium-induced taste aversion. The distribution of ¹⁴C-triolein mixed with the gastric load was determined at 4 h postinfusion. Rats that received a non-preferred bitter taste had significantly more ¹⁴C remaining in the stomach than did those that received a preferred sweet taste. These results suggest that taste hedonics–either unconditioned or conditioned aversive tastes–influence fat disposition by altering gastric emptying.

Association between postprandial triglycerides and coronary artery disease detected by coronary computed tomography angiography

BACKGROUND

Studies have demonstrated the association of severe anatomical coronary artery disease (CAD) with postprandial triglycerides (TG) concentrations. Nevertheless the relationship between less severe atherosclerosis plaque burden and postprandial TG is less established.

OBJECTIVE

to study the relationship between postprandial TG and CAD detected by coronary computed tomographic angiography (CTA).

MATERIAL AND METHODS

130 patients who underwent an oral fat tolerance test were enrolled (85 with CAD detected by CTA and 45 without). Postprandial lipemia was studied by measuring TG from T0h to T6h with 2-h intervals, and analyzed the TG change over time using a longitudinal multivariable linear mixed effects model with the log normal of the TG as the primary outcome.

RESULTS

The majority of individuals with CAD had non-obstructive disease (63.3%) Patients with CAD had a slower clearance of postprandial TG change from 4 h to 6 h (p<0.05) compared to patients without CAD. These results remained significant after adjustment for fasting TG and glucose, age, gender, body mass index, and waist circumference. However, those differences did not reach statistical significance after adjustment for fasting HDL-C.

CONCLUSION

Patients with mild (<25% lumen obstruction) and moderate CAD (25-50% lumen obstruction) detected by coronary CTA had an impaired postprandial metabolism, with a delayed TG clearance, when compared to individuals with no CAD. This difference was partially explained by the lower HDL-C. Thus, though postprandial TG may contribute to the development of CAD, this association is partially related to low HDL-C.

Effects of the n-6/n-3 polyunsaturated fatty acids ratio on postprandial metabolism in hypertriacylglycerolemia patients

Background

Atherosclerosis is a postprandial phenomenon. The balanced n-6/n-3 PUFA ratio contributing to the prevention of atherosclerosis has been well shown, but the effect of the ratio on postprandial metabolism has not been fully investigated. The aim of this study was to investigate the effects of the n-6/n-3 PUFAs ratio on postprandial metabolism in hypertriacylglycerolemia patients, comparing them to healthy controls.

Methods

Test meals with 0.97 (high n-3) and 8.80 (low n-3) n-6/n-3 PUFAs ratio were administered in a randomized crossover design to 8 healthy and 8 hypertriacylglycerolemia subjects. Blood samples were collected for 8 hours after meals to measure triglyceride (TG), total cholesterol (TC), HDL, ApoA, ApoB, glucose, insulin, inflammatory makers including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), endothelial function including nitric oxide (NO) and endothelin-1 (ET-1).

Results

According to repeated–measures ANOVA, the postprandial response of lipid, glucose, insulin, inflammation and endothelial function were not significantly different between meals. The postprandial TG and NO response were significantly different between healthy control (HC) and hypertriglyceridemia group (HTG) after both meals (P < 0.01). After both meals maximal change and iAUC for TG was all higher in HTG group than HC group, the difference was significant after low n-3 meal but not after high n-3 meal. The concentration of glucose, insulin, IL-6, TNFα and ET-1 at each time point was higher and NO was lower in HTG group, but the maximal change and iAUC had no significant difference except for iAUC of insulin, IL-6 and diAUC of NO after low n-3 meal.

Conclusions

The ratio of n-6 and n-3 maybe do not acutely influence the postprandial metabolism, inflammatory response and endothelial function, but the low n-3 meal can strengthen the difference between HTG and HC group.

