High linoleic acid, low vegetable, and high oleic acid, high vegetable diets affect platelet activation similarly in healthy women and men

The clinical impact of an extra virgin olive oil enriched mediterranean diet on metabolic syndrome: Lights and shadows of a nutraceutical approach

For years it has been established that the only truly effective treatment of metabolic syndrome (MS) is lifestyle modification to prevent its cardiovascular (e.g., coronary artery disease and atherosclerosis), metabolic (e.g., diabetes mellitus), and hepatic (e.g., steatosis and non-alcoholic steatohepatitis) complications. The focal points of this approach are to increase physical activity and intake of a diet characterized by high quantities of fruits, vegetables, grains, fish, and low-fat dairy products, the so called mediterranean diet (MD); however, the added value of MD is the presence of extra virgin olive oil (EVOO), a healthy food with a high content of monounsaturated fatty acids, especially oleic acid, and variable concentrations (range 50–800 mg/kg) of phenols (oleuropein, ligstroside, and oleocanthal, and their derivatives, phenolic alcohols, such as hydroxytyrosol and tyrosol). Phenolic compounds not only determine EVOO’s main organoleptic qualities (oxidative stability, specific flavor, and taste features) but, theoretically, make it a source of antioxidant, anti-inflammatory, insulin-sensitizing, cardioprotective, antiatherogenic, neuroprotective, immunomodulatory, and anticancer activity. Although many studies have been carried out on EVOO’s clinical effects and attention toward this dietary approach (healthy and palatable food with strong nutraceutical activity) has become increasingly pressing, there are still many dark sides to be clarified, both in terms of actual clinical efficacy and biochemical and molecular activity. Thus, we reviewed the international literature, trying to show the state of the art about EVOO’s clinical properties to treat MS (along with correlated complications) and the future prospective of its nutraceutical use.

Antiplatelet Activity of Cucurbita maxima

Natural extracts constitute an important source in the prevention of noncommunicable diseases, such as cardiovascular diseases. The pumpkin, Cucurbita maxima, is widely consumed in Chile. Pumpkin seeds, despite having crude protein, lipids, and carbohydrates, are regarded as agro-industrial waste. In this work, we correlated the antiplatelet activity of aqueous, ethanolic, and methanolic extracts from pumpkin seeds with their bioactive compounds. In vitro platelet aggregation and activation studies were performed by turbidimetry and flow cytometry, respectively. Results reveal that the extracts inhibited, in a dose-dependent manner, platelet aggregation induced by adenosine diphosphate, thrombin receptor activator peptide 6 (TRAP-6), and collagen. Pumpkin seed extracts inhibited P-selectin secretion and glycoprotein IIb/IIIa activation on TRAP-6-activated platelets. They were found to be rich in fatty acids and a powerful source of plant-based protein, which could be related to the high antiplatelet potential identified in extracts. This research demonstrated that pumpkin seed extracts could be a candidate in the prevention of thrombotic events.

Beneficial effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol in metabolic syndrome: Systematic review and meta-analysis

BACKGROUND AND AIMS

Olive oil and components might have a beneficial effect on Metabolic Syndrome (MetS). The aim of this review and meta-analysis was to assess whether those effects are related to hydroxytyrosol or oleic acid contents, or the combination of them as olive oil, and how powerful is this effect.

METHODS

A systematic literature search was performed in MEDLINE via Pubmed, Web of Science (WOS) core collection, and Virtual Health Library (VHL) via LILACS and IBECS (Spain). MeSH terms used were "obesity", "body weight", "body mass index", "adipose tissue", "lipid metabolism", "LDL", "HDL", "VLDL", "insulin resistance", "glucose", "insulin", "hypertension", "arterial pressure", "olive oil", "oleic acid", and other (non-MeSH) terms: "total antioxidant capacity", "total antioxidant status", "hydroxytyrosol" (PROSPERO ID: CRD42021247614). Results of the included studies were meta-analyzed with the RevMan 5.3 program, assuming a random effects model.

