含血小板凝血酶敏感蛋白的解聚蛋白样金属蛋白酶-1水平的检测及临床意义

目的:通过检测各类冠心病患者及健康人血清中含血小板凝血酶敏感蛋白的解聚蛋白样金属蛋白酶(ADAMTS)-1的水平,探讨ADAMTS-1水平测定在预测急性冠状动脉综合征(ACS)发生的价值.方法:选择40例急性心肌梗死(AMI)患者,50例不稳定型心绞痛(UAP)患者,40例稳定型心绞痛(SAP)患者,32例健康人,采集临床资料,取外周血,使用ELISA法检测血浆ADAMTS-1水平.结果:ADAMTS-1水平在冠心病组(100.71±37.06)μg/L显著高于对照组(47.04±11.79)μg/L,P<0.05.ADAMTS-1在SAP组(69.33±15.87)μg/L,UAP组(93.43±21.36)μg/L,AMI组(141.18±31.01)μg/L,显示ADAMTS-1水平有随冠心病临床症状的加重而增高的趋势,P<0.05.经多元logistic回归分析后结果显示,在所有入选者中(162例)及在冠心病组(130例)中,ADAMATS-1均与ACS独立相关.经ROC曲线分析,超敏C反应蛋白(HS-CRP)曲线下面积为92.9%(95%CI:88.6%～97.1%),ADAMTS-1曲线下面积为94.0%(95%CI:90.7%～97.3%).提示ADAMTS-1在预测ACS的发生方面不劣于甚至略优于HS-CRP.结论:ADAMTS-1可作为预测ACS发生的指标之一.     

Localization of blood proteins thrombospondin1 and ADAMTS13 to cerebral corpora amylacea

Corpora amylacea (CA) have long been described in aging brains and in patients with neurodegenerative conditions, but their origins have been debated. It has been proposed that CA represent collections of nervous system breakdown products that accumulate within astrocytic cytoplasm. In support of this, studies have shown that CA include glycosylated material, ubiquitin, and an assortment of proteins derived from neuronal cytoplasm. On the other hand, many of these proteins are not specifically localized to neurons or astrocytes; some components of CA, such as complement proteins, are most abundantly expressed outside the central nervous system. The characteristic predilection for CA to accumulate near vessels and ependyma suggests that proteins extravasated from blood or transudated from CSF may form a component of these structures. In this study, we report the immunohistochemical localization of blood and platelet proteins thrombospondin1 and ADAMTS13 in CA from aged individuals and patients with vascular dementia. Thrombospondin1 localized to neurons, but was most prominently localized to CA. An independent serum and platelet expressed protein, ADAMTS13, was found in CA in the same brain regions. In vitro analysis shows that thrombospondin1 and ADAMTS13 form complexes together in cells and in direct protein binding assays. We speculate that CA could result from a conglomeration of interacting proteins from degenerating neurons and from extravasated blood elements released after transient breakdown of the blood–brain barrier.     

Inhibitory autoantibodies against ADAMTS-13 in patients with thrombotic thrombocytopenic purpura bind ADAMTS-13 protease and may accelerate its clearance in vivo

BACKGROUND: Many patients with acquired thrombotic thrombocytopenic purpura (TTP) harbor autoantibodies that may bind and/or inhibit ADAMTS-13 proteolytic activity and accelerate its clearance in vivo. METHODS: To test this hypothesis, we determined ADAMTS-13 activity and antigen levels in parallel plasma samples from patients clinically diagnosed with TTP. Collagen binding, GST-VWF73 and FRETS-VWF73 assays were used to determine ADAMTS-13 activity and to detect inhibitory autoantibodies. Enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation plus Western blotting (IP/WB) were used to detect total anti-ADAMTS-13 IgG (inhibitory and non-inhibitory). RESULTS: Among 40 patients with TTP (21 idiopathic and 19 non-idiopathic), inhibitory autoantibodies were detected (by FRETS-VWF73) in 52% of idiopathic and 0% of non-idiopathic TTP patients. In contrast, non-inhibitory IgG autoantibodies were detected in 29% of idiopathic and 50% of non-idiopathic TTP patients. The concentration of inhibitory IgG autoantibody in idiopathic TTP patients was significantly higher than that of non-inhibitory IgG in either idiopathic or non-idiopathic TTP patients. Idiopathic TTP patients demonstrated significantly reduced ADAMTS-13 activity compared with non-idiopathic patients, but only slightly lower ADAMTS-13 antigen levels. Interestingly, patients with inhibitory autoantibodies exhibited significantly lower ADAMTS-13 antigen levels than those with only non-inhibitory IgG autoantibodies or no autoantibody. Serial plasma exchanges increased levels of ADAMTS-13 activity and antigen concurrently in patients with inhibitory autoantibodies. CONCLUSION: The identification of severe ADAMTS-13 deficiency and autoantibodies or inhibitors appears to be assay-dependent; the inhibitory IgG autoantibodies, in addition to binding and inhibiting ADAMTS-13 proteolytic activity, may accelerate ADAMTS-13 clearance in vivo.     

