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Goulet N, Marcoux C, Bourgon V, Morin R, Mauger JF, Amaratunga R, Imbeault P. Biological sex-related differences in the postprandial triglyceride response to intermittent hypoxaemia in young adults: a randomized crossover trial. J Physiol 2024. [PMID: 38285004 DOI: 10.1113/jp285430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/10/2024] [Indexed: 01/30/2024] Open
Abstract
Obstructive sleep apnoea is characterized by chronic intermittent hypoxaemia and is independently associated with an increased risk of metabolic comorbidities (e.g. type II diabetes and ischaemic heart disease). These comorbidities could be attributable to hypoxaemia-induced alterations in blood lipid profiles. However, it remains unclear whether intermittent hypoxaemia alters triglyceridaemia differently between biological sexes. Therefore, we used a randomized crossover design to examine whether 6 h of moderate intermittent hypoxaemia (15 hypoxaemic cycles/h, 85% oxyhaemoglobin saturation) alters plasma triglyceride levels differently between men and women after a high-fat meal. Relative to men, women displayed lower levels of total triglycerides, in addition to denser triglyceride-rich lipoprotein triglycerides (TRL-TG; mainly very low-density lipoprotein triglycerides and chylomicron remnant triglycerides) and buoyant TRL-TG (mainly chylomicron triglycerides) during normoxia (ambient air) and intermittent hypoxaemia (sex × time: all P ≤ 0.008). Intermittent hypoxaemia led to higher triglyceride levels (condition: all P ≤ 0.016); however, this effect was observed only in men (sex × condition: all P ≤ 0.002). Compared with normoxia, glucose levels were higher in men and lower in women during intermittent hypoxaemia (sex × condition: P < 0.001). The different postprandial responses between biological sexes occurred despite similar reductions in mean oxyhaemoglobin saturation and similar elevations in insulin levels, non-esterified fatty acid levels and mean heart rate (sex × condition: all P ≥ 0.185). These results support growing evidence showing that intermittent hypoxaemia impacts men and women differently, and they might help to explain biological sex-related discrepancies in the rate of certain comorbidities associated with intermittent hypoxaemia. KEY POINTS: Intermittent hypoxaemia is a key characteristic of obstructive sleep apnoea and alters lipid metabolism in multiple tissues, resulting in increased circulating triglyceride levels, an important risk factor for cardiometabolic diseases. Circulating triglyceride levels are regulated differently between biological sexes, with women typically displaying much lower fasting and postprandial triglyceride levels than men, partly explaining why women of all ages experience lower mortality rates from cardiometabolic diseases. In this study, healthy young men and women consumed a high-fat meal and were then exposed to 6 h of intermittent hypoxaemia or ambient air. We show that postprandial triglyceride levels are significantly lower in women compared with men and that intermittent hypoxaemia leads to higher postprandial triglyceride levels in men only. These results might help us to understand better why women living with obstructive sleep apnoea experience lower rates of cardiometabolic diseases (e.g. type II diabetes and ischaemic heart disease) than men living with obstructive sleep apnoea.
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Affiliation(s)
- Nicholas Goulet
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Caroline Marcoux
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Vincent Bourgon
- Laboratoire du Sommeil, Département de psychoéducation et de psychologie, Université du Québec en Outaouais, Gatineau, QC, Canada
| | - Renée Morin
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Ruwan Amaratunga
- Institut du Savoir Montfort, Montfort Hospital, Ottawa, ON, Canada
| | - Pascal Imbeault
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
- Institut du Savoir Montfort, Montfort Hospital, Ottawa, ON, Canada
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Luo W, Xu Y, Gu X, Zhang J, Wang J, Geng F. Divergence of Liver Lipidomes in Tibetan and Yorkshire Pigs Living at Different Altitudes. Molecules 2023; 28:molecules28072991. [PMID: 37049754 PMCID: PMC10095695 DOI: 10.3390/molecules28072991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
The Tibetan pig is a characteristic breed of the Qinghai-Tibet Plateau with distinct physiological and meat quality attributes. The liver lipid profile can offer an important perspective to explore the uniqueness of Tibetan pigs. A quantitative comparison of liver lipidomes revealed significant differences in the lipid profiles between Tibetan and Yorkshire pigs raised at different altitudes. The abundance of lipids in the livers of pigs raised at a high altitude was higher than that of pigs raised at a lower altitude, whereas the abundance of lipids in the livers of Yorkshire pigs was higher than that of Tibetan pigs raised at the same altitude. Of the 1101 lipids identified, 323 and 193 differentially abundant lipids (DALs) were identified in the pairwise comparisons of Tibetan and Yorkshire pigs raised at different altitudes, respectively. The DALs of Tibetan pigs consisted mainly of 161 triglycerides, along with several acylcarnitines, represented by carnitine C2:0, and significant changes in the abundance of some phospholipids. The DALs of Yorkshire pigs were more complex, with significant increases in the abundance of triglycerides, cholesteryl esters, and free fatty acids, and decreases in the abundance of some phospholipids. This research provides strong theoretical and data support for the high-quality development of the highland livestock industry.
