TY  - JOUR
A1  - Beck, Sarah
A1  - Stegner, David
A1  - Loroch, Stefan
A1  - Baig, Ayesha A.
A1  - Göb, Vanessa
A1  - Schumbutzki, Cornelia
A1  - Eilers, Eva
A1  - Sickmann, Albert
A1  - May, Frauke
A1  - Nolte, Marc W.
A1  - Panousis, Con
A1  - Nieswandt, Bernhard
T1  - Generation of a humanized FXII knock-in mouse-A powerful model system to test novel anti-thrombotic agents
JF  - Journal of Thrombosis and Haemostasis
N2  - Background
Effective inhibition of thrombosis without generating bleeding risks is a major challenge in medicine. Accumulating evidence suggests that this can be achieved by inhibition of coagulation factor XII (FXII), as either its knock-out or inhibition in animal models efficiently reduced thrombosis without affecting normal hemostasis. Based on these findings, highly specific inhibitors for human FXII(a) are under development. However, currently, in vivo studies on their efficacy and safety are impeded by the lack of an optimized animal model expressing the specific target, that is, human FXII.

Objective
The primary objective of this study is to develop and functionally characterize a humanized FXII mouse model.

Methods
A humanized FXII mouse model was generated by replacing the murine with the human F12 gene (genetic knock-in) and tested it in in vitro coagulation assays and in in vivo thrombosis models.

Results
These hF12\(^{KI}\) mice were indistinguishable from wild-type mice in all tested assays of coagulation and platelet function in vitro and in vivo, except for reduced expression levels of hFXII compared to human plasma. Targeting FXII by the anti-human FXIIa antibody 3F7 increased activated partial thromboplastin time dose-dependently and protected hF12\(^{KI}\) mice in an arterial thrombosis model without affecting bleeding times.

Conclusion
These data establish the newly generated hF12\(^{KI}\) mouse as a powerful and unique model system for in vivo studies on anti-FXII(a) biologics, supporting the development of efficient and safe human FXII(a) inhibitors.
KW  - hemostasis,
KW  - blood coagulation
KW  - factor XII
KW  - animal models
KW  - thrombosis
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259567
VL  - 19
IS  - 11
ER  - 
TY  - JOUR
A1  - Krupka, Jennifer
A1  - May, Frauke
A1  - Weimer, Thomas
A1  - Pragst, Ingo
A1  - Kleinschnitz, Christoph
A1  - Stoll, Guido
A1  - Panousis, Con
A1  - Dickneite, Gerhard
A1  - Nolte, Marc W.
T1  - The Coagulation Factor XIIa Inhibitor rHA-Infestin-4 Improves Outcome after Cerebral Ischemia/Reperfusion Injury in Rats
JF  - PLoS ONE
N2  - Background and Purpose
Ischemic stroke provokes severe brain damage and remains a predominant disease in industrialized countries. The coagulation factor XII (FXII)-driven contact activation system plays a central, but not yet fully defined pathogenic role in stroke development. Here, we investigated the efficacy of the FXIIa inhibitor rHA-Infestin-4 in a rat model of ischemic stroke using both a prophylactic and a therapeutic approach.

Methods
For prophylactic treatment, animals were treated intravenously with 100 mg/kg rHA-Infestin-4 or an equal volume of saline 15 min prior to transient middle cerebral artery occlusion (tMCAO) of 90 min. For therapeutic treatment, 100 mg/kg rHA-Infestin-4, or an equal volume of saline, was administered directly after the start of reperfusion. At 24 h after tMCAO, rats were tested for neurological deficits and blood was drawn for coagulation assays. Finally, brains were removed and analyzed for infarct area and edema formation.

Results
Within prophylactic rHA-Infestin-4 treatment, infarct areas and brain edema formation were reduced accompanied by better neurological scores and survival compared to controls. Following therapeutic treatment, neurological outcome and survival were still improved although overall effects were less pronounced compared to prophylaxis.

Conclusions
With regard to the central role of the FXII-driven contact activation system in ischemic stroke, inhibition of FXIIa may represent a new and promising treatment approach to prevent cerebral ischemia/reperfusion injury.
KW  - coagulation factor XIIa
KW  - ischemic stroke
KW  - contact activation system
KW  - FXIIa inhibitor rHA-Infestin
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167370
VL  - 11
IS  - 1
ER  -