Arsenic Neurotoxicity in Humans

• Published in: International journal of molecular sciences 2019-07, Vol.20 (14), p.3418
• Main Author: Mochizuki, Hitoshi
• Format: Article
• Language: English
• Subjects: Age Factors; Animals; Apoptosis; Aquifers; Arsenic; Arsenic - metabolism; Arsenic - toxicity; Arsenic Poisoning - metabolism; Biological effects; Cytoskeleton; Degeneration; Deoxyribonucleic acid; Destabilization; Disruption; DNA; DNA biosynthesis; DNA methylation; DNA repair; Dose-Response Relationship, Drug; Drinking water; Environmental Pollutants - toxicity; Environmental Pollution; Enzymes; Experiments; Heavy metals; Humans; JNK3 protein; Kinases; Lipid peroxidation; Lipids; MAP kinase; mechanism; Metabolic Networks and Pathways; Metabolic pathways; Metabolism; metabolite pathway; Metabolites; Mutation; Neurodegeneration; Neurofilaments; Neurotoxicity; Neurotoxicity Syndromes - diagnosis; Neurotoxicity Syndromes - etiology; Neurotoxicity Syndromes - metabolism; Organ Specificity; Oxidation; Oxidative Stress; Peripheral nerves; Protein kinase; Proteins; Researchers; Review; Shellfish; Toroku; Toxicity; Urine; Vitamin B; Vitamin deficiency
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms20143418

Arsenic (As) contamination affects hundreds of millions of people globally. Although the number of patients with chronic As exposure is large, the symptoms and long-term clinical courses of the patients remain unclear. In addition to reviewing the literature on As contamination and toxicity, we provide useful clinical information on medical care for As-exposed patients. Further, As metabolite pathways, toxicity, speculated toxicity mechanisms, and clinical neurological symptoms are documented. Several mechanisms that seem to play key roles in As-induced neurotoxicity, including oxidative stress, apoptosis, thiamine deficiency, and decreased acetyl cholinesterase activity, are described. The observed neurotoxicity predominantly affects peripheral nerves in sensory fibers, with a lesser effect on motor fibers. A sural nerve biopsy showed the axonal degeneration of peripheral nerves mainly in small myelinated and unmyelinated fibers. Exposure to high concentrations of As causes severe central nervous system impairment in infants, but no or minimal impairment in adults. The exposure dose-response relationship was observed in various organs including neurological systems. The symptoms caused by heavy metal pollution (including As) are often nonspecific. Therefore, in order to recognize patients experiencing health problems caused by As, a multifaceted approach is needed, including not only clinicians, but also specialists from multiple fields.