Prevention and Treatment of Nonfreezing Cold Injuries and Warm Water Immersion Tissue Injuries: A Supplement to the Wilderness Medical Society Clinical Practice Guidelines

Dermorphin [D-Arg2, Lys4] (1-4) Amide Alleviates Frostbite-Induced Pain by Regulating TRP Channel-Mediated Microglial Activation and Neuroinflammation

Cold injury or frostbite is a common medical condition that causes serious clinical complications including sensory abnormalities and chronic pain ultimately affecting overall well-being. Opioids are the first-choice drug for the treatment of frostbite-induced chronic pain; however, their notable side effects, including sedation, motor incoordination, respiratory depression, and drug addiction, present substantial obstacle to their clinical utility. To address this challenge, we have exploited peripheral mu-opioid receptors as potential target for the treatment of frostbite-induced chronic pain. In this study, we investigated the effect of dermorphin [D-Arg2, Lys4] (1-4) amide (DALDA), a peripheral mu-opioid receptor agonist, on frostbite injury and hypersensitivity induced by deep freeze magnet exposure in rats. Animals with frostbite injury displayed significant hypersensitivity to mechanical, thermal, and cold stimuli which was significant ameliorated on treatment with different doses of DALDA (1, 3, and 10 mg/kg) and ibuprofen (100 mg/kg). Further, molecular biology investigations unveiled heightened oxido-nitrosative stress, coupled with a notable upregulation in the expression of TRP channels (TRPA1, TRPV1, and TRPM8), glial cell activation, and neuroinflammation (TNF-α, IL-1β) in the sciatic nerve, dorsal root ganglion (DRG), and spinal cord of frostbite-injured rats. Treatment with DALDA leads to substantial reduction in TRP channels, microglial activation, and suppression of the inflammatory cascade in the ipsilateral L4-L5 DRG and spinal cord of rats. Overall, findings from the present study suggest that activation of peripheral mu-opioid receptors mitigates chronic pain in rats by modulating the expression of TRP channels and suppressing glial cell activation and neuroinflammation.

Frostbite and Mortality in Mountaineering Women: A Scoping Review-UIAA Medical Commission Recommendations

Kriemler, Susi, Kastė Mateikaitė-Pipirienė, Alison Rosier, Linda E. Keyes, Peter Paal, Marija Andjelkovic, Beth A. Beidleman, Mia Derstine, Jacqueline Pichler Hefti, David Hillebrandt, Lenka Horakova, and Dominique Jean; for the UIAA MedCom Writing Group on Women's Health in the Mountains. Frostbite and mortality in mountaineering women: a scoping review-UIAA Medical Commission recommendations. High Alt Med Biol. 24:247-258, 2023. Background: The harsh environment of high altitudes (HA) poses many serious health risks for mountaineers, including cold injuries and death. The aim of this work was to review whether female mountaineers are at special risk for frostbite or death at HA compared with their male counterparts. Methods: The UIAA Medical Commission convened an international author team to review women's health issues at HA and to publish updated recommendations. Pertinent literature from PubMed and Cochrane was identified with additional publications found by hand search. The primary search focus was for articles assessing cold injuries and death in women mountaineers at HA. Results: We reviewed the literature and identified 20 relevant studies: 2 studies on frostbite at HA, plus 7 studies and 1 report for death at HA. An additional 10 studies about frostbite at low altitude were included. We found that female mountaineers at HA were at lower risk of death than their male counterparts, but sex differences in frostbite were inconclusive. Conclusions: The frequency of cold injuries and mortality in female mountaineers is not yet well studied, and the studies that have been published tend to lack precise exposure data. More studies and registries with sex-differentiated data are needed.