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Jing L, Wu N, Zhang J, Da Q, Ma H. Protective effect of 5,6,7,8-Tetrahydroxyflavone on high altitude cerebral edema in rats. Eur J Pharmacol 2022; 928:175121. [PMID: 35777443 DOI: 10.1016/j.ejphar.2022.175121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 11/03/2022]
Abstract
High altitude cerebral edema (HACE) is a potentially life-threatening disease encountered at high altitudes. However, effective methods for HACE prophylaxis are limited. Convincing evidence confirms that oxidative stress induced by hypobaric hypoxia (HH) is one of the main factors that account for the development of HACE. 5,6,7,8-Tetrahydroxyflavone (THF), a flavone with four consecutive OH groups in ring A, exhibited excellent antioxidant activity in vitro and could attenuate HH induced injury in vivo. The aim of this study was to investigate the protective effect of THF against HACE and its underlying mechanisms. THF administration significantly suppressed HH induced oxidative stress by reducing the formation of hydrogen peroxide and malondialdehyde, by increasing the levels of glutathione and superoxide dismutase in brain tissue. Simultaneously, THF administration inhibited inflammatory responses by decreasing the levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in serum and brain tissue. In addition, THF administration mitigated the energy metabolism disorder induced by HACE as evidenced by decreased levels of lactic acid, lactate dehydrogenase and pyruvate kinase as well as increased ATP levels and ATPase activities. Furthermore, THF administration decreased the expression of matrix metalloproteinase-9, aquaporin 4, hypoxia-inducible factor-1α and vascular endothelial growth factor, which attenuated blood-brain barrier (BBB) disruption and brain edema. Additionally, THF administration improved HACE induced cognitive dysfunction. These results show that THF is a promising agent in the prevention and treatment of HACE.
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Affiliation(s)
- Linlin Jing
- Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China; Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, Gansu, 730050, China.
| | - Ningzi Wu
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, Gansu, 730050, China
| | - Jie Zhang
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, Gansu, 730050, China
| | - Qingyue Da
- Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China; Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, Gansu, 730050, China
| | - Huiping Ma
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, Gansu, 730050, China.
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Du D, Zhang Y, Zhu C, Chen H, Sun J. Metabolic Regulation of Hypoxia-Inducible Factors in Hypothalamus. Front Endocrinol (Lausanne) 2021; 12:650284. [PMID: 33763034 PMCID: PMC7984363 DOI: 10.3389/fendo.2021.650284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 01/29/2021] [Indexed: 12/30/2022] Open
Abstract
The earliest hypoxia-inducible factor (HIF) function was to respond to hypoxia or hypoxic conditions as a transcription factor. Recent studies have expanded our understanding of HIF, and a large amount of evidence indicates that HIF has an essential effect on central regulation of metabolism. The central nervous system's response to glucose, inflammation, and hormones' main influence on systemic metabolism are all regulated by HIF to varying degrees. In the hypothalamus, HIF mostly plays a role in inhibiting energy uptake and promoting energy expenditure, which depends not only on the single effect of HIF or a single part of the hypothalamus. In this paper, we summarize the recent progress in the central regulation of metabolism, describe in detail the role of HIF in various functions of the hypothalamus and related molecular mechanisms, and reveal that HIF is deeply involved in hypothalamic-mediated metabolic regulation.
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Affiliation(s)
- Dan Du
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yugang Zhang
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Canjun Zhu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangzhou, China
- *Correspondence: Jia Sun, ; Hong Chen, ; Canjun Zhu,
| | - Hong Chen
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Correspondence: Jia Sun, ; Hong Chen, ; Canjun Zhu,
| | - Jia Sun
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Correspondence: Jia Sun, ; Hong Chen, ; Canjun Zhu,
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Jing L, Wu N, He L, Shao J, Ma H. Establishment of an experimental rat model of high altitude cerebral edema by hypobaric hypoxia combined with temperature fluctuation. Brain Res Bull 2020; 165:253-262. [PMID: 33141074 DOI: 10.1016/j.brainresbull.2020.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 12/11/2022]
Abstract
High altitude cerebral edema (HACE) is a kind of life threat disease encountered at high altitude, but the precise pathogenesis of it is far more understood. Hypobaic hypoxia (HH) and cold are conditions characteristic of high altitude environment. HH is always considered as the central causative factor for the development of HACE, but the effect of cold stress on HACE has been rarely investigated. The purpose of this study was to investigate the potential role of cold stress in the development of HACE and establish a stable experimental animal model. Male SPF Wistar rats were randomly divided into five groups for this experiment, control group (altitude, 1400 m, temperature, 25 ℃), NC + 2 ℃ group (altitude, 1400 m, temperature, 2 ℃), HH group (altitude, 6000 m, temperature, 25 ℃), HH+2 ℃ group (altitude, 6000 m, temperature, 2 ℃) and HH + 12/2 ℃ (altitude, 6000 m, temperature, 12 ℃/2 ℃ light/dark cycle). After exposure for 72 h, the blood and brain tissues were collected. Brain water content (BWC) and Evans Blue dye extravasation were used to assess the brain edema and blood-brain barrier (BBB) permeability, respectively. The levels of pro-inflammatory cytokines in serum were assessed via enzyme-linked immunosorbent assay. Oxidative stress markers and ATPase activity were determined using commercial kits. Western blotting was used to detect the expression of related proteins. Compared to control, HH+2 ℃ could significantly increase the BWC and BBB permeability, and these changes were further exacerbated by HH + 12/2 ℃. Furthermore, HH+2 ℃ and HH + 12/2 ℃ markedly increased the levels of H2O2 and MDA, restrained SOD and GSH levels and decreased Na+/K+-ATPase activitie compared with the control group. In addition, HH+2 ℃ and HH + 12/2 ℃ enhanced the levels of pro-inflammatory cytokines IL-1β, TNF-α and IL-6 in serum and significantly increased the expression of VEGF in brain compared with the control group, but only HH + 12/2 ℃ could increase the expression of AQP4. However, compared with control group, no significant differences in these parameters were observed in HH and NC+2 ℃groups. These results demonstrated that HH or cold stress alone did not successfully induce brain damage, while HH+2 ℃ could induce the onset of HACE via provoking injury caused by HH. HH + 12/2 ℃ was more obvious and efficient. Collectively, we firstly suggest that cold stress may promote the formation of HACE by aggravating the brain injury induced by HH exposure and supply an effective and reliable experimental rat model of HACE via HH combined with temperature fluctuation.
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Affiliation(s)
- Linlin Jing
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force, Lanzhou, Gansu, 730050, People's Republic of China
| | - Ningzi Wu
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force, Lanzhou, Gansu, 730050, People's Republic of China
| | - Lei He
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force, Lanzhou, Gansu, 730050, People's Republic of China
| | - Jin Shao
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force, Lanzhou, Gansu, 730050, People's Republic of China
| | - Huiping Ma
- Department of Pharmacy, The 940th Hospital of Joint Logistics Support Force, Lanzhou, Gansu, 730050, People's Republic of China.
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4
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Pan Y, Zhang Y, Yuan J, Ma X, Zhao Y, Li Y, Li F, Gong X, Zhao J, Tang H, Wang J. Tetrahydrocurcumin mitigates acute hypobaric hypoxia-induced cerebral oedema and inflammation through the NF-κB/VEGF/MMP-9 pathway. Phytother Res 2020; 34:2963-2977. [PMID: 32573860 DOI: 10.1002/ptr.6724] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/07/2020] [Accepted: 04/23/2020] [Indexed: 12/23/2022]
Abstract
High-altitude cerebral oedema (HACE) is a potentially fatal manifestation of high-altitude sickness and is caused partly by inflammation and the blood-brain barrier disruption. Tetrahydrocurcumin (THC) has been reported to exert effective antioxidative and anti-inflammatory effects; This study sought to elucidate the underlying mechanism of THC in mitigating HACE using a mouse model. Our results revealed that prophylactic administration of THC (40 mg/kg) for 3 days significantly alleviated the increase in brain water content (BWC), interleukin-1β (IL-1β) and TNF-α levels caused by acute hypobaric hypoxia (AHH). Additionally, superoxide dismutase (SOD) activity was increased by THC to enhance the ability to resist hypoxia. Histological and ultrastructural analysis of the cerebrum revealed that THC administration mitigated AHH-induced pericellular oedema and reduced the perivascular space, resulting in the simultaneous remission of oedema and protection of mitochondria in the cerebrum. In vitro, astrocytes exposed to hypoxia (4% O2 ) for 24 hr exhibited and increase in IL-1β expression followed by an increase in vascular endothelial growth factor (VEGF) levels. Furthermore, THC administration remarkably downregulated VEGF, matrix metallopeptidase-9 (MMP-9), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, both in vivo and in vitro. Our data highlight the potential prophylactic activity of THC in HACE, it effectively mitigates AHH-induced cerebral oedema and inflammation is associated with the inhibition of the NF-κB/ VEGF/MMP-9 pathways.
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Affiliation(s)
- Yang Pan
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China
| | - Yan Zhang
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Jiani Yuan
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China
| | - Xuexinyu Ma
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Yani Zhao
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Yao Li
- Faculty of Life Science & Medicine, Northwest University, Xi'an, China
| | - Fei Li
- Department of Pharmacy, Xijing Hospital, The Air Force Medical University, Xi'an, China
| | - Xiaoli Gong
- Center for translational Chinese Medicine, Sichuan Academy of Chinese Medicine Sciences, Chengdu, China
| | - Junning Zhao
- Center for translational Chinese Medicine, Sichuan Academy of Chinese Medicine Sciences, Chengdu, China
| | - Haifeng Tang
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China
| | - Jianbo Wang
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China.,Center for translational Chinese Medicine, Sichuan Academy of Chinese Medicine Sciences, Chengdu, China
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Kutty RK, Sreemathyamma SB, Sivanandapanicker JL, Asher P, Peethambaran A. Flying with Colloid Cyst: A Cautionary Note. World Neurosurg 2020; 138:84-88. [PMID: 32001391 DOI: 10.1016/j.wneu.2020.01.124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Colloid cysts are benign and rare tumors of the brain. The growth rates of these tumors are unpredictable. These cysts can increase in size and obstruct the cerebrospinal fluid pathways producing obstructive hydrocephalus. Consequently, this can manifest as acute severe headaches followed by deterioration in consciousness, or even sudden death in patients. Such remarkable episodes occurring in patients during air travel have been reported sparsely in the literature. CASE DESCRIPTION In this report, we narrate the ordeal of a patient who had severe headache followed by loss of consciousness during his air travel. After his arrival, he was taken to a referral center where the diagnosis of a colloid cyst obstructing the cerebrospinal fluid pathway resulting in acute obstructive hydrocephalus was revealed. We analyze the physiologic effects of cabin pressure and high altitude on the intracranial pressure and present a brief review of the literature. CONCLUSIONS Changes in cabin pressure during flight may play a role in worsening of intracranial pressure in patients with colloid cyst with marginal brain compliance.