Calcium pentosan polysulfate and sodium pentosan polysulfate may be used to treat intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a major health problem world-wide, and several spinal disorders are closely associated with it. Although people have invested a great deal of time and effort, how to prevent and reverse the IDD for the researchers is still a difficult and hot issue. Intervertebral disc belongs to cartilage tissue, and IDD also is the cartilage degeneration disease. A large quantity of studies have shown that Calcium pentosan polysulfate (CaPPS) and sodium pentosan polysulfate (NaPPS) possess chondroprotective activities and play an important role in maintaining cartilage integrity. We reasonably hypothesize that NaPPS and CaPPS may be used to treat IDD. The possible mechanism may include that: (1) the significant effects of NaPPS and CaPPS in improving capillary blood flow could maintain nutritional supply to intervertebral disc, and preserve intervertebral disc tissue against degeneration; (2) CaPPS and NaPPS preserve cartilage integrity, proteoglycan synthesis, and improve cartilage biomechanical properties; (3) as the multifaceted exosite inhibitors of proteinases NaPPS and CaPPS strongly impede the activity and production of proteinases; (4) promotion of the balance between proteinases and TIMPs also may be involved in treating IDD; (5) NaPPS and CaPPS exhibit potent anti-inflammatory effects, and then reduce inflammation-induced IDD. If the hypothesis were conformed, the symptoms caused by IDD and its related diseases would be a corresponding alleviation or even disappearance, which could greatly alleviate the suffering of patients from disc degeneration diseases. Certainly, many roles of CaPPS and NaPPS, such as effectiveness, safety and side effects, need to be tested, and further works such as animal model and clinical trial, need to be done to prove this hypothesis.     

Analysis of Flavonoid‐Based Pharmacophores that Inhibit Aggrecanases (ADAMTS‐4 and ADAMTS‐5) and Matrix Metalloproteinases Through the Use of Topologically Constrained Peptide Substrates

Polyphenolic natural products from green tea and red wine have been identified as metalloproteinase inhibitors. Members from the flavonoid and stilbene families found to possess metalloproteinase inhibitory activities include (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol, but their minimally active pharmacophores have not been evaluated. The present study has examined compounds that are structural components of or structurally related to (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol for inhibition of aggrecanases and four representative matrix metalloproteinases. Piceatannol and pyrogallol were found to inhibit all aggrecanases and matrix metalloproteinases studied, indicating a crucial reliance on multiple hydroxyl groups for (?)‐epigallocatechin gallate, (?)‐epicatechin gallate and piceatannol activity. Differences in K_i values for pyrogallol as determined with two structurally distinct substrates indicated the likelihood that this compound binds in a non‐competitive modality. Further analysis showed that pyrogallol acts as an exosite inhibitor, consistent with the action of (?)‐epigallocatechin gallate. In contrast, piceatannol was shown to be a competitive binding inhibitor and showed no differences in apparent K_i values as determined by distinct substrates, illustrating the benefits of using two structurally distinct substrates to assist the analysis of protease inhibitors. The compounds identified here could be utilized to develop novel metalloproteinase probes or as fragment components of more active inhibitors.     

ABO blood types: influence on infarct size, procedural characteristics and prognosis

Introduction

Patients with non-O blood groups have higher plasma von Willebrand factor (vWF) levels than those with type O. vWF mediates platelet adhesion, aggregation and thrombosis. These considerations likely explain the prior observations that non-O patients have higher rates of arterial and venous thromboembolic events. However, the effect of blood group status on size of MI, procedural findings and outcomes after PCI for MI have not been reported.

Methods

We analyzed 1198 patients who underwent percutaneous coronary intervention for acute myocardial infarction between 10/03 and 8/06, and who had ABO blood group status and clinical follow-up.

