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DiNuzzo M, Dienel GA, Behar KL, Petroff OA, Benveniste H, Hyder F, Giove F, Michaeli S, Mangia S, Herculano-Houzel S, Rothman DL. Neurovascular coupling is optimized to compensate for the increase in proton production from nonoxidative glycolysis and glycogenolysis during brain activation and maintain homeostasis of pH, pCO 2, and pO 2. J Neurochem 2024; 168:632-662. [PMID: 37150946 PMCID: PMC10628336 DOI: 10.1111/jnc.15839] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 04/22/2023] [Accepted: 05/02/2023] [Indexed: 05/09/2023]
Abstract
During transient brain activation cerebral blood flow (CBF) increases substantially more than cerebral metabolic rate of oxygen consumption (CMRO2) resulting in blood hyperoxygenation, the basis of BOLD-fMRI contrast. Explanations for the high CBF versus CMRO2 slope, termed neurovascular coupling (NVC) constant, focused on maintenance of tissue oxygenation to support mitochondrial ATP production. However, paradoxically the brain has a 3-fold lower oxygen extraction fraction (OEF) than other organs with high energy requirements, like heart and muscle during exercise. Here, we hypothesize that the NVC constant and the capillary oxygen mass transfer coefficient (which in combination determine OEF) are co-regulated during activation to maintain simultaneous homeostasis of pH and partial pressure of CO2 and O2 (pCO2 and pO2). To test our hypothesis, we developed an arteriovenous flux balance model for calculating blood and brain pH, pCO2, and pO2 as a function of baseline OEF (OEF0), CBF, CMRO2, and proton production by nonoxidative metabolism coupled to ATP hydrolysis. Our model was validated against published brain arteriovenous difference studies and then used to calculate pH, pCO2, and pO2 in activated human cortex from published calibrated fMRI and PET measurements. In agreement with our hypothesis, calculated pH, pCO2, and pO2 remained close to constant independently of CMRO2 in correspondence to experimental measurements of NVC and OEF0. We also found that the optimum values of the NVC constant and OEF0 that ensure simultaneous homeostasis of pH, pCO2, and pO2 were remarkably similar to their experimental values. Thus, the high NVC constant is overall determined by proton removal by CBF due to increases in nonoxidative glycolysis and glycogenolysis. These findings resolve the paradox of the brain's high CBF yet low OEF during activation, and may contribute to explaining the vulnerability of brain function to reductions in blood flow and capillary density with aging and neurovascular disease.
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Affiliation(s)
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205 USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, NM, 87131 USA
| | - Kevin L Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Ognen A Petroff
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale University, New Haven, CT, 06520 USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
| | - Fahmeed Hyder
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
| | - Federico Giove
- Centro Ricerche Enrico Fermi, Rome, RM, 00184 Italy
- Fondazione Santa Lucia IRCCS, Rome, RM, 00179 Italy
| | - Shalom Michaeli
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Silvia Mangia
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN
| | - Douglas L Rothman
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
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Ortiz-Prado E, Izquierdo-Condoy JS, Fernández-Naranjo R, Vásconez-González J, Cano L, González AC, Morales-Lapo E, Guerrero-Castillo GS, Duque E, Rosero MGD, Egas D, Viscor G. Epidemiological characterization of ischemic heart disease at different altitudes: A nationwide population-based analysis from 2011 to 2021 in Ecuador. PLoS One 2023; 18:e0295586. [PMID: 38157383 PMCID: PMC10756509 DOI: 10.1371/journal.pone.0295586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/22/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND Cardiovascular diseases, including ischemic heart disease, are the leading cause of premature death and disability worldwide. While traditional risk factors such as smoking, obesity, and diabetes have been thoroughly investigated, non-traditional risk factors like high-altitude exposure remain underexplored. This study aims to examine the incidence and mortality rates of ischemic heart disease over the past decade in Ecuador, a country with a diverse altitude profile spanning from 0 to 4,300 meters. METHODS We conducted a geographic distribution analysis of ischemic heart disease in Ecuador, utilizing hospital discharge and mortality data from the National Institute of Census and Statistics for the years 2011-2021. Altitude exposure was categorized according to two distinct classifications: the traditional division into low (< 2,500 m) and high (> 2,500 m) altitudes, as well as the classification proposed by the International Society of Mountain Medicine, which delineates low (< 1,500 m), moderate (1,500-2,500 m), high (2,500-3,500 m), and very high (3,500-5,800 m) altitudes. FINDINGS From 2011-2021, we analyzed 49,765 IHD-related hospital admissions and 62,620 deaths. Men had an age-adjusted incidence rate of 55.08/100,000 and a mortality rate of 47.2/100,000, compared to 20.77/100,000 and 34.8/100,000 in women. Incidence and mortality surged in 2020 by 83% in men and 75% in women. Altitudinal stratification revealed higher IHD rates at lower altitudes (<2500 m), averaging 61.65 and 121.8 per 100,000 for incidence and mortality, which declined to 25.9 and 38.5 at elevations >2500 m. Men had more pronounced rates across altitudes, exhibiting 138.7% and 150.0% higher incidence at low and high altitudes respectively, and mortality rates increased by 48.3% at low altitudes and 23.2% at high altitudes relative to women. CONCLUSION Ecuador bears a significant burden of ischemic heart disease (IHD), with men being more affected than women in terms of incidence. However, women have a higher percentage of mortality post-hospital admission. Regarding elevation, our analysis, using two different altitude cutoff points, reveals higher mortality rates in low-altitude regions compared to high-altitude areas, suggesting a potential protective effect of high elevation on IHD risk. Nevertheless, a definitive dose-response relationship between high altitude and reduced IHD risk could not be conclusively established.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | | | - Raúl Fernández-Naranjo
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | | | - Leonardo Cano
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | - Ana Carolina González
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
- Pós Graduação de Clinica Medica, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brasil
| | - Estefanía Morales-Lapo
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | | | - Erick Duque
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | | | - Diego Egas
- Departamento de Cardiología, Hospital Metropolitano, Quito, Ecuador
| | - Ginés Viscor
- Departament de Biología Cel·lular, Fisiologia i Immunologia, Universitat de Barcelona, Barcelona, Spain
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Yu L, Peng Y, Jiang L, Qiu L. Sequential Diagnosis and Treatment for Colon Cancer via Derived Iridium and Indocyanine Green Hybrid Nanomicelles. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37437265 DOI: 10.1021/acsami.3c07742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Indocyanine green (ICG) has been widely explored for the theranostics of tumors. However, ICG mainly accumulates in the liver, spleen, or kidney in addition to in tumors, causing inaccurate diagnoses and impaired therapeutic effects under NIR irradiation. Herein, a hybrid nanomicelle was constructed by integrating hypoxia-sensitive iridium(III) and ICG for precise tumor localization and photothermal therapy in sequence. In this nanomicelle, the amphiphilic iridium(III) complex (BTPH)2Ir(SA-PEG) was synthesized through the coordination substitution of hydrophobic (BTPH)2IrCl2 and hydrophilic PEGlyated succinylacetone (SA-PEG). Meanwhile, PEGlyated ICG (ICG-PEG) as a derivative of the photosensitizer ICG was also synthesized. (BTPH)2Ir(SA-PEG) and ICG-PEG were coassembled by dialysis to form the hybrid nanomicelle M-Ir-ICG. Hypoxia-sensitive fluorescence, ROS generation, and the photothermal effect of M-Ir-ICG were investigated in vitro and in vivo. The experimental results indicated that M-Ir-ICG nanomicelles could locate at the tumor site first and then perform photothermal therapy with 83.90% TIR, demonstrating great potential for clinical applications.
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Affiliation(s)
- Liang Yu
- Ministry of Educational (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yan Peng
- Ministry of Educational (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Linping Jiang
- Ministry of Educational (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liyan Qiu
- Ministry of Educational (MOE) Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
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Shu J, Fei W, Zhang J, Li F, Hao Y, Ding Z, Tseyang, Drolma, Ji S, Zhao W, Hu Y, Sun W, Huang Y, Zhao Y, Zhang W. Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain. Front Neurol 2023; 14:1086476. [PMID: 36970535 PMCID: PMC10034167 DOI: 10.3389/fneur.2023.1086476] [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: 11/01/2022] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Background and purpose Cerebral small-vessel disease (CSVD) is prevalent worldwide and one of the major causes of stroke and dementia. For patients with CSVD at high altitude, a special environmental status, limited information is known about their clinical phenotype and specific neuroimaging change. We investigated the clinical and neuroimaging features of patients residing at high altitude by comparing with those in the plain, trying to explore the impact of high altitude environment on CSVD. Methods Two cohorts of CSVD patients from the Tibet Autonomous Region and Beijing were recruited retrospectively. In addition to the collection of clinical diagnoses, demographic information and traditional vascular risk factors, the presence, location, and severity of lacunes and white matter hyperintensities were assessed by manual counting and using age-related white matter changes (ARWMC) rating scale. Differences between the two groups and influence of long-term residing in the plateau were analyzed. Results A total of 169 patients in Tibet (high altitude) and 310 patients in Beijing (low altitude) were enrolled. Fewer patients in high altitude group were found with acute cerebrovascular events and concomitant traditional vascular risk factors. The median (quartiles) ARWMC score was 10 (4, 15) in high altitude group and 6 (3, 12) in low altitude group. Less lacunes were detected in high altitude group [0 (0, 4)] than in low altitude group [2 (0, 5)]. In both groups, most lesions located in the subcortical (especially frontal) and basal ganglia regions. Logistic regressions showed that age, hypertension, family history of stroke, and plateau resident were independently associated with severe white matter hyperintensities, while plateau resident was negatively correlated with lacunes. Conclusion Patients of CSVD residing at high altitude showed more severe WMH but less acute cerebrovascular events and lacunes in neuroimaging, comparing to patients residing at low altitude. Our findings suggest potential biphasic effect of high altitude on the occurrence and progression of CSVD.