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Affiliation(s)
- Raja K Kutty
- Department of Neurosurgery, Government Medical College, Thiruvananthapuram, Kerala, India.
| | | | | | - Prasanth Asher
- Department of Neurosurgery, Government Medical College, Thiruvananthapuram, Kerala, India
| | - Anilkumar Peethambaran
- Department of Neurosurgery, Government Medical College, Thiruvananthapuram, Kerala, India
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Whitehouse LM, Manzon RG. Hypoxia alters the expression of hif-1a mRNA and downstream HIF-1 response genes in embryonic and larval lake whitefish (Coregonus clupeaformis). Comp Biochem Physiol A Mol Integr Physiol 2019; 230:81-90. [PMID: 30659950 DOI: 10.1016/j.cbpa.2019.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 12/27/2018] [Accepted: 01/06/2019] [Indexed: 12/12/2022]
Abstract
Lake whitefish (Coregonus clupeaformis) embryos and larvae were exposed to hypoxia at different developmental ages to determine when the cellular response to hypoxia could be initiated. mRNA levels of hypoxia-inducible factor 1α (hif-1α), hsp70, and several HIF-1 target genes were quantified in embryos at 21, 38, 63, 83- and 103-days post fertilisation (dpf) and in larvae at 1, 2, 3- and 4-weeks post hatch (wph) following a 6-hour hypoxia exposure. hsp70 mRNA levels were increased in response to hypoxia at all embryonic ages. By comparison, the first observed change in hif-1α mRNA in response to hypoxia was at 38 dpf, where it was down-regulated from high basal levels, with this response persisting through to 83 dpf. Interestingly, this decrease in hif-1α mRNA coincided with increases in the mRNA levels of the HIF-1 target genes: vegfa (vascular endothelial growth factor A), igfbp1 (insulin-like growth factor binding protein 1), ldha (lactate dehydrogenase a), gapdh (glyceraldehyde-3-phosphate dehydrogenase) and epo (erythropoietin) at select ages. Collectively, this suggests a possible HIF-1-mediated response to hypoxia despite a decrease in hif-1α mRNA. Coinciding with a decrease in basal levels, increases in hif-1α were measured in response to hypoxia at 103 dpf and in larval fish at 1, 2 and 3 wph but there were no consistent increases in HIF-1 target genes at these ages. Overall, our findings indicate that lake whitefish can mount a response to hypoxia early in embryogenesis which may mitigate some of the damaging effects of exposure to low oxygen levels at these critical life history stages.
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Affiliation(s)
- Lindy M Whitehouse
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Richard G Manzon
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada.
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Jones JG. The Hypoxia Hilton: Recollections of a Visit, with a Postscript by JW Severinghaus on Mechanisms of Acute Mountain Sickness. J R Soc Med 2017. [DOI: 10.1177/014107680209501208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- J G Jones
- Woodlands, Rufforth, York YO2 3QF, UK
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8
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Jain A, Kratimenos P, Koutroulis I, Jain A, Buddhavarapu A, Ara J. Effect of Intranasally Delivered rh-VEGF165 on Angiogenesis Following Cerebral Hypoxia-Ischemia in the Cerebral Cortex of Newborn Piglets. Int J Mol Sci 2017; 18:ijms18112356. [PMID: 29112164 PMCID: PMC5713325 DOI: 10.3390/ijms18112356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/28/2017] [Accepted: 11/03/2017] [Indexed: 11/22/2022] Open
Abstract
Background: Vascular endothelial growth factor (VEGF) stimulates vascular genesis and angiogenesis. Cerebral Hypoxia-Ischemia (HI) leads to the reduction of vasculature in the cerebral cortex of newborn piglets. Objective: The present study tests the hypothesis that post-hypoxia intranasal administration of recombinant human VEGF165 (rh-VEGF165) for 3 days increases the vascular density in the cerebral cortex of newborn piglets without promoting neovascularization. Design/Methods: Ventilated newborn piglets were divided into three groups (n = 5/group): normoxic (Nx), hypoxic-ischemic (HI), and HI treated with intranasal rh-VEGF165rh-VEGF165 (HI-VEGF). HI piglets were exposed to HI (0.05 FiO2) for 30 min. Recombinant h-VEGF165 (100 ng/kg) was administered 15 min after HI and then once daily for 3 days. The animals were perfused transcardially and coronal brains sections were processed for Isolectin, Hoechst, and ki-67 cell proliferation marker staining. To assess the vascular density, 30–35 fields per animal section were manually counted using image J software. Results: The vascular density (vessels/mm2) was 42.0 ± 8.0 in the Nx group, 26.4 ± 4.8 (p < 0.05 vs. Nx) in the HI group, and 46.0 ± 11.9 (p < 0.05 vs. HI) in the HI-VEGF group. When stained for newly formed vessels, via Ki-67 staining, the vascular density was 5.4 ± 3.6 in the Nx group (p < 0.05 vs. HI), 10.2 ± 2.1 in the HI group, and 10.9 ± 2.9 in the HI-VEGF group (p = 0.72 vs. HI). HI resulted in a decrease in vascular density. Intranasal rh-VEGF165rh-VEGF165 resulted in the attenuation of the HI-induced decrease in vascular density. However, rh-VEGF165 did not result in the formation of new vascularity, as evident by ki-67 staining. Conclusions: Intranasal rh-VEGF165 may prevent the HI-induced decrease in the vascular density of the brain and could serve as a promising adjuvant therapy for hypoxic-ischemic encephalopathy (HIE).
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Affiliation(s)
- Amit Jain
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA.
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sanford Children's Hospital, Sioux Falls, SD 57105, USA.
| | - Panagiotis Kratimenos
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA.
- Department of Pediatrics, Division of Neonatology, Children's National Medical Center, School of Medicine and Health Sciences, George Washington University, Washington, DC 20010, USA.
| | - Ioannis Koutroulis
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA.
- Department of Pediatrics and Emergency Medicine, Children's National Medical Center, School of Medicine and Health Sciences, George Washington University, Washington, DC 20010, USA.
| | - Amishi Jain
- College of Pharmacy and Allied Health Professions, South Dakota State University, Brookings, SD 57007, USA.
| | - Amulya Buddhavarapu
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA.
- Department of Pediatrics, Driscoll Children's Hospital, Texas A&M College of Medicine, Corpus Christi, TX 77807, USA.
| | - Jahan Ara
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA.
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9
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Kanaan NC, Peterson AL, Pun M, Holck PS, Starling J, Basyal B, Freeman TF, Gehner JR, Keyes L, Levin DR, O'Leary CJ, Stuart KE, Thapa GB, Tiwari A, Velgersdyk JL, Zafren K, Basnyat B. Prophylactic Acetaminophen or Ibuprofen Results in Equivalent Acute Mountain Sickness Incidence at High Altitude: A Prospective Randomized Trial. Wilderness Environ Med 2017; 28:72-78. [PMID: 28479001 DOI: 10.1016/j.wem.2016.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/15/2016] [Accepted: 12/30/2016] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Recent trials have demonstrated the usefulness of ibuprofen in the prevention of acute mountain sickness (AMS), yet the proposed anti-inflammatory mechanism remains unconfirmed. Acetaminophen and ibuprofen were tested for AMS prevention. We hypothesized that a greater clinical effect would be seen from ibuprofen due to its anti-inflammatory effects compared with acetaminophen's mechanism of possible symptom reduction by predominantly mediating nociception in the brain. METHODS A double-blind, randomized trial was conducted testing acetaminophen vs ibuprofen for the prevention of AMS. A total of 332 non-Nepali participants were recruited at Pheriche (4371 m) and Dingboche (4410 m) on the Everest Base Camp trek. The participants were randomized to either acetaminophen 1000 mg or ibuprofen 600 mg 3 times a day until they reached Lobuche (4940 m), where they were reassessed. The primary outcome was AMS incidence measured by the Lake Louise Questionnaire score. RESULTS Data from 225 participants who met inclusion criteria were analyzed. Twenty-five participants (22.1%) in the acetaminophen group and 18 (16.1%) in the ibuprofen group developed AMS (P = .235). The combined AMS incidence was 19.1% (43 participants), 14 percentage points lower than the expected AMS incidence of untreated trekkers in prior studies at this location, suggesting that both interventions reduced the incidence of AMS. CONCLUSIONS We found little evidence of any difference between acetaminophen and ibuprofen groups in AMS incidence. This suggests that AMS prevention may be multifactorial, affected by anti-inflammatory inhibition of the arachidonic-acid pathway as well as other analgesic mechanisms that mediate nociception. Additional study is needed.
