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Huang Z, Hamblin MR, Zhang Q. Photobiomodulation in experimental models of Alzheimer's disease: state-of-the-art and translational perspectives. Alzheimers Res Ther 2024; 16:114. [PMID: 38773642 PMCID: PMC11106984 DOI: 10.1186/s13195-024-01484-x] [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: 02/07/2024] [Accepted: 05/15/2024] [Indexed: 05/24/2024]
Abstract
Alzheimer's disease (AD) poses a significant public health problem, affecting millions of people across the world. Despite decades of research into therapeutic strategies for AD, effective prevention or treatment for this devastating disorder remains elusive. In this review, we discuss the potential of photobiomodulation (PBM) for preventing and alleviating AD-associated pathologies, with a focus on the biological mechanisms underlying this therapy. Future research directions and guidance for clinical practice for this non-invasive and non-pharmacological therapy are also highlighted. The available evidence indicates that different treatment paradigms, including transcranial and systemic PBM, along with the recently proposed remote PBM, all could be promising for AD. PBM exerts diverse biological effects, such as enhancing mitochondrial function, mitigating the neuroinflammation caused by activated glial cells, increasing cerebral perfusion, improving glymphatic drainage, regulating the gut microbiome, boosting myokine production, and modulating the immune system. We suggest that PBM may serve as a powerful therapeutic intervention for AD.
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Affiliation(s)
- Zhihai Huang
- Department of Neurology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71103, USA
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71103, USA
| | - Michael R Hamblin
- Laser Research Centre, University of Johannesburg, Doornfontein, 2028, South Africa.
| | - Quanguang Zhang
- Department of Neurology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71103, USA.
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71103, USA.
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Highton D, Caldwell M, Tachtsidis I, Elwell CE, Smith M, Cooper CE. The influence of carbon dioxide on cerebral metabolism and oxygen consumption: combining multimodal monitoring with dynamic systems modelling. Biol Open 2024; 13:bio060087. [PMID: 38180242 PMCID: PMC10810564 DOI: 10.1242/bio.060087] [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: 07/24/2023] [Accepted: 11/22/2023] [Indexed: 01/06/2024] Open
Abstract
Hypercapnia increases cerebral blood flow. The effects on cerebral metabolism remain incompletely understood although studies show an oxidation of cytochrome c oxidase, Complex IV of the mitochondrial respiratory chain. Systems modelling was combined with previously published non-invasive measurements of cerebral tissue oxygenation, cerebral blood flow, and cytochrome c oxidase redox state to evaluate any metabolic effects of hypercapnia. Cerebral tissue oxygen saturation and cytochrome oxidase redox state were measured with broadband near infrared spectroscopy and cerebral blood flow velocity with transcranial Doppler ultrasound. Data collected during 5-min hypercapnia in awake human volunteers were analysed using a Fick model to determine changes in brain oxygen consumption and a mathematical model of cerebral hemodynamics and metabolism (BrainSignals) to inform on mechanisms. Either a decrease in metabolic substrate supply or an increase in metabolic demand modelled the cytochrome oxidation in hypercapnia. However, only the decrease in substrate supply explained both the enzyme redox state changes and the Fick-calculated drop in brain oxygen consumption. These modelled outputs are consistent with previous reports of CO2 inhibition of mitochondrial succinate dehydrogenase and isocitrate dehydrogenase. Hypercapnia may have physiologically significant effects suppressing oxidative metabolism in humans and perturbing mitochondrial signalling pathways in health and disease.
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Affiliation(s)
- David Highton
- Neurocritical Care Unit, University College London Hospitals, National Hospital for Neurology & Neurosurgery, London WC1N 3BG, UK
- Princess Alexandra Hospital Southside Clinical Unit, University of Queensland, Brisbane QLD 4102, Australia
| | - Matthew Caldwell
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Clare E. Elwell
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Martin Smith
- Neurocritical Care Unit, University College London Hospitals, National Hospital for Neurology & Neurosurgery, London WC1N 3BG, UK
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, London WC1E 6BT, UK
| | - Chris E. Cooper
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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Leadley G, Austin T, Bale G. Review of measurements and imaging of cytochrome-c-oxidase in humans using near-infrared spectroscopy: an update. BIOMEDICAL OPTICS EXPRESS 2024; 15:162-184. [PMID: 38223181 PMCID: PMC10783912 DOI: 10.1364/boe.501915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/21/2023] [Indexed: 01/16/2024]
Abstract
This review examines advancements in the measurement and imaging of oxidized cytochrome-c-oxidase (oxCCO) using near-infrared spectroscopy (NIRS) in humans since 2016. A total of 34 published papers were identified, with a focus on both adult and neonate populations. The NIRS-derived oxCCO signal has been demonstrated to correlate with physiological parameters and hemodynamics. New instrumentation, such as systems that allow the imaging of changes of oxCCO with diffuse optical tomography or combine the oxCCO measurement with diffuse correlation spectroscopy measures of blood flow, have advanced the field in the past decade. However, variability in its response across different populations and paradigms and lack of standardization limit its potential as a reliable and valuable indicator of brain health. Future studies should address these issues to fulfill the vision of oxCCO as a clinical biomarker.
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Affiliation(s)
- Georgina Leadley
- Department of Paediatrics, University of Cambridge, UK
- Department of Engineering, University of Cambridge, UK
- Department of Medical Physics and Biomedical Engineering, UCL, UK
| | - Topun Austin
- Department of Paediatrics, University of Cambridge, UK
| | - Gemma Bale
- Department of Engineering, University of Cambridge, UK
- Department of Physics, University of Cambridge, UK
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Suwalski M, Shoemaker LN, Shoemaker JK, Diop M, Murkin JM, Chui J, St. Lawrence K, Milej D. Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain. Metabolites 2022; 12:metabo12090817. [PMID: 36144221 PMCID: PMC9502461 DOI: 10.3390/metabo12090817] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are frequently used during vascular and cardiac surgeries as a non-invasive means of assessing brain health; however, signal contamination from extracerebral tissues remains a concern. As an alternative, hyperspectral (hs)NIRS can be used to measure changes in the oxidation state of cytochrome c oxidase (ΔoxCCO), which provides greater sensitivity to the brain given its higher mitochondrial concentration versus the scalp. The purpose of this study was to evaluate the depth sensitivity of the oxCCO signal to changes occurring in the brain and extracerebral tissue components. The oxCCO assessment was conducted using multi-distance hsNIRS (source-detector separations = 1 and 3 cm), and metabolic changes were compared to changes in StO2. Ten participants were monitored using an in-house system combining hsNIRS and diffuse correlation spectroscopy (DCS). Data were acquired during carotid compression (CC) to reduce blood flow and hypercapnia to increase flow. Reducing blood flow by CC resulted in a significant decrease in oxCCO measured at rSD = 3 cm but not at 1 cm. In contrast, significant changes in StO2 were found at both distances. Hypercapnia caused significant increases in StO2 and oxCCO at rSD = 3 cm, but not at 1 cm. Extracerebral contamination resulted in elevated StO2 but not oxCCO after hypercapnia, which was significantly reduced by applying regression analysis. This study demonstrated that oxCCO was less sensitive to extracerebral signals than StO2.
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Affiliation(s)
- Marianne Suwalski
- Department of Medical Biophysics, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
- Imaging Division, Lawson Health Research Institute, Imaging Program, 268 Grosvenor St, London, ON N6A 4V2, Canada
- Correspondence: (M.S.); (D.M.)
| | - Leena N. Shoemaker
- Imaging Division, Lawson Health Research Institute, Imaging Program, 268 Grosvenor St, London, ON N6A 4V2, Canada
- Department of Kinesiology, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - J. Kevin Shoemaker
- Department of Kinesiology, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - Mamadou Diop
- Department of Medical Biophysics, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
- Imaging Division, Lawson Health Research Institute, Imaging Program, 268 Grosvenor St, London, ON N6A 4V2, Canada
| | - John M. Murkin
- Department of Anesthesiology and Perioperative Medicine, London Health Science Centre, 339 Windermere Rd, London, ON N6A 5A5, Canada
| | - Jason Chui
- Department of Anesthesiology and Perioperative Medicine, London Health Science Centre, 339 Windermere Rd, London, ON N6A 5A5, Canada
| | - Keith St. Lawrence
- Department of Medical Biophysics, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
- Imaging Division, Lawson Health Research Institute, Imaging Program, 268 Grosvenor St, London, ON N6A 4V2, Canada
| | - Daniel Milej
- Department of Medical Biophysics, Western University, 1151 Richmond St, London, ON N6A 3K7, Canada
- Imaging Division, Lawson Health Research Institute, Imaging Program, 268 Grosvenor St, London, ON N6A 4V2, Canada
- Correspondence: (M.S.); (D.M.)
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Milej D, Rajaram A, Suwalski M, Morrison LB, Shoemaker LN, St. Lawrence K. Assessing the relationship between the cerebral metabolic rate of oxygen and the oxidation state of cytochrome-c-oxidase. NEUROPHOTONICS 2022; 9:035001. [PMID: 35874144 PMCID: PMC9298853 DOI: 10.1117/1.nph.9.3.035001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/22/2022] [Indexed: 05/07/2023]
Abstract
Significance: Hyperspectral near-infrared spectroscopy (hsNIRS) combined with diffuse correlation spectroscopy (DCS) provides a noninvasive approach for monitoring cerebral blood flow (CBF), the cerebral metabolic rate of oxygen ( CMRO 2 ) and the oxidation state of cytochrome-c-oxidase (oxCCO). CMRO 2 is calculated by combining tissue oxygen saturation ( S t O 2 ) with CBF, whereas oxCCO can be measured directly by hsNIRS. Although both reflect oxygen metabolism, a direct comparison has yet to be studied. Aim: We aim to investigate the relationship between CMRO 2 and oxCCO during periods of restricted oxygen delivery and lower metabolic demand. Approach: A hybrid hsNIRS/DCS system was used to measure hemodynamic and metabolic responses in piglets exposed to cerebral ischemia and anesthetic-induced reductions in brain activity. Results: Although a linear relationship was observed between CMRO 2 and oxCCO during ischemia, both exhibited a nonlinear relationship with respect to CBF. In contrast, linear correlation was sufficient to characterize the relationships between CMRO 2 and CBF and between the two metabolic markers during reduced metabolic demand. Conclusions: The observed relationship between CMRO 2 and oxCCO during periods of restricted oxygen delivery and lower metabolic demand indicates that the two metabolic markers are strongly correlated.
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Affiliation(s)
- Daniel Milej
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
- Address all correspondence to Daniel Milej,
| | - Ajay Rajaram
- Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Marianne Suwalski
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Laura B. Morrison
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
| | - Leena N. Shoemaker
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
- Western University, Department of Kinesiology, London, Ontario, Canada
| | - Keith St. Lawrence
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
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Hashem M, Wu Y, Dunn JF. Quantification of cytochrome c oxidase and tissue oxygenation using CW-NIRS in a mouse cerebral cortex. BIOMEDICAL OPTICS EXPRESS 2021; 12:7632-7656. [PMID: 35003857 PMCID: PMC8713667 DOI: 10.1364/boe.435532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/06/2021] [Accepted: 11/05/2021] [Indexed: 05/05/2023]
Abstract
We provide a protocol for measuring the absolute concentration of the oxidized and reduced state of cytochrome c oxidase (CCO) in the cerebral cortex of mice, using broadband continuous-wave NIRS. The algorithm (NIR-AQUA) allows for absolute quantification of CCO and deoxyhemoglobin. Combined with an anoxia pulse, this also allows for quantification of total hemoglobin, and tissue oxygen saturation. CCO in the cortex was 4.9 ± 0.1 μM (mean ± SD, n=6). In normoxia, 84% of CCO was oxidized. We include hypoxia and cyanide validation studies to show CCO can be quantified independently to hemoglobin. This can be applied to study oxidative metabolism in the many rodent models of neurological disease.
