title: Time course of metabolic activity and cellular infiltration in a murine model of acid-induced lung injury.
abstract: OBJECTIVE
  This study investigates whether positron emission tomography (PET) can be used to monitor the inflammatory response and its correlation with the later fibroproliferative phase in an experimental model of acute lung injury.
  
  
  METHODS
  Hydrochloric acid (0.1 N, pH 1, 1.5 ml/kg) was instilled into the right bronchus of mice. A group of mice underwent a micro-computed tomography (CT) scan 1 h after lung injury and a series of 2-[(18)F]fluorine-2-deoxy-D: -glucose (FDG)-PET scans (6, 24 and 48 h and 7 days after surgery). After 21 days respiratory static compliance was assessed and lung tissue was collected in order to measure the hydroxy (OH)-proline content. Other groups of mice underwent micro-CT and micro-PET scans at the same time points, and then were immediately killed to assess arterial blood gases and histology.
  
  
  RESULTS
  Histological analysis showed the recruitment of neutrophils and macrophages into the damaged lung, reaching the peak at 24 and 48 h, respectively. The time course of the [(18)F]FDG signal, used as a marker of inflammation, correlated with that of recruited inflammatory cells. In mice killed 21 days after the surgery, a correlation was found between reduced respiratory static compliance and high PET signal 7 days after lung injury. The PET signal also correlated with the OH-proline content.
  
  
  CONCLUSIONS
  This study demonstrated that PET imaging is a valid means of tracking the inflammatory response, also in longitudinal studies. Moreover, a correlation was found between persistence of the inflammatory response and fibrotic evolution of the injury.
authors.affiliation: Department of Experimental Medicine (DIMS), University of Milan-Bicocca, Via Cadore 48, 20900 Monza, MB, Italy.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Zambelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Di Grigoli
authors.forename: Margherita
authors.initials: M
authors.lastname: Scanziani
authors.forename: Silvia
authors.initials: S
authors.lastname: Valtorta
authors.forename: Maria
authors.initials: M
authors.lastname: Amigoni
authors.forename: Sara
authors.initials: S
authors.lastname: Belloli
authors.forename: Cristina
authors.initials: C
authors.lastname: Messa
authors.forename: Antonio
authors.initials: A
authors.lastname: Pesenti
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Fazio
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bellani
authors.forename: Rosa Maria
authors.initials: RM
authors.lastname: Moresco
mesh_terms: D055371:Acute Lung Injury / Q000000981:diagnostic imaging* / Q000378:metabolism; D000818:Animals; D001784:Blood Gas Analysis; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005260:Female; D019788:Fluorodeoxyglucose F18; D006851:Hydrochloric Acid; D006909:Hydroxyproline / Q000378:metabolism; D007249:Inflammation / Q000000981:diagnostic imaging / Q000378:metabolism; D016014:Linear Models; D008264:Macrophages / Q000502:physiology; D051379:Mice; D020556:Neutrophil Infiltration; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013997:Time Factors; D055114:X-Ray Microtomography
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D006851:Hydrochloric Acid; D006909:Hydroxyproline