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Campbell MA, Murphy SR, Klasing SA, Niknam Y, Iyer P, Stanton B, Zeise L. Life Course Considerations in Environmental Health: Developmental Neurotoxicity of Domoic Acid at Doses Below Acute Effect Levels in Adult Humans. Birth Defects Res 2024; 116:e2419. [PMID: 39670542 PMCID: PMC11639046 DOI: 10.1002/bdr2.2419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Revised: 11/08/2024] [Accepted: 11/14/2024] [Indexed: 12/14/2024]
Abstract
BACKGROUND Current US federal action levels for domoic acid (DA) in seafood are based on acute toxicity observed in exposed adult humans. Life course considerations have not been incorporated. The potential for developmental neurotoxicity (DNT) at permissible DA levels has previously been noted, but not methodically assessed. METHODS Studies of DNT following DA exposure in experimental and wild animals were identified through a comprehensive search strategy. Evidence from papers meeting inclusion criteria was evaluated for specific outcomes reported for doses at which adverse effects were observed. Exposure levels associated with DNT were compared with those known to cause adult toxicity. The findings are discussed in the context of the well-characterized mechanism of DA neurotoxicity, as well as the toxicokinetics of DA across species and life stages. CONCLUSIONS DNT outcomes were reported with a no observed adverse effect level (NOAEL) 10 times lower than the NOAEL of 0.75 mg DA/kg for acute effects in adults. Apart from reviewing current regulatory action levels, public health outreach messaging to health care professionals and sensitive populations, such as pregnant or breastfeeding women, should be considered as a means of increasing awareness about risk for DNT from consumption of potentially DA-contaminated seafood.
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Affiliation(s)
- Marlissa A. Campbell
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Shannon R. Murphy
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Susan A. Klasing
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Yassaman Niknam
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Poorni Iyer
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Beckye Stanton
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
| | - Lauren Zeise
- Office of Environmental Health Hazard Assessment, California Environmental Protection AgencySacramentoCaliforniaUSA
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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 PMCID: PMC8939048 DOI: 10.1016/j.pharmthera.2021.107865] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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Sasaki T, Saito H, Hiradate Y, Hara K, Tanemura K. Behavioural effects in mice orally exposed to domoic acid or ibotenic acid are influenced by developmental stages and sex differences. Biochem Biophys Res Commun 2021; 558:175-182. [PMID: 33932777 DOI: 10.1016/j.bbrc.2021.04.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/19/2021] [Indexed: 10/21/2022]
Abstract
The structure of the brain is dramatically altered during the critical period. Physiological substances (neurotransmitters, hormones, etc.) in the body fluctuate significantly before and after sexual maturation. Therefore, the effect of chemical exposure on the central nervous system often differs depending on the developmental stage and sex. We aimed to compare the behavioural effects that emerged from the administration of chemicals to mice of different life stages (immature or mature) and different sex (male or female). We administered mice with domoic acid (DA), a marine poison, and ibotenic acid (IA), found in poisonous mushrooms. These excitatory amino acids act as agonists for glutamate and are potent neurotoxins. Interestingly, the behavioural effects of these chemicals were completely different. Following DA administration, we observed memory deficits only in groups of male mice treated at maturity. Following IA administration, we observed deviations in emotional behaviour in groups of male mice treated at both immaturity and maturity. In contrast, few characteristic changes were detected in all groups of females. Our results support the theory that the behavioural effects of chemical administration vary considerably with developmental stages and sex. In conclusion, our findings promote better understanding of individual differences in excitatory chemical-induced neurotoxicity and provide evidence for future risk strategies and treatments.
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Affiliation(s)
- Takahiro Sasaki
- Laboratory of Animal Reproduction and Development, Graduate School of Agricultural, Science, Tohoku University, 468-1 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Hirokatsu Saito
- Division of Cellular and Molecular Toxicology, Center for Biological Safety and Research, National Institute of Health Sciences, 3-25-26 Tono-machi, Kawasaki-ku, Kawasaki, Kanagawa, 210-9501, Japan
| | - Yuuki Hiradate
- Laboratory of Animal Reproduction and Development, Graduate School of Agricultural, Science, Tohoku University, 468-1 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Kenshiro Hara
- Laboratory of Animal Reproduction and Development, Graduate School of Agricultural, Science, Tohoku University, 468-1 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan
| | - Kentaro Tanemura
- Laboratory of Animal Reproduction and Development, Graduate School of Agricultural, Science, Tohoku University, 468-1 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan.
