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Haley RW, Kramer G, Xiao J, Dever JA, Teiber JF. Evaluation of a Gene-Environment Interaction of PON1 and Low-Level Nerve Agent Exposure with Gulf War Illness: A Prevalence Case-Control Study Drawn from the U.S. Military Health Survey's National Population Sample. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:57001. [PMID: 35543525 PMCID: PMC9093163 DOI: 10.1289/ehp9009] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND Consensus on the etiology of 1991 Gulf War illness (GWI) has been limited by lack of objective individual-level environmental exposure information and assumed recall bias. OBJECTIVES We investigated a prestated hypothesis of the association of GWI with a gene-environment (GxE) interaction of the paraoxonase-1 (PON1) Q192R polymorphism and low-level nerve agent exposure. METHODS A prevalence sample of 508 GWI cases and 508 nonpaired controls was drawn from the 8,020 participants in the U.S. Military Health Survey, a representative sample survey of military veterans who served during the Gulf War. The PON1 Q192R genotype was measured by real-time polymerase chain reaction (RT-PCR), and the serum Q and R isoenzyme activity levels were measured with PON1-specific substrates. Low-level nerve agent exposure was estimated by survey questions on having heard nerve agent alarms during deployment. RESULTS The GxE interaction of the Q192R genotype and hearing alarms was strongly associated with GWI on both the multiplicative [prevalence odds ratio (POR) of the interaction=3.41; 95% confidence interval (CI): 1.20, 9.72] and additive (synergy index=4.71; 95% CI: 1.82, 12.19) scales, adjusted for measured confounders. The Q192R genotype and the alarms variable were independent (adjusted POR in the controls=1.18; 95% CI: 0.81, 1.73; p=0.35), and the associations of GWI with the number of R alleles and quartiles of Q isoenzyme were monotonic. The adjusted relative excess risk due to interaction (aRERI) was 7.69 (95% CI: 2.71, 19.13). Substituting Q isoenzyme activity for the genotype in the analyses corroborated the findings. Sensitivity analyses suggested that recall bias had forced the estimate of the GxE interaction toward the null and that unmeasured confounding is unlikely to account for the findings. We found a GxE interaction involving the Q-correlated PON1 diazoxonase activity and a weak possible GxE involving the Khamisiyah plume model, but none involving the PON1 R isoenzyme activity, arylesterase activity, paraoxonase activity, butyrylcholinesterase genotypes or enzyme activity, or pyridostigmine. DISCUSSION Given gene-environment independence and monotonicity, the unconfounded aRERI>0 supports a mechanistic interaction. Together with the direct evidence of exposure to fallout from bombing of chemical weapon storage facilities and the extensive toxicologic evidence of biochemical protection from organophosphates by the Q isoenzyme, the findings provide strong evidence for an etiologic role of low-level nerve agent in GWI. https://doi.org/10.1289/EHP9009.
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Affiliation(s)
- Robert W. Haley
- Division of Epidemiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gerald Kramer
- Division of Epidemiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Junhui Xiao
- Division of Epidemiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jill A. Dever
- RTI International, Washington, District of Columbia, USA
| | - John F. Teiber
- Division of Epidemiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Zhang Y, Vakhtin AA, Dietch J, Jennings JS, Yesavage JA, Clark JD, Bayley PJ, Ashford JW, Furst AJ. Brainstem damage is associated with poorer sleep quality and increased pain in gulf war illness veterans. Life Sci 2021; 280:119724. [PMID: 34144059 DOI: 10.1016/j.lfs.2021.119724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/19/2022]
Abstract
AIMS Gulf War Illness (GWI) is manifested as multiple chronic symptoms, including chronic pain, chronic fatigue, sleep problems, neuropsychiatric disorders, respiratory, gastrointestinal, and skin problems. No single target tissue or unifying pathogenic process has been identified that accounts for this variety of symptoms. The brainstem has been suspected to contribute to this multiple symptomatology. The aim of this study was to assess the role of the brainstem in chronic sleep problems and pain in GWI veterans. MATERIALS AND METHODS We enrolled 90 veterans (Age = 50 ± 5, 87% Male) who were deployed to the 1990-91 Gulf War and presented with GWI symptoms. Sleep quality was evaluated using the global Pittsburgh Sleep Quality Index. Pain intensities were obtained with the Brief Pain Inventory sum score. Volumes in cortical, subcortical, brainstem, and brainstem subregions and diffusion tensor metrics in 10 bilateral brainstem tracts were tested for correlations with symptom measures. KEY FINDINGS Poorer sleep quality was significantly correlated with atrophy of the whole brainstem and brainstem subregions (including midbrain, pons, medulla). Poorer sleep quality also significantly correlated with lower fractional anisotropy in the nigrostriatal tract, medial forebrain tract, and the dorsal longitudinal fasciculus. There was a significant correlation between increased pain intensity and decreased fractional anisotropy in the dorsal longitudinal fasciculus. These correlations were not altered after controlling for age, sex, total intracranial volumes, or additional factors, e.g., depression and neurological conditions. SIGNIFICANCE These findings suggest that the brainstem plays an important role in the aberrant neuromodulation of sleep and pain symptoms in GWI.
