title: Blood flow modulation of vascular dynamics.
abstract: OBJECTIVE
  Blood flow is intimately linked with cardiovascular development, repair and dysfunction. The current review will build on the fluid mechanical principle underlying haemodynamic shear forces, mechanotransduction and metabolic effects.
  
  
  RESULTS
  Pulsatile flow produces both time (∂τ/∂t) and spatial-varying shear stress (∂τ/∂x) to modulate vascular oxidative stress and inflammatory response with pathophysiological significance to atherosclerosis. The characteristics of haemodynamic shear forces, namely, steady laminar (∂τ/∂t = 0), pulsatile shear stress (PSS: unidirectional forward flow) and oscillatory shear stress (bidirectional with a near net 0 forward flow), modulate mechano-signal transduction to influence metabolic effects on vascular endothelial function. Atheroprotective PSS promotes antioxidant, anti-inflammatory and antithrombotic responses, whereas atherogenic oscillatory shear stress induces nicotinamide adenine dinucleotide phosphate oxidase-JNK signalling to increase mitochondrial superoxide production, protein degradation of manganese superoxide dismutase and post-translational protein modifications of LDL particles in the disturbed flow-exposed regions of vasculature. In the era of tissue regeneration, shear stress has been implicated in reactivation of developmental genes, namely, Wnt and Notch signalling, for vascular development and repair.
  
  
  CONCLUSIONS
  Blood flow imparts a dynamic continuum from vascular development to repair. Augmentation of PSS confers atheroprotection and reactivation of developmental signalling pathways for regeneration.
authors.affiliation: aDepartment of Bioengineering bDepartment of Molecular, Cellular and Integrative Physiology cDivision of Cardiology, Department of Medicine, University of California, Los Angeles, Los Angeles, California, USA *Juhyun Lee and René R. Sevag Packard contributed equally to the writing of this article.
authors.forename: Juhyun
authors.initials: J
authors.lastname: Lee
authors.forename: René R Sevag
authors.initials: RR
authors.lastname: Packard
authors.forename: Tzung K
authors.initials: TK
authors.lastname: Hsiai
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000503:physiopathology; D001696:Biomechanical Phenomena; D004730:Endothelium, Vascular / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D040542:Mechanotransduction, Cellular; D018384:Oxidative Stress; D012039:Regional Blood Flow; D015398:Signal Transduction