Matrix metalloproteinases synthesized in autosomal dominant polycystic kidney disease play a role in development of a concurrent abdominal aortic aneurysm

Abdominal aortic aneurysm is well known to be associated with autosomal dominant polycystic kidney disease. Kidney tubules of autosomal dominant polycystic kidney disease synthesize and secrete high levels of matrix metalloproteinase 2, 3, and 9, especially matrix metalloproteinase 2, and serum matrix metalloproteinase 1 and plasma matrix metalloproteinase 9 concentrations in the disease are significantly higher than those in healthy controls. On the other hand, matrix metalloproteinases play a crucial role in the pathogenesis of abdominal aortic aneurysm. Inflammatory cell expression of matrix metalloproteinase 9 plays a critical role in an experimental model of aortic aneurysm disease. Macrophage-derived matrix metalloproteinase 9 and mesenchymal cell matrix metalloproteinase 2 are both required and work in concert to produce abdominal aortic aneurysm. The plasma matrix metalloproteinase 9 levels are significantly higher in the patients with abdominal aortic aneurysm than in the patients with aortoiliac occlusive disease or the healthy patients. Remarkably elevated matrix metalloproteinase 2 mRNA and protein levels in abdominal aortic aneurysm tissues as compared with normal and atherosclerotic aortic tissues are detected, and matrix metalloproteinase 2 proteolytic activity is several-fold higher in abdominal aortic aneurysms than in other pathological or normal states. Patients with abdominal aortic aneurysm elevate matrix metalloproteinase 2 levels in the vasculature remote from the aorta, supporting both the systemic nature of aneurysmal disease and a primary role of matrix metalloproteinase 2 in aneurysm formation. The authors propose a novel hypothesis that matrix metalloproteinases, synthesized and secreted by kidney tubules of autosomal dominant polycystic kidney disease, play a critical role in development of a concurrent abdominal aortic aneurysm.     

巨噬细胞在腹主动脉瘤中作用的研究进展

主动脉瘤（AAA）是因动脉中层结构破坏,动脉壁不能承受血流冲击的压力所致永久性局部或广泛血管扩张。相关研究证实,在主动脉瘤中被鉴定出来的先天性和获得性免疫细胞,包括嗜中性粒细胞、巨噬细胞、肥大细胞等可促进主动脉瘤的发展。形成AAA的主要危险因素有吸烟和家族史,然而在组织学层面上,AAA的发病特征包括炎症、平滑肌细胞凋亡,细胞外基质降解,氧化应激等。炎症反应在AAA中起着至关重要的作用,且主要影响主动脉壁重塑的决定性因素。本综述关注于主动脉瘤中的巨噬细胞的起源及巨噬细胞在AAA发展过程中的作用,充分描述巨噬细胞的潜在应用。     

Elevated levels of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 during the acute phase of Kawasaki disease

Kawasaki disease (KD) is an acute, self-limiting, multisystem vasculitis of unknown etiology affecting infants and young children. Unless treated promptly with high-dose intravenous gamma globulin and aspirin, patients frequently develop coronary aneurysms. Previously, matrix metalloproteinase 9 (MMP-9), which is secreted complexed to tissue inhibitor of metalloproteinase 1 (TIMP-1), has been implicated in abdominal aortic aneurysm formation. Since the clinical and pathological features of KD include inflammation and weakening of blood vessels, we analyzed acute- and convalescent-phase paired plasma or serum samples from 31 KD patients, 7 patients who did not completely meet the criteria for KD, and 26 non-KD controls (9 febrile and 17 afebrile patients) for pro-MMP-9 (92 kDa) enzyme activity by gelatin zymography and for active MMP-9 (83 kDa), pro-MMP-9, and TIMP-1 protein levels by enzyme-linked immunosorbent assay. Statistical analysis was performed by using Student t tests, linear regression, and the Wilcoxon rank-sum test. Markedly elevated pro-MMP-9 enzymatic activity, pro-MMP-9 protein levels, and TIMP-1 protein levels were found during the acute phase of illness in patients with clinically established KD and in patients who were suspected of having KD but did not meet all of the criteria. There was no significant difference in active MMP-9 levels. Furthermore, pro-MMP-9 and TIMP-1 protein levels were significantly elevated among KD patients, compared to those of febrile and afebrile non-KD controls. The significantly elevated pro-MMP-9 enzyme and protein levels during the acute phase of KD may reflect vascular remodeling or an inflammatory response to a microbial agent, suggesting a pathophysiological role for MMP-9 in coronary aneurysm formation.     

