Lipoproteínas, plaquetas y aterotrombosis

Predictive modeling of lower extreme deep vein thrombosis following radical gastrectomy for gastric cancer: based on multiple machine learning methods

Postoperative venous thromboembolic events (VTEs), such as lower extremity deep vein thrombosis (DVT), are major risk factors for gastric cancer (GC) patients following radical gastrectomy. Accurately predicting and managing these risks is crucial for optimal patient care. This retrospective case‒control study involved 693 GC patients from our hospital who underwent radical gastrectomy. We collected plentiful and comprehensive clinical indicators including a total of 49 baseline, preoperative, surgical and pathological clinical data. Using univariate logistic regression, we identified potential risk factors, followed by feature selection through the Boruta algorithm. We then constructed the final predictive model using multivariate logistic regression and evaluated it using receiver operating characteristic (ROC) curve analysis, calibration plots, decision curve analysis, and other methods. Additionally, we applied various machine learning techniques, including decision trees and random forests, to assess our model's predictive strength. This retrospective case‒control study involved 693 GC patients from our hospital who underwent radical gastrectomy. We collected plentiful and comprehensive clinical indicators including a total of 49 baseline, preoperative, surgical and pathological clinical data. Using univariate logistic regression, we identified potential risk factors, followed by feature selection through the Boruta algorithm. We then constructed the final predictive model using multivariate logistic regression and evaluated it using receiver operating characteristic (ROC) curve analysis, calibration plots, decision curve analysis, and other methods. Additionally, we applied various machine learning techniques, including decision trees and random forests, to assess our model's predictive strength. Univariate logistic analysis revealed 14 risk factors associated with postoperative lower limb DVT. Based on the Boruta algorithm, six significant clinical factors were selected, namely, age, D-dimer (D-D) level, low-density lipoprotein, CA125, and calcium and chloride ion levels. A nomogram was developed using the outcomes from the multivariate logistic regression analysis. The predictive model showed high accuracy, with an area under the curve of 0.936 in the training set and 0.875 in the validation set. Various machine learning algorithms confirmed its strong predictive capacity. MR analysis revealed meaningful causal relationships between key clinical factors and DVT risk. Based on various machine learning methods, we developed an effective predictive diagnostic model for postoperative lower extremity DVT in GC patients. This model demonstrated excellent predictive value in both the training and validation sets. This novel model is a valuable tool for clinicians to use in identifying and managing thrombotic risks in this patient population.

Endothelial Dysfunction in Obesity and Therapeutic Targets

Parallel to the increasing prevalence of obesity in the world, the mortality from cardiovascular disease has also increased. Low-grade chronic inflammation in obesity disrupts vascular homeostasis, and the dysregulation of adipocyte-derived endocrine and paracrine effects contributes to endothelial dysfunction. Besides the adipose tissue inflammation, decreased nitric oxide (NO)-bioavailability, insulin resistance (IR), and oxidized low-density lipoproteins (oxLDLs) are the main factors contributing to endothelial dysfunction in obesity and the development of cardiorenal metabolic syndrome. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in the profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Higher stiffness parameter β, increased oxidative stress, upregulation of pro-inflammatory cytokines, and nicotinamide adenine dinucleotide phosphate (NADP) oxidase in PVAT turn the macrophages into pro-atherogenic phenotypes by oxLDL-induced adipocyte-derived exosome-macrophage crosstalk and contribute to the endothelial dysfunction. In clinical practice, carotid ultrasound, higher leptin levels correlate with irisin over-secretion by human visceral and subcutaneous adipose tissues, and remnant cholesterol (RC) levels predict atherosclerotic disease in obesity. As a novel therapeutic strategy for cardiovascular protection, liraglutide improves vascular dysfunction by modulating a cyclic adenosine monophosphate (cAMP)-independent protein kinase A (PKA)-AMP-activated protein kinase (AMPK) pathway in PVAT in obese individuals. Because the renin-angiotensin-aldosterone system (RAAS) activity, hyperinsulinemia, and the resultant IR play key roles in the progression of cardiovascular disease in obesity, RAAS-targeted therapies contribute to improving endothelial dysfunction. By contrast, arginase reciprocally inhibits NO formation and promotes oxidative stress. Thus, targeting arginase activity as a key mediator in endothelial dysfunction has therapeutic potential in obesity-related vascular comorbidities. Obesity-related endothelial dysfunction plays a pivotal role in the progression of type 2 diabetes (T2D). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone (thiazolidinedione), is a popular drug for treating diabetes; however, it leads to increased cardiovascular risk. Selective sodium-glucose co-transporter-2 (SGLT-2) inhibitor empagliflozin (EMPA) significantly improves endothelial dysfunction and mortality occurring through redox-dependent mechanisms. Although endothelial dysfunction and oxidative stress are alleviated by either metformin or EMPA, currently used drugs to treat obesity-related diabetes neither possess the same anti-inflammatory potential nor simultaneously target endothelial cell dysfunction and obesity equally. While therapeutic interventions with glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide or bariatric surgery reverse regenerative cell exhaustion, support vascular repair mechanisms, and improve cardiometabolic risk in individuals with T2D and obesity, the GLP-1 analog exendin-4 attenuates endothelial endoplasmic reticulum stress.

New atherogenic index for the prediction of carotid atherosclerosis based on the non-ultrasensitive c-reactive protein/HDL ratio

INTRODUCTION

Current guidelines recommend cardiovascular risk assessment as a preventive measure for cardiovascular diseases, whose fundamental etiology is arteriosclerosis. One of the tools used to estimate risk in clinical practice are atherogenic indices (AI), ratios between lipid fractions with well-established reference ranges. Despite its widespread use, there is still limited information on its clinical utility. In recent years, some research has reinforced the role of inflammation in the etiology and chronicity of the atherosclerotic process. The inclusion of inflammatory parameters in the AI calculation could improve its diagnostic performance in the detection of arteriosclerosis. We sought to evaluate a new AI as a ratio between C-reactive protein (CRP) values and high-density lipoprotein cholesterol (HDL) values.

METHODS

A total of 282 asymptomatic patients with no history of cardiovascular disease were included in the study. Laboratory tests with lipid profile and CRP, and carotid ultrasound to assess the presence of atheromatosis were performed in all of them. The new AI is established as the ratio between non-ultrasensitive CRP value in mg/dL (multiplied by 100) and HDL value in mg/dL. It was compared with the Castelli I and II indices, and the plasma atherogenic index. The optimal cut-off point of the new AI was value=1 as determined by ROC curve, with an area under the curve of 0.678 (95% CI 0.60-0.75; p<0.001).

