Correlation between alimentary mycotoxin contamination and specific diseases

Mycotoxin contamination in the Arab world: Highlighting the main knowledge gaps and the current legislation

Since the discovery of aflatoxins in the 1960s, knowledge in the mycotoxin research field has increased dramatically. Hundreds of review articles have been published summarizing many different aspects, including mycotoxin contamination per country or region. However, mycotoxin contamination in the Arab world, which includes 22 countries in Africa and Asia, has not yet been specifically reviewed. To this end, the contamination of mycotoxins in the Arab world was reviewed not only to profile the pervasiveness of the problem in this region but also to identify the main knowledge gaps imperiling the safety of food and feed in the future. To the best of our knowledge, 306 (non-)indexed publications in English, Arabic, or French were published from 1977 to 2021, focusing on the natural occurrence of mycotoxins in matrices of 14 different categories. Characteristic factors (e.g., detected mycotoxins, concentrations, and detection methods) were extracted, processed, and visualized. The main results are summarized as follows: (i) research on mycotoxin contamination has increased over the years. However, the accumulated data on their occurrences are scarce to non-existent in some countries; (ii) the state-of-the-art technologies on mycotoxin detection are not broadly implemented neither are contemporary multi-mycotoxin detection strategies, thus showing a need for capacity-building initiatives; and (iii) mycotoxin profiles differ among food and feed categories, as well as between human biofluids. Furthermore, the present work highlights contemporary legislation in the Arab countries and provides future perspectives to mitigate mycotoxins, enhance food and feed safety, and protect the consumer public. Concluding, research initiatives to boost mycotoxin research among Arab countries are strongly recommended.

Self-Sterilizing Laser-Induced Graphene Bacterial Air Filter

Nosocomial infections transmitted through airborne, droplet, aerosol, and particulate-transported modes pose substantial infection risks to patients and healthcare employees. In this study, we demonstrate a self-cleaning filter comprised of laser-induced graphene (LIG), a porous conductive graphene foam formed through photothermal conversion of a polyimide film by a commercial CO₂ laser cutter. LIG was shown to capture particulates and bacteria. The bacteria cannot proliferate even when submerged in culture medium. Through a periodic Joule-heating mechanism, the filter readily reaches >300 °C. This destroys any microorganisms including bacteria, along with molecules that can cause adverse biological reactions and diseases. These molecules include pyrogens, allergens, exotoxins, endotoxins, mycotoxins, nucleic acids, and prions. Capitalizing on the high surface area and thermal stability of LIG, the utility of graphene for reduction of nosocomial infection in hospital settings is suggested.

Eugenol protects against citrinin-induced cytotoxicity and oxidative damages in cultured human colorectal HCT116 cells

This study aimed to investigate the protective effects of Eugenol (EUG), an effective antioxidant phenolic compound with a radical scavenging activity against citrinin (CTN)-induced toxicity in vitro using HCT116 cells. CTN is a well-known mycotoxin found in different constituents of the food chain. This environmental contaminant produces free radicals which interacts with cellular macromolecules and produces oxidation of protein, lipid, and DNA. The cytotoxic effects were monitored by measuring cell viability, reactive oxygen species (ROS) generation, antioxidant enzyme activities, malondialdehyde (MDA) production, protein oxidation, and DNA fragmentation. Our results have shown that the pretreatment of HCT116 cells with EUG, 2 h prior to citrinin (CTN) exposure, significantly decreased CTN-induced cell death, inhibited ROS generation, modulated activities of both catalase (CAT) and superoxide dismutase (SOD), and reduced MDA production. Level of protein-bound sulfhydryls and DNA fragmentation were also declined as compared with CTN-treated cells. These findings suggest that EUG would be an effective protective agent against CTN-induced oxidative stress, and thereby, it may complement and add to the functions of antioxidant vitamins and enzymes as a protection against the cytotoxicity of this mycotoxin.

Ochratoxin A levels in human serum and foods from nephropathy patients in Tunisia: where are you now?

Ochratoxin A is a natural mycotoxin with nephrotoxic properties that can contaminate food products. It has been detected in high amount in human serum collected from nephropathy patients, especially those categorized as having a chronic interstitial nephropathy of unknown etiology. In the present study, ochratoxin A levels were measured in commonly consumed food items and in serum samples from nephropathy and healthy subjects in Tunisia. To assess ochratoxin A, a high performance liquid chromatography method was optimized. The ochratoxin A assay showed very different scales of ochratoxin A serum and food contamination from 0.12 to 1.5 ng/mL and 0.11 to 6.1 ng/g respectively, and in healthy subjects and 0.11 to 33.8 ng/g for food and 0.12 to 3.8 ng/mL for serum in nephropathy patients suffering from chronic interstitial nephropathy of unknown etiology. The disease seems related to ochratoxin A serum levels and food contaminations, since the healthy group was significantly different from the nephropathy group (P<0.001) for both food and serum ochratoxin A contamination. Those results combined with data published already, emphasize the likely endemic aspect of ochratoxin A-related nephropathy occurring in Tunisia.

