Monitoring of human intrauterine aflatoxin exposure

Abstract

The previous studies have shown that afatoxins (AF) can pass through the placenta to the fetus both in experimental animals and in human. These toxins can produce adverse effects including fetal malformations, fetal death, fetal retardation, and tumor formation in F1 generation. The study in Songkhla, Thailand in ]987 indicated that 48% of cord sera samples contained detectable levels of AF. This study was established to monitor intrauterine AF exposure of human fetus whose mothers lived in the are AF contaminated food and AF consumption have been reported to be higher than in Songkhla. The AF were quantified by enzyme-linked immunosorbent assay (ELISA) in 100 neonatal urine samples. The mothers of these subjects lived in Bangkok, Nonthaburi, and Samutprakarn provinces. Urine samples were single voided specimens collected from the neonates within 24 hours after birth. All urine samples were cleaned-up by passing the samples through Sep-Pak C18 cartridges before analyzing with ELISA using polyclonal antibody raised against AFB1. Creatinine concentrations were determined to correct for interindividual variations in volumes voided. Urinary AF levels were detected in the range of 0.69-6.90 ng AFB1 equivalent/mg creatinine with the average level of 2.23 ng AFB1 equivalent/mg creatinine. In order to determine the existence of urinary aflatoxinlike substances (UALS) when using FLISA method, 101 single voided urine samples of healthy infants, who were fed on AF-free diet (only powder milk) and lived in the same area as the neonates, were collected. All urine samples were quantified for urinary AF levels by the same procedures as those employed in the neonates. Some of these urine samples were also verified by HPLC technique. The levels ranging from 0.48 to 19.00 ng AFB1 equivalent nine, with the mean of 5.44 ng AFB1 equivalent/mg creatinine were found by ELISA method. However, the levels of AF were not detected by HPLC technique. These findings indicated that the detectable values shown by ELISA in this study were due to the presence of the interference substances known as UALS. However, the data obtained from HPLC analysis did not suggest significantly high AF exposure in the neonates and infants living in Bangkok and neighboring provinces.