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Lénárt N, Cserép C, Császár E, Pósfai B, Dénes Á. Microglia-neuron-vascular interactions in ischemia. Glia 2024; 72:833-856. [PMID: 37964690 DOI: 10.1002/glia.24487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
Cerebral ischemia is a devastating condition that results in impaired blood flow in the brain leading to acute brain injury. As the most common form of stroke, occlusion of cerebral arteries leads to a characteristic sequence of pathophysiological changes in the brain tissue. The mechanisms involved, and comorbidities that determine outcome after an ischemic event appear to be highly heterogeneous. On their own, the processes leading to neuronal injury in the absence of sufficient blood supply to meet the metabolic demand of the cells are complex and manifest at different temporal and spatial scales. While the contribution of non-neuronal cells to stroke pathophysiology is increasingly recognized, recent data show that microglia, the main immune cells of the central nervous system parenchyma, play previously unrecognized roles in basic physiological processes beyond their inflammatory functions, which markedly change during ischemic conditions. In this review, we aim to discuss some of the known microglia-neuron-vascular interactions assumed to contribute to the acute and delayed pathologies after cerebral ischemia. Because the mechanisms of neuronal injury have been extensively discussed in several excellent previous reviews, here we focus on some recently explored pathways that may directly or indirectly shape neuronal injury through microglia-related actions. These discoveries suggest that modulating gliovascular processes in different forms of stroke and other neurological disorders might have presently unexplored therapeutic potential in combination with neuroprotective and flow restoration strategies.
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Affiliation(s)
- Nikolett Lénárt
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Eszter Császár
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Pósfai
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ádám Dénes
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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2
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Kann O. Lactate as a supplemental fuel for synaptic transmission and neuronal network oscillations: Potentials and limitations. J Neurochem 2024; 168:608-631. [PMID: 37309602 DOI: 10.1111/jnc.15867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/14/2023]
Abstract
Lactate shuttled from the blood circulation, astrocytes, oligodendrocytes or even activated microglia (resident macrophages) to neurons has been hypothesized to represent a major source of pyruvate compared to what is normally produced endogenously by neuronal glucose metabolism. However, the role of lactate oxidation in fueling neuronal signaling associated with complex cortex function, such as perception, motor activity, and memory formation, is widely unclear. This issue has been experimentally addressed using electrophysiology in hippocampal slice preparations (ex vivo) that permit the induction of different neural network activation states by electrical stimulation, optogenetic tools or receptor ligand application. Collectively, these studies suggest that lactate in the absence of glucose (lactate only) impairs gamma (30-70 Hz) and theta-gamma oscillations, which feature high energy demand revealed by the cerebral metabolic rate of oxygen (CMRO2, set to 100%). The impairment comprises oscillation attenuation or moderate neural bursts (excitation-inhibition imbalance). The bursting is suppressed by elevating the glucose fraction in energy substrate supply. By contrast, lactate can retain certain electric stimulus-induced neural population responses and intermittent sharp wave-ripple activity that features lower energy expenditure (CMRO2 of about 65%). Lactate utilization increases the oxygen consumption by about 9% during sharp wave-ripples reflecting enhanced adenosine-5'-triphosphate (ATP) synthesis by oxidative phosphorylation in mitochondria. Moreover, lactate attenuates neurotransmission in glutamatergic pyramidal cells and fast-spiking, γ-aminobutyric acid (GABA)ergic interneurons by reducing neurotransmitter release from presynaptic terminals. By contrast, the generation and propagation of action potentials in the axon is regular. In conclusion, lactate is less effective than glucose and potentially detrimental during neural network rhythms featuring high energetic costs, likely through the lack of some obligatory ATP synthesis by aerobic glycolysis at excitatory and inhibitory synapses. High lactate/glucose ratios might contribute to central fatigue, cognitive impairment, and epileptic seizures partially seen, for instance, during exhaustive physical exercise, hypoglycemia and neuroinflammation.
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Affiliation(s)
- Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
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3
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Galijasevic M, Steiger R, Treichl SA, Ho WM, Mangesius S, Ladenhauf V, Deeg J, Gruber L, Ouaret M, Regodic M, Lenhart L, Pfausler B, Grams AE, Petr O, Thomé C, Gizewski ER. Could Phosphorous MR Spectroscopy Help Predict the Severity of Vasospasm? A Pilot Study. Diagnostics (Basel) 2024; 14:841. [PMID: 38667486 PMCID: PMC11049300 DOI: 10.3390/diagnostics14080841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/02/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
One of the main causes of the dismal prognosis in patients who survive the initial bleeding after aneurysmal subarachnoidal hemorrhage is the delayed cerebral ischaemia caused by vasospasm. Studies suggest that cerebral magnesium and pH may potentially play a role in the pathophysiology of this adverse event. Using phosphorous magnetic resonance spectrocopy (31P-MRS), we calculated the cerebral magnesium (Mg) and pH levels in 13 patients who suffered from aSAH. The values between the group that developed clinically significant vasospasm (n = 7) and the group that did not (n = 6) were compared. The results of this study show significantly lower cerebral Mg levels (p = 0.019) and higher pH levels (p < 0.001) in the cumulative group (all brain voxels together) in patients who developed clinically significant vasospasm. Further clinical studies on a larger group of carefully selected patients are needed in order to predict clinically significant vasospasm.
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Affiliation(s)
- Malik Galijasevic
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Ruth Steiger
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Stephanie Alice Treichl
- Department of Neurosurgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.A.T.); (W.M.H.); (O.P.); (C.T.)
| | - Wing Man Ho
- Department of Neurosurgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.A.T.); (W.M.H.); (O.P.); (C.T.)
| | - Stephanie Mangesius
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Valentin Ladenhauf
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Johannes Deeg
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Leonhard Gruber
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Miar Ouaret
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Milovan Regodic
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lukas Lenhart
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Bettina Pfausler
- Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Astrid Ellen Grams
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Ondra Petr
- Department of Neurosurgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.A.T.); (W.M.H.); (O.P.); (C.T.)
| | - Claudius Thomé
- Department of Neurosurgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.A.T.); (W.M.H.); (O.P.); (C.T.)
| | - Elke Ruth Gizewski
- Department of Radiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.G.); (S.M.); (V.L.); (J.D.); (L.G.); (M.O.); (M.R.); (L.L.); (A.E.G.); (E.R.G.)
- Neuroimaging Research Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria
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Carlson AP, Mayer AR, Cole C, van der Horn HJ, Marquez J, Stevenson TC, Shuttleworth CW. Cerebral autoregulation, spreading depolarization, and implications for targeted therapy in brain injury and ischemia. Rev Neurosci 2024; 0:revneuro-2024-0028. [PMID: 38581271 DOI: 10.1515/revneuro-2024-0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 03/25/2024] [Indexed: 04/08/2024]
Abstract
Cerebral autoregulation is an intrinsic myogenic response of cerebral vasculature that allows for preservation of stable cerebral blood flow levels in response to changing systemic blood pressure. It is effective across a broad range of blood pressure levels through precapillary vasoconstriction and dilation. Autoregulation is difficult to directly measure and methods to indirectly ascertain cerebral autoregulation status inherently require certain assumptions. Patients with impaired cerebral autoregulation may be at risk of brain ischemia. One of the central mechanisms of ischemia in patients with metabolically compromised states is likely the triggering of spreading depolarization (SD) events and ultimately, terminal (or anoxic) depolarization. Cerebral autoregulation and SD are therefore linked when considering the risk of ischemia. In this scoping review, we will discuss the range of methods to measure cerebral autoregulation, their theoretical strengths and weaknesses, and the available clinical evidence to support their utility. We will then discuss the emerging link between impaired cerebral autoregulation and the occurrence of SD events. Such an approach offers the opportunity to better understand an individual patient's physiology and provide targeted treatments.
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Affiliation(s)
- Andrew P Carlson
- Department of Neurosurgery, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
- Department of Neurosciences, 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Andrew R Mayer
- 168528 Mind Research Network , 1101 Yale, Blvd, NE, Albuquerque, NM, 87106, USA
| | - Chad Cole
- Department of Neurosurgery, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | - Harm J van der Horn
- 168528 Mind Research Network , 1101 Yale, Blvd, NE, Albuquerque, NM, 87106, USA
| | - Joshua Marquez
- 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Taylor C Stevenson
- Department of Neurosurgery, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | - C William Shuttleworth
- Department of Neurosciences, 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
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Franx BAA, Lebrun F, Chin Joe Kie L, Deffieux T, Vivien D, Bonnard T, Dijkhuizen RM. Dynamics of cerebral blood volume during and after middle cerebral artery occlusion in rats - Comparison between ultrafast ultrasound and dynamic susceptibility contrast-enhanced MRI measurements. J Cereb Blood Flow Metab 2024; 44:333-344. [PMID: 38126356 PMCID: PMC10870967 DOI: 10.1177/0271678x231220698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 11/06/2023] [Accepted: 11/19/2023] [Indexed: 12/23/2023]
Abstract
Tomographic perfusion imaging techniques are integral to translational stroke research paradigms that advance our understanding of the disease. Functional ultrasound (fUS) is an emerging technique that informs on cerebral blood volume (CBV) through ultrasensitive Doppler and flow velocity (CBFv) through ultrafast localization microscopy. It is not known how experimental results compare with a classical CBV-probing technique such as dynamic susceptibility contrast-enhanced perfusion MRI (DSC-MRI). To that end, we assessed hemodynamics based on uUS (n = 6) or DSC-MRI (n = 7) before, during and up to three hours after 90-minute filament-induced middle cerebral artery occlusion (MCAO) in rats. Recanalization was followed by a brief hyperperfusion response, after which CBV and CBFv temporarily normalized but progressively declined after one hour in the lesion territory. DSC-MRI data corroborated the incomplete restoration of CBV after recanalization, which may have been caused by the free-breathing anesthetic regimen. During occlusion, MCAO-induced hypoperfusion was more discrepant between either technique, likely attributable to artefactual signal mechanisms related to slow flow, and processing algorithms employed for either technique. In vivo uUS- and DSC-MRI-derived measures of CBV enable serial whole-brain assessment of post-stroke hemodynamics, but readouts from both techniques need to be interpreted cautiously in situations of very low blood flow.
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Affiliation(s)
- Bart AA Franx
- Translational Neuroimaging Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Florent Lebrun
- Normandie University, UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Institute Blood and Brain @ Caen-Normandie (BB@C), Caen, France
- ETAP-Lab, STROK@LLIANCE, 13 Rue du bois de la champelle, 54500, Vandoeuvre-les-Nancy, France
| | - Lois Chin Joe Kie
- Translational Neuroimaging Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Thomas Deffieux
- Institute of Physics for Medicine Paris, INSERM U1273, ESPCI Paris, CNRS UMR 8063, PSL Université Recherche, Paris, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Institute Blood and Brain @ Caen-Normandie (BB@C), Caen, France
- CHU Caen, Department of Clinical Research, CHU Caen, Côte de Nacre, France
| | - Thomas Bonnard
- Normandie University, UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Institute Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Rick M Dijkhuizen
- Translational Neuroimaging Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
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Daher A, Payne S. The conducted vascular response as a mediator of hypercapnic cerebrovascular reactivity: A modelling study. Comput Biol Med 2024; 170:107985. [PMID: 38245966 DOI: 10.1016/j.compbiomed.2024.107985] [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: 11/08/2023] [Revised: 12/29/2023] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
It is well established that the cerebral blood flow (CBF) shows exquisite sensitivity to changes in the arterial blood partial pressure of CO2 ( [Formula: see text] ), which is reflected by an index termed cerebrovascular reactivity. In response to elevations in [Formula: see text] (hypercapnia), the vessels of the cerebral microvasculature dilate, thereby decreasing the vascular resistance and increasing CBF. Due to the challenges of access, scale and complexity encountered when studying the microvasculature, however, the mechanisms behind cerebrovascular reactivity are not fully understood. Experiments have previously established that the cholinergic release of the Acetylcholine (ACh) neurotransmitter in the cortex is a prerequisite for the hypercapnic response. It is also known that ACh functions as an endothelial-dependent agonist, in which the local administration of ACh elicits local hyperpolarization in the vascular wall; this hyperpolarization signal is then propagated upstream the vascular network through the endothelial layer and is coupled to a vasodilatory response in the vascular smooth muscle (VSM) layer in what is known as the conducted vascular response (CVR). Finally, experimental data indicate that the hypercapnic response is more strongly correlated with the CO2 levels in the tissue than in the arterioles. Accordingly, we hypothesize that the CVR, evoked by increases in local tissue CO2 levels and a subsequent local release of ACh, is responsible for the CBF increase observed in response to elevations in [Formula: see text] . By constructing physiologically grounded dynamic models of CBF and control in the cerebral vasculature, ones that integrate the available knowledge and experimental data, we build a new model of the series of signalling events and pathways underpinning the hypercapnic response, and use the model to provide compelling evidence that corroborates the aforementioned hypothesis. If the CVR indeed acts as a mediator of the hypercapnic response, the proposed mechanism would provide an important addition to our understanding of the repertoire of metabolic feedback mechanisms possessed by the brain and would motivate further in-vivo investigation. We also model the interaction of the hypercapnic response with dynamic cerebral autoregulation (dCA), the collection of mechanisms that the brain possesses to maintain near constant CBF despite perturbations in pressure, and show how the dCA mechanisms, which otherwise tend to be overlooked when analysing experimental results of cerebrovascular reactivity, could play a significant role in shaping the CBF response to elevations in [Formula: see text] . Such in-silico models can be used in tandem with in-vivo experiments to expand our understanding of cerebrovascular diseases, which continue to be among the leading causes of morbidity and mortality in humans.
