1
|
Ivić V, Zjalić M, Blažetić S, Fenrich M, Labak I, Scitovski R, Szűcs KF, Ducza E, Tábi T, Bagamery F, Szökő É, Vuković R, Rončević A, Mandić D, Debeljak Ž, Berecki M, Balog M, Seres-Bokor A, Sztojkov-Ivanov A, Hajagos-Tóth J, Gajović S, Imširović A, Bakula M, Mahiiovych S, Gaspar R, Vari SG, Heffer M. Elderly rats fed with a high-fat high-sucrose diet developed sex-dependent metabolic syndrome regardless of long-term metformin and liraglutide treatment. Front Endocrinol (Lausanne) 2023; 14:1181064. [PMID: 37929025 PMCID: PMC10623428 DOI: 10.3389/fendo.2023.1181064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/25/2023] [Indexed: 11/07/2023] Open
Abstract
Aim/Introduction The study aimed to determine the effectiveness of early antidiabetic therapy in reversing metabolic changes caused by high-fat and high-sucrose diet (HFHSD) in both sexes. Methods Elderly Sprague-Dawley rats, 45 weeks old, were randomized into four groups: a control group fed on the standard diet (STD), one group fed the HFHSD, and two groups fed the HFHSD along with long-term treatment of either metformin (HFHSD+M) or liraglutide (HFHSD+L). Antidiabetic treatment started 5 weeks after the introduction of the diet and lasted 13 weeks until the animals were 64 weeks old. Results Unexpectedly, HFHSD-fed animals did not gain weight but underwent significant metabolic changes. Both antidiabetic treatments produced sex-specific effects, but neither prevented the onset of prediabetes nor diabetes. Conclusion Liraglutide vested benefits to liver and skeletal muscle tissue in males but induced signs of insulin resistance in females.
Collapse
Affiliation(s)
- Vedrana Ivić
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Milorad Zjalić
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Senka Blažetić
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Matija Fenrich
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Irena Labak
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Rudolf Scitovski
- School of Applied Mathematics and Computer Science, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Kálmán Ferenc Szűcs
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Eszter Ducza
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, Szeged, Hungary
| | - Tamás Tábi
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
| | - Fruzsina Bagamery
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
| | - Éva Szökő
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
| | - Rosemary Vuković
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Alen Rončević
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
- Department of Neurosurgery, Osijek University Hospital, Osijek, Croatia
| | - Dario Mandić
- Clinical Institute of Laboratory Diagnostics, Osijek University Hospital, Osijek, Croatia
- Department of Medical Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Željko Debeljak
- Clinical Institute of Laboratory Diagnostics, Osijek University Hospital, Osijek, Croatia
- Department of Pharmacology, Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Monika Berecki
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Marta Balog
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Adrienn Seres-Bokor
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, Szeged, Hungary
| | - Anita Sztojkov-Ivanov
- Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, Szeged, Hungary
| | - Judit Hajagos-Tóth
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Srećko Gajović
- Croatian Institute for Brain Research, and BIMIS - Biomedical Research Institute Šalata, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Alen Imširović
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Marina Bakula
- Department of Clinical Pathology and Forensic Medicine, Osijek University Hospital, Osijek, Croatia
| | - Solomiia Mahiiovych
- Department of Therapy № 1 and Medical Diagnostics, Hematology and Transfusiology, Faculty of Postgraduate Education, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Robert Gaspar
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Sandor G. Vari
- Cedars-Sinai Medical Center, International Research and Innovation in Medicine Program, Los Angeles, CA, United States
| | - Marija Heffer
- Department of Medical Biology and Genetics, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| |
Collapse
|
2
|
