title: Deiodinase 2 expression is increased in dorsocervical fat of patients with HIV-associated lipohypertrophy syndrome.
abstract: BACKGROUND
  The pathogenesis and function of dorsocervical sc adipose tissue (DSAT) accumulation in HIV-infected patients is not known. Previous investigations using either UCP-1 expression or positron emission tomography have been inconclusive as to whether this depot represents brown adipose tissue (BAT). We investigated DSAT gene expression, including DIO2, a deiodinase that contributes to increased thermogenesis in brown fat, and simultaneously determined [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) uptake in lipodystrophic HIV and healthy control subjects.
  
  
  METHODS
  Thirteen HIV-infected and three non-HIV-infected men were recruited. HIV-infected subjects had evidence of significant lipodystrophy, including fat atrophy of the face, arms, and legs, and/or fat accumulation of the neck and abdomen. Subjects were cooled, followed by [¹⁸F]FDG positron emission tomography/computed tomography, fat biopsy of DSAT, and measurement of resting energy expenditure (REE). HIV-infected subjects were characterized as lipohypertrophic and lipoatrophic and compared.
  
  
  RESULTS
  Mean standardized uptake value of [¹⁸F]FDG and UCP-1 expression were not significantly different in DSAT among the groups. However, lipohypertrophic subjects demonstrated increased expression of DIO2 in DSAT compared with lipoatrophic subjects (P = 0.03). Among HIV-infected patients, DIO2 expression was strongly related to REE (r = 0.78, P = 0.002) and was a predictor of REE in multivariate modeling controlling for age, TSH, and lean body mass (r² = 0.79, P = 0.008). One control subject demonstrated typical BAT in the supraclavicular area.
  
  
  CONCLUSIONS
  Adipose tissue accumulating in the dorsocervical area in HIV lipodystrophy does not appear to be classical BAT. However, DIO2 expression is increased in DSAT among patients with HIV lipodystrophy, particularly those with increased visceral adiposity, and is positively associated with energy expenditure.
authors.affiliation: Division of Musculoskeletal Imaging and Intervention and Program in Nutritional Metabolism, Massachusetts General Hospital Longfellow 207, Boston, Massachusetts 02114, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Torriani
authors.forename: Kathleen
authors.initials: K
authors.lastname: Fitch
authors.forename: Eleni
authors.initials: E
authors.lastname: Stavrou
authors.forename: Miriam A
authors.initials: MA
authors.lastname: Bredella
authors.forename: Ruth
authors.initials: R
authors.lastname: Lim
authors.forename: Christina A
authors.initials: CA
authors.lastname: Sass
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Cypess
authors.forename: Steven
authors.initials: S
authors.lastname: Grinspoon
mesh_terms: D002001:Adipose Tissue, Brown / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D050154:Adiposity; D001284:Atrophy; D001415:Back; D001706:Biopsy; D015331:Cohort Studies; D004734:Energy Metabolism; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005947:Glucose / Q000378:metabolism; D039682:HIV-Associated Lipodystrophy Syndrome / Q000150:complications / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006984:Hypertrophy; D007453:Iodide Peroxidase / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D056128:Obesity, Abdominal / Q000150:complications; D049268:Positron-Emission Tomography; D050151:Subcutaneous Fat / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D015854:Up-Regulation; D000097564:Iodothyronine Deiodinase Type II
chemical_list: D019788:Fluorodeoxyglucose F18; D005947:Glucose; D007453:Iodide Peroxidase; D000097564:Iodothyronine Deiodinase Type II