RESULTS

76 articles (67 different trials) were identified. Hydroxytyrosol had no effect on MetS [combined standardized mean differences (SMD) = 0.01 (CI 95%: [-0.23, 0.25], I² = 83%; p = 0.920)]. Oleic acid had no significant beneficial effect on MetS [SMD = 0.03 (CI 95%: [-0.01, 0.07], I² = 0%); p = 0.150], but it improved lipid profile [SMD = 0.06 (CI 95%: [-0.00, 0.12], I² = 0%); p = 0. 050]. Olive oil had no effect on MetS [SMD = -0.01 (CI 95%: [-0.05, 0.03]), I² = 55%; p = 0.550)]. The supplementation with hydroxytyrosol, oleic acid or olive oil showed a beneficial effect on antioxidant capacity related to components of MetS [SMD = 0.31 (CI 95%: [-0.34, 0.95], I² = 81%)]; p = 0.35).

CONCLUSION

Most articles compared olive oil and oleic acid with other strategies specially designed for MetS management. Our findings suggest that olive oil or oleic acid consumption are as good as the other strategies to manage MetS.

Extra virgin olive oil: More than a healthy fat

The beneficial effects of a Mediterranean diet on human health and, in particular, on lowering risk of cardiovascular disease, has been mainly attributed to its high content to extra virgin olive oil (EVOO). While its main fatty acid, oleic acid, is considered important to these effects, EVOO has other biological properties that depend on, or are potentiated by other minor components of this oil. Initially, the mechanisms considered as possible causes of this cardioprotective effect of EVOO were based on the incidence on the so-called traditional risk factors (especially lipids and blood pressure). However, the high relative reduction in the prevalence of cardiovascular morbidity and mortality were not proportional to the limited findings about regulation of those traditional risk factors. In addition to several studies confirming the above effects, current research on beneficial effect of EVOO, and in particular in conjunction with Mediterranean style diets, is being focused on defining its effects on newer cardiovascular risk factors, such as inflammation, oxidative stress, coagulation, platelet aggregation, fibrinolysis, endothelial function or lipids or on the modulation of the conditions which predispose people to cardiovascular events, such as obesity, metabolic syndrome or type 2 diabetes mellitus. In the current review, we will mainly focus on reviewing the current evidence about the effects that EVOO exerts on alternative factors, including postprandial lipemia or coagulation, among others, discussing the underlying mechanism by which it exerts its effect, as well as providing a short review on future directions.

The Fluid Aspect of the Mediterranean Diet in the Prevention and Management of Cardiovascular Disease and Diabetes: The Role of Polyphenol Content in Moderate Consumption of Wine and Olive Oil

A growing interest has emerged in the beneficial effects of plant-based diets for the prevention of cardiovascular disease, diabetes and obesity. The Mediterranean diet, one of the most widely evaluated dietary patterns in scientific literature, includes in its nutrients two fluid foods: olive oil, as the main source of fats, and a low-to-moderate consumption of wine, mainly red, particularly during meals. Current mechanisms underlying the beneficial effects of the Mediterranean diet include a reduction in inflammatory and oxidative stress markers, improvement in lipid profile, insulin sensitivity and endothelial function, as well as antithrombotic properties. Most of these effects are attributable to bioactive ingredients including polyphenols, mono- and poly-unsaturated fatty acids. Polyphenols are a heterogeneous group of phytochemicals containing phenol rings. The principal classes of red wine polyphenols include flavonols (quercetin and myricetin), flavanols (catechin and epicatechin), anthocyanin and stilbenes (resveratrol). Olive oil has at least 30 phenolic compounds. Among them, the main are simple phenols (tyrosol and hydroxytyrosol), secoroids and lignans. The present narrative review focuses on phenols, part of red wine and virgin olive oil, discussing the evidence of their effects on lipids, blood pressure, atheromatous plaque and glucose metabolism.

