Role of oral bacterial flora in calcific aortic stenosis: an animal model

BACKGROUND: Calcific aortic stenosis is a major public health problem in the United States. The mechanism of calcification remains unclear. The hypothesis that low grade chronic or recurrent bacterial endocarditis with specific calcifiable bacteria is a cause of calcification of the aortic valves was investigated using an animal model. Such bacteria are typically present as part of the normal human oral flora. METHODS: Forty New Zealand white rabbits were divided into four groups: group 1, control (1 ml of normal saline); group 2, Corynebacterium matruchotti 100,000 colonies; group 3, Streptococcus sanguis II 10 colonies; and group 4, C matruchotti 100,000 colonies plus S sanguis II 10 colonies. Animals were inoculated with bacteria through a flexible catheter placed through the aortic valve through a right carotid cut down. Inoculations were repeated every 3 days the first 2 weeks and then twice a week thereafter. At postmortem examination the aortic valves were harvested, embedded in paraffin, and stained with von Kossa stain. They were also examined by scanning and transmission electron micrography. RESULTS: Group 4 had 93.3% large calcifications (confluent calcium densities that are easily recognized with minimal magnification) and 6.6% small microcalcifications (dustlike microscopic particles requiring a compound microscope to appreciate) of the aortic valves. Group 3 exhibited large calcification in 20% and small in 40% of the aortic valves. Group 1 and group 2 had no evidence of calcification. CONCLUSIONS: These results suggest that recurrent low-grade endocarditis from calcifying oral bacteria, particularly when occurring with synergistic strains, may be one cause of calcific aortic stenosis.     

基质金属蛋白酶-9在腹主动脉瘤体组织中的表达及其临床意义

目的 通过检测基质金属蛋白酶-9（MMP-9）在人腹主动脉瘤（AAAs）组织中的定位表达，探讨MMP-9在腹主动脉瘤发病机制中的作用及临床意义。方法 应用免疫组织化学技术，检测了MMP-9在20例AAAs瘤体组织中的定位表达，并与15例动脉硬化闭塞性疾病（AODs）的病变管壁及10例正常动脉管壁组织中的MMP-9组织学表达进行对照研究。结果 AAAs动脉壁中富含大量MMP-9颗粒，MMP-9阳性表达率达95．0％（19／20）；正常动脉管壁组织未检测到MMP-9的表达；AODs病变血管壁内可见散在分布的MMP-9阳性颗粒，MMP-9阳性表达率为26．7％（4／15）。与AODs和正常动脉管壁相比较，MMP-9在AAAs瘤体组织中的表达差异具有意义（P〈0．01）。结论 腹主动脉瘤体组织中MMP-9的高表达，促进主动脉中层细胞外基质崩解进而导致动脉弹性下降、动脉扩张及进一步的瘤体形成，在AAAs的发病机制中具有重要作用。     

基质金属蛋白酶9在胸主动脉瘤和胸主动脉夹层中的表达

目的 观察基质金属蛋白酶(MMP)-9在DebakeyI型胸主动脉夹层(TAD)和胸主动脉瘤(TAA)中的表达,探讨其在TAD和TAA中的作用.方法 苏木素-伊红(HE)染色、铁苏木素染色、TUNEL染色、免疫组织化学染色分别观察11例TAD和10例TAA的病理特征、弹力纤维断裂、管壁细胞凋亡、MMP-9在动脉管壁中的表达和定位,并分析MMP-9表达与各项临床参数的关系.结果 MMP-9在TAD和TAA中高表达(P<0.05),主要位于中外膜平滑肌细胞和炎性细胞,MMP-9表达与主动脉直径显著相关(P<0.05).结论 MMP-9在TAD和TAA中高表达,中外膜平滑肌细胞和炎性细胞是其主要表达细胞;MMP-9可能通过弹力板层的破坏来影响管壁重构过程.     