基质金属蛋白酶及其抑制剂在腹主动脉瘤发病中的作用

随着现代医学的发展 ,腹主动脉瘤 (ａｂｄｏｍｉｎａｌａｏｒｔｉｃａｎｅｕｒｙｓｍｓ ,ＡＡＡ)在临床上已得到有效治疗 ,但本病的促发因素以及持续扩张以致破裂的控制因素仍存在较大的争议 ,经过免疫、遗传、分子生物学及血流动力学等方面的广泛研究 ,所有学者均认为腹主动脉壁的基质降解是ＡＡＡ形成和发展的关键环节 ,基质金属蛋白酶 (ｍａｔｒｉｘｍｅｔａｌｌｏｐｒｏｔｅｉｎａｓｅ ,ＭＭＰ)是破坏细胞外基质 (ｅｘｔｒａｃｅｌｌｕｌａｒｍａｔｒｉｘ ,ＥＣＭ )中最主要一类酶系 ,本文就ＭＭＰ及其抑制剂类别功能、来源与表达以及两…     

Antifibrotic effects of crocetin in scleroderma fibroblasts and in bleomycin-induced sclerotic mice

OBJECTIVE:

To investigate the antifibrotic effects of crocetin in scleroderma fibroblasts and in sclerotic mice.

METHODS:

Skin fibroblasts that were isolated from three systemic scleroderma (SSc) patients and three healthy subjects were treated with crocetin (0.1, 1 or 10 μM). Cell proliferation was measured with an MTT assay. Alpha-smooth muscle actin was detected via an immunohistochemical method. Alpha 1 (I) procollagen (COL1A1), alpha 1 (III) procollagen (COL3A1), matrix metalloproteinase (MMP)-1 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 mRNA levels were measured using real-time PCR. SSc mice were established by the subcutaneous injection of bleomycin. Crocetin (50 mg/kg/d) was injected intraperitoneally for 14 days. Dermal thickness and lung fibrosis were assessed with Masson''s trichrome staining. Plasma ET-1 was detected with an enzyme-linked immunosorbent assay (ELISA). Skin and lung ET-1 and COL1A1 mRNA levels were measured via real-time PCR.

RESULTS:

Crocetin inhibited the proliferation of SSc and normal fibroblasts, an effect that increased with crocetin concentration and incubation time. Crocetin decreased the expression of α-SMA and the levels of mRNA for COL1A1, COL3A1 and matrix metalloproteinase-1, while crocetin increased TIMP-1 mRNA levels in both SSc and normal fibroblasts. Skin and lung fibrosis was induced, and the levels of ET-1 in the plasma, skin and lungs were elevated in bleomycin-injected mice. Crocetin alleviated the thickening of the dermis and lung fibrosis; decreased COL1A1 mRNA levels in the skin and lung; and simultaneously decreased ET-1 concentrations in the plasma and ET-1 mRNA levels in the skin and lungs of the bleomycin-induced sclerotic mice, especially during the early phase (weeks 1-3).

CONCLUSION:

Crocetin inhibits cell proliferation, differentiation and collagen production in SSc fibroblasts. Crocetin alleviates skin and lung fibrosis in a bleomycin-induced SSc mouse model, in part due to a reduction in ET-1.     

