Fish consumption is considered health beneficial as it decreases cardiovascular disease (CVD)-risk through effects on plasma lipids and inflammation. We investigated a salmon protein hydrolysate (SPH) that is hypothesized to influence lipid metabolism and to have anti-atherosclerotic and anti-inflammatory properties. 24 female apolipoprotein (apo) E−/− mice were divided into two groups and fed a high-fat diet with or without 5% (w/w) SPH for 12 weeks. The atherosclerotic plaque area in aortic sinus and arch, plasma lipid profile, fatty acid composition, hepatic enzyme activities and gene expression were determined. A significantly reduced atherosclerotic plaque area in the aortic arch and aortic sinus was found in the 12 apoE−/− mice fed 5% SPH for 12 weeks compared to the 12 casein-fed control mice. Immunohistochemical characterization of atherosclerotic lesions in aortic sinus displayed no differences in plaque composition between mice fed SPH compared to controls. However, reduced mRNA level of Icam1 in the aortic arch was found. The plasma content of arachidonic acid (C20∶4n-6) and oleic acid (C18∶1n-9) were increased and decreased, respectively. SPH-feeding decreased the plasma concentration of IL-1β, IL-6, TNF-α and GM-CSF, whereas plasma cholesterol and triacylglycerols (TAG) were unchanged, accompanied by unchanged mitochondrial fatty acid oxidation and acyl-CoA:cholesterol acyltransferase (ACAT)-activity. These data show that a 5% (w/w) SPH diet reduces atherosclerosis in apoE−/− mice and attenuate risk factors related to atherosclerotic disorders by acting both at vascular and systemic levels, and not directly related to changes in plasma lipids or fatty acids.
Atherosclerosis is a major cause of cerebrovascular disease. Matrix metalloproteinases (MMPs) play an important role in matrix degradation within the atherosclerotic lesion leading to plaque destabilization and ischemic stroke. We hypothesized that MMP-7 could be involved in this process.
Plasma levels of MMP-7 were measured in 182 consecutive patients with moderate (50–69%) or severe (≥70%) internal carotid artery stenosis, and in 23 healthy controls. The mRNA levels of MMP-7 were measured in atherosclerotic carotid plaques with different symptomatology, and based on its localization to macrophages, the in vitro regulation of MMP-7 in primary monocytes was examined.
Our major findings were (i) Patients with carotid atherosclerosis had markedly increased plasma levels of MMP-7 compared to healthy controls, with particularly high levels in patients with recent symptoms (i.e., within the last 2 months). (ii) A similar pattern was found within carotid plaques with markedly higher mRNA levels of MMP-7 than in non-atherosclerotic vessels. Particularly high protein levels of MMP-7 levels were found in those with the most recent symptoms. (iii) Immunhistochemistry showed that MMP-7 was localized to macrophages, and in vitro studies in primary monocytes showed that the inflammatory cytokine tumor necrosis factor-α in combination with hypoxia and oxidized LDL markedly increased MMP-7 expression. (iv) During the follow-up of patients with carotid atherosclerosis, high plasma levels of MMP-7 were independently associated with total mortality.
Our findings suggest that MMP-7 could contribute to plaque instability in carotid atherosclerosis, potentially involving macrophage-related mechanisms.
Tetradecylthioacetic acid (TTA) is a hypolipidemic antioxidant with immunomodulating properties involving activation of peroxisome proliferator-activated receptors (PPARs) and proliferation of mitochondria. This study aimed to penetrate the effect of TTA on the development of atherosclerotic lesions in apolipoprotein (apo)-E-/- mice fed a high-fat diet containing 0.3% TTA for 12 weeks. These mice displayed a significantly less atherosclerotic development vs control. Plasma cholesterol was increased by TTA administration and triacylglycerol (TAG) levels in plasma and liver were decreased by TTA supplementation, the latter, probably due to increased mitochondrial fatty acid oxidation and reduced lipogenesis. TTA administration also changed the fatty acid composition in the heart, and the amount of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) was reduced and increased, respectively. The heart mRNA expression of inducible nitric oxidase (NOS)-2 was decreased in TTA-treated mice, whereas the mRNA level of catalase was increased. Finally, reduced plasma levels of inflammatory mediators as IL-1α, IL-6, IL-17, TNF-α and IFN-γ were detected in TTA-treated mice. These data show that TTA reduces atherosclerosis in apoE-/- mice and modulates risk factors related to atherosclerotic disorders. TTA probably acts at both systemic and vascular levels in a manner independent of changes in plasma cholesterol, and triggers TAG catabolism through improved mitochondrial function.
