High altitude medicine & biology最新文献

Wu, Tianzhun, Ruofan Li, Qingfeng Song, Li Xu, Chaofan Shi, Juanjuan Liu, Xing Gao, Shilin Huang, Shizhou Li, Dandan Zeng, Wenfeng Luo, Yan Lin, Jiazhou Ye, Minggen Hu, and Rong Liang. Using Mendelian randomization to dissect the relationship between high-altitude adaptation and liver diseases/traits. High Alt Med Biol. 27:42-48, 2026.

Background: It has been reported that high-altitude adaptation (HAA) and susceptibility to multiple liver diseases/traits differ between individuals at higher altitudes compared to those at lower altitudes. To investigate this association, we conducted a Mendelian randomization study.

Methods: To investigate the association between HAA and liver diseases/traits, we utilized genome-wide association studies focusing on East Asian ancestry. Our study included six liver disease-related phenotypes: autoimmune hepatitis, chronic hepatitis B, chronic hepatitis C, acute hepatitis by hepatitis A virus, hepatic cancer, and hepatic bile duct cancer, as well as five liver traits: alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase (GGT), and total bilirubin. A Bonferroni-corrected significance was set at p < 4.55 × 10^-3.

Results: Our study identified a significant genetically predicted causal impact of HAA on GGT (odds ratio [OR] = 1.601; 95% confidence interval [CI] = 1.204-2.129; p = 0.0012). Interestingly, the association remained statistically significant even when the causal direction was reversed, with GGT predicting HAA (OR = 1.01; 95% CI = 1.003-1.011; p = 0.0013). Both findings surpassed the Bonferroni-corrected threshold.

Conclusion: In conclusion, our study provides suggestive evidence for a potentially causal bidirectional association between HAA and GGT. These novel insights may inform the development of targeted preventive measures and therapeutic interventions for liver diseases and high-altitude adaptation.

Tang, Xu-gang, Xiu-chuan Li, Bao-mei Song, Shuang Li, Qiang Wang, and Yong-jian Yang. Association between decreased pulse oximetry and acute mountain sickness upon rapid ascent to 4,086 m among young Chinese men. High Alt Med Biol. 27:49-46, 2026.

Background: Research on predicting acute mountain sickness (AMS) based on the decreased pulse oximeter saturation (SpO₂) during rapid train travel to high altitudes is limited and inconsistent. We aimed to assess whether lower SpO₂ levels are associated with AMS in a young Chinese male population following a rapid ascent to high altitude by train.

Methods: The study involved 375 young Chinese men with a median age of 21. The participants spent 43 hours ascending from an altitude of 400 m to 4,086 m, including 41 hours by train and 2 hours by car. They were divided into AMS+ and AMS- groups based on the Lake Louise AMS score (LLS) after being exposed to 4,086 m for 24 hours. Participants' SpO₂ and heart rate (HR) were measured. AMS was assessed using the LLS. Data were analyzed using Spearman's correlation, logistic regression, and receiver operating characteristic (ROC) analysis.

Results: At 4,086 m, the overall AMS prevalence was 31%. The HR was significantly higher in the AMS+ group compared to the AMS- group. Conversely, SpO₂ was lower in the AMS+ group. Correlation analysis showed that LLS was positively correlated with HR and negatively correlated with SpO₂. Adjusted logistic regression identified lower SpO₂ (OR = 0.909, 95% CI: 0.867-0.953, p < 0.001) and HR (OR = 1.031, 95% CI: 1.010-1.052, p < 0.01) as independent risk factors for AMS. ROC analysis indicated that lower SpO₂ is a significant marker for diagnosing moderate to severe AMS. The optimal cut-off value for SpO₂ was 81.5%, with a sensitivity of 66.7%, a specificity of 75.7%, and an AUC of 0.724, with lower and upper confidence limits of 0.555 and 0.893, respectively.

Conclusion: This study suggests that lower SpO₂ levels are associated with AMS in young Chinese men who rapidly ascend to 4,086 m, primarily by train.

Millet, Grégoire P, and Philippe Connes. Sickle cell trait is a risk factor for another form of altitude illness. High Alt Med Biol. 27:57-59, 2026.-Acute mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema have been widely investigated. In this letter, we claim that beyond these three altitude illnesses, one cannot rule out an additional serious concern related to altitude exposure in a particular population; the individuals with sickle cell trait.

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.

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. High Alt Med Biol. 00:00-00, 2025.

Background: 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.

Methods: 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.

Discussion: 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.

Conclusions: By implementing the recommendations outlined in this article, helicopter rescue teams operating at VHA can improve response capabilities and minimize risks.