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Affiliation(s)
- Nicholas C Kanaan
- Division of Emergency Medicine, University of Utah, (Drs Kanaan and Peterson)
| | - Alicia L Peterson
- Division of Emergency Medicine, University of Utah, (Drs Kanaan and Peterson)
| | - Matiram Pun
- Institute of Medicine, Maharajgunj, Kathmandu, Nepal (Drs Pun, Basyal, Thapa, and Tiwari)
| | - Peter S Holck
- the Emergency Medicine Residency, Virginia Tech Carilion (Dr Gehner)
| | | | - Bikash Basyal
- Institute of Medicine, Maharajgunj, Kathmandu, Nepal (Drs Pun, Basyal, Thapa, and Tiwari)
| | | | - Jessica R Gehner
- Department of Emergency Medicine, Augusta University, GA (Dr Freeman)
| | - Linda Keyes
- Department of Emergency Medicine, University of Colorado, Aurora, CO (Dr Keyes)
| | - Dana R Levin
- Department of Aerospace Medicine, University of Texas Medical Branch (Dr Levin)
| | - Catherine J O'Leary
- Department of Emergency Medicine, Thomas Jefferson University Hospital (Dr O'Leary)
| | - Katherine E Stuart
- Department of Emergency Medicine, Queen's University, Kingston, ON, Canada (Dr Stuart)
| | - Ghan B Thapa
- Institute of Medicine, Maharajgunj, Kathmandu, Nepal (Drs Pun, Basyal, Thapa, and Tiwari)
| | - Aditya Tiwari
- Institute of Medicine, Maharajgunj, Kathmandu, Nepal (Drs Pun, Basyal, Thapa, and Tiwari)
| | - Jared L Velgersdyk
- Department of Internal Medicine, University of North Dakota (Dr Velgersdyk); Department of Emergency Medicine, Stanford University Medical Center, Stanford, CA
| | - Ken Zafren
- Himalayan Rescue Association (Dr Zafren); Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Buddha Basnyat
- the Himalayan Rescue Association and the Centre for Tropical Medicine and Global Health, University of Oxford, UK (Dr Basnyat).
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10
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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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Berger MM, Macholz F, Mairbäurl H, Bärtsch P. Remote ischemic preconditioning for prevention of high-altitude diseases: fact or fiction? J Appl Physiol (1985) 2015; 119:1143-51. [PMID: 26089545 DOI: 10.1152/japplphysiol.00156.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/17/2015] [Indexed: 01/14/2023] Open
Abstract
Preconditioning refers to exposure to brief episodes of potentially adverse stimuli and protects against injury during subsequent exposures. This was first described in the heart, where episodes of ischemia/reperfusion render the myocardium resistant to subsequent ischemic injury, which is likely caused by reactive oxygen species (ROS) and proinflammatory processes. Protection of the heart was also found when preconditioning was performed in an organ different from the target, which is called remote ischemic preconditioning (RIPC). The mechanisms causing protection seem to include stimulation of nitric oxide (NO) synthase, increase in antioxidant enzymes, and downregulation of proinflammatory cytokines. These pathways are also thought to play a role in high-altitude diseases: high-altitude pulmonary edema (HAPE) is associated with decreased bioavailability of NO and increased generation of ROS, whereas mechanisms causing acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) seem to involve cytotoxic effects by ROS and inflammation. Based on these apparent similarities between ischemic damage and AMS, HACE, and HAPE, it is reasonable to assume that RIPC might be protective and improve altitude tolerance. In studies addressing high-altitude/hypoxia tolerance, RIPC has been shown to decrease pulmonary arterial systolic pressure in normobaric hypoxia (13% O2) and at high altitude (4,342 m). Our own results indicate that RIPC transiently decreases the severity of AMS at 12% O2. Thus preliminary studies show some benefit, but clearly, further experiments to establish the efficacy and potential mechanism of RIPC are needed.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria; Department of Anesthesiology, University of Heidelberg, Heidelberg, Germany;
| | - Franziska Macholz
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Heimo Mairbäurl
- Department of Internal Medicine VII, Division of Sports Medicine, University of Heidelberg, Heidelberg, Germany; and Translational Lung Research Center Heidelberg, German Center for Lung Research, Heidelberg, Germany
| | - Peter Bärtsch
- Department of Internal Medicine VII, Division of Sports Medicine, University of Heidelberg, Heidelberg, Germany; and
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13
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Update on High Altitude Cerebral Edema Including Recent Work on the Eye. High Alt Med Biol 2014; 15:112-22. [DOI: 10.1089/ham.2013.1142] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Natsume T, Iwatsuki K, Nishizuka T, Arai T, Yamamoto M, Hirata H. Prostaglandin E1 alleviates neuropathic pain and neural dysfunction from entrapment neuropathy associated with diabetes mellitus. Microsurgery 2014; 34:568-75. [DOI: 10.1002/micr.22281] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 05/06/2014] [Accepted: 05/12/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Tadahiro Natsume
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
| | - Katsuyuki Iwatsuki
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
| | - Takanobu Nishizuka
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
| | - Tetsuya Arai
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
| | - Michiro Yamamoto
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
| | - Hitoshi Hirata
- Department of Hand Surgery; Nagoya University Graduate School of Medicine; Showa-Ku Nagoya-Shi Japan
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No changes in cerebellar microvessel length density in sudden infant death syndrome: implications for pathogenetic mechanisms. J Neuropathol Exp Neurol 2014; 73:312-23. [PMID: 24607967 DOI: 10.1097/nen.0000000000000055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sudden infant death syndrome (SIDS) is the leading cause of mortality in infants younger than 1 year in developed countries, but its primary cause remains unknown. Some studies suggest that there may be hypoxia in the cerebellum in SIDS subjects, but mean total Purkinje cell numbers in SIDS versus controls was recently found not to be different. Probably the best marker for chronic hypoxia in a brain region is the microvessel length per unit volume of tissue, that is, the microvessel length density (MLD). Here, we investigated MLDs using a rigorous design-based stereologic approach in all cell layers and white matter in postmortem cerebella from 9 SIDS cases who died between ages 2 and 10 months and from 14 control children, 9 of which were age- and sex- matched to the SIDS cases. We found no differences either in mean MLDs in the cerebellar layers between the SIDS cases and the controls or between controls with a low likelihood of hypoxia and those with a higher likelihood of hypoxia. Immunohistochemical detection of the astrocytosis marker glial fibrillary acidic protein showed no differences between the SIDS and the matched control cases. These data indicate that there is no association of chronic hypoxia in the cerebellum with SIDS.
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Zou YY, Kan EM, Cao Q, Lu J, Ling EA. Combustion smoke-induced inflammation in the cerebellum and hippocampus of adult rats. Neuropathol Appl Neurobiol 2014; 39:531-52. [PMID: 23106634 DOI: 10.1111/nan.12001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/23/2012] [Indexed: 12/12/2022]
Abstract
AIMS The effect of combustion smoke inhalation on the respiratory system is widely reported but its effects on the central nervous system remain unclear. Here, we aimed to determine the effects of smoke inhalation on the cerebellum and hippocampus which are areas vulnerable to hypoxia injury. METHODS Adult male Sprague-Dawley rats were subjected to combustion smoke inhalation and sacrificed at 0.5, 3, 24 and 72 h after exposure. The cerebellum and hippocampus were subjected to Western analysis for VEGF, iNOS, eNOS, nNOS and AQP4 expression; ELISA analysis for cytokine and chemokine levels; and immunohistochemistry for GFAP/AQP4, RECA-1/RITC and TUNEL. Aminoguanidine (AG) was administered to determine the effects of iNOS after smoke inhalation. RESULTS Both the cerebellum and hippocampus showed a significant increase in VEGF, iNOS, eNOS, nNOS and AQP4 expression with corresponding increases in inflammatory cytokines and chemokines and increased AQP4 expression and RITC permeability after smoke exposure. AG was able to decrease the expression of iNOS, followed by VEGF, eNOS, nNOS, RITC and AQP4 after smoke exposure. There was also a significant increase in TUNEL+ cells in the cerebellum and hippocampus which were not significantly reduced by AG. Beam walk test revealed immediate deficits after smoke inhalation which was attenuated with AG. CONCLUSION The findings suggest that iNOS plays a major role in the central nervous system inflammatory pathophysiology after smoke inhalation exposure with concomitant increase in proinflammatory molecules, vascular permeability and oedema, for which the cerebellum appears to be more vulnerable to smoke exposure than the hippocampus.
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Affiliation(s)
- Y-Y Zou
- Department of Pathology, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, China
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Severinghaus JW. Career perspective: John W. Severinghaus. EXTREME PHYSIOLOGY & MEDICINE 2013; 2:29. [PMID: 24192065 PMCID: PMC3850914 DOI: 10.1186/2046-7648-2-29] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 09/12/2013] [Indexed: 11/27/2022]
Abstract
After training in physics during World War II, I spent 2 years designing radar at Massachusetts Institute of Technology and then switched to biophysics. After medical school and a residency, I was doctor drafted to National Institutes of Health where I studied blood gas transport in hypothermia and developed the carbon dioxide electrode and the blood gas analyzer (pH, partial pressure of O2, and partial pressure of CO2). I joined the University of California San Francisco in 1958 in a new anesthesia department and new Cardiovascular Research Institute. My research aims were anesthesia patient monitoring, respiratory physiology, blood gas transport, and high-altitude acclimatization and pathology.
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Bouleti C, Mathivet T, Coqueran B, Serfaty JM, Lesage M, Berland E, Ardidie-Robouant C, Kauffenstein G, Henrion D, Lapergue B, Mazighi M, Duyckaerts C, Thurston G, Valenzuela DM, Murphy AJ, Yancopoulos GD, Monnot C, Margaill I, Germain S. Protective effects of angiopoietin-like 4 on cerebrovascular and functional damages in ischaemic stroke. Eur Heart J 2013; 34:3657-68. [DOI: 10.1093/eurheartj/eht153] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Schommer K, Wiesegart N, Dehnert C, Mairbäurl H, Bärtsch P. No correlation between plasma levels of vascular endothelial growth factor or its soluble receptor and acute mountain sickness. High Alt Med Biol 2012; 12:323-7. [PMID: 22206557 DOI: 10.1089/ham.2011.1020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Increased plasma levels of vascular endothelial growth factor (VEGF) due to lower levels of its soluble receptor (sFlt-1) had been suggested to cause vasogenic brain edema and thereby to cause the symptoms of acute mountain sickness (AMS). We tested this hypothesis after active ascent to high altitude. Plasma was collected from 31 subjects at low altitude (100 m) before (LA1) and after (LA2) 4 weeks of aerobic exercise training in normobaric hypoxia or normoxia, and one night after ascent to high altitude (4559 m). Training modalities (hypoxia or normoxia) did not influence VEGF- and sFlt-1-levels. Therefore, data of both training groups were analyzed together. After one night at 4559 m, 18 subjects had AMS (AMS+), 13 had no AMS (AMS-). In AMS+ and AMS-, VEGF was 110 ± 75 (SD) pg/ml vs. 104 ± 82 (p = 0.74) at LA1, 63 ± 40 vs. 73 ± 50 (p = 0.54) at LA2, and 88 ± 62 vs. 104 ± 81 (p = 0.54) at 4559 m, respectively. Corresponding values for sFlt-1 in AMS+ and AMS- were 81 pg/ml ± 13.1 vs. 82 ± 17 (p = 0.97), 79 ± 11 vs. 80 ± 16 (p = 0.92) and 139 ± 28 vs. 135 ± 31 (p = 0.70), respectively. Absolute values or changes of VEGF were not correlated and those of sFlt-1 slightly correlated with AMS scores. These data provide no evidence for a role of plasma VEGF and sFlt-1 in the pathophysiology of AMS. They do, however, not exclude paracrine effects of VEGF in the brain.