Epidemiological studies have shown that low plasma levels of high-density lipoprotein (HDL) cholesterol are associated with increased risk of cardiovascular disease, but the mechanisms for the possible atheroprotective effects of HDL cholesterol have still not been fully clarified, in particular in relation to clinical studies.
To examine the inflammatory, anti-oxidative and metabolic phenotype of subjects with low plasma HDL cholesterol levels.
Methods and Results
Fifteen subjects with low HDL cholesterol levels (eleven males and four females) and 19 subjects with high HDL (three males and 16 females) were recruited. Low HDL cholesterol was defined as ≤10th age/sex specific percentile and high HDL-C was defined as ≥90 age/sex specific percentile. Inflammatory markers in circulation and PBMC gene expression of cholesterol efflux mediators were measured. Our main findings were: (i) subjects with low plasma HDL cholesterol levels were characterized by increased plasma levels of CRP, MMP-9, neopterin, CXCL16 and ICAM-1 as well as low plasma levels of adiponectin, suggesting an inflammatory phenotype; (ii) these individuals also had reduced paraoxonase (PON)1 activity in plasma and PON2 gene expression in peripheral blood mononuclear cells (PBMC) accompanied by increased plasma levels of oxidized LDL suggesting decreased anti-oxidative capacity; and (iii) PBMC from low HDL subjects also had decreased mRNA levels of ABCA1 and ABCG1, suggesting impaired reverse cholesterol transport.
Subjects with low plasma HDL cholesterol levels are characterized by an inflammatory and oxidative phenotype that could contribute to the increased risk of atherosclerotic disorders in these subjects with low HDL levels.
Atherosclerosis is a chronic inflammatory disorder that involves a range of inflammatory mediators. Although interleukin (IL)-9 has been related to inflammation, there are at present no data on its role in atherosclerosis. Here we have examined IL-9 and IL-9 receptor (IL-9R) systemically and locally in patients with coronary and carotid atherosclerosis.
Plasma IL-9 was quantified by enzyme immunoassay and multiplex technology. IL-9 and IL-9R mRNA were quantified by real-time RT-PCR, and their localization within the lesion was assessed by immunohistochemistry.
The main findings were: (i) Patients with carotid atherosclerosis had significantly raised IL-9 plasma levels compared with healthy controls (n = 28), with no differences between asymptomatic (n = 56) and symptomatic (n = 88) patients. (ii) On admission, patients with acute ST-elevation myocardial infarction (STEMI) (n = 42) had markedly raised IL-9 plasma levels which gradually declined during the first week post-MI. (iii) T cells and monocytes from patients with unstable angina (n = 17) had increased mRNA levels of IL-9 as compared with controls (n = 11). (iv) Carotid plaques (n = 68) showed increased mRNA levels of IL-9 and IL-9R compared to non-atherosclerotic vessels (n = 10). Co-localization to T cells (IL-9 and IL-9R) and macrophages (IL-9) were shown by immunohistochemistry. (v) IL-9 increased IL-17 release in peripheral blood mononuclear cells from patients with unstable angina (n = 5) and healthy controls (n = 5) with a particularly enhancing effect in cells from the patient group.
Our findings show increased IL-9 levels in different atherosclerotic disorders both systemically and within the lesion, suggesting a role for the IL-9/IL-9R axis in the atherosclerotic process, potentially involving IL-17 mediated mechanisms. However, the functional consequences of these findings should be further investigated.
