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Aim: To investigate the role of pentraxin 3 (PTX3) in atherosclerotic disease progression and plaque destabilization, as well as in coronary restenosis after directional coronary atherectomy (DCA)., Materials and Methods: PTX3 contents of early and advanced atherosclerotic lesions of the aorta obtained at autopsy were determined by ELISA and Western blot. Also, coronary plaques of patients with acute coronary syndrome (ACS) or stable angina pectoris (SAP) obtained by DCA were analyzed by immunohistochemistry for PTX3. The effects of PTX3 on smooth muscle cells (SMCs) and thrombogenesis were investigated with cultured human coronary artery SMCs and a flow chamber system, respectively., Results: Advanced atherosclerotic lesions contained a significantly larger amount of PTX3 than early lesions (ELISA: 9.96 ± 2.77 ng/100 mg tissue, n = 8 vs 0.24 ± 0.18 ng/100 mg tissue, n = 6, P = 0.0097). Also, ACS plaques contained a significantly larger amount of PTX3 than SAP plaques (PTX3 immunohistochemistry-positive area percentage: 2.88 ± 0.53 %, n = 22 vs 0.67 ± 0.27 %, n = 23, P = 0.0009). Curiously, the patients who would remain free of post-DCA restenosis (n = 19) had plaques with a significantly higher PTX3 immunohistochemistry-positive area percentage than those who would develop restenosis (n = 12) (2.32 ± 0.49 % vs 0.49 ± 0.17 %, P = 0.002). In the mechanistic part of the study, PTX3 inhibited SMC proliferation and migration. PTX3 also inhibited platelet thrombus formation in the condition simulating arterial blood flow., Conclusions: PTX3 is increased in advanced (vs early) atherosclerotic lesions and unstable (vs stable) coronary plaques. The inhibitory effects of PTX3 on SMCs and thrombogenesis suggest that intraplaque PTX3 might have atheroprotective effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Coronary high-signal-intensity plaques (HIPs) detected by T 1 -weighted magnetic resonance imaging are associated with future cardiovascular events. This study aimed to identify pathological findings reflecting HIPs in coronary arteries obtained from autopsy cases. Formalin-fixed hearts were imaged with noncontrast T 1 -weighted imaging with a 1.5-T magnetic resonance system. We defined HIPs or non-HIPs as a coronary plaque to myocardial signal intensity ratio (PMR) of ≥1.4 or <1.4, respectively. We found HIPs in 4 of 37 (10.8%) hearts and analyzed 7 hearts in detail. The corresponding sections to HIPs (n=11) or non-HIPs (n=25) were histologically and immunohistochemically analyzed. We calculated the T 1 relaxation time of human venous blood in vitro. Plaque and necrotic core areas, and the frequency of intraplaque hemorrhage in HIPs were significantly larger/higher than those in non-HIPs. HIPs were immunopositive for CD68 (11/11), glycophorin A (10/11), and fibrin (11/11). Glycophorin-A-, matrix metalloprotease 9 (MMP9)-, and tissue factor-immunopositive areas were larger in HIPs than in non-HIPs. The PMR was positively correlated with glycophorin-A-, fibrin-, MMP9-, and tissue factor-immunopositive areas. Blood coagulation shortened the T 1 relaxation time of the blood and plasma, and the T 1 relaxation times in coagulated whole blood and erythrocyte-rich blood were significantly shorter than those in plasma. Coronary HIPs may reflect intraplaque hemorrhage and may be a novel marker for plaque instability and thrombogenic potential., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In order to examine their suitability for studies on coronary atherosclerosis, we evaluated the features of coronary atherosclerotic plaques in myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, a spontaneous animal model for coronary atherosclerosis and myocardial infarction. Coronary segments of the hearts of 187 WHHLMI rabbits (10-29 months old) were sectioned serially and stained histopathologically and immunohistologically. Progression of coronary lesions was prominent in rabbits that had died suddenly. The degree of coronary lesions of females was higher than that of males. Various types of atherosclerotic lesions were observed in the coronary arteries, such as plaques with a large lipid core covered by a thin fibrous cap, fatty streaks, early and advanced fibroatheromas, fibrous lesions, and advanced lesions with calcium accumulation and the vasa vasorum. In rabbits that had died suddenly, the frequencies of fibroatheromas or advanced lesions were higher than those of rabbits euthanized. Matrix metalloproteinase (MMP)-positive macrophages were detected in gaps among endothelial cells at the plaque surface, beneath the fibrous cap of thin-capped fibroatheromas, and at the bottom of the intimal plaques in which the tunica media was attenuated. Immunohistological results suggest that MMP-positive macrophages are involved in the initiation, progression, and destabilization of coronary plaques, in addition to vascular remodeling, even in WHHLMI rabbits. In conclusion, coronary lesions in WHHLMI rabbits resemble human atherosclerotic lesions, and thus, the WHHLMI rabbit is a suitable animal model for studies on human coronary plaques.