Relationship of airway wall thickening to an imbalance between matrix metalloproteinase-9 and its inhibitor in asthma

BACKGROUND: The balance between matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) may be critical in extracellular matrix remodelling, a characteristic of asthmatic airways. An excess of TIMP-1 over MMP-9 has been associated with chronic airflow obstruction but the mechanisms underlying this association remain unknown. Recent computed tomographic (CT) studies indicate that airway wall thickening is associated with chronic airflow obstruction. METHODS: Sputum levels of MMP-9, TIMP-1, and their molar ratio were examined in 26 patients with stable asthma and their relationship with pulmonary function and airway wall thickness, assessed by a validated CT technique which measured wall area corrected by body surface area (WA/BSA), the ratio of WA to outer wall area (WA%), and the absolute wall thickness corrected by radicalBSA of a segmental bronchus (T/ radicalBSA), was examined. RESULTS: Sputum MMP-9 levels were inversely correlated with WA% and TIMP-1 levels were positively correlated with WA/BSA and T/ radicalBSA. The MMP-9/TIMP-1 molar ratio was inversely correlated with WA% and T/ radicalBSA and positively correlated with post-bronchodilator values of mid-forced expiratory flow and maximum expiratory flow at the quartile of lung volume. CONCLUSION: Excess TIMP-1 may have a pathogenetic role in airway wall thickening in asthmatic patients which may result in chronic airflow obstruction.     

Gender differences in rat aortic smooth muscle cell matrix metalloproteinase-9

BACKGROUND: A predilection exists for men to develop abdominal aortic aneurysms (AAAs), but the reasons for this gender predisposition are not known. Matrix metalloproteinase-9 (MMP-9) has been implicated in both human and experimental AAAs. This investigation tested the hypothesis that male and female gender differences exist in the production of MMP-9 by rat aortic smooth muscle cells (RASMCs). STUDY DESIGN: In the first set of experiments, cultured male and female RASMCs were stimulated with interleukin-1 beta (IL-1beta) at 2 ng/mL. Messenger RNA was extracted from the RASMCs and gene expression of MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1), an MMP-9 inhibitor, was measured by quantitative real-time polymerase chain reaction. Cell culture media were collected for measurement of MMP-9 protein levels and MMP-9 activity by Western blotting and gelatin zymography, respectively. In the second set of experiments, male RASMCs were treated with 17-beta-estradiol (10(-10) to 10(-6) mol/L) and MMP-9 activity was measured. In the third set of experiments, male rats were pretreated with estradiol, and MMP-9 activity was measured in the media from explanted aortas. RESULTS: MMP-9 gene expression was 10-fold higher in male versus female RASMCs (p=0.003). MMP-9 protein levels (p=0.005) and gelatinolytic activities (p=0.01) were also greater in male than female RASMCs. TIMP-1 expression was fourfold higher in male versus female RASMCs (p<0.001). Estradiol-treated male RASMCs did not exhibit a decrease in MMP-9 activity. But aortic explants from male rats pretreated with 17-beta-estradiol had 60% less MMP-9 activity than explants from male controls (p=0.03). CONCLUSIONS: MMP-9 and TIMP-1 are greater in male than in female RASMCs. These findings support the tenet that gender-related differences in MMP-9 may contribute to AAA formation.     

Surgery for calcific aortic root stenosis in homozygous familial hypercholesterolemia.

A 35-year-old female with homozygous familial hyperlipidemia (IIa) was referred to our hospital for an operation against supravalvular and valvular aortic stenosis. She had been treated with low-density lipoprotein apheresis for 20 years, and total cholesterol ranged between 200 and 400 mg/dl under this treatment. She had undergone percutaneous coronary intervention for ostial stenosis of the right coronary artery three times since the age of 19. Unenhanced three-dimensional computed tomography showed supravalvular stenosis, funnelling and heavily calcified aorta. An operation was performed under deep hypothermic circulatory arrest without aortic cross clamping. After the ascending aorta had been replaced with a one-branched vascular graft, arterial perfusion was resumed. The stenosed ascending aorta was resected at the sinotubular junction. Because the aortic root was still extremely small, the noncoronary sinus and the commissure between left and right coronary cusp were incised, and the aortic root was enlarged with linguiform vascular-graft patches. A 21-mm mechanical valve was implanted. The postoperative course was uneventful.     

