Abstract 175: Activation of Nrf2 by Exercise Training and Curcumin Contributes to Sympatho-Inhibition in Heart Failure

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Abstract

Chronic Heart Failure (CHF) is a disease characterized by increased Angiotensin II type 1 receptor (AT1R) signaling, sympathetic outflow, and oxidative stress. In conditions of high oxidant stress, Nuclear factor erythroid 2 related factor 2 (Nrf2) is dissociated from Kelch-like ECH associated protein 1 (Keap1) to activate antioxidant response element (ARE)genes. Nuclear factor kappa B (NF-kB) is a transcription factor downstream of AT1R that inhibits ARE transcription . Exercise training (ExT) decreases sympathetic outflow and oxidative stress, but the mechanism(s) by which ExT is protective remain unclear. The aim of this study was to investigate if ExT indirectly activates Nrf2 and if direct Nrf2 activation by curcumin (Cur) in rats with CHF would decrease sympatho-excitation and normalize AT1R pathway overactivation. Rats were ExT for 4 weeks post-surgery on a treadmill at a final speed of 25 m/min for 60 minutes, 5 days a week for 6 weeks. Western blot analyses of RVLM micropunches are summarized in the Table. Briefly, in CHF, there was a significant upregulation in NF-kB and Keap1 and a decrease in Nrf2 protein compared to sham. ExT significantly increased Nrf2 expression compared to both sham and CHF groups but normalized NF-kB and AT1R expression in CHF animals. Oral Cur (200mg/kg/day) decreased resting HR, urinary norepinephrine excretion, and renal sympathetic nerve activity in CHF animals. Western blot analyses indicated that Cur increased Nrf2, decreased NF-kB and normalized AT1R expression in the RVLM (Table). Taken together, Nrf2 activation may be protective in normalizing AT1R expression in CHF and one of the mechanisms by which ExT exerts its beneficial effects.

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