Egawa T, Ohno Y, Goto A, Yokoyama S, Hayashi T, Goto K. AMPK Mediates Muscle Mass Change But Not the Transition of Myosin Heavy Chain Isoforms during Unloading and Reloading of Skeletal Muscles in Mice. Int J Mol Sci 2018; 19:ijms19102954. [PMID: 30262782 PMCID: PMC6212939 DOI: 10.3390/ijms19102954] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/25/2022] Open
Abstract
5′AMP-activated protein kinase (AMPK) plays an important role in the regulation of skeletal muscle mass and fiber-type distribution. However, it is unclear whether AMPK is involved in muscle mass change or transition of myosin heavy chain (MyHC) isoforms in response to unloading or increased loading. Here, we checked whether AMPK controls muscle mass change and transition of MyHC isoforms during unloading and reloading using mice expressing a skeletal-muscle-specific dominant-negative AMPKα1 (AMPK-DN). Fourteen days of hindlimb unloading reduced the soleus muscle weight in wild-type and AMPK-DN mice, but reduction in the muscle mass was partly attenuated in AMPK-DN mice. There was no difference in the regrown muscle weight between the mice after 7 days of reloading, and there was concomitantly reduced AMPKα2 activity, however it was higher in AMPK-DN mice after 14 days reloading. No difference was observed between the mice in relation to the levels of slow-type MyHC I, fast-type MyHC IIa/x, and MyHC IIb isoforms following unloading and reloading. The levels of 72-kDa heat-shock protein, which preserves muscle mass, increased in AMPK-DN-mice. Our results indicate that AMPK mediates the progress of atrophy during unloading and regrowth of atrophied muscles following reloading, but it does not influence the transition of MyHC isoforms.
Collapse
Affiliation(s)
- Tatsuro Egawa
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
- Laboratory of Health and Exercise Sciences, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
| | - Yoshitaka Ohno
- Laboratory of Physiology, School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
| | - Ayumi Goto
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
| | - Shingo Yokoyama
- Laboratory of Physiology, School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
| | - Tatsuya Hayashi
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
| | - Katsumasa Goto
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
- Laboratory of Physiology, School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi 440-8511, Japan.
| |
Collapse
|
3
|
Egawa T, Goto A, Ohno Y, Yokoyama S, Ikuta A, Suzuki M, Sugiura T, Ohira Y, Yoshioka T, Hayashi T, Goto K. Involvement of AMPK in regulating slow-twitch muscle atrophy during hindlimb unloading in mice. Am J Physiol Endocrinol Metab 2015; 309:E651-62. [PMID: 26244519 DOI: 10.1152/ajpendo.00165.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/03/2015] [Indexed: 01/08/2023]
Abstract
AMPK is considered to have a role in regulating skeletal muscle mass. However, there are no studies investigating the function of AMPK in modulating skeletal muscle mass during atrophic conditions. In the present study, we investigated the difference in unloading-associated muscle atrophy and molecular functions in response to 2-wk hindlimb suspension between transgenic mice overexpressing the dominant-negative mutant of AMPK (AMPK-DN) and their wild-type (WT) littermates. Male WT (n = 24) and AMPK-DN (n = 24) mice were randomly divided into two groups: an untreated preexperimental control group (n = 12 in each group) and an unloading (n = 12 in each group) group. The relative soleus muscle weight and fiber cross-sectional area to body weight were decreased by ∼30% in WT mice by hindlimb unloading and by ∼20% in AMPK-DN mice. There were no changes in puromycin-labeled protein or Akt/70-kDa ribosomal S6 kinase signaling, the indicators of protein synthesis. The expressions of ubiquitinated proteins and muscle RING finger 1 mRNA and protein, markers of the ubiquitin-proteasome system, were increased by hindlimb unloading in WT mice but not in AMPK-DN mice. The expressions of molecules related to the protein degradation system, phosphorylated forkhead box class O3a, inhibitor of κBα, microRNA (miR)-1, and miR-23a, were decreased only in WT mice in response to hindlimb unloading, and 72-kDa heat shock protein expression was higher in AMPK-DN mice than in WT mice. These results imply that AMPK partially regulates unloading-induced atrophy of slow-twitch muscle possibly through modulation of the protein degradation system, especially the ubiquitin-proteasome system.