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Affiliation(s)
- Yu Zhang
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States.
| | | | - Jessica Dietch
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
| | - Jennifer S Jennings
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States
| | - Jerome A Yesavage
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
| | - J David Clark
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
| | - Peter J Bayley
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
| | - J Wesson Ashford
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
| | - Ansgar J Furst
- War Related Illness & Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States; Stanford University, Stanford, CA, United States
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Gean EG, Ayers CK, Winchell KA, Freeman M, Press AM, Paynter R, Kansagara D, Nugent SM. Biological measures and diagnostic tools for Gulf War Illness - A systematic review. Life Sci 2021; 275:119360. [PMID: 33741418 DOI: 10.1016/j.lfs.2021.119360] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/22/2021] [Accepted: 03/07/2021] [Indexed: 10/21/2022]
Abstract
AIMS Gulf War Illness (GWI) is a chronic multisymptom illness with debated etiology and pathophysiology. This systematic review catalogues studies of validated biological tests for diagnosing GWI and of associations between biological measures and GWI for their promise as biomarkers. MAIN METHODS We searched multiple sources through February 2020 for studies of diagnostic tests of GWI and of associations between biological measures and GWI. We abstracted data on study design, demographics, and outcomes. We assessed the risk of bias of included studies. KEY FINDINGS We did not identify any studies validating tests of biomarkers that distinguish cases of GWI from non-cases. We included the best-fitting studies, 32 completed and 24 ongoing or unpublished studies, of associations between GWI and biological measures. The less well-fitting studies (n = 77) were included in a Supplementary Table. Most studies were of the central nervous and immune systems and indicated a significant association of the biological measure with GWI case status. Biological measures were heterogeneous across studies. SIGNIFICANCE Our review indicates that there are no existing validated biological tests to determine GWI case status. Many studies have assessed the potential association between a variety of biological measures and GWI, the majority of which pertain to the immune and central nervous systems. More importantly, while most studies indicated a significant association between biological measures and GWI case status, the biological measures across studies were extremely heterogeneous. Due to the heterogeneity, the focus of the review is to map out what has been examined, rather than synthesize information.
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Affiliation(s)
- Emily G Gean
- Scientific Resource Center for the Agency for Healthcare Research and Quality Evidence-based Practice Center, Portland VA Research Foundation, United States of America.
| | - Chelsea K Ayers
- VA Portland Health Care System Evidence Synthesis Program, United States of America
| | - Kara A Winchell
- VA Portland Health Care System Evidence Synthesis Program, United States of America
| | - Michele Freeman
- VA Portland Health Care System Evidence Synthesis Program, United States of America
| | - Ashlyn M Press
- Cooperative Studies Program Epidemiology Center-Durham, Durham Veterans Affairs Health Care System, Durham, NC, United States of America
| | - Robin Paynter
- VA Portland Health Care System Evidence Synthesis Program, United States of America
| | - Devan Kansagara
- VA Portland Health Care System Evidence Synthesis Program, United States of America
| | - Shannon M Nugent
- VA Portland Health Care System Evidence Synthesis Program, United States of America
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Tillman GD, Spence JS, Briggs RW, Haley RW, Hart J, Kraut MA. Gulf War illness associated with abnormal auditory P1 event-related potential: Evidence of impaired cholinergic processing replicated in a national sample. Psychiatry Res Neuroimaging 2019; 283:7-15. [PMID: 30453127 DOI: 10.1016/j.pscychresns.2018.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/05/2018] [Accepted: 11/09/2018] [Indexed: 10/27/2022]
Abstract
Our team previously reported event-related potential (ERP) and hyperarousal patterns from a study of one construction battalion of the U.S. Naval Reserve who served during the 1991 Persian Gulf War. We sought to replicate these findings in a sample that was more representative of the entire Gulf War-era veteran population, including male and female participants from four branches of the military. We collected ERP data from 40 veterans meeting Haley criteria for Gulf War syndromes 1-3 and from 22 matched Gulf War veteran controls while they performed an auditory oddball task. Reports of hyperarousal from the ill veterans were significantly greater than those from the control veterans, and P1 amplitudes in Syndromes 2 and 3 were significantly higher than P1 amplitudes in Syndrome 1, replicating our previous findings. Many of the contributors to the generation of the P1 potential are also involved in the regulation of arousal and are modulated by cholinergic and dopaminergic systems-two systems whose dysfunction has been implicated in Gulf War illness. These differences among the three syndrome groups where their means were on either side of controls is a replication of our previous ERP study and is consistent with previous imaging studies of this population.
