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Zhang W, Feng J, Liu W, Zhang S, Yu X, Liu J, Shan B, Ma L. Investigating Sea-Level Brain Predictors for Acute Mountain Sickness: A Multimodal MRI Study before and after High-Altitude Exposure. AJNR Am J Neuroradiol 2024; 45:809-818. [PMID: 38663991 PMCID: PMC11288600 DOI: 10.3174/ajnr.a8206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/23/2024] [Indexed: 06/09/2024]
Abstract
BACKGROUND AND PURPOSE Acute mountain sickness is a series of brain-centered symptoms that occur when rapidly ascending to high altitude. Predicting acute mountain sickness before high-altitude exposure is crucial for protecting susceptible individuals. The present study aimed to evaluate the feasibility of predicting acute mountain sickness after high-altitude exposure by using multimodal brain MR imaging features measured at sea level. MATERIALS AND METHODS We recruited 45 healthy sea-level residents who flew to the Qinghai-Tibet Plateau (3650 m). We conducted T1-weighted structural MR imaging, resting-state fMRI, and arterial spin-labeling perfusion MR imaging both at sea level and high altitude. Acute mountain sickness was diagnosed for 5 days using Lake Louise Scoring. Logistic regression with Least Absolute Shrinkage and Selection Operator logistic regression was performed for predicting acute mountain sickness using sea-level MR imaging features. We also validated the predictors by using MR images obtained at high altitude. RESULTS The incidence rate of acute mountain sickness was 80.0%. The model achieved an area under the receiver operating characteristic curve of 86.4% (sensitivity = 77.8%, specificity = 100.0%, and P < .001) in predicting acute mountain sickness At sea level, valid predictors included fractional amplitude of low-frequency fluctuations (fALFF) and degree centrality from resting-state fMRI, mainly distributed in the somatomotor network. We further learned that the acute mountain sickness group had lower levels of fALFF in the somatomotor network at high altitude, associated with smaller changes in CSF volume and higher Lake Louise Scoring, specifically relating to fatigue and clinical function. CONCLUSIONS Our study found that the somatomotor network function detected by sea-level resting-state fMRI was a crucial predictor for acute mountain sickness and further validated its pathophysiologic impact at high altitude. These findings show promise for pre-exposure prediction, particularly for individuals in need of rapid ascent, and they offer insight into the potential mechanism of acute mountain sickness.
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Affiliation(s)
- Wei Zhang
- From the Beijing Engineering Research Center of Radiographic Techniques and Equipment (W.Z., B.S.), Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
- School of Nuclear Science and Technology (W.Z., B.S.), University of Chinese Academy of Sciences, Beijing, China
- Cognitive Neuroimaging Centre (W.Z.), Nanyang Technological University, Singapore
- Lee Kong Chian School of Medicine (W.Z.), Nanyang Technological University, Singapore
| | - Jie Feng
- The Graduate School (J.F., X.Y., L.M.), Medical School of Chinese People's Liberation Army, Beijing, China
- Department of Radiology (J.F., W.L., S.Z., X.Y., L.M.), The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
| | - Wenjia Liu
- Department of Radiology (J.F., W.L., S.Z., X.Y., L.M.), The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
| | - Shiyu Zhang
- Department of Radiology (J.F., W.L., S.Z., X.Y., L.M.), The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
- Department of Radiology (S.Z.), Capital Medical University Affiliated Beijing Friendship Hospital, Beijing, China
| | - Xiao Yu
- The Graduate School (J.F., X.Y., L.M.), Medical School of Chinese People's Liberation Army, Beijing, China
- Department of Radiology (J.F., W.L., S.Z., X.Y., L.M.), The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
- Department of Radiology (X.Y.), Beijing Jingmei Group General Hospital, Beijing, China
| | - Jie Liu
- Department of Radiology (J.L.), General Hospital of Tibet Military Region, Tibet, China
| | - Baoci Shan
- From the Beijing Engineering Research Center of Radiographic Techniques and Equipment (W.Z., B.S.), Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
- School of Nuclear Science and Technology (W.Z., B.S.), University of Chinese Academy of Sciences, Beijing, China
| | - Lin Ma
- The Graduate School (J.F., X.Y., L.M.), Medical School of Chinese People's Liberation Army, Beijing, China
