Platelet tissue factor pathway inhibitor-α dampens cardiac thrombosis and associated fibrosis in mice.
Research article published in Journal of thrombosis and haemostasis : JTH (2022)
Abstract
BACKGROUND: Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of events initiating the blood coagulation pathway. Tfpi-/- mice die during embryonic development. The absence of protease-activated receptor (PAR) 4, the major thrombin receptor on mouse platelets, rescues Tfpi-/-mice to adulthood. Among the 3 TFPI isoforms in mice, TFPIα is the only isoform within platelets (pltTFPIα) and the only isoform that inhibits prothrombinase, the enzymatic complex that converts prothrombin to thrombin. OBJECTIVES: To determine biological functions of pltTFPIα. METHODS: Tfpi-/-/Par4-/- mice were irradiated and transplanted with bone marrow from mice lacking or containing pltTFPIα. Thus, PAR4 expression was restored in the recipient mice, which differed selectively by the presence or absence of pltTFPIα and lacked other forms of TFPI. RESULTS: Recipient mice lacking pltTFPIα had reduced survival over the 200-day posttransplant period. Necropsy revealed radiation injury associated with large intraventricular platelet-rich thrombi, whereas other organs were not affected. Thrombi were associated with fibrotic presentations, including increased collagen deposition, periostin-positive activated fibroblasts, myofibroblasts, and macrophage infiltrates. Recipient mice containing pltTFPIα showed evidence of radiation injury but lacked heart pathology. CONCLUSIONS: Tfpi-/-/Par4-/- mice develop severe cardiac fibrosis following irradiation and transplantation with bone marrow lacking pltTFPIα. This pathology is markedly reduced when the mice are transplanted with bone marrow containing pltTFPIα. Thus, in this model system pltTFPIα has an important physiological role in dampening pathological responses mediated by activated platelets within the heart tissue.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of events initiating the blood coagulation pathway. Tfpimice die during embryonic development.
Why This Matters for Hirudotherapy
This animal study investigated the biological function of platelet tissue factor pathway inhibitor-alpha (pltTFPIα) using a mouse model, demonstrating that the presence of pltTFPIα dampens pathological platelet-mediated cardiac thrombosis and subsequent fibrosis. The research details how an endogenous inhibitor regulates thrombosis and tissue fibrosis in a mammalian model system following radiation injury. The study is purely preclinical and focuses exclusively on mammalian thrombosis pathways. It does not involve leeches, hirudotherapy, or the leech secretome, making its relevance to the American Society of Hirudotherapy strictly indirect and limited to basic mechanistic parallels in thrombosis regulation.
Citation
Platelet tissue factor pathway inhibitor-α dampens cardiac thrombosis and associated fibrosis in mice.
Maroney et al. · Journal of thrombosis and haemostasis : JTH, 2022
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