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Grattan LM, Kaddis L, Tracy JK, Morris JG. Long Term Memory Outcome of Repetitive, Low-Level Dietary Exposure to Domoic Acid in Native Americans. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18083955. [PMID: 33918677 PMCID: PMC8069405 DOI: 10.3390/ijerph18083955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/24/2022]
Abstract
Domoic acid (DA) is a marine-based neurotoxin that, if ingested via tainted shellfish, is associated with Amnesic Shellfish Poisoning (ASP). These acute effects of elevated DA exposure in humans have been well described. In contrast, the long-term impacts of lower level, repetitive, presumably safe doses of DA (less than 20 ppm) are minimally known. Since Native Americans (NA) residing in coastal communities of the Pacific NW United States are particularly vulnerable to DA exposure, this study focuses on the long-term, 8-year memory outcome associated with their repeated dietary consumption of the neurotoxin. Measures of razor clam consumption, memory, clerical speed and accuracy, and depression were administered over eight years to 500 randomly selected adult NA men and women ages 18–64. Data were analyzed using GEE analyses taking into consideration the year of study, demographic factors, and instrumentation in examining the association between dietary exposure and outcomes. Findings indicated a significant but small decline in total recall memory within the context of otherwise stable clerical speed and accuracy and depression scores. There is reason to believe that a continuum of memory difficulties may be associated with DA exposure, rather than a unitary ASP syndrome.
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Affiliation(s)
- Lynn M. Grattan
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence:
| | - Laura Kaddis
- Department of Otorhinolaryngology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - J. Kate Tracy
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - John Glenn Morris
- Department of Medicine, College of Medicine, Emergency Pathogens Institute, University of Florida, Gainesville, FL 32610, USA;
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Panlilio JM, Aluru N, Hahn ME. Developmental Neurotoxicity of the Harmful Algal Bloom Toxin Domoic Acid: Cellular and Molecular Mechanisms Underlying Altered Behavior in the Zebrafish Model. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:117002. [PMID: 33147070 PMCID: PMC7641300 DOI: 10.1289/ehp6652] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND Harmful algal blooms (HABs) produce potent neurotoxins that threaten human health, but current regulations may not be protective of sensitive populations. Early life exposure to low levels of the HAB toxin domoic acid (DomA) produces long-lasting behavioral deficits in rodent and primate models; however, the mechanisms involved are unknown. The zebrafish is a powerful in vivo vertebrate model system for exploring cellular processes during development and thus may help to elucidate mechanisms of DomA developmental neurotoxicity. OBJECTIVES We used the zebrafish model to investigate how low doses of DomA affect the developing nervous system, including windows of susceptibility to DomA exposure, structural and molecular changes in the nervous system, and the link to behavioral alterations. METHODS To identify potential windows of susceptibility, DomA (0.09-0.18 ng) was delivered to zebrafish through caudal vein microinjection during distinct periods in early neurodevelopment. Following exposure, structural and molecular targets were identified using live imaging of transgenic fish and RNA sequencing. To assess the functional consequences of exposures, we quantified startle behavior in response to acoustic/vibrational stimuli. RESULTS Larvae exposed to DomA at 2 d postfertilization (dpf), but not at 1 or 4 dpf, showed consistent deficits in startle behavior at 7 dpf, including lower responsiveness and altered kinematics. Similarly, myelination in the spinal cord was disorganized after exposure at 2 dpf but not 1 or 4 dpf. Time-lapse imaging revealed disruption of the initial stages of myelination. DomA exposure at 2 dpf down-regulated genes required for maintaining myelin structure and the axonal cytoskeleton. DISCUSSION These results in zebrafish reveal a developmental window of susceptibility to DomA-induced behavioral deficits and identify altered gene expression and disrupted myelin structure as possible mechanisms. The results establish a zebrafish model for investigating the mechanisms of developmental DomA toxicity, including effects with potential relevance to exposed sensitive human populations. https://doi.org/10.1289/EHP6652.
