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Han C, Zheng XX, Zhang WF. High altitude retinopathy: An overview and new insights. Travel Med Infect Dis 2024; 58:102689. [PMID: 38295966 DOI: 10.1016/j.tmaid.2024.102689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/30/2023] [Accepted: 01/15/2024] [Indexed: 02/04/2024]
Abstract
High altitude retinopathy (HAR) is a common ocular disorder that occurs on ascent to high altitude. There are many clinical symptoms, retinal vascular dilatation, retinal edema and hemorrhage are common. These usually do not or slightly affect vision; rarely, severe cases develop serious or permanent vision loss. At present, the research progress of HAR mainly focuses on hemodynamic changes, blood-retinal barrier damage, oxidative stress and inflammatory response. Although the related studies on HAR are limited, it shows that HAR still belongs to hypoxia, and hypobaric hypoxia plays an aggravating role in promoting the development of the disease. Various studies have demonstrated the correlation of HAR with acute mountain sickness (AMS) and high-altitude cerebral edema (HACE), so a deeper understanding of HAR is important. The slow ascent rates and ascent altitude are the key to preventing any altitude sickness. Research on traditional chinese medicine (TCM) and western medicine has been gradually carried out. Further exploration of the pathogenesis and prevention strategies of HAR will provide better guidance for doctors and high-altitude travelers.
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Affiliation(s)
- Cong Han
- Department of Ophthalmology, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, 730000, Gansu, PR China.
| | - Xing-Xing Zheng
- Department of Ophthalmology, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, 730000, Gansu, PR China.
| | - Wen-Fang Zhang
- Department of Ophthalmology, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, 730000, Gansu, PR China.
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Westwood J, Mayhook-Walker I, Simpkins C, Darby-Smith A, Morris D, Normando E. Retinal Vascular Changes in Response to Hypoxia: A High-Altitude Expedition Study. High Alt Med Biol 2024; 25:49-59. [PMID: 38011631 DOI: 10.1089/ham.2023.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Westwood, Jessica, India Mayhook-Walker, Ciaran Simpkins, Andrew Darby-Smith, Dan Morris, and Eduardo Normando. Retinal vascular changes in response to hypoxia: a high-altitude expedition study. High Alt Med Biol. 25:49-59, 2024. Background: Increased tortuosity and engorgement of retinal vasculature are recognized physiological responses to hypoxia. This can lead to high-altitude retinopathy (HAR), but incidence reports are highly variable, and our understanding of the etiological mechanisms remains incomplete. This study quantitatively evaluated retinal vascular changes during an expedition to 4,167 m. Methods: Ten healthy participants summited Mount Toubkal, Morocco. Fundus images were taken predeparture, daily throughout the expedition, and 1 month postreturn. Diameter and tortuosity of four vessels were assessed, in addition to vessel density and features of HAR. Results: Significant (p ≤ 0.05) increases in tortuosity and diameter were observed in several vessels on high-altitude exposure days. There was a strong correlation between altitude and supratemporal retinal artery diameter on days 2, 3, and 6 of the expedition (r = 0.7707, 0.7951, 0.7401, respectively; p < 0.05). There was a significant increase in median vessel density from 6.7% at baseline to 10.0% on summit day. Notably there were no incidences of HAR. Conclusion: Physiological but not pathological changes were seen in this cohort, which gives insight into the state of the cerebral vasculature throughout this expedition. These results are likely attributable to relatively low altitude exposure, a conservative ascent profile, and the cohort's demographic. Future study must include daily retinal images at higher altitudes and take steps to mitigate environmental confounders. This study is relevant to altitude tourists, patients with diabetic retinopathy or retinal vein occlusion, and critically ill patients.
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Affiliation(s)
- Jessica Westwood
- Imperial College London Ophthalmology Research Group, Western Eye Hospital, London, United Kingdom
| | - India Mayhook-Walker
- Imperial College London Ophthalmology Research Group, Western Eye Hospital, London, United Kingdom
| | - Ciaran Simpkins
- Imperial College London Ophthalmology Research Group, Western Eye Hospital, London, United Kingdom
| | - Andrew Darby-Smith
- Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Dan Morris
- Cardiff Eye Unit, University Hospital of Wales, Cardiff, United Kingdom
| | - Eduardo Normando
- Imperial College London Ophthalmology Research Group, Western Eye Hospital, London, United Kingdom
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Kumar S, Mondal S, Kumar R. Unusual Case Report of Headache in 10-Year-Old Female Child. Cureus 2024; 16:e53590. [PMID: 38449939 PMCID: PMC10915452 DOI: 10.7759/cureus.53590] [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] [Accepted: 02/04/2024] [Indexed: 03/08/2024] Open
Abstract
According to the literature, transverse sinus hypoplasia is not a normal variant and has a serious potential effect on cerebral blood flow. We are presenting a rare case of chronic headache due to severe hypoplasia of the left transverse and sigmoidal sinus. A 12-year-old female girl was admitted with a complaint of gradual progressive severe headache, throbbing in nature, confined to a bitemporal and frontal region in the last 4-5 months. Headache is not associated with fever, vomiting, photophobia, or vision problems. The child had no history of recurrent running nose, refractory vision, ear discharge, head trauma, exanthemata rash, or any drug history. On examination, the child was conscious and oriented. Vital signs are normal. The child was neurologically normal and had no focal signs. Other systemic examinations were normal. Based on History and examination, differential diagnosis was made, like Pseudo tumor cerebri, migraine, deep vein sinus thrombosis, and functional and Posterior fossa tumor. The child had normal routine investigations like complete blood count, electrolyte, and D-dimer. The fundoscopy was normal. In MRI, brain hypoplasia of the left transverse and sinusoidal sinus was suspected and confirmed by MRI venography. Thus, for any patient in an emergency with a chronic headache without focal signs and normal fundoscopy, one deferential should be considered for transverse and sigmoid sinus hypoplasia.
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Affiliation(s)
- Sudesh Kumar
- Pediatrics, Mata Gujri Memorial Medical College, Kishanganj, IND
| | | | - Roshan Kumar
- Medicine, Mata Gujri Memorial Medical College, Kishanganj, IND
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Retinal microvasculature is a potential biomarker for acute mountain sickness. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2271-x. [PMID: 36811802 DOI: 10.1007/s11427-022-2271-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/21/2022] [Indexed: 02/24/2023]
Abstract
Increased cerebral blood flow resulting from altered capillary level autoregulation at high altitudes leads to capillary overperfusion and then vasogenic cerebral edema, which is the leading hypothesis of acute mountain sickness (AMS). However, studies on cerebral blood flow in AMS have been mostly restricted to gross cerebrovascular endpoints as opposed to the microvasculature. This study aimed to investigate ocular microcirculation alterations, the only visualized capillaries in the central neural system (CNS), during early-stage AMS using a hypobaric chamber. This study found that after high altitude simulation, the optic nerve showed retinal nerve fiber layer thickening (P=0.004-0.018) in some locations, and the area of the optic nerve subarachnoid space (P=0.004) enlarged. Optical coherence tomography angiography (OCTA) showed increased retinal radial peripapillary capillary (RPC) flow density (P=0.003-0.046), particularly on the nasal side of the nerve. The AMS-positive group had the largest increases in RPC flow density in the nasal sector (AMS-positive, Δ3.21±2.37; AMS-negative, Δ0.01±2.16, P=0.004). Among multiple ocular changes, OCTA increase in RPC flow density was associated with simulated early-stage AMS symptoms (beta=0.222, 95%CI, 0.009-0.435, P=0.042). The area under the receiver operating characteristics curve (AUC) for the changes in RPC flow density to predict early-stage AMS outcomes was 0.882 (95%CI, 0.746-0.998). The results further confirmed that overperfusion of microvascular beds is the key pathophysiologic change in early-stage AMS. RPC OCTA endpoints may serve as a rapid, noninvasive potential biomarker for CNS microvascular changes and AMS development during risk assessment of individuals at high altitudes.
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Ma J, Niu H, Han C, Qu Y. Quantify retinal structure in high-altitude residents with and without high altitude polycythemia. BMC Ophthalmol 2023; 23:6. [PMID: 36597056 PMCID: PMC9811807 DOI: 10.1186/s12886-022-02674-7] [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: 05/17/2022] [Accepted: 11/07/2022] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND To assess retinal structural parameters in high-altitude (HA) residents with and without high altitude polycythemia (HAPC) and to elucidate the relationship between retinal structural parameters and hemoglobin (HGB). METHODS This cross-sectional study included 55 HAPC patients and 52 healthy HA residents. Retinal structural parameters included retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) parameters and retinal vessel diameter. RNFL thickness were acquired from spectral domain optical coherence tomography (SD-OCT) built-in software. ONH parameters including neuroretina rim height, cup area, disc area and vertical cup/disc ratio were obtained by OCT built-in software and ImageJ software. Retinal vessel measurements including central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE) and AVR (artery/vein ratio) were calculated by revised formulas for summarizing retinal vessel diameters. All parameters were compared between HAPC group versus healthy HA group. The associations between retinal parameters and HGB were assessed by Pearson correlation analyses. RESULTS In comparison of HAPC group versus healthy HA group, RNFL thickness was thicker in the nasal quadrant of the optic disc in HAPC group (74.82 ± 14.4 VS. 66.06 ± 13.71 μm, P = 0.002). Bigger disc area and bigger cup area were also observed in HAPC group (all P < 0.05). Meanwhile, the value of CRVE was higher in HAPC group which suggested that retinal veins dilated significantly in HAPC patients (P < 0.001), however, CRAE and AVR were comparable between groups. Pearson analyses revealed that HGB was positive correlated with CRVE in HAPC group (r = 0.469, P = 0.003). CONCLUSIONS long-term HA exposure secondary HAPC could result in thickened RNFL, enlarged ONH and dilated retinal veins. Moreover, increased blood viscosity caused by HGB should be responsible for dilated veins, but not for thickened RNFL and enlarged ONH. This study deepens the understanding of the impact of HA environment on retina.
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Affiliation(s)
- Jinlan Ma
- Department of Ophthalmology, Affiliated Hospital of Qinghai University, Xining, China.,Department of Health Care, Qilu Hospital of Shandong University, No. 107, Wenhuaxi Road, Jinan, 250012, China
| | - Haoyu Niu
- Department of Ophthalmology, Affiliated Hospital of Qinghai University, Xining, China
| | - Changjing Han
- Department of Ophthalmology, Affiliated Hospital of Qinghai University, Xining, China
| | - Yi Qu
- Department of Health Care, Qilu Hospital of Shandong University, No. 107, Wenhuaxi Road, Jinan, 250012, China.
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Mlinar T, Debevec T, Kapus J, Najdenov P, McDonnell AC, Ušaj A, Mekjavic IB, Jaki Mekjavic P. Retinal blood vessel diameters in children and adults exposed to a simulated altitude of 3,000 m. Front Physiol 2023; 14:1026987. [PMID: 36926190 PMCID: PMC10011172 DOI: 10.3389/fphys.2023.1026987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 02/14/2023] [Indexed: 03/08/2023] Open
Abstract
Introduction: Technological advances have made high-altitude ski slopes easily accessible to skiers of all ages. However, research on the effects of hypoxia experienced during excursions to such altitudes on physiological systems, including the ocular system, in children is scarce. Retinal vessels are embryologically of the same origin as vessels in the brain, and have similar anatomical and physiological characteristics. Thus, any hypoxia-related changes in the morphology of the former may reflect the status of the latter. Objective: To compare the effect of one-day hypoxic exposure, equivalent to the elevation of high-altitude ski resorts in North America and Europe (∼3,000 m), on retinal vessel diameter between adults and children. Methods: 11 adults (age: 40.1 ± 4.1 years) and 8 children (age: 9.3 ± 1.3 years) took part in the study. They spent 3 days at the Olympic Sports Centre Planica (Slovenia; altitude: 940 m). During days 1 and 2 they were exposed to normoxia (FiO2 = 0.209), and day 3 to normobaric hypoxia (FiO2 = 0.162 ± 0.03). Digital high-resolution retinal fundus photographs were obtained in normoxia (Day 2) and hypoxia (Day 3). Central retinal arteriolar equivalent (CRAE) and venular equivalents (CRVE) were determined using an Automated Retinal Image Analyser. Results: Central retinal arteriolar and venular equivalents increased with hypoxia in children (central retinal arteriolar equivalent: 105.32 ± 7.72 µm, hypoxia: 110.13 ± 7.16 µm, central retinal venular equivalent: normoxia: 123.39 ± 8.34 µm, hypoxia: 130.11 ± 8.54 µm) and adults (central retinal arteriolar equivalent: normoxia: 105.35 ± 10.67 µm, hypoxia: 110.77 ± 8.36 µm; central retinal venular equivalent: normoxia: 126.89 ± 7.24 µm, hypoxia: 132.03 ± 9.72 µm), with no main effect of group or group*condition interaction. A main effect of condition on central retinal arteriolar and venular equivalents was observed (central retinal arteriolar equivalent:normoxia: 105.34 ± 9.30 µm, hypoxia: 110.50 ± 7.67 µm, p < 0.001; central retinal venular equivalent: normoxia: 125.41 ± 7.70 µm, hypoxia: 131.22 ± 9.05 µm, p < 0.001). Conclusion: A 20-hour hypoxic exposure significantly increased central retinal arteriolar and venular equivalents in adults and children. These hypoxia-induced increases were not significantly different between the age groups, confirming that vasomotor sensitivity of the retinal vessels to acute hypoxia is comparable between adults and prepubertal children.
