Extra-virgin olive oil consumption reduces the age-related decrease in HDL and paraoxonase 1 anti-inflammatory activities.

Paraoxonase 1 (PON1) is associated with HDL and modulates the antioxidant and anti-inflammatory role of HDL. The goals of the present study were to investigate the effect of ageing and the role of PON1 on the anti-inflammatory activity of HDL, and to determine whether extra-virgin olive oil (EVOO) consumption could improve the atheroprotective activity of HDL. HDL and PON1 were isolated from the plasma of ten young (Y-HDL and Y-PON1) and ten elderly (E-HDL and E-PON1) healthy volunteers before and after 12 weeks of EVOO consumption. Inflammation was assessed by measuring intracellular adhesion molecule 1 (ICAM-1) expression. THP-1 (human acute monocytic leukaemia cell line) monocyte chemotaxis was measured using a Boyden chamber. Oxidative damage to HDL was assessed by measuring conjugated diene formation and changes in electrophoretic migration. Y-HDL had more anti-inflammatory activity than E-HDL. The conjugated diene content and the electrophoretic mobility of E-HDL were higher than those of Y-HDL. Y-PON1 had significant anti-inflammatory activity, reducing ICAM-1 expression by 32·64 (SD 2·63)%, while E-PON1 had no significant effect. THP-1 chemotaxis measurements confirmed the ICAM-1 expression results. The 12 weeks of EVOO consumption significantly increased the anti-inflammatory activities of both HDL and PON1. The anti-inflammatory activity of HDL was modulated by PON1 and was lower in the elderly volunteers. EVOO consumption increased the anti-inflammatory effect of HDL and reduced the age-related decrease in anti-atherogenic activity.

Extra-virgin olive oil consumption improves the capacity of HDL to mediate cholesterol efflux and increases ABCA1 and ABCG1 expression in human macrophages.

The present study was aimed to investigate the effect of 12 weeks of extra-virgin olive oil (EVOO) consumption on the capacity of HDL to promote cholesterol efflux (CE) and to determine which CE pathways are modulated by EVOO consumption. Whole HDL and HDL2/HDL3 subclasses were isolated from the plasma of twenty-six healthy volunteers before and after 12 weeks of EVOO consumption (25 ml/d). EVOO consumption increased the capacity of serum and HDL to mediate CE from THP-1, J774 macrophages and Fu5AH cells by 9·8-24·57 %, depending on the cell type. The increase in CE was independent of both HDL concentration and subclass distribution. The three HDL-mediated CE pathways (ATP-binding cassette (ABC) A1, ABCG1 and scavenger receptor class B type I (SR-BI)) were modulated by EVOO consumption. The fluidity of the phospholipidic layer of HDL increased by 13 % (P< 0·001) following EVOO consumption compared with baseline. EVOO consumption also increased the release of excess cholesterol from human monocyte-derived macrophages (HMDM) by 44 % (P< 0·001), and ABCA1 and ABCG1 mRNA transcription by 16·08 % (P< 0·001) and 35·79 % (P< 0·01), respectively. The protein expression of these two cholesterol transporters also increased after EVOO consumption. In contrast, SR-BI mRNA and protein expression in HMDM were significantly lower after 12 weeks of EVOO consumption. Incubating J774 macrophages with EVOO polyphenol extracts induced a concentration-dependent up-regulation of ABCA1 and ABCG1 expression in macrophages. After 12 weeks of EVOO consumption, the capacity of HDL to mediate CE was improved and the ability of HMDM to release excess cholesterol was enhanced by increasing the expression of ABCA1 and ABCG1 transporters.

Gene-nutrient interactions on the phosphoenolpyruvate carboxykinase influence insulin sensitivity in metabolic syndrome subjects.

BACKGROUND & AIMS: Genetic background may interact with habitual dietary fat composition, and affect development of the metabolic syndrome (MetS). The phosphoenolpyruvate carboxykinase gene (PCK1) plays a significant role regulating glucose metabolism, and fatty acids are key metabolic regulators, which interact with transcription factors and influence glucose metabolism. We explored genetic variability at the PCK1 gene locus in relation to degree of insulin resistance and plasma fatty acid levels in MetS subjects. Moreover, we analyzed the PCK1 gene expression in the adipose tissue of a subgroup of MetS subjects according to the PCK1 genetic variants. METHODS: Insulin sensitivity, insulin secretion, glucose effectiveness, plasma concentrations of C-peptide, fatty acid composition and three PCK1 tag-single nucleotide polymorphisms (SNPs) were determined in 443 MetS participants in the LIPGENE cohort. RESULTS: The rs2179706 SNP interacted with plasma concentration of n - 3 polyunsaturated fatty acids (n - 3 PUFA), which were significantly associated with plasma concentrations of fasting insulin, peptide C, and HOMA-IR. Among subjects with n - 3 PUFA levels above the population median, carriers of the C/C genotype exhibited lower plasma concentrations of fasting insulin (P = 0.036) and HOMA-IR (P = 0.019) as compared with C/C carriers with n - 3 PUFA below the median. Moreover, homozygous C/C subjects with n - 3 PUFA levels above the median showed lower plasma concentrations of peptide C as compared to individuals with the T-allele (P = 0.006). Subjects carrying the T-allele showed a lower gene PCK1 expression as compared with carriers of the C/C genotype (P = 0.015). CONCLUSIONS: The PCK1 rs2179706 polymorphism interacts with plasma concentration of n - 3 PUFA levels modulating insulin resistance in MetS subjects.

