FIG. 5.

Effects of statins on vascular BH₄ and redox state of the IMA in vivo and ex vivo. Three-day preoperative administration of atorvastatin (40 mg/day) in patients undergoing bypass surgery significantly reduced O₂⁻ generation (A), restored eNOS coupling (B), and increased BH₄ availability (C) versus the placebo arm in the wall of the IMA. Similarly, exposure of human IMA segments to atorvastatin ex vivo increased vascular BH₄ content (D) and gene expression of GCH1 (E). Inhibition of GTPCH by DAHP prevented the ex vivo effects of atorvastatin on vascular BH₄ (F, *p<0.05 vs. control, **p<0.01 vs. control). Adapted from Ref. (5). IMA, internal mammary artery.