Effects of Single and Repeated Oral Doses of Ochratoxin A on the Lipid Peroxidation and Antioxidant Defense Systems in Mouse Kidneys.

Ochratoxin-A (OTA) is a carcinogenic and nephrotoxic mycotoxin, which may cause health problems in humans and animals, and it is a contaminant in foods and feeds. The purpose of the present study is to evaluate the effect of oral OTA exposure on the antioxidant defense and lipid peroxidation in the kidney. In vivo administration of OTA in CD1, male mice (1 or 10 mg/kg body weight in a single oral dose for 24 h and repeated daily oral dose for 72 h or repeated daily oral dose of 0.5 mg/kg bodyweight for 21 days) resulted in a significant elevation of OTA levels in blood plasma. Some histopathological alterations, transcriptional changes in the glutathione system, and oxidative stress response-related genes were also found. In the renal cortex, the activity of the glutathione-system-related enzymes and certain metabolites of the lipid peroxidation (conjugated dienes, trienes, and thiobarbituric reactive substances) also changed.

Analyses of biomarkers of exposure to nephrotoxic mycotoxins in a cohort of patients with renal tumours.

The Czech Republic occupies the first place in the world in the frequency of renal and other urinary tract tumours, but their aetiology is unknown. To explore whether carcinogenic and nephrotoxic mycotoxins may contribute to kidney diseases in the Czech population, biomarkers of ochratoxin A (OTA) and citrinin (CIT) exposure were determined in biological specimens from a cohort of 50 patients with malignant renal tumours. Biomarker analyses in blood and urine samples used validated targeted methods for measuring OTA and CIT plus dihydrocitrinone (DH-CIT) after enrichment of analytes by specific immunoaffinity clean-up. OTA and CIT plus its metabolite DH-CIT were frequently detected in patient urine samples (OTA 62%; CIT 91%; DH-CIT 100%). The concentration ranges in urine were 1-27.8 ng/L for OTA, 2-87 ng/L for CIT and 2-160 ng/L for DH-CIT. The analyses of blood samples revealed also a frequent co-occurrence of OTA and CIT, in the ranges of 40-870 ng/L serum for OTA and 21-182 ng/L plasma for CIT. This first analysis of biomarkers in blood and urine samples of Czech patients revealed no major differences in comparison with published data for the general healthy Czech and European populations. Nonetheless, a frequent co-occurrence of CIT and OTA biomarkers in patient samples may be of interest with regard to potential interactions with other risk factors for renal disease.

Ochratoxin A and its metabolites in urines of German adults-An assessment of variables in biomarker analysis.

Ochratoxin A (OTA), a mycotoxin known for its nephrotoxic and carcinogenic properties, is a worldwide occurring contaminant in a variety of food commodities. Biomonitoring (i.e. analysis in biological fluids) can serve to assess human internal exposure from all consumed foods and beverages. We now determined the concentration of OTA and its metabolite ochratoxin alpha (OTα) in plasma and in urine of two male volunteers with different food habits, in order to assess intra-individual temporal fluctuations and inter-individual differences in their biomarker levels. Moreover, the urinary levels of both OTA and OTα were analyzed in a cohort of German adults (23 males, 27 females) on their regular diet. All samples were subjected to an enzymatic hydrolysis of biomarker conjugates prior to clean-up by liquid-liquid extraction and HPLC-FD analysis. The profile in the first individual showed small fluctuations over time: mean levels in plasma were 0.42 and 0.45ng/mL for OTA and OTα, respectively, and in urine means of 0.06ng/mL for both analytes. The other individual had mean levels of 1.64 and 0.20ng/mL for OTA and OTα in plasma, and 0.24 and 2.22ng/mL for these analytes in urine. It is concluded that inter-individual differences in biomarker levels reflect dissimilar dietary exposure and/or disposition of ingested mycotoxin, with an apparently more efficient detoxification of OTA to OTα in the second individual. In the German cohort (n=50), analytes were detected in 100% (OTA: range 0.02-1.82ng/mL mean level 0.21±0.31ng/mL) and 78% (OTα: range 0.01-14.25ng/mL, mean level 1.33±2.63ng/mL) of all urines. Parameters such as gender, age and body mass index did not show a significant association with urine biomarker levels. This study indicates frequent exposure to OTA among German adults. The new results are discussed in the context of biomarker data from other countries and some methodological issues.

