title: Increased Lung Expression of Anti-Angiogenic Factors in Down Syndrome: Potential Role in Abnormal Lung Vascular Growth and the Risk for Pulmonary Hypertension.
abstract: OBJECTIVE
  Infants with Down syndrome (DS) or Trisomy 21, are at high risk for developing pulmonary arterial hypertension (PAH), but mechanisms that increase susceptibility are poorly understood. Laboratory studies have shown that early disruption of angiogenesis during development impairs vascular and alveolar growth and causes PAH. Human chromosome 21 encodes known anti-angiogenic factors, including collagen18a1 (endostatin, ES), ß-amyloid peptide (BAP) and Down Syndrome Critical Region 1 (DSCR-1). Therefore, we hypothesized that fetal lungs from subjects with DS are characterized by early over-expression of anti-angiogenic factors and have abnormal lung vascular growth in utero.
  
  
  METHODS
  Human fetal lung tissue from DS and non-DS subjects were obtained from a biorepository. Quantitative reverse transcriptase PCR (qRT-PCR) was performed to assay 84 angiogenesis-associated genes and individual qRT-PCR was performed for ES, amyloid protein precursor (APP) and DSCR1. Western blot analysis (WBA) was used to assay lung ES, APP and DSCR-1 protein contents. Lung vessel density and wall thickness were determined by morphometric analysis.
  
  
  RESULTS
  The angiogenesis array identified up-regulation of three anti-angiogenic genes: COL18A1 (ES), COL4A3 (tumstatin) and TIMP3 (tissue inhibitor of metallopeptidase 3) in DS lungs. Single qRT-PCR and WBA showed striking elevations of ES and APP mRNA (p = 0.022 and p = 0.001) and protein (p = 0.040 and p = 0.002; respectively). Vessel density was reduced (p = 0.041) and vessel wall thickness was increased in DS lung tissue (p = 0.033) when compared to non-DS subjects.
  
  
  CONCLUSIONS
  We conclude that lung anti-angiogenic factors, including COL18A1 (ES), COL4A3, TIMP3 and APP are over-expressed and fetal lung vessel growth is decreased in subjects with DS. We speculate that increased fetal lung anti-angiogenic factor expression due to trisomy 21 impairs lung vascular growth and signaling, which impairs alveolarization and contributes to high risk for PAH during infancy.
authors.affiliation: Departments of Pathology and Laboratory Medicine, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.|The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Csaba
authors.initials: C
authors.lastname: Galambos
authors.affiliation: Departments of Pathology and Laboratory Medicine, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.|The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Angela D
authors.initials: AD
authors.lastname: Minic
authors.affiliation: Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.|The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Douglas
authors.initials: D
authors.lastname: Bush
authors.affiliation: University of Notre Dame, South Bend, Indiana, United States of America.
authors.forename: Dominique
authors.initials: D
authors.lastname: Nguyen
authors.affiliation: Pediatric Surgery, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.|The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Blair
authors.initials: B
authors.lastname: Dodson
authors.affiliation: The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Gregory
authors.initials: G
authors.lastname: Seedorf
authors.affiliation: Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.|The Pediatric Heart Lung Center, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Abman
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000235:genetics* / Q000378:metabolism; D001324:Autoantigens / Q000235:genetics* / Q000378:metabolism; D024141:Collagen Type IV / Q000235:genetics* / Q000378:metabolism; D024102:Collagen Type VIII / Q000235:genetics* / Q000378:metabolism; D043170:Collagen Type XVIII; D004268:DNA-Binding Proteins; D004314:Down Syndrome / Q000150:complications / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000002:abnormalities* / Q000196:embryology / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D001324:Autoantigens; C000612902:COL18A1 protein, human; D024141:Collagen Type IV; D024102:Collagen Type VIII; D043170:Collagen Type XVIII; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; C108612:RCAN1 protein, human; C088390:TIMP3 protein, human; D019717:Tissue Inhibitor of Metalloproteinase-3; C057112:type IV collagen alpha3 chain