title: Caffeine induces alveolar apoptosis in the hyperoxia-exposed developing mouse lung.
abstract: BACKGROUND
  Caffeine is a nonspecific adenosine receptor antagonist used in premature neonates to treat apnea of prematurity. While its use may reduce the incidence of bronchopulmonary dysplasia (BPD), the precise mechanisms remain unknown. Evidence of increased adenosine levels are noted in chronic lung diseases including tracheal aspirates of infants with BPD. Utilizing a well-characterized newborn mouse model of alveolar hypoplasia, we hypothesized that hyperoxia-induced alveolar inflammation and hypoplasia is associated with alterations in the adenosine signaling pathway.
  
  
  METHODS
  Newborn murine pups were exposed to a 14-d period of hyperoxia and daily caffeine administration followed by a 14-d recovery period in room air. Lungs were collected at both time points for bronchoalveolar lavage (BAL) analysis as well as histopathology and mRNA and protein expression.
  
  
  RESULTS
  Caffeine treatment increased inflammation and worsened alveolar hypoplasia in hyperoxia-exposed newborn mice. These changes were associated with decreased alveolar type II (ATII) cell numbers, increased cell apoptosis, and decreased expression of A2A receptors. Following discontinuation of caffeine and hyperoxia, lung histology returned to baseline levels comparable to hyperoxia exposure alone.
  
  
  CONCLUSIONS
  Results of this study suggest a potentially adverse role of caffeine on alveolar development in a murine model of hyperoxia-induced alveolar hypoplasia.
authors: Department of Pediatrics, Division of Neonatology and Developmental Biology, David Geffen School of Medicine, Neonatal Research Center, University of California, Los Angeles, California.
authors: Sara
authors: S
authors: Dayanim
authors: Department of Pediatrics, Division of Neonatology and Developmental Biology, David Geffen School of Medicine, Neonatal Research Center, University of California, Los Angeles, California.
authors: Benjamin
authors: B
authors: Lopez
authors: Department of Pediatrics, Division of Neonatology and Developmental Biology, David Geffen School of Medicine, Neonatal Research Center, University of California, Los Angeles, California.
authors: Tiffany M
authors: TM
authors: Maisonet
authors: Department of Pediatrics, Division of Neonatology and Developmental Biology, David Geffen School of Medicine, Neonatal Research Center, University of California, Los Angeles, California.
authors: Sungat
authors: S
authors: Grewal
authors: Department of Pediatrics, Division of Neonatology and Developmental Biology, David Geffen School of Medicine, Neonatal Research Center, University of California, Los Angeles, California.
authors: Vedang A
authors: VA
authors: Londhe
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D018893:Bronchoalveolar Lavage; D002110:Caffeine / Q000008:administration & dosage / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D051379:Mice; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects* / Q000503:physiopathology; D058915:Purinergic P1 Receptor Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D043705:Receptor, Adenosine A2A / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D058915:Purinergic P1 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D002110:Caffeine; D000241:Adenosine