Neurotoxic Cyanobacterial Toxins

Abstract

Cyanobacteria (commonly referred to as blue green algae) can produce over 100 known toxins (cyanotoxins). In this chapter, cyanotoxins with established and emerging neurotoxic properties are reviewed. A variety of neurotoxic mechanisms and effects have been revealed by animal and cell culture studies including protein misfolding, neuroinflammation, blood-brain barrier damage, oxidative stress as well as altered neurotransmission, and calcium and protein homeostasis. Although several cyanotoxins exhibit acute neurotoxicity, their chronic effects remain unclear. At least one cyanobacterial neurotoxin, β-Nmethylamino-L-alanine, has been linked to amyotrophic lateral sclerosis and Alzheimer’s disease, however causal links between cyanotoxins and neurodegeneration are overall currently tenuous. In light of the diversity of proposed neurotoxic mechanisms, it is important to consider their potential effect(s) of cyanotoxins on their peripheral and central nervous system, especially if low level exposures are experienced over the course of months or years. Neurotoxin exposure routes as well as synergism between cyanotoxins and/or additional environmental components may also contribute to their overall toxicity and are considered here.While there are presently several potential treatments for cyanotoxin exposure, most are symptomatic. Together, a greater investment in environmental toxin monitoring as well as understanding of the biological mechanisms of cyanotoxins will be valuable in reducing any negative impacts on human health.