Insulin receptor substrate-2 gene variants in subjects with metabolic syndrome: association with plasma monounsaturated and n-3 polyunsaturated fatty acid levels and insulin resistance.

SCOPE: Several insulin receptor substrate-2 (IRS-2) polymorphisms have been studied in relation to insulin resistance and type 2 diabetes. To examine whether the genetic variability at the IRS-2 gene locus was associated with the degree of insulin resistance and plasma fatty acid levels in metabolic syndrome (MetS) subjects. METHODS AND RESULTS: Insulin sensitivity, insulin secretion, glucose effectiveness, plasma fatty acid composition and three IRS-2 tag-single nucleotide polymorphisms (SNPs) were determined in 452 MetS subjects. Among subjects with the lowest level of monounsaturated (MUFA) (below the median), the rs2289046 A/A genotype was associated with lower glucose effectiveness (p<0.038), higher fasting insulin concentrations (p<0.028) and higher HOMA IR (p<0.038) as compared to subjects carrying the minor G-allele (A/G and G/G). In contrast, among subjects with the highest level of MUFA (above the median), the A/A genotype was associated with lower fasting insulin concentrations and HOMA-IR, whereas individuals carrying the G allele and with the highest level of ω-3 polyunsaturated fatty acids (above the median) showed lower fasting insulin (p<0.01) and HOMA-IR (p<0.02) as compared with A/A subjects. CONCLUSION: The rs2289046 polymorphism at the IRS2 gene locus may influence insulin sensitivity by interacting with certain plasma fatty acids in MetS subjects.

Glucokinase regulatory protein genetic variant interacts with omega-3 PUFA to influence insulin resistance and inflammation in metabolic syndrome.

UNLABELLED: Glucokinase Regulatory Protein (GCKR) plays a central role regulating both hepatic triglyceride and glucose metabolism. Fatty acids are key metabolic regulators, which interact with genetic factors and influence glucose metabolism and other metabolic traits. Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been of considerable interest, due to their potential to reduce metabolic syndrome (MetS) risk. OBJECTIVE: To examine whether genetic variability at the GCKR gene locus was associated with the degree of insulin resistance, plasma concentrations of C-reactive protein (CRP) and n-3 PUFA in MetS subjects. DESIGN: Homeostasis model assessment of insulin resistance (HOMA-IR), HOMA-B, plasma concentrations of C-peptide, CRP, fatty acid composition and the GCKR rs1260326-P446L polymorphism, were determined in a cross-sectional analysis of 379 subjects with MetS participating in the LIPGENE dietary cohort. RESULTS: Among subjects with n-3 PUFA levels below the population median, carriers of the common C/C genotype had higher plasma concentrations of fasting insulin (P = 0.019), C-peptide (P = 0.004), HOMA-IR (P = 0.008) and CRP (P = 0.032) as compared with subjects carrying the minor T-allele (Leu446). In contrast, homozygous C/C carriers with n-3 PUFA levels above the median showed lower plasma concentrations of fasting insulin, peptide C, HOMA-IR and CRP, as compared with individuals with the T-allele. CONCLUSIONS: We have demonstrated a significant interaction between the GCKR rs1260326-P446L polymorphism and plasma n-3 PUFA levels modulating insulin resistance and inflammatory markers in MetS subjects. Further studies are needed to confirm this gene-diet interaction in the general population and whether targeted dietary recommendations can prevent MetS in genetically susceptible individuals. TRIAL REGISTRATION: ClinicalTrials.gov NCT00429195.

Effects of dietary fat modification on oxidative stress and inflammatory markers in the LIPGENE study.

