Effect of milk fat on LDL cholesterol and other cardiovascular risk markers in healthy humans: the INNOVALAIT project.

Background: Milk has a specific saturated fatty acid profile and its calcium content may change the kinetics of fat absorption.

Objective: The goal of this study was to compare the effect on LDL Cholesterol and other risk markers of four isolipidic diets differing by their fat food source, vegetable fat, spring milk fat, winter milk fat or winter milk fat supplemented with calcium, in healthy moderately hypercholesterolemic humans.

Individuals And Methods: This double-blind, randomized trial with four parallel arms included 172 healthy adults with plasma LDL cholesterol (LDL-C) from 130 to 220 mg/dL and triglycerides below 300 mg/dL.

The Tumor Suppressor SASH1 Interacts With the Signal Adaptor CRKL to Inhibit Epithelial-Mesenchymal Transition and Metastasis in Colorectal Cancer.

Background & Aims: The tumor-suppressor sterile α motif- and Src-homology 3-domain containing 1 (SASH1) has clinical relevance in colorectal carcinoma and is associated specifically with metachronous metastasis. We sought to identify the molecular mechanisms linking decreased expression with distant metastasis formation.

Methods: SASH1-deficient, SASH1-depleted, or SASH1-overexpressing HCT116 colon cancer cells were generated by the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9-method, RNA interference, and transient plasmid transfection, respectively.

Role of lipid phosphate phosphatase 3 in human aortic endothelial cell function.

Aims: Lipid phosphate phosphatase 3; type 2 phosphatidic acid phosphatase β (LPP3; PPAP2B) is a transmembrane protein dephosphorylating and thereby terminating signalling of lipid substrates including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P). Human LPP3 possesses a cell adhesion motif that allows interaction with integrins. A polymorphism (rs17114036) in PPAP2B is associated with coronary artery disease, which prompted us to investigate the possible role of LPP3 in human endothelial dysfunction, a condition promoting atherosclerosis.

Plasma PAFAH/PLA2G7 Genetic Variability, Cardiovascular Disease, and Clinical Trials.

PAFAH is specific for short acyl groups esterified at the sn-2 position of glycerol in phospholipids, and apart from PAF, it hydrolyzes oxidized phospholipids produced during LDL oxidation. As the majority of the plasma PAFAH activity is bound in humans to LDL, it is also called the lipoprotein-associated phospholipase A2 (Lp-PLA2), and it was associated with the proinflammatory processes in atherosclerosis. The epidemiological studies in Caucasian populations demonstrated that high PAFAH levels might be a risk factor for cardiovascular disease through generation of proinflammatory lysoPC/lysoPAF and oxidized fatty free acids and led to the development of darapladib, a reversible PAFAH inhibitor.

SASH1, a new potential link between smoking and atherosclerosis.

Objective: We have previously reported that SASH1 expression is increased in circulating human monocytes from smokers and was positively correlated with the number of carotid atherosclerotic plaques. The aim of this study was to further validate the link between smoking, SASH1 and atherosclerosis within the vascular wall and to assess the impact of SASH1 expression on endothelial cell functions.

Method: Human carotids with atherosclerotic plaques were obtained from 58 patients (45 of them with known smoking status: smoker, non-smoker, ex-smokers), and were processed for gene expression analyses and immunostaining.

Bariatric Surgery Induces Disruption in Inflammatory Signaling Pathways Mediated by Immune Cells in Adipose Tissue: A RNA-Seq Study.

Background: Bariatric surgery is associated to improvements in obesity-associated comorbidities thought to be mediated by a decrease of adipose inflammation. However, the molecular mechanisms behind these beneficial effects are poorly understood.

Methodology/principal Findings: We analyzed RNA-seq expression profiles in adipose tissue from 22 obese women before and 3 months after surgery.

PLA2G10 Gene Variants, sPLA2 Activity, and Coronary Heart Disease Risk.

