High altitude medicine & biology最新文献

Yu Liu, Zhengyang Zhang, Yongting Luo, Peng An, Jingyi Qi, Xu Zhang, Shuaishuai Zhou, Yongzhi Li, Chong Xu, Junjie Luo, and Jiaping Wang. Product of traditional Chinese medicine longgui yangxinwan protects the human body from altitude sickness damage by reducing oxidative stress and preventing mitochondrial dysfunction. High Alt Med Biol. 00:00-00, 2024. Background: Plateau reaction, caused by high-altitude exposure, results in symptoms like headaches, dyspnea, palpitations, fatigue, shortness of breath, and insomnia due to reduced oxygen levels. Mitochondria are crucial for high-altitude acclimatization as they regulate oxygen metabolism and cellular energy, reducing oxidative stress and maintaining bodily functions. Methods: The study participants were randomly divided into placebo group, Rhodiola group and longgui yangxinwan (Original name: taikong yangxinwan) group, with 20 people in each group. Three groups of subjects were sampled at three time points (PI: pre-intervention; P-D1: high-altitude day 1; P-D7: high-altitude day 7), and blood pressure, blood oxygen, heart rate, hemoglobin, and red blood cell count were measured. The ATP content, mitochondrial DNA copy number, expression of mitochondria-related genes, reactive oxygen species (ROS), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) levels, and mitochondrial morphology were measured in blood at each time point. Results: Our study results demonstrate that longgui yangxinwan keeps the selected human physiological indicators stable and prevents mitochondrial dysfunction in the high altitude. Mechanically, longgui yangxinwan decreases the level of ROS in human serum, whereas increases the activity of the antioxidant enzyme GSH-PX. At high-altitude day 1 (P-D1) and high-altitude day 7 (P-D7), ROS in the placebo group were 1.5 and 2.2-fold higher than those of the longgui yangxinwan group, respectively. In addition, longgui yangxinwan enhances ATP production capacity, restores the levels of mitochondrial respiratory chain complexes, and effectively maintains mitochondrial morphology and integrity. At P-D1 and P-D7, the ATP levels in the longgui yangxinwan group were 19-fold and 26-fold higher than those in the placebo group, respectively. Conclusions: Our study highlights longgui yangxinwan as a potential drug for protecting humans from high-altitude damage by reducing oxidative stress and preventing mitochondrial dysfunction.

Strickland, Brian, Elan Small, Mary Ryan, and Ryan Paterson. Effectiveness of continuous positive airway pressure in alleviating hypoxemia and improving exertional capacity at altitude. High Alt Med Biol. 00:000-000, 2024. Introduction: Decreased oxygen saturation and exercise tolerance are commonly experienced at high altitude. Continuous positive airway pressure (CPAP) devices have become increasingly portable and battery powered, providing a potentially unique new therapeutic modality for treatment of altitude-related illnesses. This study evaluated the potential use of CPAP devices to improve and maintain oxygen saturation at altitude, both at rest and with exertion, to evaluate the feasibility of using this device at altitude. Methods: Subjects were taken to Mount Blue Sky and monitored while they hiked to the summit (4,350 m), maintaining a consistent level of exertion. Subjects hiked for 0.7 km both with and without CPAP set to 10 cmH₂O pressure. Continuous vital signs were collected during the hike and recovery period. Results: All subjects completed the hike wearing CPAP devices at a vigorous level of exertion. Mean oxygen saturation of the CPAP group (M = 83.8%, SD = 3.72) was significantly higher than that of the control group during exertion (M = 78.7%, SD = 2.97); p = 0.005. Recovery after exertion was quicker in the CPAP group than the control group. Three subjects experienced claustrophobia requiring a brief pause, but were able to complete their exercise trial without removing equipment or experiencing adverse events. When pauses from claustrophobia were excluded, there was no difference in completion time between the groups (p = 0.06). Conclusion: CPAP reliably improved oxygen saturation at rest and during vigorous exertion at high altitude. Its ability to correct hypoxemia, even with physical exertion, may prove useful after further study as a portable self-carried device to prevent and treat altitude-related illness, or to improve safety in high-altitude rescues.

Zhao, Linggong, Yujie Huang, and Xiaoling Tan. Preexisting hyperuricemia before high-altitude ascent is associated with a slower recovery of estimated glomerular filtration rate following descent. High Alt Med Biol. 00:00-00, 2024. Objectives: Hypoxia at high altitudes results in elevated uric acid (UA) and reduced estimated glomerular filtration rate (eGFR). However, the impact of a prolonged high-altitude sojourn on UA levels and renal function in patients with preexisting hyperuricemia warrants further exploration. The study was to investigate the eGFR and related factors in patients with preexisting hyperuricemia following exposure to high altitude. Methods: The study included 345 participants, who worked at a high altitude for 1 year. Anthropometric and laboratory indices were collected before ascent (i.e., baseline), as well as 20 and 80 days after descent. The participants were categorized into individuals with hyperuricemia (HUA) or normal uric acid (NUA) group based on the presence or absence of hyperuricemia at baseline. Results: No difference in baseline eGFR was observed between the two groups before ascend or on day 20 after descent (p > 0.05). However, on day 80, eGFR of the HUA group was lower compared with the NUA group (p < 0.05). Correlations existed between post-descent eGFR levels and variables, including sampling time, UA levels, total and direct bilirubin, and baseline grouping. Conclusions: After high-altitude exposure, the recovery of eGFR was delayed in participants with preexisting hyperuricemia. Preexisting hyperuricemia and high-altitude hypoxia jointly contribute to renal impairment.

