title: Anisotropic stretch-induced hypertrophy in neonatal ventricular myocytes micropatterned on deformable elastomers.
abstract: Because cell shape and alignment, cell-matrix adhesion, and cell-cell contact can all affect growth, and because mechanical strains in vivo are multiaxial and anisotropic, we developed an in vitro system for engineering aligned, rod-shaped, neonatal cardiac myocyte cultures. Photolithographic and microfluidic techniques were used to micropattern extracellular matrices in parallel lines on deformable silicone elastomers. Confluent, elongated, aligned myocytes were produced by varying the micropattern line width and collagen density. An elliptical cell stretcher applied 2:1 anisotropic strain statically to the elastic substrate, with the axis of greatest stretch (10%) either parallel or transverse to the myofibrils. After 24 h, the principal strain parallel to myocytes did not significantly alter myofibril accumulation or expression of atrial natriuretic factor (ANF), connexin-43 (Cx-43), or N-cadherin (by indirect immunofluorescent antibody labeling and immunoblotting) compared with unstretched controls. In contrast, 10% transverse principal strain resulted in continuous staining of actin filaments (rhodamine phalloidin); increased immunofluorescent labeling of ANF, Cx-43, and N-cadherin; and upregulation of protein signal intensity by western blotting. By using microfabrication and microfluidics to control cell shape and alignment on an elastic substrate, we found greater effects for transverse than for longitudinal stretch in regulating sarcomere organization, hypertrophy, and cell-to-cell junctions.
authors.affiliation: Department of Bioengineering, Whitaker Institute for Biomedical Engineering, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0412, USA.
authors.forename: Sindhu M
authors.initials: SM
authors.lastname: Gopalan
authors.forename: Chris
authors.initials: C
authors.lastname: Flaim
authors.forename: Sangeeta N
authors.initials: SN
authors.lastname: Bhatia
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hoshijima
authors.forename: Ralph
authors.initials: R
authors.lastname: Knoell
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Chien
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Omens
authors.forename: Andrew D
authors.initials: AD
authors.lastname: McCulloch
mesh_terms: D000199:Actins / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D016880:Anisotropy; D009320:Atrial Natriuretic Factor / Q000502:physiology; D015820:Cadherins / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D003094:Collagen / Q000502:physiology; D018031:Connexin 43 / Q000502:physiology; D004548:Elasticity; D006352:Heart Ventricles / Q000166:cytology / Q000503:physiopathology; D006984:Hypertrophy / Q000503:physiopathology; D008567:Membranes, Artificial; D008846:Micromanipulation / Q000295:instrumentation / Q000379:methods*; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology*; D010781:Photography / Q000295:instrumentation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012212:Rheology / Q000295:instrumentation / Q000379:methods; D012826:Silicone Elastomers; D013314:Stress, Mechanical
chemical_list: D000199:Actins; D015820:Cadherins; D018031:Connexin 43; D008567:Membranes, Artificial; D012826:Silicone Elastomers; D009320:Atrial Natriuretic Factor; D003094:Collagen