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Affiliation(s)
- Junlong Shu
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Wen Fei
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Jing Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Fan Li
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yu Hao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Zhijie Ding
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Tseyang
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Drolma
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Shiyong Ji
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Weiwei Zhao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Yaxiong Hu
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Wei Sun
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Yuhua Zhao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
- Yuhua Zhao
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
- *Correspondence: Wei Zhang
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Ortiz-Prado E, Villafuerte FC, Brugniaux JV, Izquierdo-Condoy J, Viscor G. Editorial: Stroke and infarction at high-altitude. Front Physiol 2022; 13:1114747. [PMID: 36569767 PMCID: PMC9782429 DOI: 10.3389/fphys.2022.1114747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador,*Correspondence: Esteban Ortiz-Prado,
| | - Francisco C. Villafuerte
- Laboratorio de Fisiología Comparada-LID/Fisiología del Transporte de Oxígeno-IIA, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Juan Izquierdo-Condoy
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Ginés Viscor
- Dirección Nacional de Inteligencia de la Salud, Ministerio de Salud Púbica, Quito, Ecuador
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Ortiz-Prado E, Mendieta G, Simbaña-Rivera K, Gomez-Barreno L, Landazuri S, Vasconez E, Calvopiña M, Viscor G. Genotyped indigenous Kiwcha adults at high altitude are lighter and shorter than their low altitude counterparts. J Physiol Anthropol 2022; 41:8. [PMID: 35272696 PMCID: PMC8908589 DOI: 10.1186/s40101-022-00280-6] [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: 09/29/2021] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Background Anthropometric measures have been classically used to understand the impact of environmental factors on the living conditions of individuals and populations. Most reference studies on development and growth in which anthropometric measures were used were carried out in populations that are located at sea level, but there are few studies carried out in high altitude populations. Objective The objective of this study was to evaluate the anthropometric and body composition in autochthonous Kiwcha permanently living at low and high altitudes. Methodology A cross-sectional study of anthropometric and body composition between genetically matched lowland Kiwcha from Limoncocha (n = 117), 230 m in the Amazonian basin, and high-altitude Kiwcha from Oyacachi (n = 95), 3800 m in Andean highlands. Student’s t-test was used to analyze the differences between continuous variables, and the chi-square test was performed to check the association or independence of categorical variables. Fisher’s exact test or Spearman’s test was used when the variable had evident asymmetries with histograms prior to the selection of the test. Results This study shows that high altitude men are shorter than their counterparts who live at low altitude, with p = 0.019. About body muscle percentage, women at high altitudes have less body muscle percentage (− 24.8%). In comparison, men at high altitudes have significantly more muscle body mass percentage (+ 13.5%) than their lowland counterparts. Body fat percentage was lower among low altitude women (− 15.5%), and no differences were found among men. Conclusions This is the first study to be performed in two genotyped controlled matching populations located at different altitudes to our best knowledge. The anthropometric differences vary according to sex, demonstrating that high altitude populations are, in general, lighter and shorter than their low altitude controls. Men at high altitude have more muscled bodies compared to their lowland counterparts, but their body age was older than their actual age. Supplementary Information The online version contains supplementary material available at 10.1186/s40101-022-00280-6.
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Malik H, Wolff MD, Teskey GC, Mychasiuk R. Electrographic seizures and brain hyperoxia may be key etiological factors for post-concussive deficits. J Neurophysiol 2022; 128:727-737. [PMID: 35976074 PMCID: PMC9484996 DOI: 10.1152/jn.00533.2021] [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] [Indexed: 12/04/2022] Open
Abstract
Repetitive mild traumatic brain injuries (RmTBIs) are increasingly recognized to have long-term neurological sequelae in a significant proportion of patients. Individuals that have had RmTBIs exhibit a variety of sensory, cognitive, or behavioral consequences that can negatively impact quality of life. Brain tissue oxygen levels (PO2) are normally maintained through exquisite regulation of blood supply to stay within the normoxic zone (18–30 mmHg in the rat hippocampus). However, during neurological events in which brain tissue oxygen levels leave the normoxic zone, neuronal dysfunction and behavioral deficits have been observed, and are frequently related to poorer prognoses. The oxygenation response in the brain after RmTBIs/repeated concussions has been poorly characterized, with most preliminary research limited to the neocortex. Furthermore, the mechanisms by which RmTBIs impact changes to brain oxygenation and vice versa remain to be determined. In the current study, we demonstrate that upon receiving RmTBIs, rats exhibit posttraumatic, electrographic seizures in the hippocampus, without behavioral (clinical) seizures, that are accompanied by a long-lasting period of hyperoxygenation. These electrographic seizures and the ensuing hyperoxic episodes are associated with deficits in working memory and motor coordination that were reversible through attenuation of the posttraumatic and postictal (postseizure) hyperoxia, via administration of a vasoconstricting agent, the calcium channel agonist Bay K8644. We propose that the posttraumatic period characterized by brain oxygenation levels well above the normoxic zone, may be the basis for some of the common symptoms associated with RmTBIs. NEW & NOTEWORTHY We monitor oxygenation and electrographic activity in the hippocampus, immediately before and after mild traumatic brain injury. We demonstrate that as the number of injuries increases from 1 to 3, the proportion of rats that exhibit electrographic seizures and hyperoxia increases. Moreover, the presence of electrographic seizures and hyperoxia are associated with postinjury behavioral impairments, and if the hyperoxia is blocked with Bay K8644, the behavioral deficits are eliminated.
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Affiliation(s)
- Haris Malik
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Marshal D Wolff
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Canada
| | - Richelle Mychasiuk
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada.,Department of Psychology, University of Calgary, Calgary, Canada.,Department of Neuroscience, Monash University, Melbourne, Australia
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Harris SA, George AG, Barrett KT, Scantlebury MH, Teskey GC. Febrile seizures lead to prolonged epileptiform activity and hyperoxia that when blocked prevents learning deficits. Epilepsia 2022; 63:2650-2663. [DOI: 10.1111/epi.17371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/31/2022] [Accepted: 07/18/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Sydney A. Harris
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
- Alberta Children’s Hospital Research Institute University of Calgary Calgary AB Canada
| | - Antis G. George
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
| | - Karlene T. Barrett
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
- Alberta Children’s Hospital Research Institute University of Calgary Calgary AB Canada
- Departments of Pediatrics and Clinical Neurosciences University of Calgary Calgary AB Canada
| | - Morris H. Scantlebury
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
- Alberta Children’s Hospital Research Institute University of Calgary Calgary AB Canada
- Departments of Pediatrics and Clinical Neurosciences University of Calgary Calgary AB Canada
| | - G. Campbell Teskey
- Hotchkiss Brain Institute University of Calgary Calgary AB Canada
- Alberta Children’s Hospital Research Institute University of Calgary Calgary AB Canada
- Department of Cell Biology and Anatomy University of Calgary Calgary AB Canada
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López-Cortés A, Prathap L, Ortiz-Prado E, Kyriakidis NC, León Cáceres Á, Armendáriz-Castillo I, Vera-Guapi A, Yumiceba V, Simbaña-Rivera K, Echeverría-Garcés G, García-Cárdenas JM, Pérez-Villa A, Guevara-Ramírez P, Abad-Sojos A, Bautista J, Puig San Andrés L, Varela N, Guerrero S. The close interaction between hypoxia-related proteins and metastasis in pancarcinomas. Sci Rep 2022; 12:11100. [PMID: 35773405 PMCID: PMC9246854 DOI: 10.1038/s41598-022-15246-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/21/2022] [Indexed: 11/25/2022] Open
Abstract
Many primary-tumor subregions exhibit low levels of molecular oxygen and restricted access to nutrients due to poor vascularization in the tissue, phenomenon known as hypoxia. Hypoxic tumors are able to regulate the expression of certain genes and signaling molecules in the microenvironment that shift it towards a more aggressive phenotype. The transcriptional landscape of the tumor favors malignant transformation of neighboring cells and their migration to distant sites. Herein, we focused on identifying key proteins that participate in the signaling crossroads between hypoxic environment and metastasis progression that remain poorly defined. To shed light on these mechanisms, we performed an integrated multi-omics analysis encompassing genomic/transcriptomic alterations of hypoxia-related genes and Buffa hypoxia scores across 17 pancarcinomas taken from the PanCancer Atlas project from The Cancer Genome Atlas consortium, protein-protein interactome network, shortest paths from hypoxia-related proteins to metastatic and angiogenic phenotypes, and drugs involved in current clinical trials to treat the metastatic disease. As results, we identified 30 hypoxia-related proteins highly involved in metastasis and angiogenesis. This set of proteins, validated with the MSK-MET Project, could represent key targets for developing therapies. The upregulation of mRNA was the most prevalent alteration in all cancer types. The highest frequencies of genomic/transcriptomic alterations and hypoxia score belonged to tumor stage 4 and positive metastatic status in all pancarcinomas. The most significantly associated signaling pathways were HIF-1, PI3K-Akt, thyroid hormone, ErbB, FoxO, mTOR, insulin, MAPK, Ras, AMPK, and VEGF. The interactome network revealed high-confidence interactions among hypoxic and metastatic proteins. The analysis of shortest paths revealed several ways to spread metastasis and angiogenesis from hypoxic proteins. Lastly, we identified 23 drugs enrolled in clinical trials focused on metastatic disease treatment. Six of them were involved in advanced-stage clinical trials: aflibercept, bevacizumab, cetuximab, erlotinib, ipatasertib, and panitumumab.
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Affiliation(s)
- Andrés López-Cortés
- Programa de Investigación en Salud Global, Facultad de Ciencias de la Salud, Universidad Internacional SEK, 170302, Quito, Ecuador.
- Escuela de Medicina, Facultad de Ciencias de la Salud, Universidad de Las Américas, 170124, Quito, Ecuador.
