Intermediate-duration toxicity study of patulin in rats

Effects of Selenium Nanoparticles on Preventing Patulin-Induced Liver, Kidney and Gastrointestinal Damage

Patulin (PAT) is a toxic fungal metabolite, and oxidative damage was proved to be its important toxicity mechanism. Selenium nanoparticles (SeNPs) were prepared by reducing sodium selenite with chitosan as a stabilizer and used for preventing PAT-induced liver, kidney and gastrointestinal damage. SeNPs have good dispersibility, in vitro antioxidant activity, and are much less cytotoxic than sodium selenite. Cell culture studies indicated that SeNPs can effectively alleviate PAT-induced excessive production of intracellular ROS, the decline of glutathione peroxidase activity, and the suppression of cell viability. Evaluation of serum biochemical parameters, histopathology, oxidative stress biomarkers and activities of antioxidant enzymes in a mouse model showed that pre-treatment with SeNPs (2 mg Se/kg body weight) could ameliorate PAT-induced oxidative damage to the liver and kidneys of mice, but PAT-induced gastrointestinal oxidative damage and barrier dysfunction were not recovered by SeNPs, possibly because the toxin doses suffered by the gastrointestinal as the first exposed tissues exceeded the regulatory capacity of SeNPs. These results suggested that a combination of other strategies may be required to completely block PAT toxicity.

Mycotoxins and the Enteric Nervous System

Mycotoxins are secondary metabolites produced by various fungal species. They are commonly found in a wide range of agricultural products. Mycotoxins contained in food enter living organisms and may have harmful effects on many internal organs and systems. The gastrointestinal tract, which first comes into contact with mycotoxins present in food, is particularly vulnerable to the harmful effects of these toxins. One of the lesser-known aspects of the impact of mycotoxins on the gastrointestinal tract is the influence of these substances on gastrointestinal innervation. Therefore, the present study is the first review of current knowledge concerning the influence of mycotoxins on the enteric nervous system, which plays an important role, not only in almost all regulatory processes within the gastrointestinal tract, but also in adaptive and protective reactions in response to pathological and toxic factors in food.

The characteristics, occurrence, and toxicological effects of patulin

Mycotoxins are the secondary metabolites secreted by different types of fungi to which humans can get exposed mainly via ingestion. Patulin (C₇H₆O₄) is a polyketide lactone produced by various fungal specifies, including Penicillium expansum as the main producer. P. expansum can infect different fruits and vegetables yet it has preference to apples in which they cause blue rot. Therefore, apples and apple-based food products are the main source of Patulin exposure for humans. Patulin was first identified in 1943 under the name of tercinin as a possible antimicrobial agent. Although it is categorized as a non-carcinogen, Patulin has been linked, in the last decades, to neurological, gastrointestinal, and immunological adverse effects, mainly causing liver and kidney damages. In this review, the characteristics of and possible human exposure pathways to Patulin are discussed. Various surveillance and toxicity studies on the levels of Patulin in various food products and effects of Patulin on cells and animal models have been documented as well. Importance of epidemiological studies and a summary of the possible toxicity mechanisms are highlighted with a case study. The commonly used control methods as described in the literature are also discussed to guide future researchers to focus on mitigating mycotoxins contamination in the food industry.

In vitro antitumor activity of patulin on cervical and colorectal cancer cell lines

Background and Purpose:

Patulin is a mycotoxin produced by some molds, especially Aspergillus and Penicilium, and is responsible for mycotoxicosis in animals and humans.

There is still not very detailed data about the anti-cancer potency of patulin, but some reports demonstrated that it induces cellular apoptosis and toxicity.

Materials and Methods:

To determine the efficacy of patulin as a therapeutic strategy for cervical and colorectal cancers, we investigated its effects on HeLa,SW-48, and MRC-5 cell lines. Cell lines were exposed to various concentrations of patulin (i.e., 0.5, 1, 2, and 4 µM), then using methyl thiazolyl tetrazolium (MTT) and bromo-2′-deoxyuridine (BrdU) assays, the rates of apoptosis and cell viability were determined.