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Affiliation(s)
- Tinkara Mlinar
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Jozef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Tadej Debevec
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Kapus
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Najdenov
- Department of Paediatrics, General Hospital Jesenice, Jesenice, Slovenia
| | - Adam C McDonnell
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Anton Ušaj
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Igor B Mekjavic
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Polona Jaki Mekjavic
- Department of Automatics, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,Eye Hospital, University Medical Centre, Ljubljana, Slovenia.,Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Hou J, Wen X, Long P, Xiong S, Liu H, Cai L, Deng H, Zhang Z. The role of post-translational modifications in driving abnormal cardiovascular complications at high altitude. Front Cardiovasc Med 2022; 9:886300. [PMID: 36186970 PMCID: PMC9515308 DOI: 10.3389/fcvm.2022.886300] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
The high-altitude environment is characterized by hypobaric hypoxia, low temperatures, low humidity, and high radiation, which is a natural challenge for lowland residents entering. Previous studies have confirmed the acute and chronic effects of high altitude on the cardiovascular systems of lowlanders. Abnormal cardiovascular complications, including pulmonary edema, cardiac hypertrophy and pulmonary arterial hypertension were commonly explored. Effective evaluation of cardiovascular adaptive response in high altitude can provide a basis for early warning, prevention, diagnosis, and treatment of altitude diseases. At present, post-translational modifications (PTMs) of proteins are a key step to regulate their biological functions and dynamic interactions with other molecules. This process is regulated by countless enzymes called “writer, reader, and eraser,” and the performance is precisely controlled. Mutations and abnormal expression of these enzymes or their substrates have been implicated in the pathogenesis of cardiovascular diseases associated with high altitude. Although PTMs play an important regulatory role in key processes such as oxidative stress, apoptosis, proliferation, and hypoxia response, little attention has been paid to abnormal cardiovascular response at high altitude. Here, we reviewed the roles of PTMs in driving abnormal cardiovascular complications at high altitude.
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Affiliation(s)
- Jun Hou
- Department of Cardiology, Chengdu Third People’s Hospital, Cardiovascular Disease Research Institute of Chengdu, Affiliated Hospital of Southwest Jiaotong University, Chengdu, China
- School of Material Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Xudong Wen
- Department of Gastroenterology and Hepatology, Chengdu First People’s Hospital, Chengdu, China
| | - Pan Long
- School of Material Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Shiqiang Xiong
- Department of Cardiology, Chengdu Third People’s Hospital, Cardiovascular Disease Research Institute of Chengdu, Affiliated Hospital of Southwest Jiaotong University, Chengdu, China
| | - Hanxiong Liu
- Department of Cardiology, Chengdu Third People’s Hospital, Cardiovascular Disease Research Institute of Chengdu, Affiliated Hospital of Southwest Jiaotong University, Chengdu, China
| | - Lin Cai
- Department of Cardiology, Chengdu Third People’s Hospital, Cardiovascular Disease Research Institute of Chengdu, Affiliated Hospital of Southwest Jiaotong University, Chengdu, China
- *Correspondence: Lin Cai,
| | - Haoyu Deng
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Center for Heart and Lung Innovation, St. Paul’s Hospital, University of British Columbia, Vancouver, BC, Canada
- Department of Vascular Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Haoyu Deng,
| | - Zhen Zhang
- Department of Cardiology, Chengdu Third People’s Hospital, Cardiovascular Disease Research Institute of Chengdu, Affiliated Hospital of Southwest Jiaotong University, Chengdu, China
- Zhen Zhang,
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Chen Z, Ding J, Wu X, Cao X, Liu H, Yin X, Ding Y, Ji X, Meng R. Anatomic Asymmetry of Transverse Sinus May Be Irrelevant to the Prognosis of Intracerebral Hemorrhage. Neurologist 2022; 27:235-239. [PMID: 34873112 PMCID: PMC9439688 DOI: 10.1097/nrl.0000000000000396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND We investigate the probable effect of anatomic asymmetry of transverse sinus (TS) on the outcomes of acute intracerebral hemorrhage (ICH), to provide reference for customized treatment. METHODS Consecutive patients with imaging-confirmed acute ICH were enrolled from October 2015 through October 2019, and divided into 2 groups: symmetrical and unilateral (left or right) slender TS groups, based on the status of TS in imaging maps. Brain computed tomography (CT) maps of all patients at baseline and half-month post-ICH were obtained, and the volumes of hematoma and the perihematomal edemas (PHE), as well as the modified Rankin Scale (mRS) scores at the month-3 post-ICH between the 2 groups were assessed and analyzed. RESULTS A total of 46 eligible patients entered into final analysis, including 18 cases in the slender TS group (14 cases involved the left side while 4 cases involved the right side), and 28 cases in the symmetrical TS group. The mRS scores, hematoma absorption rates, and the residual volumes of PHE of all patients in the 2 groups at half-month post-ICH showed no statistical significance (all P >0.05), and all of the items mentioned above were related to the hematoma volume at baseline (all P <0.001). At the month-3 follow-up post-ICH, the mRS scores between the 2 groups showed no statistical significance as well ( P =0.551). CONCLUSIONS Anatomic asymmetry of TS may not affect the prognosis of PHE and clinical outcome after ICH.
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Affiliation(s)
- Zhiying Chen
- Department of Neurology, Xuanwu Hospital, Capital Medical University
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiangxi
| | - Jiayue Ding
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiaoqin Wu
- Department of Neurology, Xuanwu Hospital, Capital Medical University
| | - Xianming Cao
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiangxi
| | - Hao Liu
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiangxi
| | - Xiaoping Yin
- Department of Neurology, Affiliated Hospital of Jiujiang University, Jiangxi
| | - Yuchuan Ding
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI
| | - Xunming Ji
- Department of Neurology, Xuanwu Hospital, Capital Medical University
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing
| | - Ran Meng
- Department of Neurology, Xuanwu Hospital, Capital Medical University
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing
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Hou J, Zheng D, Wen X, Xiao W, Han F, Lang H, Xiong S, Jiang W, Hu Y, He M, Long P. Proteomic and Morphological Profiling of Mice Ocular Tissue During High-altitude Acclimatization Process: An Animal Study at Lhasa. J Inflamm Res 2022; 15:2835-2853. [PMID: 35645575 PMCID: PMC9135145 DOI: 10.2147/jir.s361174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/27/2022] [Indexed: 12/31/2022] Open
Abstract
Purpose High-altitude environment mainly with hypobaric hypoxia could induce pathological alterations in ocular tissue. Previous studies have mostly focused on sporadic case reports and simulated high-altitude hypoxia experiments. This aim of this study was to explore the proteomic and morphological changes of ocular tissue in mice at real altitude environment. Methods In this study, mice were flown from Chengdu (elevation: 500 m) to Lhasa (elevation: 3600 m). After exposure for 1day, 3, 6, 10, 20, 30, and 40days, the mice were euthanatized to obtain blood and ocular tissue. Serological tests, ocular pathological examinations, integral ocular proteomics analysis, and Western blot were conducted. Results We focused on acute phase (1–3 days) and chronic phase (>30 days) during high-altitude acclimatization. Serum interleukin-1 was increased at 3 days, while superoxide dismutase, interleukin-6, and tumor necrosis factor-α showed no statistical changes. H&E staining demonstrated that the cornea was edematous at 3 days and exhibited slower proliferation at 30 days. The choroid showed a consistently significant thickening, while there existed no noticeable changes in retinal thickness. Overall, 4073 proteins were identified, among which 71 and 119 proteins were detected to have significant difference at 3 days and 40 days when compared with the control group. Functional enrichment analysis found the differentiated proteins at 3 days exposure functionally related with response to radiation, dephosphorylation, negative regulation of cell adhesion, and erythrocyte homeostasis. Moreover, the differential profiles of the proteins at 40 days exposure exhibited changes of regulation of complement activation, regulation of protein activation cascade, regulation of humoral immune response, second-messenger-mediated signaling, regulation of leukocyte activation, and cellular iron homeostasis. Interestingly, we found the ocular proteins with lactylation modification were increased along high-altitude adaptation. Conclusion This is the first work reporting the ocular proteomic and morphological changes at real high-altitude environment. We expect it would deep the understanding of ocular response during altitude acclimatization.
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Affiliation(s)
- Jun Hou
- Department of Cardiology, Chengdu Third People’s Hospital/Affiliated Hospital of Southwest Jiaotong University, Chengdu, People’s Republic of China
| | - Dezhi Zheng
- Department of Cardiovascular Surgery, the 960th Hospital of the PLA Joint Logistic Support Force, Jinan, People’s Republic of China
| | - Xudong Wen
- Department of Gastroenterology and Hepatology, Chengdu First People’s Hospital, Chengdu, People’s Republic of China
| | - Wenjing Xiao
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, People’s Republic of China
| | - Fei Han
- Department of Ophthalmology, the General Hospital of Western Theater Command, Chengdu, People’s Republic of China
| | - Hongmei Lang
- The Center of Obesity and Metabolic Diseases, Department of General Surgery, Chengdu Third People’s Hospital & the Affiliated Hospital of Southwest Jiaotong University, Chengdu, People’s Republic of China
| | - Shiqiang Xiong
- Department of Cardiology, Chengdu Third People’s Hospital/Affiliated Hospital of Southwest Jiaotong University, Chengdu, People’s Republic of China
| | - Wei Jiang
- Department of Ophthalmology, the General Hospital of Western Theater Command, Chengdu, People’s Republic of China
| | - Yonghe Hu
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, People’s Republic of China
- Yonghe Hu, School of Materials Science and Engineering, Southwest Jiaotong University, No. 111, North First Section of the Second Ring Road, Chengdu, People’s Republic of China, Tel +86-138-8059-6789, Email
| | - Mengshan He
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Pan Long
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, People’s Republic of China
- Department of Ophthalmology, the General Hospital of Western Theater Command, Chengdu, People’s Republic of China
- Correspondence: Pan Long, Department of Ophthalmology, the General Hospital of Western Theater Command, Rongdu Avenue #270, Chengdu, People’s Republic of China, Tel +86-181-9125-6132, Email
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The assessment of headache and sleep quality in patients with chronic obstructive pulmonary disease. JOURNAL OF SURGERY AND MEDICINE 2022. [DOI: 10.28982/josam.983605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Song K, Zeng X, Xie X, Zhu R, Liang J, Chen G, Huang L. Dl-3-n-butylphthalide attenuates brain injury caused by cortical infarction accompanied by cranial venous drainage disturbance. Stroke Vasc Neurol 2022; 7:222-236. [PMID: 35101948 PMCID: PMC9240610 DOI: 10.1136/svn-2021-001308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/14/2021] [Indexed: 11/04/2022] Open
Abstract
Background Cerebral venous disorder may have a harmful effect on ischaemic stroke; however, the underlying mechanism remains to be elucidated. Although Dl-3-n-butylphthalide is a multitarget agent for antiischaemic stroke, its neuroprotective role in brain ischaemia accompanied by brain venous disturbance remains unclear. In this study, we induced cerebral venous disturbance by the occlusion of bilateral external jugular veins (EJVs) to explore the potential mechanism of the adverse effects of cerebrovenous disorders in cerebral infarction and explore the protective effect of Dl-3-n-butylphthalide on cerebral infarction accompanied through cerebral venous disturbance. Methods Cerebral venous disturbance was induced in Sprague-Dawley rats through the permanent occlusion of bilateral EJVs, and cerebral ischaemic stroke was induced through the permanent occlusion of the right cortical branches of the middle cerebral artery. 2,3,5-triphenyltetrazolium chloride staining, MRI, Evans blue extravasation and behavioural test were performed to evaluate infarction volume, cerebral blood flow (CBF), blood–brain barrier (BBB) integrity and neurological function. Immunofluorescence staining and western blot analysis were performed to detect loss of neuron, endothelial cells, pericytes and tight junctions. Results Bilateral EJVs occlusion did not cause cerebral infarction; however, it increased the infarction volume compared with the simple middle cerebral artery occlusion (MCAO) group, accompanied by severe neuron loss, worse neurological function, lower CBF, increased EJVs pressure, exacerbated Evans blue extravasation and brain oedema, as well as attenuated angiogenesis. Dl-3-n-butylphthalide displayed a neuroprotective effect in rats with MCAO accompanied by EJVs occlusion by reducing neuron loss, accelerating CBF restoration, promoting angiogenesis and relieving BBB damage. Conclusion Bilateral EJVs occlusion did not significantly affect normal rats but aggravated brain damage in the case of ischaemic stroke. Dl-3-n-butylphthalide treatment plays a neuroprotective role in rats with MCAO accompanied by EJVs occlusion, mainly due to the promotion of CBF restoration and BBB protection.