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Affiliation(s)
- Ali Daher
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, United Kingdom.
| | - Stephen Payne
- Institute of Applied Mechanics, National Taiwan University, Taiwan
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Poh K, Bustam A, Hasan MS, Mohd Yunos N, Cham CY, Lim FJ, Ahmad Zahedi AZ, Zambri A, Noor Azhar M. Isotonic balanced fluid versus 0.9% saline in patients with moderate to severe traumatic brain injury: A double-blinded randomised controlled trial. Am J Emerg Med 2024; 77:106-114. [PMID: 38118385 DOI: 10.1016/j.ajem.2023.11.064] [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: 08/11/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 12/22/2023] Open
Abstract
BACKGROUND AND IMPORTANCE Traumatic brain injury (TBI) is a global health concern with significant economic impact. Optimal fluid therapy aims to restore intravascular volume, maintain cerebral perfusion pressure and blood flow, thus preventing secondary brain injury. While 0.9% saline (NS) is commonly used, concerns about acid-base and electrolyte imbalance and development of acute kidney injury (AKI) lead to consideration of balanced fluids as an alternative. OBJECTIVES This study aimed to compare the outcomes of patients with moderate to severe TBI treated with Sterofundin (SF) versus NS. DESIGN, SETTINGS AND PARTICIPANTS A double-blinded randomised controlled trial of patients aged 18 to 65 years with TBI was conducted at the University Malaya Medical Centre from February 2017 to November 2019. INTERVENTION OR EXPOSURE Patients were randomly assigned to receive either NS or SF. The study fluids were administered for 72 h as continuous infusions or boluses. Participants, investigators, and staff were blinded to the fluid type. OUTCOMES MEASURE AND ANALYSIS The primary outcome was in-hospital mortality. Relative risk (RR) with 95% confidence interval (CI) was calculated. MAIN RESULTS A total of 70 patients were included in the analysis, with 38 in the NS group and 32 in the SF group. The in-hospital mortality rate were 3 (7.9%) in the NS group vs. 4 (12.5%) in the SF group, RR = 1.29 (95% CI, 0.64 to 2.59; p = 0.695). No patients developed AKI and required renal replacement therapy. ICP on day 3 was significantly higher in the SF group (18.60 ± 9.26) compared to 12.77 ± 3.63 in the NS group, (95% CI, -11.46 to 0.20; p = 0.037). There were no significant differences in 3-day biochemical parameters and cerebral perfusion pressure, ventilator-free days, length of ICU stay, or Glasgow Outcome Scale-Extended (GOS-E) score at 6 months. CONCLUSIONS In patients with moderate to severe TBI, the use of SF was not associated with reduced in-hospital mortality, development of AKI, or improved 6-month GOS-E when compared to NS.
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Affiliation(s)
- Khadijah Poh
- Department of Emergency Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Aida Bustam
- Department of Emergency Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Mohd Shahnaz Hasan
- Department of Anaesthesiology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Nor'azim Mohd Yunos
- Department of Anaesthesiology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Chun Yoong Cham
- Division of Neurosurgery, Department of Surgery, University Malaya Medical Centre, Kuala Lumpur, Malaysia
| | - Fang Jen Lim
- Department of Emergency Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | | | - Aliyah Zambri
- Department of Emergency Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Muhaimin Noor Azhar
- Department of Emergency Medicine, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia.
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Cho SM, Gusdon AM. Assessing Acute Brain Injury after Rapid Reduction of PaCO 2 using Plasma Biomarkers in Patients Undergoing ECMO. Neurocrit Care 2024:10.1007/s12028-024-01944-0. [PMID: 38356080 DOI: 10.1007/s12028-024-01944-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 02/16/2024]
Affiliation(s)
- Sung-Min Cho
- Division of Neuroscience Critical Care, Departments of Neurology, Neurosurgery, Anesthesiology, and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Aaron M Gusdon
- Division of Neurocritical Care, Department of Neurosurgery, McGovern School of Medicine, University of Texas Health Science Center, Houston, TX, USA
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Gonzalez D, Dahiya G, Mutirangura P, Ergando T, Mello G, Singh R, Bentho O, Elliott AM. Post Cardiac Arrest Care in the Cardiac Intensive Care Unit. Curr Cardiol Rep 2024; 26:35-49. [PMID: 38214836 DOI: 10.1007/s11886-023-02015-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/08/2023] [Indexed: 01/13/2024]
Abstract
PURPOSE OF REVIEW Cardiac arrests constitute a leading cause of mortality in the adult population and cardiologists are often tasked with the management of patients following cardiac arrest either as a consultant or primary provider in the cardiac intensive care unit. Familiarity with evidence-based practice for post-cardiac arrest care is a requisite for optimizing outcomes in this highly morbid group. This review will highlight important concepts necessary to managing these patients. RECENT FINDINGS Emerging evidence has further elucidated optimal care of post-arrest patients including timing for routine coronary angiography, utility of therapeutic hypothermia, permissive hypercapnia, and empiric aspiration pneumonia treatment. The complicated state of multi-organ failure following cardiac arrest needs to be carefully optimized by the clinician to prevent further neurologic injury and promote systemic recovery. Future studies should be aimed at understanding if these findings extend to specific patient populations, especially those at the highest risk for poor outcomes.
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Affiliation(s)
- Daniel Gonzalez
- Department of Medicine, Division of Cardiology, University of Minnesota, 420 Delaware St SE, MMC 508, Minneapolis, MN, 55455, USA
| | - Garima Dahiya
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Duke University, Durham, USA
| | | | | | - Gregory Mello
- University of Minnesota Medical School, Minneapolis, USA
| | - Rahul Singh
- Department of Medicine, Division of Cardiology, University of Minnesota, 420 Delaware St SE, MMC 508, Minneapolis, MN, 55455, USA
| | - Oladi Bentho
- Department of Neurology, University of Minnesota, Minneapolis, USA
| | - Andrea M Elliott
- Department of Medicine, Division of Cardiology, University of Minnesota, 420 Delaware St SE, MMC 508, Minneapolis, MN, 55455, USA.
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Aidiel L, Lim DZY, Chow KM, Ihsan M, Chia M, Choo HC. Precooling via immersion in CO 2-enriched water at 25°C decreased core body temperature but did not improve 10-km cycling time trial in the heat. Temperature (Austin) 2024; 11:123-136. [PMID: 38846527 PMCID: PMC11152097 DOI: 10.1080/23328940.2024.2302772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/31/2023] [Indexed: 06/09/2024] Open
Abstract
This study compared the effects of precooling via whole-body immersion in 25°C CO2-enriched water (CO2WI), 25°C unenriched water (WI) or no cooling (CON) on 10-km cycling time trial (TT) performance. After 30 min of precooling (CO2WI, CON, WI) in a randomized, crossover manner, 11 male cyclists/triathletes completed 30-min submaximal cycling (65%VO2peak), followed by 10-km TT in the heat (35°C, 65% relative humidity). Average power output and performance time during TT were similar between conditions (p = 0.387 to 0.833). Decreases in core temperature (Tcore) were greater in CO2WI (-0.54 ± 0.25°C) than in CON (-0.32 ± 0.09°C) and WI (-0.29 ± 0.20°C, p = 0.011 to 0.022). Lower Tcore in CO2WI versus CON was observed at 15th min of exercise (p = 0.050). Skin temperature was lower in CO2WI and WI than in CON during the exercise (p < 0.001 to 0.031). Only CO2WI (1029 ± 305 mL) decreased whole-body sweat loss compared with CON (1304 ± 246 mL, p = 0.029). Muscle oxygenation by near-infrared spectroscopy (NIRS), thermal sensation, and thermal comfort were lower in CO2WI and WI versus CON only during precooling (p < 0.001 to 0.041). NIRS-derived blood volume was significantly lower in CO2WI and WI versus CON during exercise (p < 0.001 to 0.022). Heart rate (p = 0.998) and rating of perceived exertion (p = 0.924) did not differ between conditions throughout the experiment. These results suggested that CO2WI maybe more effective than WI for enhanced core body cooling and minimized sweat losses.
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Affiliation(s)
- Luthfil Aidiel
- Sport Physiology Department, Sport Science and Medicine Centre, Singapore Sport Institute, Singapore
| | - Darren Z. Y. Lim
- National Institute of Education, Nanyang Technological University, Singapore
| | - Kin M. Chow
- Sport Physiology Department, Sport Science and Medicine Centre, Singapore Sport Institute, Singapore
| | | | - Michael Chia
- National Institute of Education, Nanyang Technological University, Singapore
| | - Hui C. Choo
- Sport Physiology Department, Sport Science and Medicine Centre, Singapore Sport Institute, Singapore
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11
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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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12
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Cujkevic-Plecko N, Rodriguez A, Anderson T, Rhodes J. Targeted temperature management and P btO 2 in traumatic brain injury. BRAIN & SPINE 2023; 3:102704. [PMID: 38105803 PMCID: PMC10724196 DOI: 10.1016/j.bas.2023.102704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/06/2023] [Accepted: 10/29/2023] [Indexed: 12/19/2023]
Abstract
Introduction Targeted Temperature Management (TTM) to normothermia is widely used in traumatic brain injury (TBI). We investigated the effects to of TTM to normothermia patients with TBI (GCS≤12) monitored with multimodality monitoring, to better understand the physiological consequences of this intervention. Research question In TBI patients cooled to normothermia and in which brain oxygenation deteriorates, are there changes in physiological parameters which are pertinent to brain oxygenation? Material and method 102 TBI patients with continuous recordings of intracranial pressure (ICP) and brain oxygen tension (PbtO2) were studied retrospectively. Non-continuous arterial carbon dioxide (PaCO2) and oxygen (PaO2) tensions, and core body temperature (Tc) were added. PaO2 and PaCO2 were also corrected for Tc. Transitions from elevated Tc to normothermia were identified in 39 patients. The 8 h pre and post the transition to normothermia were compared. Data is given as median [IQR] or mean (SD). Results Overall, normothermia reduced ICP (12 [9-18] -11 [8-17] mmHg, p < 0.009) and Tcore (38.3 [0.3]-36.9 [0.4] oC, p < 0.001), but not PbtO2 (23.3 [16.6]-24.4 [17.2-28.7] mmHg, NS). Normothermia was associated with a fall in PbtO2 in 18 patients (24.5 [9.3] -20.8 [7.6] mmHg). Only in those with a fall in PbtO2 with cooling did ICP (15 [10.8-18.5] -12 [7.8-17.3] mmHg, p = 0.002), and temperature corrected PaCO2 (5.3 [0.5]- 4.9 [0.8] kPa, p = 0.001) decrease. Discussion and conclusion A reduction in PbtO2 was only present in the subgroup of patients with a fall in temperature corrected PaCO2 with cooling. This suggests that even modest temperature changes could result in occult hyperventilation in some patients. pH stat correction of ventilation may be an important factor to consider in future TTM protocols.
