The severe spontaneous bleeding phenotype in a novel hemophilia A rat model is rescued by platelet FVIII expression. Blood Adv 2020 Jan 14;4(1):55-65
Date
01/04/2020Pubmed ID
31899798Pubmed Central ID
PMC6960468DOI
10.1182/bloodadvances.2019000944Scopus ID
2-s2.0-85078174834 (requires institutional sign-in at Scopus site) 11 CitationsAbstract
Previous studies have shown that platelet-specific factor VIII (FVIII) expression (2bF8) restores hemostasis and induces immune tolerance in hemophilia A (HA) mice even with preexisting inhibitors. Here we investigated for the first time whether platelet FVIII expression can prevent severe spontaneous bleeding in rat HA, a model mimicking the frequent spontaneous bleeding in patients with severe HA. A novel FVIII-/- rat model in a Dahl inbred background (Dahl-FVIII-/-) with nearly the entire rat FVIII gene inverted was created by using a CRISPR/Cas9 strategy. There was no detectable FVIII in plasma. Spontaneous bleeding in the soft tissue, muscles, or joints occurred in 100% of FVIII-/- rats. Sixty-one percent developed anti-FVIII inhibitors after ≥2 doses of recombinant human FVIII infusion. However, when 2bF8 transgene was crossed into the FVIII-/- background, none of the resulting 2bF8tg+FVIII-/- rats (with platelet FVIII levels of 28.26 ± 7.69 mU/108 platelets and undetectable plasma FVIII) ever had spontaneous bleeding. When 2bF8tg bone marrow (BM) was transplanted into FVIII-/- rats, only 1 of 7 recipients had a bruise at the early stage of BM reconstitution, but no other spontaneous bleeding was observed during the study period. To confirm that the bleeding diathesis in FVIII-/- rats was ameliorated after platelet FVIII expression, rotational thromboelastometry and whole-blood thrombin generation assay were performed. All parameters in 2bF8tg BM transplantation recipients were significantly improved compared with FVIII-/- control rats. Of note, neither detectable levels of plasma FVIII nor anti-FVIII inhibitors were detected in 2bF8tg BM transplantation recipients. Thus, platelet-specific FVIII expression can efficiently prevent severe spontaneous bleeding in FVIII-/- rats with no anti-FVIII antibody development.
Author List
Shi Q, Mattson JG, Fahs SA, Geurts AM, Weiler H, Montgomery RRAuthors
Aron Geurts PhD Professor in the Physiology department at Medical College of WisconsinRobert R. Montgomery MD Adjunct Professor in the Pediatrics department at Medical College of Wisconsin
Qizhen Shi MD, PhD Professor in the Pediatrics department at Medical College of Wisconsin
Hartmut Weiler PhD Associate Professor in the Physiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsBlood Platelets
Factor VIII
Genetic Therapy
Hemophilia A
Humans
Phenotype
Rats
Rats, Inbred Dahl