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Affiliation(s)
- Kangping Song
- Department of Neurology, Jinan University First Affiliated Hospital, Guangzhou, China
| | - Xiuli Zeng
- Department of Neurology, Jinan University First Affiliated Hospital, Guangzhou, China
| | - Xiaomei Xie
- Department of Neurology, Jinan University First Affiliated Hospital, Guangzhou, China
| | - Rongxuan Zhu
- Department of Neurology, Jinan University First Affiliated Hospital, Guangzhou, China
| | - Jianye Liang
- Medical Imaging Center, Jinan University First Affiliated Hospital, Guangzhou, China
| | - Guobing Chen
- Institute of Geriatric Immunology, Medical college of Jinan University, Guangzhou, China
| | - Li'an Huang
- Department of Neurology, Jinan University First Affiliated Hospital, Guangzhou, China
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12
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Ogoh S, Washio T, Stacey BS, Tsukamoto H, Iannetelli A, Owens TS, Calverley TA, Fall L, Marley CJ, Saito S, Watanabe H, Hashimoto T, Ando S, Miyamoto T, Bailey DM. Integrated respiratory chemoreflex-mediated regulation of cerebral blood flow in hypoxia: Implications for oxygen delivery and acute mountain sickness. Exp Physiol 2021; 106:1922-1938. [PMID: 34318560 DOI: 10.1113/ep089660] [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] [Received: 04/12/2021] [Accepted: 07/20/2021] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? To what extent do hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral oxygen delivery, with corresponding implications for susceptibility to acute mountain sickness? What is the main finding and its importance? We provide evidence for site-specific regulation of cerebral blood flow in hypoxia that preserves oxygen delivery in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. External carotid artery vasodilatation might prove to be an alternative haemodynamic risk factor that predisposes to acute mountain sickness. ABSTRACT The aim of the present study was to determine the extent to which hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral blood flow (CBF) and oxygen delivery (CDO2 ), with corresponding implications for the pathophysiology of the neurological syndrome, acute mountain sickness (AMS). Eight healthy men were randomly assigned single blind to 7 h of passive exposure to both normoxia (21% O2 ) and hypoxia (12% O2 ). The peripheral and central respiratory chemoreflex, internal carotid artery, external carotid artery (ECA) and vertebral artery blood flow (duplex ultrasound) and AMS scores (questionnaires) were measured throughout. A reduction in internal carotid artery CDO2 was observed during hypoxia despite a compensatory elevation in perfusion. In contrast, vertebral artery and ECA CDO2 were preserved, and the former was attributable to a more marked increase in perfusion. Hypoxia was associated with progressive activation of the peripheral respiratory chemoreflex (P < 0.001), whereas the central respiratory chemoreflex remained unchanged (P > 0.05). Symptom severity in participants who developed clinical AMS was positively related to ECA blood flow (Lake Louise score, r = 0.546-0.709, P = 0.004-0.043; Environmental Symptoms Questionnaires-Cerebral symptoms score, r = 0.587-0.771, P = 0.001-0.027, n = 4). Collectively, these findings highlight the site-specific regulation of CBF in hypoxia that maintains CDO2 selectively in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. Furthermore, ECA vasodilatation might represent a hitherto unexplored haemodynamic risk factor implicated in the pathophysiology of AMS.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Hayato Tsukamoto
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.,Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Angelo Iannetelli
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas S Owens
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas A Calverley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Lewis Fall
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Christopher J Marley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Takeshi Hashimoto
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | | | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
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13
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Turner REF, Gatterer H, Falla M, Lawley JS. High-altitude cerebral edema: its own entity or end-stage acute mountain sickness? J Appl Physiol (1985) 2021; 131:313-325. [PMID: 33856254 DOI: 10.1152/japplphysiol.00861.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
High-altitude cerebral edema (HACE) and acute mountain sickness (AMS) are neuropathologies associated with rapid exposure to hypoxia. However, speculation remains regarding the exact etiology of both HACE and AMS and whether they share a common mechanistic pathology. This review outlines the basic principles of HACE development, highlighting how edema could develop from 1) a progression from cytotoxic swelling to ionic edema or 2) permeation of the blood brain barrier (BBB) with or without ionic edema. Thereafter, discussion turns to the available neuroimaging literature in the context of cytotoxic, ionic, or vasogenic edema in both HACE and AMS. Although HACE is clearly caused by an increase in brain water of ionic and/or vasogenic origin, there is very little evidence that this type of edema is present when AMS develops. However, cerebral vasodilation, increased intracranial blood volume, and concomitant intracranial fluid shifts from the extracellular to the intracellular space, as interpreted from changes in diffusion indices within white matter, are observed consistently in persons acutely exposed to hypoxia and with AMS. Therefore, herein we explore the idea that intracellular swelling occurs alongside AMS, and is a critical precursor to extracellular ionic edema formation. We propose that this process produces a subtle modulation of the BBB, which either together with or independent of vasogenic edema provides a transvascular segue from the end-stage of AMS to HACE. Ultimately, this review seeks to shed light on the possible processes underlying HACE pathophysiology, and thus highlights potential avenues for future prevention and treatment.
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Affiliation(s)
- Rachel E F Turner
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Marika Falla
- Center for Mind/Brain Sciences and Centre for Neurocognitive Rehabilitation, University of Trento, Rovereto, Italy
| | - Justin S Lawley
- Division of Performance Physiology & Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
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14
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Janigro D, Bailey DM, Lehmann S, Badaut J, O'Flynn R, Hirtz C, Marchi N. Peripheral Blood and Salivary Biomarkers of Blood-Brain Barrier Permeability and Neuronal Damage: Clinical and Applied Concepts. Front Neurol 2021; 11:577312. [PMID: 33613412 PMCID: PMC7890078 DOI: 10.3389/fneur.2020.577312] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Within the neurovascular unit (NVU), the blood–brain barrier (BBB) operates as a key cerebrovascular interface, dynamically insulating the brain parenchyma from peripheral blood and compartments. Increased BBB permeability is clinically relevant for at least two reasons: it actively participates to the etiology of central nervous system (CNS) diseases, and it enables the diagnosis of neurological disorders based on the detection of CNS molecules in peripheral body fluids. In pathological conditions, a suite of glial, neuronal, and pericyte biomarkers can exit the brain reaching the peripheral blood and, after a process of filtration, may also appear in saliva or urine according to varying temporal trajectories. Here, we specifically examine the evidence in favor of or against the use of protein biomarkers of NVU damage and BBB permeability in traumatic head injury, including sport (sub)concussive impacts, seizure disorders, and neurodegenerative processes such as Alzheimer's disease. We further extend this analysis by focusing on the correlates of human extreme physiology applied to the NVU and its biomarkers. To this end, we report NVU changes after prolonged exercise, freediving, and gravitational stress, focusing on the presence of peripheral biomarkers in these conditions. The development of a biomarker toolkit will enable minimally invasive routines for the assessment of brain health in a broad spectrum of clinical, emergency, and sport settings.
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Affiliation(s)
- Damir Janigro
- Department of Physiology Case Western Reserve University, Cleveland, OH, United States.,FloTBI Inc., Cleveland, OH, United States
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, United Kingdom
| | - Sylvain Lehmann
- IRMB, INM, UFR Odontology, University Montpellier, INSERM, CHU Montpellier, CNRS, Montpellier, France
| | - Jerome Badaut
- Brain Molecular Imaging Lab, CNRS UMR 5287, INCIA, University of Bordeaux, Bordeaux, France
| | - Robin O'Flynn
- IRMB, INM, UFR Odontology, University Montpellier, INSERM, CHU Montpellier, CNRS, Montpellier, France
| | - Christophe Hirtz
- IRMB, INM, UFR Odontology, University Montpellier, INSERM, CHU Montpellier, CNRS, Montpellier, France
| | - Nicola Marchi
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U 1191 INSERM, University of Montpellier), Montpellier, France
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15
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Barclay H, Mukerji S, Kayser B, O'Donnell T, Tzeng YC, Hill S, Knapp K, Legg S, Frei D, Fan JL. Respiratory alkalinization and posterior cerebral artery dilatation predict acute mountain sickness severity during 10 h normobaric hypoxia. Exp Physiol 2020; 106:175-190. [PMID: 33347666 DOI: 10.1113/ep088938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? The pathophysiology of acute mountain sickness (AMS), involving the respiratory, renal and cerebrovascular systems, remains poorly understood. How do the early adaptations in these systems during a simulated altitude of 5000 m relate to AMS risk? What is the main finding and its importance? The rate of blood alkalosis and cerebral artery dilatation predict AMS severity during the first 10 h of exposure to a simulated altitude of 5000 m. Slow metabolic compensation by the kidneys of respiratory alkalosis attributable to a brisk breathing response together with excessive brain blood vessel dilatation might be involved in early development of AMS. ABSTRACT The complex pathophysiology of acute mountain sickness (AMS) remains poorly understood and is likely to involve maladaptive responses of the respiratory, renal and cerebrovascular systems to hypoxia. Using stepwise linear regression, we tested the hypothesis that exacerbated respiratory alkalosis, as a result of a brisk ventilatory response, sluggish renal compensation in acute hypoxia and dysregulation of cerebral perfusion predict AMS severity. We assessed the Lake Louise score (LLS, an index of AMS severity), fluid balance, ventilation, venous pH, bicarbonate, sodium and creatinine concentrations, body weight, urinary pH and cerebral blood flow [internal carotid artery (ICA) and vertebral artery (VA) blood flow and diameter], in 27 healthy individuals (13 women) throughout 10 h exposures to normobaric normoxia (fraction of inspired O2 = 0.21) and normobaric hypoxia (fraction of inspired O2 = 0.117, simulated 5000 m) in a randomized, single-blinded manner. In comparison to normoxia, hypoxia increased the LLS, ventilation, venous and urinary pH, and blood flow and diameter in the ICA and VA, while venous concentrations of both bicarbonate and creatinine were decreased (P < 0.001 for all). There were significant correlations between AMS severity and the rates of change in blood pH, sodium concentration and VA diameter and more positive fluid balance (P < 0.05). Stepwise regression found increased blood pH [beta coefficient (β) = 0.589, P < 0.001] and VA diameter (β = 0.418, P = 0.008) to be significant predictors of AMS severity in our cohort [F(2, 20) = 16.1, R2 = 0.617, P < 0.001, n = 24], accounting for 62% of the variance in peak LLS. Using classic regression variable selection, our data implicate the degree of respiratory alkalosis and cerebrovascular dilatation in the early stages of AMS development.
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Affiliation(s)
- Holly Barclay
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand.,Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Saptarshi Mukerji
- Emergency Department, Wellington Regional Hospital, Capital & Coast District Health Board, Wellington, New Zealand
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Terrence O'Donnell
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand.,Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Yu-Chieh Tzeng
- Wellington Medical Technology Group, Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand.,Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Stephen Hill
- School of Psychology, Massey University, Palmerston North, New Zealand
| | - Katie Knapp
- School of Psychology, Massey University, Palmerston North, New Zealand
| | - Stephen Legg
- Centre for Ergonomics, Occupational Health and Safety, Massey University, Palmerston North, New Zealand
| | - Dan Frei
- Department of Anaesthesia and Pain Medicine, Wellington Regional Hospital, Capital & Coast District Health Board, Wellington, New Zealand
| | - Jui-Lin Fan
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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16
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The Effects of On-Field Heat Index and Altitude on Concussion Assessments and Recovery Among NCAA Athletes. Sports Med 2020; 51:825-835. [PMID: 33332015 DOI: 10.1007/s40279-020-01395-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Recent literature has indicated altitude may be a protective factor for concussion but it is unknown whether altitude or heat index affects recovery. OBJECTIVE To examine whether on-field heat index and altitude at the time of injury alter acute (< 48 h) concussion assessments, days-to-asymptomatic, and days-to-return-to-play in collegiate athletes following concussion. METHODS Collegiate athletes (n = 187; age = 19.7 ± 1.4 years; male = 70.6%) underwent baseline assessments across 30 universities and experienced a concussion in this retrospective cohort study. Altitude (m) and heat index (°C) at the time and location of injury were determined using valid online database tools. Acute concussion assessments included the Sport Concussion Assessment Tool (SCAT) symptom inventory, Balance Error Scoring System (BESS), and the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). We used multiple linear regression models to determine whether heat index and altitude predicted each acute assessment outcome, days-to-asymptomatic, and days-to-return-to-play. RESULTS Collegiate athletes were concussed at a 181.1 m (range - 0.6 to 2201.9 m) median altitude and 17.8 °C (range - 6.1 to 35.6 °C) median heat index. Altitude did not predict (p ≥ 0.265) any outcomes. Every one-degree increase in heat index reduced days-to-asymptomatic (p = 0.047; R2 = 0.06) and days-to-return-to-play (p = 0.006; R2 = 0.09) by 0.05 and 0.14 days, respectively. Heat index and altitude did not explain significant variance in SCAT, BESS, and ImPACT composite scores (p's = 0.20-0.922). CONCLUSION Our findings suggest that on-field altitude and heat index at the time of injury do not contribute to clinically meaningful changes on acute assessments or concussion recovery. On-field altitude and heat index do not appear to significantly alter assessment outcomes or clinical recovery, suggesting that environmental factors at altitudes below < 2500 m are negligible outcomes for researchers and clinicians to consider post-concussion.