川崎病患儿血清MMP-9、TIMP-1、ET-1水平的变化及其临床意义

目的探讨川崎病（KD）患儿不同时期血清基质金属蛋白酶（MMP-9）、组织基质金属蛋白酶抑制物（TIMP-1）、内皮素-1（ET-1）水平的变化及其与冠状动脉病变之间的关系。方法采用酶联免疫吸附法（ELISA）、放免法（RIA）对34例KD患儿急性期、治疗后5d、亚急性期和恢复期血清MMP-9、TIMP-1、ET-1水平进行检测,并与34例正常健康儿童进行对照。同时应用心脏彩超检测KD患儿冠状动脉的病变。结果KD患儿不同时期血清MMP．9、TIMP．1、ET-1水平及MMP-9／TIMP-1比值组间有差异。KD患儿血清MMP-9、TIMP-1、MMP-9／TIMP-1及ET-1（292．56±28．65）μg／L、（394．50±46．80）μg／L、（0．75±0．11）、（80．65±14．00）pg／ml均明显高于正常对照组（27．53±11．67）／μg／L、（100．47±32.96）μg/L、（0．28±0．10）、（52．70±11．39）pg／ml,其中冠脉扩张组血清MMP-9／TIMP-1显著高于无扩张组,且与冠脉扩张程度呈正相关（r=0．83）,而扩张组血清MMP-9、ET-1水平与无扩张组之间无显著差异,血清TIMP-1水平低于无扩张组。结论血清MMP-9、TIMP-1、ET-1可能参与了川崎病的病理发病机制,血清MMP-9／TIMP-1持续失衡,可作为预测川崎病并发冠状动脉炎,尤其是冠状动脉扩张的生化指标之一。     

Regulation of matrix metalloproteinases and their inhibitors in the left ventricular myocardium of patients with aortic stenosis

Aortic stenosis (AS) results in myocyte and extracellular matrix remodeling in the human left ventricle (LV). The myocardial renin-angiotensin system is activated and collagens I and III and fibronectin accumulate. We determined the yet unknown regulation of enzymes that control collagen turnover, i.e., LV matrix metalloproteinases (MMP) and their tissue inhibitors (TIMPs) in human AS. We compared LV samples from AS patients undergoing elective aortic valve replacement (n=19) with nonused donor hearts with normal LV function (controls, n=12). MMP-2, MMP-9, MT1-MMP, and extracellular matrix metalloproteinase inducer (EMMPRIN), TIMP-1, TIMP-2, TIMP-3, and TIMP-4 mRNA were quantitated by real-time RCR. MMP-1, MMP-2, MMP-3, TIMP-3, TIMP-4, and EMMPRIN protein were measured by immunoblotting and MMP-9 and TIMP-1 protein by ELISA. Gelatinolytic MMP-2 and MMP-9 activity was measured by zymography. MMP-2 was increased in AS at mRNA, protein, and activity levels (131%, 193%, and 138% of controls). MMP-3 protein (308%) and EMMPRIN mRNA and protein were also upregulated (171% and 200%). In contrast, MMP-1 (37%) and MMP-9 mRNA, protein, and activity (26%, 21%, and 52%) were downregulated. MMP-9 activity was inversely correlated with LV size. TIMP-1 mRNA and protein were decreased (55% and 73%). In contrast, TIMP-2 mRNA (358%), TIMP-3 mRNA and protein (145% and 249%) were increased. TIMP-4 mRNA was not altered, but TIMP-4 protein was upregulated to 350%. Changes were similar in AS patients with normal and impaired LV ejection fraction. The dysregulation of myocardial MMPs and TIMPs in human AS starts at an early disease stage when LV function is still normal. In spite of upregulation of some MMPs the balance between MMP and TIMP is shifted towards MMP inhibition in human AS and may contribute to collagen accumulation.     

