Defining the neurotoxin derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: A case/control study

HLA gene variations and mycotoxin toxicity: Four case reports

Mycotoxins are produced by certain molds that can cause many health effects. We present four human cases of prolonged consistent mycotoxins exposure linked to genetic variations in human leukocyte antigen (HLA) alleles. The HLA-DR/DQ isotype alleles are linked to mycotoxins susceptibility due to the lack of proper immune response; individuals with these alleles are poor eliminators of mycotoxins from their system. Four subjects with variations in their HLA-DR alleles were exposed to mycotoxins from living in mold-infested houses and experienced persistent mold-related symptoms long after moving out from the mold-infested houses and only exposed to the levels of molds found in the ambient air. From one of the subjects, two urine samples were collected ~ 18 months apart after the cessation of exposure. Urinary elimination rate was extremely slow for two of the mycotoxins (ochratoxin A [OTA] and mycophenolic acid [MPA]) detected in both samples. In 18 months, decline in OTA level was only ~ 3-fold (estimated t½ of ~ 311 days) and decline in MPA level was ~ 11-fold (estimated t½ of ~ 160 days), which was ~ 10- and ~ 213-fold slower than expected in individuals without HLA-DR alleles, respectively. We estimated that ~ 4.3 and ~ 2.2 years will be required for OTA and MPA to reach < LLQ in urine, respectively. Three other subjects with variations in HLA-DR alleles were members of a family who lived in a mold-infested house for 4 years. They kept experiencing mold-related issues >2 years after moving to a non-mold-infested house. Consistent exposure was confirmed by the presence of several mycotoxins in urine >2 years after the secession of higher than background (from outdoor ambient air) exposure. This was consistent with the extremely slow elimination of mycotoxins from their system. Variations in HLA-DR alleles can, consequently, make even short periods of exposure to chronic exposure scenarios with related adverse health effects. It is, therefore, important to determine genetic predisposition as a reason for prolonged/lingering mold-related symptoms long after the cessation of higher than background exposure. Increased human exposure to mycotoxins is expected from increased mold infestation that is anticipated due to rising CO2, temperature, and humidity from the climate change with possibly increased adverse health effects, especially in individuals with genetic susceptibility to mold toxicity.

Chronic Ciguatera Poisoning: A Case Report

Ciguatera is a common marine, toxin-borne illness caused by the consumption of fish that contain toxins that activate voltage-sensitive sodium channels. The clinical manifestations of ciguatera are typically self-limited, but chronic symptoms may occur in a minority of patients. This report describes a case of ciguatera poisoning with chronic symptoms, including pruritus and paresthesias. A 40-y-old man was diagnosed with ciguatera poisoning after consuming amberjack while vacationing in the US Virgin Islands. His initial symptoms, including diarrhea, cold allodynia, and extremity paresthesias, evolved into chronic, fluctuating paresthesias and pruritus that became worse after the consumption of alcohol, fish, nuts, and chocolate. After a comprehensive neurologic evaluation failed to reveal another cause for his symptoms, he was diagnosed with chronic ciguatera poisoning. His neuropathic symptoms were treated with duloxetine and pregabalin, and he was counseled to avoid foods that triggered his symptoms. Chronic ciguatera is a clinical diagnosis. Signs and symptoms of chronic ciguatera can include fatigue, myalgias, headache, and pruritus. The pathophysiology of chronic ciguatera is incompletely understood but may involve genetic factors or immune dysregulation. Treatment involves supportive care and avoidance of foods and environmental conditions that may exacerbate symptoms.