Health Effects of Mycotoxins: A Toxicological Overview

Diseases caused by fungi are spread by direct implantation or inhalation of spores. Fungi can cause adverse human health effects to many organ systems. In addition to infection and allergy, fungi can produce mycotoxins and organic chemicals that are responsible for various toxicologic effects. We reviewed the published literature on important mycotoxins and systemic effects of mycotoxins. Scientific literature revealed a linkage between ingesting mycotoxin contaminated food and illness, especially hepatic, gastrointestinal, and carcinogenic diseases. Issues related to mycotoxin exposure, specific diseases, and management are discussed. Although there is agreement that diet is the main source of mycotoxin exposure, specific health effects and risk assessment from indoor nonagricultural exposure are limited by the paucity of scientific evidence currently available. Further research on the health effects of inhaling mycotoxins in indoor settings is needed.

Ochratoxin A and human chronic nephropathy in Tunisia: is the situation endemic?

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is being increasingly considered as the main causal agent of Balkan endemic nephropathy (BEN), a fatal kidney disease associated with the end stage of urothelial tumours. However, despite the considerable amount of data, it is still controversial whether OTA plays a causative or only a subordinate role in the induction of this human nephropathy. Tunisia for years had to confront a very similar human nephropathy, which is tentatively called chronic interstitial nephropathy of unknown cause. This study tends firstly to consolidate the suspected link between this Tunisian chronic interstitial nephropathy (CIN) of unknown cause and the presence of OTA in the blood and food of such patients, and second to enlighten the endemic character of this particular nephropathy. Therefore, in four consecutive inquiries, performed within the period 1991-2000, blood and food OTA contaminations were assayed and compared for 954 nephropathy patients and 205 healthy subjects from the Tunisian general population. This survey was also designed to show that, although the whole population is likely to be exposed to OTA, specific people living in conditions showing similarities with the Balkans do have a kidney disease apparently linked to ochratoxin in food. The results showed that the highest incidences were found in patients with CIN of unknown cause. Indeed, the percentages of OTA-positive samples ranged from 93% to 100%, whereas it was only from 62% to 82% in healthy subjects. Mean OTA concentrations were also higher in patients with CIN of unknown cause than in controls (44.4 +/- 19 microg/L to 55.6 +/- 19 microg/L as opposed to 1.22 +/- 1.2 microg/L to 3.35 +/- 2.32 microg/L, respectively). This study emphasizes further the implication of OTA on this particular human nephropathy and underlines the probable causative role of OTA in the onset of this disease. It is important to note that the highest levels of food OTA contamination were found in the group presenting with CIN of unknown cause, indicating that, similar to the case in the Balkans, people are exposed to OTA essentially by their food.

Karyomegaly of tubular cells as early stage marker of the nephrotoxicity induced by ochratoxin A in rats

Cases of karyomegaly were described by Sclare and by Mihatch in patients affected with tubular-interstitial nephropathy. The Karyomegalic cells showed enlarged nuclei with accumulation of genetic material. No aetiology was suggested. Our study of rats experimentally intoxicated by ochratoxin A, a well-known nephrotoxic compound, indicates the presence of karyomegaly with alteration of the tubular tissue. In control animals no karyomegalic cells were detected. These observations suggest that karyomegaly with megacytosis may be caused by the nephrotoxic ochratoxin A in the kidney. In addition abnormal mitosis together with karyomegalic cells were observed at an earlier stage of the intoxication (30 days) suggesting possible regeneration if the OTA insults are stopped. After 90 days of treatment, the degeneration increased and only karyomegalic and apoptotic-like cells were observed indicating that the regeneration no longer occurs and that the degeneration becomes irreversible.

Epidemic of fatal encephalopathy in preschool children in Burkina Faso and consumption of unripe ackee (Blighia sapida) fruit

BACKGROUND

On March 21, 1998, the Regional Health Authority of Bobo-Dioulasso, Burkina Faso, asked the Centre Muraz to investigate an unexplained outbreak of epidemic fatal encephalopathy (EFE). We aimed to identify the cause of this epidemic.

