High altitude medicine & biology最新文献

{"title":"Gut Microbiota Dynamics During Extreme Altitude Climbing: A Longitudinal Case Report.","authors":"Jesús Álvarez-Herms, Kilian Jornet, Martin Burtscher, Adriana González, Adrián Odriozola","doi":"10.1177/15578682251396447","DOIUrl":"10.1177/15578682251396447","url":null,"abstract":"<p><p>Álvarez-Herms, Jesús, Kilian Jornet, Martin Burtscher, Adriana González, and Adrián Odriozola. Gut microbiota dynamics during extreme altitude climbing: a longitudinal case report. <i>High Alt Med Biol.</i> 27:123-127, 2026.-The present case study would explore the acute changes of gut microbiota (GM) and some physiological responses of a world-class mountaineer during a 4-week stay at altitudes between 3,600 and 4,200 m, with four rapid ascents to different extreme altitudes, that is, 6,700, 7,000, 8,000, and 8,400 m. Severe hypoxemia, hyperglycemia, ketoacidosis, and sympathetic dominance were found to be proportionally higher with increasing altitude. Thus, the GM changed during the acclimatization period, decreasing bacterial diversity (Shannon index from 5.88 to 4.56). Remarkably, during the third week, a transient increase of the pathogenic bacteria <i>Ruminococcus gnavus</i> (+2,800%) was found. Thus, this significant elevation coincided with the impaired systemic health and gastrointestinal and respiratory complications. In conclusion, the present exploratory study found that a favorable and healthy GM profile, characterized by elevated mucolytic and short-chain fatty acids-producing bacteria, may improve hypoxic tolerance, reduce the risk of developing gut leakage syndrome and systemic endotoxemia, and protect against acute mountain sickness.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"123-127"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145564019","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":"Rescue at Extreme Altitude: Managing the Ethical Considerations in the Language of Risk Management. An International Commission for Alpine Rescue Position Paper.","authors":"John Ellerton, Alison Sheets, Kyle McLaughlin, Peter Paal","doi":"10.1177/15578682251400732","DOIUrl":"10.1177/15578682251400732","url":null,"abstract":"<p><p>Ellerton, John, Alison Sheets, Kyle McLaughlin, and Peter Paal. Rescue at Extreme Altitude: Managing the Ethical Considerations in the Language of Risk Management. An International Commission for Alpine Rescue Position Paper. <i>High Alt Med Biol.</i> 27:117-122, 2026.Rescue from altitude has additional risks that require specialist knowledge, skills, and ability. Currently, rescue at extreme altitude (>5,500 m) is provided largely by ad-hoc teams responding to a need. The ethics of performing such rescues is controversial, and media coverage rarely considers the complexity of the environment. Organized mountain rescue teams have established processes to manage risk and their conduct to provide a professional service that changes the language of ethical decision-making into a practical, nuanced risk and crew resource management format. The International Commission for Alpine Rescue, along with the International Society of Mountain Medicine, has produced scientific papers on rescue at very high altitude and a position paper on the ethics of extreme altitude rescue. The aim is to improve the safety and outcomes of all rescues at altitude. The position paper, presented here, is targeted principally at those involved in extreme altitude rescue. Organized mountain rescue developed from ad-hoc rescue in response to a need; the same is likely to occur for extreme altitude rescue. Altitude is only one of the risk factors, and the knowledge of modern mountain rescue processes could aid in the advancement of extreme altitude rescue.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"117-122"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145582125","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":"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":"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> 27:93-99, 2026.</p><p><strong>Background: </strong>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.</p><p><strong>Methods: </strong>An anonymous survey of mountaineers who have attempted to climb mountains >6,000 m in the past 20 years.</p><p><strong>Results: </strong>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.</p><p><strong>Conclusions: </strong>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":"93-99"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","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":"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> 27:79-86, 2026.</p><p><strong>Background: </strong>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.</p><p><strong>Methods: </strong>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.</p><p><strong>Results: </strong>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.</p><p><strong>Conclusion: </strong>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":"79-86"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","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}

