Synergistic Interaction of Ochratoxin A and Acrylamide Toxins in Human Kidney and Liver Cells.

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium, and it is found in many foods. Acrylamide (AA) can be produced in foods treated at high temperatures. In this study, we investigated the combined toxicity of OTA and AA against human renal and hepatic cells in vitro. The concentration at which the synergistic effect of OTA and AA occurs was determined using the combination index obtained from the cell viability results for OTA and AA individually or in combination. The synergistic toxicity of both substances was evaluated by cell viability and the production of reactive oxygen species. In addition, apoptosis-related markers were significantly upregulated by OTA and AA individually or in combination. To determine the combined toxic effects of OTA and AA on the cells, the levels of enzymes involved in the phase I reaction and apoptosis-related markers were determined using quantitative (q)PCR and Western blot. The expression levels of CYP enzymes CYP1A1 and CYP1A2 involved in the phase I reaction significantly increased when the cells were treated with OTA and AA in combination. The expression of apoptosis-related markers, Bcl2-associated X protein (Bax) and caspase 3, also increased when the cells were treated with OTA and AA in combination. Therefore, the synergistic toxicity of OTA and AA suggests that such effects may contribute to nephrotoxicity and hepatotoxicity.

Ochratoxin A-Induced Hepatotoxicity through Phase I and Phase II Reactions Regulated by AhR in Liver Cells.

Ochratoxin A (OTA) is a widespread mycotoxin produced by several species of the genera Aspergillus and Penicillium. OTA exists in a variety of foods, including rice, oats, and coffee and is hepatotoxic, with a similar mode of action as aflatoxin B1. The precise mechanism of cytotoxicity is not yet known, but oxidative damage is suspected to contribute to its cytotoxic effects. In this study, human hepatocyte HepG2 cells were treated with various concentrations of OTA (5-500 nM) for 48 h. OTA triggered oxidative stress as demonstrated by glutathione depletion and increased reactive oxygen species, malondialdehyde level, and nitric oxide production. Apoptosis was observed with 500 nM OTA treatment. OTA increased both the mRNA and protein expression of phase I and II enzymes. The same results were observed in an in vivo study using ICR mice. Furthermore, the relationship between phase I and II enzymes was demonstrated by the knockdown of the aryl hydrocarbon receptor (AhR) and NF-E2-related factor 2 (Nrf2) with siRNA. Taken together, our results show that OTA induces oxidative stress through the phase I reaction regulated by AhR and induces apoptosis, and that the phase II reaction is activated by Nrf2 in the presence of oxidative stress.

Renal toxicity through AhR, PXR, and Nrf2 signaling pathway activation of ochratoxin A-induced oxidative stress in kidney cells.

Because ochratoxin A (OTA) is widely found in foods, people are susceptible to OTA exposure. The mechanism leading to renal toxicity induced by OTA remains unclear. The aim of this study was to investigate OTA-induced toxicity in human proximal tubule HK-2 cells. OTA decreased cell viability, and the expression of kidney injury molecule-1 (KIM-1), a kidney damage marker, was increased when HK-2 cells were exposed to OTA. Additionally, OTA treatment of cells increased intracellular reactive oxygen species and malondialdehyde and decreased glutathione levels. OTA-treated cells induced the aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) genes followed by induction of the cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP3A4 genes representing phase I enzyme. The mRNA expression of phase II enzymes such as heme oxygenase-1, nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1, and glutamate cysteine ligase catalytic subunit were upregulated by activation of NF-E2-related factor 2 (Nrf2) translocation by treatment with OTA. The response of OTA-orally administered mice also showed marked increases in these enzymes as well as KIM-1. These results indicate that OTA induces phase I and II enzymes through the AhR, PXR, and Nrf2 signaling pathways in HK-2 cells, which may lead to modulation of proximal tubule injury.

Cell-SELEX-Based Identification of a Human and Mouse Cross-Reactive Endothelial Cell-Internalizing Aptamer.

Increased interest and insights gained by researchers on the roles of endothelial cells in the pathophysiology of cancer, inflammatory, and cardiovascular diseases have led to the design of pharmacological interventions aimed at the endothelium lining in the diseased sites. Toward this end, we used established brain microvascular endothelial cell lines mouse (bEND3), human (hCMEC/D3), and Toggle Cell-SELEX to identify a species cross-reactive, endothelial cell-internalizing aptamer R11-3. This 2'F-modified RNA aptamer is specific for endothelial cells as no internalization was seen with cells of nonendothelial origin. R11-3 was truncated in size, and its potential in endothelial targeted therapeutics was established using VEGFR2 targeting long interfering RNA (liRNA) aptamer chimera. Due to its specificity for both mouse and human endothelial cells, we believe that this aptamer not only fits for development of endothelial targeted drug development for human diseases but is also suitable for preclinical evaluation in mice.

CT Quantification of Lungs and Airways in Normal Korean Subjects.