Collagen-Induced Platelet Aggregates, Diabetes, and Aspirin Therapy Predict Clinical Outcomes in Acute Ischemic Stroke

BACKGROUND

Aggregation of platelets is a trigger for additional development of larger thrombi. This study aimed to identify factors that may affect platelet aggregability and their role in clinical outcomes in acute ischemic stroke.

METHODS

Consecutive acute ischemic stroke patients (n = 352) who were transferred within 24 hours after its onset were enrolled. Peripheral venous blood was sampled to measure platelet aggregability and other parameters.

RESULTS

Mean values of spontaneous small-sized platelet aggregates and collagen- or adenosine diphosphate (ADP)-induced large-sized aggregates were elevated in acute ischemic stroke. In atherothrombotic stroke (n = 178), collagen and ADP-induced large-sized aggregates were positively correlated with HbA1c, respectively. High incidence of the modified Rankin Scales (mRS) 5-6 at discharge was associated with diabetes complication (odds ratio [OR] 8.77, 95% confidence interval [CI] 1.32-57.56). The proportion of patients who were functionally independent (the mRS 0-2) at discharge was lower in the middle tertile of collagen and ADP-induced large-sized aggregates than their low tertile (OR 2.46, 95% CI 1.09-5.58; OR 2.43, 95% CI 1.05-5.59, respectively). Prestroke administration of aspirin recovered the proportion of independence at discharge (OR 0.25, 95% CI 0.06-0.99), and ameliorated incidence of the mRS 5-6. On logistic regression analysis, diabetes, HbA1c, collagen-induced large-sized aggregates, and prestroke administration of aspirin remained independent predictors of clinical outcomes in atherothrombotic stroke. In cardioembolic and lacunar stroke, no relations with clinical outcomes were found.

CONCLUSIONS

High plasma level of HbA1c is involved in enhanced platelet aggregability in acute atherothrombotic stroke patients, and prestroke administration of aspirin may be beneficial to clinical outcomes.

Antiplatelet Aggregation Activity of Walnut Hull Extract via Suppression of Reactive Oxygen Species Generation and Caspase Activation

Walnut hull (wal hull) is an agricultural by-product that is widely used in traditional medicine for alleviating pain and treating skin diseases, however, recently it has gained much attention in modern pharmacology due to its antioxidant properties. The current study was aimed to determine the total phenolic, flavonoid, and tannin content of Persian wal hull extract and evaluate its biological effects on platelet function. Experimental data showed that acetone extract of wal hulls has a high content of polyphenolic compounds and antioxidant properties. The analytical study of crude extract by gas chromatography-mass spectrometry demonstrated different types of high- and low-molecular-weight compounds that are basically and biologically important. Moreover, an in vitro study revealed that wal hull extract at a concentration of 50 μg/mL inhibited thrombin-induced platelet aggregation and protein secretion by 50%, without any cytotoxic effects on platelets. The examined extract suppressed reactive oxygen species generation and also caspase activation in thrombin-stimulated platelets. Identically, N-acetylcysteine inhibited the increase of reactive oxygen species level induced by thrombin in platelets, and supported a link between cellular redox status and caspase activation in activated platelets. Presumably, the antiplatelet activity of wal hull extract is related to its polyphenolic compounds and their antioxidant properties. Therefore, wal hulls can be considered as a candidate for thrombotic disorders.

Olive Oil-Based Lipid Emulsions Do Not Influence Platelet Receptor Expression in Comparison to Medium and Long Chain Triglycerides In vitro

