American Society of Hirudotherapy

Cysteine-Rich Anticoagulant (CRA)

Novel cysteine-rich recombinant anticoagulant from Hirudo medicinalis saliva — strong anticoagulant activity in clotting assays; C-terminal motif governs membrane affinity.

Preclinical / mechanisticLast updated: 2026-05-27 · Reviewed by ASH Editorial Board
Molecular weight of Cysteine-Rich Anticoagulant (CRA) 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 kDaCysteine-Rich Anticoagulant (…12 kDa
Molecular weight (kilodaltons) of Cysteine-Rich Anticoagulant (CRA) (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
Novel cysteine-rich recombinant anticoagulant from Hirudo medicinalis saliva — strong anticoagulant activity in clotting assays; C-terminal motif governs membrane affinity.
Evidence level
In vitro
Drug vs leech
Recombinant (genetically expressed)
Safety domains
Bleeding

Clinical translation limit

CRA's in vitro anticoagulant activity (3.7-5.5 mg/L recombinant yield, retained clotting-assay activity) does NOT establish clinical efficacy of any whole-leech or recombinant therapy. No FDA-approved CRA derivative exists; characterization remains at scale-up / purification stage.

Molecular Profile

Category
Anticoagulant
Evidence tier
Preclinical
Molecular weight
12,000 Da
Source species
Hirudo medicinalis
Discovered
2025 · Manuvera VA et al.
Cysteine-Rich Anticoagulant (CRA) molecular structure

Biological Targets

  • coagulation cascade (TT / PT / aPTT prolongation; membrane-associated mechanism)

Key Citations

  1. Manuvera VA et al. (2025), Biomolecules · PMID 41463289

External Resources

    Related Anticoagulant Compounds

    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.