Differential Effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) on Platelet, Endothelial and Vascular Function
|Healthy||Dietary Supplement: EPA-rich triacylglycerol oil Dietary Supplement: Placebo - olive oil (BP specification) Dietary Supplement: DHA-rich triacylglycerol oil|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Prevention
|Official Title:||Investigation Into Incorporation of (n-3) Polyunsaturated Fatty Acids Into Erythrocyte Membranes and Clearance, and Effects on Platelet Function, Arterial Function and Endothelial Repair|
- Platelet Monocyte Aggregates (PMA) [ Time Frame: 6 weeks ]The endothelium plays a vital role in the regulation of blood flow, thrombosis and inflammation. Endothelium-derived anti-adhesive and anti-aggregant substances, including prostacyclin and nitric oxide, are known to inhibit platelet activation. Endothelial dysfunction or vessel wall injury lead to the activation of platelets, of which platelet-monocyte-aggregates (PMA) are a sensitive marker, and were shown to inversely correlate with markers of EF in patients with stable CHD. The measurement of PMA by flow cytometry is a method which reduces ex vivo platelet activation to its minimum and is believed to represent platelet activation in vivo.
- Endothelial Progenitor Cell (EPC) counts [ Time Frame: 6 weeks ]EPCs are a subgroup of circulating progenitor cells that are recruited from the bone marrow to repair the injured vasculature. They have been associated with a reduced CVD risk and may serve as markers of endothelial function because they represent a greater capacity for the endothelium to repair itself. Two populations of EPCs were measured by flow cytometry, described as 'early EPC' (KDR+/CD34+/CD133+) and 'late EPCs' (KDR+/CD34+/CD31+).
- Capillary density [ Time Frame: 6 weeks ]Capillary rarefaction has been associated to CVD risk factors such as hypertension, smoking and obesity. The cutaneous circulation has emerged as an accessible and representative vascular bed to look at microvascular dysfunction. Capillary density was measured by a Capiscope (kk technologies)
- Arterial stiffness [ Time Frame: 6 weeks ]Pulse wave analysis (PWA) was used to measure indices of arterial stiffness, including peripheral and central augmentation index, as well as central systolic and diastolic blood pressure. Digital volume pulse (DVP) was used to measure reflection and stiffness indices.
- Blood Pressure (BP) and Heart Rate (HR) [ Time Frame: 6 weeks ]Resting HR and BP were measured in the seated and supine position after 15 minute rest, on the days of both baseline and endpoint visits. In addition, ambulatory BP and HR (24h, daytime, nighttime) was measured 2-3 days prior to each visit.
- Plasma isoprostane concentrations [ Time Frame: 6 weeks ]8-iso-prostaglandin-F2α (8-IsoP-F2α), a prostaglandin F2-like compound biosynthesized nonenzymatically by a free-radical oxygenation of arachidonic acid, was measured in plasma in order to assess oxidative stress.
- Plasma Nitrate and Nitrites (NOx) concentrations [ Time Frame: 6 weeks ]Plasma NOx was measured as a circulating marker of endothelial function.
- Serum total cholesterol concentration [ Time Frame: 6 weeks ]
- Serum Triacylglycerol concentrations [ Time Frame: 6 weeks ]
- Serum high density lipoprotein concentration [ Time Frame: 6 weeks ]
- Serum low density lipoprotein concentration [ Time Frame: 6 weeks ]
- Serum non esterified fatty acids (NEFA) concentration [ Time Frame: 6 weeks ]
- Serum Apolipoprotein B concentration [ Time Frame: 6 weeks ]
- Plasma glucose concentration [ Time Frame: 6 weeks ]
- Plasma insulin concentration [ Time Frame: 6 weeks ]
- Serum adiponectin concentration [ Time Frame: 6 weeks ]
- Serum resistin concentration [ Time Frame: 6 weeks ]
- Erythrocyte phospholipid fatty acid profiles [ Time Frame: 6 weeks ]The EPA and DHA content of erythrocyte lipids were used as a marker of compliance.
- Fatty acid profile of plasma non esterified fatty acid fraction [ Time Frame: 6 weeks ]
|Study Start Date:||June 2009|
|Study Completion Date:||April 2010|
|Primary Completion Date:||April 2010 (Final data collection date for primary outcome measure)|
Placebo Comparator: Olive oil (BP specification)
5g per day
|Dietary Supplement: Placebo - olive oil (BP specification)|
Experimental: DHA-rich oil
Fish oil supplement (total = 5g/day) providing 3.1g/day of DHA triacylglycerol, blended with olive oil
|Dietary Supplement: DHA-rich triacylglycerol oil|
Experimental: EPA-rich oil
Fish oil supplement (total = 5g/day) providing 2.9g/day of EPA triacylglycerol, blended with olive oil
|Dietary Supplement: EPA-rich triacylglycerol oil|
Relatively few studies have made a head-to-head comparison of DHA (22:6n-3) with EPA (20:5n-3). The understanding of this differential effect may be of great interest in populations with low EPA intake such as vegetarians, who may choose to supplement their dietary intake of long-chain n-3 PUFA in the form of DHA-rich algal oil.
This study aimed to investigate the effect of supplementation with oils rich in either EPA or DHA (3g/day, 6 weeks) in healthy young males on platelet, endothelial and vascular function, as well as other CVD risk factors. The primary outcomes were platelet monocyte aggregates and endothelial progenitor cells - novel markers of platelet and endothelial function, measured by flow cytometry, Secondary outcomes included capillary density, measured by capillaroscopy to assess changes in microvascular function, pulse wave analysis, digital volume pulse and ambulatory blood pressure. Other secondary outcomes included lipid profiles (TAG, cholesterol, NEFA), glycaemic control (HOMA, QUICKI) and oxidative stress (isoprostane). The omega-3 index (erythrocyte EPA+DHA) was used as a marker of compliance.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01735357
|Diabetes & Nutritional Sciences Division, King's College London|
|London, United Kingdom, SE1 9NH|
|Principal Investigator:||Wendy L Hall, PhD||King's College London|