- Department of Radiology (J.F., W.L., S.Z., X.Y., L.M.), The First Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
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Liu Y, Yuan F, Peng Z, Zhan Y, Lin J, Zhang R, Zhang J. Decrease in Cerebral Blood Flow after Reoxygenation Is Associated with Neurological Syndrome Sequelae and Blood Pressure. Brain Sci 2023; 13:1600. [PMID: 38002559 PMCID: PMC10669967 DOI: 10.3390/brainsci13111600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Changes in cerebral blood flow (CBF) and regulation of cerebral circulation occur at high altitude (HA). However, the changes in CBF and their associations with neurological syndrome sequelae and blood pressure after subjects return to the lowlands remain unclear. In this study, the subjects were 23 college students who were teaching at an altitude of 4300 m for 30 days. These subjects were studied before reaching the HA (Test 1), one week after returning to the lowlands (Test 2), and three months after returning to the lowlands (Test 3). Symptom scores for de-acclimatization syndrome were evaluated. Changes in CBF were measured using the magnetic resonance imaging arterial spin labeling (ASL) technique. Additionally, the velocity of CBF in the cerebral arteries was measured using a transcranial doppler (TCD). In Test 2 vs. Test 1, the peak systolic velocity and mean velocity in the basilar artery were significantly decreased. CBF exhibited significant decreases in the left putamen/cerebellum crus1/vermis and right thalamus/inferior temporal gyrus, while significant increases were observed in the left postcentral gyrus/precuneus and right middle cingulate gyrus/superior frontal gyrus. In Test 3 vs. Test 1, the basilar artery velocity returned to the baseline level, while CBF continued to decrease. The mean global CBF showed a decreasing trend from Test 1 to Test 3. Furthermore, the mean global CBF had a negative correlation with the systolic pressure, pulse pressure, and mean arterial pressure. The decrease in CBF after reoxygenation may underlie the neurological symptoms in subjects returning to the lowlands. Increased blood pressure could serve as a predictor of a decrease in CBF.
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Affiliation(s)
- Yanqiu Liu
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Fengjuan Yuan
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Zhongwei Peng
- Department of Neurology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361004, China
| | - Yadong Zhan
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Jianzhong Lin
- Department of Radiology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361004, China
| | - Ran Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
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Horiuchi M, Rossetti GM, Oliver SJ. Dietary nitrate supplementation effect on dynamic cerebral autoregulation in normoxia and acute hypoxia. J Cereb Blood Flow Metab 2022; 42:486-494. [PMID: 32151227 PMCID: PMC8985441 DOI: 10.1177/0271678x20910053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We tested the hypothesis that increasing the nitric oxide (NO) bioavailability by dietary nitrate would recover the hypoxia-induced reduction in dynamic cerebral autoregulation (CA). Twelve healthy males (age 21 ± 2 years) completed four days of dietary supplementation with a placebo or inorganic nitrate drink (140-ml beetroot juice per day) followed by 60-min of normoxia or hypoxia (fraction of inspired oxygen [FiO2] = 13%). Duplex ultrasonography was used to perform volumetric change-based assessment of dynamic CA in the internal carotid artery (ICA). Dynamic CA was assessed by rate of regulation (RoR) of vascular conductance using the thigh-cuff method. Four days of beetroot supplementation increased circulating nitrate by 208 [171,245] μM (mean difference [95% confidence interval]) compared with placebo. Dynamic CA was lower in hypoxia than normoxia (RoR Δ-0.085 [-0.116, -0.054]). Compared with placebo, nitrate did not alter dynamic CA in normoxia (RoR Δ-0.022 [-0.060, 0.016]) or hypoxia (RoR Δ0.017 [-0.019, 0.053]). Further, nitrate did not affect ICA vessel diameter, blood velocity or flow in either normoxia or hypoxia. Increased bioavailability of NO through dietary nitrate supplementation did not recover the hypoxia-induced reduction in dynamic CA. This suggests the mechanism of hypoxia-induced reduction in dynamic CA does not relate to the availability of NO.
