1
|
Koirala B, Concas A, Cincotti A, Sun Y, Hernández A, Goodwin ML, Gladden LB, Lai N. Estimation of differential pathlength factor from NIRS measurement in skeletal muscle. Respir Physiol Neurobiol 2024; 326:104283. [PMID: 38788987 DOI: 10.1016/j.resp.2024.104283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/28/2024] [Accepted: 05/19/2024] [Indexed: 05/26/2024]
Abstract
The utilization of continuous wave (CW) near-infrared spectroscopy (NIRS) device to measure non-invasively muscle oxygenation in healthy and disease states is limited by the uncertainties related to the differential path length factor (DPF). DPF value is required to quantify oxygenated and deoxygenated heme groups' concentration changes from measurement of optical densities by NIRS. An integrated approach that combines animal and computational models of oxygen transport and utilization was used to estimate the DPF value in situ. The canine model of muscle oxidative metabolism allowed measurement of both venous oxygen content and tissue oxygenation by CW NIRS under different oxygen delivery conditions. The experimental data obtained from the animal model were integrated in a computational model of O2 transport and utilization and combined with Beer-Lambert law to estimate DPF value in contracting skeletal muscle. A 2.1 value was found for DPF by fitting the mathematical model to the experimental data obtained in contracting muscle (T3) (Med.Sci.Sports.Exerc.48(10):2013-2020,2016). With the estimated value of DPF, model simulations well predicted the optical density measured by NIRS on the same animal model but with different blood flow, arterial oxygen contents and contraction rate (J.Appl.Physiol.108:1169-1176, 2010 and 112:9-19,2013) and demonstrated the robustness of the approach proposed in estimating DPF value. The approach used can overcome the semi-quantitative nature of the NIRS and estimate non-invasively DPF to obtain an accurate concentration change of oxygenated and deoxygenated hemo groups by CW NIRS measurements in contracting skeletal muscle under different oxygen delivery and contraction rate.
Collapse
Affiliation(s)
- B Koirala
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA; Department of Orthopedic Surgery, Washington University, St. Louis, MO, USA
| | - A Concas
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy
| | - A Cincotti
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy
| | - Yi Sun
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai 200241, China; School of Physical Education & Health Care, East China Normal University, Shanghai 200241, China
| | - A Hernández
- Faculty Research Liaison School of Social Sciences, Humanities and Arts University of California, USA
| | - M L Goodwin
- Department of Orthopedic Surgery, Washington University, St. Louis, MO, USA
| | - L B Gladden
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
| | - N Lai
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA; Biomedical Engineering Institute; Old Dominion University, Norfolk, VA, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
| |
Collapse
|
2
|
Menezes TFC, Lee MH, Lucena J, Sperandio PCA, Ota-Arakaki JS, Ferreira EVM, Oliveira RKF. Dyspnea Investigation in Behçet's Disease: The Role of Advanced Diagnostic Methods to Elucidate Dyspnea in Systemic Diseases. Ann Am Thorac Soc 2024; 21:977-982. [PMID: 38819136 PMCID: PMC11160131 DOI: 10.1513/annalsats.202309-790cc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/10/2024] [Indexed: 06/01/2024] Open
Affiliation(s)
- Thais F. C. Menezes
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| | - Michael H. Lee
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California
| | - Juliana Lucena
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| | - Priscila C. A. Sperandio
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| | - Jaquelina S. Ota-Arakaki
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| | - Eloara V. M. Ferreira
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| | - Rudolf K. F. Oliveira
- Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo, São Paulo, Brazil; and
| |
Collapse
|
3
|
Koirala B, Concas A, Sun Y, Gladden LB, Lai N. Relationship between muscle venous blood oxygenation and near-infrared spectroscopy: quantitative analysis of the Hb and Mb contributions. J Appl Physiol (1985) 2023; 134:1063-1074. [PMID: 36927143 PMCID: PMC10125031 DOI: 10.1152/japplphysiol.00406.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 02/22/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
A linear relationship between skeletal muscle venous ([Formula: see text]) and oxygenated (ΔHbMbO2,N) or deoxygenated (ΔHHbMbN) near-infrared spectroscopy (NIRS) signals suggest a main hemoglobin (Hb) contribution to the NIRS signal. However, experimental, and computational evidence supports a significant contribution of myoglobin (Mb) to the NIRS. Venous and NIRS measurements from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48(10):2013-2020, 2016) were integrated into a computational model of muscle O2 transport and utilization to evaluate whether the relationship between venous and NIRS oxygenation can be affected by a significant Mb contribution to the NIRS signals. The mathematical model predicted well the measure of the changes of [Formula: see text] and NIRS signals for different O2 delivery conditions (blood flow, arterial O2 content) in muscle at rest (T1, T2) and during contraction (T3). Furthermore, computational analysis indicates that for adequate O2 delivery, Mb contribution to NIRS signals was significant (20%-30%) even in the presence of a linear [Formula: see text]-NIRS relationship; for a reduced O2 delivery the nonlinearity of the [Formula: see text]-NIRS relationship was related to the Mb contribution (50%). In this case (T3), the deviation from linearity is observed when O2 delivery is reduced from 1.3 to 0.7 L kg-1·min-1 ([Formula: see text] < 10 mLO2 100 mL-1) and Mb saturation decreased from 85% to 40% corresponding to an increase of the Mb contribution to ΔHHbMbN from 15% to 50% and the contribution to ΔHbMbO2,N from 0% to 30%. In contrast to a common assumption, our model indicates that both NIRS signals (ΔHHbMbN and ΔHbMbO2,N are significantly affected by Hb and Mb oxygenation changes.NEW & NOTEWORTHY Within the near-infrared spectroscopy (NIRS) signal, the contribution from hemoglobin is indistinguishable from that of myoglobin. A computation analysis indicates that a linear relationship between muscle venous oxygen content and NIRS signals does not necessarily indicate a negligible myoglobin contribution to the NIRS signal. A reduced oxygen delivery increases the myoglobin contribution to the NIRS signal. The integrative approach proposed is a powerful way to assist in interpreting the elements from which the NIRS signals are derived.