Serum levels of ochratoxin A in dogs with chronic kidney disease (CKD): a retrospective study.

Ochratoxin A (OTA) is a mycotoxin produced by secondary metabolism of several fungi belonging to the genera Aspergillus and Penicillium. OTA is potentially nephrotoxic, neurotoxic, immunotoxic and carcinogenic in several animal species and in humans. This toxin has been detected in several human food and animal feed. The aim of this study was to determine OTA in blood samples of healthy and affected by chronic kidney disease (CKD) dogs. CKD group showed higher incidence of OTA-positivity than healthy dogs (96 vs. 56%) and a significantly higher median value of OTA plasma concentration (0.008 vs. 0.144 ng/ml). No significant correlation was observed between OTA levels and creatinine values in CKD dogs. This is the first study regarding OTA detection in plasma samples of healthy and CKD dogs; the presence of this toxin is higher in nephropatic patients but is not yet clear, if it is correlated with progression of the disease.

A fluorescent aptasensor based on a DNA pyramid nanostructure for ultrasensitive detection of ochratoxin A.

Analytical techniques for detection of ochratoxin A (OTA) in food products and blood serum are of great significance. In this study, a fluorescent aptasensor was developed for sensitive and specific detection of OTA, based on a DNA pyramid nanostructure (DPN) and PicoGreen (PG) dye. The designed aptasensor inherits characteristics of DPN, such as high stability and capacity for PG loading. PG, as a fluorescent dye, could bind to double-stranded DNA (dsDNA). In the absence of OTA, the pyramid structure of DPN remains intact, leading to a very strong fluorescence emission. Because of higher affinity of aptamer for its target relative to its complementary strand, upon addition of target, the pyramid structure of DPN is disassembled, leading to a weak fluorescence emission. The presented aptasensor showed high specificity toward OTA with a limit of detection (LOD) as low as 0.135 nM. Besides, the designed sensing strategy was successfully utilized to recognize OTA in serum and grape juice with LODs of 0.184 and 0.149 nM, respectively.

Maternal-Fetal Cancer Risk Assessment of Ochratoxin A during Pregnancy.

Increasing evidence has demonstrated that in utero exposure to environmental chemicals may interfere with fetal development and increase the risk of disease and cancer development later in life. Ochratoxin A (OTA) has been proven to induce diverse toxic effects including teratogenicity, carcinogenicity, immunotoxicity and potential endocrine disruption. Due to the continuous and widespread occurrence of OTA as a potential contaminant of staple foods, there is increasing concern of in utero exposure of fetus to this mycotoxin. In this study, maternal-fetal risk assessment of OTA during pregnancy was conducted using the benchmark dose approach for genotoxic carcinogens. The daily intake of OTA for Egyptian pregnant women was estimated based on their serum OTA level using the refined Klaassen equation for pregnancy. Fetal exposure level was also estimated based on the maternal data. Comparison between the estimated daily exposure and the negligible cancer risk intake (NCRI), and the calculation of margin of exposure (MOE) implicated that OTA exposure from dietary intake would be of low health concern for this general subpopulation of Egyptian women. This subpopulation of pregnant women was generally estimated not to be in high-risk for toxicity induced by OTA.

Biomonitoring using dried blood spots: detection of ochratoxin A and its degradation product 2'R-ochratoxin A in blood from coffee drinkers.

SCOPE: In this study, human exposure to the mycotoxin ochratoxin A (OTA) and its thermal degradation product 2'R-ochratoxin A (2'R-OTA, previously named as 14R-Ochratoxin A [22]) through coffee consumption was assessed. LC-MS/MS and the dried blood spot (DBS) technique were used for the analysis of blood samples from coffee and noncoffee drinkers (n = 50), and food frequency questionnaires were used to document coffee consumption. METHODS AND RESULTS: For the detection of OTA and 2'R-OTA in blood, a new sensitive and efficient sample preparation method based on DBS was established and validated. Using this technique 2'R-OTA was for the first time detected in biological samples. Comparison between coffee drinkers and noncoffee drinkers showed for the first time that 2'R-OTA was only present in blood from the first group while OTA could be found in both groups in a mean concentration of 0.21 µg/L. 2'R-OTA mean concentration was 0.11 µg/L with a maximum concentration of 0.414 µg/L. Thus, in average 2'R-OTA was approx. half the concentration of OTA but in some cases even exceeded OTA levels. No correlation between the amounts of coffee consumption and OTA or 2'R-OTA levels was observed. CONCLUSION: The results of this study revealed for the first time a high exposure of coffee consumers to 2'R-OTA, a compound formed from OTA during coffee roasting. Since little information is available regarding toxicity and possible carcinogenicity of this compound, further OTA monitoring in blood including 2'R-OTA is advisable.