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Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fujiyoshida, Japan
| | - Gabriella Mk Rossetti
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, Wales
| | - Samuel J Oliver
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, Wales
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Huang H, Dong H, Zhang J, Ke X, Li P, Zhang E, Xu G, Sun B, Gao Y. The Role of Salivary miR-134-3p and miR-15b-5p as Potential Non-invasive Predictors for Not Developing Acute Mountain Sickness. Front Physiol 2019; 10:898. [PMID: 31379603 PMCID: PMC6646415 DOI: 10.3389/fphys.2019.00898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/27/2019] [Indexed: 01/28/2023] Open
Abstract
Background Acute mountain sickness (AMS) is a crucial public health problem for high altitude travelers. Discriminating individuals who are not developing (AMS resistance, AMS−) from developing AMS (AMS susceptibility, AMS+) at baseline would be vital for disease prevention. Salivary microRNAs (miRNAs) have emerged as promising non-invasive biomarkers for various diseases. Thus, the aim of our study was to identify the potential roles of salivary miRNAs in identifying AMS− individuals pre-exposed to high altitude. Moreover, as hypoxia is the triggering factor for AMS, present study also explored the association between cerebral tissue oxygenation indices (TOI) and AMS development after exposed to high altitude, which was the complementary aim. Methods In this study, 124 healthy men were recruited, and were exposed at simulated high altitude of 4,500 m. Salivary miR-134-3p and miR-15b-5p were measured at baseline (200 m). AMS was diagnosed based on Lake Louise Scoring System at 4,500 m. The measurements of physiological parameters were recorded at both the altitudes. Results Salivary miR-134-3p and miR-15b-5p were significantly up-regulated in AMS− individuals as compared to the AMS+ (p < 0.05). In addition, the combination of these miRNAs generated a high power for discriminating the AMS− from AMS+ at baseline (AUC: 0.811, 95% CI: 0.731−0.876, p < 0.001). Moreover, the value of cerebral TOIs at 4,500 m were significantly higher in AMS− individuals, compared to AMS+ (p < 0.01). Conclusion Our study reveals for the first time that salivary miR-134-3p and miR-15b-5p can be used as non-invasive biomarkers for predicting AMS− individuals pre-exposed to high altitude.
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Affiliation(s)
- He Huang
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Huaping Dong
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Jianyang Zhang
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Xianfeng Ke
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Peng Li
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Department of High Altitude Operational Medicine, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Erlong Zhang
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Gang Xu
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Bingda Sun
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Yuqi Gao
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
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Horiuchi M, Endo J, Dobashi S, Kiuchi M, Koyama K, Subudhi AW. Effect of progressive normobaric hypoxia on dynamic cerebral autoregulation. Exp Physiol 2016; 101:1276-1284. [DOI: 10.1113/ep085789] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/12/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science; Mount Fuji Research Institute; Japan
| | - Junko Endo
- Division of Human Environmental Science; Mount Fuji Research Institute; Japan
| | - Shohei Dobashi
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Masataka Kiuchi
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Katsuhiro Koyama
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Andrew W. Subudhi
- Department of Biology; University of Colorado; Colorado Springs CO USA
- Altitude Research Center; University of Colorado Anschutz Medical Campus; Aurora CO USA
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Carl J, Tideman DA, Ravn S, Lund K, Magnisdottir SO, Kjærgaard B. Intravenous Infusion of Nitroglycerine Leads to Increased Permeability on Dynamic Contrast-Enhanced MR Imaging in Pig Brains. AJNR Am J Neuroradiol 2015; 36:1288-92. [PMID: 25814659 DOI: 10.3174/ajnr.a4279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/02/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE It has been suggested that off-label use of transdermal nitroglycerine patches to prevent frostbite may lead to severe acute mountain sickness and ataxia. The aim of this study was to investigate the effect of nitroglycerine on brain vascular permeability by using dynamic contrast-enhanced MR imaging in a swine model. MATERIALS AND METHODS Eight Danish Landrace-Yorkshire-Danish Landrace pigs of approximately 20-25 kg were scanned with a dynamic contrast-enhanced MR perfusion protocol with and without nitroglycerine intravenous infusion. Compartmental analysis was performed on the basis of the Tofts model, and voxel-based quantitative values of the volume transfer constants from the vascular to the extracellular space were determined. RESULTS The scan with nitroglycerine infusion resulted in significantly higher volume transfer constant values than values derived from the first scan without nitroglycerine infusion. Increased volume transfer constant values were observed in 6 of 8 animals. CONCLUSIONS Infusion of nitroglycerine increases the vascular permeability of the swine brain on the basis of the transfer constant estimated from dynamic contrast-enhanced MR imaging.