Screening for Predictors of Chronic Ciguatera Poisoning: An Exploratory Analysis among Hospitalized Cases from French Polynesia

Ciguatera poisoning is a globally occurring seafood disease caused by the ingestion of marine products contaminated with dinoflagellate produced neurotoxins. Persistent forms of ciguatera, which prove to be highly debilitating, are poorly studied and represent a significant medical issue. The present study aims to better understand chronic ciguatera manifestations and identify potential predictive factors for their duration. Medical files of 49 patients were analyzed, and the post-hospitalization evolution of the disease assessed through a follow-up questionnaire. A rigorous logistic lasso regression model was applied to select significant predictors from a list of 37 patient characteristics potentially predictive of having chronic symptoms. Missing data were handled by complete case analysis, and a survival analysis was implemented. All models used standardized variables, and multiple comparisons in the survival analyses were handled by Bonferroni correction. Among all studied variables, five significant predictors of having symptoms lasting ≥3 months were identified: age, tobacco consumption, acute bradycardia, laboratory measures of urea, and neutrophils. This exploratory, hypothesis-generating study contributes to the development of ciguatera epidemiology by narrowing the list from 37 possible predictors to a list of five predictors that seem worth further investigation as candidate risk factors in more targeted studies of ciguatera symptom duration.

Neurological Disturbances of Ciguatera Poisoning: Clinical Features and Pathophysiological Basis

Ciguatera fish poisoning (CFP), the most prevalent seafood poisoning worldwide, is caused by the consumption of tropical and subtropical fish contaminated with potent neurotoxins called ciguatoxins (CTXs). Ciguatera is a complex clinical syndrome in which peripheral neurological signs predominate in the acute phase of the intoxication but also persist or reoccur long afterward. Their recognition is of particular importance in establishing the diagnosis, which is clinically-based and can be a challenge for physicians unfamiliar with CFP. To date, no specific treatment exists. Physiopathologically, the primary targets of CTXs are well identified, as are the secondary events that may contribute to CFP symptomatology. This review describes the clinical features, focusing on the sensory disturbances, and then reports on the neuronal targets and effects of CTXs, as well as the neurophysiological and histological studies that have contributed to existing knowledge of CFP neuropathophysiology at the molecular, neurocellular and nerve levels.

Tectus niloticus (Tegulidae, Gastropod) as a Novel Vector of Ciguatera Poisoning: Clinical Characterization and Follow-Up of a Mass Poisoning Event in Nuku Hiva Island (French Polynesia)

Ciguatera fish poisoning (CFP) is the most prevalent non-bacterial food-borne form of poisoning in French Polynesia, which results from the consumption of coral reef fish naturally contaminated with ciguatoxins produced by dinoflagellates in the genus Gambierdiscus. Since the early 2000s, this French territory has also witnessed the emergence of atypical forms of ciguatera, known as ciguatera shellfish poisoning (CSP), associated with the consumption of marine invertebrates. In June 2014, nine tourists simultaneously developed a major and persistent poisoning syndrome following the consumption of the gastropod Tectus niloticus collected in Anaho, a secluded bay of Nuku Hiva Island (Marquesas Archipelago, French Polynesia). The unusual nature and severity of this event prompted a multidisciplinary investigation in order to characterize the etiology and document the short/long-term health consequences of this mass-poisoning event. This paper presents the results of clinical investigations based on hospital medical records, medical follow-up conducted six and 20 months post-poisoning, including a case description. This study is the first to describe the medical signature of T. niloticus poisoning in French Polynesia and contributed to alerting local authorities about the potential health hazards associated with the consumption of this gastropod, which is highly prized by local communities in Pacific island countries and territories.

