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Petroff RL, Williams C, Li JL, MacDonald JW, Bammler TK, Richards T, English CN, Baldessari A, Shum S, Jing J, Isoherranen N, Crouthamel B, McKain N, Grant KS, Burbacher TM, Harry GJ. Prolonged, Low-Level Exposure to the Marine Toxin, Domoic Acid, and Measures of Neurotoxicity in Nonhuman Primates. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:97003. [PMID: 36102641 PMCID: PMC9472675 DOI: 10.1289/ehp10923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 07/21/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The excitotoxic molecule, domoic acid (DA), is a marine algal toxin known to induce overt hippocampal neurotoxicity. Recent experimental and epidemiological studies suggest adverse neurological effects at exposure levels near the current regulatory limit (20 ppm, ∼0.075-0.1mg/kg). At these levels, cognitive effects occur in the absence of acute symptoms or evidence of neuronal death. OBJECTIVES This study aimed to identify adverse effects on the nervous system from prolonged, dietary DA exposure in adult, female Macaca fascicularis monkeys. METHODS Monkeys were orally exposed to 0, 0.075, and 0.15mg/kg per day for an average of 14 months. Clinical blood counts, chemistry, and cytokine levels were analyzed in the blood. In-life magnetic resonance (MR) imaging assessed volumetric and tractography differences in and between the hippocampus and thalamus. Histology of neurons and glia in the fornix, fimbria, internal capsule, thalamus, and hippocampus was evaluated. Hippocampal RNA sequencing was used to identify differentially expressed genes. Enrichment of gene networks for neuronal health, excitotoxicity, inflammation/glia, and myelin were assessed with Gene Set Enrichment Analysis. RESULTS Clinical blood counts, chemistry, and cytokine levels were not altered with DA exposure in nonhuman primates. Transcriptome analysis of the hippocampus yielded 748 differentially expressed genes (fold change≥1.5; p≤0.05), reflecting differences in a broad molecular profile of intermediate early genes (e.g., FOS, EGR) and genes related to myelin networks in DA animals. Between exposed and control animals, MR imaging showed comparable connectivity of the hippocampus and thalamus and histology showed no evidence of hypomyelination. Histological examination of the thalamus showed a larger microglia soma size and an extension of cell processes, but suggestions of a GFAP+astrocyte response showed no indication of astrocyte hypertrophy. DISCUSSION In the absence of overt hippocampal excitotoxicity, chronic exposure of Macaca fascicularis monkeys to environmentally relevant levels of DA suggested a subtle shift in the molecular profile of the hippocampus and the microglia phenotype in the thalamus that was possibly reflective of an adaptive response due to prolonged DA exposure. https://doi.org/10.1289/EHP10923.
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Affiliation(s)
- Rebekah L. Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Christopher Williams
- Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
| | - Jian-Liang Li
- Epigenetics & Stem Cell Biology Laboratory, NIEHS, NIH, DHHS, Research Triangle Park, North Carolina, USA
| | - James W. MacDonald
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Theo K. Bammler
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Todd Richards
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | | | - Audrey Baldessari
- Washington National Primate Research Center, Seattle, Washington, USA
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Jing Jing
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
- Center on Human Development and Disability, University of Washington, Seattle, Washington, USA
| | - Brenda Crouthamel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Noelle McKain
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Kimberly S. Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
- Washington National Primate Research Center, Seattle, Washington, USA
| | - Thomas M. Burbacher
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
- Washington National Primate Research Center, Seattle, Washington, USA
- Center on Human Development and Disability, University of Washington, Seattle, Washington, USA
| | - G. Jean Harry
- Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
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Petroff R, Hendrix A, Shum S, Grant KS, Lefebvre KA, Burbacher TM. Public health risks associated with chronic, low-level domoic acid exposure: A review of the evidence. Pharmacol Ther 2021; 227:107865. [PMID: 33930455 DOI: 10.1016/j.pharmthera.2021.107865] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/13/2022]
Abstract
Domoic acid (DA), the causative agent for the human syndrome Amnesic Shellfish Poisoning (ASP), is a potent, naturally occurring neurotoxin produced by common marine algae. DA accumulates in seafood, and humans and wildlife alike can subsequently be exposed when consuming DA-contaminated shellfish or finfish. While strong regulatory limits protect people from the acute effects associated with ASP, DA is an increasingly significant public health concern, particularly for coastal dwelling populations, and there is a growing body of evidence suggesting that there are significant health consequences following repeated exposures to levels of the toxin below current safety guidelines. However, gaps in scientific knowledge make it difficult to precisely determine the risks of contemporary low-level exposure scenarios. The present review characterizes the toxicokinetics and neurotoxicology of DA, discussing results from clinical and preclinical studies after both adult and developmental DA exposure. The review also highlights crucial areas for future DA research and makes the case that DA safety limits need to be reassessed to best protect public health from deleterious effects of this widespread marine toxin.
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Affiliation(s)
- Rebekah Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Alicia Hendrix
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, University of Washington, Seattle, WA, USA
| | - Kathi A Lefebvre
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd. East, Seattle, WA, USA
| | - Thomas M Burbacher
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, University of Washington, Seattle, WA, USA; Infant Primate Research Laboratory, Washington National Primate Research Center, Seattle,WA, USA.
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3
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Gajski G, Gerić M, Domijan AM, Golubović I, Žegura B. Marine toxin domoic acid induces in vitro genomic alterations in human peripheral blood cells. Toxicon 2020; 187:93-100. [PMID: 32891664 DOI: 10.1016/j.toxicon.2020.08.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/29/2020] [Accepted: 08/30/2020] [Indexed: 12/01/2022]
Abstract
Domoic acid (DA) is an excitatory marine neurotoxin produced by diatoms Pseudo-nitzschia spp. as a defence compound that accumulates in the food web and is associated with amnesic shellfish poisoning in humans. Although its toxicity has been well established in marine species, there is limited data on DA cytogenotoxicity in human non-target cells. Therefore, we aimed to investigate the cytogenotoxic potential of DA (0.01-10 μg/mL) in human peripheral blood cells (HPBCs) using a battery of bioassays in vitro. In addition, the influence of DA on oxidative stress parameters as a possible mechanism of action was assessed. Results revealed that DA induced dose- and time-dependent cytotoxic effects. DA significantly affected genomic instability by increasing the frequency of micronuclei and nuclear buds. Furthermore, a slight induction of primary DNA strand breaks was detected after 24 h of exposure accompanied by a significant increase in the number of abnormal size tailed nuclei. No induction of hOGG1 (human 8-oxoguanine DNA glycosylase) sensitive sites was determined upon exposure to DA. Additionally, DA induced oxidative stress by increased production of reactive oxygen species accompanied by changes in glutathione, superoxide dismutase, malondialdehyde and protein carbonyl levels. Overall, the obtained results showed adverse genotoxic effects of DA in non-target HPBCs.
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Affiliation(s)
- Goran Gajski
- Institute for Medical Research and Occupational Health, Mutagenesis Unit, 10000, Zagreb, Croatia.
| | - Marko Gerić
- Institute for Medical Research and Occupational Health, Mutagenesis Unit, 10000, Zagreb, Croatia.
| | - Ana-Marija Domijan
- University of Zagreb, Faculty of Pharmacy and Biochemistry, Department of Pharmaceutical Botany, 10000, Zagreb, Croatia.
| | - Ivana Golubović
- University of Zagreb, Faculty of Pharmacy and Biochemistry, Department of Pharmaceutical Botany, 10000, Zagreb, Croatia
| | - Bojana Žegura
- National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, 1000, Ljubljana, Slovenia.