Results:

The obtained results showed a significant reduction in cell viability and apoptosis induction in a dose-dependent manner. Among all the cell lines, the highest growth inhibition rate was obtained at the 4 μM concentration of patulin.

Conclusion:

Our results suggested that patulin could significantly decrease tumor growth in human cervical and colorectal cancer models.

In vitro antitumor activity of patulin on cervical and colorectal cancer cell lines

BACKGROUND AND PURPOSE

Patulin is a mycotoxin produced by some molds, especially Aspergillus and Penicilium, and is responsible for mycotoxicosis in animals and humans.There is still not very detailed data about the anti-cancer potency of patulin, but some reports demonstrated that it induces cellular apoptosis and toxicity.

MATERIALS AND METHODS

To determine the efficacy of patulin as a therapeutic strategy for cervical and colorectal cancers, we investigated its effects on HeLa,SW-48, and MRC-5 cell lines. Cell lines were exposed to various concentrations of patulin (i.e., 0.5, 1, 2, and 4 µM), then using methyl thiazolyl tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays, the rates of apoptosis and cell viability were determined.

RESULTS

The obtained results showed a significant reduction in cell viability and apoptosis induction in a dose-dependent manner. Among all the cell lines, the highest growth inhibition rate was obtained at the 4 μM concentration of patulin.

CONCLUSION

Our results suggested that patulin could significantly decrease tumor growth in human cervical and colorectal cancer models.

Correlation of chemical structure with reproductive and developmental toxicity as it relates to the use of the threshold of toxicological concern

In the absence of toxicological data on a chemical, the threshold of toxicological concern (TTC) approach provides a system to estimate a conservative exposure below which there is a low probability of risk for adverse health effects. The original toxicology dataset underlying the TTC was based on NOELs from repeat dose studies. Subsequently there have been several efforts to assess whether or not these limits are also protective for reproductive/developmental effects. This work expands the database of chemicals with reproductive and developmental data, presents these data in a comprehensive and transparent format and groups the chemicals according to the TTC "Cramer Class" rules. Distributions of NOAELs from each of these classes were used to assess whether the previously proposed TTC values based on repeat dose data are protective for reproductive/developmental toxicity endpoints as well. The present analysis indicates that, for each Cramer Class, the reproductive and developmental endpoints would be protected at the corresponding general TTC tiers derived by Munro et al. (1996).

Biosynthesis and toxicological effects of patulin

Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects.

Variability and uncertainty assessment of patulin exposure for preschool children in Flanders

The objective of the present study was to evaluate the patulin exposure of children consuming organic, handcrafted or conventional apple juice through a probabilistic approach and to evaluate the effectiveness of several risk management options aiming to reduce the risk for children due to patulin exposure. However, a large part of the data on patulin contamination of apple juice fell under the limit of detection (LOD). Different methods were tested to deal with these so-called left censored data and a uniform distribution with uncertain bounds was selected to handle this censorship. Variability and uncertainty assessment of patulin exposure showed that 0.9% [90% confidence interval (CI): 0.3-1.8%] of the children consuming only organic apple juice exceed the tolerable daily intake (TDI). For consumers of conventional and handcrafted apple juice this was respectively 0.1% [90% CI: 0-0.3%] and 0% [90% CI: 0-0.2%]. Reduction of the patulin contamination in apple juice to concentrations below 25 microg/kg reduced the percentage of the children exceeding the TDI to 0% [90%CI: 0-0.2%] for organic apple juice. Reduction of the apple juice consumption was less effective than a reduction of the patulin concentration in apple juice and is only useful when the patulin concentration of apple juice is below 25 microg/kg.