Collapse
Affiliation(s)
- Tatsuro Egawa
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan
| | - Ayumi Goto
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan; Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Yoshitaka Ohno
- Laboratory of Physiology, School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan
| | - Shingo Yokoyama
- Laboratory of Physiology, School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan
| | - Akihiro Ikuta
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan
| | - Miho Suzuki
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan
| | - Takao Sugiura
- Department of Exercise and Sports Physiology, Faculty of Education, Yamaguchi University, Yamaguchi, Japan
| | - Yoshinobu Ohira
- Graduate School of Health and Sports Science, Doshisha University, Kyotanabe, Kyoto, Japan; and
| | | | - Tatsuya Hayashi
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Katsumasa Goto
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Toyohashi, Aichi, Japan;
| |
Collapse
|
4
|
Eshima H, Poole DC, Kano Y. In vivo Ca2+ buffering capacity and microvascular oxygen pressures following muscle contractions in diabetic rat skeletal muscles: fiber-type specific effects. Am J Physiol Regul Integr Comp Physiol 2015; 309:R128-37. [DOI: 10.1152/ajpregu.00044.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/01/2015] [Indexed: 11/22/2022]
Abstract
In Type 1 diabetes, skeletal muscle resting intracellular Ca2+ concentration ([Ca2+]i) homeostasis is impaired following muscle contractions. It is unclear to what degree this behavior is contingent upon fiber type and muscle oxygenation conditions. We tested the hypotheses that: 1) the rise in resting [Ca2+]i evident in diabetic rat slow-twitch (type I) muscle would be exacerbated in fast-twitch (type II) muscle following contraction; and 2) these elevated [Ca2+]i levels would relate to derangement of microvascular partial pressure of oxygen (PmvO2) rather than sarcoplasmic reticulum dysfunction per se. Adult male Wistar rats were divided randomly into diabetic (DIA: streptozotocin ip) and healthy (CONT) groups. Four weeks later extensor digitorum longus (EDL, predominately type II fibers) and soleus (SOL, predominately type I fibers) muscle contractions were elicited by continuous electrical stimulation (120 s, 100 Hz). Ca2+ imaging was achieved using fura 2-AM in vivo (i.e., circulation intact). DIA increased fatigability in EDL ( P < 0.05) but not SOL. In recovery, SOL [Ca2+]i either returned to its resting baseline within 150 s (CONT 1.00 ± 0.02 at 600 s) or was not elevated in recovery at all (DIA 1.03 ± 0.02 at 600 s, P > 0.05). In recovery, EDL CONT [Ca2+]i also decreased to values not different from baseline (1.06 ± 0.01, P > 0.05) at 600 s. In marked contrast, EDL DIA [Ca2+]i remained elevated for the entire recovery period (i.e., 1.23 ± 0.03 at 600 s, P < 0.05). The inability of [Ca2+]i to return to baseline in EDL DIA was not associated with any reduction of SR Ca2+-ATPase (SERCA) 1 or SERCA2 protein levels (both increased 30–40%, P < 0.05). However, PmvO2 recovery kinetics were markedly slowed in EDL such that mean PmvO2 was substantially depressed (CONT 27.9 ± 2.0 vs. DIA 18.4 ± 2.0 Torr, P < 0.05), and this behavior was associated with the elevated [Ca2+]i. In contrast, this was not the case for SOL ( P > 0.05) in that neither [Ca2+]i nor PmvO2 were deranged in recovery with DIA. In conclusion, recovery of [Ca2+]i homeostasis is impaired in diabetic rat fast-twitch but not slow-twitch muscle in concert with reduced PmvO2 pressures.
