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Donadio MVF, Barbosa MA, Vendrusculo FM, Ramirez TI, Santana-Sosa E, Sanz-Santiago V, Perez-Ruiz M. Mechanisms of ventilatory limitation to maximum exercise in children and adolescents with chronic airway diseases. Pediatr Pulmonol 2023; 58:3293-3302. [PMID: 37671821 DOI: 10.1002/ppul.26659] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 08/08/2023] [Accepted: 08/19/2023] [Indexed: 09/07/2023]
Abstract
INTRODUCTION Exercise intolerance is common in chronic airway diseases (CAD), but its mechanisms are still poorly understood. The aim of this study was to evaluate exercise capacity and its association with lung function, ventilatory limitation, and ventilatory efficiency in children and adolescents with cystic fibrosis (CF) and asthma when compared to healthy controls. METHODS Cross-sectional study including patients with mild-to-moderate asthma, CF and healthy children and adolescents. Anthropometric data, lung function (spirometry) and exercise capacity (cardiopulmonary exercise testing) were evaluated. Primary outcomes were peak oxygen consumption (VO2 peak), forced expiratory volume in 1 s (FEV1 ), breathing reserve (BR), ventilatory equivalent for oxygen consumption (VE /VO2 ) and for carbon dioxide production (VE /VCO2 ), both at the ventilatory threshold (VT1 ) and peak exercise. RESULTS Mean age of 147 patients included was 11.8 ± 3.0 years. There were differences between asthmatics and CF children when compared to their healthy peers for anthropometric and lung function measurements. Asthmatics showed lower VO2 peak when compared to both healthy and CF subjects, although no differences were found between healthy and CF patients. A lower BR was found when CF patients were compared to both healthy and asthmatic. Both CF and asthmatic patients presented higher values for VE /VO2 and VE /VCO2 at VT1 when compared to healthy individuals. For both VE /VO2 and VE /VCO2 at peak exercise CF patients presented higher values when compared to their healthy peers. CONCLUSION Patients with CF achieved good exercise capacity despite low ventilatory efficiency, low BR, and reduced lung function. However, asthmatics reported reduced cardiorespiratory capacity and normal ventilatory efficiency at peak exercise. These results demonstrate differences in the mechanisms of ventilatory limitation to maximum exercise testing in children and adolescents with CAD.
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Affiliation(s)
- Márcio Vinícius Fagundes Donadio
- Department of Physiotherapy, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya (UIC), Barcelona, Spain
- Laboratory of Pediatric Physical Activity, Infant Center, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Marta Amor Barbosa
- Department of Physiotherapy, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Fernanda Maria Vendrusculo
- Laboratory of Pediatric Physical Activity, Infant Center, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Tamara Iturriaga Ramirez
- Department of Physiotherapy, Faculty of Sport Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Spain
| | - Elena Santana-Sosa
- Department of Physiotherapy, Faculty of Sport Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Spain
| | - Veronica Sanz-Santiago
- Department of Pulmonology, Hospital Universitario Infantil Niño Jesús de Madrid, Madrid, Spain
| | - Margarita Perez-Ruiz
- Department of Health and Human Performance, Faculty of Physical Activity and Sport Sciences-INEF, Universidad Politécnica de Madrid (UPM), Madrid, Spain
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Abe C, Katayama C, Bazek M, Ohbayashi K, Horii K, Tanida M, Nin F, Iwasaki Y. Hepatic glycogenolysis and hypometabolism induced by chemogenetic stimulation of C1 neurons. J Physiol 2023. [PMID: 37126218 DOI: 10.1113/jp284319] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/27/2023] [Indexed: 05/02/2023] Open
Abstract
