A review and assessment of cyanobacterial toxins as cardiovascular health hazards

Abstract

Eutrophicated waters frequently support bloom-forming cyanobacteria, many of which produce potent cyanobacterial toxins (cyanotoxins). Cyanotoxins can cause adverse health effects in a wide range of organisms where the toxins may target the liver, other internal organs, mucous surfaces and the skin and nervous system. This review surveyed more than 100 studies concerning the cardiovascular toxicity of cyanotoxins and related topics. Over 60 studies have described various negative effects on the cardiovascular system by seven major types of cyanotoxins, i.e. the microcystin (MC), nodularin (NOD), cylindrospermopsin (CYN), anatoxin (ATX), guanitoxin (GNTX), saxitoxin (STX) and lyngbyatoxin (LTX) groups. Much of the research was done on rodents and fish using high, acutely toxin concentrations and unnatural exposure routes (such as intraperitoneal injection), and it is thus concluded that the emphasis in future studies should be on oral, chronic exposure of mammalian species at environmentally relevant concentrations. It is also suggested that future in vivo studies are conducted in parallel with studies on cells and tissues. In the light of the presented evidence, it is likely that cyanotoxins do not constitute a major risk to cardiovascular health under ordinary conditions met in everyday life. The risk of illnesses in other organs, in particular the liver, is higher under the same exposure conditions. However, adverse cardiovascular effects can be expected due to indirect effects arising from damage in other organs. In addition to risks related to extraordinary concentrations of the cyanotoxins and atypical exposure routes, chronic exposure together with co-existing diseases could make some of the cyanotoxins more dangerous to cardiovascular health.

Microcystis sp. AE03 strain in Dal Lake harbors cylindrospermopsin and microcystin synthetase gene cluster

“…The isolated strains from Dal Lake have cyanotoxin biosynthetic gene clusters that have been linked to geographical distribution and toxicity worldwide (Diez-Quijada et al, 2022;Svirčev et al, 2022;Zhang et al, 2022). Microcystis spp.…”

A comprehensive review of the therapeutic potential of cyanobacterial marine bioactives: Unveiling the hidden treasures of the sea

“…under normal conditions cyanotoxins are unlikely to pose a major risk to cardiovascular health, however, they can cause harm due to indirect effects from organ damage. Chronic exposure and coexisting diseases could increase the risk for cardiovascular health (Svirčev et al, 2022). Marine cyanobacteria fix nitrogen and carbon dioxide in organic material, playing a vital role in nutrient cycle.…”

“…These microorganisms are known to produce a variety of bioactive compounds, including toxins, pigments, and antimicrobial agents. In particular, cyanobacterial toxins are implicated in the generation of harmful algal blooms, which can have detrimental effects on marine ecosystems and human health (Svirčev et al, 2022).…”

Sphingobium cyanobacteriorum sp. nov., isolated from fresh water

“…Cyanobacteria serve as the foundation of the food web in aquatic ecosystems through photosynthesis and nitrogen fixation [12]. They produce cyanotoxins, which cause digestive, liver and neurological diseases in humans and mammals [13]. The excessive growth of cyanobacteria, termed cyanobacterial blooms, negatively affects drinking water quality and disrupts ecosystems [14].…”