Despite
standard drug therapy, sympathetic nerve activity (SNA) remains high in heart
failure (HF) patients making the sympathetic nervous system a primary drug
target in the treatment of HF. Studies in rabbits with pacing-induced HF have
demonstrated that statins reduce resting SNA, in part, due to reductions in
reactive oxygen species (ROS). Whether these findings can be extended to the
clinical setting of human HF remains unclear. We first performed a study in
seven statin-naïve HF patients (56±2 yrs; ejection fraction 31±4%) to determine
if one month of Simvastatin (40 mg/day) reduces muscle SNA (MSNA). Next, to
control for possible placebo effects and determine the effect of Simvastatin on
ROS, a double-blinded, placebo-controlled crossover design study was performed
in six additional HF patients (51±3 yrs; ejection fraction 22±4%) and MSNA, and
ROS and superoxide were measured. We tested the hypothesis that statin therapy
decreases resting MSNA in HF patients and this would be associated with
reductions in ROS. In Study 1, Simvastatin reduced resting MSNA (75±5 baseline
vs. 65±5 statin bursts/100 heart beats, P<0.05). Likewise, in Study 2,
Simvastatin also decreased resting MSNA (59±5 placebo vs. 45±6 statin
bursts/100 heart beats, P<0.05). In addition, statin therapy significantly
reduced total ROS and superoxide. As expected, cholesterol was reduced after
Simvastatin. Collectively, these findings indicate that short-term statin
therapy concomitantly reduces resting MSNA and total ROS and superoxide in HF
patients. Thus, in addition to lowering cholesterol, statins may also be
beneficial in reducing sympathetic overactivity and oxidative stress in HF
patients.
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