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Affiliation(s)
- Mada Hashem
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
| | - Ying Wu
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
| | - Jeff F. Dunn
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
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Thiele RH, Ikeda K, Osuru HP, Zuo Z. Comparison of Broadband and Discrete Wavelength Near-Infrared Spectroscopy Algorithms for the Detection of Cytochrome aa3 Reduction. Anesth Analg 2020; 129:1273-1280. [PMID: 29916864 DOI: 10.1213/ane.0000000000003572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Cytochrome aa3, the terminal component of the electron transport chain, absorbs near-infrared radiation (NIR) differentially depending on its oxidation state (Cytox), which can in theory be measured using near-infrared spectroscopy (NIRS) by relating light absorption at specific wavelengths to chromophore concentrations. Some NIRS algorithms use discrete wavelengths, while others analyze a band of NIR (broadband NIRS). The purpose of this study was to test the ability of discrete wavelength and broadband algorithms to measure changes in Cytox (primary outcome), and to determine whether or not a discreet wavelength NIRS algorithm could perform similarly to a broadband NIRS algorithm for the measurement of Cytox in a staged hypoxia-cyanide model (hypoxia and cyanide have oppositional effects on tissue saturation, but both cause cytochrome reduction). METHODS Twenty Sprague-Dawley rats were anesthetized with isoflurane, intubated, and instrumented. Blood pressure, end-tidal carbon dioxide, and arterial oxygen saturation were measured. A halogen light source transmitted NIR transcranially. NIR from the light source and the skull was transmitted to 2 cooled charge-coupled device spectrometers. Rats were subjected to anoxia (fraction of inspired oxygen, 0.0) until arterial oxygen saturation decreased to 70%. After recovery, 5 mg/kg sodium cyanide was injected intravenously. The cycle was repeated until cardiac arrest occurred. Relative concentrations of hemoglobin and cytochrome aa3 were calculated using discreet wavelength and broadband NIRS algorithms. RESULTS Hypoxia led to an increase in calculated deoxyhemoglobin (0.20 arbitrary units [AUs]; 95% confidence interval [CI], 0.17-0.22; P < .0001), a decrease in calculated oxyhemoglobin (-0.16 AUs; 95% CI, -0.19 to -0.14; P < .0001), and a decrease in calculated Cytox (-0.057 AUs; 95% CI, -0.073 to 0.0040; P < .001). Cyanide led to a decrease in calculated deoxyhemoglobin (-0.037 AUs; 95% CI, 0.046 to -0.029; P < .001), an increase in calculated oxyhemoglobin (0.053 AUs; 95% CI, 0.040-0.065; P < .001), and a decrease in calculated Cytox (-0.056 AUs; 95% CI, -0.064 to -0.048; P < .001). The correlations between "discreet" wavelength algorithms (using 4, 6, 8, and 10 wavelengths) and the broadband algorithm for the measurement of calculated Cytox were 0.54 (95% CI, 0.52-0.56), 0.87 (0.87-0.88), 0.88 (0.88-0.89), and 0.95 (0.95-0.95), respectively. CONCLUSIONS The broadband and 10 wavelength algorithm were able to accurately track changes in Cytox for all experiments.
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Affiliation(s)
- Robert H Thiele
- From the Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, Virginia
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Giannoni L, Lange F, Tachtsidis I. Investigation of the quantification of hemoglobin and cytochrome-c-oxidase in the exposed cortex with near-infrared hyperspectral imaging: a simulation study. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-25. [PMID: 32239847 PMCID: PMC7109387 DOI: 10.1117/1.jbo.25.4.046001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 03/12/2020] [Indexed: 05/04/2023]
Abstract
SIGNIFICANCE We present a Monte Carlo (MC) computational framework that simulates near-infrared (NIR) hyperspectral imaging (HSI) aimed at assisting quantification of the in vivo hemodynamic and metabolic states of the exposed cerebral cortex in small animal experiments. This can be done by targeting the NIR spectral signatures of oxygenated (HbO2) and deoxygenated (HHb) hemoglobin for hemodynamics as well as the oxidative state of cytochrome-c-oxidase (oxCCO) for measuring tissue metabolism. AIM The aim of this work is to investigate the performances of HSI for this specific application as well as to assess key factors for the future design and operation of a benchtop system. APPROACH The MC framework, based on Mesh-based Monte Carlo (MMC), reproduces a section of the exposed cortex of a mouse from an in vivo image and replicates hyperspectral illumination and detection at multiple NIR wavelengths (up to 121). RESULTS The results demonstrate: (1) the fitness of the MC framework to correctly simulate hyperspectral data acquisition; (2) the capability of HSI to reconstruct spatial changes in the concentrations of HbO2, HHb, and oxCCO during a simulated hypoxic condition; (3) that eight optimally selected wavelengths between 780 and 900 nm provide minimal differences in the accuracy of the hyperspectral results, compared to the "gold standard" of 121 wavelengths; and (4) the possibility to mitigate partial pathlength effects in the reconstructed data and to enhance quantification of the hemodynamic and metabolic responses. CONCLUSIONS The MC framework is proved to be a flexible and useful tool for simulating HSI also for different applications and targets.
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Affiliation(s)
- Luca Giannoni
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- Address all correspondence to Luca Giannoni, E-mail:
| | - Frédéric Lange
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Ilias Tachtsidis
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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Kaynezhad P, Mitra S, Bale G, Bauer C, Lingam I, Meehan C, Avdic-Belltheus A, Martinello KA, Bainbridge A, Robertson NJ, Tachtsidis I. Quantification of the severity of hypoxic-ischemic brain injury in a neonatal preclinical model using measurements of cytochrome-c-oxidase from a miniature broadband-near-infrared spectroscopy system. NEUROPHOTONICS 2019; 6:045009. [PMID: 31737744 PMCID: PMC6855218 DOI: 10.1117/1.nph.6.4.045009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/14/2019] [Indexed: 05/05/2023]
Abstract
We describe the development of a miniaturized broadband near-infrared spectroscopy system (bNIRS), which measures changes in cerebral tissue oxyhemoglobin ( [ HbO 2 ] ) and deoxyhemoglobin ([HHb]) plus tissue metabolism via changes in the oxidation state of cytochrome-c-oxidase ([oxCCO]). The system is based on a small light source and a customized mini-spectrometer. We assessed the instrument in a preclinical study in 27 newborn piglets undergoing transient cerebral hypoxia-ischemia (HI). We aimed to quantify the recovery of the HI insult and estimate the severity of the injury. The recovery in brain oxygenation ( Δ [ HbDiff ] = Δ [ HbO 2 ] - Δ [ HHb ] ), blood volume ( Δ [ HbT ] = Δ [ HbO 2 ] + Δ [ HHb ] ), and metabolism ( Δ [ oxCCO ] ) for up to 30 min after the end of HI were quantified in percentages using the recovery fraction (RF) algorithm, which quantifies the recovery of a signal with respect to baseline. The receiver operating characteristic analysis was performed on bNIRS-RF measurements compared to proton ( H 1 ) magnetic resonance spectroscopic (MRS)-derived thalamic lactate/N-acetylaspartate (Lac/NAA) measured at 24-h post HI insult; Lac/NAA peak area ratio is an accurate surrogate marker of neurodevelopmental outcome in babies with neonatal HI encephalopathy. The Δ [ oxCCO ] -RF cut-off threshold of 79% within 30 min of HI predicted injury severity based on Lac/NAA with high sensitivity (100%) and specificity (93%). A significant difference in thalamic Lac/NAA was noticed ( p < 0.0001 ) between the two groups based on this cut-off threshold of 79% Δ [ oxCCO ] -RF. The severe injury group ( n = 13 ) had ∼ 30 % smaller recovery in Δ [ HbDiff ] -RF ( p = 0.0001 ) and no significant difference was observed in Δ [ HbT ] -RF between groups. At 48 h post HI, significantly higher P 31 -MRS-measured inorganic phosphate/exchangeable phosphate pool (epp) ( p = 0.01 ) and reduced phosphocreatine/epp ( p = 0.003 ) were observed in the severe injury group indicating persistent cerebral energy depletion. Based on these results, the bNIRS measurement of the oxCCO recovery fraction offers a noninvasive real-time biomarker of brain injury severity within 30 min following HI insult.
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Affiliation(s)
- Pardis Kaynezhad
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- Address all correspondence to Ilias Tachtsidis, E-mail:
| | - Subhabrata Mitra
- University College London, Institute for Women’s Health, London, United Kingdom
| | - Gemma Bale
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Cornelius Bauer
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Ingran Lingam
- University College London, Institute for Women’s Health, London, United Kingdom
| | - Christopher Meehan
- University College London, Institute for Women’s Health, London, United Kingdom
| | | | | | - Alan Bainbridge
- University College London Hospital, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Nicola J. Robertson
- University College London, Institute for Women’s Health, London, United Kingdom
| | - Ilias Tachtsidis
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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Abstract
Next to cancer, Alzheimer's disease (AD) and dementia is probably the most worrying health problem facing the Western world today. A large number of clinical trials have failed to show any benefit of the tested drugs in stabilizing or reversing the steady decline in cognitive function that is suffered by dementia patients. Although the pathological features of AD consisting of beta-amyloid plaques and tau tangles are well established, considerable debate exists concerning the genetic or lifestyle factors that predispose individuals to developing dementia. Photobiomodulation (PBM) describes the therapeutic use of red or near-infrared light to stimulate healing, relieve pain and inflammation, and prevent tissue from dying. In recent years PBM has been applied for a diverse range of brain disorders, frequently applied in a non-invasive manner by shining light on the head (transcranial PBM). The present review discusses the mechanisms of action of tPBM in the brain, and summarizes studies that have used tPBM to treat animal models of AD. The results of a limited number of clinical trials that have used tPBM to treat patients with AD and dementia are discussed.
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Affiliation(s)
- Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
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11
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Nosrati R, Lin S, Mohindra R, Ramadeen A, Toronov V, Dorian P. Study of the Effects of Epinephrine on Cerebral Oxygenation and Metabolism During Cardiac Arrest and Resuscitation by Hyperspectral Near-Infrared Spectroscopy. Crit Care Med 2019; 47:e349-e357. [PMID: 30747772 DOI: 10.1097/ccm.0000000000003640] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Epinephrine is routinely administered to sudden cardiac arrest patients during resuscitation, but the neurologic effects on patients treated with epinephrine are not well understood. This study aims to assess the cerebral oxygenation and metabolism during ventricular fibrillation cardiac arrest, cardiopulmonary resuscitation, and epinephrine administration. DESIGN To investigate the effects of equal dosages of IV epinephrine administrated following sudden cardiac arrest as a continuous infusion or successive boluses during cardiopulmonary resuscitation, we monitored cerebral oxygenation and metabolism using hyperspectral near-infrared spectroscopy. SETTINGS A randomized laboratory animal study. SUBJECTS Nine healthy pigs. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Our study showed that although continuous epinephrine administration had no significant impact on overall cerebral hemodynamics, epinephrine boluses transiently improved cerebral oxygenation (oxygenated hemoglobin) and metabolism (cytochrome c oxidase) by 15% ± 6.7% and 49% ± 18%, respectively (p < 0.05) compared with the baseline (untreated) ventricular fibrillation. Our results suggest that the effects of epinephrine diminish with successive boluses as the impact of the third bolus on brain oxygen metabolism was 24.6% ± 3.8% less than that of the first two boluses. CONCLUSIONS Epinephrine administration by bolus resulted in transient improvements in cerebral oxygenation and metabolism, whereas continuous epinephrine infusion did not, compared with placebo. Future studies are needed to evaluate and optimize the use of epinephrine in cardiac arrest resuscitation, particularly the dose, timing, and mode of administration.
