Vulnerable Plaque'

PURPOSE: Vulnerable plaques are characterized by a myxoid matrix, necrotic lipidic core, reactive oxygen species, and high levels of microorganisms. Aerobic microbes such as Chlamydophila pneumoniae and Mycoplasma pneumoniae usually do not survive in oxidative stress media. Archaea are anaerobic microbes with powerful anti-oxidative enzymes that allow detoxification of free radicals whose presence might favor the survival of aerobic microorganisms. We searched for archaeal organisms in vulnerable plaques, and possible associations with myxoid matrix, chlamydia, and mycoplasma bodies. METHODS: Twenty-nine tissue samples from 13 coronary artherectomies from large excentric ostial or bifurcational lesions were studied using optical and electron microscopy. Infectious agents compatible with archaea, chlamydia, and mycoplasma were semiquantified using electron micrographs and correlated with the amounts of fibromuscular tissue, myxoid matrix, and foam cells, as determined from semi-thin sections. Six of the cases were also submitted to polymerase chain reaction with archaeal primers. RESULTS: All 13 specimens showed archaeal-compatible structures and chlamydial and mycoplasmal bodies in at least 1 sample. There was a positive correlation between extent of the of myxoid matrix and archaeal bodies (r = 0.44, P = 0.02); between archaeal and mycoplasmal bodies (r = 0.41, P = 0.03), and between chlamydial bodies and foam cells (r = 0.42; P = 0.03). The PCR test was positive for archaeal DNA in 4 of the 6 fragments. DISCUSSION: DNA and forms suggestive of archaea are present in vulnerable plaques and may have a fundamental role in the proliferation of mycoplasma and chlamydia. This seems to be the first description of apparently pathogenic archaea in human internal organ lesions.

The history of atherosclerosis and cardiovascular disease dates back to ancient times. From the teachings of Galen to the response-to-injury hypothesis of Russel Ross, we have now arrived at the concept of the vulnerable plaque. Next to the development of new treatment options for patients with atherosclerosis, also novel diagnostic imaging techniques have been developed to visualise the arterial wall and to characterise plaque composition. In this article the historical context of atherosclerosis and the attempts towards a noninvasive therapy for patients with atherosclerotic diseases are described. (Neth Heart J 2009;17:140-4.).

Summary Rupture of vulnerable plaques is the main cause of acute coronary syndromes and my- ocardial infarctions. Identification of these vulnerable plaques is therefore essential to en- able the development of treatment modalities to stabilise them. Several intra-vascular tech- nologies, investigating coronary areas that will be responsible for future events, are un- derlined in this review. The ideal technique would

Background—Catabolism of the extracellular matrix (ECM) contributes to vascular remodeling in health and disease. Although metalloenzymes and cysteinyl proteinases have garnered much attention in this regard, the role of serine-dependent proteinases in vascular ECM degradation during atherogenesis remains unknown. We recently discovered the presence of the metalloproteinase MMP-8, traditionally associated only with neutrophils, in atheroma- related cells. Human neutrophil elastase

Vascularization is an exciting and complex mechanism involving angiogenesis and arteriogenesis. The metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) are associated with multiple metabolic toxicities, which result in reactive oxygen species (ROS) due to an elevated tension of oxidative-redox stress and an accelerated atherosclerosis termed atheroscleropathy. This atheroscleropathy is associated with accelerated angiogenesis within the vulnerable, thin-cap fibro-atheroma, prone to rupture resulting in acute coronary syndromes (ACS). The resulting intimopathy with its neovascularization due to angiogenesis of the adventitial vasa vasorum (Vv) is prone to intraplaque hemorrhage (IPH). These IPH are associated with destabilization of the vulnerable plaques resulting in plaque erosion and plaque rupture resulting in ACS. In atheroscleropathy the adventitial Vv invades the plaque in a malignant-like fashion and concurrently is associated with chronic inflammation, as macrophages...

The arterial system is more than an intricate plumbing system for the transport of blood; it is a highly complex organ that interacts with its environment. The major function of the vessel wall, and more specifically the endothelial lining, is to maintain an adequate blood supply to the end organ that it is supplying. This is achieved by regulatory mech- anisms that control vascular tone, inflammation and anticoagulation. The vessel wall requires an adequate supply of nutrients to maintain healthy function, and whilst some of these can be derived from the vessel lumen itself, the walls of larger arteries (exceeding 1mm in diameter) receive an additional supply from the vasa vasorum (vv), which is a vascular network serving the arterial wall. The vessels of the vv originate either from the parent artery or from a neighbour, pass into the outer layer of the vessel wall, and break up into a capillary network reaching the inner parts of the vessel wall. As with any organ, the vessel wal...

The goal of this article is to illustrate the main invasive and noninvasive diagnostic modalities to image the vulnerable coronary plaque, which is responsible for acute coronary syndrome. The main epidemiologic and histological issues are briefly discussed in order to provide an adequate background. Comprehensive coronary atherosclerosis imaging should involve visualization of the entire coronary artery tree and plaque characterization, including three-dimensional morphology, relationship with the lumen, composition, vascular remodelling and presence of inflammation. No single technique provides such a comprehensive description, and no available modality extensively identifies the vulnerable plaque. In particular, we describe multislice computed tomography, which at present seems to be the most promising noninvasive tool for an exhaustive image-based quantification of coronary atherosclerosis.

Purpose Membrane type 1 matrix metalloproteinase (MT1-MMP) activates pro-MMP-2 and pro-MMP-13 to their active forms and plays important roles in the destabilization of atherosclerotic plaques. This study sought to determine the usefulness of 99mTc-labelled monoclonal antibody (mAb), recognizing MT1-MMP, for imaging atherosclerosis in a rabbit model (WHHLMI rabbits). Methods Anti-MT1-MMP monoclonal IgG3 and negative control IgG3 were radiolabelled with 99mTc after derivatization with 6-hydrazinonicotinic acid (HYNIC) to yield 99mTc-MT1-MMP mAb and 99mTc-IgG3, respectively. WHHLMI and control rabbits were injected with these radio-probes. The aorta was removed and radioactivity was measured at 24 h after the injection. Autoradiography and histological studies were performed. Results 99mTc-MT1-MMP mAb accumulation in WHHLMI rabbit aortas was 5.4-fold higher than that of control rabbits. Regional 99mTc-MT1-MMP mAb accumulation was positively correlated with MT1-MMP expression (r = 0.59, p < 0.0001), while 99mTc-IgG3 accumulation was independent of MT1-MMP expression (r = 0.03, p = NS). The highest 99mTc-MT1-MMP mAb accumulation was found in atheromatous lesions (4.8 ± 1.9, %ID×BW/mm2 × 102), followed in decreasing order by fibroatheromatous (1.8 ± 1.3), collagen-rich (1.6 ± 1.0) and neointimal lesions (1.5 ± 1.5). In contrast, 99mTc-IgG3 accumulation was almost independent of the histological grade of lesions. Conclusion Higher 99mTc-MT1-MMP mAb accumulation in grade IV atheroma was shown in comparison with neointimal lesions or other more stable lesions. Nuclear imaging with 99mTc-MT1-MMP mAb, in combination with CT and MRI, could provide new diagnostic imaging capabilities for detecting vulnerable plaques, although further investigations to improve target to blood ratios are strongly required.