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.     

Expression of Hsp70 in kidney cells exposed to ochratoxin A

Ochratoxin A (OTA) is a possible etiological agent of endemic nephropathy, a chronic renal disease with high prevalence in limited geographic areas. Ochratoxicosis has many characteristics of different pathological states in which heat shock proteins (Hsps) are usually induced. The most inducible heat shock proteins belong to the Hsp70 family. We determined the level of expression of Hsp70 by the Western blot analysis in kidneys of rats treated with low doses of OTA and in LLC-PK1 and MDCK cells exposed to OTA. Estimation of cell viability and release of lactate dehydrogenase (LDH) confirmed the toxic effects of OTA on cultured cells. OTA affects the relative distribution of two Hsp70 isoforms (68-kDa and 74-kDa isoforms), but does not change total amount of Hsp70 in rat kidney. No changes in the Hsp70 level were detected in LLC-PK1 and MDCK cells treated with OTA, although the cells were seriously injured, as was seen from the reduced cell viability and increased release of LDH. Both cell lines were capable of having Hsp70 induced following a heat shock. However, exposure of the cells to OTA before the heat shock challenge prevented Hsp70 induction. Results of the study show that OTA does not induce Hsp70 in rat kidney or in cultured kidney cells. The absence of Hsp70 protective effects in the cells and tissues might be a possible explanation for the cumulative destructive effects of OTA and a silent onset of endemic nephropathy in humans and of OTA-induced experimental nephrotoxicity in animals.     

Ochratoxin and Kidney Disease in the Human

Abstract

Ochratoxin A (OTA), produced by several species of Aspergillus and Penicillium, is known for its nephrotoxicity in pigs and rats. Human exposure to this toxin, essentially by consumption of contaminated food and drinks derived from cereals, could be potentially nephrotoxic. There is a paradox between the risk of OTA for human renal disease, due to the wide distribution of this mycotoxin throughout the world, and the rarity of reported cases demonstrating its role in chronic renal disease. Possible OTA-induced acute renal failure was recently reported in Italy after a farmer and his wife worked 8 hours in a granary closed for several months. Renal biopsy in the woman who developed nonoliguric acute renal failure revealed lesions of acute tubular necrosis. A strain of Aspergillus ochraceus producing OTA was isolated from the wheat. Chronic nephrotoxicity due to OTA is probably more usual and makes the diagnosis more difficult. Balkan Endemic Nephropathy, a chronic tubulo-interstitial renal disease, could be due to OTA. Epidemiologic studies showed that in areas where high OTA levels are reached in food and in the blood of the population, there is a high incidence of nephropathy and renal tumours. The demonstration of DNA adducts in kidneys of animals exposed to OTA and similar adducts in renal tissue and tumours from individuals in the endemic region of the Balkan countries highlights a new molecular epidemiological approach. Karyomegalic interstitial nephritis, characterized by karyomegaly in proximal and distal tubular epithelial cells, has been reported in nine patients. Karyomegaly could be due to an environmental toxin that interferes with DNA replication. Involvement of the oxidative pathway in genotoxicity of OTA is known and oxidant stress induces DNA damage. Therefore, karyomegaly could be a histological marker of interstitial nephritis due to OTA. In developing countries where the prevalence of end stage renal failure due to nephropathy of uncertain etiology is high. OTA and probably other mycotoxins could be major environmental factors in the occurrence of renal disease.     

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 μg/kg and 0.1–2.3 ng/ml, respectively, in controls and healthy individuals and 0.3–46 830 μg/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.     

