Validation of Urinary Sphingolipid Metabolites as Biomarker of Effect for Fumonisins Exposure in Kenyan Children.

CONTEXT: Fumonisins [FNs], a group of mycotoxins produced mainly by Fusarium species, are ubiquitous food contaminants, especially for maize. Fumonisin B1 [FB1 ] caused severe toxicities in farm animals, induced kidney and liver tumors in rodents and is associated with many human adverse health effects, including esophageal cancer. International Agency for Research on Cancer [IARC] categorizes FB1 as possible human carcinogen [Group 2B]. Inhibition of ceramide synthesis and disruption of sphingolipids metabolism are well studied as the major mechanisms of FB1 -induced toxicity. Increases in sphinganine [Sa] and decrease in sphingosine [So] levels and their ratio are validated biomarkers of FB1 effects.

METHODS: In this study we measured urinary levels of Sa, So and Sa/So in 284 children age 1 to 14 years who consume maize as a staple diet. Exfoliated cells from urine were processed and sphingolipids quantified by High Pressure Liquid Chromatography.

RESULTS AND CONCLUSIONS: Sa and So were detectable in 95.07% and 98.94% of samples respectively. Creatinine adjusted mean levels and standard deviation of Sa, So, and Sa/So ratio were 1.23 ± 2.18, 4.99 ± 8.3, and 0.296 ± 0.587 nM. These results further confirmed findings in studies with human adults, i.e. urinary Sa, So levels, and Sa/So ratio are good biomarkers to assess FNs exposure in children.