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Affiliation(s)
- J Carl
- From the Department of Medical Physics, Oncology (J.C., D.A.T., S.R., K.L.)
| | - D A Tideman
- From the Department of Medical Physics, Oncology (J.C., D.A.T., S.R., K.L.)
| | - S Ravn
- From the Department of Medical Physics, Oncology (J.C., D.A.T., S.R., K.L.)
| | - K Lund
- From the Department of Medical Physics, Oncology (J.C., D.A.T., S.R., K.L.)
| | - S O Magnisdottir
- Biomedical Research Laboratory (S.O.M., B.K.), Aalborg University Hospital, Aalborg, Denmark
| | - B Kjærgaard
- Biomedical Research Laboratory (S.O.M., B.K.), Aalborg University Hospital, Aalborg, Denmark
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Subudhi AW, Grajzel K, Langolf RJ, Roach RC, Panerai RB, Davis JE. Cerebral autoregulation index at high altitude assessed by thigh-cuff and transfer function analysis techniques. Exp Physiol 2015; 100:173-81. [DOI: 10.1113/expphysiol.2014.082479] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/27/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Andrew W. Subudhi
- Department of Biology; University of Colorado Colorado Springs; Colorado Springs CO USA
- Department of Emergency Medicine; University of Colorado Altitude Research Center; Aurora CO USA
| | - Katalin Grajzel
- Department of Psychology; University of Colorado Colorado Springs; Colorado Springs CO USA
| | - Robert J. Langolf
- Alma College; Department of Integrative Physiology and Health Science; Alma MI USA
| | - Robert C. Roach
- Department of Emergency Medicine; University of Colorado Altitude Research Center; Aurora CO USA
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences and NIHR Biomedical Research Unit; University of Leicester; UK
| | - John E. Davis
- Alma College; Department of Integrative Physiology and Health Science; Alma MI USA
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9
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Carod-Artal F. Cefalea de elevada altitud y mal de altura. Neurologia 2014; 29:533-40. [DOI: 10.1016/j.nrl.2012.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/21/2012] [Indexed: 11/29/2022] Open
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10
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Subudhi AW, Fan JL, Evero O, Bourdillon N, Kayser B, Julian CG, Lovering AT, Panerai RB, Roach RC. AltitudeOmics: cerebral autoregulation during ascent, acclimatization, and re-exposure to high altitude and its relation with acute mountain sickness. J Appl Physiol (1985) 2014; 116:724-9. [DOI: 10.1152/japplphysiol.00880.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cerebral autoregulation (CA) acts to maintain brain blood flow despite fluctuations in perfusion pressure. Acute hypoxia is thought to impair CA, but it is unclear if CA is affected by acclimatization or related to the development of acute mountain sickness (AMS). We assessed changes in CA using transfer function analysis of spontaneous fluctuations in radial artery blood pressure (indwelling catheter) and resulting changes in middle cerebral artery blood flow velocity (transcranial Doppler) in 21 active individuals at sea level upon arrival at 5,260 m (ALT1), after 16 days of acclimatization (ALT16), and upon re-exposure to 5,260 m after 7 days at 1,525 m (POST7). The Lake Louise Questionnaire was used to evaluate AMS symptom severity. CA was impaired upon arrival at ALT1 ( P < 0.001) and did not change with acclimatization at ALT16 or upon re-exposure at POST7. CA was not associated with AMS symptoms (all R < 0.50, P > 0.05). These findings suggest that alterations in CA are an intrinsic consequence of hypoxia and are not directly related to the occurrence or severity of AMS.
