脑血栓患者体外血栓形成观察：（附120例报告）

测定120例脑血栓患者和132例健康人体外血栓各值,并结合病情轻重及蝮蛇抗栓酶治疗进行分析.结果:患者组体外血栓各值均高于健康人(P<0.001);病情不同,其体外血栓各值间有显著差异(P<0.002—0.001);治疗后体外血栓各位明显下降(P<0.001).表明体外血栓结果对脑血栓患者病情判定及疗效观察均有一定意义。     

老年腰椎间盘突出症患者术后下肢深静脉血栓形成的影响因素及术前D-D、TM、Leptin联合应用的预测价值

摘要 目的：分析老年腰椎间盘突出症（LDH）患者术后下肢深静脉血栓形成（LDVT）的影响因素并探讨术前D-二聚体（D-D）、血栓调节蛋白（TM）、瘦素（Leptin）联合应用的预测价值。方法：选取2020年1月～2021年12月广州医科大学附属第三医院收治的412例接受腰椎椎间融合术（LIF）老年LDH患者,根据术后是否发生LDVT将其分为LDVT组和非LDVT组。收集老年LDH患者临床资料,采用酶联免疫吸附法检测术前血清D-D、TM、Leptin水平。采用多因素Logistic回归分析老年LDH患者LIF术后LDVT的影响因素,采用受试者工作特征（ROC）曲线分析术前血清D-D、TM、Leptin水平对老年LDH患者LIF术后LDVT的预测价值。结果：412例老年LDH患者LIF术后LDVT发生率为21.12%（87/412）。多因素Logistic回归分析显示,年龄增加、体质指数≥24 kg/m²、卧床时间≥7 d、D-D升高、TM升高、Leptin升高为老年LDH患者LIF术后LDVT的独立危险因素（P＜0.05）。ROC曲线分析显示,术前血清D-D、TM、Leptin水平单独与联合预测老年LDH患者LIF术后LDVT的曲线下面积分别为0.766、0.760、0.767、0.894,联合预测的曲线下面积大于D-D、TM、Leptin单独预测。结论：老年LDH患者LIF术后LDVT发生与年龄、体质指数、卧床时间和D-D、TM、Leptin有关,术前血清D-D、TM、Leptin水平联合预测老年LDH患者LIF术后LDVT的价值较高。     

血栓分子标志物与急性缺血性脑卒中病情严重程度及溶栓预后的相关性

摘要 目的：探究血栓分子标志物[血栓调节蛋白（TM）、凝血酶-抗凝血酶Ⅲ复合物（TAT）、纤溶酶-α2纤溶酶抑制剂复合物（PIC）、组织型纤溶酶原激活剂-抑制剂1复合物（t-PAIC）]与急性缺血性脑卒中(AIS)病情严重程度及溶栓预后的相关性。方法：选取2020年 7月至2022年6月我院神经内科收治的AIS患者120例为研究组,根据患者NIHSS评分为轻症组（n=48）、中症组（n=52）及重症组（n=20）;NIHSS评分升高组（n=50）和降低组（n=70）。同期选择我院查体中心查体的健康人群为对照组(n=30)。对比观察组和对照组、不同严重程度和不同预后患者外周血血栓分子标志物水平差异。采用Pearson相关分析法分析AIS患者外周血血栓分子标志物水平与病情严重程度及预后的相关性。利用ROC曲线评估外周血血栓分子标志物水平对AIS患者预后的预测价值。结果：AIS组患者外周血TM、TAT、PIC及t-PAIC水平明显高于对照组,差异有统计意义（P＜0.01）。重症组患者外周血TM、TAT、PIC及t-PAIC水平明显高于中症组及轻症组,中症组患者血清TM、TAT、PIC及t-PAIC水平明显高于轻症组,差异有统计意义（P＜0.01）。NIHSS评分升高组患者外周血TM、TAT、PIC及t-PAIC水平明显高于NIHSS评分降低组,差异有统计意义（P＜0.01）。外周血TM、TAT、PIC及t-PAICt水平与NIHSS评分呈正相关（r分别为0.326、0.513、0.124和0.417,P均＜0.05）。外周血TM、TAT、PIC及t-PAIC水平预估AIS患者预后的AUC 分别为 0. 737,0.850,0.762和0.712。其中TAT预估AIS患者预后的AUC、敏感度和特异性均最高。结论：AIS患者外周血TM、TAT、PIC及t-PAIC水平明显高于健康人群,可随病情严重程度及预后情况的变化而变化,其在病情评估及溶栓预后预测中具有指导价值。     