Chronic supplementation of proanthocyanidins reduces postprandial lipemia and liver miR-33a and miR-122 levels in a dose-dependent manner in healthy rats

Elevated postprandial triglycerides are associated with an increased risk of cardiovascular disease. Acute proanthocyanidin supplementation improves postprandial lipemia. Therefore, in this study, we evaluated whether a chronic treatment (3 weeks) of grape seed proanthocyanidins (GSPE) improves tolerance to lipid overload and represses liver microRNA (miRNA)-33a and miRNA-122 and their target genes as a mechanism to soften the elevated postprandial triglycerides in healthy rats. Additionally, the minimal GSPE chronic dose required to alter miRNA levels was determined by means of a dose-response experiment using 5, 15, 25 or 50 mg of GSPE/kg body weight. GSPE repressed miR-33a and miR-122 liver expression and reduced postprandial lipemia in a dose-dependent manner. Significant effects were only observed at high levels of proanthocyanidin consumption, but moderate doses of proanthocyanidins were still able to modulate miRNA expression. Therefore, it can be suggested that a population with a normal intake of proanthocyanidin-rich foods can benefit from the modulation of miRNA expression. At the molecular level, this action can confer homeostatic robustness and will thus exert subtle changes in lipid metabolism, thereby reducing the risk associated with postprandial hyperlipemia.

Regulating intestinal function to reduce atherogenic lipoproteins

Significant knowledge regarding different molecules involved in the transport of dietary fat into the circulation has been garnered. Studies point to the possibility that accumulation of intestine-derived lipoproteins in the plasma could contribute to atherosclerosis. This article provides a brief overview of dietary lipid metabolism and studies in mice supporting the hypothesis that intestinal lipoproteins contribute to atherosclerosis. Deficiencies in lipoprotein lipase and Gpihbp1, and overexpression of heparanse in mice, are associated with increases in atherosclerosis, suggesting that defects in catabolism of larger lipoproteins in the plasma contribute to atherosclerosis. Furthermore, inositol-requiring enzyme 1β-deficient mice that produce more intestinal lipoproteins also develop more atherosclerosis. Thus, increases in plasma intestinal lipoproteins due to either overproduction or reduced catabolism result in augmented atherosclerosis. Intestinal lipoproteins tend to adhere strongly to subendothelial proteoglycans, elicit an inflammatory response by endothelial cells and activate macrophages, contributing to the initiation and progression of the disease. Thus, molecules that reduce intestinal lipid absorption can be useful in lowering atherosclerosis.

A high-fat SFA, MUFA, or n3 PUFA challenge affects the vascular response and initiates an activated state of cellular adherence in lean and obese middle-aged men

BMI and fatty acid type affect postprandial metabolic TG responses, but whether these factors also affect vascular, inflammatory, and leukocyte adherence responses remains unclear. We therefore compared those postprandial responses between lean and obese men after 3 high-fat challenges differing in fatty acid composition. In a crossover double-blind study, 18 lean (BMI: 18-25 kg/m(2)) and 18 obese (BMI >29 kg/m(2)) middle-aged men received 3 isocaloric high-fat milkshakes containing 95 g fat (88% of energy), either high in SFAs (54% of energy/total fat), MUFAs (83% of energy/total fat), or n3 (omega-3) PUFAs (40% of energy/total fat). Hemodynamics, augmentation index (AIX), leukocyte cell surface adhesion markers, and plasma cytokines involved in vascular adherence, coagulation, and inflammation were measured before and after consumption of the milkshakes. In both groups and after all shakes were consumed, AIX decreased; plasma soluble intercellular adhesion molecule (sICAM) 1, sICAM3, soluble vascular cell adhesion molecule (sVCAM) 1, and interleukin-8 increased; monocyte CD11a, CD11b, and CD621 expression increased; neutrophil CD11a, CD11b, and CD621 expression increased; and lymphocyte CD62l expression increased (P < 0.05). Lymphocyte CD11a and CD11b expression decreased in lean participants after consumption of all shakes but did not change in obese participants (P < 0.05). Obese participants had a less pronounced decrease in heart rate after the consumption of all shakes (P < 0.05). MUFA consumption induced a more pronounced decrease in blood pressure and AIX compared with the other milkshakes in both lean and obese participants (P < 0.05). High-fat consumption initiates an activated state of cellular adherence and an atherogenic milieu. This response was independent of fatty acid type consumed or of being lean or obese, despite the clear differences in postprandial TG responses between the groups and different milkshakes. These findings suggest that in addition to increased TGs, other mechanisms are involved in the high-fat consumption-induced activated state of cellular adherence.

