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Saliva breaks down blood clots: vampire bats

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Vampire bat (taxidermy) / Sandstein / LicenseCC-by - Attribution

The saliva of vampire bats acts as an anticoagulant due to a protein that inhibits Factor X, an enzyme involved in the coagulation pathway.

BIOMIMICRY TAXONOMY
Summary
Vampire bats are sanguivorous or blood-eating bats. When they bite their victim, a protein in their saliva acts as an anticoagulant, which keeps their victim’s blood flowing while they feed. This anticoagulant contains the protein desmoteplase or DSPA, which was given the nickname Draculin. During the blood clotting process, DSPA inhibits Factor X, which is an enzyme involved in the coagulation pathway.

"There is a protein in the vampire bat's saliva that might one day benefit stroke sufferers, especially those who ignore their symptoms for several hours before calling 911 or going to the hospital...This enzyme--called desmoteplase, or DSPA--is what interests stroke experts. For more than eight years, researchers have studied it to see whether it can dissolve blood clots that starve the brain of oxygen during a stroke. 'When you inject (the enzyme) intravenously in a human it can also keep the blood flowing,' Torbey said."
(Hepler 2011)
Excerpt

"Activation of Factor X is a common point between the intrinsic and extrinsic pathway of blood coagulation [1]. Activated factor X (FXa) is the sole enzyme that catalyzes the conversion of prothrombin into thrombin, the key enzyme in the coagulation cascade; therefore inhibitors of this step are of considerable mechanistic and pharmacological interest. In addition to the two known physiological inhibitors of this serine protease, antithrombin III (AT-III) and the tissue factor pathway inhibitor (TFPI), several low molecular mass naturally occurring polypeptides inhibitors have been described, such as Antistasin, a 119-residue protein isolated from the mexican leech Haementeria offcinalis [2,3]; the tick anticoagulant peptide (TAP) [4], a 60-amino acid protein derived from the tick Ornithodoros moubata; Ecotin, a periplasmic protein found in Escherichia coli [5-7]; and the Ancylostoma caninum anticoagulant peptide (AcAP) [8]. These peptides behave as reversible, slow tight-binding inhibitors of FXa, where Antistasin and Ecotin are slowly cleaved by FXa, while TAP is not affected by the protease. Recently, we described a new natural FXa inhibitor, isolated from the saliva of the vampire bat Desmodus rotundus, which was named Draculin. Draculin is a 88.5 kDa glycoprotein which selectively inhibits both FXa and activated factor IX (FIXa) [9]. Furthermore, the anticoagulant activity of Draculin is highly dependent on the proper glycosylation of the polypeptide backbone [10]. The results described in this paper indicate that, in contrast to other natural FXa inhibitors, Draculin behaves as a noncompetitive, tight-binding inhibitor of FXa." (Fernandez et al. 1999:135-136)

About the inspiring organism
Med_943pxdesmodus_rotundus_feeding vampire bat
Desmodus rotundus (E. Geoffroy, 1810)
Common name: Vampire bat

Habitat(s): Artificial - Terrestrial, Caves and Subterranian Habitats, Rocky Areas
Learn more at EOL.org
Some organism data provided by: ITIS: The Integrated Taxonomic Information System
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Threat Categories LONG_LC IUCN Red List Status: Least Concern

Bioinspired products and application ideas

Application Ideas: A medicine for use in the treatment of strokes, a blood thinning medicine, a medicine for use in the treatment and prevention of heart attacks. Scientists hope to replace tissue-type plasminogen activator (tPA) with DSPA to treat stroke victims. DSPA has shown promise when used to treat ischemic strokes, which occur in about 87 percent of stroke victims. It is hoped that DSPA will be effective for up to nine hours after symptoms first appear versus three hours with tPA.

Industrial Sector(s) interested in this strategy: Pharmacology, Parenteral sciences

References
Fernandez AZ; Tabalante A; Beguin S; Hemker C; Apitz-Castro R. 1999. Draculin, the anticoagulant factor in vampire bat saliva, is a tight-binding, noncompetitive inhibitor of activated factor X. Biochimica et Biophysica Acta: Protein Structure and Molecular Enzymology. 1434(2): 135-142.
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Hepler L. 2011. Researchers say bat could aid stroke victims. The Columbus Dispatch [Internet], Accessed May 29.
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Sherry
about 1 year ago
Thanks to Amanda Rupert for contributing this strategy.
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