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Louzao MC, Vilariño N, Vale C, Costas C, Cao A, Raposo-Garcia S, Vieytes MR, Botana LM. Current Trends and New Challenges in Marine Phycotoxins. Mar Drugs 2022; 20:md20030198. [PMID: 35323497 PMCID: PMC8950113 DOI: 10.3390/md20030198] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 02/04/2023] Open
Abstract
Marine phycotoxins are a multiplicity of bioactive compounds which are produced by microalgae and bioaccumulate in the marine food web. Phycotoxins affect the ecosystem, pose a threat to human health, and have important economic effects on aquaculture and tourism worldwide. However, human health and food safety have been the primary concerns when considering the impacts of phycotoxins. Phycotoxins toxicity information, often used to set regulatory limits for these toxins in shellfish, lacks traceability of toxicity values highlighting the need for predefined toxicological criteria. Toxicity data together with adequate detection methods for monitoring procedures are crucial to protect human health. However, despite technological advances, there are still methodological uncertainties and high demand for universal phycotoxin detectors. This review focuses on these topics, including uncertainties of climate change, providing an overview of the current information as well as future perspectives.
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Affiliation(s)
- Maria Carmen Louzao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
| | - Natalia Vilariño
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Carmen Vale
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Celia Costas
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Alejandro Cao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Sandra Raposo-Garcia
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Mercedes R. Vieytes
- Departamento de Fisiologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain;
| | - Luis M. Botana
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
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Marine toxin domoic acid induces moderate toxicological response in non-target HepG2 cells. Toxicology 2022; 470:153157. [DOI: 10.1016/j.tox.2022.153157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 11/19/2022]
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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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A human stem cell-derived test system for agents modifying neuronal N-methyl-D-aspartate-type glutamate receptor Ca 2+-signalling. Arch Toxicol 2021; 95:1703-1722. [PMID: 33713149 PMCID: PMC8113295 DOI: 10.1007/s00204-021-03024-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/04/2021] [Indexed: 12/12/2022]
Abstract
Methods to assess neuronal receptor functions are needed in toxicology and for drug development. Human-based test systems that allow studies on glutamate signalling are still scarce. To address this issue, we developed and characterized pluripotent stem cell (PSC)-based neural cultures capable of forming a functional network. Starting from a stably proliferating neuroepithelial stem cell (NESC) population, we generate “mixed cortical cultures” (MCC) within 24 days. Characterization by immunocytochemistry, gene expression profiling and functional tests (multi-electrode arrays) showed that MCC contain various functional neurotransmitter receptors, and in particular, the N-methyl-d-aspartate subtype of ionotropic glutamate receptors (NMDA-R). As this important receptor is found neither on conventional neural cell lines nor on most stem cell-derived neurons, we focused here on the characterization of rapid glutamate-triggered Ca2+ signalling. Changes of the intracellular free calcium ion concentration ([Ca2+]i) were measured by fluorescent imaging as the main endpoint, and a method to evaluate and quantify signals in hundreds of cells at the same time was developed. We observed responses to glutamate in the low µM range. MCC responded to kainate and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and a subpopulation of 50% had functional NMDA-R. The receptor was modulated by Mg2+, Zn2+ and Pb2+ in the expected ways, and various toxicologically relevant agonists (quinolinic acid, ibotenic acid, domoic acid) triggered [Ca2+]i responses in MCC. Antagonists, such as phencyclidine, ketamine and dextromethorphan, were also readily identified. Thus, the MCC developed here may fill an important gap in the panel of test systems available to characterize the effects of chemicals on neurotransmitter receptors.
