Leech therapy: when once is not enough
Experimental study published in Blood Coagul Fibrinolysis (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
Serotonin bathing of sated leeches induced rebiting in 30% versus 8% control but only 10% refeeding with smaller blood meals (50% vs 348% body weight), insufficient for routine leech reuse.
Why This Matters for Hirudotherapy
This study investigated whether sated leeches could be returned to a hungry state for reuse by purging blood meals via hypertonic saline or manual pressure, followed by serotonin exposure at varying concentrations. The findings showed that leeches bathed in serotonin rebit or reattached at nearly four times the rate of controls (30% vs 8%), but true refeeding was much lower—only 10% of serotonin-treated leeches refed, consuming significantly smaller meals than initial feedings. The authors conclude that serotonin bathing cannot be recommended for routine leech reuse, though a corrected 20% refeed rate at 10 microM serotonin could serve as a stopgap when insufficient leeches are available. This research addresses a practical supply limitation in hirudotherapy, though the low refeed rate limits clinical utility and no actual patient outcomes are reported.
Citation
Leech therapy: when once is not enough.
West BR et al. · Blood coagulation & fibrinolysis, 1991
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