title: Mechanical stress related to brain atrophy in Alzheimer's disease.
abstract: BACKGROUND
  The effects related to endogenous mechanical energy in Alzheimer's disease (AD) pathology have been widely overlooked. With the support of available data from literature and mathematical arguments, we hypothesize that brain atrophy in AD could be co-driven by the cumulative impact of the pressure within brain tissues.
  
  
  METHODS
  Brain volumetric and physical data in AD and normal aging (NA) were extracted from the literature. Average brain shrinkage and axial deformations were evaluated mathematically. Mechanical stress equivalents related to brain shrinkage were calculated using a conservation law derived from fluid and solid mechanics.
  
  
  RESULTS
  Pressure equivalents of 5.92 and 3.43 mm Hg were estimated in AD and in NA, respectively.
  
  
  CONCLUSIONS
  The calculated increments of brain mechanical stress in AD, which could be impacted by marked dampening of arterial pulse waves, may point to the need to expand the focus on the mechanical processes underpinning pathologic aging of the brain.
authors.affiliation: Institut de la Mémoire et de la Maladie d'Alzheimer (IM2A), Département de Neurologie, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; Institut des Neurosciences Translationnelles de Paris (IHU-A-ICM), Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France; Laboratoire d'informatique (LIX), UMR 7161, Ecole Polytechnique, Université Paris-Saclay, Palaiseau, France. Electronic address: marcel.levy@psl.aphp.fr.
authors.forename: Marcel
authors.initials: M
authors.lastname: Levy Nogueira
authors.affiliation: LAGA, UMR 7539, Université Paris 13, Sorbonne Paris Cité, Villetaneuse, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lafitte
authors.affiliation: Laboratoire d'informatique (LIX), UMR 7161, Ecole Polytechnique, Université Paris-Saclay, Palaiseau, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Steyaert
authors.affiliation: Institut de la Mémoire et de la Maladie d'Alzheimer (IM2A), Département de Neurologie, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; Institut des Neurosciences Translationnelles de Paris (IHU-A-ICM), Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France.
authors.forename: Hovagim
authors.initials: H
authors.lastname: Bakardjian
authors.affiliation: Institut de la Mémoire et de la Maladie d'Alzheimer (IM2A), Département de Neurologie, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; Institut des Neurosciences Translationnelles de Paris (IHU-A-ICM), Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France; INSERM, CNRS, UMR-S975, Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Dubois
authors.affiliation: Institut de la Mémoire et de la Maladie d'Alzheimer (IM2A), Département de Neurologie, Hôpital de la Pitié-Salpêtrière, AP-HP, Paris, France; INSERM, CNRS, UMR-S975, Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France; AXA Research Fund & UPMC Chair, Sorbonne Universités, Université Pierre et Marie Curie, Paris, France.
authors.forename: Harald
authors.initials: H
authors.lastname: Hampel
authors.affiliation: Laboratoire d'informatique (LIX), UMR 7161, Ecole Polytechnique, Université Paris-Saclay, Palaiseau, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009929:Organ Size; D011312:Pressure; D013314:Stress, Mechanical; D055815:Young Adult
keywords: Alzheimer's disease; Brain atrophy; Brain stiffness; Fluid mechanics; Mechanical stress; Total brain volume