Subjects with the metabolic syndrome (MetS) have enhanced oxidative stress and inflammation. Dietary fat quality has been proposed to be implicated in these conditions. We investigated the impact of four diets distinct in fat quantity and quality on 8-iso-PGF2α (a major F2-isoprostane and oxidative stress indicator), 15-keto-13,14-dihydro-PGF2α (15-keto-dihydro-PGF2α, a major PGF2α metabolite and marker of cyclooxygenase-mediated inflammation) and C-reactive protein (CRP). In a 12-week parallel multicentre dietary intervention study (LIPGENE), 417 volunteers with the MetS were randomly assigned to one of the four diets: two high-fat diets (38 % energy (%E)) rich in SFA or MUFA and two low-fat high-complex carbohydrate diets (28 %E) with (LFHCC n-3) or without (LFHCC) 1·24 g/d of very long chain n-3 fatty acid supplementation. Urinary levels of 8-iso-PGF2α and 15-keto-dihydro-PGF2α were determined by RIA and adjusted for urinary creatinine levels. Serum concentration of CRP was measured by ELISA. Neither concentrations of 8-iso-PGF2α and 15-keto-dihydro-PGF2α nor those of CRP differed between diet groups at baseline (P>0·07) or at the end of the study (P>0·44). Also, no differences in changes of the markers were observed between the diet groups (8-iso-PGF2α, P = 0·83; 15-keto-dihydro-PGF2α, P = 0·45; and CRP, P = 0·97). In conclusion, a 12-week dietary fat modification did not affect the investigated markers of oxidative stress and inflammation among subjects with the MetS in the LIPGENE study.

NOS3 gene polymorphisms are associated with risk markers of cardiovascular disease, and interact with omega-3 polyunsaturated fatty acids.

OBJECTIVE: Omega-3 polyunsaturated fatty acids (n-3 PUFA) may protect against the development of cardiovascular disease (CVD). Genotype at key genes such as nitric oxide synthase (NOS3) may determine responsiveness to fatty acids. Gene-nutrient interactions may be important in modulating the development of CVD, particularly in high-risk individuals with the metabolic syndrome (MetS). METHODS: Biomarkers of CVD risk, plasma fatty acid composition, and NOS3 single nucleotide polymorphism (SNP) genotype (rs11771443, rs1800783, rs1800779, rs1799983, rs3918227, and rs743507) were determined in 450 individuals with the MetS from the LIPGENE dietary intervention cohort. The effect of dietary fat modification for 12 weeks on metabolic indices of the MetS was determined to understand potential NOS3 gene-nutrient interactions. RESULTS: Several markers of inflammation and dyslipidaemia were significantly different between the genotype groups. A significant gene-nutrient interaction was observed between the NOS3 rs1799983 SNP and plasma n-3 PUFA status on plasma triacylglycerol (TAG) concentrations. Minor allele carriers (AC+AA) showed an inverse association with significantly higher plasma TAG concentrations in those with low plasma n-3 PUFA status and vice versa but the major allele homozygotes (CC) did not. Following n-3 PUFA supplementation, plasma TAG concentrations of minor allele carriers of rs1799983 were considerably more responsive to changes in plasma n-3 PUFA, than major allele homozygotes. CONCLUSIONS: Carriers of the minor allele at rs1799983 in NOS3 have plasma TAG concentrations which are more responsive to n-3 PUFA. This suggests that these individuals might show greater beneficial effects of n-3 PUFA consumption to reduce plasma TAG concentrations.

Dietary fat modifications and blood pressure in subjects with the metabolic syndrome in the LIPGENE dietary intervention study.

Hypertension is a key feature of the metabolic syndrome. Lifestyle and dietary changes may affect blood pressure (BP), but the knowledge of the effects of dietary fat modification in subjects with the metabolic syndrome is limited. The objective of the present study was to investigate the effect of an isoenergetic change in the quantity and quality of dietary fat on BP in subjects with the metabolic syndrome. In a 12-week European multi-centre, parallel, randomised controlled dietary intervention trial (LIPGENE), 486 subjects were assigned to one of the four diets distinct in fat quantity and quality: two high-fat diets rich in saturated fat or monounsaturated fat and two low-fat, high-complex carbohydrate diets with or without 1.2 g/d of very long-chain n-3 PUFA supplementation. There were no overall differences in systolic BP (SBP), diastolic BP or pulse pressure (PP) between the dietary groups after the intervention. The high-fat diet rich in saturated fat had minor unfavourable effects on SBP and PP in males.

Gene-nutrient interactions in the metabolic syndrome: single nucleotide polymorphisms in ADIPOQ and ADIPOR1 interact with plasma saturated fatty acids to modulate insulin resistance.

