Cardiovascular disease is a chronic disease influenced by many factors, with activated blood platelets being one of them. Platelets play a central role in the formation of plaques within blood vessels, contributing to early inflammatory events. Consumption of diets rich in plant-based products protects against the development of cardiovascular disease. Polyphenols, which are secondary plant metabolites found in a wide range of foodstuffs and beverages, may be partially responsible for these effects. Their protective properties include inhibitory effects on platelet function in vitro and in vivo. However, the bioavailability of many polyphenols is poor and it is unclear whether sufficient quantities can be obtained by dietary means to exert protective effects. Consequently, this review summarizes 25 well-controlled human intervention studies examining the effect of polyphenol-rich diets on platelet function. These studies report a huge variety of research methods, study designs, and study subjects, resulting in controversial assertions. One consistent finding is that cocoa-related products, however, have platelet-inhibiting effects when consumed in moderate amounts. To assess whether other classes of dietary polyphenols, or their metabolites, also beneficially affect platelet function requires more well-controlled intervention studies as well as the adoption of more uniform methods to assess platelet aggregation and activation.

The use of computational modeling and simulation has increased in many biological fields, but despite their potential these techniques are only marginally applied in nutritional sciences. Nevertheless, recent applications of modeling have been instrumental in answering important nutritional questions from the cellular up to the physiological levels. Capturing the complexity of today's important nutritional research questions poses a challenge for modeling to become truly integrative in the consideration and interpretation of experimental data at widely differing scales of space and time. In this review, we discuss a selection of available modeling approaches and applications relevant for nutrition. We then put these models into perspective by categorizing them according to their space and time domain. Through this categorization process, we identified a dearth of models that consider processes occurring between the microscopic and macroscopic scale. We propose a "middle-out" strategy to develop the required full-scale, multilevel computational models. Exhaustive and accurate phenotyping, the use of the virtual patient concept, and the development of biomarkers from "-omics" signatures are identified as key elements of a successful systems biology modeling approach in nutrition research-one that integrates physiological mechanisms and data at multiple space and time scales.

BACKGROUND: Animal studies suggest that dietary cis-9,trans-11 (c9,t11) conjugated linoleic acid (CLA) may inhibit or regress the development of atherosclerosis. The effect of CLA on atherosclerosis has not been assessed in humans. OBJECTIVE: We investigated the effect of c9,t11 CLA supplementation on aortic pulse wave velocity (a marker of atherosclerosis) and on cardiovascular risk factors in overweight and obese but otherwise apparently healthy subjects. DESIGN: In a double-blind, randomized, placebo-controlled, parallel-group trial, we randomly assigned 401 subjects, aged 40-70 y and with a body mass index (in kg/m(2))>/= 25, to receive either 4 g CLA/d (2.5 g c9,t11 CLA/d and 0.6 g trans-10,cis-12 CLA/d) or placebo supplements for 6 mo. Aortic pulse wave velocity, blood pressure, anthropometric characteristics, and concentrations of fasting lipid, glucose, insulin, and C-reactive protein measured before and after supplementation. RESULTS: During the intervention, mean (+/-SE) pulse wave velocity did not change in the c9,t11 CLA group (Delta0.00 +/- 0.07) compared with the placebo group (Delta0.09 +/- 0.06). There was no effect of c9,t11 CLA supplementation on blood pressure, body composition, insulin resistance, or concentrations of lipid, glucose, and C-reactive protein. CONCLUSION: This study does not support an antiatherosclerotic effect or an effect on cardiovascular risk factors of c9,t11 CLA. This trial was registered at www.clinicaltrials.gov as NCT00706745.

Baukje de Roos is a principal investigator at the University of Aberdeen, Rowett Institute of Nutrition and Health. She investigates mechanisms through which dietary fats and fatty acids, and also polyphenols, affect parameters involved in the development of heart disease in vivo. This is achieved not only by measuring their effect on conventional risk markers for heart disease but also by assessing their effect on new markers that are being developed through proteomic and mass spectrometry methods. She obtained her PhD in Human Nutrition at Wageningen University, The Netherlands, in January 2000, after which she was appointed as a post-doctoral research fellow at the Department of Vascular Biochemistry, Glasgow Royal Infirmary, in collaboration with GlaxoSmithKline. In June 2001 she joined the Rowett Research Institute in Aberdeen. She is currently working for the University of Aberdeen, where her research is funded by the Scottish Government Rural and Environment Research and Analysis Directorate (RERAD). She is an active member of the European Nutrigenomics Organisation (NuGO), an EU-funded Network of Excellence, which merges the nutrigenomics activities of its 23 partners across Europe.