The precise regulation of blood glucose levels is indispensable for maintaining physiological functions. C1 neurons determine the outflow of the autonomic nervous and endocrine systems to maintain blood glucose levels in the body. In contrast, activation of C1 neurons induces a decrease in activity, suggesting that hypoactivity also participates in maintaining blood glucose levels. To examine this, we evaluated both glycogenolysis and hypometabolism induced by the selective activation of C1 neurons. We used DbhCre/0 mice expressing receptors for chemogenetic tools in C1 neurons, owing to microinjection of the viral vector. C1 neurons were activated by intraperitoneal injection of clozapine N-oxide (CNO). The chemogenetic activation of C1 neurons significantly decreased body temperature, oxygen consumption, and carbon dioxide production. On the other hand, the blood glucose level was increased by the activation of C1 neurons 2 h after CNO administration, even in the fasting state. In this situation, an increase in glucagon and corticosterone levels was observed, while hepatic glycogen content decreased significantly. Plasma insulin level was not changed by the activation of C1 neurons despite the blood glucose level increased. Furthermore, adrenal sympathetic nerve activity was significantly increased by the activation of C1 neurons, and plasma catecholamine levels increased significantly. In conclusion, the selective activation of C1 neurons using chemogenetic tools induced an increase in blood glucose level, probably because of hepatic glycogenolysis and hypometabolism. KEY POINTS: Chemogenetic activation of C1 neurons in medulla oblongata decreased body temperature. Oxygen consumption and carbon dioxide production were decreased by chemogenetic activation of C1 neurons in medulla oblongata. Blood glucose level was increased by chemogenetic activation of C1 neurons in medulla oblongata. Chemogenetic activation of C1 neurons in medulla oblongata increased glucagon, corticosterone, and catecholamine levels in plasma. Increase in blood glucose level by activation of C1 neurons occurred due to combined effect of hepatic glycogenolysis and hypometabolism. Abstract figure legend We investigated the effects of selectively activating C1 neurons using chemogenetic tools on blood glucose levels. The activation of C1 neurons resulted in an increase in blood glucose levels. This increase is due to the activation of hepatic glycogenolysis through the release of humoral factors, including adrenaline, glucagon, and corticosterone. Additionally, the decrease in energy expenditure, as evidenced by a reduction in body temperature, oxygen consumption, and carbon dioxide production, suggests that activation of C1 neurons may induce hypometabolism, which could also contribute to an increase in blood glucose levels. These responses indicate that C1 neurons may serve as a switch for energy conservation to maintain blood glucose levels, presumably by being activated in a stressful situation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
- Preemptive Food Research Center (PFRC), Gifu University Institute for Advanced Study, Gifu, Japan
| | - Chikako Katayama
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Murat Bazek
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Kento Ohbayashi
- Laboratory of Animal Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Japan
| | - Kazuhiro Horii
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Mamoru Tanida
- Department of Physiology II, Kanazawa Medical University, Ishikawa, Japan
| | - Fumiaki Nin
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yusaku Iwasaki
- Laboratory of Animal Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Japan
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Silva-Gburek J, Zhu PH, Mansour M, Walding D, Coss-Bu JA. A methodological and clinical approach to measured energy expenditure in the critically ill pediatric patient. Front Pediatr 2022; 10:1027358. [PMID: 36353257 PMCID: PMC9638495 DOI: 10.3389/fped.2022.1027358] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
The metabolic response to injury and stress is characterized initially by a decreased energy expenditure (Ebb phase) followed by an increased metabolic expenditure (Flow phase). Indirect calorimetry is a methodology utilized to measure energy expenditure and substrate utilization by measuring gas exchange in exhaled air and urinary nitrogen. The use of indirect calorimetry in critically ill patients requires precise equipment to obtain accurate measurements. The most recent guidelines suggested that measured energy expenditure by indirect calorimetry be used to determine energy requirements. This article reviews the methodological and clinical use of indirect calorimetry in critically ill pediatric patients.