Collapse
Affiliation(s)
- Bhabuk Koirala
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia United States
- Biomedical Engineering Institute, Old Dominion University, Norfolk, Virginia, United States
| | - Alessandro Concas
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy
| | - Yi Sun
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai, China
- School of Physical Education & Health Care, East China Normal University, Shanghai, People's Republic of China
| | - L Bruce Gladden
- School of Kinesiology, Auburn University, Auburn, Alabama United States
| | - Nicola Lai
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia United States
- Biomedical Engineering Institute, Old Dominion University, Norfolk, Virginia, United States
| |
Collapse
|
4
|
Goulding RP, Burnley M, Wüst RCI. How Priming Exercise Affects Oxygen Uptake Kinetics: From Underpinning Mechanisms to Endurance Performance. Sports Med 2023; 53:959-976. [PMID: 37010782 PMCID: PMC10115720 DOI: 10.1007/s40279-023-01832-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/04/2023]
Abstract
The observation that prior heavy or severe-intensity exercise speeds overall oxygen uptake ([Formula: see text]O2) kinetics, termed the "priming effect", has garnered significant research attention and its underpinning mechanisms have been hotly debated. In the first part of this review, the evidence for and against (1) lactic acidosis, (2) increased muscle temperature, (3) O2 delivery, (4) altered motor unit recruitment patterns and (5) enhanced intracellular O2 utilisation in underpinning the priming effect is discussed. Lactic acidosis and increased muscle temperature are most likely not key determinants of the priming effect. Whilst priming increases muscle O2 delivery, many studies have demonstrated that an increased muscle O2 delivery is not a prerequisite for the priming effect. Motor unit recruitment patterns are altered by prior exercise, and these alterations are consistent with some of the observed changes in [Formula: see text]O2 kinetics in humans. Enhancements in intracellular O2 utilisation likely play a central role in mediating the priming effect, probably related to elevated mitochondrial calcium levels and parallel activation of mitochondrial enzymes at the onset of the second bout. In the latter portion of the review, the implications of priming on the parameters of the power-duration relationship are discussed. The effect of priming on subsequent endurance performance depends critically upon which phases of the [Formula: see text]O2 response are altered. A reduced [Formula: see text]O2 slow component or increased fundamental phase amplitude tend to increase the work performable above critical power (i.e. W´), whereas a reduction in the fundamental phase time constant following priming results in an increased critical power.
Collapse
Affiliation(s)
- Richie P Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
| | - Mark Burnley
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Rob C I Wüst
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| |
Collapse
|
5
|
Koirala B, Concas A, Sun Y, Gladden LB, Lai N. Blood volume versus deoxygenated NIRS signal: computational analysis of the effects muscle O 2 delivery and blood volume on the NIRS signals. J Appl Physiol (1985) 2021; 131:1418-1431. [PMID: 34528461 PMCID: PMC8906537 DOI: 10.1152/japplphysiol.00105.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022] Open
Abstract
Near-infrared spectroscopy (NIRS) signals quantify the oxygenated (ΔHbMbO2) and deoxygenated (ΔHHbMb) heme group concentrations. ΔHHbMb has been preferred to ΔHbMbO2 in evaluating skeletal muscle oxygen extraction because it is assumed to be less sensitive to blood volume (BV) changes, but uncertainties exist on this assumption. To analyze this assumption, a computational model of oxygen transport and metabolism is used to quantify the effect of O2 delivery and BV changes on the NIRS signals from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48: 2013-2020, 2016). The computational analysis accounts for microvascular (ΔHbO2, ΔHHb) and extravascular (ΔMbO2, ΔHMb) oxygenated and deoxygenated forms. Simulations predicted muscle oxygen uptake and NIRS signal changes well for blood flows ranging from resting to contracting muscle. Additional NIRS signal simulations were obtained in the absence or presence of BV changes corresponding to a heme groups concentration changes (ΔHbMb = 0-48 µM). Under normal delivery (Q = 1.0 L·kg-1·min-1) in contracting muscle, capillary oxygen saturation (So2) was 62% with capillary ΔHbO2 and ΔHHb of ± 41 µΜ for ΔHbMb = 0. An increase of BV (ΔHbMb = 24 µΜ) caused a ΔHbO2 decrease (16µΜ) almost twice as much as the increase observed for ΔHHb (9 µΜ). When So2 increased to more than 80%, only ΔHbO2 was significantly affected by BV changes. The analysis indicates that microvascular So2 is a key factor in determining the sensitivity of ΔHbMbO2 and deoxygenated ΔHHbMb to BV changes. Contrary to a common assumption, the ΔHHbMb is affected by BV changes in normal contracting muscle and even more in the presence of impaired O2 delivery.NEW & NOTEWORTHY Deoxygenated is preferred to the oxygenated near-infrared spectroscopy signal in evaluating skeletal muscle oxygen extraction because it is assumed to be insensitive to blood volume changes. The quantitative analysis proposed in this study indicates that even in absence of skin blood flow effects, both NIRS signals in presence of either normal or reduced oxygen delivery are affected by blood volume changes. These changes should be considered to properly quantify muscle oxygen extraction by NIRS methods.
