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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] [What about the content of this article? (0)] [Affiliation(s)] [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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El Amine Z, Mauger JF, Imbeault P. Human Preadipocytes Differentiated under Hypoxia following PCB126 Exposure during Proliferation: Effects on Differentiation, Glucose Uptake and Adipokine Profile. Cells 2023; 12:2326. [PMID: 37759548 PMCID: PMC10527447 DOI: 10.3390/cells12182326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Persistent organic pollutants (POPs) accumulation and hypoxia are two factors proposed to adversely alter adipose tissue (AT) functions in the context of excess adiposity. Studies have shown that preadipocytes exposure to dioxin and dioxin-like POPs have the greatest deleterious impact on rodent and immortalized human preadipocyte differentiation, but evidence on human preadipocytes is lacking. Additionally, hypoxia is known to strongly interfere with the dioxin-response pathway. Therefore, we tested the effects of pre-differentiation polychlorinated biphenyl (PCB)126 exposure at 10 µM for 3 days and subsequent differentiation under hypoxia on human subcutaneous adipocytes (hSA) differentiation, glucose uptake and expression of selected metabolism- and inflammation-related genes. Pre-differentiation PCB126 exposure lowered the adenosine triphosphate (ATP) content, glucose uptake and leptin expression of mature adipocytes but had limited effects on differentiation under normoxia (21% O2). Under hypoxia (3% O2), preadipocytes ability to differentiate was significantly reduced as reflected by significant decreased lipid accumulation and downregulation of key adipocyte genes such as peroxisome proliferator-activated receptor gamma (PPARγ) and adiponectin. Hypoxia increased glucose uptake and glucose transporter 1 (GLUT1) expression but abolished the adipocytes insulin response and GLUT4 expression. The expression of pro-inflammatory adipokine interleukin-6 (IL-6) was slightly increased by both PCB126 and hypoxia, while IL-8 expression was significantly increased only following the PCB126-hypoxia sequence. These observations suggest that PCB126 does not affect human preadipocyte differentiation, but does affect the subsequent adipocytes population, as reflected by lower ATP levels and absolute glucose uptake. On the other hand, PCB126 and hypoxia exert additive effects on AT inflammation, an important player in the development of chronic diseases such as type 2 diabetes and cardiovascular diseases.
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Affiliation(s)
- Zeinab El Amine
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
- Institut du savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada
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Goulet N, Tetzlaff EJ, Morin R, Mauger J, Amaratunga R, Kenny GP, Imbeault P. No impact of a high-fat meal coupled with intermittent hypoxemia on acute kidney injury biomarkers in adults with and without obstructive sleep apnea. Physiol Rep 2023; 11:e15804. [PMID: 37653582 PMCID: PMC10471792 DOI: 10.14814/phy2.15804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/04/2023] [Accepted: 08/16/2023] [Indexed: 09/02/2023] Open
Abstract
Obstructive sleep apnea (OSA) is characterized by chronic intermittent hypoxemia, which is associated with progressive loss of kidney function, where postprandial fluctuations in renal physiology may further compromise oxygen supply and kidney function. Therefore, we measured biomarkers of acute kidney injury (AKI) following a high-fat meal with and without intermittent hypoxemia. Eighteen healthy young men (mean age [SD]: 22.7 years [3.1]) and seven middle-aged to older individuals with OSA (54.4 years [6.4]) consumed a high-fat meal during normoxia or intermittent hypoxemia (~15 hypoxic cycles per hour, ~85% oxyhemoglobin saturation) for 6 h. We observed no changes in estimated glomerular filtration rate and plasma concentrations of creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) at any measured time points. In both groups, plasma concentrations of interleukin-18 (IL-18) increased after 6 h during normoxia only (p = 0.033, ηp 2 = 0.122), and plasma concentrations of liver-type fatty acid-binding protein (L-FABP) transiently decreased after 3 h in both conditions (p = 0.008, ηp 2 = 0.152). These findings indicate that AKI biomarkers are not acutely elevated during the postprandial state with or without intermittent hypoxemia, suggesting that other mechanisms may play more important roles in the progression of kidney disease in OSA.
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Affiliation(s)
- Nicholas Goulet
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
| | - Emily J. Tetzlaff
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
| | - Renée Morin
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
| | - Jean‐François Mauger
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
| | | | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
| | - Pascal Imbeault
- Behavioural and Metabolic Research Unit, School of Human Kinetics, Faculty of Health SciencesUniversity of OttawaOttawaOntarioCanada
- Institut du Savoir MontfortMontfort HospitalOttawaOntarioCanada
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Amine ZE, Mauger JF, Imbeault P. CYP1A1, VEGFA and Adipokine Responses of Human Adipocytes Co-exposed to PCB126 and Hypoxia. Cells 2022; 11:cells11152282. [PMID: 35892579 PMCID: PMC9331964 DOI: 10.3390/cells11152282] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022] Open
Abstract
It is increasingly recognized that hypoxia may develop in adipose tissue as its mass expands. Adipose tissue is also the main reservoir of lipophilic pollutants, including polychlorinated biphenyls (PCBs). Both hypoxia and PCBs have been shown to alter adipose tissue functions. The signaling pathways induced by hypoxia and pollutants may crosstalk, as they share a common transcription factor: aryl hydrocarbon receptor nuclear translocator (ARNT). Whether hypoxia and PCBs crosstalk and affect adipokine secretion in human adipocytes remains to be explored. Using primary human adipocytes acutely co-exposed to different levels of hypoxia (24 h) and PCB126 (48 h), we observed that hypoxia significantly inhibits the PCB126 induction of cytochrome P450 (CYP1A1) transcription in a dose-response manner, and that Acriflavine (ACF)—an HIF1α inhibitor—partially restores the PCB126 induction of CYP1A1 under hypoxia. On the other hand, exposure to PCB126 did not affect the transcription of the vascular endothelial growth factor-A (VEGFA) under hypoxia. Exposure to hypoxia increased leptin and interleukin-6 (IL-6), and decreased adiponectin levels dose-dependently, while PCB126 increased IL-6 and IL-8 secretion in a dose-dependent manner. Co-exposure to PCB126 and hypoxia did not alter the adipokine secretion pattern observed under hypoxia and PCB126 exposure alone. In conclusion, our results indicate that (1) hypoxia inhibits PCB126-induced CYP1A1 expression at least partly through ARNT-dependent means, suggesting that hypoxia could affect PCB metabolism and toxicity in adipose tissue, and (2) hypoxia and PCB126 affect leptin, adiponectin, IL-6 and IL-8 secretion differently, with no apparent crosstalk between the two factors.
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Affiliation(s)
- Zeinab El Amine
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
- Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada
- Correspondence: ; Tel.: +1-(613)-562-5800-(7290)
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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: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Mahat B, Chassé É, Mauger JF, Imbeault P. Correction to: Effects of acute hypoxia on human adipose tissue lipoprotein lipase activity and lipolysis. J Transl Med 2021; 19:136. [PMID: 33794914 PMCID: PMC8017645 DOI: 10.1186/s12967-021-02758-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Bimit Mahat
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health, Sciences, University of Ottawa, 125, University Street (room 350), Ottawa, ON, K1N 6N5, Canada
| | - Étienne Chassé
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health, Sciences, University of Ottawa, 125, University Street (room 350), Ottawa, ON, K1N 6N5, Canada
| | - Jean-François Mauger
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health, Sciences, University of Ottawa, 125, University Street (room 350), Ottawa, ON, K1N 6N5, Canada
| | - Pascal Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health, Sciences, University of Ottawa, 125, University Street (room 350), Ottawa, ON, K1N 6N5, Canada.
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Abstract
Adipose tissue expansion has been suggested to impair oxygen (O2) diffusion in the adipose tissue and cause hypoxia. This study aimed at characterising the effects of hypoxia on adipocyte lipid storage and mobilisation functions. Human preadipocytes were exposed to different O2 tensions (3, 10 and 21%) either acutely for 24 h after differentiation (acute exposure) or during differentiation (14d, chronic hypoxia). Lipoprotein lipase (LPL) activity was decreased dose-dependently by both acute and chronic hypoxia (p < .05). Acute exposure to 3, and 10% O2 stimulated the expression of lipid storage gene, while chronic exposure to 3% O2 inhibited the expression of genes involved in lipid storage and mobilisation (p < .05). Acute hypoxia dose-dependently stimulated basal lipolysis. Conversely, chronic hypoxia did not affect basal lipolysis but significantly decreased isoproterenol-stimulated lipolysis (p < .05). In conclusion, the effects of hypoxia on human adipocyte lipid storage and mobilisation functions are complex but could favour ectopic fat deposition.
