Effect of increasing doses of Rosuvastatin and Atorvastatin on apolipoproteins, enzymes and lipid transfer proteins involved in lipoprotein metabolism and inflammatory parameters

Abstract

This paper contains detailed results of a sub-population of the prospective randomized RADAR (Rosuvastatin and Atorvastatin in different Dosages And Reverse cholesterol transport) study.

Objective:

Statin treatment results in substantially decreased incidence of cardiovascular events but the exact pathophysiological mechanism of their beneficial effect is yet unclear. We aimed to examine the effects of up-titrated doses of two widely used statins (atorvastatin (ATOR) and rosuvastatin (ROSU)) on parameters involved in lipoprotein metabolism, in patients with low high density lipoprotein cholesterol values (HDL-C).

Research design and methods:

In this RADAR substudy, 80 patients, aged 40–80 years, with known cardiovascular disease and low HDL-C (<1.0 mmol/l), were randomized to receive, after an initial 6 week dietary run-in phase, either ATOR 20 mg (n = 41) or ROSU 10 mg (n = 39). The doses were up-titrated (in 6 week intervals) to 80 mg of ATOR or 40 mg of ROSU at 12 weeks. Serum lipoproteins and lipoprotein metabolism parameters were measured at baseline and at 6 and 18 weeks of follow up.

Results:

Both statins significantly reduced total cholesterol (TChol) and non-HDL-C values with ROSU being more effective for the doses studied (p < 0.05). No statistically significant effect on HDL-C was observed for either statin. Apolipoproteins (apo) B, CI, CIII, AV and E were significantly reduced in both groups (p < 0.05), while the ratio of HDL particles containing both apoAI and apoAII (LpAI-AII) over HDL containing apoAI alone (LpAI) was changed for both statins with the decrease of LpAI being more prominent in the ATOR group (p = 0.028). Cholesterol ester transfer protein (CETP) mass and activity, phospholipid transfer protein (PLTP) activity and lipoprotein-associated phospholipase A2 (Lp-PLA2) mass and activity were all significantly reduced in both treatment groups over the follow-up period (p < 0.001). ATOR displayed a more prominent decrease of PLTP activity compared to ROSU (p = 0.043), while ROSU displayed a more prominent decrease of Lp-PLA2 activity compared to ATOR (p = 0.04). Both statins effectively reduced, in a dose-dependent way, high sensitivity C-reactive protein values over time, while no effect on the levels of circulating inter cellular adhesion molecule 1 (cICAM-1) was observed.

Conclusions:

The effects of statin treatment extend further and beyond a mere TChol and LDL cholesterol reduction, as demonstrated by the aforementioned alterations of lipoproteins, enzymes and lipid transfer proteins involved in lipoprotein metabolism and pro-atherogenic and inflammatory molecules. ROSU and ATOR displayed a similar pattern of effect on lipid metabolism with discrete differences in the magnitude of this effect in certain variables. Despite the limitations of small population size and lack of clinical end points, reported data provide an insight for the possible pathophysiological mechanisms implicated in the effect of increasing dosages of different statin treatments.

Key words:

• Apolipoproteins
• C-reactive protein
• Enzymes
• Hydroxymethylglutaryl-CoA reductase inhibitors
• Lipid metabolism

Transparency

Declaration of funding

The RADAR study was financially supported by Astra-Zeneca.

Declaration of financial/other relationships

J.W.J. has disclosed that he is an established clinical investigator of the Netherlands Heart Foundation (2001D032). He has received research grants from, and was a speaker on, CME accredited meetings sponsored by Astellas, Astra-Zeneca, Biotronik, Boston Scientific, Bristol Myers Squibb, Cordis, Daiichi Sankyo, Ely Lilly, Medtronic, Merck-Schering-Plough, Pfizer, Orbus Neich, Novartis, Roche and Servier. The rest of the co-authors have stated that they have no conflicts of interest including specific financial interests and relationships or any other commercial entity relevant to, or that could potentially benefit from, the publication/disclosure of the subject matter or materials discussed in the manuscript. The authors thank the Hellenic Society of Cardiology for financially supporting, through a clinical and research scholarship, one of the authors (I.K.K.) for his fellowship in Netherlands.

Acknowledgements

The authors have disclosed that they had no outside editorial assistance in preparing this manuscript.