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Affiliation(s)
- Jennifer M. Panlilio
- Biology Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, Massachusetts, USA
- Massachusetts Institute of Technology (MIT)–WHOI Joint Graduate Program in Oceanography and Oceanographic Engineering, Department of Earth, Atmospheric and Planetary Sciences, MIT, Cambridge, Massachusetts, USA
- Woods Hole Center for Oceans and Human Health, WHOI, Woods Hole, Massachusetts, USA
| | - Neelakanteswar Aluru
- Biology Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, Massachusetts, USA
- Woods Hole Center for Oceans and Human Health, WHOI, Woods Hole, Massachusetts, USA
| | - Mark E. Hahn
- Biology Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, Massachusetts, USA
- Woods Hole Center for Oceans and Human Health, WHOI, Woods Hole, Massachusetts, USA
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Burbacher TM, Grant KS, Petroff R, Shum S, Crouthamel B, Stanley C, McKain N, Jing J, Isoherranen N. 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 PMCID: PMC6408264 DOI: 10.1016/j.ntt.2019.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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Affiliation(s)
- 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; Washington National Primate Research Center, Seattle, WA, USA.
| | - Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, Seattle, WA, USA
| | - Rebekah Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brenda Crouthamel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, Seattle, WA, USA
| | - Courtney Stanley
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Noelle McKain
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, 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
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7
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Demars F, Clark K, Wyeth MS, Abrams E, Buckmaster PS. A single subconvulsant dose of domoic acid at mid-gestation does not cause temporal lobe epilepsy in mice. Neurotoxicology 2018; 66:128-137. [PMID: 29625197 PMCID: PMC5940543 DOI: 10.1016/j.neuro.2018.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/28/2018] [Accepted: 04/02/2018] [Indexed: 11/19/2022]
Abstract
Harmful blooms of domoic acid (DA)-producing algae are a problem in oceans worldwide. DA is a potent glutamate receptor agonist that can cause status epilepticus and in survivors, temporal lobe epilepsy. In mice, one-time low-dose in utero exposure to DA was reported to cause hippocampal damage and epileptiform activity, leading to the hypothesis that unrecognized exposure to DA from contaminated seafood in pregnant women can damage the fetal hippocampus and initiate temporal lobe epileptogenesis. However, development of epilepsy (i.e., spontaneous recurrent seizures) has not been tested. In the present study, long-term seizure monitoring and histology was used to test for temporal lobe epilepsy following prenatal exposure to DA. In Experiment One, the previous study's in utero DA treatment protocol was replicated, including use of the CD-1 mouse strain. Afterward, mice were video-monitored for convulsive seizures from 2 to 6 months old. None of the CD-1 mice treated in utero with vehicle or DA was observed to experience spontaneous convulsive seizures. After seizure monitoring, mice were evaluated for pathological evidence of temporal lobe epilepsy. None of the mice treated in utero with DA displayed the hilar neuron loss that occurs in patients with temporal lobe epilepsy and in the mouse pilocarpine model of temporal lobe epilepsy. In Experiment Two, a higher dose of DA was administered to pregnant FVB mice. FVB mice were tested as a potentially more sensitive strain, because they have a lower seizure threshold, and some females spontaneously develop epilepsy. Female offspring were monitored with continuous video and telemetric bilateral hippocampal local field potential recording at 1-11 months old. A similar proportion of vehicle- and DA-treated female FVB mice spontaneously developed epilepsy, beginning in the fourth month of life. Average seizure frequency and duration were similar in both groups. Seizure frequency was lower than that of positive-control pilocarpine-treated mice, but seizure duration was similar. None of the mice treated in utero with vehicle or DA displayed hilar neuron loss or intense mossy fiber sprouting, a form of aberrant synaptic reorganization that develops in patients with temporal lobe epilepsy and in pilocarpine-treated mice. FVB mice that developed epilepsy (vehicle- and DA-treated) displayed mild mossy fiber sprouting. Results of this study suggest that a single subconvulsive dose of DA at mid-gestation does not cause temporal lobe epilepsy in mice.
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Affiliation(s)
- Fanny Demars
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; VetAgro Sup, School of Veterinary Medicine, Lyon, France; Paris Descartes University, Paris, France
| | - Kristen Clark
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, United States
| | - Megan S Wyeth
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States
| | - Emily Abrams
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States
| | - Paul S Buckmaster
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States.