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Affiliation(s)
- Bimit Mahat
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Jean-François Mauger
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Pascal Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
- Institut du savoir Montfort, Hôpital Montfort, Ottawa, Canada
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Beharriell TH, Mavor MP, Ramos W, Mauger JF, Imbeault P, Graham RB. Beyond the mechanical lens: Systemic inflammatory responses to repetitive lifting under varying loads and frequencies. Appl Ergon 2020; 89:103199. [PMID: 32854825 DOI: 10.1016/j.apergo.2020.103199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE Currently, low back disorder (LBD) research focuses primarily on mechanical variables to assess whether task demands exceed tissue capacity; however, it is important to assess how other nonmechanical variables affect tissue capacity in a time-dependent manner. The current investigation sought to explore physiological responses to an acute lifting task, as lifting has been implicated as a risk factor in the development of LBDs. METHODS Twelve participants completed two sessions of 2 h of repetitive symmetrical lifting from floor to knuckle height under two conditions, matched for total external work (Low Force High Repetition (LFHR) and High Force Low Repetition (HFLR)). Full-body kinematics and ground reaction forces were measured throughout. Interleukin 6 (IL-6) and interleukin 8 (IL-8), markers of systemic inflammation, were assessed from blood sampling at Baseline, 0, 4 and 24 h post-lifting on both days. Dual x-ray absorptiometry (DEXA) scans were also performed on participants to quantify body composition. RESULTS Significant load (HFLR and LFHR) * time (Baseline, 0, 4, 24 h) interaction effects were found for both IL-6 and IL-8, where the LFHR condition resulted in greater responses at 0 and 4 h post-lifting. CONCLUSIONS This was the first study of its kind to concurrently measure peak and cumulative spinal moments and their relationship to systemic inflammation in both sexes, while strictly controlling for confounding variables (e.g. physical activity, caloric intake, body composition, etc.). Greater levels of IL-6 and IL-8 were seen in the LFHR condition, likely due to the greater cumulative spinal moments in this condition.
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Affiliation(s)
- Tianna H Beharriell
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada
| | - Matthew P Mavor
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada
| | - Wantuir Ramos
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada
| | - Ryan B Graham
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 200 Lees Avenue, Ottawa, Ontario, K1N 6N5, Canada.
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11
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Pepin A, Imbeault P. [The controversial effects of low-calorie sweeteners]. Med Sci (Paris) 2020; 36:472-478. [PMID: 32452369 DOI: 10.1051/medsci/2020079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Substantial reviews of the most recent evidence report a strong relationship between the consumption of sugar-sweetened beverages and adverse health effects, such as the prevalence of obesity and metabolic diseases. Various public policies were recently undertaken by many countries in the hope of reducing sugar-sweetened beverage consumption amongst their population. This has led the food industries to promote low-calorie sweeteners (sugar substitutes) as a healthy alternative that would limit caloric intake without compromising the sweet taste of food and beverages. However, is the use of low-calorie sweeteners as a means of limiting or reducing energy intake without consequences for our health? This review aims to discuss the effects of low-calorie sweeteners consumption on health and to elucidate whether their use should be recommended by health professionals to their patients as part of weight management.
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Affiliation(s)
- Alexandra Pepin
- Unité de recherche sur le comportement et le métabolisme, École des Sciences de l'Activité Physique, Faculté des Sciences de la Santé, Université d'Ottawa, 125 rue Université, K1N 6N5 Ottawa, Ontario, Canada
| | - Pascal Imbeault
- Unité de recherche sur le comportement et le métabolisme, École des Sciences de l'Activité Physique, Faculté des Sciences de la Santé, Université d'Ottawa, 125 rue Université, K1N 6N5 Ottawa, Ontario, Canada
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Ravanelli N, Imbeault P, Jay O. Steady‐state sweating during exercise is determined by the evaporative requirement for heat balance independently of absolute core and skin temperatures. J Physiol 2020; 598:2607-2619. [DOI: 10.1113/jp279447] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 04/01/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Nicholas Ravanelli
- Cardiovascular Prevention and Rehabilitation CentreUniversité de MontréalMontréal Heart Institute Research Centre Montréal Canada
| | - Pascal Imbeault
- School of Human KineticsFaculty of Health SciencesUniversity of Ottawa 200 Lees Ave Ottawa Canada
| | - Ollie Jay
- The University of Sydney, Thermal Ergonomics Laboratory, Sydney School of Health SciencesFaculty of Medicine and Health Sydney NSW Australia
- The University of SydneyCharles Perkins Centre Camperdown NSW Australia
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Coombs GB, Cramer MN, Ravanelli N, Imbeault P, Jay O. Normobaric hypoxia does not alter the critical environmental limits for thermal balance during exercise‐heat stress. Exp Physiol 2020; 106:359-369. [DOI: 10.1113/ep088466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/18/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Geoff B. Coombs
- School of Human Kinetics, Faculty of Health Sciences University of Ottawa ON Canada
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences University of British Columbia (Okanagan) Kelowna BC Canada
| | - Matthew N. Cramer
- School of Human Kinetics, Faculty of Health Sciences University of Ottawa ON Canada
- Defence Research and Development Canada Toronto Research Centre Toronto ON Canada
| | - Nicholas Ravanelli
- Cardiovascular Prevention and Rehabilitation Centre and Research Centre Montreal Heart Institute Montreal QC Canada
- Département de pharmacologie et physiologie Université de Montréal Montreal QC Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences University of Ottawa ON Canada
| | - Ollie Jay
- School of Human Kinetics, Faculty of Health Sciences University of Ottawa ON Canada
- University of Sydney, Faculty of Medicine and Health Thermal Ergonomics Laboratory Sydney NSW Australia
- University of Sydney Charles Perkins Centre Sydney NSW Australia
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Ravanelli N, Gagnon D, Imbeault P, Jay O. A retrospective analysis to determine if exercise training-induced thermoregulatory adaptations are mediated by increased fitness or heat acclimation. Exp Physiol 2020; 106:282-289. [PMID: 32118324 DOI: 10.1113/ep088385] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/28/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Are fitness-related improvements in thermoregulatory responses during uncompensable heat stress mediated by aerobic capacity V ̇ O 2 max or is it the partial heat acclimation associated with training? What is the main finding and its importance? During uncompensable heat stress, individuals with high and low V ̇ O 2 max displayed similar sweating and core temperature responses whereas exercise training in previously untrained individuals resulted in a greater sweat rate and a smaller rise in core temperature. These observations suggest that it is training, not V ̇ O 2 max per se, that mediates thermoregulatory improvements during uncompensable heat stress. ABSTRACT It remains unclear whether aerobic fitness, as defined by the maximum rate of oxygen consumption V ̇ O 2 max , independently improves heat dissipation in uncompensable environments, or whether the thermoregulatory adaptations associated with heat acclimation are due to repeated bouts of exercise-induced heat stress during regular aerobic training. The present analysis sought to determine if V ̇ O 2 max independently influences thermoregulatory sweating, maximum skin wettedness (ωmax ) and the change in rectal temperature (ΔTre ) during 60 min of exercise in an uncompensable environment (37.0 ± 0.8°C, 4.0 ± 0.2 kPa, 64 ± 3% relative humidity) at a fixed rate of heat production per unit mass (6 W kg-1 ). Retrospective analyses were performed on 22 participants (3 groups), aerobically unfit (UF; n = 7; V ̇ O 2 max : 41.7 ± 9.4 ml kg-1 min-1 ), aerobically fit (F; n = 7; V ̇ O 2 max : 55.6 ± 4.3 ml kg-1 min-1 ; P < 0.01) and aerobically unfit (n = 8) individuals, before (pre; V ̇ O 2 max : 45.8 ± 11.6 ml kg-1 min-1 ) and after (post; V ̇ O 2 max : 52.0 ± 11.1 ml kg-1 min-1 ; P < 0.001) an 8-week training intervention. ωmax was similar between UF (0.74 ± 0.09) and F (0.78 ± 0.08, P = 0.22). However, ωmax was greater post- (0.84 ± 0.08) compared to pre- (0.72 ± 0.06, P = 0.02) training. During exercise, mean local sweat rate (forearm and upper-back) was greater post- (1.24 ± 0.20 mg cm-2 min-1 ) compared to pre- (1.04 ± 0.25 mg cm-2 min-1 , P < 0.01) training, but similar between UF (0.94 ± 0.31 mg cm-2 min-1 , P = 0.90) and F (1.02 ± 0.30 mg cm-2 min-1 ). The ΔTre at 60 min of exercise was greater pre- (1.13 ± 0.16°C, P < 0.01) compared to post- (0.96 ± 0.14°C) training, but similar between UF (0.85 ± 0.29°C, P = 0.22) and F (0.95 ± 0.22°C). Taken together, aerobic training, not V ̇ O 2 max per se, confers an increased ωmax , greater sweat rate, and smaller rise in core temperature during uncompensable heat stress in fit individuals.
