High altitude medicine & biology最新文献

{"title":"Hypoxic Training Systems for Climbing at Extremely High Altitude: A Survey of Current Practice.","authors":"Cormac Zachar, Colin K Grissom, Scott E McIntosh, Andrew M Luks","doi":"10.1177/15578682251384844","DOIUrl":"https://doi.org/10.1177/15578682251384844","url":null,"abstract":"<p><p>Zachar, Cormac, Colin K. Grissom, Scott E. McIntosh, and Andrew M. Luks. Hypoxic training systems for climbing at extremely high altitude: A survey of current practice. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background:</i></b> Anecdotal report suggests increasing numbers of climbers are using hypoxic training systems to prepare for expeditions to extremely high elevations but there is little systematic information regarding their incorporation into training approaches. <b><i>Methods:</i></b> An anonymous survey of mountaineers who have attempted to climb mountains >6,000 m in the past 20 years. <b><i>Results:</i></b> Responses from 385 individuals were included in the analysis; the majority reside in North America. In total, 24.6% of respondents have used a hypoxic training system during sleep or exercise training. Climbers who use these systems cite multiple reasons for their use, including reducing the risk of acute altitude illness, improving exercise capacity at high altitude, and increasing the odds of summit success. Climbers obtain information on employing these systems from multiple and varied sources. Perceptions about the utility of hypoxic training systems are more positive among people who use the systems for sleep or exercise training compared with those who do not. <b><i>Conclusions:</i></b> Nearly 25% of climbers in our survey used hypoxic training systems to prepare for mountains >6,000 m and hold generally positive views of the utility of these systems. Further research is warranted to assess their effectiveness and refine protocols for incorporation into training programs.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145185635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innate Immune Phenotypes During Acute High-Altitude Exposure.","authors":"Abel Vargas, Veronica Penuelas, Karapet G Mkrtchyan, Kathy Pham, Shyleen Frost, Esteban A Moya, James J Yu, Tatum S Simonson, Erica C Heinrich","doi":"10.1177/15578682251379737","DOIUrl":"https://doi.org/10.1177/15578682251379737","url":null,"abstract":"<p><p>Vargas, Abel, Veronica Penuelas, Karapet G Mkrtchyan, Kathy Pham, Shyleen Frost, Esteban A Moya, James J Yu, Tatum S Simonson, and Erica C Heinrich. Innate immune phenotypes during acute high-altitude exposure. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Introduction:</i></b> High altitude is a physiologically stressful environment due to limited oxygen availability. Decades of study reveal the complex plasticity in many physiological systems that manifests at high altitude to maintain oxygen delivery. However, there are gaps in our knowledge regarding how high-altitude exposure influences immune function. Since tissue and cellular hypoxia occur during injury and infection, we hypothesized that sustained hypoxemia during high-altitude travel may impact inflammatory and immune phenotypes due to crosstalk between hypoxia and inflammatory response pathways. <b><i>Methods:</i></b> We recruited 17 healthy participants and examined their immune phenotypes at sea level and during 3 days at 3,800 m elevation. Specific attention was paid to neutrophil phenotypes because changes in these cells have not been reported at high altitude. <b><i>Results:</i></b> We found several impacts of high altitude on immune cell populations, including shifts in monocytes from classical to intermediate (<i>p</i> = 0.004 after 1 night at high altitude [HA1], and <i>p</i> < 0.001 after 2 nights at high altitude [HA2]) and nonclassical subsets (<i>p</i> = 0.013 on HA2), and increases in total B cells (<i>p</i> = 