An approach to the toxicity and toxicokinetics of aflatoxin B1 and ochratoxin A after simultaneous oral administration to fasted F344 rats

Humans are exposed to the hepatotoxic aflatoxin B1 (AFB1) and nephrotoxic ochratoxin A (OTA) through diet. However, kinetic and toxicological data after their co-administration are scarce. In this study, a single oral dose of AFB1 (0.25mg/kg bw)+OTA (0.5mg/kgbw) was administered to fasted F344 rats. Blood, liver and kidney were harvested at different timepoints for mycotoxins quantification, relative weight calculation, clinical biochemistry and histopathology analysis. Toxicity parameters pointed to acute toxicity in liver due to AFB1. No remarkable toxicity was observed in kidneys or immunological organs. Maximum observed concentrations in plasma (C(max)) were at 10min and 2h for AFB1 and OTA, respectively. AFB1 plasma concentration could indicate a rapid absorption/ metabolism of the mycotoxin; and AFB1 liver and kidney concentrations were lower than LOQ and LOD, respectively. For OTA, C(max) was 4326.2μg/L in plasma. In kidney and liver C(max) was reached at 8h and concentrations were very similar between both organs at all timepoints. Due to the low levels of AFB1, the effect of OTA on AFB1 kinetics could not be assessed. However, AFB1 seems not to affect OTA kinetics, as its profile seems very similar to kinetic studies performed only with OTA in similar conditions

Validation of a UHPLC-FLD method for the simultaneous quantification of aflatoxins, ochratoxin A and zearalenone in barley

A fast and simple UHPLC-FLD method has been developed for the simultaneous determination in barley of aflatoxins (B1, G1, B2 and G2), ochratoxin A (OTA) and zearalenone (ZEA), some of the most important mycotoxins due to their toxicity and occurrence. The procedure is based on the extraction of the six mycotoxins with a mixture of acetonitrile and water, and the purification of the extract with immunoaffinity columns before analysis. Detection of AFB1 and AFG1 is improved using a photochemical reaction. The method has been validated with satisfactory results. Limits of detection were 340 ng kg-1 for ZEA, 13 ng kg-1 for OTA and varied from 0.5 to 15 ng kg-1 for aflatoxins. Recovery percentages were between 78.2 and 109.2%. After being validated, the method has been successfully applied to 20 barley samples cultivated in a region of northern Spain (Navarra)

Validation of a UHPLC-FLD analytical method for the simultaneous quantification of aflatoxin B1 and ochratoxin a in rat plasma, liver and kidney

A rapid and simple method for the simultaneous quantification of AFB1 and OTA in rat plasma, liver and kidney by UHPLC-FLD has been successfully validated according to the following criteria: selectivity, stability, linearity, precision, accuracy, recovery, robustness and limits of quantification and detection. The extraction method, calibration curves and chromatographic conditions are common for the three matrices. Plasma and homogenized tissue samples (100 μL) were extracted with acetonitrile-formic acid mixture (99:1) (300 μL). Chromatographic separation was performed with a mixture of water and acetonitrile:methanol (50:50), both acidified with 0.5% of formic acid using a gradient profile. The method avoids the use of immunoaffinity columns and allows reduction of sample and solvent volumes as well as toxic wastes. The detection is based on a photochemical reaction which enhances the AFB1 response without affecting the OTA signal before reaching the fluorescent detector. The mycotoxin recovery for each matrix was very efficient, between 93% and 96% for AFB1 and between 94% and 96% for OTA. For both mycotoxins the LOQs were 2 μg/L in plasma and 8 μg/kg in liver and kidney. The method has successfully been applied to rat samples after a single oral administration of a mixture of AFB1 and OTA and it could be a useful tool in toxicokinetic and toxicological studies