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Affiliation(s)
- Nicholas Ravanelli
- Cardiovascular Prevention and Rehabilitation Centre and Research Centre, Montreal Heart Institute, Montreal, QC, Canada.,Département de pharmacologie et physiologie, Université de Montréal, Montreal, QC, Canada
| | - Daniel Gagnon
- Cardiovascular Prevention and Rehabilitation Centre and Research Centre, Montreal Heart Institute, Montreal, QC, Canada.,Département de pharmacologie et physiologie, Université de Montréal, Montreal, QC, Canada
| | - Pascal Imbeault
- School of Human Kinetics, University of Ottawa, 200 Lees Ave, Ottawa, Canada
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia.,Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
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Ravanelli N, Coombs G, Imbeault P, Jay O. Thermoregulatory adaptations with progressive heat acclimation are predominantly evident in uncompensable, but not compensable, conditions. J Appl Physiol (1985) 2019; 127:1095-1106. [PMID: 31414952 DOI: 10.1152/japplphysiol.00220.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study assessed whether, notwithstanding lower resting absolute core temperatures, alterations in time-dependent changes in thermoregulatory responses following partial and complete heat acclimation (HA) are only evident during uncompensable heat stress. Eight untrained individuals underwent 8 wk of aerobic training (i.e., partial HA) followed by 6 days of HA in 38°C/65% relative humidity (RH) (i.e., complete HA). On separate days, esophageal temperature (Tes), arm (LSRarm), and back (LSRback) sweat rate, and whole body sweat rate (WBSR) were measured during a 45-min compensable (37°C/30% RH) and 60-min uncompensable (37°C/60% RH) heat stress trial pre-training (PRE-TRN), post-training (POST-TRN), and post-heat acclimation (POST-HA). For compensable heat stress trials, resting Tes was lower POST-TRN (36.74 ± 0.27°C, P = 0.05) and POST-HA (36.60 ± 0.27°C, P = 0.001) compared with PRE-TRN (36.99 ± 0.19°C); however, ΔTes was similar in all trials (PRE-TRN:0.40 ± 0.23°C; POST-TRN:0.42 ± 0.20°C; POST-HA:0.43 ± 0.12°C, P = 0.97). While LSRback was unaltered by HA (P = 0.94), end-exercise LSRarm was higher POST-TRN (0.70 ± 0.14 mg·cm-2·min-1, P < 0.001) and POST-HA (0.75 ± 0.16 mg·cm-2·min-1, P < 0.001) compared with PRE-TRN (0.61 ± 0.15 mg·cm-2·min-1). Despite matched evaporative heat balance requirements, steady-state WBSR (31st-45th min) was greater POST-TRN (12.7 ± 1.0 g/min, P = 0.02) and POST-HA (12.9 ± 0.8 g/min, P = 0.004), compared with PRE-TRN (11.7 ± 0.9 g/min). For uncompensable heat stress trials, resting Tes was lower POST-TRN (36.77 ± 0.22°C, P = 0.05) and POST-HA (36.62 ± 0.15°C, P = 0.03) compared with PRE-TRN (36.86 ± 0.24°C). But ΔTes was smaller POST-TRN (0.77 ± 0.19°C, P = 0.05) and POST-HA (0.75 ± 0.15°C, P = 0.04) compared with PRE-TRN (1.10 ± 0.32°C). LSRback and LSRarm increased with HA (P < 0.007), supporting the greater WBSR with HA (POST-TRN:14.4 ± 2.4 g/min, P < 0.001; POST-HA:16.8 ± 2.8 g/min, P < 0.001) compared with PRE-TRN (12.7 ± 3.2 g/min). In conclusion, the thermal benefits of HA are primarily evident when conditions challenge the physiological capacity to dissipate heat.NEW & NOTEWORTHY We demonstrate that neither partial nor complete heat acclimation alters the change in core temperature during compensable heat stress compared with an unacclimated state, despite a marginally greater whole body sweat rate. However, the greater local and whole body sweat rate with partial and complete heat acclimation reduced the rise in core temperature during 60 min of uncompensable heat stress compared with an unacclimated state, suggesting the improvements in heat dissipation associated with heat acclimation are best observed when the upper physiological limits for evaporative heat loss are challenged.
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Affiliation(s)
- Nicholas Ravanelli
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada.,Département de Pharmacologie et Physiologie, Cardiovascular Prevention and Rehabilitation Centre, Montreal Heart Institute Research Centre, Université de Montréal, Montreal, Quebec, Canada.,Thermal Ergonomics Laboratory, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Geoff Coombs
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada.,Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Pascal Imbeault
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
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Mauger JF, Chassé É, Mahat B, Lindon C, Bordenave N, Imbeault P. The Effect of Acute Continuous Hypoxia on Triglyceride Levels in Constantly Fed Healthy Men. Front Physiol 2019; 10:752. [PMID: 31275165 PMCID: PMC6591477 DOI: 10.3389/fphys.2019.00752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/31/2019] [Indexed: 02/01/2023] Open
Abstract
Introduction Elevated plasma triglyceride (TG) concentrations are an important contributor to deleterious metabolic alterations. Evidence in animals suggest that acute exposure to an environment with reduced oxygen inhibits plasma TG clearance and causes important rise in plasma TG, especially in the postprandial state. The objective of this study was to characterize the effects of an acute exposure to normobaric hypoxia on prandial TG levels in 2 distinct lipoprotein subtypes in healthy humans: chylomicrons which are secreted by the intestine and carry dietary lipids, and denser TG carriers (mainly VLDL), which are secreted by the liver and carry endogenous lipids. Plasma lipolytic activity was also assessed. It was hypothesized that hypoxia would reduce prandial plasma lipolytic activity and raise prandial TG levels in both lipoprotein subtypes. Methods Using a randomized crossover design, 9 healthy young men were studied for 6 h in a constantly fed state while being exposed to either normobaric hypoxia (FiO2 = 0.12) and normoxic conditions on two different days. Prandial glucose, TG, non-esterified fatty acid (NEFA), and post-heparin plasma lipolytic activity were measured during each session. Results Six hours of exposure to hypoxia marginally increase prandial glycemia (+5%, p = 0.06) while increasing insulinemia by 40% (p = 0.04). Hypoxia induced a 30% rise in prandial NEFA levels and tended to slightly increased total prandial TG levels by 15% (p = 0.11). No difference was observed in TG concentrations and metabolism of chylomicrons between conditions. However, TG in the VLDL containing fraction decreased significantly overtime under normoxia but not under hypoxia (time × condition interaction, p = 0.02). No difference was observed in post-heparin plasmatic lipolytic activity between conditions. Conclusion Acute hypoxia in healthy men tends to increase prandial VLDL-TG levels. These results lend support to the increased blood lipid levels reported in animals exposed acutely to lower partial pressures of oxygen.
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Affiliation(s)
- Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Étienne Chassé
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Bimit Mahat
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Clare Lindon
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicolas Bordenave
- School of Nutrition Sciences, 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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Ravanelli N, Imbeault P, Jay O. Circadian Rhythm Does Not Alter the Sweating Response to Exercise in Thermoneutral and Warm Ambient Temperatures. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.590.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Ollie Jay
- University of SydneyLidcombeAustralia
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Affiliation(s)
- Ollie Jay
- Faculty of Health SciencesUniversity of SydneySydneyAustralia
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Mahat B, Chassé É, Lindon C, Mauger JF, Imbeault P. No effect of acute normobaric hypoxia on plasma triglyceride levels in fasting healthy men. Appl Physiol Nutr Metab 2018; 43:727-732. [PMID: 29466682 DOI: 10.1139/apnm-2017-0505] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Circulating fatty acids are a major systemic energy source in the fasting state as well as a determinant of hepatic triglycerides (TG)-rich very-low-density lipoprotein production. Upon acute hypoxia, sympathetic arousal induces adipose tissue lipolysis, resulting in an increase in circulating nonesterified fatty acids (NEFA). Animal studies suggest that TG clearance may also be strongly reduced under hypoxia, though this effect has been shown to be dependent on temperature. Whether the hypoxia-induced rise in blood fatty acid concentrations affects fasting TG levels in humans under thermoneutral conditions remains unknown. TG, NEFA, and glycerol levels were measured in fasted healthy young men (n = 10) exposed for 6 h to either normoxia (ambient air) or acute hypoxia (fraction of inspired oxygen = 0.12) in a randomized, crossover design. Participants were casually clothed and rested in front of a fan in an environmental chamber maintained at 28 °C during each trial. Under hypoxia, a significantly greater increase in NEFA occurred (condition × time interaction, p = 0.049) and glycerol levels tended to be higher (condition × time, p = 0.104), suggesting an increase in adipose tissue lipolysis. However, plasma TG levels did not change over time and did not differ between the normoxia and hypoxia conditions. In conclusion, acute exposure to normobaric hypoxia under thermoneutral condition in healthy men during fasting state increased lipolysis without affecting circulating TG.