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain.
| | - Lavanya Prathap
- Department of Anatomy, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, 600077, Chennai, India
| | - Esteban Ortiz-Prado
- One Health Research Group, Universidad de Las Américas, 170124, Quito, Ecuador
| | | | - Ángela León Cáceres
- Heidelberg Institute of Global Health, Faculty of Medicine, University of Heidelberg, 69117, Heidelberg, Germany
| | - Isaac Armendáriz-Castillo
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
- Instituto Nacional de Investigación en Salud Pública, 170136, Quito, Ecuador
- Facultad de Ingenierías y Ciencias Aplicadas, Universidad Internacional SEK, 170302, Quito, Ecuador
| | - Antonella Vera-Guapi
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07747, Jena, Germany
| | - Verónica Yumiceba
- Institut Für Humangenetik Lübeck, Universität Zu Lübeck, 23562, Lübeck, Germany
| | - Katherine Simbaña-Rivera
- One Health Research Group, Universidad de Las Américas, 170124, Quito, Ecuador
- Latin American Network for Cancer Research (LAN-CANCER), Lima, Peru
| | - Gabriela Echeverría-Garcés
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
| | - Jennyfer M García-Cárdenas
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
- Laboratorio de Ciencia de Datos Biomédicos, Escuela de Medicina, Facultad de Ciencias Médicas de la Salud y de la Vida, Universidad Internacional del Ecuador, 170113, Quito, Ecuador
| | - Andy Pérez-Villa
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
| | - Patricia Guevara-Ramírez
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
| | | | | | | | - Nelson Varela
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology, Faculty of Medicine, University of Chile, 8320000, Santiago, Chile
| | - Santiago Guerrero
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28015, Madrid, Spain.
- Laboratorio de Ciencia de Datos Biomédicos, Escuela de Medicina, Facultad de Ciencias Médicas de la Salud y de la Vida, Universidad Internacional del Ecuador, 170113, Quito, Ecuador.
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Ortiz-Prado E, Cordovez SP, Vasconez E, Viscor G, Roderick P. Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review. BMJ Open 2022; 12:e051777. [PMID: 35487749 PMCID: PMC9058702 DOI: 10.1136/bmjopen-2021-051777] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION About 5.7% of the world population resides above 1500 m. It has been hypothesised that acute exposure to high-altitude locations can increase stroke risk, while chronic hypoxia can reduce stroke-related mortality. OBJECTIVE This review aims to provide an overview of the available evidence on the association between long-term high-altitude exposure and ischaemic stroke. DESIGN A systematic review was performed from 1 January 1960 to 1 December 2021 to assess the possible link between high-altitude exposure and ischaemic stroke. The AMED, EMBASE, Cochrane Library, PubMed, MEDLINE, the Europe PubMed Central and the Latin-American bibliographic database Scielo were accessed using the University of Southampton library tool Delphis. In this review, we included population and individual-based observational studies, including cross-sectional and longitudinal studies except for those merely descriptive individual-based case reports. Studies were limited to humans living or visiting high-altitude locations for at least 28 days as a cut-off point for chronic exposure. RESULTS We reviewed a total of 1890 abstracts retrieved during the first step of the literature review process. The authors acquired in full text as potentially relevant 204 studies. Only 17 documents met the inclusion criteria and were finally included. Ten studies clearly suggest that living at high altitudes may be associated with an increased risk of stroke; however, five studies suggest that altitude may act as a protective factor for the development of stroke, while two studies report ambiguous results. CONCLUSIONS This review suggests that the most robust studies are more likely to find that prolonged living at higher altitudes reduces the risk of developing stroke or dying from it. Increased irrigation due to angiogenesis and increased vascular perfusion might be the reason behind improved survival profiles among those living within this altitude range. In contrast, residing above 3500 m seems to be associated with an apparent increased risk of developing stroke, probably linked to the presence of polycythaemia and other associated factors such as increased blood viscosity.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, Barcelona, Spain
| | - Simone Pierina Cordovez
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
- Facultad de Medicina, Universidad San Gregorio de Portoviejo, Portoviejo, Manabi, Ecuador
| | - Eduardo Vasconez
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
| | - Ginés Viscor
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, Barcelona, Spain
| | - Paul Roderick
- Faculty of Medicine, University of Southampton, Southampton, UK
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11
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High-altitude is associated with better short-term survival in critically ill COVID-19 patients admitted to the ICU. PLoS One 2022; 17:e0262423. [PMID: 35358185 PMCID: PMC8970356 DOI: 10.1371/journal.pone.0262423] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 12/26/2021] [Indexed: 01/08/2023] Open
Abstract
Background Multiple studies have attempted to elucidate the relationship between chronic hypoxia and SARS-CoV-2 infection. It seems that high-altitude is associated with lower COVID-19 related mortality and incidence rates; nevertheless, all the data came from observational studies, being this the first one looking into prospectively collected clinical data from severely ill patients residing at two significantly different altitudes. Methods A prospective cohort, a two-center study among COVID-19 confirmed adult patients admitted to a low (sea level) and high-altitude (2,850 m) ICU unit in Ecuador was conducted. Two hundred and thirty confirmed patients were enrolled from March 15th to July 15th, 2020. Results From 230 patients, 149 were men (64.8%) and 81 women (35.2%). The median age of all the patients was 60 years, and at least 105 (45.7%) of patients had at least one underlying comorbidity, including hypertension (33.5%), diabetes (16.5%), and chronic kidney failure (5.7%). The APACHE II scale (Score that estimates ICU mortality) at 72 hours was especially higher in the low altitude group with a median of 18 points (IQR: 9.5–24.0), compared to 9 points (IQR: 5.0–22.0) obtained in the high-altitude group. There is evidence of a difference in survival in favor of the high-altitude group (p = 0.006), the median survival being 39 days, compared to 21 days in the low altitude group. Conclusion There has been a substantial improvement in survival amongst people admitted to the high-altitude ICU. Residing at high-altitudes was associated with improved survival, especially among patients with no comorbidities. COVID-19 patients admitted to the high-altitude ICU unit have improved severity-of-disease classification system scores at 72 hours.
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12
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Herculano-Houzel S, Rothman DL. From a Demand-Based to a Supply-Limited Framework of Brain Metabolism. Front Integr Neurosci 2022; 16:818685. [PMID: 35431822 PMCID: PMC9012138 DOI: 10.3389/fnint.2022.818685] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/10/2022] [Indexed: 12/20/2022] Open
Abstract
What defines the rate of energy use by the brain, as well as per neurons of different sizes in different structures and animals, is one fundamental aspect of neuroscience for which much has been theorized, but very little data are available. The prevalent theories and models consider that energy supply from the vascular system to different brain regions is adjusted both dynamically and in the course of development and evolution to meet the demands of neuronal activity. In this perspective, we offer an alternative view: that regional rates of energy use might be mostly constrained by supply, given the properties of the brain capillary network, the highly stable rate of oxygen delivery to the whole brain under physiological conditions, and homeostatic constraints. We present evidence that these constraints, based on capillary density and tissue oxygen homeostasis, are similar between brain regions and mammalian species, suggesting they derive from fundamental biophysical limitations. The same constraints also determine the relationship between regional rates of brain oxygen supply and usage over the full physiological range of brain activity, from deep sleep to intense sensory stimulation, during which the apparent uncoupling of blood flow and oxygen use is still a predicted consequence of supply limitation. By carefully separating "energy cost" into energy supply and energy use, and doing away with the problematic concept of energetic "demands," our new framework should help shine a new light on the neurovascular bases of metabolic support of brain function and brain functional imaging. We speculate that the trade-offs between functional systems and even the limitation to a single attentional spot at a time might be consequences of a strongly supply-limited brain economy. We propose that a deeper understanding of brain energy supply constraints will provide a new evolutionary understanding of constraints on brain function due to energetics; offer new diagnostic insight to disturbances of brain metabolism; lead to clear, testable predictions on the scaling of brain metabolic cost and the evolution of brains of different sizes; and open new lines of investigation into the microvascular bases of progressive cognitive loss in normal aging as well as metabolic diseases.
