Effects of sterigmatocystin on esophageal epithelium and experimental reflux esophagitis in rats

Aspergilli series Versicolores: importance of species identification in the clinical setting

The moulds of the genus Aspergillus section Nidulantes series Versicolores are ubiquitous and particularly recurrent in indoor air. They are considered present in 70% of the bioaerosols to which we are exposed most of our time spent indoors. With the taxonomic revision proposed in 2012 and the discovery of four new species, the series Versicolores currently includes 18 species. These moulds, although considered as cryptic (except Aspergillus sydowii), are opportunistic pathogens that can exhibit increased minimal inhibitory concentrations to conventional antifungal agents. In this review, we discuss the ecology and clinical implications of each species belonging to the series Versicolores. This survey also highlights the lack of consideration for taxonomic revisions in clinical practice and in scientific studies which greatly limits the acquisition of specific knowledge on species belonging to the series Versicolores.

The effect of ochratoxin A on cytotoxicity and glucose metabolism in human esophageal epithelium Het-1A cells

Ochratoxin A (OTA) is a widespread mycotoxin worldwide that causes major health risks. The esophageal epithelium is unavoidably exposed to food contaminated OTA after ingestion. Yet, few studies have involved in the putative effects of OTA on the cytotoxicity and glucose metabolism responses on esophageal epithelial cells. In this in vitro study, we aimed to investigate the effects of OTA on esophageal epithelial cell intracellular apoptosis, oxidative stress, DNA damage, mitochondrial function and glucose metabolism. Human esophageal epithelial Het-1A cells were exposed to 2.5, 5 or 10 μM OTA for 24 h. The results showed that OTA decreased cell viability and concomitantly increased apoptosis-related indices, reactive oxygen species generation, oxidative DNA damage, mitochondrial dysfunction and mitochondrial apoptotic pathway activation. In addition, OTA switched the glucose metabolism of Het-1A cells from oxidative phosphorylation towards glycolysis by decreasing the expression of tricarboxylic acid cycle-associated enzymes such as α-ketoglutarate dehydrogenase and isocitrate dehydrogenase 1 and by increasing pyruvate dehydrogenase kinase 1 expression. The data indicated that cell apoptosis, oxidative damage, mitochondrial dysfunction and glucose metabolism perturbation might play pivotal roles in the mechanism of OTA-induced esophageal toxicity.

Toxicological and Medical Aspects of Aspergillus-Derived Mycotoxins Entering the Feed and Food Chain

Due to Earth's changing climate, the ongoing and foreseeable spreading of mycotoxigenic Aspergillus species has increased the possibility of mycotoxin contamination in the feed and food production chain. These harmful mycotoxins have aroused serious health and economic problems since their first appearance. The most potent Aspergillus-derived mycotoxins include aflatoxins, ochratoxins, gliotoxin, fumonisins, sterigmatocystin, and patulin. Some of them can be found in dairy products, mainly in milk and cheese, as well as in fresh and especially in dried fruits and vegetables, in nut products, typically in groundnuts, in oil seeds, in coffee beans, in different grain products, like rice, wheat, barley, rye, and frequently in maize and, furthermore, even in the liver of livestock fed by mycotoxin-contaminated forage. Though the mycotoxins present in the feed and food chain are well documented, the human physiological effects of mycotoxin exposure are not yet fully understood. It is known that mycotoxins have nephrotoxic, genotoxic, teratogenic, carcinogenic, and cytotoxic properties and, as a consequence, these toxins may cause liver carcinomas, renal dysfunctions, and also immunosuppressed states. The deleterious physiological effects of mycotoxins on humans are still a first-priority question. In food production and also in the case of acute and chronic poisoning, there are possibilities to set suitable food safety measures into operation to minimize the effects of mycotoxin contaminations. On the other hand, preventive actions are always better, due to the multivariate nature of mycotoxin exposures. In this review, the occurrence and toxicological features of major Aspergillus-derived mycotoxins are summarized and, furthermore, the possibilities of treatments in the medical practice to heal the deleterious consequences of acute and/or chronic exposures are presented.