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Affiliation(s)
- Jaime Silva-Gburek
- Pediatric Critical Care Medicine, Children's Mercy Hospital, University of Missouri-Kansas City School of Medicine, Kansas City, MO, United States
| | - Paola Hong Zhu
- Division of Critical Care, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States.,Texas Children's Hospital, Houston, TX, United States
| | - Marwa Mansour
- Division of Critical Care, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States.,Texas Children's Hospital, Houston, TX, United States
| | - David Walding
- Texas Children's Hospital, Houston, TX, United States.,Department of Biomedical Engineering, Texas Children's Hospital, Houston, TX, United States
| | - Jorge A Coss-Bu
- Division of Critical Care, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States.,Texas Children's Hospital, Houston, TX, United States
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Gautam UK, Hlávková D, Shaik HA, Karaca I, Karaca G, Sezen K, Kodrík D. Adipokinetic Hormones Enhance the Efficacy of the Entomopathogenic Fungus Isaria fumosorosea in Model and Pest Insects. Pathogens 2020; 9:pathogens9100801. [PMID: 32998278 PMCID: PMC7600585 DOI: 10.3390/pathogens9100801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 08/25/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 01/13/2023] Open
Abstract
Insect adipokinetic hormones (AKHs) are neuropeptides with a wide range of actions, including the control of insect energy metabolism. These hormones are also known to be involved in the insect defence system against toxins and pathogens. In this study, our aim was to demonstrate whether the application of external AKHs significantly enhances the efficacy of the entomopathogenic fungus Isaria fumosorosea in a model species (firebug Pyrrhocoris apterus) and pest species (Egyptian cotton leafworm Spodoptera littoralis and pea aphid Acyrthosiphon pisum). It was found that the co-application of Isaria with AKHs significantly enhanced insect mortality in comparison to the application of Isaria alone. The mode of action probably involves an increase in metabolism that is caused by AKHs (evidenced by the production of carbon dioxide), which accelerates the turnover of Isaria toxins produced into the infected insects. However, several species-specific differences probably exist. Intoxication by Isaria elicited the stimulation of Akh gene expression and synthesis of AKHs. Therefore, all interactions between Isaria and AKH actions as well as their impact on insect physiology from a theoretical and practical point of view need to be discussed further.
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Affiliation(s)
- Umesh Kumar Gautam
- Department of Biochemistry and Physiology, Institute of Entomology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (U.K.G.); (D.H.); (H.A.S.)
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
- Department of Plant Protection, Faculty of Agriculture, Isparta University of Applied Sciences, 32260 Isparta, Turkey; (I.K.); (G.K.)
- Department of Biology, Faculty of Science, Karadeniz Technical University, 61080 Trabzon, Turkey;
| | - Daniela Hlávková
- Department of Biochemistry and Physiology, Institute of Entomology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (U.K.G.); (D.H.); (H.A.S.)
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
| | - Haq Abdul Shaik
- Department of Biochemistry and Physiology, Institute of Entomology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (U.K.G.); (D.H.); (H.A.S.)
| | - Ismail Karaca
- Department of Plant Protection, Faculty of Agriculture, Isparta University of Applied Sciences, 32260 Isparta, Turkey; (I.K.); (G.K.)
| | - Gürsel Karaca
- Department of Plant Protection, Faculty of Agriculture, Isparta University of Applied Sciences, 32260 Isparta, Turkey; (I.K.); (G.K.)
| | - Kazim Sezen
- Department of Biology, Faculty of Science, Karadeniz Technical University, 61080 Trabzon, Turkey;
| | - Dalibor Kodrík
- Department of Biochemistry and Physiology, Institute of Entomology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (U.K.G.); (D.H.); (H.A.S.)
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
- Correspondence:
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Abstract
Volume capnography provides a noninvasive, continuous display of the fractional concentration or partial pressure of carbon dioxide (Pco2) versus exhaled volume. Derived measurements and calculations are influenced by changes in both ventilation and perfusion and are therefore useful for assessing both respiratory and cardiovascular function. This article provides an evidence-based review of several potential uses of volume capnography in the intensive care unit: 1) monitoring the effectiveness of ventilation by using end-tidal Pco2 as a surrogate for arterial Pco2, 2) assessing volume responsiveness, 3) measuring cardiac output, 4) determining prognosis in patients with the acute respiratory distress syndrome, 5) optimizing alveolar recruitment, and 6) excluding pulmonary embolism. Studies performed during the past few decades have clearly shown that volume capnography can provide important prognostic information in patients with acute respiratory distress syndrome and that end-tidal Pco2 should not be used to estimate or even to monitor the direction of change in the arterial Pco2 in mechanically ventilated intensive care unit patients. Unfortunately, few conclusions can be made from studies evaluating other potential applications. Of these, the most promising are the noninvasive measurement of cardiac output and optimization of alveolar recruitment in patients with acute respiratory distress syndrome and in mechanically ventilated, morbidly obese patients.