RESULTS

Mean age of patients was 60.4±14.5 years. A total of 118 patients (41.8% of total) had carotid arteriosclerosis. When evaluating the diagnostic performance of different AIs, we found that CRP·100/HDL ratio showed the highest values of sensitivity and positive predictive value (0.73 and 0.68, respectively) compared to the Castelli I and II indices, and the plasma atherogenic index. It was also the only predictor of carotid atheromatosis both when considering its values quantitatively (with OR 1.4 [95% CI 1.1-1.7]; p=0.005), and qualitatively (with OR 2.9 [95% CI 1.5-5.5]; p<0.001) in patients with a CRP·100/HDL ratio>1.

CONCLUSIONS

The new PCR·100/HDL index showed the best diagnostic performance in the detection of carotid atheromatosis compared to other classic AIs in this Spanish population of asymptomatic patients.

Time-resolved simulation of blood flow through left anterior descending coronary artery: effect of varying extent of stenosis on hemodynamics

BACKGROUND AND OBJECTIVES

Real-time blood flow variation is crucial for understanding the dynamic development of coronary atherosclerosis. The main objective of this study is to investigate the effect of varying extent of stenosis on the hemodynamic features in left anterior descending coronary artery.

METHODS

Various Computational fluid dynamics (CFD) models were constructed with patient-specific CT image data, using actual fractional flow reserve (FFR) as boundary conditions to provide a real-time quantitative description of hemodynamic properties. The hemodynamic parameters, such as the local and instantaneous wall shear stress (WSS), oscillating shear index (OSI) and relative residence time (RRT), blood flow velocity and pressure drop during various phases of cardiac cycle were provided in detail.

RESULTS

There was no evident variation in hemodynamic parameters in the cases of less than 50% stenosis while there were abrupt and dramatic changes in hemodynamics when the stenosis aggravated from 60 to 70%. Furthermore, when the stenosis was beyond 70%, there existed substantial pressure difference, WSS, and blood flow velocity in the center of the stenosis. Although OSI and RRT increased along with the aggravation of stenosis, they appeared with obvious abnormalities across all cases, even in mild stenosis.

CONCLUSION

The simulation could present a dynamic and comprehensive profile of how hemodynamic parameters vary in accordance with divergent severities of stenosis, which could serve as an effective reference for the clinicians to have a deeper insight into the pathological mechanism of coronary atherosclerosis and stenosis.

Bidirectional role of reactive oxygen species during inflammasome activation in acrolein-induced human EAhy926 cells pyroptosis

Acrolein, a known toxin in tobacco smoke, has been demonstrated to be associated with inflammatory cardiovascular diseases, such as atherosclerosis. However, the definite mechanism of acrolein-induced inflammation remains unclear. Here, we report that acrolein induces reactive oxygen species (ROS) production in EAhy926 cells. Additionally, acrolein induces EAhy926 cells' inflammatory response and pyroptosis by activating NOD-like receptor protein 3 (NLRP3) inflammasome. Also, acrolein-induced cytotoxicity could be attenuated by N-acetyl-L-cysteine (NAC). Furthermore, acrolein upregulates the level of autophagy which can be reversed by NAC. Notably, the present study also indicates that autophagy inhibited by inhibitor 3-methyladenine (3MA) and siAtg7 exacerbate acrolein-induced NLRP3 inflammasome activation and pyroptosis. In summary, acrolein induced cytotoxicity by ROS-mediated NLRP3 inflammasome activation, and ROS upregulates the level of autophagy to inhibit the NLRP3 inflammasome excessive activation, indicating the bidirectional role of ROS in acrolein-induced cellular inflammation. Our results may provide novel mechanistic insights into acrolein-induced cardiovascular toxicity.

LDL-Cholesterol and Platelets: Insights into Their Interactions in Atherosclerosis

Atherosclerosis and its complications, including acute coronary syndromes, are the major cause of death worldwide. The two most important pathophysiological mechanisms underlying atherosclerosis include increased platelet activation and increased low-density lipoproteins (LDL) concentration. In contrast to LDL, oxidized (ox)-LDL have direct pro-thrombotic properties by functional interactions with platelets, leading to platelet activation and favoring thrombus formation. In this review, we summarize the currently available evidence on the interactions between LDL-cholesterol and platelets, which are based on (i) the presence of ox-LDL-binding sites on platelets, (ii) generation of ox-LDL by platelets and (iii) the role of activated platelets and ox-LDL in atherosclerosis. In addition, we elaborate on the clinical implications of these interactions, including development of the new therapeutic possibilities. The ability to understand and modulate mechanisms governing interactions between LDL-cholesterol and platelets may offer new treatment strategies for atherosclerosis prevention.

Clopidogrel or prasugrel reduces mortality and lessens cardiovascular damage from acute myocardial infarction in hypercholesterolemic male rats

AIMS

Hypercholesterolemia is a hazard for increasing susceptibility of the heart to myocardial infarction (MI) by inducing platelet hyperaggregability. Clopidogrel and prasugrel have documented cardioprotective effects in clinical studies. Herein, we investigated whether clopidogrel and prasugrel could protect against isoproterenol-induced acute MI (A-MI) under hypercholesterolemic conditions in rats.

MAIN METHODS

Dietary hypercholesterolemic rats were subjected to acute doses of isoproterenol. Serum lipids, inflammatory markers, aortic endothelin1 and endothelial nitric oxide synthase (eNOS) mRNAs expression and immunexpression of BCL2 were determined.

KEY FINDINGS

Hypercholesterolemic rats showed infiltration of inflammatory cells and reduction in aortic wall thickness, deposition of fibrous tissue between cardiac muscle fibers. Protective doses of prasugrel or clopidogrel for 28 days before A-MI increased survival, amended the ECG parameters -including ST segment elevation- and improved the histopathological picture in hypercholesterolemic rats. This was coupled with reductions in platelet aggregation, creatine kinase-MB activity, endothelin 1, systemic inflammation and cardiac lipid peroxidation and increment in aortic eNOS expression. Clopidogrel and prasugrel groups showed enhanced BCL2 expression in cardiac fibers and aortic wall.

SIGNIFICANCE

Prasugrel and clopidogrel protected against A-MI via anti-aggregatory and anti-inflammatory effects. These results add to the value of these drugs in correcting cardiovascular dysfunction in patients vulnerable to A-MI after confirmation by appropriate human studies.