Results and conclusions

Patients with O blood type were slightly older (62 ± 13 vs. 60 ± 13years; p = 0.017) had a higher prevalence of hypercholesterolemia (67% vs. 58%; p = 0.002), and had a higher burden of atherosclerosis with more vascular disease (17% vs. 13%; p = 0.017) and higher prevalence of previous PCI (22% vs. 17%; p = 0.025). Non-O blood group patients had larger infarcts as measured by median peak troponin (33 vs. 24; p = 0.037), total CK (721 vs. 532; p = 0.012) and CK-MB (101 vs. 68; p = 0.010). At PCI, non-O patients had increased visible thrombus and reduced TIMI flow pre-procedure. However, there were no differences in procedural success, in-hospital blood transfusion or occurrence of MACE at 1year follow-up. Our data demonstrate that non-O compared to O blood groups patients have higher thrombus burden despite less extensive atherosclerosis. Nevertheless, outcomes at 1year were similar.     

Remission in acute refractory and relapsing thrombotic thrombocytopenic purpura following rituximab is associated with a reduction in IgG antibodies to ADAMTS-13

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder and plasma exchange (PEX) remains the primary treatment modality. Twenty-five patients with acute refractory/relapsing idiopathic TTP received rituximab in conjunction with PEX because of progressive clinical disease or deterioration in laboratory parameters, despite intensive standard therapy. In relapsing TTP, rituximab was started if antibody to ADAMTS-13 (a disintegrin and metalloproteinase with thrombospondin motif-13) was demonstrated during previous episodes. All 25 patients attained complete clinical and laboratory remission in a median of 11 d after initiating rituximab. In 21 cases, ADAMTS-13 activity was within the normal range following rituximab. Inhibitors were detected in 24/25 patients by mixing studies and/or immunoglobulin G (IgG) antibodies to ADAMTS-13 pre-rituximab. There was no evidence of inhibitors and/or IgG activity <10% in 23/25 patients following rituximab. In acute refractory cases, the median number of PEX pre-rituximab and following the first rituximab infusion was 13 and 9, respectively. There have been no infectious complications, despite low CD 19 levels and no relapses. In patients with acute refractory/relapsing idiopathic TTP, rituximab appears to be a safe, effective, targeted therapy with a significant reduction in the requirement for PEX.     

Modulators of intraplatelet calcium concentration affect the binding of thrombospondin to blood platelets in healthy donors and patients with type 2 diabetes mellitus

Thrombospondin (TSP), which is secreted from alpha-granules of activated platelets, binds to its surface receptor (CD36) in the presence of Ca2+. OBJECTIVES: We monitored how the modulation of intraplatelet Ca2+ affects TSP binding to CD36 on platelets from healthy donors and patients with type 2 diabetes mellitus. We also aimed to verify whether the impaired Ca2+ mobilisation in diabetes influences TSP binding upon the pharmacological modulation of calcium transport. METHODS: Whole blood cytometry was used to monitor TSP release/binding and CD36 presentation in platelets from 28 type 2 patients and 33 healthy donors. Results: No significant changes in TSP and CD36 levels were revealed between the groups in circulating platelets and TRAP-, collagen- or thrombin-activated platelets. In healthy donors, 1 microM thapsigargin (TG) elevated the TRAP-activated TSP binding (by up to 50%, p<0.001), 5 mM EGTA reversed the effect (by up to 85%, p<0.001), and overcame the effect of TG when used together. Less profoundly expressed effects occurred in the NIDDM group. In both groups TG increased the presentation of CD36 in TRAP-stimulated platelets (p<0.05), whereas EGTA lowered the TRAP-stimulated increase in CD36 (p<0.001). The inhibition of CD36 by EGTA was stronger in healthy volunteers (41% vs. 32%, respectively, p<0.05), whereas the activation by TG was higher in the NIDDM group (11% vs. 27%, p<0.05). When acting together the suppressive effects of EGTA on TG-dependent Ca2+ mobilisation were much attenuated in diabetic subjects (p<0.05). Conclusion: Both the release of TSP and CD36 presentation are under the influence of agents modulating intracellular Ca2+. Diabetic platelets seem more vulnerable to the releasers of cytosolic [Ca2+] and more resistant to the blockers of cytosolic [Ca2+] mobilisation.