Yuichiro Sato

Localization and activity of tissue factor in human aortic atherosclerotic lesions

Tissue factor (TF) is a transmembrane protein that serves as the major initiator of the blood coagulation cascade. The overexpression of TF antigen and mRNA has previously been reported in advanced atherosclerotic lesions. Recently TF procoagulant activity has also been identified in these lesions. However, localization and activity of TF in various stages of atherosclerosis have not yet been reported. We studied TF localization and its activity in three stages of the human atherosclerotic lesions (diffuse intimal thickening, fatty streak, and atheromatous plaque). The thoracic aortas were obtained from 23 autopsy cases and were examined immunohistochemically using an anti-human TF polyclonal antibody and biotinylated factor VIIa (FVIIa) as a probe to test the FVIIa-binding ability of TF. In addition, the TF-mediated activation of factor X (FX) was quantitatively assessed using a chromogenic assay. In lesions of the diffuse intimal thickening and the fatty streak, almost all of intimal smooth muscle cells (SMCs), macrophages, and endothelial cells were positive for TF. In the atheromatous plaques, TF antigen was detected extensively in the extracellular matrix as well as in the intimal cells. TF in all stages of atherosclerotic lesions had the ability to bind biotinylated FVIIa. TF activity was detected in each lesion and was more prominent in fatty streaks and atheromatous plaques than in the diffuse intimal thickening. These results indicate that active TF is expressed in the early stage of atherosclerotic lesions as well as in the advanced stage, and it contributes to the thrombotic property of human atherosclerotic lesions.

Protease-activated receptor 2 (PAR2) mediates vascular smooth muscle cell migration induced by tissue factor/factor VIIa complex

UNLABELLED Protease-activated receptor 2 (PAR2) is one of G-protein-coupled receptors able to be activated by trypsin and coagulation factor VIIa. We previously reported that tissue factor/factor VIIa (TF/FVIIa) complex was a strong chemotactic factor for cultured vascular smooth muscle cells (SMCs). The migratory response was dependent on a catalytic activity of FVIIa, and did not involve factor Xa and thrombin generation. In this study, we examined TF/FVIIa-induced SMC migration. METHODS The contribution of PAR2 to TF/FVIIa-induced vascular SMC migration was investigated using a modified Boydens chamber method, and the distribution of PARs in the human coronary arteries and cultured SMCs was also examined. RESULTS Trypsin and PAR2-activating peptide (AP; SLIGKV) stimulated SMC migration in a dose-dependent manner, of which abilities were comparable to those of TF/FVIIa complex and platelet-derived growth factor-BB, but PAR1-AP (TFLLR or SFLLR) or PAR4-AP (AYPGOV) did not elicit the migration. The antisera against PAR2-AP significantly inhibited TF/FVIIa-induced SMC migration, but that of PAR1-AP did not. In immunostaining, both intimal SMCs of the human coronary arteries and cultured SMCs showed positive reaction for PAR2-AP. CONCLUSION These results suggest that PAR2 in SMCs plays a crucial role in the cell migration induced by TF/FVIIa complex.

Large cell neuroendocrine carcinoma of the uterine cervix: a clinicopathological study of six cases.

&NA; Six cases of cervical large cell neuroendocrine carcinomas (LCNEC) were found among 972 patients (0.6%) with invasive cervical carcinoma. The patients, who were from 27 to 51 (mean 38) years of age, presented with vaginal bleeding or an abnormal Papanicolaou smear. Five tumors were stage Ib and one was IIa. All patients underwent radical hysterectomy and received adjuvant chemotherapy and pelvic radiotherapy. Four patients died of tumor 6 to 19 months (mean 14 months) postoperatively. On histologic examination, the tumor cells were arranged in an organoid growth pattern and were larger than those of typical small cell carcinoma. Glandular differentiation was present in one case. Mitotic figures ranged from 15 to 45 (mean 29) per 10 high‐power fields. Prominent vascular invasion and necrosis was seen in all of the tumors. Each tumor was immunoreactive for chromogranin A and/or synaptophysin. The results of this study confirm the aggressive nature of cervical LCNECs. The recognition of LCNECs is necessary to establish the most effective treatment for these aggressive tumors.

Proportion of fibrin and platelets differs in thrombi on ruptured and eroded coronary atherosclerotic plaques in humans

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.