Collapse
Affiliation(s)
- B. Koirala
- Department of Electrical and Computer Engineering,
Old Dominion University, Norfolk, Virginia
- Biomedical Engineering Institute, Old
Dominion University, Norfolk, Virginia
| | - A. Concas
- Center for Advanced Studies, Research and
Development in Sardinia (CRS4), Cagliari,
Italy
| | - Yi Sun
- Key Laboratory of Adolescent Health Assessment and
Exercise Intervention of Ministry of Education, East China Normal
University, Shanghai, China
- School of Physical Education & Health Care,
East China Normal University, Shanghai,
China
| | - L. B. Gladden
- School of Kinesiology, Auburn
University, Auburn, Alabama
| | - N. Lai
- Department of Mechanical, Chemical and Materials
Engineering, University of Cagliari, Cagliari,
Italy
- Department of Electrical and Computer Engineering,
Old Dominion University, Norfolk, Virginia
- Biomedical Engineering Institute, Old
Dominion University, Norfolk, Virginia
| |
Collapse
|
6
|
Porcelli S, Rasica L, Ferguson BS, Kavazis AN, McDonald J, Hogan MC, Grassi B, Gladden LB. Effect of acute nitrite infusion on contractile economy and metabolism in isolated skeletal muscle in situ during hypoxia. J Physiol 2021; 598:2371-2384. [PMID: 32537774 DOI: 10.1113/jp279789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 04/14/2020] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS Increased plasma nitrite concentrations may have beneficial effects on skeletal muscle function. The physiological basis explaining these observations has not been clearly defined and it may involve positive effects on muscle contraction force, microvascular O2 delivery and skeletal muscle oxidative metabolism. In the isolated canine gastrocnemius model, we evaluated the effects of acute nitrite infusion on muscle force and skeletal muscle oxidative metabolism. Under hypoxic conditions, but in the presence of normal convective O2 delivery, an elevated plasma nitrite concentration affects neither muscle force, nor muscle contractile economy. In accordance with previous results suggesting limited or no effects of nitrate/nitrite administrations in highly oxidative and highly perfused muscle, our data suggest that neither mitochondrial respiration, nor muscle force generation are affected by acute increased concentrations of NO precursors in hypoxia. ABSTRACT Contrasting findings have been reported concerning the effects of augmented nitric oxide (NO) on skeletal muscle force production and oxygen consumption ( V ̇ O 2 ). The present study examined skeletal muscle mitochondrial respiration and contractile economy in an isolated muscle preparation during hypoxia (but normal convective O2 delivery) with nitrite infusion. Isolated canine gastrocnemius muscles in situ (n = 8) were studied during 3 min of electrically stimulated isometric tetanic contractions corresponding to ∼35% of V ̇ O 2 peak . During contractions, sodium nitrite (NITRITE) or sodium chloride (SALINE) was infused into the popliteal artery. V ̇ O 2 was calculated from the Fick principle. Experiments were carried out in hypoxia ( F I O 2 = 0.12), whereas convective O2 delivery was maintained at normal levels under both conditions by pump-driven blood flow ( Q ̇ ). Muscle biopsies were taken and mitochondrial respiration was evaluated by respirometry. Nitrite infusion significantly increased both nitrite and nitrate concentrations in plasma. No differences in force were observed between conditions. V ̇ O 2 was not significantly different between NITRITE (6.1 ± 1.8 mL 100 g-1 min-1 ) and SALINE (6.2 ± 1.8 mL 100 g-1 min-1 ), even after being 'normalized' per unit of developed force (muscle contractile economy). No differences between conditions were found for maximal ADP-stimulated mitochondrial respiration (both for complex I and complex II), leak respiration and oxidative phosphorylation coupling. In conclusion, in the absence of changes in convective O2 delivery, muscle force, muscle contractile economy and mitochondrial respiration were not affected by acute infusion of nitrite. The previously reported positive effects of elevated plasma nitrite concentrations are presumably mediated by the increased microvascular O2 availability.
Collapse
Affiliation(s)
- Simone Porcelli
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Letizia Rasica
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy.,Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | | | | | - James McDonald
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - Michael C Hogan
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy
| | | |
Collapse
|
7
|
Grassi B, Hogan MC, Gladden LB. Microvascular O2 delivery and O2 utilization during metabolic transitions in skeletal muscle. One-hundred years after the pioneering work by August Krogh. Comp Biochem Physiol A Mol Integr Physiol 2021; 252:110842. [DOI: 10.1016/j.cbpa.2020.110842] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 11/25/2022]
|
8
|
Wakabayashi H, Osawa M, Koga S, Li K, Sakaue H, Sengoku Y, Takagi H. Effects of muscle cooling on kinetics of pulmonary oxygen uptake and muscle deoxygenation at the onset of exercise. Physiol Rep 2019; 6:e13910. [PMID: 30381894 PMCID: PMC6209689 DOI: 10.14814/phy2.13910] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/03/2018] [Indexed: 11/24/2022] Open
Abstract
This study investigated effects of skeletal muscle cooling on the metabolic response and kinetics of pulmonary oxygen uptake (V˙O2) and skeletal muscle deoxygenation during submaximal exercise. In the cooling condition (C), after immersion of the lower body into 12°C water for 30 min, eight healthy males performed 30‐min cycling exercise at the lactate threshold while undergoing thigh cooling by a water‐circulating pad. In the normal condition (N) as control, they conducted the same exercise protocol without cooling. Blood lactate concentration was significantly higher in C than N at 10 min after onset of exercise (4.0 ± 1.7 and 2.4 ± 1.2 mmol/L in C and N, P < 0.05). The percent change in the tissue oxygen saturation of the vastus lateralis, measured by a near‐infrared spectroscopy, was significantly lower in C at 2, 8, 10, and 20 min after the exercise onset compared with N (P < 0.05). The percent change in deoxy hemoglobin+myoglobin concentration (Deoxy[Hb+Mb]) showed a transient peak at the onset of exercise and significantly higher value in C at 10, 20, and 30 min after the exercise onset (P < 0.05). Compared to N, slower V˙O2 kinetics (mean response time) was observed in C (45.6 ± 7.8 and 36.1 ± 7.7 sec in C and N, P < 0.05). The mean response time in C relative to N was significantly correlated with the transient peak of Deoxy[Hb+Mb] in C (r = 0.84, P < 0.05). These results suggest that lower oxygen delivery to the hypothermic skeletal muscle might induce greater glycolytic metabolism during exercise and slower V˙O2 kinetics at the onset of exercise.
