Leech therapy: when once is not enough
Research article published in Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis (1991)
Abstract
Venous congestion is a constant threat in the survival of free flaps, pedicled flaps, tissue replantations and traumatized tissue. Leech therapy has proved effective in salvaging much of these compromised tissues. To be effective, leeches must be both readily available and hungry, requirements not always easily met. Our investigation seeks to establish a means to return sated leeches to their previous unfed, hungry state for reuse. Sated leeches were purged of their blood meals by placement in 3% hypertonic saline or by gentle finger pressure, then exposed to serotonin 0 microM (control), 10 microM, 30 microM or 90 microM for 20 min. Subsequent rebiting/refeeding was observed and analysed. Leeches bathed in serotonin rebit or reattached at nearly four times the rate of unexposed leeches; 30% vs 8% respectively. Biting, however, is not refeeding. Overall, 41 leeches were treated with serotonin with four (10%) refeeding. Those that refed consumed a significantly smaller blood meal than the initial feeding; 50% +/- 47% SD vs 348% +/- 143% SD of original body weight. None of the control group refed. As a method for routinely reusing leeches, serotonin bathing cannot be recommended. In the immediate postoperative period with the sudden emergence of venous congestion requiring leech therapy, but with an inadequate number available, this 20% [corrected] refeed rate after 10 microM serotonin exposure could potentially determine the success or failure of the flap/replantation until fresh leeches are made available.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
An experimental study found serotonin bathing of sated leeches increased rebiting about fourfold but only achieved 10% refeeding with smaller blood meals, offering limited potential for leech reuse when fresh supplies are lacking.
Why This Matters for Hirudotherapy
This study directly examined a practical challenge in hirudotherapy: whether sated leeches could be purged of their blood meals and induced to refeed, thereby enabling reuse when demand exceeds supply. Using hypertonic saline or manual pressure to purge leeches, followed by serotonin exposure at graded concentrations, the authors observed that serotonin-bathed leeches rebit at roughly four times the rate of unexposed controls (30% vs. 8%), though actual refeeding occurred in only 10% of treated leeches, with significantly smaller blood meals than initial feedings. The study addresses logistical aspects of leech reuse in the context of venous congestion in flaps and replantations. A key caveat is that, by the authors' own conclusion, serotonin bathing cannot be recommended for routine leech reuse; the modest refeed rate may only serve as a temporary stopgap in emergencies when fresh leeches are unavailable, and the study involved a limited sample of 41 treated leeches.
Citation
Reference (Vancouver style)
West BR, Nichter LS, Halpern D. Leech therapy: when once is not enough. Blood Coagul Fibrinolysis. 1991;2(1):197-200. PMID: 1772992
Bibliographic details (authors, volume, pages, DOI) are taken from the PubMed record.
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