Contribution of organ vasculature in rat renal analysis for ochratoxin a: relevance to toxicology of nephrotoxins.

Assumptions surrounding the kidney as a target for accumulation of ochratoxin A (OTA) are addressed because the contribution of the toxin in blood seems invariably to have been ignored. Adult rats were maintained for several weeks on toxin-contaminated feed. Using standard perfusion techniques, animals were anaesthetised, a blood sample was taken, one kidney was ligated, and the other kidney perfused with physiological saline in situ under normal blood pressure. Comparative analysis of OTA in pairs of kidneys showed marked reduction in the perfused organ in the range 37%-98% (mean 75%), demonstrating the general efficiency of perfusion supported also by histology, and implying a major role of blood in the total OTA content of kidney. Translation of OTA values in plasma to whole blood, and its predicted contribution as a 25% vascular compartment in kidney gave values similar to those in non-perfused kidneys. Thus, apparent 'accumulation' of OTA in kidney is due to binding to plasma proteins and long half-life in plasma. Attention should be re-focused on whole animal pharmacokinetics during chronic OTA exposure. Similar principles may be applied to DNA-OTA adducts which are now recognised as occurring in blood; application could also extend to other nephrotoxins such as aristolochic acid. Thus, at least, quantitative reassessment in urological tissues seems necessary in attributing adducts specifically as markers of potentially-tumourigenic exposure.

Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models.

The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease in cell viability, but at the same time increased the OTA-DNA adducts formation. These findings indicate the need for an in-depth characterisation of yeast-based products used as mycotoxin-mitigating feed additives, in in vivo models with target animal species taking into account not only their ability to sequester toxins in the gastrointestinal tract but also their potential effects on the biotransformation of mycotoxins.

Biomonitoring of ochratoxin A in blood plasma and exposure assessment of adult students in Bangladesh.

SCOPE: Ochratoxin A (OTA), a mycotoxin known for its nephrotoxic, immunotoxic, and carcinogenic effects in animals, deserves attention due to its widespread occurrence as food and feed contaminant. Studies in many countries report the presence of OTA in human blood plasma or serum at variable levels. However, no biomonitoring study has been carried out in so far, and also food analysis data are insufficient to assess OTA exposure. METHODS AND RESULTS: Therefore, 64 blood samples were collected from healthy university students (32 female, 32 male) in Bangladesh for biomarker analysis. OTA and its metabolite ochratoxin alpha were determined in the plasma samples by a validated method using HPLC-fluorescence analysis. After liquid-liquid extraction, OTA was detected in all plasma samples (100%) at a range of 0.20-6.63 ng/mL and ochratoxin alpha was detected in 95% of the samples at 0.10-0.79 ng/mL. The OTA mean level in plasma of males (0.92 ± 1.09 ng/mL) and females (0.78 ± 1.02) were not significantly different. Statistical analysis of food consumption data for the participants, provided in a food frequency questionnaire, did not reveal a significant association between OTA level in plasma and their intake of typical staple foods (rice, wheat, maize, and lentil). CONCLUSION: The dietary intake of OTA (mean 11.7, max 91.7 ng/kg b.w./wk) calculated on the basis of plasma concentration in Bangladeshi students was lower than the tolerable weekly OTA intake (120 ng/kg b.w./wk) set by EFSA. Nonetheless, further biomonitoring is recommended in cohorts from other parts of the country that may have higher mycotoxin exposure than the present group.

Ochratoxin A kinetics: a review of analytical methods and studies in rat model.

Ochratoxin A (OTA) is a thermostable mycotoxin that contaminates a great variety of foodstuffs. It is nephrotoxic in all of the mammalian species tested, the pig being the most sensitive one; among rodents, rats are the most susceptible to OTA carcinogenicity. Kinetics, by studying the absorption, distribution, metabolism and excretion of xenobiotics, is an important tool in the extrapolation of animal toxicity data for human risk assessment. The most important kinetic studies performed with OTA in rats are reviewed, together with the different methods used for OTA quantification in biological matrices. Twelve studies in Wistar, Sprague-Dawley or F344 rats, using radiolabeled OTA or TLC, HPLC-FLD or LC/MS have been summarized. Very often methods validated for food have been directly applied to tissues. Strain, sex and age differences have been detected but the interpretation is difficult due to the different experimental conditions, and the connection of the several factors that may account for these differences.