Apoptosis and oxidative stress induced by ochratoxin A in rat kidney

Ochratoxin A (OTA) is a widespread mycotoxin produced by several species of fungi. OTA induces a tubular-interstitial nephropathy in humans and in animals. It has been implicated as one of the aetiological agents involved in the development of endemic nephropathy. OTA-induced oxidative stress and apoptosis may play key roles in the development of chronic tubulointerstitial nephritis connected to the long-term exposure to this food contaminant. We studied the effects of low doses of OTA on kidney cells. Wistar rats were treated with 120 g OTA/kg bodyweight daily, for 10, 30 or 60 days. Toxin concentration in kidney was proportional to the time of exposure, and amounted to 547.2, 752.5 and 930.3 ng OTA/g kidney tissue after 10, 30 and 60 days, respectively. OTA treatment caused an increased number of cells undergoing apoptosis in both proximal and distal epithelial kidney cells. The apoptotic cells were visualised using the TUNEL assay and staining with haematoxylin and eosin in situ. The number of apoptotic cells in rats treated for 10, 30 and 60 days increased by 5-, 6.4- and 12.7-fold, respectively, compared with the control cells. However, DNA electrophoresis did not show characteristic fragmentation (DNA laddering). The oxidative stress was evident via increased malondialdehyde formation. The concentration of lipid peroxides showed an increase (36%), but the activity of superoxide dismutase decreased (26%) in 60-day treated rats. In spite of the observed biochemical and morphological changes in the kidney cells, renal functional status was preserved to the end of experiment. This study demonstrates that a combination of morphologic and biochemical markers can be used to monitor early cell death in OTA-induced renal injury. We have shown that the exposure to the relatively low OTA concentrations has activated apoptotic processes and oxidative damage in kidney cells.     

Ochratoxin A: In Utero Exposure in Mice Induces Adducts in Testicular DNA

Ochratoxin A (OTA) is a nephrotoxin and carcinogen that is associated with Balkan endemic nephropathy and urinary tract tumors. OTA crosses the placenta and causes adducts in the liver and kidney DNA of newborns. Because the testis and kidney develop from the same embryonic tissue, we reasoned that OTA also may cause adducts transplacentally in the testis. We tested the hypothesis that acute exposure to OTA, via food and via exposure in utero, causes adducts in testicular DNA and that these lesions are identical to those that can be produced in the kidney and testis by the consumption of OTA. Adult mice received a single dose of OTA (from 0–1,056 µg/kg) by gavage. Pregnant mice received a single i.p. injection of OTA (2.5 mg/kg) at gestation day 17. DNA adducts were determined by ³²P-postlabeling. Gavage-fed animals sacrificed after 48 hours accumulated OTA in kidney and testis and showed DNA adducts in kidney and testis. Some OTA metabolites isolated from the tissues were similar in both organs (kidney and testis). The litters of mice exposed prenatally to OTA showed no signs of overt toxicity. However, newborn and 1-month old males had DNA adducts in kidney and testis that were chromatographically similar to DNA adducts observed in the kidney and testis of gavage-fed adults. One adduct was identified previously as C8-dG-OTA adduct by LC MS/MS. No adducts were observed in males from dams not exposed to OTA. Our findings that in utero exposure to OTA causes adducts in the testicular DNA of male offspring support a possible role for OTA in testicular cancer.     

Evidence for covalent DNA adduction by ochratoxin A following chronic exposure to rat and subacute exposure to pig

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is a potent renal carcinogen in male rats and is suspected of being the etiological agent of Balkan endemic nephropathy (BEN) and its associated urinary tract cancers. Conflicting results have been obtained regarding the genotoxicity of OTA and its ability to react directly with DNA upon oxidative bioactivation to yield covalent DNA adducts. To characterize DNA adduction by OTA, the present study utilizes the photooxidative properties of the toxin to generate authentic C8 OTA-3'-monophosphate-deoxyguanosine (3'-dGMP) adducts for use as cochromatographic standards for (32)P-postlabeling detection of OTA-mediated DNA adduction in the kidney of rat and pig. Our results show evidence for the photooxidation of OTA to yield carbon (C)- and oxygen (O)-bonded C8-3'-dGMP adducts (C-C8 and O-C8) that have been isolated and characterized by LC/MS with in-line UV and electrospray negative ionization (ES(-)) detection. A comparison to previously published work on related C8-dG adducts supports C8 attachment by OTA. The C-C8 OTA-3'-dGMP adduct standard is shown by (32)P-postlabeling to comigrate with the major lesion detected in the kidney of rat following chronic exposure to OTA and with one of four adducts detected in the kidney of pig following subacute exposure to the toxin. The O-C8 OTA-3'-dGMP adduct standard is also shown to coelute with a lesion detected in rat kidney. These findings suggest a role for the OTA phenoxyl radical in OTA-mediated DNA adduction in vivo, provide a rationale for the tumorigenesis of OTA, and strengthen the OTA hypothesis in the etiology of BEN and the associated urinary tract tumors.     