Collapse
Affiliation(s)
| | - Mizuki Osawa
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan
| | - Ke Li
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hiroyuki Sakaue
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yasuo Sengoku
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hideki Takagi
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| |
Collapse
|
9
|
Sun YI, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Muscle Near-Infrared Spectroscopy Signals versus Venous Blood Hemoglobin Oxygen Saturation in Skeletal Muscle. Med Sci Sports Exerc 2017; 48:2013-20. [PMID: 27635772 DOI: 10.1249/mss.0000000000001001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The study aimed to examine the relationship between near-infrared spectroscopy (NIRS) signals and venous hemoglobin oxygen saturation (O2Hb%) and venous oxygen concentration (CvO2). METHODS Gastrocnemius muscles (GS) in six dogs were surgically isolated and pump perfused. NIRS signals were recorded, and venous blood samples were collected at constant flow rates (control flow, high flow, and low flow) at rest as well as during electrically stimulated tetanic muscle contractions at rates of one contraction per 2 s (1/2 s) and two contractions per 3 s (2/3 s). Similar data were also collected at three different inspired O2 percentages (12%, 21%, and 100%) with constant blood flow. RESULTS Complete data from five animals were analyzed; all data from one animal were deleted because of erratic oxy-NIRS signals. Venous O2Hb% ranged from 7.6% to 97.5% across the various experimental conditions. After the NIRS signals were normalized to the physiological range, a high linear correlation was seen between the deoxygenated heme signal (HHbMb%) and the venous O2Hb% (R = 0.92 ± 0.05), between the oxygenated heme signal (HbMbO2%) and the venous O2Hb% (R = 0.92 ± 0.03), between the HHbMb% and the CvO2 (R = 0.89 ± 0.06), and between the HbMbO2% and the CvO2 (R = 0.90 ± 0.05). The overall relationships between HHbMb%, HbMbO2%, and venous O2Hb% as well as between HHbMb%, HbMbO2%, and CvO2 were also linear and highly correlated with R values ranging from 0.81 to 0.90. CONCLUSION In this controlled canine muscle model, NIRS signals are highly correlated with venous O2Hb% and CvO2 across a wide range of physiological conditions. The practical application of our results is that for an individual muscle or perhaps muscle group, normalized NIRS HHbMb and HbMbO2 signals accurately reflect the mean venous O2 saturation of the interrogated muscle tissue.
Collapse
Affiliation(s)
- Y I Sun
- 1School of Kinesiology, Auburn University, Auburn, AL; 2Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, CHINA; 3College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL; 4Department of Health and Human Performance, University of Wisconsin-Platteville, Platteville, WI
| | | | | | | | | |
Collapse
|
10
|
Chien JS, Mohammed M, Eldik H, Ibrahim MM, Martinez J, Nichols SP, Wisniewski N, Klitzman B. Injectable Phosphorescence-based Oxygen Biosensors Identify Post Ischemic Reactive Hyperoxia. Sci Rep 2017; 7:8255. [PMID: 28811566 PMCID: PMC5558004 DOI: 10.1038/s41598-017-08490-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 07/11/2017] [Indexed: 11/09/2022] Open
Abstract
Novel injectable biosensors were used to measure interstitial oxygenation before, during, and after transient ischemia. It is well known that reactive hyperemia occurs following a period of ischemia. However, increased blood flow does not necessarily mean increased oxygen tension in the tissue. Therefore, the purpose of this study was to test the hypothesis that tissue reactive hyperoxia occurs following release of hind-limb tourniquet occlusions. Rats were injected with bilateral hind-limb biosensors and were simultaneously subjected to a unilateral femoral vessel ligation. After approximately one and three months, the rats underwent a series of oxygenation challenges, including transient hind-limb tourniquet occlusion. Along with the biosensors, near infrared spectroscopy was used to measure percent oxyhemoglobin in capillaries and laser Doppler flowmetry was used to measure blood flow. Post-occlusion reactive hyperemia was observed. It was accompanied by tissue reactive hyperoxia, affirming that the post-occlusion oxygen supply must have exceeded the expected increased oxygen consumption. The measurement of the physiologic phenomenon of reactive hyperoxia could prove clinically beneficial for both diagnosis and optimizing therapy.
Collapse
Affiliation(s)
- Jennifer S Chien
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mahmoud Mohammed
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA
| | - Hysem Eldik
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mohamed M Ibrahim
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA
| | - Jeremy Martinez
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA
| | - Scott P Nichols
- Profusa, Inc., 345 Allerton Ave, South San Francisco, CA, 94080, USA
| | | | - Bruce Klitzman
- Kenan Plastic Surgery Research Labs and Biomedical Engineering, Duke University Medical Center, Durham, NC, 27710, USA.
| |
Collapse
|
11
|
van der Zwaard S, Jaspers RT, Blokland IJ, Achterberg C, Visser JM, den Uil AR, Hofmijster MJ, Levels K, Noordhof DA, de Haan A, de Koning JJ, van der Laarse WJ, de Ruiter CJ. Oxygenation Threshold Derived from Near-Infrared Spectroscopy: Reliability and Its Relationship with the First Ventilatory Threshold. PLoS One 2016; 11:e0162914. [PMID: 27631607 PMCID: PMC5025121 DOI: 10.1371/journal.pone.0162914] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 08/30/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Near-infrared spectroscopy (NIRS) measurements of oxygenation reflect O2 delivery and utilization in exercising muscle and may improve detection of a critical exercise threshold. PURPOSE First, to detect an oxygenation breakpoint (Δ[O2HbMb-HHbMb]-BP) and compare this breakpoint to ventilatory thresholds during a maximal incremental test across sexes and training status. Second, to assess reproducibility of NIRS signals and exercise thresholds and investigate confounding effects of adipose tissue thickness on NIRS measurements. METHODS Forty subjects (10 trained male cyclists, 10 trained female cyclists, 11 endurance trained males and 9 recreationally trained males) performed maximal incremental cycling exercise to determine Δ[O2HbMb-HHbMb]-BP and ventilatory thresholds (VT1 and VT2). Muscle haemoglobin and myoglobin O2 oxygenation ([HHbMb], [O2HbMb], SmO2) was determined in m. vastus lateralis. Δ[O2HbMb-HHbMb]-BP was determined by double linear regression. Trained cyclists performed the maximal incremental test twice to assess reproducibility. Adipose tissue thickness (ATT) was determined by skinfold measurements. RESULTS Δ[O2HbMb-HHbMb]-BP was not different from VT1, but only moderately related (r = 0.58-0.63, p<0.001). VT1 was different across sexes and training status, whereas Δ[O2HbMb-HHbMb]-BP differed only across sexes. Reproducibility was high for SmO2 (ICC = 0.69-0.97), Δ[O2HbMb-HHbMb]-BP (ICC = 0.80-0.88) and ventilatory thresholds (ICC = 0.96-0.99). SmO2 at peak exercise and at occlusion were strongly related to adipose tissue thickness (r2 = 0.81, p<0.001; r2 = 0.79, p<0.001). Moreover, ATT was related to asymmetric changes in Δ[HHbMb] and Δ[O2HbMb] during incremental exercise (r = -0.64, p<0.001) and during occlusion (r = -0.50, p<0.05). CONCLUSION Although the oxygenation threshold is reproducible and potentially a suitable exercise threshold, VT1 discriminates better across sexes and training status during maximal stepwise incremental exercise. Continuous-wave NIRS measurements are reproducible, but strongly affected by adipose tissue thickness.