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Affiliation(s)
- Kai Schommer
- Department of Internal Medicine, Division VII Sports Medicine, Medical Clinic, University Hospital Heidelberg, Heidelberg, Germany.
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20
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Abstract
Hypobaric hypoxia is associated with an increase in erythropoesis and an increased thrombotic risk. This is true of long haul air travel, mountaineering expeditions and longer stays at altitude. Studies looking at clotting on mountaineering expeditions are further complicated by the effects of exercise, plasma volume changes and the catecholamine response to hypoxia. This review examines the evidence for changes in clotting factors and functional clotting at altitude and considers the implications of altitude travel for those with pre-existing medical conditions.
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Affiliation(s)
- K Wheatley
- ST3 in Infectious Diseases, Chelsea and Westminster Hospital, Fulham Road, London
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21
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MacInnis MJ, Koehle MS, Rupert JL. Evidence for a genetic basis for altitude illness: 2010 update. High Alt Med Biol 2011; 11:349-68. [PMID: 21190504 DOI: 10.1089/ham.2010.1030] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Altitude illness refers to a group of environmentally mediated pathophysiologies. Many people will suffer acute mountain sickness shortly after rapidly ascending to a moderately hypoxic environment, and an unfortunate few will develop potentially fatal conditions such as high altitude pulmonary edema or high altitude cerebral edema. Some individuals seem to be predisposed to developing altitude illness, suggesting an innate contribution to susceptibility. The implication that there are altitude-sensitive and altitude-tolerant individuals has stimulated much research into the contribution of a genetic background to the efficacy of altitude acclimatization. Although the effect of altitude attained and rate of ascent on the etiology of altitude illness is well known, there are only tantalizing, but rapidly accumulating, clues to the genes that may be involved. In 2006, we reviewed what was then known about the genetics of altitude illness. This article updates that review and attempts to tabulate all the available genetic data pertaining to these conditions. To date, 58 genes have been investigated for a role in altitude illness. Of these, 17 have shown some association with the susceptibility to, or the severity of, these conditions, although in many cases the effect size is small or variable. Caution is recommended when evaluating the genes for which no association was detected, because a number of the investigations reviewed in this article were insufficiently powered to detect small effects. No study has demonstrated a clear-cut altitude illness gene, but the accumulating data are consistent with a polygenic condition with a strong environmental component. The genes that have shown an association affect a variety of biological pathways, suggesting that either multiple systems are involved in altitude pathophysiology or that gene-gene interactions play a role. Although numerous studies have been performed to investigate specific genes, few have looked for evidence of heritability or familial transmission, or for epidemiological patterns that would be consistent with genetically influenced conditions. Future trends, such as genome-wide association studies and epigenetic analysis, should lead to enhanced understanding of the complex interactions within the genome and between the genome and hypoxic environments that contribute to an individual's capacity to acclimatize rapidly and effectively to altitude.
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Affiliation(s)
- Martin J MacInnis
- School of Human Kinetics, University of British Columbia, 6081 University Boulevard, Vancouver, BC, Canada
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Sands M, Howell K, Costello CM, McLoughlin P. Placenta growth factor and vascular endothelial growth factor B expression in the hypoxic lung. Respir Res 2011; 12:17. [PMID: 21266048 PMCID: PMC3040134 DOI: 10.1186/1465-9921-12-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 01/25/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chronic alveolar hypoxia, due to residence at high altitude or chronic obstructive lung diseases, leads to pulmonary hypertension, which may be further complicated by right heart failure, increasing morbidity and mortality. In the non-diseased lung, angiogenesis occurs in chronic hypoxia and may act in a protective, adaptive manner. To date, little is known about the behaviour of individual vascular endothelial growth factor (VEGF) family ligands in hypoxia-induced pulmonary angiogenesis. The aim of this study was to examine the expression of placenta growth factor (PlGF) and VEGFB during the development of hypoxic pulmonary angiogenesis and their functional effects on the pulmonary endothelium. METHODS Male Sprague Dawley rats were exposed to conditions of normoxia (21% O2) or hypoxia (10% O2) for 1-21 days. Stereological analysis of vascular structure, real-time PCR analysis of vascular endothelial growth factor A (VEGFA), VEGFB, placenta growth factor (PlGF), VEGF receptor 1 (VEGFR1) and VEGFR2, immunohistochemistry and western blots were completed. The effects of VEGF ligands on human pulmonary microvascular endothelial cells were determined using a wound-healing assay. RESULTS Typical vascular remodelling and angiogenesis were observed in the hypoxic lung. PlGF and VEGFB mRNA expression were significantly increased in the hypoxic lung. Immunohistochemical analysis showed reduced expression of VEGFB protein in hypoxia although PlGF protein was unchanged. The expression of VEGFA mRNA and protein was unchanged. In vitro PlGF at high concentration mimicked the wound-healing actions of VEGFA on pulmonary microvascular endothelial monolayers. Low concentrations of PlGF potentiated the wound-healing actions of VEGFA while higher concentrations of PlGF were without this effect. VEGFB inhibited the wound-healing actions of VEGFA while VEGFB and PlGF together were mutually antagonistic. CONCLUSIONS VEGFB and PlGF can either inhibit or potentiate the actions of VEGFA, depending on their relative concentrations, which change in the hypoxic lung. Thus their actions in vivo depend on their specific concentrations within the microenvironment of the alveolar wall during the course of adaptation to pulmonary hypoxia.
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Affiliation(s)
- Michelle Sands
- School of Medicine and Medical Science, Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
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23
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Querfurth HW, Lieberman P, Arms S, Mundell S, Bennett M, van Horne C. Ophthalmodynamometry for ICP prediction and pilot test on Mt. Everest. BMC Neurol 2010; 10:106. [PMID: 21040572 PMCID: PMC2987855 DOI: 10.1186/1471-2377-10-106] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 11/01/2010] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND A recent development in non-invasive techniques to predict intracranial pressure (ICP) termed venous ophthalmodynamometry (vODM) has made measurements in absolute units possible. However, there has been little progress to show utility in the clinic or field. One important application would be to predict changes in actual ICP during adaptive responses to physiologic stress such as hypoxia. A causal relationship between raised intracranial pressure and acute mountain sickness (AMS) is suspected. Several MRI studies report that modest physiologic increases in cerebral volume, from swelling, normally accompany subacute ascent to simulated high altitudes. OBJECTIVES 1) Validate and calibrate an advanced, portable vODM instrument on intensive patients with raised intracranial pressure and 2) make pilot, non-invasive ICP estimations of normal subjects at increasing altitudes. METHODS The vODM was calibrated against actual ICP in 12 neurosurgical patients, most affected with acute hydrocephalus and monitored using ventriculostomy/pressure transducers. The operator was blinded to the transducer read-out. A clinical field test was then conducted on a variable data set of 42 volunteer trekkers and climbers scaling Mt. Everest, Nepal. Mean ICPs were estimated at several altitudes on the ascent both across and within subjects. RESULTS Portable vODM measurements increased directly and linearly with ICP resulting in good predictability (r = 0.85). We also found that estimated ICP increases normally with altitude (10 ± 3 mm Hg; sea level to 20 ± 2 mm Hg; 6553 m) and that AMS symptoms did not correlate with raised ICP. CONCLUSION vODM technology has potential to reliably estimate absolute ICP and is portable. Physiologic increases in ICP and mild-mod AMS are separate responses to high altitude, possibly reflecting swelling and vasoactive instability, respectively.
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Affiliation(s)
- Henry W Querfurth
- Dept of Neurology, Rhode Island Hospital, Warren Alpert Medical School, Brown University Providence, RI 02903, USA.
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Patitucci M, Lugrin D, Pagès G. Angiogenic/lymphangiogenic factors and adaptation to extreme altitudes during an expedition to Mount Everest. Acta Physiol (Oxf) 2009; 196:259-65. [PMID: 18983460 DOI: 10.1111/j.1748-1716.2008.01915.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AIM To analyse the correlation between production of angiogenic [vascular endothelial growth factor A (VEGF-A) and interleukin 8 (IL-8)] and lymphangiogenic factors (VEGF-C and D) and adaptation to high altitude (>8000 m). Erythropoietin (EPO) served as a positive control. METHODS We analysed the percentage of oxygen saturation and the plasmatic contents of VEGF-A, C, D, IL-8 and EPO in seven mountaineers and four Sherpas during an expedition to Mount Everest. Acute mountain sickness was also evaluated using the Lake Louise score. RESULTS Whereas VEGF-A, IL-8, VEGF-C and EPO were transiently up-regulated at 5000 m and decreased at the highest altitudes, VEGF-D remained elevated throughout the ascent. Sherpas had increased basal levels of VEGF-A, C, IL-8 and EPO and up-regulation of all the tested factors when they passed the altitude at which they lived. CONCLUSION Our data suggest that expression of angiogenic and lymphangiogenic factors is up-regulated directly or indirectly by altitude-dependent hypoxia. Both factors could be involved in a mechanism of adaptation to high altitudes.