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Affiliation(s)
- Gail D Tillman
- Center for BrainHealth, The University of Texas at Dallas
| | - Jeffrey S Spence
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Richard W Briggs
- Departments of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Robert W Haley
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - John Hart
- Center for BrainHealth, The University of Texas at Dallas; Departments of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Michael A Kraut
- Center for BrainHealth, The University of Texas at Dallas; Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Zukerman G, Fostick L, Ben‐Itzchak E. Early automatic hyperarousal in response to neutral novel auditory stimuli among trauma‐exposed individuals with and without PTSD: An ERP study. Psychophysiology 2018; 55:e13217. [DOI: 10.1111/psyp.13217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 05/21/2018] [Accepted: 05/22/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Gil Zukerman
- Department of Communication Disorders, School of Health SciencesAriel UniversityAriel Israel
| | - Leah Fostick
- Department of Communication Disorders, School of Health SciencesAriel UniversityAriel Israel
| | - Ester Ben‐Itzchak
- Department of Communication Disorders, School of Health SciencesAriel UniversityAriel Israel
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Bloch-Shilderman E, Rabinovitz I, Egoz I, Yacov G, Allon N, Nili U. Determining a threshold sub-acute dose leading to minimal physiological alterations following prolonged exposure to the nerve agent VX in rats. Arch Toxicol 2017; 92:873-892. [DOI: 10.1007/s00204-017-2108-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/26/2017] [Indexed: 10/18/2022]
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Turner MP, Hubbard NA, Himes LM, Faghihahmadabadi S, Hutchison JL, Bennett IJ, Motes MA, Haley RW, Rypma B. Cognitive Slowing in Gulf War Illness Predicts Executive Network Hyperconnectivity: Study in a Population-Representative Sample. Neuroimage Clin 2016; 12:535-541. [PMID: 27672557 PMCID: PMC5030369 DOI: 10.1016/j.nicl.2016.08.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 06/06/2016] [Accepted: 08/24/2016] [Indexed: 12/30/2022]
Abstract
Cognitive slowing is a prevalent symptom observed in Gulf War Illness (GWI). The present study assessed the extent to which functional connectivity between dorsolateral prefrontal cortex (DLPFC) and other task-relevant brain regions was predictive of GWI-related cognitive slowing. GWI patients (n = 54) and healthy veteran controls (n = 29) were assessed on performance of a processing speed task (the Digit Symbol Substitution Task; DSST) while undergoing functional magnetic resonance imaging (fMRI). GWI patients were slower on the DSST relative to controls. Bilateral DLPFC connectivity with task-relevant nodes was altered in GWI patients compared to healthy controls during DSST performance. Moreover, hyperconnectivity in these networks predicted GWI-related increases in reaction time on the DSST, whereas hypoconnectivity did not. These results suggest that GWI-related cognitive slowing reflects reduced efficiency in cortical networks.