Lipid emulsions influence platelet aggregation and receptor expression. However, the effect on platelet function is not fully explained. Therefore, the aim of this study was to examine the influence of the lipids Lipofundin^®, Lipidem^® and ClinOleic^® on surface expressions of P-selectin, GPIb and GPIIb/IIIa on platelets in vitro. Whole blood was incubated in two different concentrations (0.06 and 0.6 mg/ml) of LCT/MCT, n-3/LCT/MCT and LCT-MUFA for 30 min, followed by activation with TRAP-6 or ADP for flow-cytometric assay. Rates of P-selectin, GPIb and GPIIb/IIIa expression were analyzed. There was a significant increase in GPIIb/IIIa- and P-selectin-expression after incubation with LCT/MCT and n-3/LCT/MCT at the concentration of 0.6 mg/ml, without and after stimulation with TRAP-6 and ADP. GPIb was significantly decreased. Accordingly, LCT-MUFA had no effect on receptor expression of platelets in vitro. We demonstrated that LCT-MUFA did not activate receptor expression of platelets whereas LCT/MCT significantly increased platelet aggregation in vitro. This finding should be noted for parenteral nutrition of intensive care patients and, in the future, might provide further insight into the pathogenic pathways of acute thromboembolic events. However, prospectively designed clinical studies are needed to support our results.

Omega 6 fatty acids for the primary prevention of cardiovascular disease

BACKGROUND

Omega 6 plays a vital role in many physiological functions but there is controversy concerning its effect on cardiovascular disease (CVD) risk. There is conflicting evidence whether increasing or decreasing omega 6 intake results in beneficial effects.

OBJECTIVES

The two primary objectives of this Cochrane review were to determine the effectiveness of:1. Increasing omega 6 (Linoleic acid (LA), Gamma-linolenic acid (GLA), Dihomo-gamma-linolenic acid (DGLA), Arachidonic acid (AA), or any combination) intake in place of saturated or monounsaturated fats or carbohydrates for the primary prevention of CVD.2. Decreasing omega 6 (LA, GLA, DGLA, AA, or any combination) intake in place of carbohydrates or protein (or both) for the primary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases up to 23 September 2014: the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library (Issue 8 of 12, 2014); MEDLINE (Ovid) (1946 to September week 2, 2014); EMBASE Classic and EMBASE (Ovid) (1947 to September 2014); Web of Science Core Collection (Thomson Reuters) (1990 to September 2014); Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment Database, and Health Economics Evaluations Database on the Cochrane Library (Issue 3 of 4, 2014). We searched trial registers and reference lists of reviews for further studies. We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of interventions stating an intention to increase or decrease omega 6 fatty acids, lasting at least six months, and including healthy adults or adults at high risk of CVD. The comparison group was given no advice, no supplementation, a placebo, a control diet, or continued with their usual diet. The outcomes of interest were CVD clinical events (all-cause mortality, cardiovascular mortality, non-fatal end points) and CVD risk factors (changes in blood pressure, changes in blood lipids, occurrence of type 2 diabetes). We excluded trials involving exercise or multifactorial interventions to avoid confounding.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted the data, and assessed the risk of bias in the included trials.

MAIN RESULTS

We included four RCTs (five papers) that randomised 660 participants. No ongoing trials were identified. All included trials had at least one domain with an unclear risk of bias. There were no RCTs of omega 6 intake reporting CVD clinical events. Three trials investigated the effect of increased omega 6 intake on lipid levels (total cholesterol, low density lipoprotein (LDL-cholesterol), and high density lipoprotein (HDL-cholesterol)), two trials reported triglycerides, and two trials reported blood pressure (diastolic and systolic blood pressure). Two trials, one with two relevant intervention arms, investigated the effect of decreased omega 6 intake on blood pressure parameters and lipid levels (total cholesterol, LDL-cholesterol, and HDL-cholesterol) and one trial reported triglycerides. Our analyses found no statistically significant effects of either increased or decreased omega 6 intake on CVD risk factors.Two studies were supported by funding from the UK Food Standards Agency and Medical Research Council. One study was supported by Lipid Nutrition, a commercial company in the Netherlands and the Dutch Ministry of Economic Affairs. The final study was supported by grants from the Finnish Food Research Foundation, Finnish Heart Research Foundation, Aarne and Aili Turnen Foundation, and the Research Council for Health, Academy of Finland.