0.001 on HA2, <i>p</i> = 0.004 [HA3]). An effect of altitude was found for neutrophil CD15 expression (<i>p</i> < 0.001), with a trend toward increased expression over time at high altitude. Higher Acute Mountain Sickness (AMS) scores on the second day at high altitude were associated with more pronounced shifts to nonclassical monocyte populations (<i>R</i>² = 0.79, <i>p</i> = 0.001). These data indicate that acute high-altitude travel results in a pro-inflammatory immune response, which may contribute to AMS. This response appears to blunt with acclimatization, although elevation in B cells remain by HA3.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145174235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk Determinants of Acute Mountain Sickness in Trekkers in the Nepali Himalaya: A 36-Year Follow-Up.","authors":"Hannah Cameron, Marion McDevitt, Bengt Kayser, Craig Kutz, Suvash Dawadi, Alana Hawley","doi":"10.1177/15578682251382432","DOIUrl":"https://doi.org/10.1177/15578682251382432","url":null,"abstract":"<p><p><b><i>Introduction:</i></b> Non-acclimatized trekkers risk developing acute mountain sickness (AMS) at high altitudes. We surveyed trekkers on the Annapurna Circuit in Nepal (peak 5,416 m) to assess AMS incidence and risk factors. Results were compared to 1986, 1998, and 2010 surveys. <b><i>Methods:</i></b> Paper and electronic surveys were distributed to English-speaking trekkers who stopped at the Manang Aid Post (3,500 m). AMS was assessed with the Lake Louise Score (LLS; cutoffs ≥3 and ≥5) and the Environmental Symptom Questionnaire AMS-C score (cutoff ≥0.7). <b><i>Results:</i></b> One hundred and forty-three surveys were returned. Incidence of AMS was 45%, 29%, and 19% (LLS ≥3, LLS ≥5, and AMS-C). AMS incidence was similar to that in 2010 and lower than in 1986 and 1998. In this study, body mass index (BMI) was a significant risk factor for AMS. Seventy-five percent of trekkers had elementary awareness of AMS, compared to 42% in 2010. Trekkers had slower ascent rates and 49% used prophylactic acetazolamide, compared to 44% (2010), 12% (1998), and 1% (1986). <b><i>Conclusions:</i></b> BMI was a predictor of AMS. Awareness of AMS was greater when compared to past studies; however, AMS rates stayed relatively stable between 2010 and the present. Whether awareness reduces the incidence of other potentially lethal altitude illnesses requires further investigation.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Causal Relationships Between High-Altitude Adaptation, Metabolic Traits, and Tumors: Insights from Mendelian Randomization.","authors":"Xingkai Zhang, Liang He, Kai Li, Wen Li, Li Wang, Ling Chen, Qinghai Shi","doi":"10.1177/15578682251382795","DOIUrl":"https://doi.org/10.1177/15578682251382795","url":null,"abstract":"<p><p>Zhang, Xingkai, Liang He, Kai Li, Wen Li, Li Wang, Ling Chen, and Qinghai Shi. Causal relationships between high-altitude adaptation, metabolic traits, and tumors: Insights from Mendelian randomization. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background and Objectives:</i></b> Previous studies suggest that high-altitude adaptation (HAA) and metabolic traits in high-altitude populations correlate with tumor risk, but causal mechanisms remain unclear. This Mendelian randomization (MR) study investigated genetic links between HAA, metabolic traits, and tumor susceptibility while exploring potential mediation effects. <b><i>Methods:</i></b> Genome-wide association studies data for HAA, metabolic traits, and tumors were sourced from public databases. Inverse variance weighting served as the primary analytical method, supplemented by weighted mode, MR-Egger, and weighted median. Sensitivity analyses and two-step MR (TSMR) assessed robustness and mediation pathways. <b><i>Results:</i></b> We identified a potential association between HAA and a decreased risk of pancreatic cancer (odds ratio [OR] = 