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Affiliation(s)
| | | | - T. Anderson
- University of Edinburgh Department of Anaesthesia, Critical Care and Pain Medicine & NHS Lothian, UK
| | - J. Rhodes
- University of Edinburgh Department of Anaesthesia, Critical Care and Pain Medicine & NHS Lothian, UK
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13
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James S, Sanggaard S, Akif A, Mishra SK, Sanganahalli BG, Blumenfeld H, Verhagen JV, Hyder F, Herman P. Spatiotemporal features of neurovascular (un)coupling with stimulus-induced activity and hypercapnia challenge in cerebral cortex and olfactory bulb. J Cereb Blood Flow Metab 2023; 43:1891-1904. [PMID: 37340791 PMCID: PMC10676132 DOI: 10.1177/0271678x231183887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 06/22/2023]
Abstract
Carbon dioxide (CO2) is traditionally considered as metabolic waste, yet its regulation is critical for brain function. It is well accepted that hypercapnia initiates vasodilation, but its effect on neuronal activity is less clear. Distinguishing how stimulus- and CO2-induced vasodilatory responses are (dis)associated with neuronal activity has profound clinical and experimental relevance. We used an optical method in mice to simultaneously image fluorescent calcium (Ca2+) transients from neurons and reflectometric hemodynamic signals during brief sensory stimuli (i.e., hindpaw, odor) and CO2 exposure (i.e., 5%). Stimuli-induced neuronal and hemodynamic responses swiftly increased within locally activated regions exhibiting robust neurovascular coupling. However, hypercapnia produced slower global vasodilation which was temporally uncoupled to neuronal deactivation. With trends consistent across cerebral cortex and olfactory bulb as well as data from GCaMP6f/jRGECO1a mice (i.e., green/red Ca2+ fluorescence), these results unequivocally reveal that stimuli and CO2 generate comparable vasodilatory responses but contrasting neuronal responses. In summary, observations of stimuli-induced regional neurovascular coupling and CO2-induced global neurovascular uncoupling call for careful appraisal when using CO2 in gas mixtures to affect vascular tone and/or neuronal excitability, because CO2 is both a potent vasomodulator and a neuromodulator.
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Affiliation(s)
- Shaun James
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Simon Sanggaard
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Adil Akif
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Sandeep K Mishra
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | | | - Hal Blumenfeld
- Department of Neurology, Yale University, New Haven, CT, USA
- Department of Neuroscience, Yale University, New Haven, CT, USA
| | - Justus V Verhagen
- Department of Neuroscience, Yale University, New Haven, CT, USA
- John B. Pierce Laboratory, New Haven, CT, USA
| | - Fahmeed Hyder
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Peter Herman
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
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14
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Parmentier C, Ray S, Mazilescu LI, Kawamura M, Noguchi Y, Nogueira E, Ganesh S, Arulratnam B, Kalimuthu SN, Selzner M, Reichman TW. Normothermic Ex Vivo Machine Perfusion of Discarded Human Pancreas Allografts: A Feasibility Study. Transpl Int 2023; 36:10936. [PMID: 37252614 PMCID: PMC10210159 DOI: 10.3389/ti.2023.10936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 04/28/2023] [Indexed: 05/31/2023]
Abstract
Pancreas transplantation is the only curative treatment for patients with complicated diabetes, and organ shortage is a common and increasing problem. Strategies to expand the donor pool are needed, and normothermic ex vivo perfusion of the pancreas has the potential to test and repair grafts before implantation. Between January 2021 and April 2022, six human pancreases, declined for transplantation or islet isolation, were perfused using a previously established method by our group. All 6 cases were successfully perfused for 4 h, with minimal edema. The mean age of the donors was 44.16 ± 13.8 years. Five grafts were obtained from neurological death donors, and one was obtained from a donation after cardiac death. The mean glucose and lactate levels decreased throughout perfusion and insulin levels increased. All 6 grafts were metabolically active during perfusion and histopathology showed minimal tissue injury and no edema. Human normothermic ex vivo perfusion of the pancreas is feasible and safe and has the potential to expand the donor pool. Future studies will focus on tests and biomarkers for the assessment of grafts.
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Affiliation(s)
- Catherine Parmentier
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Samrat Ray
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Laura I. Mazilescu
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
- Essen University Hospital, Essen, North Rhine-Westphalia, Germany
| | - Masataka Kawamura
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Yuki Noguchi
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Emmanuel Nogueira
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Sujani Ganesh
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Bhranavi Arulratnam
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Sangeetha N. Kalimuthu
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Markus Selzner
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
| | - Trevor W. Reichman
- Toronto General Hospital, Toronto, ON, Canada
- University Health Network (UHN), Toronto, ON, Canada
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15
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Zhu B, Li H, Xie C, Sun M, Mai C, Xie Z, Wu Z, Zhang J, Nie L. Photoacoustic Microscopic Imaging of Cerebral Vessels for Intensive Monitoring of Metabolic Acidosis. Mol Imaging Biol 2023:10.1007/s11307-023-01815-8. [DOI: 10.1007/s11307-023-01815-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/23/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023]
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16
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Denchev K, Gomez J, Chen P, Rosenblatt K. Traumatic Brain Injury: Intraoperative Management and Intensive Care Unit Multimodality Monitoring. Anesthesiol Clin 2023; 41:39-78. [PMID: 36872007 DOI: 10.1016/j.anclin.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Traumatic brain injury is a devastating event associated with substantial morbidity. Pathophysiology involves the initial trauma, subsequent inflammatory response, and secondary insults, which worsen brain injury severity. Management entails cardiopulmonary stabilization and diagnostic imaging with targeted interventions, such as decompressive hemicraniectomy, intracranial monitors or drains, and pharmacological agents to reduce intracranial pressure. Anesthesia and intensive care requires control of multiple physiologic variables and evidence-based practices to reduce secondary brain injury. Advances in biomedical engineering have enhanced assessments of cerebral oxygenation, pressure, metabolism, blood flow, and autoregulation. Many centers employ multimodality neuromonitoring for targeted therapies with the hope to improve recovery.
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Affiliation(s)
- Krassimir Denchev
- Department of Anesthesiology, Wayne State University, 44555 Woodward Avenue, SJMO Medical Office Building, Suite 308, Pontiac, MI 48341, USA
| | - Jonathan Gomez
- Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Phipps 455, Baltimore, MD 21287, USA
| | - Pinxia Chen
- Department of Anesthesiology and Critical Care Medicine, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA 18015, USA
| | - Kathryn Rosenblatt
- Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Phipps 455, Baltimore, MD 21287, USA; Department of Neurology, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Phipps 455, Baltimore, MD 21287, USA.
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17
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Gültekin H, Güven M. Optic nerve sheath diameter, intensive care unit admission and COVID-19-related-in-hospital mortality. QJM 2023; 116:107-113. [PMID: 36259936 PMCID: PMC9619847 DOI: 10.1093/qjmed/hcac242] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Hypoxia and hypercapnia due to acute pulmonary failure in patients with coronavirus disease 2019 (COVID-19) can increase the intracranial pressure (ICP). ICP correlated with the optic nerve sheath diameter (ONSD) on ultrasonography and is associated with a poor prognosis. AIM We investigated the capability of ONSD measured during admission to the intensive care unit (ICU) in patients with critical COVID-19 in predicting in-hospital mortality. METHODS A total of 91 patients enrolled in the study were divided into two groups: survivor (n = 48) and nonsurvivor (n = 43) groups. ONSD was measured by ultrasonography within the first 3 h of ICU admission. RESULTS The median ONSD was higher in the nonsurvivor group than in the survivor group (5.95 mm vs. 4.15 mm, P < 0.001). The multivariate Cox proportional hazard regression analysis between ONSD and in-hospital mortality (contains 26 covariates) was significant (adjusted hazard ratio, 4.12; 95% confidence interval, 1.46-11.55; P = 0.007). The ONSD cutoff for predicting mortality during ICU admission was 5 mm (area under the curve, 0.985; sensitivity, 98%; and specificity, 90%). The median survival of patients with ONSD >5 mm (43%; n = 39) was lower than those with ONSD ≤5 mm (57%; n = 52) (11.5 days vs. 13.2 days; log-rank test P = 0.001). CONCLUSIONS ONSD ultrasonography during ICU admission may be an important, cheap and easy-to-apply method that can be used to predict mortality in the early period in patients with critical COVID-19.
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Affiliation(s)
- Hamza Gültekin
- Şırnak State Hospital, Department of Intensive Care Unit, 73000, Şırnak, Turkey
| | - Mehmet Güven
- Şırnak State Hospital, Department of Endocrinology and Metabolism, 73000, Şırnak, Turkey
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18
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Moghari L, Taghizadeh M, Soleimani A, Akbari H, Sharifi N. Dietary Acid Load and Predialysis Serum Bicarbonate Levels in Patients With End-Stage Renal Disease. J Ren Nutr 2023; 33:172-180. [PMID: 35597317 DOI: 10.1053/j.jrn.2022.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 03/08/2022] [Accepted: 05/01/2022] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVES Maintaining the predialysis serum bicarbonate at a recommended level is critical in patients undergoing hemodialysis. Therefore, the present study investigated the association between dietary acid load (DAL) and serum predialysis bicarbonate levels in patients with end-stage renal disease. METHODS Adult patients undergoing hemodialysis were enrolled in this cross-sectional study. Diet was assessed using a semiquantitative food frequency questionnaire. DAL was calculated with 2 validated indices: potential renal acid load (PRAL) and net endogenous acid production (NEAP). Values regarding predialysis serum bicarbonate level and serum electrolytes were obtained from the participant's medical records. The multiple linear regression analysis was used to determine the association between DAL indices and predialysis serum bicarbonate level. RESULTS The number of hemodialysis patients eligible for this study was 122. The participants' mean age and body mass index was 57.14 ± 3.8 years and 25.2 ± 4.9 kg/m2, respectively. About 65.6% of participants were male. The mean serum levels of predialysis bicarbonate were 21.59 ± 3.1 mEq/L. Also, 47.5% of patients had predialysis serum bicarbonate levels below the recommended value. The mean values of PRAL and NEAP were -2.8 ± 7.48 and 42.7 ± 10.1 mEq/day, respectively. PRAL significantly and inversely predicted predialysis serum bicarbonate level independent of covariates (standardized β = -0.38; P < .001). Also, NEAP was independently and inversely associated with predialysis bicarbonate level (standardized β = -0.40; P < .001). Consuming vegetables such as lettuce, tomato, cucumber, spinach, and dried fruits as well as low-fat milk, plain yogurt, and cream cheese were positively correlated to predialysis serum bicarbonate level. However, the canned tuna had a negative correlation with the predialysis serum bicarbonate. CONCLUSIONS The study's findings showed that the lower DAL was associated with higher predialysis serum bicarbonate levels in patients with end-stage renal disease. Due to the cross-sectional nature of the present study, prospective cohorts or well-controlled clinical trials are needed to confirm our result.
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Affiliation(s)
- Leila Moghari
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Basic Science Research Institute, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohsen Taghizadeh
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Basic Science Research Institute, Kashan University of Medical Sciences, Kashan, Iran
| | - Alireza Soleimani
- Department of Internal Medicine, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran
| | - Hossein Akbari
- Social Determinants of Health Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Nasrin Sharifi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Basic Science Research Institute, Kashan University of Medical Sciences, Kashan, Iran.
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19
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Wang S, Tang C, Liu Y, Border JJ, Roman RJ, Fan F. Impact of impaired cerebral blood flow autoregulation on cognitive impairment. FRONTIERS IN AGING 2022; 3:1077302. [PMID: 36531742 PMCID: PMC9755178 DOI: 10.3389/fragi.2022.1077302] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/23/2022] [Indexed: 11/16/2023]
Abstract
Although the causes of cognitive impairment are multifactorial, emerging evidence indicates that cerebrovascular dysfunction plays an essential role in dementia. One of the most critical aspects of cerebrovascular dysfunction is autoregulation of cerebral blood flow (CBF), mainly mediated by the myogenic response, which is often impaired in dementia individuals with comorbidities, such as diabetes and hypertension. However, many unsolved questions remain. How do cerebrovascular networks coordinately modulate CBF autoregulation in health and disease? Does poor CBF autoregulation have an impact on cognitive impairment, and what are the underlying mechanisms? This review summarizes the cerebral vascular structure and myogenic (a three-phase model), metabolic (O2, CO2, adenosine, and H+), and endothelial (shear stress) factors in the regulation of CBF; and the consequences of CBF dysautoregulation. Other factors contributing to cerebrovascular dysfunction, such as impaired functional hyperemia and capillary abnormalities, are included as well. Moreover, this review highlights recent studies from our lab in terms of novel mechanisms involved in CBF autoregulation and addresses a hypothesis that there is a three-line of defense for CBF autoregulation in the cerebral vasculature.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Chengyun Tang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States
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20
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Arterial Carbon Dioxide and Acute Brain Injury in Venoarterial Extracorporeal Membrane Oxygenation. ASAIO J 2022; 68:1501-1507. [PMID: 35671442 PMCID: PMC9477972 DOI: 10.1097/mat.0000000000001699] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Acute brain injury (ABI) occurs frequently in patients receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO). We examined the association between peri-cannulation arterial carbon dioxide tension (PaCO 2 ) and ABI with granular blood gas data. We retrospectively analyzed adult patients who underwent VA-ECMO at a tertiary care center with standardized neuromonitoring. Pre- and post-cannulation PaCO 2 were defined as the mean of all PaCO 2 values in the 12 hours before and after cannulation, respectively. Peri-cannulation PaCO 2 drop (∆PaCO 2 ) equaled pre- minus post-cannulation PaCO 2 . ABI included intracranial hemorrhage (ICH), ischemic stroke, hypoxic-ischemic brain injury, cerebral edema, seizure, and brain death. Univariable logistic regression analysis was performed for the presence of ABI. Out of 129 VA-ECMO patients (median age = 60, 63% male), 43 (33%) patients experienced ABI. Patients had a median of 11 (interquartile range: 8-14) peri-cannulation PaCO 2 values. Comparing patients with and without ABI, pre-cannulation (39 vs. 42 mm Hg; p = 0.38) and post-cannulation (37 vs. 36 mm Hg; p = 0.82) PaCO 2 were not different. However, higher pre-cannulation PaCO 2 (odds ratio [OR] = 2.10; 95% confidence interval [CI] = 1.10-4.00; p = 0.02) and larger ∆PaCO 2 (OR = 2.69; 95% CI = 1.18-6.13; p = 0.02) were associated with ICH. In conclusion, in a cohort with granular arterial blood gas (ABG) data and a standardized neuromonitoring protocol, higher pre-cannulation PaCO 2 and larger ∆PaCO 2 were associated with increased prevalence of ICH.