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Affiliation(s)
- Reyhaneh Nosrati
- Department of Physics, Ryerson University, Toronto, ON, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Steve Lin
- Department of Physics, Ryerson University, Toronto, ON, Canada
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
| | - Rohit Mohindra
- Jewish General Hospital Department of Emergency Medicine, 3755 Ch de la Côte-Sainte-Catherine, Montreal, QC, Canada
- Department of Critical Care Research, McGill University, Montreal, QC, Canada
| | - Andrew Ramadeen
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | | | - Paul Dorian
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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Nguyen TN, Wu W, Woldermichael E, Toronov V, Lin S. Hyperspectral near-infrared spectroscopy assessment of the brain during hypoperfusion. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-6. [PMID: 30877717 PMCID: PMC6975180 DOI: 10.1117/1.jbo.24.3.035007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/23/2019] [Indexed: 05/10/2023]
Abstract
Two-thirds of out-of-hospital cardiac arrest patients, who survive to hospital admission, die in the hospital from neurological injuries related to cerebral hypoperfusion. Therefore, noninvasive real-time monitoring of the cerebral oxygen metabolism in cardiac arrest patients is extremely important. Hyperspectral near-infrared spectroscopy (hNIRS) is a noninvasive technique that measures concentrations of the key chromophores in the brain, such as oxygenated hemoglobin, deoxygenated hemoglobin, and cytochrome C oxidase (CCO), an intracellular marker of oxygen consumption. We tested hNIRS on 10 patients undergoing transcatheter aortic valve insertion, where rapid ventricular pacing (RVP) is required to temporarily induce sudden hypotension and hypoperfusion that mimic cardiac arrest. Using multidistance hNIRS, we found that tissue oxygen saturation changes in the cerebral tissue were lower than those in the scalp during RVP. CCO redox changes were detected in cerebral tissue but not in the scalp during RVP. We have demonstrated that hNIRS is feasible and can detect sudden changes in cerebral oxygenation and metabolism in patients during profound hypotension.
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Affiliation(s)
- Thu Nga Nguyen
- Ryerson University, Faculty of Science, Department of Physics, Toronto, Ontario, Canada
- Address all correspondence to Thu Nga Nguyen, E-mail:
| | - Wen Wu
- St. Michael’s Hospital, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
- University of Toronto, Department of Medicine, Toronto, Ontario, Canada
| | - Ermias Woldermichael
- Ryerson University, Faculty of Science, Department of Physics, Toronto, Ontario, Canada
| | - Vladislav Toronov
- Ryerson University, Faculty of Science, Department of Physics, Toronto, Ontario, Canada
- Institute for Biomedical Engineering, Science and Technology, Toronto, Ontario, Canada
| | - Steve Lin
- St. Michael’s Hospital, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
- University of Toronto, Department of Medicine, Toronto, Ontario, Canada
- Institute for Biomedical Engineering, Science and Technology, Toronto, Ontario, Canada
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Lee J, Rockwood G, Logue B, Manandhar E, Petrikovics I, Han C, Bebarta V, Mahon SB, Burney T, Brenner M. Monitoring Dose Response of Cyanide Antidote Dimethyl Trisulfide in Rabbits Using Diffuse Optical Spectroscopy. J Med Toxicol 2018; 14:295-305. [PMID: 30094773 DOI: 10.1007/s13181-018-0680-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 07/17/2018] [Accepted: 07/23/2018] [Indexed: 01/22/2023] Open
Abstract
INTRODUCTION Cyanide (CN) poisoning is a serious chemical threat from accidental or intentional exposures. Current CN exposure treatments, including direct binding agents, methemoglobin donors, and sulfur donors, have several limitations. Dimethyl trisulfide (DMTS) is capable of reacting with CN to form the less toxic thiocyanate with high efficiency, even without the sulfurtransferase rhodanese. We investigated a soluble DMTS formulation with the potential to provide a continuous supply of substrate for CN detoxification which could be delivered via intramuscular (IM) injection in a mass casualty situation. We also used non-invasive technology, diffuse optical spectroscopy (DOS), to monitor physiologic changes associated with CN exposure and reversal. METHODS Thirty-six New Zealand white rabbits were infused with a lethal dose of sodium cyanide solution (20 mg/60 ml normal saline). Animals were divided into three groups and treated with saline, low dose (20 mg), or high dose (150 mg) of DMTS intramuscularly. DOS continuously assessed changes in tissue hemoglobin concentrations and cytochrome c oxidase redox state status throughout the experiment. RESULTS IM injection of DMTS increased the survival in lethal CN poisoning. DOS demonstrated that high-dose DMTS (150 mg) reversed the effects of CN exposure on cytochrome c oxidase, while low dose (20 mg) did not fully reverse effects, even in surviving animals. CONCLUSIONS This study demonstrated potential efficacy for the novel approach of supplying substrate for non-rhodanese mediated sulfur transferase pathways for CN detoxification via intramuscular injection in a moderate size animal model and showed that DOS was useful for optimizing the DMTS treatment.
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Affiliation(s)
- Jangwoen Lee
- Beckman Laser Institute, University of California, 1002 Health Sciences Rd. East, Irvine, CA, 92612, USA.
| | - Gary Rockwood
- Analytical Toxicology Division, US Army Medical Research Institute of Chemical Defense, 2900 Rickets Point Road, Aberdeen Proving Ground, Aberdeen, MD, 21010, USA
| | - Brian Logue
- Department of Chemistry and Biochemistry, South Dakota University, Brookings, SD, 57007, USA
| | - Erica Manandhar
- Department of Chemistry and Biochemistry, South Dakota University, Brookings, SD, 57007, USA
| | - Ilona Petrikovics
- Department of Chemistry, Sam Houston State University, Huntsville, TX, 77341, USA
| | - Changhoon Han
- Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang-si, Geonggi-do, 10444, South Korea
| | - Vik Bebarta
- Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Sari B Mahon
- Beckman Laser Institute, University of California, 1002 Health Sciences Rd. East, Irvine, CA, 92612, USA
| | - Tanya Burney
- Beckman Laser Institute, University of California, 1002 Health Sciences Rd. East, Irvine, CA, 92612, USA
| | - Matthew Brenner
- Beckman Laser Institute, University of California, 1002 Health Sciences Rd. East, Irvine, CA, 92612, USA
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, Irvine, CA, 92868, USA
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Ghosh A, Highton D, Kolyva C, Tachtsidis I, Elwell CE, Smith M. Hyperoxia results in increased aerobic metabolism following acute brain injury. J Cereb Blood Flow Metab 2017; 37:2910-2920. [PMID: 27837190 PMCID: PMC5536254 DOI: 10.1177/0271678x16679171] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24-72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy. Increased inspired oxygen resulted in increased pbrO2 [ΔpbrO2 30.9 mmHg p < 0.001], reduced LPR [ΔLPR -3.07 p = 0.015], and increased cytochrome c oxidase (CCO) oxidation (Δ[oxCCO] + 0.32 µM p < 0.001) which persisted on return-to-baseline (Δ[oxCCO] + 0.22 µM, p < 0.01), accompanied by a 7.5% increase in estimated cerebral metabolic rate for oxygen ( p = 0.038). Our results are consistent with an improvement in cellular redox state, suggesting oxygen-limited metabolism above recognised ischaemic pbrO2 thresholds. Diffusion limitation or mitochondrial inhibition might explain these findings. Further investigation is warranted to establish optimal oxygenation to sustain aerobic metabolism after acute brain injury.
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Affiliation(s)
- Arnab Ghosh
- 1 Neurocritical Care, University College London Hospitals, National Hospital for Neurology & Neurosurgery, London, UK
| | - David Highton
- 1 Neurocritical Care, University College London Hospitals, National Hospital for Neurology & Neurosurgery, London, UK
| | - Christina Kolyva
- 2 Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Ilias Tachtsidis
- 2 Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Clare E Elwell
- 2 Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Martin Smith
- 1 Neurocritical Care, University College London Hospitals, National Hospital for Neurology & Neurosurgery, London, UK.,2 Department of Medical Physics and Biomedical Engineering, University College London, London, UK.,3 University College London Hospitals National Institute for Health Research Biomedical Research Centre, London, UK
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15
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Abstract
Part I of this review discussed the similarities between embryogenesis, mammalian adaptions to hypoxia (primarily driven by hypoxia-inducible factor-1 [HIF-1]), ischemia-reperfusion injury (and its relationship with reactive oxygen species), hibernation, diving animals, cancer, and sepsis, and it focused on the common characteristics that allow cells and organisms to survive in these states. Part II of this review describes techniques by which researchers gain insight into subcellular energetics and identify potential future tools for clinicians. In particular, P nuclear magnetic resonance to measure high-energy phosphates, serum lactate measurements, the use of near-infrared spectroscopy to measure the oxidation state of cytochrome aa3, and the ability of the protoporphyrin IX-triplet state lifetime technique to measure mitochondrial oxygen tension are discussed. In addition, this review discusses novel treatment strategies such as hyperbaric oxygen, preconditioning, exercise training, therapeutic gases, as well as inhibitors of HIF-1, HIF prolyl hydroxylase, and peroxisome proliferator-activated receptors.
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Affiliation(s)
- Robert H Thiele
- From the Department of Anesthesiology, University of Virginia, Charlottesville, Virginia
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17
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Nosrati R, Lin S, Ramadeen A, Monjazebi D, Dorian P, Toronov V. Cerebral Hemodynamics and Metabolism During Cardiac Arrest and Cardiopulmonary Resuscitation Using Hyperspectral Near Infrared Spectroscopy. Circ J 2017; 81:879-887. [PMID: 28302943 DOI: 10.1253/circj.cj-16-1225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Maintaining cerebral oxygen delivery and metabolism during cardiac arrest (CA) through resuscitation is essential to improve the survival rate while avoiding brain injury. The effect of CA and cardiopulmonary resuscitation (CPR) on cerebral and muscle oxygen delivery and metabolism is not clearly quantified.Methods and Results:A novel hyperspectral near-infrared spectroscopy (hNIRS) technique was developed and evaluated to measure cerebral oxygen delivery and aerobic metabolism during ventricular fibrillation (VF) CA and CPR in 14 pigs. The hNIRS parameters were measured simultaneously on the dura and skull to investigate the validity of non-invasive hNIRS measurements. In addition, we compared the hNIRS data collected simultaneously on the brain and muscle. Following VF induction, oxygenated hemoglobin (HbO2) declined with a 9.9 s delay and then cytochrome-c-oxidase (Cyt-ox) decreased on average 4.4 s later (P<0.05). CPR improved cerebral metabolism, which was reflected by an average 0.4 μmol/L increase in Cyt-ox, but had no significant effect on HbO2, deoxygenated hemoglobin (HHb) and tissue oxygen saturation (tSO2). Cyt-ox had greater correlation with HHb than HbO2. Muscle metabolism during VF and CPR was significantly different from that of the brain. The total hemoglobin concentration (in the brain only) increased after ~200 s of untreated CA, which is most likely driven by cerebral autoregulation through vasodilation. CONCLUSIONS Overall, hNIRS showed consistent measurements of hemodynamics and metabolism during CA and CPR.