Soyasaponins A1 and A2 exert anti-atherosclerotic functionalities by decreasing hypercholesterolemia and inflammation in high fat diet (HFD)-fed ApoE-/- mice

Atherosclerosis is a chronic inflammatory disease causing coronary heart attacks and strokes. Soyasaponins (SS), the phytochemicals naturally existing in soybeans and their products, have been shown to reduce hypercholesterolemia and inflammation, which are intimately related to the genesis and development of atherosclerosis. However, the anti-atherosclerotic functionality of soyasaponins remains unknown. The aim of this study was to investigate the effects of the supplementation of two types of soyasaponin monomers (A1 and A2) on atherosclerotic plaque formation, serum lipid profiles, and inflammation in ApoE gene knockout (ApoE-/-) mice. Sixty 5-week-old ApoE-/- male mice were fed with a high-fat diet (HFD) and intervened by SSA1 and SSA2 (10 and 20 μmol per kg BW, respectively) or simvastatin (10 μmol per kg BW) for 24 weeks. The atherosclerotic lesions in the aorta, aortic root, and innominate artery, lipid profile and inflammatory markers in serum, and TLR4/MyD88/NF-κB signaling in arterial tissues were determined. SSA1 and SSA2 decreased the plaque ratio in the aortic root and innominate artery but not in the entire aorta. In serum, SSA1 reduced TG, TC, and LDL-C but increased HDL-C; SSA2 decreased TC, TG, and LDL-C but did not affect HDL-C. Meanwhile, SSA1 increased TG, SSA2 increased TC, and both of them increased bile acids in the feces. SSA1 and SSA2 lowered TNF-α, MCP-1, and hs-crp in serum. Furthermore, SSA1 and SSA2 reduced the TLR4 and MyD88 expressions in the aorta and innominate artery and inhibited NF-κB p65 and IκBα phosphorylation in the aorta. These results suggest that SSA1 and SSA2 exert anti-atherosclerotic functionalities by decreasing hypercholesterolemia and inflammation in HFD-fed ApoE-/- mice.

Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation

Atherosclerosis is a chronic vascular inflammatory disease associated to oxidative stress and endothelial dysfunction. Oxidation of low-density lipoprotein (LDL) cholesterol is one of the key factors for the development of atherosclerosis. Nonoxidized LDL have a low affinity for macrophages, so they are not themselves a risk factor. However, lowering LDL levels is a common clinical practice to reduce oxidation and the risk of major events in patients with cardiovascular diseases (CVD). Atherosclerosis starts with dysfunctional changes in the endothelium induced by disturbed shear stress which can lead to endothelial and platelet activation, adhesion of monocytes on the activated endothelium, and differentiation into proinflammatory macrophages, which increase the uptake of oxidized LDL (oxLDL) and turn into foam cells, exacerbating the inflammatory signalling. The atherosclerotic process is accelerated by a myriad of factors, such as the release of inflammatory chemokines and cytokines, the generation of reactive oxygen species (ROS), growth factors, and the proliferation of vascular smooth muscle cells. Inflammation and immunity are key factors for the development and complications of atherosclerosis, and therefore, the whole atherosclerotic process is a target for diagnosis and treatment. In this review, we focus on early stages of the disease and we address both biomarkers and therapeutic approaches currently available and under research.

Vorapaxar stabilizes permeability of the endothelial barrier under cholesterol stimulation via the AKT/JNK and NF‑κB signaling pathways

Atherosclerosis (AS) is an inflammatory disease that occurs in the arterial wall and is characterized by progressive lipid accumulation within the intima of large arteries, leading to the dysfunction of endothelial cells and further destruction of the endothelial barrier and vascular tone. Arterial intima injury accelerates the adhesion and activation of platelets at the injury site. The activation of platelets results in the secretion of growth factors, leading to the migration and proliferation of vascular smooth muscle cells (VSMCs), promoting the formation of plaque, resulting in the formation of thrombus. The present study found that vorapaxar could alleviate the inflammatory response induced by a high concentration of cholesterol stimulation and increase the release of nitric oxide (NO) via the protein kinase B (AKT) signaling pathway and regulation of the intracellular concentration of Ca2+ ([Ca2+]i). We also found that vorapaxar could reduce the damage of DNA caused by cholesterol stimulation and regulate the cell cycle via the AKT/JNK signaling pathway and its downstream molecules glycogen synthase kinase 3β (GSK‑3β) and connexin 43, maintaining the integrity of the endothelial barrier and proliferation of endothelial cells, serving a protective role in endothelial cells.

Flavonoids and Platelet-Derived Thrombotic Disorders

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Thrombotic disorders are characterized by an increase in the probability of the formation of unnecessary thrombi that might be due to the activation of the coagulation cascade or the circulating platelets. Platelets or thrombocytes play an essential role in hemostasis but abnormal platelet function leads to the development of a number of cardiovascular complications, including thrombotic disorders. Under pathological conditions, platelets are associated with the development of different thrombotic disorders, including atherosclerosis, arterial thrombosis and stroke, deep venous thrombosis and pulmonary embolism; therefore, platelets are the target of a number of anti-thrombotic strategies. Flavonoids, a large group of polyphenols ubiquitously expressed in fruits and vegetables that have attracted considerable attention because of their benefits in human health, including the reduction of the risk of cardiovascular disease. Flavonoids have been reported to reduce platelet activity by attenuating agonist-induced GPIIb/IIIa receptor activation, mobilization of intracellular free Ca2+, granule exocytosis, as well as activation of different signaling molecules such as mitogen- activated protein kinases or phospholipases. This review summarizes the current studies concerning the modulation of platelet activation by flavonoids, giving especial attention to those events associated to thrombotic disorders.

Conditional GWAS revealing genetic impacts of lifestyle behaviors on low-density lipoprotein (LDL)

BACKGROUND

Accumulation of LDL cholesterol (LDL-c) within artery walls is strongly associated with the initiation and progression of atherosclerosis development. This complex trait is affected by multifactor involving polygenes, environments, and their interactions. Uncovering genetic architecture of LDL may help to increase the understanding of the genetic mechanism of cardiovascular diseases.

METHODS

We used a genetic model to analyze genetic effects including additive, dominance, epistasis, and ethnic interactions for data from the Multi-Ethnic Study of Atherosclerosis (MESA). Three lifestyle behaviors (reading, intentional exercising, smoking) were used as cofactor in conditional models.

RESULTS

We identified 156 genetic effects of 10 quantitative trait SNPs (QTSs) in base model and three conditional models. The total estimated heritability of these genetic effects was approximately 72.88% in the base model. Five genes (CELSR2, MARK2, ADAMTS12, PFDN4, and MAGI2) have biological functions related to LDL.

CONCLUSIONS

Compared with the based model LDL, the results in three conditional models revealed that intentional exercising and smoking could have impacts for causing and suppressing some of genetic effects and influence the levels of LDL. Furthermore, these two lifestyles could have different genetic effects for each ethnic group on a specific QTS. As most of the heritability in based model LDL and conditional model LDL|Smk was contributed from epistasis effects, our result indicated that epistasis effects played important roles in determining LDL levels. Our study provided useful insight into the biological mechanisms underlying regulation of LDL and might help in the discovery of novel therapeutic targets for cardiovascular disease.