Collapse
Affiliation(s)
- Hiroaki Eshima
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Tokyo, Japan; and
| | - David C. Poole
- Departments of Anatomy & Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Tokyo, Japan; and
| |
Collapse
|
5
|
Voluntary Exercise Can Ameliorate Insulin Resistance by Reducing iNOS-Mediated S-Nitrosylation of Akt in the Liver in Obese Rats. PLoS One 2015; 10:e0132029. [PMID: 26172834 PMCID: PMC4501761 DOI: 10.1371/journal.pone.0132029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 06/09/2015] [Indexed: 12/11/2022] Open
Abstract
Voluntary exercise can ameliorate insulin resistance. The underlying mechanism, however, remains to be elucidated. We previously demonstrated that inducible nitric oxide synthase (iNOS) in the liver plays an important role in hepatic insulin resistance in the setting of obesity. In this study, we tried to verify our hypothesis that voluntary exercise improves insulin resistance by reducing the expression of iNOS and subsequent S-nitrosylation of key molecules of glucose metabolism in the liver. Twenty-one Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus, and 18 non-diabetic control Long-Evans Tokushima Otsuka (LETO) rats were randomly assigned to a sedentary group or exercise group subjected to voluntary wheel running for 20 weeks. The voluntary exercise significantly reduced the fasting blood glucose and HOMA-IR in the OLETF rats. In addition, the exercise decreased the amount of iNOS mRNA in the liver in the OLETF rats. Moreover, exercise reduced the levels of S-nitrosylated Akt in the liver, which were increased in the OLETF rats, to those observed in the LETO rats. These findings support our hypothesis that voluntary exercise improves insulin resistance, at least partly, by suppressing the iNOS expression and subsequent S-nitrosylation of Akt, a key molecule of the signal transduction pathways in glucose metabolism in the liver.
Collapse
|
6
|
Sudo M, Ando S, Poole DC, Kano Y. Blood flow restriction prevents muscle damage but not protein synthesis signaling following eccentric contractions. Physiol Rep 2015; 3:3/7/e12449. [PMID: 26149281 PMCID: PMC4552529 DOI: 10.14814/phy2.12449] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
There is a growing body of evidence to suggest that resistance training exercise combined with blood flow restriction (BFR) increases muscle size and strength in humans. Eccentric contraction (ECC) frequently induces severe muscle damage. However, it is not known whether and to what extent muscle damage occurs following ECC + BFR due to the difficulty of conducting definitive invasive studies. The purpose of this study was to examine muscle fiber damage following ECC + BFR at the cellular level. High-intensity ECC was purposefully selected to maximize the opportunity for muscle damage and hypertrophic signaling in our novel in vivo animal model. Male Wistar rats were assigned randomly to the following groups: ECC and ECC + BFR at varying levels of occlusion pressure (140, 160, and 200 Torr). In all conditions, electrical stimulation was applied to the dorsiflexor muscles simultaneously with electromotor-induced plantar flexion. We observed severe histochemical muscle fiber damage (area of damaged fibers/total fiber area analyzed) following ECC (26.4 ± 4.0%). Surprisingly, however, muscle damage was negligible following ECC + BFR140 (2.6 ± 1.2%), ECC+BFR160 (3.0 ± 0.5%), and ECC + BFR200 (0.2 ± 0.1%). Ribosomal S6 kinase 1 (S6K1) phosphorylation, a downstream target of rapamycin (mTOR)-phosphorylation kinase, increased following ECC + BFR200 as well as ECC. In contrast, S6K1 phosphorylation was not altered by BFR alone. The present findings suggest that ECC combined with BFR, even at high exercise intensities, may enhance muscle protein synthesis without appreciable muscle fiber damage.
