Non-pungent capsaicin compounds induce mild hypothermia and improve stroke outcomes in aged mice
A preclinical study published on bioRxiv found that intraperitoneal injections of capsinoids — non-pungent relatives of capsaicin — induced mild hypothermia in aged mice after stroke, reducing brain injury and improving survival. Mild hypothermia is a known neuroprotective strategy, but its clinical use has been limited by shivering and poor temperature control in conscious patients. The findings suggest capsinoids may offer a pharmacological route to achieve therapeutic hypothermia without those drawbacks.
Researchers tested whether capsinoids, non-pungent TRPV1 receptor agonists chemically related to capsaicin, could safely induce mild hypothermia and reduce stroke damage in aged mice — a population more representative of human stroke patients. Aged male and female C57BL/6 mice (18–20 months) received intraperitoneal capsinoid injections beginning 2 or 4 hours after either permanent or temporary middle cerebral artery occlusion. The treatment produced a rapid and sustained core temperature drop of 2–4°C regardless of sex. In the permanent occlusion model, capsinoid-treated mice showed a 48% reduction in infarct volume at day 3 and a 44% decrease in chronic cortical tissue loss at day 30, along with significant improvements in gait, grip strength, and foot fault tests. In the reperfusion model, survival through day 3 was 80% in treated mice versus 33% in vehicle controls. The authors propose that targeting peripheral TRPV1 channels — rather than those in the brain injury zone — allows hypothermia induction while minimizing central side effects, potentially making this approach viable in conscious stroke patients.
What's missing
The study is a preprint and has not yet undergone peer review. All experiments were conducted exclusively in aged mice, and translation to humans remains undemonstrated; species differences in thermoregulation and TRPV1 distribution may limit generalizability. The study does not address potential cardiovascular or gastrointestinal side effects of repeated capsinoid administration in humans, or how the approach would be implemented in a clinical emergency setting. Long-term safety data beyond 30 days post-stroke are also absent.
What different sources said
- bioRxivCenter
Capsinoids (non-pungent TRPV1 agonists) promote mild hypothermia and improved outcome following stroke in aged mice
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