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Affiliation(s)
- Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN, United States,Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States,*Correspondence: Suzana Herculano-Houzel,
| | - Douglas L. Rothman
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States,Department of Biomedical Engineering, Yale University, New Haven, CT, United States,Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
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13
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Ortiz-Prado E, Fernandez Naranjo RP, Vasconez E, Simbaña-Rivera K, Correa-Sancho T, Lister A, Calvopiña M, Viscor G. Analysis of Excess Mortality Data at Different Altitudes During the COVID-19 Outbreak in Ecuador. High Alt Med Biol 2021; 22:406-416. [PMID: 34905395 DOI: 10.1089/ham.2021.0070] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ortiz-Prado, Esteban, Raul Patricio Fernandez Naranjo, Eduardo Vasconez, Katherine Simbaña-Rivera, Trigomar Correa-Sancho, Alex Lister, Manuel Calvopiña, and Ginés Viscor. Analysis of excess mortality data at different altitudes during the COVID-19 outbreak in Ecuador. High Alt Med Biol. 22:406-416, 2021. Background: It has been speculated that living at high altitude confers some risk reduction in terms of SARS-CoV-2 infection, reduced transmissibility, and arguable lower COVID-19-related mortality. Objective: We aim to determine the number of excess deaths reported in Ecuador during the first year of the COVID-19 pandemic in relation to different altitude categories among 221 cantons in Ecuador, ranging from sea level to 4,300 m above. Methods: A descriptive ecological country-wide analysis of the excess mortality in Ecuador was performed since March 1, 2020, to March 1, 2021. Every canton was categorized as lower (for altitudes 2,500 m or less) or higher (for altitudes >2,500 m) in a first broad classification, as well as in two different classifications: The one proposed by Imray et al. in 2011 (low altitude <1,500 m, moderate altitude 1,500-2,500 m, high altitude 2,500-3,500 m, or very high altitude 3,500-5,500 m) and the one proposed by Bärtsch et al. in 2008 (near sea level 0-500 m, low altitude 500-2,000 m, moderate altitude 2,000-3,000 m, high altitude 3,000-5,500 m, and extreme altitude 5,500 m). A Poisson fitting analysis was used to identify trends on officially recorded all-caused deaths and those attributed to COVID-19. Results: In Ecuador, at least 120,573 deaths were recorded during the first year of the pandemic, from which 42,453 were catalogued as excessive when compared with the past 3 years of averages (2017-2019). The mortality rate at the lower altitude was 301/100,000 people, in comparison to 242/100,000 inhabitants in elevated cantons. Considering the four elevation categories, the highest excess deaths came from towns located at low altitude (324/100,000), in contrast to the moderate altitude (171/100,000), high-altitude (249/100,000), and very high-altitude (153/100,000) groups. Conclusions: This is the first report on COVID-19 excess mortality in a high-altitude range from 0 to 4,300 m above sea level. We found that absolute COVID-19-related excess mortality is lower both in time and in proportion in the cantons located at high and very high altitude when compared with those cantons located at low altitude.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador.,Department of Cell Biology, Physiology and Immunology of the Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
| | | | - Eduardo Vasconez
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | | | - Trigomar Correa-Sancho
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | - Alex Lister
- University Hospital Southampton NHS FT, Southampton, United Kingdom
| | - Manuel Calvopiña
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | - Ginés Viscor
- Department of Cell Biology, Physiology and Immunology of the Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
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14
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Okazaki N, Lankadeva YR, Peiris RM, Birchall IE, May CN. Rapid and persistent decrease in brain tissue oxygenation in ovine gram-negative sepsis. Am J Physiol Regul Integr Comp Physiol 2021; 321:R990-R996. [PMID: 34786976 DOI: 10.1152/ajpregu.00184.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The changes in brain perfusion and oxygenation in critical illness, which are thought to contribute to brain dysfunction, are unclear due to the lack of methods to measure these variables. We have developed a technique to chronically measure cerebral tissue perfusion and oxygen tension in unanesthetized sheep. Using this technique, we have determined the changes in cerebral perfusion and Po2 during the development of ovine sepsis. In adult Merino ewes, fiber-optic probes were implanted in the brain, renal cortex, and renal medulla to measure tissue perfusion, oxygen tension (Po2), and temperature, and flow probes were implanted on the pulmonary and renal arteries. Conscious sheep were infused with live Escherichia coli for 24 h, which induced hyperdynamic sepsis; mean arterial pressure decreased (from 85.2 ± 5.6 to 71.5 ± 8.7 mmHg), while cardiac output (from 4.12 ± 0.70 to 6.15 ± 1.26 L/min) and total peripheral conductance (from 48.9 ± 8.5 to 86.8 ± 11.5 mL/min/mmHg) increased (n = 8, all P < 0.001) and arterial Po2 decreased (from 104 ± 8 to 83 ± 10 mmHg; P < 0.01). Cerebral perfusion tended to decrease acutely, although this did not reach significance, but there was a significant and sustained decrease in cerebral tissue Po2 (from 32.2 ± 10.1 to 18.8 ± 11.7 mmHg) after 3 h and to 22.8 ± 5.2 mmHg after 24 h of sepsis (P < 0.02). Sepsis induced large reductions in both renal medullary perfusion and Po2 but had no effect in the renal cortex. In ovine sepsis, there is an early decrease in cerebral Po2 that is maintained for 24 h despite minimal changes in cerebral perfusion. Cerebral hypoxia may be one of the factors causing sepsis-induced malaise and lethargy.
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Affiliation(s)
- Nobuki Okazaki
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.,Department of Anesthesiology and Resuscitology, Okayama University, Okayama, Japan
| | - Yugeesh R Lankadeva
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Rachel M Peiris
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Ian E Birchall
- Neuropathology Laboratory, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Clive N May
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
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15
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Ortiz-Prado E, Espinosa PS, Borrero A, Cordovez SP, Vasconez JE, Barreto-Grimales A, Coral-Almeida M, Henriquez-Trujillo AR, Simbaña-Rivera K, Gomez-Barreno L, Viscor G, Roderick P. Stroke-Related Mortality at Different Altitudes: A 17-Year Nationwide Population-Based Analysis From Ecuador. Front Physiol 2021; 12:733928. [PMID: 34675818 PMCID: PMC8525493 DOI: 10.3389/fphys.2021.733928] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/08/2021] [Indexed: 12/23/2022] Open
Abstract
Introduction: Worldwide, more than 5.7% of the population reside above 1,500 m of elevation. It has been hypothesized that acute short-term hypoxia exposure could increase the risk of developing a stroke. Studies assessing the effect of altitude on stroke have provided conflicting results, some analyses suggest that long-term chronic exposure could be associated with reduced mortality and lower stroke incidence rates. Methods: An ecological analysis of all stroke hospital admissions, mortality rates, and disability-adjusted life years in Ecuador was performed from 2001 to 2017. The cases and population at risk were categorized in low (<1,500 m), moderate (1,500–2,500 m), high (2,500–3,500 m), and very high altitude (3,500–5,500 m) according to the place of residence. The derived crude and direct standardized age-sex adjusted mortality and hospital admission rates were calculated. Results: A total of 38,201 deaths and 75,893 stroke-related hospital admissions were reported. High altitude populations (HAP) had lower stroke mortality in men [OR: 0.91 (0.88–0.95)] and women [OR: 0.83 (0.79–0.86)]. In addition, HAP had a significant lower risk of getting admitted to the hospital when compared with the low altitude group in men [OR: 0.55 (CI 95% 0.54–0.56)] and women [OR: 0.65 (CI 95% 0.64–0.66)]. Conclusion: This is the first epidemiological study that aims to elucidate the association between stroke and altitude using four different elevation ranges. Our findings suggest that living at higher elevations offers a reduction or the risk of dying due to stroke as well as a reduction in the probability of being admitted to the hospital. Nevertheless, this protective factor has a stronger effect between 2,000 and 3,500 m.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador.,Departamento de Biología Celular, Fisiología e Inmunología, Universitat de Barcelona, Barcelona, Spain
| | - Patricio S Espinosa
- Neurology, Marcus Neuroscience Institute, Boca Raton Regional Hospital, Boca Raton, FL, United States
| | - Alfredo Borrero
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Simone P Cordovez
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Jorge E Vasconez
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | | | - Marco Coral-Almeida
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | | | | | - Lenin Gomez-Barreno
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Gines Viscor
- Departamento de Biología Celular, Fisiología e Inmunología, Universitat de Barcelona, Barcelona, Spain
| | - Paul Roderick
- Faculty of Medicine, School of Primary Care, Population Sciences and Medical Education, University of Southampton, Southampton, United Kingdom
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16
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Farrell JS, Colangeli R, Dong A, George AG, Addo-Osafo K, Kingsley PJ, Morena M, Wolff MD, Dudok B, He K, Patrick TA, Sharkey KA, Patel S, Marnett LJ, Hill MN, Li Y, Teskey GC, Soltesz I. In vivo endocannabinoid dynamics at the timescale of physiological and pathological neural activity. Neuron 2021; 109:2398-2403.e4. [PMID: 34352214 PMCID: PMC8351909 DOI: 10.1016/j.neuron.2021.05.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/06/2021] [Accepted: 05/19/2021] [Indexed: 10/20/2022]
Abstract
The brain's endocannabinoid system is a powerful controller of neurotransmitter release, shaping synaptic communication under physiological and pathological conditions. However, our understanding of endocannabinoid signaling in vivo is limited by the inability to measure their changes at timescales commensurate with the high lability of lipid signals, leaving fundamental questions of whether, how, and which endocannabinoids fluctuate with neural activity unresolved. Using novel imaging approaches in awake behaving mice, we now demonstrate that the endocannabinoid 2-arachidonoylglycerol, not anandamide, is dynamically coupled to hippocampal neural activity with high spatiotemporal specificity. Furthermore, we show that seizures amplify the physiological endocannabinoid increase by orders of magnitude and drive the downstream synthesis of vasoactive prostaglandins that culminate in a prolonged stroke-like event. These results shed new light on normal and pathological endocannabinoid signaling in vivo.
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Affiliation(s)
- Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
| | - Roberto Colangeli
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Ao Dong
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-THU Center for Life Sciences, IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Antis G George
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kwaku Addo-Osafo
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Philip J Kingsley
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Maria Morena
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Marshal D Wolff
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Kaikai He
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-THU Center for Life Sciences, IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Toni A Patrick
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Keith A Sharkey
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Sachin Patel
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lawrence J Marnett
- A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Matthew N Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Yulong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-THU Center for Life Sciences, IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - G Campbell Teskey
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
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17
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Gom RC, Bhatt D, Villa BR, George AG, Lohman AW, Mychasiuk R, Rho JM, Teskey GC. The ketogenic diet raises brain oxygen levels, attenuates postictal hypoxia, and protects against learning impairments. Neurobiol Dis 2021; 154:105335. [PMID: 33741453 DOI: 10.1016/j.nbd.2021.105335] [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: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/14/2021] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVES A prolonged vasoconstriction/hypoperfusion/hypoxic event follows self-terminating focal seizures. The ketogenic diet (KD) has demonstrated efficacy as a metabolic treatment for intractable epilepsy and other disorders but its effect on local brain oxygen levels is completely unknown. This study investigated the effects of the KD on tissue oxygenation in the hippocampus before and after electrically elicited (kindled) seizures and whether it could protect against a seizure-induced learning impairment. We also examined the effects of the ketone β-hydroxybutyrate (BHB) as a potential underlying mechanism. METHODS Male and female rats were given access to one of three diet protocols 2 weeks prior to the initiation of seizures: KD, caloric restricted standard chow, and ad libitum standard chow. Dorsal hippocampal oxygen levels were measured prior to initiation of diets as well as before and after a 10-day kindling paradigm. Male rats were then tested on a novel object recognition task to assess postictal learning impairments. In a separate cohort, BHB was administered 30 min prior to seizure elicitation to determine whether it influenced oxygen dynamics. RESULTS The KD increased dorsal hippocampal oxygen levels, ameliorated postictal hypoxia, and prevented postictal learning impairments. Acute BHB administration did not alter oxygen levels before or after seizures. INTERPRETATION The ketogenic diet raised brain oxygen levels and attenuated severe postictal hypoxia likely through a mechanism independent of ketosis and shows promise as a non-pharmacological treatment to prevent the postictal state.