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17
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Dixon L, McNamara C, Gaur P, Mallon D, Coughlan C, Tona F, Jan W, Wilson M, Jones B. Cerebral microhaemorrhage in COVID-19: a critical illness related phenomenon? Stroke Vasc Neurol 2020; 5:315-322. [PMID: 33208493 PMCID: PMC7681795 DOI: 10.1136/svn-2020-000652] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/08/2020] [Accepted: 10/24/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Cerebral microhaemorrhages are increasingly being recognised as a complication of COVID-19. This observational retrospective study aims to further investigate the potential pathophysiology through assessing the pattern of microhaemorrhage and clinical characteristics of patients with COVID-19 and microhaemorrhage. By comparing with similar patterns of microhaemorrhage in other non-COVID-19 disease, this study aims to propose possible common pathogenic mechanisms. METHODS A retrospective observational case series was performed identifying all patients with COVID-19 complicated by cerebral microhaemorrhage on MRI. The distribution and number of microhaemorrhages were recorded using the microbleed anatomical scale, and patients' baseline characteristics and salient test results were also recorded. RESULTS Cerebral microhaemorrhages were noted to have a predilection for the corpus callosum, the juxtacortical white matter and brainstem. All patients had a preceding period of critical illness with respiratory failure and severe hypoxia necessitating intubation and mechanical ventilation. DISCUSSION This study demonstrates a pattern of cerebral microhaemorrhage that is similar to the pattern reported in patients with non-COVID-19 related critical illness and other causes of severe hypoxia. This raises questions regarding whether microhaemorrhage occurs from endothelial dysfunction due the direct effect of SARS-CoV-2 infection or from the secondary effects of critical illness and hypoxia.
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Affiliation(s)
- Luke Dixon
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Cillian McNamara
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Pritika Gaur
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Dermot Mallon
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Christopher Coughlan
- Department of Cardiac Intensive Care, Imperial College Healthcare NHS Trust, London, UK
| | - Francesca Tona
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Wajanat Jan
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Mark Wilson
- Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK
| | - Brynmor Jones
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
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18
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Biollaz J, Buclin T, Hildebrandt W, Décosterd LA, Nussberger J, Swenson ER, Bärtsch P. No renal dysfunction or salt and water retention in acute mountain sickness at 4,559 m among young resting males after passive ascent. J Appl Physiol (1985) 2020; 130:226-236. [PMID: 33180647 DOI: 10.1152/japplphysiol.00382.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examined the role and function of the kidney at high altitude in relation to fluid balance and the development of acute mountain sickness (AMS), avoiding confounders that have contributed to conflicting results in previous studies. We examined 18 healthy male resting volunteers (18-40 yr) not acclimatized to high altitude while on a controlled diet for 24 h at Lausanne (altitude: 560 m) followed by a period of 44 h after reaching the Regina Margherita hut (4,559 m) by helicopter. AMS scores peaked after 20 h at 4,559 m. AMS was defined as functional Lake Louise score ≥ 2. There were no significant differences between 10 subjects with and 8 subjects without AMS for urinary flow, fluid balance, and weight change. Sodium excretion rate was lower in those with AMS after 24 h at altitude. Microalbuminuria increased at altitude but was not different between the groups. Creatinine clearance was not affected by altitude or AMS, whereas clearances of sinistrin and p-aminohippuric acid decreased slightly, somewhat more in those without AMS. Plasma concentrations of epinephrine, norepinephrine, atrial natriuretic factor, and vasopressin increased whereas renin activity, angiotensin, and aldosterone decreased at altitude. Circulating hormone concentrations did not differ between those with and without AMS. Summarizing, in healthy resting young men flown by helicopter to 4,559 m, renal function was not affected by hypoxia except for minor microalbuminuria, high altitude diuresis did not occur, and AMS was not associated with salt and water retention or renal dysfunction.NEW & NOTEWORTHY Kidney function remained essentially unaffected and acute mountain sickness (AMS) was not associated with salt and water retention in healthy young men flown to and resting at the Margherita hut (4,559 m) under strictly controlled conditions maintaining water, salt, and food intake at pre-exposure levels. Thus, renal dysfunction and fluid retention are not essential factors contributing to the pathophysiology of AMS.
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Affiliation(s)
- Jérôme Biollaz
- Service of Clinical Pharmacology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Thierry Buclin
- Service of Clinical Pharmacology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Wulf Hildebrandt
- Institute of Anatomy and Cell Biology, Philipps-University of Marburg, Marburg, Germany.,Department of Internal Medicine, University Clinic, Heidelberg, Germany
| | - Laurent A Décosterd
- Service of Clinical Pharmacology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Jürg Nussberger
- Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Erik R Swenson
- Department of Internal Medicine, University Clinic, Heidelberg, Germany.,Pulmonary and Critical Care Medicine, Medical Service, Veterans Affairs Puget Sound Health Care System, University of Washington, Seattle, Washington
| | - Peter Bärtsch
- Department of Internal Medicine, University Clinic, Heidelberg, Germany
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19
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Benveniste H, Elkin R, Heerdt PM, Koundal S, Xue Y, Lee H, Wardlaw J, Tannenbaum A. The glymphatic system and its role in cerebral homeostasis. J Appl Physiol (1985) 2020; 129:1330-1340. [PMID: 33002383 DOI: 10.1152/japplphysiol.00852.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The brain's high bioenergetic state is paralleled by high metabolic waste production. Authentic lymphatic vasculature is lacking in brain parenchyma. Cerebrospinal fluid (CSF) flow has long been thought to facilitate central nervous system detoxification in place of lymphatics, but the exact processes involved in toxic waste clearance from the brain remain incompletely understood. Over the past 8 yr, novel data in animals and humans have begun to shed new light on these processes in the form of the "glymphatic system," a brain-wide perivascular transit passageway dedicated to CSF transport and interstitial fluid exchange that facilitates metabolic waste drainage from the brain. Here we will discuss glymphatic system anatomy and methods to visualize and quantify glymphatic system (GS) transport in the brain and also discuss physiological drivers of its function in normal brain and in neurodegeneration.
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Affiliation(s)
- Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Rena Elkin
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
| | - Paul M Heerdt
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Yuechuan Xue
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Joanna Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, Dementia Research Institute at the University of Edinburgh, Edinburgh, United Kingdom
| | - Allen Tannenbaum
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
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20
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Stringer MS, Lee H, Huuskonen MT, MacIntosh BJ, Brown R, Montagne A, Atwi S, Ramirez J, Jansen MA, Marshall I, Black SE, Zlokovic BV, Benveniste H, Wardlaw JM. A Review of Translational Magnetic Resonance Imaging in Human and Rodent Experimental Models of Small Vessel Disease. Transl Stroke Res 2020; 12:15-30. [PMID: 32936435 PMCID: PMC7803876 DOI: 10.1007/s12975-020-00843-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/16/2020] [Accepted: 08/19/2020] [Indexed: 12/29/2022]
Abstract
Cerebral small vessel disease (SVD) is a major health burden, yet the pathophysiology remains poorly understood with no effective treatment. Since much of SVD develops silently and insidiously, non-invasive neuroimaging such as MRI is fundamental to detecting and understanding SVD in humans. Several relevant SVD rodent models are established for which MRI can monitor in vivo changes over time prior to histological examination. Here, we critically review the MRI methods pertaining to salient rodent models and evaluate synergies with human SVD MRI methods. We found few relevant publications, but argue there is considerable scope for greater use of MRI in rodent models, and opportunities for harmonisation of the rodent-human methods to increase the translational potential of models to understand SVD in humans. We summarise current MR techniques used in SVD research, provide recommendations and examples and highlight practicalities for use of MRI SVD imaging protocols in pre-selected, relevant rodent models.
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Affiliation(s)
- Michael S Stringer
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Mikko T Huuskonen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bradley J MacIntosh
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Rosalind Brown
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Axel Montagne
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Sarah Atwi
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Joel Ramirez
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Maurits A Jansen
- Edinburgh Preclinical Imaging, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Ian Marshall
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Sandra E Black
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada.,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Joanna M Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK. .,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
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21
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Berger MM, Sareban M, Bärtsch P. Acute mountain sickness: Do different time courses point to different pathophysiological mechanisms? J Appl Physiol (1985) 2020; 128:952-959. [DOI: 10.1152/japplphysiol.00305.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Acute mountain sickness (AMS) is a syndrome of nonspecific symptoms (i.e., headache, anorexia, nausea, vomiting, dizziness, and fatigue) that may develop in nonacclimatized individuals after rapid exposure to altitudes ≥2,500 m. In field studies, mean AMS scores usually peak after the first night at a new altitude. Analyses of the individual time courses of AMS in four studies performed at 3,450 m and 4,559 m revealed that three different patterns are hidden in the above-described overall picture. In 41% of those who developed AMS (i.e., AMS-C score >0.70), symptoms peaked on day 1, in 39%, symptoms were most prominent on day 2, and in 20%, symptoms were most prominent on day 3. We suggest to name the different time courses of AMS type I, type II, and type III, respectively. Here, we hypothesize that the variation of time courses of AMS are caused by different pathophysiological mechanisms. This assumption could explain why no consistent correlations between an overall assessment of AMS and single pathophysiological factors have been found in a large number of studies over the past 50 yr. In this paper, we will briefly review the fundamental mechanisms implicated in the pathophysiology of AMS and discuss how they might contribute to the three different AMS time courses.
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Affiliation(s)
- Marc M. Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Germany
| | - Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Peter Bärtsch
- Department of Internal Medicine, University of Heidelberg, Heidelberg, Germany
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22
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Clarke AK, Cozzi M, Imray CHE, Wright A, Pagliarini S. Analysis of Retinal Segmentation Changes at High Altitude With and Without Acetazolamide. Invest Ophthalmol Vis Sci 2019; 60:36-40. [PMID: 30601929 DOI: 10.1167/iovs.18-24966] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Our aim was to assess retinal venous diameter and segmented retinal layer thickness variation in acute systemic hypoxia with and without acetazolamide and to relate these changes to high altitude headache (HAH), as a proxy for intracerebral pathophysiology. Methods A total of 20 subjects participated in a 4-day ascent to the Margherita Hut (4,559 m) on Monte Rosa in the Italian Alps. Each participant was randomized to either oral acetazolamide 250 mg twice daily or placebo. A combination of digital imaging and optical coherence tomography was used to measure retinal vessel diameter and retinal layer thickness. Clinically-assessed HAH was recorded. Results A total of 18 participants had usable digital and OCT images, with 12 developing HAH. Significant thickening was seen only in the two inner layers of the retina, the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) at P = 0.012 and P = 0.010, respectively, independent of acetazolamide. There was a significant positive correlation between HAH and both retinal venous diameter (T = 4.953, P = 0.001) and retinal artery diameter (T = 2.865, P = 0.015), with both unaffected by acetazolamide (F = 0.439, P = 0.518). Conclusions Retinal venous diameter correlates positively with HAH, adding further evidence for the proposed venous outflow limitation mechanism. The inner layers of the retina swelled disproportionately when compared to the outer layers under conditions of systemic hypoxia. Acetazolamide does not appear to influence altitudinal changes of retinal layers and vasculature.
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Affiliation(s)
| | - Mariano Cozzi
- University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom
| | | | - Alex Wright
- College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sergio Pagliarini
- University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom
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23
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Abstract
Mountain climbers may develop specific illnesses that largely depend on the altitude reached and the rate of ascent. The popularity of travel to high altitude destinations, extreme tourist activities and mountain climbing means that neurologists in low-altitude countries are increasingly likely to encounter neurological problems and disorders in people exposed to high altitude. Additionally, they may have to advise patients with pre-existing neurological conditions on the risks of ascent to altitude. This article focuses on neurological-related high-altitude illnesses: acute mountain sickness and high-altitude cerebral oedema, as well as high-altitude retinopathy and other neurological disorders. This overview combines current understood pathogenesis with the experience of managing altitude-related illness at the foot of Mount Kilimanjaro in northern Tanzania, the tallest free-standing mountain in the world.