Atherosclerotic lesions represent a hypoxic milieu. However, the significance of this milieu in atherothrombosis has not been established. We aimed to assess the hypothesis that vascular wall hypoxia promotes arterial thrombus formation. We examined the relation between vascular wall hypoxia and arterial thrombus formation using a rabbit model in which arterial thrombosis was induced by 0.5 %-cholesterol diet and repeated balloon injury of femoral arteries. Vascular wall hypoxia was immunohistochemically detected by pimonidazole hydrochloride, a hypoxia marker. Rabbit neointima and THP-1 macrophages were cultured to analyse prothrombotic factor expression under hypoxic conditions (1 % O2). Prothrombotic factor expression and nuclear localisation of hypoxia-inducible factor (HIF)-1α and nuclear factor-kappa B (NF-κB) p65 were immunohistochemically assessed using human coronary atherectomy plaques. Hypoxic areas were localised in the macrophage-rich deep portion of rabbit neointima and positively correlated with the number of nuclei immunopositive for HIF-1α and NF-κB p65, and tissue factor (TF) expression. Immunopositive areas for glycoprotein IIb/IIIa and fibrin in thrombi were significantly correlated with hypoxic areas in arteries. TF and plasminogen activator inhibitor-1 (PAI-1) expression was increased in neointimal tissues and/or macrophages cultured under hypoxia, and both were suppressed by inhibitors of either HIF-1 or NF-κB. In human coronary plaques, the number of HIF-1α-immunopositive nuclei was positively correlated with that of NF-κB-immunopositive nuclei and TF-immunopositive and PAI-1-immunopositive area, and it was significantly higher in thrombotic plaques. Vascular wall hypoxia augments the thrombogenic potential of atherosclerotic plaque and thrombus formation on plaques via prothrombotic factor upregulation.

Background: Atherosclerotic plaque thrombogenicity is a critical factor that affects thrombus formation and the onset of acute myocardial infarction (AMI). The aim of this study was to identify the vascular factors involved in thrombus formation and AMI onset., Methods and results: Culprit lesions in 40 coronary arteries with thrombi at autopsy after lethal AMI and non-cardiac death (asymptomatic plaque disruption) were analyzed on histology. Thrombus size, ratio of thrombus to lumen area, length of plaque disruption, and immunopositive areas for tissue factor (TF) and hexokinase (HK)-II were significantly larger in coronary arteries with AMI than with asymptomatic plaque disruption. The size of coronary thrombus positively correlated with the length of plaque disruption (r=0.80) and with immunopositive areas for TF (r=0.38) and HK-II (r=0.40). Because both M1 and M2 macrophages express TF and HK-II in symptomatic plaques, we assessed TF and HK-II expression in M1- and M2-polarized macrophages. The expression of TF was increased and that of HK-II was decreased in M2-, compared with M1-polarized THP-1 macrophages. Inhibiting glycolysis enhanced TF expression in the macrophages partly via hypoxia inducible factor-1α., Conclusions: The degree of plaque disruption and expression of TF and HK-II appear to be important vascular factors for AMI onset, and polarized macrophages make a distinct contribution to thrombogenicity and glucose metabolism.