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Sun ZG, Tian G, Zheng XC, Liu WY, Luo XT, Xiao J, Song H, Xu X. AMPKα2 Deficiency Does Not Affect the Exercise-Induced Improvements in Glucose Tolerance and Metabolic Disorders in Mice Fed a High-Fat Diet. J Nutr Sci Vitaminol (Tokyo) 2020; 65:491-497. [PMID: 31902862 DOI: 10.3177/jnsv.65.491] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exercise can improve obesity and metabolic disorders in mice fed a high-fat diet (HFD), but the role of AMPKα2 in the process remains unclear. The aim of this study was to investigate the role of AMPKα2 in the exercise-induced improvements in glucose tolerance and metabolic turnover in obesity mice. Male wild-type mice (n=12) and AMPKα2 knockout (AMPKα2 KO) mice (n=12) were fed a HFD for 16 wk and were then randomly divided into four groups: WT HFD group (WT HF), AMPKα2 KO HFD group (AMPKα2 KO HF), WT HFD exercise group (WT HE), and AMPK HFD exercise group (AMPKα2 KO HE). The HF groups continue to be fed a HFD from 16 wk to 24 wk, and the HE groups were fed a HFD and performed exercise training. After 8 wk of exercise, all mice were placed in an energy metabolism chamber to test their metabolic turnover, include locomotor activity, food intake, oxygen consumption (VO2), carbon dioxide production (VCO2), energy expenditure (EE) and respiratory exchange ratio (RER), over a period of 3 d. Exercise improved glucose tolerance, VO2, VCO2 and EE in mice fed a HFD (p<0.05). The VO2, VCO2 and EE in AMPKα2 KO HE group were lower than these in WT HE group (p<0.05). Our findings revealed exercise improved glucose tolerance and metabolic disorders in C57 and AMPKα2 KO mice fed a HFD. AMPKα2 is not essential for exercise-induced improvements in glucose tolerance and metabolic disorders.
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Affiliation(s)
- Zhong-Guang Sun
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Ge Tian
- Beijing Xian Nong Tan Sports Technical College
| | - Xiao-Ci Zheng
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Wen-Ying Liu
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Xue-Ting Luo
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Jing Xiao
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Hui Song
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Xin Xu
- Department of Exercise Rehabilitation, Shanghai University of Sport
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Vavilin VA, Rytov SV, Lokshina LY. Modelling the specific pathway of CH 4 and CO 2 formation using carbon isotope fractionation: an example for a boreal mesotrophic fen. Isotopes Environ Health Stud 2018; 54:475-493. [PMID: 29807459 DOI: 10.1080/10256016.2018.1478820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 06/15/2017] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
We described mathematically the process of peat methanization in a boreal mesotrophic fen. Gaseous and dissolved CH4 and CO2 as well as their δ13C signatures were considered in the dynamic equations for incubation bottles. In accordance with the model, acetate, H2, and CO2 were produced during cellulose hydrolysis and acidogenesis. 13C/12C in CO2 was a key variable reflecting dynamic changes in the rates of cellulose hydrolysis and acidogenesis, acetoclastic and hydrogenotrophic methanogenesis. As CO2 is the substrate in hydrogenotrophic methanogenesis, δ13C-CO2 increased from the start till the dissolved hydrogen concentration became very low. Thereafter, the rate of acetoclastic methanogenesis with the significant current acetate concentration dominated over the rate of hydrogenotrophic methanogenesis leading to the decreasing δ13C-CO2 and the increasing δ13C-CH4. The model was validated by describing the system's dynamics under strong and weak inhibition of acetoclastic and hydrogenotrophic methanogenesis by methyl fluoride, respectively. During peat methanization at the lowered temperature of 10 °C, the processes of hydrogenotrophic methanogenesis and homoacetogenesis competing for H2 may occur. However, based on dynamics of the carbon isotope signatures, especially on dynamics of δ13C-CO2, the model showed no significant contribution of homoacetogens in peat methanization.