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24
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Joyce K, Lucas S, Imray C, Balanos G, Wright AD. Advances in the available non-biological pharmacotherapy prevention and treatment of acute mountain sickness and high altitude cerebral and pulmonary oedema. Expert Opin Pharmacother 2018; 19:1891-1902. [DOI: 10.1080/14656566.2018.1528228] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- K.E. Joyce
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - S.J.E. Lucas
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - C.H.E. Imray
- Department of Vascular Surgery, University Hospitals of Coventry and Warwickshire; Warwick Medical School, Coventry, UK
| | - G.M Balanos
- School of Sport, Exercise, & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - A. D. Wright
- Department of Medicine, University of Birmingham, Edgbaston, UK
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25
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Schatz A, Guggenberger V, Fischer MD, Schommer K, Bartz-Schmidt KU, Gekeler F, Willmann G. Optic nerve oedema at high altitude occurs independent of acute mountain sickness. Br J Ophthalmol 2018; 103:bjophthalmol-2018-312224. [PMID: 29973364 DOI: 10.1136/bjophthalmol-2018-312224] [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: 03/10/2018] [Accepted: 06/14/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND/AIMS The study aims to investigate changes in the optic nerve sheath diameter (ONSD) at high altitude and to assess correlation to optic disc oedema (ODE) and acute mountain sickness (AMS). This investigation is part of the Tübingen High Altitude Ophthalmology study. METHODS Fourteen volunteers ascended to 4559 m for 4 days before returning to low altitude. Ultrasonography of ONSD, quantification of optic disc parameters using a scanning laser ophthalmoscope and fluorescein angiography were performed at 341 m and at high altitude. Pearson's coefficient was used to correlate changes in ONSD with the optic disc and AMS. Assessment of AMS was performed using the Lake Louise (LL) and AMS-cerebral (AMS-C) scores of the Environmental Symptom Questionnaire-III. All volunteers were clinically monitored for heart rate (HR) and oxygen saturation (SpO2). RESULTS The mean ONSD at high altitude (4.6±0.3 mm, p<0.05) was significantly increased compared with baseline (3.8±0.4 mm) and remained enlarged throughout high-altitude exposure. This change in ONSD did not correlate with AMS (AMS-C, r=0.26, p=0.37; LL, r=0.21, p=0.48) and high-altitude headache (r=0.54, p=0.046), or clinical parameters of SpO2 (r=0.11, p=0.72) and HR (r=0.22, p=0.44). Increased ONSD did not correlate with altered key stereometric parameters of the optic disc describing ODE at high altitude (r<0.1, p>0.5). CONCLUSION High-altitude exposure leads to marked oedema formation of the optic nerve independent of AMS. Increased ONSD and ODE reflect hypoxia-driven oedema formation of the optic nerve at high altitude, providing important pathophysiological insight into high-altitude illness development and for future research.
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Affiliation(s)
- Andreas Schatz
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
| | | | - M Dominik Fischer
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Kai Schommer
- Medizinischer Dienst der Krankenversicherungen, MDK Baden-Württemberg, Mannheim, Germany
| | | | - Florian Gekeler
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
| | - Gabriel Willmann
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
- Department of Ophthalmology, Katharinenhospital, Stuttgart, Germany
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26
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Muza SR. Wearable physiological sensors and real-time algorithms for detection of acute mountain sickness. J Appl Physiol (1985) 2018; 124:557-563. [DOI: 10.1152/japplphysiol.00367.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This is a minireview of potential wearable physiological sensors and algorithms (process and equations) for detection of acute mountain sickness (AMS). Given the emerging status of this effort, the focus of the review is on the current clinical assessment of AMS, known risk factors (environmental, demographic, and physiological), and current understanding of AMS pathophysiology. Studies that have examined a range of physiological variables to develop AMS prediction and/or detection algorithms are reviewed to provide insight and potential technological roadmaps for future development of real-time physiological sensors and algorithms to detect AMS. Given the lack of signs and nonspecific symptoms associated with AMS, development of wearable physiological sensors and embedded algorithms to predict in the near term or detect established AMS will be challenging. Prior work using [Formula: see text], HR, or HRv has not provided the sensitivity and specificity for useful application to predict or detect AMS. Rather than using spot checks as most prior studies have, wearable systems that continuously measure SpO2 and HR are commercially available. Employing other statistical modeling approaches such as general linear and logistic mixed models or time series analysis to these continuously measured variables is the most promising approach for developing algorithms that are sensitive and specific for physiological prediction or detection of AMS.
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Affiliation(s)
- Stephen R. Muza
- Strategic Science Management Office, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
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27
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Plasma proteomic study of acute mountain sickness susceptible and resistant individuals. Sci Rep 2018; 8:1265. [PMID: 29352170 PMCID: PMC5775437 DOI: 10.1038/s41598-018-19818-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 12/20/2017] [Indexed: 12/20/2022] Open
Abstract
Although extensive studies have focused on the development of acute mountain sickness (AMS), the exact mechanisms of AMS are still obscure. In this study, we used isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis to identify novel AMS−associated biomarkers in human plasma. After 9 hours of hypobaric hypoxia the abundance of proteins related to tricarboxylic acid (TCA) cycle, glycolysis, ribosome, and proteasome were significantly reduced in AMS resistant (AMS−) group, but not in AMS susceptible (AMS+) group. This suggested that AMS− individuals could reduce oxygen consumption via repressing TCA cycle and glycolysis, and reduce energy consumption through decreasing protein degradation and synthesis compared to AMS+ individuals after acute hypoxic exposure. The inflammatory response might be decreased resulting from the repressed TCA cycle. We propose that the ability for oxygen consumption reduction may play an important role in the development of AMS. Our present plasma proteomic study in plateau of the Han Chinese volunteers gives new data to address the development of AMS and potential AMS correlative biomarkers.
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28
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Rossetti GMK, Macdonald JH, Wylie LJ, Little SJ, Newton V, Wood B, Hawkins KA, Beddoe R, Davies HE, Oliver SJ. Dietary nitrate supplementation increases acute mountain sickness severity and sense of effort during hypoxic exercise. J Appl Physiol (1985) 2017; 123:983-992. [DOI: 10.1152/japplphysiol.00293.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/28/2017] [Accepted: 07/01/2017] [Indexed: 12/12/2022] Open
Abstract
Dietary nitrate supplementation enhances sea level performance and may ameliorate hypoxemia at high altitude. However, nitrate may exacerbate acute mountain sickness (AMS), specifically headache. This study investigated the effect of nitrate supplementation on AMS symptoms and exercise responses with 6-h hypoxia. Twenty recreationally active men [age, 22 ± 4 yr, maximal oxygen consumption (V̇o2max), 51 ± 6 ml·min−1·kg−1, means ± SD] completed this randomized double-blinded placebo-controlled crossover study. Twelve participants were classified as AMS− on the basis of Environmental Symptoms Questionnaire [Acute Cerebral Mountain Sickness score (AMS-C)] <0.7 in both trials, and five participants were classified as AMS+ on the basis of AMS-C ≥0.7 on placebo. Five days of nitrate supplementation (70-ml beetroot juice containing ~6.4 mmol nitrate daily) increased plasma NO metabolites by 182 µM compared with placebo but did not reduce AMS or improve exercise performance. After 4-h hypoxia [inspired O2 fraction ([Formula: see text]) = 0.124], nitrate increased AMS-C and headache severity (visual analog scale; whole sample ∆10 [1, 20] mm, mean difference [95% confidence interval]; P = 0.03) compared with placebo. In addition, after 5-h hypoxia, nitrate increased sense of effort during submaximal exercise (∆7 [−1, 14]; P = 0.07). In AMS−, nitrate did not alter headache or sense of effort. In contrast, in AMS+, nitrate increased headache severity (∆26 [−3, 56] mm; P = 0.07), sense of effort (∆14 [1, 28]; P = 0.04), oxygen consumption, ventilation, and mean arterial pressure during submaximal exercise. On the next day, in a separate acute hypoxic exercise test ([Formula: see text] = 0.141), nitrate did not improve time to exhaustion at 80% hypoxic V̇o2max. In conclusion, dietary nitrate increases AMS and sense of effort during exercise, particularly in those who experience AMS. Dietary nitrate is therefore not recommended as an AMS prophylactic or ergogenic aid in nonacclimatized individuals at altitude. NEW & NOTEWORTHY This is the first study to identify that the popular dietary nitrate supplement (beetroot) does not reduce acute mountain sickness (AMS) or improve exercise performance during 6-h hypoxia. The consumption of nitrate in those susceptible to AMS exacerbates AMS symptoms (headache) and sense of effort and raises oxygen cost, ventilation, and blood pressure during walking exercise in 6-h hypoxia. These data question the suitability of nitrate supplementation during altitude travel in nonacclimatized people.
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Affiliation(s)
- Gabriella M. K. Rossetti
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Jamie H. Macdonald
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Lee J. Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Exeter, United Kingdom
| | - Samuel J. Little
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Victoria Newton
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Benjamin Wood
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Kieran A. Hawkins
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Rhys Beddoe
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Hannah E. Davies
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Samuel J. Oliver
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
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Chao AC, Han K, Chang FC, Hsu HY, Chung CP, Sheng WY, Chan L, Wu J, Hu HH. Ultrasound diagnosis of transverse sinus hypoplasia using flow profiles of the internal jugular vein. PLoS One 2017; 12:e0181119. [PMID: 28704516 PMCID: PMC5509311 DOI: 10.1371/journal.pone.0181119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/25/2017] [Indexed: 11/19/2022] Open
Abstract
Accurate diagnosis of subtypes of transverse sinus (TS) hypoplasia requires more expensive methods like magnetic resonance (MR) imaging. We hypothesized ultrasound findings of the internal jugular vein (IJV) can be surrogate indicators for diagnosis of TS hypoplasia. MR images were reviewed in 131 subjects to evaluate TS diameter and the location and degree of venous flow stenosis and obstruction. Ultrasound parameters including the cross-sectional lumen area (CSA), time-average-mean velocity (TAMV), and flow volume (FV) at each IJV segment were also evaluated. Sixty-nine subjects had TS hypoplasia based on MRV criteria, of which 39 TS hypoplasia were considered a subtype of TS hypoplasia, which is secondary to the downstream venous compression/stenosis or left brachiocephalic vein. In the ultrasound study, the CSA of the IJV ipsilateral to TS hypoplasia was significantly smaller. Further, a contralateral/ipsilateral IJV CSA ratio >1.55 provided good sensitivity, specificity, and positive predictive value for discriminating TS hypoplasia.
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Affiliation(s)
- A-Ching Chao
- Department of Neurology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ke Han
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, Jilin, China
- * E-mail: (HHH); (KH)
| | - Feng-Chi Chang
- Department of Radiology, Taipei Veterans General Hospital and National Yang Ming University, Taipei, Taiwan
| | - Hung-Yi Hsu
- Department of Neurology, Tungs’ Taichung Metro Harbor Hospital, Taichung, Taiwan
| | - Chih-Ping Chung
- Department of Neurology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Wen-Yung Sheng
- Department of Neurology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Lung Chan
- Department of Neurology, Taipei Medical University-Shaung Ho Hospital, Taipei, Taiwan
| | - Jiang Wu
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, Jilin, China
| | - Han-Hwa Hu
- Department of Neurology, Taipei Medical University-Shaung Ho Hospital, Taipei, Taiwan
- Cerebrovascular Treatment and Research Center, College of Medicine, Taipei Medical University, Taipei, Taiwan
- * E-mail: (HHH); (KH)
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30
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Xiong J, Lu H, Wang R, Jia Z. Efficacy of ibuprofen on prevention of high altitude headache: A systematic review and meta-analysis. PLoS One 2017. [PMID: 28632763 PMCID: PMC5478153 DOI: 10.1371/journal.pone.0179788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Objective Ibuprofen is used to prevent high altitude headache (HAH) but its efficacy remains controversial. We conducted a systematic review and meta-analysis of randomized, placebo-controlled trials (RCTs) of ibuprofen for the prevention of HAH. Methods Studies reporting efficacy of ibuprofen for prevention of HAH were identified by searching electronic databases (until December 2016). The primary outcome was the difference in incidence of HAH between ibuprofen and placebo groups. Risk ratios (RR) were aggregated using a Mantel-Haenszel random effect model. Heterogeneity of included trials was assessed using the I2 statistics. Results In three randomized-controlled clinical trials involving 407 subjects, HAH occurred in 101 of 239 subjects (42%) who received ibuprofen and 96 of 168 (57%) who received placebo (RR = 0.79, 95% CI 0.66 to 0.96, Z = 2.43, P = 0.02, I2 = 0%). The absolute risk reduction (ARR) was 15%. Number needed to treat (NNT) to prevent HAH was 7. Similarly, The incidence of severe HAH was significant in the two groups (RR = 0.40, 95% CI 0.17 to 0.93, Z = 2.14, P = 0.03, I2 = 0%). Severe HAH occurred in 3% treated with ibuprofen and 10% with placebo. The ARR was 8%. NNT to prevent severe HAH was 13. Headache severity using a visual analogue scale was not different between ibuprofen and placebo. Similarly, the difference between the two groups in the change in SpO2 from baseline to altitude was not different. One included RCT reported one participant with black stools and three participants with stomach pain in the ibuprofen group, while seven participants reported stomach pain in the placebo group. Conclusions Based on a limited number of studies ibuprofen seems efficacious for the prevention of HAH and may therefore represent an alternative for preventing HAH with acetazolamide or dexamethasone.