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Affiliation(s)
- Renaud C Gom
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada.
| | - Dhyey Bhatt
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Bianca R Villa
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Antis G George
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Alexander W Lohman
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Jong M Rho
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Cumming School of Medicine University of Calgary, Calgary, CA, Canada; Departments of Neurosciences and Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, California, USA
| | - G Campbell Teskey
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
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18
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Abstract
Over the last few years, cancer immunotherapy experienced tremendous developments and it is nowadays considered a promising strategy against many types of cancer. However, the exclusion of lymphocytes from the tumor nest is a common phenomenon that limits the efficiency of immunotherapy in solid tumors. Despite several mechanisms proposed during the years to explain the immune excluded phenotype, at present, there is no integrated understanding about the role played by different models of immune exclusion in human cancers. Hypoxia is a hallmark of most solid tumors and, being a multifaceted and complex condition, shapes in a unique way the tumor microenvironment, affecting gene transcription and chromatin remodeling. In this review, we speculate about an upstream role for hypoxia as a common biological determinant of immune exclusion in solid tumors. We also discuss the current state of ex vivo and in vivo imaging of hypoxic determinants in relation to T cell distribution that could mechanisms of immune exclusion and discover functional-morphological tumor features that could support clinical monitoring.
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19
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Lee K, Bohnert S, Vair C, Mikler J, Dunn JF. Cerebral blood flow and oxygenation in rat brain after soman exposure. Toxicol Lett 2021; 336:50-56. [PMID: 33147512 DOI: 10.1016/j.toxlet.2020.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 08/14/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Abstract
Nerve agent exposure can cause debilitating neurological damage even with treatment. Currently accepted treatments involve attenuating the cholinergic crisis and seizure onset but do not focus directly on neuroprotection. Hence, there is a need for improved treatments to reduce neurological deficits. It is important to understand the pathophysiology of nerve agent mediated injury in order to identify effective treatment targets. Nerve agent-induced seizures are believed to be the main contributor to the neuropathology. Recently seizures have been shown to cause vascular changes that may actually attenuate neurological damage. This study evaluated the effect of soman-induced convulsive seizures on the relationship between CNS oxygen consumption and supply. To simultaneously assess changes in oxygenation and perfusion, rats were implanted with permanently fixed fiber-optic tissue oxygen sensing probes in the motor cortex and imaged with continuous arterial spin labelling MRI to measure cerebral blood flow. Baseline tissue oxygen tension (ptO2) and cerebral blood flow (CBF) were measured in isoflurane anaesthetized rats at least one day prior to soman or saline exposure. Rats were pretreated with HI-6 dimethansulfonate and atropine methyl nitrate (125 mg/kg and 20 mg/kg; intraperitoneal) followed by a convulsive dose of soman (90 μg/kg; subcutaneous) or equal volume of saline. Three additional treatments of HI-6/AMN were administered to improve survival. At 1.5 -hs after exposure, ptO2 and cerebral blood flow measurements were conducted. There was a significant decrease in CBF 1.5 -hs following soman exposure but no change in ptO2 was found. When we correlated ptO2 and CBF, for a given ptO2, there was lower CBF following soman exposure. This may indicate metabolism is inhibited, possibly because of mitochondrial impairment, therefore reducing oxygen demand. These data show hypoperfusion in brain following soman exposure which would be expected to contribute to soman-related neuropathology.
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Affiliation(s)
- Kevin Lee
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sara Bohnert
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - Cory Vair
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - John Mikler
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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20
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Tran CHT, George AG, Teskey GC, Gordon GR. Seizures elevate gliovascular unit Ca2+ and cause sustained vasoconstriction. JCI Insight 2020; 5:136469. [PMID: 33004688 PMCID: PMC7566700 DOI: 10.1172/jci.insight.136469] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/20/2020] [Indexed: 12/31/2022] Open
Abstract
Seizures can result in a severe hypoperfusion/hypoxic attack that causes postictal memory and behavioral impairments. However, neither postictal changes to microvasculature nor Ca2+ changes in key cell types controlling blood perfusion have been visualized in vivo, leaving essential components of the underlying cellular mechanisms unclear. Here, we use 2-photon microvascular and Ca2+ imaging in awake mice to show that seizures result in a robust vasoconstriction of cortical penetrating arterioles, which temporally mirrors the prolonged postictal hypoxia. The vascular effect was dependent on cyclooxygenase 2, as pretreatment with ibuprofen prevented postictal vasoconstriction. Moreover, seizures caused a rapid elevation in astrocyte endfoot Ca2+ that was confined to the seizure period, and vascular smooth muscle cells displayed a significant increase in Ca2+ both during and following seizures, lasting up to 75 minutes. Our data show enduring postictal vasoconstriction and temporal activities of 2 cell types within the neurovascular unit that are associated with seizure-induced hypoperfusion/hypoxia. These findings support prevention of this event may be a novel and tractable treatment strategy in patients with epilepsy who experience extended postseizure impairments. Seizures cause enduring microvascular constriction via long lasting calcium elevations in vascular smooth muscle cells.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute and.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Antis G George
- Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute and.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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21
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Wolff MD, Farrell JS, Scantlebury MH, Teskey GC. Dynamic oxygen changes during status epilepticus and subsequent endogenous kindling. Epilepsia 2020; 61:1515-1527. [PMID: 32478859 PMCID: PMC7496277 DOI: 10.1111/epi.16554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Brain tissue oxygen (partial oxygen pressure [pO2 ]) levels are tightly regulated to stay within the normoxic zone, with deviations on either side resulting in impaired brain function. Whereas pathological events such as ischemic attacks and brief seizures have previously been shown to result in pO2 levels well below the normoxic zone, oxygen levels during prolonged status epilepticus (SE) and the subsequent endogenous kindling period are unknown. METHODS We utilized two models of acquired temporal lobe epilepsy in rats: intrahippocampal kainic acid infusion and prolonged perforant pathway stimulation. Local tissue oxygen was measured in the dorsal hippocampus using an optode during and for several weeks following SE. RESULTS We observed hyperoxia in the hippocampus during induced SE in both models. Following termination of SE, 88% of rats initiated focal self-generated spiking activity in the hippocampus within the first 7 days, which was associated with dynamic oxygen changes. Self-generated and recurring epileptiform activity subsequently organized into higher-frequency bursts that became progressively longer and were ultimately associated with behavioral seizures that became more severe with time and led to postictal hypoxia. SIGNIFICANCE Induced SE and self-generated recurrent epileptiform activity can have profound and opposing effects on brain tissue oxygenation that may serve as a biomarker for ongoing pathological activity in the brain.
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Affiliation(s)
- Marshal D. Wolff
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
| | - Jordan S. Farrell
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Department of NeurosurgeryStanford UniversityStanfordCaliforniaUSA
| | - Morris H. Scantlebury
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Departments of Pediatrics and Clinical NeurosciencesUniversity of CalgaryCalgaryAlbertaCanada
- Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryAlbertaCanada
| | - G. Campbell Teskey
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryAlbertaCanada
- Alberta Children's Hospital Research InstituteUniversity of CalgaryCalgaryAlbertaCanada
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22
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Mapping transient hypoxia from in situ activation of 15O by photon beams: A simulation study. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Phillips TJ, Gom RC, Wolff MD, Teskey GC. Caffeine Exacerbates Postictal Hypoxia. Neuroscience 2019; 422:32-43. [PMID: 31678341 DOI: 10.1016/j.neuroscience.2019.09.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 09/12/2019] [Accepted: 09/17/2019] [Indexed: 12/11/2022]
Abstract
A stroke-like event follows seizures which may be responsible for the postictal state and a contributing factor to the development of seizure-induced brain abnormalities and behavioral dysfunction associated with epilepsy. Caffeine is the world's most popular drug with ∼85% of people in the USA consuming it daily. Thus, persons with epilepsy are likely to have caffeine in their body and brain during seizures. This preclinical study investigated the effects of acute caffeine on local hippocampal tissue oxygenation pre and post seizure. We continuously measured local oxygen levels in the CA1 region of the hippocampus and utilized the electrical kindling model in rats. Rats were acutely administered either caffeine, or one of its metabolites, or agonists and antagonists at adenosine sub-receptor types or ryanodine receptors prior to the elicitation of seizures. Acute caffeine administration caused a significant drop in pre-seizure hippocampal pO2. Following a seizure, caffeine, as well as two of its metabolites paraxanthine, and theophylline, increased the time below the severe hypoxic threshold (10 mmHg). Likewise, the specific A2A receptor antagonist, SCH-58261, mimicked caffeine by causing a significant drop in pre-seizure pO2 and the area and time below the severe hypoxic threshold. Moreover, the A2A receptor agonist, CGS-21680 was able to prevent the effect of both caffeine and SCH-58261 adding further evidence that caffeine is likely acting through the A2A receptor. Clinical tracking and investigations are needed to determine the effect of caffeine on postictal symptomology and blood flow in persons with epilepsy.
