Effectiveness of topical gel of medical leech (Hirudo medicinalis) saliva extract on patients with knee osteoarthritis: a randomized clinical trial
Shakouri A, Adljouy N, Balkani S, Mohamadi M, Hamishehkar H, Abdolalizadeh J, Kazem Shakouri S (2017) · Complementary Therapies in Clinical Practice · n=60
Study Profile
- Design
- randomized clinical trial of a leech-saliva-extract liposomal topical gel (Tabriz University of Medical Sciences, Iran)
- Sample size (n)
- 60
- Intervention
- Topical liposome-based gel containing extracted Hirudo medicinalis saliva, applied to the symptomatic knee for 30 days
- Comparator
- Placebo gel (liposomal vehicle without leech saliva extract)
- Primary endpoint
- Pain on VAS and Lequesne index for knee OA at day 30
- Primary result
- After 30 days of leech-saliva liposomal gel, patient pain was reduced approximately 50% with concurrent reduction in joint inflammation and stiffness and improved range of motion and quality of life (p<0.001)
- Follow-up duration
- 30 days
- PMID
- 29246745
Key Findings
- First RCT to test a leech-saliva-extract pharmaceutical formulation (vs. live leeches) for knee OA
- Nano-liposomal encapsulation used to enhance transdermal absorption of leech salivary proteins
- VAS pain reduction approximately 50% over 30 days vs. placebo gel
- Improvements reported in Lequesne index, joint stiffness, and self-reported quality of life
- Provides proof-of-concept for non-invasive leech-derived therapeutics as an alternative to live-animal application
Limitations
- Single center (Tabriz University of Medical Sciences)
- Short follow-up (30 days)
- Salivary extract characterization and standardization not fully reported — batch-to-batch consistency unclear
- No comparison with live leech therapy — cannot determine relative efficacy
- Limited methodological detail on randomization and blinding in published report
Clinical Implications
Shakouri 2017 is a significant departure from the live-leech literature: instead of applying intact Hirudo medicinalis, the investigators extracted leech salivary proteins, encapsulated them in nano-liposomes, and applied them as a topical gel. This is the first RCT testing whether the active pharmacology of leech saliva can be delivered without the live-animal interface. For the ASH community, this is an important translational signal — though small and single-center, it suggests a pharmaceutical-grade leech-derived topical may eventually compete with live application for patients unwilling to undergo live-leech therapy. Clinicians should view this as exploratory until independent replication and full pharmacological characterization are available.
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