The effects of pigment epithelium-derived factor on atherosclerosis: putative mechanisms of the process

Cardiovascular disease (CVD) is a leading cause of death worldwide. Atherosclerosis is believed to be the major cause of CVD, characterized by atherosclerotic lesion formation and plaque disruption. Although remarkable advances in understanding the mechanisms of atherosclerosis have been made, the application of these theories is still limited in the prevention and treatment of atherosclerosis. Therefore, novel and effective strategies to treat high-risk patients with atherosclerosis require further development. Pigment epithelium-derived factor (PEDF), a glycoprotein with anti-inflammatory, anti-oxidant, anti-angiogenic, anti-thrombotic and anti-tumorigenic properties, is of considerable interest in the prevention of atherosclerosis. Accumulating research has suggested that PEDF exerts beneficial effects on atherosclerotic lesions and CVD patients. Our group, along with colleagues, has demonstrated that PEDF may be associated with acute coronary syndrome (ACS), and that the polymorphisms of rs8075977 of PEDF are correlated with coronary artery disease (CAD). Moreover, we have explored the anti-atherosclerosis mechanisms of PEDF, showing that oxidized-low density lipoprotein (ox-LDL) reduced PEDF concentrations through the upregulation of reactive oxygen species (ROS), and that D-4F can protect endothelial cells against ox-LDL-induced injury by preventing the downregulation of PEDF. Additionally, PEDF might alleviate endothelial injury by inhibiting the Wnt/β-catenin pathway. These data suggest that PEDF may be a novel therapeutic target for the treatment of atherosclerosis. In this review, we will summarize the role of PEDF in the development of atherosclerosis, focusing on endothelial dysfunction, inflammation, oxidative stress, angiogenesis and cell proliferation. We will also discuss its promising therapeutic implications for atherosclerosis.

Effects of fermented Sorghum bicolor L. Moench extract on inflammation and thickness in a vascular cell and atherosclerotic mice model

Atherosclerosis is a major cause of coronary heart disease. As a result of the development of atherosclerotic lesions, the walls of blood vessels become thicker and inhibit blood circulation. Atherosclerosis is caused by a high-fat diet and vascular injury. Chronic arterial inflammation plays an important role in the pathogenesis of atherosclerosis. In particular, secretion of the pro-atherogenic cytokine tumor necrosis factor-α induces expression of endothelial adhesion molecules including P-selectin, vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1), which mediate attachment of circulating monocytes and lymphocytes. In this study, we examined the anti-atherosclerotic effect of sorghum, which is known to have anti-oxidant and anti-inflammatory activity. A 50% ethanol extract of Sorghum bicolor L. Moench fermented with Aspergillus oryzae NK (fSBE) was used for experiments. In vitro expression of endothelial adhesion molecules VCAM-1 and ICAM-1 and pro-inflammatory factor cyclooxygenase-2 was significantly decreased and that of the anti-atherogenic factor heme oxygenase-1 significantly increased by fSBE (P < 0.05). At the in vivo level, we examined fat droplets of liver tissue, and aortic thickness via histological analysis, and determined the blood lipid profile through chemical analysis. fSBE at a dose of 200 mg/kg significantly improved blood and vascular health (P < 0.05). Taken together, these results demonstrate that fSBE has potential as a therapeutic anti-atherosclerotic agent.

Native High-Density Lipoprotein and Melatonin Improve Platelet Response Induced by Glycated Lipoproteins

Activated platelets and glycated lipoproteins are responsible for atherothrombosis in diabetics. Melatonin and native high-density lipoproteins are crucial in the preservation of pro/oxidant-antioxidant balance. The aim of the present study was to investigate the in vitro effects of native high-density lipoproteins and melatonin on altering the platelet response induced by glycated lipoproteins. Low-density lipoproteins and high-density lipoproteins were purified from plasma by ultracentrifugation and were glycated with glucose for three weeks. After incubation with or without melatonin/or native highdensity lipoproteins, low-density lipoproteins, glycated low-density lipoproteins/glycated high-density lipoproteins were added to ADP-induced platelets. Oxidative parameters, caspase-3/9 and nitric oxide levels were measured spectrophotometrically; CD62-P/ annexin-V expression was determined by flow cytometry. In glycated low-density lipoprotein/glycated high-density lipoprotein-treated groups, platelet malondialdehyde/ protein carbonyl, P-selectin, annexin-V, caspase-3/9 levels were increased (ranging from P < 0.001 to P < 0.01); glutathione and nitric oxide levels were reduced (ranging from P < 0.001 to P < 0.01). In glycated low-density lipoprotein/glycated high-density lipoprotein-treated groups, melatonin treatment reduced malondialdehyde, protein carbonyl, CD62-P, annexin-V and caspase-3/9 (P < 0.001, P < 0.01) levels and elevated nitric oxide (only glycated low-density lipoproteins). In glycated low-density lipoprotein/glycated high-density lipoprotein-treated groups, native high-density lipoprotein treatment reduced malondialdehyde, protein carbonyl, annexin-V, caspase-3/9 levels (P < 0.001, P < 0.01) and increased glutathione; nitric oxide levels (only with gly-HDL). Both melatonin and high-density lipoproteins should be regarded as novel promising mechanism-based potential therapeutic targets to prevent atherothrombosis in diabetics.

Cholesterol-lowering effect of astringent persimmon fruits (Diospyros kaki Thunb.) extracts

This study aimed to investigate the effects of ethanol extract of astringent persimmon on antioxidant activity, cholesterol, 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase activity, and mRNA expression of cholesterol metabolism-related genes in human hepatoma cell line (HepG2 cells). In the results, DPPH and ABTS radical scavenging activity showed that the different types cultivars of astringent persimmon was similar to Vitamin C as positive control. However, there are not significant differences among samples. In addition, our results showed that cholesterol amounts and HMG-CoA reductase activity were inhibited by astringent persimmon in HepG2 cells. Further, treatment with astringent persimmon upregulated the expression of LDL receptor and SREBP-2, and also increased the level of HDL-associated ABCA1. Taken together, our results indicate that astringent persimmon regulate cholesterol accumulation by inhibiting the oxidative stress and controlling the levels of LDL & HDLassociated gene.