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Sunkaria A, Yadav A, Bhardwaj S, Sandhir R. Postnatal Proteasome Inhibition Promotes Amyloid-β Aggregation in Hippocampus and Impairs Spatial Learning in Adult Mice. Neuroscience 2017; 367:47-59. [DOI: 10.1016/j.neuroscience.2017.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/09/2017] [Accepted: 10/16/2017] [Indexed: 12/13/2022]
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Lahvis GP. What California sea lions exposed to domoic acid might teach us about autism: lessons for predictive and preventive medicine. EPMA J 2017; 8:229-235. [PMID: 29021833 PMCID: PMC5607054 DOI: 10.1007/s13167-017-0118-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/22/2017] [Indexed: 10/18/2022]
Abstract
Autism spectrum disorder (ASD) shares many biological and behavioral similarities with the deleterious effects of domoic acid (DA) exposure. DA is produced by marine algae and most commonly by species of Pseudo-nitzschia. Humans and marine mammals can be exposed to DA when they consume whole fish or shellfish. The mammalian fetus is highly sensitive to the deleterious effects of DA exposure. Both ASD and exposures to toxic levels of DA feature repetitive behaviors, challenges with social interaction, and seizures. They can also share a commonality in brain anatomy and function, particularly the balance between excitatory and inhibitory mechanisms. The current article is relevant to predictive, preventive, and personalized medicine for three reasons. First, shellfish consumption may be a risk factor for ASD and the regulatory limit for DA should be adjusted to prevent this possibility. Human contributions to increased algal production of DA in coastal waters should be identified and reduced. Second, evaluations of sentinel species wild and free-roaming in the environment, though typically outside the purview of biomedical research, should be much more fully employed to gain insights to risk factors for human disease. To better identify and prevent disease, biomedical researchers should study wild populations. Third, studies of DA exposure highlight the possibility that glutamate additives to processed foods may also have deleterious impacts on human brain development and behavior.
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Affiliation(s)
- Garet Paul Lahvis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239 USA
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10
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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: 1.6] [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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11
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Zuloaga DG, Lahvis GP, Mills B, Pearce HL, Turner J, Raber J. Fetal domoic acid exposure affects lateral amygdala neurons, diminishes social investigation and alters sensory-motor gating. Neurotoxicology 2016; 53:132-140. [PMID: 26797589 PMCID: PMC5929993 DOI: 10.1016/j.neuro.2016.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 01/01/2023]
Abstract
Domoic acid (DA) is an algal neurotoxin that accumulates in marine fish and shellfish. DA can move across the placenta and concentrate in amniotic fluid, which can be swallowed during late gestation. DA also transfers to infants via milk. Preclinical studies to determine effects of developmental DA expose have primarily involved DA exposure during the postnatal period and little is known about late CNS effects following prenatal DA. In the present study, we tested the hypothesis that prenatal exposure of FVB mice to low levels of DA would result in diminished social interaction and sensory motor gating associated with alterations in parvalbumin immunoreactivity in relevant brain regions undergoing development during and following DA exposure. In addition to parvalbumin, we stained with NeuN for a neuronal specific nuclear protein to determine if neuronal loss followed prenatal DA exposure. A single moderate dose of DA administered during gestation produces diminishes social investigation and alters sensorimotor gating, behavioral effects more pronounced in males than females. These behavioral changes were associated with discrete alterations in the parvalbumin-positive subtype of GABAergic neurons in the dentate gyrus and lateral amygdala.
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Affiliation(s)
- D G Zuloaga
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - G P Lahvis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States.
| | - B Mills
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - H L Pearce
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - J Turner
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - J Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, United States.