Collapse
Affiliation(s)
- Mizuki Sudo
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-communications, Chofu Tokyo, Japan Physical Fitness Research Institute Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan
| | - Soichi Ando
- Department of Mechanical Engineering and Intelligent Systems, Control Systems Program, University of Electro-communications, Chofu Tokyo, Japan
| | - David C Poole
- Departments of Anatomy & Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-communications, Chofu Tokyo, Japan
| |
Collapse
|
7
|
Kano Y, Miura S, Eshima H, Ezaki O, Poole DC. The effects of PGC-1α on control of microvascular Po2 kinetics following onset of muscle contractions. J Appl Physiol (1985) 2014; 117:163-70. [DOI: 10.1152/japplphysiol.00080.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
During contractions, regulation of microvascular oxygen partial pressure (Pmvo2), which drives blood-myocyte O2 flux, is a function of skeletal muscle fiber type and oxidative capacity and can be altered by exercise training. The kinetics of Pmvo2 during contractions in predominantly fast-twitch muscles evinces a more rapid fall to far lower levels compared with slow-twitch counterparts. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) improves endurance performance, in part, due to mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. We tested the hypothesis that improvement of exercise capacity by genetic overexpression of PGC-1α would be associated with an altered Pmvo2 kinetics profile of the fast-twitch (white) gastrocnemius during contractions toward that seen in slow-twitch muscles (i.e., slowed response kinetics and elevated steady-state Pmvo2). Phosphorescence quenching techniques were used to measure Pmvo2 at rest and during separate bouts of twitch (1 Hz) and tetanic (100 Hz) contractions in gastrocnemius muscles of mice with overexpression of PGC-1α and wild-type littermates (WT) mice under isoflurane anesthesia. Muscles of PGC-1α mice exhibited less fatigue than WT ( P < 0.01). However, except for the Pmvo2 response immediately following onset of contractions, WT and PGC-1α mice demonstrated similar Pmvo2 kinetics. Specifically, the time delay of the Pmvo2 response was shortened in PGC-1α mice compared with WT (1 Hz: WT, 6.6 ± 2.4 s; PGC-1α, 2.9 ± 0.8 s; 100 Hz: WT, 3.3 ± 1.1 s, PGC-1α, 0.9 ± 0.3 s, both P < 0.05). The ratio of muscle force to Pmvo2 was higher for the duration of tetanic contractions in PGC-1α mice. Slower dynamics and maintenance of higher Pmvo2 following muscle contractions is not obligatory for improved fatigue resistance in fast-twitch muscle of PGC-1α mice. Moreover, overexpression of PGC-1α may accelerate O2 utilization kinetics to a greater extent than O2 delivery kinetics.
Collapse
Affiliation(s)
- Yutaka Kano
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, Japan
| | - Shinji Miura
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Hiroaki Eshima
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, Japan
| | - Osamu Ezaki
- Department of Human Health and Design, Showa Women's University, Tokyo, Japan; and
| | - David C. Poole
- Departments of Anatomy, Physiology, and Kinesiology, Kansas State University, Manhattan, Kansas
| |
Collapse
|
8
|
Barvitenko NN, Aslam M, Filosa J, Matteucci E, Nikinmaa M, Pantaleo A, Saldanha C, Baskurt OK. Tissue oxygen demand in regulation of the behavior of the cells in the vasculature. Microcirculation 2014; 20:484-501. [PMID: 23441854 DOI: 10.1111/micc.12052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/19/2013] [Indexed: 12/20/2022]
Abstract
The control of arteriolar diameters in microvasculature has been in the focus of studies on mechanisms matching oxygen demand and supply at the tissue level. Functionally, important vascular elements include EC, VSMC, and RBC. Integration of these different cell types into functional units aimed at matching tissue oxygen supply with tissue oxygen demand is only achieved when all these cells can respond to the signals of tissue oxygen demand. Many vasoactive agents that serve as signals of tissue oxygen demand have their receptors on all these types of cells (VSMC, EC, and RBC) implying that there can be a coordinated regulation of their behavior by the tissue oxygen demand. Such functions of RBC as oxygen carrying by Hb, rheology, and release of vasoactive agents are considered. Several common extra- and intracellular signaling pathways that link tissue oxygen demand with control of VSMC contractility, EC permeability, and RBC functioning are discussed.