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Affiliation(s)
- Bimit Mahat
- a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Étienne Chassé
- a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Clare Lindon
- a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Jean-François Mauger
- a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Pascal Imbeault
- a Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,b Institut du savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada
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Imbeault P, Ravanelli N, Chevrier J. Can POPs be substantially popped out through sweat? Environ Int 2018; 111:131-132. [PMID: 29197670 DOI: 10.1016/j.envint.2017.11.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/21/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada; Institut du savoir Montfort, Hôpital Montfort, Ottawa, Ontario, Canada.
| | - Nicholas Ravanelli
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Jonathan Chevrier
- Department of Epidemiology, Biostatistics and Occupational Health, Faculty of Medicine, McGill University, Québec, Canada
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Ravanelli N, Cramer M, Imbeault P, Jay O. The optimal exercise intensity for the unbiased comparison of thermoregulatory responses between groups unmatched for body size during uncompensable heat stress. Physiol Rep 2017; 5:5/5/e13099. [PMID: 28270588 PMCID: PMC5350162 DOI: 10.14814/phy2.13099] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 11/30/2016] [Indexed: 11/24/2022] Open
Abstract
We sought to identify the appropriate exercise intensity for unbiased comparisons of changes in rectal temperature (ΔTre) and local sweat rates (LSR) between groups unmatched for body size during uncompensable heat stress. Sixteen males vastly different in body morphology were separated into two equal groups [small (SM): 65.8 ± 6.2 kg, 1.8 ± 0.1 m2; large (LG): 100.0 ± 13.1 kg, 2.3 ± 0.1 m2], but matched for sudomotor thermosensitivity (SM: 1.3 ± 0.6; LG: 1.1 ± 0.4 mg·cm−2·min−1·°C−1). The maximum potential for evaporation (Emax) for each participant was assessed using an incremental humidity protocol. On separate occasions, participants then completed 60 min of cycling in a 35°C and 70% RH environment at (1) 50% of VO2max, (2) a heat production (Hprod) of 520 W, (3) Hprod relative to mass (6 W·kg−1), and (4) Hprod relative to mass above Emax (3 W·kg−1>Emax). Emax was similar between LG (347 ± 39 W, 154 ± 15 W·m−2) and SM (313 ± 63 W, 176 ± 34 W·m−2, P > 0.12). ΔTre was greater in SM compared to LG at 520 W (SM: 1.5 ± 0.5; LG 0.8 ± 0.3°C, P < 0.001) and at 50% of VO2max (SM: 1.4 ± 0.5; LG 0.9 ± 0.3°C, P < 0.001). However, ΔTre was similar between groups when Hprod was either 6 W·kg−1 (SM: 0.9 ± 0.3; LG 0.9 ± 0.2°C, P = 0.98) and 3 W·kg−1>Emax (SM: 1.4 ± 0.5; LG 1.3 ± 0.4°C, P = 0.99). LSR was similar between LG and SM irrespective of condition, suggesting maximum LSR was attained (SM: 1.10 ± 0.23; LG: 1.07 ± 0.35 mg·cm−2·min−1, P = 0.50). In conclusion, systematic differences in ΔTre and LSR between groups unmatched for body size during uncompensable heat stress can be avoided by a fixed Hprod in W·kg−1 or W·kg−1>Emax.
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Affiliation(s)
- Nicholas Ravanelli
- School of Human Kinetics, University of Ottawa, Ottawa, Canada.,Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Matthew Cramer
- School of Human Kinetics, University of Ottawa, Ottawa, Canada.,Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas.,The University of Texas Southwestern Medical Center, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Pascal Imbeault
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia .,Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
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Ravanelli N, Coombs G, Duchesne-Belanger S, Imbeault P, Jay O. The Influence Of Aerobic Training On Maximum Skin Wettedness And Its Effects During Uncompensable Heat Stress. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518122.63165.7d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Coombs GB, Cramer MN, Ravanelli N, Imbeault P, Jay O. Thermoregulatory responses to exercise at a fixed rate of heat production are not altered by acute hypoxia. J Appl Physiol (1985) 2017; 122:1198-1207. [PMID: 28302708 DOI: 10.1152/japplphysiol.00829.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 11/22/2022] Open
Abstract
This study sought to assess the within-subject influence of acute hypoxia on exercise-induced changes in core temperature and sweating. Eight participants [1.75 (0.06) m, 70.2 (6.8) kg, 25 (4) yr, 54 (8) ml·kg-1·min-1] completed 45 min of cycling, once in normoxia (NORM; [Formula: see text] = 0.21) and twice in hypoxia (HYP1/HYP2; [Formula: see text]= 0.13) at 34.4(0.2)°C, 46(3)% RH. These trials were designed to elicit 1) two distinctly different %V̇o2peak [NORM: 45 (8)% and HYP1: 62 (7)%] at the same heat production (Hprod) [NORM: 6.7 (0.6) W/kg and HYP1: 7.0 (0.5) W/kg]; and 2) the same %V̇o2peak [NORM: 45 (8)% and HYP2: 48 (5)%] with different Hprod [NORM: 6.7 (0.6) W/kg and HYP2: 5.5 (0.6) W/kg]. At a fixed %V̇o2peak, changes in rectal temperature (ΔTre) and changes in esophageal temperature (ΔTes) were greater at end-exercise in NORM [ΔTre: 0.76 (0.19)°C; ΔTes: 0.64 (0.22)°C] compared with HYP2 [ΔTre: 0.56 (0.22)°C, P < 0.01; ΔTes: 0.42 (0.21)°C, P < 0.01]. As a result of a greater Hprod (P < 0.01) in normoxia, and therefore evaporative heat balance requirements, to maintain a similar %V̇o2peak compared with hypoxia, mean local sweat rates (LSR) from the forearm, upper back, and forehead were greater (all P < 0.01) in NORM [1.10 (0.20) mg·cm-2·min-1] compared with HYP2 [0.71 (0.19) mg·cm-2·min-1]. However, at a fixed Hprod, ΔTre [0.75 (0.24)°C; P = 0.77] and ΔTes [0.63 (0.29)°C; P = 0.69] were not different in HYP1, compared with NORM. Likewise, mean LSR [1.11 (0.20) mg·cm-2·min-1] was not different (P = 0.84) in HYP1 compared with NORM. These data demonstrate, using a within-subjects design, that hypoxia does not independently influence thermoregulatory responses. Additionally, further evidence is provided to support that metabolic heat production, irrespective of %V̇o2peak, determines changes in core temperature and sweating during exercise.NEW & NOTEWORTHY Using a within-subject design, hypoxia does not independently alter core temperature and sweating during exercise at a fixed rate of heat production. These findings also further contribute to the development of a methodological framework for assessing differences in thermoregulatory responses to exercise between various populations and individuals. Using the combined environmental stressors of heat and hypoxia we conclusively demonstrate that exercise intensity relative to aerobic capacity (i.e., %V̇o2max) does not influence changes in thermoregulatory responses.
