The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes

Promising Natural Medicines for the Treatment of High-Altitude Illness

Li Li, Lin Lin, Bo Wen, Peng-cheng Zhao, Da-sheng Liu, Guo-ming Pang, Zi-rong Wang, Yong Tan, and Cheng Lu. Promising natural medicines for the treatment of high-altitude illness. High Alt Med Biol. 24:175-185, 2023.-High-altitude illness (HAI) is a dangerous disease characterized by oxidative stress, inflammatory damage and hemodynamic changes in the body that can lead to severe damage to the lungs, heart, and brain. Natural medicines are widely known for their multiple active ingredients and pharmacological effects, which may be important in the treatment of HAI. In this review, we outline the specific types of HAI and the underlying pathological mechanisms and summarize the currently documented natural medicines applied in the treatment of acute mountain sickness and high-altitude cerebral edema, high-altitude pulmonary edema, chronic mountain sickness, and high-altitude pulmonary hypertension. Their sources, types, and medicinal sites are summarized, and their active ingredients, pharmacological effects, related mechanisms, and potential toxicity are discussed. In conclusion, natural medicines, as an acceptable complementary and alternative strategy with fewer side effects and more long-term application, can provide a reference for developing more natural antialtitude sickness medicines in the future and have good application prospects in HAI treatment.

MFN2 deficiency promotes cardiac response to hypobaric hypoxia by reprogramming cardiomyocyte metabolism

AIM

Under hypobaric hypoxia (HH), the heart triggers various defense mechanisms including metabolic remodeling against lack of oxygen. Mitofusin 2 (MFN2), located at the mitochondrial outer membrane, is closely involved in the regulation of mitochondrial fusion and cell metabolism. To date, however, the role of MFN2 in cardiac response to HH has not been explored.

METHODS

Loss- and gain-of-function approaches were used to investigate the role of MFN2 in cardiac response to HH. In vitro, the function of MFN2 in the contraction of primary neonatal rat cardiomyocytes under hypoxia was examined. Non-targeted metabolomics and mitochondrial respiration analyses, as well as functional experiments were performed to explore underlying molecular mechanisms.

RESULTS

Our data demonstrated that, following 4 weeks of HH, cardiac-specific MFN2 knockout (MFN2 cKO) mice exhibited significantly better cardiac function than control mice. Moreover, restoring the expression of MFN2 clearly inhibited the cardiac response to HH in MFN2 cKO mice. Importantly, MFN2 knockout significantly improved cardiac metabolic reprogramming during HH, resulting in reduced capacity for fatty acid oxidation (FAO) and oxidative phosphorylation, and increased glycolysis and ATP production. In vitro data showed that down-regulation of MFN2 promoted cardiomyocyte contractility under hypoxia. Interestingly, increased FAO through palmitate treatment decreased contractility of cardiomyocyte with MFN2 knockdown under hypoxia. Furthermore, treatment with mdivi-1, an inhibitor of mitochondrial fission, disrupted HH-induced metabolic reprogramming and subsequently promoted cardiac dysfunction in MFN2-knockout hearts.

CONCLUSION

Our findings provide the first evidence that down-regulation of MFN2 preserves cardiac function in chronic HH by promoting cardiac metabolic reprogramming.

High Altitude Pulmonary Edema, High Altitude Cerebral Edema, and Acute Mountain Sickness: an enhanced opinion from the High Andes - La Paz, Bolivia 3,500 m

Traveling to high altitudes for entertainment or work is sometimes associated with acute high altitude pathologies. In the past, scientific literature from the lowlander point of view was primarily based on mountain climbing. Sea level scientists developed all guidelines, but they need modifications for medical care in high altitude cities. Acute Mountain Sickness, High Altitude Pulmonary Edema, and High Altitude Cerebral Edema are medical conditions that some travelers can face. We present how to diagnose and treat acute high altitude pathologies, based on 51 years of high altitude physiology research and medical practice in hypobaric hypoxic diseases in La Paz, Bolivia (3,600 m; 11,811 ft), at the High Altitude Pulmonary and Pathology Institute (HAPPI - IPPA). These can occasionally present after flights to high altitude cities, both in lowlanders or high-altitude residents during re-entry. Acute high altitude ascent diseases can be adequately diagnosed and treated in high altitude cities following the presented guidelines. Treating these high-altitude illnesses, we had no loss of life. Traveling to a high altitude with sound medical advice should not be feared as it has many benefits. Nowadays, altitude descent and evacuation are not mandatory in populated highland cities, with adequate medical resources.

Impact of High-Flow Nasal Cannula Use in Subjects With COVID-19 ARDS at High Altitudes: Clinical Presentation and Prognostic Factors

BACKGROUND

High-flow nasal cannula (HFNC) reduces the need for intubation in adult subject with acute respiratory failure. Changes in hypobaric hypoxemia have not been studied for subject with an HFNC in ICUs at altitudes > 2,600 m above sea level. In this study, we investigated the efficacy of HFNC treatment in subjects with COVID-19 at high altitudes. We hypothesized that progressive hypoxemia and the increase in breathing frequency associated with COVID-19 in high altitudes affect the success of HFNC therapy and may also influence the performance of the traditionally used predictors of success and failure.

METHODS

This was a prospective cohort study of subjects >18 y with a confirmed diagnosis of COVID-19-induced ARDS requiring HFNC who were admitted to the ICU. Subjects were followed up during the 28 d of HFNC treatment or until failure.