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Affiliation(s)
- Reyhaneh Nosrati
- Department of Physics, Ryerson University.,Medical Physics, Sunnybrook Health Sciences Centre
| | - Steve Lin
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.,Department of Medicine, University of Toronto
| | - Andrew Ramadeen
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital
| | | | - Paul Dorian
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital.,Department of Medicine, University of Toronto
| | - Vladislav Toronov
- Department of Physics, Ryerson University.,Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital
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19
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Broadband near-infrared spectroscopy can detect cyanide-induced cytochrome aa 3 inhibition in rats: a proof of concept study. Can J Anaesth 2016; 64:376-384. [PMID: 28008565 DOI: 10.1007/s12630-016-0803-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/31/2016] [Accepted: 12/13/2016] [Indexed: 10/20/2022] Open
Abstract
PURPOSE Clinically available near-infrared spectroscopy (NIRS) devices use two to five wavelengths of light to measure the relative amounts of oxyhemoglobin and deoxyhemoglobin in tissue to determine tissue hemoglobin oxygen saturation (StO2). In addition to StO2, broadband NIRS devices (using hundreds of wavelengths of light) may be able to measure the oxidation state of mitochondrial cytochrome aa3 (Cytox) which reflects the subcellular energetic state. We hypothesize that broadband NIRS devices can measure Cytox independent of changes in hemoglobin saturation. METHODS In this prospective non-randomized study, 20 male Sprague-Dawley rats (300 g) were anesthetized with isoflurane, tracheally intubated, and ventilated with 100% O2 containing 2% isoflurane. They were subsequently instrumented with a broadband NIRS device that used a halogen light source coupled to an emitting fibreoptic cable. Three receiving fibreoptic cables were utilized; one analyzed the light source and the other two were directed at the base of the skull. Each receiving fibre was connected to a spectrometer to measure light intensity. Sodium cyanide (NaCN) 5 mg·kg-1 iv was injected in order to produce cytochrome aa3 reduction. Two to three minutes after injection, oxygen was eliminated and 100% nitrogen (i.e., anoxia) was used for ventilation in order to induce a reduction in both cytochrome aa3 and hemoglobin desaturation. Changes in the cytochrome oxidation state and hemoglobin oxygenation were calculated using a broadband algorithm and compared before and after both the NaCN and anoxia interventions. RESULTS The NaCN injection resulted in a decrease in median [interquartile range (IQR)] deoxyhemoglobin (-0.014 [-0.29 to -0.005] arbitrary units [AU]; P < 0.001), an increase in oxyhemoglobin (0.013 [-0.011 to 0.031] AU; P < 0.001), and a reduction in cytochrome aa3 (-0.015 [-0.020 to -0.011] AU; P < 0.001). Anoxia resulted in an increase in median [IQR] deoxyhemoglobin (0.13 [0.11 to 0.18] AU; P < 0.001), a decrease in oxyhemoglobin (-0.17 [-0.22 to -0.15] AU; P < 0.001), and a reduction in cytochrome aa3 (-0.04 [-0.06 to -0.03] AU; P < 0.001). CONCLUSION Broadband NIRS can effectively measure the directionality of changes in both Cytox and StO2 by uncoupling the cytochrome and hemoglobin signals through inhibition of the electron transport chain and anoxia.
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Phan P, Highton D, Lai J, Smith M, Elwell C, Tachtsidis I. Multi-channel multi-distance broadband near-infrared spectroscopy system to measure the spatial response of cellular oxygen metabolism and tissue oxygenation. BIOMEDICAL OPTICS EXPRESS 2016; 7:4424-4440. [PMID: 27895985 PMCID: PMC5119585 DOI: 10.1364/boe.7.004424] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 05/22/2023]
Abstract
We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state of cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) in the adult human brain. The main components of the instrument are two customized spectrographs and two light sources. Each spectrograph is lens-based to improve light throughput, has a grating enhanced to optimise reflection in the near-infrared (NIR) spectral region and uses a front illuminated cooled CCD camera (-70° C) with a square chip dimension of 12.3 x 12.3 mm (512 x 512 pixels). Each light source uses a 50W halogen bulb with a gold plated mirror to increase the intensity of the NIR light. Each light source was connected to a custom-built bifurcated fibre bundle to create two source fibre bundles (3.2 mm diameter each). Each spectrograph received light input from another custom-built fibre bundle comprised of six individual bundles (one with 0.6 mm diameter and the other five with 1.5 mm diameter). All fibre bundles were fixed on a 3D printed optode holder (two light sources x two fibre bundles each = four probes; and two spectrographs x six fibre bundles each = 12 probes) that allowed 24 multi-distance channels across the forehead (six channels at 20 mm, three channels at 30 mm and 15 channels at 35 mm) and six TOI measurements. We demonstrated the use of the system in a cohort of nine healthy adult volunteers during prefrontal cortex functional activation using the Stroop task. We have observed functional responses identified as significant increase in Δ[HbO2], decrease in Δ[HHb] and increase in Δ[oxCCO] in five channels (out of 12), that overlay the left and right dorsolateral prefrontal cortices. There was no observable TOI functional response and we have shown small variations in TOI across different sites within the same subject and within the same site across subjects.
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Affiliation(s)
- Phong Phan
- Department of Medical Physics and Biomedical Engineering, UCL, London WC1E 6BT, UK
| | - David Highton
- Neurocritical Care Unit, The National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, UK
| | - Jonathan Lai
- Department of Medical Physics and Biomedical Engineering, UCL, London WC1E 6BT, UK
| | - Martin Smith
- Department of Medical Physics and Biomedical Engineering, UCL, London WC1E 6BT, UK
- Neurocritical Care Unit, The National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, UK
| | - Clare Elwell
- Department of Medical Physics and Biomedical Engineering, UCL, London WC1E 6BT, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, UCL, London WC1E 6BT, UK
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21
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Guhathakurta D, Dutta A. Computational Pipeline for NIRS-EEG Joint Imaging of tDCS-Evoked Cerebral Responses-An Application in Ischemic Stroke. Front Neurosci 2016; 10:261. [PMID: 27378836 PMCID: PMC4913108 DOI: 10.3389/fnins.2016.00261] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/23/2016] [Indexed: 12/22/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) modulates cortical neural activity and hemodynamics. Electrophysiological methods (electroencephalography-EEG) measure neural activity while optical methods (near-infrared spectroscopy-NIRS) measure hemodynamics coupled through neurovascular coupling (NVC). Assessment of NVC requires development of NIRS-EEG joint-imaging sensor montages that are sensitive to the tDCS affected brain areas. In this methods paper, we present a software pipeline incorporating freely available software tools that can be used to target vascular territories with tDCS and develop a NIRS-EEG probe for joint imaging of tDCS-evoked responses. We apply this software pipeline to target primarily the outer convexity of the brain territory (superficial divisions) of the middle cerebral artery (MCA). We then present a computational method based on Empirical Mode Decomposition of NIRS and EEG time series into a set of intrinsic mode functions (IMFs), and then perform a cross-correlation analysis on those IMFs from NIRS and EEG signals to model NVC at the lesional and contralesional hemispheres of an ischemic stroke patient. For the contralesional hemisphere, a strong positive correlation between IMFs of regional cerebral hemoglobin oxygen saturation and the log-transformed mean-power time-series of IMFs for EEG with a lag of about -15 s was found after a cumulative 550 s stimulation of anodal tDCS. It is postulated that system identification, for example using a continuous-time autoregressive model, of this coupling relation under tDCS perturbation may provide spatiotemporal discriminatory features for the identification of ischemia. Furthermore, portable NIRS-EEG joint imaging can be incorporated into brain computer interfaces to monitor tDCS-facilitated neurointervention as well as cortical reorganization.
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Affiliation(s)
| | - Anirban Dutta
- Department of Psychology and Neurosciences, IfADo - Leibniz Research Centre for Working Environment and Human Factors Dortmund, Germany
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Endophenotypes for Age-Related Macular Degeneration: Extending Our Reach into the Preclinical Stages of Disease. J Clin Med 2015; 3:1335-56. [PMID: 25568804 PMCID: PMC4284143 DOI: 10.3390/jcm3041335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The key to reducing the individual and societal burden of age-related macular degeneration (AMD)-related vision loss, is to be able to initiate therapies that slow or halt the progression at a point that will yield the maximum benefit while minimizing personal risk and cost. There is a critical need to find clinical markers that, when combined with the specificity of genetic testing, will identify individuals at the earliest stages of AMD who would benefit from preventive therapies. These clinical markers are endophenotypes for AMD, present in those who are likely to develop AMD, as well as in those who have clinical evidence of AMD. Clinical characteristics associated with AMD may also be possible endophenotypes if they can be detected before or at the earliest stages of the condition, but we and others have shown that this may not always be valid. Several studies have suggested that dynamic changes in rhodopsin regeneration (dark adaptation kinetics and/or critical flicker fusion frequencies) may be more subtle indicators of AMD-associated early retinal dysfunction. One can test for the relevance of these measures using genetic risk profiles based on known genetic risk variants. These functional measures may improve the sensitivity and specificity of predictive models for AMD and may also serve to delineate clinical subtypes of AMD that may differ with respect to prognosis and treatment.
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Arifler D, Zhu T, Madaan S, Tachtsidis I. Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations. BIOMEDICAL OPTICS EXPRESS 2015; 6:933-47. [PMID: 25798316 PMCID: PMC4361446 DOI: 10.1364/boe.6.000933] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 05/19/2023]
Abstract
We analyze broadband near-infrared spectroscopic measurements obtained from newborn piglets subjected to hypoxia-ischemia and we aim to identify optimal wavelength combinations for monitoring cerebral tissue chromophores. We implement an optimization routine based on the genetic algorithm to perform a heuristic search for discrete wavelength combinations that can provide accurate concentration information when benchmarked against the gold standard of 121 wavelengths. The results indicate that it is possible to significantly reduce the number of measurement wavelengths used in conjunction with spectroscopic algorithms and still achieve a high performance in estimating changes in concentrations of oxyhemoglobin, deoxyhemoglobin, and oxidized cytochrome c oxidase. While the use of a 3-wavelength combination leads to mean recovery errors of up to 10%, these errors drop to less than 4% with 4 or 5 wavelengths and to even less than 2% with 8 wavelengths.
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Affiliation(s)
- Dizem Arifler
- Physics Group, Middle East Technical University, Northern Cyprus Campus, Kalkanli, via Mersin 10
Turkey
| | - Tingting Zhu
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Sara Madaan
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
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24
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Lee J, Kim JG, Mahon SB, Mukai D, Yoon D, Boss GR, Patterson SE, Rockwood G, Isom G, Brenner M. Noninvasive optical cytochrome c oxidase redox state measurements using diffuse optical spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:055001. [PMID: 24788369 PMCID: PMC4006145 DOI: 10.1117/1.jbo.19.5.055001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 03/01/2014] [Accepted: 03/07/2014] [Indexed: 05/28/2023]
Abstract
A major need exists for methods to assess organ oxidative metabolic states in vivo. By contrasting the responses to cyanide (CN) poisoning versus hemorrhage in animal models, we demonstrate that diffuse optical spectroscopy (DOS) can detect cytochrome c oxidase (CcO) redox states. Intermittent decreases in inspired O2 from 100% to 21% were applied before, during, and after CN poisoning, hemorrhage, and resuscitation in rabbits. Continuous DOS measurements of total hemoglobin, oxyhemoglobin, deoxyhemoglobin, and oxidized and reduced CcO from muscle were obtained. Rabbit hemorrhage was accomplished with stepwise removal of blood, followed by blood resuscitation. CN treated rabbits received 0.166 mg/min NaCN infusion. During hemorrhage, CcO redox state became reduced concurrently with decreases in oxyhemoglobin, resulting from reduced tissue oxygen delivery and hypoxia. In contrast, during CN infusion, CcO redox state decreased while oxyhemoglobin concentration increased due to CN binding and reduction of CcO with resultant inhibition of the electron transport chain. Spectral absorption similarities between hemoglobin and CcO make noninvasive spectroscopic distinction of CcO redox states difficult. By contrasting physiological perturbations of CN poisoning versus hemorrhage, we demonstrate that DOS measured CcO redox state changes are decoupled from hemoglobin concentration measurement changes.