Elevated Levels of Matrix Metalloproteinase 9 and Tissue Inhibitor of Metalloproteinase 1 during the Acute Phase of Kawasaki Disease

Kawasaki disease (KD) is an acute, self-limiting, multisystem vasculitis of unknown etiology affecting infants and young children. Unless treated promptly with high-dose intravenous gamma globulin and aspirin, patients frequently develop coronary aneurysms. Previously, matrix metalloproteinase 9 (MMP-9), which is secreted complexed to tissue inhibitor of metalloproteinase 1 (TIMP-1), has been implicated in abdominal aortic aneurysm formation. Since the clinical and pathological features of KD include inflammation and weakening of blood vessels, we analyzed acute- and convalescent-phase paired plasma or serum samples from 31 KD patients, 7 patients who did not completely meet the criteria for KD, and 26 non-KD controls (9 febrile and 17 afebrile patients) for pro-MMP-9 (92 kDa) enzyme activity by gelatin zymography and for active MMP-9 (83 kDa), pro-MMP-9, and TIMP-1 protein levels by enzyme-linked immunosorbent assay. Statistical analysis was performed by using Student t tests, linear regression, and the Wilcoxon rank-sum test. Markedly elevated pro-MMP-9 enzymatic activity, pro-MMP-9 protein levels, and TIMP-1 protein levels were found during the acute phase of illness in patients with clinically established KD and in patients who were suspected of having KD but did not meet all of the criteria. There was no significant difference in active MMP-9 levels. Furthermore, pro-MMP-9 and TIMP-1 protein levels were significantly elevated among KD patients, compared to those of febrile and afebrile non-KD controls. The significantly elevated pro-MMP-9 enzyme and protein levels during the acute phase of KD may reflect vascular remodeling or an inflammatory response to a microbial agent, suggesting a pathophysiological role for MMP-9 in coronary aneurysm formation.     

Expression of metalloproteinases and its inhibitor in later stage of rabbit neointima development

Neointima formation after arterial de-endothelialization refers not only to smooth muscle cell (SMC) migration and proliferation, but also involves extracellular matrix (ECM) metabolism. Most studies regarding the role of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in neointima have focused on the early phase of vascular remodeling. In this study, we examined the expression of MMP and TIMP in rabbit aortic neointima at a relatively late stage of lesion development, between 4 and 12 weeks after initial de-endothelialization. Northern blot analysis revealed expression of steady-state MMP-9 mRNA was increased up to the 4th week and MMP-2 mRNA to the 12th week after de-endothelialization. In situ hybridization shown that MMP positive cells were predominantly distributed in arterial neointima. Expression of TIMP-1 mRNA was continuously up-regulated up to the 12th week and TIMP-1 positive cells, primarily SMCs, were also localized to the neointimal tissue. Alteration at mRNA level was accompanied by that at protein level, as assessed by SDS-PAGE zymography for MMPs and immunoblotting for TIMP-1. The profile of alteration at protein level correlated well with that at mRNA level. These data suggest that synthesis of MMPs and TIMP is a prolonged process and arterial SMC is a major source of MMP production in arterial neointima. Enhanced synthesis of MMPs and TIMPs at late stage of neointimal development may contribute to arterial ECM metabolism.     

Enhanced production of the chemotactic cytokines interleukin-8 and monocyte chemoattractant protein-1 in human abdominal aortic aneurysms.

Inflammatory leukocytes play a central role in the pathogenesis of human atherosclerotic disease, from early atherogenesis to the late stages of atherosclerosis, such as aneurysm formation. We have shown previously that human abdominal aortic aneurysms are characterized by the presence of numerous chronic inflammatory cells throughout the vessel wall (Am J Pathol 1990, 137: 1199-1213). The signals that attract lymphocytes and monocytes into the aortic wall in aneurysmal disease remain to be precisely defined. We have studied the production of the chemotactic cytokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) by aortic tissues obtained from 47 subjects. We compared the antigenic production of these cytokines by explants of: 1) human abdominal aneurysmal tissue, 2) occlusive (atherosclerotic) aortas, and 3) normal aortas. IL-8, which is chemotactic for neutrophils, lymphocytes, and endothelial cells was liberated in greater quantities by abdominal aortic aneurysms than by occlusive or normal aortas. Using immunohistochemistry, macrophages, and to a lesser degree endothelial cells, were found to be positive for the expression of antigenic IL-8. Similarly, MCP-1, a potent chemotactic cytokine for monocytes/macrophages, was released by explants from abdominal aortic aneurysms in greater quantities than by explants from occlusive or normal aortas. Using immunohistochemistry, the predominant MCP-1 antigen-positive cells were macrophages and to a lesser extent smooth muscle cells. Our results indicate that human abdominal aortic aneurysms produce IL-8 and MCP-1, both of which may serve to recruit additional inflammatory cells into the abdominal aortic wall, hence perpetuating the inflammatory reaction that may result in the pathology of vessel wall destruction and aortic aneurysm formation.     