Collapse
Affiliation(s)
- Stephan van der Zwaard
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
- * E-mail:
| | - Richard T. Jaspers
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Ilse J. Blokland
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Chantal Achterberg
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Jurrian M. Visser
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Anne R. den Uil
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Mathijs J. Hofmijster
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
- Faculty of Sports and Nutrition, Amsterdam University of Applied Sciences, Amsterdam, the Netherlands
| | - Koen Levels
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Dionne A. Noordhof
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Arnold de Haan
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | - Jos J. de Koning
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| | | | - Cornelis J. de Ruiter
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, the Netherlands
| |
Collapse
|
12
|
Nugent WH, Song BK, Pittman RN, Golub AS. Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle. Microvasc Res 2015; 105:15-22. [PMID: 26683232 DOI: 10.1016/j.mvr.2015.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 01/07/2023]
Abstract
Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues.
Collapse
Affiliation(s)
- William H Nugent
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Bjorn K Song
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Roland N Pittman
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
| | - Aleksander S Golub
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA
| |
Collapse
|
13
|
Wilcox SL, Broxterman RM, Barstow TJ. Constructing quasi-linear V̇O2 responses from nonlinear parameters. J Appl Physiol (1985) 2015; 120:121-9. [PMID: 26565018 DOI: 10.1152/japplphysiol.00507.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/08/2015] [Indexed: 11/22/2022] Open
Abstract
Oxygen uptake (V̇O2) kinetics have been shown to be governed by a nonlinear control system across a range of work rates. However, the linearity of the V̇O2 response to ramp incremental exercise would appear to be the result of a linear control system. This apparent contradiction could represent a balancing of changing V̇O2 kinetics parameter values across a range of work rates. To test this, six healthy men completed bouts of ramp incremental exercise at 15, 30, and 60 W/min (15R, 30R, 60R, respectively) and four bouts of an extended-step incremental exercise. V̇O2 parameter values were derived from the step exercise using two monoexponential models: one starting at time zero and encompassing the entire stage (MONO), and the other truncated to the first 5 min and allowing a time delay (5TD). The resulting parameter values were applied to an integrative model to estimate the ramp responses. As work rate increased, gain values increased (P < 0.001 for MONO and 5TD), as did mean response time (or time constant) values (MONO: P < 0.001; 5TD: P = 0.003). Up to maximal V̇O2 (V̇O(2 max)), the gains of the estimated ramp responses from both models were not different from the gains of the actual observed V̇O2 responses for 15R and 30R (15R: 11.3 ± 1.2, 11.7 ± 0.7, 10.9 ± 0.3; 30R: 10.5 ± 0.8, 11.0 ± 0.5, 10.7 ± 0.3 ml O2·min(-1)·W(-1), for actual, MONO, 5TD, respectively) but were significantly greater for 60R (8.7 ± 1.0, 9.9 ± 0.4, 10.3 ± 0.3 ml O2·min(-1)·W(-1) for actual, MONO, 5TD, respectively). Up to 80%V̇O(2 max) gain values were not significantly different for any ramp rate (P > 0.05 for all). We conclude that the apparent linearity of the V̇O2 response to ramp incremental exercise is consequent to a balancing of increasing time constant and gain parameter values.
Collapse
Affiliation(s)
- Samuel L Wilcox
- Department of Kinesiology, Kansas State University, Manhattan, Kansas; and
| | - Ryan M Broxterman
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Thomas J Barstow
- Department of Kinesiology, Kansas State University, Manhattan, Kansas; and
| |
Collapse
|
14
|
Koga S, Barstow TJ, Okushima D, Rossiter HB, Kondo N, Ohmae E, Poole DC. Validation of a high-power, time-resolved, near-infrared spectroscopy system for measurement of superficial and deep muscle deoxygenation during exercise. J Appl Physiol (1985) 2015; 118:1435-42. [PMID: 25840439 DOI: 10.1152/japplphysiol.01003.2014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/31/2015] [Indexed: 11/22/2022] Open
Abstract
Near-infrared assessment of skeletal muscle is restricted to superficial tissues due to power limitations of spectroscopic systems. We reasoned that understanding of muscle deoxygenation may be improved by simultaneously interrogating deeper tissues. To achieve this, we modified a high-power (∼8 mW), time-resolved, near-infrared spectroscopy system to increase depth penetration. Precision was first validated using a homogenous optical phantom over a range of inter-optode spacings (OS). Coefficients of variation from 10 measurements were minimal (0.5-1.9%) for absorption (μa), reduced scattering, simulated total hemoglobin, and simulated O2 saturation. Second, a dual-layer phantom was constructed to assess depth sensitivity, and the thickness of the superficial layer was varied. With a superficial layer thickness of 1, 2, 3, and 4 cm (μa = 0.149 cm(-1)), the proportional contribution of the deep layer (μa = 0.250 cm(-1)) to total μa was 80.1, 26.9, 3.7, and 0.0%, respectively (at 6-cm OS), validating penetration to ∼3 cm. Implementation of an additional superficial phantom to simulate adipose tissue further reduced depth sensitivity. Finally, superficial and deep muscle spectroscopy was performed in six participants during heavy-intensity cycle exercise. Compared with the superficial rectus femoris, peak deoxygenation of the deep rectus femoris (including the superficial intermedius in some) was not significantly different (deoxyhemoglobin and deoxymyoglobin concentration: 81.3 ± 20.8 vs. 78.3 ± 13.6 μM, P > 0.05), but deoxygenation kinetics were significantly slower (mean response time: 37 ± 10 vs. 65 ± 9 s, P ≤ 0.05). These data validate a high-power, time-resolved, near-infrared spectroscopy system with large OS for measuring the deoxygenation of deep tissues and reveal temporal and spatial disparities in muscle deoxygenation responses to exercise.