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Affiliation(s)
- Geoff B Coombs
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Matthew N Cramer
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada.,Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and the University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Nicholas Ravanelli
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada.,Thermal Ergonomics Laboratory, University of Sydney, Lidcombe, New South Wales, Australia
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Ollie Jay
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada; .,Thermal Ergonomics Laboratory, University of Sydney, Lidcombe, New South Wales, Australia
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Ravanelli N, Cramer M, Imbeault P, Jay O. The influence of body morphology on changes in core temperature during exercise in an uncompensable environment. Extrem Physiol Med 2015. [PMCID: PMC4580886 DOI: 10.1186/2046-7648-4-s1-a143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Imbeault P. Persistent Organic Pollutants: Emerging Factors for Obesity and Type 2 Diabetes Prevalence? Can J Diabetes 2015. [DOI: 10.1016/j.jcjd.2015.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Chassé E, Mahat B, Mauger JF, Imbeault P. The Effects of Intermittent Hypoxia, a Simulating Model of Obstructive Sleep Apnea, on Lipid Levels in Healthy Humans. Can J Diabetes 2015. [DOI: 10.1016/j.jcjd.2015.01.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Barsalani R, Riesco É, Perreault K, Imbeault P, Brochu M, Dionne IJ. Variation in C-reactive protein following weight loss in obese insulin resistant postmenopausal women: is there an independent contribution of lean body mass? Exp Clin Endocrinol Diabetes 2015; 123:198-203. [PMID: 25658658 DOI: 10.1055/s-0034-1398551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND We showed that obese insulin resistant postmenopausal women are characterized by higher lean body mass and elevated C-reactive protein. Although counterintuitive, we hypothesized that losses in muscle mass following caloric restriction and increase in muscle quality will be associated with improvements in glucose homeostasis through decreases in C-reactive protein. OBJECTIVES To determine 1) if improvements in C-reactive protein concentrations occurs through losses in lean body mass; and 2) if decreases in C-reactive protein levels contribute to improvements in insulin sensitivity. METHODS 50 postmenopausal women (body mass index>26 kg/m(²)) with impaired glucose disposal (<7.5 mg/kg/min) completed a 6-month caloric restriction program. Outcome measures were: Glucose disposal rate: M value (by hyperinsulinemic-euglycemic clamp), body composition (total, trunk, and appendicluar). LBM and FM by DXA), LBM index (LBM (kg)/height (m(2)), body fat distribution (VAT and SAT by CT scan) and plasma high-sensitive C-reactive protein (hsCRP) and interleukin-6 (Il-6). RESULTS Significant correlations were observed between Δ hsCRP levels with Δ Il-6 (r=0.33, p≤0.05), Δ total LBM index (r=0.44, p≤0.01), Δ trunk LBM (r=0.38, p≤0.01) Δ SAT (r=0.35, p≤0.05) and ∆ glucose disposal rate (r=- 0.44, p≤0.01). After including all the correlated variables in Stepwise linear regression model, Δ LBM index was the only independent predictor of the reduction in hsCRP levels (R(2)=0.20, p≤0.01). CONCLUSION Losses in total lean body mass are independently associated with improvements in inflammatory state (CRP levels) in obese postmenopausal women with impaired glucose disposal.
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Affiliation(s)
- R Barsalani
- Research Centre on Aging, Social Services and Health Centre-University Institute of Geriatrics of Sherbrooke, Sherbrooke, Quebec, Canada
| | - É Riesco
- Research Centre on Aging, Social Services and Health Centre-University Institute of Geriatrics of Sherbrooke, Sherbrooke, Quebec, Canada
| | - K Perreault
- Research Centre on Aging, Social Services and Health Centre-University Institute of Geriatrics of Sherbrooke, Sherbrooke, Quebec, Canada
| | - P Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - M Brochu
- Research Centre on Aging, Social Services and Health Centre-University Institute of Geriatrics of Sherbrooke, Sherbrooke, Quebec, Canada
| | - I J Dionne
- Research Centre on Aging, Social Services and Health Centre-University Institute of Geriatrics of Sherbrooke, Sherbrooke, Quebec, Canada
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Seabert TA, Pal S, Pinet BM, Haman F, Robidoux MA, Imbeault P, Krümmel EM, Kimpe LE, Blais JM. Elevated contaminants contrasted with potential benefits of ω-3 fatty acids in wild food consumers of two remote first nations communities in northern Ontario, Canada. PLoS One 2014; 9:e90351. [PMID: 24598815 PMCID: PMC3943865 DOI: 10.1371/journal.pone.0090351] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/29/2014] [Indexed: 11/18/2022] Open
Abstract
Indigenous communities in Boreal environments rely on locally-harvested wild foods for sustenance. These foods provide many nutritional benefits including higher levels of polyunsaturated fatty acids (PUFAs; such as ω-3) than what is commonly found in store-bought foods. However, wild foods can be a route of exposure to dietary mercury and persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). Here, we show a strong association between the frequency of wild food consumption in adults (N = 72) from two remote First Nations communities of Northern Ontario and environmental contaminants in blood (POPs) and hair (mercury). We observed that POPs and mercury were on average 3.5 times higher among those consuming wild foods more often, with many frequent wild food consumers exceeding Canadian and international health guidelines for PCB and mercury exposures. Contaminants in locally-harvested fish and game from these communities were sufficiently high that many participants exceeded the monthly consumption limits for methylmercury and PCBs. Those consuming more wild foods also had higher proportions of potentially beneficial ω-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These results show that the benefits of traditional dietary choices in Boreal regions of Canada must be weighed against the inherent risks of contaminant exposure from these foods.
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Affiliation(s)
| | - Shinjini Pal
- Department of Biology, University of Ottawa, Ontario, Canada
| | - Bernard M. Pinet
- Indigenous Health Research Group, University of Ottawa, Ottawa, Ontario, Canada
| | - Francois Haman
- Indigenous Health Research Group, University of Ottawa, Ottawa, Ontario, Canada
| | - Michael A. Robidoux
- Indigenous Health Research Group, University of Ottawa, Ottawa, Ontario, Canada
| | - Pascal Imbeault
- Behavioural and Metabolic Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Eva M. Krümmel
- Department of Biology, University of Ottawa, Ontario, Canada
| | - Linda E. Kimpe
- Department of Biology, University of Ottawa, Ontario, Canada
| | - Jules M. Blais
- Department of Biology, University of Ottawa, Ontario, Canada
- * E-mail:
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Myre M, Imbeault P. Persistent organic pollutants meet adipose tissue hypoxia: does cross-talk contribute to inflammation during obesity? Obes Rev 2014; 15:19-28. [PMID: 23998203 DOI: 10.1111/obr.12086] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/08/2013] [Accepted: 08/04/2013] [Indexed: 01/15/2023]
Abstract
Lipophilic persistent organic pollutants (POPs) accumulate in lipid-rich tissues such as human adipose tissue. This is particularly problematic in individuals with excess adiposity, a physiological state that may be additionally characterized by local adipose tissue hypoxia. Hypoxic patches occur when oxygen diffusion is insufficient to reach all hypertrophic adipocytes. POPs and hypoxia independently contribute to the development of adipose tissue-specific and systemic inflammation often associated with obesity. Inflammation is induced by increased proinflammatory mediators such as tumour necrosis factor-alpha, interleukin-6, and monocyte chemotactic protein-1, as well as reduced adiponectin release, an anti-inflammatory and insulin-sensitizing adipokine. The aryl hydrocarbon receptor (AhR) mediates the cellular response to some pollutants, while hypoxia responses occur through the oxygen-sensitive transcription factor hypoxia-inducible factor (HIF)-1. There is some overlap between the two signalling pathways since both require a common subunit called the AhR nuclear translocator. As such, it is unclear how adipocytes respond to simultaneous POP and hypoxia exposure. This brief review explores the independent contribution of POPs and adipose tissue hypoxia as factors underlying the inflammatory response from adipocytes during obesity. It also highlights that the combined effect of POPs and hypoxia through the AhR and HIF-1 signalling pathways remains to be tested.
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Affiliation(s)
- M Myre
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
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Fotsing S, Nzokem AH, Grenier J, Imbeault P, Batal M, Bouchard L, Chomienne MH. Prévalence de la dépression majeure chez les arthritiques des populations canadiennes: étude comparative entre anglophones majoritaires et francophones en situation linguistique minoritaire. Can J Public Health 2013. [DOI: 10.17269/cjph.104.3484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Imbeault P, Makvandi E, Batal M, Gagnon-Arpin I, Grenier J, Chomienne MH, Bouchard L. Physical inactivity among Francophones and Anglophones in Canada. Can J Public Health 2013; 104:S26-30. [PMID: 24300316 DOI: 10.17269/cjph.104.3467] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 06/17/2013] [Accepted: 06/06/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Leisure-time physical activity participation is influenced by various socio-demographic factors. Recent evidence suggests that being part of a minority negatively impacts an individual's health status. The objective of this study was to compare inactive leisure-time physical activity between the Francophone minority and the Anglophone majority in Canada. METHODS Data from the fusion of cycles 2.1, 3.1, 4.1, 2008 and 2009 of the Canadian Community Health Survey (CCHS) were used. The linguistic variable was determined by languages spoken at home, first language learned and still understood, language of interview, and language of preference. Leisure-time physical activity was based on a questionnaire provided during the interview. Factors associated with inactive leisure time were examined using logistic regression models. RESULTS Francophones were more likely than Anglophones to be physically inactive in their leisure time (49.1% vs. 47.2%). A greater percentage of Francophones had poor self-perceived health, were older, were single, had lower education, had higher rate of unemployment and lived in rural areas compared to Anglophones. When these socio-demographic factors were taken into account, there were no further differences in the likelihood of being inactive between Francophones and Anglophones. CONCLUSION The Francophone minority in Canada is characterized by socio-demographic factors that have a negative impact on leisure-time physical activity participation.