Endothelial Dysfunction in Obesity

Chronic inflammatory state in obesity causes dysregulation of the endocrine and paracrine actions of adipocyte-derived factors, which disrupt vascular homeostasis and contribute to endothelial vasodilator dysfunction and subsequent hypertension. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Adipose tissue inflammation, nitric oxide (NO)-bioavailability, insulin resistance and oxidized low-density lipoprotein (oxLDL) are main participating factors in endothelial dysfunction of obesity. In this chapter, disruption of inter-endothelial junctions between endothelial cells, significant increase in the production of reactive oxygen species (ROS), inflammation mediators, which are originated from inflamed endothelial cells, the balance between NO synthesis and ROS , insulin signaling and NO production, and decrease in L-arginine/endogenous asymmetric dimethyl-L-arginine (ADMA) ratio are discussed in connection with endothelial dysfunction in obesity.

Dyslipidemia Part 1--Review of Lipid Metabolism and Vascular Cell Physiology

Dyslipidemia, more specifically, high-serum low-density lipoproteins and low-serum high-density lipoproteins, are known risk factors for cardiovascular disease. The current clinical treatment of dyslipidemia represents the outcome of a large body of fundamental basic science research on lipids, lipid metabolism, and the effects of different lipids on cellular components of the artery, inflammatory cells, and platelets. In general, lower density lipids activate intracellular pathways to increase local and systemic inflammation, monocyte adhesion, endothelial cell dysfunction and apoptosis, and smooth muscle cell proliferation, resulting in foam cell formation and genesis of atherosclerotic plaque. In contrast, higher density lipids prevent or attenuate atherosclerosis. This article is part 1 of a 2-part review, with part 1 focusing on lipid metabolism and the downstream effects of lipids on the development of atherosclerosis, and part 2 on the clinical treatment of dyslipidemia and the role of these drugs for patients with arterial disease exclusive of the coronary arteries.

Chinese Herbal Compounds for the Prevention and Treatment of Atherosclerosis: Experimental Evidence and Mechanisms

Atherosclerosis is a leading cause of disability and death worldwide. Research into the disease has led to many compelling hypotheses regarding the pathophysiology of atherosclerotic lesion formation and the resulting complications such as myocardial infarction and stroke. Herbal medicine has been widely used in China as well as other Asian countries for the treatment of cardiovascular diseases for hundreds of years; however, the mechanisms of action of Chinese herbal medicine in the prevention and treatment of atherosclerosis have not been well studied. In this review, we briefly describe the mechanisms of atherogenesis and then summarize the research that has been performed in recent years regarding the effectiveness and mechanisms of antiatherogenic Chinese herbal compounds in an attempt to build a bridge between traditional Chinese medicine and cellular and molecular cardiovascular medicine.

Apple Peel Supplemented Diet Reduces Parameters of Metabolic Syndrome and Atherogenic Progression in ApoE-/- Mice

Cardiovascular Diseases (CVD) represent about 30% of all causes of death worldwide. The development of CVD is related in many cases with the previous existence of metabolic syndrome (MS). It is known that apple consumption has a cardiovascular protecting effect, containing phenolic compounds with antioxidant effect, which are concentrated in the fruit peel. The objective of this study was to test the effect of apple peel consumption in a murine model of MS and apoE−/− mice. Apple supplemented diets reduced the biochemical parameters (glycaemia, total cholesterol, HDL-cholesterol, LDL-cholesterol, ureic nitrogen, triglycerides, insulin, and asymmetric dimethylarginine (ADMA)) of MS model in CF1 mice significantly. The model apoE−/− mouse was used to evaluate the capacity of the apple peel to revert the progression of the atherogenesis. FD with HAP reverts cholesterol significantly and slows down the progression of the plate diminishing the cholesterol accumulation area. With these results, it can be concluded that the consumption of apple peel reduces several MS parameters and the atherogenic progression in mice.

Atherothrombotic risk in obesity

A link between obesity and coronary artery disease development has been repeatedly proposed, possibly in part due to the development of a proinflammatory and prothrombotic state in obese subjects. Adipocytes secrete numerous hormones and cytokines (adipokines) which influence gene expression and cell functions in endothelial cells, arterial smooth muscle cells, and monocytes/macrophages favouring the development of an atherosclerotic vulnerable plaque. Moreover, the release of such biologically active molecules also promotes endothelial function impairment, disturbs the haemostatic and fibrinolytic systems, and produces alterations in platelet function affecting the initiation, progression, and stabilization of thrombus formation upon atherosclerotic plaque rupture. In this review we will discuss the pathophysiological mechanisms by which obesity contributes to increase atherothrombosis paying special attention to its effects over thrombosis.

Overview of platelet physiology: its hemostatic and nonhemostatic role in disease pathogenesis

Platelets are small anucleate cell fragments that circulate in blood playing crucial role in managing vascular integrity and regulating hemostasis. Platelets are also involved in the fundamental biological process of chronic inflammation associated with disease pathology. Platelet indices like mean platelets volume (MPV), platelets distributed width (PDW), and platelet crit (PCT) are useful as cheap noninvasive biomarkers for assessing the diseased states. Dynamic platelets bear distinct morphology, where α and dense granule are actively involved in secretion of molecules like GPIIb , IIIa, fibrinogen, vWf, catecholamines, serotonin, calcium, ATP, ADP, and so forth, which are involved in aggregation. Differential expressions of surface receptors like CD36, CD41, CD61 and so forth have also been quantitated in several diseases. Platelet clinical research faces challenges due to the vulnerable nature of platelet structure functions and lack of accurate assay techniques. But recent advancement in flow cytometry inputs huge progress in the field of platelets study. Platelets activation and dysfunction have been implicated in diabetes, renal diseases, tumorigenesis, Alzheimer's, and CVD. In conclusion, this paper elucidates that platelets are not that innocent as they keep showing and thus numerous novel platelet biomarkers are upcoming very soon in the field of clinical research which can be important for predicting and diagnosing disease state.

Melatonin and its atheroprotective effects: a review

Atherosclerosis is a chronic vascular disease in which oxidative stress and inflammation are commonly implicated as major causative factors. Identification of novel strategies that contribute to plaque stabilization or inhibition represents a continuing challenge for the medical community. The evidence from the last decade highlights that melatonin influences the cardiovascular system, but its mechanisms of action have not been definitively clarified. Melatonin has atheroprotective effects by acting on different pathogenic signaling processes; these result from its direct free radical scavenger activity, its indirect antioxidant properties and its anti-inflammatory actions. In this review, we summarize the many pieces of the puzzle which identified molecular targets for prevention and therapy against the atherosclerotic pathogenic processes and we evaluate the data documenting that melatonin treatment has important actions that protect against atherosclerosis and atherosclerosis-related cardiovascular diseases.

