Species- and sex-specific renal cytotoxicity of Ochratoxin A and B in vitro

Abstract

SummaryFour different cell models were chosen for comparison of OTA and OTB toxicity: primary porcine (PKC), rat (RPTC) and human renal proximal epithelial cells (HKC) from both sexes and a porcine renal cell line: LLC-PK1. Culture conditions were tested and optimized for each respective cell type (species/sex and origin). All cell types were characterized for epithelial origin and growth patterns and following optimization of dosing strategies and assay procedures, a strict study design was implemented to avoid systemic variations. Due to possible sensitivity differences, three simple endpoints were chosen to provide basic data for interspecies comparison: neutral red uptake, MTT reduction and cell number. Of the endpoints tested neutral red appeared the most sensitive, although all three parameters yielded comparable EC 50 's. Sex-differences were observed between male and female HKC cells following 96 h exposure to OTA, with HKC(m) being more sensitive than HKC(f). No sex-difference was observed in PKC cells, however, the PKC were approximately 3 and 10 times more sensitive than HKC(m) and HKC(f), respectively, to OTA and OTB. Interestingly, the CI 95 of the EC 50 values obtained for OTA (15.5-16.5 µM) and OTB (17.0-21.0 µM) were comparable in the PKC cells. In contrast, OTB had lower cytotoxicity than OTA in HKC and LLC-PK1 (approx. 2-fold) and no effects in RPTC. Overall, HKC(m) were nearly as sensitive as PKC towards OTA, followed by RPTC, LLC-PK1 and HKC(f), thus suggesting a sex specific sensitivity in humans towards OTA induced cytotoxicity.

In vitro investigation of individual and combined cytotoxic effects of ochratoxin A and other selected mycotoxins on renal cells

“…Differences in the specific EC 50 s reported can probably be attributed to the use of different cell lines, different endpoints (e.g., MTT reduction, neutral red uptake, cell counting or LDH release) or indeed to the presence or absence of serum in the culture medium (Bondy and Armstrong, 1998;Dietrich et al, 2001). Interestingly, primary cells have been demonstrated to be more susceptible to the cytotoxic effects of both OTA and OTB when crystal violet staining of intact nuclei is taken as MTT reduction (% control) no effect limit 30% effect limit MTT reduction (% control) no effect limit 30% effect limit MTT reduction (% control) no effect limit endpoint , whereas this was not apparent via assessment of other endpoints .…”

Species- and sex-specific variations in binding of ochratoxin A by renal proteins in vitro

“…Elucidation of the nature and function of this (these) protein(s), with particular reference to the apparent species-differences, could promote a better understanding of the toxicity of OTA and hence provide a sound basis for risk extrapolation. Due to the observed sex-and species-differerences in OTA toxicity both in vivo and in vitro DIETRICH et al 2001;O'BRIEN et al 2001), the first logical step was to investigate the effects of steroids on OTA binding to renal proteins. None of the substances tested in the current study (testosterone, estradiol and aldosterone) Another candidate function of this (these) binding component(s), which could account for the species-differences observed both in vivo and in vitro, is organic anion transport.…”

In vitro evaluation of human xenobiotic toxicity: Scientific concepts and the novel integrated discrete multiple cell coculture (IdMOC) technology

“…Besides hepatocytes, primary cells cultured from various organs such as kidney (Dietrich et al, 2001;Li et al, 2006;Lock et al, 2007), nervous system (Stair et al, 2005;Guizzetti et al, 2005), heart (Hasinoff et al, 2007), skeletal muscle (Mazno et al, 2003), vascular endothelium (Harlan et al, 1983;Kim et al, 2007), lung (Li, 1986;Li and Myers, 1988;Bakand et al, 2007;Han et al, 2007;Sayes et al, 2007), and blood/bone marrow cells (Deldar and Stevens, 1993;Rich and Hall, 2005) have also been applied towards the evaluation of xenobiotic toxicity. The various primary cell systems used may be representative of the appropriate in vivo target cells for their respective organs.…”