Foster, Katharine, James D. Anholm, Gary Foster, Suman Thapamagar, and Prajan Subedi. Effects of naltrexone on sleep quality and periodic breathing at high altitude. High Alt Med Biol. 00:000-000, 2024. Objective: This study examined the effects of naltrexone on breathing and sleep at high altitude. Mu-opioid receptor (MOR) agonists have a depressive effect on respiration. Naltrexone is known to block the MOR. We hypothesized that MOR blockade with naltrexone would result in higher nocturnal oxygen saturations, fewer apneas, and improved sleep at high altitude. Methods: This double-blind, placebo-controlled, crossover study included nine healthy volunteers (four females, five males) aged 27.9 (4.6) (mean [standard deviation]) years. Two overnight trips spaced at least 2 weeks apart took participants from Loma Linda, CA (355 m) to the Barcroft Laboratory, CA (3,810 m) for each arm. Participants ingested either 50 mg naltrexone or matching placebo at bedtime. Sleep metrics were recorded using an ambulatory physiological sleep monitor (APSM). Subjective data were measured with the Groningen Sleep Quality Scale, Stanford Sleepiness Scale, and the 2018 Lake Louise Score (LLS) for acute mountain sickness (AMS). Results: Mean overnight SpO₂ was lower after taking naltrexone, 81% (6) versus 83% (4) (mean difference 1.9% [2.1, 95% confidence interval or CI = 0.1-3.6, p = 0.040]). The lowest overnight SpO₂ (nadir) was lower on naltrexone 70% (6) versus 74% (4) (dif. 4.6% [4.3], CI = 1.0-8.2, p = 0.020). Total sleep time and total apnea-hypopnea index were unchanged. Subjective sleep quality was significantly worse on naltrexone measured via the Groningen Sleep Quality Scale (p = 0.033) and Stanford Sleepiness Scale (p = 0.038). AMS measured via LLS was significantly worse while taking naltrexone (p = 0.025). Conclusion: Contrary to our hypothesis, this study demonstrated a significant decrease in nocturnal oxygen saturation, worse sleep quality, and AMS scores. Further characterization of the MOR's effects on sleep and AMS is needed to evaluate potential exacerbating mechanisms for AMS and poor sleep quality at altitude.

Luks, Andrew M., Thomas G. DeLoughery, Jeffrey H. Gertsch, and Suzy Stokes. Clinical conundrum: return to high altitude after cerebral venous sinus thrombosis. High Alt Med Biol. 00:00-00, 2024.

Autoimmune myasthenia gravis (MG) is a condition commonly caused by the production of antibodies that block acetylcholine receptors. Until recently, gastrointestinal (GI) symptoms were considered rare in myasthenia gravis, but are now being proposed as an early identification tool. Presented here is a case study that exemplifies GI symptoms in MG, exacerbated by low barometric pressure at altitude. This illustrates the need to identify GI symptoms earlier in MG patients, as well as the need for providers at high altitude to be aware of these manifestations of MG.

Esteban Ortiz-Prado, Juan Sebastian Izquierdo-Condoy, María G. Dávila-Rosero, Jorge Vásconez-González, Ana M. Diaz, Carla E. Moyano, Vanessa Arcos-Valle, Ginés Viscor, and Joshua H. West. Reduced Violence-Related Burden and Mortality at Higher Altitudes: Examining the Association between High Altitude Living and Homicide Rates in Ecuador. High Alt Med Biol. 00:000-000, 0000. Background: Homicides are a major public health concern and a leading cause of preventable deaths worldwide. The relationship between altitude and homicides remains unclear, and evidence of the possible effects of living at high altitudes on homicide rates is limited. This research aimed to investigate the mortality rates resulting from various types of aggression that culminated in homicides in Ecuador and to explore potential differences associated with altitude. Methods: An ecological analysis of homicide rates in Ecuador was conducted from 2001 to 2022. Homicide cases and the population at risk were categorized based on their place of residence according to two altitude classifications: a binary classification of low (<2,500 m) and high altitude (>2,500 m), and a detailed classification according to criteria by the International Society for Mountain Medicine, which includes low (<1,500 m), moderate (1,500-2,500 m), high (2,500-3,500 m), and very high altitude (3,500-5,500 m) categories. Both crude and directly age-sex standardized mortality rates were calculated for each altitude category. Results: We analyzed a total of 40,708 deaths attributed to aggressions (ICD-10 codes X85-Y09). The total homicide rate for men was 21.29 per 100,000 (95% confidence interval [CI]: 9.55-32.37), whereas for women, it was 2.46 per 100,000 (95% CI: 1.44-3.27). Average rates across the 22 analyzed years were higher at low altitudes (men: 13.2/100,000 and women: 1.33/100,000) as compared with high altitudes (men: 5.79/100,000 and women: 1.05/100,000). Notably, the male-to-female rate difference was more pronounced at low altitudes (898%) than at high altitudes (451%). Conclusions: Our study revealed a higher prevalence of homicides in certain provinces and significant disparities in mortality rates between men and women. Although we cannot establish a direct relationship between altitude and homicide rates, further research is needed to explore potential confounding factors and a better understanding of the underlying causes for these variations.

Szymczak, Robert K., Magdalena Sawicka, and Małgorzata Jelitto. Recurrent pulmonary embolism at high altitude in a mountaineer with hereditary thrombophilia. High Alt Med Biol. 00:000-000, 2024.-It is speculated that high-altitude travel is an independent risk factor for thrombosis. Mountaineering-specific factors, such as hypoxia, cold, and immobilization, may interact with patient-specific risk factors and contribute to thrombus formation. We present the case of a mountaineer with hereditary thrombophilia who experienced recurrent pulmonary embolism during high-altitude expeditions.