Origin of lipid and cholesterol in experimental thromboatherosclerosis

Diagnostic Accuracy of Optical Frequency Domain Imaging for Identifying Necrotic Cores with Intraplaque Hemorrhage in Advanced Human Carotid Plaques

This study investigated whether optical frequency domain imaging (OFDI) can identify carotid artery vulnerable plaque characteristics, focusing on lipid-rich necrotic core (NC) and intraplaque hemorrhage (IPH). Fourteen patients scheduled for carotid endarterectomy underwent OFDI scan during preoperative angiography. Atherosclerotic plaque specimens obtained from carotid endarterectomy were cut every 3-4 mm into 4-μm transverse cross-sections and stained with standard methods. Each cross-section was matched with OFDI, and histologically classified into either fibrous, calcific, pathological intimal thickening (PIT), and NC. Of 75 histologic cross-sections, 6 were categorized as fibrous (8%), 18 as calcific (24%), 9 as PIT (12%), and 42 as NC (56%). Tissues categorized as NC had significantly higher OFDI signal attenuation rates than the other tissues (p <0.001), followed by PIT, calcific, and fibrous tissues. The receiver operating characteristic analysis indicated that attenuation rates of >0.023 and >0.031 predicted the presence of NC and IPH with high areas under the curve of 0.91 and 0.88, respectively. OFDI provides potential capability for the detection of NCs with IPH of carotid artery plaques by quantitatively analyzing the attenuation rate.

Comparison of angioscopy and histopathology for the evaluation of carotid plaque characteristics: an ex vivo validation study

Intravascular angioscopy is widely used for evaluating plaque characteristics through the plaque color in the coronary artery. This study evaluated whether angioscopy is capable of identifying various plaque morphologies, including necrotic core and intraplaque hemorrhage (IPH) in the carotid artery. Nine patients underwent carotid endarterectomy for carotid artery stenosis, and these specimens were imaged ex vivo by angioscopy within 6 h. An angioscopic examination of carotid plaque evaluated its color intensity as follows: white, yellow, or red. The IPH area, necrotic core area, and fibrous cap thickness was measured on histological sections at each site. A total of 7 plaques were graded as white plaques, 10 as yellow, and 8 as red by angioscopy. The IPH area and the percent area occupied by IPH were larger in red and yellow plaques than in white plaques (10.7 ± 9.3 mm², 9.4 ± 7.8 mm², and 2.2 ± 1.7 mm², respectively, P = 0.074; and 25 ± 10%, 19 ± 13%, and 7 ± 5%, respectively, P = 0.008). Furthermore, the thickness of the fibrous cap was significantly thinner in red plaques than in yellow and white plaques (128 ± 34 µm, 328 ± 136 µm, and 285 ± 102 µm, respectively, P = 0.002). The ROC analysis for predicting a presence of red plaques identified that the optimal cutoff value of fibrous cap thickness was 181 µm (area under the curve = 0.987, 100% sensitivity, 90% specificity). The prevalence of red plaques on intravascular angioscopy may represent the existence of plaques containing relatively larger necrotic core and IPH with a thin fibrous cap.

Immunohistochemical study of intimal microvessels in coronary atherosclerosis

Two hundred ninety-nine human coronary artery paraffin-embedded tissue blocks were examined for intimal microvessel invasion by probing for factor VIII-associated antigen with indirect immunofluorescence and high resolution confocal microscopy. The results obtained confirm that intimal microvessels originate in the adventitia and show that the richness of intimal microvessels is strongly positively correlated with intimal thickness and negatively correlated with relative lumen size. A number of plasma constituents were examined in serial sections. Comparison of immunofluorescence distribution patterns of these components with intimal microvessel distribution patterns reveals that intimal microvessels leak plasma albumin into artery walls, exude fibrinogen, and are associated with the build-up of plasma cells within atherosclerotic lesions. Therefore, intimal microvessels are demonstrated to play important roles in the development of atherosclerosis.

Hypothesis: ischaemic plaque necrosis as the initiator of unstable angina/acute myocardial infarction?

1. Coronary atherosclerotic plaque complications are important in precipitating acute coronary events such as unstable angina and myocardial infarction. 2. The hypothesis is put forward that plaque complications are initiated by increases in local coronary artery tone sufficient to cut off the vasa vasorum blood supply to the plaque and result in its ischaemic necrosis.

