Inhibitory mechanisms of activated matrix metalloproteinase-9 on platelet activation

The intracellular mechanisms underlying the signaling pathways of activated matrix metalloproteinase-9 (MMP-9) in platelets are not yet completely understood. Therefore, the aim of this study was to further examine the effects of activated MMP-9 in preventing platelet aggregation. In this study, activated MMP-9 time-dependently (3-60 min) inhibited platelet aggregation in washed human platelet suspensions stimulated by agonists. However, activated MMP-9 had no significant effect on the binding of FITC-triflavin to the platelet glycoprotein IIb/IIIa complex. Triflavin is a specific antagonist of the glycoprotein IIb/IIIa complex purified from snake venom. Moreover, activated MMP-9 (21 and 90 ng/ml) markedly decreased the fluorescence intensity of platelet membranes tagged with diphenylhexatriene. The thrombin-evoked increase in pHi was inhibited in the presence of activated MMP-9 (21 and 90 ng/ml). In addition, activated MMP-9 (21 and 90 ng/ml) markedly reduced the electron spin resonance (ESR) signal intensity of hydroxyl radicals in collagen (1 mug/ml)-activated platelets. These results indicate that the antiplatelet activity of activated MMP-9 may involve the following pathways: (1) activated MMP-9 may initially induce conformational changes in platelet membranes and hydroxyl radical formation, leading to inhibition of platelet aggregation; and (2) activated MMP-9 also inhibits the Na(+)/H(+) exchanger, leading to reduced intracellular Ca(2+) mobilization, and ultimately to inhibition of platelet aggregation. This study further provides new insights concerning the effects of activated MMP-9 on platelet aggregation.     

Expression of matrix metalloproteinase-9 in thyroid tumors tissue

目的 探讨基质金属蛋白酶-9(MMP-9)在甲状腺肿瘤组织的表达情况.方法 采用免疫组织化学SP法检测20例瘤旁甲状腺组织、20例甲状腺腺瘤和53例甲状腺癌的石蜡标本MMP-9表达水平.结果 MMP-9在甲状腺腺癌的表达率显著高于甲状腺腺瘤(96.41% vs 55%,P＜0.01),瘤旁甲状腺组织未见表达.结论 甲状腺肿瘤存在MMP-9的过表达.     

基质金属蛋白酶-9在甲状腺肿瘤组织中的表达

目的探讨基质金属蛋白酶-9(MMP-9)在甲状腺肿瘤组织的表达情况。方法采用免疫组织化学SP法检测20例瘤旁甲状腺组织、20例甲状腺腺瘤和53例甲状腺癌的石蜡标本MMP-9表达水平。结果 MMP-9在甲状腺腺癌的表达率显著高于甲状腺腺瘤(96.41%vs 55%,P<0.01),瘤旁甲状腺组织未见表达。结论甲状腺肿瘤存在MMP-9的过表达。     

Effects of verapamil and nisoldipine on human platelets: in vivo and in vitro studies.

Inhibition of platelet aggregation was observed after 4 days of oral dosing with the calcium antagonists, verapamil (160 mg) or nisoldipine (20 mg) but not following acute dosing. These effects were observed at plasma concentrations that had no effect on platelet aggregation when investigated in vitro. Verapamil added in vitro inhibited adrenaline-induced platelet aggregation at relatively low concentrations (IC50 16 microM) but only inhibited aggregation to adenosine diphosphate at very high concentrations (IC50 700 microM). Nisoldipine, a dihydropyridine, added in vitro had no effect on platelet aggregation induced by adenosine diphosphate but inhibited by 67%, the secondary phase of platelet aggregation induced by adrenaline. Verapamil but not nisoldipine displaced [3H]-yohimbine from the specific binding sites on human platelets, suggesting an interaction with alpha 2-adrenoceptors. Inhibition of adrenaline-induced aggregation by verapamil in vitro may be a result of antagonism of alpha 2-adrenoceptors but long term treatment with both verapamil and nisoldipine also inhibits platelet aggregation mechanisms other than by alpha 2-adrenoceptor blockade.     