Unlike conventional dendritic cells (cDC), plasmacytoid DCs (pDC) are poor in antigen presentation and critical for type I interferon response. While proposed to be present in human atherosclerotic lesions, their role in atherosclerosis remains elusive.
To investigate the role of pDC in atherosclerosis.
Methods and Results
We show that pDC are scarcely present in human atherosclerotic lesions, and almost absent in mouse plaques. Surprisingly, pDC depletion by 120G8 mAb administration was seen to promote plaque T cell accumulation and exacerbate lesion development and progression in LDLr−/− mice. PDC depletion was accompanied by increased CD4+ T cell proliferation, IFN-γ expression by splenic T cells and plasma IFN-γ levels. Lymphoid tissue pDC from atherosclerotic mice showed increased indoleamine 2,3-dioxygenase (IDO) expression and IDO blockage abrogated the pDC suppressive effect on T cell proliferation.
Our data reveal a protective role for pDC in atherosclerosis, possibly by dampening T cell proliferation and activity in peripheral lymphoid tissue, rendering pDC an interesting target for future therapeutic interventions.
Plasmacytoid dendritic cells; atherosclerosis; immune tolerance; T cells
The pathophysiological hallmark of spotted fever group rickettsioses comprises vascular inflammation. Based on the emerging importance of the wingless (Wnt) pathways in inflammation and vascular biology, we hypothesized that Dickkopf-1 (DKK-1), as a major modulator of Wnt signaling, could be involved in the pathogenesis in rickettsial infections. Our major findings were: (i) While baseline concentration of DKK-1 in patients with R. conorii infection (n = 32) were not different from levels in controls (n = 24), DKK-1 rose significantly from presentation to first follow-up sample (median 7 days after baseline). (ii) In vitro experiments in human umbilical vein endothelial cells (HUVECs) showed that while heat-inactivated R. conorii enhanced the release of interleukin-6 (IL-6) and IL-8, it down-regulated the release of endothelial-derived DKK-1 in a time- and dose-dependent manner. (iii) Silencing of DKK-1 attenuated the release of IL-6, IL-8 and growth-related oncogene (GRO)α in R. conorii-exposed HUVECs, suggesting inflammatory effects of DKK-1. (iv) Silencing of DKK-1 attenuated the expression of tissue factor and enhanced the expression of thrombomodulin in R. conorii-exposed HUVECs suggesting pro-thrombotic effects of DKK-1. The capacity of R. conorii to down-regulate endothelial-derived DKK-1 and the ability of silencing DKK-1 to attenuate R. conorii-induced inflammation in endothelial cells could potentially reflect a novel mechanism by which R. conorii escapes the immune response at the site of infection.
In addition to lowering cholesterol, statins are thought to beneficially modulate inflammation. Several chemokines including CXCL1/growth-related oncogene (GRO)-α, CXCL8/interleukin (IL)-8 and CCL2/monocyte chemoattractant protein (MCP)-1 are important in the pathogenesis of atherosclerosis and can be influenced by statin-treatment. Recently, we observed that atorvastatintreatment alters the intracellular content and subcellular distribution of GRO-α in cultured human umbilical vein endothelial cells (HUVECs). The objective of this study was to investigate the mechanisms involved in this phenomenon.
Methodology/ Principal Findings
The effect of atorvastatin on secretion levels and subcellular distribution of GRO-α, IL-8 and MCP-1 in HUVECs activated by interleukin (IL)-1β were evaluated by ELISA, confocal microscopy and immunoelectron microscopy. Atorvastatin increased the intracellular contents of GRO-α, IL-8, and MCP-1 and induced colocalization with E-selectin in multivesicular bodies. This effect was prevented by adding the isoprenylation substrate GGPP, but not the cholesterol precursor squalene, indicating that atorvastatin exerts these effects by inhibiting isoprenylation rather than depleting the cells of cholesterol.