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12
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Levin ED, Wells C, Johnson JE, Rezvani AH, Bymaster FP, Rose JE. Amitifadine, a triple monoamine re-uptake inhibitor, reduces nicotine self-administration in female rats. Eur J Pharmacol 2015; 764:30-37. [PMID: 26101069 DOI: 10.1016/j.ejphar.2015.06.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 05/28/2015] [Accepted: 06/18/2015] [Indexed: 10/23/2022]
Abstract
A wider diversity of drug treatments to aid smoking cessation is needed to help tailor the most efficacious treatment for different types of smokers. This study was conducted to determine whether amitifadine, which inhibits re-uptake of dopamine, norepinephrine and serotonin, would decrease nicotine self-administration at doses that do not cause adverse side effects. Adult female Sprague-Dawley rats were trained to self-administer nicotine intravenous (IV) and were given acute doses of amitifadine in a repeated measures counterbalanced design. Effects of amitifadine on locomotor activity and food motivated responding were also evaluated. Chronic amitifadine effects were also examined. The 30 mg/kg amitifadine dose significantly reduced nicotine self-administration. The 5 and 10 mg/kg doses reduced nicotine self-administration during the first 15 min of the session when the greatest amount of nicotine was self-administered. The 30 mg/kg amitifadine dose, but not the lower doses caused a significant reduction in locomotor activity averaged over the one-hour session and reduced food motivated responding. The 10 mg/kg dose caused hypoactivity at the beginning of the session, but 5 mg/kg did not cause any hypoactivity. The effects of chronic amitifadine treatment (10 mg/kg) over the course of 15 sessions was also determined. Amitifadine caused a significant reduction in nicotine self-administration, which was not seen to diminish over two consecutive weeks of treatment and a week after enforced abstinence. Amitifadine significantly reduced nicotine self-administration. This prompts further research to determine if amitifadine might be an effective treatment for smoking cessation.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
| | - Corinne Wells
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Joshua E Johnson
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Amir H Rezvani
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
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Levin ED. Learning about cognition risk with the radial-arm maze in the developmental neurotoxicology battery. Neurotoxicol Teratol 2015; 52:88-92. [PMID: 26013674 DOI: 10.1016/j.ntt.2015.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/21/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
Cognitive dysfunction has been found in epidemiological studies to be among the most sensitive impairments associated with developmental exposure to a variety of environmental contaminants from heavy metals to polyhalogenated hydrocarbons and pesticides. These chemicals have been also shown to impair cognitive function after developmental exposure in experimental animal models. The radial-arm maze (RAM) has proven to be a sensitive and reliable way to assess both learning and memory in a variety of species, most often in rats and mice. The RAM is a very adaptable test method that takes advantage of rodents' instinct to explore new places in the environment to forage. That is, rodents do not need to be trained to run through the maze; they will normally do this from the initial session of testing. Training with differential reinforcement for arm choices provides a more rigorous test of learning and memory. The RAM is quite adaptable for assessing various aspects of cognition. Although the RAM has been mostly used to assess spatial learning and memory, it can be configured to assess non-spatial memory as well. Both working and reference memory can be easily distinguished. The RAM can be run with both appetitive (food reinforced) and aversive (water escape) motivators. The RAM has been found to be sensitive to a wide variety of developmental toxicants including heavy metals such as mercury and pesticides such as chlorpyrifos. There is an extremely rich literature especially with rats showing the effects of many types of brain lesions and drug effects so that the participation of a wide variety of neural systems in RAM performance is known. These systems, notably the hippocampus and frontal cortex, and acetylcholine and glutamate neurotransmitter systems, are the same neural systems that have been shown in humans to be critical for learning and memory. This considerably aids the interpretation of neurobehavioral toxicity studies.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA.
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Hiolski EM, Kendrick PS, Frame ER, Myers MS, Bammler TK, Beyer RP, Farin FM, Wilkerson HW, Smith DR, Marcinek DJ, Lefebvre KA. Chronic low-level domoic acid exposure alters gene transcription and impairs mitochondrial function in the CNS. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 155:151-9. [PMID: 25033243 PMCID: PMC4139102 DOI: 10.1016/j.aquatox.2014.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/09/2014] [Accepted: 06/13/2014] [Indexed: 05/10/2023]
Abstract
Domoic acid is an algal-derived seafood toxin that functions as a glutamate agonist and exerts excitotoxicity via overstimulation of glutamate receptors (AMPA, NMDA) in the central nervous system (CNS). At high (symptomatic) doses, domoic acid is well-known to cause seizures, brain lesions and memory loss; however, a significant knowledge gap exists regarding the health impacts of repeated low-level (asymptomatic) exposure. Here, we investigated the impacts of low-level repetitive domoic acid exposure on gene transcription and mitochondrial function in the vertebrate CNS using a zebrafish model in order to: (1) identify transcriptional biomarkers of exposure; and (2) examine potential pathophysiology that may occur in the absence of overt excitotoxic symptoms. We found that transcription of genes related to neurological function and development were significantly altered, and that asymptomatic exposure impaired mitochondrial function. Interestingly, the transcriptome response was highly variable across the exposure duration (36 weeks), with little to no overlap of specific genes across the six exposure time points (2, 6, 12, 18, 24, and 36 weeks). Moreover, there were no apparent similarities at any time point with the gene transcriptome profile exhibited by the glud1 mouse model of chronic moderate excess glutamate release. These results suggest that although the fundamental mechanisms of toxicity may be similar, gene transcriptome responses to domoic acid exposure do not extrapolate well between different exposure durations. However, the observed impairment of mitochondrial function based on respiration rates and mitochondrial protein content suggests that repetitive low-level exposure does have fundamental cellular level impacts that could contribute to chronic health consequences.
