ENabling Reduction of Low-grade Inflammation in SEniors Pilot Study: Concept, Rationale, and Design

Abstract

Objectives: To test two interventions to reduce interleukin (IL)-6 levels, an indicator of low-grade chronic inflammation and an independent risk factor for impaired mobility and slow walking speed in older adults.

Design: The ENabling Reduction of low-Grade Inflammation in SEniors (ENRGISE) Pilot Study was a multicenter, double-blind, placebo-controlled randomized pilot trial of two interventions to reduce IL-6 levels.

Setting: Five university-based research centers.

Participants: Target enrollment was 300 men and women aged 70 and older with an average plasma IL-6 level between 2.5 and 30 pg/mL measured twice at least 1 week apart. Participants had low to moderate physical function, defined as self-reported difficulty walking one-quarter of a mile or climbing a flight of stairs and usual walk speed of less than 1 m/s on a 4-m usual-pace walk.

Intervention: Participants were randomized to losartan, omega-3 fish oil (ω-3), combined losartan and ω-3, or placebo. Randomization was stratified depending on eligibility for each group. A titration schedule was implemented to reach a dose that was safe and effective for IL-6 reduction. Maximal doses were 100 mg/d for losartan and 2.8 g/d for ω-3.

Measurements: IL-6, walking speed over 400 m, physical function (Short Physical Performance Battery), other inflammatory markers, safety, tolerability, frailty domains, and maximal leg strength were measured.

Results: Results from the ENRGISE Pilot Study will provide recruitment yields, feasibility, medication tolerance and adherence, and preliminary data to help justify a sample size for a more definitive randomized trial.

Conclusion: The ENRGISE Pilot Study will inform a larger subsequent trial that is expected to have important clinical and public health implications for the growing population of older adults with low-grade chronic inflammation and mobility limitations.

Keywords: chronic inflammation; immune system; mobility disability; physical function.

Figure

Illustration of selected mechanisms potentially leading to progressive mobility disability that may be amenable to intervention using anti-inflammatory inventions being proposed by the ENRGISE Pilot study. The three main sources of inflammation in elders (genetic and epi genetic factors, exogenous factors and endogenous factors) combine to cause molecular and biochemical changes with important consequences, which in turn lead to physiological consequences and ultimately to mobility limitation and mortality.