Scorpion’s sting may hold clue for managing heart failure

It was only a pilot study, and only in mice, and it requires harvesting venom from scorpions—no easy task. But a first report on a venom-based peptide points to a new compound for treating patients with acute heart failure.

Paulus Kirchhof, MD, of the Hospital of the University of Muenster, and colleagues published results on a peptide isolated from the Judean Black scorpion online Nov. 25 in Circulation: Heart Failure.  They noted that available inotropic agents can improve hemodynamic function but with an increased risk of death, possibly from proarrhythmic effects. Finding an inotropic therapy that avoided the potentially fatal side effect would be a boon.

They focused on the selective activation of TTX-sensitive sodium channels, a pathway they speculated could improve cardiac contraction without tripping up the heart’s electrophysiologic function. A peptide isolated from the Black Judean scorpion might achieve this effect, they proposed.

Researchers harvested venom from Black scorpions in Israel over several years and shipped the venom and peptide fractions to Germany to be analyzed. They tested the venom and peptide in CD-1 wild type mice that were sedated and assessed by echocardiograph at baseline and after injection with the venom or peptide.

They monitored the cardiac contraction in the mice for 20 minutes and also took electrophysiological measurements in isolated hearts.

Mice injected with the venom survived. Their ventricular contractility increased between 20 percent and 25 percent but they also experienced ventricular arrhythmias. The peptide did not elicit ventricular arrhythmias, nor did it prolong the action potential in the isolated, beating heart.

“[O]ur findings suggest that selective activation of ‘neuronal’, TTX-sensitive sodium channels in the heart (most likely Nav1.3 channels) by a peptide isolated from the venom of Buthotus Hottentotta may be a novel therapeutic principle to increase cardiac contractility without proarrhythmic side effects,” Kirchhof et al wrote. “Further experiments are needed to validate our encouraging preliminary findings.”