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Batal M, Makvandi E, Imbeault P, Gagnon-Arpin I, Grenier J, Chomienne MH, Bouchard L. Comparison of dietary intake between Francophones and Anglophones in Canada: data from CCHS 2.2. Can J Public Health 2013; 104:S31-8. [PMID: 24300318 PMCID: PMC6973893 DOI: 10.17269/cjph.104.3501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 06/12/2013] [Accepted: 06/04/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To compare the dietary intake and food choices between Francophone Canadians in a state of linguistic minority (outside of Quebec) and the English-speaking majority. METHODS We used the 2004 Canadian Community Health Survey (CCHS) cycle 2.2 (general health and 24-hour dietary recalls) to describe dietary intake of Francophone Canadians (excluding Quebec) and compare them to the English-speaking majority. The linguistic variable was determined by languages spoken at home, first language learned and still understood, language of interview, and language of preference. The mean differences in daily nutrient and food intake were assessed by t and chi-square tests. RESULTS Differences in total energy and daily food intakes by language groups were not observed in the sample; however, significant differences in weekly consumption were found in different age and sex categories: lower fruits and vegetables consumption, and vitamins and macronutrients intakes for older Francophone men and higher intakes of energy and saturated fat from "unhealthy" foods for Francophone men 19-30 years of age. Based on the Acceptable Macronutrients Distribution Range (AMDR), approximately 50% of the sample exceeded their acceptable energy intake from saturated fats, and 80% were below their required intake of linoleic fatty acid. CONCLUSION We confirmed that belonging to Francophone minorities in Canada affects food choices and nutritional well-being of this population. The most vulnerable groups identified by our study were Francophone men in the youngest (19-30) and older (50 and over) age categories. The extent to which the cultural setting influences the diet and, in turn, the health of the minority population needs further examination.
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Affiliation(s)
- Malek Batal
- University of Ottawa Réseau de recherche appliquée sur la santé des francophones de l'Ontario (RRASFO).
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Abstract
OBJECTIVES Recent studies show a higher prevalence of being obese or overweight in Francophones living in minority settings compared to Canada's Anglophone majority. The objective of our study was to determine whether belonging to the linguistic minority constituted a social determinant of having a weight problem. METHODS Descriptive variables (n=128,986) from five cycles of the Canadian Community Health Survey were stratified by respondents' language and sex. Two logistic regression models tested the association between being overweight/obese (as defined by the measure of body mass index) and language, for men and women, while adjusting for social and behavioural determinants. RESULTS Prevalence of excess weight was higher among Francophones compared to Anglophones of Ontario, although the difference was not significant after adjustment for socio-economic and behavioural determinants. However, Francophones were older, less educated and more likely to live in rural areas than their Anglophone counterparts, a situation which makes them more vulnerable. CONCLUSION The study confirms the role of social and behavioural determinants of being obese/overweight. Although language does not have a direct influence on having a weight problem, the socio-economic reality of the Francophone minority makes them more likely than the Anglophone majority to fall in vulnerable strata of the population with regards to being overweight/obese. This situation should be considered when planning health services.
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Thrush AB, Antoun G, Boushel R, Doucet É, Imbeault P, McPherson R, Dent R, Harper ME. Investigating The Metabolic Basis for Weight loss Variability in Obese Humans. Can J Diabetes 2013. [DOI: 10.1016/j.jcjd.2013.03.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Myre M, Imbeault P. Inflammatory Responses to Hypoxia and Persistent Organic Pollutants in Human Adipocytes. Can J Diabetes 2013. [DOI: 10.1016/j.jcjd.2013.03.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Mauriège P, Imbeault P, Doucet E, Lacaille M, Langin D, Alméras N, Després JP, Tremblay A. Weight loss and regain in obese individuals: a link with adipose tissue metabolism indices? J Physiol Biochem 2013; 69:497-505. [DOI: 10.1007/s13105-013-0237-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 01/13/2013] [Indexed: 10/27/2022]
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37
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Imbeault P, Findlay CS, Robidoux MA, Haman F, Blais JM, Tremblay A, Springthorpe S, Pal S, Seabert T, Krümmel EM, Maal-Bared R, Tetro JA, Pandey S, Sattar SA, Filion LG. Dysregulation of cytokine response in Canadian First Nations communities: is there an association with persistent organic pollutant levels? PLoS One 2012; 7:e39931. [PMID: 22768323 PMCID: PMC3388062 DOI: 10.1371/journal.pone.0039931] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 05/29/2012] [Indexed: 12/21/2022] Open
Abstract
In vitro and animal studies report that some persistent organic pollutants (POPs) trigger the secretion of proinflammatory cytokines. Whether POP exposure is associated with a dysregulation of cytokine response remains to be investigated in humans. We studied the strength of association between plasma POP levels and circulating cytokines as immune activation markers. Plasma levels of fourteen POPs and thirteen cytokines were measured in 39 Caucasians from a comparator sample in Québec City (Canada) and 72 First Nations individuals from two northern communities of Ontario (Canada). Caucasians showed significantly higher levels of organochlorine insecticides (β-HCH, p,p'-DDE and HCB) compared to First Nations. Conversely, First Nations showed higher levels of Mirex, Aroclor 1260, PCB 153, PCB 170, PCB 180 and PCB 187 compared to Caucasians. While there was no difference in cytokine levels of IL-4, IL-6, IL-10 and IL-22 between groups, First Nations had significantly greater average levels of IFNγ, IL-1β, IL-2, IL-5, IL-8, IL-12p70, IL-17A, TNFα and TNFβ levels compared to Caucasians. Among candidate predictor variables (age, body mass index, insulin resistance and POP levels), high levels of PCBs were the only predictor accounting for a small but significant effect of observed variance (∼7%) in cytokine levels. Overall, a weak but significant association is detected between persistent organochlorine pollutant exposure and elevated cytokine levels. This finding augments the already existing information that environmental pollution is related to inflammation, a common feature of several metabolic disorders that are known to be especially prevalent in Canada's remote First Nations communities.
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Affiliation(s)
- Pascal Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada.
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Drapeau S, Doucet E, Rabasa-Lhoret R, Brochu M, Prud'homme D, Imbeault P. Improvement in insulin sensitivity by weight loss does not affect hyperinsulinemia-mediated reduction in total and high molecular weight adiponectin: a MONET study. Appl Physiol Nutr Metab 2011; 36:191-200. [PMID: 21609280 DOI: 10.1139/h10-106] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute hyperinsulinemia reduces total and high molecular weight (HMW) adiponectin levels in humans. Whether an increase in insulin sensitivity (IS) is accompanied by a greater suppressive effect of hyperinsulinemia on adiponectin levels is unknown, however. To clarify the inhibitory role of insulin on adiponectin, total and HMW adiponectin levels were measured during acute hyperinsulinemia before and after an improvement in insulin sensitivity in response to weight loss. Forty-six overweight and obese postmenopausal women were randomized to either 6-month caloric restriction (CR) alone (n = 22), or CR with resistance training (CR+RT, n = 24). IS (hyperinsulinemic-euglycemic clamp) was assessed before and after weight loss. Total and HMW adiponectin levels were measured by ELISA at baseline, 90, 160, and 180 min of each clamp. Relative mean body weight loss was -8.0% ± 4.4% for both groups (CR: -7.7% ± 3.8%; CR+RT: -8.2% ± 5.0%). IS increased significantly, by 18.4% ± 25.3% (CR: 19.3% ± 29.7%; CR+RT: 17.7% ± 21.0%). Before each intervention, total and HMW adiponectin levels in both groups significantly decreased in response to hyperinsulinemia (total: -8.4% ± 19.4%; HMW: -3.2% ± 13.2%). Despite the improvement in IS seen after each intervention, a similar pattern of reduction to that before weight loss was observed in total and HMW adiponectin levels during hyperinsulinemia. These results establish that total and HMW adiponectin levels decline during a hyperinsulinemic-euglycemic clamp. Also, the insulin-sensitizing effect of weight loss via caloric restriction alone or with resistance training does not amplify the reduction in adiponectin levels observed during hyperinsulinemia in healthy postmenopausal women.