Novel distribution of adrenomedullin-immunoreactive cells in human tissues

Abstract Adrenomedullin (AM) is a novel hypotensive and vasodilator peptide. We previously examined the localization of AM in human, rat, and porcine tissues using a polyclonal antibody against synthetic human AM[40–52]. We demonstrated that AM is widely distributed in the endocrine and neuroendocrine systems, but not in the heart, kidney, or blood vessels, although high levels of AM mRNA were detected in the latter tissues. In this study, we further investigated the distribution of AM by using two newly developed monoclonal antibodies against synthetic human AM peptides, [12–25] and [46–52]. AM immunoreactivity was observed in cardiac myocytes, vascular smooth muscle cells, endothelial cells, and renal distal and collecting tubules. In addition, AM-immunoreactive (IR) cells were found in mucosal and glandular epithelia of the digestive, respiratory, and reproductive systems, as well as the endocrine and neuroendocrine systems. These findings indicate that AM-IR cells are more widely distributed in human tissues and suggest that AM might play multiple biological roles in humans.

Pericardial fat inflammation correlates with coronary artery disease

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.

Usefulness of carotid intima-media thickness measurement as an indicator of generalized atherosclerosis: Findings from autopsy analysis

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.

PULMONARY TUMOR THROMBOTIC MICROANGIOPATHY

Pulmonary tumor thrombotic microangiopathy (PTTM) is characterized by widespread fibrocellular intimal proliferation of the small pulmonary arteries and arterioles in patients with metastatic Carcinoma. Microscopic pulmonary tumor emboll have frequently occurred in patients with malignant tumors; however, few cases of PTTM have been reported. A rare case of a patient with gastric adenocarcinoma who presented with acute dyspnea and lethal respiratory failure is described. Histologically, diffuse fibromuscular intimal thickening cauring luminal stenosis and obstruction but containing rather few cancer cells was observed in the small pulmonary arteries and arterioles. These findings were consistent with PTTM. Atthough PTTM is a rare phenomenon, PTTM should be considered in the differential diagnosis of acute dyspnea or pulmonary hypertension in patients with carcinoma.

Incidence of asymptomatic coronary thrombosis and plaque disruption: Comparison of non-cardiac and cardiac deaths among autopsy cases

BACKGROUND Autopsy studies have revealed a high incidence of thrombus formation in patients who died of acute myocardial infarction (AMI) or sudden coronary death. However, the incidence of thrombus formation and plaque disruption in patients with non-cardiac death (NCD) remains unclear. METHODS To evaluate the incidence and morphological characteristics of thrombi and plaque disruption in patients with NCD, we examined 102 hearts from NCD autopsy cases and 19 from those who had died of AMI. RESULTS We found fresh coronary thrombi in 10 cases with NCD and in 14 with AMI (10% vs. 75%, p < 0.001). Seven and three thrombi were associated with plaque erosion and rupture, respectively among the NCD cases. The incidence of plaque rupture was significantly higher in AMI than in NCD (54% vs. 3%, p < 0.001). The size of coronary thrombi in NCD cases was small and the luminal areas were not significantly affected. Plaques beneath thrombi in NCD had a smaller lipid core and a thicker fibrous cap than those in AMI. Among risk factors for cardiovascular events, hypertension and diabetes mellitus were significantly associated with the incidence of thrombosis in patients with NCD. CONCLUSION Coronary thrombosis is a frequent complication in patients with NCD. These small thrombi might not be associated with the onset of clinical events, but with plaque progression in atherosclerosis.

Plasma Pentraxin 3, but not High-sensitivity C-reactive Protein, is a Useful Inflammatory Biomarker for Predicting Cognitive Impairment in Elderly Hypertensive Patients

BACKGROUND Due to the increasing longevity of human populations worldwide, there is need of a useful biomarker for the early detection of cognitive impairment in elderly persons. Both high blood pressure (BP) and inflammatory processes have been reported to be involved in cognitive impairment via cerebrovascular atherosclerosis or neuronal cell damage. METHODS In this cross-sectional study of 210 ambulatory elderly hypertensive patients without clinically evident dementia (mean age: 74 years; 44% men), we measured 24-hour BP, circulatory pentraxin 3 (PTX3) and high-sensitivity C-reactive protein (hs-CRP) levels, and cognitive function (Mini-Mental State Examination [MMSE]). RESULTS A high plasma PTX3 level was observed in lean subjects, especially in those whose current body weight was lower than that measured 5 years earlier, whereas a high hs-CRP level was associated with obesity (all p < .05). Both PTX3 and hs-CRP levels were significantly associated with the MMSE score (r = -.248, p<0.001 and r = -.153, p<0.05, respectively); however, in multiple regression analysis, the PTX3 level, but not the hs-CRP level, was inversely associated with the MMSE score independently of patient demographics, glucose and lipid metabolic parameters, 24-hour systolic BP (SBP) level, and the atherosclerotic burden (all p < .05). Moreover, there was a significant interaction between the PTX3 and 24-hour SBP levels in the determinants of MMSE score (p < .05). CONCLUSIONS A high plasma PTX3 level in elderly hypertensive patients, particularly in those with a high 24-hour BP level, could be a significant predictor of cognitive impairment. A high PTX3 level may be a marker of frailty in elderly hypertensive patients.