Collapse
|
9
|
Green HJ, Burnett M, Carter S, Jacobs I, Ranney D, Smith I, Tupling S. Role of exercise duration on metabolic adaptations in working muscle to short-term moderate-to-heavy aerobic-based cycle training. Eur J Appl Physiol 2013; 113:1965-78. [PMID: 23543067 DOI: 10.1007/s00421-013-2621-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 02/27/2013] [Indexed: 12/29/2022]
Abstract
This study aimed at investigating the relative roles of the duration versus intensity of exercise on the metabolic adaptations in vastus lateralis to short-term (10 day) aerobic-based cycle training. Healthy males with a peak aerobic power (VO2 peak) of 46.0 ± 2.0 ml kg(-1) min(-1) were assigned to either a 30-min (n = 7) or a 60-min (n = 8) duration performed at two different intensities (with order randomly assigned), namely moderate (M) and heavy (H), corresponding to 70 and 86 % VO2 peak, respectively. No change (P > 0.05) in VO2 peak was observed regardless of the training program. Based on the metabolic responses to prolonged exercise (60 % VO2 peak), both M and H and 30 and 60 min protocols displayed less of a decrease (P < 0.05) in phosphocreatine (PCr) and glycogen (Glyc) and less of an increase (P < 0.05) in free adenosine diphosphate (ADPf), free adenosine monophosphate (AMPf), inosine monophosphate (IMP) and lactate (La). Training for 60 min compared with 30 min resulted in a greater protection (P < 0.05) of ADPf, AMPf, PCr and Glyc during exercise, effects that were not displayed between M and H. The reduction in both VO2 and RER (P < 0.05) observed during submaximal exercise did not depend on training program specifics. These findings indicate that in conjunction with our earlier study (Green et al., Eur J Appl Physiol, 2012b), a threshold exists for duration rather than intensity of aerobic exercise to induce a greater training impact in reducing metabolic strain.
Collapse
Affiliation(s)
- Howard J Green
- Department of Kinesiology, University of Waterloo, Waterloo, ON , N2L3G1, Canada.
| | | | | | | | | | | | | |
Collapse
|
10
|
|
11
|
McDonough P, Padilla DJ, Kano Y, Musch TI, Poole DC, Behnke BJ. Plasticity of microvascular oxygenation control in rat fast-twitch muscle: effects of experimental creatine depletion. Respir Physiol Neurobiol 2012; 181:14-20. [PMID: 22285799 PMCID: PMC3296908 DOI: 10.1016/j.resp.2012.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
Abstract
Aging, heart failure and diabetes each compromise the matching of O2 delivery (Q˙O2)-to-metabolic requirements (O2 uptake, V˙O2) in skeletal muscle such that the O2 pressure driving blood-myocyte O2 flux (microvascular PO2, PmvO2) is reduced and contractile function impaired. In contrast, β-guanidinopropionic acid (β-GPA) treatment improves muscle contractile function, primarily in fast-twitch muscle (Moerland and Kushmerick, 1994). We tested the hypothesis that β-GPA (2% wt/BW in rat chow, 8 weeks; n=14) would improve Q˙O2-to-V˙O2 matching (elevated PmvO2) during contractions (4.5V @ 1Hz) in mixed (MG) and white (WG) portions of the gastrocnemius, both predominantly fast-twitch). Compared with control (CON), during contractions PmvO2 fell less following β-GPA (MG -54%, WG -26%, P<0.05), elevating steady-state PmvO2 (CON, MG: 10±2, WG: 9±1; β-GPA, MG 16±2, WG 18±2 mmHg, P<0.05). This reflected an increased Q˙O2/V˙O2 ratio due primarily to a reduced V˙O2 in β-GPA muscles. It is likely that this adaptation helps facilitate the β-GPA-induced enhancement of contractile function in fast-twitch muscles.
Collapse
Affiliation(s)
- Paul McDonough
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76019, USA
| | | | | | | | | | | |
Collapse
|