Protective mechanisms of adenosine 5'-monophosphate in platelet activation and thrombus formation

Platelet activation is relevant to a variety of acute thrombotic events. We sought to examine adenosine 5'-monophosphate (AMP) mechanisms of action in preventing platelet activation, thrombus formation and platelet-related inflammatory response. We assessed the effect of AMP on 1) P-selectin expression and GPIIb/IIIa activation by flow cytometry; 2) Platelet aggregation and ATP secretion induced by ADP, collagen, TRAP-6, convulxin and thrombin; 3) Platelet rolling and firm adhesion, and platelet-leukocyte interactions under flow-controlled conditions; and, 4) Platelet cAMP levels, sP-selectin, sCD40L, IL-1β, TGF-β1 and CCL5 release, PDE3A activity and PKA phosphorylation. The effect of AMP on in vivo thrombus formation was also evaluated in a murine model. The AMP docking with respect to A2 adenosine receptor was determined by homology. AMP concentration-dependently (0.1 to 3 mmol/l) inhibited P-selectin expression and GPIIb/IIIa activation, platelet secretion and aggregation induced by ADP, collagen, TRAP-6 and convulxin, and diminished platelet rolling and firm adhesion. Furthermore, AMP induced a marked increase in the rolling speed of leukocytes retained on the platelet surface. At these concentrations AMP significantly decreased inflammatory mediator from platelet, increased intraplatelet cAMP levels and inhibited PDE3A activity. Interestingly, SQ22536, ZM241385 and SCH58261 attenuated the antiplatelet effect of AMP. Docking experiments revealed that AMP had the same orientation that adenosine inside the A2 adenosine receptor binding pocket. These in vitro antithrombotic properties were further supported in an in vivo model of thrombosis. Considering the successful use of combined antiplatelet therapy, AMP may be further developed as a novel antiplatelet agent.

Atherosclerosis, platelets and thrombosis in acute ischaemic heart disease

Atherosclerosis is the underlying reason for nearly all causes of coronary artery disease and peripheral arterial disease and many cases of stroke. Atherosclerosis is a systemic inflammatory process characterised by the accumulation of lipids and macrophages/lymphocytes within the intima of large arteries. The deposition of these blood borne materials and the subsequent thickening of the wall often significantly compromise the residual lumen leading to ischaemic events distal to the arterial stenosis. However, these initial fatty streak lesions may also evolve into vulnerable plaques susceptible to rupture or erosion. Plaque disruption initiates both platelet adhesion and aggregation on the exposed vascular surface and the activation of the clotting cascade leading to the so-called atherothrombotic process. Yet, platelets have also been shown to be transporters of regulatory molecules (micro-RNA), to drive the inflammatory response and mediate atherosclerosis progression. Here we discuss our current understanding of the pathophysiological mechanisms involved in atherogenesis - from fatty streaks to complex and vulnerable atheromas - and highlight the molecular machinery used by platelets to regulate the atherogenic process, thrombosis and its clinical implications.

Argan oil prevents prothrombotic complications by lowering lipid levels and platelet aggregation, enhancing oxidative status in dyslipidemic patients from the area of Rabat (Morocco)

Background

It is now established that patients with hyperlipidemia have a high risk of atherosclerosis and thrombotic complications, which are two important events responsible for the onset and progression of cardiovascular disease. In the context of managing dyslipidemia by means of dietary advice based on the consumption of argan oil, we wanted to investigate the effect of virgin argan oil on plasma lipids, and for the first time, on the platelet hyperactivation and oxidative status associated with dyslipidemia. This study concerns patients recruited in the area of Rabat in Morocco.

Methods

39 dyslipidemic (79% women) patients were recruited for our study in the area of Rabat in Morocco. They were randomly assigned to the two following groups: the argan group, in which the subjects consumed 25 mL/day of argan oil at breakfast for 3 weeks, and the control group in which argan oil was replaced by butter.

Results

After a 3-week consumption period, blood total cholesterol was significantly lower in the argan oil group, as was LDL cholesterol (23.8% and 25.6% lower, respectively). However, the HDL cholesterol level had increased by 26% at the end of the intervention period compared to baseline. Interestingly, in the argan oil group thrombin-induced platelet aggregation was lower, and oxidative status was enhanced as a result of lower platelet MDA and higher GPx activity, respectively.

Conclusions

In conclusion, our results, even if it is not representative of the Moroccan population, show that argan oil can prevent the prothrombotic complications associated with dyslipidemia, which are a major risk factor for cardiovascular disease.

Lipid-lowering therapy with statins reduces microparticle shedding from endothelium, platelets and inflammatory cells

Hyperlipidaemia is a causal factor in the ethiopathogenesis of atherosclerosis. Statins are the cornerstone drug therapy for LDL-cholesterol (LDL-c) lowering, that exert beneficial effects beyond lipid lowering. Circulating microparticles (cMPs), microvesicles released by activated cells into the bloodstream, are markers of vascular and inflammatory cell activation with tentative role in disease progression. However, the role of statins on cMPs seems controversial. We aimed at the evaluation of the effects of lipid-lowering treatment (LLT) on cMP generation in patients in primary prevention of atherosclerosis. A case-control study was conducted in hypercholesterolaemic patients receiving LLT with statins and normocholesterolaemic controls (LLT+ and LLT-, respectively, n=37/group), matched by age, gender and LDL-c levels. cMPs were characterised by flow cytometry using annexin-V and cell-specific antibodies. In LLT+-patients overall numbers of cMPs (p<0.005) were lower than in controls. Levels of cMPs carrying parental cell markers from vascular and circulating cell origin (platelet, endothelial cell, pan-leukocyte and specific-leukocyte subsets) were significantly lower in blood of LLT+ compared to LLT--patients. Moreover, MPs from LLT+-patients had reduced markers of activated platelets (αIIbβ3-integrin), activated inflammatory cells (αM-integrin) and tissue factor. The effect of LLT on cMP shedding was found to be accumulative in years. cMP shedding associated to cardiovascular risk in LLT+-patients. In summary, at similar plasma cholesterol levels patients on statin treatment had a significant lower number of cMPs carrying markers of activated cells. These findings indicate that statins protect against vascular cell activation.

High-density lipoproteins and myocardial necrosis in patients with acute myocardial infarction and ST segment elevation

INTRODUCTION AND AIM

Low plasma levels of high-density lipoprotein cholesterol (HDLC) is a prognostic factor in patients with acute coronary syndrome. The aim of this study was to evaluate the relationship between HDLC and myocardial necrosis estimated by cardiac magnetic resonance (CMR) in patients with acute ST-segment elevation myocardial infarction (STEMI) and reperfusion strategy.

METHODS

Retrospective analysis of 139 patients (mean age 59.8 years; 79% men) admitted with STEMI who underwent a CMR in the first week.

