Introduction/purpose: Inflammation contributes to heart failure (HF) progression and the interleukin (IL)-1 cytokine IL-1β is implicated in this process. The adaptor protein apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is necessary for inflammasome activation of IL-1β. Lower ASC methylation is associated with worse outcomes in HF. The purpose of this study was to examine the effects of exercise on changes in ASC methylation and activation of the IL-1 family cytokine IL-1β in persons with HF.
Methods: Participants (N = 54) were randomized to receive exercise intervention (n = 38) or attention control (n = 16) for 3 months. Percent methylation of the ASC gene, plasma IL-1β, and ASC mRNA and were obtained at baseline, 3 months, and 6 months.
Results: ASC methylation was higher in the exercise group as compared to control at 3 months (6.10% ± 0.5% vs 5.80% ± 0.4%; P = 0.04) and 6 months (6.07 ± 0.4 vs 5.82 ± 0.4; P = 0.04). Plasma IL-1β was lower in the exercise group at 3 months (1.43 ± 0.5 pg·mL vs 2.09 ± 1.3 pg·mL; P = 0.02) and 6 months (1.49 ± 0.5 pg·mL vs 2.13 ± 1.4 pg·mL; P = 0.004). ASC mRNA expression was negatively associated with ASC methylation at baseline (r = -0.97, P = 0.001), 3 months (r = -0.90, P = 0.001), and 6 months (r = -0.81, P = 0.001). ASC mRNA was lower than baseline at 3 months (P = 0.004) and 6 months (P = 0.002) among those in the exercise group. ASC methylation was positively associated with 6-min walk test at baseline (r = 0.517, P < 0.001), 3 months (r = 0.464, P = 0.004), and 6 months (r = 497, P = 0.05).
Conclusions: Exercise was related to increased mean percent ASC methylation and decreased IL-1β and ASC mRNA gene expression in HF. Epigenetic regulation of ASC can be a biological mechanism by which exercise can promote better outcomes in HF.