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Affiliation(s)
- Monroe P. Turner
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Nicholas A. Hubbard
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Lyndahl M. Himes
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| | | | - Joanna L. Hutchison
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ilana J. Bennett
- Center for the Neurobiology of Learning and Memory, University of California-Irvine, Irvine, CA, USA
| | - Michael A. Motes
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Robert W. Haley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Smith C, Lee R, Moran A, Sipos M. Repeated low-dose exposures to sarin, soman, or VX affect acoustic startle in guinea pigs. Neurotoxicol Teratol 2016; 54:36-45. [DOI: 10.1016/j.ntt.2016.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/21/2015] [Accepted: 01/28/2016] [Indexed: 10/22/2022]
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White RF, Steele L, O'Callaghan JP, Sullivan K, Binns JH, Golomb BA, Bloom FE, Bunker JA, Crawford F, Graves JC, Hardie A, Klimas N, Knox M, Meggs WJ, Melling J, Philbert MA, Grashow R. Recent research on Gulf War illness and other health problems in veterans of the 1991 Gulf War: Effects of toxicant exposures during deployment. Cortex 2015; 74:449-75. [PMID: 26493934 PMCID: PMC4724528 DOI: 10.1016/j.cortex.2015.08.022] [Citation(s) in RCA: 281] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/19/2015] [Accepted: 08/28/2015] [Indexed: 11/01/2022]
Abstract
Veterans of Operation Desert Storm/Desert Shield - the 1991 Gulf War (GW) - are a unique population who returned from theater with multiple health complaints and disorders. Studies in the U.S. and elsewhere have consistently concluded that approximately 25-32% of this population suffers from a disorder characterized by symptoms that vary somewhat among individuals and include fatigue, headaches, cognitive dysfunction, musculoskeletal pain, and respiratory, gastrointestinal and dermatologic complaints. Gulf War illness (GWI) is the term used to describe this disorder. In addition, brain cancer occurs at increased rates in subgroups of GW veterans, as do neuropsychological and brain imaging abnormalities. Chemical exposures have become the focus of etiologic GWI research because nervous system symptoms are prominent and many neurotoxicants were present in theater, including organophosphates (OPs), carbamates, and other pesticides; sarin/cyclosarin nerve agents, and pyridostigmine bromide (PB) medications used as prophylaxis against chemical warfare attacks. Psychiatric etiologies have been ruled out. This paper reviews the recent literature on the health of 1991 GW veterans, focusing particularly on the central nervous system and on effects of toxicant exposures. In addition, it emphasizes research published since 2008, following on an exhaustive review that was published in that year that summarizes the prior literature (RACGWI, 2008). We conclude that exposure to pesticides and/or to PB are causally associated with GWI and the neurological dysfunction in GW veterans. Exposure to sarin and cyclosarin and to oil well fire emissions are also associated with neurologically based health effects, though their contribution to development of the disorder known as GWI is less clear. Gene-environment interactions are likely to have contributed to development of GWI in deployed veterans. The health consequences of chemical exposures in the GW and other conflicts have been called "toxic wounds" by veterans. This type of injury requires further study and concentrated treatment research efforts that may also benefit other occupational groups with similar exposure-related illnesses.
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Affiliation(s)
- Roberta F White
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, United States.
| | - Lea Steele
- Baylor University Institute of Biomedical Studies, Waco, TX, United States.
| | - James P O'Callaghan
- Molecular Neurotoxicology, Toxicology & Molecular Biology Branch (MS-3014), Health Effects Laboratory Division, Centers for Disease Control and Prevention - NIOSH, Morgantown, WV, United States.
| | - Kimberly Sullivan
- Boston University School of Public Health, Department of Environmental Health, Boston, MA, United States.
| | - James H Binns
- Research Advisory Committee on Gulf War Veterans' Illnesses, Phoenix, AZ, United States.
| | | | - Floyd E Bloom
- Molecular & Integrative Neuroscience Department, The Scripps Research Institute, La Jolla, CA, United States.
| | - James A Bunker
- National Gulf War Resource Center, Topeka, KS, United States.
| | - Fiona Crawford
- Director, TBI Research Program, Roskamp Institute, Sarasota, FL, United States.
| | - Joel C Graves
- Captain, U.S. Army, Retired, Crestview, FL, United States.
| | - Anthony Hardie
- Veterans for Common Sense, Bradenton, FL, United States.
| | - Nancy Klimas
- Institute for Neuro-Immune Medicine, Nova Southeastern University, Miami, FL, United States.
| | - Marguerite Knox
- McEntire Joint National Guard Base, Eastover, SC, United States.
| | - William J Meggs
- Department of Emergency Medicine, 3ED311, The Brody School of Medicine, East Carolina University School of Medicine, Greenville, NC, United States.
| | - Jack Melling
- U.S. Government Accountability Office, Salisbury, Wiltshire, UK.
| | | | - Rachel Grashow
- Northeastern University, Department of Civil and Environmental Engineering, Boston, MA, United States.
