title: Brown fat activity is not apparent in subjects with HIV lipodystrophy and increased resting energy expenditure.
abstract: The HIV lipodystrophy (LD) syndrome is associated with increased resting energy expenditure (REE), but the basis of this hypermetabolism has not been determined. The objective of this pilot study was to determine if brown fat is activated in subjects with HIV LD and increased REE. In this descriptive study of four subjects with HIV LD and marked hypermetabolism, REE was measured by indirect calorimetry and brown fat activity was determined by (18)F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) combined with anatomic computed tomography (CT). Brown fat activity was not apparent in any subject with HIV LD and resting hypermetabolism. Therefore, brown fat activation is unlikely to be the principal cause of the increased REE associated with the HIV LD syndrome. Evidence of adaptive thermogenesis has been demonstrated in this syndrome, but this study suggests that tissues other than brown adipose tissue (BAT) are responsible. Further understanding of the chronic hypermetabolism associated with HIV LD could provide new insights into the regulation of energy balance.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, School of Medicine, University of Colorado, Aurora, Colorado, USA. lisa.kosmiski@ucdenver.edu
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Kosmiski
authors.forename: Adrienne
authors.initials: A
authors.lastname: Sage-El
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Kealey
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Bessesen
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000328:Adult; D001481:Basal Metabolism; D002153:Calorimetry, Indirect; D006678:HIV; D015658:HIV Infections / Q000150:complications / Q000378:metabolism*; D006801:Humans; D008060:Lipodystrophy / Q000209:etiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012146:Rest / Q000502:physiology*; D022722:Thermogenesis; D014054:Tomography