p38 MAPK protects human monocytes from postprandial triglyceride-rich lipoprotein-induced toxicity

Postprandial triglyceride (TG)-rich lipoproteins (TRLs) transport dietary fatty acids through the circulatory system to satisfy the energy and structural needs of the tissues. However, fatty acids are also able to modulate gene expression and/or induce cell death. We investigated the underlying mechanism by which postprandial TRLs of different fatty acid compositions can induce cell death in human monocytes. Three types of dietary fat [refined olive oil (ROO), high-palmitic sunflower oil (HPSO), and butter] with progressively increasing SFA:MUFA ratios (0.18, 0.41, and 2.08, respectively) were used as a source of postprandial TRLs (TRL-ROO, TRL-HPSO, and TRL-BUTTER) from healthy men. The monocytic cell line THP-1 was used as a model for this study. We demonstrated that postprandial TRLs increased intracellular lipid accumulation (31-106%), reactive oxygen species production (268-349%), DNA damage (133-1467%), poly(ADP-ribose) polymerase 1 (800-1710%) and caspase-3 (696-1244%) activities, and phosphorylation of c-Jun NH2-terminal kinase (JNK) (54 kDa, 141-288%) and p38 (24-92%). These effects were significantly greater with TRL-BUTTER, and TRL-ROO did not induce DNA damage, DNA fragmentation, or p38 phosphorylation. In addition, blockade of p38, but not of JNK, significantly decreased intracellular lipid accumulation and increased cell death in postprandial TRL-treated cells. These results suggest that in human monocytes, p38 is involved in survival signaling pathways that protect against the lipid-mediated cytotoxicity induced by postprandial TRLs that are abundant in saturated fatty acids.

Dyslipidemia in obesity: mechanisms and potential targets

Obesity has become a major worldwide health problem. In every single country in the world, the incidence of obesity is rising continuously and therefore, the associated morbidity, mortality and both medical and economical costs are expected to increase as well. The majority of these complications are related to co-morbid conditions that include coronary artery disease, hypertension, type 2 diabetes mellitus, respiratory disorders and dyslipidemia. Obesity increases cardiovascular risk through risk factors such as increased fasting plasma triglycerides, high LDL cholesterol, low HDL cholesterol, elevated blood glucose and insulin levels and high blood pressure. Novel lipid dependent, metabolic risk factors associated to obesity are the presence of the small dense LDL phenotype, postprandial hyperlipidemia with accumulation of atherogenic remnants and hepatic overproduction of apoB containing lipoproteins. All these lipid abnormalities are typical features of the metabolic syndrome and may be associated to a pro-inflammatory gradient which in part may originate in the adipose tissue itself and directly affect the endothelium. An important link between obesity, the metabolic syndrome and dyslipidemia, seems to be the development of insulin resistance in peripheral tissues leading to an enhanced hepatic flux of fatty acids from dietary sources, intravascular lipolysis and from adipose tissue resistant to the antilipolytic effects of insulin. The current review will focus on these aspects of lipid metabolism in obesity and potential interventions to treat the obesity related dyslipidemia.

The influence of weight excess on the postprandial lipemia in adolescents

BACKGROUND

Postprandial lipemia (PL) in adults has been extensively studied, but little explored in youth. The aim of this study was to evaluate the influence of weight excess on postprandial lipemia in adolescents.

METHODS

Eighty-three adolescents were classified into Groups 1 (n= 49, overweight) and 2 (n=34, eutrophic). Total cholesterol (TC), triglycerides (TG), HDL and LDL cholesterol were measured before, 2 and 4 hours after a standardized 25 g lipid and 25 g of carbohydrate test meal; glycemia and insulin measured only at baseline. Anthropometric evaluation was performed.

