Novel Leech Antimicrobial Peptides, Hirunipins: Real-Time 3D Monitoring of Antimicrobial and Antibiofilm Mechanisms Using Optical Diffraction Tomography
Research article published in Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2025)
Abstract
Antimicrobial peptides (AMPs) are promising agents for treating antibiotic-resistant bacterial infections. Although discovering novel AMPs is crucial for combating multidrug-resistant bacteria and biofilm-related infections, their clinical potential relies on precise, real-time evaluation of efficacy, toxicity, and mechanisms. Optical diffraction tomography (ODT), a label-free imaging technology, enables real-time visualization of bacterial morphological changes, membrane damage, and biofilm formation over time. Here, a computational analysis of the leech transcriptome using an advanced AI-based peptide screening strategy with ODT to identify potential AMPs is employed. Among the 19 potential AMPs identified, hirunipin 2 demonstrates potent antibacterial activity, low mammalian cytotoxicity, and minimal hemolytic effects. It demonstrates efficacy comparable to melittin, resistance to physiological salts and human serum, and a low likelihood of inducing bacterial resistance. Microscopy and 3D-ODT confirm its disruption of bacterial membranes and intracellular aggregation, leading to cell death. Notably, hirunipin 2 effectively inhibits biofilm formation, eradicates preformed biofilms, and synergizes with antibiotics against multidrug-resistant Acinetobacter baumannii (MDRAB) by enhancing membrane permeability. Additionally, hirunipin 2 significantly suppresses pro-inflammatory cytokine expression in LPS-stimulated macrophages, highlighting its anti-inflammatory properties. These findings highlight hirunipin 2 as a strong candidate for developing novel antibacterial, anti-inflammatory, and antibiofilm therapies, particularly against multidrug-resistant bacterial infections.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Antimicrobial peptides (AMPs) are promising agents for treating antibiotic-resistant bacterial infections.
Why This Matters for Hirudotherapy
Using AI-based screening of the leech transcriptome combined with label-free optical diffraction tomography, this study identified 19 candidate antimicrobial peptides and characterized hirunipin 2, which showed potent antibacterial activity comparable to melittin, low mammalian cytotoxicity and hemolysis, disruption of bacterial membranes, inhibition and eradication of biofilms, synergy with antibiotics against multidrug-resistant Acinetobacter baumannii, and suppression of pro-inflammatory cytokines in stimulated macrophages. This directly advances the medicinal-leech secretome drug-discovery story by extending leech-derived bioactives beyond anticoagulation into a new class of antimicrobial and anti-biofilm agents, mechanistically plausible support for the long-observed low infection rates around leech feeding. The important caveat is that these are preclinical, in vitro and cell-based findings (bacterial cultures, biofilm models, and macrophage and other cell lines); hirunipin 2 is a discovery-stage candidate with no animal efficacy or human data reported here, so it does not establish clinical benefit and must not be presented as an approved or proven therapy.
Citation
Novel Leech Antimicrobial Peptides, Hirunipins: Real-Time 3D Monitoring of Antimicrobial and Antibiofilm Mechanisms Using Optical Diffraction Tomography
Kumar SD et al. · Advanced science (Weinheim, Baden-Wurttemberg, Germany), 2025
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