Transcerebral exchange kinetics of large neutral amino acids during acute inspiratory hypoxia in humans

Preliminary screening of biomarkers in HAPE based on quasi-targeted metabolomics

High altitude pulmonary edema (HAPE) is a serious threat to the physical and mental health of people who quickly enter high plateaus, deserves more attention and in-depth research. In our study, through the detection of various physiological indexes and other phenotypes in a HAPE rat model, the HAPE group showed a significant decrease in oxygen partial pressure and oxygen saturation, and a significant increase in pulmonary artery pressure and lung tissue water content. The lung histomorphology showed characteristics such as pulmonary interstitial thickening and inflammatory cell infiltration. We applied quasi-targeted metabolomics to compare and analyze the components of metabolites in arterial–veinous blood in control rats and HAPE rats. Using kyoto Encyclopedia of Genes Genomes (KEGG) enrichment analysis and two machine algorithms, we speculate that after hypoxic stress and comparing arterial blood and venous blood products in rats, the metabolites were richer, indicating that normal physiological activities, such as metabolism and pulmonary circulationhad a greater impact after hypoxic stress; D-mannoseDOWN, oxidized glutathioneDOWN, glutathione disulfideDOWN, and dehydrocholic acidDOWN in arterial blood play key roles in predicting the occurrence of HAPE; in venous blood, L-leucineDOWN, L-thyroxineDOWN, and cis-4-hydroxy- D-prolineDOWN may have key roles, which can be considered biomarkers of HAPE. This result provides a new perspective for the further diagnosis and treatment of plateau disease and lays a strong foundation for further research.

Development and validation of a metabolite index for obstructive sleep apnea across race/ethnicities

Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent episodes of upper airway obstruction during sleep resulting in oxygen desaturation and sleep fragmentation, and associated with increased risk of adverse health outcomes. Metabolites are being increasingly used for biomarker discovery and evaluation of disease processes and progression. Studying metabolomic associations with OSA in a diverse community-based cohort may provide insights into the pathophysiology of OSA. We aimed to develop and replicate a metabolite index for OSA and identify individual metabolites associated with OSA. We studied 219 metabolites and their associations with the apnea hypopnea index (AHI) and with moderate-severe OSA (AHI ≥ 15) in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) (n = 3507) using two methods: (1) association analysis of individual metabolites, and (2) least absolute shrinkage and selection operator (LASSO) regression to identify a subset of metabolites jointly associated with OSA, which was used to develop a metabolite index for OSA. Results were validated in the Multi-Ethnic Study of Atherosclerosis (MESA) (n = 475). When assessing the associations with individual metabolites, we identified seven metabolites significantly positively associated with OSA in HCHS/SOL (FDR p < 0.05), of which four associations-glutamate, oleoyl-linoleoyl-glycerol (18:1/18:2), linoleoyl-linoleoyl-glycerol (18:2/18:2) and phenylalanine, were replicated in MESA (one sided-p < 0.05). The OSA metabolite index, composed of 14 metabolites, was associated with a 50% increased risk for moderate-severe OSA (OR = 1.50 [95% CI 1.21-1.85] per 1 SD of OSA metabolite index, p < 0.001) in HCHS/SOL and 55% increased risk (OR = 1.55 [95% CI 1.10-2.20] per 1 SD of OSA metabolite index, p = 0.013) in MESA, both adjusted for demographics, lifestyle, and comorbidities. Similar albeit less significant associations were observed for AHI. Replication of the metabolite index in an independent multi-ethnic dataset demonstrates the robustness of metabolomic-based OSA index to population heterogeneity. Replicated metabolite associations may provide insights into OSA-related molecular and metabolic mechanisms.

CHANGE OF INDICES OF THE AMINO ACID COMPOSITION OF RATS’ HEARTS AT ARTIFICIAL HYPOBIOSIS

A series of unsolved questions in such sciences as: medicine, veterinary, biology still exist in the modern world. One of them is a search for new promising ways of anaesthetization, at which it would be unnecessary to use apparatuses as an “artificial heart”, “artificial ventilation of lungs” at short-term surgical interventions. Just artificial hypobiosis may become one of such methods. Main conditions for creation are a synchronous effect of such factors as hypoxia, hypercapnia, hypothermia. That is why for confirming the safety of this method in pre-clinical studies with a further perspective of using at clinical ones, it is necessary to study the mechanism of an effect and influence of the hypobiotic condition on the homeostasis of the living organism in detail. Rats are the best research object in this case. Just they have a similar physiological structure of such organs as a heart. An urgent question about changes that take place in the amino acid composition under the hypobiotic effect still be unexplained. That is why the aim of the study was to investigate amino acid changes of the rat heart under condition of artificial hypobiosis. White outbred male rats with mass 180–200 g were used in the experiments. The animals were divided in groups: control (intact) and experimental: the condition of artificial hypobiosis (first group) and 24 hours after release from artificial hypobiosis (second group). The number of animals in each group n=5. The experiments were conducted according to requirements of “The European convention about protection of vertebral animals, used with experimental or other scientific aims” (Strasbourg, France 1985), by general ethical principles of experiments with animals, approved by the First national congress of Ukraine on bioethics (2001). As a result of the conducted studies, a little decrease of several amino acids under condition of artificial hypobiosis was demonstrated. First of all, a decrease of such amino acids as aminosuccinic, glutamic, isoleucine, leucine, lysine, arginine was observed in rats’ hearths under artificial hypobiosis. There was also demonstrated an increase of the level of these amino acids in rats’ hearts after 24 hours after release from it.