title: A new approach to measuring vitamin D in human adipose tissue using time-of-flight secondary ion mass spectrometry: a pilot study.
abstract: Circulating concentrations of vitamin D, 25(OH)D, and 1,25(OH)2D are lower in obese than lean individuals, but little is known about the adipose tissue content of these molecules. The aim of this study was to explore the possibility to use time-of-flight secondary ion mass spectrometry (TOF-SIMS) to measure vitamin D and its metabolites in fat tissue in obese and lean subjects. Abdominal subcutaneous adipose tissue (SAT) biopsies were obtained from three lean and three obese women, and paired biopsies SAT and visceral adipose tissue (VAT) were obtained from three obese subjects during gastric bypass surgery. TOF-SIMS was used to measure vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in adipose tissue. We found that vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in adipose tissue can be measured with TOF-SIMS. In adipose tissue, vitamin D3 and its metabolites were located in adipocyte lipid droplets. The content of vitamin D3 (P=0.006) and 25(OH)D3 (P=0.018) were lower in SAT in obese compared with lean women. TOF-SIMS has the potential to semi-quantitatively measure vitamin D metabolites in adipose tissue, and offers a possibility to compare vitamin D levels in different depots and groups of individuals. It also gives the opportunity to explore the localization of vitamin D metabolites at a cellular level.
authors.affiliation: Department of Chemical and Biological Enigeneering, Analytical Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Malmberg
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden. Electronic address: therese.karlsson@k2.uib.no.
authors.forename: Therese
authors.initials: T
authors.lastname: Karlsson
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Svensson
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Lönn
authors.affiliation: Department of Chemical and Biological Engineering, Food Science, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Nils-Gunnar
authors.initials: NG
authors.lastname: Carlsson
authors.affiliation: Department of Chemical and Biological Engineering, Food Science, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Ann-Sofie
authors.initials: AS
authors.lastname: Sandberg
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Jennische
authors.affiliation: Department of Dermatology, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Amra
authors.initials: A
authors.lastname: Osmancevic
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Agneta
authors.initials: A
authors.lastname: Holmäng
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000378:metabolism / Q000473:pathology; D010865:Pilot Projects; D025341:Principal Component Analysis; D018629:Spectrometry, Mass, Secondary Ion; D014807:Vitamin D / Q000031:analogs & derivatives / Q000032:analysis* / Q000097:blood
chemical_list: D014807:Vitamin D
keywords: Adipose tissue; TOF-SIMS; Vitamin D