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Affiliation(s)
- M Patitucci
- UMR CNRS 6543, Institute of Signalling, Developmental Biology and Cancer Research, University of Nice Sophia Antipolis, Nice, France
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Hanaoka M, Droma Y, Ota M, Ito M, Katsuyama Y, Kubo K. Polymorphisms of human vascular endothelial growth factor gene in high-altitude pulmonary oedema susceptible subjects. Respirology 2009; 14:46-52. [PMID: 19144048 DOI: 10.1111/j.1440-1843.2008.01420.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Based on the reported biological properties and function of vascular endothelial growth factor (VEGF) in hypoxic conditions, many investigations have studied the hypothesis that VEGF has an important role in the pathogenesis of high altitude sicknesses, including high-altitude pulmonary oedema (HAPE). Unfortunately, the results are inconsistent. Therefore, the association of VEGF gene single nucleotide polymorphisms (SNP) with being susceptible to HAPE was investigated. METHODS The study included 53 HAPE-susceptible subjects (HAPE-s) and 69 HAPE-resistant mountaineer controls (HAPE-r). Subjects were Japanese and the two groups were comparable in terms of age and gender. The SNP of the VEGF gene, namely C-2578A, G-1154A and T-460C in the promoter, G + 405C in the 5'-untranslated region and C936T in the 3'-untranslated region, were examined by allele discrimination experiments. In addition, arterial oxygen tension (PaO(2)) and pulmonary haemodynamic data were available for 21 of the HAPE-s subjects. RESULTS There were no statistically significant differences in the allele frequencies, genotype distributions or haplotype frequencies of VEGF SNP between the HAPE-s and HAPE-r groups. Furthermore, neither PaO(2) nor pulmonary haemodynamic parameters were associated with the VEGF SNP in the 21 HAPE-s subjects. CONCLUSIONS This genetic study did not provide evidence that functional SNP of the VEGF gene are associated with susceptibility to HAPE in a Japanese population.
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Affiliation(s)
- Masayuki Hanaoka
- First Department of Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
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Modulatory effects of seabuckthorn (Hippophae rhamnoides L.) in hypobaric hypoxia induced cerebral vascular injury. Brain Res Bull 2008; 77:246-52. [DOI: 10.1016/j.brainresbull.2008.08.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Revised: 07/18/2008] [Accepted: 08/29/2008] [Indexed: 11/21/2022]
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Kallenberg K, Dehnert C, Dörfler A, Schellinger PD, Bailey DM, Knauth M, Bärtsch PD. Microhemorrhages in nonfatal high-altitude cerebral edema. J Cereb Blood Flow Metab 2008; 28:1635-42. [PMID: 18523438 DOI: 10.1038/jcbfm.2008.55] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Vasogenic edema in the corpus callosum is a characteristic finding in high-altitude cerebral edema (HACE). Furthermore, microhemorrhages have been found at autopsies in brains of HACE victims. The objective of this study was to determine if microhemorrhages also occur in nonlethal HACE. Consequently, magnetic resonance imaging (MRI) was performed in patients who had suffered from HACE and in patients who had suffered from severe acute mountain sickness (AMS) by applying imaging techniques highly susceptible to blood or blood remnants. Two experienced neuroradiologists independently evaluated the exams blinded to clinical data. The MRI was performed 2 to 31 months after the event. The MRI of the HACE patients revealed multiple hemosiderin depositions in the brain--predominantly found in the corpus callosum--indicative of microhemorrhages. These changes were not present in the three AMS patients. In summary, hemosiderin deposits detectable by MRI predominantly in the corpus callosum indicate that microhemorrhages occur in nonlethal HACE, which may serve as a novel diagnostic MRI sign for HACE even many months after the event.
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Affiliation(s)
- Kai Kallenberg
- Department of Neuroradiology, University Medical Center, Georg-August University, Göttingen, Germany
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28
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Abstract
Vascular endothelial growth factor A (VEGF-A) belongs to a family of heparin binding growth factors that include VEGF-B, VEGF-C, VEGF-D, and placental-like growth factor (PLGF). First discovered for its ability to regulate vascular endothelial cell permeability, VEGF is a well-known angiogenic factor that is important for vascular development and maintenance in all mammalian organs. The development of molecular tools and pharmacological agents to selectively inhibit VEGF function and block angiogenesis and/or vascular permeability has led to great promise in the treatment of various cancers, macular degeneration, and wound healing. However, VEGF is also important in animals for the regulation of angiogenesis, stem cell and monocyte/macrophage recruitment, maintenance of kidney and lung barrier functions and neuroprotection. In addition to its role in regulating endothelial cell proliferation, migration, and cell survival, VEGF receptors are also located on many non-endothelial cells and act through autrocrine pathways to regulate cell survival and function. The following review will discuss the role of VEGF in physiological angiogenesis as well as its role in non-angiogenic processes that take place in adult organs.
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Affiliation(s)
- Ellen C Breen
- Department of Medicine, University of California at San Diego, San Diego, La Jolla, California 92093-0623, USA.
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29
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Schlaudraff KU, Pepper MS, Tkatchouk EN, Ehrenburg I, Alizadeh N, Montandon D, Pittet B. Hypoxic Preconditioning Increases Skin Oxygenation and Viability but Does Not Alter VEGF Expression or Vascular Density. High Alt Med Biol 2008; 9:76-88. [DOI: 10.1089/ham.2008.1006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kai U. Schlaudraff
- Plastic & Reconstructive Surgery Unit, University Hospitals of Geneva, Switzerland
| | - Michael S. Pepper
- Netcare Institute of Cellular and Molecular Medicine, Lyttleton, Pretoria, and Department of Immunology, Faculty of Health Sciences, University of Pretoria, South Africa
| | | | - Igor Ehrenburg
- Clinical Research Laboratory of Hypoxia Medical Academy, Moscow, Russia
| | - Navid Alizadeh
- Plastic & Reconstructive Surgery Unit, University Hospitals of Geneva, Switzerland
| | - Denys Montandon
- Plastic & Reconstructive Surgery Unit, University Hospitals of Geneva, Switzerland
| | - Brigitte Pittet
- Plastic & Reconstructive Surgery Unit, University Hospitals of Geneva, Switzerland
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Abstract
Despite declines in prevalence during the past two decades, sudden infant death syndrome (SIDS) continues to be the leading cause of death for infants aged between 1 month and 1 year in developed countries. Behavioural risk factors identified in epidemiological studies include prone and side positions for infant sleep, smoke exposure, soft bedding and sleep surfaces, and overheating. Evidence also suggests that pacifier use at sleep time and room sharing without bed sharing are associated with decreased risk of SIDS. Although the cause of SIDS is unknown, immature cardiorespiratory autonomic control and failure of arousal responsiveness from sleep are important factors. Gene polymorphisms relating to serotonin transport and autonomic nervous system development might make affected infants more vulnerable to SIDS. Campaigns for risk reduction have helped to reduce SIDS incidence by 50-90%. However, to reduce the incidence even further, greater strides must be made in reducing prenatal smoke exposure and implementing other recommended infant care practices. Continued research is needed to identify the pathophysiological basis of SIDS.
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Affiliation(s)
- Rachel Y Moon
- Goldberg Center for Community Pediatric Health, Children's National Medical Center and George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA.
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Brugniaux JV, Hodges ANH, Hanly PJ, Poulin MJ. Cerebrovascular responses to altitude. Respir Physiol Neurobiol 2007; 158:212-23. [PMID: 17544954 DOI: 10.1016/j.resp.2007.04.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 04/17/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
The regulation of cerebral blood flow (CBF) is a complex process that is altered significantly with altitude exposure. Acute exposure produces a marked increase in CBF, in proportion to the severity of the hypoxia and mitigated by hyperventilation-induced hypocapnia when CO(2) is uncontrolled. A number of mediators contribute to the hypoxia-induced cerebral vasodilation, including adenosine, potassium channels, substance P, prostaglandins, and NO. Upon acclimatization to altitude, CBF returns towards normal sea-level values in subsequent days and weeks, mediated by a progressive increase in PO2, first through hyperventilation followed by erythropoiesis. With long-term altitude exposure, a number of mechanisms play a role in regulating CBF, including acid-base balance, hematological modifications, and angiogenesis. Finally, several cerebrovascular disorders are associated with altitude exposure. Existing gaps in our knowledge of CBF and altitude, and areas of future investigation include effects of longer exposures, intermittent hypoxia, and gender differences in the CBF responses to altitude.
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Affiliation(s)
- Julien V Brugniaux
- Department of Physiology & Biophysics, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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32
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Abstract
Hypoxic acclimatization includes increased brain capillary density. Adaptive angiogenesis, which occurs over a 3-week period, is mediated by upregulation of vascular endothelial growth factor induced by hypoxia-inducible factor-1 in concert with the capillary remodeling molecule angiopoietin-2, which is upregulated through cyclooxygenase-2 production of prostaglandin E2. The process is apparently orchestrated by pericytes, which regulate the microvascular milieu and coordinate the interactions within the neurovascular unit. The return to normoxia is accompanied by microvascular regression and decreasing numbers of capillaries to prehypoxic densities. Regression is the result of endothelial cell apoptosis, suggesting the existence of physiologic mechanisms for adjusting capillary density to balance oxygen availability and oxygen consumption. The capacity for adaptation is diminished in older rats because of the attenuation of the hypoxia-inducible factor-1 response.
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Affiliation(s)
- Paula Dore-Duffy
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
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Jafarian S, Gorouhi F, Lotfi J. Reverse association between high-altitude headache and nasal congestion. Cephalalgia 2007; 27:899-903. [PMID: 17593298 DOI: 10.1111/j.1468-2982.2007.01351.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
No evidence is available to show that nasal congestion is a manifestation of exposing an individual to high altitude and hypoxia. Since both nasal congestion and high-altitude headache are vasogenic, we explored whether there is a coincidence between these two symptoms. A prospective observational study was carried out on a cohort of 118 adults (>18 years old) in a mountain clinic at 3450 m. After 24 h of ascent, an interview was held to ask if each individual experienced acute mountain sickness symptoms (headache, etc.) and nasal congestion. Sixty-six (55.9%) individuals mentioned headache within 24 h after ascent and nasal congestion was reported by 34 (28.8%) individuals. There was a reverse association between headache and nasal congestion (P < 0.001). In conclusion, there is a reverse association between altitude headache and nasal congestion, probably as result of contradictory autoregulation effects or exaggerated sympathetic activity.
