title: Brown adipose tissue triglyceride content is associated with decreased insulin sensitivity, independently of age and obesity.
abstract: The aim of the present study was to determine whether single-voxel proton magnetic resonance spectroscopy ((1)H-MRS) can non-invasively assess triglyceride content in both supraclavicular fat depots and subcutaneous white adipose tissue (WAT) to determine whether these measurements correlate to metabolic variables. A total of 25 healthy volunteers were studied using (18)F-fluorodeoxyglucose positron emission tomography (PET) and (15)O-H2O PET perfusion during cold exposure, and (1)H-MRS at ambient temperature. Image-guided biopsies were collected from nine volunteers. The supraclavicular triglyceride content determined by (1)H-MRS varied between 60 and 91% [mean ± standard deviation (s.d.) 77 ± 10%]. It correlated positively with body mass index, waist circumference, subcutaneous and visceral fat masses and 8-year diabetes risk based on the Framingham risk score and inversely with HDL cholesterol and insulin sensitivity (M-value; euglycaemic-hyperinsulinaemic clamp). Subcutaneous WAT had a significantly higher triglyceride content, 76-95% (mean ± s.d. 87 ± 5%; p = 0.0002). In conclusion, the triglyceride content in supraclavicular fat deposits measured by (1)H-MRS may be an independent marker of whole-body insulin sensitivity, independent of brown adipose tissue metabolic activation.
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Raiko
authors.forename: M
authors.initials: M
authors.lastname: Holstila
authors.forename: K A
authors.initials: KA
authors.lastname: Virtanen
authors.forename: J
authors.initials: J
authors.lastname: Orava
authors.forename: V
authors.initials: V
authors.lastname: Saunavaara
authors.forename: T
authors.initials: T
authors.lastname: Niemi
authors.forename: J
authors.initials: J
authors.lastname: Laine
authors.forename: M
authors.initials: M
authors.lastname: Taittonen
authors.forename: R J H
authors.initials: RJ
authors.lastname: Borra
authors.forename: P
authors.initials: P
authors.lastname: Nuutila
authors.forename: R
authors.initials: R
authors.lastname: Parkkola
mesh_terms: D050153:Abdominal Fat / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000737:chemistry*; D052436:Adipose Tissue, White / Q000737:chemistry; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D008076:Cholesterol, HDL; D019788:Fluorodeoxyglucose F18; D006801:Humans; D061705:Image-Guided Biopsy; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D009765:Obesity / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods; D066244:Proton Magnetic Resonance Spectroscopy; D019275:Radiopharmaceuticals / Q000032:analysis; D012306:Risk; D013696:Temperature; D014280:Triglycerides / Q000032:analysis*; D055105:Waist Circumference
chemical_list: D008076:Cholesterol, HDL; D007328:Insulin; D019275:Radiopharmaceuticals; D014280:Triglycerides; D019788:Fluorodeoxyglucose F18
keywords: 1H-MRS; MRI; adipose tissue; body composition