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Effects of statins in thrombosis and aortic lesion development in a dyslipemic rabbit model
J Alfon1, C Pueyo Palazon, T Royo
1Cardiovascular Research Center, CSIC-HSCSP-UAB, Barcelona, Spain.
Abstract:
HMG-CoA reductase inhibitors (statins) are effective in primary and secondary prevention of coronary heart disease. The mechanism of action is mainly attributed to their plasma cholesterol lowering activity, although additional effects have been suggested. Our objective was to study whether atorvastatin and simvastatin exhibited an inhibitory effect on platelet deposition onto a triggering damaged vessel wall in addition to an antiatherosclerotic effect in the dyslipemic rabbit model. Statins were administered at identical doses of 2.5 mg/kg/day with a hyperlipidemic diet during 10 weeks. Both drugs similarly lowered total cholesterol and, moderately, triglycerides. Mural platelet deposition on damaged vessel wall placed in an ex-vivo flow perfusion system was reduced in atorvastatin treated animals (39.7+/-6.2 X 10(6) PLT/cm2) vs. controls (94.8+/-15.9 x 10(6) PLT/cm2, p <0.02). Simvastatin reduced aortic fatty streak surface coverage (31,7+/-5.3%) vs. controls (47.9+/-4.1%, p <0.005) and intimal thickening in thoracic aorta (0.15+/-0.05 intima to total area ratio in simvastatin treated animals vs. 0.36+/-0.03 in control animals, p <0.05). Atherosclerotic fatty streak coverage correlated positively with total cholesterol, tryglicerides and LDL-cholesterol levels in all groups. HMG-CoA reductase inhibitors similarly lowered plasma lipids but exhibited significantly different effects in the modulation of atherosclerotic development and platelet response at the tested dose. Therefore, the effect of statins on the progression and manifestation of cardiovascular disease might be also mediated by regulating platelet response to vessel injury.
Insights
Statins (HMG-CoA reductase inhibitors) reduce cholesterol and may also prevent cardiovascular disease by inhibiting platelet deposition on damaged blood vessels. This study found atorvastatin and simvastatin had different effects on atherosclerosis and platelet response in rabbits.
Area of Science:
- Cardiovascular Pharmacology
- Atherosclerosis Research
- Platelet Biology
Background:
- HMG-CoA reductase inhibitors (statins) are widely used for cardiovascular disease prevention, primarily for their lipid-lowering effects.
- While cholesterol reduction is their main mechanism, other pleiotropic effects on cardiovascular health are suspected.
- The differential impact of various statins on platelet function and atherosclerosis beyond lipid modification requires further investigation.
Purpose of the Study:
- To investigate the anti-atherosclerotic and anti-platelet deposition effects of atorvastatin and simvastatin in a dyslipidemic rabbit model.
- To compare the efficacy of atorvastatin and simvastatin at identical doses in modulating cardiovascular disease markers.
- To explore potential mechanisms of statin action beyond cholesterol reduction in cardiovascular disease.
Main Methods:
- Dyslipidemic rabbits were treated with atorvastatin or simvastatin (2.5 mg/kg/day) alongside a hyperlipidemic diet for 10 weeks.
- Plasma lipid levels (total cholesterol, triglycerides, LDL-cholesterol) were measured.
- Ex-vivo platelet deposition on damaged vessel walls was assessed using a flow perfusion system.
- Atherosclerotic lesion development, including fatty streak coverage and intimal thickening, was quantified in the aorta.
Main Results:
- Both atorvastatin and simvastatin significantly reduced total cholesterol and moderately reduced triglycerides.
- Atorvastatin significantly reduced mural platelet deposition on damaged vessel walls compared to controls.
- Simvastatin demonstrated a significant reduction in aortic fatty streak coverage and intimal thickening compared to controls.
- Atherosclerotic lesion progression positively correlated with lipid levels across all groups.
Conclusions:
- While both statins effectively lowered plasma lipids, they exhibited distinct effects on atherosclerosis development and platelet response in this model.
- Atorvastatin showed a notable inhibitory effect on platelet deposition, suggesting a direct impact on thrombotic processes.
- Simvastatin effectively reduced atherosclerotic lesion progression, highlighting its anti-atherosclerotic capabilities.
- These findings suggest that the cardiovascular benefits of statins may also stem from their ability to modulate platelet reactivity and inflammatory responses to vascular injury, in addition to lipid lowering.