Atorvastatin targets inflammatory chemokines to the endocytic pathway and multivesicular bodies and may contribute to explain the anti-inflammatory effect of statins at the level of endothelial cell function.
On the basis of the role of activin A in inflammation, atherogenesis, and glucose homeostasis, we investigated whether activin A could be related to glucometabolic abnormalities in patients with acute myocardial infarction (MI).
RESEARCH DESIGN AND METHODS
Activin A measurement and oral glucose tolerance tests (OGTTs) were performed in patients (n = 115) with acute MI, without previously known diabetes, and repeated after 3 months. Release of activin A and potential anti-inflammatory effects of activin A were measured in human endothelial cells. Activin A effects on insulin secretion and inflammation were tested in human pancreatic islet cells.
1) In patients with acute MI, serum levels of activin A were significantly higher in those with abnormal glucose regulation (AGR) compared with those with normal glucose regulation. Activin A levels were associated with the presence of AGR 3 months later (adjusted odds ratio 5.1 [95% CI 1.73–15.17], P = 0.003). 2) In endothelial cells, glucose enhanced the release of activin A, whereas activin A attenuated the release of interleukin (IL)-8 and enhanced the mRNA levels of the antioxidant metallothionein. 3) In islet cells, activin A attenuated the suppressive effect of inflammatory cytokines on insulin release, counteracted the ability of these inflammatory cytokines to induce mRNA expression of IL-8, and induced the expression of transforming growth factor-β.
We found a significant association between activin A and newly detected AGR in patients with acute MI. Our in vitro findings suggest that this association represents a counteracting mechanism to protect against inflammation, hyperglycemia, and oxidative stress.
Dietary fat is normally in TAG form, but diacylglycerol (DAG) is a natural component of
edible oils. Studies have shown that consumption of DAG results in metabolic
characteristics that are distinct from those of TAG, which may be beneficial in preventing
and managing obesity. The objective of the present study was to investigate if food items
in which part of the TAG oil is replaced with DAG oil combined with high α-linolenic acid
(ALA) content would influence metabolic markers. A 12-week double-blinded randomised
controlled parallel-design study was conducted. The participants (n 23)
were healthy, overweight men and women, aged 37–67 years, BMI 27–35 kg/m2, with
waist circumference >94 cm (men) and >88 cm (women). The two groups received
20 g margarine, 11 g mayonnaise and 12 g oil per d, containing either high ALA and
sn-1,3-DAG or high ALA and TAG. Substitution of TAG oil with DAG oil in
food items for 12 weeks led to an improvement of the predicted 10 years cardiovascular
risk score in overweight subjects by non-significantly improving markers of health such as
total body fat percentage, trunk fat mass, alanine aminotransferase, systolic blood
pressure, γ-glutamyl transferase, alkaline phosphatase and total fat-free mass. This may
suggest that replacing TAG oil with DAG oil in healthy, overweight individuals may have
beneficial metabolic effects.
Diacylglycerol; TAG; Overweight human subjects; Liver markers; ALA, α-linolenic acid; ALAT, alanine aminotransferase; ALP, alkaline phosphatase; ASAT, aspartame aminotransferase; CRP, C-reactive protein; DAG, diacylglycerol; FFM, fat-free mass; γ-GT, γ-glutamyl transferase; HOMA-IR, homeostatic model assessment for insulin resistance; hsCRP, high-sensitivity CRP
Background and Purpose
Fatty acid binding protein 4 (FABP4) has been shown to play an important role in macrophage cholesterol trafficking and associated inflammation. To further elucidate the role of FABP4 in atherogenesis in humans, we examined the regulation of FABP4 in carotid atherosclerosis and ischemic stroke.
We examined plasma FABP4 levels in asymptomatic (n = 28) and symptomatic (n = 31) patients with carotid atherosclerosis, as well as in 202 subjects with acute ischemic stroke. In a subgroup of patients we also analysed the expression of FABP4 within the atherosclerotic lesion. In addition, we investigated the ability of different stimuli with relevance to atherosclerosis to regulate FABP4 expression in monocytes/macrophages.
