scholarly journals Utility of factor VIII and factor VIII to von Willebrand factor ratio in identifying 277 unselected carriers of hemophilia A

2017 ◽  
Vol 92 (6) ◽  
pp. E94-E96 ◽  
Author(s):  
Veerle Labarque ◽  
Vanitha Perinparajah ◽  
Vanessa Bouskill ◽  
Ann Marie Stain ◽  
Cindy Wakefield ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Hemophilia A ◽  
Factor Ratio ◽  
Von Willebrand ◽  
Willebrand Factor

A novel cause of mild/moderate hemophilia A: mutations scattered in the factor VIII C1 domain reduce factor VIII binding to von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 958-965 ◽  
Author(s):  
Marc Jacquemin ◽  
Renaud Lavend'homme ◽  
Abdellah Benhida ◽  
Beatrijs Vanzieleghem ◽  
Roseline d'Oiron ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Cho Cells ◽  
Hemophilia A ◽  
Chinese Hamster ◽  
Expression Vectors ◽  
Scatchard Analysis ◽  
C1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.

scholarly journals Native-Like Aggregates of Factor VIII Are Immunogenic in von Willebrand Factor Deficient and Hemophilia a Mice

2012 ◽  
Vol 101 (6) ◽  
pp. 2055-2065 ◽  
Author(s):  
Dipak S. Pisal ◽  
Matthew P. Kosloski ◽  
C. Russell Middaugh ◽  
Richard B. Bankert ◽  
Sathy V. Balu-iyer
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Hemophilia A ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals The roles of von Willebrand factor and factor VIII in arterial thrombosis: studies in canine von Willebrand disease and hemophilia A

Blood ◽  
1993 ◽  
Vol 81 (10) ◽  
pp. 2644-2651 ◽  
Author(s):  
TC Nichols ◽  
DA Bellinger ◽  
RL Reddick ◽  
SV Smith ◽  
GG Koch ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Arterial Thrombosis ◽  
Hemophilia A ◽  
Full Range ◽  
Von Willebrand Disease ◽  
Arterial Stenosis ◽  
Canine Plasma ◽  
Von Willebrand ◽  
Willebrand Factor

We have studied the roles of von Willebrand factor (vWF) and factor VIII in arterial thrombosis in four canine phenotypes: normal (n = 6), hemophilia A (n = 11), von Willebrand disease (vWD) (n = 9), and hemophilia A/vWD (n = 1). vWF activity was determined by botrocetin- induced agglutination of fixed human platelets and vWF antigen (vWF:Ag) by Laurell electroimmunoassay and crossed immunoelectrophoresis. Plasma from normal dogs and those with hemophilia A had vWF activity, vWF:Ag, and a full range of vWF:Ag multimers on gel electrophoresis equivalent to normal canine plasma pool. Platelet cytosol contents were isolated by freezing and thawing, triton X-100 solubilization, or sonication of washed platelets with and without protease inhibitors and inhibitors of platelet activation. Washed platelets were also stimulated with calcium ionophore and MgCl2. There was no measurable vWF activity or vWF:Ag in platelet lysates or releasates in any dog regardless of phenotype. All dogs were studied using a standard arterial stenosis and injury procedure to induce arterial thrombosis. Thromboses were detected by cyclic reductions in Doppler blood flow velocity. Vessels were examined by light and scanning electron microscopy. Thrombosis developed in the arteries of normal (9 of 10) and hemophilia A dogs (16 of 16) but in none of the vWD dogs (0 of 10). Infusion of canine vWF cryoprecipitate into vWD dogs markedly shortened bleeding time but did not support thrombosis as seen in dogs with vWF in the plasma and subendothelium. Thrombosis, then, fails to occur when vWF is absent from the plasma and subendothelial compartments or present only in the plasma compartment. These data are consistent with the hypothesis that vWF in the plasma and subendothelium supports thrombosis. Neither plasma FVIII nor platelet vWF is essential for thrombosis in this model.

scholarly journals A novel cause of mild/moderate hemophilia A: mutations scattered in the factor VIII C1 domain reduce factor VIII binding to von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 958-965 ◽  
Author(s):  
Marc Jacquemin ◽  
Renaud Lavend'homme ◽  
Abdellah Benhida ◽  
Beatrijs Vanzieleghem ◽  
Roseline d'Oiron ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Cho Cells ◽  
Hemophilia A ◽  
Chinese Hamster ◽  
Expression Vectors ◽  
Scatchard Analysis ◽  
C1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.

scholarly journals BIVV001, a new class of factor VIII replacement for hemophilia A that is independent of von Willebrand factor in primates and mice

