May salivary gland secretory proteins from hematophagous leeches reach pharmacologically relevant concentrations in the vertebrate host?

Pharmacology study published in PLoS ONE (2013)

Última actualización: June 18, 2026Revisado por: ASH Editorial Board

Research article — evidence reviewArticle reference

Evidence: Research reportFarmacología salivalEnsayos clínicosLemke S et al. · PloS one, 2013

Abstract

Saliva of hematophagous leeches (Hirudo sp.) contains bioactive proteins which allow the leech proper feeding and storage of ingested blood, but may also exert effects in the host. Leech therapy is used to treat many different ailments in humans, although only a small fraction of salivary proteins are characterized yet. Moreover, we do not know whether complete transfer of salivary proteins stored in the unicellular salivary glands in a leech to the host during feeding may generate concentrations that are sufficiently high to affect physiological processes in the host. Our 3D reconstruction of a portion of internal leech tissue from histological sections revealed that one leech contains approx. 37,000 salivary gland cells. Using tissue slices from pig liver and mouse skeletal muscle for reference, we obtained data for protein densities in leech salivary gland cells. As individual salivary cells are voluminous (67,000 µm(3)) and the stored proteins are densely packed (approx. 500 µg/mm(3)), we extrapolated that a single leech may contain up to 1.2 mg of salivary proteins. Analyzing protein extracts of unfed or fed leeches by 2D electrophoresis, we calculated the relative molar amounts of individual salivary proteins in the mass range of 17-60 kDa which may be released from a single leech during feeding. Distribution of these salivary proteins in the host (assumed plasma volume of 5 l) may result in concentrations of individual compounds between 3 and 236 pmol/l. Such concentrations seem sufficiently high to exert biochemical interactions with target molecules in the host.

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

Publication typeJournal Article

Indexed MeSH termsAnimalsDensitometryElectrophoresis, Gel, Two-DimensionalHumansLeechesLiverMiceMicrotomyModels, AnatomicMuscle, SkeletalReference StandardsSalivary Glands

Resumen

Quantitative analysis of leech salivary protein release during feeding to determine whether host-tissue concentrations reach pharmacologically active levels.

Por qué esto importa para la hirudoterapia

This study used 3D reconstruction of leech internal tissue from histological sections, protein density measurements from pig liver and mouse skeletal muscle reference tissues, and 2D electrophoresis of fed and unfed leeches to estimate that a single Hirudo leech may contain up to 1.2 mg of salivary proteins, potentially yielding host plasma concentrations of individual compounds between 3 and 236 pmol/L. For hirudotherapy, this is relevant because it provides a quantitative estimate of whether bioactive salivary proteins transferred during leech feeding could reach levels sufficient to affect physiological processes in the host; the authors suggest these concentrations seem sufficiently high to exert biochemical interactions with target molecules. However, these are extrapolations based on an assumed plasma volume (5 L) and estimated total gland content—not measured in vivo concentrations from actual feeding events—and the study does not confirm biological activity at these levels.