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Affiliation(s)
- Jangwoen Lee
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
| | - Jae G. Kim
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
- Gwangju Institute of Science and Technology, School of Information and Communications, Department of Medical System Engineering, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Sari B. Mahon
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
| | - David Mukai
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
| | - David Yoon
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
| | - Gerry R. Boss
- University of California San Diego, Department of Medicine, 9500 Gilman Dr., La Jolla, California 92093
| | - Steven E. Patterson
- University of Minnesota, Department of Pharmacology, 516 Delaware Street SE, Minneapolis, Minnesota 55455
| | - Gary Rockwood
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Gary Isom
- Purdue University, Department of Medicinal Chemistry and Molecular Pharmacology, 575 Stadium Mall Drive, West Lafayette, Indiana 47907
| | - Matthew Brenner
- University of California Irvine, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612
- University of California Irvine Medical Center, Department of Pulmonary and Critical Care, 333 West City Boulevard, Suite 400, Orange, California 92868
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25
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Drury PP, Davidson JO, van den Heuij LG, Tan S, Silverman RB, Ji H, Blood AB, Fraser M, Bennet L, Gunn AJ. Partial neuroprotection by nNOS inhibition during profound asphyxia in preterm fetal sheep. Exp Neurol 2013; 250:282-92. [PMID: 24120436 DOI: 10.1016/j.expneurol.2013.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/30/2013] [Accepted: 10/02/2013] [Indexed: 11/19/2022]
Abstract
Preterm brain injury is partly associated with hypoxia-ischemia starting before birth. Excessive nitric oxide production during HI may cause nitrosative stress, leading to cell membrane and mitochondrial damage. We therefore tested the hypothesis that therapy with a new, selective neuronal nitric oxide synthase (nNOS) inhibitor, JI-10 (0.022mg/kg bolus, n=8), given 30min before 25min of complete umbilical cord occlusion was protective in preterm fetal sheep at 101-104day gestation (term is 147days), compared to saline (n=8). JI-10 had no effect on fetal blood pressure, heart rate, carotid and femoral blood flow, total EEG power, nuchal activity, temperature or intracerebral oxygenation on near-infrared spectroscopy during or after occlusion. JI-10 was associated with later onset of post-asphyxial seizures compared with saline (p<0.05), and attenuation of the subsequent progressive loss of cytochrome oxidase (p<0.05). After 7days recovery, JI-10 was associated with improved neuronal survival in the caudate nucleus (p<0.05), but not the putamen or hippocampus, and more CNPase positive oligodendrocytes in the periventricular white matter (p<0.05). In conclusion, prophylactic nNOS inhibition before profound asphyxia was associated with delayed onset of seizures, slower decline of cytochrome oxidase and partial white and gray matter protection, consistent with protection of mitochondrial function.
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Affiliation(s)
- Paul P Drury
- Department of Physiology, University of Auckland, Auckland, New Zealand.
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Abstract
Resting-state functional near-infrared spectroscopy (R-fNIRS) is an active area of interest and is currently attracting considerable attention as a new imaging tool for the study of resting-state brain function. Using variations in hemodynamic concentration signals, R-fNIRS measures the brain’s low-frequency spontaneous neural activity, combining the advantages of portability, low-cost, high temporal sampling rate and less physical burden to participants. The temporal synchronization of spontaneous neuronal activity in anatomically separated regions is referred to as resting-state functional connectivity (RSFC). In the past several years, an increasing body of R-fNIRS RSFC studies has led to many important findings about functional integration among local or whole-brain regions by measuring inter-regional temporal synchronization. Here, we summarize recent advances made in the R-fNIRS RSFC methodologies, from the detection of RSFC (e.g., seed-based correlation analysis, independent component analysis, whole-brain correlation analysis, and graph-theoretical topological analysis), to the assessment of RSFC performance (e.g., reliability, repeatability, and validity), to the application of RSFC in studying normal development and brain disorders. The literature reviewed here suggests that RSFC analyses based on R-fNIRS data are valid and reliable for the study of brain function in healthy and diseased populations, thus providing a promising imaging tool for cognitive science and clinics.
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Affiliation(s)
- Haijing Niu
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
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Kolyva C, Ghosh A, Tachtsidis I, Highton D, Cooper CE, Smith M, Elwell CE. Cytochrome c oxidase response to changes in cerebral oxygen delivery in the adult brain shows higher brain-specificity than haemoglobin. Neuroimage 2013; 85 Pt 1:234-44. [PMID: 23707584 PMCID: PMC3898943 DOI: 10.1016/j.neuroimage.2013.05.070] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 05/05/2013] [Accepted: 05/13/2013] [Indexed: 11/19/2022] Open
Abstract
The redox state of cerebral mitochondrial cytochrome c oxidase monitored with near-infrared spectroscopy (Δ[oxCCO]) is a signal with strong potential as a non-invasive, bedside biomarker of cerebral metabolic status. We hypothesised that the higher mitochondrial density of brain compared to skin and skull would lead to evidence of brain-specificity of the Δ[oxCCO] signal when measured with a multi-distance near-infrared spectroscopy (NIRS) system. Measurements of Δ[oxCCO] as well as of concentration changes in oxygenated (Δ[HbO2]) and deoxygenated haemoglobin (Δ[HHb]) were taken at multiple source-detector distances during systemic hypoxia and hypocapnia (decrease in cerebral oxygen delivery), and hyperoxia and hypercapnia (increase in cerebral oxygen delivery) from 15 adult healthy volunteers. Increasing source-detector spacing is associated with increasing light penetration depth and thus higher sensitivity to cerebral changes. An increase in Δ[oxCCO] was observed during the challenges that increased cerebral oxygen delivery and the opposite was observed when cerebral oxygen delivery decreased. A consistent pattern of statistically significant increasing amplitude of the Δ[oxCCO] response with increasing light penetration depth was observed in all four challenges, a behaviour that was distinctly different from that of the haemoglobin chromophores, which did not show this statistically significant depth gradient. This depth-dependence of the Δ[oxCCO] signal corroborates the notion of higher concentrations of CCO being present in cerebral tissue compared to extracranial components and highlights the value of NIRS-derived Δ[oxCCO] as a brain-specific signal of cerebral metabolism, superior in this aspect to haemoglobin. NIRS was used to measure oxidised cytochrome c oxidase (Δ[oxCCO]) in healthy brain. Δ[oxCCO] changed in the same direction as changes in cerebral oxygen delivery. Magnitude of Δ[oxCCO] response increased with increasing light penetration depth. Corresponding haemoglobin changes showed no dependence on light penetration depth. NIRS-measured Δ[oxCCO] has higher brain specificity than haemoglobin.
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Affiliation(s)
- Christina Kolyva
- Dept. of Medical Physics and Bioengineering, University College London, London, UK.
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Kolyva C, Ghosh A, Tachtsidis I, Highton D, Smith M, Elwell CE. Dependence on NIRS source-detector spacing of cytochrome c oxidase response to hypoxia and hypercapnia in the adult brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 789:353-359. [PMID: 23852515 PMCID: PMC4037984 DOI: 10.1007/978-1-4614-7411-1_47] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Transcranial near-infrared spectroscopy (NIRS) provides an assessment of cerebral oxygen metabolism by monitoring concentration changes in oxidised cytochrome c oxidase Δ[oxCCO]. We investigated the response of Δ[oxCCO] to global changes in cerebral oxygen delivery at different source-detector separations in 16 healthy adults. Hypoxaemia was induced by delivery of a hypoxic inspired gas mix and hypercapnia by addition of 6 % CO2 to the inspired gases. A hybrid optical spectrometer was used to measure frontal cortex light absorption and scattering at discrete wavelengths and broadband light attenuation at 20, 25, 30 and 35 mm. Without optical scattering changes, a decrease in cerebral oxygen delivery, resulting from the reduction in arterial oxygen saturation during hypoxia, led to a decrease in Δ[oxCCO]. In contrast, Δ[oxCCO] increased when cerebral oxygen delivery increased due to increased cerebral blood flow during hypercapnia. In both cases the magnitude of the Δ[oxCCO] response increased from the detectors proximal (measuring superficial tissue layers) to the detectors distal (measuring deep tissue layers) to the broadband light source. We conclude that the Δ[oxCCO] response to hypoxia and hypercapnia appears to be dependent on penetration depth, possibly reflecting differences between the intra- and extracerebral tissue concentration of cytochrome c oxidase.
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Affiliation(s)
- Christina Kolyva
- Department of Medical Physics and Bioengineering, University College London, London, UK.
| | - Arnab Ghosh
- Neurocritical Care Unit, University College Hospitals, London, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Bioengineering, University College London, London, UK
| | - David Highton
- Neurocritical Care Unit, University College Hospitals, London, UK
| | - Martin Smith
- Neurocritical Care Unit, University College Hospitals, London, UK
| | - Clare E Elwell
- Department of Medical Physics and Bioengineering, University College London, London, UK
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Ghosh A, Kolyva C, Tachtsidis I, Highton D, Elwell CE, Smith M. Reduction of cytochrome C oxidase during vasovagal hypoxia-ischemia in human adult brain: a case study. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 789:21-27. [PMID: 23852472 PMCID: PMC4038000 DOI: 10.1007/978-1-4614-7411-1_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Near-infrared spectroscopy (NIRS)-derived measurement of oxidized cytochrome c oxidase concentration ([oxCCO]) has been used as an assessment of the adequacy of cerebral oxygen delivery. We report a case in which a reduction in conscious level was associated with a reduction in [oxCCO]. Hypoxaemia was induced in a 31-year-old, healthy male subject as part of an ongoing clinical study. Midway through the hypoxaemic challenge, the subject experienced an unexpected vasovagal event with bradycardia, hypotension and reduced cerebral blood flow (middle cerebral artery blood flow velocity decrease from 70 to 30 cm s(-1)) that induced a brief reduction in conscious level. An associated decrease in [oxCCO] was observed at 35 mm (-1.6 μM) but only minimal change (-0.1 μM) at 20-mm source-detector separation. A change in optical scattering was observed, but path length remained unchanged. This unexpected physiological event provides an unusual example of a severe reduction in cerebral oxygen delivery and is the first report correlating change in clinical status with changes in [oxCCO].