Blood ◽  
2020 ◽  
Vol 135 (17) ◽  
pp. 1484-1496 ◽  
Author(s):  
Ekta Seth Chhabra ◽  
Tongyao Liu ◽  
John Kulman ◽  
Susannah Patarroyo-White ◽  
Buyue Yang ◽  
...  
Keyword(s):  
Protein Engineering ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Half Life ◽  
Hemophilia A ◽  
Severe Hemophilia ◽  
New Class ◽  
Pharmacokinetic Properties ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Factor VIII (FVIII) replacement products enable comprehensive care in hemophilia A. Treatment goals in severe hemophilia A are expanding beyond low annualized bleed rates to include long-term outcomes associated with high sustained FVIII levels. Endogenous von Willebrand factor (VWF) stabilizes and protects FVIII from degradation and clearance, but it also subjects FVIII to a half-life ceiling of ∼15 to 19 hours. Increasing recombinant FVIII (rFVIII) half-life further is ultimately dependent upon uncoupling rFVIII from endogenous VWF. We have developed a new class of FVIII replacement, rFVIIIFc-VWF-XTEN (BIVV001), that is physically decoupled from endogenous VWF and has enhanced pharmacokinetic properties compared with all previous FVIII products. BIVV001 was bioengineered as a unique fusion protein consisting of a VWF-DʹD3 domain fused to rFVIII via immunoglobulin-G1 Fc domains and 2 XTEN polypeptides (Amunix Pharmaceuticals, Inc, Mountain View, CA). Plasma FVIII half-life after BIVV001 administration in mice and monkeys was 25 to 31 hours and 33 to 34 hours, respectively, representing a three- to fourfold increase in FVIII half-life. Our results showed that multifaceted protein engineering, far beyond a few amino acid substitutions, could significantly improve rFVIII pharmacokinetic properties while maintaining hemostatic function. BIVV001 is the first rFVIII with the potential to significantly change the treatment paradigm for severe hemophilia A by providing optimal protection against all bleed types, with less frequent doses. The protein engineering methods described herein can also be applied to other complex proteins.

Immune Tolerance Resulting in a Dramatic Clinical Improvement in a High-Responding Inhibitor Hemophilia A Patient Using Immunosuppression with Mycofenolate Mofetil and a Factor VIII Concentrate Containing Von Willebrand Factor.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3220-3220
Author(s):  
Thierry Lambert ◽  
Cécile Goujard ◽  
Anne Rafowicz ◽  
Benoît Guillet ◽  
Yacine Taoufik ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Factor Viii ◽  
Clinical Improvement ◽  
Von Willebrand Factor ◽  
Immune Tolerance ◽  
Hemophilia A ◽  
Inhibitor Level ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract A 40 year-old Caucasian patient with severe familial hemophilia A (FVIII <1%) related to an intron 22 inversion developed at the age of 2 a high-responding inhibitor. His elder brother also suffers from hemophilia A with high-responding inhibitor. Until 2000, the patient had been treated either using activated prothrombin complex concentrates (Autoplex® and Feiba®) or factor VIII (FVIII) concentrates of human (1983) and porcine origin (1992), resulting respectively in an inhibitor level rise at 360 Bethesda Units (BU) and 1800 BU. Between 2000 and 2003, the patient received exclusively recombinant activated Factor VII (NovoSeven®), and his inhibitor levels stabilized at a plateau of 15–20 BU. Between 2000 and 2003, several life or function threatening bleeding episodes occurred, such as hematomas of the iliopsoas muscles, spinal cord hematoma with transient paraplegia. Furthermore, due to hemarthroses the patient was confined to a wheelchair. Given the major impact of the inhibitor on the patient’s functional prognosis, life expectancy and quality of life, immune tolerance (IT) treatment was initiated, despite the high risk of failure (initiation 36 years after inhibitor onset, historical peak titer at 1800 BU, persistence of a plateau of 15–20 BU despite the absence of any stimulation with FVIII within the 3 last years). It started with an immunosuppressive drug, mycofenolate mofetil (Cellcept®) first given in may 2003 (no effect alone on inhibitor titer) and then in November 2003, infusions of a FVIII concentrate rich in von Willebrand factor, Factane® (LFB, Les Ulis, France) using 12,000 IU/day (150 IU/kg) of FVIII. The inhibitor peaked at 520 BU on D19 and was 0.5 BU by May 2004. Thus, the FVIII dosage was progressively reduced to 7000 IU/day. In July 2005, 24 hours after a 7000 IU FVIII infusion, inhibitor level was 0.7 BU, the residual FVIII level was 0.04IU/ml with a recovery of FVIIIc of 1.37%/IU/kg infused and a half-life of 4.9 hours. No significant change in the immunophenotype of peripheral blood lymphocytes was observed during this course. The patient’s quality of life was dramatically improved, with no hospitalization required and no bleeding episode observed within the 16 last months. The patient can now stand and has returned to his previous social activities. These preliminary results show that this IT treatment, performed despite a high theoretical risk of failure, resulted in this patient in a dramatic clinical improvement, even though biological criteria of success have not yet been achieved. The respective roles of the type of FVIII concentrate, and of immunosuppression remain to be assessed, as well as the cost/benefit analysis on a longer follow-up period.

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