Carotid plaque age is a feature of plaque stability inversely related to levels of plasma XXXX .

@entity1 @entity64 @entity583 @entity2690 @entity397 @entity3209 @entity715 @entity543
BACKGROUND: The stability of atherosclerotic plaques determines the risk for @entity397 , which may lead to @entity715 formation and potentially severe clinical complications such as @entity583 and @entity64 . Although the rate of plaque formation may be important for plaque stability, this process is not well understood. We took advantage of the atmospheric @entity3209 -declination curve (a result of the atomic bomb tests in the 1950s and 1960s) to determine the average biological age of carotid plaques. METHODOLOGY/PRINCIPAL FINDING: The cores of carotid plaques were dissected from 29 well-characterized, symptomatic @entity1 with @entity543 and analyzed for @entity3209 content by accelerator mass spectrometry. The average plaque age (i.e. formation time) was 9.6  3.3 years. All but two plaques had formed within 5-15 years before surgery. Plaque age was not associated with the chronological ages of the @entity1 but was inversely related to plasma @entity2690 levels (p=0.0014). Most plaques were echo-lucent rather than echo-rich (2.24  0.97, range 1-5). However, plaques in the lowest tercile of plaque age (most recently formed) were characterized by further instability with a higher content of lipids and macrophages (67.8  12.4 vs. 50.4  6.2, p=0.00005; 57.6  26.1 vs. 39.8  25.7, p<0.0005, respectively), less collagen (45.3  6.1 vs. 51.1  9.8, p<0.05), and fewer smooth muscle cells (130  31 vs. 141  21, p<0.05) than plaques in the highest tercile. Microarray analysis of plaques in the lowest tercile also showed increased activity of genes involved in immune responses and oxidative phosphorylation. CONCLUSIONS/SIGNIFICANCE: Our results show, for the first time, that plaque age, as judge by relative incorporation of @entity3209 , can improve our understanding of carotid plaque stability and therefore risk for clinical complications. Our results also suggest that levels of plasma @entity2690 might be involved in determining carotid plaque age.