Background: Observational studies report that secretory phospholipase A2 (sPLA2) activity is a marker for coronary heart disease (CHD) risk, and activity measures are thought to represent the composite activity of sPLA2-IIA, -V, and -X. The aim of this study was to use genetic variants of PLA2G10, encoding sPLA2-X, to investigate the contribution of sPLA2-X to the measure of sPLA2 activity and coronary heart disease (CHD) risk traits and outcome.

Methods And Results: Three PLA2G10 tagging single-nucleotide polymorphisms (rs72546339, rs72546340, and rs4003232) and a previously studied PLA2G10 coding single-nucleotide polymorphism rs4003228, R38C, were genotyped in a nested case: control cohort drawn from the prospective EPIC-Norfolk Study (2175 cases and 2175 controls).

Induction of dendritic cell-mediated T-cell activation by modified but not native low-density lipoprotein in humans and inhibition by annexin a5: involvement of heat shock proteins.

Objective: Atherosclerosis is an inflammatory disease, where activated immunocompetent cells, including dendritic cells (DCs) and T cells are abundant in plaques. Low-density lipoprotein modified either by oxidation (oxLDL) or by human group X-secreted phospholipase A2 (LDLx) and heat shock proteins (HSP), especially HSP60 and 90, have been implicated in atherosclerosis. We previously reported that Annexin A5 inhibits inflammatory effects of phospholipids, decreases vascular inflammation and improves vascular function in apolipoprotein E(-/-) mice.

Graphical modeling of gene expression in monocytes suggests molecular mechanisms explaining increased atherosclerosis in smokers.

Smoking is a risk factor for atherosclerosis with reported widespread effects on gene expression in circulating blood cells. We hypothesized that a molecular signature mediating the relation between smoking and atherosclerosis may be found in the transcriptome of circulating monocytes. Genome-wide expression profiles and counts of atherosclerotic plaques in carotid arteries were collected in 248 smokers and 688 non-smokers from the general population.

The nuclear hormone receptor PPARγ counteracts vascular calcification by inhibiting Wnt5a signalling in vascular smooth muscle cells.

Vascular calcification is a hallmark of advanced atherosclerosis. Here we show that deletion of the nuclear receptor PPARγ in vascular smooth muscle cells of low density lipoprotein receptor (LDLr)-deficient mice fed an atherogenic diet high in cholesterol, accelerates vascular calcification with chondrogenic metaplasia within the lesions. Vascular calcification in the absence of PPARγ requires expression of the transmembrane receptor LDLr-related protein-1 in vascular smooth muscle cells.

Circulating levels of secretory- and lipoprotein-associated phospholipase A2 activities: relation to atherosclerotic plaques and future all-cause mortality.

Aims: Secretory- and lipoprotein-associated phospholipases A2 (sPLA2 and Lp-PLA2) are enzymes both suggested to be of importance for atherosclerosis. We investigated relationships between the activities of these enzymes in the circulation and atherosclerosis as well as future clinical events.

Methods And Results: The population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study included 1016 randomly selected subjects, all aged 70.

Human group X secreted phospholipase A2 induces dendritic cell maturation through lipoprotein-dependent and -independent mechanisms.

Objective: Increased secreted phospholipase A(2) (sPLA(2)) activity has been documented in several inflammatory disorders. Among sPLA(2)s, the human group X (hGX)-sPLA(2) has the highest catalytic activity towards phosphatidylcholine (PC), the major phospholipid of cell membranes and blood lipoproteins. hGX-sPLA(2) has been detected in human atherosclerotic lesions, indicating that sPLA(2)s are an important link between lipids and inflammation, both involved in atherosclerosis.

Genetic and environmental regulation of inflammatory CVD biomarkers Lp-PLA2 and IgM anti-PC.

Objective: We set out to investigate the relative contribution of genetic and environmental effect on two inflammatory CVD biomarkers; lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and anti-phosphorylcholine IgM (anti-PC). Their relationships and possible co-regulation with other established CVD biomarkers are also examined.

