title: The isotropic fractionator provides evidence for differential loss of hippocampal neurons in two mouse models of Alzheimer's disease.
abstract: BACKGROUND
  The accumulation of amyloid beta (Aβ) oligomers or fibrils is thought to be one of the main causes of synaptic and neuron loss, believed to underlie cognitive dysfunction in Alzheimer's disease (AD). Neuron loss has rarely been documented in amyloid precursor protein (APP) transgenic mouse models. We investigated whether two APP mouse models characterized by different folding states of amyloid showed different neuronal densities using an accurate method of cell counting.
  
  
  RESULTS
  We examined total cell and neuronal populations in Swedish/Indiana APP mutant mice (TgCRND8) with severe Aβ pathology that includes fibrils, plaques, and oligomers, and Dutch APP mutant mice with only Aβ oligomer pathology. Using the isotropic fractionator, we found no differences from control mice in regional total cell populations in either TgCRND8 or Dutch mice. However, there were 31.8% fewer hippocampal neurons in TgCRND8 compared to controls, while no such changes were observed in Dutch mice.
  
  
  CONCLUSIONS
  We show that the isotropic fractionator is a convenient method for estimating neuronal content in milligram quantities of brain tissue and represents a useful tool to assess cell loss efficiently in transgenic models with different types of neuropathology. Our data support the hypothesis that TgCRND8 mice with a spectrum of Aβ plaque, fibril, and oligomer pathology exhibit neuronal loss whereas Dutch mice with only oligomers, showed no evidence for neuronal loss. This suggests that the combination of plaques, fibrils, and oligomers causes more damage to mouse hippocampal neurons than Aβ oligomers alone.
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Brautigam
authors.forename: John W
authors.initials: JW
authors.lastname: Steele
authors.forename: David
authors.initials: D
authors.lastname: Westaway
authors.forename: Paul E
authors.initials: PE
authors.lastname: Fraser
authors.forename: Peter H
authors.initials: PH
authors.lastname: St George-Hyslop
authors.forename: Sam
authors.initials: S
authors.lastname: Gandy
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Hof
authors.forename: Dara L
authors.initials: DL
authors.lastname: Dickstein
mesh_terms: D000544:Alzheimer Disease / Q000473:pathology*; D000818:Animals; D002452:Cell Count / Q000379:methods*; D002458:Cell Fractionation / Q000379:methods*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000473:pathology*; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000473:pathology*