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Hassoun AER, Ujević I, Mahfouz C, Fakhri M, Roje-Busatto R, Jemaa S, Nazlić N. Occurrence of domoic acid and cyclic imines in marine biota from Lebanon-Eastern Mediterranean Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142542. [PMID: 33035983 DOI: 10.1016/j.scitotenv.2020.142542] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/07/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
Marine biotoxins are naturally existing chemicals produced by toxic algae and can accumulate in marine biota. When consumed with seafood, these phycotoxins can cause human intoxication with symptoms varying from barely-noticed illness to death depending on the type of toxin and its concentration. Recently, the occurrence of marine biotoxins has been given special attention in the Mediterranean as it increased in frequency and severity due to anthropogenic pressures and climate change. Up to our knowledge, no previous study reported the presence of lipophilic toxins (LTs) and cyclic imines (CIs) in marine biota in Lebanon. Hence, this study reports LTs and CIs in marine organisms: one gastropod (Phorcus turbinatus), two bivalves (Spondylus spinosus and Patella rustica complex) and one fish species (Siganus rivulatus), collected from various Lebanese coastal areas. The results show values below the limit of detection (LOD) for okadaic acid, dinophysistoxin-1 and 2, pectenotoxin-1 and 2, yessotoxins, azaspiracids and saxitoxins. The spiny oyster (S. spinosus) showed the highest levels of domoic acid (DA; 3.88 mg kg-1), gymnodimine (GYM-B) and spirolide (SPX) (102.9 and 15.07 μg kg-1, respectively) in congruence with the occurrence of high abundance of Pseudo-nitzchia spp., Gymnodinium spp., and Alexandrium spp. DA levels were below the European Union (EU) regulatory limit, but higher than the Lowest Observed Adverse Effect Level (0.9 μg g-1) for neurotoxicity in humans and lower than the Acute Reference Dose (30 μg kg-1 bw) both set by the European Food Safety Authority (EFSA, 2009). Based on these findings, it is unlikely that a health risk exists due to the exposure to these toxins through seafood consumption in Lebanon. Despite this fact, the chronic toxicity of DA, GYMs and SPXs remains unclear and the effect of the repetitive consumption of contaminated seafood needs to be more investigated.
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Affiliation(s)
- Abed El Rahman Hassoun
- National Council for Scientific Research, National Center for Marine Sciences, P.O. Box, 534, Batroun, Lebanon.
| | - Ivana Ujević
- Laboratory of Plankton and Shellfish Toxicity, Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
| | - Céline Mahfouz
- National Council for Scientific Research, National Center for Marine Sciences, P.O. Box, 534, Batroun, Lebanon
| | - Milad Fakhri
- National Council for Scientific Research, National Center for Marine Sciences, P.O. Box, 534, Batroun, Lebanon
| | - Romana Roje-Busatto
- Laboratory of Plankton and Shellfish Toxicity, Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
| | - Sharif Jemaa
- National Council for Scientific Research, National Center for Marine Sciences, P.O. Box, 534, Batroun, Lebanon
| | - Nikša Nazlić
- Laboratory of Plankton and Shellfish Toxicity, Institute of Oceanography and Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
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Grant KS, Crouthamel B, Kenney C, McKain N, Petroff R, Shum S, Jing J, Isoherranen N, Burbacher TM. Preclinical modeling of exposure to a global marine bio-contaminant: Effects of in utero Domoic acid exposure on neonatal behavior and infant memory. Neurotoxicol Teratol 2019; 73:1-8. [PMID: 30690118 PMCID: PMC6511476 DOI: 10.1016/j.ntt.2019.01.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 01/26/2023]
Abstract
Domoic Acid (DA) is a naturally-occurring marine neurotoxin that is increasingly recognized as an important public health issue. Prenatal DA exposure occurs through the maternal consumption of contaminated shellfish/finfish. To better understand the fetal risks associated with DA, we initiated a longitudinal, preclinical study focused on the reproductive and developmental effects of chronic, low-dose oral DA exposure. To this end, 32 adult female Macaca fascicularis monkeys were orally dosed with 0, 0.075 or 0.15 mg/kg/day DA on a daily basis prior to breeding and throughout breeding and pregnancy. The doses included the proposed human Tolerable Daily Intake (TDI) (0.075 mg/kg/day) for DA. Adult females were bred to nonexposed males. To evaluate development during early infancy, offspring were administered a Neonatal Assessment modeled after the human Neonatal Behavior Assessment Scale and a series of Visual Recognition Memory problems using the novelty paradigm. Results indicated that prenatal DA exposure did not impact early survival reflexes or responsivity to the environment. Findings from the recognition memory assessment, given between 1 and 2 months of age, showed that exposed and control infants demonstrated robust novelty scores when test problems were relatively easy to solve. Performance was not diminished by the introduction of delay periods. However, when more difficult recognition problems were introduced, the looking behavior of the 0.15 mg/kg DA group was random and infants failed to show differential visual attention to novel test stimuli. This finding suggests subtle but significant impairment in recognition memory and demonstrates that chronic fetal exposure to DA may impact developing cognitive processes.