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Affiliation(s)
- S Jafarian
- Department of Neurology, Tehran University of Medical Sciences (TUMS), Shariati Hospital, Tehran, Iran
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34
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Kowalczyk J, Domal-Kwiatkowska D, Mazurek U, Zembala M, Michalski B, Zembala M. Post-transcriptional modifications of VEGF-A mRNA in non-ischemic dilated cardiomyopathy. Cell Mol Biol Lett 2007; 12:331-47. [PMID: 17297559 PMCID: PMC6275580 DOI: 10.2478/s11658-007-0006-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 11/21/2006] [Indexed: 11/26/2022] Open
Abstract
Vascular endothelial growth factor (VEGF-A) is one of the most important proangiogenic factors. It has many isoforms encoded by one gene. The occurrence of these isoforms is associated with the process of alternative splicing of mRNA. Some of the splice forms are perceived as tissue specific. The aim of this study was to determine the alternative splicing of VEGF-A mRNA in dilated cardiomyopathy, especially at the level of particular myocardial layers. The assessment of post-transcriptional modifications of VEGF-A mRNA was made on specimens taken from the explanted hearts of patients undergoing cardiac transplantation. Molecular and histopathological studies were perfomed on particular layers of the myocardial muscle (endocardium, myocardium, epicardium). A molecular analysis of cardiac samples was performed by quantitative analysis of the mRNA of the studied VEGF-A isoforms (VEGF121, -145, -165, -183, -189, and -206) using QRTPCR with an ABI-PRISM 7700-TaqMan sequence detector. 72 cardiac specimens taken from the explanted hearts were analyzed. Each of the studied VEGF-A splice forms was present in the evaluated hearts, but the types of alternative splicing of mRNA were different in particular layers. Quantitative analysis revealed different amounts of the studied isoforms. Generally, significantly increased expression of the VEGF-A isoforms was observed in samples taken from hearts with post-inflammatory etiology of cardiomyopathy. Our conclusions are: 1. All the studied VEGF-A isoforms were found in the human hearts, including those thusfar considered characteristic for other tissues. 2. Significant differences were observed in the expression of the VEGF-A splice forms with respect to the myocardial layers and the location of the cardiac biopsy. 3. Repetitive and comparable results for samples with post-inflammatory etiology were obtained, and they revealed considerably higher amounts of VEGF-A isoforms compared to specimens with idiopathic etiology.
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Affiliation(s)
- Jacek Kowalczyk
- 1st Department of Cardiology, Silesian Center for Heart Diseases, Zabrze, Medical University of Silesia, Katowice, Poland.
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Zrinzo LU, Crocker M, Zrinzo LV, Thomas DGT, Watkins L. Commercial flight and patients with intracranial mass lesions: a caveat. J Neurosurg 2006; 105:627-30. [PMID: 17044569 DOI: 10.3171/jns.2006.105.4.627] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
✓The authors report two cases of neurological deterioration following long commercial flights. Both individuals harbored intracranial space-occupying lesions. The authors assert that preexisting reduced intracranial compliance diminishes an individual’s reserve to accommodate the physiological changes resulting from a commercial flight. Airline passengers are exposed to a mild degree of hypercapnia as well as conditions that simulate those of high-altitude ascents. High-altitude cerebral edema following an ascent to great heights is one facet of acute mountain sickness and can be life threatening in conditions similar to those present on commercial flights. Comparable reports documenting neurological deterioration at high altitudes in patients with coexisting space-occupying lesions were also reviewed.
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Affiliation(s)
- Ludvic U Zrinzo
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom
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36
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Dorward DA, Thompson AAR, Baillie JK, MacDougall M, Hirani N. Change in plasma vascular endothelial growth factor during onset and recovery from acute mountain sickness. Respir Med 2006; 101:587-94. [PMID: 16890420 DOI: 10.1016/j.rmed.2006.06.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 06/09/2006] [Accepted: 06/14/2006] [Indexed: 11/25/2022]
Abstract
There is an increasing body of evidence suggesting that altered vascular permeability may be an important component of the pathogenesis of acute mountain sickness (AMS). Vascular endothelial growth factor (VEGF) is a potent permeability factor subject to hypoxic regulation but its role in the pathogenesis of AMS is yet to be defined. We examined the relationship between plasma VEGF and AMS on ascent to high altitude and subsequent acclimatisation. Thirty-eight healthy lowlanders (median age 21, range 18-31) flew to La Paz, Bolivia (3650 m) on the Apex 2 research expedition. After 4-5 days acclimatisation, they ascended by vehicle over 90 min to the Chacaltaya laboratory (5200 m). We measured plasma VEGF in venous blood at sea level and at 6 h and 3 and 7 days at 5200 m. AMS was scored using the Lake Louise consensus system. Using serial measurement of plasma VEGF at 5200 m, following partial acclimatisation at 3650 m, we demonstrated a highly significant change in VEGF levels (P<0.0005) with a rise in VEGF in approximately 80% of subjects by day 7 at 5200 m. We found no evidence of an association between AMS and change in VEGF levels on ascent to either 3650 or 5200 m. We provide novel data of change in plasma VEGF levels during acclimatisation to high altitude, but our results do not support the hypothesis that circulating unbound VEGF is an important component of the pathogenesis of AMS.
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Affiliation(s)
- David A Dorward
- APEX (Altitude Physiology Expeditions), College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh EH16 4SB, UK.
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Bailey DM, Roukens R, Knauth M, Kallenberg K, Christ S, Mohr A, Genius J, Storch-Hagenlocher B, Meisel F, McEneny J, Young IS, Steiner T, Hess K, Bärtsch P. Free radical-mediated damage to barrier function is not associated with altered brain morphology in high-altitude headache. J Cereb Blood Flow Metab 2006; 26:99-111. [PMID: 15959459 DOI: 10.1038/sj.jcbfm.9600169] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The present study combined molecular and neuroimaging techniques to examine if free radical-mediated damage to barrier function in hypoxia would result in extracellular edema, raise intracranial pressure (ICP) and account for the neurological symptoms typical of high-altitude headache (HAH) also known as acute mountain sickness (AMS). Twenty-two subjects were randomly exposed for 18 h to 12% (hypoxia) and 21% oxygen (O2 (normoxia)) for collection of venous blood (0 h, 8 h, 15 h, 18 h) and CSF (18 h) after lumbar puncture (LP). Electron paramagnetic resonance (EPR) spectroscopy identified a clear increase in the blood and CSF concentration of O2 and carbon-centered free radicals (P<0.05 versus normoxia) subsequently identified as lipid-derived alkoxyl (LO*) and alkyl (LC*) species. Magnetic resonance imaging (MRI) demonstrated a mild increase in brain volume (7.0+/-4.8 mL or 0.6%+/-0.4%, P<0.05 versus normoxia) that resolved within 6 h of normoxic recovery. However, there was no detectable evidence for gross barrier dysfunction, elevated lumbar pressures, T2 prolongation or associated neuronal and astroglial damage. Clinical AMS was diagnosed in 50% of subjects during the hypoxic trial and corresponding headache scores were markedly elevated (P<0.05 versus non-AMS). A greater increase in brain volume was observed, though this was slight, independent of oxidative stress, barrier dysfunction, raised lumbar pressure, vascular damage and measurable evidence of cerebral edema and only apparent in the most severe of cases. These findings suggest that free-radical-mediated vasogenic edema is not an important pathophysiological event that contributes to the mild brain swelling observed in HAH.
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Affiliation(s)
- Damian M Bailey
- Department of Physiology, University of Glamorgan, Pontypridd, UK.
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38
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Kaur C, Sivakumar V, Zhang Y, Ling EA. Hypoxia-induced astrocytic reaction and increased vascular permeability in the rat cerebellum. Glia 2006; 54:826-39. [PMID: 16977604 DOI: 10.1002/glia.20420] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hypoxia is an important factor linked to induction of vascular leakage and formation of brain edema. In this connection, astrocytes associated closely with the blood vessels are deemed to be involved. This study investigated the response of astrocytes to hypoxia in the adult rat cerebellum, and along with this, the integrity of the blood-brain barrier (BBB) was assessed using fluorescent and electron dense tracers. In rats subjected to hypoxia, mRNA and protein expression of hypoxia inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), glial fibrillary acidic protein (GFAP), and aquaporin-4 (AQ4) was significantly increased. VEGF and AQ4 immunoreactive cells were identified as astrocytes by double immunofluorescence labeling. Increased VEGF tissue concentration and astrocytic swelling as observed in hypoxic rats were reduced after melatonin administration. Following intraperitoneal or intravenous injection of rhodamine isothiocyanate (RhIC) or horseradish peroxidase (HRP), leakage of both tracers was observed in hypoxic rats but not in the controls indicating that functional integrity of BBB is compromised in hypoxia/reoxygenation. Enhanced gene and protein expression of VEGF may contribute to increased permeability of blood vessels. AQ4, a water transporting protein, is upregulated in astrocytes in hypoxia suggesting the cells are involved in edema formation. To this end, melatonin may be beneficial in reducing edema as it reduced VEGF concentration and, hence, vascular permeability.