Immune effects of the neurotoxins ciguatoxins and brevetoxins

Ciguatoxins (CTXs) and brevetoxins (PbTxs) are phycotoxins that can accumulate along the marine food chain and thus cause seafood poisoning in humans, namely "ciguatera fish poisoning" (CFP) and "neurotoxic shellfish poisoning" (NSP), respectively. CFP is characterized by early gastrointestinal symptoms and typical sensory disorders (paraesthesia, pain, pruritus and cold dysaesthesia), which can persist several weeks and, in some cases, several months or years. NSP is considered a mild form of CFP with similar but less severe symptoms. After inhaled exposure, PbTxs can also cause respiratory tract irritation in healthy subjects and asthma exacerbations in predisposed subjects, whose respiratory functions may be disrupted for several days following PbTx inhalation. Mechanistically, it is well established that CTX- or PbTx-induced disturbances are primarily mainly due to voltage-gated sodium channel activation in sensory and motor peripheral nervous system. However, little is known about the pathophysiology or a potential individual susceptibility to long lasting effects of CFP/NSP. In addition to their action on the nervous system, PbTxs and CTXs were also shown to exert effects on the immune system. However, their role in the pathophysiology of syndromes induced by CTX or PbTx exposure is poorly documented. The aim of this review is to inventory the literature thus far on the inflammatory and immune effects of PbTxs and CTXs.

Ciguatoxins Evoke Potent CGRP Release by Activation of Voltage-Gated Sodium Channel Subtypes NaV1.9, NaV1.7 and NaV1.1

Ciguatoxins (CTXs) are marine toxins that cause ciguatera fish poisoning, a debilitating disease dominated by sensory and neurological disturbances that include cold allodynia and various painful symptoms as well as long-lasting pruritus. Although CTXs are known as the most potent mammalian sodium channel activator toxins, the etiology of many of its neurosensory symptoms remains unresolved. We recently described that local application of 1 nM Pacific Ciguatoxin-1 (P-CTX-1) into the skin of human subjects induces a long-lasting, painful axon reflex flare and that CTXs are particularly effective in releasing calcitonin-gene related peptide (CGRP) from nerve terminals. In this study, we used mouse and rat skin preparations and enzyme-linked immunosorbent assays (ELISA) to study the molecular mechanism by which P-CTX-1 induces CGRP release. We show that P-CTX-1 induces CGRP release more effectively in mouse as compared to rat skin, exhibiting EC₅₀ concentrations in the low nanomolar range. P-CTX-1-induced CGRP release from skin is dependent on extracellular calcium and sodium, but independent from the activation of various thermosensory transient receptor potential (TRP) ion channels. In contrast, lidocaine and tetrodotoxin (TTX) reduce CGRP release by 53–75%, with the remaining fraction involving L-type and T-type voltage-gated calcium channels (VGCC). Using transgenic mice, we revealed that the TTX-resistant voltage-gated sodium channel (VGSC) Na_V1.9, but not Na_V1.8 or Na_V1.7 alone and the combined activation of the TTX-sensitive VGSC subtypes Na_V1.7 and Na_V1.1 carry the largest part of the P-CTX-1-caused CGRP release of 42% and 34%, respectively. Given the contribution of CGRP to nociceptive and itch sensing pathways, our findings contribute to a better understanding of sensory symptoms of acute and chronic ciguatera that may help in the identification of potential therapeutics.

Rheumatoid arthritis following ciguatera poisoning: A case report

Objective: To report the first case of ciguatera-associated rheumatoid arthritis in Japan.

Patient: A 53-year-old man presented to our clinic with morning stiffness and pain in the fingers and wrists.

Results: For six months, he had suffered from chronic pain in both hands and shoulders caused by ciguatera poisoning. He was referred to a local general hospital and diagnosed with RA.

Conclusion: When synovitis becomes evident in chronic ciguatera poisoning, reevaluation is necessary, including investigation of chronic arthritis, which might be associated with the onset of RA.