Direct observation of membrane tethers formed during neutrophil attachment to platelets or P-selectin under physiological flow

Adhesion and subsequent aggregation between neutrophils and platelets is dependent upon the initial binding of P-selectin on activated platelets to P-selectin glycoprotein ligand 1 (PSGL-1) on the microvilli of neutrophils. High speed, high resolution videomicroscopy of flowing neutrophils interacting with spread platelets demonstrated that thin membrane tethers were pulled from neutrophils in 32 +/- 4% of the interactions. After capture by spread platelets, neutrophil membrane tethers (length of 5.9 +/- 4.1 microm, n = 63) were pulled at an average rate of 6-40 microm/s as the wall shear rate was increased from 100-250 s(-1). The average tether lifetime decreased significantly (P < 0.001) from 630 to 133 ms as the shear rate was increased from 100 s(-1) (F(bond) = 86 pN) to 250 s(-1) (F(bond) = 172 pN), which is consistent with P-selectin/PSGL-1 bond dynamics under stress. Tether formation was blocked by antibodies against P-selectin or PSGL-1, but not by anti-CD18 antibodies. During neutrophil rolling on P-selectin at 150 s(-1), thin membrane tethers were also pulled from the neutrophils. The characteristic jerking motion of the neutrophil coexisted with tether growth (8.9 +/- 8.8 microm long), whereas tether breakage (average lifetime of 3.79 +/- 3.32 s) caused an acute jump in the rolling velocity, proving multiple bonding in the cell surface and the tether surface contact area. Extremely long membrane tethers (>40 microm) were sometimes pulled, which detached in a flow-dependent mechanism of microparticle formation. Membrane tethers were also formed when neutrophils were perfused over platelet monolayers. These results are the first visualization of the often hypothesized tethers that shield the P-selectin/PSGL-1 bond from force loading to regulate neutrophil rolling during inflammation and thrombosis.     

Hydrogen sulfide attenuates ferric chloride-induced arterial thrombosis in rats

Hydrogen sulfide (H₂S) is a novel gaseous transmitter, regulating a multitude of biological processes in the cardiovascular and other systems. However, it remains unclear whether it exerts any effect on arterial thrombosis. In this study, we examined the effect of H₂S on ferric chloride (FeCl₃)-induced thrombosis in the rat common carotid artery (CCA). The results revealed a decrease of the H₂S-producing enzyme cystathionine γ-lyase (CSE) expression and H₂S production that persisted until 48?h after FeCl₃ application. Intriguingly, administration with NaHS at appropriate regimen reduced the thrombus formation and enhanced the blood flow, accompanied with the alleviation of CSE and CD31 downregulation, and endothelial cell apoptosis in the rat CCA following FeCl₃ application. Moreover, the antithrombotic effect of H₂S was also observed in Rose Bengal photochemical model in which the development of thrombosis is contributed by oxidative injury to the endothelium. The in vitro study demonstrated that the mRNA and protein expression of CSE, as well as H₂S production, was decreased in hydrogen peroxide (H₂O₂)-treated endothelial cells. Exogenous supplement of NaHS and CSE overexpression consistently alleviated the increase of cleaved caspase-3 and endothelial cell damage caused by H₂O₂. Taken together, our findings suggest that endogenous H₂S generation in the endothelium may be impaired during arterial thrombosis and that modulation of H₂S, either exogenous supplement or boost of endogenous production, may become a potential venue for arterial thrombosis therapy.     