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Affiliation(s)
- Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Washington National Primate Research Center, 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
| | - Caroline Kenney
- Washington National Primate Research Center, 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
| | - 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
| | - Jing Jing
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Nina Isoherranen
- Center on Human Development and Disability, University of Washington, Seattle, WA, USA; Department of Pharmaceutics, University of Washington, 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; Washington National Primate Research Center, Seattle, WA, 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: 2.6] [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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Lefebvre KA, Hendrix A, Halaska B, Duignan P, Shum S, Isoherranen N, Marcinek DJ, Gulland FMD. Domoic acid in California sea lion fetal fluids indicates continuous exposure to a neuroteratogen poses risks to mammals. HARMFUL ALGAE 2018; 79:53-57. [PMID: 30420016 PMCID: PMC7297052 DOI: 10.1016/j.hal.2018.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 05/20/2023]
Abstract
Domoic acid (DA) is a neuroexcitotoxic amino acid that is naturally produced by some species of marine diatoms during harmful algal blooms (HABs). The toxin is transferred through the food web from plantivorous fish and shellfish to marine mammals resulting in significant morbidity and mortality. Due to the timing and location of DA producing HABs, it is well documented that pregnant female California sea lions (CSL) are regularly exposed to DA through their diet thereby posing exposure risks to a neuroteratogen in developing fetuses. In the present study, fluids from 36 fetuses sampled from naturally exposed pregnant CSLs were examined for DA. Domoic acid was detected in 79% of amniotic fluid (n = 24), 67% of allantoic fluid (n = 9), 75% of urine (n = 4), 41% of meconium (n = 17) and 29% of stomach content (n = 21) samples opportunistically collected from CSL fetuses. The distribution of DA in fetal samples indicates an increased prenatal exposure risk due to recirculation of DA in fetal fluids and continuous exposure to the developing brain.
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Affiliation(s)
- 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.
| | - Alicia Hendrix
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States
| | - Barbie Halaska
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, United States
| | - Padraig Duignan
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, United States
| | - Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, United States
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, United States
| | - David J Marcinek
- Department of Radiology, Pathology, and Bioengineering, University of Washington, Seattle, WA 98109, United States
| | - Frances M D Gulland
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, United States
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Vilariño N, Louzao MC, Abal P, Cagide E, Carrera C, Vieytes MR, Botana LM. Human Poisoning from Marine Toxins: Unknowns for Optimal Consumer Protection. Toxins (Basel) 2018; 10:E324. [PMID: 30096904 PMCID: PMC6116008 DOI: 10.3390/toxins10080324] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 01/21/2023] Open
Abstract
Marine biotoxins are produced by aquatic microorganisms and accumulate in shellfish or finfish following the food web. These toxins usually reach human consumers by ingestion of contaminated seafood, although other exposure routes like inhalation or contact have also been reported and may cause serious illness. This review shows the current data regarding the symptoms of acute intoxication for several toxin classes, including paralytic toxins, amnesic toxins, ciguatoxins, brevetoxins, tetrodotoxins, diarrheic toxins, azaspiracids and palytoxins. The information available about chronic toxicity and relative potency of different analogs within a toxin class are also reported. The gaps of toxicological knowledge that should be studied to improve human health protection are discussed. In general, gathering of epidemiological data in humans, chronic toxicity studies and exploring relative potency by oral administration are critical to minimize human health risks related to these toxin classes in the near future.
