Non-pungent capsaicin compounds induce mild hypothermia and improve stroke outcomes in aged mice
Researchers found that capsinoids—non-spicy compounds related to capsaicin—can induce mild hypothermia in aged mice after stroke, reducing brain injury by 48% and improving survival rates. Mild hypothermia is known to protect brain tissue after stroke, but triggering it in awake patients is difficult due to shivering; capsinoids activate heat-sensing receptors in the abdomen rather than the brain, potentially avoiding this problem. The findings suggest capsinoids could offer a practical way to deliver neuroprotective hypothermia to conscious stroke patients.
In a preclinical study published on bioRxiv, researchers tested whether capsinoids—non-pungent agonists of the TRPV1 heat-sensing receptor—could safely induce mild hypothermia in aged mice following stroke. Aged mice (18-20 months old) underwent either permanent or temporary middle cerebral artery occlusion, then received intraperitoneal injections of capsinoids or vehicle control starting 2-4 hours after stroke. Capsinoids rapidly lowered core body temperature by 2-4°C and sustained this reduction for 4.5-6 hours. In the permanent occlusion model, capsinoid treatment reduced infarct volume by 48% at day 3 and chronic tissue loss by 44% at day 30, with significant improvements in motor function tests. In the temporary occlusion model, survival was 80% in capsinoid-treated mice versus 33% in controls through day 3. The authors conclude that peripheral TRPV1 activation via capsinoids offers a promising approach to induce neuroprotective hypothermia in conscious stroke patients without the shivering and temperature control problems associated with current cooling methods.
Limitations & open questions
The study was conducted only in mice; translation to human efficacy and safety remains to be demonstrated. The optimal timing, dosing, and duration of capsinoid administration in humans are unknown. Long-term safety and potential off-target effects of repeated capsinoid exposure have not been characterized. The mechanism by which peripheral TRPV1 activation triggers hypothermia is not fully explained in the abstract.
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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