Molecular Aspects of Human Ochratoxicosis in Tunisia

Ochratoxin A (OTA) has been found in Tunisia since 1983 in foodstuffs and human blood pnmanly from rural areas A nephropathy sirmlar to Balkan Endemic Nephropathy (BEN) has been found in Tunisian populations especially in nephropathic patients having CrrA in blood due to chronic exposure by ingestion of contaminated food Some of them have shown several karyomegalic tubular cells in their renal biopsy

We designed investigations to produce in rat experimental nephropathy using OTA. These studies showed karyomegalic cells with alteration of renal tubular tissue combined with megacytosis. These observations suggested that the karyomegaly and megacytosis are induced by OTA in rats and could be also in humans. In addition, abnormal mitosis are observed at the early stage of the pathology (30 days of treatment), suggesting that renal tubular cells can regenerate if exposure to OTA is limited to a short period. After 90 days of treatment the lesions became irreversible. The karyomegaly was worst. Apoptotic cells appeared, but abnormal mitosis were no longer observed.     

Age-related differences in the toxicity of ochratoxin A in female rats.

Ochratoxin A (OTA) is a mycotoxin found in food and feedstuffs of plant and animal origin. OTA exposure is related to nephropathy in humans. Age-related differences, especially in nephro- and immunotoxicity of OTA, were investigated in young adult (aged 12 weeks) and old (aged 27-30 months) female SPF Wag rats, treated by gavage with 0, 0.07, 0.34 or 1.68 mg OTA/kg body weight for 4 weeks. In both age groups, survival was significantly decreased in the highest dose group. Clinical condition, body weight, clinical chemistry parameters (ALAT, ASAT, creatinin and urea) and target organs (as identified by weight and pathology - kidney, liver, adrenals, forestomach and brain) were affected by age and dose, but often more severely in old than in young rats. OTA induced primarily nephropathy. Old rats were more sensitive to induction of tubular karyomegaly and vacuolation/necrosis. In young rats, OTA induced a dose-related thickening of the basement membrane and reduction in splenic T-cell fraction. Decreased IgG levels were seen at 0.34 mg/kg OTA (young and old rats) and 1.68 mg/kg OTA (young rats). Vacuolation of the white brain matter (cerebellar medulla and ventral parts of the brain stem) was significantly increased in young rats at 0.34 and 1.68 mg/kg OTA and in old rats at 0.07 and 0.34 mg/kg OTA. It was concluded that: (1) the profiles of OTA toxicity for both age groups are similar, with the kidney and possibly the brain being primary target organs; (2) based on clinical and pathological data old rats are more sensitive to OTA than young rats; and (3) the immune system is probably not the primary target of OTA toxicity.     

