ABSTRACT
OBJECTIVE: Plant-derived α-linolenic acid (ALA) may constitute an attractive cardioprotective alternative to fish-derived n-3 fatty acids. However, the effect of dietary ALA on arterial thrombus formation remains unknown. METHODS AND RESULTS: Male C57Bl/6 mice were fed a high-ALA or low-ALA diet for 2 weeks. Arterial thrombus formation was delayed in mice fed a high-ALA diet compared with those on a low-ALA diet (n=7; P<0.005). Dietary ALA impaired platelet aggregation to collagen and thrombin (n=5; P<0.005) and decreased p38 mitogen-activated protein kinase activation in platelets. Dietary ALA impaired arterial tissue factor (TF) expression, TF activity, and nuclear factor-κB activity (n=7; P<0.05); plasma clotting times and plasma thrombin generation did not differ (n=5; P=not significant). In cultured human vascular smooth muscle and endothelial cells, ALA inhibited TF expression and activity (n=4; P<0.01). Inhibition of TF expression occurred at the transcriptional level via the mitogen-activated protein kinase p38 in smooth muscle cells and p38, extracellular signal-regulated kinases 1 and 2, and c-Jun N-terminal kinases 1 and 2 in endothelial cells. CONCLUSIONS: ALA impairs arterial thrombus formation, TF expression, and platelet activation and thereby represents an attractive nutritional intervention with direct dual antithrombotic effects.
Subject(s)
Cardiotonic Agents/administration & dosage , Carotid Artery Thrombosis/prevention & control , Platelet Activation/drug effects , Thromboplastin/metabolism , alpha-Linolenic Acid/administration & dosage , Animals , Carotid Arteries/drug effects , Carotid Arteries/metabolism , Carotid Artery Thrombosis/blood , Carotid Artery Thrombosis/metabolism , Cells, Cultured , Dietary Supplements , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Gene Expression/drug effects , Humans , MAP Kinase Kinase Kinase 5/metabolism , MAP Kinase Signaling System/drug effects , Male , Mice , Mice, Inbred C57BL , Myocytes, Smooth Muscle/drug effects , Myocytes, Smooth Muscle/metabolism , NF-kappa B/metabolism , Platelet Aggregation/drug effects , Thromboplastin/genetics , Tumor Necrosis Factor-alpha/pharmacology , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
AIMS: Epidemiological studies report an inverse association between plant-derived dietary α-linolenic acid (ALA) and cardiovascular events. However, little is known about the mechanism of this protection. We assessed the cellular and molecular mechanisms of dietary ALA (flaxseed) on atherosclerosis in a mouse model. METHODS AND RESULTS: Eight-week-old male apolipoprotein E knockout (ApoE(-/-)) mice were fed a 0.21 % (w/w) cholesterol diet for 16 weeks containing either a high ALA [7.3 % (w/w); n = 10] or low ALA content [0.03 % (w/w); n = 10]. Bioavailability, chain elongation, and fatty acid metabolism were measured by gas chromatography of tissue lysates and urine. Plaques were assessed using immunohistochemistry. T cell proliferation was investigated in primary murine CD3-positive lymphocytes. T cell differentiation and activation was assessed by expression analyses of interferon-γ, interleukin-4, and tumour necrosis factor α (TNFα) using quantitative PCR and ELISA. Dietary ALA increased aortic tissue levels of ALA as well as of the n-3 long chain fatty acids (LC n-3 FA) eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. The high ALA diet reduced plaque area by 50% and decreased plaque T cell content as well as expression of vascular cell adhesion molecule-1 and TNFα. Both dietary ALA and direct ALA exposure restricted T cell proliferation, differentiation, and inflammatory activity. Dietary ALA shifted prostaglandin and isoprostane formation towards 3-series compounds, potentially contributing to the atheroprotective effects of ALA. CONCLUSION: Dietary ALA diminishes experimental atherogenesis and restricts T cell-driven inflammation, thus providing the proof-of-principle that plant-derived ALA may provide a valuable alternative to marine LC n-3 FA.