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4
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Petroff R, Richards T, Crouthamel B, McKain N, Stanley C, Grant KS, Shum S, Jing J, Isoherranen N, Burbacher TM. Chronic, low-level oral exposure to marine toxin, domoic acid, alters whole brain morphometry in nonhuman primates. Neurotoxicology 2019; 72:114-124. [PMID: 30826346 DOI: 10.1016/j.neuro.2019.02.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 01/09/2023]
Abstract
Domoic acid (DA) is an excitatory neurotoxin produced by marine algae and responsible for Amnesiac Shellfish Poisoning in humans. Current regulatory limits (˜0.075-0.1 mg/kg/day) protect against acute toxicity, but recent studies suggest that the chronic consumption of DA below the regulatory limit may produce subtle neurotoxicity in adults, including decrements in memory. As DA-algal blooms are increasing in both severity and frequency, we sought to better understand the effects of chronic DA exposure on reproductive and neurobehavioral endpoints in a preclinical nonhuman primate model. To this end, we initiated a long-term study using adult, female Macaca fascicularis monkeys exposed to daily, oral doses of 0.075 or 0.15 mg/kg of DA for a range of 321-381, and 346-554 days, respectively. This time period included a pre-pregnancy, pregnancy, and postpartum period. Throughout these times, trained data collectors observed intentional tremors in some exposed animals during biweekly clinical examinations. The present study explores the basis of this neurobehavioral finding with in vivo imaging techniques, including diffusion tensor magnetic resonance imaging and spectroscopy. Diffusion tensor analyses revealed that, while DA exposed macaques did not significantly differ from controls, increases in DA-related tremors were negatively correlated with fractional anisotropy, a measure of structural integrity, in the internal capsule, fornix, pons, and corpus callosum. Brain concentrations of lactate, a neurochemical closely linked with astrocytes, were also weakly, but positively associated with tremors. These findings are the first documented results suggesting that chronic oral exposure to DA at concentrations near the current human regulatory limit are related to structural and chemical changes in the adult primate brain.
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Affiliation(s)
- Rebekah Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA.
| | - Todd Richards
- Department of Radiology, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, Seattle, WA, USA
| | - Brenda Crouthamel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Noelle McKain
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Courtney Stanley
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; Center on Human Development and Disability, Seattle, WA, USA
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Jing Jing
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Thomas M Burbacher
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; Center on Human Development and Disability, Seattle, WA, USA; Infant Primate Research Laboratory, Washington National Primate Research Center, Seattle, WA, USA
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5
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Effects of oral domoic acid exposure on maternal reproduction and infant birth characteristics in a preclinical nonhuman primate model. Neurotoxicol Teratol 2019; 72:10-21. [PMID: 30615984 DOI: 10.1016/j.ntt.2019.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/23/2018] [Accepted: 01/03/2019] [Indexed: 11/23/2022]
Abstract
Domoic Acid (DA) is a naturally-occurring excitotoxin, produced by marine algae, which can bioaccumulate in shellfish and finfish. The consumption of seafood contaminated with DA is associated with gastrointestinal illness that, in the case of high DA exposure, can evolve into a spectrum of responses ranging from agitation to hallucinations, memory loss, seizures and coma. Because algal blooms that produce DA are becoming more widespread and very little is known about the dangers of chronic, low-dose exposure, we initiated a preclinical study focused on the reproductive and developmental effects of DA in a nonhuman primate model. To this end, 32 adult female Macaca fascicularis monkeys were orally exposed to 0, 0.075 or 0.15 mg/kg/day DA on a daily basis, prior to and during pregnancy. Females were bred to non-exposed males and infants were evaluated at birth. Results from this study provided no evidence of changes in DA plasma concentrations with chronic exposure. DA exposure was not associated with reproductive toxicity or adverse changes in the physical characteristics of newborns. However, in an unanticipated finding, our clinical observations revealed the presence of subtle neurological effects in the form of intentional tremors in the exposed adult females. While females in both dose groups displayed increased tremoring, the effect was dose-dependent and observed at a higher rate in females exposed to 0.15 mg/kg/day. These results demonstrate that chronic, low-level exposure to DA is associated with injury to the adult CNS and suggest that current regulatory guidelines designed to protect human health may not be adequate for high-frequency shellfish consumers.
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Chen T, Deng Y, Sha L, Shen Y, Xu Q. A cynomolgus monkey model of temporal lobe epilepsy. Brain Res Bull 2018; 144:187-193. [PMID: 30423353 DOI: 10.1016/j.brainresbull.2018.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/01/2018] [Accepted: 11/07/2018] [Indexed: 12/13/2022]
Abstract
Temporal lobe epilepsy (TLE) with hippocampal sclerosis is the most common type of drug-resistant epilepsy. Non-human primates are attractive models for studying the pathogenic mechanisms of TLE, with the goal of developing new drugs and interventions. In this study, we developed and tested a Cynomolgus monkey (Macaca fascicularis) model of TLE. A total of 5 Cynomolgus monkeys received3-4 weekly unilateral hippocampal injections of kainic acid (KA) to induce repetitive acute seizures. Animals were monitored via video and electroencephalography (EEG) to assess KA-induced acute seizures and subsequent spontaneous recurrent epileptiform discharges (SREDs). During acute seizures, EEG recording showed bursts of generalized spike discharges arising from the temporal lobe ipsilateral to the KA injection. Three months later, we detected abundant interictal epileptiform discharges (IEDs) during pentobarbital induced anesthesia. Furthermore, two monkeys exhibited synchronized epileptiform discharges accompanied by symptoms mimicking absence seizures. No obvious convulsive symptoms were observed in any monkeys. Overall, our data indicate successful development of a Cynomolgus monkey model of TLE via unilateral hippocampal injection of KA.
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Affiliation(s)
- Ting Chen
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Yu Deng
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Longze Sha
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100005, China
| | - Yan Shen
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100005, China
| | - Qi Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100005, China.
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Moyer CE, Hiolski EM, Marcinek DJ, Lefebvre KA, Smith DR, Zuo Y. Repeated low level domoic acid exposure increases CA1 VGluT1 levels, but not bouton density, VGluT2 or VGAT levels in the hippocampus of adult mice. HARMFUL ALGAE 2018; 79:74-86. [PMID: 30420019 PMCID: PMC6237202 DOI: 10.1016/j.hal.2018.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Domoic acid (DA) is a neurotoxin produced during harmful algal blooms that accumulates in marine organisms that serve as food resources for humans. While acute DA neurotoxicity can cause seizures and hippocampal lesions, less is known regarding how chronic, subacute DA exposure in adulthood impacts the hippocampus. With more frequent occurrences of harmful algal blooms, it is important to understand the potential impact of repeated, low-level DA exposure on human health. To model repeated, low-dose DA exposure, adult mice received a single low-dose (0.75 ± 0.05 μg/g) of DA or vehicle weekly for 22 consecutive weeks. Quantitative immunohistochemistry was performed to assess the effects of repeated, low-level DA exposure on hippocampal cells and synapses. Vesicular glutamate transporter 1 (VGluT1) immunoreactivity within excitatory boutons in CA1 of DA-exposed mice was increased. Levels of other vesicular transporter proteins (i.e., VGluT2 and the vesicular GABA transporter (VGAT)) within boutons, and corresponding bouton densities, were not significantly altered in CA1, CA3, or dentate gyrus. There were no significant changes in neuron density or glial fibrillary acidic protein (GFAP) immunoreactivity following chronic, low-dose exposure. This suggests that repeated low doses of DA, unlike high doses of DA, do not cause neuronal loss or astrocyte activation in hippocampus in adult mice. Instead, these findings demonstrate that repeated exposure to low levels of DA leads to subtle changes in VGluT1 expression within CA1 excitatory boutons, which may alter glutamatergic transmission in CA1 and disrupt behaviors dependent on spatial memory.
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Affiliation(s)
- Caitlin E Moyer
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, United States
| | - Emma M Hiolski
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, United States
| | - David J Marcinek
- Departments of Radiology, Pathology, and Bioengineering, University of Washington, South Lake Union Campus, 850 Republican St., Brotman 142, Box 358050, Seattle, WA, 98109, United States
| | - Kathi A Lefebvre
- Environmental and Fisheries Science Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. East, Seattle, WA 98112, United States
| | - Donald R Smith
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, United States
| | - Yi Zuo
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, United States.