An Updated Review of Ciguatera Fish Poisoning: Clinical, Epidemiological, Environmental, and Public Health Management

Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world. It causes substantial human health, social, and economic impacts. The illness produces a complex array of gastrointestinal, neurological and neuropsychological, and cardiovascular symptoms, which may last days, weeks, or months. This paper is a general review of CFP including the human health effects of exposure to ciguatoxins (CTXs), diagnosis, human pathophysiology of CFP, treatment, detection of CTXs in fish, epidemiology of the illness, global dimensions, prevention, future directions, and recommendations for clinicians and patients. It updates and expands upon the previous review of CFP published by Friedman et al. (2008) and addresses new insights and relevant emerging global themes such as climate and environmental change, international market issues, and socioeconomic impacts of CFP. It also provides a proposed universal case definition for CFP designed to account for the variability in symptom presentation across different geographic regions. Information that is important but unchanged since the previous review has been reiterated. This article is intended for a broad audience, including resource and fishery managers, commercial and recreational fishers, public health officials, medical professionals, and other interested parties.

Reversal of Refractory Ulcerative Colitis and Severe Chronic Fatigue Syndrome Symptoms Arising from Immune Disturbance in an HLA-DR/DQ Genetically Susceptible Individual with Multiple Biotoxin Exposures

Patient: Male, 25

Final Diagnosis: Ulcerative colitis and chronic fatigue syndrome

Symptoms: Colitis • profound fatigue • multi-joint pain • cognitive impairment • corneal keratitis

Medication: —

Clinical Procedure: VIP replacement therapy

Specialty: Family Medicine

Transcriptomic signatures in whole blood of patients who acquire a chronic inflammatory response syndrome (CIRS) following an exposure to the marine toxin ciguatoxin

Background

Ciguatoxins (CTXs) are polyether marine neurotoxins found in multiple reef-fish species and are potent activators of voltage-gated sodium channels. It is estimated that up to 500,000 people annually experience acute ciguatera poisoning from consuming toxic fish and a small percentage of these victims will develop a chronic, multisymptom, multisystem illness, which can last years, termed a Chronic Inflammatory Response Syndrome (CIRS). Symptoms of ciguatera CIRS include fatigue, cognitive deficits, neurologic deficits, pain and sensitivity to light. There are few treatment options for ciguatera CIRS since little is known about its pathophysiology.

Methods

This study characterizes the transcriptional profile in whole blood of 11 patients with ciguatera-induced CIRS and 11 normal controls run in duplicate using Agilent one color whole genome microarrays. Differential expression was determined by using a combination of moderated t-test p-value and fold change (FC). Significant genes were subjected to gene ontology, principal component analysis and SVM classification. Seven significant genes found by microarray were validated by PCR.

Results

Using a low stringency (p < 0.05 and FC > 1.4) and a high stringency (p < 0.01 and FC > 1.5) filter, the resulting gene sets of 185 and 55, respectively, showed clear separation of cases and controls by PCA as well as 100% classification accuracy by SVM, indicating that the gene profiles can separate patients from controls. PCR results of 7 genes showed a 95% correlation to microarray data. Several genes identified by microarray are important in wound healing (CD9, CD36, vWF and Factor XIII), adaptive immunity (HLA-DQB1, DQB2, IL18R1 and IL5RA) and innate immunity (GZMK, TOLLIP, SIGIRR and VIPR2), overlapping several areas shown to be disrupted in a mouse model of acute exposure to ciguatoxin. Another area of interest was differential expression of long, non-coding sequences, or lncRNA.

Conclusions

Disruptions of innate and adaptive immune mechanisms were recorded at both the genomic and proteomic level. A disruption in the HLA-T cell receptor axis could indicate HLA haplotype sensitivity for this chronic syndrome, as noted in many autoimmune conditions. Taken together, these indicators of illness provide additional insights into pathophysiology and potential therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-015-0089-x) contains supplementary material, which is available to authorized users.