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Gulf War agent exposure causes impairment of long-term memory formation and neuropathological changes in a mouse model of Gulf War Illness. PLoS One 2015; 10:e0119579. [PMID: 25785457 PMCID: PMC4364893 DOI: 10.1371/journal.pone.0119579] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 01/28/2015] [Indexed: 01/14/2023] Open
Abstract
Gulf War Illness (GWI) is a chronic multisymptom illness with a central nervous system component such as memory deficits, neurological, and musculoskeletal problems. There are ample data that demonstrate that exposure to Gulf War (GW) agents, such as pyridostigmine bromide (PB) and pesticides such as permethrin (PER), were key contributors to the etiology of GWI post deployment to the Persian GW. In the current study, we examined the consequences of acute (10 days) exposure to PB and PER in C57BL6 mice. Learning and memory tests were performed at 18 days and at 5 months post-exposure. We investigated the relationship between the cognitive phenotype and neuropathological changes at short and long-term time points post-exposure. No cognitive deficits were observed at the short-term time point, and only minor neuropathological changes were detected. However, cognitive deficits emerged at the later time point and were associated with increased astrogliosis and reduction of synaptophysin staining in the hippocampi and cerebral cortices of exposed mice, 5 months post exposure. In summary, our findings in this mouse model of GW agent exposure are consistent with some GWI symptom manifestations, including delayed onset of symptoms and CNS disturbances observed in GWI veterans.
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Tobón C, Ibañez A, Velilla L, Duque J, Ochoa J, Trujillo N, Decety J, Pineda D. Emotional processing in Colombian ex-combatants and its relationship with empathy and executive functions. Soc Neurosci 2014; 10:153-65. [DOI: 10.1080/17470919.2014.969406] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Rayhan RU, Stevens BW, Raksit MP, Ripple JA, Timbol CR, Adewuyi O, VanMeter JW, Baraniuk JN. Exercise challenge in Gulf War Illness reveals two subgroups with altered brain structure and function. PLoS One 2013; 8:e63903. [PMID: 23798990 PMCID: PMC3683000 DOI: 10.1371/journal.pone.0063903] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/08/2013] [Indexed: 11/18/2022] Open
Abstract
Nearly 30% of the approximately 700,000 military personnel who served in Operation Desert Storm (1990-1991) have developed Gulf War Illness, a condition that presents with symptoms such as cognitive impairment, autonomic dysfunction, debilitating fatigue and chronic widespread pain that implicate the central nervous system. A hallmark complaint of subjects with Gulf War Illness is post-exertional malaise; defined as an exacerbation of symptoms following physical and/or mental effort. To study the causal relationship between exercise, the brain, and changes in symptoms, 28 Gulf War veterans and 10 controls completed an fMRI scan before and after two exercise stress tests to investigate serial changes in pain, autonomic function, and working memory. Exercise induced two clinical Gulf War Illness subgroups. One subgroup presented with orthostatic tachycardia (n = 10). This phenotype correlated with brainstem atrophy, baseline working memory compensation in the cerebellar vermis, and subsequent loss of compensation after exercise. The other subgroup developed exercise induced hyperalgesia (n = 18) that was associated with cortical atrophy and baseline working memory compensation in the basal ganglia. Alterations in cognition, brain structure, and symptoms were absent in controls. Our novel findings may provide an understanding of the relationship between the brain and post-exertional malaise in Gulf War Illness.
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Affiliation(s)
- Rakib U Rayhan
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Georgetown University Medical Center, Washington, District of Columbia, United States of America.
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Increased brain white matter axial diffusivity associated with fatigue, pain and hyperalgesia in Gulf War illness. PLoS One 2013; 8:e58493. [PMID: 23526988 PMCID: PMC3603990 DOI: 10.1371/journal.pone.0058493] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/07/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Gulf War exposures in 1990 and 1991 have caused 25% to 30% of deployed personnel to develop a syndrome of chronic fatigue, pain, hyperalgesia, cognitive and affective dysfunction. METHODS Gulf War veterans (n = 31) and sedentary veteran and civilian controls (n = 20) completed fMRI scans for diffusion tensor imaging. A combination of dolorimetry, subjective reports of pain and fatigue were correlated to white matter diffusivity properties to identify tracts associated with symptom constructs. RESULTS Gulf War Illness subjects had significantly correlated fatigue, pain, hyperalgesia, and increased axial diffusivity in the right inferior fronto-occipital fasciculus. ROC generated thresholds and subsequent binary regression analysis predicted CMI classification based upon axial diffusivity in the right inferior fronto-occipital fasciculus. These correlates were absent for controls in dichotomous regression analysis. CONCLUSION The right inferior fronto-occipital fasciculus may be a potential biomarker for Gulf War Illness. This tract links cortical regions involved in fatigue, pain, emotional and reward processing, and the right ventral attention network in cognition. The axonal neuropathological mechanism(s) explaining increased axial diffusivity may account for the most prominent symptoms of Gulf War Illness.
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