American Society of Hirudotherapy

Prostaglandin E1 is an efficient molecular tool for forest leech blood sucking

Behavioral pharmacology published in Frontiers in Veterinary Science (2021)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportSalivary PharmacologyZheng F et al. · Frontiers in veterinary science, 2021

Abstract

From a survival perspective, it is hypothesized that leech saliva exhibits certain physiological effects to ensure fast blood-feeding, including analgesia, anesthesia, and anti-inflammation to stay undetected by the host and vasodilatation and anti-hemostasis to ensure a steady, rapid, and sustained blood flow to the feeding site. Many anti-hemostatic compounds have been identified in leech saliva, such as hirudin, calin, and bdellin A. However, no specific substance with direct vasodilatory and anti-inflammatory function has been reported from forest leech saliva. Herein, using activity-guided analysis, prostaglandin E1 (PGE1) was identified for the first time as an efficient molecular tool for forest leech blood sucking. The structure of PGE1 was analyzed by nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectroscopy. PGE1 was found to be primarily distributed in the leech salivary gland (1228.36 ng/g body weight). We also analyzed how forest leech PGE1 affects platelet aggregation, skin vascular permeability, bleeding time, and pain. Results indicated that PGE1 efficiently inhibited platelet aggregation induced by adenosine diphosphate (ADP) (5 μM) with an IC50 of 21.81 ± 2.24 nM. At doses of 10, 100 nM, and 1 μM, PGE1 increased vascular permeability by 1.18, 5.8, and 9.2 times. It also prolonged bleeding time in a concentration-independent manner. In the formalin-induced mouse paw pain model, PGE1 suppressed acute pain. To the best of our knowledge, this is the first report on PGE1 in invertebrates. The functions of PGE1, such as vasodilation, platelet aggregation inhibition, anti-inflammation, and pain alleviation, may facilitate the ingestion of host blood by leeches.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article

Summary

Identifies prostaglandin E1 as an effective stimulant for blood-sucking by forest leeches — useful for laboratory feeding protocols and research.

Why This Matters for Hirudotherapy

This study (Zheng et al., Frontiers in Veterinary Science 2021) reports the first identification of prostaglandin E1 (PGE1) in forest-leech saliva as a molecular tool aiding blood feeding; PGE1 was concentrated in the salivary gland, inhibited ADP-induced platelet aggregation (reported IC50 of 21.81 plus or minus 2.24 nM), increased skin vascular permeability dose-dependently, prolonged bleeding time, and suppressed acute pain in a formalin mouse model, with the authors stating this is the first report of PGE1 in an invertebrate. This expands the picture of the leech secretome beyond peptides like hirudin, calin, and bdellin to include a small-molecule mediator combining vasodilation, anti-platelet, anti-inflammatory, and analgesic actions that plausibly explain why leech bites bleed and are relatively painless, reinforcing the drug-discovery rationale behind hirudotherapy. Honest caveat: these are preclinical biochemical and animal-model findings from a forest leech (not necessarily Hirudo medicinalis), characterizing a salivary component in the laboratory, not a clinical study of leech treatment in patients.

Citation

Prostaglandin E1 is an efficient molecular tool for forest leech blood sucking.

Zheng F et al. · Frontiers in veterinary science, 2021

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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.