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Open Access Highly Accessed Research article

Drug-induced mild therapeutic hypothermia obtained by administration of a transient receptor potential vanilloid type 1 agonist

Keld Fosgerau1*, Uno J Weber1, Jacob W Gotfredsen1, Magdalena Jayatissa1, Carsten Buus2, Niels B Kristensen3, Mogens Vestergaard3, Peter Teschendorf4, Andreas Schneider4, Philip Hansen5, Jakob Raunsø1, Lars Køber1, Christian Torp-Pedersen1 and Charlotte Videbaek1

Author Affiliations

1 Neurokey AS, Diplomvej 372, DK-2800 Lyngby, Denmark

2 Pipeline Biotech A/S, Røvedvej 1, Spørring, DK-8380 Trige, Denmark

3 Department of Animal Health and Bioscience, Faculty of Agricultural Sciences, Aarhus University, Box 50, DK-8830 Tjele, Denmark

4 Department of Anesthesiology and Intensive Care Medicine, University Hospital of Cologne, Kerpener Strasse 62, D-50937 Cologne, Germany

5 CMC Consult Aps, Agern Allé 3, DK-2970 Hørsholm, Denmark

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BMC Cardiovascular Disorders 2010, 10:51  doi:10.1186/1471-2261-10-51

Published: 9 October 2010

Abstract

Background

The use of mechanical/physical devices for applying mild therapeutic hypothermia is the only proven neuroprotective treatment for survivors of out of hospital cardiac arrest. However, this type of therapy is cumbersome and associated with several side-effects. We investigated the feasibility of using a transient receptor potential vanilloid type 1 (TRPV1) agonist for obtaining drug-induced sustainable mild hypothermia.

Methods

First, we screened a heterogeneous group of TRPV1 agonists and secondly we tested the hypothermic properties of a selected candidate by dose-response studies. Finally we tested the hypothermic properties in a large animal. The screening was in conscious rats, the dose-response experiments in conscious rats and in cynomologus monkeys, and the finally we tested the hypothermic properties in conscious young cattle (calves with a body weight as an adult human). The investigated TRPV1 agonists were administered by continuous intravenous infusion.

Results

Screening: Dihydrocapsaicin (DHC), a component of chili pepper, displayed a desirable hypothermic profile with regards to the duration, depth and control in conscious rats. Dose-response experiments: In both rats and cynomologus monkeys DHC caused a dose-dependent and immediate decrease in body temperature. Thus in rats, infusion of DHC at doses of 0.125, 0.25, 0.50, and 0.75 mg/kg/h caused a maximal ΔT (°C) as compared to vehicle control of -0.9, -1.5, -2.0, and -4.2 within approximately 1 hour until the 6 hour infusion was stopped. Finally, in calves the intravenous infusion of DHC was able to maintain mild hypothermia with ΔT > -3°C for more than 12 hours.

Conclusions

Our data support the hypothesis that infusion of dihydrocapsaicin is a candidate for testing as a primary or adjunct method of inducing and maintaining therapeutic hypothermia.