RESULTS

With a comparable reperfusion strategy used and time of ischemia, patients with HDLC ≤40 mg/dl (69% of total) had more extensive areas of myocardial necrosis after STEMI, in number of segments with late gadolinium enhancement (RTG) with transmural necrosis pattern (4.7 vs. 2.1%, p < .001) and in percentage of RTG with respect to total mass myocardial (18.2 vs. 11.3%, p < .01), and worst left ventricular ejection fraction (LVEF) (49.7 vs. 57.2%, p < .001).

CONCLUSIONS

We conclude that low HDLC are very common in patients with STEMI and associated with increased necrosis and a worse LVEF in the CRM study.

Platelets and atherogenesis: Platelet anti-aggregation activity and endothelial protection from tomatoes (Solanum lycopersicum L.)

In recent years, it has been shown that platelets are not only involved in the arterial thrombotic process, but also that they play an active role in the inflammatory process of atherogenesis from the beginning. The interaction between platelets and endothelial cells occurs in two manners: activated platelets unite with intact endothelial cells, or platelets in resting adhere to activated endothelium. In this context, inhibition of the platelet function (adhesion/aggregation) could contribute to the prevention of atherothrombosis, the leading cause of cardiovascular morbidity. This can be achieved with antiplatelet agents. However, at the public health level, the level of primary prevention, a healthy diet has also been shown to exert beneficial effects. Among those elements of a healthy diet, the consumption of tomatoes (Solanum lycopersicum L.) stands out for its effect on platelet anti-aggregation activity and endothelial protection, which may be beneficial for cardiovascular health. This article briefly discusses the involvement of platelets in atherogenesis and the possible mechanisms of action provided by tomatoes for platelet anti-aggregation activity and endothelial protection.

Extracorporeal assays of thrombosis

Platelet deposition, adhesion/aggregation, to the damaged vessel wall or atherosclerotic plaque components has shown to play a major role in hemostasis, thrombosis, and the development of atherosclerosis. Platelet-vessel wall interaction and thrombus formation is driven by blood flow rheology/hemodynamics (changes in local flow conditions), the nature of the flowing blood, and the characteristics of the triggering substrate (lesion type). An extracorporeal perfusion system (the Badimon chamber) was developed to investigate the dynamics of platelet deposition and thrombus formation on: (a) different surfaces (biological and synthetic); (b) under controlled blood flow conditions with varying degrees of stenosis mimicking various vascular conditions (patent and stenotic arteries); and (c) with varying perfusing blood treatments. In the following chapter, we thoroughly describe this experimental approach that has helped to improve the understanding of the pathophysiology of the acute coronary syndromes (Badimon et al., Arteriosclerosis 6:312-320, 1986; Badimon et al., J Lab Clin Med 110:706-718, 1987; Badimon et al., Blood 73:961-967, 1989; Mailhac et al., Circulation 90:988-996, 1994) and is a useful tool for the study and screening of new antithrombotic and platelet-inhibitory compounds (Badimon et al., Thromb Haemost 71:511-516, 1994; Vilahur et al., Circulation 110:1686-1693; Vilahur et al., Thromb Haemost 92:191-200, 2004; Vilahur et al., Cardiovasc Res 61:806-816; Vilahur et al., Thromb Haemost 98:662-669, 2007; Vilahur et al., Thromb Haemost 97:650-657, 2007; Zafar et al., J Thromb Haemost 5:1195-1200, 2007; Lev et al., J Am Coll Cardiol 43:966-971) and for the evaluation of the thrombogenicity associated to synthetic/prosthetic surfaces (Badimon et al., J Biomater Appl 5:27-48, 1990; Badimon et al., ASAIO Trans 33:621-625, 1987) and/or plasma components (cholesterol, glucose levels, etc.) (Badimon et al., Arterioscler Thromb 11:395-402, 1991; Osende et al., J Am Coll Cardiol 38:1307-1312; 2001).

Characterization of the cytokine profile of platelet rich plasma (PRP) and PRP-induced cell proliferation and migration: Upregulation of matrix metalloproteinase-1 and -9 in HaCaT cells

Background

The underlying rationale of platelet rich plasma (PRP) therapy is that an injection of concentrated PRP at the site of injury may promote tissue repair via cytokine release from platelets. The molecular mechanisms of PRP therapy in the skin wound healing process are not well understood at present, and would benefit from clarification.

Methods

PRP was stimulated with angonists for 5 min, and cytokine profile analysis was performed. To investigate the wound healing activity of PRP, cell proliferation and migration analyses were performed in skin cells. The effects of PRP were analyzed on the expression and activity of matrix metalloproteinase (MMP)-1, -2, -9, and the activation of transcription factors.

Results

Thrombin was found to be a strong stimulator of PRP activation to release growth factors and chemokines. PRP induced cell proliferation and migration in HUVECs, HaCaT cells, and HDFs, as well as MMP-1and MMP-9 expression in HaCaT cells, but PRP did not have a significant effect on the expression or activity of MMPs in HDFs. The transcription factors, including signal transducer and activator of transcription-3 (STAT-3) were found to be phosphorylated following PRP treatment in HaCaT cells.

Conclusion

In this study, we have identified the cytokine profile of activated PRP after agonist stimulation. We have shown that PRP plays an active role in promoting the proliferation and migration of skin cells via the regulation of MMPs, and this may be applicable to the future development of PRP therapeutics to enhance skin wound healing.

Low levels of high-density lipoproteins cholesterol are independently associated with acute coronary heart disease in patients hospitalized for chest pain

INTRODUCTION AND OBJECTIVES

The role of high-density lipoproteins in the context of acute chest pain has not been well characterized. The objective of this study was to determine the relative contribution of lipid profile to the risk of acute coronary syndrome in patients admitted to a cardiology ward for chest pain.

METHODS

We included all consecutive admissions in a single cardiology department over a period of 10 months and 1-year follow-up was performed.

RESULTS

In total, 959 patients were included: 457 (47.7%) were diagnosed with non-ischemic chest pain, 355 (37%) with non-ST-elevation acute coronary syndrome, and 147 (15.3%) with ST-elevation acute coronary syndrome. Prevalence of high-density lipoproteins <40 mg/dL was 54.6%, and was higher in patients with acute coronary syndrome (69.4% vs 30.6%; P<.01). The prevalence of acute coronary syndrome increased with reductions in mean high-density lipoproteins. Age, active smoking, diabetes, fasting glucose >100 mg/dL, and high-density lipoproteins <40 mg/dL were independently associated with acute coronary syndrome, and low high-density lipoproteins was the main associated factor (odds ratio, 4.11; 95% confidence interval, 2.87-5.96). Survival analysis determined that, compared with non-ischemic chest pain, the presence of acute coronary syndrome was associated with significantly greater risk of all-cause and cardiovascular mortality.