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Shum S, Kirkwood JS, Jing J, Petroff R, Crouthamel B, Grant KS, Burbacher TM, Nelson WL, Isoherranen N. Validated HPLC-MS/MS Method To Quantify Low Levels of Domoic Acid in Plasma and Urine after Subacute Exposure. ACS OMEGA 2018; 3:12079-12088. [PMID: 30320288 PMCID: PMC6175497 DOI: 10.1021/acsomega.8b02115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
Domoic acid (DA) is a marine neurotoxin produced by several species of Pseudo-nitzschia. DA causes severe neurological toxicity in humans and animals. To address the current analytical need to quantify low levels of DA in human and animal body fluids, a sensitive and selective high performance liquid chromatography-tandem mass spectrometry method was developed to measure DA in plasma and urine. This method was fully validated to accurately and precisely quantify DA between 0.31 and 16 ng/mL in plasma and between 7.8 and 1000 ng/mL in urine. Our group introduced the use of a novel internal standard, tetrahydrodomoic acid to control for matrix effects and other sources of variability. This validated method will be useful to assess DA concentrations in biological samples of human or animal origin after suspected DA exposure from contaminated food. It will also be applicable to sentinel programs and research studies to analyze body fluids with low levels of DA.
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Affiliation(s)
- Sara Shum
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Jay S. Kirkwood
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Jing Jing
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Rebekah Petroff
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Brenda Crouthamel
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Kimberly S. Grant
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Thomas M. Burbacher
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Wendel L. Nelson
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Nina Isoherranen
- Department
of Pharmaceutics, Department of Environmental and Occupational
Health Sciences, Washington National Primate Research Center, Center on Human Development and
Disability, and Department of Medicinal Chemistry, University
of Washington, Health Sciences
Building, 1959 NE Pacific Street, Seattle, Washington 98195, United States
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Ayed Y, Kouidhi B, Kassim S, Bacha H. Proliferative effect of the phycotoxin domoic acid on cancer cell lines: a preliminary evaluation. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2018. [DOI: 10.1080/16583655.2018.1451107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Yosra Ayed
- Department of Oral Basic Science, College of Dentistry, Taibah University, Al-Madinah Al-Munawwarah, KSA
- Laboratory of Research on Biologically Compatible Compounds, Faculty of Dental medicine, Monastir, Tunisia
| | - Bochra Kouidhi
- Faculty of Applied Medical Sciences Yanbu, Department of Medical Laboratory Technologies, Taibah University, Al-Madinah Al-Munawwarah, KSA
| | - Saba Kassim
- Department of Oral Basic Science, College of Dentistry, Taibah University, Al-Madinah Al-Munawwarah, KSA
| | - Hassen Bacha
- Laboratory of Research on Biologically Compatible Compounds, Faculty of Dental medicine, Monastir, Tunisia
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Lefebvre KA, Kendrick PS, Ladiges W, Hiolski EM, Ferriss BE, Smith DR, Marcinek DJ. Chronic low-level exposure to the common seafood toxin domoic acid causes cognitive deficits in mice. HARMFUL ALGAE 2017; 64:20-29. [PMID: 28427569 PMCID: PMC5548283 DOI: 10.1016/j.hal.2017.03.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/15/2017] [Accepted: 03/17/2017] [Indexed: 05/10/2023]
Abstract
The consumption of one meal of seafood containing domoic acid (DA) at levels high enough to induce seizures can cause gross histopathological lesions in hippocampal regions of the brain and permanent memory loss in humans and marine mammals. Seafood regulatory limits have been set at 20mgDA/kg shellfish to protect human consumers from symptomatic acute exposure, but the effects of repetitive low-level asymptomatic exposure remain a critical knowledge gap. Recreational and Tribal-subsistence shellfish harvesters are known to regularly consume low levels of DA. The aim of this study was to determine if chronic low-level DA exposure, at doses below those that cause overt signs of neurotoxicity, has quantifiable impacts on cognitive function. To this end, female C57BL/6NJ mice were exposed to asymptomatic doses of DA (≈0.75mg/kg) or vehicle once a week for several months. Spatial learning and memory were tested in a radial water maze paradigm at one, six and 25 weeks of exposure, after a nine-week recovery period following cessation of exposure, and at three old age time points (18, 24 and 28 months old). Mice from select time points were also tested for activity levels in a novel cage environment using a photobeam activity system. Chronic low-level DA exposure caused significant spatial learning impairment and hyperactivity after 25 weeks of exposure in the absence of visible histopathological lesions in hippocampal regions of the brain. These cognitive effects were reversible after a nine-week recovery period with no toxin exposure and recovery was sustained into old age. These findings identify a new potential health risk of chronic low-level exposure in a mammalian model. Unlike the permanent cognitive impacts of acute exposure, the chronic low-level effects observed in this study were reversible suggesting that these deficits could potentially be managed through cessation of exposure if they also occur in human seafood consumers.
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Affiliation(s)
- Kathi A Lefebvre
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA.
| | - Preston S Kendrick
- Department of Radiology, University of Washington Medical School, Seattle, WA, USA
| | - Warren Ladiges
- Department of Comparative Medicine, University of Washington, Seattle, WA, USA
| | - Emma M Hiolski
- Microbiology and Environmental Toxicology, University of California Santa Cruz, USA
| | - Bridget E Ferriss
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA
| | - Donald R Smith
- Microbiology and Environmental Toxicology, University of California Santa Cruz, USA
| | - David J Marcinek
- Department of Radiology and Department of Bioengineering and Pathology, University of Washington Medical School, Seattle, WA, USA
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Mills BD, Pearce HL, Khan O, Jarrett BR, Fair DA, Lahvis GP. Prenatal domoic acid exposure disrupts mouse pro-social behavior and functional connectivity MRI. Behav Brain Res 2016; 308:14-23. [PMID: 27050322 PMCID: PMC4918767 DOI: 10.1016/j.bbr.2016.03.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 12/29/2022]
Abstract
Domoic acid (DA) is a toxin produced by marine algae and known primarily for its role in isolated outbreaks of Amnestic Shellfish Poisoning and for the damage it inflicts on marine mammals, particularly California sea lions. Lethal effects of DA are often preceded by seizures and coma. Exposure to DA during development can result in subtle and highly persistent effects on brain development and include behavioral changes that resemble diagnostic features of schizophrenia and anomalies in social behavior we believe are relevant to autism spectrum disorder (ASD). To more fully examine this hypothesis, we chose to examine adolescent mice exposed in utero to DA for endpoints relevant to ASD, specifically changes in social behavior and network structure, the latter measured by resting state functional connectivity (rs-fcMRI). We found that male offspring exposed in utero to DA expressed reproducible declines in social interaction and atypical patterns of functional connectivity in the anterior cingulate, a region of the default mode network that is critical for social functioning. We also found disruptions in global topology in regions involved in the processing of reward, social, and sensory experiences. Finally, we found that DA exposed males expressed a pattern of local over-connectivity. These anomalies in brain connectivity bear resemblance to connectivity patterns in ASD and help validate DA-exposed mice as a model of this mental disability.
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Affiliation(s)
- Brian D Mills
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Hadley L Pearce
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Omar Khan
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Ben R Jarrett
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - Damien A Fair
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Department of Psychiatry, Oregon Health & Science University, Portland, OR 97239, United States; Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR 97239, United States
| | - Garet P Lahvis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States.
