Prevalence of Aspergillus-Derived Mycotoxins (Ochratoxin, Aflatoxin, and Gliotoxin) and Their Distribution in the Urinalysis of ME/CFS Patients

Daphnia magna model for the study of mycotoxins present in food: Gliotoxin, ochratoxin A and its combination

Mycotoxins are low molecular weight compounds present in food and feed. Although their effects on human health have been widely described, their mechanisms of action are still undefined. Gliotoxin (GTX) and ochratoxin A (OTA) are among the most dangerous mycotoxins produced by Aspergillus spp. Therefore, their toxicity was studied in the Daphnia magna model, which has high capacity to predict cytotoxicity and assess ecotoxicity, comparable to mammalian models. The study consisted of a series of tests to evaluate the effects of mycotoxins GTX, OTA and their combinations at different dilutions on Daphnia magna that were conducted according to standardized OECD 202 and 211 guidelines. The following assays were carried out: acute toxicity test, heartbeat, delayed toxicity test, reproduction, growth rate test. Reproducibility was determined by observing the offspring after 21 days of GTX exposure. In acute and delayed toxicity transcript levels of genes involved in xenobiotic metabolism (mox, gst, abcb1, and abcc5), and oxidative stress (vtg-SOD) were analyzed by qPCR. GTX showed acute toxicity and decreased heart rate in D. magna compared to OTA. On the other hand, OTA showed a delayed effect as evidenced by the immobility test. Both mycotoxins showed to increase genes involved in xenobiotic metabolism, while only the mycotoxin mixture increased oxidative stress. These results suggest that the mycotoxins tested could have negative impact on the environment and human health.

Mast cells in the autonomic nervous system and potential role in disorders with dysautonomia and neuroinflammation

Mast cells (MC) are ubiquitous in the body, and they are critical for not only in allergic diseases but also in immunity and inflammation, including having potential involvement in the pathophysiology of dysautonomias and neuroinflammatory disorders. MC are located perivascularly close to nerve endings and sites such as the carotid bodies, heart, hypothalamus, the pineal gland, and the adrenal gland that would allow them not only to regulate but also to be affected by the autonomic nervous system (ANS). MC are stimulated not only by allergens but also many other triggers including some from the ANS that can affect MC release of neurosensitizing, proinflammatory, and vasoactive mediators. Hence, MC may be able to regulate homeostatic functions that seem to be dysfunctional in many conditions, such as postural orthostatic tachycardia syndrome, autism spectrum disorder, myalgic encephalomyelitis/chronic fatigue syndrome, and Long-COVID syndrome. The evidence indicates that there is a possible association between these conditions and diseases associated with MC activation. There is no effective treatment for any form of these conditions other than minimizing symptoms. Given the many ways MC could be activated and the numerous mediators released, it would be important to develop ways to inhibit stimulation of MC and the release of ANS-relevant mediators.

Involvement of pro-inflammatory mediators and cell cycle disruption in neuronal cells induced by gliotoxin and ochratoxin A after individual and combined exposure

Mycotoxins such as gliotoxin (GTX) and ochratoxin A (OTA) are secondary metabolites of Aspergillus and Penicillum found in food and feed. Both mycotoxins have shown to exert a detrimental effect on neuronal activity. The following study was carried out to elucidate the mechanisms by which GTX and OTA exert their toxicity. Non-differentiated SH-SY5Y neuronal-like cells were treated with GTX, OTA and their combinations to assess their cytotoxic effect using the MTT assay during 24, 48 and 72 h of exposure. Based on the results of the cytotoxic assays, cell cycle proliferation and immunological mediators were measured by determining the production of IL-6 and TNF-α using flow cytometry and ELISA, respectively. The IC50 values obtained were 1.24 and 1.35 µM when SH-SY5Y cells were treated with GTX at 48 h and 72 h, respectively. IC50 values of 8.25, 5.49 and 4.5 µM were obtained for OTA treatment at 24 h, 48 h and 72 h, respectively. The SubG0 phase increased in both treatments at 24 and 48 h. On the other hand, IL-6 and TNF-α production was increased in all mycotoxin treatments studied and was more pronounced for [GTX + OTA] after 48 h exposure. The additive and synergistic effect observed by the isobologram analysis between GTX and OTA resulted to a higher cytotoxicity which can be explained by the increased production of IL-6 and TNF-α inflammatory mediators that play an important role in the toxicity mechanism of these mycotoxins.

Ochratoxin A stimulates release of IL-1β, IL-18 and CXCL8 from cultured human microglia

Exposure to mycotoxins has been associated with the development of neuropsychiatric symptoms and Ochratoxin A (OTA) has emerged as one of the main mycotoxins associated with neurotoxicity. However, the mechanism via OTA exerts its neurotoxic effects is not well understood, especially the importance of activated microglia and their contribution to neuroinflammation. Here we report the effect of OTA on cultured immortalized human microglia-SV40, as compared to the effect of neurotensin (NT) and lipopolysaccharide (LPS) used as "positive" triggers. OTA (1, 10 and 100 nM for 24 hrs) stimulated microglia to release in the supernatant fluids statistically significant amounts of IL-1β, IL-18 and CXCL8 assayed with ELISA. Preventing or inhibiting OTA-stimulated activation of microglia by luteolin could be an important way to limit mycotoxin-induced neuroinflammation and improve associated neuropsychiatric diseases.