Methods: Lp-PLA(2) activity (N=1600) and anti-PC (N=2036) levels were measured in elderly Swedish twins.

Antagonistic regulation of macrophage phenotype by M-CSF and GM-CSF: implication in atherosclerosis.

Objectives: We characterized the transcriptional profiles of GM-CSF- (GM-MØ) and M-CSF-induced macrophages (M-MØ) and investigated in situ a subset of differentially expressed genes in human and mouse atherosclerotic lesions.

Methods And Results: Using microarrays we identified a number of genes and biological processes differentially regulated in M-MØ vs GM-MØ. By varying in culture the M-CSF/GM-CSF ratio (0-10), a spectrum of macrophage phenotypes was explored by RT-QPCR.

PLA2G7 genotype, lipoprotein-associated phospholipase A2 activity, and coronary heart disease risk in 10 494 cases and 15 624 controls of European Ancestry.

Background: Higher lipoprotein-associated phospholipase A(2)(Lp-PLA2) activity is associated with increased risk of coronary heart disease (CHD), making Lp-PLA2 a potential therapeutic target. PLA2G7 variants associated with Lp-PLA2 activity could evaluate whether this relationship is causal.

Methods And Results: A meta-analysis including a total of 12 studies (5 prospective, 4 case-control, 1 case-only, and 2 cross-sectional studies; n=26 118) was undertaken to examine the association of the following: (1) Lp-PLA2 activity versus cardiovascular biomarkers and risk factors and CHD events (2 prospective studies; n=4884); (2) PLA2G7 single-nucleotide polymorphisms and Lp-PLA2 activity (3 prospective, 2 case-control, 2 cross-sectional studies; up to n=6094); and (3) PLA2G7 single-nucleotide polymorphisms and angiographic coronary artery disease (2 case-control, 1 case-only study; n=4971 cases) and CHD events (5 prospective, 2 case-control studies; n=5523).

Phospholipolyzed LDL induces an inflammatory response in endothelial cells through endoplasmic reticulum stress signaling.

Secreted phospholipases A2 (sPLA2s) are present in atherosclerotic plaques and are now considered novel attractive therapeutic targets and potential biomarkers as they contribute to the development of atherosclerosis through lipoprotein-dependent and independent mechanisms. We have previously shown that hGX-sPLA2-phospholipolyzed LDL (LDL-X) induces proinflammatory responses in human umbilical endothelial cells (HUVECs); here we explore the molecular mechanisms involved. Global transcriptional gene expression profiling of the response of endothelial cells exposed to either LDL or LDL-X revealed that LDL-X activates multiple distinct cellular pathways including the unfolded protein response (UPR).

A follow-up study of a genome-wide association scan identifies a susceptibility locus for venous thrombosis on chromosome 6p24.1.

To identify genetic susceptibility factors conferring increased risk of venous thrombosis (VT), we conducted a multistage study, following results of a previously published GWAS that failed to detect loci for developing VT. Using a collection of 5862 cases with VT and 7112 healthy controls, we identified the HIVEP1 locus on chromosome 6p24.1 as a susceptibility locus for VT.

Extracellular phospholipases in atherosclerosis.

Phospholipases A2 (PLA2) are a family of enzymes that catalyze the hydrolysis of the sn-2 ester bond of glycerophospholipids liberating lysophospholipids and free fatty acids; important second messengers involved in atherogenesis. Plasma PAF-acetylhydrolase (PAF-AH) or Lp-PLA2 is a Ca(2+)-independent PLA2 which is produced by monocyte-derived macrophages and by activated platelets, and circulates in plasma associated with lipoproteins. PAF-AH catalyzes the removal of the acetyl/short acyl group at the sn-2 position of PAF and oxidized phospholipids produced during inflammation and oxidative stress.