CONCLUSIONS

Low levels of high-density lipoproteins cholesterol (≤40 mg/dL) were independently associated with a diagnosis of acute coronary syndrome in patients hospitalized for chest pain, with an inverse relationship between lower levels of high-density lipoproteins and prevalence of acute coronary syndrome.

Update on lipids, inflammation and atherothrombosis

Atherosclerosis is an inflammatory disease that involves the arterial wall and is characterised by the progressive accumulation of lipids in the vessel wall. The first step is the internalisation of lipids (LDL) in the intima with endothelial activation which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. These events increase LDL particles accumulation in the extracellular matrix where they aggregate/fuse, are retained by proteoglycans and become targets for oxidative and enzymatic modifications. In turn, retained pro-atherogenic LDLs enhance selective leukocyte recruitment and attachment to the endothelial layer inducing their transmigration across the endothelium into the intima. While smooth muscle cell numbers decline with the severity of plaque progression, monocytes differentiate into macrophages, a process associated with the upregulation of pattern recognition receptors including scavenger receptors and Toll-like receptors leading to foam cell formation. Foam cells release growth factors, cytokines, metalloproteinases and reactive oxygen species all of which perpetuate and amplify the vascular remodelling process. In addition, macrophages release tissue factor that, upon plaque rupture, contributes to thrombus formation. Smooth muscle cells exposed in eroded lesions are also able to internalise LDL through LRP-1 receptors acquiring a pro-thrombotic phenotype and releasing tissue factor. Platelets recognise ligands in the ruptured or eroded atherosclerotic plaque, initiate platelet activation and aggregation leading to thrombosis and to the clinical manifestation of the atherothrombotic disease. Additionally, platelets contribute to the local inflammatory response and may also participate in progenitor cell recruitment.

Atherosclerosis and thrombosis: insights from large animal models

Atherosclerosis and its thrombotic complications are responsible for remarkably high numbers of deaths. The combination of in vitro, ex vivo, and in vivo experimental approaches has largely contributed to a better understanding of the mechanisms underlying the atherothrombotic process. Indeed, different animal models have been implemented in atherosclerosis and thrombosis research in order to provide new insights into the mechanisms that have already been outlined in isolated cells and protein studies. Yet, although no model completely mimics the human pathology, large animal models have demonstrated better suitability for translation to humans. Indeed, direct translation from mice to humans should be taken with caution because of the well-reported species-related differences. This paper provides an overview of the available atherothrombotic-like animal models, with a particular focus on large animal models of thrombosis and atherosclerosis, and examines their applicability for translational research purposes as well as highlights species-related differences with humans.

Ellagitannins, ellagic acid and vascular health

Hydrolysable tannins are phenolic phytochemicals that show high antioxidant and free-radical scavenging activities. For this reason their potential effects preventing oxidative related diseases, such as cardiovascular diseases, have been largely studied. In vitro studies show that ellagitannins, at concentrations in the range 10-100 μM, show some relevant anti-atherogenic, anti-thrombotic, anti-inflammatory and anti-angiogenic effects, supporting the molecular mechanisms for the vascular health benefits. While there is good evidence supporting the vascular effects in vitro, the evidence on animal models or humans is much scarcer. The in vitro results often do not match the findings in the in vivo studies. This could be explained by the low bioavailability of the antioxidant ellagitannins and ellagic acid. The main ellagitannin metabolites circulating in plasma are ellagic acid microbiota metabolites known as urolithins, and they have lost their free-radical scavenging activity. They are present in plasma as glucuronide or sulphate conjugates, at concentrations in the nM range. Future studies should focus in the bioavailable metabolites, urolithins, and in the form (conjugated with glucuronic acid or sulphate) and concentrations (nM range) in which they are found in plasma. In this review we critically discuss the role of ellagitannins and ellagic acid on vascular health.

Protein kinase C-eta and phospholipase D2 pathway regulates foam cell formation via regulator of G protein signaling 2

Regulator of G protein signaling 2 (RGS2) is a GTPase-activating protein for Galpha(q), which is involved in regulating various vascular functions. To understand how RGS2 regulates foam cell formation, the present study identified signaling pathways controlled by lipopolysaccharide (LPS) and discovered new mechanisms whereby protein kinase C (PKC)-eta and phospholipase D (PLD) 2 regulate RGS2 expression. The toll-like receptor (TLR) 4 agonist LPS caused foam cell formation of Raw264.7 macrophages and dramatically decreased RGS2 mRNA expression. RGS2 down-regulation by LPS was partially recovered by TLR4 small interfering RNA (siRNA). Peritoneal macrophages were separated from wild-type and TLR4 mutant mice, and treatment with LPS showed RGS2 expression decrease in wild-type macrophages but no change in TLR4 mutant macrophages. RGS2 overexpression was suppressed, whereas RGS2 down-regulation accelerated foam cell formation by LPS. Treatment of PKC-eta pseudosubstrate weakened foam cell formation and recovered RGS2 down-regulation by LPS. In addition, LPS or phorbol 12-myristate 13-acetate stimulated PLD activity, and the pretreatment of PLD inhibitor weakened foam cell formation and recovered RGS2 down-regulation. Inhibition of PLD2 expression by siRNA also weakened foam cell formation and partially recovered LPS-mediated RGS2 down-regulation. On the other hand, PLD2 overexpression intensified RGS2 down-regulation and foam cell formation by LPS. These results suggest that LPS causes foam cell formation by increasing PKC-eta and PLD2 activity by down-regulating RGS2 expression via TLR4 dependently.

Antioxidant and antiatherogenic activities of pentacyclic triterpenic diols and acids

The present paper aimed to test the potential cardioprotective activity of four pentacyclic triterpenes, uvaol, erythrodiol, oleanolic acid and maslinic acid, widely distributed throughout the vegetable kingdom. For this purpose, their antioxidant and antithrombotic activities related to LDL particles have been in vitro evaluated. Results demonstrated that maslinic acid, uvaol and erythrodiol exert antiatherogenic effect while no effect was observed for oleanolic acid. Specifically, maslinic acid has shown the most potent dose-dependent antioxidant effect and did not have antithrombotic properties, whereas uvaol and erythrodiol exhibited both antioxidant and antithrombotic activities. In addition, antioxidant mechanisms of action were determined. While maslinic acid possesses dual activity acting as scavenger of free radicals and as copper chelator, uvaol is able to form a complex with copper and erythrodiol seems to behave as a retarder antioxidant. In conclusion, dietary triterpenes may exert a cardioprotective effect by different mechanisms of action related to antioxidant and antithrombotic activities.