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Vieira AC, Martínez JMC, Pose RB, Queijo ÁA, Posadas NA, López LMB. Dose-response and histopathological study, with special attention to the hypophysis, of the differential effects of domoic acid on rats and mice. Microsc Res Tech 2015; 78:396-403. [DOI: 10.1002/jemt.22486] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 01/09/2015] [Accepted: 02/14/2015] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Roberto Bermúdez Pose
- Departamento de Anatomía y Producción Animal; Facultad de Veterinaria; Lugo 27002 Spain
| | | | - Nuria Alemañ Posadas
- Departamento de Anatomía y Producción Animal; Facultad de Veterinaria; Lugo 27002 Spain
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13
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Pizzo F, Caloni F, Schreiber NB, Schutz LF, Totty ML, Albonico M, Spicer LJ. Direct effects of the algal toxin, domoic acid, on ovarian function: Bovine granulosa and theca cells as an in vitro model. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 113:314-320. [PMID: 25528487 DOI: 10.1016/j.ecoenv.2014.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/27/2014] [Accepted: 12/02/2014] [Indexed: 06/04/2023]
Abstract
Domoic acid (DA) is a potent neurotoxin produced by alga Pseudo-nitzschia spp. and has been associated with reproductive disorders in mammals. The aim of this study was to investigate if DA can affect the reproductive system via direct action on ovarian function. Bovine granulosa and theca cells were used as in vitro models for evaluating DA effects on ovarian cell proliferation and steroid production. In small-follicle granulosa cells (SMGC), cell proliferation and estradiol (E2) production was not affected (P>0.05) while progesterone (P4) production was inhibited (P<0.05) by DA at all doses tested. In large-follicle granulosa cells (LGGC), DA had no effect (P>0.05) on cell proliferation or P4 production while E2 production was stimulated by 1 and 5 µg/ml DA (P<0.05). DA (1 µg/ml) attenuated (P<0.05) insulin-like growth factor 1 (IGF-1)-induced P4 production by large-follicle theca cells (LGTC), but did not affect androstenedione (A4) production or proliferation of LGTC. In glutamate-free medium, DA inhibited (P<0.05) SMGC E2 production and this inhibition was similar to inhibition of E2 by trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid monohydrate (ACPD; a selective metabotropic glutamate receptor subtype agonist) while kainic acid (KA; an ionotropic glutamate receptor subtype agonist) had no effect (P>0.10) on E2 production. Collectively, these results show for the first time that DA has direct effects on ovarian GC and TC steroidogenesis. Because DA inhibited E2 and P4 production, DA has the potential to be an endocrine disruptor.
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Affiliation(s)
- Fabiola Pizzo
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Francesca Caloni
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Nicole B Schreiber
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Luis F Schutz
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Morgan L Totty
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Marco Albonico
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Leon J Spicer
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
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14
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JANDOVÁ K, KOZLER P, LANGMEIER M, MAREŠOVÁ D, POKORNÝ J, RILJAK V. Influence of Low-Dose Neonatal Domoic Acid on the Spontaneous Behavior of Rats in Early Adulthood. Physiol Res 2014; 63:S521-8. [DOI: 10.33549/physiolres.932936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Consumption of seafood containing toxin domoic acid (DA) causes an alteration of glutamatergic signaling pathways and could lead to various signs of neurotoxicity in animals and humans. Neonatal treatment with domoic acid was suggested as valuable model of schizophrenia and epilepsy. We tested how repeated early postnatal DA administration influences the spontaneous behavior of rats in adulthood. Rats were injected with 30 μg DA/kg from postnatal day (PND) 10 until PND 14. Their behavior was observed in the open field test for one hour (Laboras, Metris) at PND 35, PND 42 and PND 112. We did not find any difference between DA treated rats and animals injected with equivalent volume of saline in both test sessions at PND 35 and PND 42. DA rats at PND 112 exhibited significantly higher vertical and horizontal exploratory activity (tested parameters: locomotion, distance travelled, average speed reached during test, grooming and rearing) between the 30th-40th min of the test session and habituated over 10 min later. We conclude that at least in the given experimental design, neonatal DA treatment results in alteration of the spontaneous behavior of rats in adulthood.
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Affiliation(s)
- K. JANDOVÁ
- Institute of Physiology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
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15
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Perez-Mendes P, Blanco MM, Calcagnotto ME, Cinini SM, Bachiega J, Papoti D, Covolan L, Tannus A, Mello LE. Modeling epileptogenesis and temporal lobe epilepsy in a non-human primate. Epilepsy Res 2011; 96:45-57. [PMID: 21620680 DOI: 10.1016/j.eplepsyres.2011.04.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/29/2011] [Accepted: 04/29/2011] [Indexed: 10/18/2022]
Abstract
Here we describe a new non-human primate model of temporal lobe epilepsy (TLE) to better investigate the cause/effect relationships of human TLE. Status epilepticus (SE) was induced in adult marmosets by pilocarpine injection (250mg/kg; i.p.). The animals were divided in 2 groups: acute (8h post-SE) and chronic (3 and 5 months post-SE). To manage the severity of SE, animals received diazepam 5min after the SE onset (acute group: 2.5 or 1.25mg/kg; i.p.; chronic group/; 1.25mg/kg; i.p). All animals were monitored by video and electrocorticography to assess SE and subsequent spontaneous recurrent seizures (SRS). To evaluate brain injury produced by SE or SRS we used argyrophil III, Nissl and neo-Timm staining techniques. Magnetic resonance image was also performed in the chronic group. We observed that pilocarpine was able to induce SE followed by SRS after a variable period of time. Prolonged SE episodes were associated with brain damage, mostly confined to the hippocampus and limbic structures. Similar to human TLE, anatomical disruption of dentate gyrus was observed after SRS. Our data suggest that pilocarpine marmoset model of epilepsy has great resemblance to human TLE, and could provide new tools to further evaluate the subtle changes associated with human epilepsy.
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Affiliation(s)
- P Perez-Mendes
- Departamento de Fisiologia, Universidade Federal de São Paulo, Brazil
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16
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Sawant PM, Mountfort DO, Kerr DS. Spectral analysis of electrocorticographic activity during pharmacological preconditioning and seizure induction by intrahippocampal domoic acid. Hippocampus 2010; 20:994-1002. [PMID: 19714566 DOI: 10.1002/hipo.20698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previously we have shown that low-dose domoic acid (DA) preconditioning produces tolerance to the behavioral effects of high-dose DA. In this study, we used electrocorticography (ECoG) to monitor subtle CNS changes during and after preconditioning. Young adult male Sprague-Dawley rats were implanted with a left cortical electrode, and acute recordings were obtained during preconditioning by contralateral intrahippocampal administration of either low-dose DA (15 pmoles) or saline, followed by a high-dose DA (100 pmoles) challenge. ECoG data were analyzed by fast Fourier transformation to obtain the percentage of baseline power spectral density (PSD) for delta to gamma frequencies (range: 1.25-100 Hz). Consistent with previous results, behavioral analysis confirmed that low-dose DA preconditioning 60 min before a high-dose DA challenge produced significant reductions in cumulative seizure scores and high level seizure behaviors. ECoG analysis revealed significant reductions in power spectral density across all frequency bands, and high-frequency/high-amplitude spiking in DA preconditioned animals, relative to saline controls. Significant correlations between seizure scores and ECoG power confirmed that behavioral analysis is a reliable marker for seizure analysis. The reduction of power in delta to gamma frequency bands in contralateral cortex does not allow a clear distinction between seizure initiation and seizure propagation, but does provide objective confirmation that pharmacological preconditioning by DA reduces network seizure activity.
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Affiliation(s)
- P M Sawant
- Department of Pharmacology and Toxicology, University of Otago School of Medical Sciences, Dunedin, New Zealand
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17
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Costa LG, Giordano G, Faustman EM. Domoic acid as a developmental neurotoxin. Neurotoxicology 2010; 31:409-23. [PMID: 20471419 PMCID: PMC2934754 DOI: 10.1016/j.neuro.2010.05.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/04/2010] [Accepted: 05/05/2010] [Indexed: 11/21/2022]
Abstract
Domoic acid (DomA) is an excitatory amino acid which can accumulate in shellfish and finfish under certain environmental conditions. DomA is a potent neurotoxin. In humans and in non-human primates, oral exposure to a few mg/kg DomA elicits gastrointestinal effects, while slightly higher doses cause neurological symptoms, seizures, memory impairment, and limbic system degeneration. In rodents, which appear to be less sensitive than humans or non-human primates, oral doses cause behavioral abnormalities (e.g. hindlimb scratching), followed by seizures and hippocampal degeneration. Similar effects are also seen in other species (from sea lions to zebrafish), indicating that DomA exerts similar neurotoxic effects across species. The neurotoxicity of DomA is ascribed to its ability to interact and activate the AMPA/KA receptors, a subfamily of receptors for the neuroexcitatory neurotransmitter glutamate. Studies exploring the neurotoxic effects of DomA on the developing nervous system indicate that DomA elicits similar behavioral, biochemical and morphological effects as in adult animals. However, most importantly, developmental neurotoxicity is seen at doses of DomA that are one to two orders of magnitude lower than those exerting neurotoxicity in adults. This difference may be due to toxicokinetic and/or toxicodynamic differences. Estimated safe doses may be exceeded in adults by high consumption of shellfish contaminated with DomA at the current limit of 20 microg/g. Given the potential higher susceptibility of the young to DomA neurotoxicity, additional studies investigating exposure to, and effects of this neurotoxin during brain development are warranted.