Atherosklerose/Aortenaneurysmen

Patients with obstructive sleep apnea (OSA) show a high prevalence of atherosclerotic disorders. Furthermore, they have evidence for accelerated vascular remodeling which is probably due to intermittent nocturnal hypoxia. Similarly, the prevalence of OSA is increased in patients suffering from aortic dissections and aneurysms. In addition, the presence of OSA is linked with more rapid aneurysm growth. The OSA-associated arterial hypertension with its characteristic non-dipping during sleep is supposed to play a key role within this context. Continuous positive airway pressure therapy may attenuate atherosclerosis, whereas its effects on the development and progression of aortic aneurysms have not yet been investigated.     

Elastin-laminin receptor and abdominal aortic aneurysms. New subject to study? A review.

Abdominal aortic aneurysms and their management remain a significant health problem that is likely to assume greater importance with the expansion of the elderly population. Elastin fibres degradation and extracellular matrix remodelling seems to be the basic process in aneurysm formation. Recent investigations revealed the principal role of elastin-laminin receptor in extracellular matrix remodelling in aging and atherosclerosis. The correlation between events observed in animal aneurysm models, human aneurysms and in experiments on elastin-laminin receptor properties was discussed to propose the hypothesis about the role of elastin peptides and elastin-laminin receptor in aortic aneurysm formation.     

Changes of gene expression after bone marrow cell transfusion in rats with monocrotaline-induced pulmonary hypertension

Pulmonary artery hypertension (PAH) causes right ventricular failure and possibly even death by a progressive increase in pulmonary vascular resistance. Bone marrow-derived mesenchymal stem cell therapy has provided an alternative treatment for ailments of various organs by promoting cell regeneration at the site of pathology. The purpose of this study was to investigate changes of pulmonary haemodynamics, pathology and expressions of various genes, including ET (endothelin)-1, ET receptor A (ERA), endothelial nitric oxide synthase (NOS) 3, matrix metalloproteinase (MMP) 2, tissue inhibitor of matrix metalloproteinase (TIMP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α in monocrotaline (MCT)-induced PAH rat models after bone marrow cell (BMC) transfusion. The rats were grouped as the control (C) group, monocrotaline (M) group, and BMC transfusion (B) group. M and B groups received subcutaneous (sc) injection of MCT (60 mg/kg). BMCs were transfused by intravenous injection at the tail 1 week after MCT injection in B group. Results showed that the average RV pressure significantly decreased in the B group compared with the M group. RV weight and the ratio of RH/LH+septum significantly decreased in the B group compared to the M group. Gene expressions of ET-1, ERA, NOS 3, MMP 2, TIMP, IL-6, and TNF-α significantly decreased in week 4 in the B group compared with the M group. In conclusion, BMC transfusion appears to improve survival rate, RVH, and mean RV pressure, and decreases gene expressions of ET-1, ERA, NOS 3, MMP 2, TIMP, IL-6, and TNF-α.     