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Affiliation(s)
- Vasily A Vavilin
- a Ecological Department , Water Problems Institute, Russian Academy of Sciences , Moscow , Russian Federation
| | - Sergey V Rytov
- a Ecological Department , Water Problems Institute, Russian Academy of Sciences , Moscow , Russian Federation
| | - Lyudmila Y Lokshina
- a Ecological Department , Water Problems Institute, Russian Academy of Sciences , Moscow , Russian Federation
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Knight JD, Cessna AJ, Ngombe D, Wolfe TM. Mineralisation and degradation of 2,4-dichlorophenoxyacetic acid dimethylamine salt in a biobed matrix and in topsoil. Pest Manag Sci 2016; 72:1965-1976. [PMID: 26818964 DOI: 10.1002/ps.4238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 09/25/2015] [Revised: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND Biobeds are used for on-farm bioremediation of pesticides in sprayer rinsate and from spills during sprayer filling. Using locally sourced materials from Saskatchewan, Canada, a biobed matrix was evaluated for its effectiveness for mineralising and degrading 2,4-dichlorophenoxyacetic acid dimethylamine salt (2,4-D DMA) compared with the topsoil used in the biobed matrix. RESULTS Applying 2,4-D DMA to the biobed matrix caused a 2-3 day lag in CO2 production not observed when the herbicide was applied to topsoil. Despite the initial lag, less residual 2,4-D was measured in the biobed (0%) matrix than in the topsoil (57%) after a 28 day incubation. When the herbicide was applied 5 times to the biobed matrix, net CO2 increased immediately after each 2,4-D DMA application. Mineralisation of 2,4-D DMA was 61.9% and residual 2,4-D in the biobed matrix was 0.3% after 60 days, compared with corresponding values of 32.9 and 70.9% in topsoil. CONCLUSION The biobed matrix enhanced the mineralisation and degradation of 2,4-D DMA, indicating the potential for successful implementation of biobeds under Canadian conditions. The biobed matrix was more effective for mineralising and degrading the herbicide compared with the topsoil used in the biobed matrix. By correcting for biobed matrix and formulation blank, CO2 evolution was a reliable indicator of 2,4-D DMA mineralisation. © 2016 Society of Chemical Industry.
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Affiliation(s)
- J Diane Knight
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Allan J Cessna
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
| | - Dean Ngombe
- Integrated Crop Management Services, Saskatoon, Saskatchewan, Canada
| | - Tom M Wolfe
- Agrimetrix Research and Training, Saskatoon, Saskatchewan, Canada
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Li Y, Wong K, Giles A, Jiang J, Lee JW, Adams AC, Kharitonenkov A, Yang Q, Gao B, Guarente L, Zang M. Hepatic SIRT1 attenuates hepatic steatosis and controls energy balance in mice by inducing fibroblast growth factor 21. Gastroenterology 2014; 146:539-49.e7. [PMID: 24184811 PMCID: PMC4228483 DOI: 10.1053/j.gastro.2013.10.059] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [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: 02/12/2013] [Revised: 09/22/2013] [Accepted: 10/24/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The hepatocyte-derived hormone fibroblast growth factor 21 (FGF21) is a hormone-like regulator of metabolism. The nicotinamide adenine dinucleotide-dependent deacetylase SIRT1 regulates fatty acid metabolism through multiple nutrient sensors. Hepatic overexpression of SIRT1 reduces steatosis and glucose intolerance in obese mice. We investigated mechanisms by which SIRT1 controls hepatic steatosis in mice. METHODS Liver-specific SIRT1 knockout (SIRT1 LKO) mice and their wild-type littermates (controls) were divided into groups