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Affiliation(s)
- Natalia Vilariño
- Departamento de Farmacología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
| | - M Carmen Louzao
- Departamento de Farmacología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
| | - Paula Abal
- Departamento de Farmacología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
| | - Eva Cagide
- Laboratorio CIFGA S.A., Plaza Santo Domingo 20-5°, 27001 Lugo, Spain.
| | - Cristina Carrera
- Departamento de Farmacología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
- Hospital Veterinario Universitario Rof Codina, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
| | - Mercedes R Vieytes
- Departamento de Fisiología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
| | - Luis M Botana
- Departamento de Farmacología, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
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Progressive changes in hippocampal cytoarchitecture in a neurodevelopmental rat model of epilepsy: implications for understanding presymptomatic epileptogenesis, predictive diagnosis, and targeted treatments. EPMA J 2017; 8:247-254. [PMID: 29021835 DOI: 10.1007/s13167-017-0111-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/10/2017] [Indexed: 12/26/2022]
Abstract
Epilepsies affect about 4% of the population and are frequently characterized by a prolonged "silent" period before the onset of spontaneous seizures. Most current animal models of epilepsy either involve acute seizure induction or kindling protocols that induce repetitive seizures. We have developed a rat model of epilepsy that is characterized by a slowly progressing series of behavioral abnormalities prior to the onset of behavioral seizures. In the current study, we further describe an accompanying progression of cytoarchitectural changes in the hippocampal formation. Groups of male and female SD rats received serial injections of a low dose of domoic acid (0.020 mg/kg) (or vehicle) throughout the second week of life. Postmortem hippocampal tissue was obtained on postnatal days 29, 64, and 90 and processed for glial fibrillary acidic protein (GFAP), NeuN, and calbindin expression. The data revealed no significant changes on postnatal day (PND) 29 but a significant increase in hilar NeuN-positive cells in some regions on PND 64 and 90 that were identified as ectopic granule cells. Further, an increase in GFAP positive cell counts and evidence of reactive astrogliosis was found on PND 90 but not at earlier time points. We conclude that changes in cellular expression, possibly due to on-going non-convulsive seizures, develop slowly in this model and may contribute to progressive brain dysfunction that culminates in a seizure-prone phenotype.
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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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Silbergeld EK. Drinking Water and the Developing Brain. CEREBRUM : THE DANA FORUM ON BRAIN SCIENCE 2016; 2016:cer-09-16. [PMID: 28058090 PMCID: PMC5198753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
While the problem of unsafe tap water in Flint, Michigan fueled outrage and better awareness in regard to the hazards of lead in tap water, the problem has existed in city after city for years in the US and in other countries. Our author, a winner of the MacArthur Foundation "genius" grant for her work in identifying preventable causes of human disease related to environmental exposures, points out that problems extend well beyond lead. Many potentially harmful contaminants have yet to be evaluated, much less regulated. Her article examines a number of neurotoxins and related issues as they pertain to brain development.
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Abstract
Over the past 60 years, a large number of selective neurotoxins were discovered and developed, making it possible to animal-model a broad range of human neuropsychiatric and neurodevelopmental disorders. In this paper, we highlight those neurotoxins that are most commonly used as neuroteratologic agents, to either produce lifelong destruction of neurons of a particular phenotype, or a group of neurons linked by a specific class of transporter proteins (i.e., dopamine transporter) or body of receptors for a specific neurotransmitter (i.e., NMDA class of glutamate receptors). Actions of a range of neurotoxins are described: 6-hydroxydopamine (6-OHDA), 6-hydroxydopa, DSP-4, MPTP, methamphetamine, IgG-saporin, domoate, NMDA receptor antagonists, and valproate. Their neuroteratologic features are outlined, as well as those of nerve growth factor, epidermal growth factor, and that of stress. The value of each of these neurotoxins in animal modeling of human neurologic, neurodegenerative, and neuropsychiatric disorders is discussed in terms of the respective value as well as limitations of the derived animal model. Neuroteratologic agents have proven to be of immense importance for understanding how associated neural systems in human neural disorders may be better targeted by new therapeutic agents.
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Affiliation(s)
- Trevor Archer
- Department of Psychology, University of Gothenburg, Box 500, 430 50, Gothenburg, Sweden.
| | - Richard M Kostrzewa
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, PO Box 70577, Johnson City, TN, 37614, USA
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