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MESH Headings
- Animals
- Aquaporin 4/genetics
- Aquaporin 4/metabolism
- Astrocytes/physiology
- Astrocytes/ultrastructure
- Biomarkers/analysis
- Biomarkers/metabolism
- Blood-Brain Barrier/drug effects
- Blood-Brain Barrier/pathology
- Blood-Brain Barrier/physiopathology
- Brain Edema/drug therapy
- Brain Edema/etiology
- Brain Edema/physiopathology
- Capillary Permeability/drug effects
- Capillary Permeability/physiology
- Cell Size
- Cerebral Arteries/physiopathology
- Disease Models, Animal
- Fluorescent Antibody Technique
- Glial Fibrillary Acidic Protein/genetics
- Glial Fibrillary Acidic Protein/metabolism
- Horseradish Peroxidase
- Hypoxia, Brain/complications
- Hypoxia, Brain/physiopathology
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Male
- Melatonin/pharmacology
- Melatonin/therapeutic use
- Microscopy, Electron, Transmission
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Rhodamines
- Up-Regulation/physiology
- Vascular Endothelial Growth Factor A/antagonists & inhibitors
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- C Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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39
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Heine VM, Zareno J, Maslam S, Joëls M, Lucassen PJ. Chronic stress in the adult dentate gyrus reduces cell proliferation near the vasculature and VEGF and Flk-1 protein expression. Eur J Neurosci 2005; 21:1304-14. [PMID: 15813940 DOI: 10.1111/j.1460-9568.2005.03951.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recent evidence has shown that cell proliferation in the adult hippocampal dentate gyrus occurs in tight clusters located near the vasculature. Also, changes in neurogenesis often appear parallel to changes in angiogenesis. Moreover, both these processes share similar modulating factors, like vascular endothelial growth factor (VEGF) and its receptor Flk-1. In an earlier study we found that chronic stress decreased new cell proliferation in the adult dentate gyrus. We here questioned whether these effects of chronic stress are mediated through the vasculature and whether they involve an angiogenic-signaling pathway. We therefore measured the surface area covered by the vasculature, the proportion of vascular-associated newborn cells, and analysed VEGF and Flk-1 protein expression in the hippocampus of a control, chronically stressed and recovery group of rats. Our results show that 32% of the proliferating cells in the rat hippocampus is vascular associated. Chronic stress affected this population of newborn cells to a significantly larger extent than the non-associated cells. Interestingly, after 3 weeks of recovery, the decreased proliferation not associated with the vasculature was more effectively restored than vascular-associated proportion of proliferating cells. VEGF protein was expressed in high densities in GFAP-positive astrocytes located in the hilus, with VEGF-positive end feet extending into and often contacting the granule cells. After chronic stress, both VEGF and Flk-1 protein levels were significantly decreased in the granular cell layer, and again recovered after 3 weeks. This demonstrates that changes in angiogenic factors are implicated in the decreased adult proliferation found after chronic stress.
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Affiliation(s)
- Vivi M Heine
- Institute Neurobiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
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40
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Tissot van Patot MC, Leadbetter G, Keyes LE, Bendrick-Peart J, Beckey VE, Christians U, Hackett P. Greater free plasma VEGF and lower soluble VEGF receptor-1 in acute mountain sickness. J Appl Physiol (1985) 2005; 98:1626-9. [PMID: 15649874 DOI: 10.1152/japplphysiol.00589.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) is a hypoxia-induced protein that produces vascular permeability, and limited evidence suggests a possible role for VEGF in the pathophysiology of acute mountain sickness (AMS) and/or high-altitude cerebral edema (HACE). Previous studies demonstrated that plasma VEGF alone does not correlate with AMS; however, soluble VEGF receptor (sFlt-1), not accounted for in previous studies, can bind VEGF in the circulation, reducing VEGF activity. In the present study, we hypothesized that free VEGF is greater and sFlt-1 less in subjects with AMS compared with well individuals at high altitude. Subjects were exposed to 4,300 m for 19–20 h (baseline 1,600 m). The incidence of AMS was determined by using a modified Lake Louise symptom score and the Environmental Symptoms Questionnaire for cerebral effects. Plasma was collected at low altitude and after 24 h at high altitude, or at time of illness, and then analyzed by ELISA for VEGF and for soluble VEGF receptor, sFlt-1. AMS subjects had lower sFlt-1 at both low and high altitude compared with well subjects and a significant rise in free plasma VEGF on ascent to altitude compared with well subjects. We conclude that increased free plasma VEGF on ascent to altitude is associated with AMS and may play a role in pathophysiology of AMS.
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Affiliation(s)
- Martha C Tissot van Patot
- Department of Anesthesiology, B-113, University of Colorado Health Sciences Center, 4200 E. 9th Ave., Denver, CO 80262, USA.
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41
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Edelman JL, Lutz D, Castro MR. Corticosteroids inhibit VEGF-induced vascular leakage in a rabbit model of blood-retinal and blood-aqueous barrier breakdown. Exp Eye Res 2005; 80:249-58. [PMID: 15670803 DOI: 10.1016/j.exer.2004.09.013] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2004] [Accepted: 09/14/2004] [Indexed: 02/08/2023]
Abstract
PURPOSE Recent clinical studies show that a single intravitreal injection of the corticosteroid triamcinolone acetonide (TAA) may reduce edematous retinal swelling and improve visual acuity in patients with diabetic macular edema (DME). In addition, clinical and experimental studies strongly suggest that blood-retinal barrier breakdown in diabetes is induced by vascular endothelial growth factor (VEGF). These results suggest that corticosteroids may modulate VEGF-mediated responses in vivo. To test this hypothesis directly, the current study evaluated the effects of TAA and dexamethasone (DEX) in a newly developed rabbit model of VEGF-induced blood-retinal barrier and blood-aqueous (iris) barrier breakdown. METHODS VEGF165 or vehicle was injected intravitreally in female Dutch Belt rabbits, and scanning ocular fluorophotometry was used to non-invasively measure fluorescein leakage from retinal and iris vasculature. VEGF-induced retinal vasculopathy was further assessed with fundus imaging, fluorescein angiography, and ocular coherence tomography. For pharmacologic studies, rabbits were treated with either DEX (2 mg kg(-1) daily, s.c.), TAA (2 or 4 mg, intravitreal), indomethacin (20 mg kg(-1) daily, s.c.), or vehicle (s.c. or intravitreal). Human umbilical vein endothelial cells (HUVEC) were loaded with the fluorescent Ca2+ indicator dye fluo-4 and treated with dexamethasone (0.1-10 microM) or vehicle for either 2 or 24 hr prior to stimulation with 10 ng ml(-1) VEGF165. RESULTS VEGF injected intravitreally induced a time and dose-dependent breakdown of the blood-retinal and blood-aqueous barriers. Maximal vascular leakage was measured at 48 hr after intravitreal injection with a dose of 500 ng VEGF. Other effects of VEGF included prominent retinal vasodilation, vessel tortuousity, fluorescein leakage from retinal vessels, and inner retinal edema. These VEGF-mediated responses are transient and approach baseline by 1 week. VEGF-induced blood-retinal and blood-aqueous barrier breakdown was completely blocked by the corticosteroid DEX administered systemically for 3 days. In contrast, the non-steroidal anti-inflammatory drug, indomethacin, had no effect. In a separate study with VEGF injected intravitreally at six different time points over 5 months, a single intravitreal 2 mg dose of TAA completely blocked VEGF-induced retinal and iris leakage for 45 days. VEGF/VEGF receptor-2-mediated Ca2+ mobilization in endothelial cells was not affected by 2 or 24 hr pretreatment with dexamethasone. CONCLUSION These results indicate that one mechanism by which corticosteroids block blood-ocular barrier breakdown and edema is via their modulation of signaling or effector proteins downstream of the VEGF receptor.
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Affiliation(s)
- Jeffrey L Edelman
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA.
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42
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Gupta R, Gray M, Chao T, Bear D, Modafferi E, Mozaffar T. Schwann cells upregulate vascular endothelial growth factor secondary to chronic nerve compression injury. Muscle Nerve 2005; 31:452-60. [PMID: 15685607 DOI: 10.1002/mus.20272] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
To better understand the pathogenesis of chronic nerve compression injuries, we investigated the possibility that Schwann cell production of vascular endothelial growth factor (VEGF) is responsible for the increased vascularity and Schwann cell proliferation associated with chronic nerve injury. In situ hybridization was used to evaluate VEGF mRNA production with immunohistochemistry to further localize the production of VEGF and its receptor proteins in an animal model of chronic nerve compression injury. VEGF mRNA and protein expression increased within Schwann cells as early as 2 weeks after compression and peaked by 1 month with a subsequent marked increase in the number of blood vessels. Thus, chronic nerve compression injury induces Schwann cells to increase VEGF production, which may be responsible for changes in neural vasculature secondary to chronic nerve compression injury. With a better understanding of these nerve injuries, more effective treatments may be developed to help patients with these impairments.
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Affiliation(s)
- Ranjan Gupta
- Peripheral Nerve Research Laboratory, Department of Orthopedic Surgery, Medical Sciences I, Room B120, University of California, Irvine, California 92697, USA.
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43
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Witt KA, Mark KS, Huber J, Davis TP. Hypoxia-inducible factor and nuclear factor kappa-B activation in blood-brain barrier endothelium under hypoxic/reoxygenation stress. J Neurochem 2005; 92:203-14. [PMID: 15606909 DOI: 10.1111/j.1471-4159.2004.02871.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This investigation focuses on transcription factor involvement in blood-brain barrier (BBB) endothelial cell-induced alterations under conditions of hypoxia and post-hypoxia/reoxygenation (H/R), using established in vivo/ex vivo and in vitro BBB models. Protein/DNA array analyses revealed a correlation in key transcription factor activation during hypoxia and H/R, including NFkappaB and hypoxia-inducible factor (HIF)1. Electrophoretic mobility shift assays confirmed NFkappaB and HIF1 binding activity ex vivo and in vitro, under conditions of hypoxia and H/R. Hypoxia- and H/R-treated BBB endothelium showed increased HIF1alpha protein expression in both cytoplasmic and nuclear fractions, in ex vivo and in vitro models. Co-immunoprecipitation of HIF1alpha and HIF1beta was shown in the nuclear fraction under conditions of hypoxia and H/R in both models. Hypoxia- and H/R-treated BBB endothelium showed increased expression of NFkappaB-p65 protein in both cytoplasmic and nuclear fractions. Co-immunoprecipitation of NFkappaB-p65 with NFkappaB-p50 was shown in the nuclear fraction under conditions of hypoxia and H/R in the ex vivo model, and after H/R in the in vitro model. These data offer novel avenues in which to alter and/or investigate BBB activity across model systems and to further our understanding of upstream regulators during hypoxia and H/R.