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Affiliation(s)
- Juan Xiong
- Key Laboratory of the plateau of the environmental damage control, Lanzhou General Hospital of Lanzhou Military Command, Lanzhou, China
| | - Hui Lu
- Key Laboratory of the plateau of the environmental damage control, Lanzhou General Hospital of Lanzhou Military Command, Lanzhou, China
- * E-mail: (HL); (ZPJ)
| | - Rong Wang
- Key Laboratory of the plateau of the environmental damage control, Lanzhou General Hospital of Lanzhou Military Command, Lanzhou, China
| | - Zhengping Jia
- Key Laboratory of the plateau of the environmental damage control, Lanzhou General Hospital of Lanzhou Military Command, Lanzhou, China
- * E-mail: (HL); (ZPJ)
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31
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Liu B, Chen J, Zhang L, Gao Y, Cui J, Zhang E, Xu G, Liang Y, Liang Y, Wang J, Gao Y. IL-10 Dysregulation in Acute Mountain Sickness Revealed by Transcriptome Analysis. Front Immunol 2017; 8:628. [PMID: 28611780 PMCID: PMC5447681 DOI: 10.3389/fimmu.2017.00628] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 05/11/2017] [Indexed: 12/24/2022] Open
Abstract
Acute mountain sickness (AMS), which may progress to life-threatening high-altitude cerebral edema, is a major threat to millions of people who live in or travel to high altitude. Although studies have revealed the risk factors and pathophysiology theories of AMS, the molecular mechanisms of it do not comprehensively illustrate. Here, we used a system-level methodology, RNA sequencing, to explore the molecular mechanisms of AMS at genome-wide level in 10 individuals. After exposure to high altitude, a total of 1,164 and 1,322 differentially expressed transcripts were identified in AMS and non-AMS groups, respectively. Among them, only 328 common transcripts presented between the two groups. Immune and inflammatory responses were overrepresented in participants with AMS, but not in non-AMS individuals. Anti-inflammatory cytokine IL10 and inflammation cytokines IF17F and CCL8 exhibited significantly different genetic connectivity in AMS compared to that of non-AMS individuals based on network analysis. IL10 was downregulated and both IF17F and CCL8 were upregulated in AMS individuals. Moreover, the serum concentration of IL10 significantly decreased in AMS patients after exposure to high altitude (p = 0.001) in another population (n = 22). There was a large negative correlation between the changes in IL10 concentration, r(22) = −0.52, p = 0.013, and Lake Louise Score. Taken together, our analysis provides unprecedented characterization of AMS transcriptome and identifies that genes involved in immune and inflammatory responses were disturbed in AMS individuals by high-altitude exposure. The reduction of IL10 after exposure to high altitude was associated with AMS.
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Affiliation(s)
- Bao Liu
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
| | - Jian Chen
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
| | | | - Yixing Gao
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
| | - Jianhua Cui
- Research Center of PLA for Prevention and Treatment of High Mountain Sickness, The 18th Hospital of PLA, Xinjiang, China
| | - Erlong Zhang
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
| | - Gang Xu
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
| | | | | | | | - Yuqi Gao
- Institute of Medicine and Hygienic Equipment for High Altitude Region, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Medicine, PLA, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Third Military Medical University, Ministry of Education, Chongqing, China
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32
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Liu W, Liu J, Lou X, Zheng D, Wu B, Wang DJJ, Ma L. A longitudinal study of cerebral blood flow under hypoxia at high altitude using 3D pseudo-continuous arterial spin labeling. Sci Rep 2017; 7:43246. [PMID: 28240265 PMCID: PMC5327438 DOI: 10.1038/srep43246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/20/2017] [Indexed: 12/14/2022] Open
Abstract
Changes in cerebral blood flow (CBF) may occur with acute exposure to high altitude; however, the CBF of the brain parenchyma has not been studied to date. In this study, identical magnetic resonance scans using arterial spin labeling (ASL) were performed to study the haemodynamic changes at both sea level and high altitude. We found that with acute exposure to high altitude, the CBF in acute mountain sickness (AMS) subjects was higher (P < 0.05), while the CBF of non-AMS subjects was lower (P > 0.05) compared with those at sea level. Moreover, magnetic resonance angiography in both AMS and non-AMS subjects showed a significant increase in the cross-sectional areas of the internal carotid, basilar, and middle cerebral arteries on the first day at high altitude. These findings support that AMS may be related to increased CBF rather than vasodilation; these results contradict most previous studies that reported no relationship between CBF changes and the occurrence of AMS. This discrepancy may be attributed to the use of ASL for CBF measurement at both sea level and high altitude in this study, which has substantial advantages over transcranial Doppler for the assessment of CBF.
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Affiliation(s)
- Wenjia Liu
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Jie Liu
- Department of Radiology, Tibet Military General Hospital, Lhasa, Tibet, China
| | - Xin Lou
- Department of Radiology, Chinese PLA General Hospital, Beijing, China.,Department of Neurology, University of California, Los Angeles, CA, USA
| | - Dandan Zheng
- GE Healthcare, MR Research China, Beijing, China
| | - Bing Wu
- GE Healthcare, MR Research China, Beijing, China
| | - Danny J J Wang
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Lin Ma
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
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Grewal P, Smith JH. When Headache Warns of Homeostatic Threat: the Metabolic Headaches. Curr Neurol Neurosci Rep 2017; 17:1. [PMID: 28097510 DOI: 10.1007/s11910-017-0714-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Parneet Grewal
- Department of Neurology, University of Kentucky, 740 S. Limestone, L445, Lexington, KY, 40536, USA
| | - Jonathan H Smith
- Department of Neurology, University of Kentucky, 740 S. Limestone, L445, Lexington, KY, 40536, USA.
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Sagoo RS, Hutchinson CE, Wright A, Handford C, Parsons H, Sherwood V, Wayte S, Nagaraja S, Ng'Andwe E, Wilson MH, Imray CH. Magnetic Resonance investigation into the mechanisms involved in the development of high-altitude cerebral edema. J Cereb Blood Flow Metab 2017; 37:319-331. [PMID: 26746867 PMCID: PMC5167111 DOI: 10.1177/0271678x15625350] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/08/2015] [Accepted: 11/27/2015] [Indexed: 11/20/2022]
Abstract
Rapid ascent to high altitude commonly results in acute mountain sickness, and on occasion potentially fatal high-altitude cerebral edema. The exact pathophysiological mechanisms behind these syndromes remain to be determined. We report a study in which 12 subjects were exposed to a FiO2 = 0.12 for 22 h and underwent serial magnetic resonance imaging sequences to enable measurement of middle cerebral artery velocity, flow and diameter, and brain parenchymal, cerebrospinal fluid and cerebral venous volumes. Ten subjects completed 22 h and most developed symptoms of acute mountain sickness (mean Lake Louise Score 5.4; p < 0.001 vs. baseline). Cerebral oxygen delivery was maintained by an increase in middle cerebral artery velocity and diameter (first 6 h). There appeared to be venocompression at the level of the small, deep cerebral veins (116 cm3 at 2 h to 97 cm3 at 22 h; p < 0.05). Brain white matter volume increased over the 22-h period (574 ml to 587 ml; p < 0.001) and correlated with cumulative Lake Louise scores at 22 h (p < 0.05). We conclude that cerebral oxygen delivery was maintained by increased arterial inflow and this preceded the development of cerebral edema. Venous outflow restriction appeared to play a contributory role in the formation of cerebral edema, a novel feature that has not been observed previously.
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Affiliation(s)
- Ravjit S Sagoo
- Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK
| | - Charles E Hutchinson
- Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.,Warwick Medical School, University of Warwick, Coventry, West Midlands, UK
| | - Alex Wright
- College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Charles Handford
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Helen Parsons
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, West Midlands, UK
| | - Victoria Sherwood
- Department of Medical Physics, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK
| | - Sarah Wayte
- Department of Medical Physics, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK
| | - Sanjoy Nagaraja
- Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK
| | - Eddie Ng'Andwe
- Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK
| | - Mark H Wilson
- Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK
| | - Christopher He Imray
- Warwick Medical School, University of Warwick, Coventry, West Midlands, UK .,Department of Surgery, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.,Coventry University, West Midlands, UK
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Neumann T, Baertschi M, Vilser W, Drinda S, Franz M, Brückmann A, Wolf G, Jung C. Retinal vessel regulation at high altitudes1. Clin Hemorheol Microcirc 2016; 63:281-92. [DOI: 10.3233/ch-162041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Thomas Neumann
- Department of Internal Medicine III, Jena University Hospital, Jena, Germany
| | - Michael Baertschi
- Department of Ophthalmology, University of Basel, Switzerland
- Eyeness AG, Bern, Switzerland
| | | | | | - Marcus Franz
- Department of Internal Medicine I, Jena University Hospital, Jena, Germany
| | | | - Gunter Wolf
- Department of Internal Medicine III, Jena University Hospital, Jena, Germany
| | - Christian Jung
- University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Medical Faculty, Division of Cardiology, Pulmonology and Vascular Medicine, Düsseldorf, Germany
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Verges S, Rupp T, Villien M, Lamalle L, Troprés I, Poquet C, Warnking JM, Estève F, Bouzat P, Krainik A. Multiparametric Magnetic Resonance Investigation of Brain Adaptations to 6 Days at 4350 m. Front Physiol 2016; 7:393. [PMID: 27660613 PMCID: PMC5014870 DOI: 10.3389/fphys.2016.00393] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/23/2016] [Indexed: 11/26/2022] Open
Abstract
Objective: Hypoxic exposure in healthy subjects can induce acute mountain sickness including headache, lethargy, cerebral dysfunction, and substantial cerebral structural alterations which, in worst case, can lead to potentially fatal high altitude cerebral edema. Within this context, the relationships between high altitude-induced cerebral edema, changes in cerebral perfusion, increased brain parenchyma volume, increased intracranial pressure, and symptoms remain unclear. Methods: In 11 subjects before and after 6 days at 4350 m, we performed multiparametric magnetic resonance investigations including anatomical, apparent diffusion coefficient and arterial spin labeling sequences. Results: After the altitude stay, while subjects were asymptomatic, white matter volume (+0.7 ± 0.4%, p = 0.005), diffusion (+1.7 ± 1.4%, p = 0.002), and cerebral blood flow (+28 ± 38%; p = 0.036) were significantly increased while cerebrospinal fluid volume was reduced (−1.4 ± 1.1%, p = 0.009). Optic nerve sheath diameter (used as an index of increased intracranial pressure) was unchanged from before (5.84 ± 0.53 mm) to after (5.92 ± 0.60 mm, p = 0.390) altitude exposure. Correlations were observed between increases in white matter volume and diffusion (rho = 0.81, p = 0.016) and between changes in CSF volume and changes in ONSD s (rho = −0.92, p = 0.006) and symptoms during the altitude stay (rho = −0.67, p = 0.031). Conclusions: These data demonstrate white matter alterations after several days at high altitude when subjects are asymptomatic that may represent the normal brain response to prolonged high altitude exposure.
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Affiliation(s)
- Samuel Verges
- HP2 Laboratory, Université Grenoble AlpesGrenoble, France; U1042, Institut National de la Santé et de la Recherche MédicaleGrenoble, France
| | - Thomas Rupp
- HP2 Laboratory, Université Grenoble AlpesGrenoble, France; U1042, Institut National de la Santé et de la Recherche MédicaleGrenoble, France; Inter-Universitary Laboratory of Human Movement Biology, Université Savoie Mont BlancChambéry, France
| | - Marjorie Villien
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
| | - Laurent Lamalle
- U836, Institut National de la Santé et de la Recherche Médicale Grenoble, France
| | - Irène Troprés
- U836, Institut National de la Santé et de la Recherche Médicale Grenoble, France
| | - Camille Poquet
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
| | - Jan M Warnking
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
| | - François Estève
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
| | - Pierre Bouzat
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
| | - Alexandre Krainik
- Grenoble Institute of Neurosciences, Université Grenoble AlpesGrenoble, France; SFR1, Université Grenoble AlpesGrenoble, France
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Imray C. Lessons from altitude: cerebral perfusion insights and their potential translational clinical significance. Exp Physiol 2016; 101:1167-1172. [PMID: 27061345 DOI: 10.1113/ep085813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/30/2016] [Indexed: 01/28/2023]
Abstract
What is the topic of this review? The long-held assumption that transcranial Doppler middle cerebral artery velocity is a surrogate for cerebral blood flow has been questioned in certain circumstances, particularly where tissue oxygenation changes. What advances does it highlight? Cerebral venous outflow restriction appears to be implicated in the development of high-altitude cerebral oedema. Rapid ascent to high altitude commonly results in acute mountain sickness and, on occasion, potentially fatal high-altitude cerebral oedema. The exact pathophysiological mechanisms behind these syndromes remain to be determined. One of the main theories to explain the development of acute mountain sickness is an increase in intracranial pressure. Vasogenic (extracellular water accumulation attributable to increased permeability of the blood-brain barrier) and cytotoxic (intracellular) oedema have also been postulated as potential mechanisms that underlie high-altitude cerebral oedema. Recently published findings derived from a very challenging field study (obtained at altitudes of up to 7950 m), substantiated by sea-level hypoxic magnetic resonance angiography studies, have given new insights into the maintenance of cerebral blood flow at altitude. This report provides new perspectives and potential mechanisms to account for the maintenance of cerebral oxygen delivery at high and extreme altitude. In particular, the long-held assumption that transcranial Doppler middle cerebral artery velocity is a surrogate for cerebral blood flow has been shown to be incorrect in certain circumstances. The emerging evidence for a potential third mechanism, namely the restrictive venous outflow hypothesis, in the development of high-altitude cerebral oedema, over and above the accepted vasogenic and cytotoxic hypotheses, is also appraised.
