title: The lung innate immune gene surfactant protein-D is expressed in adipose tissue and linked to obesity status.
abstract: BACKGROUND
  Surfactant protein-D (SFTPD) is a component of the lung innate immunity that enhances clearance of pathogens and modulates inflammatory responses. An inverse association of putative, lung-derived circulating SFTPD with obesity has been reported but no information is available concerning possible SFTPD gene expression in human adipose tissue.
  
  
  METHODS
  SFTPD gene expression was analyzed in human omental (OM; n=156) and subcutaneous (SC; n=106) adipose tissue, and in isolated fat cells (n=12) in association with measures of obesity and glucose tolerance.
  
  
  RESULTS
  SFTPD gene was expressed in human adipose tissue and adipocytes. This expression was decreased in OM and SC adipose tissue from obese subjects with (-47%, P<0.0001; and -37%, P=0.048) and without (-34%, P=0.001; and -22%, P=0.08; respectively) type 2 diabetes when compared with the control group. Indeed, OM SFTPD was inversely associated with body mass index (r=-0.33, P<0.0001), percent fat mass (r=-0.36, P<0.0001), waist perimeter (r=-0.26, P=0.002), diastolic blood pressure (r=-0.21, P=0.018) and fasting glucose (r=-0.21, P=0.012); and positively linked to the expression of insulin receptor substrate 1 (IRS1; r=0.25, P=0.004), perilipin A (PLIN; r=0.38, P=0.007) and fatty acid synthase (FASN; r=0.36, P<0.0001). Accordingly, increased SFTPD (4.5-fold, P=0.02) was detected in isolated adipocytes when compared with the stromal-vascular cell fraction, in parallel to IRS1, FASN and PLIN.
  
  
  CONCLUSIONS
  Both OM and SC adipose tissue (mainly mature adipocytes) express SFTPD. This expression decreases with obesity and impaired glucose tolerance.
authors.affiliation: 1] CIBER de la Fisiopatología de la Obesidad y la Nutrición (CIBERobn, CB06/03/0010) and Instituto de Salud Carlos III (ISCIII), Santiago de Compostela, Spain [2] Service of Diabetes, Endocrinology and Nutrition (UDEN), Institut d'Investigació Biomédica de Girona (IdIBGi), Girona, Spine.
authors.forename: F J
authors.initials: FJ
authors.lastname: Ortega
authors.forename: N
authors.initials: N
authors.lastname: Pueyo
authors.forename: J M
authors.initials: JM
authors.lastname: Moreno-Navarrete
authors.forename: M
authors.initials: M
authors.lastname: Sabater
authors.forename: J I
authors.initials: JI
authors.lastname: Rodriguez-Hermosa
authors.forename: W
authors.initials: W
authors.lastname: Ricart
authors.forename: F J
authors.initials: FJ
authors.lastname: Tinahones
authors.forename: J M
authors.initials: JM
authors.lastname: Fernández-Real
mesh_terms: D015992:Body Mass Index; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007249:Inflammation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000276:immunology* / Q000378:metabolism; D009852:Omentum / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D037663:Pulmonary Surfactant-Associated Protein D / Q000276:immunology / Q000378:metabolism*; D050151:Subcutaneous Fat / Q000276:immunology* / Q000378:metabolism
chemical_list: D037663:Pulmonary Surfactant-Associated Protein D