New insights into plaque stabilisation by lipid lowering

Area of Science:

• Cardiovascular Medicine
• Inflammation Research
• Atherosclerosis Biology

Background:

• Acute coronary events stem from thrombosis on disrupted atherosclerotic plaques.
• Plaque stability, determined by fibrous cap integrity and core composition, is crucial for clinical outcomes.
• Inflammation significantly impacts plaque stability, with higher leucocytic infiltrates in ruptured plaques.

Purpose of the Study:

• To investigate the hypothesis that lipid lowering reduces inflammation within atherosclerotic lesions.
• To elucidate the mechanisms by which lipid lowering influences plaque stability.
• To provide a mechanistic understanding for the observed reduction in cardiovascular events with lipid-lowering treatments.

Main Methods:

• Experimental atherosclerosis model in rabbits.
• Assessment of macrophage infiltration in plaques.
• Quantification of collagenolytic enzyme (MMP-1) expression.
• Measurement of interstitial collagen content in the fibrous cap.

Main Results:

• Lipid lowering reduced macrophage numbers in atherosclerotic plaques.
• Lipid lowering decreased the expression of the collagenolytic enzyme MMP-1.
• Lipid lowering increased interstitial collagen content, reinforcing the plaque's fibrous skeleton.

Conclusions:

• Lipid lowering stabilizes atherosclerotic plaques by reducing local inflammation.
• Stabilization of the fibrous cap renders atheroma less prone to rupture and thrombotic complications.
• These findings offer a mechanistic explanation for the benefits of lipid-lowering agents in preventing cardiovascular and cerebrovascular events.