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Affiliation(s)
- Arnab Ghosh
- Neurocritical Care Unit, University College Hospitals, WC1N 3BG, London, UK.
| | - Christina Kolyva
- Medical Physics & Bioengineering, University College London, WC1E 6BT, London, UK
| | - Ilias Tachtsidis
- Medical Physics & Bioengineering, University College London, WC1E 6BT, London, UK
| | - David Highton
- Neurocritical Care Unit, University College Hospitals, WC1N 3BG, London, UK
| | - Clare E Elwell
- Medical Physics & Bioengineering, University College London, WC1E 6BT, London, UK
| | - Martin Smith
- Neurocritical Care Unit, University College Hospitals, WC1N 3BG, London, UK
- Medical Physics & Bioengineering, University College London, WC1E 6BT, London, UK
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Kolyva C, Tachtsidis I, Ghosh A, Moroz T, Cooper CE, Smith M, Elwell CE. Systematic investigation of changes in oxidized cerebral cytochrome c oxidase concentration during frontal lobe activation in healthy adults. BIOMEDICAL OPTICS EXPRESS 2012; 3:2550-66. [PMID: 23082295 PMCID: PMC3469997 DOI: 10.1364/boe.3.002550] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/10/2012] [Accepted: 06/30/2012] [Indexed: 05/02/2023]
Abstract
Using transcranial near-infrared spectroscopy (NIRS) to measure changes in the redox state of cerebral cytochrome c oxidase (Δ[oxCCO]) during functional activation in healthy adults is hampered by instrumentation and algorithm issues. This study reports the Δ[oxCCO] response measured in such a setting and investigates possible confounders of this measurement. Continuous frontal lobe NIRS measurements were collected from 11 healthy volunteers during a 6-minute anagram-solving task, using a hybrid optical spectrometer (pHOS) that combines multi-distance frequency and broadband components. Only data sets showing a hemodynamic response consistent with functional activation were interrogated for a Δ[oxCCO] response. Simultaneous systemic monitoring data were also available. Possible influences on the Δ[oxCCO] response were systematically investigated and there was no effect of: 1) wavelength range chosen for fitting the measured attenuation spectra; 2) constant or measured, with the pHOS in real-time, differential pathlength factor; 3) systemic hemodynamic changes during functional activation; 4) changes in optical scattering during functional activation. The Δ[oxCCO] response measured in the presence of functional activation was heterogeneous, with the majority of subjects showing significant increase in oxidation, but others having a decrease. We conclude that the heterogeneity in the Δ[oxCCO] response is physiological and not induced by confounding factors in the measurements.
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Affiliation(s)
- Christina Kolyva
- Medical Physics & Bioengineering, University College London,
London WC1E 6BT, UK
| | - Ilias Tachtsidis
- Medical Physics & Bioengineering, University College London,
London WC1E 6BT, UK
| | - Arnab Ghosh
- Neurocritical Care Unit, University College London Hospitals,
London WC1N 3BG, UK
| | - Tracy Moroz
- Medical Physics & Bioengineering, University College London,
London WC1E 6BT, UK
| | - Chris E. Cooper
- Biological Sciences, University of Essex, Colchester CO4 3SQ,
UK
| | - Martin Smith
- Medical Physics & Bioengineering, University College London,
London WC1E 6BT, UK
- Neurocritical Care Unit, University College London Hospitals,
London WC1N 3BG, UK
| | - Clare E. Elwell
- Medical Physics & Bioengineering, University College London,
London WC1E 6BT, UK
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Boas DA, Franceschini MA. Haemoglobin oxygen saturation as a biomarker: the problem and a solution. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4407-24. [PMID: 22006898 PMCID: PMC3263786 DOI: 10.1098/rsta.2011.0250] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy measures of haemoglobin oxygen saturation are often used as an indicator of sufficient oxygen delivery to assess injury susceptibility and tissue damage. They have also often been used as a surrogate measure of oxygen metabolism. Unfortunately, these measures have generally failed to provide robust indicators of injury and metabolism. In this paper, we first review when haemoglobin oxygen saturation does work as a robust indicator, and then detail when and why it fails for assessing brain injury and breast cancer. Finally, we discuss the solution to obtain more robust measures of tissue injury and cancer by combining oxygen saturation measurements with measures of blood flow and volume to more accurately estimate oxygen metabolism.
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Affiliation(s)
- David A Boas
- Optics Division of the Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, 149 13th St rm 2301, Charlestown, MA 02129, USA.
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Troitzsch D, Moosdorf R, Vogt S. Microvascular tissue oxygenation and oxidative metabolism changes in the pedicled latissimus dorsi muscle during graded hypoxia: correlation between near infrared and 31P nuclear magnetic resonance spectroscopy. J Surg Res 2011; 176:337-42. [PMID: 21705019 DOI: 10.1016/j.jss.2011.04.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/05/2011] [Accepted: 04/28/2011] [Indexed: 11/18/2022]
Abstract
BACKGROUND In this study, the microvascular tissue oxygenation and oxidative muscle metabolism during graded hypoxia and reoxygenation were examined in a rabbit model by near-infrared (NIR) spectroscopy and correlated with high-energy phosphates measured by (31)P nuclear magnetic resonance (NMR) spectroscopy. MATERIALS AND METHODS Graded hypoxia was performed in a New Zealand rabbit model (n = 20, 2.0 ± 0.4 kg) by a stepwise reduction of the fraction of inspired oxygen (FiO(2)) from 0.3 to 0.05 (intervention group versus control group). Recovery and reoxygenation were achieved using FiO(2) of 0.3. A noninvasive NIR spectroscopy sensor and NMR probe was positioned on the surface of the prepared pedicled latissimus dorsi muscle. Microvascular tissue oxygenation (oxyhemoglobin, HbO(2); deoxyhemoglobin, HHb) and redox state of cytochrome oxidase (CytOx) were measured by NIR spectroscopy and correlated with standard values of oxidative muscle metabolism (phosphocreatine, PCr; adenosine triphosphate, ATP) measured by time-resolved (31)P NMR spectroscopy (4.7T). RESULTS Significant correlation was found between PCr and HbO(2) (r = 0.85, P < 0.001) and HHb (r = -0.75, P < 0.001). β-ATP levels correlated significantly with CytOx (r = 0.87, P < 0.001). CONCLUSIONS The data suggest that changes in high-energy phosphates (PCr- and ATP-levels) correlate closely with microvascular tissue oxygenation (HbO(2), HHb, CytOx) measured by NIR spectroscopy.
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Affiliation(s)
- Dirk Troitzsch
- Biomedical Research Center, Cardiovascular Research Lab, Department of Cardiac and Thoracic Vascular Surgery, University Medical Center, Philipps-University of Marburg/Lahn, Marburg/Lahn, Germany
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Abstract
Cerebral hypothermia reduces brain injury and improves behavioral recovery after hypoxia-ischemia (HI) at birth. However, using current enrolment criteria many infants are not helped, and conversely, a significant proportion of control infants survive without disability. In order to further improve treatment we need better biomarkers of injury. A 'true' biomarker for the phase of evolving, 'treatable' injury would allow us to identify not only whether infants are at risk of damage, but also whether they are still able to benefit from intervention. Even a less specific measure that allowed either more precise early identification of infants at risk of adverse neurodevelopmental outcome would reduce the variance of outcome of trials, improving trial power while reducing the number of infants unnecessarily treated. Finally, valid short-term surrogates for long term outcome after treatment would allow more rapid completion of preliminary evaluation and thus allow new strategies to be tested more rapidly. Experimental studies have demonstrated that there is a relatively limited 'window of opportunity' for effective treatment (up to about 6-8h after HI, the 'latent phase'), before secondary cell death begins. We critically evaluate the utility of proposed biochemical, electronic monitoring, and imaging biomarkers against this framework. This review highlights the two central limitations of most presently available biomarkers: that they are most precise for infants with severe injury who are already easily identified, and that their correlation is strongest at times well after the latent phase, when injury is no longer 'treatable'. This is an important area for further research.
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Affiliation(s)
- L. Bennet
- Corresponding author. Dr Laura Bennet, Professor, Fetal Physiology and Neuroscience Group Department of Physiology, The University of Auckland, Private Bag 92019 Auckland, New Zealand Tel.: +64 9 373 7599 ext. 84890; fax: +64 9 373 7499. (L. Bennet)
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Bicuculline-induced seizures: a challenge for optical and biochemical modeling of the cytochrome oxidase CuA NIRS signal. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009. [PMID: 19227461 DOI: 10.1007/978-0-387-85998-9_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
The effect of seizures on brain blood flow and metabolism has been extensively studied. However, few studies have focused on mitochondria. We used near infrared spectroscopy (NIRS) to study hemoglobin and cytochrome oxidase changes during seizures, induced by the GABA antagonist bicuculline, in the adult rat. A broadband spectroscopy system was used with the optodes placed across the rat head. We focused on the initial seizures post-bicuculline addition during which oxyhemoglobin (HbO2) increased, deoxyhemoglobin (HHb) decreased and total hemoglobin (Hbtot) increased. The NIRS signal associated with the oxidised CuA centre of mitochondrial cytochrome c oxidase (oxCCO) decreased. At the highest bicuculline doses (0.25 mg/animal) the maximum values recorded were: delta HbO2 = +19 +/- 7 microM; delta HHb = -12 +/- 4 microM; delta Hbtot = +7 +/- 4 microM, delta oxCCO = - 1.7 +/- 0.3 microM. These results are broadly in line with other NIRS studies. However, previous measurements of NADH fluorescence indicate oxidation of the mitochondrial redox chain under these conditions. The changes induced by bicuculline provide an interesting challenge to the physics and biochemistry of using NIRS to study mitochondrial redox states in vivo and we explore the possible spectroscopic and/or biochemical meaning of these apparent anomalies.
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Mertes PM, Baumann A, Audibert G. [Transfusion in neurosurgery]. Transfus Clin Biol 2008; 15:205-11. [PMID: 18930420 DOI: 10.1016/j.tracli.2008.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
Abstract
In neurosurgery, the question of the optimal transfusion "trigger" remains a controversial matter. Regarding the brain, the current data are still incomplete, justifying the continuation of experimental and clinical studies. The existing expert advices are based on these rather poor data and would probably evolve after the completion of clinical studies in progress. In spine surgery, the situation is simpler and the transfusional stakes are quite similar to those of orthopedics and traumatology. With regard to hemostasis, standardized recommendations exist depending on the laboratory test results or the anticoagulant treatments of the patient.
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Affiliation(s)
- P-M Mertes
- Département d'anesthésie-réanimation, hôpital Central, CHU de Nancy, Nancy, France.
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Tisdall MM, Tachtsidis I, Leung TS, Elwell CE, Smith M. Increase in cerebral aerobic metabolism by normobaric hyperoxia after traumatic brain injury. J Neurosurg 2008; 109:424-32. [PMID: 18759572 DOI: 10.3171/jns/2008/109/9/0424] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Traumatic brain injury (TBI) is associated with depressed aerobic metabolism and mitochondrial dysfunction. Normobaric hyperoxia (NBH) has been suggested as a treatment for TBI, but studies in humans have produced equivocal results. In this study the authors used brain tissue O(2) tension measurement, cerebral microdialysis, and near-infrared spectroscopy to study the effects of NBH after TBI. They investigated the effects on cellular and mitochondrial redox states measured by the brain tissue lactate/pyruvate ratio (LPR) and the change in oxidized cytochrome c oxidase (CCO) concentration, respectively. METHODS The authors studied 8 adults with TBI within the first 48 hours postinjury. Inspired oxygen percentage at normobaric pressure was increased from baseline to 60% for 60 minutes and then to 100% for 60 minutes before being returned to baseline for 30 minutes. RESULTS The results are presented as the median with the interquartile range in parentheses. During the 100% inspired oxygen percentage phase, brain tissue O2 tension increased by 7.2 kPa (range 4.5-9.6 kPa) (p < 0.0001), microdialysate lactate concentration decreased by 0.26 mmol/L (range 0.0-0.45 mmol/L) (p = 0.01), microdialysate LPR decreased by 1.6 (range 1.0-2.3) (p = 0.02), and change in oxidized CCO concentration increased by 0.21 mumol/L (0.13-0.38 micromol/L) (p = 0.0003). There were no significant changes in intracranial pressure or arterial or microdialysate glucose concentration. The change in oxidized CCO concentration correlated with changes in brain tissue O(2) tension (r(s)= 0.57, p = 0.005) and in LPR (r(s)= -0.53, p = 0.006). CONCLUSIONS The authors have demonstrated oxidation in cerebral cellular and mitochondrial redox states during NBH in adults with TBI. These findings are consistent with increased aerobic metabolism and suggest that NBH has the potential to improve outcome after TBI. Further studies are warranted.
