Pigrin
Selective PAR1 antagonist from non-hematophagous Whitmania pigra — Ren 2019 demonstrates antithrombotic activity in rat without prolonging bleeding time.
Mechanistic Evidence Box
Preclinical / mechanistic- Page type
- Compound profile
- Evidence type
- Selective PAR1 antagonist from non-hematophagous Whitmania pigra — Ren 2019 demonstrates antithrombotic activity in rat without prolonging bleeding time.
- Evidence level
- Preclinical (animal)
- Drug vs leech
- Recombinant (genetically expressed)
- Safety domains
- Bleeding
Clinical translation limit
Pigrin's preclinical PAR1 antagonism + antithrombotic activity does NOT establish clinical efficacy. No FDA-approved derivative exists; W. pigra is a non-hematophagous TCM leech not on the FDA K040187 cleared species list. The 'no bleeding tendency' finding is from rodent models and cannot be extrapolated to human bleeding risk.
Molecular Profile
- Category
- Antiplatelet
- Evidence tier
- Preclinical
- Molecular weight
- 8,500 Da
- Source species
- Whitmania pigra
- Discovered
- 2019 · Ren SH et al.
Biological Targets
- → protease-activated receptor 1 (PAR1)
- → collagen-platelet interaction
Key Citations
- Ren SH et al. (2019), Chin J Nat Med · PMID 31472896
External Resources
Related Antiplatelet Compounds
Calin
Anti-platelet adhesion protein that blocks von Willebrand factor–collagen binding.
Saratin
Anti-platelet adhesion protein blocking collagen-mediated platelet activation.
Decorsin
RGD-containing peptide inhibiting platelet GP IIb/IIIa receptor — eptifibatide ancestor.
Ornatin
RGD-peptide GP IIb/IIIa antagonist — sister molecule to decorsin from a different leech species.