Collapse
Affiliation(s)
- Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan;
| | - Thomas J Barstow
- Departments of Anatomy and Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Dai Okushima
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan
| | - Harry B Rossiter
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | | | | | - David C Poole
- Departments of Anatomy and Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| |
Collapse
|
15
|
Adami A, Koga S, Kondo N, Cannon DT, Kowalchuk JM, Amano T, Rossiter HB. Changes in whole tissue heme concentration dissociates muscle deoxygenation from muscle oxygen extraction during passive head-up tilt. J Appl Physiol (1985) 2015; 118:1091-9. [PMID: 25678700 DOI: 10.1152/japplphysiol.00918.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/06/2015] [Indexed: 11/22/2022] Open
Abstract
Skeletal muscle deoxygenated hemoglobin and myoglobin concentration ([HHb]), assessed by near-infrared spectroscopy (NIRS), is commonly used as a surrogate of regional O2 extraction (reflecting the O2 delivery-to-consumption ratio, Q̇/V̇o2). However, [HHb] change (Δ[HHb]) is also influenced by capillary-venous heme concentration, and/or small blood vessel volume (reflected in total heme; [THb]). We tested the hypotheses that Δ[HHb] is associated with O2 extraction, and insensitive to [THb], over a wide range of Q̇/V̇o2 elicited by passive head-up tilt (HUT; 10-min, 15° increments, between -10° and 75°). Steady-state common femoral artery blood flow (FBF) was measured by echo-Doppler, and time-resolved NIRS measured [HHb] and [THb] of vastus lateralis (VL) and gastrocnemius (GS) in 13 men. EMG confirmed muscles were inactive. During HUT in VL [HHb] increased linearly (57 ± 10 to 101 ± 16 μM; P < 0.05 above 15°) and was associated (r(2) ∼ 0.80) with the reduction in FBF (618 ± 75 ml/min at 0° to 268 ± 52 ml/min at 75°; P < 0.05 above 30°) and the increase in [THb] (228 ± 30 vs. 252 ± 32 μM; P < 0.05 above 15°). GS response was qualitatively similar to VL. However, there was wide variation within and among individuals, such that the overall limits of agreement between Δ[HHb] and ΔFBF ranged from -35 to +19% across both muscles. Neither knowledge of tissue O2 saturation nor vascular compliance could appropriately account for the Δ[HHb]-ΔFBF dissociation. Thus, under passive tilt, [HHb] is influenced by Q̇/V̇o2, as well as microvascular hematocrit and/or tissue blood vessel volume, complicating its use as a noninvasive surrogate for muscle microvascular O2 extraction.
Collapse
Affiliation(s)
- Alessandra Adami
- Rehabilitation Clinical Trials Center, Division of Respiratory and Critical Care Physiology and Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | - Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan; and
| | - Daniel T Cannon
- Rehabilitation Clinical Trials Center, Division of Respiratory and Critical Care Physiology and Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | - John M Kowalchuk
- School of Kinesiology and Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Tatsuro Amano
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan; and
| | - Harry B Rossiter
- Rehabilitation Clinical Trials Center, Division of Respiratory and Critical Care Physiology and Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California;
| |
Collapse
|
16
|
Murias JM, Spencer MD, Paterson DH. The critical role of O2 provision in the dynamic adjustment of oxidative phosphorylation. Exerc Sport Sci Rev 2014; 42:4-11. [PMID: 24188979 DOI: 10.1249/jes.0000000000000005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been proposed that the adjustment of oxygen uptake (V˙O2) during the exercise on-transient is controlled intracellularly in young healthy individuals and that insufficient local O2 delivery plays a rate-limiting role in aging and disease only. This review shows that adequate O2 provision to the active tissues is critical in the dynamic adjustment of oxidative phosphorylation even in young healthy individuals.
Collapse
Affiliation(s)
- Juan M Murias
- 1Canadian Centre for Activity and Aging; and 2School of Kinesiology, University of Western Ontario, London, Ontario, Canada
| | | | | |
Collapse
|
17
|
Nyberg M, Christensen PM, Mortensen SP, Hellsten Y, Bangsbo J. Infusion of ATP increases leg oxygen delivery but not oxygen uptake in the initial phase of intense knee-extensor exercise in humans. Exp Physiol 2014; 99:1399-408. [PMID: 25085840 DOI: 10.1113/expphysiol.2014.081141] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present study examined whether an increase in leg blood flow and oxygen delivery at the onset of intense exercise would speed the rate of rise in leg oxygen uptake. Nine healthy men (25 ± 1 years old, mean ± SEM) performed one-leg knee-extensor exercise (62 ± 3 W, 86 ± 3% of incremental test peak power) for 4 min during a control setting (CON) and with infusion of ATP into the femoral artery in order to increase blood flow before and during exercise. In the presence of ATP, femoral arterial blood flow and O2 delivery were higher (P < 0.001) at the onset of exercise and throughout exercise (femoral arterial blood flow after 10 s, 5.1 ± 0.5 versus 2.7 ± 0.3 l min(-1); after 45 s, 6.0 ± 0.5 versus 4.1 ± 0.4 l min(-1); after 90 s, 6.6 ± 0.6 versus 4.5 ± 0.4 l min(-1); and after 240 s, 7.0 ± 0.6 versus 5.1 ± 0.3 l min(-1) in ATP and CON conditions, respectively). Leg oxygen uptake was not different in ATP and CON conditions during the first 20 s of exercise but was lower (P < 0.05) in the ATP compared with CON conditions after 30 s and until the end of exercise (30 s, 436 ± 42 versus 549 ± 45 ml min(-1); and 240 s, 705 ± 31 versus 814 ± 59 ml min(-1) in ATP and CON, respectively). Lactate release was lower after 60, 120 and 180 s of exercise with ATP infusion. These results suggest that O2 delivery is not limiting the rise in skeletal muscle oxygen uptake in the initial phase of intense exercise.