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Affiliation(s)
- Emma M Hiolski
- University of California, Santa Cruz, CA 95064, United States.
| | | | - Elizabeth R Frame
- NOAA Northwest Fisheries Science Center, Seattle, WA 98112, United States.
| | - Mark S Myers
- University of Washington, Seattle, WA 98112, United States.
| | - Theo K Bammler
- University of Washington, Seattle, WA 98112, United States.
| | | | | | | | - Donald R Smith
- University of California, Santa Cruz, CA 95064, United States.
| | | | - Kathi A Lefebvre
- NOAA Northwest Fisheries Science Center, Seattle, WA 98112, United States.
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Munday R, Reeve J. Risk assessment of shellfish toxins. Toxins (Basel) 2013; 5:2109-37. [PMID: 24226039 PMCID: PMC3847717 DOI: 10.3390/toxins5112109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/23/2013] [Accepted: 10/30/2013] [Indexed: 01/24/2023] Open
Abstract
Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.
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Affiliation(s)
- Rex Munday
- AgResearch Ltd, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +64-7-838-5138; Fax: +64-7-838-5012
| | - John Reeve
- Ministry of Primary Industries, PO Box 2526, Wellington, New Zealand; E-Mail:
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Maucher Fuquay J, Muha N, Wang Z, Ramsdell JS. Elimination Kinetics of Domoic Acid from the Brain and Cerebrospinal Fluid of the Pregnant Rat. Chem Res Toxicol 2012; 25:2805-9. [DOI: 10.1021/tx300434s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jennifer Maucher Fuquay
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - Noah Muha
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - Zhihong Wang
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - John S. Ramsdell
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
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Postnatal proteasome inhibition induces neurodegeneration and cognitive deficiencies in adult mice: a new model of neurodevelopment syndrome. PLoS One 2011; 6:e28927. [PMID: 22174927 PMCID: PMC3236230 DOI: 10.1371/journal.pone.0028927] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 11/17/2011] [Indexed: 11/19/2022] Open
Abstract
Defects in the ubiquitin-proteasome system have been related to aging and the development of neurodegenerative disease, although the effects of deficient proteasome activity during early postnatal development are poorly understood. Accordingly, we have assessed how proteasome dysfunction during early postnatal development, induced by administering proteasome inhibitors daily during the first 10 days of life, affects the behaviour of adult mice. We found that this regime of exposure to the proteasome inhibitors MG132 or lactacystin did not produce significant behavioural or morphological changes in the first 15 days of life. However, towards the end of the treatment with proteasome inhibitors, there was a loss of mitochondrial markers and activity, and an increase in DNA oxidation. On reaching adulthood, the memory of mice that were injected with proteasome inhibitors postnatally was impaired in hippocampal and amygdala-dependent tasks, and they suffered motor dysfunction and imbalance. These behavioural deficiencies were correlated with neuronal loss in the hippocampus, amygdala and brainstem, and with diminished adult neurogenesis. Accordingly, impairing proteasome activity at early postnatal ages appears to cause morphological and behavioural alterations in adult mice that resemble those associated with certain neurodegenerative diseases and/or syndromes of mental retardation.
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Watanabe KH, Andersen ME, Basu N, Carvan MJ, Crofton KM, King KA, Suñol C, Tiffany-Castiglioni E, Schultz IR. Defining and modeling known adverse outcome pathways: Domoic acid and neuronal signaling as a case study. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:9-21. [PMID: 20963854 DOI: 10.1002/etc.373] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
An adverse outcome pathway (AOP) is a sequence of key events from a molecular-level initiating event and an ensuing cascade of steps to an adverse outcome with population-level significance. To implement a predictive strategy for ecotoxicology, the multiscale nature of an AOP requires computational models to link salient processes (e.g., in chemical uptake, toxicokinetics, toxicodynamics, and population dynamics). A case study with domoic acid was used to demonstrate strategies and enable generic recommendations for developing computational models in an effort to move toward a toxicity testing paradigm focused on toxicity pathway perturbations applicable to ecological risk assessment. Domoic acid, an algal toxin with adverse effects on both wildlife and humans, is a potent agonist for kainate receptors (ionotropic glutamate receptors whose activation leads to the influx of Na(+) and Ca²(+)). Increased Ca²(+) concentrations result in neuronal excitotoxicity and cell death, primarily in the hippocampus, which produces seizures, impairs learning and memory, and alters behavior in some species. Altered neuronal Ca²(+) is a key process in domoic acid toxicity, which can be evaluated in vitro. Furthermore, results of these assays would be amenable to mechanistic modeling for identifying domoic acid concentrations and Ca²(+) perturbations that are normal, adaptive, or clearly toxic. In vitro assays with outputs amenable to measurement in exposed populations can link in vitro to in vivo conditions, and toxicokinetic information will aid in linking in vitro results to the individual organism. Development of an AOP required an iterative process with three important outcomes: a critically reviewed, stressor-specific AOP; identification of key processes suitable for evaluation with in vitro assays; and strategies for model development.