Effects of fasting and gender on ochratoxin A toxicokinetics in F344 rats

Ochratoxin A (OTA) is a mycotoxin that causes renal tumors in rats, particularly in males. In previous kinetic studies performed in fed conditions (Vettorazzi et al., 2008), mature F344 male rats presented a significantly lower OTA bioavailability than females and young animals. The objective of the present study was to evaluate two factors which could explain this different kinetic profile: the presence of food and the male-specific protein alpha-2u-globulin. Therefore, a 24h kinetic study has been performed in rats under fasting conditions. Food ingestion has been controlled in both sexes during two months. The presence of alpha-2u-globulin in the urine has been analyzed with SDS-gradient mini-gel electrophoresis. Fasting tends to increase the maximum OTA plasma concentrations and the rate of absorption. The relative bioavailability is significantly increased under fasting conditions only in males. Mature males consumed a higher amount of food but, as the OTA dose administered, it was proportional to body weight. The reason why the OTA bioavailability is more affected in presence of food only in males is unclear. Several possibilities, such as differences in gastric emptying, OTA-food interactions and the involvement of alpha-2u-globulin are discussed

Genotoxicity of aflatoxin B1 and ochratoxin A after simultaneous application of the in vivo micronucleus and comet assay

Aflatoxin B1 (AFB1) and Ochratoxin A (OTA) are genotoxic mycotoxins that can contaminate a variety of foodstuffs, the liver and the kidney being their target organ, respectively. The micronucleus (MN) assay (bone marrow) and the comet assay (liver and kidney) were performed simultaneously in F344 rats, treated with AFB1 (0.25 mg/kg b.w.), OTA (0.5 mg/kg b.w.) or both mycotoxins. After AFB1 treatment, histopathology and biochemistry analysis showed liver necrosis, focal inflammation and an increase in Alanine Aminotransferase and Aspartate Aminotransferase. OTA alone did not cause any alteration. The acute hepatotoxic effects caused by AFB1 were less pronounced in animals treated with both mycotoxins. With regard to the MN assay, after 24h, positive results were obtained for AFB1 and negative results were obtained for OTA, although both toxins caused bone marrow toxicity. In the combined treatment, OTA reduced the toxicity and the number of MN produced by AFB1. In the comet assay, after 3h, positive results were obtained for AFB1 in the liver and for OTA in the kidney. The combined treatment reduced DNA damage in the liver and had no influence in the kidney. Altogether, these results may be indicative of an antagonistic relationship regarding the genotoxicity of both mycotoxins

Cuestiones interdisciplinares iltrapianto degli argani

Organ transplants do not constitute the point of arrival of bio-medical research. but rather a point of departure aimed at successive accomplishments at base research level or at the level of clinical applications. Those who considered transplants to be only a surgical task destined to slow down due to a lack of adequate immuno-biological knowledge have been surprised by the renewed vitality of this sector and by the amount of new adquisitions reached during these last few years. The results achieved in the branch of kidney transplants are a clear demonstration of this therapeutic reality. The substitution of other organs. on the other hand. is still clearly a problem today. but looking ahead ten years, however, we can perceive the development trend in this regard. Artificial organs, both temporary or definitive, intra-corporeal or extracorporeal, partially biological such as the liver or completely artificial, are being studied at an increasingly intensive pace and depth. After the first results -which have been deceiving- we now have word of positive results in the branch of liver and heart substitution. In this manner the complex sector of research on lung transplant -although still full of problems yet to be solved- sparks the interest of researchers who are endowed with a spirit of service and perseverence. Modern surgery has to be receptive to the adquisition of a greater amount of data facilitated by immuno-biological, physiopathological and pharmacological research, and integrated by the findings of bio-engineering, which are indispensible at the present moment. Such a task represents the updating of this sector, and includes the results achieved by sorne of the most important research centres in the world. This task. therefore, also constitutes an updating for all those who are interested in this new type of surgery

Cuestiones interdisciplinares iltrapianto degli argani

Organ transplants do not constitute the point of arrival of bio-medical research. but rather a point of departure aimed at successive accomplishments at base research level or at the level of clinical applications. Those who considered transplants to be only a surgical task destined to slow down due to a lack of adequate immuno-biological knowledge have been surprised by the renewed vitality of this sector and by the amount of new adquisitions reached during these last few years. The results achieved in the branch of kidney transplants are a clear demonstration of this therapeutic reality. The substitution of other organs. on the other hand. is still clearly a problem today. but looking ahead ten years, however, we can perceive the development trend in this regard. Artificial organs, both temporary or definitive, intra-corporeal or extracorporeal, partially biological such as the liver or completely artificial, are being studied at an increasingly intensive pace and depth. After the first results -which have been deceiving- we now have word of positive results in the branch of liver and heart substitution. In this manner the complex sector of research on lung transplant -although still full of problems yet to be solved- sparks the interest of researchers who are endowed with a spirit of service and perseverence. Modern surgery has to be receptive to the adquisition of a greater amount of data facilitated by immuno-biological, physiopathological and pharmacological research, and integrated by the findings of bio-engineering, which are indispensible at the present moment. Such a task represents the updating of this sector, and includes the results achieved by sorne of the most important research centres in the world. This task. therefore, also constitutes an updating for all those who are interested in this new type of surgery