A new competitive fluorescence assay for the detection of patulin toxin

Patulin is a toxic secondary metabolite of a number of fungal species belonging to the genera Penicillum and Aspergillus. It has been mainly isolated from apples and apple products contaminated with the common storage-rot fungus of apples, Penicillum expansum, but it has also been extracted from rotten fruits, moldy feeds, and stored cheese. Human exposure to patulin can lead to serious health problems, and according to a long-term investigation in rats, the World Health Organization has set a tolerable weekly intake of 7 ppb body weight. The content of patulin in foods has been restricted to 50 ppb in many countries. Conventional analytical detection methods involve chromatographic analyses, such as HPLC, GC, and, more recently, techniques such as LC/MS and GC/MS. However, extensive protocols of sample cleanup are required prior to the analysis, and to accomplish it, expensive analytical instrumentation is necessary. An immunochemical analytical method, based on highly specific antigen-antibody interactions, would be desirable, offering several advantages compared to conventional techniques, i.e., low cost per sample, high selectivity, high sensitivity, and high throughput. In this paper, the synthesis of two new derivatives of patulin is described, along with their conjugation to the bovine serum albumin for the production of polyclonal antibodies. Finally, a fluorescence competitive immunoassay was developed for the on-line detection of patulin.

Absorption of the mycotoxin patulin from the rat stomach

The mycotoxin patulin (PAT), which frequently occurs in apple juices, has previously been shown to be toxic and teratogenic. However, there is almost no data about its absorption and metabolism. Therefore, the enrichment of PAT in the tissue of perfused rat stomachs after luminal application and its vascular appearance was quantified by stable isotope dilution assays. After application of juices enriched with PAT at concentrations of 350 and 3.5 mg/l, respectively, the mycotoxin appeared almost instantly in the perfusate. Twenty-six to twenty-nine percent of PAT were removed from the gastric lumen over 55 min. From this quantity, 17% and 2% were transferred into vascular circulation and 3% and 0.06% were detectable in gastric tissue for the high and the low PAT dose, respectively. The disappearance of 8400 microg and 700 microg PAT, respectively, could be attributed in part to its reaction with intracellular glutathione (GSH). Regarding the GSH content in the tissue, a decrease of 87% compared to that of control stomachs was observed for the high PAT dose, whereas in the case of the low PAT dose no significant GSH degradation occurred. Thus our results show that even low concentrations of patulin penetrate the gastric wall. Toxic effects, however, are unlikely as most of the patulin is disintegrated.

Subacute toxicity study of patulin in the rat: effects on the kidney and the gastro-intestinal tract

Female and male Wistar rats were given drinking-water containing patulin at concentrations of 0, 24, 84 or 295 mg/litre citrate buffer (1 mM) for 4 wk. Compared with the controls, there were decreases in food and liquid intake by rats given the mid and high doses of patulin and the body weights of rats in the high-dose group were also decreased. The creatinine clearance in the high-dose group was lowered, although morphological glomerular damage was not observed. In the high-dose group, fundic ulcers in the stomach and enlargement and activation of the pancreatico-duodenal lymph nodes were noticed, while villous hyperaemia in the duodenum was observed in the mid- and high-dose groups. From the present data it can be concluded that high doses of patulin, administered via the drinking-water, caused effects on the kidney and gastro-intestinal tract. Since no changes in the relative weight or histological appearance of the adrenal glands were observed, it is suggested that the fundic ulcers in the stomach were caused by a direct effect of patulin and not indirectly (i.e. by stress).

Patulin mycotoxicosis in the rat: toxicology, pathology and clinical pathology

Patulin, a secondary metabolite produced by species of the genera Penicillium and Aspergillus, was administered to male Sprague-Dawley rats, weighing 50-60 g, by the oral, sc and ip routes. The 72-hr LD50 values (in mg/kg weight) were: oral, 55.0; sc, 11.0; ip, 10.0. Mortality was greatest 0-24 hr after administration by the oral and sc routes and 49-72 hr after ip dosing. Gross alterations consisted of gastric and intestinal hyperaemia and distention. Histopathological alterations consisted principally of ulceration and inflammation of the stomach. Patulin was administered orally to rats daily or every other day for 2 wk at doses of 50 or 75% of the oral LD50. Mortality in the treated groups was greater than in controls but was similar for all treated groups. No evidence of cumulative toxicity was found and the gross and histopathological alterations were similar to those found in the LD50 studies. Clinicopathological alterations included metabolic alkalosis with respiratory compensation, oliguria, decreased serum sodium, elevated blood glucose, reduced plasma protein and an elevated total leucocyte count which differential leucocyte counts indicated to be due to neutrophilia. The inflammatory alterations observed in the gastro-intestinal tract may be due to the irritant properties of patulin or to an alteration in the gastro-intestinal flora by the antibiotic activity of patulin.

