Speciation of arsenic in exfoliated urinary bladder epithelial cells from individuals exposed to arsenic in drinking water.
BACKGROUND
The concentration of arsenic in urine has been used as a marker of exposure to inorganic As (iAs). Relative proportions of urinary metabolites of iAs have been identified as potential biomarkers of susceptibility to iAs toxicity. However, the adverse effects of iAs exposure are ultimately determined by the concentrations of iAs metabolites in target tissues.


OBJECTIVE
In this study we examined the feasibility of analyzing As species in cells that originate in the urinary bladder, a target organ for As-induced cancer in humans.


METHODS
Exfoliated bladder epithelial cells (BECs) were collected from urine of 21 residents of Zimapan, Mexico, who were exposed to iAs in drinking water. We determined concentrations of iAs, methyl-As (MAs), and dimethyl-As (DMAs) in urine using conventional hydride generation-cryotrapping-atomic absorption spectrometry (HG-CT-AAS). We used an optimized HG-CT-AAS technique with detection limits of 12-17 pg As for analysis of As species in BECs.


RESULTS
All urine samples and 20 of 21 BEC samples contained detectable concentrations of iAs, MAs, and DMAs. Sums of concentrations of these As species in BECs ranged from 0.18 to 11.4 ng As/mg protein and in urine from 4.8 to 1,947 ng As/mL. We found no correlations between the concentrations or ratios of As species in BECs and in urine.


CONCLUSIONS
These results suggest that urinary levels of iAs metabolites do not necessarily reflect levels of these metabolites in the bladder epithelium. Thus, analysis of As species in BECs may provide a more effective tool for risk assessment of bladder cancer and other urothelial diseases associated with exposures to iAs.
Hernández-Zavala
Araceli
A
Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Valenzuela
Olga L
OL
Matousek
Tomás
T
Drobná
Zuzana
Z
Dĕdina
Jirí
J
García-Vargas
Gonzalo G
GG
Thomas
David J
DJ
Del Razo
Luz M
LM
Stýblo
Miroslav
M
D000293:Adolescent; D000328:Adult; D001151:Arsenic / Q000145:classification / Q000302:isolation & purification* / Q000633:toxicity; D004847:Epithelial Cells / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013054:Spectrophotometry, Atomic; D001743:Urinary Bladder / Q000737:chemistry* / Q000166:cytology; D014874:Water Pollutants, Chemical / Q000145:classification / Q000302:isolation & purification* / Q000633:toxicity; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D001151:Arsenic