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Affiliation(s)
- Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
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18
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Lefebvre KA, Robertson A. Domoic acid and human exposure risks: A review. Toxicon 2010; 56:218-30. [DOI: 10.1016/j.toxicon.2009.05.034] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 05/06/2009] [Accepted: 05/13/2009] [Indexed: 01/20/2023]
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Bakke MJ, Hustoft HK, Horsberg TE. Subclinical effects of saxitoxin and domoic acid on aggressive behaviour and monoaminergic turnover in rainbow trout (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:1-9. [PMID: 20409597 DOI: 10.1016/j.aquatox.2010.03.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 03/03/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
The algal produced neurotoxins saxitoxin and domoic acid may have serious effects on marine life and can be responsible for the intoxication of for instance sea mammals, sea birds and fish. Given that farmed fish cannot escape algal blooms, they may be more susceptible to intoxication than wild stocks. In the present study, subclinical effects of saxitoxin and domoic on aggressive behaviour and monoaminergic systems in the brain of the rainbow trout (Oncorhynchus mykiss) were investigated. The resident-intruder test was used to measure aggression where only the resident fish were subjected to the toxins and analysed for monoamines and their metabolites. The resident-intruder test was carried out on two consecutive days. On day one basal aggression was measured in the four groups. On day two three of the groups were injected with subclinical doses of one of the following: saxitoxin (1.752 microg/kg bw), domoic (0.75 mg/kg bw) or 0.9% saline solution. This was performed 30 min prior to the aggression test. Handling stress and injection affected aggressive behaviour, cortisol and the serotonergic system in telencephalic brain regions. Cortisol levels were elevated in all of the injected groups when compared to the control group. An increase in serotonergic turnover was evident when all injected groups were pooled and compared to the control group. All together this suggests that the handling stress in connection with the injection was similar in all of the three injected groups. In contrast to both the undisturbed control group and the toxin-injected groups, the saline-injected group displayed a reduction in aggressive behaviour which was evident in increased attack latency. Furthermore the domoic injected group displayed more aggressive attacks towards their conspecifics than the saline-injected group. Consequently the two toxins appear to mask the stress induced alteration in aggressive behaviour. Monoamine levels and monoaminergic turnover could not be demonstrated to be directly affected by the two toxins at the given doses in the investigated brain regions (dorsal and ventral parts of telencephalon, optic tectum, locus coeruleus, raphe nucleus, molecular and granular layer of cerebellum). This could indicate that the toxins mediate aggressive behaviour either through other systems than the monoaminergic systems, such as neuroactive amino acids, or that the mediation occurs in other brain regions.
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Affiliation(s)
- Marit Jørgensen Bakke
- Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, N-0033 Oslo, Norway.
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20
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Stewart I. Environmental risk factors for temporal lobe epilepsy – Is prenatal exposure to the marine algal neurotoxin domoic acid a potentially preventable cause? Med Hypotheses 2010; 74:466-81. [DOI: 10.1016/j.mehy.2009.10.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 10/04/2009] [Indexed: 01/29/2023]
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Grant KS, Burbacher TM, Faustman EM, Gratttan L. Domoic acid: neurobehavioral consequences of exposure to a prevalent marine biotoxin. Neurotoxicol Teratol 2009; 32:132-41. [PMID: 19799996 DOI: 10.1016/j.ntt.2009.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 09/22/2009] [Accepted: 09/22/2009] [Indexed: 11/17/2022]
Abstract
Domoic acid (DA), the cause of Amnesic Shellfish Poisoning, is a naturally occurring marine biotoxin that is usually produced by the microscopic algae Pseudo-nitzschia. As is the case for other types of toxic algae, Pseudo-nitzschia outbreaks are becoming more frequent. Acute high-dose symptomology in humans includes vomiting, cramping, coma and death as well as neurological effects such as hallucinations, confusion and memory loss. Experimental studies and medical reports have collectively shown that DA exposure primarily affects the hippocampal regions of the brain and is associated with seizures and the disruption of cognitive processes. The neurobehavioral signature of DA is unique in that it includes transient and permanent changes in memory function that resemble human antegrade amnesia. Experimental studies with adult nonhuman primates have established that DA is a dose-dependent emetic that produces clinical and neuropathological changes consistent with excitotoxicity. Behavioral evaluations of treated rodents have shown that hyperactivity and stereotypical scratching are the first functional markers of toxicity. Mid-dose treatment is associated with memory impairment and behavioral hyperreactivity, suggesting changes in arousal and/or emotionality. At higher doses, DA treatment results in frank neurotoxicity that is characterized by seizures, status epilepticus and death in treated animals. The route of DA exposure is important and influences the severity of effects; intraperitoneal and intravenous treatments produce classic signs of poisoning at significantly lower doses than oral exposure. While developmental studies are few, DA readily crosses the placenta and enters the fetal brain. Domoic acid is not associated with congenital dysmorphia but is linked to persistent changes in motor behavior and cognition in exposed offspring. Comparative research suggests that functional losses associated with DA can be persistent and injuries to the CNS can be progressive. Long-term studies will be necessary to accurately track the expression of DA-related injury, in health and behavior, over the lifespan.
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Affiliation(s)
- Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA 98195, USA.
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22
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23
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Sawant P, Holland P, Mountfort D, Kerr D. In vivo seizure induction and pharmacological preconditioning by domoic acid and isodomoic acids A, B and C. Neuropharmacology 2008; 55:1412-8. [DOI: 10.1016/j.neuropharm.2008.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 07/30/2008] [Accepted: 09/01/2008] [Indexed: 10/21/2022]
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Goldstein T, Mazet JAK, Zabka TS, Langlois G, Colegrove KM, Silver M, Bargu S, Van Dolah F, Leighfield T, Conrad PA, Barakos J, Williams DC, Dennison S, Haulena M, Gulland FMD. Novel symptomatology and changing epidemiology of domoic acid toxicosis in California sea lions (Zalophus californianus): an increasing risk to marine mammal health. Proc Biol Sci 2008; 275:267-76. [PMID: 18006409 DOI: 10.1098/rspb.2007.1221] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Harmful algal blooms are increasing worldwide, including those of Pseudo-nitzschia spp. producing domoic acid off the California coast. This neurotoxin was first shown to cause mortality of marine mammals in 1998. A decade of monitoring California sea lion (Zalophus californianus) health since then has indicated that changes in the symptomatology and epidemiology of domoic acid toxicosis in this species are associated with the increase in toxigenic blooms. Two separate clinical syndromes now exist: acute domoic acid toxicosis as has been previously documented, and a second novel neurological syndrome characterized by epilepsy described here associated with chronic consequences of previous sub-lethal exposure to the toxin. This study indicates that domoic acid causes chronic damage to California sea lions and that these health effects are increasing.
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Affiliation(s)
- T Goldstein
- The Marine Mammal Center, 1065 Fort Cronkhite, Sausalito, CA 94965, USA.
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26
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Domoic acid toxicologic pathology: a review. Mar Drugs 2008; 6:180-219. [PMID: 18728725 PMCID: PMC2525487 DOI: 10.3390/md20080010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 05/16/2008] [Accepted: 05/16/2008] [Indexed: 12/29/2022] Open
Abstract
Domoic acid was identified as the toxin responsible for an outbreak of human poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels [Mytilus edulis]. The poisoning was characterized by a constellation of clinical symptoms and signs. Among the most prominent features described was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Domoic acid is produced by certain marine organisms, such as the red alga Chondria armata and planktonic diatom of the genus Pseudo-nitzschia. Since 1987, monitoring programs have been successful in preventing other human incidents of ASP. However, there are documented cases of domoic acid intoxication in wild animals and outbreaks of coastal water contamination in many regions world-wide. Hence domoic acid continues to pose a global risk to the health and safety of humans and wildlife. Several mechanisms have been implicated as mediators for the effects of domoic acid. Of particular importance is the role played by glutamate receptors as mediators of excitatory neurotransmission and the demonstration of a wide distribution of these receptors outside the central nervous system, prompting the attention to other tissues as potential target sites. The aim of this document is to provide a comprehensive review of ASP, DOM induced pathology including ultrastructural changes associated to subchronic oral exposure, and discussion of key proposed mechanisms of cell/tissue injury involved in DOM induced brain pathology and considerations relevant to food safety and human health.