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Affiliation(s)
- Wei Luo
- Meat Processing Key Laboratory of Sichuan Province, School of Food and Biological Engineering, Chengdu University, Chengdu 610106, China
| | - Yisha Xu
- Meat Processing Key Laboratory of Sichuan Province, School of Food and Biological Engineering, Chengdu University, Chengdu 610106, China
| | - Xuedong Gu
- College of Food Science, Tibet Agriculture and Animal Husbandry University, Linzhi 860000, China
| | - Jiamin Zhang
- Meat Processing Key Laboratory of Sichuan Province, School of Food and Biological Engineering, Chengdu University, Chengdu 610106, China
| | - Jinqiu Wang
- Meat Processing Key Laboratory of Sichuan Province, School of Food and Biological Engineering, Chengdu University, Chengdu 610106, China
| | - Fang Geng
- Meat Processing Key Laboratory of Sichuan Province, School of Food and Biological Engineering, Chengdu University, Chengdu 610106, China
- Correspondence:
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Marcoux C, Morin R, Mauger JF, Imbeault P. The Effect of Acute Intermittent and Continuous Hypoxia on Plasma Circulating ßOHB Levels Under Different Feeding Statuses in Humans. Front Physiol 2022; 13:937127. [PMID: 35874514 PMCID: PMC9298782 DOI: 10.3389/fphys.2022.937127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction: Acute hypoxia is known to increase circulating nonesterified fatty acid (NEFA) levels. Adipose tissue lipolysis is a major source of NEFA into circulation and insulin suppresses this process when the tissue is insulin sensitive. NEFA can be esterified to triglycerides and/or completely/partially oxidized, the latter leading to ketogenesis in the liver. To our knowledge, the effect of hypoxia on ketogenesis, more specifically ß-hydroxybutyrate (ßOHB) levels, remains unknown in humans. Therefore, the objective of this study was to determine the effect of acute intermittent and continuous hypoxia on circulating ßOHB levels under different feeding status. Methods: Plasma samples from three different randomized crossover studies were assessed for ßOHB concentrations. In the first study, 14 healthy men (23 ± 3.5 years) were exposed to 6 h of normoxia or intermittent hypoxia (IH-Fed) (15 hypoxic events/hour) following an isocaloric meal. In the second study, 10 healthy men (26 ± 5.6 years) were exposed to 6 h of continuous normobaric hypoxia (CH-Fasted) (FiO2 = 0.12) or normoxia in the fasting state. In the third study (CH-Fed), 9 healthy men (24 ± 4.5 years) were exposed to 6 h of normoxia or CH in a constant prandial state. ßOHB, NEFA and insulin levels were measured during all sessions. Results: In the IH-Fed study, ßOHB and NEFA levels tended to be greater over 6 h of IH (condition × time interaction, ßOHB p = 0.108 and NEFA p = 0.062) compared to normoxia. In the CH-Fasted study, ßOHB and NEFA levels increased over time in both experimental conditions, this effect being greater under CH (condition × time interaction, ßOHB p = 0.070; NEFA p = 0.046). In the CH-Fed study, ßOHB levels slightly increased up to 180 min before falling back to initial concentrations by the end of the protocol in both normoxia and CH (main effect of time, p = 0.062), while NEFA were significantly higher under CH (p = 0.006). Conclusion: Acute normobaric hypoxia exposure tends to increase plasma ßOHB concentrations over time in healthy men. The stimulating effect of hypoxia on plasma ßOHB levels is however attenuated during postprandial and prandial states.