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Affiliation(s)
- Chris Imray
- Department of Vascular Surgery, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK.,Warwick Medical School, Warwick University, Coventry, UK.,Coventry University, Coventry, UK
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Wilson MH. Monro-Kellie 2.0: The dynamic vascular and venous pathophysiological components of intracranial pressure. J Cereb Blood Flow Metab 2016; 36:1338-50. [PMID: 27174995 PMCID: PMC4971608 DOI: 10.1177/0271678x16648711] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/05/2016] [Accepted: 04/17/2016] [Indexed: 12/16/2022]
Abstract
For 200 years, the 'closed box' analogy of intracranial pressure (ICP) has underpinned neurosurgery and neuro-critical care. Cushing conceptualised the Monro-Kellie doctrine stating that a change in blood, brain or CSF volume resulted in reciprocal changes in one or both of the other two. When not possible, attempts to increase a volume further increase ICP. On this doctrine's "truth or relative untruth" depends many of the critical procedures in the surgery of the central nervous system. However, each volume component may not deserve the equal weighting this static concept implies. The slow production of CSF (0.35 ml/min) is dwarfed by the dynamic blood in and outflow (∼700 ml/min). Neuro-critical care practice focusing on arterial and ICP regulation has been questioned. Failure of venous efferent flow to precisely match arterial afferent flow will yield immediate and dramatic changes in intracranial blood volume and pressure. Interpreting ICP without interrogating its core drivers may be misleading. Multiple clinical conditions and the cerebral effects of altitude and microgravity relate to imbalances in this dynamic rather than ICP per se. This article reviews the Monro-Kellie doctrine, categorises venous outflow limitation conditions, relates physiological mechanisms to clinical conditions and suggests specific management options.
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Affiliation(s)
- Mark H Wilson
- Institute of Pre-Hospital Care, London's Air Ambulance, The Royal London Hospital, Queen Mary College, London, UK
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Guo WY, Bian SZ, Zhang JH, Li QN, Yu J, Chen JF, Tang CF, Rao RS, Yu SY, Jin J, Huang L. Physiological and psychological factors associated with onset of high-altitude headache in Chinese men upon acute high-altitude exposure at 3700 m. Cephalalgia 2016; 37:336-347. [PMID: 27152016 DOI: 10.1177/0333102416646761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aim We aimed to identify clinical characteristics and risk factors associated with onset of high-altitude headache (HAH) after acute exposure at 3700 m. Method In two hours, 163 individuals ascended by plane to 3700 m. Demographic information, physiological and psychological measurements, cognitive function, physical work capacity tests and profile of mood states within one week prior to the departure and within 24 hours after arrival were examined. Results HAH patients featured significantly higher vertebral artery diastolic velocity (Vd), heart rate (HR) and pulmonary artery diameter. HAH was also associated with a more negative mood state, including scores for tension anxiety, depression, hostility, fatigue and confusion, as well as lower vigor (all p values <0.05). Furthermore, negative emotions were positively related to HAH severity. HAH slightly decreased cognitive functioning. HR, Vd, lack of vigor, confusion and self-reported anxiety (all p values <0.05) were independent risk factors for HAH. We have identified three independent baseline predictors for HAH including internal diameter of the left ventricle (LVD), Athens Insomnia Scale (AIS) and confusion score. Conclusions Higher HR, Vd, confusion and self-reported anxiety and insufficient vigor were independent risk factors for HAH. Furthermore, higher baseline LVD, AIS and confusion score are independent predictors of HAH.
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Affiliation(s)
- Wen-Yun Guo
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Shi-Zhu Bian
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Ji-Hang Zhang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Qian-ning Li
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, China
| | - Jie Yu
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Jian-Fei Chen
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Cai-Fa Tang
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, China
| | - Rong-Sheng Rao
- Department of Ultrasonography, Xinqiao Hospital, Third Military Medical University
| | - Shi-Yong Yu
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Jun Jin
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
| | - Lan Huang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, China
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, China
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Kumar G, Chhabra A, Mishra S, Kalam H, Kumar D, Meena R, Ahmad Y, Bhargava K, Prasad DN, Sharma M. H2S Regulates Hypobaric Hypoxia-Induced Early Glio-Vascular Dysfunction and Neuro-Pathophysiological Effects. EBioMedicine 2016; 6:171-189. [PMID: 27211559 PMCID: PMC4856789 DOI: 10.1016/j.ebiom.2016.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 12/20/2022] Open
Abstract
Hypobaric Hypoxia (HH) is an established risk factor for various neuro-physiological perturbations including cognitive impairment. The origin and mechanistic basis of such responses however remain elusive. We here combined systems level analysis with classical neuro-physiological approaches, in a rat model system, to understand pathological responses of brain to HH. Unbiased ‘statistical co-expression networks’ generated utilizing temporal, differential transcriptome signatures of hippocampus—centrally involved in regulating cognition—implicated perturbation of Glio-Vascular homeostasis during early responses to HH, with concurrent modulation of vasomodulatory, hemostatic and proteolytic processes. Further, multiple lines of experimental evidence from ultra-structural, immuno-histological, substrate-zymography and barrier function studies unambiguously supported this proposition. Interestingly, we show a significant lowering of H2S levels in the brain, under chronic HH conditions. This phenomenon functionally impacted hypoxia-induced modulation of cerebral blood flow (hypoxic autoregulation) besides perturbing the strength of functional hyperemia responses. The augmentation of H2S levels, during HH conditions, remarkably preserved Glio-Vascular homeostasis and key neuro-physiological functions (cerebral blood flow, functional hyperemia and spatial memory) besides curtailing HH-induced neuronal apoptosis in hippocampus. Our data thus revealed causal role of H2S during HH-induced early Glio-Vascular dysfunction and consequent cognitive impairment. Glio-Vascular dysfunction temporally precedes Hypobaric Hypoxia (HH) induced neuro-pathological effects. Exposure to HH significantly lowers the levels of H2S in brain. Augmentation of H2S, utilizing its donor, preserves Glio-Vascular homeostasis and curtails HH-induced memory impairment.
The exposure to Hypobaric Hypoxia (HH) environment (such as that encountered by humans at high altitude) culminates in cognitive impairment in an altitude- and duration-dependent manner. The mechanistic basis for such effects, however, remains elusive. Our present study showed that HH-induced neuro-pathological perturbations are temporally preceded by Glio-Vascular dysfunction and are concomitant with lowered levels of gaseous messenger, H2S, in brain. The maintenance of H2S levels (utilizing a specific donor, NaHS) during hypoxia curtailed HH-induced brain-vascular dysfunction and ensuing neuro-pathological effects (on spatial memory). Interestingly, identification of origin of disease in the present study effectively revealed a possible interventional strategy.
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Affiliation(s)
- Gaurav Kumar
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Aastha Chhabra
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Shalini Mishra
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Haroon Kalam
- Immunology Group, International Center for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Dhiraj Kumar
- Immunology Group, International Center for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Ramniwas Meena
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Yasmin Ahmad
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Kalpana Bhargava
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Dipti N Prasad
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India
| | - Manish Sharma
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Delhi 110054, India.
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Han K, Chao AC, Chang FC, Hsu HY, Chung CP, Sheng WY, Chan L, Wu J, Hu HH. Diagnosis of Transverse Sinus Hypoplasia in Magnetic Resonance Venography: New Insights Based on Magnetic Resonance Imaging in Combined Dataset of Venous Outflow Impairment Case-Control Studies: Post Hoc Case-Control Study. Medicine (Baltimore) 2016; 95:e2862. [PMID: 26962781 PMCID: PMC4998862 DOI: 10.1097/md.0000000000002862] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In previous studies of transverse sinus (TS) hypoplasia, discrepancies between TS diameter measured by magnetic resonance venography (MRV) and contrast T1-weighted magnetic resonance (contrast T1) were observed. To investigate these discrepancies, and considering that TS hypoplasia is associated with neurological disorders, we performed a post hoc analysis of prospectively collected data from 3 case-control studies on transient global amnesia (TGA), transient monocular blindness (TMB), and panic disorders while retaining the original inclusion and exclusion criteria. Magnetic resonance (MR) imaging of 131 subjects was reviewed to evaluate TS diameter and the location and degree of venous flow stenosis and obstruction.MRV without contrast revealed that TS hypoplasia was observed in 69 subjects, whom we classified into 2 subgroups according to the concordance with contrast T1 observations: concordance indicated anatomically small TS (30 subjects), and discrepancy indicated that the MRV diagnosis is in fact flow-related and that TS is not anatomically small (39 subjects). The latter subgroup was associated with at least 1 site of venous compression/stenosis in the internal jugular vein (IJV) or the left brachiocephalic vein (BCV) (P < 0.001), which was significantly larger in patients than controls. Compensatory dilatation of contralateral TS diameter was only observed with MRV, not with contrast T1 imaging.The clinical implication of these results is that using MRV only, IJV/BCV compression/stenosis may be misdiagnosed as TS hypoplasia. And contralateral TS have no compensatory dilatation in its diameter in contrast T1 imaging, just compensatory increased flow volume.
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Affiliation(s)
- Ke Han
- From the Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, Jilin, China (KH, JW), Department of Neurology, College of Medicine, Kaohsiung Medical University and Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung (A-CC), Department of Radiology (F-CC), Department of Neurology Veterans General Hospital and National Yang-Ming University (C-PC, W-YS), Department of Neurology, Tungs' Taichung Metro Harbor Hospital and Department of Neurology, School of Medicine, Chung Shan Medical University, Taichung (H-YH), Department of Neurology, Taipei Medical University-Shaung Ho Hospital (LC), and Graduate Institute of Clinical Medicine and Department of Neurology, College of Medicine, Taipei Medical University and Hospital (H-HH), Taipei, Taiwan
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Hoffmann A, Kunze R, Helluy X, Milford D, Heiland S, Bendszus M, Pham M, Marti HH. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb. PLoS One 2016; 11:e0148441. [PMID: 26863147 PMCID: PMC4749302 DOI: 10.1371/journal.pone.0148441] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 01/18/2016] [Indexed: 11/19/2022] Open
Abstract
Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema.
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Affiliation(s)
- Angelika Hoffmann
- Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
- * E-mail: (AH); (HHM)
| | - Reiner Kunze
- Institute of Physiology and Pathophysiology, University of Heidelberg, 69120, Heidelberg, Germany
| | - Xavier Helluy
- Division of Experimental Radiology, Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - David Milford
- Division of Experimental Radiology, Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Sabine Heiland
- Division of Experimental Radiology, Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Mirko Pham
- Department of Neuroradiology, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Hugo H. Marti
- Institute of Physiology and Pathophysiology, University of Heidelberg, 69120, Heidelberg, Germany
- * E-mail: (AH); (HHM)
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Lawley JS, Levine BD, Williams MA, Malm J, Eklund A, Polaner DM, Subudhi AW, Hackett PH, Roach RC. Cerebral spinal fluid dynamics: effect of hypoxia and implications for high-altitude illness. J Appl Physiol (1985) 2016; 120:251-62. [DOI: 10.1152/japplphysiol.00370.2015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/17/2015] [Indexed: 12/24/2022] Open
Abstract
The pathophysiology of acute mountain sickness and high-altitude cerebral edema, the cerebral forms of high-altitude illness, remain uncertain and controversial. Persistently elevated or pathological fluctuations in intracranial pressure are thought to cause symptoms similar to those reported by individuals suffering cerebral forms of high-altitude illness. This review first focuses on the basic physiology of the craniospinal system, including a detailed discussion of the long-term and dynamic regulation of intracranial pressure. Thereafter, we critically examine the available literature, based primarily on invasive pressure monitoring, that suggests intracranial pressure is acutely elevated at altitude due to brain swelling and/or elevated sagittal sinus pressure, but normalizes over time. We hypothesize that fluctuations in intracranial pressure occur around a slightly elevated or normal mean intracranial pressure, in conjunction with oscillations in arterial Po2 and arterial blood pressure. Then these modest fluctuations in intracranial pressure, in concert with direct vascular stretch due to dilatation and/or increased blood pressure transmission, activate the trigeminal vascular system and cause symptoms of acute mountain sickness. Elevated brain water (vasogenic edema) may be due to breakdown of the blood-brain barrier. However, new information suggests cerebral spinal fluid flux into the brain may be an important factor. Regardless of the source (or mechanisms responsible) for the excess brain water, brain swelling occurs, and a “tight fit” brain would be a major risk factor to produce symptoms; activities that produce large changes in brain volume and cause fluctuations in blood pressure are likely contributing factors.
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Affiliation(s)
- Justin S. Lawley
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, Texas
- UT Southwestern Medical Center, Dallas, Texas
| | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, Texas
- UT Southwestern Medical Center, Dallas, Texas
| | - Michael A. Williams
- Sandra and Malcolm Berman Brain & Spine Institute, Dept. of Neurology, Sinai Hospital, Baltimore, Maryland
| | - Jon Malm
- Department of Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - David M. Polaner
- Departments of Anesthesiology and Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado
| | - Andrew W. Subudhi
- Department of Biology, University of Colorado, Colorado Springs, Colorado
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado; and
| | | | - Robert C. Roach
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado; and
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Abstract
The Caudwell Xtreme Everest (CXE) expedition in the spring of 2007 systematically studied 222 healthy volunteers as they ascended from sea level to Everest Base Camp (5300 m). A subgroup of climbing investigators ascended higher on Everest and obtained physiological measurements up to an altitude of 8400 m. The aim of the study was to explore inter-individual variation in response to environmental hypobaric hypoxia in order to understand better the pathophysiology of critically ill patients and other patients in whom hypoxaemia and cellular hypoxia are prevalent. This paper describes the aims, study characteristics, organization and management of the CXE expedition.