HMG-CoA reductase inhibitors reduce matrix metalloproteinase-9 activity in human varicose veins

Matrix metalloproteinases (MMPs) have been implicated in tissue degradation in varicose veins. The aim of this study was to investigate the effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) on the activity of MMPs in varicose veins. MMP-9 was present at significantly higher levels in varicose veins than in controls and was localized mainly in smooth muscle cells at the tunica media, where marked degradation of the extracellular matrix was observed. Both simvastatin and pravastatin strikingly suppressed MMP-9 activity in ex vivo culture of varicose veins. Simvastatin suppressed MMP-9 at both the mRNA and protein levels as well as at the urokinase-type plasminogen activator protein level, resulting in the dramatic suppression of MMP-9 activity induced by tumor necrosis factor-alpha. Therefore, statins suppress MMP-9 activity by multiple mechanisms in varicose veins, suggesting they may have clinical potential for the treatment of this disease.     

Role of transvalvular gradient in outcome from valve replacement for aortic stenosis

BACKGROUND: Despite limitations the transvalvular gradient (TVG) still is commonly used in aortic stenosis when patients are referred for aortic valve replacement. We wished to ascertain if it had a role in predicting outcome from valve replacement rather than as an indicator of severity, specifically investigating if the TVG affected renal dysfunction, hospital stay, and medium-term survival after valve replacement. METHODS: Six hundred and twenty-three consecutive patients who had aortic valve replacement were identified and 211 of these patients were isolated as first time replacement for aortic stenosis that formed the final study group, and were followed up for up to 48 months. Variables significant (p < 0.05) on univariate analysis were included in the logistic regression multivariate analysis (renal dysfunction, prolonged hospital stay) or Cox proportional hazard regression model (medium-term mortality). RESULTS: A significant association was present between TVG and age (p = 0.001). Multivariate analysis demonstrated angina greater than or equal to grade 3 Canadian Cardiovascular Society (CCS 3; p = 0.014) and having nonelective surgery (p < 0.001) to be independent predictors of renal dysfunction. Angina greater than or equal to CCS 3 (p = 0.013) was the only independent predictor of prolonged hospital stay. Independent predictors of medium-term mortality on multivariate analysis were age (p = 0.043) and having a size 19 valve prosthesis (p = 0.015). CONCLUSIONS: The TVG is inadequate as an independent predictor of the degree of aortic stenosis and outcome from aortic valve replacement in aortic stenosis. In contrast, the TVG may be a useful screening tool for detecting aortic stenosis in targeted elderly populations.     

Evidence of increased matrix metalloproteinase-9 concentration in patients following cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response, which can result in acute lung injury known as "postperfusion syndrome." Neutrophil activation with concomitant serine protease release has been implicated in the pathogenesis of "postperfusion syndrome." Increased plasma levels of neutrophil elastase (NE) have been demonstrated in patients undergoing CPB, and it is well documented that both NE and matrix metalloproteinase-9 (MMP-9) have a synergistic role in pulmonary injury. We, therefore, hypothesized that plasma levels of MMP-9 would be elevated in patients after CPB. Human plasma was obtained after informed consent from eight patients undergoing CPB. Plasma was collected at the start of CPB, 5 minutes after the initiation of CPB, and at the termination of CPB (156 +/- 17 min). All samples were analyzed by both standard enzyme-linked immunosorbent assay (ELISA) and gelatin zymography for MMP-9 (free and total enzyme) concentration. Data were expressed as means +/-SE and assessed by analysis of variance (ANOVA). Plasma MMP-9 concentration was significantly increased at the end of CPB (191 +/- 30.4 ng/mL; p <.05) as compared to both the start of CPB (28.3 +/- 13.2 ng/mL) and 5 minutes after the initiation of CPB (44.3 +/- 15.4 ng/mL). Patients undergoing CPB show an increase in serum MMP-9 levels. Prior studies utilizing an animal model of "postperfusion syndrome" have shown that inhibition of MMP-9 and NE prevented pulmonary injury following CPB. The results of the current study suggest that such an approach may also have merit in the clinical setting of cardiopulmonary bypass.     