Exposure of infants to ochratoxin A with breast milk.

The nephrotoxic and carcinogenic mycotoxin ochratoxin A (OTA) is a worldwide contaminant in food commodities and also found frequently in human biological fluids. Dietary contaminants ingested by nursing mothers can appear in breast milk. But the rate of lactational transfer of OTA has not been investigated so far at various stages of breastfeeding. Therefore, and to investigate OTA exposure of Chilean infants, we conducted a longitudinally designed study in mother-child pairs (n = 21) with parallel collection of maternal blood, milk and of infant urine samples over a period of up to 6 months. Validated analytical methods were applied to determine OTA concentrations in all biological samples (n = 134). OTA was detected in almost all maternal blood plasma, at concentrations ranging between 72 and 639 ng/L. The OTA concentrations in breast milk were on average one quarter of those measured in plasma (M/P ratio 0.25). Interestingly, a higher fraction of circulating OTA was excreted in colostrum (M/P 0.4) than with mature milk (M/P ≤ 0.2). Infants exposure was calculated as daily intake from our new data for OTA levels in breast milk, and taking into account milk consumption and body weight as additional variables: Chilean infants have an average intake of 12.7 ± 9.1 ng/kg bw during the first 6 days after delivery while intake with mature milk results in average values close to 5.0 ng/kg bw/day. Their OTA exposure is discussed in the context of tolerable intake values suggested by different scientific bodies. Moreover, the study design enabled a comparison of OTA intake and infant urine concentrations over the breastfeeding period. The statistical analysis of n = 27 paired values showed a good correlation (r = 0.57) for this type of studies and thereby confirms that urinary OTA analysis in infants is a valid biomarker of exposure.

A comparison of ELISA and HPLC methods for determination of ochratoxin A in human blood serum in the Czech Republic.

Ochratoxin A (OTA) is one of the most naturally occurring fungal toxins in food. It has been detected in high concentrations in serum samples of nephropathic patients and can be applied as one of the markers of potential risk of this disease. Also, OTA can cause adverse effects on human health such as genotoxicity and is anticipated to be a potential human carcinogen. In this study, enzyme-linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC) were applied in analysis of 115 blood serum samples of women in the child rearing age from the Czech Republic and both methods were compared. The OTA was presented in a broad range of concentrations from 0.037 to 1.130 µg/L. The outcome of ELISA and HPLC measurements were well correlated (r=0.907). However, it was observed that ELISA tend to result in underestimating the OTA level at the low serum concentrations. Both methods had the same limits of quantification of 0.050 µg/L under standard operation conditions. When OTA concentration in a sample was too low, the sample was redissolved in only 300 µL of methanol and the detection limit for HPLC was lowered to 0.030 µg OTA/L.

Case report evidence of relationships between hepatocellular carcinoma and ochratoxicosis.

PURPOSE: The incidence of Hepatocellular carcinoma (HCC) is on the rise, but what is causing that trend has remained a mystery. Mycotoxins are almost entirely ignored health problems, and sometimes actually naively belittled in advanced medical care. Ochratoxin A (OTA) is one of the most abundant food contaminating mycotoxins worldwide that is carcinogenic, but no studies have evaluated its levels in HCC patients. Therefore, this study was designed to monitor the presence of OTA in the serum of HCC patients and to quantify the strength of the association between OTA and HCC. METHODS: We conducted a case control-based study on 61 participants. Thirty-nine were HCC cases identified between 2010 and 2012 and individually matched by age, sex, residence and date of recruitment to 22 healthy controls. Serum OTA and alpha-fetoprotein levels were measured by using high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay, respectively. RESULTS: HPLC analysis of 61 serum samples indicated that the highest incidence of elevated OTA was found in the HCC group and was 5-fold higher than in the control group. The concentration of OTA in the HCC group ranged between 0.129 and 10.93 ng/mL with a mean value±SD of 1.1±0.3 ng/mL, while in the normal group it ranged between 0.005 and 0.50 ng/mL with a mean value±SD of 0.201±0.02 ng/mL. The odds ratio for HCC patients presenting OTA levels above the cut-off of 0.207 (calculated by the receiver operating characteristic curve) was 9.78 (95% confidence interval = 2.9095-32.9816, P = 0.0002) with respect to normal controls, suggesting that HCC is 9.8 times as frequent in the exposed group to OTA. CONCLUSION: Our results reveal a strong association between the presence of OTA and HCC, which may offer a coherent explanation for much of the descriptive epidemiology of HCC and suggest new avenues for analytical research.

