Canine specific ELISA for coagulation factor VII

Kjelgaard‐Hansen, Mads; Tranholm, Mikael; Wiinberg, Bo; Clausen, Jes Thorn; Hansen, Jens; Nichols, Timothy C.; Kjalke, Marianne; Jensen, A. L.; Kristensen, Annemarie T.

doi:10.1016/j.tvjl.2010.11.010

Cited by 5 publications

(3 citation statements)

References 25 publications

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“…The discrepancy between the baseline activity and antigen levels in the FVII-G96E dogs is likely because of the lower sensitivity of the ELISA vs a PT clotting assay used. Our data are in good agreement with a previous report, 20 but the secretory defect of the FVII-G96E protein has only been demonstrated in vitro. 17 In order to directly confirm this specific defect in vivo, we used a polyclonal antibody that could detect both WT cFVII and cFVII-G96E ( Figure 1B).…”

Section: Fvii-g96e Dogs Are a Model Of Type I Fvii Deficiencysupporting

confidence: 93%

Sustained correction of FVII deficiency in dogs using AAV-mediated expression of zymogen FVII

Marcos‐Contreras

Smith

Bellinger³

et al. 2016

Blood

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• Dogs with an FVII G96E mutation (FVII-G96E) represent the most common human FVII mutation type and are ideal for testing new therapies.• cFVII gene delivery in FVII-G96E dogs via AAV at a dose effective in humans showed stable and clinically therapeutic FVII expression.Factor VII (FVII) deficiency is a rare autosomal recessive bleeding disorder treated by infusion of fresh-frozen plasma, plasma-derived FVII concentrates and low-dose recombinant activated FVII. Clinical data suggest that a mild elevation of plasma FVII levels (>10% normal) results in improved hemostasis. Research dogs with a G96E missense FVII mutation (FVII-G96E) have <1% FVII activity. By western blot, we show that they have undetectable plasmatic antigen, thus representing the most prevalent type of human FVII deficiency (low antigen/activity). In these dogs, we determine the feasibility of a gene therapy approach using liver-directed, adeno-associated viral (AAV) serotype 8 vector delivery of a canine FVII (cFVII) zymogen transgene. FVII-G96E dogs received escalating AAV doses (2E11 to 4.95E13 vector genomes [vg] per kg). Clinically therapeutic expression (15% normal) was attained with as low as 6E11 vg/kg of AAV and has been stable for >1 year (ongoing) without antibody formation to the cFVII transgene. Sustained and supraphysiological expression of 770% normal was observed using 4.95E13 vg/kg of AAV (2.6 years, ongoing). No evidence of pathological activation of coagulation or detrimental animal physiology was observed as platelet counts, D-dimer, fibrinogen levels, and serum chemistries remained normal in all dogs (cumulative 6.4 years). We observed a transient and noninhibitory immunoglobulin G class 2 response against cFVII only in the dog receiving the highest AAV dose. In conclusion, in the only largeanimal model representing the majority of FVII mutation types, our data are first to demonstrate the feasibility, safety, and long-term duration of AAV-mediated correction of FVII deficiency. (Blood. 2016;127(5):565-571)

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Section: Fvii-g96e Dogs Are a Model Of Type I Fvii Deficiencysupporting

confidence: 93%

Sustained correction of FVII deficiency in dogs using AAV-mediated expression of zymogen FVII

Marcos‐Contreras

Smith

Bellinger³

et al. 2016

Blood

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“…All haemostatic tests were performed at the Central Laboratory employing commercial reagents in a validated setup with an automated coagulometer (ACLTop 500, Instrumentation Laboratory) as previously described [ 24 ]: aPTT (SynthAFax, Instrumentation Laboratory); PT (RecombiPlasTin 2G, Instrumentation Laboratory); d-dimer (D-Dimer Single Tests, NycoCard READER II, Medinor A/S); fibrinogen (RecombiPlasTin 2G, Instrumentation Laboratory); AT (Liquid Antithrombin; Instrumentation Laboratory) and plasminogen (Plasminogen, Instrumentation Laboratory). A pooled sample of plasma from ten clinical healthy dogs was analyzed together with the patient samples and used as internal control.…”

