Structure-function of platelet glycoprotein Ib-IX.

Structure-function of platelet glycoprotein Ib-IX. J Thromb Haemost. 2020 Jul 31;: Authors: Quach ME, Li R Abstract The glycoprotein (GP)Ib-IX receptor complex plays a critical role in platelet physiology and pathology. Its interaction with von Willebrand factor (VWF) on the subendothelial matrix instigates platelet arrest at the site of vascular injury, and is vital to primary hemostasis. Its reception to other ligands and counter-receptors in the blood stream also contribute to various processes of platelet biology that are still being discovered. While its basic composition and its link to congenital bleeding disorders were well documented and firmly established more than 25 years ago, recent years have witnessed critical advances in the organization, dynamics, activation, regulation and functions of the GPIb-IX complex. This review summarizes important findings and identifies questions that remain about this unique platelet mechanoreceptor complex. PMID: 32735697 [PubMed - as supplied by publisher]
Source: Thrombosis and Haemostasis - Category: Hematology Authors: Tags: J Thromb Haemost Source Type: research

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AbstractThe relation of device related thrombosis (DRT) and major bleeding after left atrial appendage closure (LAAC) to laboratory thrombosis and hemostasis markers has not been studied. We performed a prospective case control study to identify clinical characteristics and laboratory markers in patients who developed DRT and major bleeding following WATCHMAN LAAC. Thromboelastography, platelet aggregation (PA), urinary 11-dehydrothromboxane B2 (UTX), fibrinogen,d-dimer, thrombin time and von Willebrand factor activity were determined at baseline, immediately following, and at 45 and 180  days post-LAAC (n =&th...
Source: Journal of Thrombosis and Thrombolysis - Category: Hematology Source Type: research
Abstract Von Willebrand disease (VWD) is the most common inherited bleeding disorder and is mainly caused by dominant-negative mutations in the multimeric protein von Willebrand factor (VWF). These mutations may either result in quantitative or qualitative defects in VWF. VWF is an endothelial protein that is secreted to the circulation upon endothelial activation. Once secreted, VWF multimers bind platelets and chaperone coagulation factor VIII in the circulation. Treatment of VWD focuses on increasing VWF plasma levels, but production and secretion of mutant VWF remain uninterrupted. Presence of circulating muta...
Source: Thrombosis and Haemostasis - Category: Hematology Authors: Tags: Thromb Haemost Source Type: research
Semin Thromb Hemost DOI: 10.1055/s-0040-1714202There is increasing evidence that portal hypertension plays a major role in bleeding risk during orthotopic liver transplantation (OLT). We investigated the association between preoperative blood levels of von Willebrand factor (VWF) and soluble CD163 (sCD163), which are established markers of portal hypertension, and blood loss and transfusion requirements during OLT. We measured levels of VWF and sCD163 in preoperative serum samples of 168 adult patients undergoing a primary OLT between 1998 and 2012. Preoperative levels of VWF and sCD163 correlated with the model of end-sta...
Source: Seminars in Thrombosis and Hemostasis - Category: Hematology Authors: Tags: Review Article Source Type: research
CONCLUSION:  A PK model was developed, describing VWF activity versus time profile after desmopressin administration in patients with VWD or low VWF. Interpatient variability in response was quantified and partially explained. This model is a starting point toward more accurate prediction of desmopressin dosing effects in VWD. PMID: 32746466 [PubMed - as supplied by publisher]
Source: Thrombosis and Haemostasis - Category: Hematology Authors: Tags: Thromb Haemost Source Type: research
The deficiency or abnormal activity of von Willebrand factor, a multi-adhesive protein which binds platelets to exposed subendothelium and carries factor VIII in circulation, is responsible for von Willebrand disease, the most frequent inherited bleeding disorder. Clinical symptoms are characterized by mucous membrane and soft tissue bleeding, bleeding after surgery and rarely joint and gastrointestinal bleeding. Intriguingly, also factor VIII, the protein deficient in hemophilia A, may be variably reduced because VWF stabilizes it into circulation.
Source: Thrombosis Research - Category: Hematology Authors: Tags: Review Article Source Type: research
This study also emphasized the need for inclusion of the VWF:FVIIIB in suspected hemophilia A to achieve an optimal treatment strategy.
Source: Blood Coagulation and Fibrinolysis - Category: Hematology Tags: ORIGINAL ARTICLES Source Type: research
CONCLUSION:  MLBCs and CT-ADP > 180 seconds were identified as predictors for ischemic stroke or TIA. The present study suggests that the defects of HMW multimers of the VWFs may contribute not only to bleeding events but also to thrombotic events. PMID: 32726854 [PubMed - as supplied by publisher]
Source: Thrombosis and Haemostasis - Category: Hematology Authors: Tags: Thromb Haemost Source Type: research
AbstractAimsBleeding is a serious complication in patients with continuous ‐flow left ventricular assist device (CF‐LVAD). Acquired von Willebrand syndrome (AVWS; type 2A) develops because of high shear stress inside the pumps and is a cause of bleeding complication. Although von Willebrand factor (vWF) multimer analysis is useful for diagnosing AVWS, it is only perfor med in specialized research institutes. A novel microchip flow chamber system, the total thrombus‐formation analysis system (T‐TAS), is a point‐of‐care system to evaluate the thrombus‐formation process and useful for monitoring platelet thrombu...
Source: ESC Heart Failure - Category: Cardiology Authors: Tags: Short Communication Source Type: research
CONCLUSIONS: Our findings suggest that acquired von Willebrand syndrome can develop in patients with hitherto-undiagnosed inherited von Willebrand disease. Since von Willebrand disease is the most common bleeding disorder, this possibility should be considered in aortic stenosis patients-especially those with a more severe bleeding history and more disrupted VWF laboratory patterns-because they risk hemorrhage during aortic valve replacement. PMID: 32640909 [PubMed - as supplied by publisher]
Source: Arteriosclerosis, Thrombosis and Vascular Biology - Category: Cardiology Authors: Tags: Arterioscler Thromb Vasc Biol Source Type: research
Abstract von Willebrand disease (VWD) is a quantitative or qualitative defect in von Willebrand factor (VWF) resulting in mucocutaneous bleeding symptoms and hemorrhage following hemostatic challenges, such as trauma or surgery. VWD-specific therapy, DDAVP (1-desamino-8-D-arginine vasopressin) and VWF concentrates, is necessary periprocedurally to ensure adequate hemostasis. The aging VWD patient may complicate this matter. The plasma concentration of many coagulation proteins, including VWF, increases with age. While it has been established that VWF levels increase with age in a healthy population, emerging resea...
Source: Thrombosis and Haemostasis - Category: Hematology Authors: Tags: Thromb Haemost Source Type: research
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