that were placed on a normal chow diet, fasted for 24 hours, or fasted for 24 hours and then fed for 6 hours. Liver tissues were collected and analyzed by histologic examination, gene expression profiling, and real-time polymerase chain reaction assays. Human HepG2 cells were incubated with pharmacologic activators of SIRT1 (resveratrol or SRT1720) and mitochondrion oxidation consumption rate and immunoblot analyses were performed. FGF21 was overexpressed in SIRT1 LKO mice using an adenoviral vector. Energy expenditure was assessed by indirect calorimetry. RESULTS Prolonged fasting induced lipid deposition in livers of control mice, but severe hepatic steatosis in SIRT1 LKO mice. Gene expression analysis showed that fasting up-regulated FGF21 in livers of control mice but not in SIRT1 LKO mice. Decreased hepatic and circulating levels of FGF21 in fasted SIRT1 LKO mice were associated with reduced hepatic expression of genes involved in fatty acid oxidation and ketogenesis, and increased expression of genes that control lipogenesis, compared with fasted control mice. Resveratrol or SRT1720 each increased the transcriptional activity of the FGF21 promoter (-2070/+117) and levels of FGF21 messenger RNA and protein in HepG2 cells. Surprisingly, SIRT1 LKO mice developed late-onset obesity with impaired whole-body energy expenditure. Hepatic overexpression of FGF21 in SIRT1 LKO mice increased the expression of genes that regulate fatty acid oxidation, decreased fasting-induced steatosis, reduced obesity, increased energy expenditure, and promoted browning of white adipose tissue. CONCLUSIONS SIRT1-mediated activation of FGF21 prevents liver steatosis caused by fasting. This hepatocyte-derived endocrine signaling appears to regulate expression of genes that control a brown fat-like program in white adipose tissue, energy expenditure, and adiposity. Strategies to activate SIRT1 or FGF21 could be used to treat fatty liver disease and obesity.
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Affiliation(s)
- Yu Li
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
| | - Kimberly Wong
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118
| | - Amber Giles
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118
| | - Jianwei Jiang
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118
| | - Jong Woo Lee
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118
| | - Andrew C. Adams
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana, USA
| | | | - Qin Yang
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20892
| | - Leonard Guarente
- Department of Biology, Paul F. Glenn Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139
| | - Mengwei Zang
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
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Abstract
Cardiorespiratory fitness (CRF) is one of the most important health metrics in apparently healthy individuals, those at increased risk for cardiovascular (CV) disease and virtually all patient populations. In addition to CRF, a host of other variables obtained from aerobic exercise testing provides clinically valuable information. Individuals classified as obese (i.e. a body mass index ≥30 kg/m(2)) have varying degrees of CV, pulmonary and skeletal muscle dysfunction that impact CRF and other key aerobic exercise testing variables. Moreover, there is now evidence indicating inspiratory and expiratory respiratory muscle function, even in the absence of interstitial lung disease, is potentially compromised as a result of obesity. When obesity-induced respiratory muscle dysfunction is present, it has the potential to contribute to the limitations in CRF. The current review will discuss aerobic exercise testing and the assessment of respiratory muscle function in the obese population.
