High altitude medicine & biology最新文献

Millet, Grégoire P, Philippe Connes.Sickle Cell Trait is a Risk Factor for Another Form of Altitude Illness. High Alt Med Biol. 00:00-00, 2025.-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.

Álvarez-Herms, Jesús, Kilian Jornet, Martin Burtscher, Adriana González, and Adrián Odriozola. Gut microbiota dynamics during extreme altitude climbing: A longitudinal case report. High Alt Med Biol. 00:00-00, 2025.-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 Ruminococcus gnavus (+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.

Tang, gang, chuan Li, Bao-mei Song, Shuang Li, Qiang Wang, and 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. 00:00-00, 2025. 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.

Wu, Tianzhun, Ruofan Li, 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. 00:00-00, 2025. 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, 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. High Alt Med Biol. 00:00-00, 2025. Introduction: 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. Methods: 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. Results: 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%, p < 0.05) and diabetes mellitus (11.8% vs. 25.9%, p < 0.05) were less prevalent, whereas small-vessel occlusion stroke (21.7% vs. 8.0%, p < 0.01) was more common. Elevated levels of D-dimer (51.5% vs. 39.3%, p < 0.05) and hemoglobin (11.8% vs. 0%, p < 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, p < 0.01). Conclusion: 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.

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. High Alt Med Biol. 00:00-00, 2025. Background: 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. Methods: An anonymous survey of mountaineers who have attempted to climb mountains >6,000 m in the past 20 years. Results: 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. Conclusions: 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.

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. High Alt Med Biol. 00:00-00, 2025. Introduction: 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. Methods: 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. Results: We found several impacts of high altitude on immune cell populations, including shifts in monocytes from classical to intermediate (p = 0.004 after 1 night at high altitude [HA1], and p < 0.001 after 2 nights at high altitude [HA2]) and nonclassical subsets (p = 0.013 on HA2), and increases in total B cells (p = 0.001 on HA2, p = 0.004 [HA3]). An effect of altitude was found for neutrophil CD15 expression (p < 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 (R² = 0.79, p = 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.

Introduction: 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. Methods: 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). Results: 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). Conclusions: 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.

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. High Alt Med Biol. 00:00-00, 2025. Background and Objectives: 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. Methods: 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. Results: We identified a potential association between HAA and a decreased risk of pancreatic cancer (odds ratio [OR] = 8.94e-8, p = 0.011) and cervical cancer (OR = 8.04e-6, p = 0.005). In contrast, HAA showed a potential link to an increased risk of esophageal cancer (OR = 3230.25, p = 0.03) and hepatocellular carcinoma (OR = 2080.07, p = 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. Conclusion: These findings highlight HAA's complex role in tumor susceptibility and provide a genetic framework for understanding tumor disparities in high-altitude regions.