8.94e-8, <i>p</i> = 0.011) and cervical cancer (OR = 8.04e-6, <i>p</i> = 0.005). In contrast, HAA showed a potential link to an increased risk of esophageal cancer (OR = 3230.25, <i>p</i> = 0.03) and hepatocellular carcinoma (OR = 2080.07, <i>p</i> = 0.015). Several metabolic traits, particularly platelet-related indices, were identified as potentially associated with tumorigenesis. However, although possible mediating pathways were suggested, no metabolic trait demonstrated a statistically significant mediating effect. <b><i>Conclusion:</i></b> These findings highlight HAA's complex role in tumor susceptibility and provide a genetic framework for understanding tumor disparities in high-altitude regions.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraoperative Opioid-Free Anesthesia with Dexmedetomidine and Esketamine Versus Conventional General Anesthesia in Laparoscopic Cholecystectomy at 3,600 m: A Randomized Trial on Hemodynamic Stability and Postoperative Recovery.","authors":"Ke Tu, Lei Tian, Qi Zhu, Kailian Bai, Lin Li, Mengmei Fu, Mengxia Wang, Lei Zhang, Zhuo Zhan, Haoxi Li, Xiaojun Li, Ruofan Yi, Cheng Jiang, Hua Huang, Mingming Zhang","doi":"10.1177/15578682251381135","DOIUrl":"https://doi.org/10.1177/15578682251381135","url":null,"abstract":"<p><p>Tu, Ke, Lei Tian, Qi Zhu, Kailian Bai, Lin Li, Mengmei Fu, Mengxia Wang, Lei Zhang, Zhuo Zhan, Haoxi Li, Xiaojun Li, Ruofan Yi, Cheng Jiang, Hua Huang, and Mingming Zhang. Intraoperative opioid-free anesthesia with dexmedetomidine and esketamine versus conventional general anesthesia in laparoscopic cholecystectomy at 3,600 m: A randomized trial on hemodynamic stability and postoperative recovery. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background:</i></b> Opioid-free anesthesia (OFA) is gaining attention as an alternative to opioid-based techniques. However, its hemodynamic and clinical characteristics at high altitudes, where hypoxia and resource limitations prevail, remain unclear. <b><i>Methods:</i></b> In this single-blind randomized trial, 48 patients undergoing laparoscopic cholecystectomy at 3,600 m were assigned to either a conventional general anesthesia (CGA) group (sevoflurane, sufentanil, remifentanil) or an OFA group (sevoflurane, dexmedetomidine, esketamine). The primary outcome was intraoperative mean arterial pressure (MAP); secondary outcomes included heart rate (HR), awakening time, sedation level, patient satisfaction, postoperative pain, postoperative nausea and vomiting (PONV), perioperative medication use, and adverse events. <b><i>Results:</i></b> Compared with CGA, the OFA group maintained higher intraoperative MAP, with significant differences after induction (OFA: 87.9 ± 12.3 vs. CGA: 77.2 ± 11.7 mmHg, <i>p</i> < 0.005) and 10 minutes after incision (OFA: 83.5 ± 14.9 vs. CGA: 72.5 ± 9.8 mmHg, <i>p</i> < 0.005). The CGA group exhibited a significant MAP decline at 10 minutes postincision (72.5 ± 9.8 vs. baseline: 83.0 ± 9.1 mmHg, <i>p</i> < 0.001), whereas the OFA group showed a transient MAP increase after intubation (96.1 ± 16.1 vs. baseline: 85.8 ± 7.8 mmHg, <i>p</i> < 0.01). HR trends paralleled MAP changes. Awakening time was significantly longer with OFA (OFA: 20.4 ± 7.5 min vs. CGA: 10.6 ± 8.2 min, <i>p</i> < 0.001), while pain scores at 6 and 12 hours were lower (<i>p</i> < 0.005). Sedation, satisfaction, PONV, and medication use were comparable. No severe adverse events occurred. <b><i>Conclusions:</i></b> At high altitudes, OFA with dexmedetomidine and esketamine exhibited distinct clinical characteristics compared with opioid-based anesthesia, maintaining blood pressure and postoperative analgesia but less effectively blunting intubation-induced pressor responses and prolonging awakening time. These factors should be weighed when selecting anesthesia strategies in resource-limited, high-altitude settings, particularly when managing large numbers of patients.