FABP4 levels were higher in patients with carotid atherosclerosis, both systemically and within the atherosclerotic lesion, with particular high mRNA levels in carotid plaques from patients with the most recent symptoms. Immunostaining of carotid plaques localized FABP4 to macrophages, while activated platelets and oxidized LDL were potent stimuli for FABP4 expression in monocytes/macrophages in vitro. When measured at the time of acute ischemic stroke, high plasma levels of FABP4 were significantly associated with total and cardiovascular mortality during follow-up, although we did not find that addition of FABP4 to the fully adjusted multivariate model had an effect on the prognostic discrimination for all-cause mortality as assessed by c-statistics.
FABP4 is linked to atherogenesis, plaque instability and adverse outcome in patients with carotid atherosclerosis and acute ischemic stroke.
There is convincing evidence that replacing dietary saturated fats with polyunsaturated fats (PUFA) decreases risk of cardiovascular diseases. Therefore, PUFA rich foods such as vegetable oils, fatty fish, and marine omega-3 supplements are recommended. However, PUFA are easily oxidizable and there is concern about possible negative health effects from intake of oxidized lipids. Little is known about the degree of lipid oxidation in such products.
To assess the content of lipid oxidation products in a large selection of vegetable oils and marine omega-3 supplements available in Norway. Both fresh and heated vegetable oils were studied.
A large selection of commercially available vegetable oils and marine omega-3 supplements was purchased from grocery stores, pharmacies, and health food stores in Norway. The content of lipid oxidation products were measured as peroxide value and alkenal concentration. Twelve different vegetable oils were heated for a temperature (225°C) and time (25 minutes) resembling conditions typically used during cooking.
The peroxide values were in the range 1.04–10.38 meq/kg for omega-3 supplements and in the range 0.60–5.33 meq/kg for fresh vegetable oils. The concentration range of alkenals was 158.23–932.19 nmol/mL for omega-3 supplements and 33.24–119.04 nmol/mL for vegetable oils. After heating, a 2.9–11.2 fold increase in alkenal concentration was observed for vegetable oils.
The contents of hydroperoxides and alkenals in omega-3 supplements are higher than in vegetable oils. After heating vegetable oils, a large increase in alkenal concentration was observed.
lipid oxidation; commercially available; vegetable oils; marine omega-3 supplements; screening; peroxide value; alkenal concentration
Inflammatory mechanisms have been suggested to play a role in the development
of heart failure (HF), but a role for chemokines is largely unknown. Based
on their role in inflammation and matrix remodeling in other tissues, we
hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling
We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5
in cardiac pathophysiology leading to HF.
Methods and Results
Mice harboring a systemic knockout of the CXCR5
(CXCR5−/−) displayed increased mortality during a
follow-up of 80 days after aortic banding (AB). Following three weeks of AB,
CXCR5−/− developed significant left ventricular
(LV) dilatation compared to wild type (WT) mice. Microarray analysis
revealed altered expression of several small leucine-rich proteoglycans
(SLRPs) that bind to collagen and modulate fibril assembly. Protein levels
of fibromodulin, decorin and lumican (all SLRPs) were significantly reduced
in AB CXCR5−/− compared to AB WT mice. Electron
microscopy revealed loosely packed extracellular matrix with individual
collagen fibers and small networks of proteoglycans in AB
CXCR5−/− mice. Addition of CXCL13 to cultured
cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF,
we observed increased myocardial levels of CXCR5 and SLRPs, which was
reversed following LV assist device treatment.
Lack of CXCR5 leads to LV dilatation and increased mortality during pressure
overload, possibly via lack of an increase in SLRPs. This study demonstrates
a critical role of the chemokine CXCL13 and CXCR5 in survival and
maintaining of cardiac structure upon pressure overload, by regulating
proteoglycans essential for correct collagen assembly.
