Relation between Vascular Risk Factors and Carotid Plaque Cell Composition and Viability in Elderly Patients

Summary, in English

Objectives: Carotid stenosis is a crucial cause of ischemic stroke. Recent studies suggest that one of

the most important effects of lipid-lowering statins is to stabilize vulnerable plaques. However, it

remains to be determined if this effect is secondary to the lowering of plasma cholesterol levels or due

to a direct effect of statins on plaques stability.

Design and main outcome measures: In this study we have analyzed if plaque cell composition and the

frequency of apoptotic DNA fragmentation are related to cholesterol levels or any of the major risk

factors for vascular disease. The study group consisted of 49 patients undergoing carotid

endarterectomy. The plaques were stained by immunohistochemical and TUNEL techniques and

scored semi quantitatively by a blinded observer.

Results: Rupture sites contained significantly more TUNEL-positive cells and T-cells, but less smooth

muscle cells than intact areas of the fibrous cap. Plaques from hypercholesterolemic patients were

found to have less TUNEL-positive cells, but otherwise hypercholesterolemia, low HDL cholesterol,

hypertension, diabetes and smoking did not influence plaque cell composition or the frequency of

TUNEL-positive cells.

Conclusions: Our observations suggest that there are no associations between major vascular risk factors

and plaque cell composition. Accordingly, they favor the notion that the effects of statins are due to a

direct effect on plaque structure rather than solely secondary to lowering of plasma cholesterol.