METHODS

We identified cases retrospectively through review of health-service records and interviews of family members, village chiefs, and local healers. Active surveillance was started in administrative divisions within the study area in April, 1998, to identify further EFE cases. We did a case-control study of households to investigate the risk from various environmental and health factors. Blood and urine samples were collected if possible and urine dicarboxylic acid concentrations measured by gas chromatography.

FINDINGS

29 cases of EFE were identified from January to May, 1998. Estimated age-specific attack rates (2-6 years) ranged from 31 to 847 per 100,000 population (p<0.001). The most common symptoms were hypotonia, vomiting, convulsions, and coma. All children died in 2-48 h. The only factor associated with EFE was the presence of ackee trees (Blighia sapida) within 100 m of households (odds ratio 5.1 [95% CI 1.8-14.7] p=0.001). Poisoning with unripe ackee fruits was suggested by urine concentrations of dicarboxylic acids four to 200 times higher in cases (n=2) than in controls (n=3).

CONCLUSION

Consumption of unripe ackee fruit probably caused this epidemic and may lead to a substantial number of unexplained deaths in preschool children in west Africa every year. Educational campaigns have the potential to prevent these deaths.

In vitro toxicity of trichothecenes on human erythroblastic progenitors

Trichothecenes are mycotoxins produced by various species of fungi which can occur on various agricultural products. Among these compounds, T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS) and deoxynivalenol (DON) are the most naturally encountered and potent trichothecenes. Consumption of trichothecene contaminated foods by farm animals and humans leads to mycotoxicoses. Trichothecenes are known to induce haematologic disorders such as neutropenia, thrombopenia, and aplastic anemia in human and animals. The aim of our investigations is to explore the effects of trichothecenes on the haematopoietic progenitors. The four trichothecenes previously demonstrated to be strongly cytotoxic for human CFU-GM have been tested on human BFU-E. For this purpose, a culture model of human erythroblastic progenitors (BFU-E) optimized for toxicological studies was used to determine the effects of T-2, HT-2, diacetoxyscirpenol (DAS) and deoxynivalenol (DON) on red blood cell precursor proliferation and differentiation. Results showed that human BFU-E are as sensitive to trichothecenes as human CFU-GM, except for DON, in the range of concentrations tested. Differentiation of erythroblastic progenitors could be perturbed by these mycotoxins. Human erythroblastic progenitors are also a target of trichothecenes.

Foodstuffs and human blood contamination by the mycotoxin ochratoxin A: correlation with chronic interstitial nephropathy in Tunisia

Ochratoxin A (OTA) has been detected in high amounts in human blood samples collected in nephrology departments in Tunisia from nephropathy patients under dialysis, especially those categorised as having a chronic interstitial nephropathy of unknown aetiology. These represent 12-26.1% of all chronic renal failure patients. To clarify the situation, food and blood samples were collected from nephropathy patients and controls, (with no familial case of nephropathy). The OTA assay showed very different scales of OTA food and blood contamination from 0.1 to 16.6 micrograms/kg and 0.1-2.3 ng/ml, respectively, in controls and healthy individuals and 0.3-46 830 micrograms/kg for food and 0.7-1136 ng/ml for blood in nephropathy patients. The disease seems related to OTA blood levels and food contaminations, since the control group was significantly different from the nephropathy group (p < 0.005) for both food and blood ochratoxin A contamination. Combined with data published already, the results emphasize the likely endemic aspect of this OTA-related nephropathy occurring in Tunisia and possibly in other countries of northern Africa. This nephropathy is very similar to Balkan endemic nephropathy.

Comparison of toxicity induced by T-2 toxin on human and rat granulo-monocytic progenitors with an in vitro model

T-2 toxin is a trichothecene mycotoxin produced by various species of fungi. Trichothecenes are known as major contaminants of cereals and their derivatives. In man as well as in animals, T-2 toxin has been shown to induce alimentary intoxication and, among others, haematological symptoms. Granulo-monocytic progenitors from human umbilical cord blood on the one hand and granulo-monocytic progenitors from rat bone marrow on the other, were cultured in the presence of T-2 toxin (from 10(-7) to 10(-10) M) for 14 days. A study of concentration and effect relationships showed a strong and rapid effect of T-2 toxin on rat colony forming unit-granulocyte and macrophage (CFU-GM) between 5 x 10(-9) M and 10(-9) M. On the other hand, human CFU-GM were able to grow in the presence of the same T-2 toxin concentrations. IC50 were determined on day 7, 10 and 14. They were, respectively, 1.6 x 10(-9) M; 3.6 x 10(-9) M; 1.4 x 10(-9) M for human cells, and 2.2 x 10(-9) M; 3.3 x 10(-9) M; 2.6 x 10(-9) M for rat cells. The present study was prompted by the need to define precisely the cytotoxic and inhibitory T-2 toxin concentrations for rat and human CFU-GM. It is particularly relevant for the investigation of cellular T-2 toxin targets and in order to elucidate the mechanism of trichothecene haematotoxicity.