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Affiliation(s)
- Caroline Marcoux
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.,Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON, Canada
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Morin R, Goulet N, Mauger JF, Imbeault P. Physiological Responses to Hypoxia on Triglyceride Levels. Front Physiol 2021; 12:730935. [PMID: 34497541 PMCID: PMC8419320 DOI: 10.3389/fphys.2021.730935] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/03/2021] [Indexed: 11/25/2022] Open
Abstract
Hypoxia is a condition during which the body or specific tissues are deprived of oxygen. This phenomenon can occur in response to exposure to hypoxic environmental conditions such as high-altitude, or because of pathophysiological conditions such as obstructive sleep apnea. Circumstances such as these can restrict supply or increase consumption of oxygen, leading to oxyhemoglobin desaturation and tissue hypoxia. In certain cases, hypoxia may lead to severe health consequences such as an increased risk of developing cardiovascular diseases and type 2 diabetes. A potential explanation for the link between hypoxia and an increased risk of developing cardiovascular diseases lies in the disturbing effect of hypoxia on circulating blood lipids, specifically its capacity to increase plasma triglyceride concentrations. Increased circulating triglyceride levels result from the production of triglyceride-rich lipoproteins, such as very-low-density lipoproteins and chylomicrons, exceeding their clearance rate. Considerable research in murine models reports that hypoxia may have detrimental effects on several aspects of triglyceride metabolism. However, in humans, the mechanisms underlying the disturbing effect of hypoxia on triglyceride levels remain unclear. In this mini-review, we outline the available evidence on the physiological responses to hypoxia and their impact on circulating triglyceride levels. We also discuss mechanisms by which hypoxia affects various organs involved in the metabolism of triglyceride-rich lipoproteins. This information will benefit scientists and clinicians interested in the mechanistic of the regulatory cascade responsible for the response to hypoxia and how this response could lead to a deteriorated lipid profile and an increased risk of developing hypoxia-related health consequences.
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Affiliation(s)
- Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicholas Goulet
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.,Hôpital Montfort, Institut du Savoir Montfort, Ottawa, ON, Canada
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Morin R, Mauger JF, Amaratunga R, Imbeault P. The effect of acute intermittent hypoxia on postprandial triglyceride levels in humans: a randomized crossover trial. J Transl Med 2021; 19:268. [PMID: 34158069 PMCID: PMC8220832 DOI: 10.1186/s12967-021-02933-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/09/2021] [Indexed: 12/18/2022] Open
Abstract
Background Obstructive sleep apnea (OSA), a sleep disorder frequently observed in individuals living with obesity, consists of repeated involuntary breathing obstructions during sleep, leading to intermittent hypoxia (IH). In humans, acute continuous hypoxia slightly increases plasma triglycerides (TG). However, no study yet compared the postprandial TG response of individuals with or without OSA under intermittent hypoxia. Methods Using a randomized crossover design, seven individuals diagnosed with moderate OSA and eight healthy individuals without OSA were given a meal after which they were exposed for 6 h to normoxia or intermittent hypoxia (e.g., 15 hypoxic events per hour). Blood lipid levels were measured hourly during each session. Results Peak postprandial TG concentrations tended to be 22% higher under IH irrespective of group (IH × time interaction, p = 0.068). This trend toward higher total plasma TG was attributable to increased levels of denser TG-rich lipoproteins such as very low-density lipoproteins (VLDL) and chylomicrons (CM) remnants. Irrespective of group, the postprandial TG concentrations in denser TG-rich lipoproteins was 20% higher under IH (IH × time interaction, p = 0.036), although IH had virtually no impact on denser TG-rich lipoprotein concentrations in the OSA group. Conclusion Acute intermittent hypoxia tends to negatively affect postprandial TG levels in healthy individuals, which is attributable to an increase in denser TG-carrying lipoprotein levels such as VLDL and CM remnants. This altered postprandial TG response to acute intermittent hypoxia was not observed in individuals with OSA.
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Affiliation(s)
- Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Ruwan Amaratunga
- Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada. .,Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON, Canada. .,Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees, Ottawa, ON, K1N 6N5, Canada.
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