Validation of urinary sphingolipid metabolites as biomarker of effect for fumonisins exposure in Kenyan children

Abstract

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 tumours in rodents and is associated with many human adverse health effects, including oesophageal cancer. International Agency for Research on Cancer (IARC) categorizes FB₁ as a 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 aged 1-14 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 the 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.

Keywords: Biomarker; fumonisins; mycotoxins; sphinganine; sphingolipids; sphingosine.