First evidence of placental transfer of ochratoxin A in horses.

Ochratoxin A (OTA) is a renal mycotoxin and transplacental genotoxic carcinogen. The aim of this study was to evaluate the natural occurrence of OTA in equine blood samples and its placental transfer. For the assessment of OTA levels, serum samples were collected from 12 stallions, 7 cycling mares and 17 pregnant mares. OTA was found in 83% of serum samples (median value = 121.4 pg/mL). For the assessment of placental transfer, serum samples were collected from the 17 mares after delivery and from the umbilical cords of their foals, after foaling. Fourteen serum samples from pregnant mares contained OTA (median value = 106.5 pg/mL), but only 50% of their foals were exposed (median values = 96.6 pg/mL). HPLC analysis carried out on four serum samples (collected from two mares and their respective foals) supported the ELISA results on OTA placental transfer. This is the first report on the natural occurrence of OTA in horse serum samples and placental transfer in horses.

Estimation of ochratoxin A in the human blood of Romanian population.

UNLABELLED: Ochratoxin A (OTA) is a toxic secondary metabolite of fungi belonging to the Aspergillus and Penicillium genera, its presence in human blood being the primary indicator of exposure. AIM: In the present study we determined OTA in 38 blood samples collected from healthy Romanian subjects of both genders. MATERIAL AND METHODS: The OTA was determined through the direct, competitive, solid-phase immunoenzymatic method; the minimum quantification limit for determining OTA in serum samples was 0.0289 ng/mL. RESULTS: The positive sample percentage was 100%. OTA concentrations varied between < 0.04 ng/mL and 1 ng/mL. There were no significant differences between OTA concentrations in men versus women (0.24 +/- 0.20 ng/mL versus 0.17 +/- 0.15 ng/mL, p = 0.3527). CONCLUSIONS: The analyzed blood samples exhibit a very high degree of exposure to OTA, but in only approximately 10% of the subjects exceeded 0.5 ng/mL, considered the threshold for OTA-induced renal pathology.

Analysis of ochratoxin A blood levels in bladder cancer cases and healthy persons from Pakistan.

The mycotoxin ochratoxin A (OTA), a well-known human nephrotoxic and carcinogenic agent, is a public health concern in many countries. Exposure is assessed by means of mycotoxin analysis in food commodities and by human biomonitoring of OTA in blood samples. Data available from several European countries and some studies in Africa, Asia, and the Americas indicate frequent detection of OTA. Thus far, data from developing countries that compare blood levels in healthy and diseased individuals are scarce. Thus, the aim of this investigation was to determine OTA levels in blood samples of bladder cancer patients (n = 96) and healthy controls (n = 31) from Pakistan. OTA in blood plasma was analyzed after extraction by high-performance liquid chromatography (HPLC) with fluorescence detection. Among samples of 87 cancer patients and 30 controls, 92% in total contained quantifiable amounts of OTA. In bladder cancer cases the median OTA concentration was 0.19 ng/ml (mean 0.296; range: 0.03 to 3.41 ng/ml), and in healthy controls the median OTA was 0.19 ng/ml (mean 0.3; range: 0.04 to 1.24 ng/ml). The OTA levels found in the Pakistanian cohorts were comparable to those reported previously for the general population in the European Union. In conclusion, OTA is not likely to play a major role in the etiology of bladder cancer in the Karachi cohort, at least as the sole risk factor.

Plasma ochratoxin A levels, food consumption, and risk biomarkers of a representative sample of men and women from the Molise region in Italy.