Anti-inflammatory drugs in experimental atherosclerosis. Part 6. Combination therapy with steroid and non-steroid agents

The pathological changes which accompany enhanced cholesterol deposition in atherosclerosis include inflammatory responses mediated by the prostaglandin cyclooxygenase and lipoxygenase-leukotriene metabolite of the arachidonic acid cascade. Cortisone suppresses arachidonic acid release, whereas non-steroid anti-inflammatory drugs inhibit principally the cyclooxygenase enzyme. Groups of New Zealand white rabbits were fed a 1% cholesterol diet for 12 weeks. Diets of selected groups were further supplemented daily with the non-steroid anti-inflammatory drugs phenylbutazone (100 mg), oxyphenylbutazone (240 mg), flufenamic acid (100 mg), either singly or in combination with cortisone acetate (10 mg or 5 mg), or 9-alpha-fluorohydrocortisone (30 micrograms or 200 micrograms). Serum lipid levels were measured at 0, 4, 8 and 12 weeks, and atherosclerotic plaque intensity in thoracic aorta was measured at 12 weeks using a planimetric technique: serum cholesterol levels in control groups increased from 38 +/- 5 to 1190 +/- 139 mg/100 ml. Neither the rate of increase nor the final lipid values attained were significantly changed by the non-steroid drugs. The non-steroid drugs reduced plaque coverage by about one third (phenylbutazone 34 +/- 10%, flufenamic acid 36 +/- 11%) compared to controls. In combination therapy, addition of cortisone acetate resulted in further plaque suppression. Cortisone 10 mg + phenylbutazone gave 100% suppression; cortisone 5 mg + phenylbutazone gave 82 +/- 18%, and cortisone 5 mg + flufenamic acid gave 84 +/- 3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular pathology of homozygous familial hypercholesterolemia

Tissues were studied from four subjects with homozygous familial hypercholesterolemia (FH). The specimens consisted of tissues obtained from a 20-week-old fetus at autopsy, samples from a 9-year-old girl during open-heart surgery, and biopsies of cutaneous xanthomas from a 13-year-old girl and a 21-year-old man. The FH fetus, but not the 3 control fetuses, exhibited multifocal lipid deposition particularly involving the stromal cells of the thymus, spleen, and skin and both the stromal and parenchymal cells of the kidney. Only one minute focus of intimal lipid accumulation was found in the aorta and coronary arteries of the FH fetus. A segment of the ascending aorta from the 9-year-old girl showed: 1) foam-cell transformation of many medial smooth-muscle cells, 2) abnormal vascularization of the inner media and intima, and 3) intimal involvement by a typical artherosclerotic plaque with lipid deposits in thin, elongated cells that showed some myocytic features and in foam cells that lacked such features. The mitral and aortic valves of this patient also contained numerous foam cells and showed mild to moderate fibrous thickening. A segment of the saphenous vein, however, contained no lipid deposits. The three xanthomas from two FH homozygotes exhibited marked lipid accumulation in histiocytic foam cells but no lipid deposits in the endothelium of blood vessels in the lesions. The findings in this study, in conjunction with those reported in studies of other FH homozygotes, indicate that homozygous FH is characterized by accelerated atherosclerosis and prominent lipid accumulation in macrophages and other stromal cells of the aortic and mitral valves, skin, tendon, and, varibly, in other extravascular sites. Since most of the intracellular lipid was in the form of non-membrane-bound neutral lipid droplets, it appears that the cytoplasm is the major site of lipid storage in this disease.

Stress and disease: the missing link. A vasospastic theory. II. The nature of degenerative arterial disease

An analysis of the evidence indicates that the initiation and progress of atherosclerosis might well be explained by repeated bouts of arterial constriction in relation to life stresses, through increased blood flow velocity and turbulence at points of constriction, and consequent endothelial damage, plasma insudation into the wall, and intimal smooth muscle cell - connective tissue proliferation.

Lipidization induced by bone and glass fragments within an arterial plaque

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Focal lipid lesions in blood vessels due to erythrocytes and platelets. Experimental observations on goats and rabbits

Experiments on goats and rabbits living on a normal diet demonstrated that the lipid associated with organizing thrombi became concentrated in fibrosed focal lesions of blood vessels. The lipid that appeared during organization of lysed erythrocytes underwent changes similar to those of lipid in thrombi. From this it was concluded that what red cells there were in the thrombi contributed to the total lipid present.

These observations are pertinent to the pathogenesis of atherosclerosis, because they help to explain the thrombosis characteristically associated with this disease, and how lipid can be delivered to restricted regions of the arterial intima.

Immunity of the mature thrombo-atherosclerotic plaque to hypercholesteraemia

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INDUCTION OF HEMORRHAGES IN PRE-EXISTING ARTERIAL PLAQUES

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INDUCTION OF THROMBI UPON PRE-EXISTING ARTERIAL PLAQUES

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THE ATHEROGENIC POTENTIAL OF DIETARY DERIVED CHOLESTEROL

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ARTERIAL HYPERPLASIA IN THE PRESENCE OF VARIOUS FORMS OF CHOLESTEROL

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OBSERVATIONS CONCERNING THE EVOLUTION OF ATHEROSCLEROSIS IN THE RABBIT AFTER CESSATION OF CHOLESTEROL FEEDING

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Thromboatherosclerosis in aortic venous autografts: a comparative study

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EXCESS LIPID LEAKAGE: A PROPERTY OF VERY YOUNG VASCULAR ENDOTHELIUM

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