Rat Tumour Histopathology Associated with Experimental Chronic Dietary Exposure to Ochratoxin A in Prediction of the Mycotoxin’s Risk for Human Cancers

Mammalian animal toxicity of ochratoxin A (OTA) has focused largely in the past half-century on pigs because of initial recognition of it as a principal cause of intermittent growth suppression and renal disease caused by mouldy feed. Subsequent classical toxicology has used laboratory rodents because renal pathology in pigs raised questions concerning possible involvement in the human idiopathic bilateral renal atrophy of Balkan endemic nephropathy for which OTA was a focus of attention for human nephropathy through 1980s and into 2000s. Emphasis on human nephropathy has more recently concerned the plant metabolite aristolochic acid. Recognition that agricultural management can often minimise food and feed-stuff spoilage by OTA-producing Aspergilli and Penicillia has moderated some of the risks for animals. Legislation for human food safety combined with sophisticated analysis generally provides safety in the developed world. Chronic experimental exposure of male rats, in the absence of clinical dis-ease, specifically causes renal cancer. The possibility of this as a unique model for the human has generated considerable experimental evidence which may be more directly relevant for carcinogenesis in the complex kidney than that obtained from biochemical toxicities in vitro. Nevertheless, there does not appear to be any case of human renal or urinary tract cancer for which there is verified etiological proof for causation by OTA, contrary to much claim in the literature. To contribute to such debate, histopathology review of OTA/rat renal cancers, augmented where appropriate by immune profiles, has been completed for all remaining tumours in our research archive. Overall consistency of positivity for vimentin, is matched with occasional positives either for CD10 or the cytokeratin MNF 116. The current situation is discussed. Suggestion that OTA could cause human testicular cancer has also been challenged as unsupported by any experimental findings in rats, where the Leydig cell tumour immune profile does not match that of human germ cell neoplasms.     

Protection by indomethacin and aspirin against genotoxicity of ochratoxin A,particularly in the urinary bladder and kidney

Ochratoxin A (OTA) is a ubiquitous nephrotoxic mycotoxin which was shown to be carcinogenic to laboratory animals and may be responsible for kidney pelvis, ureter and urinary bladder tumors associated with Balkan endemic nephropathy in man. Previous evidence from this laboratory demonstrated that OTA exposure results in adduct formation on kidney, testicles, liver and spleen DNA. We show in this study that after a single oral administration of OTA to mice (2 mg/kg body weight) a high level of DNA adducts (150 per 10⁹ nucleotides) is also detected in the urinary bladder. The metabolic pathway of OTA leading to genotoxic compounds is not yet known. We demonstrate here that two inhibitors of the prostaglandin H synthase, indomethacin and aspirin, administered to mice before OTA treatment, dramatically reduce the amounts of DNA adducts, particularly in the urinary bladder and kidney. This suggests a role of protaglandin H synthase in the metabolism of OTA leading to active metabolites which react with DNA.     

Ochratoxin A and beta2-microglobulinuria in healthy individuals and in chronic interstitial nephropathy patients in the centre of Tunisia: a hot spot of Ochratoxin A exposure

Ochratoxin A (OTA) is a nephrotoxic mycotoxin considered to be the causal agent of the Balkan endemic nephropathy (BEN). In Tunisia, a chronic interstitial nephropathy (CIN) of unknown aetiology, resembling BEN, has been characterised wherein OTA seems to be implicated too. However, despite the considerable number of investigations conducted so far, the role of OTA in the outcome of this human nephropathy is still uncertain. In this study, an attempt is being made to consolidate the link between OTA and the Tunisian CIN of unknown aetiology. Blood OTA and beta(2)-microglobulinuria levels were measured in several groups of healthy individuals and patients having different renal diseases of known and unknown aetiologies (100 nephropathy patients and 40 healthy subjects). The high blood OTA and beta(2)-microglobulinuria levels seem to be strongly associated to the CIN of unknown aetiology. Our results support the involvement of this nephrotoxic agent in the outcome of this particular human nephropathy and underline furthermore the importance of beta(2)-microglobulinuria in the characterization of this disease.     

