Comparison of chemical-activated luciferase gene expression bioassay and gas chromatography for PCB determination in human serum and follicular fluid.

Abstract

We assessed exposure to dioxin-like compounds using chemical and bioassay analysis in different matrices in a female population. A total of 106 serum and 9 follicular fluid samples were collected from infertile women attending Centers for Reproductive Medicine in Belgium from 1996 to 1998. Major polychlorinated biphenyl (PCB) congeners were quantified by chemical analysis using gas chromatography with electron-capture detection, and the chemical-activated luciferase gene expression (CALUX) bioassay was used to determine the total dioxin-like toxic equivalence (TEQ) of mixtures of polyhalogenated aromatic hydrocarbons present in body fluids, such as serum and follicular fluid. To the best of our knowledge, this is the first investigation to determine TEQ values by the CALUX bioassay in follicular fluid. The TEQ levels in both matrices are well correlated (r = 0.83, p = 0.02). As the chemical and bioassay analysis executed in this study do not cover the same span of polyhalogenated aromatic hydrocarbons, we did not expect totally correlated results. Moreover, the sample workup and quantification of the analytes differed completely. Nonetheless, the TEQ values in human extracts correlated well with the sum of four major PCB congeners chemically determined in both serum and follicular fluid. These results indicate that the CALUX bioassay may serve as a simple, relatively inexpensive prescreening tool for exposure assessment in epidemiologic surveys. Images Figure 1 Figure 2

AH receptor agonist activity in human blood measured with a cell-based bioassay: Evidence for naturally occurring AH receptor ligands in vivo

“…Thus, there is no basis for assigning the approximate 700-fold difference between analytical TEQ and bioassay IEQ observed in this study, to possible synergism. Moreover, it has previously been demonstrated that when assessing purified fractions of PCDD/Fs and PCBs, the TEQ values determined using bioassays similar to the one used in the current study generally agree with those determined using HR-GC/MS analysis (Pauwels et al, 2000;Koppen et al, 2001;Covaci et al, 2002;Warner et al, 2005). It is more likely that the major portion of the activity measured in the reporter gene bioassay of whole blood is from non-PCDD/F or PCB AHR agonists present in the minimally purified extracts.…”

“…More recently, the use of in vitro bioassays based on AHR-regulated genes has increased for estimating HAH concentrations in environmental media, for example, US EPA Method 4425 (Hu et al, 1995;Giesy et al, 1997;Pauwels et al, 2000;US EPA, 2000;Koppen et al, 2001;Covaci et al, 2002;Denison et al, 2004). A commonly used commercially available cell bioassay is the chemical-activated luciferase gene expression (CALUX) bioassay that measures the ability of a chemical mixture to activate AHR-dependent gene expression of the firefly luciferase gene in genetically modified cell lines relative to activation by TCDD (Aarts et al, 1995;Garrison et al, 1996;Murk et al, 1996).…”

Dioxin-Like TEQ of women from the Seveso, Italy area by ID-HRGC/HRMS and CALUX

“…Previous studies using the CALUX s by BDS bioassay all report using 1-4 ml serum (Pauwels et al, 2000;Koppen et al, 2001Koppen et al, , 2002. However, in this study, using 2 ml of plasma per replicate analysis for the CALUX s by XDS bioassay, 31% of samples were not detectable for the PCDD/PCDF fraction and 94% of the samples were not detectable for the PCB fraction.…”

“…The CALUX s by BDS bioassay has been used to estimate serum TEQ in epidemiologic studies of endometriosis (Pauwels et al, 2001), immunologic markers (Van Den Heuvel et al, 2002), and sexual maturation Nawrot et al, 2002). However, limited comparison studies of the CALUX s by BDS bioassay with the chemical analysis measurements have been completed (Pauwels et al, 2000;Koppen et al, 2001). Two studies have been completed comparing the CALUX s by XDS bioassay with HRGC/ HRMS data (Kayama et al, 2001(Kayama et al, , 2002Van Wouwe et al, 2003).…”

“…Two studies have been completed comparing the CALUX s by XDS bioassay with HRGC/ HRMS data (Kayama et al, 2001(Kayama et al, , 2002Van Wouwe et al, 2003). While the results of these individual studies have reported significant correlations between CALUX-TEQ and chemical data (range of r ¼ 0.43-0.57), each study has used a different volume of serum for the CALUX bioassay (ranging from 1 to 10 ml) and variable chemical analysis methods (GC/ECD, GC/MS, HRGC/HRMS), not always measuring all relevant PCDDs, PCDFs, or PCB congeners (Pauwels et al, 2000;Kayama et al, 2001Kayama et al, , 2002Koppen et al, 2001;Van Wouwe et al, 2003). Thus, while there is interest in using the CALUX bioassay as a measure of TEQ in epidemiologic studies, there is still a need to better define the parameters for its use, especially with respect to serum volume needed.…”