RESULTS

Basal TG were higher in Group 1 (p= 0.022). The total increase (Δ-TG), corresponding to the difference between the maximum and the basal TG level was similar in both groups (29.8 ± 21.5 mg/dl vs. 28.2 ± 24.5 mg/dl, p= 0.762). TC, HDL and LDL did not change significantly throughout the test. By analyzing all the adolescents together, the waist circumference was positively correlated with TG at fasting (r = 0.223; p= 0.044) and at 4 hours (r = 0.261; p= 0.019). Only overweight adolescents with hypertriglyceridemia, who also had higher HOMA-IR, presented significant elevation of TG levels 2 and 4 hours after the overload.

CONCLUSION

The behavior of lipoproteins in the post-prandial state is similar in eutrophic and overweight adolescents. Thus, apparently the weight excess does not induce post prandial lipemic alterations.

Within-person variation in the postprandial lipemic response of healthy adults

BACKGROUND

The response to dietary fat plays a key role in metabolic health. Although this can vary widely between individuals, variation within an individual and the associated contribution of phenotypic and genotypic factors to this variation are less defined.

OBJECTIVES

The objectives were to quantify within-person variation in triacylglycerol response by means of a novel variation score (S(v)) and to explore the phenotypic and genotypic factors associated with this score.

DESIGN

Two consecutive 5-h oral-lipid-tolerance tests (OLTTs) were conducted in 51 healthy adults aged 18-60 y with a BMI (in kg/m²) of 18.5 to 49.8. Detailed body composition, physical function, biochemistry, and genotype data were gathered.

RESULTS

The postprandial triacylglycerol response profile did not differ (P = 0.64) across OLTTs for the group; nor did average concentrations of functional markers apolipoprotein C2 (P = 0.73) and apolipoprotein C3 (P = 0.74). S(v) was low in most (82%) of the adults and was significantly (P < 0.05) associated with age, fasting triacylglycerol, triacylglycerol AUC, and fasting nonessential fatty acids. Significant associations were also observed between S(v) and single nucleotide polymorphisms in 7 genes (APOA1, IL1α, IL1β, TLR4, TCF7L2, CCK1Rec, and STAT3) after correction for phenotypic differences.

CONCLUSIONS

This work showed that the within-person variability in postprandial lipemic response is low in most healthy adults. It also showed that variability in this response is associated with a defined set of phenotypic and genotypic characteristics.

Pro-atherogenic postprandial profile: meal-induced changes of lipoprotein sub-fractions and inflammation markers in obese boys

BACKGROUND AND AIMS

Obesity is a pro-atherogenic condition and postprandial lipoprotein profile and circulating cytokines changes may contribute to promote the process. The aim of this study is to investigate postprandial metabolic response, lipoprotein oxidation and circulating cytokine levels, after the ingestion of two different meals with different fat/carbohydrate ratio.

METHODS AND RESULTS

Ten prepubertal obese boys consumed two meals with the same energy and protein content but with a different carbohydrate to fat ratio: 1) moderate fat (MF): 61% carbohydrate, 27% fat; 2) high fat (HF): 37% carbohydrate, 52% fat. The AUC of glucose and insulin were significantly (p < 0.05) lower after the HF meal. HF meal was followed by a significant decrease in the cholesterol carried in the HDL fractions, while cholesterol in the small, dense LDL and in the VLDL particles increased, as compared to baseline (p < 0.05 for all). No differences were found in the cholesterol distribution after the MF meal. Moreover, HDL-C concentration was lower (p < 0.05) at 300 min after HF vs. MF meal. Oxidized LDL (ox-LDL) concentration increased after the HF meal but not after the MF meal [9.3(2.2) vs 1.8(2.2)% from baseline, P < 0.02)]. A positive association (r > 0.3, P < 0.05) was observed between the densest LDL particles and the ox-LDL plasma levels. A reduction of IL-6 was found at 120 min after the MF [-23.3(5.5) vs -8.4(3.8)% from baseline, P < 0.05)] compared with the HF meal.

CONCLUSION

A simple change of ≈25% of energy load from fat to carbohydrate in a meal significantly improves postprandial pro-atherogenic factors in obese boys.