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21
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Zadek F, Giudici G, Ferraris Fusarini C, Ambrosini MT, di Modugno A, Scaravilli V, Zanella A, Fumagalli R, Stocchetti N, Calderini E, Langer T. Cerebrospinal fluid and arterial acid-base equilibria in spontaneously breathing third-trimester pregnant women. Br J Anaesth 2022; 129:726-733. [PMID: 36096944 PMCID: PMC9642833 DOI: 10.1016/j.bja.2022.07.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/17/2022] [Accepted: 07/10/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Acid-base status in full-term pregnant women is characterised by hypocapnic alkalosis. Whether this respiratory alkalosis is primary or consequent to changes in CSF electrolytes is not clear. METHODS We enrolled third-trimester pregnant women (pregnant group) and healthy, non-pregnant women of childbearing age (controls) undergoing spinal anaesthesia for Caesarean delivery and elective surgery, respectively. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide ( [Formula: see text] ), and pH were measured in simultaneously collected CSF and arterial blood samples. RESULTS All pregnant women (20) were hypocapnic, whilst only four (30%) of the controls (13) had an arterial [Formula: see text] <4.7 kPa (P<0.001). The incidence of hypocapnic alkalosis was higher in the pregnant group (65% vs 8%; P=0.001). The CSF-to-plasma Pco2 difference was significantly higher in pregnant women (1.5 [0.3] vs 1.0 [0.4] kPa; P<0.001), mainly because of a decrease in arterial Pco2 (3.9 [0.3] vs 4.9 [0.5] kPa; P<0.001). Similarly, the CSF-to-plasma difference in SID was less negative in pregnant women (-7.8 [1.4] vs -11.4 [2.3] mM; P<0.001), mainly because of a decreased arterial SID (31.5 [1.2] vs 36.1 [1.9] mM; P<0.001). The major determinant of the reduced plasma SID of pregnant women was a relative increase in plasma chloride compared with sodium. CONCLUSIONS Primary hypocapnic alkalosis characterises third-trimester pregnant women leading to chronic acid-base adaptations of CSF and plasma. The compensatory SID reduction, mainly sustained by an increase in chloride concentration, is more pronounced in plasma than in CSF, as the decrease in Pco2 is more marked in this compartment. CLINICAL TRIAL REGISTRATION NCT03496311.
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Affiliation(s)
- Francesco Zadek
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy
| | - Giorgio Giudici
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | | | - Maria T. Ambrosini
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Adriana di Modugno
- Central Laboratory, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Vittorio Scaravilli
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy,Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Alberto Zanella
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy,Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberto Fumagalli
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy,Department of Anesthesia and Intensive Care Medicine, Niguarda Ca’ Granda, Milan, Italy
| | - Nino Stocchetti
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy,Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Edoardo Calderini
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Thomas Langer
- Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy,Department of Anesthesia and Intensive Care Medicine, Niguarda Ca’ Granda, Milan, Italy,Corresponding author.
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22
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Drew PJ. Neurovascular coupling: motive unknown. Trends Neurosci 2022; 45:809-819. [PMID: 35995628 PMCID: PMC9768528 DOI: 10.1016/j.tins.2022.08.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 12/13/2022]
Abstract
In the brain, increases in neural activity drive changes in local blood flow via neurovascular coupling. The common explanation for increased blood flow (known as functional hyperemia) is that it supplies the metabolic needs of active neurons. However, there is a large body of evidence that is inconsistent with this idea. Baseline blood flow is adequate to supply oxygen needs even with elevated neural activity. Neurovascular coupling is irregular, absent, or inverted in many brain regions, behavioral states, and conditions. Increases in respiration can increase brain oxygenation without flow changes. Simulations show that given the architecture of the brain vasculature, areas of low blood flow are inescapable and cannot be removed by functional hyperemia. As discussed in this article, potential alternative functions of neurovascular coupling include supplying oxygen for neuromodulator synthesis, brain temperature regulation, signaling to neurons, stabilizing and optimizing the cerebral vascular structure, accommodating the non-Newtonian nature of blood, and driving the production and circulation of cerebrospinal fluid (CSF).
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Affiliation(s)
- Patrick J Drew
- Center for Neural Engineering, Departments of Engineering Science and Mechanics, Neurosurgery, Biology, and Biomedical Engineering, The Pennsylvania State University, W-317 Millennium Science Complex, University Park, PA 16802, USA.
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23
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Association Between Early Change in Arterial Carbon Dioxide Tension and Outcomes in Neonates Treated by Extracorporeal Membrane Oxygenation. ASAIO J 2022; 69:411-416. [PMID: 36730940 PMCID: PMC10044589 DOI: 10.1097/mat.0000000000001838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The primary objective was to investigate the association between partial pressure of carbon dioxide (PaCO2) change after extracorporeal membrane oxygenation (ECMO) initiation and neurologic outcome in neonates treated for respiratory failure. A retrospective analysis of the Extracorporeal Life Support Organization (ELSO) database including newborns supported by ECMO for respiratory indication during 2015-2020. The closest Pre-ECMO (Pre-ECMO PaCO2) and at 24 hours after ECMO initiation (H24 PaCO2) PaCO2 values allowed to calculate the relative change in PaCO2 (Rel Δ PaCO2 = [H24 PaCO2 - Pre-ECMO PaCO2]/Pre-ECMO PaCO2). The primary outcome was the onset of any acute neurologic event (ANE), defined as cerebral bleeding, ischemic stroke, clinical or electrical seizure, or brain death during ECMO. We included 3,583 newborns (median age 1 day [interquartile range {IQR}, 1-3], median weight 3.2 kg [IQR, 2.8-3.6]) from 198 ELSO centers. The median Rel Δ PaCO2 value was -29.9% [IQR, -46.2 to -8.5]. Six hundred nine (17%) of them had ANE (405 cerebral bleedings, 111 ischemic strokes, 225 seizures, and 6 brain deaths). Patients with a decrease of PaCO2 > 50% were more likely to develop ANE than others (odds ratio [OR] 1.78, 95% confidence interval [CI], 1.31-2.42, p < 0.001). This was still observed after adjustment for all clinically relevant confounding factors (adjusted OR 1.94, 95% CI, 1.29-2.92, p = 0.001). A significant decrease in PaCO2 after ECMO start is associated with ANE among neonates requiring ECMO for respiratory failure. Cautious PaCO2 decrease should be considered after start of ECMO therapy.
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24
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Alharbi AAD, Iwamoto N, Ebine N, Nakae S, Hojo T, Fukuoka Y. The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans. Nutrients 2022; 14:nu14193974. [PMID: 36235628 PMCID: PMC9571546 DOI: 10.3390/nu14193974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/23/2022] Open
Abstract
This research examined the effects of single-dose molecular hydrogen (H2) supplements on acid-base status and local muscle deoxygenation during rest, high-intensity intermittent training (HIIT) performance, and recovery. Ten healthy, trained subjects in a randomized, double-blind, crossover design received H2-rich calcium powder (HCP) (1500 mg, containing 2.544 μg of H2) or H2-depleted placebo (1500 mg) supplements 1 h pre-exercise. They performed six bouts of 7 s all-out pedaling (HIIT) at 7.5% of body weight separated by 40 s pedaling intervals, followed by a recovery period. Blood gases’ pH, PCO2, and HCO3− concentrations were measured at rest. Muscle deoxygenation (deoxy[Hb + Mb]) and tissue O2 saturation (StO2) were determined via time-resolved near-infrared spectroscopy in the vastus lateralis (VL) and rectus femoris (RF) muscles from rest to recovery. At rest, the HCP group had significantly higher PCO2 and HCO3− concentrations and a slight tendency toward acidosis. During exercise, the first HIIT bout’s peak power was significantly higher in HCP (839 ± 112 W) vs. Placebo (816 ± 108 W, p = 0.001), and HCP had a notable effect on significantly increased deoxy[Hb + Mb] concentration during HIIT exercise, despite no differences in heart rate response. The HCP group showed significantly greater O2 extraction in VL and microvascular (Hb) volume in RF during HIIT exercise. The HIIT exercise provided significantly improved blood flow and muscle reoxygenation rates in both the RF and VL during passive recovery compared to rest in all groups. The HCP supplement might exert ergogenic effects on high-intensity exercise and prove advantageous for improving anaerobic HIIT exercise performance.
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Affiliation(s)
| | - Noriaki Iwamoto
- Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0396, Japan
| | - Naoyuki Ebine
- Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0396, Japan
| | - Satoshi Nakae
- Human Augmentation Research Center, National Institute of Advanced Industrial Science and Technology, Kashiwa II Campus, The University of Tokyo, Chiba 277-0882, Japan
| | - Tatsuya Hojo
- Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0396, Japan
| | - Yoshiyuki Fukuoka
- Graduate School of Health and Sports Science, Doshisha University, Kyoto 610-0396, Japan
- Correspondence: ; Tel.: +81-774-65-7530; Fax: +81-774-65-6029
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25
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Kojima S, Morishita S, Hotta K, Qin W, Usui N, Tsubaki A. Temporal changes in cortical oxygenation in the motor-related areas and bilateral prefrontal cortex based on exercise intensity and respiratory metabolism during incremental exercise in male subjects: A near-Infrared spectroscopy study. Front Physiol 2022; 13:794473. [PMID: 36017334 PMCID: PMC9396126 DOI: 10.3389/fphys.2022.794473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
A recent study has reported that prefrontal cortex (PFC) activity during incremental exercise may be related to exercise termination on exhaustion. However, few studies have focused on motor-related areas during incremental exercise. This study investigated changes in the oxygenation of the PFC and motor-related areas using near-infrared spectroscopy during incremental exercise. Moreover, we analyzed the effect of exercise termination on changes in cortical oxygenation based on exercise intensity and respiratory metabolism. Sixteen healthy young male patients participated in this study. After a 4-min rest and 4-min warm-up period, incremental exercise was started at an incremental load corresponding to 20 W/min. Oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), and total hemoglobin (THb) in the bilateral PFC, supplementary motor area, and primary motor cortex were measured. We evaluated changes in oxygenation in each cortex before and after the anaerobic threshold (AT) and respiratory compensation point to identify changes due to respiratory metabolism. O2Hb and THb increased from moderate intensity or after AT to maximal exercise, and HHb increased slowly compared to O2Hb and THb; these changes in hemoglobin levels were consistent in all cortical areas we measured. However, the increase in each hemoglobin level in the bilateral PFC during incremental exercise was faster than that in motor-related areas. Moreover, changes in cortical oxygenation in the right PFC were faster than those in the left PFC. These results suggest changes based on differences in neural activity due to the cortical area.
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Affiliation(s)
- Sho Kojima
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- Department of Physical Therapy, Kisen Hospital, Tokyo, Japan
| | | | - Kazuki Hotta
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - Weixiang Qin
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - Naoto Usui
- Department of Physical Therapy, Kisen Hospital, Tokyo, Japan
| | - Atsuhiro Tsubaki
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
- *Correspondence: Atsuhiro Tsubaki,
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26
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Vestergaard MB, Frederiksen JL, Larsson HBW, Cramer SP. Cerebrovascular Reactivity and Neurovascular Coupling in Multiple Sclerosis-A Systematic Review. Front Neurol 2022; 13:912828. [PMID: 35720104 PMCID: PMC9198441 DOI: 10.3389/fneur.2022.912828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
The inflammatory processes observed in the central nervous system in multiple sclerosis (MS) could damage the endothelium of the cerebral vessels and lead to a dysfunctional regulation of vessel tonus and recruitment, potentially impairing cerebrovascular reactivity (CVR) and neurovascular coupling (NVC). Impaired CVR or NVC correlates with declining brain health and potentially plays a causal role in the development of neurodegenerative disease. Therefore, we examined studies on CVR or NVC in MS patients to evaluate the evidence for impaired cerebrovascular function as a contributing disease mechanism in MS. Twenty-three studies were included (12 examined CVR and 11 examined NVC). Six studies found no difference in CVR response between MS patients and healthy controls. Five studies observed reduced CVR in patients. This discrepancy can be because CVR is mainly affected after a long disease duration and therefore is not observed in all patients. All studies used CO2 as a vasodilating stimulus. The studies on NVC demonstrated diverse results; hence a conclusion that describes all the published observations is difficult to find. Future studies using quantitative techniques and larger study samples are needed to elucidate the discrepancies in the reported results.
