Thrombin generation in children with sickle cell Anemia is Higher in the presence of platelets⋆ and ⋆

Cellular and plasma interactions underlie hypercoagulability in sickle cell anemia (SCA). In healthy adults, thrombin generation (TG), a biomarker of hypercoagulability, is similar in plasma with and without platelets. Studies investigating TG in SCA using platelet-poor plasma (PPP) show conflicting results. There are no studies in SCA simultaneously comparing TG using platelet rich plasma (PRP) and PPP.This prospective study compares TG in children with SCA, at steady state, in PPP versus PRP and investigates the association of predefined clinical variables with the difference between PRP and PPP. Our secondary aim was to investigate derangements in the protein C and S pathway measuring TG with and without thrombomodulin (TM).In forty-three paired samples from SCA patients, aged 2−15 years, TG in the presence of platelets was 5.9 % higher [1239 nmol/(min*L) (SD: 224.1) vs. 1151 nmol/(min*L) (SD 223.3); p = 0.026]. The difference was highest in the 6−10 year age group (9.5 %; SD 14.1) followed by the 2−5 year age group (5.4 %; SD 21.4). In a multiple linear regression model, age, gender, current use of hydroxyurea, degree of hemolysis and severity of pain crises were not predictive of the difference between PRP and PPP. In PPP, TG reduction after TM addition was 7.4 % (SD 16.8), signifying activated protein C resistance.In conclusion, TG in children with SCA aged 2−10 years is higher in the presence of platelets. TG using PRP along with TM addition may be a useful biomarker of hypercoagulability in this population.     

急性脑梗死患者体内血小板CD62P和sTLT-1的表达水平

目的大量研究表明血小板CD62P和sTLT-1能够促进动脉粥样硬化性血栓的形成,因此我们检测急性脑梗死患者体内血小板CD62P和sTLT-1的表达水平,以作为评价动脉粥样硬化性血栓形成的功能指标。方法选择急性脑梗死患者(发病时间≤7 d)102例作为病例组,同期选择来我科就诊的非急性脑梗死患者93例为对照组,采用流式细胞仪(flow cytometry,FCM)检测血小板CD62P的表达水平,用酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)检测血清中sTLT-1的表达水平。结果急性脑梗死组的血小板CD62P和sTLT-1的表达水平均明显高于对照组(P0.01),CD62P和sTLT-1的表达水平与急性脑梗死患者的神经功能缺损程度及梗死灶体积呈正相关;CD62P和sTLT-1之间呈直线正相关(r=0.247,P0.01);多元Logistic回归分析,CD62P和sTLT-1在校正其他相关危险因素后[CD62P(%)OR值=1.102,95%CI:1.062~1.143,P0.01;sTLT-1(pg/ml)OR值=1.004,95%CI:1.002~1.006,P0.01]。结论血小板CD62P和sTLT-1是脑梗死发病的危险因素,可能是急性脑梗死患者体内动脉粥样硬化性血栓形成的独立危险因素。     

Microparticle detection to guide platelet management for the reduction of platelet refractoriness in children – A study proposal

Microparticles have been shown to shed from a variety of viable cells as a consequence of inflammatory processes, activation or physical stress. Seventy to 90% of circulating microparticles are thought to be platelet-derived. The content of microparticles in blood collected from normal blood donors is highly variable and transfers into the final blood component. Elevated microparticle content (MPC) in donor blood might indicate an asymptomatic clinical condition of the donor which might affect the transfusion recipient, particularly pediatric patients. ThromboLUX is a new technology designed to routinely test biological samples for microparticle content. We compared MPC in platelet-rich plasma (PRP) of apheresis donors and the corresponding INTERCEPT-treated apheresis products (N = 24). The MPCs in donor and product samples were correlated (r = 0.74, P < 0.001). Microparticles were significantly reduced after plasma replacement and INTERCEPT treatment. These findings are supported by phase contrast microscopy. Platelet transfusions given to patients with fever or systemic inflammation are less efficacious. In addition, transfusing heterogeneous platelets – concentrates with high MPC and activated platelets – to patients whose immune systems are activated might tip them over a threshold and cause platelet refractoriness. Restricting prophylactic platelet transfusions to homogeneous products – concentrates with resting platelets and therefore low MPC – may reduce the risk of refractoriness in cancer patients, especially children with immature immunity. To test this hypothesis we introduce an evaluation protocol for platelet management, i.e., keeping a split inventory of homogeneous and heterogeneous platelets, and using only homogeneous platelets for prophylaxis as a strategy to reduce refractoriness.     

Molecules in seminal plasma related to platelets in preeclampsia

ObjectiveProstaglandins present in seminal fluid are actively involved in vascular and non-vascular smooth muscle maintenance, reproduction, and inflammatory processes. Seminal plasma contains molecules, such as oxylipins, which possess cell signaling functions. Several studies have shown that specific molecules in seminal fluid can increase passive diffusion, and cause interactions in the female reproductive tract. This may provoke a cascade of cellular and molecular changes in general health and certain diseases.This study examines the hypothesis that the molecules in seminal fluid are involved in platelet activity. The molecules diffuse through cells and membranes, affecting Hoxa 10, binding ganglioside pathways, and acting over platelet function. When these molecules are at low levels, they may trigger prothrombotic states, explaining the pathophysiology of haemostatic response, such as preeclampsia, and increased risk of cardiovascular disease.     

低值血小板总数与血小板分布密度的关系

目的探讨血小板总数与血涂片血小板分布密度的关系。方法取抗凝静脉血，经SysmexXE-2100全自动血细胞分析仅测定、SP—1000i推片机推片、染色后，选取血小板计数在90X]09／L以下的标本手工法计数，将手工法和血细胞分析仪法计数结果相近的标本的血涂片在显微镜下复检。观察连续的50个视野，记录每一个视野内血小板数量及零视野数目。结果150例血小板计数在90×109／L以下的标本中，血小板总数〈20×109／L，每油镜视野平均血小板数0—3个，零视野教目占20—50％；血小板总数在20～40×10^9／L，每油镜视野平均血小板数2—5个，零视野数目占10—16％；血小板总数在41～60×10^9／L，每油镜视野平均血小板数4—7个，零视野数目〈5％；血小板总数在61～90×10^9／L，每油镜视野平均血小板数5-10个，无零视野。结论对真性血小板降低（〈90X109／L）的标本，直接显微镜复检时，将每一视野血小板的数量和零视野数结合起来可较好地评估血小板数量。