Expression of matrix metalloproteinases, their tissue inhibitors, and osteopontin in the wall of thoracic and abdominal aortas with dilatative pathology

Matrix metalloproteinases (MMPs) degrade extracellular matrix and may play a central role in the pathogenesis of aortic aneurysms. We studied 2 groups of patients: 15 with dilatative pathology of the ascending thoracic aorta and 17 with aneurysm of the abdominal aortic wall (AAA). We compared the expression of MMPs, tissue inhibitors of matrix metalloproteinases (TIMPs), and osteopontin in the wall of thoracic and abdominal aneurysms. In AAA, MMP-9 and TIMP-1 expression in inflammatory cells was higher than in smooth muscle cells (SMCs) (median score: 3.5 versus 1, P < .0001; 2 versus 1, P < .04, respectively), whereas MMP-2 demonstrated higher expression in SMCs than in inflammatory cells (median score: 0 versus 4, P < .0001). In ATA, MMP-2, MMP-9, TIMP-1, TIMP-2, TIMP-3, and osteopontin expression in SMCs was higher than in inflammatory cells (median score: 3 versus 0, P < .0001; 4 versus 1, P < .0005; 2 versus 0, P < .001; 5 versus 2, P < .0001; 2 versus 0, P < .005; and 5 versus 1.5, P < .0001, respectively), when both inflammatory cells of the media and the adventitia were considered together. The cellular expression of MMP-9 and their tissue inhibitors TIMP-1, TIMP-2, and TIMP-3 differs in the dilatative pathology of abdominal and thoracic aortas, so the hypothetical model of morphogenesis of AAA cannot completely explain the formation of dilatative pathology of the ascending thoracic aorta.     

The inhibitory effect of preeclamptic umbilical cord blood serum on matrix metalloproteinase-1 in arterial slices incubated in vitro.

BACKGROUND: Our previous studies demonstrated that preeclampsia is accompanied by significant alterations in the amounts of peptide growth factors in the umbilical cord serum. Some of these factors (especially IGF-1) are known as regulators of collagen metabolism. The umbilical cord arteries (UCAs) of newborns delivered by mothers with preeclampsia contain more than twice the amount of collagen in comparison to newborns delivered by healthy mothers. A significant role in collagen degradation is attributed to matrix metalloproteinase (MMP)-1 (collagenase 1) and tissue inhibitors of metalloproteinases (TIMPs). OBJECTIVE: To compare the effects of umbilical cord (UC) blood serum of control and preeclamptic newborns on the content and activity of MMP-1, TIMP-1 and TIMP-2 in UCA wall slices incubated in vitro. METHODS: Polyacrylamide gel electrophoresis (PAGE) followed by Western immunoblotting allowed to detect MMP-1 as well as TIMP-1 and TIMP-2. The amounts of MMP-1, TIMP-1 and TIMP-2 in UCA slices were measured by immunoenzymatic method (ELISA). MMP-1 activity in the arterial wall was measured using a collagenase-1-specific substrate. RESULTS: Western immunoblot analyses detected MMP-1, TIMP-1 and TIMP-2 in the incubation fluids and in extracts from the UCA wall. Both 43- and 55-kDa (a zymogen) bands of MMP-1 were visible. The control UC serum stimulated both the amount as well as actual and potential activities of MMP-1 in the arterial wall in a time-dependent manner. In contrast to controls, the preeclamptic serum did not exert such an effect. CONCLUSIONS: The small amount and low activity of MMP-1 accompanied by elevated amounts of TIMPs (especially TIMP-1) decelerate the degradation and enhance the accumulation of collagen in the preeclamptic UCA wall.     

Gingival Fibroblasts Inhibit MMP-1 and MMP-3 Activities in an Ex-Vivo Artery Model