Estudio de la toxicidad combinada de aflatoxina B1 y ocratoxina A en modelos "in vitro" e "in vivo"

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are two of the most prevalent mycotoxins that can be found in edible products. AFB1 has been classified as a human carcinogen; its mechanism of action, as a direct genotoxin, has been extensively studied. OTA is a potent carcinogen in rodents but the evidence in humans in not sufficient, and the genotoxic routes are not elucidated yet. According to the literature, more than one mycotoxin may occur together in the same food, human diet is varied and furthermore, the manufacturing process mixes together different raw materials, yielding totally new matrixes with a new risk profile. Due to the fact that humans and animals are exposed to a mixture of mycotoxins and the toxic effects of the possible combined associations are still unknown, the combined toxicity needs to be studied. In vitro, AFB1 was genotoxic with metabolic activation. DNA strand breaks and FPG sensitive sites were detected. However, OTA was not genotoxic under the same conditions. Co-exposure to a mixture of AFB1 and OTA reduced the genotoxicity of AFB1, in the direct strand breaks as well. In vivo, a kinetic study in rats showed that the absorption and metabolism of AFB1 molecule are extremely fast. It appears that the presence of AFB1 does not affect the kinetics of OTA because the maximum value and the kinetic profile observed were similar to those found in previous kinetic studies conducted on OTA under the same conditions. The presence of OTA decreased the acute hepatotoxicity of AFB1. The presence of OTA reduced cytotoxicity and the percentage of micronuclei induced by AFB1 in bone marrow. The comet assay made the detection of specific organ genotoxicity possible so that AFB1 significantly induced FPG sensitive sites in liver and ochratoxin A in kidney. The presence of ochratoxin A decreased DNA damage induced by aflatoxin B1 in the liver, although the co-exposure had no effect on the kidney. In general, the exposure to both toxins simultaneously resulted in a decrease of the genotoxicity of aflatoxin B1 in both in vitro and in vivo models

Estudio de la toxicidad combinada de aflatoxina B1 y ocratoxina A en modelos "in vitro" e "in vivo"

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are two of the most prevalent mycotoxins that can be found in edible products. AFB1 has been classified as a human carcinogen; its mechanism of action, as a direct genotoxin, has been extensively studied. OTA is a potent carcinogen in rodents but the evidence in humans in not sufficient, and the genotoxic routes are not elucidated yet. According to the literature, more than one mycotoxin may occur together in the same food, human diet is varied and furthermore, the manufacturing process mixes together different raw materials, yielding totally new matrixes with a new risk profile. Due to the fact that humans and animals are exposed to a mixture of mycotoxins and the toxic effects of the possible combined associations are still unknown, the combined toxicity needs to be studied. In vitro, AFB1 was genotoxic with metabolic activation. DNA strand breaks and FPG sensitive sites were detected. However, OTA was not genotoxic under the same conditions. Co-exposure to a mixture of AFB1 and OTA reduced the genotoxicity of AFB1, in the direct strand breaks as well. In vivo, a kinetic study in rats showed that the absorption and metabolism of AFB1 molecule are extremely fast. It appears that the presence of AFB1 does not affect the kinetics of OTA because the maximum value and the kinetic profile observed were similar to those found in previous kinetic studies conducted on OTA under the same conditions. The presence of OTA decreased the acute hepatotoxicity of AFB1. The presence of OTA reduced cytotoxicity and the percentage of micronuclei induced by AFB1 in bone marrow. The comet assay made the detection of specific organ genotoxicity possible so that AFB1 significantly induced FPG sensitive sites in liver and ochratoxin A in kidney. The presence of ochratoxin A decreased DNA damage induced by aflatoxin B1 in the liver, although the co-exposure had no effect on the kidney. In general, the exposure to both toxins simultaneously resulted in a decrease of the genotoxicity of aflatoxin B1 in both in vitro and in vivo models