腹主动脉瘤发病机理的实验研究 Ⅱ.基质金属蛋白酶-9在大鼠腹主动脉瘤模型中的动态表达

目的 :检测MMP 9在大鼠正常动脉及动脉瘤模型组织中的动态表达 ,以探讨其在腹主动脉瘤发病机制中的作用。方法 :Wistar大鼠 5 4只 ,随机均分为 1组正常对照组、4组灌注对照组和 4组实验组。实验组腹主动脉灌注弹力蛋白酶 (2 5U ml) 2ml,灌注对照组灌注生理盐水 2ml,分别于术前、术后即刻、2d、7d、14d测量腹主动脉直径 ,并采用免疫组织化学和分子原位杂交技术动态检测腹主动脉组织中MMP 9的表达。结果 :正常及灌注对照组腹主动脉组织中均未发现MMP 9,而实验组弹力蛋白酶灌注后2～ 14dMMP 9均有不同程度升高 ,第 7d达到高峰 ,第 14d有所回落。结论 :MMP 9分泌的增加可能与炎症反应有关 ,且为腹主动脉瘤形成中不可或缺的一步。     

胆管癌组织中MMP-9的表达及其意义

目的　探讨基质金属蛋白酶 9(matrixmetalloproteinase 9,MMP 9)在胆管癌发展中的作用及与胆管癌浸润、转移和预后的关系。方法　应用免疫组织化学法 (S P法 )对 5 2例经手术和病理证实的胆管癌及 10例经手术切除的正常胆管壁标本进行MMP 9蛋白检测。结果　 (1)MMP 9表达在胆管癌组织、癌旁组织及正常胆管上皮组织阳性率分别为 84 6 % (4 4 /5 2 )、2 2 6 % (7/31)和 0 %(0 /10 ) ,有显著性差异 (P <0 0 1)。 (2 )在 5 2例胆管癌组织中 ,MMP 9表达分别与肿瘤的病理分级、TNM分期、浸润和转移及手术方式有关 (P <0 0 5 ) ,而与性别、年龄、肿瘤部位及大小无关 (P >0 0 5 )。 (3)MMP 9表达阳性患者一年生存率明显低于阴性者 (P <0 0 1)。结论　MMP 9表达与胆管癌发展、浸润和转移密切相关 ,检测MMP 9的表达有助于对胆管癌转移潜能和预后的判断。     

Systemic dilation diathesis in patients with abdominal aortic aneurysms: a role for matrix metalloproteinase-9?

INTRODUCTION: Accumulating evidence suggests that patients with abdominal aortic aneurysm (AAA) suffer from a systemic dilating condition affecting all arteries. Matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), appear to be involved in aneurysm formation, as evidenced by increased aortic tissue MMP activity and plasma MMP levels in patients with AAA. Hypothesizing that an imbalance in plasma MMP/TIMP level might be associated with a systemic dilation diathesis, we studied mechanical vessel wall properties of non-affected arteries of patients with either AAA or aorto-iliac obstructive lesions in association with plasma MMP-9 and TIMP-1 levels. METHODS: Twenty-two patients with AAA and 12 with aorto-iliac occlusive disease (AOD) were included. Diastolic diameter (d) and distension (Deltad) were measured at the level of the common carotid artery (CCA) and suprarenal aorta (SA) using ultrasonography. Distensibility (DC) and compliance (CC) were calculated from d, Deltad and brachial pulse pressure. Plasma MMP-9 and TIMP-1 were determined with specific immunoassays. RESULTS: The average (+/-SD) age was 72.3+/-5.6 and 65.0+/-8.2 years for the AAA and AOD patients, respectively, (P=0.005). CCA diameter was 9.1+/-1.3mm in AAA patients and AOD 7.8+/-1.4mm in AOD patients, P=0.009. This difference persisted after correction for age. Plasma MMP-9 and TIMP-1 did not differ significantly between AAA and AOD patients. In the total 34 patients, the MMP-9/TIMP-1 ratio was correlated inversely with distensibility (r=-0.74, P=0.002) and to compliance (r=-0.58, P=0.024) of the suprarenal aorta. CONCLUSIONS: The CCA diameter was larger in AAA patients compared to AOD patients. MMP-9/TIMP-1 ratio was associated with decreased distensibility and compliance of the suprarenal aorta. These data support the idea that AAA patients exhibit a systemic dilation diathesis, which might be attributable to MMP/TIMP imbalances.     