{"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":"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> 27:107-116, 2026.</p><p><strong>Background: </strong>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.</p><p><strong>Methods: </strong>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.</p><p><strong>Discussion: </strong>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.</p><p><strong>Conclusions: </strong>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":"107-116"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","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":"<i>Letter:</i> Vestibular/Ocular Motor Screening as a Novel Test of Cognition at Altitude.","authors":"Andrew Huff, Ramsay Hafer, Lara Phillips","doi":"10.1177/15578682251398395","DOIUrl":"10.1177/15578682251398395","url":null,"abstract":"","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"128-129"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145495299","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":"A Retrospective Analysis of Altitude Illness at the Himalayan Rescue Association Aid Post Manang (2018-2023).","authors":"Suraj Shrestha, Sanjeev Kharel, Suman Acharya, Gobi Basyal, Sanjeeb S Bhandari","doi":"10.1177/15578682251376256","DOIUrl":"10.1177/15578682251376256","url":null,"abstract":"<p><p>Shrestha, Suraj, Sanjeev Kharel, Suman Acharya, Gobi Basyal, and Sanjeeb S. Bhandari. A retrospective analysis of altitude illness at the Himalayan Rescue Association aid post manang (2018-2023). <i>High Alt Med Biol.</i> 27:87-92, 2026.</p><p><strong>Introduction: </strong>The Himalayan Rescue Association (HRA) in Nepal has been operating high-altitude aid posts in the Himalayas to alleviate illnesses in hikers and locals with a focus on acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE), as well as other common medical problems. This study examines the altitude-related illnesses occurring between 2018 and 2023 at the HRA Manang aid post.</p><p><strong>Materials and methods: </strong>A retrospective study analyzing the medical records of HRA Manang from 2018 to 2023 was conducted. Demographics and diagnoses were documented, and the Lake Louise Score (LLS) was calculated for AMS cases. The frequency of altitude-related illness was compared among trekkers with/without a good ascent profile.</p><p><strong>Results: </strong>During the study period, a total of 2,904 people visited the aid post, with 337 (11.6%) suffering from altitude-related illnesses, including 274 AMS, 40 HAPE, 11 HACE, and 12 concurrent HAPE with HACE, with 58.8% of cases seen in the fall season. Most were adults, non-Nepali (70.3%), of which only 4.5% comprised the pediatric population. The majority of AMS cases were mild (70.6%) (LLS ≤5), while 17.2% had moderate to severe AMS. Almost one-third (28.2%) of cases had rapid ascent (elevation >500/day above 2,500 m), with a majority of 67.4% being Nepali compared to non-Nepali (<i>p</i> < 0.05). The proportion of HACE and concurrent HAPE with HACE was significantly higher among those with rapid ascent profiles. About 36.20% of cases with altitude-related illness had taken prophylactic acetazolamide, which was considerably lower among Nepali patients (<i>p</i> < 0.001). Motor vehicle evacuation (86.7%), followed by helicopter evacuation (13.3%), was used for those requiring immediate descent.</p><p><strong>Conclusion: </strong>Altitude illness is a common problem among trekkers in the Annapurna region of Nepal. More effort should be focused on educating high-altitude travelers to reduce the risk of these problems.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"87-92"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144992332","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":"Ischemic Stroke in Young Adults at High Altitude: Different Etiology and Pathogenesis.","authors":"Mingyu Tang, Zhuoga Cidan, Yang Ci, Yaxiong Hu, Yuhua Zhao, Fei Han, Lixin Zhou, Jun Ni","doi":"10.1177/15578682251388568","DOIUrl":"10.1177/15578682251388568","url":null,"abstract":"<p><p>Tang, Mingyu, Zhuoga Cidan, Yang Ci, Yaxiong Hu, Yuhua Zhao, Fei Han, Lixin Zhou, and Jun Ni. Ischemic stroke in young adults at high altitude: different etiology and pathogenesis. <i>High Alt Med Biol.</i> 27:100-106, 2026.</p><p><strong>Introduction: </strong>Current knowledge indicates that exposure to high altitude increases the risk of ischemic stroke. However, its impact on ischemic stroke in young adults is still unknown.</p><p><strong>Methods: </strong>This two-center retrospective study analyzed 451 patients aged 18-50 years who experienced a first-ever ischemic stroke and were hospitalized at Peking Union Medical College Hospital (44 m) or Tibet Autonomous Region People's Hospital (3,650 m) between 2013 and 2021. Clinical characteristics, stroke etiology, and the results of auxiliary tests were compared.</p><p><strong>Results: </strong>A total of 451 patients were enrolled in this study, with a median age of 43, and 66.5% were male. At high altitude, hypertension (41.0% vs. 52.7%, <i>p</i> < 0.05) and diabetes mellitus (11.8% vs. 25.9%, <i>p</i> < 0.05) were less prevalent, whereas small-vessel occlusion stroke (21.7% vs. 8.0%, <i>p</i> < 0.01) was more common. Elevated levels of D-dimer (51.5% vs. 39.3%, <i>p</i> < 0.05) and hemoglobin (11.8% vs. 0%, <i>p</i> < 0.01) were observed more at high altitude. High altitude was associated with small-vessel occlusion stroke (odds ratio [OR] = 3.26, 95% confidence interval [CI] = 1.56-6.82, <i>p</i> < 0.01).</p><p><strong>Conclusion: </strong>The etiology of ischemic stroke in young adults at high altitude differs from that at low altitude. The higher frequency of hyperhemoglobinemia and hypercoagulable status suggests a distinct pathophysiological mechanism resulting from chronic high-altitude exposure.