Neuroprotective effects of rosmarinic acid on ciguatoxin in primary human neurons

Ciguatoxin (CTX), is a toxic compound produced by microalgae (dinoflagellate) Gambierdiscus spp., and is bio-accumulated and bio-transformed through the marine food chain causing neurological deficits. To determine the mechanism of CTX-mediated cytotoxicity in human neurons, we measured extracellular lactate dehydrogenase (LDH) activity, intracellular levels of nicotinamide adenine dinucleotide (NAD(+)) and H2AX phosphorylation at serine 139 as a measure for DNA damage in primary cultures of human neurons treated with Pacific (P)-CTX-1B and P-CTX-3C. We found these marine toxins can induce a time and dose-dependent increase in extracellular LDH activity, with a concomitant decline in intracellular NAD(+) levels and increased DNA damage at the concentration range of 5-200 nM. We also showed that pre- and post-treatment with rosmarinic acid (RA), the active constituent of the Heliotropium foertherianum (Boraginaceae) can attenuate CTX-mediated neurotoxicity. These results further highlight the potential of RA in the treatment of CTX-induced neurological deficits.

A review of traditional remedies of ciguatera fish poisoning in the Pacific

Ciguatera fish poisoning (CFP) is an illness caused by eating tropical coral fish contaminated with ciguatoxins (CTXs). The clinical management of patients with CFP is generally supportive and symptomatic in nature as no antidote exists. Of the many drugs prescribed, several have been claimed to be efficient in small, uncontrolled studies, but the outcomes of treatments with these medicines are often contradictory. In New Caledonia, traditional remedies are commonly employed in the treatment of CFP and of the 90 plant species catalogued as useful in CFP, the most popular herbal remedy by far is a decoction prepared from the leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae). Other important plants used in the treatment of CFP include Euphorbia hirta L. (Euphorbiaceae) and Vitex L. sp. (Lamiaceae). This review focuses on the evidence for efficacy of these species and pharmacological studies which support their use. Other plants used in CFP and the conventional treatment of CFP are also discussed briefly.

Gene expression profiling in brain of mice exposed to the marine neurotoxin ciguatoxin reveals an acute anti-inflammatory, neuroprotective response

BACKGROUND

Ciguatoxins (CTXs) are polyether marine neurotoxins and potent activators of voltage-gated sodium channels. This toxin is carried by multiple reef-fish species and human consumption of ciguatoxins can result in an explosive gastrointestinal/neurologic illness. This study characterizes the global transcriptional response in mouse brain to a symptomatic dose of the highly toxic Pacific ciguatoxin P-CTX-1 and additionally compares this data to transcriptional profiles from liver and whole blood examined previously. Adult male C57/BL6 mice were injected with 0.26 ng/g P-CTX-1 while controls received only vehicle. Animals were sacrificed at 1, 4 and 24 hrs and transcriptional profiling was performed on brain RNA with Agilent whole genome microarrays. RT-PCR was used to independently validate gene expression and the web tool DAVID was used to analyze gene ontology (GO) and molecular pathway enrichment of the gene expression data.

RESULTS

A pronounced 4°C hypothermic response was recorded in these mice, reaching a minimum at 1 hr and lasting for 8 hrs post toxin exposure. Ratio expression data were filtered by intensity, fold change and p-value, with the resulting data used for time course analysis, K-means clustering, ontology classification and KEGG pathway enrichment. Top GO hits for this gene set included acute phase response and mono-oxygenase activity. Molecular pathway analysis showed enrichment for complement/coagulation cascades and metabolism of xenobiotics. Many immediate early genes such as Fos, Jun and Early Growth Response isoforms were down-regulated although others associated with stress such as glucocorticoid responsive genes were up-regulated. Real time PCR confirmation was performed on 22 differentially expressed genes with a correlation of 0.9 (Spearman's Rho, p < 0.0001) with microarray results.

CONCLUSIONS

Many of the genes differentially expressed in this study, in parallel with the hypothermia, figure prominently in protection against neuroinflammation. Pathologic activity of the complement/coagulation cascade has been shown in patients suffering from a chronic form of ciguatera poisoning and is of particular interest in this model. Anti-inflammatory processes were at work not only in the brain but were also seen in whole blood and liver of these animals, creating a systemic anti-inflammatory environment to protect against the initial cellular damage caused by the toxin.