Marzola, Manuel, Massimiliano Marazzato, Roberto Nutini, Adriano Di Marzio, Francesca Baroli, Manuel Paolucci, Matteo De Angelis, Joanna Giuliano, Ambra Menichelli, Guglielmo Sferrati, Carmen Santangelo, Danilo Bondi, Gerardo Bosco, and Vittore Verratti. Effects of OXXYSLAB probiotic supplementation on blood oxygenation and hypoxic symptoms in healthy individuals: A controlled normobaric hypoxia trial. High Alt Med Biol. 00:00-00, 2026.

Background: OXXYSLAB, a high-dose, multi-strain probiotic, has shown promise in pathological hypoxemia but remains untested under acute normobaric hypoxia (NH) in healthy volunteers. We evaluated whether OXXYSLAB alters peripheral oxygen saturation (SpO₂) and alleviates hypoxia-related symptoms in healthy adults exposed to NH.

Methods: In two randomized, double-blind, crossover phases, young adults were exposed to ∼13.5% inspired O₂ for 1 hour (Phase 1: n = 12, 21.6 ± 1.3 years, body mass index [BMI] = 23.2 ± 2.8 kg/m²) or 40 minutes (Phase 2: n = 20, 21.7 ± 1.5 years, BMI = 22.9 ± 3.2 kg/m²). Participants received either a single (8 × 10¹¹ colony-forming unit [CFU]) or double (1.6 × 10¹² CFU) dose of OXXYSLAB or matched placebo in randomized order.

Results: NH induced the expected SpO₂ decrease (Phase 1: 90.0 ± 2.1%; Phase 2: 86.7 ± 2.9%), with no significant effect of probiotic supplementation on SpO₂. In Phase 1, a trend toward lower heart rate (Δ = -3.2 bpm) under OXXYSLAB approached significance (p = 0.053); no effect was seen in Phase 2. Notably, headache incidence under probiotic conditions was reduced by 50% (Phase 1) and 62.5% (Phase 2) compared to placebo (p = 0.046 and p = 0.059, respectively).

Conclusion: While OXXYSLAB did not enhance systemic oxygenation during acute NH, it significantly attenuated headache, a common symptom of hypoxia. Further research should assess its efficacy under prolonged or clinical hypoxemic conditions.

Du, Tianjing, Haoqing Shi, Linlin Liu, and Zeyu Yang. The mediating role of cognitive function in the relationship between acute high-altitude stress and casualty care capability following rapid ascent. High Alt Med Biol. 00:00-00, 2026.

Background: The impact of high-altitude rescue missions on medical personnel's cognitive function and casualty care capabilities remains unclear.

Methods: This multicenter, randomized, sham-controlled clinical trial established high-altitude intervention (HAI), high-altitude (HA), and sea level (SL) groups (n = 92 per group). The HAI group received an integrated cognitive-stress management training, and the HA group implemented a sham training regimen before rapid ascent to high altitude (RAHA). The SL group served as a blank control group. Primary outcomes included casualty care capability score, plasma cortisol level, and cognitive ability score. Longitudinal mediation analysis examined the role of cognitive function in stress and casualty care capabilities.

Results: In the HA group, cognitive ability mediated strong negative indirect effects at 24 hours, alongside a positive direct effect of stress. At 48 hours, the negative indirect effect remained dominant, whereas the direct effect of stress was not significant. At 72 hours, the indirect effect weakened but remained significant, whereas the direct effect of stress became significantly negative. By 96 hours, the indirect effect disappeared, with the total effect explained by stress. In the HAI group, the total and indirect effects were significant at 24 and 48 hours, whereas the direct effects were not. At 72 and 96 hours, no effects were statistically significant.

Conclusion: During the initial phase of RAHA, cognitive ability serves as a mediating factor through which stress impairs casualty care capabilities. Over time, the mediating effect of cognition gradually diminishes, while the direct negative impact of the stress response continues to strengthen. The integrated cognitive-stress training can effectively preserve cognitive function and mitigate the stress response, thereby enhancing medical personnel's casualty care capabilities.

Nimadeji, Yanna Cai, and Na Gao. Genetic adaptation to Tibetan high altitudes and hepatocellular cancer risk: integrative bidirectional Mendelian randomization and single-cell RNA sequencing analysis. High Alt Med Biol. 00:00-00, 2025.

Background: The unique genetic adaptations of Tibetans to high-altitude environments may influence disease susceptibility, including hepatocellular carcinoma (HCC).