Long-chain n-3 PUFA from fish oil protect against death from CHD but mechanisms are not well understood. Preliminary results indicate that fish oil may affect the enzyme soluble epoxide hydrolase (sEH) and influence inflammatory pathways in a time-dependent manner. In the present study male apoE knockout (Apoe-/-) mice were randomised to three dietary groups receiving a high-fat high-cholesterol diet supplemented with 2 %(w/w) high-oleic acid sunflower-seed (HOSF) oil, DHA oil or fish oil. Livers and proximal aortas were collected on day 2 and on weeks 1, 2, 4 and 10 to determine hepatic sEH levels, hepatic fatty acid composition, hepatic proteome and atherosclerotic plaque size in the aortic root. Intervention with fish oil, but not with DHA, resulted in significantly lower levels of hepatic sEH levels with time compared with HOSF oil. DHA and fish oil caused differential regulation of thirty-five hepatic proteins which were mainly involved in lipoprotein metabolism and oxidative stress. All mice developed atherosclerosis without differences in plaque size between the three groups. Thus EPA may be responsible for lowering levels of hepatic sEH and both fish oil and DHA could beneficially affect lipoprotein metabolism and oxidative stress.

The development of insulin resistance in the obese is associated with chronic, low-grade inflammation. We aimed to identify novel links between obesity, insulin resistance and the inflammatory response by comparing C57BL/6 with type I interleukin-1 receptor knockout (IL-1RI(-/-)) mice, which are protected against diet-induced insulin resistance. Mice were fed a high-fat diet for 16 wk. Insulin sensitivity was measured and proteomic analysis was performed on adipose, hepatic and skeletal muscle tissues. Despite an equal weight gain, IL-1RI(-/-) mice had lower plasma glucose, insulin and triacylglycerol concentrations, compared with controls, following dietary treatment. The higher insulin sensitivity in IL-1RI(-/-) mice was associated with down-regulation of antioxidant proteins and proteasomes in adipose tissue and hepatic soluble epoxide hydrolase, consistent with a compromised inflammatory response as well as increased glycolysis and decreased fatty acid beta-oxidation in their muscle. Their lower hepatic triacylglycerol concentrations may reflect decreased flux of free fatty acids to the liver, decreased hepatic fatty acid-binding protein expression and decreased lipogenesis. Correlation analysis revealed down-regulation of classical biomarkers of ER stress in their adipose tissue, suggesting that disruption of the IL-1RI-mediated inflammatory response may attenuate cellular stress, which was associated with significant protection from diet-induced insulin resistance, independent of obesity.

Evidence from observational studies, prospective cohort studies and randomized clinical intervention studies indicate that moderate doses of long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) significantly decrease risk of fatal coronary heart disease (CHD). Higher doses and longer duration of intervention may also protect from non-fatal CHD events. The exact mechanisms through which LC n-3 PUFA has an effect on CHD are not well established but may include a decrease in fasting and postprandial triacylglycerol levels, a decrease in arrhythmias, modulation of platelet aggregation and decreased synthesis of pro-inflammatory agents. The mechanistic relation between LC n-3 PUFA and inflammation has attracted great interest, and in vitro studies have revealed that these fatty acids decrease endothelial activation, affect eicosanoid metabolism (including epoxygenation pathways) and induce inflammatory resolution. However, the effects of LC n-3 PUFA on established biomarkers of inflammation and endothelial activation in vivo are not strong. Consequently we need new and more sensitive and systemic biomarkers to reveal the effects of LC n-3 PUFA on localized inflammatory processes.

Blood cells and biofluid proteomics are emerging as a valuable tool to assess effects of interventions on health and disease. This study is aimed to assess the amount and variability of proteins from platelets, peripheral blood mononuclear cells (PBMC), plasma, urine and saliva from ten healthy volunteers for proteomics analysis, and whether protein yield is affected by prolonged fasting. Volunteers provided blood, saliva and morning urine samples once a week for 4 weeks after an overnight fast. Volunteers were fasted for a further 24 h after the fourth sampling before providing their final samples. Each 10 mL whole blood provided 400-1,500 mug protein from platelets, and 100-600 mug from PBMC. 30 muL plasma depleted of albumin and IgG provided 350-650 mug protein. A sample of morning urine provided 0.9-8.6 mg protein/dL, and a sample of saliva provided 70-950 mug protein/mL. None of these yields were influenced by the degree of fasting (overnight or 36 h). In conclusion, in contrast to the yields from plasma, platelets and PBMC, the protein yields of urine and saliva samples were highly variable within and between subjects. Certain disease conditions may cause higher or lower PBMC counts and thus protein yields, or increased urinary protein levels.

Proteomics is emerging as a valuable tool in nutritional research. Proteome analysis from plasma and blood cells can identify thousands of proteins that can potentially provide valuable new biomarkers for health, reveal early indications for disease disposition, assist in dietary responders from nonresponders, and enable the discovery of mechanisms of beneficial food component effects. This review discusses the latest developments in plasma, platelet and peripheral blood mononuclear cell proteomics, specifically in the field of nutritional proteomics, including issues relating to study design, sample preparation and data interpretation.