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Affiliation(s)
- Thomas J Phillips
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Renaud C Gom
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Marshal D Wolff
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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24
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Chen NT, Barth ED, Lee TH, Chen CT, Epel B, Halpern HJ, Lo LW. Highly sensitive electron paramagnetic resonance nanoradicals for quantitative intracellular tumor oxymetric images. Int J Nanomedicine 2019; 14:2963-2971. [PMID: 31118615 PMCID: PMC6503311 DOI: 10.2147/ijn.s194779] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/11/2019] [Indexed: 01/25/2023] Open
Abstract
Purpose: Tumor oxygenation is a critical parameter influencing the efficacy of cancer therapy. Low levels of oxygen in solid tumor have been recognized as an indicator of malignant progression and metastasis, as well as poor response to chemo- and radiation therapy. Being able to measure oxygenation for an individual's tumor would provide doctors with a valuable way of identifying optimal treatments for patients. Methods: Electron paramagnetic resonance imaging (EPRI) in combination with an oxygen-measuring paramagnetic probe was performed to measure tumor oxygenation in vivo. Triarylmethyl (trityl) radical exhibits high specificity, sensitivity, and resolution for quantitative measurement of O2 concentration. However, its in vivo applications in previous studies have been limited by the required high dosage, its short half-life, and poor intracellular permeability. To address these limitations, we developed high-capacity nanoformulated radicals that employed fluorescein isothiocyanate-labeled mesoporous silica nanoparticles (FMSNs) as trityl radical carriers. The high surface area nanostructure and easy surface modification of physiochemical properties of FMSNs enable efficient targeted delivery of highly concentrated, nonself-quenched trityl radicals, protected from environmental degradation and dilution. Results: We successfully designed and synthesized a tumor-targeted nanoplatform as a carrier for trityl. In addition, the nanoformulated trityl does not affect oxygen-sensing capacity by a self-relaxation or broadening effect. The FMSN-trityl exhibited high sensitivity/response to oxygen in the partial oxygen pressure range from 0 to 155 mmHg. Furthermore, MSN-trityl displayed outstanding intracellular oxygen mapping in both in vitro and in vivo animal studies. Conclusion: The highly sensitive nanoformulated trityl spin probe can profile intracellular oxygen distributions of tumor in a real-time and quantitative manner using in vivo EPRI.
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Affiliation(s)
- Nai-Tzu Chen
- Institute of New Drug Development, China Medical University, Taichung 40402, Taiwan
| | - Eugene D Barth
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Tsung-Hsi Lee
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Howard J Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Leu-Wei Lo
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA.,Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 35053, Taiwan
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25
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Ortiz-Prado E, Dunn JF, Vasconez J, Castillo D, Viscor G. Partial pressure of oxygen in the human body: a general review. AMERICAN JOURNAL OF BLOOD RESEARCH 2019; 9:1-14. [PMID: 30899601 PMCID: PMC6420699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 12/23/2018] [Indexed: 06/09/2023]
Abstract
The human body is a highly aerobic organism, in which it is necessary to match oxygen supply at tissue levels to the metabolic demands. Along metazoan evolution, an exquisite control developed because although oxygen is required as the final acceptor of electron respiratory chain, an excessive level could be potentially harmful. Understanding the role of the main factors affecting oxygen availability, such as the gradient of pressure of oxygen during normal conditions, and during hypoxia is an important point. Several factors such as anaesthesia, hypoxia, and stress affect the regulation of the atmospheric, alveolar, arterial, capillary and tissue partial pressure of oxygen (PO2). Our objective is to offer to the reader a summarized and practical appraisal of the mechanisms related to the oxygen's supply within the human body, including a facilitated description of the gradient of pressure from the atmosphere to the cells. This review also included the most relevant measuring methods of PO2 as well as a practical overview of its reference values in several tissues.
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Affiliation(s)
- Esteban Ortiz-Prado
- OneHealth Research Group, Universidad De Las AmericasQuito, Ecuador
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Universitat de BarcelonaBarcelona, Spain
| | - Jeff F Dunn
- Cumming School of Medicine, University of CalgaryCalgary, Canada
| | - Jorge Vasconez
- OneHealth Research Group, Universidad De Las AmericasQuito, Ecuador
| | - Diana Castillo
- OneHealth Research Group, Universidad De Las AmericasQuito, Ecuador
| | - Ginés Viscor
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Universitat de BarcelonaBarcelona, Spain
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26
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Keeley TP, Mann GE. Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans. Physiol Rev 2019; 99:161-234. [PMID: 30354965 DOI: 10.1152/physrev.00041.2017] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The extensive oxygen gradient between the air we breathe (Po2 ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognized that cell culture undertaken under room air conditions falls short of replicating this protection in vitro. Despite this, difficulty in accurately determining the appropriate O2 levels in which to culture cells, coupled with a lack of the technology to replicate and maintain a physiological O2 environment in vitro, has hindered addressing this issue thus far. In this review, we aim to address the current understanding of tissue Po2 distribution in vivo and summarize the attempts made to replicate these conditions in vitro. The state-of-the-art techniques employed to accurately determine O2 levels, as well as the issues associated with reproducing physiological O2 levels in vitro, are also critically reviewed. We aim to provide the framework for researchers to undertake cell culture under O2 levels relevant to specific tissues and organs. We envisage that this review will facilitate a paradigm shift, enabling translation of findings under physiological conditions in vitro to disease pathology and the design of novel therapeutics.
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Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
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27
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Assessment of brain oxygenation imbalance following soman exposure in rats. Neurotoxicology 2018; 65:28-37. [PMID: 29378300 DOI: 10.1016/j.neuro.2018.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 10/18/2022]
Abstract
Nerve agents (NAs) are potent organophosphorus (OP) compounds with applications in chemical warfare. OP compounds act by inhibiting acetylcholinesterase (AChE). Soman (O-pinacolyl methylphosphonofluoridate) is one of the most potent NAs. It is well known that small doses of NAs can be lethal, and that even non-lethal exposure leads to long-term mental debilitation/neurological damage. However, the neuropathology following exposure to sub-lethal nerve agents is not well understood. In this study, we examined changes in tissue oxygenation (pO2) in the cortex and hippocampus after a sub-lethal dose of soman [80-90 μg/kg; subcutaneous]. pO2 changes can provide information regarding oxygen delivery and utilization and may be indicative of a disruption in cerebral blood flow and/or metabolism. Changes in oxygenation were measured with chronically implanted oxygen sensors in awake and freely moving rats. Measurements were taken before, during, and after soman-induced convulsive seizures. Soman exposure resulted in an immediate increase in pO2 in the cortex, followed by an even greater increase that precedes the onset of soman-induced convulsive seizures. The rise in hippocampus pO2 was delayed relative to the cortex, although the general pattern of brain oxygenation between these two regions was similar. After convulsive seizures began, pO2 levels declined but usually remained hyperoxygenated. Following the decline in pO2, low frequency cycles of large amplitude changes were observed in both the cortex and hippocampus. This pattern is consistent with recurring seizures. Measuring real-time changes in brain pO2 provides new information on the physiological status of the brain following soman exposure. These results highlight that the measurement of brain oxygenation could provide a sensitive marker of nerve agent exposure and serve as a biomarker for treatment studies.
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28
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Ledo A, Lourenço CF, Laranjinha J, Gerhardt GA, Barbosa RM. Combined in Vivo Amperometric Oximetry and Electrophysiology in a Single Sensor: A Tool for Epilepsy Research. Anal Chem 2017; 89:12383-12390. [DOI: 10.1021/acs.analchem.7b03452] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Ana Ledo
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- BrainSense, Limitada, Biocant Park, 3060-197 Cantanhede, Portugal
| | - Cátia F. Lourenço
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
| | - João Laranjinha
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Faculty
of Pharmacy, University of Coimbra, Azinhaga de Santa Coimbra, 3000-548 Coimbra, Portugal
| | - Greg A. Gerhardt
- Center for Microelectrode
Technology, Department of Neuroscience, University of Kentucky Medical Center, Lexington, Kentucky 40536, United States
| | - Rui M. Barbosa
- Center
for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Faculty
of Pharmacy, University of Coimbra, Azinhaga de Santa Coimbra, 3000-548 Coimbra, Portugal
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29
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Solis E, Cameron-Burr KT, Kiyatkin EA. Rapid Physiological Fluctuations in Nucleus Accumbens Oxygen Levels Induced by Arousing Stimuli: Relationships with Changes in Brain Glucose and Metabolic Neural Activation. Front Integr Neurosci 2017; 11:9. [PMID: 28484378 PMCID: PMC5401908 DOI: 10.3389/fnint.2017.00009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/06/2017] [Indexed: 01/01/2023] Open
Abstract
Proper entry of oxygen from arterial blood into the brain is essential for maintaining brain metabolism under normal conditions and during functional neural activation. However, little is known about physiological fluctuations in brain oxygen and their underlying mechanisms. To address this issue, we employed high-speed amperometry with platinum oxygen sensors in freely moving male rats. Recordings were conducted in the nucleus accumbens (NAc), a critical structure for sensorimotor integration. Rats were exposed to arousing stimuli of different nature (brief auditory tone, a 1-min novel object presentation, a 3-min social interaction with a conspecific, and a 3-min tail-pinch). We found that all arousing stimuli increased NAc oxygen levels. Increases were rapid (4–10-s onset latencies), modest in magnitude (1–3 μM or 5%–15% over baseline) and duration (5–20 min), and generally correlated with the arousing potential of each stimulus. Two strategies were used to determine the mechanisms underlying the observed increases in NAc oxygen levels. First, we showed that NAc oxygen levels phasically increase following intra-NAc microinjections of glutamate (GLU) that excite accumbal neurons. Therefore, local neural activation with subsequent local vasodilation is involved in mediating physiological increases in NAc oxygen induced by arousing stimuli. Second, by employing oxygen monitoring in the subcutaneous space, a highly-vascularized area with no metabolic activity, we determined that physiological increases in NAc oxygen also depend on the rise in blood oxygen levels caused by respiratory activation. Due to the co-existence of different mechanisms governing oxygen entry into brain tissue, NAc oxygen responses differ from fluctuations in NAc glucose, which, within a normal behavioral continuum, are regulated exclusively by neuro-vascular coupling due to glucose’s highly stable levels in the blood. Finally, we discuss the relationships between physiological fluctuations in NAc oxygen, glucose and metabolic brain activation assessed by intra-brain heat production.
