title: Glucose transporter-1 distribution in fibrotic lung disease: association with [¹⁸F]-2-fluoro-2-deoxyglucose-PET scan uptake, inflammation, and neovascularization.
abstract: BACKGROUND
  [¹⁸F]-2-fluoro-2-deoxyglucose (FDG)-PET scan uptake is increased in areas of fibrosis and honeycombing in patients with idiopathic pulmonary fibrosis (IPF). Glucose transporter-1 (Glut-1) is known to be the main transporter for FDG. There is a paucity of data regarding the distribution of Glut-1 and the cells responsible for FDG binding in fibrotic lung diseases.
  
  
  METHODS
  We applied immunofluorescence to localize Glut-1 in normal, IPF, and Hermansky-Pudlak syndrome (HPS) pulmonary fibrosis lung tissue specimens as well as an array of 19 different lung neoplasms. In addition, we investigated Glut-1 expression in inflammatory cells from BAL fluid (BALF) from healthy volunteers, subjects with IPF, and subjects with HPS pulmonary fibrosis.
  
  
  RESULTS
  In normal lung tissue, Glut-1 immunoreactivity was seen on the surface of erythrocytes. In tissue sections from fibrotic lung diseases (IPF and HPS pulmonary fibrosis), Glut-1 immunoreactivity was present on the surface of erythrocytes and inflammatory cells. BALF inflammatory cells from healthy control subjects showed no immunoreactivity; BALF cells from subjects with IPF and HPS pulmonary fibrosis showed Glut-1 immunoreactivity associated with neutrophils and alveolar macrophages.
  
  
  CONCLUSIONS
  Glut-1 transporter expression in normal lung is limited to erythrocytes. In fibrotic lung, erythrocytes and inflammatory cells express Glut-1. Together, these data suggest that FDG-PET scan uptake in IPF could be explained by enhanced inflammatory and erythrocytes uptake due to neovascularization seen in IPF and not an upregulation of metabolic rate in pneumocytes. Thus, FDG-PET scan may detect inflammation and neovascularization in lung fibrosis.
authors.affiliation: Cardiovascular and Pulmonary Branch, National Institutes of Health, Bethesda, MD; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA. Electronic address: sel-chemaly@partners.org.
authors.forename: Souheil
authors.initials: S
authors.lastname: El-Chemaly
authors.affiliation: Light Microscopy Core Facility, National Institutes of Health, Bethesda, MD.
authors.forename: Daniela
authors.initials: D
authors.lastname: Malide
authors.affiliation: National Heart, Lung, and Blood Institute, the Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yao
authors.affiliation: Inova Fairfax Hospital, Falls Church, VA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Nathan
authors.affiliation: Cardiovascular and Pulmonary Branch, National Institutes of Health, Bethesda, MD; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Ivan O
authors.initials: IO
authors.lastname: Rosas
authors.affiliation: Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: William A
authors.initials: WA
authors.lastname: Gahl
authors.affiliation: Cardiovascular and Pulmonary Branch, National Institutes of Health, Bethesda, MD.
authors.forename: Joel
authors.initials: J
authors.lastname: Moss
authors.affiliation: Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Bernadette R
authors.initials: BR
authors.lastname: Gochuico
mesh_terms: D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D022861:Hermanski-Pudlak Syndrome / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000378:metabolism*; D049268:Positron-Emission Tomography; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics
chemical_list: D051272:Glucose Transporter Type 1; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18