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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: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [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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Tasker RA, Adams-Marriott AL, Shaw CA. New animal models of progressive neurodegeneration: tools for identifying targets in predictive diagnostics and presymptomatic treatment. EPMA J 2010. [PMID: 23199060 PMCID: PMC3405326 DOI: 10.1007/s13167-010-0019-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mental and neurological disorders are increasingly prevalent and constitute a major societal and economic burden worldwide. Many of these diseases and disorders are characterized by progressive deterioration over time, that ultimately results in identifiable symptoms that in turn dictate therapy. Disease-specific symptoms, however, often occur late in the degenerative process. A better understanding of presymptomatic events could allow for the development of new diagnostics and earlier interventions that could slow or stop the disease process. Such studies of progressive neurodegeneration require the use of animal models that are characterized by delayed or slowly developing disease phenotype(s). This brief review describes several examples of such animal models that have recently been developed with relevance to various neurological diseases and disorders, and delineates the potential of such models to aid in predictive diagnosis, early intervention and disease prevention.
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Affiliation(s)
- R Andrew Tasker
- Department of Biomedical Sciences, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI, Canada C1A4P3
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López-Pérez SJ, Ureña-Guerrero ME, Morales-Villagrán A. Monosodium glutamate neonatal treatment as a seizure and excitotoxic model. Brain Res 2010; 1317:246-56. [DOI: 10.1016/j.brainres.2009.12.054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 12/17/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
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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: 18] [Impact Index Per Article: 1.2] [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: 41] [Impact Index Per Article: 2.6] [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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24
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Effects of low dose neonatal domoic acid administration on behavioural and physiological response to mild stress in adult rats. Physiol Behav 2009; 98:53-9. [DOI: 10.1016/j.physbeh.2009.04.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/03/2009] [Accepted: 04/09/2009] [Indexed: 01/17/2023]
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25
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Persistent changes in learning and memory in rats following neonatal treatment with domoic acid. Physiol Behav 2009; 96:505-12. [DOI: 10.1016/j.physbeh.2008.11.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 11/07/2008] [Accepted: 11/13/2008] [Indexed: 11/22/2022]
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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: 47] [Impact Index Per Article: 2.8] [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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Maucher JM, Ramsdell JS. Maternal-fetal transfer of domoic acid in rats at two gestational time points. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:1743-6. [PMID: 18087593 PMCID: PMC2137110 DOI: 10.1289/ehp.10446] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 09/18/2007] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND OBJECTIVES Prenatal exposure to asymptomatic doses of domoic acid (DA) causes learning and memory deficits later in life; therefore, we sought to measure distribution of DA in maternal plasma and brain, prenatal brain, and amniotic fluid 1 hr after exposure, a time frame that normally encompasses acute seizure behavior. METHODS Pregnant rats were given a single intravenous dose of DA (0.6 or 1.6 mg/kg body weight) at either gestational day (GD) 13 or GD20, which correspond to the beginning of rat embryo neurogenesis and the last day of gestation, respectively. Using a direct ELISA, dose-dependent levels of DA were detected in each sample matrix tested. RESULTS An average of 6.6 and 14 ng DA/g brain tissue was found in GD13 and GD20 prenatal rats, respectively. Brain concentrations of DA in the GD13 prenates were identical to amniotic fluid levels, consistent with no restriction for DA to enter the GD13 prenatal brain. At GD20 the prenatal brain contained half the concentration of DA in the amniotic fluid, and was approximately half that found in the brain of the dams. After 1 hr, fetal brain and amniotic fluid contained between 1 and 5% of DA found in the maternal circulation. The amniotic fluid levels of DA in this study were also within the same range measured in stranded California sea lions that showed reproductive failure. CONCLUSIONS DA crosses the placenta, enters brain tissue of prenates, and accumulates in the amniotic fluid. Amniotic fluid appears to be a useful fluid to monitor DA exposure.