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Crisafulli A. In response to the comments by Fernandes et al. J Physiol Sci 2013; 63:317-8. [PMID: 23637018 PMCID: PMC10717994 DOI: 10.1007/s12576-013-0266-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 04/15/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Antonio Crisafulli
- Department of Medical Sciences, Sports Physiology Lab., University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy
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Hernandez TL, Ballard RD, Weil KM, Shepard TY, Scherzinger AL, Stamm ER, Sharp TA, Eckel RH. Effects of maintained weight loss on sleep dynamics and neck morphology in severely obese adults. Obesity (Silver Spring) 2009; 17:84-91. [PMID: 18948968 PMCID: PMC3350806 DOI: 10.1038/oby.2008.485] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The goals of the study were to determine if moderate weight loss in severely obese adults resulted in (i) reduction in apnea/hypopnea index (AHI), (ii) improved pharyngeal patency, (iii) reduced total body oxygen consumption (VO(2)) and carbon dioxide production (VCO(2)) during sleep, and (iv) improved sleep quality. The main outcome was the change in AHI from before to after weight loss. Fourteen severely obese (BMI > 40 kg/m(2)) patients (3 males, 11 females) completed a highly controlled weight reduction program which included 3 months of weight loss and 3 months of weight maintenance. At baseline and postweight loss, patients underwent pulmonary function testing, polysomnography, and magnetic resonance imaging (MRI) to assess neck morphology. Weight decreased from 134 +/-6.6 kg to 118 +/- 6.1 kg (mean +/- s.e.m.; F = 113.763, P < 0.0001). There was a significant reduction in the AHI between baseline and postweight loss (subject, F = 11.11, P = 0.007). Moreover, patients with worse sleep-disordered breathing (SDB) at baseline had the greatest improvements in AHI (group, F = 9.00, P = 0.005). Reductions in VO(2) (285 +/- 12 to 234 +/-16 ml/min; F = 24.85, P < 0.0001) and VCO(2) (231 +/- 9 to 186 +/- 12 ml/min; F = 27.74, P < 0.0001) were also observed, and pulmonary function testing showed improvements in spirometry parameters. Sleep studies revealed improved minimum oxygen saturation (minSaO(2)) (83.4 +/- 61.9% to 89.1 +/- 1.2%; F = 7.59, P = 0.016), and mean SaO(2) (90.4 +/- 1.1% to 93.8 +/- 1.0%; F = 6.89, P = 0.022), and a significant increase in the number of arousals (8.1 +/- 1.4 at baseline, to 17.1 +/- 3.0 after weight loss; F = 18.13, P = 0.001). In severely obese patients, even moderate weight loss (approximately 10%) boasts substantial benefit in terms of the severity of SDB and sleep dynamics.
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Affiliation(s)
- Teri L Hernandez
- Division of Endocrinology, University of Colorado Denver, Aurora, Colorado, USA.
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Jakovljevic DG, Nunan D, Donovan G, Hodges LD, Sandercock GRH, Brodie DA. Lack of agreement between gas exchange variables measured by two metabolic systems. J Sports Sci Med 2008; 7:15-22. [PMID: 24150129 PMCID: PMC3763340] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 10/30/2007] [Indexed: 06/02/2023]
Abstract
The purpose of this study was to assess the agreement and consistency between gas exchange variables measured by two online metabolic systems during an incremental exercise test. After obtaining local ethics approval and informed consent, 15 healthy subjects performed an incremental exercise test to volitional fatigue using the Bruce protocol. The Innocor (Innovision, Denmark) and CardiO2 (Medical Graphics, USA) systems were placed in series, with the Innocor mouthpiece attached to the pneumotach of the CardiO2. Metabolic data were analysed during the last 30 seconds of each stage and at peak exercise. There were non- significant differences (p > 0.05) between the two systems in estimation of oxygen consumption (VO2) and in minute ventilation (VE). Mean Cronbach's alpha for VO2 and VE were 0.88 and 0.92. The Bland-Altman analysis revealed that limits of agreement were -0.52 to 0.55 l.min(-1) for VO2, and -8.74 to 10.66 l.min(-1) for VE. Carbon dioxide production (VCO2) and consequently respiratory exchange ratio (RER) measured by the Innocor were significantly lower (p < 0.05) through all stages. The CardiO2 measured fraction of expired carbon dioxide (FeCO2) significantly higher (p < 0.05). The limits of agreement for VO2 and VE are wide and unacceptable in cardio-pulmonary exercise testing. The Innocor reported VCO2 systematically lower. Therefore the Innocor and CardiO2 metabolic systems cannot be used interchangeably without affecting the diagnosis of an individual patient. Results from the present study support previous suggestion that considerable care is needed when comparing metabolic data obtained from different automated metabolic systems. Key pointsThere is general concern regarding the limited knowledge available about the accuracy of a number of commercially available systems.Demonstrated limits of agreement between key gas exchange variables (oxygen consumption and minute ventilation) as measured by the two metabolic systems were wide and unacceptable in cardio-pulmonary exercise testing.Considerable care is needed when comparing metabolic data obtained from different automated metabolic systems.
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Affiliation(s)
- Djordje G Jakovljevic
- Research Centre for Society and Health, Buckinghamshire New University , Buckinghamshire, UK
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