The main arterial pathologies can be associated with a deregulation of remodeling involving matrix metalloproteinases (MMPs), whereas gingival healing is characterized by an absence of fibrosis or irreversible elastin/collagen degradation. The aim of our study was to evaluate the effect of gingival fibroblasts on MMP-1 and MMP-3 secretion in an organotypic artery culture. MMP-1 and MMP-3 secretions and activities (dot blots, zymography, ELISA) were evaluated in coculture of rabbit artery in the presence or not of gingival fibroblasts. MMP-1/TIMP-1 and MMP-3/TIMP-1 complexes forms were measured by ELISA. Complementary studies were performed using human aortic smooth muscle cells cocultured with adventitial, dermal, or gingival fibroblasts. Our results indicated that MMP-1 and MMP-3 free-forms activities were significantly reduced in coculture. This inhibition was linked to a significant increase of TIMP-1 leading to formation of TIMP-1/MMPs complexes. Due to the presence of gingival fibroblasts, the decrease in MMP-1 and MMP-3 efficiency thus contributes to diminish the degradation of artery. This cellular therapy strategy could be promising in artery pathologies treatment.     

Evidence in favor of the contribution of genes involved in the maintenance of the extracellular matrix of the arterial wall to the development of intracranial aneurysms.

Intracranial aneurysm is probably a complex disease with both genetic and non-genetic or environmental risk factors contributing to the etiology of the disease. A disruption of the extracellular matrix (ECM) of the arterial wall is a likely factor in the pathogenesis of intracranial aneurysms. We analyzed 44 potential candidate genes involved in the maintenance of the integrity of the ECM in 382 Dutch Caucasian patients with intracranial aneurysms and 609 Dutch Caucasian controls for 384 tag single nucleotide polymorphisms (SNPs) using the GoldenGate assay on an Illumina BeadStation 500 GX. We identified SNPs that were associated with intracranial aneurysms (P<0.01) in six of these 44 genes: serpine1 (SERPINE1, P=0.0008), transforming growth factor beta induced (TGFBI, P=0.0026), perlecan (HSPG2, P=0.0044), fibronectin (FN1, P=0.0069), fibrillin 2 (FBN2, P=0.0077) and alpha 1 type IV collagen (COL4A1, P=0.0087). In a second independent cohort of 310 Dutch Caucasian intracranial aneurysm patients and 336 Dutch Caucasian controls, the association for the HSPG2 gene [combined odds ratio (OR) 1.33, 95% confidence interval (CI) 1.13-1.57, P=6 x 10(-4)] was replicated. The population attributable risk (PAR) for this SNP is 19%. Combining the two cohorts still showed association for the SERPINE1 (combined OR 1.27, 95% CI 1.07-1.50, P=0.004, PAR 6%), FBN2 (combined OR 1.37, 95% CI 1.07-1.75, P=0.01, PAR 3%) and COL4A1 (combined OR 1.22, 95% CI 1.05-1.42, P=0.007, PAR 7%) genes. These PARs are likely to be overestimates as they are calculated from the joint analyses combining stages 1 and 2 of our association study. Our findings indicate that variation in genes involved in the maintenance of the integrity of the ECM of the arterial wall plays a role in susceptibility to intracranial aneurysms. These findings further support our hypothesis that diminished maintenance of the ECM of the arterial wall is important in the development of intracranial aneurysms.     

Gingival fibroblasts inhibit MMP-1 and MMP-3 activities in an ex-vivo artery model

The main arterial pathologies can be associated with a deregulation of remodeling involving matrix metalloproteinases (MMPs), whereas gingival healing is characterized by an absence of fibrosis or irreversible elastin/collagen degradation. The aim of our study was to evaluate the effect of gingival fibroblasts on MMP-1 and MMP-3 secretion in an organotypic artery culture. MMP-1 and MMP-3 secretions and activities (dot blots, zymography, ELISA) were evaluated in coculture of rabbit artery in the presence or not of gingival fibroblasts. MMP-1/TIMP-1 and MMP-3/TIMP-1 complexes forms were measured by ELISA. Complementary studies were performed using human aortic smooth muscle cells cocultured with adventitial, dermal, or gingival fibroblasts. Our results indicated that MMP-1 and MMP-3 free-forms activities were significantly reduced in coculture. This inhibition was linked to a significant increase of TIMP-1 leading to formation of TIMP-1/MMPs complexes. Due to the presence of gingival fibroblasts, the decrease in MMP-1 and MMP-3 efficiency thus contributes to diminish the degradation of artery. This cellular therapy strategy could be promising in artery pathologies treatment.     