Deleterious Effects of Mycotoxin Combinations Involving Ochratoxin A

Ochratoxin A (OTA) is a nephrotoxic mycotoxin with carcinogenic properties. Its presence was detected in various foodstuffs all over the world but with significantly higher frequency and concentrations in areas with endemic nephropathy (EN). Even though food is often contaminated with more than one mycotoxin, earlier studies focused on the occurrence and toxicology of only OTA. Only a limited number of surveys showed that OTA co-occurs in food with mycotoxins (citrinin-CIT, penicilic acid, fumonisin B₁-FB₁, aflatoxins-AF) which exert nephrotoxic, carcinogenic or carcinogen-promoting activity. This review summarises the findings on OTA and its co-occurrence with the mentioned mycotoxins in food as well as experimental data on their combined toxicity. Most of the tested mycotoxin mixtures involving OTA produced additive or synergistic effects in experimental models suggesting that these combinations represent a significant health hazard. Special attention should be given to mixtures that include carcinogenic and cancer-promoting mycotoxins.     

Detection of ochratoxin A-induced DNA damage in MDCK cells by alkaline single cell gel electrophoresis (comet assay)

The mycotoxin ochratoxin A (OTA), a widespread contaminant of food and feedstuffs, is nephrotoxic, immunosuppressive and carcinogenic in domestic and laboratory animals. Additionally, it is suspected as being responsible for urinary tract tumours in patients suffering from Balkan endemic nephropathy. Moreover, evidence has accumulated that OTA is a genotoxic carcinogen, although the mechanism that results in DNA damage has not been fully resolved. In this study, the induction of DNA damage by OTA and the subsequent DNA repair was investigated by alkaline single cell gel electrophoresis (comet assay) in cells originally derived from the kidney, a target organ of OTA. With modifications of the method, the influence of OTA uptake into the cells and of DNA repair on the genotoxic effect of OTA should be investigated. In Madin-Darby canine kidney (MDCK) cells, OTA induced single-strand breaks in a concentration dependent manner. When an external metabolising enzyme system (S9-mix from rat liver) was added, this genotoxic effect was significantly stronger. By co-incubation with methotrexate or with the mycotoxin citrinin, a substrate of the organic anion transporter, the adverse effect of OTA was inhibited. When DNA repair was inhibited by addition of cytosine arabinoside and hydroxyurea, the tail length increased dramatically and all treated cells showed single-strand breaks. A further culture of the damaged cells in the absence of any supplement resulted in a complete repair of the DNA damage within 2 h. Adverse effects on the mechanisms of DNA repair, or exposure to OTA in periods of reduced DNA repair capacity may influence the genotoxic potency of OTA and have to be regarded as a further mechanism by which genotoxic effects of OTA can be performed.     

Ochratoxin A and Kidney Oxidative Stress: The Role of Nutraceuticals in Veterinary Medicine—A Review

The problem of residues of toxic contaminants in food products has assumed considerable importance in terms of food safety. Naturally occurring contaminants, such as mycotoxins, are monitored routinely in the agricultural and food industries. Unfortunately, the consequences of the presence of mycotoxins in foodstuffs are evident in livestock farms, where both subacute and chronic effects on animal health are observed and could have non-negligible effects on human health. Ochratoxin A (OTA) is a common mycotoxin that contaminates food and feeds. Due to its thermal stability, the eradication of OTA from the food chain is very difficult. Consequently, humans and animals are frequently exposed to OTA in daily life. In this review article, we will devote time to highlighting the redox-based nephrotoxicity that occurs during OTA intoxication. In the past few decades, the literature has improved on the main molecules and enzymes involved in the redox signaling pathway as well as on some new antioxidant compounds as therapeutic strategies to counteract oxidative stress. The knowledge shown in this work will address the use of nutraceutical substances as dietary supplements, which would in turn improve the prophylactic and pharmacological treatment of redox-associated kidney diseases during OTA exposure, and will attempt to promote animal feed supplementation.     

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.     