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Affiliation(s)
- Sophie Drapeau
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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Imbeault P, Haman F, Blais JM, Pal S, Seabert T, Krümmel EM, Robidoux MA. Obesity and type 2 diabetes prevalence in adults from two remote first nations communities in northwestern ontario, Canada. J Obes 2011; 2011:267509. [PMID: 21603265 PMCID: PMC3092563 DOI: 10.1155/2011/267509] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/21/2011] [Accepted: 02/15/2011] [Indexed: 01/14/2023] Open
Abstract
Objective. To assess the prevalence rates of obesity and type 2 diabetes in adults from two First Nations communities in northwestern Ontario, Canada. Methods. Body weight, height, and waist circumference as well as fasting and postprandial glucose levels following an oral glucose tolerance test were measured in 31 men and 41 women. Results. The mean age of the sample was 43 ± 13 y. The prevalence of obesity was 65.3% and was comparable between men and women. 90.3% of the individuals presented waist circumference levels greater than the thresholds associated with an increased risk of developing health problems. 26 of the 72 individuals (36.1%) were found to be type 2 diabetic. The prevalence of diabetes was not different between men and women. Conclusion. Using objective measurements, this study confirms that First Nations adults from remote communities of Canada continue to experience a disproportionately higher prevalence of obesity and type 2 diabetes than nonaboriginal Canadians.
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Affiliation(s)
- Pascal Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 125, University Street (room 350), Ottawa, ON, Canada K1N 6N5
- *Pascal Imbeault:
| | - François Haman
- Indigenous Health Group, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Jules M. Blais
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Shinjini Pal
- Indigenous Health Group, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Tim Seabert
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Eva M. Krümmel
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Michael A. Robidoux
- Indigenous Health Group, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada K1N 6N5
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Chapados N, Casimiro C, Batal M, Blais J, Haman F, Robidoux M, Imbeault P. Increased proliferative effect of organochlorine compounds on human preadipocytes. Can J Diabetes 2011. [DOI: 10.1016/s1499-2671(11)52271-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Elisha B, Ziai S, Karelis AD, Rakel A, Coderre L, Imbeault P, Rabasa-Lhoret R. Similar associations of total adiponectin and high molecular weight adiponectin with cardio-metabolic risk factors in a population of overweight and obese postmenopausal women: a MONET study. Horm Metab Res 2010; 42:590-4. [PMID: 20486084 DOI: 10.1055/s-0030-1253404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of the study was to examine the association between total adiponectin and high molecular weight (HMW) adiponectin levels with cardio-metabolic risk factors in a population of sedentary, overweight, and obese postmenopausal women. Cross-sectional study was carried out on 55 nondiabetic sedentary overweight and obese postmenopausal women aged between 50 and 70 years. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp technique. Body composition and visceral fat were measured using dual X-ray absorptiometry and computed tomography, respectively. Other cardio-metabolic risk factors included: plasma lipids, hsC-reactive protein, energy expenditure (doubly labeled water), peak oxygen consumption, muscle strength (using weight training equipment) as well as total and HMW adiponectin. Correlations of total and HMW adiponectin with various cardio-metabolic risk factors were comparable. In addition, regression analysis results showed similar independent predictors of total and HMW adiponectin. Finally, the receiver operator characteristic (ROC) curves for total and HMW adiponectin to predict insulin sensitivity showed no difference between the areas under curve (AUC) (AUC total adiponectin=0.80 [95% CI: 0.66-0.95] versus AUC HMW adiponectin=0.76 [95% CI: 0.60-0.91], p=0.36). The present study indicates that HMW adiponectin does not seem to provide additional information than total adiponectin in relation to cardio-metabolic risk factors in overweight/obese postmenopausal women.
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Affiliation(s)
- B Elisha
- Department of Nutrition, University of Montreal, Montreal, Quebec, Canada
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Elisha B, Karelis AD, Imbeault P, Rabasa-Lhoret R. Effects of acute hyperinsulinaemia on total and high-molecular-weight adiponectin concentration in metabolically healthy but obese postmenopausal women: a Montreal-Ottawa New Emerging Team (MONET) study. Diabetes Metab 2010; 36:319-21. [PMID: 20605505 DOI: 10.1016/j.diabet.2010.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 03/09/2010] [Accepted: 03/11/2010] [Indexed: 12/24/2022]
Abstract
AIM The aim of this study was to determine the differences and changes in total and high-molecular-weight (HMW) adiponectin levels among metabolically healthy but obese (MHO) postmenopausal women in response to acute hyperinsulinaemia. METHOD In this cross-sectional study, 55 non-diabetic overweight and obese postmenopausal women underwent a hyperinsulinaemic-euglycaemic clamp test to evaluate insulin sensitivity. Subjects within the upper tertile of insulin sensitivity were described as 'MHO' (n=18), whereas those within the lowest tertile were considered 'at risk' (n=18). Plasma total and HMW adiponectin levels were measured by ELISA at 0 (baseline), 90, 160 and 180 min during the clamp. RESULTS At baseline and at all time points during the clamp, MHO individuals had significantly higher total and HMW adiponectin levels than at-risk subjects (AUC: total adiponectin=2506 ± 1010 vs 1616 ± 830; HMW adiponectin=909 ± 307 vs 604 ± 349; P<0.05). In addition, a significant reduction in total adiponectin was observed at 160 min and 180 min in at-risk and MHO subjects, respectively, while HMW adiponectin significantly decreased at 160 min in at-risk subjects, and at 90 min as well as 160 min in MHO women. CONCLUSION MHO postmenopausal women had higher levels of plasma total and HMW adiponectin than at-risk subjects at baseline and during the clamp. Furthermore, significant decreases in total and HMW adiponectin were observed at certain time points in both the MHO and at-risk subjects.
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Affiliation(s)
- B Elisha
- Department of Nutrition, Faculty of medicine, University of Montreal, Montreal, Quebec, Canada
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Kasbia GS, Arnason JT, Imbeault P. No effect of acute, single dose oral administration of Momordica charantia Linn., on glycemia, energy expenditure and appetite: a pilot study in non-diabetic overweight men. J Ethnopharmacol 2009; 126:127-33. [PMID: 19665538 DOI: 10.1016/j.jep.2009.07.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 07/20/2009] [Accepted: 07/30/2009] [Indexed: 05/22/2023]
Abstract
AIM OF THE STUDY Momordica charantia Linn. Cucurbitaceae (MC), has been used to treat glycemic impairment in humans for centuries. The objective of this study was to determine the acute effect of MC on postprandial glucose levels, energy expenditure/fuel mixture and appetite in overweight men. MATERIALS AND METHODS Five healthy overweight men were supplemented on three randomized conditions where (1) no MC (placebo), (2) 50 mg/kg body weight (MC50) or (3) 100 mg/kg body weight of freeze dried MC were administered orally prior to a 75 g oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were measured before and during the OGTT. Energy expenditure as well as carbohydrate and lipid oxidation rates were measured by indirect calorimetry. Visual analogue scales were used to rate appetite profile. RESULTS Plasma glucose and insulin levels significantly increased during the OGTT (p < or =0.05) but no significant difference was observed between experimental conditions. Energy expenditure, carbohydrate and lipid oxidation rates as well as appetite profile did not differ between experimental conditions. CONCLUSIONS These results suggest that from an acute standpoint, a freeze dried MC extraction in its present dose form does not affect plasma glucose/insulin levels, energy expenditure, substrate mixture and appetite scores following an oral glucose load in non-diabetic overweight men.
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Affiliation(s)
- Gursevak S Kasbia
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Canada
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Abstract
Sympathetic nerve activation is recognized at the adipose tissue level during cold exposure. Adiponectin is a key protein produced by adipose tissue, but its acute modulation remains unknown in humans exposed to cold. The aim of this study were (1) to examine the acute effects of cold exposure on circulating adiponectin and (2) to determine whether the changes are modulated by (a) an acute glucose ingestion as well as (b) a short-term modulation in carbohydrate (CHO) availability. Using a random crossover design, 6 healthy men were exposed to cold for 120 minutes with ingestion of beverages containing low (Control, 0.04 g/min) or high (High, 0.8 g/min) amounts of glucose during the course of the experiment (study 1). In study 2, 6 healthy men were exposed twice to cold for 120 minutes after equicaloric low-CHO diet and exercise and high-CHO diet without exercise. Plasma adiponectin concentrations were quantified before and during cold exposure. In study 1, adiponectin levels did not change during High, whereas a 20% rise was observed during Control (condition x time interaction, P = .06). In study 2, adiponectin levels increased by approximately 70% during cold exposure after both low- and high-CHO diets (effect of time, P < .05). A 120-minute period of cold exposure is accompanied by a significant increase in adiponectin levels in young healthy men. The rise in adiponectin levels observed during shivering is inhibited with glucose ingestion but not after diets varying in CHO content.
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Affiliation(s)
- Pascal Imbeault
- Behavioural and Metabolic Research Unit (Montfort Hospital), School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada K1N 6N5.