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Khademi S, Frye MA, Jeckel KM, Schroeder T, Monnet E, Irwin DC, Cole PA, Bell C, Miller BF, Hamilton KL. Hypoxia mediated pulmonary edema: potential influence of oxidative stress, sympathetic activation and cerebral blood flow. BMC PHYSIOLOGY 2015; 15:4. [PMID: 26449218 PMCID: PMC4599206 DOI: 10.1186/s12899-015-0018-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 10/02/2015] [Indexed: 10/25/2022]
Abstract
BACKGROUND Neurogenic pulmonary edema (NPE) is a non-cardiogenic form of pulmonary edema that can occur consequent to central neurologic insults including stroke, traumatic brain injury, and seizure. NPE is a public health concern due to high morbidity and mortality, yet the mechanism(s) are unknown. We hypothesized that NPE, evoked by cerebral hypoxia in the presence of systemic normoxia, would be accompanied by sympathetic activation, oxidative stress, and compensatory antioxidant mechanisms. METHODS Thirteen Walker hounds were assigned to cerebral hypoxia (SaO2 ~ 55 %) with systemic normoxia (SaO2 ~ 90 %) (CH; n = 6), cerebral and systemic (global) hypoxia (SaO2 ~ 60 %) (GH; n = 4), or cerebral and systemic normoxia (SaO2 ~ 90 %) (CON; n = 3). Femoral venous (CH and CON) perfusate was delivered via cardiopulmonary bypass to the brain and GH was induced by FiO2 = 10 % to maintain the SaO2 at ~60 %. Lung wet to lung dry weight ratios (LWW/LDW) were assessed as an index of pulmonary edema in addition to hemodynamic measurements. Plasma catecholamines were measured as markers of sympathetic nervous system (SNS) activity. Total glutathione, protein carbonyls, and malondialdehyde were assessed as indicators of oxidative stress. Brain and lung compensatory antioxidants were measured with immunoblotting. RESULTS Compared to CON, LWW/LDW and pulmonary artery pressure were greater in CH and GH. Expression of hemeoxygenase-1 in brain was higher in CH compared to GH and CON, despite no group differences in oxidative damage in any tissue. Catecholamines tended to be higher in CH and GH. CONCLUSION Cerebral hypoxia, with systemic normoxia, is not systematically associated with an increase in oxidative stress and compensatory antioxidant enzymes in lung, suggesting oxidative stress did not contribute to NPE in lung. However, increased SNS activity may play a role in the induction of NPE during hypoxia.
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Affiliation(s)
- Shadi Khademi
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA. .,, 3333 Burnet Avenue, Building R, Room 3503, Cincinnati, 45229, OH, USA.
| | - Melinda A Frye
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Kimberly M Jeckel
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Thies Schroeder
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA.
| | - Eric Monnet
- Clinical Sciences, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Dave C Irwin
- Cardiovascular Pulmonary Research, University of Colorado Denver, Anschutz Medical Campus, Denver, CO, 80045, USA.
| | - Patricia A Cole
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Christopher Bell
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.
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Aksoy M, Ince I, Ahıskalıoglu A, Karaca O, Bayar F, Erdem AF. Spinal anaesthesia at low and moderately high altitudes: a comparison of anaesthetic parameters and hemodynamic changes. BMC Anesthesiol 2015; 15:123. [PMID: 26357836 PMCID: PMC4566491 DOI: 10.1186/s12871-015-0104-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 09/07/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypoxemia caused high altitude leads to an increase and variability in CSF volume. The purpose of this prospective study was to detect the differences, if any, between moderately highlanders and lowlanders in terms of anaesthetic parameters under neuroaxial anaesthesia. METHODS Consecutive patients living at moderately high altitude (Erzurum, 1890 m above the sea level) and sea level (Sakarya, 31 m above the sea level) scheduled for elective lower extremity surgery with spinal anaesthesia were enrolled in this study (n = 70, for each group). Same anaesthesia protocol was applied for all patients. Spinal anaesthesia was provided with hyperbaric bupivacaine 0.5 %, 9 mg (1.8 mL) in all patients. Anaesthetic characteristics and hemodynamic parameters of patients were recorded. The findings obtained in two different altitudes were compared using appropriate statistical tests. If data was not normally distributed, comparisons were determined using the Mann-Whitney U-test. Comparisons were determined using the Independent T test when data was normally distributed and Fisher's exact test was used to compare the percentage values. RESULTS Duration of the block procedure (minutes) was significantly shorter at the sea level (14.34 ± 0.88) than at moderate altitude (20.38 ± 1.46) (P < 0.001). Motor block duration (minutes) was higher at the sea level compared to the moderate altitude (310.2 ± 104.2, 200.4 ± 103.2; respectively; P < 0.05). Also, the sensory block time (minutes) was higher at the sea level compared to moderate altitude (200.2 ± 50. minutes vs. 155.2 ± 60.7 min; respectively; P < 0.05). Moderate altitude group had significantly higher MABP values at baseline, during surgery and at postoperative 1(st) and 2nd hours than in the sea level group (P < 0.05, for all). Moderately high altitude group had lower heart rate values at baseline, during surgery and postoperative 1(st) and 2(nd) hours compared with the sea level group (P < 0.05). PDPH was seen more frequently (7.14 vs. 2.85 %; P < 0.05) at moderate altitude. CONCLUSIONS Hemodynamic variations and more anaesthetic requirements following the spinal anaesthesia may be observed at moderately high altitudes compared to the sea level. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry: ACTRN12614000749606 .
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Affiliation(s)
- Mehmet Aksoy
- Department of Anaesthesiology and Reanimation, Faculty of Medicine, Ataturk University, Erzurum, Turkey, 25240.
| | - Ilker Ince
- Department of Anaesthesiology and Reanimation, Faculty of Medicine, Ataturk University, Erzurum, Turkey, 25240.
| | - Ali Ahıskalıoglu
- Department of Anaesthesiology and Reanimation, Faculty of Medicine, Ataturk University, Erzurum, Turkey, 25240.
| | - Omer Karaca
- Department of Anaesthesiology and Reanimation, Ordu State Hospital, Ordu, Turkey.
| | - Fikret Bayar
- Department of Anaesthesiology and Reanimation, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
| | - Ali Fuat Erdem
- Department of Anaesthesiology and Reanimation, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
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Wilson MH, Imray CHE. The cerebral venous system and hypoxia. J Appl Physiol (1985) 2015; 120:244-50. [PMID: 26294747 DOI: 10.1152/japplphysiol.00327.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/13/2015] [Indexed: 01/24/2023] Open
Abstract
Most hypobaric hypoxia studies have focused on oxygen delivery and therefore cerebral blood inflow. Few have studied venous outflow. However, the volume of blood entering and leaving the skull (∼700 ml/min) is considerably greater than cerebrospinal fluid production (0.35 ml/min) or edema formation rates and slight imbalances of in- and outflow have considerable effects on intracranial pressure. This dynamic phenomenon is not necessarily appreciated in the currently taught static "Monro-Kellie" doctrine, which forms the basis of the "Tight-Fit" hypothesis thought to underlie high altitude headache, acute mountain sickness, and high altitude cerebral edema. Investigating both sides of the cerebral circulation was an integral part of the 2007 Xtreme Everest Expedition. The results of the relevant studies performed as part of and subsequent to this expedition are reviewed here. The evidence from recent studies suggests a relative venous outflow insufficiency is an early step in the pathogenesis of high altitude headache. Translation of knowledge gained from high altitude studies is important. Many patients in a critical care environment develop hypoxemia akin to that of high altitude exposure. An inability to drain the hypoxemic induced increase in cerebral blood flow could be an underappreciated regulatory mechanism of intracranial pressure.
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Affiliation(s)
- Mark H Wilson
- The Centre for Altitude, Space and Extreme Environment Medicine, University College London, London, United Kingdom; The Birmingham Medical Research Expeditionary Society, Queen Elizabeth Hospital, Edgbaston, Birmingham, United Kingdom; Imperial Neurotrauma Centre, Imperial College, St Mary's Hospital, London, United Kingdom; Institute of Pre-Hospital Care, London's Air Ambulance, Royal London Hospital, Whitechapel, United Kingdom; and
| | - Christopher H E Imray
- The Centre for Altitude, Space and Extreme Environment Medicine, University College London, London, United Kingdom; The Birmingham Medical Research Expeditionary Society, Queen Elizabeth Hospital, Edgbaston, Birmingham, United Kingdom; Department of Surgery, Warwick Medical School, UHCW NHS Trust, Warwick, United Kingdom
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Swenson ER. Pharmacology of acute mountain sickness: old drugs and newer thinking. J Appl Physiol (1985) 2015; 120:204-15. [PMID: 26294748 DOI: 10.1152/japplphysiol.00443.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/12/2015] [Indexed: 01/09/2023] Open
Abstract
Pharmacotherapy in acute mountain sickness (AMS) for the past half century has largely rested on the use of carbonic anhydrase (CA) inhibitors, such as acetazolamide, and corticosteroids, such as dexamethasone. The benefits of CA inhibitors are thought to arise from their known ventilatory stimulation and resultant greater arterial oxygenation from inhibition of renal CA and generation of a mild metabolic acidosis. The benefits of corticosteroids include their broad-based anti-inflammatory and anti-edemagenic effects. What has emerged from more recent work is the strong likelihood that drugs in both classes act on other pathways and signaling beyond their classical actions to prevent and treat AMS. For the CA inhibitors, these include reduction in aquaporin-mediated transmembrane water transport, anti-oxidant actions, vasodilation, and anti-inflammatory effects. In the case of corticosteroids, these include protection against increases in vascular endothelial and blood-brain barrier permeability, suppression of inflammatory cytokines and reactive oxygen species production, and sympatholysis. The loci of action of both classes of drug include the brain, but may also involve the lung as revealed by benefits that arise with selective administration to the lungs by inhalation. Greater understanding of their pluripotent actions and sites of action in AMS may help guide development of better drugs with more selective action and fewer side effects.
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Affiliation(s)
- Erik R Swenson
- Veterans Affairs Puget Sound Health Care System, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Seattle
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Cerebral Hemodynamics at Altitude: Effects of Hyperventilation and Acclimatization on Cerebral Blood Flow and Oxygenation. Wilderness Environ Med 2015; 26:133-41. [DOI: 10.1016/j.wem.2014.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 07/15/2014] [Accepted: 10/08/2014] [Indexed: 11/22/2022]
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Bian SZ, Jin J, Li QN, Yu J, Tang CF, Rao RS, Yu SY, Zhao XH, Qin J, Huang L. Hemodynamic characteristics of high-altitude headache following acute high altitude exposure at 3700 m in young Chinese men. J Headache Pain 2015; 16:527. [PMID: 25968101 PMCID: PMC4431987 DOI: 10.1186/s10194-015-0527-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/01/2015] [Indexed: 12/04/2022] Open
Abstract
Background This study aimed to identify the systemic and cerebral hemodynamic characteristics and their roles in high-altitude headache (HAH) among young Chinese men following acute exposure. Methods The subjects (n = 385) were recruited in June and July of 2012. They completed case report form questionnaires, as well as heart rate (HR), blood pressure, echocardiogram and transcranial Doppler examinations at 3700 m following a two-hour plane flight. A subgroup of 129 participants was examined at two altitudes (500 and 3700 m). Results HAH was characterized by increased HR and cardiac output (CO) and lower saturation pulse oxygen (SpO2) (all p < 0.05). The change in tricuspid regurgitation was also different between the HAH positive (HAH+) and HAH negative (HAH-) subjects. Furthermore, the HAH+ subjects exhibited faster mean (Vm), systolic (Vs) and diastolic (Vd) velocities in the basilar artery (BA; all p < 0.05) and a faster Vd ( 25.96 ± 4.97 cm/s vs. 24.76 ± 4.76 cm/s, p = 0.045) in the left vertebral artery (VA). The bilateral VA asymmetry was also significantly different between the two groups. The pulsatility index (PI) and resistance index (RI) of left VA were lower in the HAH subjects (p < 0.05) and were negatively correlated with HAH (p < 0.05). Baseline CO and Vm in left VA (or right MCA in different regressions) were independent predictors for HAH, whereas CO/HR and ΔVd (Vd difference between bilateral VAs) were independent risk factors for HAH at 3700 m. Conclusions HAH was characterized, in part, by increased systemic hemodynamics and posterior cerebral circulation, which was reflected by the BA and left VA velocities, and lower arterial resistance and compliance. Furthermore, baseline CO and Vm in left VA or right MCA at sea level were independent predictors for HAH, whilst bilateral VA asymmetry may contribute to the development of HAH at high altitude. Electronic supplementary material The online version of this article (doi:10.1186/s10194-015-0527-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shi-Zhu Bian
- Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Street, Chongqing, 400037, China,
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