Collapse
Affiliation(s)
- Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter M Christensen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark Team Danmark (Danish elite sport organization), Copenhagen, Denmark
| | - Stefan P Mortensen
- Copenhagen Muscle Research Centre, Copenhagen, Denmark Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
18
|
Wüst RCI, McDonald JR, Sun Y, Ferguson BS, Rogatzki MJ, Spires J, Kowalchuk JM, Gladden LB, Rossiter HB. Slowed muscle oxygen uptake kinetics with raised metabolism are not dependent on blood flow or recruitment dynamics. J Physiol 2014; 592:1857-71. [PMID: 24469073 DOI: 10.1113/jphysiol.2013.267476] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Oxygen uptake kinetics (τVO2) are slowed when exercise is initiated from a raised metabolic rate. Whether this reflects the recruitment of muscle fibres differing in oxidative capacity, or slowed blood flow (Q) kinetics is unclear. This study determined τVO2 in canine muscle in situ, with experimental control over muscle activation and Q during contractions initiated from rest and a raised metabolic rate. The gastrocnemius complex of nine anaesthetised, ventilated dogs was isolated and attached to a force transducer. Isometric tetanic contractions (50 Hz; 200 ms duration) via supramaximal sciatic nerve stimulation were used to manipulate metabolic rate: 3 min stimulation at 0.33 Hz (S1), followed by 3 min at 0.67 Hz (S2). Circulation was initially intact (SPON), and subsequently isolated for pump-perfusion (PUMP) above the greatest value in SPON. Muscle VO2 was determined contraction-by-contraction using an ultrasonic flowmeter and venous oximeter, and normalised to tension-time integral (TTI). τVO2/TTI and τQ were less in S1SPON (mean ± s.d.: 13 ± 3 s and 12 ± 4 s, respectively) than in S2SPON (29 ± 19 s and 31 ± 13 s, respectively; P < 0.05). τVO2/TTI was unchanged by pump-perfusion (S1PUMP, 12 ± 4 s; S2PUMP, 24 ± 6 s; P < 0.001) despite increased O2 delivery; at S2 onset, venous O2 saturation was 21 ± 4% and 65 ± 5% in SPON and PUMP, respectively. VO2 kinetics remained slowed when contractions were initiated from a raised metabolic rate despite uniform muscle stimulation and increased O2 delivery. The intracellular mechanism may relate to a falling energy state, approaching saturating ADP concentration, and/or slowed mitochondrial activation; but further study is required. These data add to the evidence that muscle VO2 control is more complex than previously suggested.
Collapse
Affiliation(s)
- Rob C I Wüst
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 W. Carson Street, CDCRC Building, Torrance, CA 90502, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Bowen TS, Rossiter HB, Benson AP, Amano T, Kondo N, Kowalchuk JM, Koga S. Slowed oxygen uptake kinetics in hypoxia correlate with the transient peak and reduced spatial distribution of absolute skeletal muscle deoxygenation. Exp Physiol 2013; 98:1585-96. [DOI: 10.1113/expphysiol.2013.073270] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
20
|
Spires J, Gladden LB, Grassi B, Goodwin ML, Saidel GM, Lai N. Distinguishing the effects of convective and diffusive O₂ delivery on VO₂ on-kinetics in skeletal muscle contracting at moderate intensity. Am J Physiol Regul Integr Comp Physiol 2013; 305:R512-21. [PMID: 23761640 DOI: 10.1152/ajpregu.00136.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
With current techniques, experimental measurements alone cannot characterize the effects of oxygen blood-tissue diffusion on muscle oxygen uptake (Vo₂) kinetics in contracting skeletal muscle. To complement experimental studies, a computational model is used to quantitatively distinguish the contributions of convective oxygen delivery, diffusion into cells, and oxygen utilization to Vo₂ kinetics. The model is validated using previously published experimental Vo₂ kinetics in response to slowed blood flow (Q) on-kinetics in canine muscle (τQ = 20 s, 46 s, and 64 s) [Goodwin ML, Hernández A, Lai N, Cabrera ME, Gladden LB. J Appl Physiol. 112:9-19, 2012]. Distinctive effects of permeability-surface area or diffusive conductance (PS) and Q on Vo₂ kinetics are investigated. Model simulations quantify the relationship between PS and Q, as well as the effects of diffusion associated with PS and Q dynamics on the mean response time of Vo₂. The model indicates that PS and Q are linearly related and that PS increases more with Q when convective delivery is limited by slower Q dynamics. Simulations predict that neither oxygen convective nor diffusive delivery are limiting Vo₂ kinetics in the isolated canine gastrocnemius preparation under normal spontaneous conditions during transitions from rest to moderate (submaximal) energy demand, although both operate close to the tipping point.
Collapse
Affiliation(s)
- Jessica Spires
- Departments of Biomedical Engineering, Case Western Reserve Univ., Cleveland, OH 44106-7207, USA
| | | | | | | | | | | |
Collapse
|
21
|
Christensen PM, Nyberg M, Mortensen SP, Nielsen JJ, Secher NH, Damsgaard R, Hellsten Y, Bangsbo J. Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery. Am J Physiol Regul Integr Comp Physiol 2013; 305:R313-21. [PMID: 23720134 DOI: 10.1152/ajpregu.00048.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study examined whether a marked reduction in oxygen delivery, unlike findings in moderate-intensity exercise, would slow leg oxygen uptake (Vo2) kinetics during intense exercise (86 ± 3% of incremental test peak power). Seven healthy males (26 ± 1 years, means ± SE) performed one-legged knee-extensor exercise (60 ± 3 W) for 4 min in a control setting (CON) and with arterial infusion of N(G)-monomethyl-l-arginine and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute of exercise were 25-50% lower (P < 0.01) compared with CON (LBF after 10 s: 1.1 ± 0.2 vs. 2.5 ± 0.3 l/min and 45 s: 2.7 ± 0.2 vs. 3.8 ± 0.4 l/min) and 15% lower (P < 0.05) after 2 min of exercise. Leg Vo2 in DB was attenuated (P < 0.05) during the first 2 min of exercise (10 s: 161 ± 26 vs. 288 ± 34 ml/min and 45 s: 459 ± 48 vs. 566 ± 81 ml/min) despite a higher (P < 0.01) oxygen extraction in DB. Net leg lactate release was the same in DB and CON. The present study shows that a marked reduction in oxygen delivery can limit the rise in Vo2 during the initial part of intense exercise. This is in contrast to previous observations during moderate-intensity exercise using the same DB procedure, which suggests that fast-twitch muscle fibers are more sensitive to a reduction in oxygen delivery than slow-twitch fibers.
