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Von Willebrand Factor and vWF Propeptide are Up‐regulated in Heparin‐Induced Thrombocytopenia
Author(s) -
Walenga Jeanine M,
Hoppensteadt Debra,
Davis Rachael,
Jeske Walter,
Escalante Vicki,
Conway Brooke,
Fareed Jawed
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.951.2
Subject(s) - von willebrand factor , platelet , von willebrand disease , protein precursor , medicine , endocrinology , heparin , immunology , chemistry , biochemistry , enzyme
Von Willebrand factor (vWF) plays a key role in platelet associated vascular disorders. vWF biosynthesis includes proteolytic cleavage of a 741‐residue propeptide (vWF‐PP) and the assembly of disulfide‐linked multimers. vWF‐PP levels is a marker of vWF synthesis. The vWF to vWF‐PP ratio is altered in individuals with low vWF synthesis. No reports are available on its levels in pathologic conditions where vWF levels are increased. We hypothesized that both vWF and vWF‐PP are up regulated in diagnostically confirmed heparin‐induced thrombocytopenia (HIT) patients (n=15). vWF antigen and vWF‐PP were measured using a commercially available kit (GTI, Waukesha, WI). Normal male and female citrated plasmas from 50 individuals were used as control. A commercially available ELISA method (Stago, Asnieres, France) was used to compare the vWF levels in the two groups. In comparison to the normals, the HIT patients showed a very high level of vWF (303 ± 91 vs 100 ± 61 U/mL). vWF‐PP was also higher in the HIT patients (318 ± 143 vs 92 ± 23 U/mL). Both groups showed a wide scatter in the levels of vWF and vWF‐PP. The ratio of vWF to vWF‐PP was not different between the two groups (1.04 ± 0.56 vs 1.21 ± 0.74) suggesting that the clearance of vWF‐PP is not altered in HIT syndrome. The vWF levels measured by the two methods were comparable. These studies suggest that vWF and its propeptides are up regulated in HIT syndrome but their clearance is normal.