title: Sphinganine/sphingosine ratio in plasma and urine as a possible biomarker for fumonisin exposure in humans in rural areas of Africa.
abstract: This study was conducted in the Transkei region of the Eastern Cape and KwaZulu-Natal province, South Africa and in the Bomet district, western Kenya. The sphinganine (Sa)/sphingosine (So) ratios in the plasma and urine of male and female volunteers consuming a staple diet of home-grown maize in Transkei, were 0.34 +/- 0.36 (mean +/- standard deviation) (n = 154) and 0.41 +/- 0.72 (n = 153), respectively and in plasma samples from KwaZulu-Natal it was 0.44 +/- 0.23 (n = 26). In Kenya, the ratios in plasma and urine were 0.28 +/- 0.07 (n = 29) and 0.34 +/- 0.20 (n = 27), respectively. Mean total fumonisin level in home-grown maize, randomly collected in Transkei from the same region where the human volunteers lived, was 580 ng/g (n = 40), as compared to the KwaZulu-Natal province, where no fumonisin (n = 17) were detected (< 10 ng/g) in the home-grown maize. In Kenya, only one of seven samples was contaminated with 60 ng/g fumonisins. No significant differences were found in the Sa/So ratios between males and females within the regions nor between the different regions (P > 0.05). It is possible that the ratio is not sensitive enough to act as a biomarker for fumonisin exposure in humans at these levels of contamination in maize. This is the first report on Sa/So ratios determined in rural populations in Africa consuming home-grown maize as their staple diet.
authors.affiliation: Programme on Mycotoxins and Experimental Carcinogenesis, Medical Research Council, Tygerberg, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: van der Westhuizen
authors.forename: N L
authors.initials: NL
authors.lastname: Brown
authors.forename: W F
authors.initials: WF
authors.lastname: Marasas
authors.forename: S
authors.initials: S
authors.lastname: Swanevelder
authors.forename: G S
authors.initials: GS
authors.lastname: Shephard
mesh_terms: D000349:Africa; D015415:Biomarkers / Q000097:blood* / Q000652:urine; D002264:Carboxylic Acids / Q000633:toxicity*; D004032:Diet; D005260:Female; D037341:Fumonisins; D006801:Humans; D008297:Male; D012424:Rural Population; D013050:Spectrometry, Fluorescence; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003313:Zea mays / Q000737:chemistry
chemical_list: D015415:Biomarkers; D002264:Carboxylic Acids; D037341:Fumonisins; C056933:fumonisin B1; D013110:Sphingosine; C005682:safingol