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Affiliation(s)
- Mark B Vestergaard
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
| | - Jette L Frederiksen
- Danish Multiple Sclerosis Center, Department of Neurology, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Henrik B W Larsson
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark.,Danish Multiple Sclerosis Center, Department of Neurology, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
| | - Stig P Cramer
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
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27
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Császár E, Lénárt N, Cserép C, Környei Z, Fekete R, Pósfai B, Balázsfi D, Hangya B, Schwarcz AD, Szabadits E, Szöllősi D, Szigeti K, Máthé D, West BL, Sviatkó K, Brás AR, Mariani JC, Kliewer A, Lenkei Z, Hricisák L, Benyó Z, Baranyi M, Sperlágh B, Menyhárt Á, Farkas E, Dénes Á. Microglia modulate blood flow, neurovascular coupling, and hypoperfusion via purinergic actions. J Exp Med 2022; 219:213035. [PMID: 35201268 PMCID: PMC8932534 DOI: 10.1084/jem.20211071] [Citation(s) in RCA: 79] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/28/2021] [Accepted: 01/03/2022] [Indexed: 12/13/2022] Open
Abstract
Microglia, the main immunocompetent cells of the brain, regulate neuronal function, but their contribution to cerebral blood flow (CBF) regulation has remained elusive. Here, we identify microglia as important modulators of CBF both under physiological conditions and during hypoperfusion. Microglia establish direct, dynamic purinergic contacts with cells in the neurovascular unit that shape CBF in both mice and humans. Surprisingly, the absence of microglia or blockade of microglial P2Y12 receptor (P2Y12R) substantially impairs neurovascular coupling in mice, which is reiterated by chemogenetically induced microglial dysfunction associated with impaired ATP sensitivity. Hypercapnia induces rapid microglial calcium changes, P2Y12R-mediated formation of perivascular phylopodia, and microglial adenosine production, while depletion of microglia reduces brain pH and impairs hypercapnia-induced vasodilation. Microglial actions modulate vascular cyclic GMP levels but are partially independent of nitric oxide. Finally, microglial dysfunction markedly impairs P2Y12R-mediated cerebrovascular adaptation to common carotid artery occlusion resulting in hypoperfusion. Thus, our data reveal a previously unrecognized role for microglia in CBF regulation, with broad implications for common neurological diseases.
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Affiliation(s)
- Eszter Császár
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Nikolett Lénárt
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Zsuzsanna Környei
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Rebeka Fekete
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Pósfai
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Diána Balázsfi
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Anett D Schwarcz
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Eszter Szabadits
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Dávid Szöllősi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Domokos Máthé
- Hungarian Centre of Excellence for Molecular Medicine, Szeged, Hungary
| | | | - Katalin Sviatkó
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Ana Rita Brás
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Jean-Charles Mariani
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - Andrea Kliewer
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - Zsolt Lenkei
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - László Hricisák
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltán Benyó
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Mária Baranyi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ákos Menyhárt
- Hungarian Centre of Excellence for Molecular Medicine, University of Szeged, Cerebral Blood Flow and Metabolism Research Group, Szeged, Hungary.,Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Hungarian Centre of Excellence for Molecular Medicine, University of Szeged, Cerebral Blood Flow and Metabolism Research Group, Szeged, Hungary.,Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám Dénes
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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28
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Liu S, Bilston LE, Flores Rodriguez N, Wright C, McMullan S, Lloyd R, Stoodley MA, Hemley SJ. Changes in intrathoracic pressure, not arterial pulsations, exert the greatest effect on tracer influx in the spinal cord. Fluids Barriers CNS 2022; 19:14. [PMID: 35135574 PMCID: PMC8822685 DOI: 10.1186/s12987-022-00310-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/21/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Cerebrospinal fluid (CSF) circulation in the brain has garnered considerable attention in recent times. In contrast, there have been fewer studies focused on the spine, despite the expected importance of CSF circulation in disorders specific to the spine, including syringomyelia. The driving forces that regulate spinal CSF flow are not well defined and are likely to be different to the brain given the anatomical differences and proximity to the heart and lungs. The aims of this study were to determine the effects of heart rate, blood pressure and respiration on the distribution of CSF tracers in the spinal subarachnoid space, as well as into the spinal cord interstitium. METHODS In Sprague Dawley rats, physiological parameters were manipulated such that the effects of spontaneous breathing (generating alternating positive and negative intrathoracic pressures), mechanical ventilation (positive intrathoracic pressure only), tachy/bradycardia, as well as hyper/hypotension were separately studied. To investigate spinal CSF hydrodynamics, in vivo near-infrared imaging of intracisternally infused indocyanine green was performed. CSF tracer transport was further characterised with in vivo two-photon intravital imaging. Tracer influx at a microscopic level was quantitatively characterised by ex vivo epifluorescence imaging of fluorescent ovalbumin. RESULTS Compared to mechanically ventilated controls, spontaneous breathing animals had significantly greater movement of tracer in the subarachnoid space. There was also greater influx into the spinal cord interstitium. Hypertension and tachycardia had no significant effect on spinal subarachnoid spinal CSF tracer flux and exerted less effect than respiration on tracer influx into the spinal cord. CONCLUSIONS Intrathoracic pressure changes that occur over the respiratory cycle, particularly decreased intrathoracic pressures generated during inspiration, have a profound effect on tracer movement after injection into spinal CSF and increase cord parenchymal tracer influx. Arterial pulsations likely drive fluid transport from perivascular spaces into the surrounding interstitium, but their overall impact is less than that of the respiratory cycle on net tracer influx.
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Affiliation(s)
- Shinuo Liu
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2031, Australia
| | - Neftali Flores Rodriguez
- Sydney Microscopy and Microanalysis, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Courtney Wright
- Sydney Microscopy and Microanalysis, Brain and Mind Centre, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Simon McMullan
- Department of Biological Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Robert Lloyd
- Neuroscience Research Australia, Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2031, Australia
| | - Marcus A Stoodley
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Sarah J Hemley
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia.
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29
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Fan JL, Fisher JP. Probing shear-stress mediated cerebral vasodilatation in humans - it's a NO brainer. J Physiol 2022; 600:1283-1284. [PMID: 35001389 PMCID: PMC9303707 DOI: 10.1113/jp282707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jui-Lin Fan
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
| | - James P Fisher
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, New Zealand
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30
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Volynsky MA, Mamontov OV, Osipchuk AV, Zaytsev VV, Sokolov AY, Kamshilin AA. Study of cerebrovascular reactivity to hypercapnia by imaging photoplethysmography to develop a method for intraoperative assessment of the brain functional reserve. BIOMEDICAL OPTICS EXPRESS 2022; 13:184-196. [PMID: 35154863 PMCID: PMC8803018 DOI: 10.1364/boe.443477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/07/2021] [Accepted: 11/29/2021] [Indexed: 05/03/2023]
Abstract
Intraoperative assessment of cerebrovascular reactivity is a relevant problem of neurosurgery. To assess the functional reserve of cerebral blood flow, we suggest using imaging photoplethysmography for measuring changes in cortical perfusion caused by CO2 inhalation. Feasibility of the technique was demonstrated in three groups of anesthetized rats (n=21) with opened and closed cranial windows. Our study for the first time revealed that the hemodynamic response to hypercapnia strongly depends on the cranial state. However, it was shown that regardless of the direction of changes in local and systemic hemodynamics, the ratio of normalized changes in arterial blood pressure and cortical perfusion could be used as a measure of the cerebrovascular functional reserve.
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Affiliation(s)
- Maxim A. Volynsky
- School of Physics and Engineering, ITMO University, 49 Kronverksky av., 197101 St. Petersburg, Russia
- Laboratory of New Functional Materials for Photonics, Institute of Automation & Control Processes of the Far East Branch of the Russian Academy of Sciences, 5, Radio str., 690041 Vladivostok, Russia
- These authors contributed equally to this work
| | - Oleg V. Mamontov
- Laboratory of New Functional Materials for Photonics, Institute of Automation & Control Processes of the Far East Branch of the Russian Academy of Sciences, 5, Radio str., 690041 Vladivostok, Russia
- Department of Circulation Physiology, Almazov National Medical Research Centre, 2 Akkuratov str., 197341 St. Petersburg, Russia
- These authors contributed equally to this work
| | - Anastasiia V. Osipchuk
- Department of Neuropharmacology, Valdman Institute of Pharmacology, Pavlov First Saint Petersburg State Medical University, 6-8 Lev Tolstoy str., 197022 St. Petersburg, Russia
| | - Valery V. Zaytsev
- Laboratory of New Functional Materials for Photonics, Institute of Automation & Control Processes of the Far East Branch of the Russian Academy of Sciences, 5, Radio str., 690041 Vladivostok, Russia
- Department of Circulation Physiology, Almazov National Medical Research Centre, 2 Akkuratov str., 197341 St. Petersburg, Russia
| | - Alexey Y. Sokolov
- Department of Neuropharmacology, Valdman Institute of Pharmacology, Pavlov First Saint Petersburg State Medical University, 6-8 Lev Tolstoy str., 197022 St. Petersburg, Russia
- Laboratory of Cortico-Visceral Physiology, Pavlov Institute of Physiology of the Russian Academy of Sciences, 6 Makarov emb., 199034 St. Petersburg, Russia
| | - Alexei A. Kamshilin
- Laboratory of New Functional Materials for Photonics, Institute of Automation & Control Processes of the Far East Branch of the Russian Academy of Sciences, 5, Radio str., 690041 Vladivostok, Russia
- Department of Circulation Physiology, Almazov National Medical Research Centre, 2 Akkuratov str., 197341 St. Petersburg, Russia
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31
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De Wachter J, Proost M, Habay J, Verstraelen M, Díaz-García J, Hurst P, Meeusen R, Van Cutsem J, Roelands B. Prefrontal Cortex Oxygenation During Endurance Performance: A Systematic Review of Functional Near-Infrared Spectroscopy Studies. Front Physiol 2021; 12:761232. [PMID: 34764885 PMCID: PMC8576380 DOI: 10.3389/fphys.2021.761232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/27/2021] [Indexed: 01/17/2023] Open
Abstract
Introduction: A myriad of factors underlie pacing-/exhaustion-decisions that are made during whole-body endurance performance. The prefrontal cortex (PFC) is a brain region that is crucial for decision-making, planning, and attention. PFC oxygenation seems to be a mediating factor of performance decisions during endurance performance. Nowadays, there is no general overview summarizing the current knowledge on how PFC oxygenation evolves during whole-body endurance performance and whether this is a determining factor. Methods: Three electronic databases were searched for studies related to the assessment of PFC oxygenation, through near-IR spectroscopy (NIRS), during endurance exercise. To express PFC oxygenation, oxygenated (HbO2) and deoxygenated hemoglobin (HHb) concentrations were the primary outcome measures. Results: Twenty-eight articles were included. Ten articles focused on assessing prefrontal oxygenation through a maximal incremental test (MIT) and 18 focused on using endurance tasks at workloads ranging from low intensity to supramaximal intensity. In four MIT studies measuring HbO2, an increase of HbO2 was noticed at the respiratory compensation point (RCP), after which it decreased. HbO2 reached a steady state in the four studies and increased in one study until exhaustion. All studies found a decrease or steady state in HHb from the start until RCP and an increase to exhaustion. In regard to (non-incremental) endurance tasks, a general increase in PFC oxygenation was found while achieving a steady state at vigorous intensities. PCF deoxygenation was evident for near-to-maximal intensities at which an increase in oxygenation and the maintenance of a steady state could not be retained. Discussion/Conclusion: MIT studies show the presence of a cerebral oxygenation threshold (ThCox) at RCP. PFC oxygenation increases until the RCP threshold, thereafter, a steady state is reached and HbO2 declines. This study shows that the results obtained from MIT are transferable to non-incremental endurance exercise. HbO2 increases during low-intensity and moderate-intensity until vigorous-intensity exercise, and it reaches a steady state in vigorous-intensity exercise. Furthermore, ThCox can be found between vigorous and near-maximal intensities. During endurance exercise at near-maximal intensities, PFC oxygenation increases until the value exceeding this threshold, resulting in a decrease in PFC oxygenation. Future research should aim at maintaining and improving PFC oxygenation to help in improving endurance performance and to examine whether PFC oxygenation has a role in other performance-limiting factors.