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145086003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy and Safety of Extended-Release Acetazolamide Capsules for the Prevention of Acute Mountain Sickness: A Randomized, Double-Blind, Placebo-Controlled Phase III Trial.","authors":"Zhuoga Danzeng, Rui Zhang, Luobu Gesang, Jin Wang, Bai Ci, Zejuan Wang, Zhuoma Ciren, Quzhen Gesang, Yangzong Suona, Xiaona Liu, Quzong Zhaxi, Cuomu Baima, Binyun Liu, Zhuoga Baima, Wei Cong, Qiangba Dingzeng","doi":"10.1177/15578682251375409","DOIUrl":"https://doi.org/10.1177/15578682251375409","url":null,"abstract":"<p><p>Danzeng, Zhuoga, Rui Zhang, Luobu Gesang, Jin Wang, Bai Ci, Zejuan Wang, Zhuoma Ciren, Quzhen Gesang, Yangzong Suona, Xiaona Liu, Quzong Zhaxi, Cuomu Baima, Binyun Liu, Zhuoga Baima, Wei Cong, and Qiangba Dingzeng. Efficacy and safety of extended-release acetazolamide capsules for the prevention of acute mountain sickness: a randomized, double-blind, placebo-controlled phase III trial. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background:</i></b> Acute mountain sickness (AMS) frequently affects individuals ascending rapidly to high altitudes. Data on acetazolamide prophylaxis in Asian populations remain limited. To evaluate the efficacy and safety of acetazolamide for the prevention of AMS in the Han Chinese population. <b><i>Methods:</i></b> In this multicenter, randomized, double-blind, placebo-controlled phase III trial, 288 healthy Chinese Han adults traveled from Peking (43.5 m) to Lhasa (3,670 m). Participants received either extended-release acetazolamide (500 mg once daily) or placebo, starting 2 days before ascent and continuing for 4 days postarrival. The primary endpoint was AMS incidence (Lake Louise Score [LLS] ≥3 with headache). <b><i>Results:</i></b> Among 284 completers, AMS incidence was significantly lower with acetazolamide (36.9% vs. 55.9%, <i>p</i> = 0.0013). Moderate/severe AMS (LLS > 5) was also reduced (9.9% vs. 24.5%, <i>p</i> = 0.0012). SpO₂ levels were consistently higher in the treatment group (<i>p</i> < 0.0001). Adverse events, including paresthesia and polyuria, were mild and self-limiting. <b><i>Conclusion:</i></b> Once-daily extended-release acetazolamide (500 mg) effectively prevents AMS and is well-tolerated in healthy Asian individuals. This regimen may enhance adherence and serve as a practical prophylactic option for high-altitude travelers.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Helicopter Rescue at Very High Altitude: Recommendations of the International Commission for Mountain Emergency Medicine (ICAR MedCom) 2025.","authors":"Kyle McLaughlin, Charley Shimanski, Ken Zafren, Ian Jackson, Gerold Biner, Maurizio Folini, Andreas Hermansky, Eric Ridington, Peter Hicks, Giacomo Strapazzon, Marika Falla, Alastair Hopper, Dave Weber, Ryan Jackson, Hermann Brugger","doi":"10.1177/15578682251375408","DOIUrl":"https://doi.org/10.1177/15578682251375408","url":null,"abstract":"<p><p>McLaughlin, Kyle, Charley Shimanski, Ken Zafren, Ian Jackson, Gerold Biner, Maurizio Folini, Andreas Hermansky, Eric Ridington, Peter Hicks, Giacomo Strapazzon, Marika Falla, Alastair Hopper, Dave Weber, Ryan Jackson, and Hermann Brugger. Helicopter rescue at very high altitude: Recommendations of the International Commission for Mountain Emergency Medicine (ICAR MedCom) 2025. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background:</i></b> Helicopter mountain rescue is highly effective. However, air rescue operations at very high altitude (VHA), above 3500 m, are inherently hazardous because of challenging topography, dynamic weather, and hypobaric hypoxic environment. Currently, no established international guidelines exist for helicopter rescues at VHA. <b><i>Methods:</i></b> We conducted a narrative review of existing literature, supplemented by expert opinions from helicopter pilots, physicians, and rescuers actively engaged in VHA rescues. These recommendations were approved by the International Commission of Alpine Rescue (ICAR) Medical Commission and endorsed by the ICAR Air Rescue Commission. <b><i>Discussion:</i></b> We identified 19 key factors to consider, including operational parameters, ground site management, pilot and rescuer safety protocols, and psychological factors to assist air rescue programs in developing pre-mission, mission, and post-mission plans for helicopter rescue missions at VHA. <b><i>Conclusions:</i></b> By implementing the recommendations outlined in this article, helicopter rescue teams operating at VHA can improve response capabilities and minimize risks.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145033200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ignoble Gas: The Questionable Role of Xenon in Rapid Ascents of Mount Everest.","authors":"Giorgio Manferdelli, Marc M Berger, Andrew M Luks","doi":"10.1177/15578682251377419","DOIUrl":"https://doi.org/10.1177/15578682251377419","url":null,"abstract":"<p><p>Manferdelli, Giorgio, Marc M Berger, and Andrew M Luks.Ignoble Gas: The Questionable Role of Xenon in Rapid Ascents of Mount Everest. <i>High Alt Med Biol.</i> 00:00-00, 2025.-Beyond the logistical, technical, and physiological challenges associated with climbing extremely high mountains such as Mount Everest, an important feature of such expeditions is their long duration. Among the strategies used in recent years to reduce expedition duration, one particularly novel approach was implemented during Everest expeditions in 2024 and 2025-inhalation of the noble gas xenon prior to the expeditions. Despite the tremendous attention this approach received in the media, significant questions remain as to whether it is truly effective at improving acclimatization and shortening the duration of expeditions. This review examines this issue in greater detail. After providing background information on xenon, the review examines potential rationales for xenon's use in the mountains, assesses the risks of xenon administration, and considers other aspects of the expedition protocol that likely affected the odds of summit success. Based on this analysis, there is no basis for widespread implementation of xenon inhalation at this time. Evidence of benefit is lacking, and there are strong reasons to believe other aspects of the expedition protocol contributed significantly to the expeditions' outcomes. Much further research on these questions is warranted before any more climbers should engage in this potentially risky practice.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145033138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute High-Altitude Exposure Increases Transcription of Tricarboxylic Acid Cycle Enzymes in Human Duodenal Biopsies.","authors":"Patrick-Pascal Strunz, Raphael N Vuille-Dit-Bille, Heiko Fruehauf, Mark Fox, Andreas Geier, Marco Maggiorini, Max Gassmann, Thomas A Lutz, Oliver Goetze","doi":"10.1177/15578682251374980","DOIUrl":"https://doi.org/10.1177/15578682251374980","url":null,"abstract":"<p><p><b><i>Background:</i></b> A recent study of our group quantifying ¹³C-octanoate metabolism in HA (Capanna Margherita [MG]/4,559 m) showed that acute HA exposure might lead to an increase of the lipolytic and CO₂-producing pathways. <b><i>Objective:</i></b> To further test this hypothesis, we investigated intestinal biopsies from the same participants from simultaneously performed endoscopy studies for changes of mRNA-expression levels of the beta-oxidation enzymes and the decarboxylating tricarboxylic acid cycle (TCA) enzymes. <b><i>Methods:</i></b> Duodenal biopsies of 16 subjects exposed to HA were sampled via gastro-duodenoscopy at Zurich (baseline ZH, 490 m), on day 2 (MG2) and on day 4 at HA (MG4). After mRNA extraction, quantitative real-time polymerase chain reaction was performed to assess