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Affiliation(s)
- Ken A Witt
- Department of Pharmacology, University of Arizona, College of Medicine, Arizona 85724, USA
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44
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Ratan RR, Siddiq A, Aminova L, Lange PS, Langley B, Ayoub I, Gensert J, Chavez J. Translation of ischemic preconditioning to the patient: prolyl hydroxylase inhibition and hypoxia inducible factor-1 as novel targets for stroke therapy. Stroke 2004; 35:2687-9. [PMID: 15472113 DOI: 10.1161/01.str.0000143216.85349.9e] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Effective therapies for stroke must interdict multiple parallel and sequential pathophysiological events. A paradigm which offers insight into multivalent but thoughtfully coordinated protective programs is ischemic preconditioning. A central hypothesis of our group and others is that pharmacological agents that activate programs of gene expression normally induced by ischemic preconditioning will be effective agents for the prevention and treatment of stroke. Inhibitors of a class of enzymes, the hypoxia inducible factor-1 (HIF-1) prolyl hydroxylases stabilize the transcriptional activator HIF-1 and activate target genes involved in compensation for ischemia, including erythropoeitin (Epo) and vascular endothelial growth factor (VEGF). Here, we review evidence suggesting that the HIF-1 prolyl hyroxylases are inhibited during ischemic preconditioning and that pharmacological inhibitors of these enzymes are viable targets for stroke therapy.
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Affiliation(s)
- Rajiv R Ratan
- Department of Neurology and Neuroscience, Burke/Cornell Medical Research Institute, Weill Medical College of Cornell, White Plains, NY 10605, USA.
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45
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Kalaria RN, Spoors L, Laude EA, Emery CJ, Thwaites-Bee D, Fairlie J, Oakley AE, Barer DH, Barer GR. Hypoxia of sleep apnoea: cardiopulmonary and cerebral changes after intermittent hypoxia in rats. Respir Physiol Neurobiol 2004; 140:53-62. [PMID: 15109928 DOI: 10.1016/j.resp.2004.01.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2004] [Indexed: 11/28/2022]
Abstract
Sleep apnoea (SA) is common, especially in elderly people. In severe cases, arterial P(O2) may be lowered for a third or more in a night of sleep. To simulate the degree and duration of severe SA we exposed rats in a normobaric environmental chamber to 10% O(2) for 4h daily for 56 days (intermittent hypoxia: IH group) and compared them with rats continuously exposed for 8 weeks (continuous hypoxia: CH group) and control rats breathing room air (normoxic: N group). We found significant cardiopulmonary and cerebral changes. Right ventricular hypertrophy developed in IH and to a greater extent in CH. Small peripheral lung vessels developed thicker walls (assessed by a new method), which reduced their lumen, more in CH than IH. Coronal brain sections were immunostained for the glucose-transporter 1 (GLUT1) and the vascular endothelial growth factor (VEGF). The percentages of immunoreactivity in the frontal and temporal cortex, hippocampus, accumbens and putamen were determined by image-capture analysis. We noted GLUT1 immunoreactivity of the capillaries was similarly increased in all regions after CH but less so after IH. However, there was a significant linear trend in GLUT1 reactivity from N to IH to CH (R(2) = 0.73, P = 0.007) that was also confirmed by analysis of variance. The extent of VEGF-stained neurones and glial cells was significantly increased in all regions after IH but not after CH. This suggests that the signals for angiogenesis were complete or arrested after CH. Our findings have implications for the elderly subjected to hypoxic episodes during sleep apnoea.
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Affiliation(s)
- Raj N Kalaria
- Wolfson Centre, Institute for Ageing and Health, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne NE4 6BE, UK
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46
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Yasuhara T, Shingo T, Date I. The Potential Role of Vascular Endothelial Growth Factor in the Central Nervous System. Rev Neurosci 2004; 15:293-307. [PMID: 15526553 DOI: 10.1515/revneuro.2004.15.4.293] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
During the past decade, vascular endothelial growth factor (VEGF) has been widely investigated, and reported to have pleiotropic functions in the central nervous system (CNS) and its supporting physiological environment. VEGF is involved in not only such well-known functions as angiogenesis, accentuation of vessel permeability, and glial proliferation, but also more recently acknowledged functions such as neuroprotection and even neurogenesis itself. Most recently, the neurogenesis function has attracted much attention, and a number of research groups have taken up the challenge of elucidating this activity. In keeping with this trend, our knowledge of VEGF receptors has increased, and certain suggestions concerning the mechanisms of neuroprotection have come to light in the course of the ongoing work, though at times what the researchers had to work with was only a tiny percent of the signal transduction of VEGF. Together with flt-1 (VEGF receptor 1) and flk-1 (VEGF receptor 2), neuropilin (NP) is frequently described as being involved in the neuroprotective effects of VEGF. In this review, both the direct and indirect neuroprotective effects of VEGF, including various signaling pathways as well as the neurogenesis induced by this factor, are discussed in the context of the newly emerging insights into the biological mechanisms of VEGF and closely related, interacting molecules.
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Affiliation(s)
- Takao Yasuhara
- Department of Neurological Surgery, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
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Harrigan MR. Angiogenic factors in the central nervous system. Neurosurgery 2003; 53:639-60; discussion 660-1. [PMID: 12943581 DOI: 10.1227/01.neu.0000079575.09923.59] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2002] [Accepted: 04/24/2003] [Indexed: 01/08/2023] Open
Abstract
The past decade has seen considerable advances in the understanding of angiogenesis. Blood vessel development and growth in the central nervous system are tightly controlled processes that are regulated by angiogenic factors. Angiogenic factors have been implicated in the pathogenesis of a wide variety of disorders, including primary and metastatic brain tumors, aneurysms, arteriovenous malformations, and cavernous malformations. The potential clinical applications of angiogenesis research include inhibition of angiogenesis to control brain tumors and therapeutic angiogenesis to promote collateral blood vessel formation among patients at risk of ischemia. This article summarizes the processes of blood vessel formation in the brain, examines the angiogenic factors that are prominent in the central nervous system, reviews the clinical use of angiogenesis inhibitors, and identifies areas for future investigation.
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Affiliation(s)
- Mark R Harrigan
- Department of Neurosurgery and Toshiba Stroke Research Center, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14209, USA.
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Ray AD, Roberts AJ, Lee SD, Farkas GA, Michlin C, Rifkin DI, Ostrow PT, Krasney JA. Exercise delays the hypoxic thermal response in rats. J Appl Physiol (1985) 2003; 95:272-8. [PMID: 12626482 DOI: 10.1152/japplphysiol.00057.2003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise exacerbates acute mountain sickness. In infants and small mammals, hypoxia elicits a decrease in body temperature (Tb) [hypoxic thermal response (HTR)], which may protect against hypoxic tissue damage. We postulated that exercise would counteract the HTR and promote hypoxic tissue damage. Tb was measured by telemetry in rats (n = 28) exercising or sedentary in either normoxia or hypoxia (10% O2, 24 h) at 25 degrees C ambient temperature (Ta). After 24 h of normoxia, rats walked at 10 m/min on a treadmill (30 min exercise, 30 min rest) for 6 h followed by 18 h of rest in either hypoxia or normoxia. Exercising normoxic rats increased Tb ( degrees C) vs. baseline (39.68 +/- 0.99 vs. 38.90 +/- 0.95, mean +/- SD, P < 0.05) and vs. sedentary normoxic rats (38.0 +/- 0.09, P < 0.05). Sedentary hypoxic rats decreased Tb (36.15 +/- 0.97 vs. 38.0 +/- 0.36, P < 0.05) whereas Tb was maintained in the exercising hypoxic rats during the initial 6 h of exercise (37.61 +/- 0.55 vs. 37.72 +/- 1.25, not significant). After exercise, Tb in hypoxic rats reached a nadir similar to that in sedentary hypoxic rats (35.05 +/- 1.69 vs. 35.03 +/- 1.32, respectively). Tb reached its nadir significantly later in exercising hypoxic vs. sedentary hypoxic rats (10.51 +/- 1.61 vs. 5.36 +/- 1.83 h, respectively; P = 0.002). Significantly greater histopathological damage and water contents were observed in brain and lungs in the exercising hypoxic vs. sedentary hypoxic and normoxic rats. Thus exercise early in hypoxia delays but does not prevent the HTR. Counteracting the HTR early in hypoxia by exercise exacerbates brain and lung damage and edema in the absence of ischemia.
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Affiliation(s)
- A D Ray
- Department of Exercise and Nutrition Science, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
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Abstract
High-altitude illness is the collective term for acute mountain sickness (AMS), high-altitude cerebral oedema (HACE), and high-altitude pulmonary oedema (HAPE). The pathophysiology of these syndromes is not completely understood, although studies have substantially contributed to the current understanding of several areas. These areas include the role and potential mechanisms of brain swelling in AMS and HACE, mechanisms accounting for exaggerated pulmonary hypertension in HAPE, and the role of inflammation and alveolar-fluid clearance in HAPE. Only limited information is available about the genetic basis of high-altitude illness, and no clear associations between gene polymorphisms and susceptibility have been discovered. Gradual ascent will always be the best strategy for preventing high-altitude illness, although chemoprophylaxis may be useful in some situations. Despite investigation of other agents, acetazolamide remains the preferred drug for preventing AMS. The next few years are likely to see many advances in the understanding of the causes and management of high-altitude illness.
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Hanaoka M, Droma Y, Naramoto A, Honda T, Kobayashi T, Kubo K. Vascular endothelial growth factor in patients with high-altitude pulmonary edema. J Appl Physiol (1985) 2003; 94:1836-40. [PMID: 12524373 DOI: 10.1152/japplphysiol.00575.2002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To examine the role of VEGF in the pathogenesis of high-altitude pulmonary edema (HAPE), we measured the concentrations of VEGF in venous serum and bronchoalveolar lavage fluid in patients with HAPE and in healthy volunteers. The VEGF in venous serum of the patients was normal at admission and significantly increased at recovery. Similarly, the VEGF in bronchoalveolar lavage fluid of the patients was increased at recovery compared with admission, but values at both admission and recovery were significantly lower than those of the controls. The present finding suggests that VEGF probably is destroyed in the lung of HAPE, and it appears less likely to have a critical part in the pathogenesis of HAPE but has rather an important role in the repair process for the impaired cell layer.
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Affiliation(s)
- Masayuki Hanaoka
- First Department of Medicine, Shinshu University School of Medicine, Matsumoto 390-8621, Japan.
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