Collapse
Affiliation(s)
- Peter M Christensen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Wüst RCI, van der Laarse WJ, Rossiter HB. On-off asymmetries in oxygen consumption kinetics of single Xenopus laevis skeletal muscle fibres suggest higher-order control. J Physiol 2012; 591:731-44. [PMID: 23165768 DOI: 10.1113/jphysiol.2012.241992] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The mechanisms controlling skeletal muscle oxygen consumption (V(o)₂) during exercise are not well understood. We determined whether first-order control could explain V(o)₂kinetics at contractions onset (V(o)₂(on)) and cessation (V(o)₂off)) in single skeletal muscle fibres differing in oxdidative capacity, and across stimulation intensities up to V(o)₂(max). Xenopus laevis fibres (n = 21) were suspended in a sealed chamber with a fast response P(o)₂ electrode to measure V(o)₂ every second before, during and after stimulated isometric contractions. A first-order model did not well characterize on-transient V(o)₂ kinetics. Including a time delay (TD) in the model provided a significantly improved characterization than a first-order fit without TD (F-ratio; P < 0.05), and revealed separate 'activation' and 'exponential' phases in 15/21 fibres contracting at V(o)₂(max) (mean ± SD TD: 14 ± 3s). On-transient kinetics (τV(o)₂(on)) was weakly and linearly related to V(o)₂(max) (R² = 0.271, P = 0.015). Off-transient kinetics, however, were first-order, and τV(o)₂(off) was greater in low-oxidative (V(o)₂max < 0.05 nmol mm⁻³s⁻¹ than high-oxidative fibres (V(o)₂(max > 0.10 nmol mm ⁻³ s⁻¹; 170 ± 70 vs. 29 ± 6 s, P < 0.001). 1/ τV(o)₂(off) was proportional to V(o)₂(max) (R² = 0.727, P < 0.001), unlike in the on-transient. The calculated oxygen deficit was larger (P < 0.05) than the post-contraction volume of consumed oxygen at all intensities except V(o)₂(max). These data show a clear dissociation between the kinetic control of V(o)₂at the onset and cessation of contractions and across stimulation intensities. More complex models are therefore required to understand the activation of mitochondrial respiration in skeletal muscle at the start of exercise.
Collapse
Affiliation(s)
- Rob C I Wüst
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | | | | |
Collapse
|
23
|
Christensen PM, Nordsborg NB, Nybo L, Mortensen SP, Sander M, Secher NH, Bangsbo J. Thigh oxygen uptake at the onset of intense exercise is not affected by a reduction in oxygen delivery caused by hypoxia. Am J Physiol Regul Integr Comp Physiol 2012; 303:R843-9. [DOI: 10.1152/ajpregu.00201.2012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In response to hypoxic breathing most studies report slower pulmonary oxygen uptake (V̇o2) kinetics at the onset of exercise, but it is not known if this relates to an actual slowing of the V̇o2 in the active muscles. The aim of the present study was to evaluate whether thigh V̇o2 is slowed at the onset of intense exercise during acute exposure to hypoxia. Six healthy male subjects (25.8 ± 1.4 yr, 79.8 ± 4.0 kg, means ± SE) performed intense (100 ± 6 watts) two-legged knee-extensor exercise for 2 min in normoxia (NOR) and hypoxia [fractional inspired oxygen concentration (FiO2) = 0.13; HYP]. Thigh V̇o2 was measured by frequent arterial and venous blood sampling and blood flow measurements. In arterial blood, oxygen content was reduced ( P < 0.05) from 191 ± 5 ml O2/l in NOR to 180 ± 5 ml O2/l in HYP, and oxygen pressure was reduced ( P < 0.001) from 111 ± 4 mmHg in NOR to 63 ± 4 mmHg in HYP. Thigh blood flow was the same in NOR and HYP, and thigh oxygen delivery was consequently reduced ( P < 0.05) in HYP, but femoral arterial-venous oxygen difference and thigh V̇o2 were similar in NOR and HYP. In addition, muscle lactate release was the same in NOR and HYP, and muscle lactate accumulation during the first 25 s of exercise determined from muscle biopsy sampling was also similar (0.35 ± 0.07 and 0.36 ± 0.07 mmol·kg dry wt−1·s−1 in NOR and HYP). Thus the increase in thigh V̇o2 was not attenuated at the onset of intense knee-extensor exercise despite a reduction in oxygen delivery and pressure.
Collapse
Affiliation(s)
| | | | - Lars Nybo
- Department of Exercise and Sport Sciences, University of Copenhagen, Denmark
| | | | - Mikael Sander
- The Copenhagen Muscle Research Center and Flight Medicine, Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Niels H. Secher
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitaliet, University of Copenhagen, Denmark
| | - Jens Bangsbo
- Department of Exercise and Sport Sciences, University of Copenhagen, Denmark
| |
Collapse
|
24
|
Gandra PG, Nogueira L, Hogan MC. Mitochondrial activation at the onset of contractions in isolated myofibres during successive contractile periods. J Physiol 2012; 590:3597-609. [PMID: 22711953 DOI: 10.1113/jphysiol.2012.232405] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
At the onset of skeletal muscle repetitive contractions, there is a significant delay in the time to achieve oxidative phosphorylation steady state. The purpose of the present study was to examine the factors that limit oxidative phosphorylation at the onset of contractions. NAD(P)H was measured in real time during two contractile periods (2 min each) separated by 5 min of rest in intact single muscle fibres (n = 7) isolated from Xenopus laevis. The fibres were then loaded with the dye tetramethylrhodamine methyl ester perchlorate (TMRM) to evaluate the kinetics of the mitochondrial membrane potential (Δψ (m)) during two further successive contractile periods. At the onset of contractions in the first period, NAD(P)H exhibited a time delay (14.1 ± 1.3 s) before decreasing toward a steady state. In contrast, Δψ(m) decreased immediately after the first contraction and started to be reestablished after 10.7 ± 0.9 s, with restoration to the pre-stimulation values after approximately 32 s. In the second contractile period (5 min after the first), NAD(P)H decreased immediately (i.e. no time delay) after the first contraction and had a significantly shorter time constant compared to the first contractile bout (3.3 ± 0.3 vs. 5.0 ± 0.2 s, P < 0.05). During the second bout, Δψ(m) remained unchanged from pre-stimulation values. These results suggest: (1) that at the onset of contractions, oxidative phosphorylation is primarily limited by the activity of the electron transport chain complexes rather than by a limited level of substrates; and (2) when the muscle is 'primed' by previous contractile activity, the faster enhancement of the cellular respiratory rate is due to intrinsic factors within the myofibre.
Collapse
Affiliation(s)
- Paulo G Gandra
- Department of Medicine-0623, University of California, San Diego, 9500 Gilman Drive La Jolla, CA 92093-0623, USA
| | | | | |
Collapse
|