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Affiliation(s)
- Martin M Tisdall
- Department of Neuroanaesthesia and Neurocritical Care, The National Hospital for Neurology and Neurosurgery, UK
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Kawauchi S, Sato S, Ooigawa H, Nawashiro H, Ishihara M, Kikuchi M. Simultaneous measurement of changes in light absorption due to the reduction of cytochrome c oxidase and light scattering in rat brains during loss of tissue viability. APPLIED OPTICS 2008; 47:4164-76. [PMID: 18670575 DOI: 10.1364/ao.47.004164] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We performed the simultaneous measurement of intrinsic optical signals (IOSs) related to metabolic activity and cellular and subcellular morphological characteristics, i.e., light scattering for a rat global ischemic brain model made by rapidly removing blood by saline infusion. The signals were measured on the basis of multiwavelength diffuse reflectances in which 605 and 830 nm were used to detect the IOSs that are thought to be dominantly affected by redox changes of heme aa(3) and CuA in cytochrome c oxidase (CcO), respectively. For measuring the scattering signal, the wavelength that was found to be most insensitive to the absorption changes, e.g., approximately 620 nm, was used. The measurements suggested that an increase in the absorption due to reduction of heme aa(3) occurred soon after blood clearance, and this was followed by a large triphasic change in light scattering, during which time a decrease in the absorption due to reduction of CuA occurred. Through the triphasic scattering change, scattering signals increased by 5.2 +/- 1.5% (n = 5), and the increase in light scattering showed significant correlation with both the reflectance intensity changes at 605 and 830 nm. This suggests that morphological changes in cells correlate with reductions of heme aa(3) and CuA. Histological analysis of tissue after the triphasic scattering change showed no alteration in either the nuclei or the cytoskeleton, but electron microscopic observation revealed deformed, enlarged mitochondria and expanded dendrites. These findings suggest that the simultaneous measurement of absorption signals related to the redox changes in the CcO and the scattering signal is useful for monitoring tissue viability in the brain.
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Affiliation(s)
- Satoko Kawauchi
- Department of Medical Engineering, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
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Onozawa A, Kikukawa A, Miyamoto Y. A new evaluation method for +Gz tolerance with loratadine by using a near-infrared spectroscopy. DYNAMIC MEDICINE : DM 2008; 7:3. [PMID: 18226263 PMCID: PMC2265702 DOI: 10.1186/1476-5918-7-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/28/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Loratadine (Claritin), an over-the-counter antihistamine in U.S. and UK, is acceptable for use without adverse side effects by aircrew with mild or moderate allergic or other situations requiring an antihistamine. Although +Gz (head to foot direction) tolerance testing for aircrew with loratadine has not been documented in the published literature, it is commonly accepted that loratadine dose not effect +Gz tolerance. The purpose of this study was to offer and validate a new evaluation method for +Gz tolerance testing with loratadine by using a near-infrared spectroscopy (NIRS). METHODS A double-blind, placebo-controlled, randomized, crossover protocol was used to administer 10 mg of loratadine or placebo in nine healthy subjects. The subjects didn't wear anti-G suit. The +Gz exposure profiles consisted of, in series, a gradual onset ran (0.1 G.sec-1) to the subject's visual end-point (peripheral light loss) or loss of consciousness (GLOC), and rapid onset run (1.0 G.sec-1) to the subject's same end-point. In this study, G-level tolerance was defined as the +Gz level at visual end-point and/or at GLOC. As a subject's G-duration tolerance, we measured the total time (seconds) during rapid onset run. Otherwise, to confirm the effect of loratadine on +Gz tolerance, we measured the cerebral NIRS variables (hemoglobin concentration changes and tissue oxygenation index) as a new quantitative method for +Gz tolerance during a centrifuge experiments. RESULTS No significant differences were observed in +Gz tolerance (+Gz level, duration time and NIRS variables) between subjects taking loratadine and placebo. CONCLUSION Our results demonstrate that loratadine has no detectable effect on +Gz tolerance by using a new method with cerebral NIRS variables and the traditional method with +Gz level and duration time. This study represents the first use of a quantitative parameter such as cerebral NIRS variables to assess the effects of a drug on acceleration tolerance.
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Affiliation(s)
- Akihiko Onozawa
- Aeromedical Laboratory, Japan Air Self-Defense Force, Tachikawa, Tokyo, Japan
| | - Azusa Kikukawa
- Aeromedical Laboratory, Japan Air Self-Defense Force, Tachikawa, Tokyo, Japan
| | - Yoshinori Miyamoto
- Aeromedical Laboratory, Japan Air Self-Defense Force, Tachikawa, Tokyo, Japan
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Kanamaru Y, Kikukawa A, Miyamoto Y, Hirafuji M. Dimenhydrinate effect on cerebral oxygen status and salivary chromogranin-A during cognitive tasks. Prog Neuropsychopharmacol Biol Psychiatry 2008; 32:107-15. [PMID: 17765381 DOI: 10.1016/j.pnpbp.2007.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 07/23/2007] [Accepted: 07/23/2007] [Indexed: 11/29/2022]
Abstract
To investigate the effects of dimenhydrinate on cerebral oxygen status (COS; cerebral oxygenated hemoglobin concentration changes) and salivary chromogranin-A (CgA) during a cognitive test battery, a double-blind, placebo-controlled, randomized, crossover protocol was used to examine the effect of 50 mg of dimenhydrinate or placebo in 12 subjects. This test battery includes tests of both reaction time and fundamental cognitive ability and was used in the assessment of pilots. Poor cognitive performance was observed in the subjects taking dimenhydrinate. We used two-channel near-infrared spectroscopy to investigate the effects of dimenhydrinate on the COS. With the one exception of shifting attention task in the left forehead, no significant difference was found between dimenhydrinate and placebo during the tasks of the test battery. Under placebo treatment, on the other hand, CgA levels were significantly elevated during cognitive testing when compared with baseline. However, CgA levels were not significantly elevated above baseline following dimenhydrinate. The present study is one of the first to demonstrate that the first-generation antihistamine drugs altered the responses of salivary CgA during cognitive tasks. The changes in salivary CgA secretion, as a result of dimenhydrinate administration, may serve as a sensitive biomarker of a psychological status such as a drug-induced sedation during the performance of a cognitive test battery. Further studies, however, are required to examine the usefulness of this sensitive biomarker in investigation of psychological agents during cognitive tasks.
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Affiliation(s)
- Yoshiki Kanamaru
- 2nd Division, Aeromedical Laboratory, Japan Air Self-Defense Force, 1-2-10 Sakae-cho, Tachikawa-shi, Tokyo 190-8585, Japan
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40
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Tisdall MM, Tachtsidis I, Leung TS, Elwell CE, Smith M. Near-infrared spectroscopic quantification of changes in the concentration of oxidized cytochrome c oxidase in the healthy human brain during hypoxemia. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:024002. [PMID: 17477717 DOI: 10.1117/1.2718541] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The near-IR cytochrome c oxidase (CCO) signal has potential as a clinical marker of changes in mitochondrial oxygen utilization. We examine the CCO signal response to reduced oxygen delivery in the healthy human brain. We induced a reduction in arterial oxygen saturation from baseline levels to 80% in eight healthy adult humans, while minimizing changes in end tidal carbon dioxide tension. We measured changes in the cerebral concentrations of oxidized CCO (Delta[oxCCO]), oxyhemoglobin (Delta[HbO(2)]), and deoxyhemoglobin (Delta[HHb]) using broadband near-IR spectroscopy (NIRS), and estimated changes in cerebral oxygen delivery (ecDO(2)) using pulse oximetry and transcranial Doppler ultrasonography. Results are presented as median (interquartile range). At the nadir of hypoxemia ecDO(2) decreased by 9.2 (5.4 to 12.1)% (p<0.0001), Delta[oxCCO] decreased by 0.24 (0.06 to 0.28) micromoles/l (p<0.01), total hemoglobin concentration increased by 2.83 (2.27 to 4.46) micromoles/l (p<0.0001), and change in hemoglobin difference concentration (Delta[Hbdiff]=Delta[HbO(2)]-Delta[HHb]) decreased by 12.72 (11.32 to 16.34) micromoles/l (p<0.0001). Change in ecDO(2) correlated with Delta[oxCCO] (r=0.78, p<0.001), but not with either change in total hemoglobin concentration or Delta[Hbdiff]. This is the first description of cerebral Delta[oxCCO] during hypoxemia in healthy adults. Studies are ongoing to investigate the clinical relevance of this signal in patients with traumatic brain injury.
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Affiliation(s)
- Martin M Tisdall
- The National Hospital for Neurology and Neurosurgery, Department of Neuroanaesthesia and Neurocritical Care, Queen Square, London WC1N 3BG, United Kingdom.
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Cooper CE, Giulivi C. Nitric oxide regulation of mitochondrial oxygen consumption II: Molecular mechanism and tissue physiology. Am J Physiol Cell Physiol 2007; 292:C1993-2003. [PMID: 17329402 DOI: 10.1152/ajpcell.00310.2006] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nitric oxide (NO) is an intercellular signaling molecule; among its many and varied roles are the control of blood flow and blood pressure via activation of the heme enzyme, soluble guanylate cyclase. A growing body of evidence suggests that an additional target for NO is the mitochondrial oxygen-consuming heme/copper enzyme, cytochrome c oxidase. This review describes the molecular mechanism of this interaction and the consequences for its likely physiological role. The oxygen reactive site in cytochrome oxidase contains both heme iron (a(3)) and copper (Cu(B)) centers. NO inhibits cytochrome oxidase in both an oxygen-competitive (at heme a(3)) and oxygen-independent (at Cu(B)) manner. Before inhibition of oxygen consumption, changes can be observed in enzyme and substrate (cytochrome c) redox state. Physiological consequences can be mediated either by direct "metabolic" effects on oxygen consumption or via indirect "signaling" effects via mitochondrial redox state changes and free radical production. The detailed kinetics suggest, but do not prove, that cytochrome oxidase can be a target for NO even under circumstances when guanylate cyclase, its primary high affinity target, is not fully activated. In vivo organ and whole body measures of NO synthase inhibition suggest a possible role for NO inhibition of cytochrome oxidase. However, a detailed mapping of NO and oxygen levels, combined with direct measures of cytochrome oxidase/NO binding, in physiology is still awaited.
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Affiliation(s)
- Chris E Cooper
- Dept. of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom.
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Tachtsidis I, Tisdall M, Leung TS, Cooper CE, Delpy DT, Smith M, Elwell CE. Investigation ofin vivomeasurement of cerebral cytochrome-c-oxidase redox changes using near-infrared spectroscopy in patients with orthostatic hypotension. Physiol Meas 2006; 28:199-211. [PMID: 17237591 DOI: 10.1088/0967-3334/28/2/008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have previously used a continuous four-wavelength near-infrared spectrometer to measure changes in the cerebral concentrations of oxy-haemoglobin (Delta[HbO(2)] and deoxy-haemoglobin (Delta[HHb]) during head-up tilt in patients with primary autonomic failure. The measured changes in light attenuation also allow calculation of changes in the concentration of oxidized cytochrome-c-oxidase (Delta[(ox)CCO]), and this paper analyses the Delta[(ox)CCO] during the severe episodes of orthostatic hypotension produced by this experimental protocol. We studied 12 patients during a passive change in position from supine to a 60 degrees head-up tilt. The challenge caused a reduction in mean blood pressure of 59.93 (+/-26.12) mmHg (Mean (+/-SD), p < 0.0001), which was associated with a reduction in the total concentration of haemoglobin (Delta[HbT] = Delta[HbO(2)] + Delta[HHb]) of 5.02 (+/-3.81) microM (p < 0.0001) and a reduction in the haemoglobin difference concentration (Delta[Hb(diff)] = Delta[HbO(2)] - Delta[HHb]) of 14.4 (+/-6.73) microM (p < 0.0001). We observed a wide range of responses in Delta[(ox)CCO]. Six patients demonstrated a drop in Delta[(ox)CCO] (0.17 +/- 0.15 microM); four patients demonstrated no change (0.01 +/- 0.12 microM) and two patients showed an increase in Delta[(ox)CCO] (0.21 +/- 0.01 microM). Investigation of the association between the changes in concentrations of haemoglobin species and the Delta[(ox)CCO] for each patient show a range of relationships. This suggests that a simple mechanism for crosstalk, which might produce artefactual changes in [(ox)CCO], is not present between the haemoglobin and the (ox)CCO NIRS signals. Further investigation is required to determine the clinical significance of the changes in [(ox)CCO].