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Affiliation(s)
- Jonas De Wachter
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Matthias Proost
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jelle Habay
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Matthias Verstraelen
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jesús Díaz-García
- Faculty of Sport Sciences, University of Extremadura, Caceres, Spain
| | - Philip Hurst
- The School of Psychology & Life Sciences, Canterbury Christ Church University, Canterbury, United Kingdom
| | - Romain Meeusen
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jeroen Van Cutsem
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium.,VIPER Research Unit, Royal Military Academy, Brussels, Belgium
| | - Bart Roelands
- Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
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32
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Dynamics of cortical oxygenation during immediate adaptation to extrauterine life. Sci Rep 2021; 11:22041. [PMID: 34764396 PMCID: PMC8586152 DOI: 10.1038/s41598-021-01674-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/02/2021] [Indexed: 11/09/2022] Open
Abstract
The neonatal transition involves physiological modifications as a consequence of the complexity of the perinatal period. Various strategies can be used to attain the same level of postnatal cerebral oxygenation, depending on the status of the infant at birth. We evaluated such strategies by recording 20 full-term newborns by near-infrared spectroscopy during the first 10 min of life. The acid–base status at birth revealed two clustered profiles of cerebral oxygenation dynamics. Lower pH and base excess and higher lactate levels were associated with more rapid attainment of the 95% maximal tissue oxygenation index value. These results suggest that metabolic mechanisms drive initial cerebral oxygenation dynamics during this critical period. These results confirm the capacity of newborns to develop multiple strategies to protect the brain.
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33
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Caldwell HG, Carr JMJR, Minhas JS, Swenson ER, Ainslie PN. Acid-base balance and cerebrovascular regulation. J Physiol 2021; 599:5337-5359. [PMID: 34705265 DOI: 10.1113/jp281517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/19/2021] [Indexed: 12/22/2022] Open
Abstract
The regulation and defence of intracellular pH is essential for homeostasis. Indeed, alterations in cerebrovascular acid-base balance directly affect cerebral blood flow (CBF) which has implications for human health and disease. For example, changes in CBF regulation during acid-base disturbances are evident in conditions such as chronic obstructive pulmonary disease and diabetic ketoacidosis. The classic experimental studies from the past 75+ years are utilized to describe the integrative relationships between CBF, carbon dioxide tension (PCO2 ), bicarbonate (HCO3 - ) and pH. These factors interact to influence (1) the time course of acid-base compensatory changes and the respective cerebrovascular responses (due to rapid exchange kinetics between arterial blood, extracellular fluid and intracellular brain tissue). We propose that alterations in arterial [HCO3 - ] during acute respiratory acidosis/alkalosis contribute to cerebrovascular acid-base regulation; and (2) the regulation of CBF by direct changes in arterial vs. extravascular/interstitial PCO2 and pH - the latter recognized as the proximal compartment which alters vascular smooth muscle cell regulation of CBF. Taken together, these results substantiate two key ideas: first, that the regulation of CBF is affected by the severity of metabolic/respiratory disturbances, including the extent of partial/full acid-base compensation; and second, that the regulation of CBF is independent of arterial pH and that diffusion of CO2 across the blood-brain barrier is integral to altering perivascular extracellular pH. Overall, by realizing the integrative relationships between CBF, PCO2 , HCO3 - and pH, experimental studies may provide insights to improve CBF regulation in clinical practice with treatment of systemic acid-base disorders.
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Affiliation(s)
- Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
| | - Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Erik R Swenson
- Pulmonary, Critical Care and Sleep Medicine Division, University of Washington, and VA Puget Sound Healthcare System, Seattle, WA, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
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34
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Joram N, Beqiri E, Pezzato S, Andrea M, Robba C, Liet JM, Chenouard A, Bourgoin P, Czosnyka M, Léger PL, Smielewski P. Impact of Arterial Carbon Dioxide and Oxygen Content on Cerebral Autoregulation Monitoring Among Children Supported by ECMO. Neurocrit Care 2021; 35:480-490. [PMID: 33686559 DOI: 10.1007/s12028-021-01201-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/29/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Cerebral autoregulation (CA) impairment is associated with neurological complications among children supported by extracorporeal membrane oxygenation (ECMO). Severe variations of arterial CO2 (PaCO2) and O2 (PaO2) tension after ECMO onset are common and associate with mortality and poor neurological outcome. The impact of gas exchange on CA among critically ill patients is poorly studied. METHODS Retrospective analysis of data collected prospectively from 30 children treated with veno-arterial or veno-venous ECMO in the PICU of Nantes University Hospital, France. A correlation coefficient between the variations of regional cerebral oxygen saturation (rSO2) and the variations of mean arterial blood pressure (MAP) was calculated as an index of CA (cerebral oxygenation reactivity index, COx). Cox-MAP plots were investigated allowing determining lower limit of autoregulation (LLA) and upper limit of autoregulation (ULA) limits of autoregulation. Age-based normal blood pressure was used to adjust the MAP, LLA, and ULA data from each patient and then reported as percentage (nMAP, nLLA, and nULA, respectively). RSO2, COx, nMAP, nLLA, and nULA values were averaged over one hour before each arterial blood gas (ABG) sample during ECMO run. RESULTS Thirty children (median age 4.8 months [Interquartile range (IQR) 0.7-39.1], median weight 5 kg [IQR 4-15]) experiencing 31 ECMO runs were included in the study. Three hundred and ninety ABGs were analyzed. The highest values of COx were observed on day 1 (D1) of ECMO. The relationship between COx and PaCO2 was nonlinear, but COx values tended to be lower in case of hypercapnia compared to normocapnia. During the whole ECMO run, a weak but significant correlation between PaCO2 and nULA was observed (R = 0.432, p = 0.02). On D1 of ECMO, this correlation was stronger (R = 0.85, p = 0.03) and a positive correlation between nLLA and PaCO2 was also found (R = 0.726, p < 0.001). A very weak negative correlation between PaO2 and nULA was observed within the whole ECMO run and on D1 of ECMO (R = -0.07 p = 0.04 and R = -0.135 p = <0.001, respectively). The difference between nULA and nLLA representing the span of the autoregulation plateau was positively correlated with PaCO2 and negatively correlated with PaO2 (R = 0.224, p = 0.01 and R = -0.051, p = 0.004, respectively). CONCLUSIONS We observed a complex relationship between PaCO2 and CA, influenced by the level of blood pressure. Hypercapnia seems to be globally protective in normotensive or hypertensive condition, while, in case of very low MAP, hypercapnia may disturb CA as it increases LLA. These data add additional arguments for very cautiously lower PaCO2, especially after ECMO start.
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Affiliation(s)
- Nicolas Joram
- Pediatric Intensive Care Unit, University Hospital of Nantes, Nantes, France. .,Clinical Investigation Center (CIC) 1413, University Hospital of Nantes, Nantes, France. .,INSERM U955-ENVA, University Paris 12, Paris, France.
| | - Erta Beqiri
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Department of Physiology and Transplantation, Milan University, Milan, Italy
| | - Stefano Pezzato
- Pediatric Intensive Care Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy
| | - Moscatelli Andrea
- Pediatric Intensive Care Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy
| | - Chiara Robba
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Policlinico San Martino IRCCS for Oncology and Neuroscience, Genova, Italy
| | - Jean-Michel Liet
- Pediatric Intensive Care Unit, University Hospital of Nantes, Nantes, France.,Clinical Investigation Center (CIC) 1413, University Hospital of Nantes, Nantes, France
| | - Alexis Chenouard
- Pediatric Intensive Care Unit, University Hospital of Nantes, Nantes, France.,Clinical Investigation Center (CIC) 1413, University Hospital of Nantes, Nantes, France
| | - Pierre Bourgoin
- Pediatric Intensive Care Unit, University Hospital of Nantes, Nantes, France.,Clinical Investigation Center (CIC) 1413, University Hospital of Nantes, Nantes, France
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Pierre-Louis Léger
- INSERM U955-ENVA, University Paris 12, Paris, France.,Pediatric Intensive Care Unit, Trousseau University Hospital, Paris, France
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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35
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Tsai CJ, Nagata T, Liu CY, Suganuma T, Kanda T, Miyazaki T, Liu K, Saitoh T, Nagase H, Lazarus M, Vogt KE, Yanagisawa M, Hayashi Y. Cerebral capillary blood flow upsurge during REM sleep is mediated by A2a receptors. Cell Rep 2021; 36:109558. [PMID: 34407410 DOI: 10.1016/j.celrep.2021.109558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/05/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022] Open
Abstract
Sleep is generally viewed as a period of recovery, but how the supply of cerebral blood flow (CBF) changes across sleep/wake states has remained unclear. Here, we directly observe red blood cells (RBCs) within capillaries, where the actual substance exchange between the blood and neurons/glia occurs, by two-photon microscopy. Across multiple cortical areas, average capillary CBF is largely increased during rapid eye movement (REM) sleep, whereas it does not differ between periods of active wakefulness and non-REM sleep. Capillary RBC flow during REM sleep is further elevated following REM sleep deprivation, suggesting that capillary CBF reflects REM sleep pressure. At the molecular level, signaling via adenosine A2a receptors is crucial; in A2a-KO mice, capillary CBF upsurge during REM sleep is dampened, and effects of REM sleep pressure are abolished. These results provide evidence regarding the dynamics of capillary CBF across sleep/wake states and insights to the underlying mechanisms.
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Affiliation(s)
- Chia-Jung Tsai
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; Japan Society for the Promotion of Science (JSPS) International Research Fellow, Tokyo 102-0083, Japan
| | - Takeshi Nagata
- PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Chih-Yao Liu
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Takaya Suganuma
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Takeshi Kanda
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Takehiro Miyazaki
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Kai Liu
- Center for Mathematical Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tsuyoshi Saitoh
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Hiroshi Nagase
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Kaspar E Vogt
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Life Science Center for Survival Dynamics (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan; R&D Center for Frontiers of Mirai in Policy and Technology (F-MIRAI), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Yu Hayashi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 603-8363, Japan.
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36
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Leacy JK. Lessons from on high: arterial CO 2 , not pH, is the key mediator of cerebrovascular function. J Physiol 2021; 599:4247-4248. [PMID: 34311500 DOI: 10.1113/jp281999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jack K Leacy
- Department of Physiology, College of Medicine and Health, School of Medicine, University College Cork, Cork, Ireland
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37
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Stefanik E, Drewnowska O, Lisowska B, Turek B. Causes, Effects and Methods of Monitoring Gas Exchange Disturbances during Equine General Anaesthesia. Animals (Basel) 2021; 11:2049. [PMID: 34359177 PMCID: PMC8300395 DOI: 10.3390/ani11072049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/30/2021] [Accepted: 07/06/2021] [Indexed: 02/06/2023] Open
Abstract
Horses, due to their unique anatomy and physiology, are particularly prone to intraoperative cardiopulmonary disorders. In dorsally recumbent horses, chest wall movement is restricted and the lungs are compressed by the abdominal organs, leading to the collapse of the alveoli. This results in hypoventilation, leading to hypercapnia and respiratory acidosis as well as impaired tissue oxygen supply (hypoxia). The most common mechanisms disturbing gas exchange are hypoventilation, atelectasis, ventilation-perfusion (V/Q) mismatch and shunt. Gas exchange disturbances are considered to be an important factor contributing to the high anaesthetic mortality rate and numerous post-anaesthetic side effects. Current monitoring methods, such as a pulse oximetry, capnography, arterial blood gas measurements and spirometry, may not be sufficient by themselves, and only in combination with each other can they provide extensive information about the condition of the patient. A new, promising, complementary method is near-infrared spectroscopy (NIRS). The purpose of this article is to review the negative effect of general anaesthesia on the gas exchange in horses and describe the post-operative complications resulting from it. Understanding the changes that occur during general anaesthesia and the factors that affect them, as well as improving gas monitoring techniques, can improve the post-aesthetic survival rate and minimize post-operative complications.
