American Society of Hirudotherapy

Eglin c, a pharmacologically active elastase inhibitor

Pharmacology article published in European Journal of Respiratory Diseases Supplement (1985)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportDrug DevelopmentSalivary PharmacologySchnebli HP, Seemüller U, Fritz H et al. · European journal of respiratory diseases. Supplement, 1985

Abstract

Eglin c is an elastase/cathepsin G inhibitor from leech Hirudo medicinalis. The gene for this 70 aminoacid peptide was synthesized chemically, cloned and expressed by E. coli. Here we report biochemical and pharmacological studies. The rate of complex formation between Eglin c and human leukocyte elastase (HLE) or human cathepsin G (H. Cat. G) was determined and compared to those of a number of other proteinase/proteinase-inhibitor interactions (alpha 1 PI and alpha 2M). The association rate constants of Eglin c with the leukocyte enzymes are of the same order of magnitude as those with the naturally occurring inhibitors alpha 1 PI and alpha 2M. The association rate constant of Eglin c (extracted from leech) and Eglin c (biotechnology product) with HLE was found to be identical. The equilibrium constants Ki of the Eglin c/HLE and the Eglin c/H. Cat. G interactions are in the order of 10(-10) M. In an experiment with the hamster emphysema model, 0.5 mg or 2 mg of Eglin c applied intratracheally one hour before an HLE-insult completely protected the animals against emphysema and no signs of toxicity due to Eglin c were observed.

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

Publication typeJournal Article
Indexed MeSH termsAnimalsCricetinaeDNA, RecombinantHumansKineticsProtease InhibitorsProteinsPulmonary EmphysemaSerpins

Summary

Biochemical and pharmacological characterization of recombinant leech eglin c versus natural eglin c, showing identical association rate constants with human leukocyte elastase and complete protection against HLE-induced emphysema in hamsters.

Why This Matters for Hirudotherapy

This study characterizes eglin c, an elastase/cathepsin G inhibitor from Hirudo medicinalis, including its chemical gene synthesis, cloning, and expression in E. coli. The abstract reports that association rate constants with human leukocyte elastase and cathepsin G are comparable to natural inhibitors (α1-PI, α2M), equilibrium constants (Ki) are on the order of 10⁻¹⁰ M, and recombinant eglin c was identical in activity to leech-extracted eglin c. In a hamster emphysema model, intratracheal eglin c completely protected against HLE-induced emphysema with no toxicity. This is relevant to ASH's domain as it characterizes a pharmacologically active component of the leech secretome beyond hirudin, demonstrating the breadth of bioactive molecules in leech saliva. However, the study is preclinical (animal model) and involves a recombinant protein rather than whole-organism leech therapy.

Citation

Eglin c, a pharmacologically active elastase inhibitor.

Schnebli HP, Seemüller U, Fritz H et al. · European journal of respiratory diseases. Supplement, 1985

DOIPubMed

Added to ASH library: May 26, 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.