Mazinani N, Strilchuk AW, Baylis JR, Hur WS, Jefferies WA, Kastrup CJ. Bleeding is increased in amyloid precursor protein knockout mouse.
Res Pract Thromb Haemost 2020;
4:823-828. [PMID:
32685890 PMCID:
PMC7354397 DOI:
10.1002/rth2.12375]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/21/2020] [Accepted: 04/26/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND
Amyloid precursor protein (APP) is highly expressed in platelets. APP is the precursor to amyloid beta (Aβ) peptides that accumulate in cerebral amyloid angiopathy and plaques in Alzheimer disease. APP and its metabolites interact with many components of the coagulation system, and have both anticoagulant and procoagulant properties, but it is unclear if APP contributes to hemostasis in vivo.
OBJECTIVES
To determine whether APP contributes to hemostasis in mice, including when inhibitors of coagulation are administered.
METHODS
Blood loss in APP knockout (KO) mice was measured in liver laceration and tail transection models of hemorrhage. Blood loss was also measured following tail transection in mice given an inhibitor of coagulation factor Xa (apixaban), platelet inhibitors (aspirin + clopidogrel), tissue-type plasminogen activator (t-PA), or the antifibrinolytic tranexamic acid (TXA).
RESULTS AND DISCUSSION
Blood loss from liver lacerations was similar between APP KO mice and wild-type (WT) mice, but APP KO mice bled more from tail transections. When mice were challenged with aspirin + clopidogrel, the difference in bleeding between APP KO and WT mice was abrogated. In contrast, a difference in bleeding between the strains persisted when mice were treated with apixaban, t-PA, or TXA. Blood collected from APP KO mice and analyzed with thromboelastography had longer clotting times, and the clots were less stiff and more susceptible to fibrinolysis compared to blood from WT mice.
CONCLUSIONS
The absence of APP measurably increases bleeding in mice, which is consistent with a role for platelet-derived APP and Aβ peptides in hemostasis.
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