Abstract

Both paralytic shellfish toxins (PST) and diarrhetic shellfish toxins (DST) correspond to groups of toxins produced by some species of marine dinoflagellates and cyanobacteria, which can be accumulated by different marine species. Shellfish can accumulate great amounts of toxins in their digestive glands. However, when highly contaminated shellfish are eaten by persons, they can produce severe intoxications causing severe problems to public health. Poisonings associated to consumption of seafood (Aulacomya ater) contaminated with PST (8,066 ± 61.37 μg STX equiv 100 g-1 of tissue) have been reported in the south of Chile. Proper and prompt medical attention has allowed obtaining data related to poisoning, such as changes in the respiratory rate, arterial blood pressure, heart rate and levels of toxins in body fluids. Based thereon, appropriate treatments were established in order to revert clinical conditions (hydration with saline solution supplemented with Dobutamine, Furosemide and Ranitidine) after 12 hours of the toxic ingestion. Additionally, extreme factors of poisonings caused by consumption of shellfish with PST (8,575 μg of STX equiv to 100 g-1 of tissue) have caused the death of people between 3 and 4 hours post-consumption. Forensic clinical examinations have allowed ruling out the presence of pathological abnormalities in organs other than the lungs, which stand out for showing pulmonary congestion and edema. Analytical assessment in the different body organs and body fluids (urine, bile and cerebrospinal fluid) allows identification of the levels of distribution and biotransformation of the different toxins that compose PST, highlighting the presence of Saxitoxin (STX) and Gonyautoxins (GTXs) in the gastric content, while neosaxitoxin (neoSTX) and GTXs in urine and bile stand out. Furthermore, poisonings associated with DST in the south of Chile have been related to the consumption of contaminated shellfish with 7-O-acyl-dinophysistoxin-1 (DTX-3) (316.1 ± 17.5 μg OA equiv Kg-1 of digestive glands). DTX-3 has chemical structural properties different to its toxic congeners -Okadaic Acid (OA) and Dinophysistoxin-1 (DTX-1)- which does not inhibit the protein phosphatase 2A and does not cause symptoms for poisonings from DST within the times described (30-120 minutes). The antecedents identified in these poisonings provide evidence of metabolic transformations that cause diarrheal symptoms in times between 15 and 24 hours post-consumption of shellfish, these times being more related to poisonings produced by Vibrio parahaemolyticus or enteropathogenic bacteria. Nevertheless, bacterial analyses in feces of intoxicated patients and assessment of shellfish by mouse bioassay (health standard for DSP-toxins) tend to be negative. Therefore, only the comprehensive analytical assessment in the samples (HPLC - FLD and HPLC - MS/MS) has allowed the identification of the presence of DTX-3 in shellfish, while DTX-1 was identified in feces. A plausible explanation for these results corresponds to the metabolic transformation of DTX-3 into DTX-1 in the stomach of patients intoxicated by the action of digestive enzymes, allowing the breakdown of the 7-O-acyl ester bond, thus favoring chemical retro-conversion to DTX-1. This article shows the clinical and toxicological parameters determined in poisonings associated with PST and DST, showing that these toxins are metabolically modified at rates of varying times according to their chemical nature, allowing them to be eliminated from the body via urine and/or feces excretion, as any xenobiotic. Its potential carcinogenic effect is also revised.