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St-Pierre DH, Cianflone K, Smith J, Coderre L, Karelis AD, Imbeault P, Lavoie JM, Rabasa-Lhoret R. Change in plasma acylation stimulating protein during euglycaemic-hyperinsulinaemic clamp in overweight and obese postmenopausal women: a MONET study. Clin Endocrinol (Oxf) 2009; 70:539-46. [PMID: 18702682 DOI: 10.1111/j.1365-2265.2008.03353.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Acylation-stimulating protein (ASP) has been shown to positively stimulate fatty acid esterification and glucose uptake in adipocytes. In vitro studies demonstrate that insulin stimulates ASP secretion from adipocytes. Individuals with obesity and/or metabolic disturbances (insulin resistance and type 2 diabetes) have increased plasma ASP. DESIGN The present study was designed to evaluate whether ASP levels are influenced by the metabolic profiles of overweight and obese postmenopausal women during a euglycaemic/hyperinsulinaemic clamp (EHC). Patients The study population consisted of 76 overweight and obese sedentary postmenopausal women. MEASUREMENTS We evaluated insulin sensitivity, plasma ASP levels, body composition including visceral adipose tissue area, blood lipid profiles, liver enzymes, peak aerobic capacity, resting metabolic rate (RMR) and total energy expenditure (TEE). RESULTS We observed wide interindividual variations of ASP levels during the EHC. Therefore, subjects were divided into three groups based on ASP changes. Negative ASP Responders (NAR; n = 24) showed a -20% or greater decrease in ASP levels while Positive ASP Responders (PAR; n = 42) displayed ASP fluctuations superior to +20%. Ten subjects had little or no ASP change and were considered as Zero ASP responders (ZAR). PAR women displayed a worse metabolic profile than NAR women, including higher BMI, visceral adipose tissue, fasting insulin levels, lean body mass, and alanine aminotransferase (ALT), a marker of impaired liver function. After adjustment for BMI, only ALT remained significantly different, while lean body mass (P = 0.08) and visceral adipose tissue (P = 0.07) remained marginally higher. Correlation analysis of all subjects demonstrated that fasting ASP levels correlated positively with albumin and VO(2 peak) and this association remained significant after adjustments for the effect of BMI. In addition, the percentage maximal change in ASP levels during the EHC was positively associated with BMI, lean body mass, visceral adipose tissue, fasting insulin, HOMA, TEE, RMR, ALT and AST. CONCLUSION Overall these results suggest that an elevated ASP response during the EHC is associated with metabolic disturbances in overweight and obese postmenopausal women.
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Affiliation(s)
- David H St-Pierre
- Département de Nutrition, Université de Montréal, Montréal, Québec, Canada
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Doucet E, Laviolette M, Imbeault P, Strychar I, Rabasa-Lhoret R, Prud'homme D. Total peptide YY is a correlate of postprandial energy expenditure but not of appetite or energy intake in healthy women. Metabolism 2008; 57:1458-64. [PMID: 18803953 DOI: 10.1016/j.metabol.2008.05.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 05/12/2008] [Indexed: 12/14/2022]
Abstract
Peptide YY (PYY) and ghrelin have been associated with the regulation of energy balance. The objectives of this study were to determine whether total ghrelin and PYY after a standardized meal predict appetite scores and ad libitum energy intake (EI) and to examine the relationship between total ghrelin and PYY and postprandial energy expenditure (PEE). Twenty-five premenopausal women (age, 50.4 +/- 2.0 years; body mass index, 23.5 +/- 2.2 kg/m(2)) were studied. Total PYY, total ghrelin (enzyme-linked immunosorbent assay), EE (indirect calorimetry), and appetite scores (visual analogue scales) were measured fasting and every 30 minute for 3 hours after the ingestion of a standardized breakfast. Ad libitum EI was measured at lunch with a buffet-type meal. Peptide YY increased (P < .001) and total ghrelin decreased (P < .001) after breakfast. Significant changes in EE (P < .001) and appetite scores (P < .001) were noted postprandially. Appetite scores were consistently associated with ad libitum EI at lunch (r = -0.51 to 0.40, P < .05), whereas no association between EI and prelunch total ghrelin and PYY was observed. Finally, partial correlation analyses revealed that total PYY was a significant independent correlate of PEE at 60, 90, 120, and 150 minutes (r = 0.37-0.51, P </= .05). These findings provide evidence that appetite scores are better correlates of EI than are circulating levels of total PYY or ghrelin and that total PYY could be involved in the regulation of PEE.
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Affiliation(s)
- Eric Doucet
- School of Human Kinetics University of Ottawa, Ontario, Canada.
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Dickson C, Maneshi A, Imbeault P, Haman F. Dietary protein may affect acute changes in blood pressure during high stress situations. J Nutr 2007; 137:2814; author reply 2815. [PMID: 18029505 DOI: 10.1093/jn/137.12.2814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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St-Pierre DH, Bastard JP, Coderre L, Brochu M, Karelis AD, Lavoie ME, Malita F, Fontaine J, Mignault D, Cianflone K, Imbeault P, Doucet E, Rabasa-Lhoret R. Association of acylated ghrelin profiles with chronic inflammatory markers in overweight and obese postmenopausal women: a MONET study. Eur J Endocrinol 2007; 157:419-26. [PMID: 17893255 DOI: 10.1530/eje-07-0038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Recent reports have suggested that the existence of associations between hormonal dysregulation and chronic upregulation of inflammatory markers, which may cause obesity-related disturbances. Thus, we examined whether acylated ghrelin (AcylG) and total ghrelin (TotG) levels could be associated with the following inflammatory markers: C-reactive protein (CRP), tumor necrosis factor alpha (TNF-alpha), and soluble TNF receptor 1 (sTNF-R1). DESIGN Cross-sectional study consisting of 50 overweight and obese postmenopausal women. METHODS AcylG and TotG levels were assessed at 0, 60, 160, 170, and 180 min of the euglycemic/hyperinsulinemic clamp (EHC). We evaluated insulin sensitivity, body composition, and blood lipid profiles as well as fasting concentrations of CRP, TNF-alpha, and sTNF-R1. RESULTS In fasting conditions, sTNF-R1 was negatively correlated with AcylG (r = -0.48, P < 0.001) levels. In addition, AcylG/TotG was associated negatively with sTNF-R1 (r = -0.44, P = 0.002) and positively with TNF-alpha (r = 0.38, P = 0.009) values. During the EHC, TotG (at all time points) and AcylG (at 60 and 160 min) values were significantly decreased from fasting concentrations. AcylG maximal reduction and area under the curve (AUC) values were correlated to sTNF-R1 (r = -0.35, P = 0.02 and r = -0.34, P = 0.02, respectively). Meanwhile, the AcylG/TotG AUC ratio was associated negatively with sTNF-R1 (r = -0.29, P < 0.05) and positively with TNF-alpha (r = 0.36, P = 0.02). Following adjustments for total adiposity, sTNF-R1 remained correlated with fasting and maximal reduction AcylG values. Similarly, AcylG/TotG ratios remained significantly correlated with sTNF-R1 and TNF-alpha. Importantly, 23% of the variation in sTNF-R1 was independently predicted by fasting AcylG. CONCLUSION These results are the first to suggest that both fasting and EHC-induced AcylG profiles are correlated with fasting values of sTNF-R1, a component of the TNF-alpha system. Thus, AcylG may act, at least in part, as one mediator of chronic inflammatory activity in human obesity.
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Affiliation(s)
- David H St-Pierre
- Département de Nutrition, Université de Montréal, Montréal, Québec, Canada, H3T 1A8
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Abstract
Sedentary lifestyle, excessive food intake, and consequent overweight and obesity markedly increase the risk of developing some cancers, type 2 diabetes, and cardiovascular disease. This paper briefly summarizes the beneficial impacts of physical activity in protecting against the development of these diseases.
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Affiliation(s)
- Pascal Imbeault
- Behavioural and Metabolic Research Unit, School of Human Kinetics, University of Ottawa, ON K1N 6N5, Canada
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50
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Abstract
In addition to its classic role in the storage and release of nonesterified fatty acids, the adipocyte is now recognized as a critical source of many endocrine signals. Of these signals, adiponectin has been found to promote lipid oxidation and glucose uptake in skeletal muscles and to reduce glucose output in the liver. Because of the effects of adiponectin on these organs, the search for factors or conditions that could positively influence the synthesis of this adipocyte-derived protein has drawn a great deal of interest. This brief review explores the effects of environmental influences such as weight loss, acute food intake, exercise, and cold exposure on circulating adiponectin levels in humans.
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Affiliation(s)
- Pascal Imbeault
- Behavioural and Metabolic Research Unit, School of Human Kinetics, University of Ottawa, Ontario, Canada.
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