Differential effects of fatty acids on the endothelium

Background: Endothelial dysfunction is a major factor in the development of atherosclerosis, thrombosis and heart disease. Evidence suggests dietary fat composition may modify cardiovascular risk, as well as surrogate markers of cardiovascular risk such as blood pressure, arterial stiffness and endothelium-dependent vasodilation. Aim: To investigate the impact of dietary fat composition on endothelial function and associated markers of vascular health. Methods: The effects of oils rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were separately investigated in a parallel-design, placebo-controlled randomised controlled trial (n=48, 6 weeks, 2.9 g/d), carried out in free-living healthy young men. Following a 2 week run-in period taking placebo capsules (olive oil), participants underwent baseline measurements of finger capillary density, endothelial progenitor cell numbers (EPC), platelet-monocyte aggregate numbers (PMA), ambulatory blood pressure (ABP), pulse wave analysis (PWA), digital volume pulse analysis (DVP), and gave blood samples for plasma lipid, glucose, insulin, nitric oxide metabolites (NOx) and isoprostanes. The same measurements were made at the study endpoint, 6 weeks. An in vitro investigation of the effects of physiologically-relevant fatty acid profiles on microvascular endothelial cell nitric oxide and prostacyclin production was also performed. Results: Neither EPA nor DHA supplementation influenced EPCs, capillary density, PMA, ABP, PWA, DVP or plasma cholesterol, triacylglycerol, glucose, insulin, NOx or isoprostanes compared to placebo. However, ambulatory night-time heart rate was increased following EPA supplementation compared to DHA. Furthermore, both EPA and DHA decreased plasma non-esterified fatty acids (NEFA) compared to placebo. The in vitro investigations suggested that the composition of circulating NEFA may differentially affect endothelial function in the microvasculature. Conclusion: Dietary EPA and DHA at relatively high doses do not improve a number of novel markers of vascular function, including microvascular function and a marker of endothelial repair in young healthy men. EPA and DHA have differing effects on heart rate during sleep, suggesting that further research is required into the possible adverse effects of higher doses of individual marine fatty acids in at-risk individuals. Further work is required to elucidate the role of physiological fatty acid profiles on endothelial function.

Name dc:type.qualificationname

Doctor of Philosophy

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

King's College London

Year dc:date.issued

2012

Author dc:creator

• Cottin, Sarah

Advisors dc:contributor.advisor

• Hall, Wendy Louise
• Sanders, Thomas

• Fatty acids
• Endothelium
• Cardiovascular disease
• n-3 PUFA

Language dc:language

eng

Identifier

oai:kclpure.kcl.ac.uk:studenttheses/8655cd9b-072c-4365-928c-2ab28549ad78

OAI identifier oai:identifier

oai:kclpure.kcl.ac.uk:studenttheses/8655cd9b-072c-4365-928c-2ab28549ad78