Long-term carcinogenicity and toxicity studies of patulin in the rat

Patulin is a mycotoxin produced by a variety of Penicillium and Aspergillus species which are likely natural contaminants of various foods. The present study was conducted to determine the effects of lifetime administration of patulin in FDRL Wistar rats. Animals received patulin by gastric intubation three times per week at the level of 0.0, 0.1, 0.5 and 1.5 mg per kg body weight. The animals used in this lifetime study were derived from F0 parents exposed to equivalent levels of patulin for 4 weeks before mating, and throughout mating, gestation and lactation. Patulin treatment at 0.5 and 1.5 mg kg-1 to male rats caused a significant decrease in body weight gain in comparison to controls. Body weights of treated female rats were similar to that of control rats. No consistent significant differences among groups were noted in the hematology, clinical chemistry or urine analysis parameters measured during or at the termination of the study. Patulin administered to male and female rats at 1.5 mg kg-1 caused a significantly increased mortality rate as compared to respective control animals. The cause of death appeared to be increased pulmonary and laryngotracheal inflammation. No tumorigenic effect of patulin was observed.

Mutagenicity to Salmonella typhimurium of some Aspergillus and Penicillium mycotoxins

17 mycotoxins produced by various Aspergillus and Penicillium species were screened for their mutagenic activity to Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, both with and without metabolic activation. Austdiol, austocystins A and D, kojic acid and viridicatumtoxin were found to be mutagenic after metabolic activation, while austdiol was also mutagenic per se. Aflatoxin B1, sterigmatocystin and versicolorin A, which were used as positive controls were also mutagenic. No mutagenic activity was evident in the case of citrinin, cyclopiazonic acid, fumitremorgen B, griseofulvin, luteoskyrin, O-methylsterigmatocystin, mycophenolic acid, ochratoxin A, patulin, penicillic acid, secalonic acid D and TR2-toxin. A good relationship was found between the mutagenic activity, or lack of it, of most of the mycotoxins with existing data on carcinogenicity. Inadequate information on the carcinogenicity of austdiol, austocystins A and D, kojic acid and viridicatumtoxin precluded correlations with mutagenicity to S. typhimurium. The relationship between chemical structure and mutagenicity of the mycotoxins is discussed.

Teratogenic and dominant lethal studies of patulin in mice

Teratogenicity of daily intraperitoneal (i.p.) injections of 1.5 or 2.0 mg/kg of patulin on days 6 through 17 of pregnancy and mutagenic effects of acute i.p. exposure of 3.0 mg/kg of patulin on male germ cells were evaluated. Resorption of all implanted embryos occurred at 2.0 mg/kg/day of patulin, while a significant reduction in the average body weight of 19-day-old fetuses from patulin-treated mothers, compared to control fetuses, was noticed at 1.5 mg/kg/day without any lethal effects on the implanted embryos. Patulin was embryocidal, possibly fetotoxic but was neither teratogenic nor mutagenic to mice.

Absorption, distribution, and excretion of [14C]patulin by rats

Adult rats of both sexes were given a single oral dose of [14C] patulin and were sacrificed at various time intervals from 4 hr to 7 days following administration of the mycotoxin. Two groups of rats were employed; the treated group had been exposed to daily oral doses of unlabeled patulin (dissolved in pH 5.0 citrate buffer) in utero and for 41-66 wk after weaning, while the controls were given the buffer only throughout gestation and for 38-81 wk after weaning. Approximately 49% of the administered 14C radioactivity was recovered from feces and 36% from urine within 7 days after dosing. Most of the excretion of labeled material occurred within the first 24 hr. All of the 14C activity detected in the urine samples was either metabolites and/or conjugates of the original [14C]patulin. About 1-2% of the total radioactivity was recovered as 14CO2 from expired air. Carbon-14 radioactivity in various tissues and organs was determined throughout the 7 day period; the most significant retention site was the red blood cells.