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Affiliation(s)
- Elżbieta Stefanik
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
| | - Olga Drewnowska
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
| | - Barbara Lisowska
- National Geriatrics, Rheumatology and Rehabilitation Institute, Spartańska 1, 02-637 Warsaw, Poland;
| | - Bernard Turek
- Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
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38
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Stetter C, Weidner F, Lilla N, Weiland J, Kunze E, Ernestus RI, Muellenbach RM, Westermaier T. Therapeutic hypercapnia for prevention of secondary ischemia after severe subarachnoid hemorrhage: physiological responses to continuous hypercapnia. Sci Rep 2021; 11:11715. [PMID: 34083595 PMCID: PMC8175721 DOI: 10.1038/s41598-021-91007-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Temporary hypercapnia has been shown to increase cerebral blood flow (CBF) and might be used as a therapeutical tool in patients with severe subarachnoid hemorrhage (SAH). It was the aim of this study was to investigate the optimum duration of hypercapnia. This point is assumed to be the time at which buffer systems become active, cause an adaptation to changes of the arterial partial pressure of carbon dioxide (PaCO2) and annihilate a possible therapeutic effect. In this prospective interventional study in a neurosurgical ICU the arterial partial pressure of carbon dioxide (PaCO2) was increased to a target range of 55 mmHg for 120 min by modification of the respiratory minute volume (RMV) one time a day between day 4 and 14 in 12 mechanically ventilated poor-grade SAH-patients. Arterial blood gases were measured every 15 min. CBF and brain tissue oxygen saturation (StiO2) were the primary and secondary end points. Intracranial pressure (ICP) was controlled by an external ventricular drainage. Under continuous hypercapnia (PaCO2 of 53.17 ± 5.07), CBF was significantly elevated between 15 and 120 min after the start of hypercapnia. During the course of the trial intervention, cardiac output also increased significantly. To assess the direct effect of hypercapnia on brain perfusion, the increase of CBF was corrected by the parallel increase of cardiac output. The maximum direct CBF enhancing effect of hypercapnia of 32% was noted at 45 min after the start of hypercapnia. Thereafter, the CBF enhancing slowly declined. No relevant adverse effects were observed. CBF and StiO2 reproducibly increased by controlled hypercapnia in all patients. After 45 min, the curve of CBF enhancement showed an inflection point when corrected by cardiac output. It is concluded that 45 min might be the optimum duration for a therapeutic use and may provide an optimal balance between the benefits of hypercapnia and risks of a negative rebound effect after return to normal ventilation parameters. Trial registration: The study was approved by the institutional ethics committee (AZ 230/14) and registered at ClinicalTrials.gov (Trial-ID: NCT01799525). Registered 01/01/2015.
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Affiliation(s)
- Christian Stetter
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany.
| | - Franziska Weidner
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany.,Department of Neuroradiology, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany
| | - Nadine Lilla
- Department of Neurosurgery, University Hospital Magdeburg, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Judith Weiland
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany
| | - Ekkehard Kunze
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany
| | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany
| | - Ralf Michael Muellenbach
- Department of Anesthesia and Critical Care, University Hospital Wuerzburg, Oberduerrbacherstrasse 6, 97080, Wuerzburg, Germany.,Department of Anesthesiology, Klinikum Kassel, Moenchebergstrasse 41-43, 34125, Kassel, Germany
| | - Thomas Westermaier
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Strasse 11, 97080, Wuerzburg, Germany
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39
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Carr JMJR, Caldwell HG, Ainslie PN. Cerebral blood flow, cerebrovascular reactivity and their influence on ventilatory sensitivity. Exp Physiol 2021; 106:1425-1448. [PMID: 33932955 DOI: 10.1113/ep089446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 04/26/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? Cerebrovascular reactivity to CO2 , which is a principal factor in determining ventilatory responses to CO2 through the role reactivity plays in determining cerebral extra- and intracellular pH. What advances does it highlight? Recent animal evidence suggests central chemoreceptor vasculature may demonstrate regionally heterogeneous cerebrovascular reactivity to CO2 , potentially as a protective mechanism against excessive CO2 washout from the central chemoreceptors, thereby allowing ventilation to reflect the systemic acid-base balance needs (respiratory changes in P aC O 2 ) rather than solely the cerebral needs. Ventilation per se does not influence cerebrovascular reactivity independent of changes in P aC O 2 . ABSTRACT Alveolar ventilation and cerebral blood flow are both predominantly regulated by arterial blood gases, especially arterial P C O 2 , and so are intricately entwined. In this review, the fundamental mechanisms underlying cerebrovascular reactivity and central chemoreceptor control of breathing are covered. We discuss the interaction of cerebral blood flow and its reactivity with the control of ventilation and ventilatory responsiveness to changes in P C O 2 , as well as the lack of influence of ventilation itself on cerebrovascular reactivity. We briefly summarize the effects of arterial hypoxaemia on the relationship between ventilatory and cerebrovascular response to both P C O 2 and P O 2 . We then highlight key methodological considerations regarding the interaction of reactivity and ventilatory sensitivity, including the following: regional heterogeneity of cerebrovascular reactivity; a pharmacological approach for the reduction of cerebral blood flow; reactivity assessment techniques; the influence of mean arterial blood pressure; and sex-related differences. Finally, we discuss ventilatory and cerebrovascular control in the context of high altitude and congestive heart failure. Future research directions and pertinent questions of interest are highlighted throughout.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, British Columbia, Canada
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40
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YILMAZ DA, YILDIRIM MS, YILDIZ M, OKYAR G. CENTRAL NERVOUS SYSTEM RESPONSE TO CHRONIC KIDNEY DISEASE. KAHRAMANMARAŞ SÜTÇÜ İMAM ÜNIVERSITESI TIP FAKÜLTESI DERGISI 2021. [DOI: 10.17517/ksutfd.917658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Due to the aging of the human population, the prevalence of chronic diseases such as chronic kidney disease (CKD) is increasing every year. Chronic kidney disease is a general term that refers to heterogeneous disorders that affect kidney structure and function. Decrease in glomerular filtration can be defined as chronic and progressive deterioration in fluid-solute balance, metabolic and endocrine functions of the kidney. CKD often affects the elderly. With the advancement of age, some structural and functional changes occur in the kidneys. Therefore, the number of patients suffering from mild and moderate CKD is expected to increase in the future.CKD leads to the deep metabolic and hemodynamic changes that damage other organs, such as the heart and brain. CNS abnormalities and cognitive deficits progress with the severity of CBS and occurs mostly among hemodialysis patients. It also has great socio-economic effects on individuals. Since symptoms of CKD are not often found in patients, early recognition of risk factors is the main point. For this reason, it is necessary to identify possible protective and preventive treatments to be applied in at-risk groups and to examine these mechanisms for the treatment of the disease. This review provides available information on the relevant mechanisms.
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Darby JRT, Berry MJ, Quinn M, Holman SL, Bradshaw EL, Jesse SM, Haller C, Seed M, Morrison JL. Haemodynamics and cerebral oxygenation of neonatal piglets in the immediate ex utero period supported by mechanical ventilation or ex utero oxygenator. J Physiol 2021; 599:2751-2761. [PMID: 33745149 DOI: 10.1113/jp280803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 03/15/2021] [Indexed: 12/29/2022] Open
Abstract
KEY POINTS The margin of human viability has extended to the extremes of gestational age (<24 weeks) when the lungs are immature and ventilator-induced lung injury is common. Artificial placenta technology aims to extend gestation ex utero in order to allow the lungs additional time to develop prior to entering an air-breathing environment. We compared the haemodynamics and cerebral oxygenation of piglets in the immediate period post-oxygenator (OXY) transition against both paired in utero measures and uniquely against piglets transitioned onto mechanical ventilation (VENT). Post-transition, OXY piglets became hypotensive with reduced carotid blood flow in comparison with both paired in utero measures and VENT piglets. The addition of a pump to the oxygenator circuit may be required to ensure haemodynamic stability in the immediate post-transition period. ABSTRACT Gestational age at birth is a major predictor of wellbeing; the lower the gestational age, the greater the risk of mortality and morbidity. At the margins of human viability (<24 weeks gestation) immature lungs combined with the need for early ventilatory support means lung injury and respiratory morbidity is common. The abrupt haemodynamic changes consequent on birth may also contribute to preterm-associated brain injury, including intraventricular haemorrhage. Artificial placenta technology aims to support oxygenation, haemodynamic stability and ongoing fetal development ex utero until mature enough to safely transition to a true ex utero environment. We aimed to characterize the impact of birth transition onto either an oxygenator circuit or positive pressure ventilation on haemodynamic and cerebral oxygenation of the neonatal piglet. At 112 days gestation (term = 115 days), fetal pigs underwent instrumentation surgery and transitioned onto either an oxygenator (OXY, n = 5) or ventilatory support (VENT, n = 8). Blood pressure (BP), carotid blood flow and cerebral oxygenation in VENT piglets rose from in utero levels to be significantly higher than OXY piglets post-transition. OXY piglet BP, carotid blood flow and carotid oxygen delivery (DO2 ) decreased from in utero levels post-transition; however, cerebral regional oxygen saturation (rSO2 ) was maintained at fetal-like levels. OXY piglets became hypoxaemic and retained CO2 . Whether OXY piglets are able to maintain cerebral rSO2 under these conditions for a prolonged period is yet to be determined. Improvements to OXY piglet oxygenation may lie in maintaining piglet BP at in utero levels and enhancing oxygenator circuit flow.
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Affiliation(s)
- Jack R T Darby
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Mary J Berry
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand.,Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | - Megan Quinn
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Stacey L Holman
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Emma L Bradshaw
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Sarah M Jesse
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Christoph Haller
- Univeristy of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mike Seed
- Univeristy of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Janna L Morrison
- Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Stevens D, Jackson B, Carberry J, McLoughlin J, Barr C, Mukherjee S, Oh A, McEvoy RD, Crotty M, Vakulin A. The Impact of Obstructive Sleep Apnea on Balance, Gait, and Falls Risk: A Narrative Review of the Literature. J Gerontol A Biol Sci Med Sci 2021; 75:2450-2460. [PMID: 32039438 DOI: 10.1093/gerona/glaa014] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Indexed: 12/24/2022] Open
Abstract
Falls-related hospitalization and injury rates are steadily increasing globally due to a growth in the aging population, and the associated health problems that increase risk of falls. One such associated health problem is sleep disturbances and disorders. Recent cohort studies have shown that subjectively reported poor quality sleep is associated with an increased risk of falls. Obstructive sleep apnea (OSA) is a common sleep disorder characterized by the repetitive reductions, or cessation, of airflow. Some studies have shown that OSA impairs posture/balance and gait with nocturnal hypoxemia the likely main cause. Emerging evidence suggests that treating OSA by continuous positive airway pressure (CPAP) can improve gait, but no studies to date have examined the effect of CPAP on posture/balance. The overall control of balance relies on a complex interaction between several physiological functions including vestibular, muscle, visual, and cognitive functions. We postulate that OSA impacts balance by affecting these different systems to various degrees, with the nocturnal hypoxic burden likely playing an important role. Importantly, these impairments in balance/posture and possible falls risk may be alleviated by OSA treatment. Larger mechanistic studies are needed to properly elucidate how OSA affects falls risk and future large-scale randomized control trials are needed to determine the effectiveness of OSA treatment in reducing the risk of falls.
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Affiliation(s)
- David Stevens
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia
| | - Brianna Jackson
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia
| | - Jayne Carberry
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia
| | - James McLoughlin
- College of Nursing and Health Science, Flinders University, South Australia, Australia
| | - Chris Barr
- College of Nursing and Health Science, Flinders University, South Australia, Australia
| | - Sutapa Mukherjee
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia.,Sleep Health Service, Sleep and Respiratory Services, Flinders Medical Centre, Southern Adelaide Local Health Network, South Australia, Australia
| | - Aaron Oh
- Sleep Health Service, Sleep and Respiratory Services, Flinders Medical Centre, Southern Adelaide Local Health Network, South Australia, Australia
| | - R Doug McEvoy
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia
| | - Maria Crotty
- Department of Rehabilitation, Aged, and Extended Aged Care, College of Medicine and Public Health, Flinders University, South Australia, Australia.,4th Generation Rehabilitation Clinic, Flinders Medical Centre, Southern Adelaide Local Health Network, South Australia, Australia
| | - Andrew Vakulin
- Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, South Australia, Australia.,Neurosleep CRE, Woolcock Institute of Medical Research, New South Wales, Australia
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43
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Deverdun J, Coget A, Ayrignac X, Carra-Dalliere C, Krainik A, Metzger A, Labauge P, Menjot de Champfleur N, Le Bars E. Cerebral Vasoreactivity as an Indirect MRI Marker of White Matter Tracts Alterations in Multiple Sclerosis. Brain Topogr 2021; 34:245-255. [PMID: 33484378 DOI: 10.1007/s10548-021-00819-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/06/2021] [Indexed: 02/02/2023]
Abstract
Patients with multiple sclerosis (MS) show a diffuse cerebral perfusion decrease, presumably related to multiple metabolism and vascular alterations. It is assumed that white matter fiber alterations cause a localized cerebral vasoreactivity (CVR) disruption through astrocytes metabolism alteration, leading to hypoperfusion. We proposed to (1) evaluate the CVR disruptions in MS, (2) in relation to white matter lesions and (3) compare CVR disruptions maps with standard imaging biomarkers. Thirty-five MS patients (10 progressive, 25 relapsing-remitting) and 22 controls underwent MRI with hypercapnic challenge, DTI imaging and neuropsychological assessment. Areas with disrupted CVR were assessed using a general linear model. Resulting maps were associated with clinical scores, compared between groups, and related to DTI metrics and white matter lesions. MS patients showed stronger disrupted CVR within supratentorial white matter, linking the left anterior insula to both the precentral gyrus and the right middle and superior frontal gyrus through the corpus callosum (P < 0.05, FWE corrected). Patient's verbal intellectual quotient was negatively associated with a pathway linking both hippocampi to the ispilateral prefrontal cortex (P < 0.05, FWE corrected). Disrupted CVR maps unrelated to DTI metrics and white matter lesions. We have demonstrated for the first time that white matter alterations can be indirectly identified through surrounding vessel alterations, and are related to clinical signs of MS. This offers a new, likely independent marker to monitor MS and supports a mediator role of the astrocytes in the fibers/vessels relationship.