Methods: We employed bidirectional two-sample Mendelian randomization (MR) using genome-wide association study summary statistics: high-altitude adaptation (HAA) data from Tibetan/non-Tibetan East Asians (n = 10,295) and HCC data from BioBank Japan (1,866 cases/195,745 controls). Instrumental variables were selected via genome-wide significance (p < 5 × 10^-8), with inverse variance-weighted random-effects models as primary analysis. MR-Egger regression analysis and Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) global analysis were used to evaluate the pleiotropic effect. Single-cell RNA sequencing from the Hepatocellular Carcinoma Database identified HAA-related differentially expressed genes (DEGs) in HCC tissues, followed by functional enrichment analysis.

Results: MR results demonstrated HAA as a causal risk factor for HCC (odds ratio = 2.15 × 10², 95% confidence interval = 1.57-2.96 × 10⁴, p = 0.032), with no reverse causality. Single-cell analysis revealed 23 HAA-associated DEGs in HCC, enriched in immune regulation, DNA metabolism, and cell growth pathways. Notably, genes such as EPAS1 and GCH1; Guanosine triphosphate, GTP, previously linked to Tibetan HAA, were found to be differentially expressed in HCC tissues.

Conclusion: This study provides statistical and genetic evidence that HAA is a causal risk factor for HCC in Tibetans. The identification of HAA-related genes in HCC tissues offers new insights for targeted prevention and treatment strategies in Tibetan populations.

Barg, Taylor, Jaclyn Walker, Samara Levine, David Ryan Ormond, and James P Maloney. Altered Mental Status at High Altitude: Obstructive Hydrocephalus Mimicking High Altitude Cerebral Edema (HACE). High Alt Med Biol. 00:00-00, 2025.-A 29-year-old female presented to a Colorado emergency department with amnesia, headache, confusion, and dysarthria after rapidly ascending a 4,404 m (14,267 ft) peak. Head CT revealed cerebral edema and hydrocephalus. She was hypotensive and required vasopressors prior to evacuation to a lower-altitude intensive care unit and received initial treatment for high-altitude cerebral edema (HACE) with dexamethasone. Imaging and clinical workup revealed obstructive hydrocephalus due to a colloid cyst with minimal radiographical evidence of cerebral edema except due to the compressive effects of hydrocephalus. She transiently developed stress-induced cardiomyopathy and mixed neurocardiogenic shock. This case emphasizes the importance of considering HACE mimics at high altitude triggered by hypoxia-mediated increases in intracranial pressure.

Wakeham, Denis J, Andrew R Tomlinson, Giorgio Manferdelli, Matthew M Howrey, Anna K Geib, Murugappan Ramanathan, Marcus Payne, Renie Guilliod, James Berry, Tony G Babb, Peter Hackett, Benjamin D Levine, and Christopher M Hearon. The Physiological and Altitude Lowering Effects of Different Supplemental Oxygen Flow Rates at Extreme Simulated Altitude: A Pilot Study. High Alt Med Biol. 00:00-00, 2025. Background: Approximately 80% of high-altitude climbers use supplemental oxygen >8,000 meters, yet optimal dosing strategies have not been established. Methodology: Therefore, in six unacclimatized individuals (34 ± 8 years; 2 F/4 M), we quantified the effects of supplemental oxygen flow rates (6, 4, 2, 1 and 0 L/min) using the SUMMIT Oxygen mask at 282 mmHg (rest and cycle ergometry: 60 and 120 Watts) and 253 mmHg (rest only) barometric pressure in a hypobaric chamber. We measured oxygen saturation (SpO₂) and gas fractions in the mask during 4-minute exposures to each flow rate. Results: Resting at 282 mmHg, SpO₂ (6 L/min: 99% ± 0%; 0 L/min: 70% ± 8%, p < 0.001) and mean inspired oxygen fraction decreased (6 L/min: 65.87% ± 14.11%; 0 L/min: 21.50% ± 0.44%, p < 0.001) with lowering of supplemental oxygen. Exercise further decreased SpO₂ and oxygen fractions across all flow rates at 282 mmHg. At 253 mmHg, SpO₂ followed a similar trend to data collected at 282 mmHg (6 L/min: 96% ± 2%; 4 L/min: 93% ± 3%; 2 L/min: 87% ± 3%; 1 L/min: 71% ± 0%; 0 L/min: 66% ± 9%). Furthermore, at rest at 253 mmHg, 2 L/min of supplemental oxygen lowered the equivalent altitude to 4,489 meters. Conclusion: All unacclimatized participants were able to tolerate 253 mmHg at rest on as little as 2 L/min of supplemental oxygen.