title: Long-term functional outcomes and correlation with regional brain connectivity by MRI diffusion tractography metrics in a near-term rabbit model of intrauterine growth restriction.
abstract: BACKGROUND
  Intrauterine growth restriction (IUGR) affects 5-10% of all newborns and is associated with increased risk of memory, attention and anxiety problems in late childhood and adolescence. The neurostructural correlates of long-term abnormal neurodevelopment associated with IUGR are unknown. Thus, the aim of this study was to provide a comprehensive description of the long-term functional and neurostructural correlates of abnormal neurodevelopment associated with IUGR in a near-term rabbit model (delivered at 30 days of gestation) and evaluate the development of quantitative imaging biomarkers of abnormal neurodevelopment based on diffusion magnetic resonance imaging (MRI) parameters and connectivity.
  
  
  METHODS
  At +70 postnatal days, 10 cases and 11 controls were functionally evaluated with the Open Field Behavioral Test which evaluates anxiety and attention and the Object Recognition Task that evaluates short-term memory and attention. Subsequently, brains were collected, fixed and a high resolution MRI was performed. Differences in diffusion parameters were analyzed by means of voxel-based and connectivity analysis measuring the number of fibers reconstructed within anxiety, attention and short-term memory networks over the total fibers.
  
  
  RESULTS
  The results of the neurobehavioral and cognitive assessment showed a significant higher degree of anxiety, attention and memory problems in cases compared to controls in most of the variables explored. Voxel-based analysis (VBA) revealed significant differences between groups in multiple brain regions mainly in grey matter structures, whereas connectivity analysis demonstrated lower ratios of fibers within the networks in cases, reaching the statistical significance only in the left hemisphere for both networks. Finally, VBA and connectivity results were also correlated with functional outcome.
  
  
  CONCLUSIONS
  The rabbit model used reproduced long-term functional impairments and their neurostructural correlates of abnormal neurodevelopment associated with IUGR. The description of the pattern of microstructural changes underlying functional defects may help to develop biomarkers based in diffusion MRI and connectivity analysis.
authors.affiliation: Department of Maternal-Fetal Medicine, Institut Clinic de Ginecologia, Obstetricia i Neonatologia (ICGON), Hospital Clinic, Barcelona, Spain ; Fetal and Perinatal Medicine Research Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Illa
authors.forename: Elisenda
authors.initials: E
authors.lastname: Eixarch
authors.forename: Dafnis
authors.initials: D
authors.lastname: Batalle
authors.forename: Ariadna
authors.initials: A
authors.lastname: Arbat-Plana
authors.forename: Emma
authors.initials: E
authors.lastname: Muñoz-Moreno
authors.forename: Francesc
authors.initials: F
authors.lastname: Figueras
authors.forename: Eduard
authors.initials: E
authors.lastname: Gratacos
mesh_terms: D000818:Animals; D001007:Anxiety / Q000473:pathology / Q000503:physiopathology; D001288:Attention / Q000502:physiology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology; D056324:Diffusion Tensor Imaging; D004195:Disease Models, Animal; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology*; D008568:Memory / Q000502:physiology; D009415:Nerve Net / Q000473:pathology* / Q000503:physiopathology*; D011247:Pregnancy; D011817:Rabbits