American Society of Hirudotherapy

Leech Tissue Factor Pathway Inhibitor

Inhibitor of tissue factor / Factor VIIa complex — blocks extrinsic coagulation pathway.

Preclinical / mechanisticLast updated: 2026-05-26 · Reviewed by ASH Editorial Board
Molecular weight of Leech Tissue Factor Pathway Inhibitor compared with other characterized leech-derived compoundsHementerin80 kDaHementin80 kDaHementin-Like Protein (HLP-1)80 kDaLeech Collagenase70 kDaHaemadipsa yanyuanensis Progr…70 kDaLeech Apyrase67 kDaCalin65 kDaHyaluronidase60 kDaAntithrombin III binding prot…58 kDaCollagenolytic Fibrinolysin55 kDaLeech Thrombospondin-Like Pro…50 kDaLeech Tissue Factor Pathway I…32 kDa
Molecular weight (kilodaltons) of Leech Tissue Factor Pathway Inhibitor (highlighted) alongside other characterized leech salivary compounds. Smaller proteins/peptides generally diffuse and act faster.

Mechanistic Evidence Box

Preclinical / mechanistic
Page type
Compound profile
Evidence type
Inhibitor of tissue factor / Factor VIIa complex — blocks extrinsic coagulation pathway.
Evidence level
Mechanistic discussion
Drug vs leech
Purified natural compound
Safety domains
Bleeding

Clinical translation limit

This leech-derived TFPI-like activity is mechanistic only and does NOT establish clinical anticoagulant efficacy. No FDA-approved derivative exists; distinct from human recombinant TFPI products in earlier development.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
32,000 Da
Source species
Hirudo medicinalis
Leech Tissue Factor Pathway Inhibitor molecular structure

Biological Targets

  • → tissue factor / Factor VIIa complex

External Resources

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    Antistasin

    Factor Xa inhibitor — prototype molecule that inspired the entire DOAC drug class (rivaroxaban, apixaban).

    Ghilanten

    Factor Xa inhibitor with anti-metastatic activity in animal cancer models — translational dual-use compound.

    Lefaxin

    Factor Xa inhibitor with anti-inflammatory properties.

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    This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.