Comparison of the impact of atorvastatin and simvastatin on apoA-I kinetics in men.
BACKGROUND
The impact of simvastatin and atorvastatin, two HMG-CoA inhibitors, on plasma HDL-C concentrations has been shown to be inconsistent, simvastatin being reported to induce greater increases in HDL-C than atorvastatin. The physiological mechanisms underlying this diverging effect are still unknown.


OBJECTIVE
To compare the impact of simvastatin and atorvastatin on apoA-I kinetics in vivo.


METHODS
In this double-blind, cross-over study, seven men with relatively low baseline HDL-C were assigned in random order to one of two experimental 8-week treatments (atorvastatin 40 mg or simvastatin 80 mg), each separated by a 6-week washout period. After each phase, apoA-I kinetics were measured using a primed-constant infusion of l-(5,5,5-D3) leucine for 12 h with patients being kept in constant fed, steady state. Isotopic enrichment of apoA-I over time was assessed by gas chromatography-mass spectrometry and kinetic parameters were calculated by multicompartmental modeling.


RESULTS
Both treatments reduced plasma LDL-C levels to a similar extent while HDL-C levels remained statistically unchanged after both experimental phases. However, compared to atorvastatin, plasma apoA-I concentrations were significantly higher after treatment with simvastatin (1.33 +/- 0.07 g/L versus 1.23 +/- 0.07 g/L, P = 0.05). Treatment with simvastatin also induced a significant increase in apoA-I production rate compared to atorvastatin (15.2 +/- 3.0 mg/kg/d versus 13.2 +/- 2.6 mg/kg/d, P = 0.05). There was no statistical difference in apoA-1 fractional catabolic rate between simvastatin and atorvastatin (0.26 +/- 0.05 pool/d versus 0.24 +/- 0.04 pool/d).


CONCLUSIONS
These results suggest that the diverging impact of simvastatin and atorvastatin on plasma HDL-C levels in humans may be attributable, at least partly, to a greater production rate of apoA-I with simvastatin.
Mauger
Jean-François
JF
Institute on Nutraceuticals and Functional Foods, 2440 Boul Hochelaga, Local 2742, Laval University, Que., Canada G1K 7P4.
Couture
Patrick
P
Paradis
Marie-Eve
ME
Lamarche
Benoît
B
D016632:Apolipoprotein A-I / Q000097:blood*; D000069059:Atorvastatin; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006538:Heptanoic Acids / Q000627:therapeutic use*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D006937:Hypercholesterolemia / Q000097:blood* / Q000188:drug therapy*; D007700:Kinetics; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011758:Pyrroles / Q000627:therapeutic use*; D019821:Simvastatin / Q000627:therapeutic use*
D016632:Apolipoprotein A-I; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008055:Lipids; D011758:Pyrroles; D000069059:Atorvastatin; D019821:Simvastatin