Atherosclerosis and physical activity

Atherosclerosis and coronary heart disease have been considered as major health problem worldwide. Abnormalities in lipids and lipoprotein metabolism and impairment of endothelial function have been implicated as the main contributing factors in atherosclerosis and its progression. Physical activity has been recognized as a preventive measure for atherosclerosis.

Increased intestinal lipid absorption caused by Ire1β deficiency contributes to hyperlipidemia and atherosclerosis in apolipoprotein E-deficient mice

RATIONALE

High fasting serum lipid levels are significant risk factors for atherosclerosis. However, the contributions of postprandial excursions in serum lipoproteins to atherogenesis are less well-characterized.

OBJECTIVE

This study aims to delineate whether changes in intestinal lipid absorption associated with loss of inositol-requiring enzyme 1β (Ire1β) would affect the development of hyperlipidemia and atherosclerosis in Apoe(-/-) mice.

METHODS AND RESULTS

We used Ire1β-deficient mice to assess the contribution of intestinal lipid absorption to atherosclerosis. Here, we show that Ire1b(-/-)/Apoe(-/-) mice contain higher levels of intestinal microsomal triglyceride transfer protein, absorb more lipids, exhibit hyperlipidemia, and have higher levels of atherosclerotic plaques compared with Apoe(-/-) mice when fed chow and western diets.

CONCLUSIONS

These studies indicate that Ire1β regulates intestinal lipid absorption and that increased intestinal lipoprotein production contributes to atherosclerosis.

Absence of acute inhibitory effect of insulin on chylomicron production in type 2 diabetes

OBJECTIVE

Overproduction of intestinally derived apoB-48-containing triglyceride-rich lipoproteins (TRLs) (chylomicrons) has recently been described in type 2 diabetes, as is known for hepatic TRL-apoB-100 (very-low-density lipoprotein) production. Furthermore, insulin acutely inhibits both intestinal and hepatic TRL production, whereas this acute inhibitory effect on very-low-density lipoprotein production is blunted in type 2 diabetes. It is not currently known whether this acute effect on chylomicron production is similarly blunted in humans with type 2 diabetes.

METHODS AND RESULTS

We investigated the effect of acute hyperinsulinemia on TRL metabolism in 18 type 2 diabetic men using stable isotope methodology. Each subject underwent 1 control (saline infusion [SAL]) lipoprotein turnover study followed by a second study, under 1 of the 3 following clamp conditions: (1) hyperinsulinemic-euglycemic, (2) hyperinsulinemic-hyperglycemic, or (3) hyperinsulinemic-euglycemic plus intralipid and heparin. TRL-apoB-48 and TRL-apoB-100 production and clearance rates were not different between SAL and clamp and between the different clamp conditions, except for significantly lower TRL-apoB-100 clearance and production rates in hyperinsulinemic-euglycemic plus intralipid and heparin clamp compared with SAL.

CONCLUSIONS

This is the first demonstration in individuals with type 2 diabetes that chylomicron production is resistant to the normal acute suppressive effect of insulin. This phenomenon may contribute to the highly prevalent dyslipidemia of type 2 diabetes and potentially to atherosclerosis. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00950209.

Effects of 3-month Mediterranean-type diet on postprandial TAG and apolipoprotein B48 in the Medi-RIVAGE cohort

Objective

To determine the postprandial lipaemia response before and after intervention with healthy diets in the Medi-RIVAGE cohort of subjects with moderate risk factors of CVD.

Design

One hundred and thirty-five adults (fifty-two men and eighty-three women) followed either a Mediterranean-type (MED) diet or a low-fat American Heart Association-type diet in a parallel design for 3 months. At entry and after 3 months, lipids, glucose and insulin were measured in the fasting samples; TAG and apolipoprotein B48 (ApoB48; a marker of intestinally derived chylomicrons) levels were measured in the fasting and postprandial samples after a standard test meal.