The aim of the present paper was to review the literature in order to summarize the effects of marine n-3 fatty acids on circulating inflammatory markers among healthy subjects, subjects with high risk of developing cardiovascular disease (CVD) and in patients with CVD in human intervention studies.
A systematic literature search in PubMed was performed. Intervention studies describing the effects of marine n-3 fatty acids on circulating inflammatory markers in healthy subjects, subjects with high risk of CVD and patients with CVD were included. The following exclusion criteria were used: (1) interventions assessing inflammatory markers with ex vivo methods (2) interventions with children (3) articles describing animal or cell culture studies. Twenty-two articles were included. Additionally, 13 papers from their literature lists were included based on the same inclusion and exclusion criteria as the literature search.
Results and conclusion
Intervention studies with marine n-3 fatty acids administered from either fish or fish oil demonstrate different results on inflammatory markers. No firm conclusion can be drawn about the effect of marine n-3 fatty acids on circulating inflammatory markers in healthy individuals, individuals with high risk of developing CVD or individuals with CVD related diseases.
Omega-3 fatty acids; Atherosclerosis; Inflammation; Circulating inflammatory markers; PBMCs
The liver X receptors (LXR) α and β regulate lipid and carbohydrate homeostasis and inflammation. Lxrβ-/- mice are glucose intolerant and at the same time lean. We aimed to assess the associations between single nucleotide polymorphisms (SNPs) in LXRβ and risk of type 2 diabetes mellitus (T2DM), obesity and related traits in 3 separate cohort studies.
Twenty LXRβ SNPs were identified by sequencing and genotyped in the HUNT2 adult nested case-control study for T2DM (n = 835 cases/1986 controls). Five tag-SNPs (rs17373080, rs2695121, rs56151148, rs2303044 and rs3219281), covering 99.3% of the entire common genetic variability of the LXRβ gene were identified and genotyped in the French MONICA adult study (n = 2318) and the European adolescent HELENA cross-sectional study (n = 1144). In silico and in vitro functionality studies were performed.
We identified suggestive or significant associations between rs17373080 and the risk of (i) T2DM in HUNT2 (OR = 0.82, p = 0.03), (ii) obesity in MONICA (OR = 1.26, p = 0.05) and (iii) overweight/obesity in HELENA (OR = 1.59, p = 0.002). An intron 4 SNP (rs28514894, a perfect proxy for rs17373080) could potentially create binding sites for hepatic nuclear factor 4 alpha (HNF4α) and nuclear factor 1 (NF1). The C allele of rs28514894 was associated with ~1.25-fold higher human LXRβ basal promoter activity in vitro. However, no differences between alleles in terms of DNA binding and reporter gene transactivation by HNF4α or NF1 were observed.
Our results suggest that rs17373080 in LXRβ is associated with T2DM and obesity, maybe via altered LXRβ expression.
Aspergillus fumigatus is the most frequent cause of invasive mold infections worldwide. Platelets contribute to inflammation and promote thrombosis, characteristically seen in aspergillosis, and might be involved both in antifungal defense and in the histopathological process. In the experiments reported here, in vitro activation of platelets by conidia, swollen conidia, and hyphae from A. fumigatus was assessed by flow cytometry and enzyme immunoassays. THP-1 monocytes and human monocytes with and without platelets were cultured with hyphae from A. fumigatus, and the release of interleukin-8 (IL-8) was measured by enzyme immunoassays. A. fumigatus potently induced the expression of CD62-p and CD63 and the release of CD40 ligand, RANTES, and Dickkopf homolog 1 in platelets, with particularly enhancing effects of hyphae compared with conidia. The hypha-mediated activation of platelets further enhanced the release of IL-8 both in THP-1 monocytes and in human adherent monocytes. In conclusion, we have found that A. fumigatus is a potent inducer of platelet-mediated inflammation, potentially promoting protective as well as harmful responses during aspergillosis.
A plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies.
We procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table.
The results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values.
This database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet.