title: Comparison of three different sampling methods for canine skin lipids.
abstract: BACKGROUND
  Epidermal lipids are of major interest in dermatological research, especially in canine atopic dermatitis. Owing to the existence of several sampling methods, the interpretation of study results is often complicated.
  
  
  OBJECTIVE
  This study aimed to compare three different sampling methods and to establish a minimally invasive method for collecting canine epidermal lipids.
  
  
  METHODS
  Skin samples from five dogs with no obvious skin abnormalities were taken from the caudal back and the inguinal region postmortem. Samples consisted of heat-separated epidermis of three skin biopsies, three scrapes and three skin scrubs. Lipids were analysed by high-performance thin-layer chromatography; the resulting bands were identified by using corresponding standards, retardation factors and mass spectrometry. The influences of the sampling method, the body site and the ceramide standards were investigated.
  
  
  RESULTS
  Between body sites, significant differences were found for cholesterol sulphate, cholesteryl esters and triglycerides. Significant differences between sampling methods were detected for all lipid fractions except for cholesterol sulphate and glucosylceramides within the lipid profile, and for at least four ceramide classes within the ceramide profile. The most obvious discrepancies were found between heat-separated epidermis and skin scrub. The reproducibility was high for scraping and skin scrub, but was lowest for heat-separated epidermis. Furthermore, this study revealed a marked influence of ceramide standards on the results regarding the ceramide profile.
  
  
  CONCLUSIONS
  Scraping and skin scrub are comparably suitable methods for skin lipid sampling, whereas the analysis of heat-separated epidermis may not be the method of first choice.
authors.affiliation: Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Buenteweg 9, Hanover, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Angelbeck-Schulze
authors.forename: Jessica
authors.initials: J
authors.lastname: Stahl
authors.forename: Susanne
authors.initials: S
authors.lastname: Brodesser
authors.forename: Karl
authors.initials: K
authors.lastname: Rohn
authors.forename: Hassan
authors.initials: H
authors.lastname: Naim
authors.forename: Marion
authors.initials: M
authors.lastname: Hewicker-Trautwein
authors.forename: Manfred
authors.initials: M
authors.lastname: Kietzmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bäumer
authors.forename: Reinhard
authors.initials: R
authors.lastname: Mischke
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004285:Dogs / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology*; D008055:Lipids / Q000032:analysis* / Q000737:chemistry; D013058:Mass Spectrometry / Q000662:veterinary; D015203:Reproducibility of Results; D015983:Selection Bias; D012867:Skin / Q000737:chemistry* / Q000378:metabolism; D013048:Specimen Handling / Q000379:methods / Q000662:veterinary*
chemical_list: D008055:Lipids