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Giordano G, Klintworth HM, Kavanagh TJ, Costa LG. Apoptosis induced by domoic acid in mouse cerebellar granule neurons involves activation of p38 and JNK MAP kinases. Neurochem Int 2007; 52:1100-5. [PMID: 18164102 DOI: 10.1016/j.neuint.2007.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 11/01/2007] [Accepted: 11/19/2007] [Indexed: 10/22/2022]
Abstract
In mouse cerebellar granule neurons (CGNs) the marine neurotoxin domoic acid (DomA) induces neuronal cell death, either by apoptosis or by necrosis, depending on its concentration, with apoptotic damage predominating in response to low concentrations (100 nM). DomA-induced apoptosis is due to selective activation of AMPA/kainate receptors, and is mediated by DomA-induced oxidative stress, leading to mitochondrial dysfunction and activation of caspase-3. The p38 MAP kinase and the c-Jun NH2-terminal protein kinase (JNK) have been shown to be preferentially activated by oxidative stress. Here we report that DomA increases p38 MAP kinase and JNK phosphorylation, and that this effect is more pronounced in CGNs from Gclm (-/-) mice, which lack the modifier subunit of glutamate-cysteine ligase, have very low glutathione (GSH) levels, and are more sensitive to DomA-induced apoptosis than CGNs from wild-type mice. The increased phosphorylation of JNK and p38 kinase was paralleled by a decreased phosphorylation of Erk 1/2. The AMPA/kainate receptor antagonist NBQX, but not the NMDA receptor antagonist MK-801, prevents DomA-induced activation of p38 and JNK kinases. Several antioxidants (GSH ethyl ester, catalase and phenylbutylnitrone) also prevent DomA-induced phosphorylation of JNK and p38 MAP kinases. Inhibitors of p38 (SB203580) and of JNK (SP600125) antagonize DomA-induced apoptosis. These results indicate the importance of oxidative stress-activated JNK and p38 MAP kinase pathways in DomA-induced apoptosis in CGNs.
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Affiliation(s)
- G Giordano
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA
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28
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Hesp BR, Clarkson AN, Sawant PM, Kerr DS. Domoic acid preconditioning and seizure induction in young and aged rats. Epilepsy Res 2007; 76:103-12. [PMID: 17716870 DOI: 10.1016/j.eplepsyres.2007.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 05/21/2007] [Accepted: 07/10/2007] [Indexed: 11/28/2022]
Abstract
Clinical reports suggest that the elderly are hypersensitive to the neurological effects of domoic acid (DOM). In the present study we assessed DOM-induced seizures in young and aged rats, and seizure attenuation following low-dose DOM pretreatment (i.e. preconditioning). Seizure behaviours following saline or DOM administration (0.5-2mg/kg i.p.) were continuously monitored for 2.5h in naïve and DOM preconditioned rats. Competitive ELISA was used to determine serum and brain DOM concentrations. Dose- and age-dependent increases in seizure activity were evident in response to DOM. Lower doses of DOM in young and aged rats promoted low level seizure behaviours. Animals administered high doses (2mg/kg in young; 1mg/kg in aged) progressed through various stages of stereotypical behaviour (e.g., head tics, scratching, wet dog shakes) before ultimately exhibiting tonic-clonic convulsions. Serum and brain DOM analysis indicated impaired renal clearance as contributory to increased DOM sensitivity in aged animals, and this was supported by seizure analysis following direct intrahippocampal administration of DOM. Preconditioning young and aged animals with low-dose DOM 45-90 min before high-dose DOM significantly reduced seizure intensity. We conclude that age-related supersensitivity to DOM is related to reduced clearance rather than increased neuronal sensitivity, and that preconditioning mechanisms underlying an inducible tolerance to excitotoxins are robustly expressed in both young and aged CNS.
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Affiliation(s)
- Blair R Hesp
- Department of Pharmacology & Toxicology, University of Otago School of Medical Sciences, Dunedin, New Zealand
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29
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Giordano G, White CC, McConnachie LA, Fernandez C, Kavanagh TJ, Costa LG. Neurotoxicity of domoic Acid in cerebellar granule neurons in a genetic model of glutathione deficiency. Mol Pharmacol 2006; 70:2116-26. [PMID: 17000861 DOI: 10.1124/mol.106.027748] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This study investigated the role of cellular antioxidant defense mechanisms in modulating the neurotoxicity of domoic acid (DomA), by using cerebellar granule neurons (CGNs) from mice lacking the modifier subunit of glutamate-cysteine ligase (Gclm). Glutamate-cysteine ligase (Glc) catalyzes the first and rate-limiting step in glutathione (GSH) biosynthesis. CGNs from Gclm (-/-) mice have very low levels of GSH and are 10-fold more sensitive to DomA-induced toxicity than CGNs from Gclm (+/+) mice. GSH ethyl ester decreased, whereas the Gcl inhibitor buthionine sulfoximine increased DomA toxicity. Antagonists of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptors and of N-methyl-D-aspartate (NMDA) receptors blocked DomA toxicity, and NMDA receptors were activated by DomA-induced l-glutamate release. The differential susceptibility of CGNs to DomA toxicity was not due to a differential expression of ionotropic glutamate receptors, as evidenced by similar calcium responses and L-glutamate release in the two genotypes. A calcium chelator and several antioxidants antagonized DomA-induced toxicity. DomA caused a rapid decrease in cellular GSH, which preceded toxicity, and the decrease was primarily due to DomA-induced GSH efflux. DomA also caused an increase in oxidative stress as indicated by increases in reactive oxygen species and lipid peroxidation, which was subsequent to GSH efflux. Astrocytes from both genotypes were resistant to DomA toxicity and presented a diminished calcium response to DomA and a lack of DomA-induced L-glutamate release. Because polymorphisms in the GCLM gene in humans are associated with low GSH levels, such individuals, as well as others with genetic conditions or environmental exposures that lead to GSH deficiency, may be more susceptible to DomA-induced neurotoxicity.
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Affiliation(s)
- G Giordano
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Suite 100, Seattle, WA 98105, USA
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Scallet AC, Schmued LC, Johannessen JN. Neurohistochemical biomarkers of the marine neurotoxicant, domoic acid. Neurotoxicol Teratol 2005; 27:745-52. [PMID: 16203121 DOI: 10.1016/j.ntt.2005.06.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 02/01/2005] [Indexed: 11/25/2022]
Abstract
Domoic acid and its potent excitotoxic analogues glutamic acid and kainic acid, are synthesized by marine algae such as seaweed and phytoplankton. During an algal bloom, domoic acid may enter the food web through its consumption by a variety of marine organisms held in high regard as seafoods by both animals and humans. These seafoods include clams, mussels, oysters, anchovies, sardines, crabs, and scallops, among others. Animals, such as pelicans, cormorants, loons, grebes, sea otters, dolphins, and sea lions, which consume seafood contaminated with domoic acid, suffer disorientation and often death. Humans consuming contaminated seafood may suffer seizures, amnesia and also sometimes death. In addition to analytical measurement of domoic acid exposure levels in algae and/or seafood, it is useful to be able to identify the mode of toxicity through post-mortem evaluation of the intoxicated animal. In the present study, using the rat as an animal model of domoic acid intoxication, we compared histochemical staining of the limbic system and especially the hippocampus with degeneration-selective techniques (Fluoro-Jade and silver), a conventional Nissl stain for cytoplasm (Cresyl violet), a myelin-selective stain (Black-Gold), an astrocyte-specific stain (glial fibrillary acidic protein), early/immediate gene responses (c-Fos and c-Jun), as well as for heat shock protein (HSP-72) and blood-brain barrier integrity (rat IgG). The results demonstrate that the degeneration-selective stains are the biomarkers of domoic acid neurotoxicity that are the most useful and easy to discern when screening brain sections at low magnification. We also observed that an impairment of blood-brain barrier integrity within the piriform cortex accompanied the onset of domoic acid neurotoxicity.