Store-operated calcium entry in thrombosis and thrombo-inflammation

Cytosolic free calcium (Ca²⁺) is a second messenger regulating a wide variety of functions in blood cells, including adhesion, activation, proliferation and migration. Store-operated Ca²⁺ entry (SOCE), triggered by depletion of Ca²⁺ from the endoplasmic reticulum, provides a main mechanism of regulated Ca²⁺ influx in blood cells. SOCE is mediated and regulated by isoforms of the ion channel proteins ORAI and TRP, and the transmembrane Ca²⁺ sensors stromal interaction molecules (STIMs), respectively. This report provides an overview of the (patho)physiological importance of SOCE in blood cells implicated in thrombosis and thrombo-inflammation, i.e. platelets and immune cells. We also discuss the physiological consequences of dysregulated SOCE in platelets and immune cells and the potential of SOCE inhibition as a therapeutic option to prevent or treat arterial thrombosis as well as thrombo-inflammatory disease states such as ischemic stroke.     

Update on pathological platelet activation in coronary thrombosis

Although coronary thrombosis (CT) is integral to cardiovascular outcomes, the underlying pathophysiological mechanisms remain unclear. CT may occur in case of atherosclerotic plaque erosion/rupture, or even after stenting implantation. Platelets (PLT) activation is the keystone of atherothrombosis and depends on many dysregulated elements, including endothelial dysfunction, oxidized lipoproteins, and immune response. Besides the classical view of PLT as an effector of hemostatic response, a new repertoire of PLT activities is emerging. PLT lipidome oxidation is a self-maintaining process which promotes PLT reactivity, coagulation cascade, and inflammatory cell activation. PLT-innate immune cell interaction is also sustained by neutrophil extracellular traps and NLRP3 inflammasome pathways. Other noteworthy emerging mechanisms are implicated in the crosstalk between PLT and surrounding cells. Especially, microvesicles (MVs) released from PLT may extend their signaling network far beyond the classical cell−cell interactions. Moreover, the recognition of noncoding RNA in PLT MVs introduce another layer of complexity in terms of intercellular signaling by a direct regulation of messenger RNA profile and gene expression in the recipient cells. The aim of this narrative review is to update the recent advance in CT and intracoronary stent thrombosis, including causal factors and potential translation of experimental evidence into the clinical setting.     

Controversies and future perspectives of antiplatelet therapy in secondary stroke prevention

Antiplatelet agents are a cornerstone in the treatment of acute arterial thrombotic events and in the prevention of thrombus formation. However, existing antiplatelet agents (mainly aspirin, the combination of aspirin and dipyridamole and clopidogrel) reduce the risk of vascular events only by about one quarter compared with placebo. As a consequence, more efficacious antiplatelet therapies with a reduced bleeding risk are needed. We give an overview of several new antiplatelet agents that are currently investigated in secondary stroke prevention: adenosine 5′-diphosphonate receptor antagonists, cilostazol, sarpogrelate, terutroban and SCH 530348. There are unique features in secondary stroke prevention that have to be taken into account: ischaemic stroke is a heterogeneous disease caused by multiple aetiologies and the blood–brain barrier is disturbed after stroke which may result in a higher intracerebral bleeding risk. Several small randomized trials indicated that the combination of aspirin and clopidogrel might be superior to antiplatelet monotherapy in the acute and early post-ischaemic phase. There is an ongoing debate about antiplatelet resistance. Decreasing response to aspirin is correlated independently with an increased risk of cardiovascular events. However, there is still no evidence from randomized trials linking aspirin resistance and recurrent ischaemic events. Similarly, randomized trials have not demonstrated a clinical significantly decreased antiplatelet effect by the concomitant use of clopidogrel and proton pump inhibitors. Nevertheless, a routine use of this drug combination is not recommended.     

Proteomic profiling of platelet signalling

Platelets play a crucial role in hemostasis; activating and aggregating to arrest bleeding following vascular injury. Platelet activation is a complex and dynamic process, involving the co-ordination of numerous receptors to initiate shape change and aggregation. Under pathological conditions, alterations in the normal platelet response can favor a prothrombotic state and increase the risk of acute coronary syndromes (ACS). Receptor stimulation and the tyrosine phosphorylation of key signaling molecules underpin platelet activation in both hemostasis and cardiovascular disease. A lack of nucleus and low mRNA levels makes protein function the primary focus of platelet research. Advancements in proteomic technologies now allow for comprehensive analysis of the platelet proteome and its associated post-translational modifications. In this review, recent applications of proteomics in platelet signaling studies are discussed with particular focus on the elucidation of novel phosphorylation events following receptor activation.