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Affiliation(s)
- Ernesto Solis
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
| | - Keaton T Cameron-Burr
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
| | - Eugene A Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
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30
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Farrell JS, Wolff MD, Teskey GC. Neurodegeneration and Pathology in Epilepsy: Clinical and Basic Perspectives. ADVANCES IN NEUROBIOLOGY 2017; 15:317-334. [PMID: 28674987 DOI: 10.1007/978-3-319-57193-5_12] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Epilepsy is commonly associated with a number of neurodegenerative and pathological alterations in those areas of the brain that are involved in repeated electrographic seizures. These most prominently include neuron loss and an increase in astrocyte number and size but may also include enhanced blood-brain barrier permeability, the formation of new capillaries, axonal sprouting, and central inflammation. In animal models in which seizures are either repeatedly elicited or are self-generated, a similar set of neurodegenerative and pathological alterations in brain anatomy are observed. The primary causal agent responsible for these alterations may be the cascade of events that follow a seizure and lead to an hypoperfusion/hypoxic episode. While epilepsy has long and correctly been considered an electrical disorder, the vascular system likely plays an important causal role in the neurodegeneration and pathology that occur as a consequence of repeated seizures.
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Affiliation(s)
- Jordan S Farrell
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Marshal D Wolff
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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31
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Gray Matter Hypoxia in the Brain of the Experimental Autoimmune Encephalomyelitis Model of Multiple Sclerosis. PLoS One 2016; 11:e0167196. [PMID: 27907119 PMCID: PMC5131950 DOI: 10.1371/journal.pone.0167196] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 11/10/2016] [Indexed: 12/30/2022] Open
Abstract
Background Multiple sclerosis (MS) has a significant inflammatory component and may have significant gray matter (GM) pathophysiology. Brain oxygenation is a sensitive measurement of the balance between metabolic need and oxygen delivery. There is evidence that inflammation and hypoxia are interdependent. In this paper, we applied novel, implanted PO2 sensors to measure hypoxia in cortical and cerebellar GM, in an inflammation-induced mouse model of MS. Objective Quantify oxygenation in cortical and cerebellar GM in the awake, unrestrained experimental autoimmune encephalomyelitis (EAE) mouse model and to relate the results to symptom level and disease time-course. Methods C57BL/6 mice were implanted with a fiber-optic sensor in the cerebellum (n = 13) and cortex (n = 24). Animals were induced with stimulation of the immune response and sensitization to myelin oligodendrocyte glycoprotein (MOG). Controls did not have MOG. We measured PO2 in awake, unrestrained animals from pre-induction (baseline) up to 36 days post-induction for EAE and controls. Results There were more days with hypoxia than hyperoxia (cerebellum: 34/67 vs. 18/67 days; cortex: 85/112 vs. 22/112) compared to time-matched controls. The average decline in PO2 on days that were significantly lower than time-matched controls was -8.8±6.0 mmHg (mean ± SD) for the cerebellum and -8.0±4.6 for the cortex. Conversely, the average increase in PO2 on days that were significantly hyperoxic was +3.2±2.8 mmHg (mean ± SD) for the cerebellum and +0.8±2.1 for the cortex. Cortical hypoxia related to increased behavioral deficits. Evidence for hypoxia occurred before measurable behavioral deficits. Conclusions A highly inflammatory condition primed to a white matter (WM) autoimmune response correlates with significant hypoxia and increased variation in oxygenation in GM of both cerebellum and cortex in the mouse EAE model of MS.
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32
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Farrell JS, Gaxiola-Valdez I, Wolff MD, David LS, Dika HI, Geeraert BL, Rachel Wang X, Singh S, Spanswick SC, Dunn JF, Antle MC, Federico P, Teskey GC. Postictal behavioural impairments are due to a severe prolonged hypoperfusion/hypoxia event that is COX-2 dependent. eLife 2016; 5:e19352. [PMID: 27874832 PMCID: PMC5154758 DOI: 10.7554/elife.19352] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/21/2016] [Indexed: 12/26/2022] Open
Abstract
Seizures are often followed by sensory, cognitive or motor impairments during the postictal phase that show striking similarity to transient hypoxic/ischemic attacks. Here we show that seizures result in a severe hypoxic attack confined to the postictal period. We measured brain oxygenation in localized areas from freely-moving rodents and discovered a severe hypoxic event (pO2 < 10 mmHg) after the termination of seizures. This event lasted over an hour, is mediated by hypoperfusion, generalizes to people with epilepsy, and is attenuated by inhibiting cyclooxygenase-2 or L-type calcium channels. Using inhibitors of these targets we separated the seizure from the resulting severe hypoxia and show that structure specific postictal memory and behavioral impairments are the consequence of this severe hypoperfusion/hypoxic event. Thus, epilepsy is much more than a disease hallmarked by seizures, since the occurrence of postictal hypoperfusion/hypoxia results in a separate set of neurological consequences that are currently not being treated and are preventable.
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Affiliation(s)
- Jordan S Farrell
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Ismael Gaxiola-Valdez
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Marshal D Wolff
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Laurence S David
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Haruna I Dika
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
- Department of Physiology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Bryce L Geeraert
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - X Rachel Wang
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Shaily Singh
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Simon C Spanswick
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Michael C Antle
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Paolo Federico
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
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Yu L, Wu Y, Dunn JF, Murari K. In-vivo monitoring of tissue oxygen saturation in deep brain structures using a single fiber optical system. BIOMEDICAL OPTICS EXPRESS 2016; 7:4685-4694. [PMID: 27896007 PMCID: PMC5119607 DOI: 10.1364/boe.7.004685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/05/2016] [Accepted: 10/13/2016] [Indexed: 05/05/2023]
Abstract
We propose a single fiber optical system for monitoring tissue oxygen saturation (sO2) based on continuous-wave reflectance spectroscopy in the visible wavelengths. The system is designed for measurements in deep brain structures by stereotaxically implanting the 200 μm-core fiber probe into the tissue of interest. Monte Carlo (MC) simulations were used to estimate the measurement tissue volume between 0.02-0.03 mm3. Experiments in an optical phantom indicated the system had a root mean squared error (RMSE) of 4.21% compared with a commercial fluorescence-based tissue oxygen partial pressure measuring system. Finally, we used the system for continuously monitoring tissue sO2 from a highly-localized volume in anesthetized mice.
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Affiliation(s)
- Linhui Yu
- Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary,
Canada
| | - Ying Wu
- Department of Radiology, Cumming School of Medicine, University of Calgary,
Canada
| | - Jeff F. Dunn
- Department of Radiology, Cumming School of Medicine, University of Calgary,
Canada
- Hotchkiss Brain Institute, University of Calgary,
Canada
- Experimental Imaging Centre, University of Calgary,
Canada
| | - Kartikeya Murari
- Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary,
Canada
- Hotchkiss Brain Institute, University of Calgary,
Canada
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Lyons DG, Parpaleix A, Roche M, Charpak S. Mapping oxygen concentration in the awake mouse brain. eLife 2016; 5. [PMID: 26836304 PMCID: PMC4775210 DOI: 10.7554/elife.12024] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/25/2016] [Indexed: 01/16/2023] Open
Abstract
Although critical for brain function, the physiological values of cerebral oxygen concentration have remained elusive because high-resolution measurements have only been performed during anesthesia, which affects two major parameters modulating tissue oxygenation: neuronal activity and blood flow. Using measurements of capillary erythrocyte-associated transients, fluctuations of oxygen partial pressure (Po2) associated with individual erythrocytes, to infer Po2 in the nearby neuropil, we report the first non-invasive micron-scale mapping of cerebral Po2 in awake, resting mice. Interstitial Po2 has similar values in the olfactory bulb glomerular layer and the somatosensory cortex, whereas there are large capillary hematocrit and erythrocyte flux differences. Awake tissue Po2 is about half that under isoflurane anesthesia, and within the cortex, vascular and interstitial Po2 values display layer-specific differences which dramatically contrast with those recorded under anesthesia. Our findings emphasize the importance of measuring energy parameters non-invasively in physiological conditions to precisely quantify and model brain metabolism. DOI:http://dx.doi.org/10.7554/eLife.12024.001 Brain cells need a constant supply of oxygen to fuel their activities. This oxygen is delivered by the flow of blood through the vessels in the brain. If the blood flow to brain tissue is cut off as happens in stroke, or if an individual stops breathing, the brain becomes deprived of oxygen and brain cells will be damaged and die. To better understand how the brain works in health and disease, scientists need to learn how much oxygen the blood must deliver to the brain tissue to adequately support the activities of brain cells. Many studies have measured oxygen levels in the brain. However, these studies have looked only roughly and taken measurements from large areas of the brain, or they have involved animals receiving anesthesia, which can alter blood flow and oxygen use in the brain. Recently, scientists discovered that they could measure oxygen concentration at high detail in the brain of anesthetized rodents with a specialized microscope, by using molecules that emit light at a rate that depends on the local oxygen concentration. Now, Lyons et al. have shown that this same technique can be used in mice that are awake. First, a piece of the skull was replaced with glass to create a small transparent window. Then, the animals were allowed to recover for a few weeks, and were trained to get them used to how they would be handled during the experiments. After this period, the oxygen concentrations and blood flow in different parts of the mouse brains were measured in fine detail using the microscope while the animals were awake and relaxed. The experiments showed that oxygen levels in awake resting mice are actually lower than in anesthetized mice, and that oxygen levels differ between different parts of the mouse brain. This first detailed look at oxygen levels in the brain of awake animals will likely lead to more studies. For example, future studies may look at how quickly the brain uses oxygen under normal conditions and what happens in the brain during disease. DOI:http://dx.doi.org/10.7554/eLife.12024.002
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Affiliation(s)
- Declan G Lyons
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Alexandre Parpaleix
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Morgane Roche
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Serge Charpak
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
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Bakmiwewa SM, Heng B, Guillemin GJ, Ball HJ, Hunt NH. An effective, low-cost method for achieving and maintaining hypoxia during cell culture studies. Biotechniques 2015; 59:223-4, 226, 228-9. [PMID: 26458550 DOI: 10.2144/000114341] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/11/2015] [Indexed: 11/23/2022] Open
Abstract
Here we report a simple new method for exposing cells to normoxic and hypoxic conditions using vacuum bags, normally employed for food storage, to establish and maintain low oxygen levels in vitro. Vacuum bags were gassed with a mixture containing specified levels of oxygen, then sealed, creating a hypoxic microenvironment for cells cultured in flasks placed therein. Oxygen levels in the gas mixture and culture medium in flasks inside the sealed bags equilibrated after two hours of incubation. The vacuum bags maintained low oxygen levels (either <2% or 5%) in medium for at least 4 days. Human fetal astrocytes grew normally in flasks for at least 4 days in a 5% oxygen/ 5% CO2/ 90% nitrogen atmosphere, but viability decreased at <2% oxygen. Vacuum bags can accommodate varying oxygen levels that would otherwise require systems with separate chambers or modules, but are less useful when repeated experimental manipulations of individual cultures are required.
