Antioxidant Treatment Associated with Sildenafil Reduces Monocyte Activation and Markers of Endothelial Damage in Patients with Diabetic Erectile Dysfunction: A Double-Blind, Placebo-Controlled Study

ObjectiveTo investigate the synergic effect of propionyl L-carnitine (PLC) plus sildenafil in reducing monocyte oxidative activity and endothelial dysfunction markers in diabetic patients with erectile dysfunction (ED).MethodsThirty-two type 2 diabetic patients with ED (according to the International Index of Erectile Function-5 [IIEF-5]) were randomized to receive PLC (2 g/d) alone (n = 8) or combined with sildenafil (50 mg/d twice weekly) (n = 8), sildenafil alone (50 mg/d twice weekly) (n = 8), or placebo (n = 8) in a double-blind, fixed-dose study.Monocyte oxidative activity (stimulation index [SI]), intercellular adhesion molecule-1 [ICAM-1], P-selectin, advanced glycation end product (AGE) levels, Doppler sonography (recording peak systolic velocity [PSV]; end diastolic velocity [EDV]; systolic wave time [SWT]; resistive index [RI]), and IIEF score were evaluated before and after 12 wk of treatment; IIEF-5 was evaluated again 4 wk posttreatment.ResultsSI was reduced by treatment with PLC alone or combined with sildenafil (p < 0.05). In patients treated with PLC plus sildenafil, a decrease in ICAM-1, P-selectin, and EDV values was observed compared with patients treated with sildenafil alone (p < 0.05, p < 0.01, p < 0.001, respectively). IIEF-5 improved in all patients treated with PLC plus sildenafil or sildenafil alone (p < 0.03, p < 0.05, respectively). Four weeks posttreatment, patients treated with PLC plus sildenafil maintained the improvement of the IIEF-5 compared with patients on sildenafil alone (p = 0.05). In patients on PLC treatment (with or without sildenafil), SI was correlated with IIEF-5 (p < 0.001), glycemia with STW (p < 0.03), and AGEs with IIEF-5 (p < 0.01).ConclusionPLC plus sildenafil was more effective in reducing SI and endothelial dysfunction markers in patients with type 2 diabetes and ED.