AUTHORS' CONCLUSIONS

We found no studies examining the effects of either increased or decreased omega 6 on our primary outcome CVD clinical endpoints and insufficient evidence to show an effect of increased or decreased omega 6 intake on CVD risk factors such as blood lipids and blood pressure. Very few trials were identified with a relatively small number of participants randomised. There is a need for larger well conducted RCTs assessing cardiovascular events as well as cardiovascular risk factors.

Prediction of fruit and vegetable intake from biomarkers using individual participant data of diet-controlled intervention studies

Fruit and vegetable consumption produces changes in several biomarkers in blood. The present study aimed to examine the dose–response curve between fruit and vegetable consumption and carotenoid (α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin), folate and vitamin C concentrations. Furthermore, a prediction model of fruit and vegetable intake based on these biomarkers and subject characteristics (i.e. age, sex, BMI and smoking status) was established. Data from twelve diet-controlled intervention studies were obtained to develop a prediction model for fruit and vegetable intake (including and excluding fruit and vegetable juices). The study population in the present individual participant data meta-analysis consisted of 526 men and women. Carotenoid, folate and vitamin C concentrations showed a positive relationship with fruit and vegetable intake. Measures of performance for the prediction model were calculated using cross-validation. For the prediction model of fruit, vegetable and juice intake, the root mean squared error (RMSE) was 258·0 g, the correlation between observed and predicted intake was 0·78 and the mean difference between observed and predicted intake was − 1·7 g (limits of agreement: − 466·3, 462·8 g). For the prediction of fruit and vegetable intake (excluding juices), the RMSE was 201·1 g, the correlation was 0·65 and the mean bias was 2·4 g (limits of agreement: − 368·2, 373·0 g). The prediction models which include the biomarkers and subject characteristics may be used to estimate average intake at the group level and to investigate the ranking of individuals with regard to their intake of fruit and vegetables when validating questionnaires that measure intake.

Dietary manipulation of platelet function

Activated platelets contribute to plaque formation within blood vessels in the early and late stages of atherogenesis, and therefore they have been proposed as risk factor for cardiovascular disease. Anti-platelet drugs, such as aspirin, are now the most prescribed pharmacological treatment in Europe. Certain dietary bioactives also beneficially affect platelet function, and with less side effects, albeit that effects are generally more subtle. Therefore, consumption of dietary bioactives could play a role in the prevention of atherothrombotic vascular disease. Here we review the efficacy of dietary treatment strategies, especially those involving certain dietary fatty acids and polyphenols, to modulate platelet function in healthy subjects or in patients with cardiovascular disease. Variation in study populations, small study sizes and lack of comparability between methods to assess platelet function currently limit robust evidence on the efficacy of dietary bioactives in healthy subjects or specific patient groups. Also, limited knowledge of the metabolism of dietary bioactives, and therefore of the bioavailability of bioactive ingredients, restricts our ability to identify the most effective dietary regimes to improve platelet function. Implementation of uniform point-of-care tests to assess platelet function, and enhanced knowledge of the efficacy by which specific dietary compounds and their metabolites affect platelet function, may enable the identification of functional anti-platelet ingredients that are eligible for a health claim, or combined treatment strategies, including both pharmacological anti-platelet treatment as well as dietary intervention, to tackle atherothrombotic vascular disease.

Olive oil and the haemostatic system

Interest in the Mediterranean diet (MD) has grown worldwide due to its link with greater longevity and lower cardiovascular disease rate, cancer and age cognitive decline. Despite the high complexity of its nutrients composition, olive oil emerges as its principal food, since it provides the higher percent of energy and a lot of bioactive compounds. In this review we will discuss the benefits of diets enriched in virgin olive oil, whose effects are probably due not only to its oleic acid content but also to its other potentially health-promoting components. Traditionally, the benefits of MD were linked to its effect on lipoprotein metabolism but today we realise that there exists a whole sheaf of other benefits, including the components of haemostasis: platelet function, thrombogenesis and fibrinolysis. A diet enriched in virgin olive oil can reduce the sensitivity of platelets to aggregation, decreasing von Willebrand and tromboxane B2 plasma levels. Moreover a particular interest has arisen about its capacity to decrease fasting Factor VII plasma levels and to avoid or modulate its postprandial activation. Also Tissue Factor expression in mononuclear cells could be reduced with the chronic intake of virgin olive oil and finally, studies performed in different experimental situation have shown that it could also increase fibrinolytic activity, reducing plasma concentration of Plasma Activator Inhibitor type-1.