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Affiliation(s)
| | - John S. Ramsdell
- Address correspondence to J.S. Ramsdell, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412 USA. Telephone: (843) 762-8910. Fax: (843) 762-8700. E-mail:
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Tiedeken JA, Ramsdell JS. Embryonic exposure to domoic Acid increases the susceptibility of zebrafish larvae to the chemical convulsant pentylenetetrazole. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:1547-52. [PMID: 18007982 PMCID: PMC2072828 DOI: 10.1289/ehp.10344] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 08/02/2007] [Indexed: 05/20/2023]
Abstract
BACKGROUND Domoic acid (DA) is a neurotoxin produced by diatoms of the genus Pseudo-nitzschia that targets the limbic system to induce tonic-clonic seizures and memory impairment. In utero DA exposure of mice leads to a reduction in seizure threshold to subsequent DA exposures in mid-postnatal life, and similar studies have shown neurotoxic effects in rats that were delayed until adolescence. OBJECTIVE We used in ovo microinjection of zebrafish (Danio rerio) to characterize the effect of embryonic exposure of DA on seizure-inducing agents later in life as an alternative species model to screen environmental contaminants that might induce a fetal-originating adult disease. METHODS Embryos were microinjected within hours of fertilization to DA concentrations ranging from 0.12 to 1.26 ng/mg egg weight. Seven days later, the larval animals were characterized for sensitivity to the chemical convulsant pentylenetetrazole (PTZ), an agent that is well-defined in laboratory rodents and, more recently, in zebrafish. RESULTS In ovo DA exposure, most significantly at 0.4 ng/mg, reduces the latency time until first PTZ seizure in larval fish and increases the severity of seizures as determined by seizure stage and movement parameters. The interaction between in ovo DA exposure and PTZ caused seizure behaviors to individually asymptomatic doses of PTZ (1.0 and 1.25 mM) and DA (0.13 and 0.22 ng/mg). CONCLUSION These studies demonstrate that in ovo exposure to DA reduces the threshold to chemically induced seizures in larval fish and increases the severity of seizure behavior in a manner that is consistent with in utero studies of laboratory rodents.
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Affiliation(s)
| | - John S. Ramsdell
- Address correspondence to J.S. Ramsdell, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Rd., Charleston, SC 29412 USA. Telephone: (843) 762-8910. Fax: (843) 762-8700. E-mail:
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Bernard PB, Macdonald DS, Gill DA, Ryan CL, Tasker RA. Hippocampal mossy fiber sprouting and elevated trkB receptor expression following systemic administration of low dose domoic acid during neonatal development. Hippocampus 2007; 17:1121-33. [PMID: 17636548 DOI: 10.1002/hipo.20342] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We have previously reported that serial systemic injections of low-dose (subconvulsive) domoic acid (DOM) during early postnatal development produces changes in both behavior and hippocampal cytoarchitecture in aged rats (17 months) that are similar to those seen in existing animal models of temporal lobe epilepsy. Herein we report further hippocampal changes, consisting of mossy fiber sprouting and associated changes in the trkB receptor population in young adult (3 months) rats, and further, report that these changes show regional variation throughout the septo-temporal axis of the hippocampus. Groups of Sprague Dawley rat pups were injected daily from postnatal day 8-14 with either saline (n = 23) or 20 microg/kg DOM (n = 25), tested for key indicators of neonatal neurobehavioral development, and then left undisturbed until approximately 90 days of age, at which time brain tissue was removed, hippocampi were dissected, fixed and processed using either Timm's stain to visualize hippocampal mossy fiber sprouting (MFS) or trkB immunohistochemistry to visualize full length trkB receptors. Multiple sections from dorsal, mid, and ventral hippocampus were analyzed separately and all measures were conducted using image analysis software. The results indicate significant increases in MFS in the inner molecular layer in treated animals with corresponding changes in trkB receptor density. Further we identified significant increases in trkB receptor density in the hilus of the dentate gyrus and area CA3 and report increased mossy fiber terminal density in the stratum lucidum in treated rats. The magnitude of these changes differed between sections from dorsal, mid, and ventral hippocampus. We conclude that low dose neonatal DOM produces cytoarchitectural changes indicative of abnormal development and/or synaptic plasticity that are progressive with age and show regional variation within the hippocampal formation.
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Affiliation(s)
- Paul B Bernard
- Department of Biomedical Sciences, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
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