Section: Methodsmentioning

confidence: 99%

Haemostatic alterations in a group of canine cancer patients are associated with cancer type and disease progression

et al. 2012

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BackgroundHaemostatic alterations are commonly detected in human and canine cancer patients. Previous studies have described haemostatic dysfunction in canine patients with haemangiosarcomas and carcinomas, and haemostasis has been assessed in dogs with various malignant and benign neoplasias. Few studies have addressed the effect of cancer type and progression of disease on the presence of haemostatic alterations in canine patients. The objective of the present study was to evaluate haemostatic variables of coagulation and fibrinolysis in a group of canine cancer patients, and to compare haemostatic changes to the cancer type and progression of disease.MethodsThe study population consisted of 71 dogs with malignant neoplasia presented to the University Hospital for Companion Animals, Faculty of Life Sciences, University of Copenhagen, Denmark. The study was designed as a prospective observational study evaluating the haemostatic function in canine cancer patients stratified according to type of cancer disease and disease progression. The coagulation response was evaluated by thromboelastrography (TEG), platelet count, activated partial thromboplastin time (aPTT), prothombin time (PT), fibrinogen and antithrombin (AT); and fibrinolysis by d-dimer and plasminogen.ResultsHypercoagulability was the most common haemostatic dysfunction found. Non mammary carcinomas had increased clot strength (TEG G), aPTT and fibrinogen compared to the other groups. When stratifying the patients according to disease progression dogs with distant metastatic disease exhibited significantly increased fibrinogen, and d-dimer compared to dogs with local invasive and local non-invasive cancers.ConclusionHypercoagulability was confirmed as the most common haemostatic abnormality in canine cancer patients and haemostatic dysfunction in canine cancer patients was found related to the cancer type and progression of disease. Increase in TEG G, aPTT and fibrinogen were observed in non-mammary carcinomas and were speculated to overall represent a proinflammatory response associated with the disease. Dogs with distant metastatic disease exhibited increased fibrinogen and d-dimer. Future studies are needed to elucidate the clinical importance of these results.

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“…Modifications included the use of canine FVII‐deficient substrate plasma from beagle dogs homozygous for the FVII G96E mutation [18], canine soluble TF truncated after residue 217 (cTF 1‐217 ) [11] at 40 ng mL −1 , and 0.05–2.0 ng mL −1 rcFVIIa as reference standard. FVII:Ag was measured in canine [19] and human (FVII EIA; Dako, Glostrup, Denmark) specific ELISAs, which measure total FVII:Ag (i.e. FVII as well as FVIIa antigen).…”

Section: Methodsmentioning

confidence: 99%

Pharmacokinetics, pharmacodynamics and safety of recombinant canine FVIIa in a study dosing one haemophilia A and one haemostatically normal dog

et al. 2011

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Summary Recombinant human FVIIa (rhFVIIa) corrects the coagulopathy in hemophilia A and B as well as FVII deficiency. This is also the case in dogs until canine anti-human FVIIa antibodies develop (~2 weeks). Recombinant canine factor VIIa (rcFVIIa), successfully over-expressed by gene transfer in haemophilia dogs, has provided long-term haemostasis (>2 years). However, pharmacokinetics (PK), pharmacodynamics (PD) and safety of rcFVIIa after pharmacological administration have not been reported. We therefore wanted to explore the safety, PK and PD of rcFVIIa in dogs. A pilot study was set up to evaluate the safety as well as PK and PD of rcFVIIa after a single intravenous dose of 270 μg kg−1 to one HA and one haemostatically normal dog and to directly compare rcFVIIa with rhFVIIa in these two dogs. Single doses of rcFVIIa and rhFVIIa were well tolerated. No adverse events were observed. Pharmacokinetic characteristics including half-life (FVIIa activity: 1.2–1.8 h; FVIIa antigen 2.8–3.7 h) and clearance were comparable for rcFVIIa and rhFVIIa. Kaolin-activated thromboelastography approached normal in the HA dog with the improvement being most pronounced after rcFVIIa. This study provided the first evidence that administering rcFVIIa intravenously is feasible, safe, well tolerated and efficacious in correcting the haemophilic coagulopathy in canine HA and that rcFVIIa exhibits pharmacokinetic characteristics comparable to rhFVIIa in haemophilic and haemostatically competent dogs. This strengthens the hypothesis that rcFVIIa can be administered to dogs to mimic the administration of rhFVIIa to humans.

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Canine specific ELISA for coagulation factor VII

Cited by 5 publications

References 25 publications

Sustained correction of FVII deficiency in dogs using AAV-mediated expression of zymogen FVII

Sustained correction of FVII deficiency in dogs using AAV-mediated expression of zymogen FVII

Haemostatic alterations in a group of canine cancer patients are associated with cancer type and disease progression

Pharmacokinetics, pharmacodynamics and safety of recombinant canine FVIIa in a study dosing one haemophilia A and one haemostatically normal dog

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