BACKGROUND: Ochratoxin A (OTA) is a mycotoxin present in food that can be found in human blood, due to its long half-life. Plasma OTA detection represents a good parameter for evaluating the exposure at the population level. PURPOSE: The relation between plasma OTA levels, dietary habits, and specific disease risk biomarkers (body mass index (BMI), C-reactive protein (CRP), and cardiovascular risk score) was investigated. METHODS: The study involved 327 subjects (150 men and 177 women) aged between 38 and 48 years. Food consumption was evaluated by means of the EPIC questionnaire; plasma OTA was measured by HPLC; CRP was determined in fresh serum samples by a latex particle-enhanced immunoturbidimetric assay. RESULTS: OTA was detected in 99.1% of plasma samples (LOD 25 ng/L); the mean ± SD value was 0.229 ± 0.238 ng/mL. However, only 5.2% of samples exceeded 500 ng/L, considered the threshold for a possible pathogenic activity. The estimated mean daily dietary intake of OTA resulted 0.452 ± 0.468 ng/kg body weight (bw)/day, markedly lower than the tolerable daily intake set by EFSA (17.1 ng/kg bw/day). Processed and mutton/lamb meat were found to contribute most to plasma OTA variance. Nevertheless, cereals, wine, beer, and jam/honey consumption correlated positively with OTA levels. Plasma OTA showed a significant positive association with CRP and cardiovascular risk score (ß = 0.20 ± 0.08; P = 0.015 and ß = 0.25 ± 0.08; P = 0.001, respectively); however, the association was present in men but not in women. CONCLUSIONS: Even if the hypothesis of a possible hepatic toxicity of OTA in humans is yet to be verified, the positive association between plasma OTA and CRP may indicate a possible role of OTA in inflammation status and consequently in the genesis of cardiovascular diseases and cancer.

H NMR spectroscopy-based metabolomic assessment of uremic toxicity, with toxicological outcomes, in male rats following an acute, mid-life insult from ochratoxin a.

Overt response to a single 6.25 mg dose of ochratoxin A (OTA) by oral gavage to 15 months male rats was progressive loss of weight during the following four days. Lost weight was restored within one month and animals had a normal life-span without OTA-related terminal disease. Decline in plasma OTA concentration only commenced four days after dosing, while urinary excretion of OTA and ochratoxin alpha was ongoing. During a temporary period of acute polyuria, a linear relationship between urine output and creatinine concentration persisted. Elimination of other common urinary solutes relative to creatinine was generally maintained during the polyuria phase, except that phosphate excretion increased temporarily. (1)H NMR metabolomic analysis of urine revealed a progressive cyclic shift in the group principal components data cluster from before dosing, throughout the acute insult phase, and returning almost completely to normality when tested six months later. Renal insult by OTA was detected by (1)H NMR within a day of dosing, as the most sensitive early indicator. Notable biomarkers were trimethylamine N-oxide and an aromatic urinary profile dominated by phenylacetylglycine. Tolerance of such a large acute insult by OTA, assessed by rat natural lifetime outcomes, adds a new dimension to toxicology of this xenobiotic.

Presence of ochratoxin A in Tunisian blood nephropathy patients. Exposure level to OTA.

Ochratoxin A (OTA) produced by Aspergillus and Penicillium genera contaminates cereals and different food compounds. OTA presents a wide range of toxic effects, especially nephrotoxicity. It is also considered to be the main causal agent of Balkan Endemic Nephropathy (BEN) which is similar to the Chronic Interstitial Nephropathy with unknown aetiology seen in Tunisia. In this study, we attempted to confirm the relationship between OTA blood levels and the development of renal pathology. Hence, serum OTA levels were measured in several groups of patients having different renal diseases: a group presenting Chronic Interstitial Nephropathy (CIN) with unknown aetiology, a group presenting Chronic Interstitial Nephropathy (CIN) with known aetiology, a group presenting Chronic Glomerular Nephropathy (CGN), and a group presenting Chronic Vascular Nephropathy (CVN). Each group was compared to a healthy control group. In the healthy group, 49% of individuals showed OTA concentrations ranging from 1.7 to 8.5 ng/ml, with a mean value of 3.3±1.5 ng/ml. However, among nephropathic patients, the group with CIN of unknown aetiology showed the highest incidence (76%), ranging from 1.8 to 65 ng/ml with a mean value of 18±7 ng/ml. Even in the healthy group, the calculated Daily Intake (DI) ranged from 5.0 to 24.9 ng/kgb.w./day when compared to the recommended DI by the scientific committee on foods of 5 ng/kgb.w./day, indicating a high degree of exposure to OTA in the Tunisian population. Our study confirms the involvement of this nephrotoxic mycotoxin, present at high blood levels in the Tunisian population, in the outcome of this particular human nephropathy (CIN with unknown aetiology) which is similar to BEN.