RESULTS

One hundred and eight subjects were enrolled. At admission to the ICU, FIO2 delivery between 0.5-0.8 (odds ratio 0.38 [95% CI 0.17-0.84]) was associated with a better response to HFNC therapy than oxygen delivery on admission between 0.8-1.0 (odds ratio 3.58 [95% CI 1.56-8.22]). This relationship continued during follow-ups at 2, 6, 12, and 24 h, with a progressive increase in the risk of failure (odds ratio 24 h 13.99 [95% CI 4.32-45.26]). A new cutoff for the ratio of oxygen saturation (ROX) index (ROX ≥ 4.88) after 24 h of HFNC administration was demonstrated to be the best predictor of success (odds ratio 11.0 [95% CI 3.3-47.0]).

CONCLUSIONS

High-altitude subjects treated with HFNC for COVID-19 showed a high risk of respiratory failure and progressive hypoxemia when FIO2 requirements were > 0.8 after 24 h of treatment. In these subjects, personalized management should include continuous monitoring of individual clinical conditions (such as oxygenation indices, with cutoffs adapted to those corresponding to high-altitude cities).

Morphological and functional findings in COVID-19 lung disease as compared to Pneumonia, ARDS, and High-Altitude Pulmonary Edema

Coronavirus disease-2019 (COVID-19) may severely affect respiratory function and evolve to life-threatening hypoxia. The clinical experience led to the implementation of standardized protocols assuming similarity to severe acute respiratory syndrome (SARS-CoV-2). Understanding the histopathological and functional patterns is essential to better understand the pathophysiology of COVID-19 and then develop new therapeutic strategies. Epithelial and endothelial cell damage can result from the virus attack, thus leading to immune-mediated response. Pulmonary histopathological findings show the presence of Mallory bodies, alveolar coating cells with nuclear atypia, reactive pneumocytes, reparative fibrosis, intra-alveolar hemorrhage, moderate inflammatory infiltrates, micro-abscesses, microthrombus, hyaline membrane fragments, and emphysema-like lung areas. COVID-19 patients may present different respiratory stages from silent to critical hypoxemia, are associated with the degree of pulmonary parenchymal involvement, thus yielding alteration of ventilation and perfusion relationships. This review aims to: discuss the morphological (histopathological and radiological) and functional findings of COVID-19 compared to acute interstitial pneumonia, acute respiratory distress syndrome (ARDS), and high-altitude pulmonary edema (HAPE), four entities that share common clinical traits, but have peculiar pathophysiological features with potential implications to their clinical management.

Predictive Value of High Preoperative Serum Total Protein and Elevated Hematocrit in Patients with Non-Small-Cell Lung Cancer after Radical Resection

BACKGROUND

The relationship between the dynamic alterations of nutritional indexes before and after surgery, and the prognosis of non-small-cell lung cancer (NSCLC) after radical surgery are unclear. Methods: This study enrolled 100 NSCLC patients in stages I-III who received radical surgery. The preoperative and postoperative 6-month levels of nine nutrition-related indicators were assessed in patients. Survival was analyzed using Kaplan-Meier curves as well as Cox regression models.

RESULTS

Patients had better disease-free survival (DFS) with baseline total protein (TP) >76.66 g/L (75% vs. 50%, P = .027), baseline albumin (ALB) >37.7 g/L (60% vs. 26.7%, P = .002), baseline albumin to globulin ratio (AGR) >1.31 (63.5% vs. 40.5%, P = .006), or baseline globulin (GLOB) <31.42 g/L (39.4% vs. 62.7%, P = .037). Moreover, patients with increased hematocrit (HCT) (69.8% vs. 43.9% P = .013) and mean corpuscular volume (MCV) (73.2% vs. 42.4%, P = .014) at the postoperative 6-month examination had superior DFS. Cox proportional hazards regression analyses demonstrated that age >65 years, adenocarcinoma (pathological type), higher baseline TP, and post-surgery elevated HCT independently predicted favorable DFS.

CONCLUSION

Lower baseline TP and decreased postoperative HCT levels are independent predictors of prognosis in NSCLC following radical surgical procedures.

Ayurvedic management through telemedicine of covid hypoxia non-dependent of oxygen support in a patient with chest CT score of 18/25- A case report

This paper is the first known documentation of a covid patient in ARDS and MODS who recovered from home through Ayurveda telemedicine and when not completely dependent on oxygen. The covid patient suffered from fever, body ache, breathlessness, fatigue, and was admitted to the hospital when his SpO2 was at 56, his CT scores at 18/25, Corads 6 and his NL ratio was at 9. The patient was shifted to another hospital as he refused treatment in the first hospital; in the second hospital also he refused treatment and got himself discharged against medical advice when his SpO2 was at 65, RR 40. The patient sought Ayurvedic treatment through phone voluntarily when in MODS. He showed clinical improvement within a day and the SpO2 steadily raised to reach 94 in 27 days. He may have required invasive mechanical ventilation for COVID-19 ARDS reflected by his raised covid biomarkers (Malik et al., 2021) [1]. But this was not necessitated; also other risk factors for poor outcomes were his old age, comorbidities as diabetes, kidney injury and liver injury. This paper records that oral and ophthalmic administration of Ayurveda medicines can immediately increase SpO2 levels. This case study also opens up possibilities of emergency care in Ayurveda with respect to hypoxia.