类风湿关节炎患者基质金属蛋白酶-8的表达

目的　用单克隆抗体检测类风湿关节炎 (RA)和强直性脊柱炎 (AS)患者滑液和血浆中基质金属蛋白酶 8(MMP 8)的表达。方法　采用酶联免疫吸附试验 (ELISA)方法测定正常人、RA和AS滑液和血浆中MMP 8的表达。结果　①正常人、RA和AS血浆中MMP 8的浓度均为 1～ 2 3μg L ;②正常人和AS滑液中MMP 8的浓度为10～ 2 0 μg L ;③RA滑液中MMP 8的浓度为 90～ 2 80 0 μg L。 结论　①RA患者与正常人和AS患者血浆中MMP 8的浓度差异无显著性。②MMP 8在关节滑液的浓度 ,RA患者远高于正常人和AS患者。     

E-钙粘蛋白和MMP-9在胃癌组织中的表达及其临床意义

目的研究E-钙粘蛋白（E-Cadherin,E-Cad）和基质金属蛋白酶9（Matrix metalloprotein-ase-9,MMP-9）在胃癌中的表达,及其与胃癌临床病理特征、淋巴结转移和患者预后之间的关系。方法应用免疫组织化学方法,检测正常胃粘膜和胃癌标本的E-Cad和MMP-9表达。结果在胃癌组织中,E-Cad呈低表达,阳性表达率为53.7%,明显低于正常胃粘膜组织（P〈0.05）,其表达率与肿瘤大小、肿瘤分化、TNM分期显著相关（P〈0.05）,但与淋巴结转移无明显相关性（P〉0.05）;E-Cad表达阳性者,其5年生存期率较高（P〈0.05）。MMP-9在胃癌组织中呈高表达（75.0%）,明显高于正常组织,且与淋巴结转移、肿瘤大小、肿瘤分化、分期以及生存期显著相关（P〈0.05）。结论胃癌广泛存在E-钙粘蛋白及MMP-9表达异常,且与预后密切相关。     

S-nitroso-glutathione inhibits platelet activation in vitro and in vivo.

1. The effect of S-nitroso-glutathione (GSNO), a stable nitrosothiol, on platelet activation was examined in vitro and in vivo. 2. The adhesion of human platelets to fibrillar collagen and human endothelial cell monolayers was inhibited by GSNO. 3. GSNO caused a concentration-dependent inhibition of collagen-induced platelet aggregation in vitro and decreased ADP-induced aggregation in the conscious rat. 4. Inhibition of platelet aggregation in vitro correlated with the increase in intraplatelet cyclic GMP levels. 5. The release of NO from GSNO was enhanced by platelet lysate, native glutathione and ascorbate. 6. The results show that GSNO is a carrier of NO and therefore has pharmacological activity as an inhibitor of platelet activation.     

MMP-9及CD147在下咽癌中的表达及其临床意义

目的探讨基质金属蛋白酶-9(MMP-9)及CD147在下咽癌中的表达及其相互关系.方法用免疫组织化学方法研究MMP-9及CD147在33例下咽癌组织(下咽癌组)和15例正常喉粘膜标本(对照组)中的表达.结果MMP-9及CD147在下咽癌组中的表达高于对照组(分别为P＜0.01和P＜0.05);在有淋巴结转移的下咽癌组中的表达高于无淋巴结转移组(P＜0.05);MMP-9及CD147的表达之间存在明显的相关性.结论MMP-9及CD147均可作为反映下咽癌癌生物学行为的客观参考指标,可有助于下咽癌治疗方案的制定.     

颈动脉粥样硬化斑块患者血清基质金属蛋白酶9的表达及意义

目的 探讨颈动脉粥样硬化斑块与血清基质金属蛋白酶9 (MMP-9)水平的关系.方法 选取30例经彩色多普勒超声证实存在颈动脉粥样硬化斑块的患者为研究组,其中稳定斑块18例,不稳定斑块12例,30例健康查体者为对照组.均抽取空腹血应用酶联免疫吸附法检测血清MMP-9水平.结果 研究组的MMP-9表达为(295.34±126.76) μg/L,明显高于对照组的(98.38±34.57)μg/L(t =4.835,P＜0.05);研究组稳定斑块患者中MMP-9的表达为(267.45±113.86) μg/L,明显低于不稳定斑块患者的(498.57±142.68) μg/L(t =3.768,P＜0.05).结论 血清MMP-9水平与颈动脉粥样硬化斑块形成有关,可以反映颈动脉粥样硬化斑块的稳定性.     

Anacardic Acid inhibits the catalytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9

