Alterations to cardiac morphology and function among high-altitude workers: a retrospective cohort study

Recent advances in predicting acute mountain sickness: from multidimensional cohort studies to cutting-edge model applications

High-altitude illnesses, encompassing a spectrum of health threats including Acute Mountain Sickness (AMS), pose significant challenges to individuals exposed to high altitude environments, necessitating effective prophylaxis and immediate management. Given the variability in individual responses to these conditions, accurate prediction of high-altitude illnesses onset is of paramount importance. This review systematically consolidates recent advancements in research on predicting AMS by evaluating existing cohort data, predictive models, and methodologies, while also delving into the application of emerging technologies. Through a thorough analysis of scholarly literature, we discuss traditional prediction methods anchored in physiological parameters (e.g., heart rate, respiratory frequency, blood pressure) and biochemical markers, as well as the integration and utility of novel technologies such as biosensors, genetic testing, and artificial intelligence within high-altitude prediction research. While conventional pre-diction techniques have been extensively used, they are often constrained by limitations in accuracy, reliability, and multifactorial influences. The advent of these innovative technologies holds promise for more precise individual risk assessments and personalized preventive and therapeutic strategies across various forms of AMS. Future research endeavors must pivot decisively towards the meticulous identification and stringent validation of innovative predictive biomarkers and models. This strategic re-direction should catalyze intensified interdisciplinary cooperation to significantly deepen our mechanistic insights into the pathogenesis of AMS while refining existing prediction methodologies. These groundbreaking advancements harbor the potential to fundamentally transform preventive and therapeutic frameworks for high-altitude illnesses, ultimately securing augmented safety standards and wellbeing for individuals operating at elevated altitudes with far-reaching global implications.

Healthy worker survival effect at a high-altitude mine: prospective cohort observation

Very little is known about the factors of healthy worker survival effect at high-altitude mines. We conducted this cohort observation of the new hires for a high-altitude gold mine in Kyrgyzstan with the aim to ascertain predictors of survival at work. All new hires in 2009 through 2012 for a high-altitude gold mine (3600–4500 m above sea level) were followed up to January 2022. We tested the association of demographic, physiological predictors and diagnoses at the pre-employment screening with non-survival at work in Cox proportional hazards yielding hazard ratios (HR) with their 95% confidence intervals (CI). The cumulative observation time was 5190 person-years. Blood pressure at pre-employment, lung function, the diagnoses of essential hypertension, chronic obstructive pulmonary disease (COPD) or any other analyzed physiological variables were not associated with non-survival at work. However, smoking (HR 1.55; 95% CI 1.10; 2.17) increased the likelihood of non-survival at work, independent of any diagnosis or lowland residence (HR 1.95; 95% CI 1.31; 2.90). Adjusted for covariates and all diagnoses, having chronic rheumatic fever (HR 10.95; 95% CI 2.92; 33.92), hemorrhoids (HR 1.32; 95% CI 1.01; 3.75), adhesive otitis (HR 1.74; 95% CI 1.05; 2.89) or obesity (HR 1.71; 95% CI 1.01; 2.88) were associated with non-survival at work with time. This prospective observation of new hires for a high-altitude mining operation demonstrated that selected diagnoses, smoking and lowland residence elevated the risk of early exit in prospective workers.

Cardiac Adaptation to Prolonged High Altitude Migration Assessed by Speckle Tracking Echocardiography

Objective

Exposure to high altitudes represents physiological stress that leads to significant changes in cardiovascular properties. However, long-term cardiovascular adaptions to high altitude migration of lowlanders have not been described. Accordingly, we measured changes in cardiovascular properties following prolonged hypoxic exposure in acclimatized Han migrants and Tibetans.

Methods

Echocardiographic features of recently adapted Han migrant (3–12 months, n = 64) and highly adapted Han migrant (5–10 years, n = 71) residence in Tibet (4,300 m) using speckle tracking echocardiography were compared to those of age-matched native Tibetans (n = 75) and Han lowlanders living at 1,400 m (n = 60).

Results

Short-term acclimatized migrants showed increased estimated pulmonary artery systolic pressure (PASP) (32.6 ± 5.1 mmHg vs. 21.1 ± 4.2 mmHg, p < 0.05), enlarged right ventricles (RVs), and decreased fractional area change (FAC) with decreased RV longitudinal strain (−20 ± 2.8% vs. −25.5 ± 3.9%, p < 0.05). While left ventricular ejection fraction (LVEF) was preserved, LV diameter (41.7 ± 3.1 mm vs. 49.7 ± 4.8 mm, p < 0.05) and LV longitudinal strain (−18.8 ± 3.2% vs. −22.9 ± 3.3%, p < 0.05) decreased. Compared with recent migrants, longer-term migrants had recovered RV structure and functions with slightly improved RV and LV longitudinal strain, though still lower than lowlander controls; LV size remained small with increased mass index (68.3 ± 12.7 vs. 59.3 ± 9.6, p < 0.05). In contrast, native Tibetans had slightly increased PASP (26.1 ± 3.4 mmHg vs. 21.1 ± 4.2 mmHg, p < 0.05) with minimally altered cardiac deformation compared to lowlanders.