Objective: Apolipoprotein (apo) A-II is the second major apo of high-density lipoproteins, yet its pathophysiological roles in the development of atherosclerosis remain unknown. We aimed to examine whether apo A-II plays any role in atherogenesis and, if so, to elucidate the mechanism involved., Methods and Results: We compared the susceptibility of human apo A-II transgenic (Tg) rabbits to cholesterol diet-induced atherosclerosis with non-Tg littermate rabbits. Tg rabbits developed significantly less aortic and coronary atherosclerosis than their non-Tg littermates, while total plasma cholesterol levels were similar. Atherosclerotic lesions of Tg rabbits were characterized by reduced macrophages and smooth muscle cells, and apo A-II immunoreactive proteins were frequently detected in the lesions. Tg rabbits exhibited low levels of plasma C-reactive protein and blood leukocytes compared with non-Tg rabbits, and high-density lipoproteins of Tg rabbit plasma exerted stronger cholesterol efflux activity and inhibitory effects on the inflammatory cytokine expression by macrophages in vitro than high-density lipoproteins isolated from non-Tg rabbits. In addition, β-very-low-density lipoproteins of Tg rabbits were less sensitive to copper-induced oxidation than β-very-low-density lipoproteins of non-Tg rabbits., Conclusions: These results suggest that enrichment of apo A-II in high-density lipoprotein particles has atheroprotective effects and apo A-II may become a target for the treatment of atherosclerosis.

Background: Ultrasound-determined carotid intima-media thickness (IMT) is widely used as an indicator of generalized atherosclerotic burden, but there are limited autopsy findings in support of the association, directly., Methods: We performed an autopsy analysis (n = 111, mean 68.8 years; 65.0% men; 86% non-cardiovascular disease death) to examine the associations of microscopy-determined carotid IMT including plaque thickness with the severity of atherosclerosis in the generalized arteries., Results: Microscopy-determined carotid IMT was associated with the extent of intima/media layer ratio of the vasculature, a marker of atherosclerosis, in each structure examined, i.e., coronary artery, cerebrovasculature, thoracic aorta, abdominal aorta, and iliac artery (R = 0.31-0.42; all P < 0.01). The prevalence of a necrotic core in the coronary artery, cerebrovasculature, thoracic aorta, abdominal aorta, and iliac artery increased in accordance with increasing microscopy-determined carotid IMT (all P < 0.05)., Conclusion: Our autopsy analysis confirms the validity of carotid IMT including plaque thickness as an indicator of generalized atherosclerosis., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Aim: To understand the differences between histopathological characteristics related to PTX3 (pentraxin 3) and CRP (C-reactive protein) in coronary atherosclerotic plaques., Methods and Results: To assess the localization of PTX3 and CRP in coronary plaque, immunohistochemistry was performed using 157 coronary artery specimens from 45 autopsied cases. Overall, immunoreactivity to CRP was more intense than that to PTX3 in lipid rich plaque; however, PTX3 was notably abundant in areas of intraplaque hemorrhage, in which CRP was quite sparse. On quantitative analysis, complicated plaques showed more immunopositive area of PTX3 than fibroatheroma, but with CRP, this trend disappeared. In addition, we examined the phenotype of macrophages in PTX3- and CRP-rich areas using CD163 staining (M2 macrophages). Consequently, these areas were differently characterized by the accumulation of macrophages with high and low magnitude of CD163 positivity, respectively. Next, we immunohistochemically investigated relationships among PTX3, CRP, histological components and clinical presentation in 73 coronary atherectomy specimens obtained from 35 and 38 patients with unstable (UAP) and stable angina pectoris (SAP), respectively. Both PTX3 and CRP were more intense in culprit plaques from patients with UAP than with SAP, and they significantly correlated with CD68 (pan macrophage)-positive areas; however, there was no correlation between PTX3 and CRP., Conclusion: Although PTX3 and CRP were more enhanced in unstable than in stable coronary plaques, their distribution distinctly differed, suggesting that they play distinct biological roles in unstable plaques.