Cashew nut shell liquid (CNSL) has been used in traditional medicine for the treatment of a wide variety of pathophysiological conditions. To further define the mechanism of CNSL action, we investigated the effect of cashew nut shell extract (CNSE) on two matrix metalloproteinases, MMP-2/gelatinase A and MMP-9/gelatinase B, which are known to have critical roles in several disease states. We observed that the major constituent of CNSE, anacardic acid, markedly inhibited the gelatinase activity of 3T3-L1 cells. Our gelatin zymography studies on these two secreted gelatinases, present in the conditioned media from 3T3-L1 cells, established that anacardic acid directly inhibited the catalytic activities of both MMP-2 and MMP-9. Our docking studies suggested that anacardic acid binds into the MMP-2/9 active site, with the carboxylate group of anacardic acid chelating the catalytic zinc ion and forming a hydrogen bond to a key catalytic glutamate side chain and the C15 aliphatic group being accommodated within the relatively large S1' pocket of these gelatinases. In agreement with the docking results, our fluorescence-based studies on the recombinant MMP-2 catalytic core domain demonstrated that anacardic acid directly inhibits substrate peptide cleavage in a dose-dependent manner, with an IC(50) of 11.11 μM. In addition, our gelatinase zymography and fluorescence data confirmed that the cardol-cardanol mixture, salicylic acid, and aspirin, all of which lack key functional groups present in anacardic acid, are much weaker MMP-2/MMP-9 inhibitors. Our results provide the first evidence for inhibition of gelatinase catalytic activity by anacardic acid, providing a novel template for drug discovery and a molecular mechanism potentially involved in CNSL therapeutic action.     

Protein kinase C regulation of 12-lipoxygenase-mediated human platelet activation

Platelet activation is important in the regulation of hemostasis and thrombosis. Uncontrolled activation of platelets may lead to arterial thrombosis, which is a major cause of myocardial infarction and stroke. After activation, metabolism of arachidonic acid (AA) by 12-lipoxygenase (12-LOX) may play a significant role in regulating the degree and stability of platelet activation because inhibition of 12-LOX significantly attenuates platelet aggregation in response to various agonists. Protein kinase C (PKC) activation is also known to be an important regulator of platelet activity. Using a newly developed selective inhibitor for 12-LOX and a pan-PKC inhibitor, we investigated the role of PKC in 12-LOX-mediated regulation of agonist signaling in the platelet. To determine the role of PKC within the 12-LOX pathway, a number of biochemical endpoints were measured, including platelet aggregation, calcium mobilization, and integrin activation. Inhibition of 12-LOX or PKC resulted in inhibition of dense granule secretion and attenuation of both aggregation and αIIbβ(3) activation. However, activation of PKC downstream of 12-LOX inhibition rescued agonist-induced aggregation and integrin activation. Furthermore, inhibition of 12-LOX had no effect on PKC-mediated aggregation, indicating that 12-LOX is upstream of PKC. These studies support an essential role for PKC downstream of 12-LOX activation in human platelets and suggest 12-LOX as a possible target for antiplatelet therapy.     

基质金属蛋白酶-9与糖尿病肾病的相关性

目的观察大鼠糖尿病肾病(DN)发展过程中肾脏局部基质金属蛋白酶-9(MMP-9)表达的改变,分析其与DN的相关性。方法对16只链脲佐菌素(STZ)糖尿病大鼠模型分别于造模后第4、8周通过免疫组织化学染色法观察肾脏局部MMP-9的表达,以MMP-9平均积分吸光度(IDP)为观察指标。结果正常对照组第4、8周大鼠肾脏MMP-9表达(IDP分别为15.6±73.4,16.2±3.1)呈强阳性;实验组第4、8周大鼠肾脏MMP-9的表达(IDP分别为8.2±0.9,3.9±0.6)呈递减(P<0.01)。结论MMP-9表达减少是DN早期病理改变的重要原因之一。     

阿托伐他汀对急性脑梗死调脂及MMP-9影响的观察

目的 观察阿托伐他汀对急性脑梗死患者调脂及人单核细胞基质金属蛋白酶-9(MMP-9)的影响.方法 60例急性脑梗死患者给予阿托伐他汀20mg,口服,1次/d,疗程4周.观察治疗前后血脂和血清MMP-9的变化.结果 经阿托伐他汀治疗4周后,TC、LDL-C较治疗前均明显降低,HDL-C较治疗前明显升高,且明显优于对照组(P<0.05和0.01),血清MMP-9水平显著降低(P<0.01).结论 阿托伐他汀不仅具有调脂作用,还明显降低MMP-9的作用.     

阿托伐他汀对急性脑梗死调脂及MMP-9影响的观察

目的观察阿托伐他汀对急性脑梗死患者调脂及人单核细胞基质金属蛋白酶-9（MMP-9）的影响。方法60例急性脑梗死患者给予阿托伐他汀20mg,口服,1次/d,疗程4周。观察治疗前后血脂和血清MMP-9的变化。结果经阿托伐他汀治疗4周后,TC、LDL—C较治疗前均明显降低,HDL—C较治疗前明显升高,且明显优于对照组（P〈0．05和0．01）,血清MMP-9水平显著降低（P〈0．01）。结论阿托伐他汀不仅具有调脂作用,还明显降低MMP-9的作用。