Results

The MED diet only lowered (P< 0·028) fasting TAG and both diets reduced TAG and ApoB48 levels 5 h after the test meal. The overall 5 h postprandial ApoB48 response (area under curve (AUC)/incremental AUC) was lowered after both diets but this effect was more marked after the MED-diet intervention. Whatever the TAG level at entry, normo- and hyper TAG subjects showed a reduction in the postprandial ApoB48 levels after 3-month diets. BMI at entry did not impact the effect of diets given subjects with BMI < or >25 kg/m2showed reduced postprandial ApoB48. Men and women displayed comparable postprandial changes after dietary challenges.

Conclusions

A MED diet appears efficient to improve postprandial lipaemia, a recently acknowledged CVD risk, in men and women at moderate cardiovascular risk.

[Postprandial lipemia induces endothelial dysfunction and higher insulin resistance in healthy subjects]

OBJECTIVE

To assess the effect of postprandial lipemia on endothelial function, insulin resistance, and lipid profile in healthy subjects.

PATIENTS AND METHODS

A prospective', interventional study in 14 healthy young men aged 18-25 years who were given a high-fat meal. Endothelial function was measured using flow-mediated dilation (FMD) in the brachial artery, flow velocity, mean arterial pressure and serum nitrite/nitrate levels (NO(2)/NO(3)). Glucose, insulin, total cholesterol, and triglyceride levels were also tested. Insulin resistance was determined by calculating the HOMA-IR index (Homeostatic Model Assessment-Insulin Resistance).

RESULTS

Baseline FMD was 5.9 ± 1.1%. Postprandial lipemia reduced endothelial function by approximately 50% in the first (3.3 ± 0.5%, p=0.03) and second (3.3 ± 0.4%, p=0.04) moment respectively. This finding was associated to an increased flow rate in the brachial artery and lower NO(2)/NO(3) levels (p<0.05). Higher cholesterol and triglyceride levels were found 1h and 2h postprandial (p<0.05). HOMA-IR was significantly increased 1h and 2h postprandial (p<0.05).

CONCLUSIONS

Postprandial lipemia causes changes in circulating lipid profile and induces endothelial dysfunction and higher insulin resistance.

A sodium-bicarbonated mineral water reduces gallbladder emptying and postprandial lipaemia: a randomised four-way crossover study

BACKGROUND

Sodium-bicarbonated mineral waters are reported to have beneficial digestive and hypocholesterolaemic properties. The aim of the study was to investigate the effects of consumption of a sodium-bicarbonated mineral water (BW) with or without a meal, compared to a low mineral content water as the control water (CW), on postprandial serum triacylglycerols (TAG), cholecystokinin (CCK) and gallbladder volume.

METHODS

The study design was a four-way randomised controlled crossover trial. Healthy adult men and women (>18 and <40 years, TAG <2.82 mmol/L) consumed 0.5 L of CW + standard meal; 0.5 L of BW + standard meal; and 0.5 L of CW without meal or 0.5 L of BW without meal.

RESULTS

BW consumed without meal had no significant effect on the study parameters compared to CW. However, BW with meal induced a lower concentration of serum TAG at 30 min (p = 0.01) and 60 min (p = 0.03) postprandial times, lower CCK concentrations at 30 min (p = 0.002), and higher gallbladder volume at 30 min (p = 0.03), 60 min (p = 0.01) and 120 min (p = 0.04). Gallbladder ejection fraction was lower with the BW (p = 0.03), whilst area under the curve and peak contraction amplitude (lowest gallbladder volume) were higher (p = 0.01, p = 0.02, respectively) compared to the CW.

CONCLUSION

Consumption of BW with a meal induces lower levels of CCK and reduces gallbladder emptying and postprandial TAG levels. It is proposed that this sodium-bicarbonated mineral water could be used as part of the habitual diet by the general population in order to reduce cardiovascular risk.