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Affiliation(s)
- Andrew W. Subudhi
- University of Colorado Altitude Research Center, Department of Emergency Medicine, Anschutz Medical Campus, Aurora, Colorado
- University of Colorado Colorado Springs, Department of Biology, Colorado Springs, Colorado
| | - Jui-Lin Fan
- University of Lausanne, Institute of Sports Sciences, Lausanne, Switzerland
- University of Geneva, Lemanic Doctoral School of Neuroscience, Geneva, Switzerland
| | - Oghenero Evero
- University of Colorado Altitude Research Center, Department of Emergency Medicine, Anschutz Medical Campus, Aurora, Colorado
| | - Nicolas Bourdillon
- University of Lausanne, Institute of Sports Sciences, Lausanne, Switzerland
| | - Bengt Kayser
- University of Lausanne, Institute of Sports Sciences, Lausanne, Switzerland
| | - Colleen G. Julian
- University of Colorado Altitude Research Center, Department of Emergency Medicine, Anschutz Medical Campus, Aurora, Colorado
| | - Andrew T. Lovering
- University of Oregon, Department of Human Physiology, Eugene, Oregon; and
| | - Ronney B. Panerai
- University of Leicester, Leicester Royal Infirmary, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Robert C. Roach
- University of Colorado Altitude Research Center, Department of Emergency Medicine, Anschutz Medical Campus, Aurora, Colorado
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Smirl JD, Lucas SJE, Lewis NCS, duManoir GR, Smith KJ, Bakker A, Basnyat AS, Ainslie PN, Ainslie PN. Cerebral pressure-flow relationship in lowlanders and natives at high altitude. J Cereb Blood Flow Metab 2014; 34:248-57. [PMID: 24169852 PMCID: PMC3915197 DOI: 10.1038/jcbfm.2013.178] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 08/13/2013] [Accepted: 09/09/2013] [Indexed: 12/30/2022]
Abstract
We investigated if dynamic cerebral pressure-flow relationships in lowlanders are altered at high altitude (HA), differ in HA natives and after return to sea level (SL). Lowlanders were tested at SL (n=16), arrival to 5,050 m, after 2-week acclimatization (with and without end-tidal PO2 normalization), and upon SL return. High-altitude natives (n=16) were tested at 5,050 m. Testing sessions involved resting spontaneous and driven (squat-stand maneuvers at very low (VLF, 0.05 Hz) and low (LF, 0.10 Hz) frequencies) measures to maximize blood pressure (BP) variability and improve assessment of the pressure-flow relationship using transfer function analysis (TFA). Blood flow velocity was assessed in the middle (MCAv) and posterior (PCAv) cerebral arteries. Spontaneous VLF and LF phases were reduced and coherence was elevated with acclimatization to HA (P<0.05), indicating impaired pressure-flow coupling. However, when BP was driven, both the frequency- and time-domain metrics were unaltered and comparable with HA natives. Acute mountain sickness was unrelated to TFA metrics. In conclusion, the driven cerebral pressure-flow relationship (in both frequency and time domains) is unaltered at 5,050 m in lowlanders and HA natives. Our findings indicate that spontaneous changes in TFA metrics do not necessarily reflect physiologically important alterations in the capacity of the brain to regulate BP.
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Affiliation(s)
- Jonathan D Smirl
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Samuel J E Lucas
- 1] Department of Physiology, University of Otago, Dunedin, New Zealand [2] School of Physical Education, University of Otago, Dunedin, New Zealand [3] School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Nia C S Lewis
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | | | - Kurt J Smith
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Akke Bakker
- University of Twente, Enschede, The Netherlands
| | | | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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12
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Zafren K. Prevention of high altitude illness. Travel Med Infect Dis 2014; 12:29-39. [DOI: 10.1016/j.tmaid.2013.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/05/2013] [Accepted: 12/10/2013] [Indexed: 11/28/2022]
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13
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Sightings edited by John W. Severinghaus. High Alt Med Biol 2012. [DOI: 10.1089/ham.2012.1312] [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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