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Affiliation(s)
- Andrew C Scallet
- Division of Neurotoxicology, National Center for Toxicological Research/FDA 3900 NCTR Drive, Jefferson, Arkansas 72079, USA.
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31
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Jeffery B, Barlow T, Moizer K, Paul S, Boyle C. Amnesic shellfish poison. Food Chem Toxicol 2004; 42:545-57. [PMID: 15019178 DOI: 10.1016/j.fct.2003.11.010] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2002] [Accepted: 11/07/2003] [Indexed: 11/22/2022]
Abstract
Amnesic shellfish poisoning (ASP) is caused by consumption of shellfish that have accumulated domoic acid, a neurotoxin produced by some strains of phytoplankton. The neurotoxic properties of domoic acid result in neuronal degeneration and necrosis in specific regions of the hippocampus. A serious outbreak of ASP occurred in Canada in 1987 and involved 150 reported cases, 19 hospitalisations and 4 deaths after consumption of contaminated mussels. Symptoms ranged from gastrointestinal disturbances, to neurotoxic effects such as hallucinations, memory loss and coma. Monitoring programmes are in place in numerous countries worldwide and closures of shellfish harvesting areas occur when domoic acid concentrations exceed regulatory limits. This paper reviews the chemistry, sources, metabolism and toxicology of domoic acid as well as human case reports of ASP and discusses a possible mechanism of toxicity.
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Affiliation(s)
- B Jeffery
- Food Standards Agency, Aviation House, 125 Kingsway, London WC2B 6NH, UK.
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32
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Abstract
Environmental chemicals involved in the etiology of human neurodegenerative disorders are challenging to identify. Described here is research designed to determine the etiology and molecular pathogenesis of nerve cell degeneration in two little known corticomotoneuronal diseases with established environmental triggers. Both conditions are toxic-nutritional disorders dominated by persistent spastic weakness of the legs and degeneration of corresponding corticospinal pathways. Lathyrism, a disease caused by dietary dependence on grass pea (Lathyrus sativus), is mediated by a stereospecific plant amino acid (beta-N-oxalylamino-L-alanine) that serves as a potent agonist at the (RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) subclass of neuronal glutamate receptors. A neurologically similar disorder, konzo ("tied legs"), is found among protein-poor African communities that rely for food on cyanogen-containing cassava roots. Thiocyanate, the principal metabolite of cyanide, is an attractive etiologic candidate for konzo because it selectively promotes the action of glutamate at AMPA receptors. Studies are urgently needed to assess the health effects of cassava and other cyanogenic plants, components of which are widely used as food.
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Affiliation(s)
- P S Spencer
- Department of Neurology, School of Medicine, Oregon Health Sciences University, Portland 97201, USA
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Slikker W, Scallet AC, Gaylor DW. Biologically-based dose-response model for neurotoxicity risk assessment. Toxicol Lett 1998; 102-103:429-33. [PMID: 10022291 DOI: 10.1016/s0378-4274(98)00335-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Domoic acid is a tricarboxylic amino acid that is structurally-related to kainic acid and glutamic acid. It is produced by phytoplankton that may contaminate seafood. To determine domoate's toxicological effects and their pathogenesis, cynomolgus monkeys were dosed intravenously at one of a range of bolus doses from 0.25 to 4.0 mg/kg. Histochemical staining, using silver methods, revealed degenerating axons and cell bodies. Doses in the range of 0.5-1.0 mg/kg produced a small area of silver grains restricted to axons of the hippocampal CA2 stratum lucidum, the most sensitive brain area identified. Quantitation of the abundance of these silver grains yielded continuous dose-response data. A four step quantitative risk estimation approach was used: (1) determination of a dose-response model; (2) determination of the distribution of measurements (variability) about the model; (3) determination of an adverse or abnormal level with the use of the control data; and (4) estimation of the probability that a measure is beyond the abnormal level as a function of dose. The currently used safety-factor (S-F) approach, the benchmark (BM) approach and this quantitative (Q) approach was used to assess the same data set. Assuming a 5% oral absorption of domoic acid, acceptable doses would be achieved if subjects ate 200 g of seafood containing 12, 6 and 10 ppm domoic acid for the S-F, BM and Q approaches, respectively. This quantitative approach uses all the available data, takes into account the variability of the data and provides an actual risk at a given dose of domoic acid.
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Affiliation(s)
- W Slikker
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, Jefferson, AR 72079-9502, USA.
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Scallet AC, Ye X. Excitotoxic mechanisms of neurodegeneration in transmissible spongiform encephalopathies. Ann N Y Acad Sci 1997; 825:194-205. [PMID: 9369987 DOI: 10.1111/j.1749-6632.1997.tb48429.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Endogenous excitatory amino acids (EAAs) such as glutamic or aspartic acids have been proposed to mediate the brain damage to EAA receptor-rich brain sites that is caused by a variety of external toxic agents (glutamic acid, domoic acid, kainic acid, ibogaine, trimethyltin (TMT), 3-nitropropionic acid (3-NPA)), as well as from such naturally-occurring age-related neurodegenerative diseases as Alzheimer's disease, Huntington's chorea, and Parkinson's disease. Sites often damaged include the hypothalamus (glutamate), the hippocampal and neocortical pyramidal neurons (domoic acid), the cerebellar Purkinje neurons (ibogaine) and the corpus striatum (3-NPA, amphetamine). The excitotoxic damage occurs to neuronal cell bodies and their dendrites, resulting in a characteristics appearance of pyknotic neurons surrounded by their vacuolated, swollen dendrites. Axons passing through the region that lack EAA receptors are completely spared. However, astrocytes with swollen perikarya and nuclei (Alzheimer's type II "reactive" astrocytes) are often observed in the vicinity of the lesions. Animal and human "Prion Diseases" or "Transmissible Spongiform Encephalopathies" (TSEs) result (after a period of months to years) in a neurodegenerative picture characterized by pyknotic neurons surrounded by vacuoles with numerous reactive astrocytes in the vicinity of the damage. In addition, amyloid deposits composed of a protease-resistant protein (PrPSc) characteristic of the particular host species with the disease are found near the degenerating neurons. By using different strains of the scrapies TSE agent to inoculate hamsters and mice, reproducible models of hypothalamic, hippocampal, or cerebellar damage resulting in the appropriate functional deficits may be obtained. Because of the close similarity in the appearance, localization, and functional consequences from TSE neuropathology compared to some of the well-known EAA syndromes, we propose that excitotoxic mechanisms may play a role in the pathogenesis of TSE neurodegenerative diseases. The similarity in pathogenesis of the neurodegenerative processes in excitotoxicity compared to TSE diseases also implies that neuroprotective strategies against excitotoxicity may also be effective against TSEs.
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Affiliation(s)
- A C Scallet
- Division of Neurotoxicology, Food and Drug Administration, Jefferson, Arkansas 72079-9502, USA.
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35
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Abstract
Domoic acid is a shellfish toxin which produces gastrointestinal distress, followed by neurological symptoms such as headache, confusion, disorientation and severe deficits in short-term memory. Domoic acid is an amino acid which contains three carboxylic groups, and one imino group, and its solubility, rate of absorption, and elimination would vary depending on the protonation of these groups at different pH's. We propose that domoic acid toxicity varies with pH of administered domoic acid solution. Domoic acid toxicity was measured in mice as the onset times for scratching behaviour, seizure activity, and death, after the intraperitoneal administration of domoic acid at different pH's. Results of the present study show that the scratching behaviour, seizure activity, and death, occurred at 12, 40, and 55 min, after intraperitoneal administration of domoic acid at pH 3.7. Apparently, the onset times for three types of behaviours were relatively long, and well separated from each other. Domoic acid toxicity was lowest at pH 3.7, and highest at pH 7.4, with intermediate toxicity at other pH's. The onset time of scratching behaviour was not influenced by pH of domoic acid solution at three different doses. In contrast, the onset times for seizure activity, and death were significantly affected by pH of domoic acid, toxicity being higher at pH 7.4 than at pH 3.7. The pH effect on domoic acid toxicity diminished as the dose of domoic acid was increased. In fact, at 14.5 mg/kg domoic acid toxicity was similar at both pH's of 3.7 and 7.4. It is concluded that in vivo toxicity of domoic acid varies depending on pH of the administered solution. The differential toxicity of domoic acid at different pH may be related to its solubility, rate of absorption, and elimination, depending on the degree of protonation of domoic acid molecule. Domoic acid toxicity would also vary depending on the age of animal, receptor sensitivity and density in different regions of brain.