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Affiliation(s)
- I Tachtsidis
- Department of Medical Physics and Bioengineering, Malet Place Engineering Building, University College London, Gower Street, London, UK.
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De Visscher G, Verreth W, Blockx H, van Rossem K, Holvoet P, Flameng W. Application of NIRS in Mice: A Study Comparing the Oxygenation of Cerebral Blood and Main Tissue Oxygenation of Mice and Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 578:197-202. [PMID: 16927693 DOI: 10.1007/0-387-29540-2_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Geofrey De Visscher
- Laboratory of Cardiovascular Research, CEHA, Catholic University of Leuven, Leuven, Belgium
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44
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Gagnon RE, Macnab AJ, Gagnon FA, Leblanc JG. Brain, spine, and muscle cytochrome Cu-A redox patterns of change during hypothermic circulatory arrest in swine. Comp Biochem Physiol A Mol Integr Physiol 2005; 141:264-70. [PMID: 16023395 DOI: 10.1016/j.cbpb.2005.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Revised: 03/29/2005] [Accepted: 04/02/2005] [Indexed: 11/23/2022]
Abstract
Past near infrared spectroscopy (NIRS) studies have reported different changes in cytochrome C oxidase (Cyt) redox status during similar interventions that cause tissue ischaemia. We investigated whether there were distinctive differences when NIRS signals were obtained simultaneously from different tissues during total circulatory arrest. Forty-two healthy 10 kg commercial swine (Sus scrofa) on cardiopulmonary bypass, each underwent 2 to 8 sequential periods of hypothermic circulatory arrest for 7.5 min. Prior to each arrest, key physiologic variables were adjusted to 1 of 81 combinations of high, normal, or low levels of core temperature, hematocrit, pH, and serum glucose. Each combination was repeated at least twice. Simultaneous NIRS monitoring yielded 202 brain, 191 spine, and 199 muscle Cyt data sets, which were then classified into 13 distinctive patterns of change. The data sets always differed between tissues in the same arrest trial and subject. Typically, brain Cyt rapidly became more reduced at the start of arrest and changed little thereafter, muscle Cyt behaved comparably to brain Cyt but continued to become reduced throughout the arrest, and spine Cyt either did not change status or gradually became more reduced over the course of arrest. The spine pattern's mean rate of change was 12 times slower than those of the brain or muscle. The Cyt patterns of change were classified into 13 groups which were significantly related to core temperature in the brain and spine, and hematocrit in muscle. The respiratory response in mitochondria during systemic circulatory arrest differs between brain, spine and muscle tissues in the same subject.
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Affiliation(s)
- Roy E Gagnon
- Dept Pediatrics, Dept Surgery, Children's and Women's Health Centre, University of British Columbia, Vancouver, Canada
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Gagnon RE, Gagnon FA, Macnab AJ, LeBlanc JG. Temperature, hematocrit, pH, and glucose 4-way ANOVA of cytochrome C oxidase redox status during systemic cold circulatory arrest in swine. Metab Brain Dis 2005; 20:105-13. [PMID: 15938129 DOI: 10.1007/s11011-005-4148-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED Various investigators using near infrared spectroscopy (NIRS) have reported differing patterns of cytochrome C oxidase (cytochrome a,a3) redox status in similar brain oxygenation studies. We investigated whether distinctive differences could be due to combinations of variations in temperature, hematocrit, pH, and glucose. METHODS Thirty-six healthy 10 kg commercial juvenile swine on cardiopulmonary bypass underwent 2-8 sequential periods of circulatory arrest. Prior to each arrest, key physiological variables were adjusted to match a random selection of one of 81 combinations of high, normal, or low levels of hypothermia, hematocrit, pH, and serum glucose. In the course of the study, the combinations were repeated twice to yield 162 NIRS data sets. RESULTS The mean rate of change in net oxidized minus reduced cytochrome a,a3 redox status in the brain following 7.5 min of ischemia was 0.49 +/- 0.26 micromol L(-1) min(-1), and, the corresponding mean magnitude of change was -1.23 +/- 0.57 micromol L(-1). The rate of change was influenced by temperature but not by hematocrit, pH, or glucose, either singly or in combination. CONCLUSION The respiratory response in mitochondria during systemic circulatory arrest is significantly influenced by temperature.
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Affiliation(s)
- Roy E Gagnon
- Department of Pediatrics, Children's & Women's Health Centre, University of British Columbia, Vancouver, Canada
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Ferrari M, Mottola L, Quaresima V. Principles, techniques, and limitations of near infrared spectroscopy. ACTA ACUST UNITED AC 2005; 29:463-87. [PMID: 15328595 DOI: 10.1139/h04-031] [Citation(s) in RCA: 601] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the last decade the study of the human brain and muscle energetics underwent a radical change, thanks to the progressive introduction of noninvasive techniques, including near-infrared (NIR) spectroscopy (NIRS). This review summarizes the most recent literature about the principles, techniques, advantages, limitations, and applications of NIRS in exercise physiology and neuroscience. The main NIRS instrumentations and measurable parameters will be reported. NIR light (700-1000 m) penetrates superficial layers (skin, subcutaneous fat, skull, etc.) and is either absorbed by chromophores (oxy- and deoxyhemoglobin and myoglobin) or scattered within the tissue. NIRS is a noninvasive and relatively low-cost optical technique that is becoming a widely used instrument for measuring tissue O2 saturation, changes in hemoglobin volume and, indirectly, brain/muscle blood flow and muscle O2 consumption. Tissue O2 saturation represents a dynamic balance between O2 supply and O2 consumption in the small vessels such as the capillary, arteriolar, and venular bed. The possibility of measuring the cortical activation in response to different stimuli, and the changes in the cortical cytochrome oxidase redox state upon O2 delivery changes, will also be mentioned.
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Affiliation(s)
- Marco Ferrari
- Department of Biomedical Sciences and Technologies, University of L'Aquila, Italy
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Fujii F, Nodasaka Y, Nishimura G, Tamura M. Anoxia induces matrix shrinkage accompanied by an increase in light scattering in isolated brain mitochondria. Brain Res 2004; 999:29-39. [PMID: 14746919 DOI: 10.1016/j.brainres.2003.11.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It is important to monitor mitochondrial conditions, and light scattering (LS) measurements have been applied to the detection of morphological changes in mitochondria in vivo. Little is known about the morphological and LS responses of brain mitochondria to oxygen withdrawal, a critical factor in cell death. We have therefore investigated the morphological and LS responses of isolated brain mitochondria to anoxia. Anoxia induced an increase in LS, reflecting mitochondrial matrix shrinkage. This response was reversible, but was reduced by adding digitonin, which disrupted the outer membrane selectively. This suggested that integrity of the outer membrane was necessary for the matrix response. We further examined the effects of Mg2+ and ATP on the responses because both exist in cells and modulate the changes in matrix volume. Although Mg2+ and ATP reduced the rates of increase and decrease in LS, respectively, the magnitudes of the increases in LS caused by anoxia stayed at over 80% of the control level (no Mg2+) in the presence of Mg2+ and ATP. This suggested that the increase in LS occurred in cells containing Mg2+ and ATP during anoxia. In contrast, that caused by inhibitors of the electron transport chain was reduced to below 30% of the control level in the presence of Mg2+. The present in vitro study provides a basis for interpretation of LS signals from mitochondria in brain research during oxygen withdrawal.
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Affiliation(s)
- Fumihiko Fujii
- Biophysics, Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan.
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Kobayashi N, Hoshi Y, Tamura M. A perfused rat brain model maintaining the connection between the central and peripheral nervous systems. J Neurosci Methods 2004; 132:191-8. [PMID: 14706717 DOI: 10.1016/j.jneumeth.2003.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have developed a new perfused brain model in rats. In this model, the cerebral circulation is separated from the systemic circulation, while the connections between the central and peripheral nervous systems are preserved. After bilateral common carotid, external carotid and vertebral artery ligation, bilateral common carotid arteries were cannulated to infuse rinsed human type O red blood cells mixed with modified Ringer's solution. To drain cerebral venous blood, external jugular veins were cannulated. Normal electrocortical activities were observed on electroencephalograms (EEGs) for more than 1h after the beginning of the perfusion. Somatosensory evoked potentials (SEPs) were also recorded. Direct infusion of pentylenetetrazol (PTZ) into the brain induced epileptic discharges on the EEGs and active dilation of cerebral arterioles, which was accompanied by an increase in systemic blood pressure (BP). The present model, in which we can change cerebral blood flow (CBF) and/or cerebral metabolism without directly affecting the systemic circulation, will provide a new approach to brain research.
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Affiliation(s)
- Norio Kobayashi
- Biophysics Group, Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan
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Springett RJ, Wylezinska M, Cady EB, Hollis V, Cope M, Delpy DT. The Oxygen Dependency of Cerebral Oxidative Metabolism in the Newborn Piglet Studied with 31P NMRS and NIRS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 530:555-63. [PMID: 14562751 DOI: 10.1007/978-1-4615-0075-9_53] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Mean cerebral saturation and changes in the oxidation state of the CuA centre of cytochrome oxidase were measured by near infra-red spectroscopy simultaneously with phosphorous metabolites and intracellular pH measured using 31P NMR spectroscopy during transient anoxia (inspired oxygen fraction = 0.0 for 105 seconds) in the newborn piglet brain. By collecting high quality 31P spectra every 10 seconds, it was possible to resolve the delay between the onset of anoxia and the fall in PCr and to show that the CuA centre of cytochrome oxidase reduced simultaneously with the fall in PCr. From these observations it is concluded that, at normoxia, oxygen tension at the mitochondrial level is substantially above a critical value at which oxidative metabolism becomes oxygen dependent.
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Affiliation(s)
- Roger J Springett
- Department of Radiology, Dartmouth College, Hanover, New Hampshire, USA
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Chen Y, Mu C, Intes X, Chance B. Adaptive calibration for object localization in turbid media with interfering diffuse photon density waves. APPLIED OPTICS 2002; 41:7325-7333. [PMID: 12477125 DOI: 10.1364/ao.41.007325] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The amplitude cancellation method that uses dual out-of-phase sources (a phased array system) can sensitively detect and locate small objects in turbid media. The balance of these two sources is crucial to the system's detection sensitivity and accuracy. We describe a convenient method with which to adaptively calibrate the amplitudes of the two sources at each scanning position by use of low-frequency modulation of the intensity of the in-phase and the antiphase sources. We achieve accurate localization ability of the phased array system by accounting for the influence of asymmetrical boundaries and the heterogeneous background absorption. Experimental data on human breast phantoms demonstrate that localization accuracy within several millimeters has been accomplished through this method.
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Affiliation(s)
- Yu Chen
- Department of Biophysics and Biochemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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