Ochratoxin A in human sera in the area with endemic nephropathy in Croatia

Ochratoxin A (OA) is nephrotoxic fungal metabolite (mycotoxin) occurring in foodstuffs. The compound is causally associated with mycotoxin porcine nephropathy, a disease comparable with a human kidney disease called endemic nephropathy (EN). In this paper we presented results obtained over a 10-year period in the hyperendemic village Kaniža, and in control villages where no clinical cases of nephropathy had been found. In the hyperendemic village Kaniža and non-endemic villages the incidence of OA in human blood was up to 4.5% (range 2–50 ng/ml) and up to 2.4% (range 2–10 ng/ml), respectively. Almost all samples of food and feed, collected randomly in the hyperendemic village were found to contain OA. Considering marked exposure to OA in Kaniža, it was assumed that incidence of EN in this population could be related to OA contamination of food and feed. Ireland Ltd.     

Karyomegaly of tubular kidney cells in human chronic interstitial nephropathy in Tunisia: respective role of Ochratoxin A and possible genetic predisposition

Karyomegalic nephropathy associated to bizarre enlargement of nuclei in renal tubular epithelial cells was first described by Mihatch in 1979. We present herein additional cases occurring in three siblings suffering from chronic interstitial nephropathy (CIN) of unknown aetiology where the renal biopsies showed numerous enlarged and hyperchromatic nuclei. CIN of unknown aetiology has been previously characterized and showed striking similarities with Balkan Endemic Nephropathy (BEN). Ochratoxin A (OTA) is a nephrotoxic mycotoxin suspected to be the causal agent of the BEN as well as the Tunisian CIN of unknown aetiology. OTA is incriminated in the onset of these disclosed cases of karyomegalic nephropathy since high OTA concentrations were found in blood (505.83 ng/ml, 102.63 ng/ml and 1023 ng/ml) and in urine (94.40 ng/ml and 10.18 ng/ml) of two of them. Moreover, we have investigated OTA in blood and urine as well as in food samples of the entire household (21 people). Our findings suggest (i) a link between OTA and the outcome of this karyomegalic nephropathy, and (ii) the possible involvement of a genetic factor since the three cases have the same haplotype B27/35.     

Ochratoxin A and β2-microglobulin in BEN patients and controls

Ochratoxin A (OTA) is a mycotoxin naturally occurring in different foods. OTA is arguably a risk factor for Balkan endemic nephropathy (BEN). The aims of this study are to (1) test the OTA-BEN association in BEN-groups and controls and (2) determine whether urine β2-microglobulin, a marker of impaired ability of the kidneys to re-absorb, is related to OTA. BEN patients had significantly higher OTA serum levels. Within the offspring, OTA was significantly related to higher β2-microglobulin excretion. OTA (2005/2006) was related to a higher incidence of BEN after 2008, providing further evidence that OTA is a risk factor for BEN.     

Ochratoxin A and its metabolite ochratoxin alpha in urine and assessment of the exposure of inhabitants of Lleida, Spain

Ochratoxin A (OTA) as well as its metabolite ochratoxin α (OTα) were detected in human urine in order to assess the exposure to OTA of a group of 72 adult inhabitants of the city of Lleida (Spain). Urine samples were enzymatically treated; OTA and OTα were separated by liquid-liquid extraction, and detected by HPLC-fluorescence. Exposure to OTA was also evaluated by the estimation of its daily intake from food contamination data from the literature and from food consumption data provided by the participants, who filled in a food frequency questionnaire (FFQ) and a three-day food consumption record (3DR). OTA occurrence (12.5%, limit of detection = 0.034 ng/mL) was lower than OTα occurrence (61.1%, limit of detection = 0.023 ng/mL). The range of concentrations was 0.057-0.562 ng/mL and 0.056-2.894 ng/mL for OTA and for OTα, respectively. It could be observed for positive samples that the FFQ data were related to the OTA concentration in urine, whereas the 3DR data were related to the OTα levels in urine. The OTA estimated daily intake of the participants was lower than 30% of the latest provisional tolerable daily intake of 14 ng/kg body weight/day in the worst cases of exposure.