Objectives: We sought to assess the association between inflammation in pericardial fat (PF) and coronary artery disease (CAD) by pathological examination and clinical evaluation with cardiac computed tomography (CT)., Background: Inflammation of adipose tissue is involved in cardio-metabolic disorders and shows high density in CT., Methods: We quantified, by immunohistochemical means, the PF inflammation in 39 autopsy cases by counting leukocyte common antigen (LCA)-positive cells. We then measured the CT density of PF in 39 patients with acute coronary syndromes and 69 patients suspected of CAD., Results: Pericoronary PF had significantly more LCA-positive cells in CAD autopsy cases (n=21) than non-CAD cases (n=18) (44 ± 21 vs. 24 ± 22 cells/mm(2), p=0.006). The CT density of PF around culprit lesions was significantly higher than non-culprit lesions in patients with acute coronary syndromes (-72 ± 11 vs. -82 ± 14 HU, p=0.002), which may reflect PF inflammation. Among patients suspected of CAD, the pericardial CT density gradient (PDG; difference in CT density between pericoronary PF and PF apart from coronary arteries) was significantly greater in CAD patients (n=30) than non-CAD patients (n=39) (22 ± 16 vs. 16 ± 10 HU, p=0.046). Multiple logistic regression analysis demonstrated that the PF inflammation index (PFI; PDG × PF volume, which could be the integrated index of inflammatory activity and abundance of PF) was significantly associated with the presence of CAD (odds ratio [95% confidence interval]; 1.234 [1.012-1.503] per 1000 HU cm(3), p=0.037) independent of other metabolic risk factors such as hypertension, dyslipidemia, and diabetes., Conclusions: Active inflammation in PF correlates with CAD. PF inflammation may be involved in pathogenesis of CAD., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: The endoplasmic reticulum (ER) responds to various stresses by upregulation of ER chaperones, but prolonged ER stress eventually causes apoptosis. Although apoptosis is considered to be essential for the progression and rupture of atherosclerotic plaques, the influence of ER stress and apoptosis on rupture of unstable coronary plaques remains unclear., Methods and Results: Coronary artery segments were obtained at autopsy from 71 patients, and atherectomy specimens were obtained from 40 patients. Smooth muscle cells and macrophages in the fibrous caps of thin-cap atheroma and ruptured plaques, but not in the fibrous caps of thick-cap atheroma and fibrous plaques, showed a marked increase of ER chaperone expression and apoptotic cells. ER chaperones also showed higher expression in atherectomy specimens from patients with unstable angina pectoris than in specimens from those with stable angina. Expression of 7-ketocholesterol was increased in the fibrous caps of thin-cap atheroma compared with thick-cap atheroma. Treatment of cultured coronary artery smooth muscle cells or THP-1 cells with 7-ketocholesterol induced upregulation of ER chaperones and apoptosis, whereas these changes were prevented by antioxidants. We also investigated possible signaling pathways for ER-initiated apoptosis and found that the CHOP (a transcription factor induced by ER stress)-dependent pathway was activated in unstable plaques. In addition, knockdown of CHOP expression by small interfering RNA decreased ER stress-dependent death of cultured coronary artery smooth muscle cells and THP-1 cells., Conclusions: Increased ER stress occurs in unstable plaques. Our findings suggest that ER stress-induced apoptosis of smooth muscle cells and macrophages may contribute to plaque vulnerability.