OBJECTIVE: To measure and compare the quantitative parameters of the lungs and airways in Korean never-smokers and current or former smokers ("ever-smokers"). MATERIALS AND METHODS: Never-smokers (n = 119) and ever-smokers (n = 45) who had normal spirometry and visually normal chest computed tomography (CT) results were retrospectively enrolled in this study. For quantitative CT analyses, the low attenuation area (LAA) of LAAI-950, LAAE-856, CT attenuation value at the 15th percentile, mean lung attenuation (MLA), bronchial wall thickness of inner perimeter of a 10 mm diameter airway (Pi10), total lung capacity (TLCCT), and functional residual capacity (FRCCT) were calculated based on inspiratory and expiratory CT images. To compare the results between groups according to age, sex, and smoking history, independent t test, one way ANOVA, correlation test, and simple and multiple regression analyses were performed. RESULTS: The values of attenuation parameters and volume on inspiratory and expiratory quantitative computed tomography (QCT) were significantly different between males and females (p < 0.001). The MLA and the 15th percentile value on inspiratory QCT were significantly lower in the ever-smoker group than in the never-smoker group (p < 0.05). On expiratory QCT, all lung attenuation parameters were significantly different according to the age range (p < 0.05). Pi10 in ever-smokers was significantly correlated with forced expiratory volume in 1 second/forced vital capacity (r = -0.455, p = 0.003). In simple and multivariate regression analyses, TLCCT, FRCCT, and age showed significant associations with lung attenuation (p < 0.05), and only TLCCT was significantly associated with inspiratory Pi10. CONCLUSION: In Korean subjects with normal spirometry and visually normal chest CT, there may be significant differences in QCT parameters according to sex, age, and smoking history.

Anti-inflammatory effect of sugar-amino acid Maillard reaction products on intestinal inflammation model in vitro and in vivo.

The Maillard reaction is a nonenzymatic reaction between an amino acid and a reducing sugar that usually occurs upon heating. This reaction occurs routinely in cooking, generates numerous products, which are collectively referred to as Maillard reaction products (MRPs) contributing to aroma and color features. Advanced glycation end-products (AGEs) transformed from MRPs are participated in many types of inflammation reaction. In this study, various sugar-amino acid MRPs were prepared from three different amino acids (lysine, arginine, and glycine) and sugars (glucose, fructose, and galactose) for 1 h with heating at 121 °C. Treatment of lipopolysaccharide-stimulated RAW264.7 macrophages with the MRPs decreased nitric oxide (NO) expression compared to control without MRPs treatment. MRPs derived from lysine and galactose (Lys-Gal MRPs) significantly inhibited NO expression. The retentate fraction of Lys-Gal MRPs with cut-off of molecular weight of 3-10 kDa (LGCM) suppressed NO expression more effectively than did Lys-Gal MRPs. The anti-inflammatory effect of LGCM was evaluated using a co-culture system consisting of Caco-2 (apical side) and RAW264.7 or THP-1 (basolateral side) cells to investigate the gut inflammation reaction by stimulated macrophage cells. In this system, LGCM prevented a decreased transepithelial electrical resistance, and decreased both tumor necrosis factor-α production in macrophages and interleukin (IL)-8 and IL-1ß mRNA expression in Caco-2 cells. In co-culture and in vivo dextran sulfate sodium (DSS)-induced colitis model study, we also observed the anti-inflammatory activity of LGCM.

Diffuse Infiltrative Splenic Lymphoma: Diagnostic Efficacy of Arterial-Phase CT.

OBJECTIVE: To evaluate the diagnostic performance of obliteration of normal heterogeneous enhancement of the spleen (ONHES) on arterial phase (AP) computed tomography (CT) images in diffuse infiltrative splenic lymphoma (DISL). MATERIALS AND METHODS: One hundred and thirty-six patients with lymphoma who had undergone two-phase (arterial and portal venous) abdominal CT were included in this study. We retrospectively evaluated the diagnostic performance of ONHES on AP CT in diagnosing DISL. Two observers evaluated ONHES on AP CT using the 5-point confidence level and assessed the presence or absence of subjective splenomegaly on axial CT images. Another two observers measured the splenic index as proposed by objective CT criteria. Statistical analysis included interobserver agreement and diagnostic performance of CT findings. RESULTS: Eleven of the 136 patients with lymphoma had DISL. The area under the receiver operating characteristic curve of ONHES (0.948 for observer 1 and 0.922 for observer 2) was superior to that of the splenic index (0.872 for observer 3 and 0.877 for observer 4), but the difference was not statistically significant (p > 0.05). The diagnostic performance of ONHES in conjunction with subjective splenomegaly showed higher diagnostic performance, as compared with subjective splenomegaly alone (accuracy: 100% and 85.3% for observer 1, 98.5% and 87.5% for observer 2; positive predictive value: 100% and 35.5% for observer 1, 90.9% and 39.3% for observer 2, respectively). CONCLUSION: Obliteration of normal heterogeneous enhancement of the spleen in conjunction with subjective splenomegaly can improve the diagnostic performance for DISL. Our results suggest that ONHES on AP CT images could be useful as an adjunctive diagnostic indicator of DISL in patients with lymphoma.