Hypertriglyceridemia, Metabolic Syndrome, and Cardiovascular Disease in HIV-Infected Patients: Effects of Antiretroviral Therapy and Adipose Tissue Distribution

The use of combination antiretroviral therapy (CART) in HIV-infected patients has resulted in a dramatic decline in AIDS-related mortality. However, mortality due to non-AIDS conditions, particularly cardiovascular disease (CVD) seems to increase in this population. CART has been associated with several metabolic risk factors, including insulin resistance, low HDL-cholesterol, hypertriglyceridemia and postprandial hyperlipidemia. In addition, HIV itself, as well as specific antiretroviral agents, may further increase cardiovascular risk by interfering with endothelial function. As the HIV population is aging, CVD may become an increasingly growing health problem in the future. Therefore, early diagnosis and treatment of cardiovascular risk factors is warranted in this population. This paper reviews the contribution of both, HIV infection and CART, to insulin resistance, postprandial hyperlipidemia and cardiovascular risk in HIV-infected patients. Strategies to reduce cardiovascular risk are also discussed.

Postprandial lipid responses to an alpha-linolenic acid-rich oil, olive oil and butter in women: a randomized crossover trial

Background

Postprandial lipaemia varies with gender and the composition of dietary fat due to the partitioning of fatty acids between beta-oxidation and incorporation into triacylglycerols (TAGs). Increasing evidence highlights the importance of postprandial measurements to evaluate atherogenic risk. Postprandial effects of alpha-linolenic acid (ALA) in women are poorly characterized. We therefore studied the postprandial lipid response of women to an ALA-rich oil in comparison with olive oil and butter, and characterized the fatty acid composition of total lipids, TAGs, and non-esterified fatty acids (NEFAs) in plasma.

Methods

A randomized crossover design (n = 19) was used to compare the postprandial effects of 3 meals containing 35 g fat. Blood samples were collected at regular intervals for 7 h. Statistical analysis was carried out with ANOVA (significant difference = P < 0.05).

Results

No significant difference was seen in incremental area under the curve (iAUC) plasma-TAG between the meals. ALA and oleic acid levels were significantly increased in plasma after ALA-rich oil and olive oil meals, respectively. Palmitic acid was significantly increased in plasma-TAG after the butter meal. The ratios of 18:2 n-6 to18:3 n-3 in plasma-TAGs, three and seven hours after the ALA-rich oil meal, were 1.5 and 2.4, respectively. The corresponding values after the olive oil meal were: 13.8 and 16.9; and after the butter meal: 9.0 and 11.6.

Conclusions

The postprandial p-TAG and NEFA response in healthy pre-menopausal women was not significantly different after the intake of an ALA-rich oil, olive oil and butter. The ALA-rich oil significantly affected different plasma lipid fractions and improved the ratio of n-6 to n-3 fatty acids several hours postprandially.

Triacylglycerol-rich lipoproteins derived from healthy donors fed different olive oils modulate cytokine secretion and cyclooxygenase-2 expression in macrophages: the potential role of oleanolic acid

PURPOSE

Current evidence suggests that consumption of virgin olive oil (VOO) helps to protect against the development of atherosclerosis and that minor components such as oleanolic acid contribute to this effect. In this study, the effects of triacylglycerol-rich lipoproteins (TRLs) derived from olive oil on inflammatory processes in macrophages and how they are modulated by oleanolic acid was investigated.

METHODS

TRLs isolated from healthy volunteers 2 and 4 h after a test meal containing VOO, pomace olive oil (POO) (the second pressing of olive oil, enriched in minor components) or POO enriched with oleanolic acid (OPOO) were incubated with macrophages derived from the human monocyte cell line, THP-1.

RESULTS

All types of TRLs caused a decrease of about 50% in the secretion of monocyte chemoattractant protein-1 (MCP-1) by the cells. Interleukin (IL)-6 secretion was also significantly decreased by 2 and 4 h VOO TRLs and by 4 h OPOO TRLs. In contrast, increased IL-1β secretion was observed with all 2 h TRL types, and increased tumour necrosis factor-α (TNF-α) production with 2 h VOO and POO, but not OPOO, TRLs. TRLs isolated after 4 h, however, had no significant effects on TNF-α secretion and increased IL-1β secretion only when they were derived from VOO. Cyclooxygenase-2 (COX-2) mRNA expression was strongly down-regulated by all types of TRLs, but protein expression was significantly depressed only by 4 h OPOO TRLs.

CONCLUSION

These findings demonstrate that TRLs derived from olive oil influence inflammatory processes in macrophages and suggest that oleanolic acid may have beneficial effects.