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Affiliation(s)
- M S Nijjar
- Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada
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Schmued LC, Scallet AC, Slikker W. Domoic acid-induced neuronal degeneration in the primate forebrain revealed by degeneration specific histochemistry. Brain Res 1995; 695:64-70. [PMID: 8574649 DOI: 10.1016/0006-8993(95)00799-v] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Domoic acid is a potent excitotoxin produced by diatoms which is subsequently passed along the marine food chain. Its chemical structure and toxicological properties are similar to kainic acid. Like kainic acid, exposure results in extensive hippocampal degeneration. The effect of domoic acid on other primate brain structures, however, is less resolved. In an attempt to clarify this issue, the present study applied a degeneration specific histochemical technique (de Olmos' cupric-silver method) to reveal degeneration within the brains of domoic acid-dosed cynomolgus monkeys. Degenerating neuronal cell bodies and terminals were found not only within the hippocampus, but also within a number of other 'limbic' structures including the entorhinal cortex, the subiculum, the piriform cortex, the lateral septum, and the dorsal lateral nucleus of the thalamus. Although the hippocampus is a component of the original limbic circuit of Papez, other components such as the mammillary bodies, the anterior nucleus of the thalamus and the cingulate cortex contained no degeneration, while a number of more recently documented efferent targets of the hippocampal formation revealed extensive degeneration. The pattern of degeneration generally correlated with those regions containing high densities of kainate receptors.
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Affiliation(s)
- L C Schmued
- Division of Neurotoxicology, Food and Drug Administration, Jefferson, AR 72079-9502, USA
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Smith DS, Kitts DD. A competitive enzyme-linked immunoassay for domoic acid determination in human body fluids. Food Chem Toxicol 1994; 32:1147-54. [PMID: 7813986 DOI: 10.1016/0278-6915(94)90130-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A polyclonal antiserum was raised in mice against domoic acid. Two of three immunogens consisted of domoic acid coupled to ovalbumin (OVA) and keyhole limpet haemocyanin at molar ratios of 47:1 and 44:1, respectively using a carbodiimide reaction. Titres of both antisera exceeded 1/35,000 against domoic acid coupled to the non-relevant carrier. Domoic acid was also conjugated to bovine serum albumin at a molar ratio of 30:1 using N-hydroxysuccinimidyl-4-azidobenzoate, a photoreactive compound. This immunogen, however, produced no measurable serum titres against domoic acid. The antiserum produced against the OVA conjugate displayed the highest affinity for free domoic acid in competitive enzyme-linked immunosorbent assay (ELISA). Furthermore, this antiserum preparation did not significantly cross-react with glutamic acid, aspartic acid, the structural analogue kainic acid, or the paralytic shellfish toxin, saxitoxin. The competitive ELISA was used to quantify domoic acid concentrations in human body fluids spiked with pure domoate. The lower limits of accurate domoic acid determinations in competitive ELISA were 0.2 micrograms/ml in urine, 0.25 micrograms/ml in plasma and 10 micrograms/ml in milk. It was concluded that the competitive ELISA described herein could be used to quantitate directly the concentration of domoic acid in the body fluids of individuals with amnesic shellfish poisoning.
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Affiliation(s)
- D S Smith
- Department of Food Sciences, University of British Columbia, Vancouver, Canada
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38
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Abstract
Marine and terrestrial food sources are susceptible to contamination by various industrial chemicals and microbial pathogens. Both types of hazard are amenable to regulatory assessment using a single toxicology data base, along with some knowledge of contaminant levels and consumption figures for food. On the other hand, regulatory problems persist with acutely toxic naturally occurring phycotoxins, which may accumulate unpredictably to toxic levels in seafood. However, a scarce supply of pure toxin often precludes the availability of acceptable toxicology studies describing their biological effects. An exception to this situation is domoic acid, a neurotoxin phycotoxin that produced numerous cases of severe human intoxication which demanded extensive toxicological study. This paper describes a series of ongoing studies initiated in the wake of the outbreak of domoic acid toxicity that occurred in 1987 in Eastern Canada.
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Affiliation(s)
- F Iverson
- Toxicology Research Division, Bureau of Chemical Safety, Health Canada, Ottawa
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Scallet AC, Binienda Z, Caputo FA, Hall S, Paule MG, Rountree RL, Schmued L, Sobotka T, Slikker W. Domoic acid-treated cynomolgus monkeys (M. fascicularis): effects of dose on hippocampal neuronal and terminal degeneration. Brain Res 1993; 627:307-13. [PMID: 8298975 DOI: 10.1016/0006-8993(93)90335-k] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Domoic acid is a tricarboxylic amino acid (structurally related to kainic acid and glutamic acid) that is found in the environment as a contaminant of some seafood. To determine the nature of any neurological damage caused by domoate, as well as the minimum neurotoxic dose, juvenile and adult monkeys were dosed intravenously with domoate at one of a range of doses from 0.25 to 4 mg/kg. When animals were perfused one week later, histochemical staining using a silver method to reveal degenerating axons and cell bodies showed two distinct types of hippocampal lesions. One lesion, termed 'Type A', was a small focal area of silver grains restricted to CA2 stratum lucidum, the site of greatest kainic acid receptor concentration in the brain. Type A lesions occurred over a dose range of 0.5 to 2.0 mg/kg in juvenile animals and 0.5 to 1.0 mg/kg in adult animals. No mortality occurred in any of the juvenile monkeys, but one juvenile animal that received 4.0 mg/kg sustained a second type of lesion, termed 'Type B', characterized by widespread damage to pyramidal neurons and axon terminals of CA4, CA3, CA2, CA1, and subiculum subfields of the hippocampus. Doses of more than 1.0 mg/kg in the adult monkeys either proved lethal or resulted in Type B lesions. Induction of c-fos protein had occurred in the hippocampal dentate gyrus and CA1 regions of moribund animals perfused within hours of their initial dose.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A C Scallet
- Division of Neurotoxicology, FDA/National Center for Toxicological Research, Jefferson, AR 72079
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Masliah E, Achim CL, Ge N, DeTeresa R, Terry RD, Wiley CA. Spectrum of human immunodeficiency virus-associated neocortical damage. Ann Neurol 1992; 32:321-9. [PMID: 1416802 DOI: 10.1002/ana.410320304] [Citation(s) in RCA: 279] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A spectrum of neurocognitive defects, termed human immunodeficiency virus type 1 (HIV-1)-associated cognitive/motor complex, has been described in patients with acquired immunodeficiency syndrome (AIDS). AIDS dementia complex (ADC) is a severe form of this disease seen in 20 to 30% of terminally ill patients. The etiology of this complex is distinct from commonly observed opportunistic infections seen in brains of patients with AIDS and has been attributed to HIV infection within the brain. At autopsy, the brains of patients with ADC contain numerous HIV-infected macrophages/microglia with prominent subcortical damage, together termed HIV encephalitis. We retrospectively analyzed all 107 brains from a three-year period (1988-1990) of AIDS autopsies using immunocytochemistry to detect HIV. Rather than breaking into distinct groups of HIV encephalitis versus non-HIV encephalitis, the specimens revealed a spectrum of severity of HIV infection. Although only 16% of the brains showed the histological hallmarks of HIV encephalitis, more than 50% of the autopsies showed moderate to severe HIV infection. In a subset of 23 AIDS autopsies during which short postmortem times and absence of significant opportunistic infection permitted quantitative analysis of dendritic and synaptic complexities, we identified a strong correlation between neocortical dendritic and presynaptic damage and abundance of HIV envelope protein in the neocortical gray and deep white matter. This correlation suggests that the presence of HIV-1 in the neocortex may be responsible by direct or indirect mechanisms for dendritic and synaptic damage.
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Affiliation(s)
- E Masliah
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla 92093-0624
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