基质金属蛋白酶-9与脊髓损伤后脊髓水肿的关系

目的：探讨基质金属蛋白酶-9与急性脊髓损伤后脊髓水肿的关系。方法：健康雄性SD大鼠70只，随机分为对照组和损伤组。对照组大鼠10只，仅做椎板切除术，术后6h取材；损伤组采用改良Allen法制作T8～T9节段脊髓损伤模型，分别于伤后6h、12h、1d、3d、5d、7d（每时间点10只）处死取材。采用干湿重法测定脊髓含水量，免疫组化检测基质金属蛋白酶-9的表达。结果：急性脊髓损伤后6h，损伤组脊髓含水量较对照组增多，3～5d时达到高峰。基质金属蛋白酶-9在对照组未见表达，而损伤组在损伤后6h表达增加，并在1～3d达到高峰，损伤后7d仍有表达。相关性分析显示基质金属蛋白酶-9的表达与脊髓含水量呈正相关。结论：急性脊髓损伤后，基质金属蛋白酶-9的表达与脊髓水肿的形成有关，但两者达到高峰的时间不完全一致。     

绝经后妇女血清基质金属蛋白酶-2、-9与骨转换生化指标及骨密度的关系

目的 探讨绝经后妇女血清成骨细胞分泌的基质金属蛋白酶-2(MMP-2)和破骨细胞分泌的基质金属蛋白酶-9(MMP-9)与骨转换生化指标及骨密度(BMD)之间的关系.方法 选择绝经后妇女80例.采用Challenge双能X线骨密度仪(DXA)测量腰椎(L2-L4)侧位和左侧髋部(股骨颈、大转子、Ward三角区)6个骨骼区域的骨密度(BMD).分为正常对照组(骨密度正常组,21例)、低骨量组(20例)、骨质疏松组(23例)和严重骨质疏松组(骨质疏松骨折组,16例),用酶联免疫吸附试验(ELISA法)测定各组血清MMP-2、MMP-9、血清骨碱性磷酸酶(BAP)、血清骨钙素(OC)和血清Ⅰ型胶原氨基末端肽(NTx).结果 ①绝经后女性各组MMP-2、MMP-9与血清BAP、OC、NTx的变化水平相一致.②绝经后女性血清MMP-2及MMP-9水平随骨密度的降低呈现升高趋势,以骨质疏松骨折组为著.结论 血清MMP-2、MMP-9与骨转换生化指标相关联.血清MMP-2及MMP-9水平升高可能为绝经后骨质疏松症发生的重要影响因素.     

基质金属蛋白酶-9及其抑制物-1在青年特发性气胸肺组织中的表达及意义

目的 探讨基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)及其抑制物-1(tissue inhibitors of metalloproteinase-1,TIMP-1)在青年特发性气胸肺组织中的表达及临床意义.方法 随机选取我科2009年1月至2010年5月治疗的30例青年特发性气胸患者肺大疱组织标本作为实验组,同期获取10例青年正常肺组织标本(因肺裂伤行局部楔形切除肺组织)作为对照组,采用EVG染色法和免疫组织化学SABC法分别观察肺弹力、胶原纤维结构变化及MMP-9与TIMP-1在两组肺组织中的表达状况.结果 实验组中肺弹力、胶原纤维密度稀疏,正常结构伴有明显断裂、萎缩,局部肺泡壁中有纤维缺失;对照组肺组织纤维结构基本完整.MMP-9在实验组肺组织中阳性表达率为76.7%(23/30),在对照组中阳性表达率为30%(3/10);TIMP-1在实验组中阳性表达率为66.7%(20/30),在对照组中阳性表达率为10%(1/10)(P＜0.05).与对照组相比MMP-9 及TIMP-1在实验组中表达明显增多、增强,以TIMP-1表达升高更为显著,且存在MMP-9/TIMP-1表达比例失衡.结论 MMP-9、TIMP-1在局部肺组织中的表达增多、增强及其比值的失衡与肺大疱的形成以及青年特发性气胸的发生、发展有着密切的关系.