HMG-CoA reductase inhibitors (statins) inhibit cholesterol biosynthesis, and also decrease the formation of isoprenoid intermediates required for the activation of Rho kinase (ROCK) pathway. ROCK pathway plays pivotal roles in cardiovascular diseases including arteriosclerosis. It has been implicated that inhibition of ROCK can reverse vascular dysfunction in humans with atherosclerosis. However, it is not clear whether statins, at doses used to lower cholesterol levels, inhibit ROCK activity in humans with atherosclerosis. Methods
We treated 40 subjects with stable atherosclerosis with rosuvastatin 10 mg/day, or rosuvastatin 40 mg/day for 28 days in a randomized, double-blinded study. We assessed the change in the lipid levels, C-reactive protein (CRP), ROCK activity, and flow-mediated dilation (FMD) of the brachial artery before and after statins therapy. Results
Treatment with rosuvastatin 10 mg and 40 mg significantly reduced LDL cholesterol by 43.2% to 55.9% and increased FMD by 29.3% to 42.5% (p<0.05 for both compared with baselines). Both doses inhibited ROCK activity (p<0.05), and the extent of inhibition was greater with rosuvastatin 40 mg compared with 10 mg (p<0.05). Only rosuvastatin 40 mg significantly reduced hsCRP (p<0.05).There was no correlation between changes in ROCK activity and changes in low-density lipoprotein cholesterol (r=0.37, p>0.05 vs. r=0.41, p>0.05) among patients randomized to rosuvastatin 10 mg group or 40 mg group. There was a correlation between ROCK inhibition and change in FMD among patients with rosuvastatin 10 mg therapy (r=0.43, p<0.05), and 40 mg therapy (r=0.54, p<0.05). Correlation was found between changes in ROCK inhibition and changes in CRP in rosuvastatin 40 mg/day group (r=0.47, p<0.05). Conclusion
These results demonstrate that high dose rosuvastatin exerts greater effects on LDL-C, ROCK activity, and CRP than low dose rosuvastatin. These findings provide clinical evidence that statins are effective in improving endothelium dysfunction by a cholesterol-independent mechanism in patients with atherosclerosis.