Increased PAFAH and oxidized lipids are associated with inflammation and atherosclerosis in hypercholesterolemic pigs.

Objective: To study the association of PAF-acetyl hydrolase (PAFAH) activity with inflammation, oxidative stress, and atherosclerosis in hypercholesterolemic swine.

Methods And Results: Cholesterol-rich diet feeding of miniature pigs was associated with an increase in PAFAH activity and an increase of the PAFAH to PON1 ratio. PLA2G7 RNA (coding for PAFAH) expression was increased in blood monocytes and plaque macrophages.

Molecular and functional characterization of polymorphisms in the secreted phospholipase A2 group X gene: relevance to coronary artery disease.

Among secreted phospholipases A2 (sPLA2s), human group X sPLA2 (hGX sPLA2) is emerging as a novel attractive therapeutic target due to its implication in inflammatory diseases. To elucidate whether hGX sPLA2 plays a causative role in coronary artery disease (CAD), we screened the human PLA2G10 gene to identify polymorphisms and possible associations with CAD end-points in a prospective study, AtheroGene. We identified eight polymorphisms, among which, one non-synonymous polymorphism R38C in the propeptide region of the sPLA2.

Inflammatory biomarkers, physical activity, waist circumference, and risk of future coronary heart disease in healthy men and women.

Aims: The aim of this study was to determine the contribution of physical activity and abdominal obesity to the variation in inflammatory biomarkers and incident coronary heart disease (CHD) in a European population.

Methods And Results: In a prospective case-control study nested in the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort, we examined the associations between circulating levels or activity of C-reactive protein, myeloperoxidase (MPO), secretory phospholipase A2 (sPLA2), lipoprotein-associated phospholipase A2 (Lp-PLA2), fibrinogen, adiponectin, waist circumference, physical activity, and CHD risk over a 10-year period among healthy men and women (45-79 years of age). A total of 1002 cases who developed fatal or non-fatal CHD were matched to 1859 controls on the basis of age, sex, and enrolment period.

Platelet-activating factor acetylhydrolase and transacetylase activities in human aorta and mammary artery.

Platelet-activating factor (PAF), the potent phospholipid mediator of inflammation, is involved in atherosclerosis. Platelet-activating factor-acetylhydrolase (PAF-AH), the enzyme that inactivates PAF bioactivity, possesses both acetylhydrolase and transacetylase activities. In the present study, we measured acetylhydrolase and transacetylase activities in human atherogenic aorta and nonatherogenic mammary arteries.

Increased oxidative stress in scavenger receptor BI knockout mice with dysfunctional HDL.

Objective: In the current study the effect of disruption of SR-BI, a prominent regulator of HDL metabolism, on the activity of the HDL-associated antioxidant enzymes PON1 and PAF-AH as well as in vivo oxidative stress were investigated.

Methods And Results: SR-BI deficiency resulted in 1.4-fold (P<0.

High pressure promotes monocyte adhesion to the vascular wall.

Hypertension is a known risk factor for the development of atherosclerosis. To assess how mechanical factors contribute to this process, mouse carotid arteries were maintained in organ culture at normal (80 mm Hg) or high (150 mm Hg) intraluminal pressure for 1, 6, 12, or 24 hours. Thereafter, fluorescent human monocytic cells (U937) were injected intraluminally and allowed to adhere for 30 minutes before washout.

Atherogenic properties of LDL particles modified by human group X secreted phospholipase A2 on human endothelial cell function.

Increasing evidence suggests that secreted phospholipases A2 (sPLA2s) play an important role in the pathophysiology of atherosclerosis. Among sPLA2s, the human group X (hGX) enzyme has the highest catalytic activity toward phosphatidylcholine, one of the major phospholipid species of cell membranes and low-density lipoprotein (LDL). Our study examined the presence of hGX sPLA2 in human atherosclerotic lesions and investigated the ability of hGX modified LDL to alter human endothelial cell (HUVEC) function.