Ochratoxin A in human blood in relation to nephropathy in Tunisia

The determination of ochratoxin A (OTA) in human blood in Tunisian populations is underway. The range of contamination is between 0.7 to 7.8 ng ml-1 for the general population and 12 to 55 ng ml-1 for people suffering from chronic renal failure. It appears that 21 to 64% of people suffering from nephropathy are OTA positive with a detection limit of 1ng ml-1. This situation prompted us to search for possible association of OTA contamination and nephropathy resembling Balkan endemic nephropathy. The classification of the ill population into chronic interstitial nephropathy (CIN), chronic glomerular nephropathy (CGN), chronic vascular nephropathy (CVN) and others, indicated that the largest is the CIN group which is significantly different from the other groups, and from the control (P < 0.005). Furthermore, it presented the highest OTA mean values (25 to 59 ng ml-1) compared with the control, CGN, CVN and other groups (6 to 18 ng ml-1) according to the designated region in Tunisia. The rural population seems to be more exposed to ochratoxins in Tunisia, as has been previously reported in the Balkans and Western Europe. Altogether, these results emphasise that in Tunisia an endemic ochratoxin-related nephropathy is probably occurring.

Reye's and Reye-like syndromes, drug-related diseases? (causative agents, etiology, pathogenesis, and therapeutic approaches)

In the literature the separation between RS and RLS is confusing and makes it difficult to plan an appropriate preventive action or to develop new therapeutic approaches. We suggest that the generalized damage and encephalopathy seen in both RS and RLS may be due to a wide variety of causative agents that contribute to a common derangement, principally involving mitochondrial oxidative pathway. Fasting status and infections increase the catabolism and the subsequent flux of metabolites from peripheral tissues to the liver (FA and amino acids); cytokines (TNF, IL-1, and IL-6), in particular, mediate this effect during infection and experimental endotoxemia. Some drugs and other toxic compounds induce functional and morphological liver mitochondrial derangement. Oxidative metabolism is impaired, with subsequent stimulation of alternative pathways of oxidation, following production of unusual toxic acyl CoAs and dicarboxylic acids. Toxic compounds accumulate in the liver, deranging its functions and causing energy depletion, and are also released in the circulation from which they reach other tissues, including the brain. Neurons and astrocytes in the brain may be affected differently: Neurons suffer from the lack of energy and the effect of toxic compounds arriving from the bloodstream, and astrocytes may be directly affected by the beta-oxidation derangement. Very important may be genetic predisposition, which, by making the patient more sensitive to a particular causative agent, may facilitate the onset of RS and RLS. The therapeutic approach is, presently, mainly symptomatic, directed as it is to counteracting each alteration shown, depending by the clinical gravity. Other pharmacological approaches are only studied experimentally, like carnitine supplementation and PGE2 administration, or theoretically envisaged, like monoclonal antibody therapy directed at LPS or at pro-inflammatory cytokines or treatment with interferon-alpha.

Isolation and structure determination of natural analogues of the mycotoxin ochratoxin A produced by Aspergillus ochraceus

Three new natural mycotoxins, analogues of ochratoxin A, in which the phenylalanine moiety is replaced by serine, hydroxyproline or lysine, were isolated from cultures of Aspergillus ochraceus by TLC followed by HPLC column chromatography. Their structures were determined after acidic hydrolysis by the characterisation of both their amino acid moieties and of ochratoxin alpha, the chlorinated dihydroisocoumarin moiety of ochratoxin A. These structures were confirmed by mass spectrum analysis.

Protein synthesis inhibition and cardiac lesions associated with deoxynivalenol ingestion in mice

Deoxynivalenol (DON), an occasional contaminant of foodstuffs, has been implicated in outbreaks of mycotoxicosis. Balb-c mice that had ingested 0.35 mg/kg of DON showed a drastic decrease in food intake and concomitant loss of weight. Severe depletion of the lymphoid organs and liver were also observed. Cardiac lesions, appeared as calcified pericarditis foci in young animals fed a diet contaminated by 10 to 20 ppm of DON for a period of a few weeks. DON inhibited protein synthesis. This inhibition occurred at lower doses for the heart than for the other organs. This preferential effect on cardiac tissue correlated with the cardiotoxicity observed.