title: Fatty acid ethyl esters (FAEE); comparative accumulation in human and guinea pig hair as a biomarker for prenatal alcohol exposure.
abstract: OBJECTIVE
  To compare the incorporation rate (ICR) of fatty acid ethyl esters (FAEE) in hair between guinea pigs and humans, and to assess the relationship between ethanol exposure and FAEE concentrations in hair.
  
  
  METHODS
  Published data from pregnant guinea pigs, including maximum blood ethanol concentration (BEC), dosage regimen, and total hair FAEE concentration, were compared with published data from alcoholic patients, where dose of ethanol consumed and total hair FAEE concentration were reported. Mean values of ethanol Vmax for pregnant guinea pigs and humans were obtained from published data (26.2 and 24 mg/dl/h, respectively).
  
  
  RESULTS
  Total and individual FAEE ICRs, defined as the ratio of hair FAEE to the area under the BEC-time curve (total systemic ethanol exposure), were found to be on average an order of magnitude lower in the guinea pig than in the human. The profiles of ester incorporation also differed slightly between species, with ethyl stearate being highly incorporated in guinea pig hair and less so in human hair. The results may reflect in the human greater FAEE production, greater FAEE deposition in hair, slower FAEE catabolism, differential sebum production and composition, or a combination thereof. Also, ethyl oleate was found to correlate with total systemic ethanol exposure for both guinea pigs and humans, correlation coefficients equalling 0.67 (P < 0.05) and 0.49 (P < 0.05), respectively. No other ethyl esters, nor total FAEE, were found to correlate with systemic ethanol exposure.
  
  
  CONCLUSIONS
  When extrapolating FAEE concentrations in hair from guinea pigs to humans, an order of magnitude difference should be considered, with humans incorporating more FAEE per unit of ethanol exposure. Also, the results suggest caution should be taken when interpreting values of single esters because of their differential incorporation among species. Lastly, our findings suggest ethyl oleate may be of keen interest in FAEE hair analysis, particularly across species.
authors.affiliation: Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Vivian
authors.initials: V
authors.lastname: Kulaga
authors.forename: Daniela
authors.initials: D
authors.lastname: Caprara
authors.forename: Umar
authors.initials: U
authors.lastname: Iqbal
authors.forename: Bhushan
authors.initials: B
authors.lastname: Kapur
authors.forename: Julia
authors.initials: J
authors.lastname: Klein
authors.forename: James
authors.initials: J
authors.lastname: Reynolds
authors.forename: James
authors.initials: J
authors.lastname: Brien
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
mesh_terms: D000328:Adult; D000818:Animals; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis*; D004952:Esters / Q000032:analysis; D000431:Ethanol / Q000633:toxicity*; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D063647:Fetal Alcohol Spectrum Disorders / Q000175:diagnosis*; D006168:Guinea Pigs; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy
chemical_list: D015415:Biomarkers; D004952:Esters; D005227:Fatty Acids; D000431:Ethanol