Effects of n3 LC PUFAs on Inflammatory, Immune and Senescence Features in Polyvascular Older Subjects (OMSAGE)

Medical Background

Declines in immune function with age and an imbalance between pro- and anti-inflammatory mechanisms lead to a high incidence of infectious and cardiovascular disease among older individuals. ω-3 polyunsaturated fatty acids (EPA and DHA) are anti-inflammatory and represent a substrate of potent mediators, termed specialized proresolving mediators (SPMs). Specialized proresolving mediators (SPMs) are known to limit excessive neutrophil and monocyte migration and stimulate the uptake of apoptotic neutrophils and microbes, thus promoting the resolution of inflammation. Increases in SPM concentrations are linked with decreased uptake of oxidized low-density lipoproteins . Phagocyte functional decline with senescence has been well established. Aged macrophages exhibit functional changes such as compromised chemotaxis, impaired ability to phagocytose pathogenic bacteria, reduced expression of MHC class II molecules and decreased capacity for antigen presentation. However, how phagocyte dysfunction changes with the acquisition of a senescence phenotype is currently unknown.

Some components, such as polyunsaturated fatty acids (n-3 PUFAs), also prevent the induction of senescence and atherosclerosis but also have extensive immunomodulatory effects. The supplementation of fish oil (4 g n-3 PUFA/d) for 3 weeks in healthy older subjects induced dynamic reshaping of human CD4+ T cells and plasma membrane organization. Additionally, 5 days of n-3 PUFA supplementation was associated with an increase in the phagocytic activity of peripheral blood monocytes and neutrophils. The utility of n-3 PUFA-enriched supplements in the prevention of cardiovascular disease has been highlighted. Recently, the EVAPORATE study revealed that the combination of icosapentethyl, a highly purified form of eicopentaenoic acid ethyl ester, and statins might increase the regression of low-attenuation plaque volume on multidetector computed tomography compared with a placebo over 18 months. Specialized proresolving mediators (SPMs), bioactive lipids derived from n-3 PUFAs and leading to the resolution of inflammation, seem to be potential biomarkers for determining the immune regulatory potential of n-3 PUFAs. While native and mox LDL induce the release of inflammatory cytokines and mediators derived from docosahexaenoic acid (DHA) resolvin D1 from young endothelial cells, the effect of mox-LDL in senescent cells on SPM production is unknown. Eicosapentaenoic acid (EPA) and DHA significantly reduce H2O2-induced senescence-associated β-galactosidase activity in cells (by 31% and 22%, respectively). The consumption of fish oil, the main source of n-3 PUFAs, increases phagocytosis and the population of CD4+ and CD8+ lymphocytes in forty-five older healthy Caucasian women.

Drug profile

The substances evaluated will be polyunsaturated fatty acids such as eicosapentaenoic acid (EPA or C20: 5ω-3) and docosahexaenoic acid (DHA or C22: 6 ω-3).

EPA and DHA are known for their anti-inflammatory effects through the inhibition of NFkB pathway activation, the decrease in lipid raft formation, entry into competition with arachidonic acid and the formation of lower-intensity eicosanoids and leukotrienes. They are also known to generate proresolutive mediators called SPMs, such as resolvins, protectins, and maresins. Although their effects are anti-inflammatory and proresolutive, they do not present immunosuppressive effects. The impact of these molecules on different endpoints and on different populations seems less obvious. People with vascular disease may be more sensitive to the effects of these molecules.

Rationale

Study population - dose-duration-administration schedule and hypothesis

Omega-3 fatty acids are important structural components of cell membranes and contribute to various membrane functions, such as fluidity, permeability, the activity of membrane-bound enzymes and receptors, and signal transduction. In 2006, Rees et al reported that 60-year-old subjects were more sensitive to the immunologic effects of EPA and that the neutrophil respiratory burst was lower in those with EPA intake greater than 2,7 g/day. Additionally, the most notable cellular and biochemical changes reported in a study conducted by Schaller et al. occurred in 70-year-old patients with peripheral artery disease. Supplementation for 5 days led to an increase in the phagocytic activity of peripheral blood monocytes and neutrophils. Immunonutrition containing more than 2 g/day of omega-3 has shown encouraging preventive effects against infectious postoperative complications among 65-year-old subjects. The duration of drug administration was only 5 consecutive days. The investiguators hypothesize that a dose of ± 2 g per day for 7 days among older subjects with vascular disease will be sufficient to affect monocyte function (macrophage polarisation) and lymphocyte function after 21 days. The investiguators also propose that a combination of DHA at a lower dose combined with EPA will have the same or a better effect on immune parameters than EPA or DHA alone. A eventual"residual effect" observed 30 days after the last administration will be measured.

The investiguators suggest that of atherosclerotic lesions in older individuals induce high-level secretory components, known as the senescence-associated secretory phenotype (SASP), and induce insufficient proresolutive responses in peripheral blood mononuclear cells, which can be reversed by EPA and DHA in different ways. The investiguators aimed to observe the effects of LC n-3 PUFAs on immune cells through improvements in inflammatory and senescence markers.

Design

This monocentric study is an interventional experimental plan to understand physiopathological processes in older subjects. This randomized, controlled, double-blind, 2x2 factorial trial will be performed in polyvascular subjects over 75 years of age, without direct individual benefit.

A total of 80 participants (20 participants in each arm) were divided into 4 groups. One group will receive ± 2,4 g/day of DHA, a second will receive ± 2,4 g/d of EPA, and a third group will receive a combination of DHA and EPA. The control group will receive a placebo.

To respect the blindness procedure (double-blind), the total number of capsules to be taken by the patient per day will be 2 capsules in the morning and 2 capsules in the evening for 21 days. On the first day and in the morning, the subject took all 4 capsules at one time.

Biological parameters will be measured prospectively from blood samples taken at different times. Each subject will end his participation on the 51st day, the day of the last visit, with a blood test.

Block randomization will be performed and stratified by sex.