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"100-106"},"PeriodicalIF":1.4,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145291960","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":"Correlation of Uterine Blood Flow in the First Trimester of Pregnancy and Birth Weight at Term in High Altitude.","authors":"Wilfredo Villamonte-Calanche, Marco Antonio Salazar-Zegarra, Franklin Miranda-Solis, María Jerí-Palomino","doi":"10.1177/15578682261444625","DOIUrl":"https://doi.org/10.1177/15578682261444625","url":null,"abstract":"<p><p>Villamonte-Calanche, Wilfredo, Marco Antonio Salazar-Zegarra, Franklin Miranda-Solis, and María Jerí-Palomino. Correlation of uterine blood flow in the first trimester of pregnancy and birth weight at term in high altitude. <i>High Alt Med Biol.</i> 00:00-00, 2026.</p><p><strong>Objective: </strong>To determine the correlation between total uterine artery flow (UtAQ) at the end of the first trimester of pregnancy and birth weight (BW) at term at 3,400 m altitude.</p><p><strong>Methods: </strong>Prospective study, conducted at 3,400 m altitude in 210 women who underwent routine ultrasound evaluation. The inclusion criteria were singleton pregnancy between 11 and 14 weeks + 1 day, crown-rump length between 45 and 84 mm, born and raised at high altitude (native), and without pathology. The outcome was BW, expressed as a Z score. Variables such as UtAQ, uterine artery (UtA) diameters, age, body mass index, and mean arterial pressure, among others, were evaluated.</p><p><strong>Results: </strong>After applying the inclusion criteria, 203 pregnant women were evaluated, out of a total of 210 women. The average diameter of UtA was 0.27 cm, and the total bilateral UtA blood flow was 305.8 ml/min. A significant correlation was found between BW and UtAQ (rho = 0.15, <i>p</i> = 0.033), with a higher association for the left UtA (rho = 0.19, <i>p</i> = 0.007). Similarly, BW was positively correlated with the average diameter of the UtAs (r = 0.21, <i>p</i> = 0.003) and the association was stonger for the left UtA (r = 0.19, <i>p</i> = 0.006).</p><p><strong>Conclusion: </strong>In low-risk singleton pregnancies among native women living at high altitude, a correlation was observed between UtAQ and term BW, with the highest association found between BW and the diameter and UtAQ of the left UtA.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"15578682261444625"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147814296","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":"Time-Dependent Effects of Chronic Hypoxic Exposure on Microarchitecture of Different Skeletal Sites in Mice.","authors":"Yanli Chen, Suying Zhu, Doudou Hao, Zhiyou Shi, Yang Zhong, Suyuan Wang, Yunhong Wu","doi":"10.1177/15578682261445399","DOIUrl":"https://doi.org/10.1177/15578682261445399","url":null,"abstract":"<p><p>Chen, Yanli, Suying Zhu, Doudou Hao, Zhiyou Shi, Yang Zhong, Suyuan Wang, and Yunhong Wu. Time-Dependent Effects of Chronic Hypoxic Exposure on Microarchitecture of Different Skeletal Sites in Mice. <i>High Alt Med Biol.</i> 00:00-00, 2026.-High-altitude hypoxia accelerates bone loss by disrupting bone metabolic homeostasis. Currently, hypoxic effects on bone and their link to exposure time remain undefined. This study aimed to systematically evaluate the dynamic effects of chronic hypoxic exposure on bone homeostasis and bone microstructure in different skeletal sites through <i>in vivo</i> and <i>in vitro</i> experiments. Male C57BL/6J mice were exposed to 5,500 m simulated hypoxia for 16 weeks. Micro-CT analyzed cervical (C3-C4), lumbar (L4-L6) vertebrae, and femurs. Histopathological analysis assessed bone tissue and multiorgan pathology. <i>In vitro</i> experiments, a 5% hypoxic culture system was established to detect the proliferation and differentiation capabilities of MC3T3-E1 osteoblasts. After 12 weeks of hypoxic exposure, compared with the control group, the trabecular separation (Tb.Sp) of the mouse femur was significantly increased, and the bone mineral content was significantly decreased. After 16 weeks of exposure, the trabecular bone volume/tissue volume (Tb.BV/TV) and bone mineral density of the cervical vertebrae, lumbar vertebrae, and femurs were significantly reduced. H&E staining showed osteoblasts in multiple bones of hypoxic mice shifted to quiescent states, and long-term hypoxia induced multi-organ damage (pulmonary, renal, colonic, skeletal muscle). 5% hypoxia significantly downregulated collagen type I and alkaline phosphatase (ALP) mRNA levels in MC3T3-E1 cells, inhibited ALP activity and mineralized nodule formation, and reduced osteoblast differentiation capacity. Chronic hypoxic exposure induces bone loss in multiple skeletal sites of mice in a time-dependent manner, with femur showing significantly higher sensitivity to hypoxic exposure than the cervical and lumbar vertebrae. The underlying mechanism may be related to hypoxia inhibiting osteoblast function and disrupting the balance of bone metabolism. Long-term hypoxia also causes pathological damage to multiple organs. This study provides evidence for clarification of the pathological mechanism of hypoxic bone injury and lays a foundation for the subsequent development of targeted intervention strategies for hypoxia-related bone diseases.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"15578682261445399"},"PeriodicalIF":1.4,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147769978","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}