Adrenomedullin in mast cells of abdominal aortic aneurysm

OBJECTIVES: Produced by vascular walls, adrenomedullin (AM) exerts antifibrotic actions in the process of cardiovascular remodeling. The purpose of this study was to examine the pathophysiological role of AM in the development of human abdominal aortic aneurysm (AAA). METHODS AND RESULTS: Immunohistochemical analyses revealed that vascular smooth muscle cells in the media were positive for AM in the early stage of atherosclerotic aorta. Intense immunoreactivity was observed in mast cells of the outer media and adventitia of AAA, and the number of mast cells was greater (p < 0.01) in AAA than in atherosclerotic aorta without any aneurysmal change. To determine the role of AM in mast cells, we examined cultured human mast cell leukemia line-1 (HMC-1) and fibroblasts isolated from AAA patients. Cultured HMC-1 cells were found to express preproAM gene and release AM peptide into the cultured media. When assessed by collagenase-sensitive [3H]proline incorporation and procollagen type I C-peptide secretion, collagen synthesis in co-culture of HMC-1 and the fibroblasts was reduced by 10(-6) mol/L synthetic AM, while conversely, it increased following blockade of the action of endogenous AM with 10 microg/mL anti-AM monoclonal antibody. CONCLUSION: The present study suggests an anti-fibrotic role for AM released from mast cells, providing new insight into the biological actions of mast cell-derived AM in the development of AAA.     

Adventitial progenitor cells contribute to arteriosclerosis

Accumulating evidence indicates the involvement of vascular progenitor cells in the development of arteriosclerosis, including transplant arteriosclerosis, angioplasty-induced restenosis, vein graft atherosclerosis, and spontaneous atherosclerosis. Recently, it was found that the adventitia of the arterial wall contains a large number of progenitor cells, which can differentiate into smooth muscle cells in vitro and in vivo. These progenitor cells were able to migrate from the adventitia into the intima, where they accumulate to contribute to atherosclerotic lesions of vein grafts in apoE-deficient mice. Thus, these cells may be a source of smooth muscle cells and might have implications for cellular, genetic, and tissue engineering approaches to vascular disease.     

T淋巴细胞在腹主动脉瘤发病机制中的作用

腹主动脉瘤(AAAs)是一个死亡率很高的医学难题,了解AAAs的发病机制有重大意义。AAAs的一个重要特征是细胞壁中巨噬细胞、中性粒细胞和淋巴细胞广泛浸润。大量研究证实了T淋巴细胞与AAAs发病密切相关,但它们在疾病进展中的作用仍不够清晰。本文阐述了T淋巴细胞在AAAs发病机制中的可能作用,对这种目前仍缺乏有效药物干预的疾病提供有效的药物治疗策略。     

Inflammatory abdominal aortic aneurysm

A 58-years-old man, with no medical past history, was examined for abdominal pain and weight loss. An enlarged kidney could be palpated, and abdominal echography showed left hydronephrosis due to ureteral compression by abdominal aortic aneurysm. Laboratory data showed an inflammatory syndrome. CT scan suggested the diagnosis of inflammatory abdominal aortic aneurysm. The use of corticosteroids brought about the regression of the symptoms and the resolution of the ureteral obstruction, permitting aneurysmectomy and prosthesis replacement without ureterolysis. This report shows the interest of preoperative radiological diagnosis of the inflammatory character of abdominal aneurysm. For uncomplicated cases, preoperative treatment using corticosteroids could allow partial regression of the periaortic inflammation and easier surgical repair.     

Syphilitic abdominal aortic aneurysm

A case report of a syphilitic aortic aneurysm in a 37-year-old male, presenting as upper abdominal pain accompanied by a pulsatile abdominal mass, is discussed.     

腹主动脉瘤血管内修复治疗术的研究进展

腹主动脉瘤血管内修复治疗近年来不断进步,尤其肾下腹主动脉瘤血管内修复术已具有与开放性外科修补术同等的价值,本文对这一领域的研究进展进行综述如下.     

老年腹主动脉瘤的手术治疗

随着我国经济发展和人民生活水平的不断提高,人们的预期寿命不断延长,至2005年末,我国65岁及以上人口为9857万人,占总人口的7．58％,中国已经进入老龄化社会。老年主动脉疾病之一是主动脉瘤,以腹主动脉瘤（ abdominal aortic aneurysm, AAA ）为多见,此外还有主动脉夹层、假性动脉瘤和主动脉闭塞等。AAA的发生率随着年龄的增长而增长,55～60岁人群发病率约为1％,80岁以上高龄人群中约为10％,而且80岁以上高龄患者AAA较年轻患者更易破裂.老年人主动脉夹层具有症状不典型或疼痛程度略轻的特点,即撕裂样疼痛出现率偏低,胸部X线片纵隔影增宽小现率较少,全身伴随症状包括恶心、呕吐、大汗均较年轻患者出现率低,可能与老年人神经反射功能和多脏器功能减退有关。这些特点使得老年主动脉夹层易漏诊、误诊,预后不良,多死于主动脉夹层破裂。随着我国人口进入老龄化,老年AAA和主动脉夹层患者逐渐增多。要使越来越多的老年AAA和主动脉夹层患者成功进行手术治疗,这对广大血管外科医生而言将是极大挑战,以下将以AAA为例讨论老年主动脉疾病的手术治疗相关问题。     

Inverse association between the existence of coronary artery disease and progression of abdominal aortic aneurysm

ObjectivesA strong degree of co-existence between coronary artery disease (CAD) and abdominal aortic aneurysm (AAA) is widely acknowledged, however, it remains to be elucidated whether the existence of CAD is associated with an accelerated expansion rate of AAA. Also, the relationship between preoperative CAD and postoperative major adverse cardiovascular events (MACE) has not been examined in Japanese patients. The aim of this study was to investigate the deleterious effects of CAD on the progression of AAA and the onset of postoperative MACE after elective AAA repair.Methods and resultsA retrospective cohort study of 665 consecutive Japanese patients who underwent elective surgical repair for infrarenal AAA at 2 high-volume Tokyo hospitals from 2003 through 2010 was performed. Preoperative CAD was shown to be a significant determinant of postoperative MACE (HR 2.29; 95%CI, 1.12–4.66; p = 0.02). In the analysis of 510 patients for whom there were at least 2 follow-up CT scans of the size of their AAA before repair, the existence of CAD was shown to be inversely associated with the accelerated expansion rate of AAA.ConclusionThis study on the patients undergone elective repair for infrarenal AAA identified an inverse association between the existence of CAD and progression of AAA as well as the significant impact of preoperative CAD on the occurrence of postoperative MACE after elective AAA repair.