Mechanism of oleic acid-induced gap junctional disassembly in rat cardiomyocytes

This study investigated the mechanism of oleic acid (OA) on gap junctions and identified the protein kinase C (PKC) isoforms involved in OA-mediated gap junction disassembly in cardiomyocytes. Control cardiomyocytes showed continuous staining of the plasma membrane at cell-cell contact areas using antibodies reacting with connexin 43 (Cx43). The spontaneous contraction rate of cultured cardiomyocytes was reduced in a time-dependent manner by OA. In addition, Cx43 expression at cell-cell junction decreased, suggesting the disassembly of gap junction. Staining for PKC and PKCalpha, which were shown to colocalize with Cx43, also decreased with increased duration of OA treatment. The effects of OA on these distributional changes at cell junctions were reversed by 24 h incubation in fresh culture medium devoid of OA. Immunoprecipitation assays confirmed the biochemical binding between Cx43 and PKC/PKCalpha, and this protein interaction was not affected by OA. This may provide the basis for simultaneous detachment of Cx and PKC/PKCalpha from the cell-cell junction to the cytosol upon OA stimulation. Western blot analysis showed that OA-induced Cx43 Ser368 phosphorylation, and that this effect could be blocked by cotreatment with the general PKC inhibitor, calphostin C, the PKC inhibitor, eV1-2, or the Src kinase inhibitor, PP1, but not by the PKCalpha inhibitor, Gö6976. eV1-2 also prevented the OA-induced disassembly of gap junctions. Taken together, these data suggest that OA-induced Cx43 Ser368 phosphorylation is mediated by activation of PKC and Src kinase and might be responsible for OA-induced gap junctional disassembly.

Platelet function tests using platelet aggregometry: need for repetition of the test for diagnosis of defective platelet function

Four hundred and ninety seven patients were referred to our center for platelet aggregation studies because of spontaneous mucocutaneous bleeds. All these patients had normal complete blood count, platelet count and peripheral smears except in ten patients of Bernard Soulier Syndrome where platelet count was marginally reduced in the presence of giant platelets. Two hundred and eighty patients were found to have normal platelet aggregation to ADP, collagen, ristocetin and arachidonic acid. Out of the remaining 217 patients, 62 patients were diagnosed to have Glanzmanns thrombasthenia, 10 Bernard Soulier Syndrome, 6 storage pool deficiencies, 7 cyclooxygenase deficiencies and 72 von Willebrand disease. In all the patients with GT and BSS, diagnosis was confirmed with flow cytometry using multiple monoclonal antibodies to GPIIb-IIIa and GPIb-IX. There were sixty patients where initial platelet aggregation studies showed reduced (<30%) aggregation to either ADP, collagen, ristocetin or arachidonic acid in its various combination, however in 12 such patients (20%) the platelet aggregation studies were normal on repetition. All our platelet aggregation studies were done only after assuring that the patient is not taking any medicine for at least 7-10 days which may affect the platelet function tests. The present study shows that single atypically abnormal platelet aggregation studies should always be repeated. Finally in 48/217 patients (22%) some aggregation abnormality to one or more of the agonists persisted, although we could not categorize these patients into any clear-cut platelet disorder. None of these 48 patients platelet associated immunoglobulin was increased by flow cytometry. It is possible that large number of patients from that disorder will finally prove to be some form of platelet secretory defect. In north India similar group of defect in a large number of patients have been reported as isolated PF3 abnormality or thrombasthenic thrombopathy.