[Decrease ApoB/ApoA-1 ratio and cardiovascular risk improvement: a tadalafil pleiotropic effect? Preliminary study on...

Recognition of erectile dysfunction (ED) as an early sign of systemic cardiovascular disease offers an opportunity for prevention. Cardiac risk assessment may deserve measurement of Apolipoprotein B/Apolipoprotein A-1 ratio. An elevated ApoB/ApoA-1 ratio is a risk factor for future coronary artery disease. ApoA-1 production, which is recognized as a cardioprotective lipid fraction, is down regulated by NFkappaB activation in vitro. Because inhibition of phosphodiesterases (PDEs) 5, 6 and 9 negatively attenuates NFkappaB translocation/activation, tadalafil, a selective PDE 5 inhibitor used for treatment of ED could present some interesting pleiotropic effects. The objective of this open study is to test the hypothesis that tadalafil treatment could decrease serum ApoB/ApoA-1 ratio.

Ten healthy men without any complain of ED or known cardiovascular risk factors were administered tadalafil 10mg intake on alternate days for 4 weeks. Lipid profile with total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, ApoA-1 and ApoB, was assessed at baseline (T0), after 2weeks (T1), at the end of the treatment period (T2) and after 2weeks of wash-out follow-up (T3).

ApoB/ApoA-1 ratio was significantly decreased during treatment (mean+/-SEM, T0: 0.80+/-0.11, T1: 0.64+/-0.06, T2: 0.65+/-0.06; p<0.05) and remained lower after wash-out (T3: 0.67+/-0.05; p=0.08). Serum ApoA-1 (mg/dl) increased but not significantly during the treatment period (15.2+/-8.8, 16.5+/-7.9, 16.9+/-6, 15.3+/-7, p=0.26) and ApoB (mg/dl) significantly decreased (11.7+/-10.8, 10.3+/-8.4, 10.6+/-9.9, 10.2+/-8.6, p=0.03). HDL and LDL cholesterol were unchanged.

This preliminary study showed the interest of PDE 5 inhibitors to decrease the cardiac risk factor ApoB/ApoA-1 ratio. Randomised controlled studies with longer follow-up are needed to confirm those results.