mRNAs expression of TCA cycle enzymes as well as beta-oxidation enzymes. <b><i>Results:</i></b> Aconitase mRNA levels increased early (MG2 vs. ZH, <i>p</i> < 0.05) and were still higher at day 4 compared with ZH (MG4 vs. ZH, <i>p</i> < 0.05). Isocitrate dehydrogenase (DH) levels increased with time spent at 4,559 m (MG4 vs. ZH, <i>p</i> < 0.01). The remaining TCA cycle and beta-oxidation enzymes investigated tended to higher values at HA but without reaching significance. <b><i>Conclusion:</i></b> We conclude that acute exposure to HA leads to increased transcription of aconitase and isocitrate DH in the duodenal mucosa due to hypobaric hypoxia exposure.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144951957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Acute High-Altitude Exposure on the Timing of Tranexamic Acid Administration in Rabbits with Traumatic Hemorrhagic Shock.","authors":"Zhen Liu, Chao Nie, Lijia Yuan, Hui Jiang, Chuanchuan Liu, Yi Zhang, Minghua Liu","doi":"10.1177/15578682251375921","DOIUrl":"10.1177/15578682251375921","url":null,"abstract":"<p><p>Liu, Zhen, Chao Nie, Lijia Yuan, Hui Jiang, Chuanchuan Liu, Yi Zhang, and Minghua Liu.Impact of Acute High-Altitude Exposure on the Timing of Tranexamic Acid Administration in Rabbits with Traumatic Hemorrhagic Shock. <i>High Alt Med Biol.</i> 00:00-00, 2025. <b><i>Background:</i></b> Acute exposure to high altitude (≤3 days)-induced physiological changes may shorten the therapeutic time window for tranexamic acid (TXA) administration after traumatic hemorrhagic shock (THS). This study aims to compare the differences in the TXA therapeutic time window between THS patients with acute high-altitude exposure and those in low-altitude regions. <b><i>Methods:</i></b> Forty-two anesthetized rabbits were divided into three groups: low-altitude THS (l-THS), high-altitude sham, and high-altitude THS. All h-THS groups were housed for 3 days in 10% oxygen chambers (simulating 5,000 m altitude) before experimentation. THS models were established by reducing mean arterial pressure from 105 to 55 mmHg through blood loss combined with left tibiofibular fracture. Animals received single-dose TXA (90 mg/kg) with the following subgroups: l-THS-2h and l-THS-3h (TXA administered 2 hours/3 hours post-THS), h-THS-1h, h-THS-2h, h-THS-3h and h-THS-4h (TXA administered 1 hours/2 hours/3 hours/4 hours post-THS). Comparative analyses included hemodynamic parameters, complete blood counts, coagulation-fibrinolysis function, endothelial injury markers, inflammatory cytokines, and pulmonary histopathological changes. <b><i>Results:</i></b> High-altitude exposure required less blood loss to achieve THS compared with low-altitude conditions (51.00 ± 2.45 ml vs. 59.60 ± 3.65 ml, <i>p</i> < 0.05). At 6 hours post-THS, compared to the l-THS-2h group [TIC risk (INR:1.34 ± 0.09), anaerobic oxidation levels, inflammatory response levels, and lung injury score (1.8 (1.0, 2.0))], the l-THS-3h group [INR:1.51 ± 0.08; 2.6 (2.0, 3.0)], h-THS-2h group [1.45 ± 0.06; 2.8 (2.0, 3.5)], h-THS-3h group [INR:1.75 ± 0.11; 5.6 (4.5, 6.5)], and h-THS-4h group [INR:1.99 ± 0.06; 6.2 (6.0, 6.5)] all showed significantly higher values. For the same observational indicators, compared with the l-THS-3h group, the h-THS-1h group had lower values, while the h-THS-3h and h-THS-4h groups showed higher values. No statistically significant differences were observed between the l-THS-2h and h-THS-1h groups, or between the l-THS-3h and h-THS-2h groups for all parameters. <b><i>Conclusion:</i></b> The optimal time window for TXA administration in traumatic hemorrhagic shock may be shorter at high altitude compared with low-altitude area. These findings could influence therapeutic guidelines for TXA administration at high altitudes in humans.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144951902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}