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Affiliation(s)
- Supun M Bakmiwewa
- Molecular Immunopathology Unit, Discipline of Pathology, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Benjamin Heng
- The Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Gilles J Guillemin
- The Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Helen J Ball
- Molecular Immunopathology Unit, Discipline of Pathology, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Nicholas H Hunt
- Molecular Immunopathology Unit, Discipline of Pathology, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, Sydney, Australia
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Calzavacca P, Evans RG, Bailey M, Lankadeva YR, Bellomo R, May CN. Long-term measurement of renal cortical and medullary tissue oxygenation and perfusion in unanesthetized sheep. Am J Physiol Regul Integr Comp Physiol 2015; 308:R832-9. [DOI: 10.1152/ajpregu.00515.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/06/2015] [Indexed: 11/22/2022]
Abstract
The role of renal cortical and medullary hypoxia in the development of acute kidney injury is controversial, partly due to a lack of techniques for the long-term measurement of intrarenal oxygenation and perfusion in conscious animals. We have, therefore, developed a methodology to chronically implant combination probes to chronically measure renal cortical and medullary tissue perfusion and oxygen tension (tPo2) in conscious sheep and evaluated their responsiveness and reliability. A transit-time flow probe and a vascular occluder were surgically implanted on the left renal artery. At the same operation, dual fiber-optic probes, comprising a fluorescence optode to measure tPo2 and a laser-Doppler probe to assess tissue perfusion, were inserted into the renal cortex and medulla. In recovered conscious sheep ( n = 8) breathing room air, mean 24-h cortical and medullary tPo2 were similar (31.4 ± 0.6 and 29.7 ± 0.7 mmHg, respectively). In the renal cortex and medulla, a 20% reduction in renal blood flow (RBF) decreased perfusion (14.6 ± 8.6 and 41.2 ± 8.5%, respectively) and oxygenation (48.1 ± 8.5 and 72.4 ± 8.5%, respectively), with greater decreases during a 50% reduction in RBF. At autopsy, minimal fibrosis was observed around the probes. In summary, we have developed a technique to chronically implant fiber-optic probes in the renal cortex and medulla for recording tissue perfusion and oxygenation over many days. In normal resting conscious sheep, cortical and medullary tPo2 were similar. The responses to and recovery from renal artery occlusion, together with the consistent measurements over a 24-h period, demonstrate the responsiveness and stability of the probes.
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Affiliation(s)
- Paolo Calzavacca
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Intensive Care and Department of Medicine, Austin Health, Heidelberg, Victoria, Australia
- Department of Anesthesia and Intensive Care, AO Melegnano, PO Uboldo, Cernusco sul Naviglio, Italy
| | - Roger G. Evans
- Department of Physiology, Monash University, Clayton, Victoria, Australia; and
| | - Michael Bailey
- Australian and New Zealand Intensive Care Research Centre, School of Epidemiology and Preventive Medicine, Monash University, Clayton, Australia
| | - Yugeesh R. Lankadeva
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Rinaldo Bellomo
- Department of Intensive Care and Department of Medicine, Austin Health, Heidelberg, Victoria, Australia
| | - Clive N. May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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Yang R, Zhang Q, Wu Y, Dunn JF. Monitoring angiogenesis using a human compatible calibration for broadband near-infrared spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:16011. [PMID: 23314579 PMCID: PMC3595713 DOI: 10.1117/1.jbo.18.1.016011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 11/06/2012] [Accepted: 12/06/2012] [Indexed: 05/20/2023]
Abstract
Angiogenesis is a hallmark of many conditions, including cancer, stroke, vascular disease, diabetes, and high-altitude exposure. We have previously shown that one can study angiogenesis in animal models by using total hemoglobin (tHb) as a marker of cerebral blood volume (CBV), measured using broadband near-infrared spectroscopy (bNIRS). However, the method was not suitable for patients as global anoxia was used for the calibration. Here we determine if angiogenesis could be detected using a calibration method that could be applied to patients. CBV, as a marker of angiogenesis, is quantified in a rat cortex before and after hypoxia acclimation. Rats are acclimated at 370-mmHg pressure for three weeks, while rats in the control group are housed under the same conditions, but under normal pressure. CBV increased in each animal in the acclimation group. The mean CBV (%volume/volume) is 3.49%± 0.43% (mean ± SD) before acclimation for the experimental group, and 4.76%± 0.29% after acclimation. The CBV for the control group is 3.28%± 0.75%, and 3.09%± 0.48% for the two measurements. This demonstrates that angiogenesis can be monitored noninvasively over time using a bNIRS system with a calibration method that is compatible with human use and less stressful for studies using animals.
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Affiliation(s)
- Runze Yang
- University of Calgary, Department of Radiology, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Qiong Zhang
- University of Calgary, Department of Radiology, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Ying Wu
- University of Calgary, Department of Radiology, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Jeff F. Dunn
- University of Calgary, Department of Radiology, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- University of Calgary, Experimental Imaging Centre, Calgary, Alberta, Canada
- Address all correspondence: Jeff F. Dunn, University of Calgary, Department of Radiology, 3330 Hospital Drive, N.W., Calgary, AB T2N 4N1, Canada. Tel: 403-210-3886; E-mail:
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Cai K, Shore A, Singh A, Haris M, Hiraki T, Waghray P, Reddy D, Greenberg JH, Reddy R. Blood oxygen level dependent angiography (BOLDangio) and its potential applications in cancer research. NMR IN BIOMEDICINE 2012; 25:1125-1132. [PMID: 22302557 PMCID: PMC3390450 DOI: 10.1002/nbm.2780] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/06/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
Clinically, development of anti-angiogenic drugs for cancer therapy is pivotal. Longitudinal monitoring of tumour angiogenesis can help clinicians determine the effectiveness of anti-angiogenic therapy. Blood oxygen level dependent (BOLD) effect has been widely used for functional imaging and tumour oxygenation assessment. In this study, the BOLD effect is investigated under different levels of oxygen inhalation for the development of a novel angiographic MRI technique, blood oxygen level dependent angiography (BOLDangio). Under short-term (<10 min) generalized hypoxia induced by inhalation of 8% oxygen, we measure BOLD contrast as high as 25% from vessels at 9.4T using a simple gradient echo (GRE) pulse sequence. This produces high-resolution 2D and 3D maps of normal and tumour brain vasculature in less than 10 minutes. Additionally, this technique reliably detects metastatic tumours and tumour-induced intracranial hemorrhage. BOLDangio provides a sensitive research tool for MRI of vasculature under normal and pathological conditions. Thus, it may be applied as a simple monitoring technique for measuring the effectiveness of anti-angiogenic drugs in a preclinical environment.
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Affiliation(s)
- Kejia Cai
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
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Dunn JF, Wu Y, Zhao Z, Srinivasan S, Natah SS. Training the brain to survive stroke. PLoS One 2012; 7:e45108. [PMID: 23028788 PMCID: PMC3441606 DOI: 10.1371/journal.pone.0045108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 08/14/2012] [Indexed: 12/20/2022] Open
Abstract
Background Presently, little can be done to repair brain tissue after stroke damage. We hypothesized that the mammalian brain has an intrinsic capacity to adapt to low oxygen which would improve outcome from a reversible hypoxic/ischemic episode. Acclimation to chronic hypoxia causes increased capillarity and tissue oxygen levels which may improve the capacity to survive ischemia. Identification of these adaptations will lead to protocols which high risk groups could use to improve recovery and reduce costs. Methods and Findings Rats were exposed to hypoxia (3 weeks living at ½ an atmosphere). After acclimation, capillary density was measured morphometrically and was increased by 30% in the cortex. Novel implantable oxygen sensors showed that partial pressure of oxygen in the brain was increased by 40% in the normal cortex. Infarcts were induced in brain with 1 h reversible middle cerebral artery occlusions. After ischemia (48 h) behavioural scores were improved and T2 weighted MRI lesion volumes were reduced by 52% in acclimated groups. There was a reduction in inflammation indicated by reduced lymphocytes (by 27–33%), and ED1 positive cells (by 35–45%). Conclusions It is possible to stimulate a natural adaptive mechanism in the brain which will reduce damage and improve outcome for a given ischemic event. Since these adaptations occur after factors such as HIF-1α have returned to baseline, protection is likely related more to morphological changes such as angiogenesis. Such pre-conditioning, perhaps with exercise or pharmaceuticals, would not necessarily reduce the incidence of stroke, but the severity of damage could be reduced by 50%.
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Affiliation(s)
- Jeff F Dunn
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
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Sightings edited by John W. Severinghaus. High Alt Med Biol 2011. [DOI: 10.1089/ham.2011.12103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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