Conclusion

Right ventricular systolic function is impaired in recent (<1 year) migrants to high altitudes but improved during the long-term dwelling. LV remodeling persists in long-term migrants (>5 years) but without impairment of LV systolic or diastolic function. In contrast, cardiac size, structure, and function of native Tibetans are more similar to those of lowland dwelling Hans.

The Clinical Differences of Patients With Traumatic Brain Injury in Plateau and Plain Areas

Objective

Traumatic brain injury (TBI) is a leading cause of death and disability, which tends to have a worse clinical recovery if it occurs in plateau areas than in plain areas. To explore the underlying cause of this outcome preliminarily, this retrospective study was conducted to compare the clinical differences of patients with TBI in plateau and plain areas.

Methods

In this study, 32 patients with TBI in plateau areas (altitude ≥ 4,000 m) and 32 in plain areas (altitude ≤ 1,000 m) were recruited according to the inclusion and exclusion criteria from June 2020 to December 2021. The collected data and compared parameters include clinical features, head CT presentations and Marshall classifications, hematology profile, lipid profile, coagulation profile, and multiorgan (cardiac, liver, renal) function within 24 h of hospital admission, as well as the treatment method and final outcome.

Results

There were no obvious differences in demographic characteristics, including gender, age, height, and weight, between patients with TBI in plateau and plain areas (all P > 0.05). Compared to patients with TBI in plain areas, the time before hospital admission was longer, heartbeat was slower, systolic blood pressure (SBP) was lower, and hospital stays were longer in patients with TBI in plateau areas (all P < 0.05). More importantly, elevated red blood cells (RBCs) count and hemoglobin (HGB) level, enhanced coagulation function, and higher rates of multiorgan (cardiac, liver, and renal) injury were found in patients with TBI in plateau areas (all P < 0.05).

Conclusion

Patients with TBI in plateau areas presented with altered clinical characteristics, enhanced coagulation function, and aggravated predisposition toward multiorgan (cardiac, liver, and renal) injury, compared to patients with TBI in plain areas. Future prospective studies are needed to further elucidate the influences of high altitude on the disease course of TBI.

Mechanisms and Molecular Targets of Compound Danshen Dropping Pill for Heart Disease Caused by High Altitude Based on Network Pharmacology and Molecular Docking

Compound Danshen dropping pill (CDDP), a famous Chinese medicine formula, has been widely used to treat high-altitude heart disease in China. However, its molecular mechanisms, potential targets, and bioactive ingredients remain elusive. In this study, network pharmacology, molecular docking, and validation experiments were combined to investigate the effective active ingredients and molecular mechanisms of CDDP in the treatment of high-altitude heart disease. Tan IIA may be the main active component of CDDP in the treatment of high-altitude heart disease via HIF-1/PI3K/Akt pathways.

Methamphetamine exacerbates pathophysiology of traumatic brain injury at high altitude. Neuroprotective effects of nanodelivery of a potent antioxidant compound H-290/51

Military personnel are often exposed to high altitude (HA, ca. 4500-5000m) for combat operations associated with neurological dysfunctions. HA is a severe stressful situation and people frequently use methamphetamine (METH) or other psychostimulants to cope stress. Since military personnel are prone to different kinds of traumatic brain injury (TBI), in this review we discuss possible effects of METH on concussive head injury (CHI) at HA based on our own observations. METH exposure at HA exacerbates pathophysiology of CHI as compared to normobaric laboratory environment comparable to sea level. Increased blood-brain barrier (BBB) breakdown, edema formation and reductions in the cerebral blood flow (CBF) following CHI were exacerbated by METH intoxication at HA. Damage to cerebral microvasculature and expression of beta catenin was also exacerbated following CHI in METH treated group at HA. TiO2-nanowired delivery of H-290/51 (150mg/kg, i.p.), a potent chain-breaking antioxidant significantly enhanced CBF and reduced BBB breakdown, edema formation, beta catenin expression and brain pathology in METH exposed rats after CHI at HA. These observations are the first to point out that METH exposure in CHI exacerbated brain pathology at HA and this appears to be related with greater production of oxidative stress induced brain pathology, not reported earlier.