BACKGROUND: Progression of the metabolic syndrome (MetS) is determined by genetic and environmental factors. Gene-environment interactions may be important in modulating the susceptibility to the development of MetS traits. OBJECTIVE: Gene-nutrient interactions were examined in MetS subjects to determine interactions between single nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and its receptors (ADIPOR1 and ADIPOR2) and plasma fatty acid composition and their effects on MetS characteristics. DESIGN: Plasma fatty acid composition, insulin sensitivity, plasma adiponectin and lipid concentrations, and ADIPOQ, ADIPOR1, and ADIPOR2 SNP genotypes were determined in a cross-sectional analysis of 451 subjects with the MetS who participated in the LIPGENE (Diet, Genomics, and the Metabolic Syndrome: an Integrated Nutrition, Agro-food, Social, and Economic Analysis) dietary intervention study and were repeated in 1754 subjects from the LIPGENE-SU.VI.MAX (SUpplementation en VItamines et Minéraux AntioXydants) case-control study (http://www.ucd.ie/lipgene). RESULTS: Single SNP effects were detected in the cohort. Triacylglycerols, nonesterified fatty acids, and waist circumference were significantly different between genotypes for 2 SNPs (rs266729 in ADIPOQ and rs10920533 in ADIPOR1). Minor allele homozygotes for both of these SNPs were identified as having degrees of insulin resistance, as measured by the homeostasis model assessment of insulin resistance, that were highly responsive to differences in plasma saturated fatty acids (SFAs). The SFA-dependent association between ADIPOR1 rs10920533 and insulin resistance was replicated in cases with MetS from a separate independent study, which was an association not present in controls. CONCLUSIONS: A reduction in plasma SFAs could be expected to lower insulin resistance in MetS subjects who are minor allele carriers of rs266729 in ADIPOQ and rs10920533 in ADIPOR1. Personalized dietary advice to decrease SFA consumption in these individuals may be recommended as a possible therapeutic measure to improve insulin sensitivity. This trial was registered at clinicaltrials.gov as NCT00429195.

I-FABP expression alters the intracellular distribution of the BODIPY C16 fatty acid analog.

To investigate the structure-function relationships of intestinal fatty acid-binding protein (I-FABP) in cellular fatty acid (FA) trafficking, we compared the distribution of a fluorescent FA analog (BODIPY FL C16) in Cos-1 cells transiently transfected with the wild type protein (wt I-FABP) to that of a variant deleted of the alpha helical domain (HL I-FABP). In vector-only cells, BODIPY fluorescence was distributed throughout the cytoplasm. In the absence of added FA, wt I-FABP was found largely in the perinuclear region with some cytoplasmic staining as well. Addition of BODIPY FL C16 to transfected cells showed that the fluorescent FA was essentially completely colocalized with the protein in the cytoplasmic and perinuclear regions as well as in cytoplasmic clusters that are not observed in the absence of wt I-FABP. For HL I-FABP, the distribution of the protein in the absence of FA was diffusely cytoplasmic, in marked contrast to the wt protein. Addition of BODIPY led to less extensive colocalization than that observed for wt I-FABP. In particular, no localization to the perinuclear region was found. Organelle colocalization studies showed that both proteins colocalized with mitochondria and endoplasmic reticulum/golgi markers, but little with a lysosomal marker. The perinuclear localization for wt I-FABP and BODIPY did not show colocalization with any of the markers tested. Taken together, these results indicate that I-FABP binds FA in vivo and that the helical domain may be important for targeting I-FABP to a perinuclear domain but not, perhaps, to the endoplasmic reticulum, golgi apparatus or mitochondria.

LIPGENE food-exchange model for alteration of dietary fat quantity and quality in free-living participants from eight European countries.

Controlled human intervention trials are required to confirm the hypothesis that dietary fat quality may influence insulin action. The aim was to develop a food-exchange model, suitable for use in free-living volunteers, to investigate the effects of four experimental diets distinct in fat quantity and quality: high SFA (HSFA); high MUFA (HMUFA) and two low-fat (LF) diets, one supplemented with 1.24 g EPA and DHA/d (LFn-3). A theoretical food-exchange model was developed. The average quantity of exchangeable fat was calculated as the sum of fat provided by added fats (spreads and oils), milk, cheese, biscuits, cakes, buns and pastries using data from the National Diet and Nutrition Survey of UK adults. Most of the exchangeable fat was replaced by specifically designed study foods. Also critical to the model was the use of carbohydrate exchanges to ensure the diets were isoenergetic. Volunteers from eight centres across Europe completed the dietary intervention. Results indicated that compositional targets were largely achieved with significant differences in fat quantity between the high-fat diets (39.9 (sem 0.6) and 38.9 (sem 0.51) percentage energy (%E) from fat for the HSFA and HMUFA diets respectively) and the low-fat diets (29.6 (sem 0.6) and 29.1 (sem 0.5) %E from fat for the LF and LFn-3 diets respectively) and fat quality (17.5 (sem 0.3) and 10.4 (sem 0.2) %E from SFA and 12.7 (sem 0.3) and 18.7 (sem 0.4) %E MUFA for the HSFA and HMUFA diets respectively). In conclusion, a robust, flexible food-exchange model was developed and implemented successfully in the LIPGENE dietary intervention trial.