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Affiliation(s)
- Jeremy Deverdun
- Department of Neuroradiology, University Hospital Center, I2FH, Institut d'Imagerie Fonctionnelle Humaine, Gui de Chauliac Hospital, 80 Avenue Augustin Fliche, 34295 Cedex 5, Montpellier, France.
| | - Arthur Coget
- Department of Neuroradiology, University Hospital Center, I2FH, Institut d'Imagerie Fonctionnelle Humaine, Gui de Chauliac Hospital, 80 Avenue Augustin Fliche, 34295 Cedex 5, Montpellier, France
- Department of Neuroradiology, Montpellier University Hospital, Gui de Chauliac Hospital, Montpellier, France
- Laboratoire Charles Coulomb, University of Montpellier, 34095, Montpellier, France
| | - Xavier Ayrignac
- Department of Neurology, MS Center and National Reference Center of Adult Leukodystrophies, Montpellier University Hospital, 34 295 Cedex 5, Montpellier, France
| | - Clarisse Carra-Dalliere
- Department of Neurology, MS Center and National Reference Center of Adult Leukodystrophies, Montpellier University Hospital, 34 295 Cedex 5, Montpellier, France
| | - Alexandre Krainik
- Department of Neuroradiology and MRI, Grenoble Institute of Neurosciences, INSERM U836, UMS IRMaGe, Grenoble University Hospital, University Grenoble Alps, Grenoble, France
- Department of Pediatrics, Bordeaux University Hospital, Bordeaux, France
| | - Aude Metzger
- Department of neuro -ophthalmology and neuro cognition, Pierre Wertheimer University Hospital, 69500, Bron, France
| | - Pierre Labauge
- Department of Neurology, MS Center and National Reference Center of Adult Leukodystrophies, Montpellier University Hospital, 34 295 Cedex 5, Montpellier, France
| | - Nicolas Menjot de Champfleur
- Department of Neuroradiology, University Hospital Center, I2FH, Institut d'Imagerie Fonctionnelle Humaine, Gui de Chauliac Hospital, 80 Avenue Augustin Fliche, 34295 Cedex 5, Montpellier, France
- Department of Neuroradiology, Montpellier University Hospital, Gui de Chauliac Hospital, Montpellier, France
- Team "Plasticity of Central Nervous System, Stem Cells and Glial Tumors", INSERM U1051, Institute of Neurosciences of Montpellier, Montpellier, France
- Laboratoire Charles Coulomb, University of Montpellier, 34095, Montpellier, France
| | - Emmanuelle Le Bars
- Department of Neuroradiology, University Hospital Center, I2FH, Institut d'Imagerie Fonctionnelle Humaine, Gui de Chauliac Hospital, 80 Avenue Augustin Fliche, 34295 Cedex 5, Montpellier, France
- Department of Neuroradiology, Montpellier University Hospital, Gui de Chauliac Hospital, Montpellier, France
- Laboratoire Charles Coulomb, University of Montpellier, 34095, Montpellier, France
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Caldwell HG, Howe CA, Chalifoux CJ, Hoiland RL, Carr JMJR, Brown CV, Patrician A, Tremblay JC, Panerai RB, Robinson TG, Minhas JS, Ainslie PN. Arterial carbon dioxide and bicarbonate rather than pH regulate cerebral blood flow in the setting of acute experimental metabolic alkalosis. J Physiol 2021; 599:1439-1457. [DOI: 10.1113/jp280682] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Affiliation(s)
- Hannah G. Caldwell
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Connor A. Howe
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Carter J. Chalifoux
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Ryan L. Hoiland
- Department of Anesthesiology Pharmacology and Therapeutics Vancouver General Hospital University of British Columbia Vancouver BC Canada
- Department of Cellular and Physiological Sciences University of British Columbia Vancouver BC Canada
| | - Jay M. J. R. Carr
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Courtney V. Brown
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Alexander Patrician
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Joshua C. Tremblay
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
| | - Ronney B. Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group Leicester Biomedical Research Centre University of Leicester Leicester UK
| | - Thompson G. Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group Leicester Biomedical Research Centre University of Leicester Leicester UK
| | - Jatinder S. Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group Leicester Biomedical Research Centre University of Leicester Leicester UK
| | - Philip N. Ainslie
- Centre for Heart, Lung and Vascular Health School of Health and Exercise Sciences University of British Columbia Okanagan Kelowna BC Canada
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45
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Ghoshal S, Freedman BI. Renal Replacement Therapy and Dialysis-associated Neurovascular Injury (DANI) in the Neuro ICU: a Review of Pathophysiology and Preventative Options. Curr Treat Options Neurol 2021. [DOI: 10.1007/s11940-020-00661-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Leon RL, Ortigoza EB, Ali N, Angelis D, Wolovits JS, Chalak LF. Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations. Front Pediatr 2021; 9:748345. [PMID: 35087771 PMCID: PMC8787287 DOI: 10.3389/fped.2021.748345] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/15/2021] [Indexed: 12/18/2022] Open
Abstract
Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.
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Affiliation(s)
- Rachel L Leon
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Eric B Ortigoza
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Noorjahan Ali
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Dimitrios Angelis
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Joshua S Wolovits
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Lina F Chalak
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
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47
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Volatile Anesthetics Activate a Leak Sodium Conductance in Retrotrapezoid Nucleus Neurons to Maintain Breathing during Anesthesia in Mice. Anesthesiology 2020; 133:824-838. [PMID: 32773689 DOI: 10.1097/aln.0000000000003493] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Volatile anesthetics moderately depress respiratory function at clinically relevant concentrations. Phox2b-expressing chemosensitive neurons in the retrotrapezoid nucleus, a respiratory control center, are activated by isoflurane, but the underlying mechanisms remain unclear. The hypothesis of this study was that the sodium leak channel contributes to the volatile anesthetics-induced modulation of retrotrapezoid nucleus neurons and to respiratory output. METHODS The contribution of sodium leak channels to isoflurane-, sevoflurane-, and propofol-evoked activity of Phox2b-expressing retrotrapezoid nucleus neurons and respiratory output were evaluated in wild-type and genetically modified mice lacking sodium leak channels (both sexes). Patch-clamp recordings were performed in acute brain slices. Whole-body plethysmography was used to measure the respiratory activity. RESULTS Isoflurane at 0.42 to 0.50 mM (~1.5 minimum alveolar concentration) increased the sodium leak channel-mediated holding currents and conductance from -75.0 ± 12.9 to -130.1 ± 34.9 pA (mean ± SD, P = 0.002, n = 6) and 1.8 ± 0.5 to 3.6 ± 1.0 nS (P = 0.001, n = 6), respectively. At these concentrations, isoflurane increased activity of Phox2b-expressing retrotrapezoid nucleus neurons from 1.1 ± 0.2 to 2.8 ± 0.2 Hz (P < 0.001, n = 5), which was eliminated by bath application of gadolinium or genetic silencing of sodium leak channel. Genetic silencing of sodium leak channel in the retrotrapezoid nucleus resulted in a diminished ventilatory response to carbon dioxide in mice under control conditions and during isoflurane anesthesia. Sevoflurane produced an effect comparable to that of isoflurane, whereas propofol did not activate sodium leak channel-mediated holding conductance. CONCLUSIONS Isoflurane and sevoflurane increase neuronal excitability of chemosensitive retrotrapezoid nucleus neurons partly by enhancing sodium leak channel conductance. Sodium leak channel expression in the retrotrapezoid nucleus is required for the ventilatory response to carbon dioxide during anesthesia by isoflurane and sevoflurane, thus identifying sodium leak channel as a requisite determinant of respiratory output during anesthesia of volatile anesthetics. EDITOR’S PERSPECTIVE
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48
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Buxton RB. The thermodynamics of thinking: connections between neural activity, energy metabolism and blood flow. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190624. [PMID: 33190604 DOI: 10.1098/rstb.2019.0624] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Several current functional neuroimaging methods are sensitive to cerebral metabolism and cerebral blood flow (CBF) rather than the underlying neural activity itself. Empirically, the connections between metabolism, flow and neural activity are complex and somewhat counterintuitive: CBF and glycolysis increase more than seems to be needed to provide oxygen and pyruvate for oxidative metabolism, and the oxygen extraction fraction is relatively low in the brain and decreases when oxygen metabolism increases. This work lays a foundation for the idea that this unexpected pattern of physiological changes is consistent with basic thermodynamic considerations related to metabolism. In the context of this thermodynamic framework, the apparent mismatches in metabolic rates and CBF are related to preserving the entropy change of oxidative metabolism, specifically the O2/CO2 ratio in the mitochondria. However, the mechanism supporting this CBF response is likely not owing to feedback from a hypothetical O2 sensor in tissue, but rather is consistent with feed-forward control by signals from both excitatory and inhibitory neural activity. Quantitative predictions of the thermodynamic framework, based on models of O2 and CO2 transport and possible neural drivers of CBF control, are in good agreement with a wide range of experimental data, including responses to neural activation, hypercapnia, hypoxia and high-altitude acclimatization. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Richard B Buxton
- Department of Radiology, University of California San Diego, 9500 Gilman Drive, MC 0677, La Jolla, CA 92093-0677, USA
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49
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Abstract
PURPOSE To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion.
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Affiliation(s)
- Noushin Yazdani
- College of Public Health, University of South Florida , Tampa, FL, USA
| | - Mark S Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Biomedical Research, James A. Haley VA Medical Center , Tampa, FL, USA
| | - Saeid Taheri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Byrd Neuroscience Institute, University of South Florida , Tampa, FL, USA
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50
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van der Kleij LA, De Vis JB, de Bresser J, Hendrikse J, Siero JCW. Arterial CO 2 pressure changes during hypercapnia are associated with changes in brain parenchymal volume. Eur Radiol Exp 2020; 4:17. [PMID: 32147754 PMCID: PMC7061094 DOI: 10.1186/s41747-020-0144-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 01/23/2020] [Indexed: 11/10/2022] Open
Abstract
The Monro-Kellie hypothesis (MKH) states that volume changes in any intracranial component (blood, brain tissue, cerebrospinal fluid) should be counterbalanced by a co-occurring opposite change to maintain intracranial pressure within the fixed volume of the cranium. In this feasibility study, we investigate the MKH application to structural magnetic resonance imaging (MRI) in observing compensating intracranial volume changes during hypercapnia, which causes an increase in cerebral blood volume. Seven healthy subjects aged from 24 to 64 years (median 32), 4 males and 3 females, underwent a 3-T three-dimensional T1-weighted MRI under normocapnia and under hypercapnia. Intracranial tissue volumes were computed. According to the MKH, the significant increase in measured brain parenchymal volume (median 6.0 mL; interquartile range 4.5, 8.5; p = 0.016) during hypercapnia co-occurred with a decrease in intracranial cerebrospinal fluid (median -10.0 mL; interquartile range -13.5, -6.5; p = 0.034). These results convey several implications: (i) blood volume changes either caused by disorders, anaesthesia, or medication can affect outcome of brain volumetric studies; (ii) besides probing tissue displacement, this approach may assess the brain cerebrovascular reactivity. Future studies should explore the use of alternative sequences, such as three-dimensional T2-weighted imaging, for improved quantification of hypercapnia-induced volume changes.
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Affiliation(s)
- Lisa A van der Kleij
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
| | - Jill B De Vis
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jeroen de Bresser
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Jeroen C W Siero
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.,Spinoza Center for Neuroimaging, Amsterdam, The Netherlands
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