Aims: The present study investigates the expression and localization of interleukin (IL)-10, an important anti-inflammatory cytokine, in atherectomy specimens from patients with stable and unstable angina., Methods and Results: Twenty-two patients with stable angina and 21 with unstable angina who underwent directional coronary atherectomy for de novo lesions were studied. The atherectomy specimens were morphologically assessed and immunohistochemically stained with antibodies for IL-10, macrophages, smooth muscle cells, and endothelial cells. The localization and immunopositive areas were evaluated using an image analysing system. Immunoreactivity for IL-10 was detected in coronary plaques, especially in macrophages. Immunopositive areas of macrophages and IL-10, as well as the incidence of thrombus formation, were significantly greater in specimens from patients with unstable angina than in those from patients with stable angina (macrophages, P<0.001; IL-10, P<0.05; thrombus formation, P<0.05; respectively). Even after adjustment, IL-10 expression and the incidence of thrombus formation were significantly greater in the unstable angina group (P<0.05, each). The immunoreactivities for smooth muscle cells and endothelial cells did not differ between the two groups., Conclusion: IL-10 was more frequently expressed in specimens from patients with unstable angina. This finding might contribute to a better understanding of plaque instability.

Objective: To determine the proportion of platelets and fibrin in coronary thrombi., Design: Immunohistochemical and morphometric means to examine the coronary arteries of 31 patients who died of acute myocardial infarction., Results: Fresh thrombi were detected in the feeding arteries of infarction areas in 23 cases (74%) and were associated with plaque rupture in 18 (78%) and plaque erosion in 5 (22%). An immunohistochemical study showed that the thrombi consisted of a mixture of fibrin and platelets as well as some other types of blood cells. The fibrin and platelet positive areas in the thrombi associated with plaque rupture accounted for 74 (19)% and 35 (20)% (p < 0.01) and those associated with erosion accounted for 51 (6)% and 70 (21)%, respectively, of the total areas. Areas of positive immunoreactivity for tissue factor and C reactive protein were also significantly greater in ruptured than in eroded plaques., Conclusion: These results indicate that the proportions of fibrin and of platelets differ in coronary thrombi on ruptured and eroded plaques. Higher proportions of tissue factor and C reactive protein contribute more significantly to thrombus formation on plaque rupture than on plaque erosion.

To determine whether the inflammatory response is equally involved in the pathogenesis of restenosis after coronary stenting and directional coronary atherectomy, we assessed restenotic lesions with immunohistochemical methods. Levels of C-reactive protein and macrophages were greater in patients with in-stent restenosis than in those with restenosis after directional coronary atherectomy. This suggests that the inflammatory response is more involved in the pathogenesis of in-stent restenosis than in restenosis after directional coronary atherectomy.

C-reactive protein (CRP) mRNA was detected in coronary plaque. Plasma CRP levels across the coronary circulation were increased much more in patients with unstable angina pectoris and somewhat more in those with stable angina pectoris compared with controls whose coronary arteries were angiographically normal. Thus, CRP within coronary plaque might contribute to increased plasma CRP levels across coronary circulation, particularly among patients with unstable angina pectoris.

We histologically examined the coronary arteries of 52 autopsied cases of the youths (3 to 39 years of age, mean 28.5 years) in Kyushu island, Japan, without clinical events of coronary artery diseases. The coronary artery specimens were taken from the proximal portions of the right coronary artery (Seg. 1), the left anterior descending artery (Seg. 6), and the macroscopically most stenotic region (ST). Atherosclerotic lesions were histologically classified into four types: concentric fibrous, eccentric fibrous, concentric lipid rich, or eccentric lipid-rich type. The degrees of stenosis (< 25%, 25-50%, 50 75%, > 75%) were morphometrically evaluated. The majority of coronary arteries with under 50% stenosis were of the concentric fibrous type. Lipid-rich types of coronary atherosclerosis increased in the coronary arteries with over 50% stenosis and were observed in the Seg. 6 and ST, while 70% of Seg. 1 lesions with over 50% stenosis were of a fibrous type. Serum cholesterol levels of patients with a lipid rich type of coronary atherosclerosis were significantly higher than those with a fibrous type. These results suggested that the early stage of coronary atherosclerosis in Japanese youths is mainly of a concentric fibrous type, which later develops to a lipid rich type. Hypercholesterolemia would promote the progression of atherosclerosis.