Intracerebroventricular administration of an endothelin ETB receptor agonist increases expression of tissue inhibitor of matrix metalloproteinase-1 and -3 in rat brain

Production of tissue inhibitors of matrix metalloproteinases (TIMPs), a family of secreted proteins with inhibitory actions on matrix metalloproteinases (MMPs), is up-regulated following nerve injuries and is suggested to have protective effects against MMP-mediated tissue damages. To clarify the extracellular signals involved in TIMP production in the brain, the effects of endothelins (ETs), a family of vasoconstricting peptides, were examined. I.c.v. administration of 500 pmol/day Ala(1,3,11,15)-ET-1, an ET(B) receptor agonist, increased the level of TIMP-1 mRNA in rat hippocampus, caudate-putamen and cerebrum. Ala(1,3,11,15)-ET-1 increased the level of TIMP-3 mRNA in the cerebrum, but not in the hippocampus or caudate-putamen. TIMP-2 mRNA was not affected in these brain regions. Ala(1,3,11,15)-ET-1 also stimulated the production of TIMP-1 and TIMP-3 proteins in the cerebrum. Immunohistochemical observations in the hippocampi of Ala(1,3,11,15)-ET-1-infused rats showed that NeuN-positive neurons and glial fibrillary acidic protein-positive astrocytes were immunoreactive for TIMP-1. In the cerebrum, astrocytes had TIMP-1 and TIMP3 reactivity, but neurons did not. In rat cultured astrocytes, both 100 nM Ala(1,3,11,15)-ET-1 and ET-1 increased the mRNA levels and protein release of TIMP-1 and TIMP-3 mRNAs. The effects of ET-1 on astrocytic TIMP-1 and TIMP-3 mRNAs were inhibited by BQ788, an ET(B) antagonist. These findings indicate that activation of brain ET(B) receptors causes production of TIMP-1 and TIMP-3, and suggest the involvement of astrocytes in ET-induced TIMP production.     

Prognostic value of tissue factor in patients with abdominal aortic and iliac arterial aneurysms – preliminary study

Introduction

The decision on the time and choice of strategy of treatment of abdominal aortic aneurysm must be especially carefully balanced. The aim of the study was to evaluate the tissue factor (TF) plasma level as a potential factor useful in anticipation of abdominal aortic aneurysm and/or iliac arterial aneurysm via comparison of plasma TF level in patients with ruptured and non-ruptured aneurysms.

Material and methods

The study included 33 patients with aneurysm (17 operated on electively because of non-ruptured aneurysm and 16 operated on emergently due to ruptured aneurysm), 33 claudicant patients with atherosclerosis of the abdominal aorta and iliac arteries with normal diameter of arteries, and 30 healthy controls. Plasma TF level was assessed by ELISA method using the IMUBIND Tissue Factor ELISA Kit (American Diagnostica Inc.).

Results

The study showed an increased TF level in patients with aneurysm (134 ±54 pg/ml) and in patients with atherosclerosis without concomitant aneurysm (91 ±30 pg/ml) in comparison with the control group (62 ±20 pg/ml), respectively p < 0.001 and p = 0.008. A significantly higher TF plasma level was observed in patients with ruptured abdominal aortic aneurysms (160 ±57 pg/ml) as compared to patients with non-ruptured aortic aneurysms (109 ±39 pg/ml) or peripheral arterial occlusive disease (91 ±30 pg/ml), respectively p < 0.001 and p < 0.001. The difference in TF level between the group with non-ruptured aortic aneurysms (109 ±39 pg/ml) and the patients with atherosclerosis without aneurysm (91 ±30 pg/ml) was not statistically significant.

Conclusions

No difference in TF level between patients with non-ruptured AAA/IAA and patients with aortic and iliac atherosclerosis without aneurysm indicates that an increased TF plasma level is not specific for any of the above-mentioned vascular pathologies.